Analysis of the Interleukin-6 (-174) Locus Polymorphism and Serum IL-6 Levels with the Severity of Normal Tension Glaucoma.

PURPOSE: In normal tension glaucoma (NTG), factors other than elevated intraocular pressure are likely to have a role in the pathogenesis of optic neuropathy. Recent studies of glaucoma or retinal ganglion cells (RGCs) reveal that the cytokine interleukin-6 (IL-6) is linked to the pathogenesis of glaucoma and may regulate RGC survival or death. The IL-6 (-174) G allele has also been shown to increase the IL-6 protein. We hypothesized that the IL-6 (-174) polymorphism may be a predisposing genetic factor affecting the severity of glaucoma. The aim of the present study was to evaluate the IL-6 polymorphism and serum IL-6 levels as a potential risk factor related to the severity of NTG. METHODS: A total of 256 subjects with NTG in the Chinese population were enrolled. The patients were genotyped for the IL-6 (-174) C/G polymorphism. Genomic DNA was amplified by a polymerase chain reaction, followed by the enzymatic restriction fragment length polymorphism technique. Serum IL-6 levels were measured by ELISA. Patient age at diagnosis, cup/disc (C/D) ratio, rim area (RA), retinal nerve fiber layer (RNFL) thickness, and visual field (VF) were analyzed. The associations between genotypes of IL-6 (-174) C/G and the clinical parameters were calculated using a logistic regression. RESULTS: The IL-6 (-174) GC genotype in NTG patients was significantly associated with a smaller C/D ratio (p = 0.04), larger RA (p = 0.04), and thicker RNFL (p = 0.05) compared with IL-6 (-174) GG patients. The allele frequency of IL-6 (-174) C was significantly higher in the NTG patients at an early-moderate stage than at an advanced stage according to the C/D ratio (OR 0.55; 95% CI 0.31-0.99). Pattern standard deviation of VF was borderline lower in IL-6 (-174) GC patients (p = 0.06), and serum IL-6 levels were borderline higher in advanced stages than in early-moderate stages (7.66 ± 3.22 vs. 4.46 ± 3.83 pg/mL; p = 0.06). CONCLUSION: The IL-6 (-174) GC genotype is associated with a smaller C/D ratio, larger RA, and thicker RNFL compared with IL-6 (-174) GG in NTG patients. We found that the IL-6 (-174) G/C polymorphism and serum IL-6 levels may be associated with the severity of NTG.

Polymorphism in the TNF-α(-863) locus associated with reduced risk of primary open angle glaucoma.

PURPOSE: Tumor necrosis factor-α (TNF-α), an important proinflammatory cytokine, exerts a variety of physiologic and pathogenic effects that lead to tissue destruction. Recent laboratory evidence indicates that TNF-α have either protective or adverse effects on primary open angle glaucoma (POAG). Inheritance of the TNF-α (-863) C allele has been associated with an elevated risk of Alzheimer disease. The neuronal injuries associated with Alzheimer disease have several similarities with the optic nerve changes often seen with POAG. In this study we investigated the possible association between the TNF-α (-863) polymorphism and the development of POAG. METHODS: A total of 234 patients with POAG were recruited and compared with 230 healthy controls in a Chinese population. Sequence-specific primers with 3' end mismatches were used to identify the presence of specific allelic variants by polymerase chain reaction (PCR) amplification. Patients and controls were genotyped for the A/C polymorphism at position -863 of the TNF-α gene promoter region. RESULTS: The frequency of the TNF-α (-863)A allele (22% versus 30%, respectively; p=0.007) and the carriers of the TNF-α (-863)A allele (37% versus 48%; p=0.017, OR 0.63, 95% CI 0.44-0.92) were lower in POAG patients compared with those in controls. There is a reduced risk of POAG associated with homozygosity for the TNF-α (-863)A allele (AA genotype) compared with that in the control population (AA genotype; 7% versus 11%, respectively, p=0.037; OR 0.5, 95% CI 0.26-0.98). CONCLUSIONS: The TNF-α (-863)A allele polymorphism may be a protective factor in the development of POAG.

