Increase of 8-Hydroxy-2′-Deoxyguanosine in Aqueous Humor of Patients with Exudative Age-Related Macular Degeneration

Abstract

Oxidative stress has been implicated as a major contributor to age-related macular degeneration (AMD). 8-Hydroxy-2'-deoxyguanosine (8-OHdG) is one of the most abundant oxidative products of DNA damage and represents a noninvasive and sensitive biomarker of oxidative stress. The authors investigated the 8-OHdG levels in aqueous humor of patients with exudative AMD. Twenty-four eyes of 24 patients with active exudative AMD and 31 eyes of 31 age-matched subjects who underwent cataract surgery were enrolled. Aqueous humor samples were collected from all subjects, and the 8-OHdG levels were determined by a commercially available enzyme-linked immunosorbent assay kit. The choroidal neovascularization (CNV) subtype was classified by fluorescein angiography. The macular lesion, including CNV membrane, exudation, and retinal hemorrhage, was measured. The correlation between 8-OHdG level and the clinical features was analyzed. The 8-OHdG level in the aqueous humor of AMD patients was significantly higher than it was in controls (0.581 ± 0.258 ng/mL vs. 0.251 ± 0.116 ng/mL; P < 0.001), after adjusting for age and lens status. There was no difference in the 8-OHdG levels between AMD patients with classic/predominantly classic and occult/minimally classic CNV (0.591 ± 0.262 vs. 0.566 ± 0.266 ng/mL; P = 0.639). The 8-OHdG level in aqueous humor was significantly correlated with the lesion size (ρ = 0.492; P = 0.017). The 8-OHdG level in aqueous humor was higher in patients with exudative AMD, and the level was correlated with the area of macular lesion. This suggests that oxidative stress plays an important role in the disease course of AMD.