Benefits of early glycemic control by insulin on sensory neuropathy and cataract in diabetic rats.

While there is an emphasis on the early glycemic control for its long-term benefits in preventing microvascular complications of diabetes, the biochemical mechanisms responsible for the long-lasting effects are not clearly understood. Therefore the impact of early insulin (EI) versus late insulin (LI) treatment on diabetic sensory neuropathy and cataract in streptozotocin-induced diabetic Wistar male rats were evaluated. EI group received insulin (2.5 IU/animal, once daily) treatment from day 1 to 90 while LI group received insulin from day 60 to 90. Early insulin treatment significantly reduced the biochemical markers like glucose, triglyceride, glycated hemoglobin, thiobarbituric acid reactive substances, advanced glycation end products and ratio of reduced glutathione and oxidized glutathione in diabetic rats. The late insulin treatment failed to resist the biochemical changes in diabetic rats. Diabetic rats developed sensory neuropathy as evidenced by mechanical and thermal hyperalgesia and showed a higher incidence and severity of cataract as revealed by slit lamp examination. Early insulin treatment protected the rats from the development of neuropathy and cataract, but late insulin administration failed to do so. The results demonstrate the benefits of early glycemic control in preventing neuropathy and cataract development in diabetic rats.

Imbalanced levels of angiogenic and angiostatic factors in vitreous, plasma and postmortem retinal tissue of patients with proliferative diabetic retinopathy.

A role for vascular endothelial growth factor (VEGF) has been clearly implicated in the pathogenesis of proliferative diabetic retinopathy (PDR). However, other molecules and mechanisms may be operating independently, or in conjunction with VEGF in the pathogenesis of this disease. Therefore, we made an attempt to comparatively investigate the levels of angiogenic and angiostatic factors in vitreous, plasma and postmortem retinal tissue of subjects with Proliferative Diabetic Retinopathy (PDR) compared to control subjects. The vitreous and plasma concentrations of VEGF, EPO (Erythropoietin) and PEDF (Pigment Epithelium Derived Factor) were measured using Enzyme Linked Immunosorbent Assay (ELISA) and the postmortem retinal tissue was subjected to Western blot analysis. The mean vitreous and plasma levels of VEGF and EPO in patients with PDR were significantly (p<0.001) higher than those in subjects without diabetes. Conversely, the vitreous and plasma levels of PEDF were significantly (p<0.001) lower in the PDR patients compared to control subjects. Multivariate logistic-regression analyses indicated that EPO was more strongly associated with PDR than VEGF. The protein expression of the VEGF and EPO in the retinal tissue was significantly higher in PDR and diabetes without complication groups compared to controls. Compared to controls, the protein expression of PEDF was significantly lower in retinal tissues from diabetes patients without complications and in patients with PDR. The fact that the vitreous and plasma levels and the retinal tissue protein expression of EPO were strongly associated with PDR implies a definite role of 'hypererythropoietinemia' in neovascularization processes.

Global prevalence and major risk factors of diabetic retinopathy.

OBJECTIVE: To examine the global prevalence and major risk factors for diabetic retinopathy (DR) and vision-threatening diabetic retinopathy (VTDR) among people with diabetes. RESEARCH DESIGN AND METHODS: A pooled analysis using individual participant data from population-based studies around the world was performed. A systematic literature review was conducted to identify all population-based studies in general populations or individuals with diabetes who had ascertained DR from retinal photographs. Studies provided data for DR end points, including any DR, proliferative DR, diabetic macular edema, and VTDR, and also major systemic risk factors. Pooled prevalence estimates were directly age-standardized to the 2010 World Diabetes Population aged 20-79 years. RESULTS: A total of 35 studies (1980-2008) provided data from 22,896 individuals with diabetes. The overall prevalence was 34.6% (95% CI 34.5-34.8) for any DR, 6.96% (6.87-7.04) for proliferative DR, 6.81% (6.74-6.89) for diabetic macular edema, and 10.2% (10.1-10.3) for VTDR. All DR prevalence end points increased with diabetes duration, hemoglobin A(1c), and blood pressure levels and were higher in people with type 1 compared with type 2 diabetes. CONCLUSIONS: There are approximately 93 million people with DR, 17 million with proliferative DR, 21 million with diabetic macular edema, and 28 million with VTDR worldwide. Longer diabetes duration and poorer glycemic and blood pressure control are strongly associated with DR. These data highlight the substantial worldwide public health burden of DR and the importance of modifiable risk factors in its occurrence. This study is limited by data pooled from studies at different time points, with different methodologies and population characteristics.

