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<0.001), CNFL (p<0.001) and corneal nerve branch density (CNBD, p<0.001) compared to healthy subjects. In subjects who had no evidence of DR (67% of all subjects), 12.0% had abnormal CNFL. Conclusions: CCM may be a sensitive biomarker for early detection and screening of DPN in primary care alongside retinopathy screening.

Sodium Glucose Cotransporter-2 Inhibitor Protects Against Diabetic Neuropathy and Nephropathy in Modestly Controlled Type 2 Diabetes: Follow-Up Study.

Aims: This three-year follow-up study aimed to elucidate whether sodium-glucose cotransporter-2 inhibitors (SGLT2is) have any protection against diabetic neuropathy and nephropathy in patients with type 2 diabetes via reducing variability in glycemia and extraglycemic factors or their averages. Methods: Two type 2 diabetic cohorts of 40 and 73 patients treated with or without SGLT2i along with 60 control subjects were recruited. Two diabetic cohorts matched for HbA1c levels and oral hypoglycemic agents other than SGLT2is underwent glycemic control with or without SGLT2is more than two years. The urinary albumin to creatinine ratio (ACR), estimated glomerular filtration rate (eGFR) every 3 months and neuropathy outcome measures and mean Z-score of 8 neurophysiological tests were determined at the baseline and endpoint. Glycemic variability, evaluated by the coefficient of variation of monthly measured HbA1c levels and casual postprandial plasma glucose (CPPG), and coefficient of variation and average of extraglycemic parameters in diabetic cohorts were determined. Results: The glycemic variability and variability of some extraglycemic factors in SGLT2i cohort were smaller than those in non-SGLT2i cohort. However, only smaller coefficient of variation of HbA1c improved some neuropathy outcome measures, and ameliorated eGFR decline. SGLT2i improved the Z-score of neurophysiological tests. The optimized changes in the blood pressure, HDL-cholesterol and uric acid by SGLT2i led to neurological and renal protection. SGLT2i decreased the prevalence of nephropathy significantly and the prevalence of neuropathy insignificantly. Conclusion: Over 3 years period, SGLT2i significantly improved some neuropathy outcome measures, mean Z-score of 8 neurophysiological tests, and attenuated nephropathy in modestly controlled type 2 diabetes by reducing glycemic variability and mean nonglycemic factors of diabetic microvascular complication.

Advances in Screening, Early Diagnosis and Accurate Staging of Diabetic Neuropathy.

The incidence of both type 1 and type 2 diabetes is increasing worldwide. Diabetic peripheral neuropathy (DPN) is among the most distressing and costly of all the chronic complications of diabetes and is a cause of significant disability and poor quality of life. This incurs a significant burden on health care costs and society, especially as these young people enter their peak working and earning capacity at the time when diabetes-related complications most often first occur. DPN is often asymptomatic during the early stages; however, once symptoms and overt deficits have developed, it cannot be reversed. Therefore, early diagnosis and timely intervention are essential to prevent the development and progression of diabetic neuropathy. The diagnosis of DPN, the determination of the global prevalence, and incidence rates of DPN remain challenging. The opinions vary about the effectiveness of the expansion of screenings to enable early diagnosis and treatment initiation before disease onset and progression. Although research has evolved over the years, DPN still represents an enormous burden for clinicians and health systems worldwide due to its difficult diagnosis, high costs related to treatment, and the multidisciplinary approach required for effective management. Therefore, there is an unmet need for reliable surrogate biomarkers to monitor the onset and progression of early neuropathic changes in DPN and facilitate drug discovery. In this review paper, the aim was to assess the currently available tests for DPN's sensitivity and performance.

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.

Aims: To 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. Methods: Thirty-one poorly controlled (HbA1c > 8.0%) patients with type 2 diabetes without diabetic retinopathy undergoing glycemic control and 39 control subjects with normal HbA1c levels (< 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. Results: Glycemic 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. Conclusion: Glycemic 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.

Thinning of Macular Neuroretinal Layers Contributes to Sleep Disorder in Patients With Type 2 Diabetes Without Clinical Evidences of Neuropathy and Retinopathy.

