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Books
Tavakoli M (2022).
Diabetic Neuropathy.Abstract:
Diabetic Neuropathy
Abstract.
Journal articles
Tavakoli M (In Press). Ophthalmic Biomarkers of Alzheimer's disease: a review. Frontiers in Aging Neuroscience
Al-Hinnawi A-RM, BaniMustafa A, Al-Latayfeh M, Tavakoli M (2023). Reconstruction and Visualization of 5μm Sectional Coronal Views for Macula Vasculature in OptoVue OCTA. IEEE Access, 11, 28280-28293.
Pacaud D, Romanchuk KG, Virtanen H, Ferdousi M, Nettel-Aguirre A, Mah JK, Tavakoli M, Zochodne DW, Malik RA (2022). Corneal nerve and nerve conduction abnormalities in children with type 1 diabetes.
Pediatr Diabetes,
23(8), 1665-1673.
Abstract:
Corneal nerve and nerve conduction abnormalities in children with type 1 diabetes.
OBJECTIVE: in vivo corneal confocal microscopy (CCM) is a novel, rapid, and non-invasive technique that identifies early small fiber damage and can predict the progression and development of clinical neuropathy in adults with type 1 diabetes. However, its usefulness in children is not well established. This study compared corneal confocal microscopy with neuropathic symptoms, signs, and objective measures of neuropathy for the diagnosis of diabetic neuropathy in children with type 1 diabetes. RESEARCH DESIGN AND METHODS: a total of 83 children with type 1 diabetes and 83 healthy participants of similar age underwent assessment of neuropathy symptoms, signs, nerve conduction studies, quantitative sensory and autonomic function testing, and in vivo CCM. RESULTS: Only of 3/83 (4%) children with type 1 diabetes had subclinical neuropathy. However, corneal nerve fiber density (p = 0.001), branch density (p = 0.006), fiber length (p = 0.002), tibial motor nerve amplitude and conduction velocity, and sural sensory nerve amplitude and conduction velocity (all p 0.05) between children with type 1 diabetes and healthy controls. Multivariate regression analysis identified a possible association between body mass index and decreased corneal nerves. CONCLUSIONS: Decreased corneal nerves and abnormal nerve conduction were found in children with type 1 diabetes. CCM may allow rapid objective detection of subclinical diabetic neuropathy in children and adolescents with type 1 diabetes.
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Carmichael J, Fadavi H, Ishibashi F, Howard S, Boulton AJM, Shore AC, Tavakoli M (2022). Implementation of corneal confocal microscopy for screening and early detection of diabetic neuropathy in primary care alongside retinopathy screening: Results from a feasibility study.
Frontiers in Endocrinology,
13Abstract:
Implementation of corneal confocal microscopy for screening and early detection of diabetic neuropathy in primary care alongside retinopathy screening: Results from a feasibility study
Objective: Screening for diabetic peripheral neuropathy (DPN) is essential for early detection and timely intervention. Quantitative assessment of small nerve fiber damage is key to the early diagnosis and assessment of its progression. Corneal confocal microscopy (CCM) is a non-invasive, in-vivo diagnostic technique that provides an accurate surrogate biomarker for small-fiber neuropathy. In this novel study for the first time, we introduced CCM to primary care as a screening tool for DPN alongside retinopathy screening to assess the level of neuropathy in this novel cohort. Research design and methods: 450 consecutive subjects with type 1 or type 2 diabetes attending for annual eye screening in primary care optometry settings underwent assessment with CCM to establish the prevalence of sub-clinical diabetic peripheral neuropathy. Subjects underwent assessment for neurological and ocular symptoms of diabetes and a history of diabetic foot disease, neuropathy and diabetic retinopathy (DR). Results: CCM examination was completed successfully in 427 (94.9%) subjects, 22% of whom had neuropathy according to Diabetic Neuropathy Symptom (DNS) score. The prevalence of sub-clinical neuropathy as defined by abnormal corneal nerve fiber length (CNFL) was 12.9%. In the subjects with a short duration of type 2 diabetes, 9.2% had abnormal CNFL. CCM showed significant abnormalities in corneal nerve parameters in this cohort of subjects with reduction of corneal nerve fiber density (CNFD, p
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Ishibashi F, Kosaka A, Tavakoli M (2022). Sodium Glucose Cotransporter-2 Inhibitor Protects Against Diabetic Neuropathy and Nephropathy in Modestly Controlled Type 2 Diabetes: Follow-Up Study. Frontiers in Endocrinology, 13
Carmichael J, Fadavi H, Ishibashi F, Shore AC, Tavakoli M (2021). Advances in Screening, Early Diagnosis and Accurate Staging of Diabetic Neuropathy.
FRONTIERS IN ENDOCRINOLOGY,
12 Author URL.
Tavakoli M, Petropoulos IN, Malik RA (2021). Assessing corneal nerve structure and function in diabetic neuropathy. Clinical and Experimental Optometry, 95(3), 338-347.
Perkins BA, Lovblom LE, Lewis EJH, Bril V, Ferdousi M, Orszag A, Edwards K, Pritchard N, Russell A, Dehghani C, et al (2021). Corneal Confocal Microscopy Predicts the Development of Diabetic Neuropathy: a Longitudinal Diagnostic Multinational Consortium Study.
Diabetes Care,
44(9), 2107-2114.
Abstract:
Corneal Confocal Microscopy Predicts the Development of Diabetic Neuropathy: a Longitudinal Diagnostic Multinational Consortium Study.
OBJECTIVE: Corneal nerve fiber length (CNFL) has been shown in research studies to identify diabetic peripheral neuropathy (DPN). In this longitudinal diagnostic study, we assessed the ability of CNFL to predict the development of DPN. RESEARCH DESIGN AND METHODS: from a multinational cohort of 998 participants with type 1 and type 2 diabetes, we studied the subset of 261 participants who were free of DPN at baseline and completed at least 4 years of follow-up for incident DPN. The predictive validity of CNFL for the development of DPN was determined using time-dependent receiver operating characteristic (ROC) curves. RESULTS: a total of 203 participants had type 1 and 58 had type 2 diabetes. Mean follow-up time was 5.8 years (interquartile range 4.2-7.0). New-onset DPN occurred in 60 participants (23%; 4.29 events per 100 person-years). Participants who developed DPN were older and had a higher prevalence of type 2 diabetes, higher BMI, and longer duration of diabetes. The baseline electrophysiology and corneal confocal microscopy parameters were in the normal range but were all significantly lower in participants who developed DPN. The time-dependent area under the ROC curve for CNFL ranged between 0.61 and 0.69 for years 1-5 and was 0.80 at year 6. The optimal diagnostic threshold for a baseline CNFL of 14.1 mm/mm2 was associated with 67% sensitivity, 71% specificity, and a hazard ratio of 2.95 (95% CI 1.70-5.11; P < 0.001) for new-onset DPN. CONCLUSIONS: CNFL showed good predictive validity for identifying patients at higher risk of developing DPN ∼6 years in the future.
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Celiker H, Erekul G, Turhan SA, Kokar S, Yavuz DG, Gunduz OH, Tavakoli M, Toker E (2021). Early detection of neuropathy in patients with type 2 diabetes with or without microalbuminuria in the absence of peripheral neuropathy and retinopathy.
J Fr Ophtalmol,
44(4), 485-493.
Abstract:
Early detection of neuropathy in patients with type 2 diabetes with or without microalbuminuria in the absence of peripheral neuropathy and retinopathy.
PURPOSE: Our goal is early detection of neuropathy in patients with type 2 diabetes with or without microalbuminuria in the absence of diabetic retinopathy and peripheral neuropathy by using in vivo corneal confocal microscopy (IVCCM). METHODS: a total of 60 type-2 diabetic patients, assigned to either a diabetes mellitus (DM) with microalbuminuria group (DM/MA+, n=30) or a DM without microalbuminuria group (DM/MA-, n=30), and 30 age-matched control subjects were enrolled in this study. All cases underwent evaluation of blood glucose level, HbA1c, lipid fractions, body mass index (BMI), and corneal sensitivity (CS). Corneal nerve fiber length (NFL), nerve fiber density (NFD), nerve branch density (NBD), and tortuosity coefficient (TC) were quantified by IVCCM. None of the patients had peripheral neuropathy or retinopathy. RESULTS: Compared with the healthy subjects, NFL and NFD were reduced in both diabetic groups (P
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Ando A, Miyamoto M, Saito N, Kotani K, Kamiya H, Ishibashi S, Tavakoli M (2021). Small Fibre Neuropathy is Associated with Impaired Vascular Endothelial Function in Patients with Type 2 Diabetes.
Frontiers in Endocrinology,
12Abstract:
Small Fibre Neuropathy is Associated with Impaired Vascular Endothelial Function in Patients with Type 2 Diabetes
Diabetic polyneuropathy (DPN) and endothelial dysfunction are prevalent complications of diabetes mellitus. Currently, there are two non-invasive markers for endothelial dysfunction: flow-mediated dilation and reactive hyperaemia peripheral arterial tonometry (RH-PAT). However, the relationship between diabetic small fibre neuropathy and macroangiopathy remains obscure thus far. Corneal confocal microscopy (CCM) has emerged as a new diagnostic modality to assess DPN, especially of small fibre. To clarify the relationship between diabetic small fibre neuropathy and vascular dysfunction, we aimed to determine the functions of peripheral nerves and blood vessels through clinical tests such as nerve conduction study, coefficient of variation in the R-R interval, CCM, and RH-PAT in 82 patients with type 2 diabetes. Forty healthy control subjects were also included to study corneal nerve parameters. Correlational and multiple linear regression analyses were performed to determine the associations between neuropathy indices and markers for vascular functions. The results revealed that patients with type 2 diabetes had significantly lower values for most variables of CCM than healthy control subjects. RH-PAT solely remained as an explanatory variable significant in multiple regression analysis for several CCM parameters and vice versa. Other vascular markers had no significant multiple regression with any CCM parameters. In conclusion, endothelial dysfunction as revealed by impaired RH-PAT was significantly associated with CCM parameters in patients with type 2 diabetes. This association may indicate that small fibre neuropathy results from impaired endothelial dysfunction in type 2 diabetes. CCM parameters may be considered surrogate markers of autonomic nerve damage, which is related to diabetic endothelial dysfunction. This study is the first to report the relationship between corneal nerve parameter as small fibre neuropathy in patients with type 2 diabetes and RH-PAT as a marker of endothelial dysfunction.
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Ishibashi F, Kosaka A, Tavakoli M (2021). The Impact of Glycemic Control on Retinal Photoreceptor Layers and Retinal Pigment Epithelium in Patients with Type 2 Diabetes Without Diabetic Retinopathy: a Follow-Up Study.
Frontiers in Endocrinology,
12Abstract:
The Impact of Glycemic Control on Retinal Photoreceptor Layers and Retinal Pigment Epithelium in Patients with Type 2 Diabetes Without Diabetic Retinopathy: a Follow-Up Study
AimsTo establish the sequential changes by glycemic control in the mean thickness, volume and reflectance of the macular photoreceptor layers (MPRLs) and retinal pigment epithelium in patients with type 2 diabetes without diabetic retinopathy.MethodsThirty-one poorly controlled (HbA1c &gt; 8.0%) patients with type 2 diabetes without diabetic retinopathy undergoing glycemic control and 39 control subjects with normal HbA1c levels (&lt; 5.9%) underwent periodical full medical, neurological and ophthalmological examinations over 2 years. Glycemic variability was evaluated by standard deviation and coefficient of variation of monthly measured HbA1c levels and casual plasma glucose. 3D swept source-optical coherence tomography (OCT) and OCT-Explorer-generated enface thickness, volume and reflectance images for 9 subfields defined by Early Treatment Diabetic Retinopathy Study of 4 MPRLs {outer nuclear layer, ellipsoid zone, photoreceptor outer segment (PROS) and interdigitation zone} and retinal pigment epithelium were acquired every 3 months.ResultsGlycemic control sequentially restored the thickness and volume at 6, 4 and 5 subfields of outer nuclear layer, ellipsoid zone and PROS, respectively. The thickness and volume of outer nuclear layer were restored related to the decrease in HbA1c and casual plasma glucose levels, but not related to glycemic variability and neurological tests. The reflectance of MPRLs and retinal pigment epithelium in patients was marginally weaker than controls, and further decreased at 6 or 15 months during glycemic control. The reduction at 6 months coincided with high HbA1c levels.ConclusionGlycemic control sequentially restored the some MPRL thickness, especially of outer nuclear layer. In contrast, high glucose during glycemic control decreased reflectance and may lead to the development of diabetic retinopathy induced by glycemic control. The repeated OCT examinations can clarify the benefit and hazard of glycemic control to the diabetic retinopathy.
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Lewis EJH, Lovblom LE, Ferdousi M, Halpern EM, Jeziorska M, Pacaud D, Pritchard N, Dehghani C, Edwards K, Srinivasan S, et al (2020). Rapid Corneal Nerve Fiber Loss: a Marker of Diabetic Neuropathy Onset and Progression.
Diabetes Care,
43(8), 1829-1835.
Abstract:
Rapid Corneal Nerve Fiber Loss: a Marker of Diabetic Neuropathy Onset and Progression
. OBJECTIVE
. Corneal nerve fiber length (CNFL) represents a biomarker for diabetic distal symmetric polyneuropathy (DSP). We aimed to determine the reference distribution of annual CNFL change, the prevalence of abnormal change in diabetes, and its associated clinical variables.
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. RESEARCH DESIGN AND METHODS
. We examined 590 participants with diabetes (399 with type 1 diabetes [T1D] and 191 with type 2 diabetes [T2D]) and 204 control patients without diabetes with at least 1 year of follow-up and classified them according to rapid corneal nerve fiber loss (RCNFL) if CNFL change was below the 5th percentile of the control patients without diabetes.
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. RESULTS
. Control patients without diabetes were 37.9 ± 19.8 years old, had median follow-up of three visits over 3.0 years, and mean annual change in CNFL was −0.1% (90% CI −5.9% to 5.0%). RCNFL was defined by values exceeding the 5th percentile of 6% loss. Participants with T1D were 39.9 ± 18.7 years old, had median follow-up of three visits over 4.4 years, and mean annual change in CNFL was −0.8% (90% CI −14.0% to 9.9%). Participants with T2D were 60.4 ± 8.2 years old, had median follow-up of three visits over 5.3 years, and mean annual change in CNFL was −0.2% (90% CI −14.1% to 14.3%). RCNFL prevalence was 17% overall and was similar by diabetes type (64 T1D [16.0%], 37 T2D [19.4%], P = 0.31). RNCFL was more common in those with baseline DSP (47% vs. 30% in those without baseline DSP, P = 0.001), which was associated with lower peroneal conduction velocity but not with baseline HbA1c or its change over follow-up.
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. CONCLUSIONS
. An abnormally rapid loss of CNFL of 6% per year or more occurs in 17% of diabetes patients. RCNFL may identify patients at highest risk for the development and progression of DSP.
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Ishibashi F, Tavakoli M (2020). Thinning of Macular Neuroretinal Layers Contributes to Sleep Disorder in Patients with Type 2 Diabetes Without Clinical Evidences of Neuropathy and Retinopathy. Frontiers in Endocrinology, 11
Ishibashi F, Taniguchi M, Kosaka A, Uetake H, Tavakoli M (2019). Improvement in Neuropathy Outcomes with Normalizing HbA1c in Patients with Type 2 Diabetes.
Diabetes Care,
42(1), 110-118.
Abstract:
Improvement in Neuropathy Outcomes with Normalizing HbA1c in Patients with Type 2 Diabetes.
OBJECTIVE: to investigate the impact of normalizing HbA1c by extensive HbA1c control (EHC) on neuropathy outcome measures (NOMs), nephropathy, and retinopathy in type 2 diabetes. RESEARCH DESIGN AND METHODS: Detailed clinical and neurological examinations were performed in two cohorts of 38 patients with uncontrolled type 2 diabetes (HbA1c 9.6% [81.4 mmol/mol]) at baseline and after glycemic control (GC) with or without EHC by diet restriction and hypoglycemic agents over 4 years along with 48 control subjects with normal glucose tolerance (NGT) and 34 subjects with impaired glucose tolerance (IGT) only at baseline. EHC patients, control subjects, and subjects with IGT underwent oral glucose tolerance tests. Glycemic variability (GV) was evaluated by SD and coefficient of variation of monthly measured HbA1c levels and casual plasma glucose. RESULTS: in the EHC cohort, HbA1c levels over 4.3 years and the last 2 years improved to 6.1% (43.2 mmol/mol) and 5.8% (39.9 mmol/mol) with 7.3 kg body wt reduction, and 50% and 28.9% of patients returned to IGT and NGT, respectively, at end point. Baseline neurophysiological and corneal nerve fiber (CNF) measures were impaired in patients. Normalized HbA1c with EHC improved neurophysiological and CNF measures to be similar for those for IGT, while GC without EHC (mean HbA1c level 7.0% [53.5 mmol/mol]) improved only vibration perception. The mean normalized HbA1c levels by EHC determined NOM improvements. The high GV and baseline HbA1c levels compromised NOMs. Albumin excretion rate significantly decreased, while retinopathy severity and frequency insignificantly worsened on EHC. CONCLUSIONS: Normalizing HbA1c in type 2 diabetes of short duration improves microvascular complications including neuropathy and nephropathy more effectively than standard GC but not retinopathy.
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Lewis EJ, Tavakoli M, Lovblom LE, Halpern EM, Jeziorska M, Pacaud D, Pritchard N, Shtein RM, Efron N, Bril V, et al (2018). 26 the Reference Distribution of Annual Change in Corneal Nerve Fibre Length in Diabetes. Canadian Journal of Diabetes, 42(5).
Perkins BA, Lovblom LE, Bril V, Scarr D, Ostrovski I, Orszag A, Edwards K, Pritchard N, Russell A, Dehghani C, et al (2018). Corneal confocal microscopy for identification of diabetic sensorimotor polyneuropathy: a pooled multinational consortium study.
Diabetologia,
61(8), 1856-1861.
Abstract:
Corneal confocal microscopy for identification of diabetic sensorimotor polyneuropathy: a pooled multinational consortium study
Aims/hypothesis: Small cohort studies raise the hypothesis that corneal nerve abnormalities (including corneal nerve fibre length [CNFL]) are valid non-invasive imaging endpoints for diabetic sensorimotor polyneuropathy (DSP). We aimed to establish concurrent validity and diagnostic thresholds in a large cohort of participants with and without DSP. Methods: Nine hundred and ninety-eight participants from five centres (516 with type 1 diabetes and 482 with type 2 diabetes) underwent CNFL quantification and clinical and electrophysiological examination. AUC and diagnostic thresholds were derived and validated in randomly selected samples using receiver operating characteristic analysis. Sensitivity analyses included latent class models to address the issue of imperfect reference standard. Results: Type 1 and type 2 diabetes subcohorts had mean age of 42 ± 19 and 62 ± 10 years, diabetes duration 21 ± 15 and 12 ± 9 years and DSP prevalence of 31% and 53%, respectively. Derivation AUC for CNFL was 0.77 in type 1 diabetes (p < 0.001) and 0.68 in type 2 diabetes (p < 0.001) and was approximately reproduced in validation sets. The optimal threshold for automated CNFL was 12.5 mm/mm2 in type 1 diabetes and 12.3 mm/mm2 in type 2 diabetes. In the total cohort, a lower threshold value below 8.6 mm/mm2 to rule in DSP and an upper value of 15.3 mm/mm2 to rule out DSP were associated with 88% specificity and 88% sensitivity. Conclusions/interpretation: We established the diagnostic validity and common diagnostic thresholds for CNFL in type 1 and type 2 diabetes. Further research must determine to what extent CNFL can be deployed in clinical practice and in clinical trials assessing the efficacy of disease-modifying therapies for DSP.
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Fadavi H, Tavakoli M, Foden P, Ferdousi M, Petropoulos IN, Jeziorska M, Chaturvedi N, Boulton AJM, Malik RA, Abbott CA, et al (2018). Explanations for less small fibre neuropathy in South Asian versus European subjects with type 2 diabetes in the UK.
Diabetes Metab Res Rev,
34(7).
Abstract:
Explanations for less small fibre neuropathy in South Asian versus European subjects with type 2 diabetes in the UK.
BACKGROUND: Low foot ulcer risk in South Asian, compared with European, people with type 2 diabetes in the UK has been attributed to their lower levels of neuropathy. We have undertaken a detailed study of corneal nerve morphology and neuropathy risk factors, to establish the basis of preserved small nerve fibre function in South Asians versus Europeans. METHODS: in a cross-sectional, population-based study, age- and sex-matched South Asians (n = 77) and Europeans (n = 78) with type 2 diabetes underwent neuropathy assessment using corneal confocal microscopy, symptoms, signs, quantitative sensory testing, electrophysiology and autonomic function testing. Multivariable linear regression analyses determined factors accounting for ethnic differences in small fibre damage. RESULTS: Corneal nerve fibre length (22.0 ± 7.9 vs. 19.3 ± 6.3 mm/mm2 ; P = 0.037), corneal nerve branch density (geometric mean (range): 60.0 (4.7-246.2) vs. 46.0 (3.1-129.2) no./mm2 ; P = 0.021) and heart rate variability (geometric mean (range): 7.9 (1.4-27.7) vs. 6.5 (1.5-22.0); P = 0.044), were significantly higher in South Asians vs. Europeans. All other neuropathy measures did not differ, except for better sural nerve amplitude in South Asians (geometric mean (range): 10.0 (1.3-43.0) vs. 7.2 (1.0-30.0); P = 0.006). Variables with the greatest impact on attenuating the P value for age- and HbA1C -adjusted ethnic difference in corneal nerve fibre length (P = 0.032) were pack-years smoked (P = 0.13), BMI (P = 0.062) and triglyceride levels (P = 0.062). CONCLUSIONS: South Asians have better preserved small nerve fibre integrity than equivalent Europeans; furthermore, classic, modifiable risk factors for coronary heart disease are the main contributors to these ethnic differences. We suggest that improved autonomic neurogenic control of cutaneous blood flow in Asians may contribute to their protection against foot ulcers.
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Ishibashi F, Tavakoli M (2018). Impact of normoglycemia in reducing microvascular complications in patients with type 2 diabetes: a follow-up study.
Frontiers in Endocrinology,
9(MAR).
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Impact of normoglycemia in reducing microvascular complications in patients with type 2 diabetes: a follow-up study
Aims: Hyperglycemia is associated with an increased risk of microvascular complications in patients with type 2 diabetes. The aim of the present study was to investigate whether the reduction of the levels of HbA1c by tight glycemic control (GC) decreases the rate of microvascular complications and improves the neurological measures in patients with type 2 diabetes. Methods: Detailed clinical and neurological examinations including corneal confocal microscopy (CCM) were performed in 141 Japanese patients with type 2 diabetes and 60 age-matched control subjects at baseline and follow-up with GC for 4 years. Patients were stratified according to the mean HbA1c level during follow-up into good (HbA1c < 53.0 mmol/mol, mean; 47.5 mmol/mol), fair (53.0 mmol/mol ≤ HbA1c < 58.5 mmol/mol, mean; 55.6 mmol/mol), and poor (HbA1c ≥ 58.5 mmol/mol, mean; 68.9 mmol/mol) GC groups with similar HbA1c levels at baseline (84.5-88.2 mmol/mol). Results: at baseline, CCM revealed significant nerve fiber damage in all patients compared to that in controls. The interval changes in most corneal nerve fiber (CNF) parameters and neurophysiological functions were significantly related with the mean HbA1c levels during follow-up. Interestingly, the baseline HbA1c level did not impact on neurological functions at follow-up. Interval changes in neuropathy outcomes were associated with mean clinical factors during follow-up and hypoglycemic strategies. Good GC improved all nerve functions, including CNF branch density and bead, but not the length and main fiber density. Fair GC deteriorated some nerve functions. Poor GC compromised all neuropathy outcomes. Irrespective of GC levels, retinopathy increased after follow-up period, while nephropathy decreased. Conclusion: This study showed that tight GC was beneficial just for nephropathy among microvascular complications. Despite strict GC, the retinopathy progressed in patients with type 2 diabetes. Glucose control did not improve neurophysiological and corneal nerve measurements unless near-normoglycemia was reached.
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Tavakoli M, Yavuz DG, Tahrani AA, Selvarajah D, Bowling FL, Fadavi H (2017). Diabetic Neuropathy: Current Status and Future Prospects.
JOURNAL OF DIABETES RESEARCH,
2017 Author URL.
Alam U, Jeziorska M, Petropoulos IN, Asghar O, Fadavi H, Ponirakis G, Marshall A, Tavakoli M, Boulton AJM, Efron N, et al (2017). Diagnostic utility of corneal confocal microscopy and intra-epidermal nerve fibre density in diabetic neuropathy.
PLoS One,
12(7).
Abstract:
Diagnostic utility of corneal confocal microscopy and intra-epidermal nerve fibre density in diabetic neuropathy.
OBJECTIVES: Corneal confocal microscopy (CCM) is a rapid, non-invasive, reproducible technique that quantifies small nerve fibres. We have compared the diagnostic capability of CCM against a range of established measures of nerve damage in patients with diabetic neuropathy. METHODS: in this cross sectional study, thirty subjects with Type 1 diabetes without neuropathy (T1DM), thirty one T1DM subjects with neuropathy (DSPN) and twenty seven non-diabetic healthy control subjects underwent detailed assessment of neuropathic symptoms and neurologic deficits, quantitative sensory testing (QST), electrophysiology, skin biopsy and corneal confocal microscopy (CCM). RESULTS: Subjects with DSPN were older (C vs T1DM vs DSPN: 41.0±14.9 vs 38.8±12.5 vs 53.3±11.9, P = 0.0002), had a longer duration of diabetes (P
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Alahmar AT, Petropoulos IN, Ferdousi M, Jones W, Fadavi H, Azmi S, Alam U, Asghar O, Meskiri A, Kheyami A, et al (2017). Expression of skin Glyoxalase-I, advanced glycation end products (AGEs) and receptor (RAGE) in patients with long term type 1 diabetes and diabetic neuropathy.