Clinical profile of diabetes in the young seen between 1992 and 2009 at a specialist diabetes centre in south India.

AIM: To describe the trends and clinical profile of young diabetic patients (YD) attending a tertiary diabetes centre in south India. METHODS: We reviewed medical records of 2630 YD patients (age at onset ≤25 years) registered between 1992 and 2009. Patients were classified as type 1 diabetes (T1DM), type 2 diabetes (T2DM) gestational diabetes mellitus (GDM) and other types. Retinopathy was assessed initially by direct and indirect ophthalmoscopy and later by retinal photography, nephropathy if urine protein excretion was >500 mg/day, neuropathy if vibration perception threshold on biothesiometry was ≥20 V. RESULTS: The percentage of YD patients rose from 0.55% in 1992 to 2.5% in 2009 (trend chi square, 15.1, p<0.001). Of the 2630 YD subjects registered, 1135 (43.2%) had T1DM, 1262 (48.0%) had T2DM, 118 (4.5%) had GDM and 115 (4.4%) other types. T1DM patients were younger, had lower body mass index, waist circumference, systolic and diastolic blood pressures, and less family history of diabetes compared to T2DM (p<0.001 for each). Retinopathy was seen in 71.9% and 77.3% nephropathy in 22.1% and 12.1% and neuropathy in 34.5% and 21.4% of T2DM and T1DM respectively in those with ≥15 years duration of diabetes. CONCLUSIONS: The percentage of YD in south India is increasing, predominantly due to early onset T2DM.

Teleophthalmology: a model for eye care delivery in rural and underserved areas of India.

Objectives. To describe the application of teleophthalmology in rural and underserved areas of India. Study Design. This paper describes the major teleophthalmology projects in India and its benefits. Results. Teleophthalmology is the use of telecommunication for electronic transfer of health-related data from rural and underserved areas of India to specialities in urban cities. The MDRF/WDF Rural Diabetes Project has proved to be very beneficial for improvement of quality health care in Tamilnadu and can be replicated at the national level. This community outreach programme using telemedicine facilities has increased awareness of eye diseases, improved access to specialized health care, helped in local community empowerment, and provided employment opportunities. Early detection of sight threatening disorders by teleophthalmology and prompt treatment can help decrease visual impairment. Conclusion. Teleophthalmology can be a very effective model for improving eye care delivery system in rural and underserved areas of India.

Association of depression with complications of type 2 diabetes--the Chennai Urban Rural Epidemiology Study (CURES- 102).

OBJECTIVE: The aim of the study was to assess the relationship between depression and diabetic complications among urban south Indian type 2 diabetic subjects [T2DM]. METHODS: T2DM subjects [n = 847] were recruited from the Chennai Urban Rural Epidemiology Study [CURES], a population based study in Chennai (formerly Madras) in South India. A previously validated depression questionnaire [PHQ-12 item] was administered. Four field stereo retinal colour photography was done and diabetic retinopathy [DR] was classified according to the Early Treatment Diabetic Retinopathy Study grading system. Neuropathy was diagnosed if the vibratory perception threshold of the right great toe, measured by biothesiometry, was > or = 20. Nephropathy was diagnosed if urinary albumin excretion was > or = 300 microg/mg creatinine. Peripheral vascular disease [PVD] was diagnosed if an ankle-brachial index was < 0.9. Coronary artery disease [CAD] was diagnosed based on a past history of documented myocardial infarction and/or electrocardiographic evidence of Q wave and/or ST segment changes. RESULTS: Of the 847 T2DM studied, 198 (23.4%) were found have depression. The prevalence of depression was significantly higher among diabetic subjects with DR (35.0% vs 21.1%, p < 0.001), neuropathy (28.4% vs 15.9%, p = 0.023), nephropathy (35.6% vs 24.5%, p = 0.04) and PVD (48.0% vs 27.4%, p < 0.001) as compared to subjects without these complications. DR, neuropathy, nephropathy, and PVD were associated with depression even after adjusting for age, gender, duration of diabetes and glycated haemoglobin. DR (Odds ratio [OR] = 2.19, Confidence interval [CI]:1.45-3.51, p < 0.001) was associated with depression even after adjusting for neuropathy and nephropathy. There was also a significant association between depression and neuropathy, after adjusting for retinopathy and nephropathy (OR = 2.07, CI: 1.41-3.04, p < 0.001). There was a significant association of depression with nephropathy but this was lost (OR = 1.71, CI: 0.87-3.35, p = 0.119) after adjustment for retinopathy. PVD (OR = 3.52, CI: 1.94-6.40, p < 0.001) remained significantly associated with depression even after adjusting for CAD. However, there was no significant association of depression with CAD (OR = 0.73, CI: 0.42 -1.27, p = 0.264). CONCLUSION: Among Asian Indians, the prevalence of depression is higher in T2DM subjects with retinopathy, neuropathy, nephropathy and PVD compared to those without the respective complications.

