Statistical Methods for Best and Worst Eye Measurements.

Introduction: The focus is often on the best and worst eyes to detect early predictive and non-invasive biomarkers of diabetic retinopathy. Typically, such data have been dealt with in a case-control setting, which applies two-sample tests and ignores the correlation between the fellow eyes. Practitioners are mostly unaware that such measurements hide the labels of the fellow eyes, which rules out standard tools, such as paired t or signed-rank tests. Methods: This report discusses the problems with such data on best and worst eye measurements, and illustrates alternative paired tests for equality of means or locations using a case-control dataset. Results: This report illustrates that methods which ignore the correlation between fellow eyes result in grossly conservative tests. A battery of Z-tests which consider this correlation can resolve this issue. Discussion: This finding emphasizes the importance of selecting an appropriate control group for the detection of possible markers. Further, it cites an example to show that using data from fellow eyes and adjusting for their correlation may not always be the best option, contrary to common perception.

Biosimilar candidate CT-P42 in diabetic macular edema: 24-week results from a randomized, active-controlled, Phase III study.

OBJECTIVE: To demonstrate the therapeutic similarity of CT-P42 compared to reference aflibercept (Eylea®) in adult patients with diabetic macular edema (DME). DESIGN: Randomized, active-controlled, double-masked, Phase III clinical trial PARTICIPANTS: Patients with a diagnosis of either type 1 or 2 diabetes mellitus (DM) with DME involving the center of the macula. METHODS: Patients were randomized (1:1) to receive either CT-P42 or reference aflibercept (2 mg/0.05 mL) by intravitreal injection every 4 weeks (5 doses) then every 8 weeks (4 doses) in the main study period. Results up to Week 24 are reported herein. MAIN OUTCOME MEASURES: The primary endpoint was mean change from baseline at Week 8 in best corrected visual acuity (BCVA) using the Early Treatment Diabetic Retinopathy Study (ETDRS) chart. Equivalence between CT-P42 and reference aflibercept was to be concluded if the two-sided 95% confidence interval (CI) (global assumptions) and two-sided 90% CI (US Food and Drug Administration [FDA] assumptions) for the treatment difference fell entirely within the equivalence margin of ±3 letters, as assessed in the full analysis set. RESULTS: Overall, 348 patients were randomized (CT-P42: 173; reference aflibercept: 175). BCVA improved from baseline to Week 8 in both groups, with a least squares mean (standard error) improvement of 9.43 (0.798) and 8.85 (0.775) letters in the CT-P42 and reference aflibercept groups, respectively. The estimated between-group treatment difference was 0.58 letters, with the CIs within the pre-defined equivalence margin of ±3 letters (95% CI -0.73, 1.88 [global]; 90% CI -0.52, 1.67 [FDA]). Through Week 24, other efficacy results for the two groups, in terms of change in BCVA and retinal central subfield thickness, as well as ETDRS Diabetic Retinopathy Severity Scale score, supported therapeutic similarity. Pharmacokinetics, usability, safety (including the proportions of patients experiencing at least one treatment-emergent adverse event [CT-P42: 50.3%; reference aflibercept: 53.7%]), and immunogenicity were also comparable between groups. CONCLUSIONS: This study in patients with DME demonstrated equivalence between CT-P42 and reference aflibercept (2 mg/0.05 mL) in terms of efficacy, with similar pharmacokinetic, usability, safety, and immunogenicity profiles.

Effects of Lunar Phases on Foot Temperature, Oxidative Stress, and Inflammation in Type 2 Diabetic Subjects.