Brunei International Medical Journal,
13(6), 180-193.
Abstract:
Expression of skin Glyoxalase-I, advanced glycation end products (AGEs) and receptor (RAGE) in patients with long term type 1 diabetes and diabetic neuropathy
Background: Certain group of diabetic patients have been shown to remain free of diabetic complications despite having had diabetes for longer periods. Advanced glycation end products (AGEs), their receptor (RAGE) and Glyoxalase-I (GLO-I) have been implicated in the development of diabetic neuropathy. Objective: to assess the effect of long term type 1 diabetes mellitus on skin distribution and expression of AGEs, RAGE and GLO-I and to correlate these expressions with measures of small and large nerve fibre damage. Methods: Sixty-seven patients with type 1 diabetes mellitus of shorter ( < 15 years, n=20), intermediate (15-40 years, n=25) and longer ( > 40 years, n=22) duration and 34 non-diabetic controls underwent diabetic neuropathy assessment: Neuropathy disability score (NDS), quantitative sensory testing (QST) including vibration pressure and thermal thresholds, nerve conduction studies (NCS), deep breathing heart rate variability (DB-HRV), corneal confocal microscopy (CCM) and intraepidermal nerve fibre density (IENFD) and AGEs, RAGE and GLO-I expression in foot skin biopsies. Results: Compared to controls, type 1 diabetes mellitus patients showed progressively increased skin expression of AGEs, RAGE but progressively lower GLO-I expression with increasing duration of diabetes. Thus patients with longerduration diabetes demonstrated significantly higher skin AGEs and RAGE but lower GLO-I expression than both shorter and intermediate duration diabetic groups. In patients with longer duration diabetes who developed diabetic neuropathy, the skin expression of AGEs and RAGE were significantly higher but GLO-I were significantly lower than those who did not develop diabetic neuropathy. These expressions also correlated with IENFD, CCM and NCS measures. Conclusion: Patients with type 1 diabetes mellitus showed progressively increased skin expression of AGEs, RAGE but progressively lower GLO-I expression with increasing duration of diabetes. Patients with longer duration diabetes who developed diabetic neuropathy have significantly higher skin AGEs and RAGE and decreased GLO-I expression suggesting a potential role for these macromolecules as aetiological, marker of the disease as well as therapeutic target for diabetic neuropathy.
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Kapetis D, Sassone J, Yang Y, Galbardi B, Xenakis MN, Westra RL, Szklarczyk R, Lindsey P, Faber CG, Gerrits M, et al (2017). Network topology of NaV1.7 mutations in sodium channel-related painful disorders. BMC Systems Biology, 11(1).
Azmi S, Ferdousi M, Alam U, Petropoulos IN, Ponirakis G, Marshall A, Asghar O, Fadavi H, Jones W, Tavakoli M, et al (2017). Small-fibre neuropathy in men with type 1 diabetes and erectile dysfunction: a cross-sectional study.
Diabetologia,
60(6), 1094-1101.
Abstract:
Small-fibre neuropathy in men with type 1 diabetes and erectile dysfunction: a cross-sectional study.
AIMS/HYPOTHESIS: the aim of this study was to identify the contribution of small- and large-fibre neuropathy to erectile dysfunction in men with type 1 diabetes mellitus. METHODS: a total of 70 participants (29 without and 41 with erectile dysfunction) with type 1 diabetes and 34 age-matched control participants underwent a comprehensive assessment of large- and small-fibre neuropathy. RESULTS: the prevalence of erectile dysfunction in participants with type 1 diabetes was 58.6%. After adjusting for age, participants with type 1 diabetes and erectile dysfunction had a significantly higher score on the Neuropathy Symptom Profile (mean ± SEM 5.3 ± 0.9 vs 1.8 ± 1.2, p = 0.03), a higher vibration perception threshold (18.3 ± 1.9 vs 10.7 ± 2.4 V, p = 0.02), and a lower sural nerve amplitude (5.0 ± 1.1 vs 11.7 ± 1.5 mV, p = 0.002), peroneal nerve amplitude (2.1 ± 0.4 vs 4.7 ± 0.5 mV, p
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Marshall AG, Lee-Kubli C, Azmi S, Zhang M, Ferdousi M, Mixcoatl-Zecuatl T, Petropoulos IN, Ponirakis G, Fineman MS, Fadavi H, et al (2017). Spinal Disinhibition in Experimental and Clinical Painful Diabetic Neuropathy.
Diabetes,
66(5), 1380-1390.
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Spinal Disinhibition in Experimental and Clinical Painful Diabetic Neuropathy.
Impaired rate-dependent depression (RDD) of the Hoffman reflex is associated with reduced dorsal spinal cord potassium chloride cotransporter expression and impaired spinal γ-aminobutyric acid type a receptor function, indicative of spinal inhibitory dysfunction. We have investigated the pathogenesis of impaired RDD in diabetic rodents exhibiting features of painful neuropathy and the translational potential of this marker of spinal inhibitory dysfunction in human painful diabetic neuropathy. Impaired RDD and allodynia were present in type 1 and type 2 diabetic rats but not in rats with type 1 diabetes receiving insulin supplementation that did not restore normoglycemia. Impaired RDD in diabetic rats was rapidly normalized by spinal delivery of duloxetine acting via 5-hydroxytryptamine type 2A receptors and temporally coincident with the alleviation of allodynia. Deficits in RDD and corneal nerve density were demonstrated in patients with painful diabetic neuropathy compared with healthy control subjects and patients with painless diabetic neuropathy. Spinal inhibitory dysfunction and peripheral small fiber pathology may contribute to the clinical phenotype in painful diabetic neuropathy. Deficits in RDD may help identify patients with spinally mediated painful diabetic neuropathy who may respond optimally to therapies such as duloxetine.
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Tavakoli M, Fukashi Ishibashi, Rie Kojima, Miki Taniguchi, Aiko Kosaka, Harumi Uetake, Mitra Tavakoli (2017). The Preferential Impairment of Pupil Constriction Stimulated by Blue Light in Patients with Type 2 Diabetes without Autonomic Neuropathy. Journal of Diabetes Research
Perkins BA, Lovblom LE, Bril V, Edwards K, Pritchard N, Russell A, Pacaud D, Romanchuk K, Mah J, Boulton A, et al (2016). 209 Results of an International Corneal Confocal Microscopy (CCM) Consortium: a Pooled Multicentre Analysis of the Concurrent Diagnostic Validity of CCM to Identify Diabetic Polyneuropathy in Type 2 Diabetes Mellitus. Canadian Journal of Diabetes, 40(5).
Perkins BA, Lovblom LE, Bril V, Edwards K, Pritchard N, Russell A, Pacaud D, Romanchuk K, Mah J, Boulton A, et al (2016). 59 Results of an International Corneal Confocal Microscopy (CCM) Consortium: a Pooled Multicentre Analysis of the Concurrent Diagnostic Validity of CCM to Identify Diabetic Polyneuropathy in Type 1 Diabetes Mellitus. Canadian Journal of Diabetes, 40(5).
Tavakoli M, Chen X, Graham J, Petropoulos I, Malik R (2016). An Automatic Tool for Quantification of Nerve Fibres in Corneal Confocal Microscopy Images. IEEE Trans Biomed Eng, 64, 786-794.
Ponirakis G, Odriozola MN, Odriozola S, Petropoulos IN, Azmi S, Ferdousi M, Fadavi H, Alam U, Marshall A, Jeziorska M, et al (2016). NerveCheck for the Detection of Sensory Loss and Neuropathic Pain in Diabetes.
Diabetes Technol Ther,
18(12), 800-805.
Abstract:
NerveCheck for the Detection of Sensory Loss and Neuropathic Pain in Diabetes.
BACKGROUND: Accurate and economic detection of nerve damage in diabetes is key to more widespread diagnosis of patients with diabetic peripheral neuropathy (DPN) and painful diabetic neuropathy. This study examined the diagnostic performance of NerveCheck, an inexpensive ($500) quantitative sensory testing (QST) device. METHODS: One hundred forty-four subjects (74 with and 70 without diabetes) underwent assessment with NerveCheck, neuropathy disability score (NDS), nerve conduction studies (NCS), intraepidermal and corneal nerve fiber density (IENFD and CNFD), and McGill questionnaire for neuropathic pain. RESULTS: of the 74 subjects with diabetes, 41 were diagnosed with DPN based on the NDS. The NerveCheck scores for vibration perception threshold (VPT), cold perception threshold (CPT), and warm perception threshold (WPT) were significantly lower (P ≤ 0.0001) in diabetic patients with DPN compared to patients without DPN. The diagnostic accuracy of VPT was high with reference to NCS (area under the curve [AUC]: 82%-84%) and moderate for IENFD, CNFD, and neuropathic pain (AUC: 60%-76%). The diagnostic accuracy of CPT and WPT was moderate with reference to NCS, IENFD, and CNFD (AUC: 69%-78%) and low for neuropathic pain (AUC: 63%-65%). CONCLUSIONS: NerveCheck is a low-cost QST device with good diagnostic utility for identifying sensory deficits, comparable to established tests of large and small fiber neuropathy and for the severity of neuropathic pain.
Abstract.
Author URL.
Perini I, Tavakoli M, Marshall A, Minde J, Morrison I (2016). Rare human nerve growth factor-β mutation reveals relationship between C-afferent density and acute pain evaluation.
J Neurophysiol,
116(2), 425-430.
Abstract:
Rare human nerve growth factor-β mutation reveals relationship between C-afferent density and acute pain evaluation.
The rare nerve growth factor-β (NGFB) mutation R221W causes a selective loss of thinly myelinated fibers and especially unmyelinated C-fibers. Carriers of this mutation show altered pain sensation. A subset presents with arthropathic symptoms, with the homozygous most severely affected. The aim of the present study was to investigate the relationship between peripheral afferent loss and pain evaluation by performing a quantification of small-fiber density in the cornea of the carriers, relating density to pain evaluation measures. In vivo corneal confocal microscopy (CCM) was used to quantify C-fiber loss in the cornea of 19 R221W mutation carriers (3 homozygous) and 19 age-matched healthy control subjects. Pain evaluation data via the Situational Pain Questionnaire (SPQ) and the severity of neuropathy based on the Neuropathy Disability Score (NDS) were assessed. Homozygotes, heterozygotes, and control groups differed significantly in corneal C-nerve fiber density, with the homozygotes showing a significant afferent reduction. Importantly, peripheral C-fiber loss correlated negatively with pain evaluation, as revealed by SPQ scores. This study is the first to investigate the contribution of small-fiber density to the perceptual evaluation of pain. It demonstrates that the lower the peripheral small-fiber density, the lower the degree of reported pain intensity, indicating a functional relationship between small-fiber density and higher level pain experience.
Abstract.
Author URL.
Alahmar A, Petropoulos I, Ferdousi M, Jones W, Fadavi H, Azmi S, Alam U, Asghar O, Meskiri A, Kheyami A, et al (2016). Skin Expression of Advanced Glycation end Products (AGEs), Their Receptor (RAGE) and Glyoxalase-I (GLO-I) in Patients with Diabetic Neuropathy. British Journal of Medicine and Medical Research, 12(5), 1-13.
Ishibashi F, Kojima R, Taniguchi M, Kosaka A, Uetake H, Tavakoli M (2016). The Expanded Bead Size of Corneal C-Nerve Fibers Visualized by Corneal Confocal Microscopy is Associated with Slow Conduction Velocity of the Peripheral Nerves in Patients with Type 2 Diabetes Mellitus.
J Diabetes Res,
2016Abstract:
The Expanded Bead Size of Corneal C-Nerve Fibers Visualized by Corneal Confocal Microscopy is Associated with Slow Conduction Velocity of the Peripheral Nerves in Patients with Type 2 Diabetes Mellitus.
This study aims to establish the corneal nerve fiber (CNF) morphological alterations in a large cohort of type 2 diabetic patients and to investigate the association between the bead size, a novel parameter representing composite of accumulated mitochondria, glycogen particles, and vesicles in CNF, and the neurophysiological dysfunctions of the peripheral nerves. 162 type 2 diabetic patients and 45 healthy control subjects were studied in detail with a battery of clinical and neurological examinations and corneal confocal microscopy. Compared with controls, patients had abnormal CNF parameters. In particular the patients had reduced density and length of CNF and beading frequency and increased bead size. Alterations in CNF parameters were significant even in patients without neuropathy. The HbA1c levels were tightly associated with the bead size, which was inversely related to the motor and sensory nerve conduction velocity (NCV) and to the distal latency period of the median nerve positively. The CNF density and length positively correlated with the NCV and amplitude. The hyperglycemia-induced expansion of beads in CNF might be a predictor of slow NCV in peripheral nerves in type 2 diabetic patients.
Abstract.
Author URL.
Tavakoli M, Malik R (2015). 8. The Acceptability and Feasibility of Corneal Confocal Microscopy to Detect Diabetic Neuropathy in Children: a Pilot Study (632-P). Nederlands Tijdschrift voor Diabetologie, 13(3), 61-62.
Ponirakis G, Fadavi H, Petropoulos IN, Azmi S, Ferdousi M, Dabbah MA, Kheyami A, Alam U, Asghar O, Marshall A, et al (2015). Automated Quantification of Neuropad Improves its Diagnostic Ability in Patients with Diabetic Neuropathy.
Journal of Diabetes Research,
2015, 1-7.
Abstract:
Automated Quantification of Neuropad Improves its Diagnostic Ability in Patients with Diabetic Neuropathy
Neuropad is currently a categorical visual screening test that identifies diabetic patients at risk of foot ulceration. The diagnostic performance of Neuropad was compared between the categorical and continuous (image-analysis (Sudometrics)) outputs to diagnose diabetic peripheral neuropathy (DPN). 110 subjects with type 1 and 2 diabetes underwent assessment with Neuropad, Neuropathy Disability Score (NDS), peroneal motor nerve conduction velocity (PMNCV), sural nerve action potential (SNAP), Deep Breathing-Heart Rate Variability (DB-HRV), intraepidermal nerve fibre density (IENFD), and corneal confocal microscopy (CCM). 46/110 patients had DPN according to the Toronto consensus. The continuous output displayed high sensitivity and specificity for DB-HRV (91%, 83%), CNFD (88%, 78%), and SNAP (88%, 83%), whereas the categorical output showed high sensitivity but low specificity. The optimal cut-off points were 90% for the detection of autonomic dysfunction (DB-HRV) and 80% for small fibre neuropathy (CNFD). The diagnostic efficacy of the continuous Neuropad output for abnormal DB-HRV (AUC: 91%,P=0.0003) and CNFD (AUC: 82%,P=0.01) was better than for PMNCV (AUC: 60%). The categorical output showed no significant difference in diagnostic efficacy for these same measures. An image analysis algorithm generating a continuous output (Sudometrics) improved the diagnostic ability of Neuropad, particularly in detecting autonomic and small fibre neuropathy.
Abstract.
Bagheri A, Borhani M, Salehirad S, Yazdani S, Tavakoli M (2015). Blepharoptosis Associated with Third Cranial Nerve Palsy. Ophthalmic Plastic & Reconstructive Surgery, 31(5), 357-360.
Petropoulos IN, Green P, Chan AWS, Alam U, Fadavi H, Marshall A, Asghar O, Efron N, Tavakoli M, Malik RA, et al (2015). Corneal Confocal Microscopy Detects Neuropathy in Patients with Type 1 Diabetes without Retinopathy or Microalbuminuria. PLOS ONE, 10(4), e0123517-e0123517.
Ferdousi M, Azmi S, Petropoulos IN, Fadavi H, Ponirakis G, Marshall A, Tavakoli M, Malik I, Mansoor W, Malik RA, et al (2015). Corneal Confocal Microscopy Detects Small Fibre Neuropathy in Patients with Upper Gastrointestinal Cancer and Nerve Regeneration in Chemotherapy Induced Peripheral Neuropathy. PLOS ONE, 10(10), e0139394-e0139394.
Azmi S, Ferdousi M, Petropoulos IN, Ponirakis G, Alam U, Fadavi H, Asghar O, Marshall A, Atkinson AJ, Jones W, et al (2015). Corneal Confocal Microscopy Identifies Small-Fiber Neuropathy in Subjects with Impaired Glucose Tolerance Who Develop Type 2 Diabetes.
Diabetes Care,
38(8), 1502-1508.
Abstract:
Corneal Confocal Microscopy Identifies Small-Fiber Neuropathy in Subjects with Impaired Glucose Tolerance Who Develop Type 2 Diabetes
. OBJECTIVE
. Impaired glucose tolerance (IGT) through to type 2 diabetes is thought to confer a continuum of risk for neuropathy. Identification of subjects at high risk of developing type 2 diabetes and, hence, worsening neuropathy would allow identification and risk stratification for more aggressive management.
.
.
. RESEARCH DESIGN AND METHODS
. Thirty subjects with IGT and 17 age-matched control subjects underwent an oral glucose tolerance test, assessment of neuropathic symptoms and deficits, quantitative sensory testing, neurophysiology, skin biopsy, and corneal confocal microscopy (CCM) to quantify corneal nerve fiber density (CNFD), branch density (CNBD), and fiber length (CNFL) at baseline and annually for 3 years.
.
.
. RESULTS
. Ten subjects who developed type 2 diabetes had a significantly lower CNFD (P = 0.003), CNBD (P = 0.04), and CNFL (P = 0.04) compared with control subjects at baseline and a further reduction in CNFL (P = 0.006), intraepidermal nerve fiber density (IENFD) (P = 0.02), and mean dendritic length (MDL) (P = 0.02) over 3 years. Fifteen subjects who remained IGT and 5 subjects who returned to normal glucose tolerance had no significant baseline abnormality on CCM or IENFD but had a lower MDL (P &lt; 0.0001) compared with control subjects. The IGT subjects showed a significant decrease in IENFD (P = 0.02) but no change in MDL or CCM over 3 years. Those who returned to NGT showed an increase in CNFD (P = 0.05), CNBD (P = 0.04), and CNFL (P = 0.05), but a decrease in IENFD (P = 0.02), over 3 years.
.
.
. CONCLUSIONS
. CCM and skin biopsy detect a small-fiber neuropathy in subjects with IGT who develop type 2 diabetes and also show a dynamic worsening or improvement in corneal and intraepidermal nerve morphology in relation to change in glucose tolerance status.
.
Abstract.
Tavakoli M, Begum P, McLaughlin J, Malik RA (2015). Corneal confocal microscopy for the diagnosis of diabetic autonomic neuropathy. Muscle & Nerve, 52(3), 363-370.
Alam U, Asghar O, Petropoulos IN, Jeziorska M, Fadavi H, Ponirakis G, Marshall A, Tavakoli M, Boulton AJM, Efron N, et al (2015). Erratum. Small Fiber Neuropathy in Patients with Latent Autoimmune Diabetes in Adults. Diabetes Care 2015;38:e102–e103. Diabetes Care, 38(10), 1992.2-1992.
Lagali N, Poletti E, Patel DV, McGhee CNJ, Hamrah P, Kheirkhah A, Tavakoli M, Petropoulos IN, Malik RA, Utheim TP, et al (2015). Focused Tortuosity Definitions Based on Expert Clinical Assessment of Corneal Subbasal Nerves. Investigative Opthalmology & Visual Science, 56(9), 5102-5102.
Tavakoli M, Ferdousi M, Petropoulos IN, Morris J, Pritchard N, Zhivov A, Ziegler D, Pacaud D, Romanchuk K, Perkins BA, et al (2015). Normative Values for Corneal Nerve Morphology Assessed Using Corneal Confocal Microscopy: a Multinational Normative Data Set.
Diabetes Care,
38(5), 838-843.
Abstract:
Normative Values for Corneal Nerve Morphology Assessed Using Corneal Confocal Microscopy: a Multinational Normative Data Set
. OBJECTIVE
. Corneal confocal microscopy is a novel diagnostic technique for the detection of nerve damage and repair in a range of peripheral neuropathies, in particular diabetic neuropathy. Normative reference values are required to enable clinical translation and wider use of this technique. We have therefore undertaken a multicenter collaboration to provide worldwide age-adjusted normative values of corneal nerve fiber parameters.
.
.
. RESEARCH DESIGN AND METHODS
. A total of 1,965 corneal nerve images from 343 healthy volunteers were pooled from six clinical academic centers. All subjects underwent examination with the Heidelberg Retina Tomograph corneal confocal microscope. Images of the central corneal subbasal nerve plexus were acquired by each center using a standard protocol and analyzed by three trained examiners using manual tracing and semiautomated software (CCMetrics). Age trends were established using simple linear regression, and normative corneal nerve fiber density (CNFD), corneal nerve fiber branch density (CNBD), corneal nerve fiber length (CNFL), and corneal nerve fiber tortuosity (CNFT) reference values were calculated using quantile regression analysis.
.
.
. RESULTS
. There was a significant linear age-dependent decrease in CNFD (−0.164 no./mm2 per year for men, P &lt; 0.01, and −0.161 no./mm2 per year for women, P &lt; 0.01). There was no change with age in CNBD (0.192 no./mm2 per year for men, P = 0.26, and −0.050 no./mm2 per year for women, P = 0.78). CNFL decreased in men (−0.045 mm/mm2 per year, P = 0.07) and women (−0.060 mm/mm2 per year, P = 0.02). CNFT increased with age in men (0.044 per year, P &lt; 0.01) and women (0.046 per year, P &lt; 0.01). Height, weight, and BMI did not influence the 5th percentile normative values for any corneal nerve parameter.
.
.
. CONCLUSIONS
. This study provides robust worldwide normative reference values for corneal nerve parameters to be used in research and clinical practice in the study of diabetic and other peripheral neuropathies.
.
Abstract.
Petropoulos IN, Tavakoli M, Marshall A, Malik RA (2015). Response to Comment on Malik. Which Test for Diagnosing Early Human Diabetic Neuropathy? Diabetes 2014;63:2206–2208. Diabetes, 64(2), e2-e3.
Alam U, Asghar O, Petropoulos IN, Jeziorska M, Fadavi H, Ponirakis G, Marshall A, Tavakoli M, Boulton AJM, Efron N, et al (2015). Small Fiber Neuropathy in Patients with Latent Autoimmune Diabetes in Adults. Diabetes Care, 38(7), e102-e103.
Chen X, Graham J, Dabbah MA, Petropoulos IN, Ponirakis G, Asghar O, Alam U, Marshall A, Fadavi H, Ferdousi M, et al (2015). Small Nerve Fiber Quantification in the Diagnosis of Diabetic Sensorimotor Polyneuropathy: Comparing Corneal Confocal Microscopy with Intraepidermal Nerve Fiber Density.
Diabetes Care,
38(6), 1138-1144.
Abstract:
Small Nerve Fiber Quantification in the Diagnosis of Diabetic Sensorimotor Polyneuropathy: Comparing Corneal Confocal Microscopy with Intraepidermal Nerve Fiber Density
. OBJECTIVE
. Quantitative assessment of small fiber damage is key to the early diagnosis and assessment of progression or regression of diabetic sensorimotor polyneuropathy (DSPN). Intraepidermal nerve fiber density (IENFD) is the current gold standard, but corneal confocal microscopy (CCM), an in vivo ophthalmic imaging modality, has the potential to be a noninvasive and objective image biomarker for identifying small fiber damage. The purpose of this study was to determine the diagnostic performance of CCM and IENFD by using the current guidelines as the reference standard.
.
.
. RESEARCH DESIGN AND METHODS
. Eighty-nine subjects (26 control subjects and 63 patients with type 1 diabetes), with and without DSPN, underwent a detailed assessment of neuropathy, including CCM and skin biopsy.
.
.
. RESULTS
. Manual and automated corneal nerve fiber density (CNFD) (P &lt; 0.0001), branch density (CNBD) (P &lt; 0.0001) and length (CNFL) (P &lt; 0.0001), and IENFD (P &lt; 0.001) were significantly reduced in patients with diabetes with DSPN compared with control subjects. The area under the receiver operating characteristic curve for identifying DSPN was 0.82 for manual CNFD, 0.80 for automated CNFD, and 0.66 for IENFD, which did not differ significantly (P = 0.14).
.
.
. CONCLUSIONS
. This study shows comparable diagnostic efficiency between CCM and IENFD, providing further support for the clinical utility of CCM as a surrogate end point for DSPN.
.
Abstract.
Kass-Iliyya L, Javed S, Gosal D, Kobylecki C, Marshall A, Petropoulos IN, Ponirakis G, Tavakoli M, Ferdousi M, Chaudhuri KR, et al (2015). Small fiber neuropathy in Parkinson's disease: a clinical, pathological and corneal confocal microscopy study. Parkinsonism & Related Disorders, 21(12), 1454-1460.
Petropoulos IN, Ferdousi M, Marshall A, Alam U, Ponirakis G, Azmi S, Fadavi H, Efron N, Tavakoli M, Malik RA, et al (2015). The Inferior Whorl for Detecting Diabetic Peripheral Neuropathy Using Corneal Confocal Microscopy. Investigative Opthalmology & Visual Science, 56(4), 2498-2498.
Pacaud D, Romanchuk KG, Tavakoli M, Gougeon C, Virtanen H, Ferdousi M, Nettel-Aguirre A, Mah JK, Malik RA (2015). The Reliability and Reproducibility of Corneal Confocal Microscopy in Children. Investigative Opthalmology & Visual Science, 56(9), 5636-5636.
Javed S, Petropoulos IN, Tavakoli M, Malik RA (2014). Clinical and diagnostic features of small fiber damage in diabetic polyneuropathy.
Handb Clin Neurol,
126, 275-290.
Abstract:
Clinical and diagnostic features of small fiber damage in diabetic polyneuropathy.
