[Show abstract][Hide abstract] ABSTRACT: PURPOSE:: To evaluate erythrocyte redox state and its surrogates in patients with different stages of diabetic retinopathy and their association with cellular metabolic derangement developed in retinal microvascular cells. METHODS:: Sixty type 2 diabetic patients with nonproliferative diabetic retinopathy (NPDR), 85 patients with proliferative diabetic retinopathy (PDR), and 70 patients with diabetes but without retinopathy were considered as diabetic control (DC) for the study. In addition, 65 normal individuals without diabetes were enrolled as healthy control in this study. Erythrocyte oxidized nicotinamide adenine dinucleotide phosphate / reduced nicotinamide adenine dinucleotide phosphate (NADP / NADPH), oxidized nicotinamide adenine dinucleotide / reduced nicotinamide adenine dinucleotide (NAD / NADH) glutathione, plasma and vitreous lactate, and pyruvate levels were determined by enzymatic reaction-based spectrophotometric assay for the patients and individuals. RESULT:: Erythrocyte NADP+ to NADPH ratio to NADPH ratio was found to be significantly higher among NPDR and PDR patients compared with DC subjects (P < 0.0001). Erythrocyte-reduced glutathione was significantly decreased in patients of NPDR (P = 0.0004) and patients of PDR (P = 0.0157) compared to DC. Erythrocyte nicotinarnide adenine dinucleotide positive to NADH ratio was also significantly decreased in patients of NPDR (P < 0.0001) and PDR (P < 0.0001) compared to DC subjects. Lactate to pyruvate ratio of plasma was elevated significantly in patients with NPDR compared with DC (P < 0.0001) and those having PDR (P = 0.0046). In the vitreous fluid, the lactate to pyruvate ratios were found to be significantly lower in normal individuals without diabetes compared with patients having PDR (P < 0.0001). CONCLUSION:: Hyperglycemia-mediated erythrocyte redox state alterations might be a potential risk factor for the development of NPDR in poorly controlled diabetic subjects.
[Show abstract][Hide abstract] ABSTRACT: To evaluate the role of interleukin-6 (IL-6) in the inflammatory and proliferative stages of Eales' disease (ED) and to determine the influence of IL-6-174G/C polymorphism in the IL-6 and IL-6-regulated protein expression, as well as the development of ED.
One hundred and twenty-one patients diagnosed with ED, 223 matched healthy controls, and 16 control patients with macular holes were recruited from the eastern Indian population. Serum and vitreous levels of IL-6 and vascular endothelial growth factors (VEGF) were measured by enzyme-linked immunosorbent assay. Serum levels of high-sensitivity C-reactive protein (hsCRP) were measured by enzyme immunoassay. Subjects were genotyped for the IL-6-174G/C polymorphism (rs1800795) by a custom TaqMan single-nucleotide polymorphism (SNP) Genotyping Assays system.
Serum IL-6 (p<0.0001), hsCRP (p<0.0001), and VEGF (p=0.0031) levels were significantly higher in the inflammatory stage of ED than in healthy controls. Serum IL-6 also significantly correlated with hsCRP (Spearman's correlation coefficient; r=0.4992, p=0.0009), but not with VEGF in this stage in ED patients. At the proliferative stage of ED, significantly higher levels of vitreous IL-6 (p=<0.0001) and VEGF (p=<0.0001) were found compared with the vitreous of patients with macular holes. A significant correlation was observed between vitreous IL-6 and VEGF in ED patients (Spearman's correlation coefficient; r=0.5834, p=0.0087). A statistically significant association was found between the -174GG genotype (p=0.006) and occurrence of ED. Mean serum and vitreous concentrations of IL-6 were also higher in the subjects with the GG genotype than in those with the GC or CC genotype in this population.
IL-6 expression, regulated by the allelic distribution of -174 loci and the enhanced level of IL-6, modulates CRP and VEGF concentration depending respectively on the acute inflammatory stimulation at the initial stage and angiogenic stimulation at the advanced stage of ED.
[Show abstract][Hide abstract] ABSTRACT: To identify the distribution, differential Toll-like receptor (TLR) expression, and functional contribution of monocyte subpopulations in the inflammatory stage of Eales' disease (ED).
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.
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).
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.
[Show abstract][Hide abstract] ABSTRACT: Eales disease (ED) is an idiopathic, inflammatory, venoocclusive disorder of peripheral retina resulting in retinal angiogenesis and vitreous hemorrhage. The objective of the present study is to investigate the expression and activation of gelatinase associated with the retinal neovascularization in ED and the relation between the levels of gelatinase and the cytokine tumor necrosis factor-α, known to upregulate matrix metalloproteinase (MMP) expression on various cells.
Vitreous and serum samples from 19 patients with ED who underwent retinal surgery were estimated for levels of MMP-2, MMP-9, tissue inhibitor of metalloproteinase-1, tissue inhibitor of metalloproteinase-2, and tumor necrosis factor-α by enzyme-linked immunosorbent assay method. Matrix metalloproteinase-2 and MMP-9 activities in serum and vitreous samples were evaluated by gelatin zymography method. Vitreous samples from 16 patients with macular hole undergoing vitrectomy were used as controls.
Among the 2 gelatinase examined in vitreous and serum samples, only level and activity of MMP-9 were significantly higher in serum (P = 0.0001) and vitreous (P = 0.0002) samples of patients with ED than those of control subjects. Simultaneously, a positive correlation was found between intraocular tumor necrosis factor-α and MMP-9 concentration (Spearman correlation coefficient, r = 0.7040, P = 0.0023) in patients with ED.
Increase in MMP-9 activity and its concentration in serum and vitreous of patients with ED compared with that of control subjects and correlation between intraocular levels of MMP-9 and tumor necrosis factor-α in patients with ED seem to provide a plausible explanation for inflammation-mediated angiogenesis during the development of this condition.
[Show abstract][Hide abstract] ABSTRACT: 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.
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).
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.
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.