BACKGROUND: It has been observed that the lunar phases alter the fasting plasma glucose (FPG) level in type-2 diabetic (T2DM) subjects. Diabetic peripheral neuropathy (DPN) was also reported to be associated with elevated foot temperature (FT), oxidative stress, and inflammation in T2DM subjects. OBJECTIVES: The purpose of the present study was to evaluate the changes in FT, oxidative stress, and inflammation levels and assess the relationship of FT with oxidative stress, antioxidant enzyme activity, and inflammatory markers in T2DM subjects at different lunar phases. METHODS: The plasma glucose, glycated hemoglobin, and dorsal and plantar surface temperatures of the feet by infrared dermal thermometer were measured in 88 randomly selected T2DM subjects at different lunar phases. The levels of oxidative stress and inflammation were assessed by measuring malondialdehyde (MDA), glucose 6-phosphate dehydrogenase (G6PDH), and tumor necrosis factoralpha (TNF-α). RESULTS: The FTs, MDA, and TNF-α were significantly increased, and G6PDH activity was significantly decreased in the new moon (NM) and full moon (FM) than in the third quarter (TQ) and first quarter (FQ) for both sexes. The FTs, MDA, and TNF-α levels were significantly positively correlated, whereas G6PDH activity was significantly negatively correlated with FPG at NM and FM in both sexes. The MFT was significantly positively correlated with MDA and TNF-α and significantly negatively correlated with G6PDH at NM and FM in T2DM subjects. CONCLUSION: The lunar phases showed a prominent influence on the FT, oxidative stress, and inflammatory status in T2DM subjects, which might be due to the existence of biological rhythm interaction with lunar electromagnetic radiations.

The Amelioration of Detrimental Biochemical Anomalies by Supplementing B, C, and E Vitamins in Subjects with Type 2 Diabetes Mellitus May Reduce the Rate of Development of Diabetic Retinopathy.

Excessive intracellular glucose in insulin-independent tissues including nerve, nephron, lens, and retina invites mishandling of metabolism of glucose resulting in a background of increased oxidative stress, advanced glycation end products (AGE) formation, lipid peroxidation, and failure of antioxidant defense systems in type 2 diabetes mellitus (T2DM). All these detrimental biochemical anomalies ultimately attack biological membranes and especially capillary beds of the retina, resulting in the breakdown of the inner blood-retinal barrier and the initiation of diabetic retinopathy (DR). If these disarrays are corrected to a large extent, the development of DR can be avoided or delayed. In this prospective clinical trial, 185 patients with T2DM who received B vitamins, vitamin C, and vitamin E along with antidiabetic medication for five years demonstrated a slower rate of the development of DR and reduced abnormal biochemical mediators like reactive oxygen species (ROS), malondialdehyde (MDA), AGE, and vascular endothelial growth factor (VEGF) compared to 175 T2DM individuals who were treated with only antihyperglycemic drugs.

Do different lipid components accelerate the pathogenesis and severity of Diabetic Retinopathy?

BACKGROUND: To assess the association of lipid and lipid-derived toxic molecules in pathogenesis and severity of diabetic retinopathy (DR) in type 2 diabetes mellitus (T2DM). METHODS: The present cross-sectional study included 14 healthy individuals (HC) without T2DM, 22 T2DM subjects without DR (DNR), 24 T2DM subjects with mild non-proliferative DR (MNPDR), and 24 T2DM subjects with high-risk proliferative DR (HRPDR). All subjects underwent plasma and vitreous analysis for estimation of total lipid (TL), free fatty acid (FFA), lipid peroxides (LPOs) like malondialdehyde (MDA), 4-Hydroxy-noneal (HNE), the advanced lipoxidation end product (ALE) like Hexanoyl-lysine (HLY) and vascular endothelial growth factor (VEGF) following standard spectrophotometric and enzyme-linked immunosorbent assay (ELISA) methods respectively. RESULTS: The concentration of TL, FFA, markers of lipid peroxidation and lipoxidation as well as VEGF in plasma and vitreous were found to be significantly elevated stepwise inT2DM subjects (HRPDR > MNPDR > DNR) compared to healthy controls (HC).Further, plasma conventional lipid components like total cholesterol (TCH), low density lipoprotein cholesterol (LDL-C) and triglycerides (TG), FFA and TL showed their significant positive correlations with vitreous level of different LPOs, ALE and VEGF in the DR group. CONCLUSION: Total lipid and lipid-derived detrimental biomolecules ultimately result in increased secretion of VEGF and thus not only add as associated mediators in the pathogenesis of DR, these also accelerate the severity of microangiopathy in T2DM.

Decreased Levels of miR-126 and miR-132 in Plasma and Vitreous Humor of Non-Proliferative Diabetic Retinopathy Among Subjects with Type-2 Diabetes Mellitus.