Aims: To investigate the impact of thinning at individual grids of macular neuroretinal layers, clinical factors, and inadequate light exposure on the specific components of sleep disorder in patients with type 2 diabetes. Methods: One hundred twenty-four patients with type 2 diabetes without clinical evidences of diabetic retinopathy and neuropathy (HbA1c: 8.3%, diabetes duration; 8.7 years) and 54 age- and sex-matched control subjects (HbA1c: 5.6%) underwent detailed clinical, neurological, and ophthalmological examinations. The sleep disorder was assessed by the Pittsburgh Sleep Quality Index Japanese Version (PSQI-J). The temporal structures of daily life were assessed by the Munich Chronotype Questionnaire Japanese Version. The thickness at nine grids defined by the Early Treatment Diabetic Retinopathy Study of nine macular neuroretinal layers was determined by swept-source optical coherence tomography and OCT-Explorer. The associations between the individual components of sleep disorders and the thickness at each grid of macular neuroretinal layers, clinical factors, or the temporal structures of daily life were examined. Results: The prevalence of the sleep disorder, global score, and four individual PSQI-J scores in patients with type 2 diabetes were higher than control subjects. The thickness of two and five grids of two inner retinal layers and four to seven grids of four outer retinal layers in patients with type 2 diabetes was thinner than those in control subjects. The thickness at one to eight grids of four outer retinal layers in type 2 diabetic patients was inversely associated with global score and five individual scores of sleep disorder. The thinning at one to two grids of the inner plexiform layer was related to three high individual scores of sleep disorder. The inappropriate light exposure was associated with the sleep disorder and altered macular neuroretinal layers. The high HbA1c and LDL-cholesterol levels were related to the high global score and two individual scores of sleep disorder, respectively. Conclusion: In patients with type 2 diabetes, the thinning at grids of the inner plexiform layer and outer retinal layers was associated with the high scores of specific components of the sleep disorder. The sleep disorder was also related to hyperglycemia, dyslipidemia, and inappropriate light exposure.

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.

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.

The Preferential Impairment of Pupil Constriction Stimulated by Blue Light in Patients with Type 2 Diabetes without Autonomic Neuropathy.

The main aim of the present paper is to examine whether the pupillary light reflex (PLR) mediated by intrinsically photosensitive retinal ganglion cells (ipRGCs) is impaired in type 2 diabetic patients. One hundred and three diabetic patients without diabetic autonomic neuropathy (DAN) and 42 age-matched controls underwent a series of detailed neurological examinations. The patients were stratified into three groups: stage I, no neuropathy; stage II, asymptomatic neuropathy; stage III, symptomatic but without DAN. The PLR to 470 and 635 nm light at 20 cd/m2 was recorded. Small fiber neuropathy was assessed by corneal confocal microscopy and quantifying corneal nerve fiber (CNF) morphology. The 470 nm light induced a stronger and faster PLR than did 635 nm light in all subjects. The PLR to both lights was impaired equally across all of the diabetic subgroups. The postillumination pupil response (PIPR) after 470 nm light offset at ≥1.7 sec was attenuated in diabetic patients without differences between subgroups. Receiver operating characteristic analysis revealed that the PIPR mediated by ipRGCs in patients with stage II and stage III neuropathy was different from that of the control subjects. Clinical factors, nerve conduction velocity, and CNF measures were significantly correlated with PLR parameters with 470 nm light. PLR kinetics were more impaired by stimulation with blue light than with red light in diabetic patients without DAN.

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.

Elasticity of the tibial nerve assessed by sonoelastography was reduced before the development of neuropathy and further deterioration associated with the severity of neuropathy in patients with type 2 diabetes.

