Plasma Biomarkers of Oxidative Stress and Genetic Variants in Age-Related Macular Degeneration

PURPOSE: To compare plasma levels of oxidative stress biomarkers in patients with age-related macular degeneration (AMD) and controls and to evaluate a potential relationship between biochemical markers of oxidative stress and AMD susceptibility genotypes. DESIGN: Prospective case-control study. METHODS: Plasma levels of oxidative stress biomarkers were determined in 77 AMD patients and 75 controls recruited from a clinical practice. Cysteine, cystine (CySS), glutathione, isoprostane, and isofuran were measured, and participants were genotyped for polymorphisms in the complement factor H (CFH) and age-related maculopathy susceptibility 2 (ARMS2) genes. RESULTS: CySS was elevated in cases compared with controls (P = .013). After adjustment for age, sex, and smoking, this association was not significant. In all participants, CySS levels were associated with the CFH polymorphism rs3753394 (P = .028) as well as an 8-allele CFH haplotype (P = .029) after correction for age, gender, and smoking. None of the other plasma markers was related to AMD status in our cohort. CONCLUSIONS: Our investigation of the gene-environment interaction involved in AMD revealed a relationship between a plasma biomarker of oxidative stress, CySS, and CFH genotype. These data suggest a potential association between inflammatory regulators and redox status in AMD pathogenesis. (Am J Ophthalmol 2012; 153:460-467. (C) 2012 by Elsevier Inc. All rights reserved.)