Risk factors for microvascular complications of diabetes among South Indian subjects with type 2 diabetes--the Chennai Urban Rural Epidemiology Study (CURES) Eye Study-5.

BACKGROUND: This study assessed the relationship between and risk factors for microvascular complications of diabetes in an urban South Indian type 2 diabetes population. METHODS: Subjects with diabetes (n = 1,736) were selected from the population-based Chennai Urban Rural Epidemiology Study (CURES) Eye Study conducted on a representative population of Chennai city in south India. Four-field stereo retinal color photography was done, and diabetic retinopathy (DR) was classified according to the Early Treatment DR Study grading system. Neuropathy was diagnosed if the vibratory perception threshold of the big toe using biothesiometry was ≥ 20V. Overt nephropathy was diagnosed if the subjects had persistent macroalbuminuria (urinary albumin excretion ≥ 300 µg/mg of creatinine) and microalbuminuria if it was between 30 and 299 µg/mg of creatinine. Among the 1,715 subjects with gradable fundus photographs, 1,608 individuals who had information on all test parameters were included. RESULTS: Overall, DR was present in 282 (17.5%), neuropathy in 414 (25.7%), overt nephropathy in 82 (5.1%), and microalbuminuria in 426 (26.5%) subjects. Eighteen subjects had all three microvascular complications of diabetes. The risk of nephropathy (odds ratio [OR] = 5.3, P<0.0001) and neuropathy (OR = 2.9, P<0.0001) was significantly higher among the subjects with sight-threatening DR compared to those without DR. Common risk factors identified for all the three microvascular complications of diabetes were age, glycated hemoglobin, duration of diabetes, and serum triglycerides. DR was associated with nephropathy after adjusting for age, gender, hemoglobin A1c, systolic blood pressure, serum triglycerides, and duration of diabetes (OR = 2.140, 95% confidence interval = 1.261-3.632, P = 0.005). CONCLUSIONS: This is the first population-based study from India to report on all microvascular complications of diabetes and reveals that the association between DR and nephropathy is stronger than that with neuropathy.

Curcumin modulates SDF-1alpha/CXCR4-induced migration of human retinal endothelial cells (HRECs).

PURPOSE: The stromal-derived factor (SDF)-1alpha and the CXC receptor (CXCR)-4 jointly regulate the trafficking of various cell types and play a pivotal role in cell migration, proliferation, and survival. The purpose of this study was to assess whether curcumin inhibits human retinal endothelial cell (HREC) migration by interfering with SDF-1alpha/CXCR4 signaling. METHODS: Primary HREC culture was established and maintained in endothelial growth medium. The viability and proliferation of HRECs were assessed by MTT and thymidine uptake assays, respectively. The effect of SDF-1alpha-induced HREC migration (chemotaxis) in the presence and absence of curcumin was determined using the Boyden chamber migration assay. Intracellular Ca(2+) concentration was measured by fluorometric analysis. Immunofluorescence and Western blot analyses were performed to quantify CXCR4, phosphorylated AKT, and PI3-kinase expression levels. RESULTS: HREC migration increased in a dose-dependent manner (1, 10, 50, and 100 ng/mL; P < 0.001) in SDF-1alpha-treated cells. In contrast, AMD3100, an inhibitor of CXCR4 effectively inhibited HREC migration dose dependently. HREC migration was decreased when the cells were exposed to EGTA, a chelator of Ca(2+). Curcumin also blocked Ca(2+) influx, an important signal for HREC migration. In addition, curcumin significantly (P < 0.001) decreased SDF-1alpha-induced HRECs migration and downregulated SDF-1alpha-induced expression of CXCR4, phospho-AKT, phospho-phosphatidylinositol-3-kinase (PI3-K), and eNOS. CONCLUSIONS: This study indicates that curcumin has an inhibitory effect on SDF-1alpha-induced HREC migration. The plausible mechanism of action could be upstream blockage of Ca(2+) influx and the downstream reduction of PI3-K/AKT signals.

Advanced glycation index and its association with severity of diabetic retinopathy in type 2 diabetic subjects.