AIMS/INTRODUCTION: To measure the elasticity of the tibial nerve using sonoelastography, and to associate it with diabetic neuropathy severity, the cross-sectional area of the tibial nerve and neurophysiological findings in type 2 diabetic patients. MATERIALS AND METHODS: The elasticity of the tibial nerve was measured as the tibial nerve:acoustic coupler strain ratio using high-resolution ultrasonography in 198 type 2 diabetic patients stratified into subgroups by neuropathy severity, and 29 control participants whose age and sex did not differ from the diabetic subgroups. RESULTS: The elasticity of the tibial nerve in patients without neuropathy (P < 0.001) was reduced compared with controls (0.76 ± 0.023), further decreasing (0.655 ± 0.014 to 0.414 ± 0.018) after developing neuropathy. The cut-off value of elasticity of the tibial nerve that suggested the presence of neuropathy was 0.558. The area under the curve (0.829) was greater than that for the cross-sectional area (0.612). The cross-sectional area of the tibial nerve in diabetic patients without neuropathy (6.11 ± 0.13 mm(2)) was larger than that in controls (4.84 ± 0.16 mm(2)), and increased relative to neuropathy severity (P < 0.0001). The elasticity of the tibial nerve was negatively associated with neuropathy severity (P < 0.0001), cross-sectional area (P = 0.002) and 2000 Hz current perception threshold (P = 0.011), and positively associated with nerve conduction velocities (P < 0.0001). CONCLUSIONS: Determining the elasticity of the tibial nerve in type 2 diabetic patients could reveal early biomechanical changes that were likely caused by thickened fibrous sheaths of peripheral nerves, and might be a novel tool for characterizing diabetic neuropathy.

Morphological changes of the peripheral nerves evaluated by high-resolution ultrasonography are associated with the severity of diabetic neuropathy, but not corneal nerve fiber pathology in patients with type 2 diabetes.

AIMS/INTRODUCTION: To evaluate the morphological changes of the median and posterior tibial nerve using high-resolution ultrasonography, and the corneal C fiber pathology by corneal confocal microscopy in type 2 diabetic patients. MATERIALS AND METHODS: The cross-sectional area, hypoechoic area and maximum thickness of the nerve fascicle of both nerves were measured by high-resolution ultrasonography in 200 type 2 diabetic patients, stratified by the severity of diabetic neuropathy, and in 40 age- and sex-matched controls. These parameters were associated with corneal C fiber pathology visualized by corneal confocal microscopy, neurophysiological tests and severity of diabetic neuropathy. RESULTS: The cross-sectional area, hypoechoic area and maximum thickness of the nerve fascicle of both nerves in patients without diabetic neuropathy were larger than those in control subjects (P < 0.05 to P < 0.001), and further increased relative to the severity of neuropathy (P < 0.0001). All morphological changes of both nerves were negatively associated with motor and sensory nerve conduction velocity (P = 0.01 to P < 0.0001), and directly associated with 2,000-Hz current perception threshold (P = 0.009 to P < 0.001). The significant corneal C fiber pathology occurred before developing the neuropathy, and deteriorated only in patients with the most severe neuropathy. The association between the morphological changes of both nerves and corneal C fiber pathology was poor. CONCLUSIONS: The morphological changes in peripheral nerves of type 2 diabetic patients were found before the onset of neuropathy, and were closely correlated with the severity of diabetic neuropathy, but not with corneal C fiber pathology.

Correlation between sudomotor function, sweat gland duct size and corneal nerve fiber pathology in patients with type 2 diabetes mellitus.