Small fiber neuropathy represents a significant component of diabetic sensorimotor polyneuropathy (DSPN) which has to date been ignored in most recommendations for the diagnosis of DSPN. Small fibers predominate in the peripheral nerve, serve crucial and highly clinically relevant functions such as pain, and regulate microvascular blood flow, mediating the mechanisms underlying foot ulceration. An increasing number of diagnostic tests have been developed to quantify small fiber damage. Because small fiber damage precedes large fiber damage, diagnostic tests for DSPN show good sensitivity but moderate specificity, because the gold standard which is used to define DSPN is large fiber-weighted. Hence new diagnostic algorithms for DSPN should acknowledge this emerging data and incorporate small fiber evaluation as a key measure in the diagnosis of DSPN, especially early neuropathy.
Abstract.
Author URL.
Asghar O, Petropoulos IN, Alam U, Jones W, Jeziorska M, Marshall A, Ponirakis G, Fadavi H, Boulton AJM, Tavakoli M, et al (2014). Corneal Confocal Microscopy Detects Neuropathy in Subjects with Impaired Glucose Tolerance.
Diabetes Care,
37(9), 2643-2646.
Abstract:
Corneal Confocal Microscopy Detects Neuropathy in Subjects with Impaired Glucose Tolerance
. OBJECTIVE
. Impaired glucose tolerance (IGT) represents one of the earliest stages of glucose dysregulation and is associated with macrovascular disease, retinopathy, and microalbuminuria, but whether IGT causes neuropathy is unclear.
.
.
. RESEARCH DESIGN AND METHODS
. Thirty-seven subjects with IGT and 20 age-matched control subjects underwent a comprehensive evaluation of neuropathy by assessing symptoms, neurological deficits, nerve conduction studies, quantitative sensory testing, heart rate variability deep breathing (HRVdb), skin biopsy, and corneal confocal microscopy (CCM).
.
.
. RESULTS
. Subjects with IGT had a significantly increased neuropathy symptom profile (P &lt; 0.001), McGill pain index (P &lt; 0.001), neuropathy disability score (P = 0.001), vibration perception threshold (P = 0.002), warm threshold (P = 0.006), and cool threshold (P = 0.03), with a reduction in intraepidermal nerve fiber density (P = 0.03), corneal nerve fiber density (P &lt; 0.001), corneal nerve branch density (P = 0.002), and corneal nerve fiber length (P = 0.05). No significant difference was found in sensory and motor nerve amplitude and conduction velocity or HRVdb.
.
.
. CONCLUSIONS
. Subjects with IGT have evidence of neuropathy, particularly small-fiber damage, which can be detected using skin biopsy and CCM.
.
Abstract.
Azmi S, Ferdousi M, Petropoulos IN, Ponirakis G, Fadavi H, Tavakoli M, Alam U, Jones W, Marshall A, Jeziorska M, et al (2014). Corneal Confocal Microscopy Shows an Improvement in Small-Fiber Neuropathy in Subjects with Type 1 Diabetes on Continuous Subcutaneous Insulin Infusion Compared with Multiple Daily Injection. Diabetes Care, 38(1), e3-e4.
Pritchard N, Edwards K, Dehghani C, Fadavi H, Jeziorska M, Marshall A, Petropoulos IN, Ponirakis G, Russell AW, Sampson GP, et al (2014). Longitudinal assessment of neuropathy in type 1 diabetes using novel ophthalmic markers (LANDMark): Study design and baseline characteristics. Diabetes Research and Clinical Practice, 104(2), 248-256.
Petropoulos IN, Alam U, Fadavi H, Marshall A, Asghar O, Dabbah MA, Chen X, Graham J, Ponirakis G, Boulton AJM, et al (2014). Rapid Automated Diagnosis of Diabetic Peripheral Neuropathy with in Vivo Corneal Confocal Microscopy. Investigative Opthalmology & Visual Science, 55(4), 2071-2071.
Ponirakis G, Petropoulos IN, Fadavi H, Alam U, Asghar O, Marshall A, Tavakoli M, Malik RA (2014). The diagnostic accuracy of Neuropad<sup>®</sup>for assessing large and small fibre diabetic neuropathy. Diabetic Medicine, 31(12), 1673-1680.
Petropoulos IN, Alam U, Fadavi H, Asghar O, Green P, Ponirakis G, Marshall A, Boulton AJM, Tavakoli M, Malik RA, et al (2013). Corneal Nerve Loss Detected with Corneal Confocal Microscopy is Symmetrical and Related to the Severity of Diabetic Polyneuropathy.
Diabetes Care,
36(11), 3646-3651.
Abstract:
Corneal Nerve Loss Detected with Corneal Confocal Microscopy is Symmetrical and Related to the Severity of Diabetic Polyneuropathy
. OBJECTIVE
. To establish if corneal nerve loss, detected using in vivo corneal confocal microscopy (IVCCM), is symmetrical between right and left eyes and relates to the severity of diabetic neuropathy.
.
.
. RESEARCH DESIGN AND METHODS
. Patients (n = 111) with type 1 and type 2 diabetes and 47 age-matched healthy control subjects underwent detailed assessment and stratification into no (n = 50), mild (n = 26), moderate (n = 17), and severe (n = 18) neuropathy. IVCCM was performed in both eyes and corneal nerve fiber density (CNFD), branch density (CNBD), and fiber length (CNFL) and the tortuosity coefficient were quantified.
.
.
. RESULTS
. All corneal nerve parameters differed significantly between diabetic patients and control subjects and progressively worsened with increasing severity of neuropathy. The reduction in CNFD, CNBD, and CNFL was symmetrical in all groups except in patients with severe neuropathy.
.
.
. CONCLUSIONS
. IVCCM noninvasively detects corneal nerve loss, which relates to the severity of neuropathy, and is symmetrical, except in those with severe diabetic neuropathy.
.
Abstract.
Tavakoli M, Petropoulos IN, Malik RA (2013). Corneal confocal microscopy to assess diabetic neuropathy: an eye on the foot.
J Diabetes Sci Technol,
7(5), 1179-1189.
Abstract:
Corneal confocal microscopy to assess diabetic neuropathy: an eye on the foot.
Accurate detection and quantification of human diabetic peripheral neuropathy are important to define at-risk patients, anticipate deterioration, and assess new therapies. Easily performed clinical techniques such as neuro-logical examination, assessment of vibration perception or insensitivity to the 10 g monofilament only assess advanced neuropathy, i.e. the at-risk foot. Techniques that assess early neuropathy include neurophysiology (which assesses only large fibers) and quantitative sensory testing (which assesses small fibers), but they can be highly subjective while more objective techniques, such as skin biopsy for intra-epidermal nerve fiber density quantification, are invasive and not widely available. The emerging ophthalmic technique of corneal confocal microscopy allows quantification of corneal nerve morphology and enables clinicians to diagnose peripheral neuropathy in diabetes patients, quantify its severity, and potentially assess therapeutic benefit. The present review provides a detailed critique of the rationale, a practical approach to capture images, and a basis for analyzing and interpreting the images. We also critically evaluate the diagnostic ability of this new noninvasive ophthalmic test to diagnose diabetic and other peripheral neuropathies.
Abstract.
Author URL.
Tavakoli M (2013). Corneal confocal microscopy: Beyond corneal defects! Translational studies in diabetes and neurology. Contact Lens and Anterior Eye, 36, e1-e1.
Alimohammadi S, Hobbenaghi R, Javanbakht J, Kheradmand D, Mortezaee R, Tavakoli M, Khadivar F, Akbari H (2013). Protective and antidiabetic effects of extract from Nigella sativa on blood glucose concentrations against streptozotocin (STZ)-induced diabetic in rats: an experimental study with histopathological evaluation.
Diagn Pathol,
8Abstract:
Protective and antidiabetic effects of extract from Nigella sativa on blood glucose concentrations against streptozotocin (STZ)-induced diabetic in rats: an experimental study with histopathological evaluation.
BACKGROUND: Diabetes in humans induces chronic complications such as cardiovascular damage, cataracts and retinopathy, nephropathy and polyneuropathy. The most common animal model of human diabetes is streptozotocin (STZ)-induced diabetes in the rat. The present study investigated the effects of Nigella sativa hydroalcholic extract on glucose concentrations in streptozotocin (STZ) diabetic rats. METHODS: in this study Twenty-five Wister-Albino rats (aged 8-9 weeks and weighing 200-250 g) were tested. Rats were divided into five experimental groups (control, untreated STZ-diabetic (60 mg/kg B.W. IP), treated STZ-diabetic with hydroalcholic extract of Nigella Sativa (NS) (5 mg/kg B.W, IP), treated STZ-diabetic with hydroalcholic extract of NS (10 mg/kg B.W. IP) and treated STZ-diabetic with hydroalcholic extract of NS (20 mg/kg B.W. IP and 32 days were evaluated to assess its effect on fasting blood glucose (FBG), and in different groups fasting blood glucose (FBG) and body weight (BW) were measured in the particular days (1, 16 and 32). At the end of the study, the animals were fasted overnight, anaesthetized with an intraperitoneal injection of sodium pentobarbital (60 mg/kg), and sacrificed for obtaining tissues samples (liver, pancreases). The number of islets and cells were counted and the islet diameters were determined by calibrated micrometer. The glycogen content in the liver was examined by Periodic Acid-Schiff (PAS) staining. RESULTS: Treatment with NS (5 mg/kg b.w.) markedly increased BW gain and the FBG level was significantly (p
Abstract.
Author URL.
Petropoulos IN, Manzoor T, Morgan P, Fadavi H, Asghar O, Alam U, Ponirakis G, Dabbah MA, Chen X, Graham J, et al (2013). Repeatability of in Vivo Corneal Confocal Microscopy to Quantify Corneal Nerve Morphology. Cornea, 32(5), e83-e89.
Safiarian R, Amini P, Moez EK, Mohammadzadeh F, Tavakoli M, Zayeri F (2013). Risk group classification for bleeding after coronary artery bypass graft surgery: a comparison of the logistic regression with decision tree models.
TURK GOGUS KALP DAMAR CERRAHISI DERGISI-TURKISH JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY,
21(3), 574-580.
Author URL.
Sellers EAC, Clark I, Tavakoli M, Dean HJ, McGavock J, Malik RA (2013). The acceptability and feasibility of corneal confocal microscopy to detect early diabetic neuropathy in children: a pilot study. Diabetic Medicine, 30(5), 630-631.
Tavakoli M, Mitu-Pretorian M, Petropoulos IN, Fadavi H, Asghar O, Alam U, Ponirakis G, Jeziorska M, Marshall A, Efron N, et al (2012). Corneal Confocal Microscopy Detects Early Nerve Regeneration in Diabetic Neuropathy After Simultaneous Pancreas and Kidney Transplantation.
Diabetes,
62(1), 254-260.
Abstract:
Corneal Confocal Microscopy Detects Early Nerve Regeneration in Diabetic Neuropathy After Simultaneous Pancreas and Kidney Transplantation
Diabetic neuropathy is associated with increased morbidity and mortality. To date, limited data in subjects with impaired glucose tolerance and diabetes demonstrate nerve fiber repair after intervention. This may reflect a lack of efficacy of the interventions but may also reflect difficulty of the tests currently deployed to adequately assess nerve fiber repair, particularly in short-term studies. Corneal confocal microscopy (CCM) represents a novel noninvasive means to quantify nerve fiber damage and repair. Fifteen type 1 diabetic patients undergoing simultaneous pancreas–kidney transplantation (SPK) underwent detailed assessment of neurologic deficits, quantitative sensory testing (QST), electrophysiology, skin biopsy, corneal sensitivity, and CCM at baseline and at 6 and 12 months after successful SPK. At baseline, diabetic patients had a significant neuropathy compared with control subjects. After successful SPK there was no significant change in neurologic impairment, neurophysiology, QST, corneal sensitivity, and intraepidermal nerve fiber density (IENFD). However, CCM demonstrated significant improvements in corneal nerve fiber density, branch density, and length at 12 months. Normalization of glycemia after SPK shows no significant improvement in neuropathy assessed by the neurologic deficits, QST, electrophysiology, and IENFD. However, CCM shows a significant improvement in nerve morphology, providing a novel noninvasive means to establish early nerve repair that is missed by currently advocated assessment techniques.
Abstract.
Tavakoli M, Marshall A, Banka S, Petropoulos IN, Fadavi H, Kingston H, Malik RA (2012). Corneal confocal microscopy detects small-fiber neuropathy in Charcot-Marie-Tooth disease type 1A patients. Muscle & Nerve, 46(5), 698-704.
Razmju H, Akhlaghi MR, Tavakoli M (2012). Evaluation of intravitreal injection of bevacizumab (Avastin) in treatment of diabetic macular edema in patients referring to Feiz Eye Hospital, Isfahan, Iran.
JOURNAL OF RESEARCH IN MEDICAL SCIENCES,
17, S79-S82.
Author URL.
Dabbah MA, Graham J, Petropoulos IN, Tavakoli M, Malik RA (2011). Automatic analysis of diabetic peripheral neuropathy using multi-scale quantitative morphology of nerve fibres in corneal confocal microscopy imaging. Medical Image Analysis, 15(5), 738-747.
Tavakoli M, Malik RA (2011). Corneal Confocal Microscopy: a Novel Non-invasive Technique to Quantify Small Fibre Pathology in Peripheral Neuropathies. Journal of Visualized Experiments(47).
Tavakoli M, Malik RA (2011). Corneal Confocal Microscopy: a Novel Non-invasive Technique to Quantify Small Fibre Pathology in Peripheral Neuropathies. Journal of Visualized Experiments(47).
Tavakoli M, Kallinikos P, Iqbal A, Herbert A, Fadavi H, Efron N, Boulton AJM, a Malik R (2011). Corneal confocal microscopy detects improvement in corneal nerve morphology with an improvement in risk factors for diabetic neuropathy. Diabetic Medicine, 28(10), 1261-1267.
Tavakoli M, Boulton AJM, Efron N, Malik RA (2011). Increased Langerhan cell density and corneal nerve damage in diabetic patients: Role of immune mechanisms in human diabetic neuropathy. Contact Lens and Anterior Eye, 34(1), 7-11.
Zhivov A, Stachs O (2011). Re: “Increased Langerhan cell density and corneal nerve damage in diabetic patients: Role of immune mechanisms in human diabetic neuropathy” by Tavakoli et al. Contact Lens and Anterior Eye, 34(2), 98-98.
Efron N, Tavakoli M, Boulton AJM, Malik R (2011). Reply to letter from Dr Zhivov and Dr Stachs. Contact Lens and Anterior Eye, 34(2), 99-99.
Tavakoli M, Quattrini C, Abbott C, Kallinikos P, Marshall A, Finnigan J, Morgan P, Efron N, Boulton AJM, Malik RA, et al (2010). Corneal Confocal Microscopy.
Diabetes Care,
33(8), 1792-1797.
Abstract:
Corneal Confocal Microscopy
. OBJECTIVE
. The accurate quantification of human diabetic neuropathy is important to define at-risk patients, anticipate deterioration, and assess new therapies.
.
.
. RESEARCH DESIGN AND METHODS
. A total of 101 diabetic patients and 17 age-matched control subjects underwent neurological evaluation, neurophysiology tests, quantitative sensory testing, and evaluation of corneal sensation and corneal nerve morphology using corneal confocal microscopy (CCM).
.
.
. RESULTS
. Corneal sensation decreased significantly (P = 0.0001) with increasing neuropathic severity and correlated with the neuropathy disability score (NDS) (r = 0.441, P &lt; 0.0001). Corneal nerve fiber density (NFD) (P &lt; 0.0001), nerve fiber length (NFL), (P &lt; 0.0001), and nerve branch density (NBD) (P &lt; 0.0001) decreased significantly with increasing neuropathic severity and correlated with NDS (NFD r = −0.475, P &lt; 0.0001; NBD r = −0.511, P &lt; 0.0001; and NFL r = −0.581, P &lt; 0.0001). NBD and NFL demonstrated a significant and progressive reduction with worsening heat pain thresholds (P = 0.01). Receiver operating characteristic curve analysis for the diagnosis of neuropathy (NDS &gt;3) defined an NFD of &lt;27.8/mm2 with a sensitivity of 0.82 (95% CI 0.68–0.92) and specificity of 0.52 (0.40–0.64) and for detecting patients at risk of foot ulceration (NDS &gt;6) defined a NFD cutoff of &lt;20.8/mm2 with a sensitivity of 0.71 (0.42–0.92) and specificity of 0.64 (0.54–0.74).
.
.
. CONCLUSIONS
. CCM is a noninvasive clinical technique that may be used to detect early nerve damage and stratify diabetic patients with increasing neuropathic severity.
.
Abstract.
Tavakoli M, Marshall A, Pitceathly R, Fadavi H, Gow D, Roberts ME, Efron N, Boulton AJM, Malik RA (2010). Corneal confocal microscopy: a novel means to detect nerve fibre damage in idiopathic small fibre neuropathy. Experimental Neurology, 223(1), 245-250.
Tavakoli M, Marshall A, Pitceathly R, Fadavi H, Gow D, Roberts ME, Efron N, Boulton AJM, Malik RA (2010). Corneal confocal microscopy: a novel means to detect nerve fibre damage in idiopathic small fibre neuropathy.
EXPERIMENTAL NEUROLOGY,
223(1), 245-250.
Author URL.
Petropoulos I, Fadavi H, Asghar O, Alam U, Ponirakis G, Tavakoli M, Malik R (2010). Diabetic neuropathy: Review of diagnosis and management.
Diabetes and Primary Care,
12(3), 165-174.
Abstract:
Diabetic neuropathy: Review of diagnosis and management
Diabetic neuropathy is common, under- or misdiagnosed, and causes not only substantial morbidity but also increased mortality. Apart from improving glycaemic control, there is no licensed treatment for diabetic neuropathy, although a number of pathogenetic pathways remain under active study. Focal and multifocal neuropathies are not common but can be extremely debilitating with few proven therapies. Autonomic dysfunction is more common, but significant deficits, although severe, are relatively rare, with limited therapeutic options. Painful diabetic neuropathy is a cause of considerable morbidity and many pharmacological as well as non-pharmacological interventions have been used. The recent NICE (2010) guidance provides an evidence-based rationale for the management of neuropathic pain in primary care. © John Wiley and Sons 2008.
Abstract.
Dabbah MA, Graham J, Petropoulos I, Tavakoli M, Malik RA (2010). Dual-model automatic detection of nerve-fibres in corneal confocal microscopy images.
Med Image Comput Comput Assist Interv,
13(Pt 1), 300-307.
Abstract:
Dual-model automatic detection of nerve-fibres in corneal confocal microscopy images.
Corneal Confocal Microscopy (CCM) imaging is a non-invasive surrogate of detecting, quantifying and monitoring diabetic peripheral neuropathy. This paper presents an automated method for detecting nerve-fibres from CCM images using a dual-model detection algorithm and compares the performance to well-established texture and feature detection methods. The algorithm comprises two separate models, one for the background and another for the foreground (nerve-fibres), which work interactively. Our evaluation shows significant improvement (p approximately 0) in both error rate and signal-to-noise ratio of this model over the competitor methods. The automatic method is also evaluated in comparison with manual ground truth analysis in assessing diabetic neuropathy on the basis of nerve-fibre length, and shows a strong correlation (r = 0.92). Both analyses significantly separate diabetic patients from control subjects (p approximately 0).
Abstract.
Author URL.
Tavakoli M, Asghar O, Alam U, Petropoulos IN, Fadavi H, Malik RA (2010). Review: Novel insights on diagnosis, cause and treatment of diabetic neuropathy: focus on painful diabetic neuropathy.
Therapeutic Advances in Endocrinology and Metabolism,
1(2), 69-88.
Abstract:
Review: Novel insights on diagnosis, cause and treatment of diabetic neuropathy: focus on painful diabetic neuropathy
Diabetic neuropathy is common, under or misdiagnosed, and causes substantial morbidity with increased mortality. Defining and developing sensitive diagnostic tests for diabetic neuropathy is not only key to implementing earlier interventions but also to ensure that the most appropriate endpoints are employed in clinical intervention trials. This is critical as many potentially effective therapies may never progress to the clinic, not due to a lack of therapeutic effect, but because the endpoints were not sufficiently sensitive or robust to identify benefit. Apart from improving glycaemic control, there is no licensed treatment for diabetic neuropathy, however, a number of pathogenetic pathways remain under active study. Painful diabetic neuropathy is a cause of considerable morbidity and whilst many pharmacological and nonpharmacological interventions are currently used, only two are approved by the US Food and Drug Administration. We address the important issue of the ‘placebo effect’ and also consider potential new pharmacological therapies as well as nonpharmacological interventions in the treatment of painful diabetic neuropathy.
Abstract.
Patel DV, Tavakoli M, Craig JP, Efron N, McGhee CNJ (2009). Corneal Sensitivity and Slit Scanning in Vivo Confocal Microscopy of the Subbasal Nerve Plexus of the Normal Central and Peripheral Human Cornea. Cornea, 28(7), 735-740.
Tavakoli M, Marshall A, Thompson L, Kenny M, Waldek S, Efron N, Malik RA (2009). Corneal confocal microscopy: a novel noninvasive means to diagnose neuropathy in patients with fabry disease. Muscle & Nerve, 40(6), 976-984.
Tavakoli M, Fadavi H, Malik RA (2008). Advances in the Diagnosis and Treatment of Painful Diabetic Neuropathy.
European Endocrinology,
4, 48-48.
Abstract:
Advances in the Diagnosis and Treatment of Painful Diabetic Neuropathy
Abstract.
Malik R (2008). Clinical applications of corneal confocal microscopy. Clinical Ophthalmology, 435-435.
Mehra S, Tavakoli M, Tavakoli A, Parrott N, Malik R, Augustine T (2008). IMPROVEMENT IN DIABETIC NEUROPATHY AFTER SUCCESSFUL PANCREAS TRANSPLANTATION DETECTED BY CORNEAL CONFOCAL MICROSCOPY- TWO YEAR DATA. Transplantation, 86(2S).
Tavakoli M, Malik RA (2008). Management of painful diabetic neuropathy.
Expert Opin Pharmacother,
9(17), 2969-2978.
Abstract:
Management of painful diabetic neuropathy.
The commonest cause of peripheral neuropathy is diabetes and pain occurs in approximately 30% of diabetic patients with neuropathy. It is extremely distressing for the patient and poses significant difficulties in management, as no treatment to date provides total relief and the side effects of therapy limit dose titration. Understanding the pathogenesis of diabetic neuropathy may lead to the development of new treatments for preventing nerve damage. Furthermore, a better understanding of the mechanisms that modulate pain may lead to more effective relief of painful symptoms. This review provides an update on the assessment and treatment of painful diabetic neuropathy.
Abstract.
Author URL.
Tavakoli M, Mojaddidi M, Fadavi H, Malik RA (2008). Pathophysiology and treatment of painful diabetic neuropathy. Current Pain and Headache Reports, 12(3), 192-197.
Quattrini C, Jeziorska M, Tavakoli M, Begum P, Boulton AJM, Malik RA (2008). The Neuropad test: a visual indicator test for human diabetic neuropathy. Diabetologia, 51(6), 1046-1050.
Mehra S, Tavakoli M, Kallinikos PA, Efron N, Boulton AJM, Augustine T, Malik RA (2007). Corneal Confocal Microscopy Detects Early Nerve Regeneration After Pancreas Transplantation in Patients with Type 1 Diabetes.
Diabetes Care,
30(10), 2608-2612.
Abstract:
Corneal Confocal Microscopy Detects Early Nerve Regeneration After Pancreas Transplantation in Patients with Type 1 Diabetes
OBJECTIVE—Corneal confocal microscopy (CCM) is a rapid, noninvasive, clinical examination technique that quantifies small nerve fiber pathology. We have used it to assess the neurological benefits of pancreas transplantation in type 1 diabetic patients.
. RESEARCH DESIGN AND METHODS—In 20 patients with type 1 diabetes undergoing simultaneous pancreas and kidney transplantation (SPK) and 15 control subjects, corneal sensitivity was evaluated using noncontact corneal esthesiometry, and small nerve fiber morphology was assessed using CCM.
. RESULTS—Corneal sensitivity (1.54 ± 0.28 vs. 0.77 ± 0.02, P &lt; 0.0001), nerve fiber density (NFD) (13.8 ± 2.1 vs. 42 ± 3.2, P &lt; 0.0001), nerve branch density (NBD) (4.04 ± 1.5 vs. 26.7 ± 2.5, P &lt; 0.0001), and nerve fiber length (NFL) (2.23 ± 0.2 vs. 9.69 ± 0.7, P &lt; 0.0001) were significantly reduced, and nerve fiber tortuosity (NFT) (15.7 ± 1.02 vs. 19.56 ± 1.34, P = 0.04) was increased in diabetic patients before pancreas transplantation. Six months after SPK, 15 patients underwent a second assessment and showed a significant improvement in NFD (18.04 ± 10.48 vs. 9.25 ± 1.87, P = 0.001) and NFL (3.60 ± 0.33 vs. 1.84 ± 0.33, P = 0.002) with no change in NBD (1.38 ± 0.74 vs. 1.38 ± 1.00, P = 1.0), NFT (15.58 ± 1.20 vs. 16.30 ± 1.19, P = 0.67), or corneal sensitivity (1.23 ± 0.39 vs. 1.54 ± 00.42, P = 0.59).
. CONCLUSIONS—Despite marked nerve fiber damage in type 1 diabetic patients undergoing pancreas transplantation, small fiber repair can be detected within 6 months of pancreas transplantation using CCM. CCM is a novel noninvasive clinical technique to assess the benefits of therapeutic intervention in human diabetic neuropathy.
Abstract.
Tavakoli M, Kallinikos PA, Efron N, Boulton AJM, Malik RA (2007). Corneal Sensitivity is Reduced and Relates to the Severity of Neuropathy in Patients with Diabetes. Diabetes Care, 30(7), 1895-1897.
Dash SK (2007). Corneal Sensitivity is Reduced and Relates to the Severity of Neuropathy in Patients with Diabetes. Diabetes Care, 30(12), e142-e142.