Association between Metformin and a Lower Risk of Age-Related Macular Degeneration in Patients with Type 2 Diabetes.

PURPOSE: This population-based, retrospective cohort study was to investigate whether metformin is associated with a lower risk of subsequent age-related macular degeneration (AMD) in patients with type 2 diabetes. METHODS: Using the Taiwan National Health Insurance Research Database from 2001 to 2013, 68205 subjects with type 2 diabetes were enrolled in the study cohort. Among them, 45524 were metformin users and 22681 were nonusers. The metformin and nonmetformin groups were followed until the end of 2013. Cox regression analyses were used to estimate hazard ratios (HRs) for AMD development associated with metformin use. Confounders included for adjustment were age, sex, and comorbidities (hypertension, hyperlipidemia, coronary artery disease, obesity, diabetic retinopathy, chronic kidney disease, and insulin treatment). Furthermore, propensity score (PS) matching method was used to choose the matched sample, and PS-adjusted Cox regression was performed. Finally, how HRs changed according to metformin treatment duration and dose was also evaluated in the metformin group. RESULTS: After adjusting for confounders, the metformin group had a significantly lower risk of AMD (adjusted HR = 0.54; 95% confidence interval [CI], 0.50-0.58). In the PS-matched sample, the significance remained (adjusted HR = 0.57; 95% CI, 0.52-0.63). In the metformin group, the adjusted HRs for the second (1.5-4 years) and third (≥4 years) tertiles of metformin treatment duration were 0.52 and 0.14, respectively, compared with the first tertile (<1.5 years). We also found significant trends of lower HRs (all p-value for trend <0.05) with increasing total and average doses. CONCLUSIONS: Among patients with type 2 diabetes, those who use metformin are at a significantly lower risk of developing AMD relative to individuals who do not use metformin. Also, the trend of a significantly lower AMD risk was found with a higher dose of metformin.

Risk of Ischemic Stroke, Hemorrhagic Stroke, and All-Cause Mortality in Retinal Vein Occlusion: A Nationwide Population-Based Cohort Study.

PURPOSE: To investigate whether the risk of subsequent stroke, ischemic stroke, hemorrhagic stroke, and all-cause mortality is increased among retinal vein occlusion (RVO) patients compared to non-RVO patients. METHODS: From the entire population of the Taiwan National Health Insurance Research Database (NHIRD) from 2001 to 2013, a total of 22919 subjects with RVO were enrolled in the RVO group, and 114595 propensity score (PS)-matched non-RVOs were enrolled in the comparison group. PS matching was based on age, gender, obesity, diabetes, hypertension, hyperlipidemia, coronary artery disease, atrial fibrillation, hyperviscosity syndrome, Charlson comorbidity index, glaucoma, and the use of antithrombotic drugs. A multivariate Cox regression analysis was used to estimate the adjusted hazard ratios (HRs) with a 95% confidence interval (CI) for each of the clinical outcomes, including stroke, ischemic stroke, hemorrhagic stroke, and all-cause mortality. Furthermore, we divided the RVO group into the branch retinal vein occlusion (BRVO) group and the central retinal vein occlusion (CRVO) group and separately compared their subsequent risks of the clinical outcomes with those of the comparison group. RESULTS: After adjusting for PS, the RVO group had a significantly higher risk of stroke (adjusted HR = 1.36; 95% CI: 1.32-1.40), ischemic stroke (adjusted HR = 1.36; 95% CI: 1.32-1.40), and hemorrhagic stroke (adjusted HR = 1.34; 95% CI: 1.24-1.44). However, the all-cause mortality did not exhibit significant differences. Furthermore, both the BRVOs and CRVOs had a significantly higher risk of subsequent stroke, ischemic stroke, and hemorrhagic stroke than did the comparisons, whereas all-cause mortality was similar among the groups. CONCLUSIONS: People with RVO are at a significantly greater risk of developing stroke, ischemic stroke, and hemorrhagic stroke. However, RVO does not significantly increase the risk of all-cause mortality.