PURPOSE: Diabetic retinopathy (DR), the leading cause of blindness among working adults, is an urgent public health problem as diabetes mellitus (DM) is increasing at an alarming rate. Hyperglycemia-induced endothelial dysfunction is the principal contributing factor leading to the development of microangiopathy. Altered levels of microRNA (miR), the negative regulator of protein-coding genes, have been observed and considered to be markers for DR. Present study aimed to find out whether miR levels in plasma could be effective biomarkers to differentiate between type 2 diabetes mellitus (T2DM) with non-proliferative retinopathy (NPDR) from T2DM with no-DR (DNR). METHODS: We recruited 50 T2DM subjects comprising 31 NPDR and 19 DNR individuals. Surrogate markers of systemic oxidative stress and vascular endothelial growth factor (VEGF) were measured in plasma. Levels of miR-126 and miR-132 were determined in plasma and vitreous fluid using real-time PCR. RESULTS: We observed that levels of miR-126 and miR-132 were decreased in NPDR subjects in comparison to DNR. Plasma levels of miRs were inversely correlated with secreted levels of VEGF and oxidative stress marker. The levels of these miRs showed discriminating ability between NPDR and DNR. CONCLUSION: Circulating miRs 126 and 132 in plasma or vitreous may serve as biomarkers for early diabetic retinopathy risk prediction, provided validated in a larger cohort and other forms of retinal vasculopathy or retinopathy in the future.

Efficacy and Cost-Effectiveness of Anti-VEGF for Treating Diabetic Retinopathy in the Indian Population.

PURPOSE: In the present study, we aimed to evaluate the efficacy, safety, and cost-effectiveness of the anti-vascular endothelial growth factor (anti-VEGF), namely ranibizumab (RBZ) or bevacizumab (BVZ), after either focal or grid or scatter laser photocoagulation, for the treatment of diabetic macular edema (DME) in the Indian population. METHODS: Retrospective data were collected in the Regional Institute of Ophthalmology, Kolkata, India between January 2018 and June 2019. Seventy-seven eyes received 3 consecutive monthly intravitreal injections of RBZ (0.5 mg) and were followed by prompt laser photocoagulation (within 7-10 days after the third injection). Similarly, 51 eyes received 3 consecutive monthly intravitreal injections of BVZ (1.25 mg), an off-label drug, and were followed by prompt laser therapy. Safety assessments of the therapy, as well as surrogate markers of biochemical derangements related to diabetic retinopathy (DR), were also investigated at the end of 12 months. RESULTS: Seventy-seven subjects who were given a treatment of RBZ+laser therapy showed average 6.87±5.53 letters gain in their best-corrected visual acuity (BCVA) score, whereas the ones treated with off-label BVZ+ laser therapy demonstrated improvement in BCVA of an average 6.82±5.76 letters in "Early Treatment Diabetic Retinopathy Study" (ETDRS) chart. The study also highlights the cost-effectiveness of both RBZ+laser and BVZ+laser therapies for the treatment of DME in DR. The results demonstrated that a subject has to pay 20.951 times more cost (in INR) for RBZ+laser therapy compared to BVZ+laser therapy, to get an almost similar outcome. CONCLUSION: BVZ is found to be the more attractive option for treating DME in DR for its cost-friendliness over RBZ in terms of BCVA outcome, as well as the safety perspectives, at least for the economically backward population in developing countries, like India.

Effects of lunar cycle on fasting plasma glucose, heart rate and blood pressure in type 2 diabetic patients.

The purpose of this study was to investigate the influence of lunar phases on fasting plasma glucose, heart rate, and blood pressure in type 2 diabetic patients. The present cross-sectional study was carried out during four phases, i.e., full moon (FM), first quarter (FQ), new moon (NM), and third quarter (TQ), of the lunar month. The study was conducted on 42 randomly selected patients (22 males and 20 females) from the Diabetes Clinic of Calcutta Medical College. Fasting plasma glucose (FPG) of each subject was determined and heart rate (HR) and blood pressure (BP) were measured at rest and during static exercise conditions, i.e., performance of a standard handgrip dynamometer test. The FPG level during the NM and FM was significantly higher (p < .001) than during the TQ and FQ for both males and females, respectively. The mean HR during static exercise during the NM and FM for both males and females was significantly higher than that during the FQ (p < .05) and TQ (p < .01). It appears from the present study that lunar phases may affect fasting plasma glucose level and cardiovascular functions of aged type 2 diabetic patients both at rest and during exercise.