Tavakoli M, Kallinikos PA, Efron N, Boulton AJM, Malik RA (2007). Corneal sensitivity is reduced and relates to the severity of neuropathy in patients with diabetes: Response to Dash [16]. Diabetes Care, 30(12).
Greenstein A, Tavakoli M, Mojaddidi M, Al-Sunni A, Matfin G, Malik RA (2007). Microvascular complications: Evaluation and monitoring relevance to clinical practice, clinical trials, and drug development.
British Journal of Diabetes and Vascular Disease,
7(4), 166-171.
Abstract:
Microvascular complications: Evaluation and monitoring relevance to clinical practice, clinical trials, and drug development
The long-term microvascular complications of diabetes pose a major health burden. Although, much of the focus has been on the macrovascular complications, it is clear that the microvascular complications have a significant impact on both morbidity and mortality amongst diabetic patients. Indeed retinopathy, nephropathy, and neuropathy compete as the leading causes of premature blindness, end-stage renal disease, and non-traumatic lower-limb amputation, respectively. Furthermore, complications develop and progress in unison and indeed share many common risk factors. Effective evaluation and monitoring of these complications in clinical practice is clearly important, however, it is also relevant to clinical intervention studies, and drug development programs addressing microvascular complications. Novel diagnostic and therapeutic strategies are continually evolving in this area and will be discussed in more detail in this review.
Abstract.
Quattrini C, Tavakoli M, Jeziorska M, Kallinikos P, Tesfaye S, Finnigan J, Marshall A, Boulton AJM, Efron N, Malik RA, et al (2007). Surrogate Markers of Small Fiber Damage in Human Diabetic Neuropathy.
Diabetes,
56(8), 2148-2154.
Abstract:
Surrogate Markers of Small Fiber Damage in Human Diabetic Neuropathy
Surrogate markers of diabetic neuropathy are being actively sought to facilitate the diagnosis, measure the progression, and assess the benefits of therapeutic intervention in patients with diabetic neuropathy. We have quantified small nerve fiber pathological changes using the technique of intraepidermal nerve fiber (IENF) assessment and the novel in vivo technique of corneal confocal microscopy (CCM). Fifty-four diabetic patients stratified for neuropathy, using neurological evaluation, neurophysiology, and quantitative sensory testing, and 15 control subjects were studied. They underwent a punch skin biopsy to quantify IENFs and CCM to quantify corneal nerve fibers. IENF density (IENFD), branch density, and branch length showed a progressive reduction with increasing severity of neuropathy, which was significant in patients with mild, moderate, and severe neuropathy. CCM also showed a progressive reduction in corneal nerve fiber density (CNFD) and branch density, but the latter was significantly reduced even in diabetic patients without neuropathy. Both IENFD and CNFD correlated significantly with cold detection and heat as pain thresholds. Intraepidermal and corneal nerve fiber lengths were reduced in patients with painful compared with painless diabetic neuropathy. Both IENF and CCM assessment accurately quantify small nerve fiber damage in diabetic patients. However, CCM quantifies small fiber damage rapidly and noninvasively and detects earlier stages of nerve damage compared with IENF pathology. This may make it an ideal technique to accurately diagnose and assess progression of human diabetic neuropathy.
Abstract.
Mehra S, Tavakoli M, Palmer A, Tavakoli A, Pararajasingam R, Parrott NR, Malik R, Augustine T (2006). EARLY NEURAL REGENERATION AFTER PANCREAS TRANSPLANTATION DETECTED BY CORNEAL CONFOCAL MICROSCOPY: a PILOT STUDY. Transplantation, 82(1).
Mojaddidi M, Quattrini C, Tavakoli M, Malik RA (2005). Recent developments in the assessment of efficacy in clinical trials of diabetic neuropathy. Current Diabetes Reports, 5(6), 417-422.
Tavakoli M (2001). Yekta AA, Tavakoli M, Study of the prevalence of types and amounts of refractive errors in different ages among patients examined at the department of optometry, Mashad University of Medical Sciences, Iranian J. Basic Medical Sciences 2001; 4: 106-115. Iranian J. Basic Medical Sciences, 4, 106-115.
Gellman DD, Pirani CL, Soothill JF, Muehrcke RC, Kark RM (1959). Diabetic nephropathy: a clinical and pathologic study based on renal biopsies. Medicine (United States), 38(4), 321-367.
Chapters
Carmichael J, Fadavi H, Ishibashi F, Shore AC, Tavakoli M (2022). Chapter 4 Advances in screening, early diagnosis, and accurate staging of diabetic neuropathy. In (Ed) Diabetic Neuropathy, 47-78.
Javed S, Petropoulos IN, Tavakoli. M, Malik RA, Tavakoli M (2014). Chapter 20: Clinical and diagnostic features of small fiber damage in diabetic polyneuropathy. In (Ed) Handbook of Clinical Neurology
Diabetes and the Nervous System, Elsevier B.V, 275-290.
Tavakoli M (2014). Chapter 3: Neuropatia de fibra fina: novas abordagens diagnósticas. In Hermelinda C. Pedrosa, Lucio Vilar, Andrew J. M. Boulton (Eds.)
Neuropatias e Pé Diabético.
Abstract:
Chapter 3: Neuropatia de fibra fina: novas abordagens diagnósticas
Abstract.
Tavakoli M, Fadavi H, Malik RA (2014). Optimal Measures of Small Fiber Neuropathy in Diabetic Polyneuropathy. In (Ed)
Studies in Diabetes, Springer Science & Business Media, 93-105.
Abstract:
Optimal Measures of Small Fiber Neuropathy in Diabetic Polyneuropathy.
Abstract.
Tavakoli M, Mojaddidi M, Fadavi H, Malik RA (2009). Chapter 2 Pathogenesis of human diabetic neuropathy. In (Ed) Diabetic Neuropathy, Oxford University Press.
Tavakoli M (2009). Pathogenesis of Human Diabetic Neuropathy. In (Ed)
Diabetic Neuropathy, Oxford University Press, USA.
Abstract:
Pathogenesis of Human Diabetic Neuropathy
Abstract.
Conferences
Tavakoli M, Ishibashi F (2019). Impact of Extensive HbA1c Control on Major Microvascular Complications in Type 2 Diabetes Mellitus with Short Duration of Disease.
Author URL.
Tavakoli M, Ishibashi F (2019). Impact of normalised HbA1c on diabetic neuropathy and other microvascular complications in Type 2 diabetes.
Author URL.
Perkins BA, Lovblom LE, Bril V, Ferdousi M, Orszag A, Edwards K, Pritchard N, Russell AW, Dehghani C, Pacaud D, et al (2019). Prediction of Future Neuropathy Onset Using Corneal Confocal Microscopy: a Longitudinal Multinational Consortium Study.
Author URL.
Lewis EJH, Lovblom LE, Ferdousi M, Jeziorska M, Pacaud D, Pritchard N, Shtein RM, Efron N, Tavakoli M, Bril V, et al (2019). Rapid Corneal Nerve Fibre Loss Predicts Neuropathy Progression in Diabetes: a Longitudinal Multinational Consortium Study.
Author URL.
Tavakoli M, Ishibashi F (2018). Impact of normoglycaemia in reducing microvascular complications in patients with type 2 diabetes.
Author URL.
Tavakoli M, Ishibashi F (2018). The Impact of Normoglycemia in Reducing Microvascular Complications in Patients with Type 2 Diabetes-A Follow-Up Study.
Author URL.
Lewis EJH, Tavakoli M, Lovblom LE, Halpern EM, Jeziorska M, Pacaud D, Pritchard N, Shtein RM, Efron N, Bril V, et al (2018). The Reference Distribution of Annual Change in Corneal Nerve Fibre Length in Diabetes Mellitus.
Author URL.
Osigian CJ, Grace S, Cavuoto KM, Feuer WJ, Tavakoli M, Capo H, Lam BL (2017). Comparison of Non-Sedated Cone Flicker ERG Screening Test and Sedated Conventional ERG in Children.
Author URL.
Perkins BA, Lovblom LE, Bril V, Edwards K, Pritchard N, Russell A, Pacaud D, Romanchuk K, Mah J, Boulton AJM, et al (2017). Concurrent Diagnostic Validity of in Vivo Corneal Confocal Microscopy for the Diagnosis of Diabetic Polyneuropathy (DPN): a Pooled Multinational Analysis.
Author URL.
Alam U, Petropoulos IN, Fadavi H, Asghar O, Marshall A, Jeziorska M, Azmi S, Pritchard N, Ponirakis G, Edwards K, et al (2017). Corneal Confocal Microscopy Detects a Small-Fibre Neuropathy in Patients with LADA.
Author URL.
Tavakoli M, Soiland-Reyes C, Spencer R, Howard S, Boaden R (2017). Corneal Confocal Microscopy for Early Detection of Diabetic Neuropathy in Newly Diagnosed Patients with Type 2 Diabetes Mellitus.
Author URL.
Azmi S, Alam U, Ferdousi M, Petropoulos IN, Ponirakis G, Fadavi H, Asghar O, Marshall A, Jones W, Tavakoli M, et al (2017). Corneal Confocal Microscopy: a Viable Surrogate Endpoint for Neuropathy following Simultaneous Pancreas Kidney Transplant.
Author URL.
Alam U, Petropoulos IN, Fadavi H, Asghar O, Ponirakis G, Jeziorska M, Marshall A, Tavakoli M, Boulton AJM, Efron N, et al (2017). Corneal confocal microscopy detects improvements in small nerve fibres in subjects with latent autoimmune diabetes in adults with enhanced glycaemic control.
Author URL.
Tavakoli M (2017). Evaluation of clinical diagnostic markers for early detection of diabetic neuropathy.
Author URL.
Tavakoli M, Howard S, Soiland-Reyes C, Spencer R, Cotterill S, Perry C, Boaden R (2017). IMPLEMENTATION OF CORNEAL CONFOCAL MICROSCOPY FOR SCREENING DIABETIC NEUROPATHY IN PRIMARY CARE: a FEASIBILITY AND ACCEPTABILITY STUDY.
Author URL.
Tavakoli M, Manchester E-CG (2017). Screening and Early Detection of Diabetic Neuropathy in Newly Diagnosed Type 2 Diabetes Mellitus.
Author URL.
Azmi S, Jeziorska M, Ferdousi M, Petropoulos I, Ponirakis G, Marshall A, Alam U, Fadavi H, Tavakoli M, Asghar O, et al (2017). Simultaneous pancreas kidney transplantation in type 1 diabetes is associated with an early improvement in small fibres.
Author URL.
Sankar A, Fadavi H, Ferdousi M, Marshall A, Azmi S, Tavakoli M, Boulton AJM, Malik RA (2016). Corneal Confocal Microscopy Distinguishes between Painful and Painless Diabetic Peripheral Neuropathy.
Author URL.
Sankar A, Fadavi H, Ferdousi M, Marshall A, Azmi S, Tavakoli M, Boulton AJM, Malik RA (2016). Corneal confocal microscopy differentiates patients with painful from painless diabetic neuropathy.
Author URL.
Tavakoli M, Ferdousi M, Petropoulos L, Morris J, Pritchard N, Romanchuk K, Pacaud D, Perkins BA, Brill V, Ziegler D, et al (2015). A Multinational Normative Dataset for Corneal Nerve Morphology Assessed Using Corneal Confocal Microscopy.
Author URL.
Tavakoli M, Ferdousi M, Petropoulos I, Morris J, Pritchard N, Zhivov A, Ziegler D, Pacaud D, Romanchuk K, Perkins B, et al (2015). A multi-national normative dataset for corneal nerve morphological parameters with using corneal confocal microscopy for early diagnosing diabetic neuropathy.
Author URL.
Javed S, Ponirakis G, Ferdousi M, Azmi S, Petropoulos I, Tavakoli M, Jeziorska M, Gosal D, Malik RA (2015). Corneal confocal microscopy detects small-fibre damage, particularly in patients with sensory and autonomic ISFN.
Author URL.
Tavakoli M, Ferdousi M, Petropoulos I, Fadavi H, Boulton AJM, Malik R (2015). NEURO - DEGENERATION OF CORNEA AND RETINA IN PATIENTS WITH TYPE 1 DIABETES WITHOUT CLINICAL EVIDENCE OF DIABETIC RETINOPATHY AND NEUROPATHY.
Author URL.
Azmi S, Ferdousi M, Ponirakis G, Petropoulos I, Schofield J, Fadavi H, Tavakoli M, Soran H, Malik RA (2015). Obesity related neuropathy and the effects of bariatric surgery.
Author URL.
Azmi S, Ferdousi M, Ponirakis G, Alam U, Petropoulos I, Marshall A, Tavakoli M, Ammori B, Soran H, Malik R, et al (2015). Obesity related neuropathy and the effects of bariatric surgery.
Author URL.
Azmi S, Ferdousi M, Ponirakis G, Petropoulos IN, Alam U, Tavakoli M, Fadavi H, Schofield J, Siahmansur T, Marshall A, et al (2015). Obesity-related Neuropathy and the Effects of Bariatric Surgery.
Author URL.
Tavakoli M, Malik R (2015). The Acceptability and Feasibility of Corneal Confocal Microscopy to Detect Diabetic Neuropathy in Children: a Pilot Study.
Author URL.
Ponirakis G, Odriozola M, Petropoulos IN, Azmi S, Ferdousi M, Fadavi H, Alam U, Asghar O, Mashall A, Tavakoli M, et al (2015). The Diagnostic Validity of Nervecheck: from Functional and Structural Damage of Small and Large Nerve Fibres to Neuropathic Pain.
Author URL.
Azmi S, Ponirakis G, Ferdousi M, Petropoulos IN, Alam U, Marshall A, Kheyami A, Fadavi H, Tavakoli M, Boulton AJM, et al (2014). Corneal Confocal Microscopy (CCM) Detects an Improvement in Small Fibre Neuropathy in Subjects with Type 1 Diabetes Mellitus (T1DM) on Continuous Subcutaneous Insulin Infusion (CSII).
Author URL.
Alam U, Azmi S, Ferdousi M, Petropoulos IN, Ponirakis G, Fadavi H, Tavakoli M, Marshall A, Boulton AJM, Malik RA, et al (2014). Corneal Confocal Microscopy (CCM) Identifies Early Small Fibre Neuropathy and Predicts the Development of Microalbuminuria in Type 1 Diabetes (T1DM).
Author URL.
Tavakoli M, Begum P, Malik RA, Mclaughlin J (2014). Corneal Confocal Microscopy for the Diagnosis of Autonomic Neuropathy in Diabetic Gastroenteropathy.
Author URL.
Pacaud D, Romanchuk K, Tavakoli M, Gougeon C, Ferdousi M, Mah JK, Nettel-Aguirre A, Malik RA (2014). Corneal Confocal Microscopy in Children with Type 1 Diabetes: Interobserver Agreement and Repeatability of Nerve Fiber Length Measurements.
Author URL.
Azmi S, Petropoulos I, Ferdousi MF, Ponirakis G, Alam U, Fadavi HF, Tavakoli M, Kheyami A, Jeziorska M, Malik RA, et al (2014). Corneal confocal microscopy detects early nerve damage in subjects with impaired glucose tolerance and predicts progression to diabetes.
Author URL.
Ponirakis G, Petropoulos I, Fadavi HF, Uazman AU, Asghar OA, Jeziorska M, Ferdousi MF, Marshall AM, Tavakoli M, Malik RAM, et al (2014). Corneal confocal microscopy: a prognostic test for the development of diabetic neuropathy.
Author URL.
Alam U, Petropoulos IN, Asghar O, Azmi S, Fadavi H, Marshall A, Tavakoli M, Boulton AJM, Efron N, Malik RA, et al (2014). Diabetic Neuropathy in Patients with Latent Autoimmune Diabetes in Adults (LADA).
Author URL.
Tavakoli M, Ferdousi M, Petropoulos IN, Fadavi H, Marshall A, Boulton AJM, Malik RA (2014). Ophthalmic biomarkers of diabetic neuropathy: does neural dysfunction precede vascular changes?.
Author URL.
Tavakoli M, Ferdousi M, Petropoulos I, Malik R (2014). Retinal and Corneal neural dysfunction precedes retinopathy and correlates with peripheral neuropathy in patients with Type 1 diabetes.
Author URL.
Alahmar A, Fadavi H, Alam U, Asghar O, Petropoulos IN, Ferdousi M, Ponirakis G, Meskiri A, Jones W, Azmi S, et al (2014). Skin AGE/RAGE Expression is Related to the Severity of Diabetic Neuropathy.
Author URL.
Alam U, Petropoulos IN, Fadavi H, Asghar O, Marshall A, Ponirakis G, Al-Ahmar A, Kheyami A, Ferdousi M, Azmi S, et al (2013). Corneal Confocal Microscopy is as Proficient as Electrophysiology and Skin Biopsy in Detecting Neuropathy in Subjects with Type 1 Diabetes Mellitus.
Author URL.
Tavakoli M, Malik R (2013). Corneal Confocal Microscopy detects neuropathy before retinopathy and nephropathy in children with Type 1 Diabetes: a Preliminary Study.
Author URL.
Petropoulos IN, Asghar O, Alam U, Fadavi H, Ponirakis G, Marshall A, Tavakoli M, Boulton AJM, Malik RA (2013). Corneal confocal microscopy detects and tracks progression of neuropathy in subjects with impaired glucose tolerance.
Author URL.
Tavakoli M, Mitu-Pretorian M, Petropoulos IN, Fadavi H, Asghar O, Alam U, Ponirakis G, Jeziorska M, Marshall A, Boulton AJM, et al (2013). Corneal confocal microscopy detects early nerve regeneration in diabetic neuropathy following simultaneous pancreas and kidney transplantation.
Author URL.
Tavakoli M, Malik RA (2013). Corneal confocal microscopy detects neuropathy before retinopathy and nephropathy in children with type 1 diabetes: a preliminary study.
Author URL.
Ponirakis G, Petropoulos IP, Fadavi H, Alam UA, Asghar OA, Tavakoli M, Malik RAM (2013). Diagnostic performance of Neuropad response.
Author URL.
Azmi S, Alam U, Fadavi H, Asghar O, Petropoulos IN, Ponirakis G, Marshall A, Ferdousi M, Kheyami A, Alahmar A, et al (2013). Early Non-Progressive Small Fibre Neuropathy in Type 2 Diabetes.
Author URL.
Efron N, Pritchard N, Edwards K, Sampson G, Russell A, Petropoulos I, Alam U, Fadavi H, Tavakoli M, Malik R, et al (2013). Longitudinal Assessment of Neuropathy in Diabetes using novel ophthalmic MARKers (LANDMark): Baseline findings.
Author URL.
Khambalia H, Tavakoli M, Moinuddin Z, van Dellen D, Malik R, Augustine T (2013). Simultaneous Pancreas and Kidney Transplantation leads to Early Nerve Regeneration, as Evaluated by Corneal Confocal Microscopy.
Author URL.
Alam U, Petropoulos I, Fadavi H, Asghar O, Marshall A, Ponirakis G, Tavakoli M, Boulton AJ, Malik R (2012). Small Fibre Dysfunction and Vitamin D Deficiency Underlie Painful Diabetic Neuropathy.
Author URL.
Tavakoli M, Toosi MHB, Pourreza R, Banaee T, Pourreza HR, IEEE (2011). Automated Optic Nerve Head Detection in Fluorescein Angiography Fundus Images.
Author URL.
Asghar O, Petropoulos IN, Alam U, Ponirakis G, Fadavi H, Marshall A, Tavakoli M, Boulton AJM, Malik RA (2011). Corneal Confocal Microscopy Detects Neuropathy in Impaired Glucose Tolerance.
Author URL.
Tavakoli M, Petropoulos I, Fadavi H, Alam U, Asghar O, Ponirakis G, Boulton AJM, Malik RA (2011). Corneal nerve fibre damage defined using corneal confocal microscopy in relation to tear film proteomics.
Author URL.
Fadavi H, Tavakoli M, Petropolous IN, Caturvedi N, Jeziorska M, Boulton AJM, Malik RA, Abbott CA (2011). Potential explanation for lower incidence of foot ulceration in Asian compared to European patients with type 2 diabetes.
Author URL.
Alam U, Fadavi H, Petropoulos I, Ponirakis G, Asghar O, Marshall A, Tavakoli M, Boulton AJM, Malik RA (2011). Protection from Neuropathy: Lessons from Patients with Long Duration Type 1 Diabetes.
Author URL.
Quattrini C, Tavakoli M, Kallinikos P, Marshall A, Efron N, Boulton AJM, Malik RA (2010). Comparing skin biopsy with corneal confocal microscopy: diagnostic yield of nerve fiber density.
Author URL.
Petropoulos IN, Asghar O, Alam U, Fadavi H, Dabbah MA, Marshall A, Tavakoli M, Boulton AJM, Malik RA (2010). Corneal Confocal Microscopy Detects Neuropathy in Subjects with Impaired Glucose Tolerance.
Author URL.
Dabbah MA, Graham J, Petropoulos I, Tavakoli M, Malik RA (2010). Dual-model automatic detection of nerve-fibres in corneal confocal microscopy images.
Abstract:
Dual-model automatic detection of nerve-fibres in corneal confocal microscopy images
Abstract.
Tavakoli M, Quattrini C, Begum P, Fadavi H, Boulton AJM, Malik RA (2010). Neuropad and corneal confocal microscopy: new indicators for human diabetic neuropathy.
Author URL.
Fadavi H, Tavakoli M, Petropoulos I, Chaturvedi N, Boulton AJM, Malik R, Abbott CA (2010). Predisposing Risk Factors Underlying the Reduced Risk of Foot Ulceration in South Asian Compared to European Patient with Diabetes.
Author URL.
Begum P, Tavakoli M, Malik RA, McLaughlin J (2009). AN "INSIGHT" INTO DIABETIC GASTROENTEROPATHY USING CORNEAL CONFOCAL MICROSCOPY.
Author URL.
Tavakoli M, Begum P, McLaughlin J, Malik RA (2009). Corneal confocal microscopy: a novel surrogate marker for diabetic autonomic neuropathy.
Author URL.
Fadavi H, Tavakoli M, Finnigan J, Doyle S, Chaturvedi N, Boulton AJM, Malik RA, Abbott CA (2009). Reduced Small Nerve Fibre Damage May Underlie a Lower Incidence of Foot Ulceration in Asian Compared to European Patients with Diabetes.
Author URL.
Tavakoli M, Mehra S, Boulton AJ, Augustine T-T, Malik RA (2008). Corneal confocal microscopy detects early nerve regeneration in type 1 diabetic patients undergoing combined pancreas/kidney transplantation.
Author URL.
Pitceathly RDS, Tavakoli M, Marshall A, Roberts ME, Gow D, Efron N, Malik RA (2008). Corneal confocal microscopy to diagnose idiopathic small fibre neuropathy.
Author URL.
Tavakoli M, Marshall A, Roberts ME, Malik RA (2008). Corneal diabetic neuropathy: a new hallmark of peripheral diabetic neuropathy.
Author URL.
Tavakoli M, Abbott C, Quattrini C, Middlemas A, Karamoysoyli E, Tomlinson DR, Boulton AJM, Malik RA (2007). Corneal confocal microscopy and plasma p75NTR: new surrogate markers of human diabetic neuropathy.
Author URL.
Mehra S, Tavakoli M, Kallinikos P, Efron N, Boulton AJM, Augustine T, Malik RA (2007). Corneal confocal microscopy detects early nerve regeneration after pancreas transplantation in diabetic patients despite severe neuropathy.
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Mehra S, Tavakoli M, Tavakoli A, Malik R, Parajasingam R, Parrott NR, Augustine TA (2007). Corneal confocal microscopy detects early neural regeneration in type 1 diabetics after pancreas transplantation.
Author URL.
Tavakoli M, Middlemas A, Kararrloysoli E, Abbott C, Quattrini C, Malik RA, Boulton AJM, Tomlinson DR (2007). Is p75NTR a new surrogate marker of diabetic neuropathy?.
Author URL.
Tavakoli M, Mehra S, Augustine T, Malik RA (2006). Corneal confocal microscopy detects early nerve regeneration after pancreas transplantation.
Author URL.
Tavakoli M, Quattrini C, Abbott C, Kallinikos P, Tomlinson D, Efron N, Boulton AJM, Malik RA (2006). Corneal confocal microscopy is a non-invasive surrogate of nerve fibre damage and repair in diabetic patients.
Author URL.
Quattrini C, Kallinikos P, Tavakoli M, Jeziorska M, Sheard A, Finnigan J, Boulton A, Efron N, Malik R (2005). Corneal confocal microscopy is superior to skin biopsy as a surrogate marker of human diabetic neuropathy.
Author URL.
Publications by year
In Press
Tavakoli M (In Press). Ophthalmic Biomarkers of Alzheimer's disease: a review. Frontiers in Aging Neuroscience
2023
Al-Hinnawi A-RM, BaniMustafa A, Al-Latayfeh M, Tavakoli M (2023). Reconstruction and Visualization of 5μm Sectional Coronal Views for Macula Vasculature in OptoVue OCTA. IEEE Access, 11, 28280-28293.
2022
Carmichael J, Fadavi H, Ishibashi F, Shore AC, Tavakoli M (2022). Chapter 4 Advances in screening, early diagnosis, and accurate staging of diabetic neuropathy. In (Ed) Diabetic Neuropathy, 47-78.
Pacaud D, Romanchuk KG, Virtanen H, Ferdousi M, Nettel-Aguirre A, Mah JK, Tavakoli M, Zochodne DW, Malik RA (2022). Corneal nerve and nerve conduction abnormalities in children with type 1 diabetes.
Pediatr Diabetes,
23(8), 1665-1673.
Abstract:
Corneal nerve and nerve conduction abnormalities in children with type 1 diabetes.