BACKGROUND: This study investigates the association of advanced glycation index (AGI), a simple assay to detect advanced glycation endproducts (AGEs) in serum, with severity of diabetic retinopathy (DR) in type 2 diabetic subjects. METHODS: The study included 188 type 2 diabetic subjects without DR, 153 subjects with nonproliferative DR, 41 subjects with proliferative DR, and 188 control participants. Serum levels of AGEs were monitored with a spectrofluorimeter by recording Maillard-specific fluorescence. RESULTS: AGI values increased with severity of DR (analysis of variance, P<.0001). Among diabetic subjects, AGI (mean+/-S.E.) was higher among subjects with nonproliferative diabetic retinopathy (NPDR; 6.7+/-0.1 U) and proliferative diabetic retinopathy (PDR; 9.1+/-0.3 U) than among subjects without DR (P<.0001). By arranging the levels of serum AGI in quartiles, the proportion of PDR subjects increased with increasing AGI values, with maximum subjects in the last quartile (trend chi(2)=60.239, P<.0001). AGI was associated with NPDR even after adjusting for age, gender, duration of diabetes, and glycated hemoglobin [odds ratio (OR)=1.33; 95% confidence interval (95% CI)=1.12-1.57; P=.001]. Similarly, AGI showed a significant association with PDR even after adjusting for various risk factors (OR=2.47; 95% CI=1.75-3.47; P<.0001). Receiver-operating-characteristics curve analysis revealed that the threshold level of 8.07 U had a 78% sensitivity, an 83.6% specificity, and an 86.1% accuracy for detecting PDR. CONCLUSION: AGI showed a significant association with the severity of DR and, hence, could be used as a prognostic tool to predict the development and progression of DR.

Oxidative DNA damage and augmentation of poly(ADP-ribose) polymerase/nuclear factor-kappa B signaling in patients with type 2 diabetes and microangiopathy.

Although oxidative stress and the subsequent DNA damage is one of the obligatory signals for poly(ADP-ribose) polymerase (PARP) activation and nuclear factor-kappa B (NFkappaB) alterations, these molecular aspects have not been collectively examined in epidemiological and clinical settings. Therefore, this study attempts to assess the oxidative DNA damage and its downstream effector signals in peripheral blood lymphocytes from Type 2 diabetes subjects without and with microangiopathy along with age-matched non-diabetic subjects. The basal DNA damage, lipid peroxidation and protein carbonyl content were significantly (p<0.05) higher in patients with and without microangiopathy compared to control subjects. Formamido Pyrimidine Glycosylase (FPG)-sensitive DNA strand breaks which represents reliable indicator of oxidative DNA damage were also significantly (p<0.001) higher in diabetic patients with (19.41+/-2.5) and without microangiopathy (16.53+/-2.0) compared to control subjects (1.38+/-0.85). Oxidative DNA damage was significantly correlated to poor glycemic control. PARP mRNA expression and PARP activity were significantly (p<0.05) increased in cells from diabetic patients with (0.31+/-0.03 densitometry units; 0.22+/-0.02PARPunits/mgprotein, respectively) and without (0.35+/-0.02; 0.42+/-0.05) microangiopathy compared to control (0.19+/-0.02; 0.11+/-0.02) subjects. Diabetic subjects with and without microangiopathy exhibited a significantly (p<0.05) higher (80%) NFkappaB binding activity compared to control subjects. In diabetic patients, FPG-sensitive DNA strand breaks correlated positively with PARP gene expression, PARP activity and NFkappaB binding activity. This study provides a comprehensive molecular evidence for increased oxidative stress and genomic instability in Type 2 diabetic subjects even prior to vascular pathology and hence reveals a window of opportunity for early therapeutic intervention.

Prevalence and risk factors of diabetic nephropathy in an urban South Indian population: the Chennai Urban Rural Epidemiology Study (CURES 45).

