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.