OBJECTIVE: in vivo corneal confocal microscopy (CCM) is a novel, rapid, and non-invasive technique that identifies early small fiber damage and can predict the progression and development of clinical neuropathy in adults with type 1 diabetes. However, its usefulness in children is not well established. This study compared corneal confocal microscopy with neuropathic symptoms, signs, and objective measures of neuropathy for the diagnosis of diabetic neuropathy in children with type 1 diabetes. RESEARCH DESIGN AND METHODS: a total of 83 children with type 1 diabetes and 83 healthy participants of similar age underwent assessment of neuropathy symptoms, signs, nerve conduction studies, quantitative sensory and autonomic function testing, and in vivo CCM. RESULTS: Only of 3/83 (4%) children with type 1 diabetes had subclinical neuropathy. However, corneal nerve fiber density (p = 0.001), branch density (p = 0.006), fiber length (p = 0.002), tibial motor nerve amplitude and conduction velocity, and sural sensory nerve amplitude and conduction velocity (all p 0.05) between children with type 1 diabetes and healthy controls. Multivariate regression analysis identified a possible association between body mass index and decreased corneal nerves. CONCLUSIONS: Decreased corneal nerves and abnormal nerve conduction were found in children with type 1 diabetes. CCM may allow rapid objective detection of subclinical diabetic neuropathy in children and adolescents with type 1 diabetes.
Abstract.
Author URL.
Tavakoli M (2022).
Diabetic Neuropathy.Abstract:
Diabetic Neuropathy
Abstract.
Carmichael J, Fadavi H, Ishibashi F, Howard S, Boulton AJM, Shore AC, Tavakoli M (2022). Implementation of corneal confocal microscopy for screening and early detection of diabetic neuropathy in primary care alongside retinopathy screening: Results from a feasibility study.
Frontiers in Endocrinology,
13Abstract:
Implementation of corneal confocal microscopy for screening and early detection of diabetic neuropathy in primary care alongside retinopathy screening: Results from a feasibility study
Objective: Screening for diabetic peripheral neuropathy (DPN) is essential for early detection and timely intervention. Quantitative assessment of small nerve fiber damage is key to the early diagnosis and assessment of its progression. Corneal confocal microscopy (CCM) is a non-invasive, in-vivo diagnostic technique that provides an accurate surrogate biomarker for small-fiber neuropathy. In this novel study for the first time, we introduced CCM to primary care as a screening tool for DPN alongside retinopathy screening to assess the level of neuropathy in this novel cohort. Research design and methods: 450 consecutive subjects with type 1 or type 2 diabetes attending for annual eye screening in primary care optometry settings underwent assessment with CCM to establish the prevalence of sub-clinical diabetic peripheral neuropathy. Subjects underwent assessment for neurological and ocular symptoms of diabetes and a history of diabetic foot disease, neuropathy and diabetic retinopathy (DR). Results: CCM examination was completed successfully in 427 (94.9%) subjects, 22% of whom had neuropathy according to Diabetic Neuropathy Symptom (DNS) score. The prevalence of sub-clinical neuropathy as defined by abnormal corneal nerve fiber length (CNFL) was 12.9%. In the subjects with a short duration of type 2 diabetes, 9.2% had abnormal CNFL. CCM showed significant abnormalities in corneal nerve parameters in this cohort of subjects with reduction of corneal nerve fiber density (CNFD, p
Abstract.
Ishibashi F, Kosaka A, Tavakoli M (2022). Sodium Glucose Cotransporter-2 Inhibitor Protects Against Diabetic Neuropathy and Nephropathy in Modestly Controlled Type 2 Diabetes: Follow-Up Study. Frontiers in Endocrinology, 13
2021
Carmichael J, Fadavi H, Ishibashi F, Shore AC, Tavakoli M (2021). Advances in Screening, Early Diagnosis and Accurate Staging of Diabetic Neuropathy.
FRONTIERS IN ENDOCRINOLOGY,
12 Author URL.
Tavakoli M, Petropoulos IN, Malik RA (2021). Assessing corneal nerve structure and function in diabetic neuropathy. Clinical and Experimental Optometry, 95(3), 338-347.
Perkins BA, Lovblom LE, Lewis EJH, Bril V, Ferdousi M, Orszag A, Edwards K, Pritchard N, Russell A, Dehghani C, et al (2021). Corneal Confocal Microscopy Predicts the Development of Diabetic Neuropathy: a Longitudinal Diagnostic Multinational Consortium Study.
Diabetes Care,
44(9), 2107-2114.
Abstract:
Corneal Confocal Microscopy Predicts the Development of Diabetic Neuropathy: a Longitudinal Diagnostic Multinational Consortium Study.
OBJECTIVE: Corneal nerve fiber length (CNFL) has been shown in research studies to identify diabetic peripheral neuropathy (DPN). In this longitudinal diagnostic study, we assessed the ability of CNFL to predict the development of DPN. RESEARCH DESIGN AND METHODS: from a multinational cohort of 998 participants with type 1 and type 2 diabetes, we studied the subset of 261 participants who were free of DPN at baseline and completed at least 4 years of follow-up for incident DPN. The predictive validity of CNFL for the development of DPN was determined using time-dependent receiver operating characteristic (ROC) curves. RESULTS: a total of 203 participants had type 1 and 58 had type 2 diabetes. Mean follow-up time was 5.8 years (interquartile range 4.2-7.0). New-onset DPN occurred in 60 participants (23%; 4.29 events per 100 person-years). Participants who developed DPN were older and had a higher prevalence of type 2 diabetes, higher BMI, and longer duration of diabetes. The baseline electrophysiology and corneal confocal microscopy parameters were in the normal range but were all significantly lower in participants who developed DPN. The time-dependent area under the ROC curve for CNFL ranged between 0.61 and 0.69 for years 1-5 and was 0.80 at year 6. The optimal diagnostic threshold for a baseline CNFL of 14.1 mm/mm2 was associated with 67% sensitivity, 71% specificity, and a hazard ratio of 2.95 (95% CI 1.70-5.11; P < 0.001) for new-onset DPN. CONCLUSIONS: CNFL showed good predictive validity for identifying patients at higher risk of developing DPN ∼6 years in the future.
Abstract.
Author URL.
Carmichael J (2021). Corneal confocal microscopy for diagnosis of diabetic peripheral neuropathy: an analysis of patients with diabetes screened as part of the South Manchester Diabetic Retinopathy Screening Service.
Abstract:
Corneal confocal microscopy for diagnosis of diabetic peripheral neuropathy: an analysis of patients with diabetes screened as part of the South Manchester Diabetic Retinopathy Screening Service
Background and Aims: Quantitative assessment of small nerve fibre damage is key to the early diagnosis of diabetic peripheral neuropathy (DPN) and assessment of its progression. Corneal confocal microscopy (CCM) is a non-invasive, in-vivo diagnostic technique that provides an accurate surrogate biomarker for small fibre neuropathy. Its diagnostic efficacy has been previously validated in several studies. This thesis uses CCM images obtained, for the first time, in a large cohort of patients whose CCM examinations were undertaken during retinopathy screening in primary care. The following were the primary aims of the study:
1. To determine the prevalence of diabetic peripheral neuropathy, as defined by CCM parameters in a cohort of people with diabetes
2.To assess whether abnormalities in corneal nerve fibre morphology are present during the first two years following diabetes diagnosis.
3. To assess whether abnormalities in corneal nerve morphology are present prior to any retinopathy, defined as grade 1 or more.
4. To assess whether abnormalities in corneal nerve morphology are present prior to clinical evidence of diabetic neuropathy, as defined by diabetic neuropathic symptom (DNS) scoring of 1 or more
The hypotheses for these main aims were that firstly, the prevalence of diabetic peripheral neuropathy, defined using CCM parameters would be lower in this population in comparison to previous CCM studies using patients under the hospital eye service to determine prevalence of DPN. There will be evidence of abnormalities in corneal nerve fibre morphology in some, but not all, patients with diabetic disease duration of less than or equal to 2 years, patients with retinopathy and maculopathy grade 0 and patients with a DNS score of 0.
Methods: in this retrospective, primary care, cross-sectional study, 427 patients with diabetes (18 T1DM, 407 T2DM, 2 unknown) and 40 healthy controls underwent quantification of corneal nerve parameters using both automated and semi-automated analysis software. Clinical levels of neuropathy were assessed via diabetic neuropathy symptom score (DNS). Diabetic Retinopathy (DR) was graded using the Early Treatment Diabetic Retinopathy Study (ETDRS) grading scale.
Results: Patients with diabetes demonstrated significant differences in all nerve parameters in comparison to healthy control subjects (p
Abstract.
Celiker H, Erekul G, Turhan SA, Kokar S, Yavuz DG, Gunduz OH, Tavakoli M, Toker E (2021). Early detection of neuropathy in patients with type 2 diabetes with or without microalbuminuria in the absence of peripheral neuropathy and retinopathy.
J Fr Ophtalmol,
44(4), 485-493.
Abstract:
Early detection of neuropathy in patients with type 2 diabetes with or without microalbuminuria in the absence of peripheral neuropathy and retinopathy.
PURPOSE: Our goal is early detection of neuropathy in patients with type 2 diabetes with or without microalbuminuria in the absence of diabetic retinopathy and peripheral neuropathy by using in vivo corneal confocal microscopy (IVCCM). METHODS: a total of 60 type-2 diabetic patients, assigned to either a diabetes mellitus (DM) with microalbuminuria group (DM/MA+, n=30) or a DM without microalbuminuria group (DM/MA-, n=30), and 30 age-matched control subjects were enrolled in this study. All cases underwent evaluation of blood glucose level, HbA1c, lipid fractions, body mass index (BMI), and corneal sensitivity (CS). Corneal nerve fiber length (NFL), nerve fiber density (NFD), nerve branch density (NBD), and tortuosity coefficient (TC) were quantified by IVCCM. None of the patients had peripheral neuropathy or retinopathy. RESULTS: Compared with the healthy subjects, NFL and NFD were reduced in both diabetic groups (P
Abstract.
Author URL.
Ando A, Miyamoto M, Saito N, Kotani K, Kamiya H, Ishibashi S, Tavakoli M (2021). Small Fibre Neuropathy is Associated with Impaired Vascular Endothelial Function in Patients with Type 2 Diabetes.
Frontiers in Endocrinology,
12Abstract:
Small Fibre Neuropathy is Associated with Impaired Vascular Endothelial Function in Patients with Type 2 Diabetes
Diabetic polyneuropathy (DPN) and endothelial dysfunction are prevalent complications of diabetes mellitus. Currently, there are two non-invasive markers for endothelial dysfunction: flow-mediated dilation and reactive hyperaemia peripheral arterial tonometry (RH-PAT). However, the relationship between diabetic small fibre neuropathy and macroangiopathy remains obscure thus far. Corneal confocal microscopy (CCM) has emerged as a new diagnostic modality to assess DPN, especially of small fibre. To clarify the relationship between diabetic small fibre neuropathy and vascular dysfunction, we aimed to determine the functions of peripheral nerves and blood vessels through clinical tests such as nerve conduction study, coefficient of variation in the R-R interval, CCM, and RH-PAT in 82 patients with type 2 diabetes. Forty healthy control subjects were also included to study corneal nerve parameters. Correlational and multiple linear regression analyses were performed to determine the associations between neuropathy indices and markers for vascular functions. The results revealed that patients with type 2 diabetes had significantly lower values for most variables of CCM than healthy control subjects. RH-PAT solely remained as an explanatory variable significant in multiple regression analysis for several CCM parameters and vice versa. Other vascular markers had no significant multiple regression with any CCM parameters. In conclusion, endothelial dysfunction as revealed by impaired RH-PAT was significantly associated with CCM parameters in patients with type 2 diabetes. This association may indicate that small fibre neuropathy results from impaired endothelial dysfunction in type 2 diabetes. CCM parameters may be considered surrogate markers of autonomic nerve damage, which is related to diabetic endothelial dysfunction. This study is the first to report the relationship between corneal nerve parameter as small fibre neuropathy in patients with type 2 diabetes and RH-PAT as a marker of endothelial dysfunction.
Abstract.
Ishibashi F, Kosaka A, Tavakoli M (2021). The Impact of Glycemic Control on Retinal Photoreceptor Layers and Retinal Pigment Epithelium in Patients with Type 2 Diabetes Without Diabetic Retinopathy: a Follow-Up Study.
Frontiers in Endocrinology,
12Abstract:
The Impact of Glycemic Control on Retinal Photoreceptor Layers and Retinal Pigment Epithelium in Patients with Type 2 Diabetes Without Diabetic Retinopathy: a Follow-Up Study
AimsTo establish the sequential changes by glycemic control in the mean thickness, volume and reflectance of the macular photoreceptor layers (MPRLs) and retinal pigment epithelium in patients with type 2 diabetes without diabetic retinopathy.MethodsThirty-one poorly controlled (HbA1c &gt; 8.0%) patients with type 2 diabetes without diabetic retinopathy undergoing glycemic control and 39 control subjects with normal HbA1c levels (&lt; 5.9%) underwent periodical full medical, neurological and ophthalmological examinations over 2 years. Glycemic variability was evaluated by standard deviation and coefficient of variation of monthly measured HbA1c levels and casual plasma glucose. 3D swept source-optical coherence tomography (OCT) and OCT-Explorer-generated enface thickness, volume and reflectance images for 9 subfields defined by Early Treatment Diabetic Retinopathy Study of 4 MPRLs {outer nuclear layer, ellipsoid zone, photoreceptor outer segment (PROS) and interdigitation zone} and retinal pigment epithelium were acquired every 3 months.ResultsGlycemic control sequentially restored the thickness and volume at 6, 4 and 5 subfields of outer nuclear layer, ellipsoid zone and PROS, respectively. The thickness and volume of outer nuclear layer were restored related to the decrease in HbA1c and casual plasma glucose levels, but not related to glycemic variability and neurological tests. The reflectance of MPRLs and retinal pigment epithelium in patients was marginally weaker than controls, and further decreased at 6 or 15 months during glycemic control. The reduction at 6 months coincided with high HbA1c levels.ConclusionGlycemic control sequentially restored the some MPRL thickness, especially of outer nuclear layer. In contrast, high glucose during glycemic control decreased reflectance and may lead to the development of diabetic retinopathy induced by glycemic control. The repeated OCT examinations can clarify the benefit and hazard of glycemic control to the diabetic retinopathy.
Abstract.
2020
Lewis EJH, Lovblom LE, Ferdousi M, Halpern EM, Jeziorska M, Pacaud D, Pritchard N, Dehghani C, Edwards K, Srinivasan S, et al (2020). Rapid Corneal Nerve Fiber Loss: a Marker of Diabetic Neuropathy Onset and Progression.
Diabetes Care,
43(8), 1829-1835.
Abstract:
Rapid Corneal Nerve Fiber Loss: a Marker of Diabetic Neuropathy Onset and Progression
. OBJECTIVE
. Corneal nerve fiber length (CNFL) represents a biomarker for diabetic distal symmetric polyneuropathy (DSP). We aimed to determine the reference distribution of annual CNFL change, the prevalence of abnormal change in diabetes, and its associated clinical variables.
.
.
. RESEARCH DESIGN AND METHODS
. We examined 590 participants with diabetes (399 with type 1 diabetes [T1D] and 191 with type 2 diabetes [T2D]) and 204 control patients without diabetes with at least 1 year of follow-up and classified them according to rapid corneal nerve fiber loss (RCNFL) if CNFL change was below the 5th percentile of the control patients without diabetes.
.
.
. RESULTS
. Control patients without diabetes were 37.9 ± 19.8 years old, had median follow-up of three visits over 3.0 years, and mean annual change in CNFL was −0.1% (90% CI −5.9% to 5.0%). RCNFL was defined by values exceeding the 5th percentile of 6% loss. Participants with T1D were 39.9 ± 18.7 years old, had median follow-up of three visits over 4.4 years, and mean annual change in CNFL was −0.8% (90% CI −14.0% to 9.9%). Participants with T2D were 60.4 ± 8.2 years old, had median follow-up of three visits over 5.3 years, and mean annual change in CNFL was −0.2% (90% CI −14.1% to 14.3%). RCNFL prevalence was 17% overall and was similar by diabetes type (64 T1D [16.0%], 37 T2D [19.4%], P = 0.31). RNCFL was more common in those with baseline DSP (47% vs. 30% in those without baseline DSP, P = 0.001), which was associated with lower peroneal conduction velocity but not with baseline HbA1c or its change over follow-up.
.
.
. CONCLUSIONS
. An abnormally rapid loss of CNFL of 6% per year or more occurs in 17% of diabetes patients. RCNFL may identify patients at highest risk for the development and progression of DSP.
.
Abstract.
Ishibashi F, Tavakoli M (2020). Thinning of Macular Neuroretinal Layers Contributes to Sleep Disorder in Patients with Type 2 Diabetes Without Clinical Evidences of Neuropathy and Retinopathy. Frontiers in Endocrinology, 11
2019
Tavakoli M, Ishibashi F (2019). Impact of Extensive HbA1c Control on Major Microvascular Complications in Type 2 Diabetes Mellitus with Short Duration of Disease.
Author URL.
Tavakoli M, Ishibashi F (2019). Impact of normalised HbA1c on diabetic neuropathy and other microvascular complications in Type 2 diabetes.
Author URL.
Ishibashi F, Taniguchi M, Kosaka A, Uetake H, Tavakoli M (2019). Improvement in Neuropathy Outcomes with Normalizing HbA1c in Patients with Type 2 Diabetes.
Diabetes Care,
42(1), 110-118.
Abstract:
Improvement in Neuropathy Outcomes with Normalizing HbA1c in Patients with Type 2 Diabetes.
OBJECTIVE: to investigate the impact of normalizing HbA1c by extensive HbA1c control (EHC) on neuropathy outcome measures (NOMs), nephropathy, and retinopathy in type 2 diabetes. RESEARCH DESIGN AND METHODS: Detailed clinical and neurological examinations were performed in two cohorts of 38 patients with uncontrolled type 2 diabetes (HbA1c 9.6% [81.4 mmol/mol]) at baseline and after glycemic control (GC) with or without EHC by diet restriction and hypoglycemic agents over 4 years along with 48 control subjects with normal glucose tolerance (NGT) and 34 subjects with impaired glucose tolerance (IGT) only at baseline. EHC patients, control subjects, and subjects with IGT underwent oral glucose tolerance tests. Glycemic variability (GV) was evaluated by SD and coefficient of variation of monthly measured HbA1c levels and casual plasma glucose. RESULTS: in the EHC cohort, HbA1c levels over 4.3 years and the last 2 years improved to 6.1% (43.2 mmol/mol) and 5.8% (39.9 mmol/mol) with 7.3 kg body wt reduction, and 50% and 28.9% of patients returned to IGT and NGT, respectively, at end point. Baseline neurophysiological and corneal nerve fiber (CNF) measures were impaired in patients. Normalized HbA1c with EHC improved neurophysiological and CNF measures to be similar for those for IGT, while GC without EHC (mean HbA1c level 7.0% [53.5 mmol/mol]) improved only vibration perception. The mean normalized HbA1c levels by EHC determined NOM improvements. The high GV and baseline HbA1c levels compromised NOMs. Albumin excretion rate significantly decreased, while retinopathy severity and frequency insignificantly worsened on EHC. CONCLUSIONS: Normalizing HbA1c in type 2 diabetes of short duration improves microvascular complications including neuropathy and nephropathy more effectively than standard GC but not retinopathy.
Abstract.
Author URL.
Perkins BA, Lovblom LE, Bril V, Ferdousi M, Orszag A, Edwards K, Pritchard N, Russell AW, Dehghani C, Pacaud D, et al (2019). Prediction of Future Neuropathy Onset Using Corneal Confocal Microscopy: a Longitudinal Multinational Consortium Study.
Author URL.
Lewis EJH, Lovblom LE, Ferdousi M, Jeziorska M, Pacaud D, Pritchard N, Shtein RM, Efron N, Tavakoli M, Bril V, et al (2019). Rapid Corneal Nerve Fibre Loss Predicts Neuropathy Progression in Diabetes: a Longitudinal Multinational Consortium Study.
Author URL.
2018
Lewis EJ, Tavakoli M, Lovblom LE, Halpern EM, Jeziorska M, Pacaud D, Pritchard N, Shtein RM, Efron N, Bril V, et al (2018). 26 the Reference Distribution of Annual Change in Corneal Nerve Fibre Length in Diabetes. Canadian Journal of Diabetes, 42(5).
Perkins BA, Lovblom LE, Bril V, Scarr D, Ostrovski I, Orszag A, Edwards K, Pritchard N, Russell A, Dehghani C, et al (2018). Corneal confocal microscopy for identification of diabetic sensorimotor polyneuropathy: a pooled multinational consortium study.
Diabetologia,
61(8), 1856-1861.
Abstract:
Corneal confocal microscopy for identification of diabetic sensorimotor polyneuropathy: a pooled multinational consortium study
Aims/hypothesis: Small cohort studies raise the hypothesis that corneal nerve abnormalities (including corneal nerve fibre length [CNFL]) are valid non-invasive imaging endpoints for diabetic sensorimotor polyneuropathy (DSP). We aimed to establish concurrent validity and diagnostic thresholds in a large cohort of participants with and without DSP. Methods: Nine hundred and ninety-eight participants from five centres (516 with type 1 diabetes and 482 with type 2 diabetes) underwent CNFL quantification and clinical and electrophysiological examination. AUC and diagnostic thresholds were derived and validated in randomly selected samples using receiver operating characteristic analysis. Sensitivity analyses included latent class models to address the issue of imperfect reference standard. Results: Type 1 and type 2 diabetes subcohorts had mean age of 42 ± 19 and 62 ± 10 years, diabetes duration 21 ± 15 and 12 ± 9 years and DSP prevalence of 31% and 53%, respectively. Derivation AUC for CNFL was 0.77 in type 1 diabetes (p < 0.001) and 0.68 in type 2 diabetes (p < 0.001) and was approximately reproduced in validation sets. The optimal threshold for automated CNFL was 12.5 mm/mm2 in type 1 diabetes and 12.3 mm/mm2 in type 2 diabetes. In the total cohort, a lower threshold value below 8.6 mm/mm2 to rule in DSP and an upper value of 15.3 mm/mm2 to rule out DSP were associated with 88% specificity and 88% sensitivity. Conclusions/interpretation: We established the diagnostic validity and common diagnostic thresholds for CNFL in type 1 and type 2 diabetes. Further research must determine to what extent CNFL can be deployed in clinical practice and in clinical trials assessing the efficacy of disease-modifying therapies for DSP.
Abstract.
Fadavi H, Tavakoli M, Foden P, Ferdousi M, Petropoulos IN, Jeziorska M, Chaturvedi N, Boulton AJM, Malik RA, Abbott CA, et al (2018). Explanations for less small fibre neuropathy in South Asian versus European subjects with type 2 diabetes in the UK.
Diabetes Metab Res Rev,
34(7).
Abstract:
Explanations for less small fibre neuropathy in South Asian versus European subjects with type 2 diabetes in the UK.
BACKGROUND: Low foot ulcer risk in South Asian, compared with European, people with type 2 diabetes in the UK has been attributed to their lower levels of neuropathy. We have undertaken a detailed study of corneal nerve morphology and neuropathy risk factors, to establish the basis of preserved small nerve fibre function in South Asians versus Europeans. METHODS: in a cross-sectional, population-based study, age- and sex-matched South Asians (n = 77) and Europeans (n = 78) with type 2 diabetes underwent neuropathy assessment using corneal confocal microscopy, symptoms, signs, quantitative sensory testing, electrophysiology and autonomic function testing. Multivariable linear regression analyses determined factors accounting for ethnic differences in small fibre damage. RESULTS: Corneal nerve fibre length (22.0 ± 7.9 vs. 19.3 ± 6.3 mm/mm2 ; P = 0.037), corneal nerve branch density (geometric mean (range): 60.0 (4.7-246.2) vs. 46.0 (3.1-129.2) no./mm2 ; P = 0.021) and heart rate variability (geometric mean (range): 7.9 (1.4-27.7) vs. 6.5 (1.5-22.0); P = 0.044), were significantly higher in South Asians vs. Europeans. All other neuropathy measures did not differ, except for better sural nerve amplitude in South Asians (geometric mean (range): 10.0 (1.3-43.0) vs. 7.2 (1.0-30.0); P = 0.006). Variables with the greatest impact on attenuating the P value for age- and HbA1C -adjusted ethnic difference in corneal nerve fibre length (P = 0.032) were pack-years smoked (P = 0.13), BMI (P = 0.062) and triglyceride levels (P = 0.062). CONCLUSIONS: South Asians have better preserved small nerve fibre integrity than equivalent Europeans; furthermore, classic, modifiable risk factors for coronary heart disease are the main contributors to these ethnic differences. We suggest that improved autonomic neurogenic control of cutaneous blood flow in Asians may contribute to their protection against foot ulcers.
Abstract.
Author URL.
Tavakoli M, Ishibashi F (2018). Impact of normoglycaemia in reducing microvascular complications in patients with type 2 diabetes.
Author URL.
Ishibashi F, Tavakoli M (2018). Impact of normoglycemia in reducing microvascular complications in patients with type 2 diabetes: a follow-up study.
Frontiers in Endocrinology,
9(MAR).
Abstract:
Impact of normoglycemia in reducing microvascular complications in patients with type 2 diabetes: a follow-up study
Aims: Hyperglycemia is associated with an increased risk of microvascular complications in patients with type 2 diabetes. The aim of the present study was to investigate whether the reduction of the levels of HbA1c by tight glycemic control (GC) decreases the rate of microvascular complications and improves the neurological measures in patients with type 2 diabetes. Methods: Detailed clinical and neurological examinations including corneal confocal microscopy (CCM) were performed in 141 Japanese patients with type 2 diabetes and 60 age-matched control subjects at baseline and follow-up with GC for 4 years. Patients were stratified according to the mean HbA1c level during follow-up into good (HbA1c < 53.0 mmol/mol, mean; 47.5 mmol/mol), fair (53.0 mmol/mol ≤ HbA1c < 58.5 mmol/mol, mean; 55.6 mmol/mol), and poor (HbA1c ≥ 58.5 mmol/mol, mean; 68.9 mmol/mol) GC groups with similar HbA1c levels at baseline (84.5-88.2 mmol/mol). Results: at baseline, CCM revealed significant nerve fiber damage in all patients compared to that in controls. The interval changes in most corneal nerve fiber (CNF) parameters and neurophysiological functions were significantly related with the mean HbA1c levels during follow-up. Interestingly, the baseline HbA1c level did not impact on neurological functions at follow-up. Interval changes in neuropathy outcomes were associated with mean clinical factors during follow-up and hypoglycemic strategies. Good GC improved all nerve functions, including CNF branch density and bead, but not the length and main fiber density. Fair GC deteriorated some nerve functions. Poor GC compromised all neuropathy outcomes. Irrespective of GC levels, retinopathy increased after follow-up period, while nephropathy decreased. Conclusion: This study showed that tight GC was beneficial just for nephropathy among microvascular complications. Despite strict GC, the retinopathy progressed in patients with type 2 diabetes. Glucose control did not improve neurophysiological and corneal nerve measurements unless near-normoglycemia was reached.