OBJECTIVE: The aim of this study was to determine the prevalence of diabetic nephropathy among urban Asian-Indian type 2 diabetic subjects. RESEARCH DESIGN AND METHODS: Type 2 diabetic subjects (n = 1,716), inclusive of known diabetic subjects (KD subjects) (1,363 of 1,529; response rate 89.1%) and randomly selected newly diagnosed diabetic subjects (NDD subjects) (n = 353) were selected from the Chennai Urban Rural Epidemiology Study (CURES). Microalbuminuria was estimated by immunoturbidometric assay and diagnosed if albumin excretion was between 30 and 299 microg/mg of creatinine, and overt nephropathy was diagnosed if albumin excretion was > or = 300 microg/mg of creatinine in the presence of diabetic retinopathy, which was assessed by stereoscopic retinal color photography. RESULTS: The prevalence of overt nephropathy was 2.2% (95% CI 1.51-2.91). Microalbuminuria was present in 26.9% (24.8-28.9). Compared with the NDD subjects, KD subjects had greater prevalence rates of both microalbuminuria with retinopathy and overt nephropathy (8.4 vs. 1.4%, P < 0.001; and 2.6 vs. 0.8%, P = 0.043, respectively). Logistic regression analysis showed that A1C (odds ratio 1.325 [95% CI 1.256-1.399], P < 0.001), smoking (odds ratio 1.464, P = 0.011), duration of diabetes (1.023, P = 0.046), systolic blood pressure (1.020, P < 0.001), and diastolic blood pressure (1.016, P = 0.022) were associated with microalbuminuria. A1C (1.483, P < 0.0001), duration of diabetes (1.073, P = 0.003), and systolic blood pressure (1.031, P = 0.004) were associated with overt nephropathy. CONCLUSIONS: The results of the study suggest that in urban Asian Indians, the prevalence of overt nephropathy and microalbuminuria was 2.2 and 26.9%, respectively. Duration of diabetes, A1C, and systolic blood pressure were the common risk factors for overt nephropathy and microalbuminuria.

Effect of curcumin on proliferation of human retinal endothelial cells under in vitro conditions.

PURPOSE: To investigate the effect of high glucose on the proliferation of human retinal endothelial cells (HRECs) and to elucidate the possible mechanisms of antiangiogenic activity of curcumin, a diferuloylmethane. METHODS: Human retinal endothelial cells were isolated from the retinal tissue obtained from human donors and the culture system was established. The effect of curcumin on the proliferation of primary HRECs in the presence of low and high glucose was measured by MTT and thymidine uptake assays. Apoptosis was assessed by TUNEL assay and other adjuvant tools. Effect of curcumin on phorbol ester stimulated intracellular reactive oxygen species (ROS) generation in high glucose conditions was assessed by fluorescence assay. Finally, semiquantitative RT-PCR and Western blot analysis was performed to measure VEGF mRNA production and VEGF induced PKC-betaII translocation, respectively in the presence and absence of curcumin. RESULTS: HREC culture was established successfully at passages 3 and 4 at 80% confluence. Curcumin effectively inhibited endothelial cell proliferation in a dose-dependent manner. At a concentration of 10 microM, curcumin significantly inhibited HREC proliferation in high-glucose-treated cells, as verified by both MTT and thymidine uptake assay. Curcumin also showed a significant (P = 0.03) reduction of intracellular ROS generation in HRECs. RNA expression studies showed that curcumin had an inhibitory effect on the glucose-induced VEGF mRNA expression. In addition, VEGF-mediated, membrane-associated changes in the PKC-betaII translocation in HRECs was inhibited by 31% on treatment with 10 microM curcumin. CONCLUSIONS: These data suggest an underlying mechanism whereby curcumin induces the apoptosis in HRECs by the regulation of intracellular ROS generation, VEGF expression and release, and VEGF-mediated PKC-betaII translocation.

Association of hypoglutathionemia with reduced Na+/K+ ATPase activity in type 2 diabetes and microangiopathy.

OBJECTIVE: Although recent studies link altered cellular redox state to protein dysfunction in various disease-states, such associations are least studied in clinical diabetes. Therefore, this study assessed the levels of reduced glutathione (GSH) and Na(+)/K(+) ATPase activities in type 2 diabetic patients with and without microangiopathy. METHODS: The study group comprised of a total of 160 subjects, which included non-diabetic healthy controls (n = 40) and type 2 diabetic patients without (n = 60) and with microangiopathy (n = 60), defined as presence of retinopathy with or without nephropathy. Erythrocyte Na(+)/K(+) ATPase activity and GSH levels were estimated spectrophotometrically and fluorometry was used to determine the plasma thiobarbituric acid reactive substances (TBARS) and serum advanced glycation end products (AGEs). RESULTS: GSH levels in diabetic subjects without (4.8+/- 0.15 mumol/g Hb) and with microangiopathy (5.2+/- 0.14 micromol/g Hb) were significantly lower (p < 0.001) compared to control subjects (6.3 +/- 0.14 mumol/g Hb). Erythrocyte Na(+)/K(+) ATPase activity was significantly reduced (p < 0.001) in diabetes subjects with (272 +/- 7 nmol Pi/mg protein/h) and without microangiopathy (304 +/- 8) compared to control (374 +/- 6) subjects. TBARS were significantly higher (p < 0.001) in diabetes subjects with (10.65 +/- 0.81 nM/ml) and without microangiopathy (9.90 +/- 0.5 nM/ml) compared to control subjects (5.18 +/- 0.18 nM/ml). Advanced glycation end product levels were also significantly (p < 0.001) elevated in diabetic subjects with microangiopathy (8.2+/- 1.8 AU) when compared to diabetes subjects without microangiopathy (7.0 +/- 2.0 AU) and control subjects (4.6 +/- 1.9 AU). On multivariate regression analysis, GSH levels showed a positive association with the Na(+)/K(+) ATPase activity and negative association with TBARS and AGE levels. CONCLUSION: Hypoglutathionemia and increased oxidative stress appears to be early biochemical aberrations in diabetes, and through protein alterations, oxidative stress and redox modifications may contribute to pathogenesis of diabetic microangiopathy.