Visual contrast sensitivity could be an early marker of diabetic retinopathy.

The present study aimed to explore the early predictive marker of diabetic retinopathy (DR) and to elucidate the associated demographic, metabolic, and ocular factors. We enrolled 43 type 2 diabetic subjects with mild non-proliferative retinopathy (MNPDR), 30 diabetic subjects with no retinopathy (DNR), and 35 healthy controls (HC). The study groups showed no significant alteration in central macular thickness (CMT) and visual acuity (VA). The contrast sensitivity (CS) score was found to be significantly lower among DNR and MNPDR subjects compared to HCs (p < 0.0001). Between MNPDR and DNR subjects, the CS score was significantly lower in the former (p = 0.0036). CS score discriminated DNR subjects from HC, with 74% accuracy for the optimal threshold 0.71. The associated area under the ROC curve (AUC) is 0.82 (p < 0.0001) while the discrimination rule has 66% sensitivity and 80% specificity. The CS score also discriminated MNPDR subjects from DNR with 64% accuracy for the optimal threshold 0.53. The associated AUC is 0.65 (p < 0.023) and the rule has 86% sensitivity and 33% specificity. According to best subset regression analysis, not only glycaemic parameters but also lipid parameters [low-density lipoprotein cholesterol (LDL-C) (p = 0.045) and triglycerides (TG) (p = 0.0005)] were found to be significant predictors of CS. CMT (p = 0.058) was another marginally significant predictor of CS. CS may be used as an early predictive marker for DR. So, not only hyperglycemia, but also hyperlipidemia seems to significantly affect retinal CS function in diabetes.

Biochemical scenario behind initiation of diabetic retinopathy in type 2 diabetes mellitus.

Purpose: Despite the disease having similar glycemic status and duration microangiopathy in some patients develop within few years whereas it doesn't appear as a health complication in some diabetics for a considerable period. This study is undertaken to assess the hyperglycemia-induced biochemical background behind the development of diabetic retinopathy (DR) in type 2 diabetes mellitus (DM). Methods: Following proper diagnosis, 100 patients of type 2 DM of 10-12 years duration having no DR, and 42 patients of type 2 DM of the same duration and glycemic status as the second group, with mild retinopathy were recruited in the study. Lactic acid, glutamate, malondialdehyde (MDA), nitrate, advanced glycation end-products (AGEs), peripheral blood mononuclear cell reactive oxygen species (ROS), vascular endothelial growth factor (VEGF), and its receptor 2 (VEGFR2) in these two groups were produced in an assay following standard methodology. Results: Biochemical markers of anaerobic glycolysis, lipid peroxidation, AGEs, glutamate concentration, oxidative stress, and expression of VEGF and its VEGFR2 with significantly elevated markings were found in them who developed earliest stage of DR rather than them who had not. Conclusion: Hyperglycemia-induced anomalous glucose metabolism, lipid peroxidation, advanced glycation, glutamate toxicity, and oxidative stress create a background where apoptosis of retinal capillary endothelial cells invite increased expression of VEGF and VEGFR2, these being the crucial factors behind the development of diabetic microangiopathy.

Hyperlipidemia-Mediated Increased Advanced Lipoxidation End Products Formation, an Important Factor Associated with Decreased Erythrocyte Glucose-6-Phosphate Dehydrogenase Activity in Mild Nonproliferative Diabetic Retinopathy.