Abstract.
Tavakoli M, Ishibashi F (2018). The Impact of Normoglycemia in Reducing Microvascular Complications in Patients with Type 2 Diabetes-A Follow-Up Study.
Author URL.
Lewis EJH, Tavakoli M, Lovblom LE, Halpern EM, Jeziorska M, Pacaud D, Pritchard N, Shtein RM, Efron N, Bril V, et al (2018). The Reference Distribution of Annual Change in Corneal Nerve Fibre Length in Diabetes Mellitus.
Author URL.
2017
Osigian CJ, Grace S, Cavuoto KM, Feuer WJ, Tavakoli M, Capo H, Lam BL (2017). Comparison of Non-Sedated Cone Flicker ERG Screening Test and Sedated Conventional ERG in Children.
Author URL.
Perkins BA, Lovblom LE, Bril V, Edwards K, Pritchard N, Russell A, Pacaud D, Romanchuk K, Mah J, Boulton AJM, et al (2017). Concurrent Diagnostic Validity of in Vivo Corneal Confocal Microscopy for the Diagnosis of Diabetic Polyneuropathy (DPN): a Pooled Multinational Analysis.
Author URL.
Alam U, Petropoulos IN, Fadavi H, Asghar O, Marshall A, Jeziorska M, Azmi S, Pritchard N, Ponirakis G, Edwards K, et al (2017). Corneal Confocal Microscopy Detects a Small-Fibre Neuropathy in Patients with LADA.
Author URL.
Tavakoli M, Soiland-Reyes C, Spencer R, Howard S, Boaden R (2017). Corneal Confocal Microscopy for Early Detection of Diabetic Neuropathy in Newly Diagnosed Patients with Type 2 Diabetes Mellitus.
Author URL.
Azmi S, Alam U, Ferdousi M, Petropoulos IN, Ponirakis G, Fadavi H, Asghar O, Marshall A, Jones W, Tavakoli M, et al (2017). Corneal Confocal Microscopy: a Viable Surrogate Endpoint for Neuropathy following Simultaneous Pancreas Kidney Transplant.
Author URL.
Alam U, Petropoulos IN, Fadavi H, Asghar O, Ponirakis G, Jeziorska M, Marshall A, Tavakoli M, Boulton AJM, Efron N, et al (2017). Corneal confocal microscopy detects improvements in small nerve fibres in subjects with latent autoimmune diabetes in adults with enhanced glycaemic control.
Author URL.
Tavakoli M, Yavuz DG, Tahrani AA, Selvarajah D, Bowling FL, Fadavi H (2017). Diabetic Neuropathy: Current Status and Future Prospects.
JOURNAL OF DIABETES RESEARCH,
2017 Author URL.
Alam U, Jeziorska M, Petropoulos IN, Asghar O, Fadavi H, Ponirakis G, Marshall A, Tavakoli M, Boulton AJM, Efron N, et al (2017). Diagnostic utility of corneal confocal microscopy and intra-epidermal nerve fibre density in diabetic neuropathy.
PLoS One,
12(7).
Abstract:
Diagnostic utility of corneal confocal microscopy and intra-epidermal nerve fibre density in diabetic neuropathy.
OBJECTIVES: Corneal confocal microscopy (CCM) is a rapid, non-invasive, reproducible technique that quantifies small nerve fibres. We have compared the diagnostic capability of CCM against a range of established measures of nerve damage in patients with diabetic neuropathy. METHODS: in this cross sectional study, thirty subjects with Type 1 diabetes without neuropathy (T1DM), thirty one T1DM subjects with neuropathy (DSPN) and twenty seven non-diabetic healthy control subjects underwent detailed assessment of neuropathic symptoms and neurologic deficits, quantitative sensory testing (QST), electrophysiology, skin biopsy and corneal confocal microscopy (CCM). RESULTS: Subjects with DSPN were older (C vs T1DM vs DSPN: 41.0±14.9 vs 38.8±12.5 vs 53.3±11.9, P = 0.0002), had a longer duration of diabetes (P
Abstract.
Author URL.
Tavakoli M (2017). Evaluation of clinical diagnostic markers for early detection of diabetic neuropathy.
Author URL.
Alahmar AT, Petropoulos IN, Ferdousi M, Jones W, Fadavi H, Azmi S, Alam U, Asghar O, Meskiri A, Kheyami A, et al (2017). Expression of skin Glyoxalase-I, advanced glycation end products (AGEs) and receptor (RAGE) in patients with long term type 1 diabetes and diabetic neuropathy.
Brunei International Medical Journal,
13(6), 180-193.
Abstract:
Expression of skin Glyoxalase-I, advanced glycation end products (AGEs) and receptor (RAGE) in patients with long term type 1 diabetes and diabetic neuropathy
Background: Certain group of diabetic patients have been shown to remain free of diabetic complications despite having had diabetes for longer periods. Advanced glycation end products (AGEs), their receptor (RAGE) and Glyoxalase-I (GLO-I) have been implicated in the development of diabetic neuropathy. Objective: to assess the effect of long term type 1 diabetes mellitus on skin distribution and expression of AGEs, RAGE and GLO-I and to correlate these expressions with measures of small and large nerve fibre damage. Methods: Sixty-seven patients with type 1 diabetes mellitus of shorter ( < 15 years, n=20), intermediate (15-40 years, n=25) and longer ( > 40 years, n=22) duration and 34 non-diabetic controls underwent diabetic neuropathy assessment: Neuropathy disability score (NDS), quantitative sensory testing (QST) including vibration pressure and thermal thresholds, nerve conduction studies (NCS), deep breathing heart rate variability (DB-HRV), corneal confocal microscopy (CCM) and intraepidermal nerve fibre density (IENFD) and AGEs, RAGE and GLO-I expression in foot skin biopsies. Results: Compared to controls, type 1 diabetes mellitus patients showed progressively increased skin expression of AGEs, RAGE but progressively lower GLO-I expression with increasing duration of diabetes. Thus patients with longerduration diabetes demonstrated significantly higher skin AGEs and RAGE but lower GLO-I expression than both shorter and intermediate duration diabetic groups. In patients with longer duration diabetes who developed diabetic neuropathy, the skin expression of AGEs and RAGE were significantly higher but GLO-I were significantly lower than those who did not develop diabetic neuropathy. These expressions also correlated with IENFD, CCM and NCS measures. Conclusion: Patients with type 1 diabetes mellitus showed progressively increased skin expression of AGEs, RAGE but progressively lower GLO-I expression with increasing duration of diabetes. Patients with longer duration diabetes who developed diabetic neuropathy have significantly higher skin AGEs and RAGE and decreased GLO-I expression suggesting a potential role for these macromolecules as aetiological, marker of the disease as well as therapeutic target for diabetic neuropathy.
Abstract.
Tavakoli M, Howard S, Soiland-Reyes C, Spencer R, Cotterill S, Perry C, Boaden R (2017). IMPLEMENTATION OF CORNEAL CONFOCAL MICROSCOPY FOR SCREENING DIABETIC NEUROPATHY IN PRIMARY CARE: a FEASIBILITY AND ACCEPTABILITY STUDY.
Author URL.
Kapetis D, Sassone J, Yang Y, Galbardi B, Xenakis MN, Westra RL, Szklarczyk R, Lindsey P, Faber CG, Gerrits M, et al (2017). Network topology of NaV1.7 mutations in sodium channel-related painful disorders. BMC Systems Biology, 11(1).
Tavakoli M, Manchester E-CG (2017). Screening and Early Detection of Diabetic Neuropathy in Newly Diagnosed Type 2 Diabetes Mellitus.
Author URL.
Azmi S, Jeziorska M, Ferdousi M, Petropoulos I, Ponirakis G, Marshall A, Alam U, Fadavi H, Tavakoli M, Asghar O, et al (2017). Simultaneous pancreas kidney transplantation in type 1 diabetes is associated with an early improvement in small fibres.
Author URL.
Azmi S, Ferdousi M, Alam U, Petropoulos IN, Ponirakis G, Marshall A, Asghar O, Fadavi H, Jones W, Tavakoli M, et al (2017). Small-fibre neuropathy in men with type 1 diabetes and erectile dysfunction: a cross-sectional study.
Diabetologia,
60(6), 1094-1101.
Abstract:
Small-fibre neuropathy in men with type 1 diabetes and erectile dysfunction: a cross-sectional study.
AIMS/HYPOTHESIS: the aim of this study was to identify the contribution of small- and large-fibre neuropathy to erectile dysfunction in men with type 1 diabetes mellitus. METHODS: a total of 70 participants (29 without and 41 with erectile dysfunction) with type 1 diabetes and 34 age-matched control participants underwent a comprehensive assessment of large- and small-fibre neuropathy. RESULTS: the prevalence of erectile dysfunction in participants with type 1 diabetes was 58.6%. After adjusting for age, participants with type 1 diabetes and erectile dysfunction had a significantly higher score on the Neuropathy Symptom Profile (mean ± SEM 5.3 ± 0.9 vs 1.8 ± 1.2, p = 0.03), a higher vibration perception threshold (18.3 ± 1.9 vs 10.7 ± 2.4 V, p = 0.02), and a lower sural nerve amplitude (5.0 ± 1.1 vs 11.7 ± 1.5 mV, p = 0.002), peroneal nerve amplitude (2.1 ± 0.4 vs 4.7 ± 0.5 mV, p
Abstract.
Author URL.
Marshall AG, Lee-Kubli C, Azmi S, Zhang M, Ferdousi M, Mixcoatl-Zecuatl T, Petropoulos IN, Ponirakis G, Fineman MS, Fadavi H, et al (2017). Spinal Disinhibition in Experimental and Clinical Painful Diabetic Neuropathy.
Diabetes,
66(5), 1380-1390.
Abstract:
Spinal Disinhibition in Experimental and Clinical Painful Diabetic Neuropathy.
Impaired rate-dependent depression (RDD) of the Hoffman reflex is associated with reduced dorsal spinal cord potassium chloride cotransporter expression and impaired spinal γ-aminobutyric acid type a receptor function, indicative of spinal inhibitory dysfunction. We have investigated the pathogenesis of impaired RDD in diabetic rodents exhibiting features of painful neuropathy and the translational potential of this marker of spinal inhibitory dysfunction in human painful diabetic neuropathy. Impaired RDD and allodynia were present in type 1 and type 2 diabetic rats but not in rats with type 1 diabetes receiving insulin supplementation that did not restore normoglycemia. Impaired RDD in diabetic rats was rapidly normalized by spinal delivery of duloxetine acting via 5-hydroxytryptamine type 2A receptors and temporally coincident with the alleviation of allodynia. Deficits in RDD and corneal nerve density were demonstrated in patients with painful diabetic neuropathy compared with healthy control subjects and patients with painless diabetic neuropathy. Spinal inhibitory dysfunction and peripheral small fiber pathology may contribute to the clinical phenotype in painful diabetic neuropathy. Deficits in RDD may help identify patients with spinally mediated painful diabetic neuropathy who may respond optimally to therapies such as duloxetine.
Abstract.
Author URL.
Tavakoli M, Fukashi Ishibashi, Rie Kojima, Miki Taniguchi, Aiko Kosaka, Harumi Uetake, Mitra Tavakoli (2017). The Preferential Impairment of Pupil Constriction Stimulated by Blue Light in Patients with Type 2 Diabetes without Autonomic Neuropathy. Journal of Diabetes Research
2016
Perkins BA, Lovblom LE, Bril V, Edwards K, Pritchard N, Russell A, Pacaud D, Romanchuk K, Mah J, Boulton A, et al (2016). 209 Results of an International Corneal Confocal Microscopy (CCM) Consortium: a Pooled Multicentre Analysis of the Concurrent Diagnostic Validity of CCM to Identify Diabetic Polyneuropathy in Type 2 Diabetes Mellitus. Canadian Journal of Diabetes, 40(5).
Perkins BA, Lovblom LE, Bril V, Edwards K, Pritchard N, Russell A, Pacaud D, Romanchuk K, Mah J, Boulton A, et al (2016). 59 Results of an International Corneal Confocal Microscopy (CCM) Consortium: a Pooled Multicentre Analysis of the Concurrent Diagnostic Validity of CCM to Identify Diabetic Polyneuropathy in Type 1 Diabetes Mellitus. Canadian Journal of Diabetes, 40(5).
Tavakoli M, Chen X, Graham J, Petropoulos I, Malik R (2016). An Automatic Tool for Quantification of Nerve Fibres in Corneal Confocal Microscopy Images. IEEE Trans Biomed Eng, 64, 786-794.
Sankar A, Fadavi H, Ferdousi M, Marshall A, Azmi S, Tavakoli M, Boulton AJM, Malik RA (2016). Corneal Confocal Microscopy Distinguishes between Painful and Painless Diabetic Peripheral Neuropathy.
Author URL.
Sankar A, Fadavi H, Ferdousi M, Marshall A, Azmi S, Tavakoli M, Boulton AJM, Malik RA (2016). Corneal confocal microscopy differentiates patients with painful from painless diabetic neuropathy.
Author URL.
Ponirakis G, Odriozola MN, Odriozola S, Petropoulos IN, Azmi S, Ferdousi M, Fadavi H, Alam U, Marshall A, Jeziorska M, et al (2016). NerveCheck for the Detection of Sensory Loss and Neuropathic Pain in Diabetes.
Diabetes Technol Ther,
18(12), 800-805.
Abstract:
NerveCheck for the Detection of Sensory Loss and Neuropathic Pain in Diabetes.
BACKGROUND: Accurate and economic detection of nerve damage in diabetes is key to more widespread diagnosis of patients with diabetic peripheral neuropathy (DPN) and painful diabetic neuropathy. This study examined the diagnostic performance of NerveCheck, an inexpensive ($500) quantitative sensory testing (QST) device. METHODS: One hundred forty-four subjects (74 with and 70 without diabetes) underwent assessment with NerveCheck, neuropathy disability score (NDS), nerve conduction studies (NCS), intraepidermal and corneal nerve fiber density (IENFD and CNFD), and McGill questionnaire for neuropathic pain. RESULTS: of the 74 subjects with diabetes, 41 were diagnosed with DPN based on the NDS. The NerveCheck scores for vibration perception threshold (VPT), cold perception threshold (CPT), and warm perception threshold (WPT) were significantly lower (P ≤ 0.0001) in diabetic patients with DPN compared to patients without DPN. The diagnostic accuracy of VPT was high with reference to NCS (area under the curve [AUC]: 82%-84%) and moderate for IENFD, CNFD, and neuropathic pain (AUC: 60%-76%). The diagnostic accuracy of CPT and WPT was moderate with reference to NCS, IENFD, and CNFD (AUC: 69%-78%) and low for neuropathic pain (AUC: 63%-65%). CONCLUSIONS: NerveCheck is a low-cost QST device with good diagnostic utility for identifying sensory deficits, comparable to established tests of large and small fiber neuropathy and for the severity of neuropathic pain.
Abstract.
Author URL.
Perini I, Tavakoli M, Marshall A, Minde J, Morrison I (2016). Rare human nerve growth factor-β mutation reveals relationship between C-afferent density and acute pain evaluation.
J Neurophysiol,
116(2), 425-430.
Abstract:
Rare human nerve growth factor-β mutation reveals relationship between C-afferent density and acute pain evaluation.
The rare nerve growth factor-β (NGFB) mutation R221W causes a selective loss of thinly myelinated fibers and especially unmyelinated C-fibers. Carriers of this mutation show altered pain sensation. A subset presents with arthropathic symptoms, with the homozygous most severely affected. The aim of the present study was to investigate the relationship between peripheral afferent loss and pain evaluation by performing a quantification of small-fiber density in the cornea of the carriers, relating density to pain evaluation measures. In vivo corneal confocal microscopy (CCM) was used to quantify C-fiber loss in the cornea of 19 R221W mutation carriers (3 homozygous) and 19 age-matched healthy control subjects. Pain evaluation data via the Situational Pain Questionnaire (SPQ) and the severity of neuropathy based on the Neuropathy Disability Score (NDS) were assessed. Homozygotes, heterozygotes, and control groups differed significantly in corneal C-nerve fiber density, with the homozygotes showing a significant afferent reduction. Importantly, peripheral C-fiber loss correlated negatively with pain evaluation, as revealed by SPQ scores. This study is the first to investigate the contribution of small-fiber density to the perceptual evaluation of pain. It demonstrates that the lower the peripheral small-fiber density, the lower the degree of reported pain intensity, indicating a functional relationship between small-fiber density and higher level pain experience.
Abstract.
Author URL.
Alahmar A, Petropoulos I, Ferdousi M, Jones W, Fadavi H, Azmi S, Alam U, Asghar O, Meskiri A, Kheyami A, et al (2016). Skin Expression of Advanced Glycation end Products (AGEs), Their Receptor (RAGE) and Glyoxalase-I (GLO-I) in Patients with Diabetic Neuropathy. British Journal of Medicine and Medical Research, 12(5), 1-13.
Ishibashi F, Kojima R, Taniguchi M, Kosaka A, Uetake H, Tavakoli M (2016). The Expanded Bead Size of Corneal C-Nerve Fibers Visualized by Corneal Confocal Microscopy is Associated with Slow Conduction Velocity of the Peripheral Nerves in Patients with Type 2 Diabetes Mellitus.
J Diabetes Res,
2016Abstract:
The Expanded Bead Size of Corneal C-Nerve Fibers Visualized by Corneal Confocal Microscopy is Associated with Slow Conduction Velocity of the Peripheral Nerves in Patients with Type 2 Diabetes Mellitus.
This study aims to establish the corneal nerve fiber (CNF) morphological alterations in a large cohort of type 2 diabetic patients and to investigate the association between the bead size, a novel parameter representing composite of accumulated mitochondria, glycogen particles, and vesicles in CNF, and the neurophysiological dysfunctions of the peripheral nerves. 162 type 2 diabetic patients and 45 healthy control subjects were studied in detail with a battery of clinical and neurological examinations and corneal confocal microscopy. Compared with controls, patients had abnormal CNF parameters. In particular the patients had reduced density and length of CNF and beading frequency and increased bead size. Alterations in CNF parameters were significant even in patients without neuropathy. The HbA1c levels were tightly associated with the bead size, which was inversely related to the motor and sensory nerve conduction velocity (NCV) and to the distal latency period of the median nerve positively. The CNF density and length positively correlated with the NCV and amplitude. The hyperglycemia-induced expansion of beads in CNF might be a predictor of slow NCV in peripheral nerves in type 2 diabetic patients.
Abstract.
Author URL.
2015
Tavakoli M, Malik R (2015). 8. The Acceptability and Feasibility of Corneal Confocal Microscopy to Detect Diabetic Neuropathy in Children: a Pilot Study (632-P). Nederlands Tijdschrift voor Diabetologie, 13(3), 61-62.
Tavakoli M, Ferdousi M, Petropoulos L, Morris J, Pritchard N, Romanchuk K, Pacaud D, Perkins BA, Brill V, Ziegler D, et al (2015). A Multinational Normative Dataset for Corneal Nerve Morphology Assessed Using Corneal Confocal Microscopy.
Author URL.
Tavakoli M, Ferdousi M, Petropoulos I, Morris J, Pritchard N, Zhivov A, Ziegler D, Pacaud D, Romanchuk K, Perkins B, et al (2015). A multi-national normative dataset for corneal nerve morphological parameters with using corneal confocal microscopy for early diagnosing diabetic neuropathy.
Author URL.
Ponirakis G, Fadavi H, Petropoulos IN, Azmi S, Ferdousi M, Dabbah MA, Kheyami A, Alam U, Asghar O, Marshall A, et al (2015). Automated Quantification of Neuropad Improves its Diagnostic Ability in Patients with Diabetic Neuropathy.
Journal of Diabetes Research,
2015, 1-7.
Abstract:
Automated Quantification of Neuropad Improves its Diagnostic Ability in Patients with Diabetic Neuropathy
Neuropad is currently a categorical visual screening test that identifies diabetic patients at risk of foot ulceration. The diagnostic performance of Neuropad was compared between the categorical and continuous (image-analysis (Sudometrics)) outputs to diagnose diabetic peripheral neuropathy (DPN). 110 subjects with type 1 and 2 diabetes underwent assessment with Neuropad, Neuropathy Disability Score (NDS), peroneal motor nerve conduction velocity (PMNCV), sural nerve action potential (SNAP), Deep Breathing-Heart Rate Variability (DB-HRV), intraepidermal nerve fibre density (IENFD), and corneal confocal microscopy (CCM). 46/110 patients had DPN according to the Toronto consensus. The continuous output displayed high sensitivity and specificity for DB-HRV (91%, 83%), CNFD (88%, 78%), and SNAP (88%, 83%), whereas the categorical output showed high sensitivity but low specificity. The optimal cut-off points were 90% for the detection of autonomic dysfunction (DB-HRV) and 80% for small fibre neuropathy (CNFD). The diagnostic efficacy of the continuous Neuropad output for abnormal DB-HRV (AUC: 91%,P=0.0003) and CNFD (AUC: 82%,P=0.01) was better than for PMNCV (AUC: 60%). The categorical output showed no significant difference in diagnostic efficacy for these same measures. An image analysis algorithm generating a continuous output (Sudometrics) improved the diagnostic ability of Neuropad, particularly in detecting autonomic and small fibre neuropathy.
Abstract.
Bagheri A, Borhani M, Salehirad S, Yazdani S, Tavakoli M (2015). Blepharoptosis Associated with Third Cranial Nerve Palsy. Ophthalmic Plastic & Reconstructive Surgery, 31(5), 357-360.
Petropoulos IN, Green P, Chan AWS, Alam U, Fadavi H, Marshall A, Asghar O, Efron N, Tavakoli M, Malik RA, et al (2015). Corneal Confocal Microscopy Detects Neuropathy in Patients with Type 1 Diabetes without Retinopathy or Microalbuminuria. PLOS ONE, 10(4), e0123517-e0123517.
Ferdousi M, Azmi S, Petropoulos IN, Fadavi H, Ponirakis G, Marshall A, Tavakoli M, Malik I, Mansoor W, Malik RA, et al (2015). Corneal Confocal Microscopy Detects Small Fibre Neuropathy in Patients with Upper Gastrointestinal Cancer and Nerve Regeneration in Chemotherapy Induced Peripheral Neuropathy. PLOS ONE, 10(10), e0139394-e0139394.
Azmi S, Ferdousi M, Petropoulos IN, Ponirakis G, Alam U, Fadavi H, Asghar O, Marshall A, Atkinson AJ, Jones W, et al (2015). Corneal Confocal Microscopy Identifies Small-Fiber Neuropathy in Subjects with Impaired Glucose Tolerance Who Develop Type 2 Diabetes.
Diabetes Care,
38(8), 1502-1508.
Abstract:
Corneal Confocal Microscopy Identifies Small-Fiber Neuropathy in Subjects with Impaired Glucose Tolerance Who Develop Type 2 Diabetes
. OBJECTIVE
. Impaired glucose tolerance (IGT) through to type 2 diabetes is thought to confer a continuum of risk for neuropathy. Identification of subjects at high risk of developing type 2 diabetes and, hence, worsening neuropathy would allow identification and risk stratification for more aggressive management.
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. RESEARCH DESIGN AND METHODS
. Thirty subjects with IGT and 17 age-matched control subjects underwent an oral glucose tolerance test, assessment of neuropathic symptoms and deficits, quantitative sensory testing, neurophysiology, skin biopsy, and corneal confocal microscopy (CCM) to quantify corneal nerve fiber density (CNFD), branch density (CNBD), and fiber length (CNFL) at baseline and annually for 3 years.
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. RESULTS
. Ten subjects who developed type 2 diabetes had a significantly lower CNFD (P = 0.003), CNBD (P = 0.04), and CNFL (P = 0.04) compared with control subjects at baseline and a further reduction in CNFL (P = 0.006), intraepidermal nerve fiber density (IENFD) (P = 0.02), and mean dendritic length (MDL) (P = 0.02) over 3 years. Fifteen subjects who remained IGT and 5 subjects who returned to normal glucose tolerance had no significant baseline abnormality on CCM or IENFD but had a lower MDL (P &lt; 0.0001) compared with control subjects. The IGT subjects showed a significant decrease in IENFD (P = 0.02) but no change in MDL or CCM over 3 years. Those who returned to NGT showed an increase in CNFD (P = 0.05), CNBD (P = 0.04), and CNFL (P = 0.05), but a decrease in IENFD (P = 0.02), over 3 years.
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. CONCLUSIONS
. CCM and skin biopsy detect a small-fiber neuropathy in subjects with IGT who develop type 2 diabetes and also show a dynamic worsening or improvement in corneal and intraepidermal nerve morphology in relation to change in glucose tolerance status.
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Abstract.
Javed S, Ponirakis G, Ferdousi M, Azmi S, Petropoulos I, Tavakoli M, Jeziorska M, Gosal D, Malik RA (2015). Corneal confocal microscopy detects small-fibre damage, particularly in patients with sensory and autonomic ISFN.
Author URL.