A novel advanced glycation index and its association with diabetes and microangiopathy.

Formation of advanced glycation end products (AGEs) is an important mechanism by which chronic exposure to high glucose levels leads to vascular complications. Measurement of AGEs is hence of great importance for clinicians and researchers concerned with the management and prevention of diabetic vascular disease. The aim of this study was to evaluate a simple methodology to detect AGEs in the serum and to correlate their levels with diabetes and microangiopathy, specifically retinopathy and nephropathy. We studied 157 subjects, which included nondiabetic control subjects (n = 38), type 2 diabetic patients without microangiopathy (n = 65), and type 2 diabetic subjects with retinopathy (n = 29) or both retinopathy and nephropathy (n = 25). All subjects were assessed for their glycemic and lipid status. Serum AGEs were monitored by recording the Maillard-specific fluorescence that resulted from sequential addition of serum into the buffer. The resultant linear regression was modeled to yield the slope values that were termed advanced glycation index (AGI) in arbitrary units. The serum levels of AGI (mean +/- SD) were higher in diabetic subjects without complications (6.0 +/- 1.6 units) compared with nondiabetic subjects (4.6 +/- 1.0 units), still higher among diabetic subjects with retinopathy (7.6 +/- 1.2 units) and highest in diabetic subjects with both retinopathy and nephropathy (8.3 +/- 2.0 units). Among diabetic subjects, AGI had a significant positive correlation with duration of diabetes (r = 0.25, P = .006), glycated hemoglobin (r = 0.27, P = .004), cholesterol (r = 0.24, P = .009), triglycerides (r = 0.23, P = .014), and serum creatinine (r = 0.30, P = .001), and a significant negative correlation with creatinine clearance (r = -0.27, P = .003). Logistic regression analysis using diabetic microangiopathy as the dependent variable showed an association with AGI even after including age, duration of diabetes, and glycated hemoglobin (P < .001) into the model. Advanced glycation index is a simple method to detect AGEs, and it correlates well with diabetes, particularly with microangiopathy.

Increased glutathionylated hemoglobin (HbSSG) in type 2 diabetes subjects with microangiopathy.

OBJECTIVE: Protein glutathionylation is considered an important post-translational modification in the pathogenesis of complex diseases. The aim of this study was to examine whether hemoglobin (Hb) is modified by reduced glutathione (GSH) via oxidation of the thiol groups present in diabetes and its associated microangiopathy and to determine whether oxidative imbalance has any correlation with glutathionylated Hb (HbSSG) levels. METHODS: The study group consisted of a total of 130 subjects which included non-diabetic healthy control subjects (n = 30) and type 2 diabetic patients with (n = 53) and without (n = 47) microangiopathy. All subjects were assessed for glycemic and lipidemic status, while diabetic subjects were also assessed for the diagnosis of retinopathy and nephropathy. RBC lysates from all the subjects were analyzed by liquid chromatography/electrospray ionization-mass spectrometry (LC/ESI-MS) for HbSSG beta-globin chains. Levels of GSH and thiobarbituric acid substances (TBARS) levels were measured by spectrophotometric and fluorimetric methods, respectively. RESULTS: The positivity for HbSSG in diabetic subjects with microangiopathy was significantly higher (69%) compared to diabetics without microangiopathy (22%) and control subjects (14%). In univariate regression analysis, HbSSG levels were significantly associated with the duration of diabetes, HbA1c, and TBARS levels. GSH levels were negatively correlated (r = -0.57, P < 0.001) with HbSSG in diabetic subjects. A significant inverse correlation (r = -0.42, P < 0.001) between the GSH levels and HbA1c levels was also seen in diabetic subjects. CONCLUSIONS: This is perhaps the largest LC-MS-based study to demonstrate that HbSSG levels are markedly increased in diabetic subjects with microangiopathy. Since diabetic subjects also exhibited increased lipid peroxidation and decreased GSH levels, it appears that enhanced oxidative stress may account for the increased HbSSG concentrations and altered reduction-oxidation (redox) signaling.