AIMS/INTRODUCTION: To study the correlation between sudomotor function, sweat gland duct size and corneal nerve fiber pathology in type 2 diabetes. MATERIALS AND METHODS: Sudomotor function was quantified by Neuropad test, and sweat gland duct and corneal nerve fibers were visualized by confocal microscopy in 78 patients with type 2 diabetes stratified by diabetic neuropathy and 28 control participants. RESULTS: In patients with diabetic neuropathy, sudomotor function, as judged by the time required for complete color change of a Neuropad, was impaired compared with that of controls (P < 0.0001), thereby showing deterioration was related to the severity of diabetic neuropathy (P < 0.0001). Sweat gland ducts were smaller in patients without neuropathy than in controls (P < 0.0001), and further shrinking was seen in patients with severe diabetic neuropathy (P < 0.05). Patients without diabetic neuropathy showed reduced density and length (P < 0.001) of corneal nerve fibers and beading frequency (P < 0.0001), and increased tortuosity (P < 0.0001) compared with controls, and these changes deteriorated in patients with severe diabetic neuropathy. Sudomotor function was negatively associated with corneal nerve fibers (P < 0.002) and branches (P < 0.01), and influenced by the severity of diabetic neuropathy (P < 0.0001); sweat gland duct size correlated with serum triglycerides (P < 0.02), uric acid (P < 0.01), corneal nerve branch (P < 0.03), sudomotor function (P < 0.03) and severity of neuropathy (P < 0.03). CONCLUSIONS: Type 2 diabetic patients had sudomotor dysfunction and smaller sweat gland ducts compared with controls. The stage of diabetic neuropathy and corneal nerve fiber pathology were independent predictors of sudomotor dysfunction, and serum triglycerides, uric acid, corneal nerve branch, stage of diabetic neuropathy and sudomotor function were predictors of sweat gland duct size.

Accumulation of oxidative stress-related gene polymorphisms and the risk of coronary heart disease events in patients with type 2 diabetes--an 8-year prospective study.

OBJECTIVE: Oxidative stress, which is provoked in patients with diabetes, plays critical roles in the pathogenesis of coronary heart disease (CHD). We simultaneously determined 5 relatively common genetic variants related to oxidative stress and evaluated the combined effect on CHD. METHODS: We enrolled 1977 Japanese type 2 diabetic subjects without history of CVD (males 66.1%, 59.5 ± 10.0 years old), determined their genotypes regarding glutamate-cysteine ligase modifier subunit (GCLM) C-588T, manganese superoxide dismutase (SOD2) Val16Ala, endothelial nitric oxide synthase (NOS3) G894T, NAD(P)H oxidase p22phox (CYBA) C242T, and myeloperoxidase (MPO) G-463A polymorphisms, and prospectively evaluated the association between these polymorphisms and CHD events. RESULTS: The median follow-up period was 7.5 years and there were 85 new CHD events. The single association analysis revealed that there were no statistically significant associations between each polymorphism and the prevalence of CHD. Interestingly, the risk of CHD event was higher with the increase of the total number of 10 concomitant unfavorable "pro-oxidant alleles" in each subject (p for trend = 0.018, log-rank test). Especially, the carriers of ≥8 pro-oxidant alleles had a significantly increased risk as compared to the carriers of <8 pro-oxidant alleles, whether the other clinical variables were adjusted (HR 2.92 with 95%CI 1.50-5.67, p = 0.002) or not (HR 2.89 with 95%CI 1.49-5.59, p = 0.002).. CONCLUSIONS: Accumulation of gene polymorphisms related to oxidative stress is likely associated with the development of CHD in patients with type 2 diabetes, suggesting that the combined information about these variants is useful to assess the risk of CHD.

Morphometric features of corneal epithelial basal cells, and their relationship with corneal nerve pathology and clinical factors in patients with type 2 diabetes.

AIMS/INTRODUCTION: We compared the morphometric features of corneal epithelial basal cells between patients with type 2 diabetes mellitus and healthy controls, and analyzed the relationship of these features with corneal nerve fiber pathology and clinical factors in the patients. MATERIALS AND METHODS: Corneal epithelial basal cells and corneal nerve fibers were visualized by corneal confocal microscopy in 75 patients with type 2 diabetes and 42 age-matched controls. Density, area and area variability of corneal epithelial basal cells, as well as the width of the intercellular space between neighboring cells, were evaluated for both groups. RESULTS: Patients showed decreased density (P < 0.02) and area (P < 0.0001), larger area variability (P < 0.0001) and a wider intercellular space (P < 0.0001) compared with controls. Density correlated inversely with area (P < 0.0001), width of intercellular space (P < 0.03) and beading frequency (P < 0.03), whereas it correlated directly with prothrombin time (P < 0.002) and activated partial thromboplastin time (P < 0.03). Area correlated inversely with duration of diabetes (P < 0.05) and coefficient of variation of area (P < 0.01), whereas it correlated directly with beading frequency (P < 0.05). Area variability correlated inversely with area (P < 0.01) and prothrombin time (P < 0.01), whereas it correlated directly with fibrinogen level (P < 0.0001). CONCLUSIONS: Type 2 diabetes induces morphometric changes in corneal epithelial basal cells; this seems to be related to the morbid period of diabetes, beading frequency of corneal nerve fibers and blood coagulation state.