OBJECTIVES: The present study aimed to evaluate the role of hyperlipidemia in increased formation of advanced lipoxidation end products (ALEs) and to evaluate whether there is any relationship between ALEs generation and erythrocyte glucose-6-phosphate dehydrogenase (G6PD) activity in cases of mild nonproliferative diabetic retinopathy (MNPDR). METHODS: In this study, we enrolled 100 patients with type 2 diabetes and MNPDR, 100 subjects with type 2 diabetes but without retinopathy (DNR) and 90 normal individuals without diabetes as healthy controls (HCs). Erythrocyte nicotinamide dinucleotide phosphate (NADPH), G6PD activity, serum total cholesterol, low- and high-density lipoprotein (LDL, HDL) and triglyceride levels were determined by photometric assay. Serum malondialdehyde (MDA) protein adduct and hexanoyl-lysine (HEL) were measured by an enzyme-linked immunosorbent assay (ELISA). RESULTS: A robust linear relationship was observed between MDA protein adduct and LDL or cholesterol or triglyceride levels, and HEL and LDL or cholesterol or triglyceride levels in subjects with MNPDR (p=0.0001). A significant inverse association was observed between erythrocyte G6PD activity and serum MDA protein adductor HEL levels in subjects with MNPDR (p=0.0001). CONCLUSIONS: Hyperlipidemia is an important factor that is associated with increased ALEs formation in persons with MNPDR. Increased ALEs generation was associated with decreased G6PD activity and low NADPH levels in cases of MNPDR, suggesting their detrimental role in the occurrence of early NPDR.

Role of N-ε- carboxy methyl lysine, advanced glycation end products and reactive oxygen species for the development of nonproliferative and proliferative retinopathy in type 2 diabetes mellitus.

PURPOSE: The aim of the present study was to evaluate the collective role of N-epsilon-carboxy methyl lysine (N(ε)-CML), advanced glycation end-products (AGEs), and reactive oxygen species (ROS) for the development of retinopathy among type 2 diabetic subjects. METHODS: Seventy type 2 diabetic subjects with nonproliferative diabetic retinopathy (NPDR), 105 subjects with proliferative diabetic retinopathy (PDR), and 102 patients with diabetes but without retinopathy (DNR) were enrolled in this study. In addition, 95 normal individuals without diabetes were enrolled as healthy controls in this study. Serum and vitreous N(ε)-CML and AGEs were measured by enzyme-linked immunosorbent assay. The peripheral blood mononuclear cell (PBMC) ROS level was measured by flow cytometric analysis. Serum and PBMC total thiols were measured by spectrophotometry. RESULTS: Serum AGEs and N(ε)-CML levels were significantly elevated in subjects with PDR (p<0.0001) and NPDR (p=0.0297 and p<0.0001, respectively) compared to DNR subjects. Further vitreous AGEs and N(ε)-CML levels were found to be significantly high among PDR subjects compared to the control group (p<0.0001). PBMC ROS production was found to be strikingly high among NPDR (p<0.0001) and PDR (p<0.0001) subjects as compared to the DNR group. Serum and PBMC total thiol levels were remarkably decreased in NPDR (p<0.0001 and p=0.0043, respectively) and PDR (p=0.0108 and p=0.0332 respectively) subjects than those were considered as DNR. CONCLUSIONS: Our findings suggest that N(ε)-CML and ROS are the key modulators for the development of nonproliferative retinopathy among poorly controlled type 2 diabetic subjects. Furthermore, AGEs under persistent oxidative stress and the deprived antioxidant state might instigate the pathogenic process of retinopathy from the nonproliferative to the proliferative state.

Association of vascular endothelial growth factor, transforming growth factor beta, and interferon gamma gene polymorphisms with proliferative diabetic retinopathy in patients with type 2 diabetes.

PURPOSE: Chronic hyperglycemia and hypoxemia are believed to be causal factors in the development of proliferative diabetic retinopathy (PDR) among individuals with type 2 diabetes. It is hypothesized that formation of new blood vessels in the retina due to prolonged hypoxia is associated with increased expression of several growth factors and angiogenic cytokines. In the present study, we investigated the association of genetic polymorphisms in vascular endothelial growth factor (VEGF), transforming growth factor beta (TGF-ß), and interferon γ (IFN-γ) genes, which may be responsible for the hypoxia-induced VEGF-mediated neovascularization pathway for the pathogenesis of PDR. METHODS: Our case-control association study composed of 493 ethnically matched volunteers (253 with PDR [cases] and 240 diabetic controls [DC]). Gene polymorphisms were determined with Taqman-based real-time PCR and amplification refractory mutation analysis system PCR. RESULTS: The VEGF-460C (rs833061C; p=0.0043) and IFN-γ +874T (rs2430561T; p=0.0011) alleles were significantly associated with PDR. CONCLUSIONS: Genetic variations at VEGF-460C and IFN-γ +874T might accelerate the pathogenesis of retinal neovascularization in PDR.