Visual outcomes of pan-retinal photocoagulation in diabetic retinopathy at one-year follow-up and associated risk factors.

PURPOSE: To assess the visual outcomes at one-year follow-up after pan-retinal photocoagulation (PRP) in type 2 diabetes mellitus subjects with proliferative diabetic retinopathy (PDR) and associated risk factors. MATERIALS AND METHODS: A retrospective study, using data from medical records of 5000 Type 2 diabetic patients who underwent a retinal examination between 1995 and 1999 at a diabetic centre. Ocular, clinical and biochemical parameters were assessed at baseline and at one-year follow-up after PRP. Diabetic retinopathy (DR) was documented by colour photography and PRP was performed according to the ETDRS criteria. RESULTS: PRP was done in 413 eyes, of which 261 eyes of 160 subjects were eligible for the study. One hundred and forty eyes (73%) of 191 eyes with good visual acuity (6/9) at baseline maintained the same vision at one-year follow-up. Of the 53 eyes with visual acuity of 6/12-6/36 at baseline, 58.5% (31 eyes) maintained same vision and 18.9% (10 eyes) improved their vision at one-year follow-up. Of the 17 eyes with visual acuity < or =6/60 at baseline, 12 maintained the same vision and the remaining 5 improved their vision. The causes of visual loss included vitreous haemorrhage in 20 subjects (31.7%), progression of cataract in 19 (30%), chronic macular oedema in 15 (23.8%), pre-retinal haemorrhage in the macula in 6 (9.5%) and pre-retinal fibrosis in the macula in 3 (4.7%) subjects. On multiple logistic regression analysis, diastolic blood pressure (P =0.03), duration of diabetes (P =0.006), fasting blood glucose (P =0.02) and nephropathy (P =0.01) were associated with decreased vision after PRP. Glycated haemoglobin (HbA1c) (P < 0.001), serum creatinine (P =0.03), HDL cholesterol (P =0.05), diabetic neuropathy (P < 0.001), hypertension (P =0.01) and diabetic nephropathy (P < 0.001) showed a significant association with PDR. CONCLUSION: Visual acuity at baseline, the duration of diabetes and proteinuria played a significant role in determining the post-PRP visual acuity.

Prevalence of diabetic retinopathy in urban India: the Chennai Urban Rural Epidemiology Study (CURES) eye study, I.

PURPOSE: To assess the prevalence of diabetic retinopathy (DR) in type 2 diabetic subjects in urban India using four-field stereo color photography. METHODS: The Chennai Urban Rural Epidemiology Study (CURES) is a population-based study conducted on a representative population of Chennai (formerly Madras) city in South India. Individuals > or =20 years in age (n = 26,001) were screened for diabetes. Of the 1529 known diabetic subjects, 1382 (90.4%) participated in the study. Subjects with newly detected diabetes (n = 354) by the oral glucose tolerance test (OGTT) also consented to participate in the study. All the subjects underwent four-field stereo color photography, and retinopathy was graded in the color fundus photographs according to Early Treatment Diabetic Retinopathy Study (ETDRS) criteria. RESULTS: The overall prevalence of DR in the population was 17.6% (95% confidence interval [CI]: 15.8-19.5), which included 20.8% (95% CI: 18.7-23.1) in known diabetic subjects and 5.1% (95% CI: 3.1-8.0) in subjects with newly detected diabetes. The prevalence of DR was significantly higher in men than in women (21.3% vs. 14.6%; P < 0.0001) and among subjects with proteinuria (P = 0.002). Logistic regression analysis showed that for every 5-year increase in the duration of diabetes, the risk for DR increased 1.89-fold (95% CI: 1.679-2.135; P < 0.0001). For every 2% elevation of glycated hemoglobin (HbA1c), the risk for DR increased by a factor of 1.7 (95% CI: 1.545-1.980; P < 0.0001). CONCLUSIONS: This study shows that the prevalence of diabetic retinopathy is lower in urban South Indians than in other ethnic groups. However, due to the large number of diabetic subjects, DR is likely to pose a public health burden in India; hence, routine retinal examination is mandatory to detect DR in the early stages.

Prevalence of diabetic complications in fibrocalculous pancreatic diabetic patients and type 2 diabetic patients: a cross-sectional comparative study.

