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.
Prospective case-control study
Plasma levels of oxidative stress biomarkers were determined in 77 AMD patients and 75 controls recruited from a clinical practice. Cysteine (Cys), cystine (CySS), glutathione (GSH), isoprostane (IsoP), and isofuran (IsoF) were measured, and participants were genotyped for polymorphisms in the complement factor H (CFH) and age-related maculopathy susceptibility 2 (ARMS2) genes.
CySS was elevated in cases compared to controls (p = 0.013). After adjustment for age, gender, and smoking, this association was not significant. In all participants, CySS levels were associated with the CFH polymorphism rs3753394 (p = 0.028) as well as an eight-allele CFH haplotype (p = 0.029) after correction for age, gender, and smoking. None of the other plasma markers was related to AMD status in our cohort.
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.