Corneal nerve fiber pathology in Japanese type 1 diabetic patients and its correlation with antecedent glycemic control and blood pressure.

UNLABELLED: Aims/Introduction: Morphological changes to corneal C-fibers in Japanese type 1 diabetic patients were visualized by corneal confocal microscopy (CCM). The effects of prior glycemic control and blood pressure on morphological parameters were clarified. MATERIALS AND METHODS: Corneal nerve fibers were visualized by CCM in 38 Japanese type 1 diabetic patients (14 with and 24 without neuropathy) and 38 controls. Morphological parameters were compared and related to annual mean HbA1c, blood pressure, and serum lipid levels of previous years prior to CCM examination. RESULTS: Compared with controls, diabetic patients had reduced corneal nerve fiber length (CNFL; 9.80 ± 0.38 vs 13.65 ± 0.88 mm/mm(2); P < 0.001), reduced density (CNFD; 25.32 ± 1.04 vs 36.62 ± 2.37/mm(2); P < 0.0005), lower frequency of beading (22.38 ± 0.73 vs 30.44 ± 1.03/0.1 mm; P < 0.0001), and increased tortuosity (3.13 ± 0.09 vs 1.74 ± 0.06; P < 0.0001). These changes were found in patients without neuropathy. There was no difference in nerve branches between controls and diabetic patients. The mean annual HbA1c level for the 7-10 years prior to CCM examination was an independent predictor of reduced CNFL and CNFD; HbA1c levels obtained 1-3 months and 1 year prior to CCM, as well as blood pressure 3, 5, and 6 years prior to CCM, were independent predictors of reduced beading frequency. CONCLUSIONS: Corneal confocal microscopy is a novel, noninvasive technique to evaluate morphological changes of corneal C-fibers in type 1 diabetes. Antecedent hyperglycemia and blood pressure have different time-dependent effects on CNFL and CNFD and the frequency of beading. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2011.00157.x, 2011).

Adiponectin G276T gene polymorphism is associated with cardiovascular disease in Japanese patients with type 2 diabetes.

OBJECTIVE: Adiponectin has anti-atherogenic properties and reduced serum adiponectin levels are associated with cardiovascular disease (CVD). In this study, we examined the relationship between CVD and adiponectin (ADIPOQ) gene G276T polymorphism that is associated with serum adiponectin level in a large cohort of type 2 diabetic patients. RESEARCH DESIGN AND METHODS: We enrolled 2637 Japanese type 2 diabetic subjects (males, 61.1%; age, 54.9±7.9 years old), determined their genotypes regarding ADIPOQ G276T polymorphisms, and evaluated the association between this polymorphism and the prevalence of CVD (myocardial infarction and/or cerebral infarction). RESULTS: The prevalence of CVD tended to be higher as the number of G alleles increased [GG (9.5%), GT (6.8%), TT (5.6%), p value for trend=0.0059] and was significantly higher in the subjects with GG genotype compared to those with GT or TT genotype (9.5% vs. 6.6%, p=0.0060). Multiple logistic regression analyses revealed that the number of G alleles (Odds ratio (OR)=1.49 with 95%CI 1.09-2.05, p=0.0125) and GG genotype (OR=1.66 with 95%CI 1.13-2.43, p=0.0098) were significantly associated with CVD even after adjustment for conventional risk factors. Interestingly, the presence of obesity further and significantly increased the risk of CVD in the subjects with GG genotype (OR=1.67 with 95%CI 1.14-2.44, p=0.0090) but not in the subjects with TT or GT genotype (OR=1.17 with 95%CI 0.73-1.89, NS). CONCLUSIONS: It is likely that the G allele of the ADIPOQ G276T polymorphism is a susceptibility allele for CVD in Japanese type 2 diabetic patients, especially when they accompany obesity.