Increased Toll-like receptor-2 expression on nonclassic CD16+ monocytes from patients with inflammatory stage of Eales' disease.

PURPOSE: To identify the distribution, differential Toll-like receptor (TLR) expression, and functional contribution of monocyte subpopulations in the inflammatory stage of Eales' disease (ED). METHODS: Peripheral blood mononuclear cells were isolated from nine patients during the inflammatory stage of ED and nine age- and sex-matched healthy controls. The expression of CD14, CD16, TLR-2, and TLR-4 on monocytes was measured by flow cytometry. The CD14⁺, CD16⁻, and CD16⁺ monocyte populations were sorted on the basis of magnetic-activated cell-sorting methodology, and levels of cytokines were measured by ELISA. RESULTS: In ED patients, the number of circulating monocytes was significantly expanded compared with that in controls (P = 0.01), with a marked increase in the nonclassic CD16⁺ subset, which showed an activated phenotype in patients that correlated with levels of serum proinflammatory cytokines and clinical progression. A higher expression of cell surface TLR-2 (P = 0.02), but not TLR-4, was found in monocytes of patients with ED. Furthermore, TLR-2 was expressed at higher levels on CD16⁺ monocytes than on CD16⁻ monocytes in patients, whereas no significant variation was found in TLR-4 expression on different monocyte subsets. Peptidoglycan-induced TNF-α expression correlated with TLR-2 expression in monocytes isolated from controls (r = 0.85, P = 0.0061), but not in monocytes isolated from ED patients (r = 0.553, P = 0.1328). CONCLUSIONS: These results indicate that in the pathogenesis of ED, TLR activation and increased numbers of nonclassic CD16⁺ monocytes are crucial regulators, along with the secretion of proinflammatory cytokines that perpetuate the inflammatory process in the retina.

Association of interferon-gamma, interleukin-10, and tumor necrosis factor-alpha gene polymorphisms with occurrence and severity of Eales' disease.

PURPOSE: Eales' disease (ED) is an idiopathic retinal vasculitis characterized by capillary nonperfusion and neovascularization. Previous reports on ED demonstrated that T-cell-mediated immunoresponse and differential cytokine production in inflammatory and angiogenic stage seem to influence the extent and severity of this disease. Therefore, the purpose of this study is to investigate the influence of cytokine gene polymorphisms on occurrence and severity of ED. METHODS: One hundred twenty-one patients with ED were recruited from an Eastern Indian population and compared with 223 matched healthy control subjects. Genotyping of IFN-γ, IL-10, and TNF-α were performed by amplification refractory mutation system polymerase chain reaction (ARMS-PCR). RESULTS: A statistically significant association was found between the IL-10 -1082AA (P = 0.002), TNF-α -308AA (P = 0.0017) genotypes and the IL-10 ATA haplotype (P = 0.0123) and the occurrence of ED. In addition IL-10 -1082GG (P = 0.0005), TNF-α -308GG (P < 0.0001) genotype were found to be protective against disease occurrence. A synergistically low IL-10/high TNF-α genotype increased the risk of development (P < 0.0001) and the severity (P = 0.019) of ED. CONCLUSIONS: These data suggest that a low IL-10-expressing and high TNF-α-expressing genotype of the host can influence the occurrence and severity of outcome of ED.

Acute bilateral central serous chorioretinopathy following intra-articular injection of corticosteroid.

There is increasing evidence in the literature implicating the use of exogenous steroids through various routes as a risk factor for the development of idiopathic central serous chorioretinopathy (ICSC). We report a case of acute bilateral ICSC following intra-articular injection of corticosteroids.