OBJECTIVE: To determine the prevalence of diabetes-related complications in subjects with fibrocalculous pancreatic diabetes (FCPD) and compare them with subjects with type 2 diabetes mellitus matched for age, sex, and duration of diabetes. METHODS: The study group comprised of 277 FCPD patients and 277 age, sex, and duration of diabetes-matched type 2 diabetic patients. All the study subjects underwent a detailed clinical examination, and fasting blood samples were obtained for biochemical studies. Peripheral Doppler was used for diagnosis of peripheral vascular disease (PVD). Vibratory perception threshold (VPT) was determined using biothesiometry for diagnosis of neuropathy. Diagnosis of coronary artery disease (CAD) was based on medical history and 12-lead resting ECG. Retinal photographs were used for diagnosis of retinopathy using a modified version of Early Treatment Diabetic Retinopathy Study (ETDRS) grading system. RESULTS: FCPD patients had lower body mass index (BMI) (P<.001), systolic blood pressure (P<.0001), diastolic blood pressure (P<.001), serum cholesterol (P<.001), serum triglyceride (P<.001), and serum creatinine (P<.01) but higher glycosylated hemoglobin (P<.001) levels compared to patients with type 2 diabetes. Prevalence of CAD was significantly higher among type 2 diabetic patients (11.9%) compared to FCPD patients (5.1%), P<.003. There was no significant difference in the prevalence of other diabetic complications between the two study groups (type 2 diabetes vs. FCPD: retinopathy-37.2% vs. 30.1%, PVD-4.3% vs. 4.7%, Neuropathy-25.3% vs. 20.9%, Nephropathy-15.0% vs. 10.1%). Multiple logistic regression analysis revealed the following risk factors for diabetes complications among type 2 diabetic subjects-retinopathy: BMI (P=.028), duration of diabetes (P<.001), and glycosylated hemoglobin (P=.026); nephropathy: diastolic blood pressure (P=.016) and glycosylated hemoglobin (P=.040); neuropathy: age (P<.001), duration of diabetes (P=.003), and glycosylated hemoglobin (P=.001). Among subjects with FCPD, systolic blood pressure (P=.013), glycosylated hemoglobin (P=.021), and duration of diabetes (P<.001) were associated with retinopathy; BMI (P=.057), glycosylated hemoglobin (P=.010), and duration of diabetes (P=.024) with nephropathy and age (P=.011) and BMI (P=.010) with neuropathy. CONCLUSION: The prevalence of retinopathy, nephropathy, neuropathy, and PVD was similar among FCPD patients and type 2 diabetic patients, but the prevalence of CAD was lower among FCPD patients.

Association of carotid intima-media thickness and arterial stiffness with diabetic retinopathy: the Chennai Urban Rural Epidemiology Study (CURES-2).

OBJECTIVE: The aim of this study was to assess the association of intima-media thickness (IMT) and arterial stiffness with diabetic retinopathy in an Asian-Indian population that has very high prevalence rates of diabetes and coronary artery disease. RESEARCH DESIGN AND METHODS: The study was conducted on 600 type 2 diabetic subjects randomly selected from the Chennai Urban Rural Epidemiology Study (CURES), which is an ongoing population-based study of a representative population of Chennai. When present, retinopathy was graded according to a modified Early Treatment Diabetic Retinopathy Study grading system. IMT was determined using high-resolution B-mode ultrasonography. Arterial stiffness was measured by assessing the augmentation index (AI) using the Sphygmocor apparatus. RESULTS: Retinopathy was diagnosed in 116 of 590 (19.6%) subjects in whom retinal photography was possible. Mean values of IMT (0.93 +/- 0.36 vs. 0.85 +/- 0.21 mm, P = 0.001) and AI (27.9 +/- 8.9 vs. 25.8 +/- 9.6%, P = 0.031) were significantly higher among diabetic subjects with retinopathy compared with those without. Both IMT (P = 0.024) and AI (P = 0.050) showed a significant association to diabetic retinopathy, even after adjusting for age, duration of diabetes, HbA(1c), serum cholesterol, serum triglycerides, and microalbuminuria. CONCLUSIONS: Diabetic retinopathy is associated with IMT and AI, suggesting that common pathogenic mechanisms might predispose to diabetic micro- and macroangiopathy.

Genes and diabetic retinopathy.

Several recent studies have provided evidence that good diabetes control is important to prevent diabetic retinopathy. However, some groups of patients develop diabetic retinopathy despite good control and others escape retinopathy despite poor control. This suggests the role of genetic factors in susceptibility to retinopathy. This article reviews the role of genetic factors in determining diabetic retinopathy.