Accumulation of gene polymorphisms related to oxidative stress is associated with myocardial infarction in Japanese type 2 diabetic patients.

OBJECTIVE: It is believed that oxidative stress, which is provoked in patients with diabetes, plays critical roles in the pathogenesis of myocardial infarction (MI). We simultaneously determined 5 relatively common genetic variants related to oxidative stress and evaluated the combined effect on MI. METHODS: We enrolled 3819 Japanese type 2 diabetic subjects (males 60.8%, 60.6±10.0 years old) and determined their genotypes regarding glutamate-cysteine ligase modifier subunit (GCLM) C-588T, manganese superoxide dismutase (SOD2) Val16Ala, endothelial nitric oxide synthase (NOS3) G894T, NAD(P)H oxidase p22phox (CYBA) C242T, and myeloperoxidase (MPO) G-463A polymorphisms. The diagnosis of the occurrence of MI was based on the clinical records, characteristic ECG changes, and the findings in coronary angiography and echocardiography. RESULTS: The single association analysis revealed that there were no statistically significant associations between each polymorphism and the prevalence of MI. Interestingly, the prevalence of MI was higher with the increase of the total number of 5 concomitant unfavorable "pro-oxidant alleles" in each subject (p value for linear trend=0.018). Furthermore, a multiple logistic regression analysis showed that the number of pro-oxidant alleles was a risk factor for MI independently of conventional risk factors (odds ratio for 1-point increase in the number of pro-oxidant allele=1.16 with 95% CI 1.01-1.34, p=0.034). CONCLUSIONS: Accumulation of gene polymorphisms related to oxidative stress is likely associated with the prevalence of MI in type 2 diabetic patients, suggesting that the combined information about these variants is useful to assess the risk of MI.

Monocyte chemoattractant protein-1 (MCP-1) gene polymorphism as a potential risk factor for diabetic retinopathy in Japanese patients with type 2 diabetes.

We examined the association between diabetic retinopathy and monocyte chemoattractant protein (MCP)-1 A-2518G polymorphism in 3802 Japanese type 2 diabetic subjects. The prevalence of diabetic retinopathy was higher as the number of G alleles increased, suggesting that the G allele of this polymorphism is a susceptibility allele for diabetic retinopathy.

Accumulation of gene polymorphisms related to plaque disruption and thrombosis is associated with cerebral infarction in subjects with type 2 diabetes.

OBJECTIVE: It is believed that disruption of vulnerable atherosclerotic plaque and subsequent thrombus formation play critical roles in the pathogenesis of cerebral infarction. We simultaneously determined four relatively common genetic variants related to plaque rupture or subsequent local thrombus formation and evaluated the combined effect on cerebral infarction. RESEARCH DESIGN AND METHODS: We enrolled 3,094 Japanese type 2 diabetic subjects (62.7% male; aged 61.5 +/- 8.4 years) and determined their genotypes regarding matrix metalloproteinase 9 C-1562T, coagulation factor XII (F12) C46T, von Willebrand factor (VWF) G-1051A, and plasminogen activator inhibitor (PAI-1) 675 4G/5G polymorphisms. The diagnosis of cerebral infarction was performed based on history, physical examination, and neuroimaging. RESULTS: The single association analysis revealed that there were no statistically significant associations between each polymorphism and the prevalence of cerebral infarction. Interestingly, the prevalence of cerebral infarction was higher with the increase of the total number of four concomitant unfavorable proatherothrombotic alleles in each subject (P value for linear trend = 0.004). Furthermore, a multiple logistic regression analysis showed that the number of proatherothrombotic alleles was a risk factor for cerebral infarction independently of conventional risk factors (odds ratio for one-point increase in the number of proatherothrombotic allele 1.15 [95% CI 1.05-1.26], P = 0.004). CONCLUSIONS: Accumulation of gene polymorphisms related to plaque rupture and thrombus formation is likely associated with the prevalence of cerebral infarction in type 2 diabetic patients, suggesting that the combined information about these variants is useful to assess the risk of cerebral infarction.