Tavakoli M, Begum P, McLaughlin J, Malik RA (2015). Corneal confocal microscopy for the diagnosis of diabetic autonomic neuropathy. Muscle & Nerve, 52(3), 363-370.
Alam U, Asghar O, Petropoulos IN, Jeziorska M, Fadavi H, Ponirakis G, Marshall A, Tavakoli M, Boulton AJM, Efron N, et al (2015). Erratum. Small Fiber Neuropathy in Patients with Latent Autoimmune Diabetes in Adults. Diabetes Care 2015;38:e102–e103. Diabetes Care, 38(10), 1992.2-1992.
Lagali N, Poletti E, Patel DV, McGhee CNJ, Hamrah P, Kheirkhah A, Tavakoli M, Petropoulos IN, Malik RA, Utheim TP, et al (2015). Focused Tortuosity Definitions Based on Expert Clinical Assessment of Corneal Subbasal Nerves. Investigative Opthalmology & Visual Science, 56(9), 5102-5102.
Tavakoli M, Ferdousi M, Petropoulos I, Fadavi H, Boulton AJM, Malik R (2015). NEURO - DEGENERATION OF CORNEA AND RETINA IN PATIENTS WITH TYPE 1 DIABETES WITHOUT CLINICAL EVIDENCE OF DIABETIC RETINOPATHY AND NEUROPATHY.
Author URL.
Tavakoli M, Ferdousi M, Petropoulos IN, Morris J, Pritchard N, Zhivov A, Ziegler D, Pacaud D, Romanchuk K, Perkins BA, et al (2015). Normative Values for Corneal Nerve Morphology Assessed Using Corneal Confocal Microscopy: a Multinational Normative Data Set.
Diabetes Care,
38(5), 838-843.
Abstract:
Normative Values for Corneal Nerve Morphology Assessed Using Corneal Confocal Microscopy: a Multinational Normative Data Set
. OBJECTIVE
. Corneal confocal microscopy is a novel diagnostic technique for the detection of nerve damage and repair in a range of peripheral neuropathies, in particular diabetic neuropathy. Normative reference values are required to enable clinical translation and wider use of this technique. We have therefore undertaken a multicenter collaboration to provide worldwide age-adjusted normative values of corneal nerve fiber parameters.
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.
. RESEARCH DESIGN AND METHODS
. A total of 1,965 corneal nerve images from 343 healthy volunteers were pooled from six clinical academic centers. All subjects underwent examination with the Heidelberg Retina Tomograph corneal confocal microscope. Images of the central corneal subbasal nerve plexus were acquired by each center using a standard protocol and analyzed by three trained examiners using manual tracing and semiautomated software (CCMetrics). Age trends were established using simple linear regression, and normative corneal nerve fiber density (CNFD), corneal nerve fiber branch density (CNBD), corneal nerve fiber length (CNFL), and corneal nerve fiber tortuosity (CNFT) reference values were calculated using quantile regression analysis.
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. RESULTS
. There was a significant linear age-dependent decrease in CNFD (−0.164 no./mm2 per year for men, P &lt; 0.01, and −0.161 no./mm2 per year for women, P &lt; 0.01). There was no change with age in CNBD (0.192 no./mm2 per year for men, P = 0.26, and −0.050 no./mm2 per year for women, P = 0.78). CNFL decreased in men (−0.045 mm/mm2 per year, P = 0.07) and women (−0.060 mm/mm2 per year, P = 0.02). CNFT increased with age in men (0.044 per year, P &lt; 0.01) and women (0.046 per year, P &lt; 0.01). Height, weight, and BMI did not influence the 5th percentile normative values for any corneal nerve parameter.
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. CONCLUSIONS
. This study provides robust worldwide normative reference values for corneal nerve parameters to be used in research and clinical practice in the study of diabetic and other peripheral neuropathies.
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Abstract.
Azmi S, Ferdousi M, Ponirakis G, Petropoulos I, Schofield J, Fadavi H, Tavakoli M, Soran H, Malik RA (2015). Obesity related neuropathy and the effects of bariatric surgery.
Author URL.
Azmi S, Ferdousi M, Ponirakis G, Alam U, Petropoulos I, Marshall A, Tavakoli M, Ammori B, Soran H, Malik R, et al (2015). Obesity related neuropathy and the effects of bariatric surgery.
Author URL.
Azmi S, Ferdousi M, Ponirakis G, Petropoulos IN, Alam U, Tavakoli M, Fadavi H, Schofield J, Siahmansur T, Marshall A, et al (2015). Obesity-related Neuropathy and the Effects of Bariatric Surgery.
Author URL.
Petropoulos IN, Tavakoli M, Marshall A, Malik RA (2015). Response to Comment on Malik. Which Test for Diagnosing Early Human Diabetic Neuropathy? Diabetes 2014;63:2206–2208. Diabetes, 64(2), e2-e3.
Alam U, Asghar O, Petropoulos IN, Jeziorska M, Fadavi H, Ponirakis G, Marshall A, Tavakoli M, Boulton AJM, Efron N, et al (2015). Small Fiber Neuropathy in Patients with Latent Autoimmune Diabetes in Adults. Diabetes Care, 38(7), e102-e103.
Chen X, Graham J, Dabbah MA, Petropoulos IN, Ponirakis G, Asghar O, Alam U, Marshall A, Fadavi H, Ferdousi M, et al (2015). Small Nerve Fiber Quantification in the Diagnosis of Diabetic Sensorimotor Polyneuropathy: Comparing Corneal Confocal Microscopy with Intraepidermal Nerve Fiber Density.
Diabetes Care,
38(6), 1138-1144.
Abstract:
Small Nerve Fiber Quantification in the Diagnosis of Diabetic Sensorimotor Polyneuropathy: Comparing Corneal Confocal Microscopy with Intraepidermal Nerve Fiber Density
. OBJECTIVE
. Quantitative assessment of small fiber damage is key to the early diagnosis and assessment of progression or regression of diabetic sensorimotor polyneuropathy (DSPN). Intraepidermal nerve fiber density (IENFD) is the current gold standard, but corneal confocal microscopy (CCM), an in vivo ophthalmic imaging modality, has the potential to be a noninvasive and objective image biomarker for identifying small fiber damage. The purpose of this study was to determine the diagnostic performance of CCM and IENFD by using the current guidelines as the reference standard.
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. RESEARCH DESIGN AND METHODS
. Eighty-nine subjects (26 control subjects and 63 patients with type 1 diabetes), with and without DSPN, underwent a detailed assessment of neuropathy, including CCM and skin biopsy.
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.
. RESULTS
. Manual and automated corneal nerve fiber density (CNFD) (P &lt; 0.0001), branch density (CNBD) (P &lt; 0.0001) and length (CNFL) (P &lt; 0.0001), and IENFD (P &lt; 0.001) were significantly reduced in patients with diabetes with DSPN compared with control subjects. The area under the receiver operating characteristic curve for identifying DSPN was 0.82 for manual CNFD, 0.80 for automated CNFD, and 0.66 for IENFD, which did not differ significantly (P = 0.14).
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. CONCLUSIONS
. This study shows comparable diagnostic efficiency between CCM and IENFD, providing further support for the clinical utility of CCM as a surrogate end point for DSPN.
.
Abstract.
Kass-Iliyya L, Javed S, Gosal D, Kobylecki C, Marshall A, Petropoulos IN, Ponirakis G, Tavakoli M, Ferdousi M, Chaudhuri KR, et al (2015). Small fiber neuropathy in Parkinson's disease: a clinical, pathological and corneal confocal microscopy study. Parkinsonism & Related Disorders, 21(12), 1454-1460.
Tavakoli M, Malik R (2015). The Acceptability and Feasibility of Corneal Confocal Microscopy to Detect Diabetic Neuropathy in Children: a Pilot Study.
Author URL.
Ponirakis G, Odriozola M, Petropoulos IN, Azmi S, Ferdousi M, Fadavi H, Alam U, Asghar O, Mashall A, Tavakoli M, et al (2015). The Diagnostic Validity of Nervecheck: from Functional and Structural Damage of Small and Large Nerve Fibres to Neuropathic Pain.
Author URL.
Petropoulos IN, Ferdousi M, Marshall A, Alam U, Ponirakis G, Azmi S, Fadavi H, Efron N, Tavakoli M, Malik RA, et al (2015). The Inferior Whorl for Detecting Diabetic Peripheral Neuropathy Using Corneal Confocal Microscopy. Investigative Opthalmology & Visual Science, 56(4), 2498-2498.
Pacaud D, Romanchuk KG, Tavakoli M, Gougeon C, Virtanen H, Ferdousi M, Nettel-Aguirre A, Mah JK, Malik RA (2015). The Reliability and Reproducibility of Corneal Confocal Microscopy in Children. Investigative Opthalmology & Visual Science, 56(9), 5636-5636.
2014
Javed S, Petropoulos IN, Tavakoli. M, Malik RA, Tavakoli M (2014). Chapter 20: Clinical and diagnostic features of small fiber damage in diabetic polyneuropathy. In (Ed) Handbook of Clinical Neurology
Diabetes and the Nervous System, Elsevier B.V, 275-290.
Tavakoli M (2014). Chapter 3: Neuropatia de fibra fina: novas abordagens diagnósticas. In Hermelinda C. Pedrosa, Lucio Vilar, Andrew J. M. Boulton (Eds.)
Neuropatias e Pé Diabético.
Abstract:
Chapter 3: Neuropatia de fibra fina: novas abordagens diagnósticas
Abstract.
Javed S, Petropoulos IN, Tavakoli M, Malik RA (2014). Clinical and diagnostic features of small fiber damage in diabetic polyneuropathy.
Handb Clin Neurol,
126, 275-290.
Abstract:
Clinical and diagnostic features of small fiber damage in diabetic polyneuropathy.
Small fiber neuropathy represents a significant component of diabetic sensorimotor polyneuropathy (DSPN) which has to date been ignored in most recommendations for the diagnosis of DSPN. Small fibers predominate in the peripheral nerve, serve crucial and highly clinically relevant functions such as pain, and regulate microvascular blood flow, mediating the mechanisms underlying foot ulceration. An increasing number of diagnostic tests have been developed to quantify small fiber damage. Because small fiber damage precedes large fiber damage, diagnostic tests for DSPN show good sensitivity but moderate specificity, because the gold standard which is used to define DSPN is large fiber-weighted. Hence new diagnostic algorithms for DSPN should acknowledge this emerging data and incorporate small fiber evaluation as a key measure in the diagnosis of DSPN, especially early neuropathy.
Abstract.
Author URL.
Azmi S, Ponirakis G, Ferdousi M, Petropoulos IN, Alam U, Marshall A, Kheyami A, Fadavi H, Tavakoli M, Boulton AJM, et al (2014). Corneal Confocal Microscopy (CCM) Detects an Improvement in Small Fibre Neuropathy in Subjects with Type 1 Diabetes Mellitus (T1DM) on Continuous Subcutaneous Insulin Infusion (CSII).
Author URL.
Alam U, Azmi S, Ferdousi M, Petropoulos IN, Ponirakis G, Fadavi H, Tavakoli M, Marshall A, Boulton AJM, Malik RA, et al (2014). Corneal Confocal Microscopy (CCM) Identifies Early Small Fibre Neuropathy and Predicts the Development of Microalbuminuria in Type 1 Diabetes (T1DM).
Author URL.
Asghar O, Petropoulos IN, Alam U, Jones W, Jeziorska M, Marshall A, Ponirakis G, Fadavi H, Boulton AJM, Tavakoli M, et al (2014). Corneal Confocal Microscopy Detects Neuropathy in Subjects with Impaired Glucose Tolerance.
Diabetes Care,
37(9), 2643-2646.
Abstract:
Corneal Confocal Microscopy Detects Neuropathy in Subjects with Impaired Glucose Tolerance
. OBJECTIVE
. Impaired glucose tolerance (IGT) represents one of the earliest stages of glucose dysregulation and is associated with macrovascular disease, retinopathy, and microalbuminuria, but whether IGT causes neuropathy is unclear.
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. RESEARCH DESIGN AND METHODS
. Thirty-seven subjects with IGT and 20 age-matched control subjects underwent a comprehensive evaluation of neuropathy by assessing symptoms, neurological deficits, nerve conduction studies, quantitative sensory testing, heart rate variability deep breathing (HRVdb), skin biopsy, and corneal confocal microscopy (CCM).
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. RESULTS
. Subjects with IGT had a significantly increased neuropathy symptom profile (P &lt; 0.001), McGill pain index (P &lt; 0.001), neuropathy disability score (P = 0.001), vibration perception threshold (P = 0.002), warm threshold (P = 0.006), and cool threshold (P = 0.03), with a reduction in intraepidermal nerve fiber density (P = 0.03), corneal nerve fiber density (P &lt; 0.001), corneal nerve branch density (P = 0.002), and corneal nerve fiber length (P = 0.05). No significant difference was found in sensory and motor nerve amplitude and conduction velocity or HRVdb.
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. CONCLUSIONS
. Subjects with IGT have evidence of neuropathy, particularly small-fiber damage, which can be detected using skin biopsy and CCM.
.
Abstract.
Azmi S, Ferdousi M, Petropoulos IN, Ponirakis G, Fadavi H, Tavakoli M, Alam U, Jones W, Marshall A, Jeziorska M, et al (2014). Corneal Confocal Microscopy Shows an Improvement in Small-Fiber Neuropathy in Subjects with Type 1 Diabetes on Continuous Subcutaneous Insulin Infusion Compared with Multiple Daily Injection. Diabetes Care, 38(1), e3-e4.
Tavakoli M, Begum P, Malik RA, Mclaughlin J (2014). Corneal Confocal Microscopy for the Diagnosis of Autonomic Neuropathy in Diabetic Gastroenteropathy.
Author URL.
Pacaud D, Romanchuk K, Tavakoli M, Gougeon C, Ferdousi M, Mah JK, Nettel-Aguirre A, Malik RA (2014). Corneal Confocal Microscopy in Children with Type 1 Diabetes: Interobserver Agreement and Repeatability of Nerve Fiber Length Measurements.
Author URL.
Azmi S, Petropoulos I, Ferdousi MF, Ponirakis G, Alam U, Fadavi HF, Tavakoli M, Kheyami A, Jeziorska M, Malik RA, et al (2014). Corneal confocal microscopy detects early nerve damage in subjects with impaired glucose tolerance and predicts progression to diabetes.
Author URL.
Ponirakis G, Petropoulos I, Fadavi HF, Uazman AU, Asghar OA, Jeziorska M, Ferdousi MF, Marshall AM, Tavakoli M, Malik RAM, et al (2014). Corneal confocal microscopy: a prognostic test for the development of diabetic neuropathy.
Author URL.
Alam U, Petropoulos IN, Asghar O, Azmi S, Fadavi H, Marshall A, Tavakoli M, Boulton AJM, Efron N, Malik RA, et al (2014). Diabetic Neuropathy in Patients with Latent Autoimmune Diabetes in Adults (LADA).
Author URL.
Pritchard N, Edwards K, Dehghani C, Fadavi H, Jeziorska M, Marshall A, Petropoulos IN, Ponirakis G, Russell AW, Sampson GP, et al (2014). Longitudinal assessment of neuropathy in type 1 diabetes using novel ophthalmic markers (LANDMark): Study design and baseline characteristics. Diabetes Research and Clinical Practice, 104(2), 248-256.
Tavakoli M, Ferdousi M, Petropoulos IN, Fadavi H, Marshall A, Boulton AJM, Malik RA (2014). Ophthalmic biomarkers of diabetic neuropathy: does neural dysfunction precede vascular changes?.
Author URL.
Tavakoli M, Fadavi H, Malik RA (2014). Optimal Measures of Small Fiber Neuropathy in Diabetic Polyneuropathy. In (Ed)
Studies in Diabetes, Springer Science & Business Media, 93-105.
Abstract:
Optimal Measures of Small Fiber Neuropathy in Diabetic Polyneuropathy.
Abstract.
Petropoulos IN, Alam U, Fadavi H, Marshall A, Asghar O, Dabbah MA, Chen X, Graham J, Ponirakis G, Boulton AJM, et al (2014). Rapid Automated Diagnosis of Diabetic Peripheral Neuropathy with in Vivo Corneal Confocal Microscopy. Investigative Opthalmology & Visual Science, 55(4), 2071-2071.
Tavakoli M, Ferdousi M, Petropoulos I, Malik R (2014). Retinal and Corneal neural dysfunction precedes retinopathy and correlates with peripheral neuropathy in patients with Type 1 diabetes.
Author URL.
Alahmar A, Fadavi H, Alam U, Asghar O, Petropoulos IN, Ferdousi M, Ponirakis G, Meskiri A, Jones W, Azmi S, et al (2014). Skin AGE/RAGE Expression is Related to the Severity of Diabetic Neuropathy.
Author URL.
Ponirakis G, Petropoulos IN, Fadavi H, Alam U, Asghar O, Marshall A, Tavakoli M, Malik RA (2014). The diagnostic accuracy of Neuropad<sup>®</sup>for assessing large and small fibre diabetic neuropathy. Diabetic Medicine, 31(12), 1673-1680.
2013
Alam U, Petropoulos IN, Fadavi H, Asghar O, Marshall A, Ponirakis G, Al-Ahmar A, Kheyami A, Ferdousi M, Azmi S, et al (2013). Corneal Confocal Microscopy is as Proficient as Electrophysiology and Skin Biopsy in Detecting Neuropathy in Subjects with Type 1 Diabetes Mellitus.
Author URL.
Tavakoli M, Malik R (2013). Corneal Confocal Microscopy detects neuropathy before retinopathy and nephropathy in children with Type 1 Diabetes: a Preliminary Study.
Author URL.
Petropoulos IN, Alam U, Fadavi H, Asghar O, Green P, Ponirakis G, Marshall A, Boulton AJM, Tavakoli M, Malik RA, et al (2013). Corneal Nerve Loss Detected with Corneal Confocal Microscopy is Symmetrical and Related to the Severity of Diabetic Polyneuropathy.
Diabetes Care,
36(11), 3646-3651.
Abstract:
Corneal Nerve Loss Detected with Corneal Confocal Microscopy is Symmetrical and Related to the Severity of Diabetic Polyneuropathy
. OBJECTIVE
. To establish if corneal nerve loss, detected using in vivo corneal confocal microscopy (IVCCM), is symmetrical between right and left eyes and relates to the severity of diabetic neuropathy.
.
.
. RESEARCH DESIGN AND METHODS
. Patients (n = 111) with type 1 and type 2 diabetes and 47 age-matched healthy control subjects underwent detailed assessment and stratification into no (n = 50), mild (n = 26), moderate (n = 17), and severe (n = 18) neuropathy. IVCCM was performed in both eyes and corneal nerve fiber density (CNFD), branch density (CNBD), and fiber length (CNFL) and the tortuosity coefficient were quantified.
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. RESULTS
. All corneal nerve parameters differed significantly between diabetic patients and control subjects and progressively worsened with increasing severity of neuropathy. The reduction in CNFD, CNBD, and CNFL was symmetrical in all groups except in patients with severe neuropathy.
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. CONCLUSIONS
. IVCCM noninvasively detects corneal nerve loss, which relates to the severity of neuropathy, and is symmetrical, except in those with severe diabetic neuropathy.
.
Abstract.
Petropoulos IN, Asghar O, Alam U, Fadavi H, Ponirakis G, Marshall A, Tavakoli M, Boulton AJM, Malik RA (2013). Corneal confocal microscopy detects and tracks progression of neuropathy in subjects with impaired glucose tolerance.
Author URL.
Tavakoli M, Mitu-Pretorian M, Petropoulos IN, Fadavi H, Asghar O, Alam U, Ponirakis G, Jeziorska M, Marshall A, Boulton AJM, et al (2013). Corneal confocal microscopy detects early nerve regeneration in diabetic neuropathy following simultaneous pancreas and kidney transplantation.
Author URL.
Tavakoli M, Malik RA (2013). Corneal confocal microscopy detects neuropathy before retinopathy and nephropathy in children with type 1 diabetes: a preliminary study.
Author URL.
Tavakoli M, Petropoulos IN, Malik RA (2013). Corneal confocal microscopy to assess diabetic neuropathy: an eye on the foot.
J Diabetes Sci Technol,
7(5), 1179-1189.
Abstract:
Corneal confocal microscopy to assess diabetic neuropathy: an eye on the foot.
Accurate detection and quantification of human diabetic peripheral neuropathy are important to define at-risk patients, anticipate deterioration, and assess new therapies. Easily performed clinical techniques such as neuro-logical examination, assessment of vibration perception or insensitivity to the 10 g monofilament only assess advanced neuropathy, i.e. the at-risk foot. Techniques that assess early neuropathy include neurophysiology (which assesses only large fibers) and quantitative sensory testing (which assesses small fibers), but they can be highly subjective while more objective techniques, such as skin biopsy for intra-epidermal nerve fiber density quantification, are invasive and not widely available. The emerging ophthalmic technique of corneal confocal microscopy allows quantification of corneal nerve morphology and enables clinicians to diagnose peripheral neuropathy in diabetes patients, quantify its severity, and potentially assess therapeutic benefit. The present review provides a detailed critique of the rationale, a practical approach to capture images, and a basis for analyzing and interpreting the images. We also critically evaluate the diagnostic ability of this new noninvasive ophthalmic test to diagnose diabetic and other peripheral neuropathies.
Abstract.
Author URL.
Tavakoli M (2013). Corneal confocal microscopy: Beyond corneal defects! Translational studies in diabetes and neurology. Contact Lens and Anterior Eye, 36, e1-e1.
Ponirakis G, Petropoulos IP, Fadavi H, Alam UA, Asghar OA, Tavakoli M, Malik RAM (2013). Diagnostic performance of Neuropad response.
Author URL.
Azmi S, Alam U, Fadavi H, Asghar O, Petropoulos IN, Ponirakis G, Marshall A, Ferdousi M, Kheyami A, Alahmar A, et al (2013). Early Non-Progressive Small Fibre Neuropathy in Type 2 Diabetes.
Author URL.
Efron N, Pritchard N, Edwards K, Sampson G, Russell A, Petropoulos I, Alam U, Fadavi H, Tavakoli M, Malik R, et al (2013). Longitudinal Assessment of Neuropathy in Diabetes using novel ophthalmic MARKers (LANDMark): Baseline findings.
Author URL.
Alimohammadi S, Hobbenaghi R, Javanbakht J, Kheradmand D, Mortezaee R, Tavakoli M, Khadivar F, Akbari H (2013). Protective and antidiabetic effects of extract from Nigella sativa on blood glucose concentrations against streptozotocin (STZ)-induced diabetic in rats: an experimental study with histopathological evaluation.
Diagn Pathol,
8Abstract:
Protective and antidiabetic effects of extract from Nigella sativa on blood glucose concentrations against streptozotocin (STZ)-induced diabetic in rats: an experimental study with histopathological evaluation.
BACKGROUND: Diabetes in humans induces chronic complications such as cardiovascular damage, cataracts and retinopathy, nephropathy and polyneuropathy. The most common animal model of human diabetes is streptozotocin (STZ)-induced diabetes in the rat. The present study investigated the effects of Nigella sativa hydroalcholic extract on glucose concentrations in streptozotocin (STZ) diabetic rats. METHODS: in this study Twenty-five Wister-Albino rats (aged 8-9 weeks and weighing 200-250 g) were tested. Rats were divided into five experimental groups (control, untreated STZ-diabetic (60 mg/kg B.W. IP), treated STZ-diabetic with hydroalcholic extract of Nigella Sativa (NS) (5 mg/kg B.W, IP), treated STZ-diabetic with hydroalcholic extract of NS (10 mg/kg B.W. IP) and treated STZ-diabetic with hydroalcholic extract of NS (20 mg/kg B.W. IP and 32 days were evaluated to assess its effect on fasting blood glucose (FBG), and in different groups fasting blood glucose (FBG) and body weight (BW) were measured in the particular days (1, 16 and 32). At the end of the study, the animals were fasted overnight, anaesthetized with an intraperitoneal injection of sodium pentobarbital (60 mg/kg), and sacrificed for obtaining tissues samples (liver, pancreases). The number of islets and cells were counted and the islet diameters were determined by calibrated micrometer. The glycogen content in the liver was examined by Periodic Acid-Schiff (PAS) staining. RESULTS: Treatment with NS (5 mg/kg b.w.) markedly increased BW gain and the FBG level was significantly (p
Abstract.
Author URL.
Petropoulos IN, Manzoor T, Morgan P, Fadavi H, Asghar O, Alam U, Ponirakis G, Dabbah MA, Chen X, Graham J, et al (2013). Repeatability of in Vivo Corneal Confocal Microscopy to Quantify Corneal Nerve Morphology. Cornea, 32(5), e83-e89.
Safiarian R, Amini P, Moez EK, Mohammadzadeh F, Tavakoli M, Zayeri F (2013). Risk group classification for bleeding after coronary artery bypass graft surgery: a comparison of the logistic regression with decision tree models.
TURK GOGUS KALP DAMAR CERRAHISI DERGISI-TURKISH JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY,
21(3), 574-580.
Author URL.
Khambalia H, Tavakoli M, Moinuddin Z, van Dellen D, Malik R, Augustine T (2013). Simultaneous Pancreas and Kidney Transplantation leads to Early Nerve Regeneration, as Evaluated by Corneal Confocal Microscopy.
Author URL.
Sellers EAC, Clark I, Tavakoli M, Dean HJ, McGavock J, Malik RA (2013). The acceptability and feasibility of corneal confocal microscopy to detect early diabetic neuropathy in children: a pilot study. Diabetic Medicine, 30(5), 630-631.
2012
Tavakoli M, Mitu-Pretorian M, Petropoulos IN, Fadavi H, Asghar O, Alam U, Ponirakis G, Jeziorska M, Marshall A, Efron N, et al (2012). Corneal Confocal Microscopy Detects Early Nerve Regeneration in Diabetic Neuropathy After Simultaneous Pancreas and Kidney Transplantation.
Diabetes,
62(1), 254-260.
