Purpose: To measure the serum levels of the oxidative stress markers superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione peroxidase (GPx) and compare them before and after zinc supplementation in patients with early age-related macular degeneration (AMD). Methods: We measured serum zinc levels in 65 patients with early AMD. Of these, 29 patients with macular drusen and a serum zinc level <80 μg/dL received oral zinc acetate dihydrate (50 mg/day). Serum trace metal levels (zinc and copper) and oxidative stress marker levels (SOD, MDA, and GPx) were measured at baseline and 12 weeks after the treatment. The macular drusen areas and best-corrected visual acuity were evaluated in 24 participants who attended the 3-month follow-up. Results: MDA level was significantly decreased from baseline to 12 weeks after zinc administration (170.5 ± 100.9 vs. 148.3 ± 57.9 pmol/mL, P = 0.03), while SOD was significantly increased from baseline to 12 weeks after zinc intake (4.2 ± 0.9 vs. 4.6 ± 0.9 U/mL, P = 0.03). The serum zinc level was significantly correlated with the MDA level (P = 0.03, ρ = -0.26). The area of soft drusen was significantly decreased after zinc treatment (1,936,654.9 ± 1,348,267.6 vs. 966,883.9 ± 719,938.1 μmm2, P = 0.04). Conclusions: The levels of oxidative stress markers MDA and SOD decreased and increased, respectively, after oral zinc administration to 24 patients with AMD. The therapeutic effect of zinc treatment on drusen area might differ depending on the drusen phenotype in early AMD.
Keywords: age-related macular degeneration; glutathione peroxidase; macular drusen; malondialdehyde; oxidative stress marker; superoxide dismutase; zinc.