Abstract:
Corneal Confocal Microscopy Detects Early Nerve Regeneration in Diabetic Neuropathy After Simultaneous Pancreas and Kidney Transplantation
Diabetic neuropathy is associated with increased morbidity and mortality. To date, limited data in subjects with impaired glucose tolerance and diabetes demonstrate nerve fiber repair after intervention. This may reflect a lack of efficacy of the interventions but may also reflect difficulty of the tests currently deployed to adequately assess nerve fiber repair, particularly in short-term studies. Corneal confocal microscopy (CCM) represents a novel noninvasive means to quantify nerve fiber damage and repair. Fifteen type 1 diabetic patients undergoing simultaneous pancreas–kidney transplantation (SPK) underwent detailed assessment of neurologic deficits, quantitative sensory testing (QST), electrophysiology, skin biopsy, corneal sensitivity, and CCM at baseline and at 6 and 12 months after successful SPK. At baseline, diabetic patients had a significant neuropathy compared with control subjects. After successful SPK there was no significant change in neurologic impairment, neurophysiology, QST, corneal sensitivity, and intraepidermal nerve fiber density (IENFD). However, CCM demonstrated significant improvements in corneal nerve fiber density, branch density, and length at 12 months. Normalization of glycemia after SPK shows no significant improvement in neuropathy assessed by the neurologic deficits, QST, electrophysiology, and IENFD. However, CCM shows a significant improvement in nerve morphology, providing a novel noninvasive means to establish early nerve repair that is missed by currently advocated assessment techniques.
Abstract.
Tavakoli M, Marshall A, Banka S, Petropoulos IN, Fadavi H, Kingston H, Malik RA (2012). Corneal confocal microscopy detects small-fiber neuropathy in Charcot-Marie-Tooth disease type 1A patients. Muscle & Nerve, 46(5), 698-704.
Razmju H, Akhlaghi MR, Tavakoli M (2012). Evaluation of intravitreal injection of bevacizumab (Avastin) in treatment of diabetic macular edema in patients referring to Feiz Eye Hospital, Isfahan, Iran.
JOURNAL OF RESEARCH IN MEDICAL SCIENCES,
17, S79-S82.
Author URL.
Alam U, Petropoulos I, Fadavi H, Asghar O, Marshall A, Ponirakis G, Tavakoli M, Boulton AJ, Malik R (2012). Small Fibre Dysfunction and Vitamin D Deficiency Underlie Painful Diabetic Neuropathy.
Author URL.
2011
Tavakoli M, Toosi MHB, Pourreza R, Banaee T, Pourreza HR, IEEE (2011). Automated Optic Nerve Head Detection in Fluorescein Angiography Fundus Images.
Author URL.
Dabbah MA, Graham J, Petropoulos IN, Tavakoli M, Malik RA (2011). Automatic analysis of diabetic peripheral neuropathy using multi-scale quantitative morphology of nerve fibres in corneal confocal microscopy imaging. Medical Image Analysis, 15(5), 738-747.
Asghar O, Petropoulos IN, Alam U, Ponirakis G, Fadavi H, Marshall A, Tavakoli M, Boulton AJM, Malik RA (2011). Corneal Confocal Microscopy Detects Neuropathy in Impaired Glucose Tolerance.
Author URL.
Tavakoli M, Malik RA (2011). Corneal Confocal Microscopy: a Novel Non-invasive Technique to Quantify Small Fibre Pathology in Peripheral Neuropathies. Journal of Visualized Experiments(47).
Tavakoli M, Malik RA (2011). Corneal Confocal Microscopy: a Novel Non-invasive Technique to Quantify Small Fibre Pathology in Peripheral Neuropathies. Journal of Visualized Experiments(47).
Tavakoli M, Kallinikos P, Iqbal A, Herbert A, Fadavi H, Efron N, Boulton AJM, a Malik R (2011). Corneal confocal microscopy detects improvement in corneal nerve morphology with an improvement in risk factors for diabetic neuropathy. Diabetic Medicine, 28(10), 1261-1267.
Tavakoli M, Petropoulos I, Fadavi H, Alam U, Asghar O, Ponirakis G, Boulton AJM, Malik RA (2011). Corneal nerve fibre damage defined using corneal confocal microscopy in relation to tear film proteomics.
Author URL.
Tavakoli M, Boulton AJM, Efron N, Malik RA (2011). Increased Langerhan cell density and corneal nerve damage in diabetic patients: Role of immune mechanisms in human diabetic neuropathy. Contact Lens and Anterior Eye, 34(1), 7-11.
Fadavi H, Tavakoli M, Petropolous IN, Caturvedi N, Jeziorska M, Boulton AJM, Malik RA, Abbott CA (2011). Potential explanation for lower incidence of foot ulceration in Asian compared to European patients with type 2 diabetes.
Author URL.
Alam U, Fadavi H, Petropoulos I, Ponirakis G, Asghar O, Marshall A, Tavakoli M, Boulton AJM, Malik RA (2011). Protection from Neuropathy: Lessons from Patients with Long Duration Type 1 Diabetes.
Author URL.
Zhivov A, Stachs O (2011). Re: “Increased Langerhan cell density and corneal nerve damage in diabetic patients: Role of immune mechanisms in human diabetic neuropathy” by Tavakoli et al. Contact Lens and Anterior Eye, 34(2), 98-98.
Efron N, Tavakoli M, Boulton AJM, Malik R (2011). Reply to letter from Dr Zhivov and Dr Stachs. Contact Lens and Anterior Eye, 34(2), 99-99.
2010
Quattrini C, Tavakoli M, Kallinikos P, Marshall A, Efron N, Boulton AJM, Malik RA (2010). Comparing skin biopsy with corneal confocal microscopy: diagnostic yield of nerve fiber density.
Author URL.
Tavakoli M, Quattrini C, Abbott C, Kallinikos P, Marshall A, Finnigan J, Morgan P, Efron N, Boulton AJM, Malik RA, et al (2010). Corneal Confocal Microscopy.
Diabetes Care,
33(8), 1792-1797.
Abstract:
Corneal Confocal Microscopy
. OBJECTIVE
. The accurate quantification of human diabetic neuropathy is important to define at-risk patients, anticipate deterioration, and assess new therapies.
.
.
. RESEARCH DESIGN AND METHODS
. A total of 101 diabetic patients and 17 age-matched control subjects underwent neurological evaluation, neurophysiology tests, quantitative sensory testing, and evaluation of corneal sensation and corneal nerve morphology using corneal confocal microscopy (CCM).
.
.
. RESULTS
. Corneal sensation decreased significantly (P = 0.0001) with increasing neuropathic severity and correlated with the neuropathy disability score (NDS) (r = 0.441, P &lt; 0.0001). Corneal nerve fiber density (NFD) (P &lt; 0.0001), nerve fiber length (NFL), (P &lt; 0.0001), and nerve branch density (NBD) (P &lt; 0.0001) decreased significantly with increasing neuropathic severity and correlated with NDS (NFD r = −0.475, P &lt; 0.0001; NBD r = −0.511, P &lt; 0.0001; and NFL r = −0.581, P &lt; 0.0001). NBD and NFL demonstrated a significant and progressive reduction with worsening heat pain thresholds (P = 0.01). Receiver operating characteristic curve analysis for the diagnosis of neuropathy (NDS &gt;3) defined an NFD of &lt;27.8/mm2 with a sensitivity of 0.82 (95% CI 0.68–0.92) and specificity of 0.52 (0.40–0.64) and for detecting patients at risk of foot ulceration (NDS &gt;6) defined a NFD cutoff of &lt;20.8/mm2 with a sensitivity of 0.71 (0.42–0.92) and specificity of 0.64 (0.54–0.74).
.
.
. CONCLUSIONS
. CCM is a noninvasive clinical technique that may be used to detect early nerve damage and stratify diabetic patients with increasing neuropathic severity.
.
Abstract.
Petropoulos IN, Asghar O, Alam U, Fadavi H, Dabbah MA, Marshall A, Tavakoli M, Boulton AJM, Malik RA (2010). Corneal Confocal Microscopy Detects Neuropathy in Subjects with Impaired Glucose Tolerance.
Author URL.
Tavakoli M, Marshall A, Pitceathly R, Fadavi H, Gow D, Roberts ME, Efron N, Boulton AJM, Malik RA (2010). Corneal confocal microscopy: a novel means to detect nerve fibre damage in idiopathic small fibre neuropathy. Experimental Neurology, 223(1), 245-250.
Tavakoli M, Marshall A, Pitceathly R, Fadavi H, Gow D, Roberts ME, Efron N, Boulton AJM, Malik RA (2010). Corneal confocal microscopy: a novel means to detect nerve fibre damage in idiopathic small fibre neuropathy.
EXPERIMENTAL NEUROLOGY,
223(1), 245-250.
Author URL.
Petropoulos I, Fadavi H, Asghar O, Alam U, Ponirakis G, Tavakoli M, Malik R (2010). Diabetic neuropathy: Review of diagnosis and management.
Diabetes and Primary Care,
12(3), 165-174.
Abstract:
Diabetic neuropathy: Review of diagnosis and management
Diabetic neuropathy is common, under- or misdiagnosed, and causes not only substantial morbidity but also increased mortality. Apart from improving glycaemic control, there is no licensed treatment for diabetic neuropathy, although a number of pathogenetic pathways remain under active study. Focal and multifocal neuropathies are not common but can be extremely debilitating with few proven therapies. Autonomic dysfunction is more common, but significant deficits, although severe, are relatively rare, with limited therapeutic options. Painful diabetic neuropathy is a cause of considerable morbidity and many pharmacological as well as non-pharmacological interventions have been used. The recent NICE (2010) guidance provides an evidence-based rationale for the management of neuropathic pain in primary care. © John Wiley and Sons 2008.
Abstract.
Dabbah MA, Graham J, Petropoulos I, Tavakoli M, Malik RA (2010). Dual-model automatic detection of nerve-fibres in corneal confocal microscopy images.
Abstract:
Dual-model automatic detection of nerve-fibres in corneal confocal microscopy images
Abstract.
Dabbah MA, Graham J, Petropoulos I, Tavakoli M, Malik RA (2010). Dual-model automatic detection of nerve-fibres in corneal confocal microscopy images.
Med Image Comput Comput Assist Interv,
13(Pt 1), 300-307.
Abstract:
Dual-model automatic detection of nerve-fibres in corneal confocal microscopy images.
Corneal Confocal Microscopy (CCM) imaging is a non-invasive surrogate of detecting, quantifying and monitoring diabetic peripheral neuropathy. This paper presents an automated method for detecting nerve-fibres from CCM images using a dual-model detection algorithm and compares the performance to well-established texture and feature detection methods. The algorithm comprises two separate models, one for the background and another for the foreground (nerve-fibres), which work interactively. Our evaluation shows significant improvement (p approximately 0) in both error rate and signal-to-noise ratio of this model over the competitor methods. The automatic method is also evaluated in comparison with manual ground truth analysis in assessing diabetic neuropathy on the basis of nerve-fibre length, and shows a strong correlation (r = 0.92). Both analyses significantly separate diabetic patients from control subjects (p approximately 0).
Abstract.
Author URL.
Tavakoli M, Quattrini C, Begum P, Fadavi H, Boulton AJM, Malik RA (2010). Neuropad and corneal confocal microscopy: new indicators for human diabetic neuropathy.
Author URL.
Fadavi H, Tavakoli M, Petropoulos I, Chaturvedi N, Boulton AJM, Malik R, Abbott CA (2010). Predisposing Risk Factors Underlying the Reduced Risk of Foot Ulceration in South Asian Compared to European Patient with Diabetes.
Author URL.
Tavakoli M, Asghar O, Alam U, Petropoulos IN, Fadavi H, Malik RA (2010). Review: Novel insights on diagnosis, cause and treatment of diabetic neuropathy: focus on painful diabetic neuropathy.
Therapeutic Advances in Endocrinology and Metabolism,
1(2), 69-88.
Abstract:
Review: Novel insights on diagnosis, cause and treatment of diabetic neuropathy: focus on painful diabetic neuropathy
Diabetic neuropathy is common, under or misdiagnosed, and causes substantial morbidity with increased mortality. Defining and developing sensitive diagnostic tests for diabetic neuropathy is not only key to implementing earlier interventions but also to ensure that the most appropriate endpoints are employed in clinical intervention trials. This is critical as many potentially effective therapies may never progress to the clinic, not due to a lack of therapeutic effect, but because the endpoints were not sufficiently sensitive or robust to identify benefit. Apart from improving glycaemic control, there is no licensed treatment for diabetic neuropathy, however, a number of pathogenetic pathways remain under active study. Painful diabetic neuropathy is a cause of considerable morbidity and whilst many pharmacological and nonpharmacological interventions are currently used, only two are approved by the US Food and Drug Administration. We address the important issue of the ‘placebo effect’ and also consider potential new pharmacological therapies as well as nonpharmacological interventions in the treatment of painful diabetic neuropathy.
Abstract.
2009
Begum P, Tavakoli M, Malik RA, McLaughlin J (2009). AN "INSIGHT" INTO DIABETIC GASTROENTEROPATHY USING CORNEAL CONFOCAL MICROSCOPY.
Author URL.
Tavakoli M, Mojaddidi M, Fadavi H, Malik RA (2009). Chapter 2 Pathogenesis of human diabetic neuropathy. In (Ed) Diabetic Neuropathy, Oxford University Press.
Patel DV, Tavakoli M, Craig JP, Efron N, McGhee CNJ (2009). Corneal Sensitivity and Slit Scanning in Vivo Confocal Microscopy of the Subbasal Nerve Plexus of the Normal Central and Peripheral Human Cornea. Cornea, 28(7), 735-740.
Tavakoli M, Marshall A, Thompson L, Kenny M, Waldek S, Efron N, Malik RA (2009). Corneal confocal microscopy: a novel noninvasive means to diagnose neuropathy in patients with fabry disease. Muscle & Nerve, 40(6), 976-984.
Tavakoli M, Begum P, McLaughlin J, Malik RA (2009). Corneal confocal microscopy: a novel surrogate marker for diabetic autonomic neuropathy.
Author URL.
Tavakoli M (2009). Pathogenesis of Human Diabetic Neuropathy. In (Ed)
Diabetic Neuropathy, Oxford University Press, USA.
Abstract:
Pathogenesis of Human Diabetic Neuropathy
Abstract.
Fadavi H, Tavakoli M, Finnigan J, Doyle S, Chaturvedi N, Boulton AJM, Malik RA, Abbott CA (2009). Reduced Small Nerve Fibre Damage May Underlie a Lower Incidence of Foot Ulceration in Asian Compared to European Patients with Diabetes.
Author URL.
2008
Tavakoli M, Fadavi H, Malik RA (2008). Advances in the Diagnosis and Treatment of Painful Diabetic Neuropathy.
European Endocrinology,
4, 48-48.
Abstract:
Advances in the Diagnosis and Treatment of Painful Diabetic Neuropathy
Abstract.
Malik R (2008). Clinical applications of corneal confocal microscopy. Clinical Ophthalmology, 435-435.
Tavakoli M, Mehra S, Boulton AJ, Augustine T-T, Malik RA (2008). Corneal confocal microscopy detects early nerve regeneration in type 1 diabetic patients undergoing combined pancreas/kidney transplantation.
Author URL.
Pitceathly RDS, Tavakoli M, Marshall A, Roberts ME, Gow D, Efron N, Malik RA (2008). Corneal confocal microscopy to diagnose idiopathic small fibre neuropathy.
Author URL.
Tavakoli M, Marshall A, Roberts ME, Malik RA (2008). Corneal diabetic neuropathy: a new hallmark of peripheral diabetic neuropathy.
Author URL.
Mehra S, Tavakoli M, Tavakoli A, Parrott N, Malik R, Augustine T (2008). IMPROVEMENT IN DIABETIC NEUROPATHY AFTER SUCCESSFUL PANCREAS TRANSPLANTATION DETECTED BY CORNEAL CONFOCAL MICROSCOPY- TWO YEAR DATA. Transplantation, 86(2S).
Tavakoli M, Malik RA (2008). Management of painful diabetic neuropathy.
Expert Opin Pharmacother,
9(17), 2969-2978.
Abstract:
Management of painful diabetic neuropathy.
The commonest cause of peripheral neuropathy is diabetes and pain occurs in approximately 30% of diabetic patients with neuropathy. It is extremely distressing for the patient and poses significant difficulties in management, as no treatment to date provides total relief and the side effects of therapy limit dose titration. Understanding the pathogenesis of diabetic neuropathy may lead to the development of new treatments for preventing nerve damage. Furthermore, a better understanding of the mechanisms that modulate pain may lead to more effective relief of painful symptoms. This review provides an update on the assessment and treatment of painful diabetic neuropathy.
Abstract.
Author URL.
Tavakoli M, Mojaddidi M, Fadavi H, Malik RA (2008). Pathophysiology and treatment of painful diabetic neuropathy. Current Pain and Headache Reports, 12(3), 192-197.
Quattrini C, Jeziorska M, Tavakoli M, Begum P, Boulton AJM, Malik RA (2008). The Neuropad test: a visual indicator test for human diabetic neuropathy. Diabetologia, 51(6), 1046-1050.
2007
Mehra S, Tavakoli M, Kallinikos PA, Efron N, Boulton AJM, Augustine T, Malik RA (2007). Corneal Confocal Microscopy Detects Early Nerve Regeneration After Pancreas Transplantation in Patients with Type 1 Diabetes.
Diabetes Care,
30(10), 2608-2612.
Abstract:
Corneal Confocal Microscopy Detects Early Nerve Regeneration After Pancreas Transplantation in Patients with Type 1 Diabetes
OBJECTIVE—Corneal confocal microscopy (CCM) is a rapid, noninvasive, clinical examination technique that quantifies small nerve fiber pathology. We have used it to assess the neurological benefits of pancreas transplantation in type 1 diabetic patients.
. RESEARCH DESIGN AND METHODS—In 20 patients with type 1 diabetes undergoing simultaneous pancreas and kidney transplantation (SPK) and 15 control subjects, corneal sensitivity was evaluated using noncontact corneal esthesiometry, and small nerve fiber morphology was assessed using CCM.
. RESULTS—Corneal sensitivity (1.54 ± 0.28 vs. 0.77 ± 0.02, P &lt; 0.0001), nerve fiber density (NFD) (13.8 ± 2.1 vs. 42 ± 3.2, P &lt; 0.0001), nerve branch density (NBD) (4.04 ± 1.5 vs. 26.7 ± 2.5, P &lt; 0.0001), and nerve fiber length (NFL) (2.23 ± 0.2 vs. 9.69 ± 0.7, P &lt; 0.0001) were significantly reduced, and nerve fiber tortuosity (NFT) (15.7 ± 1.02 vs. 19.56 ± 1.34, P = 0.04) was increased in diabetic patients before pancreas transplantation. Six months after SPK, 15 patients underwent a second assessment and showed a significant improvement in NFD (18.04 ± 10.48 vs. 9.25 ± 1.87, P = 0.001) and NFL (3.60 ± 0.33 vs. 1.84 ± 0.33, P = 0.002) with no change in NBD (1.38 ± 0.74 vs. 1.38 ± 1.00, P = 1.0), NFT (15.58 ± 1.20 vs. 16.30 ± 1.19, P = 0.67), or corneal sensitivity (1.23 ± 0.39 vs. 1.54 ± 00.42, P = 0.59).
. CONCLUSIONS—Despite marked nerve fiber damage in type 1 diabetic patients undergoing pancreas transplantation, small fiber repair can be detected within 6 months of pancreas transplantation using CCM. CCM is a novel noninvasive clinical technique to assess the benefits of therapeutic intervention in human diabetic neuropathy.
Abstract.
Tavakoli M, Kallinikos PA, Efron N, Boulton AJM, Malik RA (2007). Corneal Sensitivity is Reduced and Relates to the Severity of Neuropathy in Patients with Diabetes. Diabetes Care, 30(7), 1895-1897.
Dash SK (2007). Corneal Sensitivity is Reduced and Relates to the Severity of Neuropathy in Patients with Diabetes. Diabetes Care, 30(12), e142-e142.
Tavakoli M, Abbott C, Quattrini C, Middlemas A, Karamoysoyli E, Tomlinson DR, Boulton AJM, Malik RA (2007). Corneal confocal microscopy and plasma p75NTR: new surrogate markers of human diabetic neuropathy.
Author URL.
Mehra S, Tavakoli M, Kallinikos P, Efron N, Boulton AJM, Augustine T, Malik RA (2007). Corneal confocal microscopy detects early nerve regeneration after pancreas transplantation in diabetic patients despite severe neuropathy.
Author URL.
Mehra S, Tavakoli M, Tavakoli A, Malik R, Parajasingam R, Parrott NR, Augustine TA (2007). Corneal confocal microscopy detects early neural regeneration in type 1 diabetics after pancreas transplantation.
Author URL.
Tavakoli M, Kallinikos PA, Efron N, Boulton AJM, Malik RA (2007). Corneal sensitivity is reduced and relates to the severity of neuropathy in patients with diabetes: Response to Dash [16]. Diabetes Care, 30(12).
Tavakoli M, Middlemas A, Kararrloysoli E, Abbott C, Quattrini C, Malik RA, Boulton AJM, Tomlinson DR (2007). Is p75NTR a new surrogate marker of diabetic neuropathy?.
Author URL.
Greenstein A, Tavakoli M, Mojaddidi M, Al-Sunni A, Matfin G, Malik RA (2007). Microvascular complications: Evaluation and monitoring relevance to clinical practice, clinical trials, and drug development.
British Journal of Diabetes and Vascular Disease,
7(4), 166-171.
Abstract:
Microvascular complications: Evaluation and monitoring relevance to clinical practice, clinical trials, and drug development
The long-term microvascular complications of diabetes pose a major health burden. Although, much of the focus has been on the macrovascular complications, it is clear that the microvascular complications have a significant impact on both morbidity and mortality amongst diabetic patients. Indeed retinopathy, nephropathy, and neuropathy compete as the leading causes of premature blindness, end-stage renal disease, and non-traumatic lower-limb amputation, respectively. Furthermore, complications develop and progress in unison and indeed share many common risk factors. Effective evaluation and monitoring of these complications in clinical practice is clearly important, however, it is also relevant to clinical intervention studies, and drug development programs addressing microvascular complications. Novel diagnostic and therapeutic strategies are continually evolving in this area and will be discussed in more detail in this review.
Abstract.
Quattrini C, Tavakoli M, Jeziorska M, Kallinikos P, Tesfaye S, Finnigan J, Marshall A, Boulton AJM, Efron N, Malik RA, et al (2007). Surrogate Markers of Small Fiber Damage in Human Diabetic Neuropathy.
Diabetes,
56(8), 2148-2154.
Abstract:
Surrogate Markers of Small Fiber Damage in Human Diabetic Neuropathy
Surrogate markers of diabetic neuropathy are being actively sought to facilitate the diagnosis, measure the progression, and assess the benefits of therapeutic intervention in patients with diabetic neuropathy. We have quantified small nerve fiber pathological changes using the technique of intraepidermal nerve fiber (IENF) assessment and the novel in vivo technique of corneal confocal microscopy (CCM). Fifty-four diabetic patients stratified for neuropathy, using neurological evaluation, neurophysiology, and quantitative sensory testing, and 15 control subjects were studied. They underwent a punch skin biopsy to quantify IENFs and CCM to quantify corneal nerve fibers. IENF density (IENFD), branch density, and branch length showed a progressive reduction with increasing severity of neuropathy, which was significant in patients with mild, moderate, and severe neuropathy. CCM also showed a progressive reduction in corneal nerve fiber density (CNFD) and branch density, but the latter was significantly reduced even in diabetic patients without neuropathy. Both IENFD and CNFD correlated significantly with cold detection and heat as pain thresholds. Intraepidermal and corneal nerve fiber lengths were reduced in patients with painful compared with painless diabetic neuropathy. Both IENF and CCM assessment accurately quantify small nerve fiber damage in diabetic patients. However, CCM quantifies small fiber damage rapidly and noninvasively and detects earlier stages of nerve damage compared with IENF pathology. This may make it an ideal technique to accurately diagnose and assess progression of human diabetic neuropathy.
Abstract.
2006
Tavakoli M, Mehra S, Augustine T, Malik RA (2006). Corneal confocal microscopy detects early nerve regeneration after pancreas transplantation.
Author URL.
Tavakoli M, Quattrini C, Abbott C, Kallinikos P, Tomlinson D, Efron N, Boulton AJM, Malik RA (2006). Corneal confocal microscopy is a non-invasive surrogate of nerve fibre damage and repair in diabetic patients.
Author URL.
Mehra S, Tavakoli M, Palmer A, Tavakoli A, Pararajasingam R, Parrott NR, Malik R, Augustine T (2006). EARLY NEURAL REGENERATION AFTER PANCREAS TRANSPLANTATION DETECTED BY CORNEAL CONFOCAL MICROSCOPY: a PILOT STUDY. Transplantation, 82(1).
2005
Quattrini C, Kallinikos P, Tavakoli M, Jeziorska M, Sheard A, Finnigan J, Boulton A, Efron N, Malik R (2005). Corneal confocal microscopy is superior to skin biopsy as a surrogate marker of human diabetic neuropathy.
Author URL.
Mojaddidi M, Quattrini C, Tavakoli M, Malik RA (2005). Recent developments in the assessment of efficacy in clinical trials of diabetic neuropathy. Current Diabetes Reports, 5(6), 417-422.
2001
Tavakoli M (2001). Yekta AA, Tavakoli M, Study of the prevalence of types and amounts of refractive errors in different ages among patients examined at the department of optometry, Mashad University of Medical Sciences, Iranian J. Basic Medical Sciences 2001; 4: 106-115. Iranian J. Basic Medical Sciences, 4, 106-115.
1959
Gellman DD, Pirani CL, Soothill JF, Muehrcke RC, Kark RM (1959). Diabetic nephropathy: a clinical and pathologic study based on renal biopsies. Medicine (United States), 38(4), 321-367.
