The redox state of human serum albumin in eye diseases with and without complications

Abstract

To investigate the redox state of human serum albumin concerning cysteine-34 as a possible systemic redox marker in patients with different eye diseases with and without complications and with consideration of possible effects of age. Cataract (CAT), glaucoma, age-related macular degeneration (AMD), diabetes mellitus (DM), diabetic retinopathy and hypertension were the pathologies investigated. Albumin redox state concerning cysteine-34 was measured by high-performance liquid chromatography with fluorescence detection. The separation gives three fractions: the fully reduced form containing a thiol group, the disulphide form and a higher oxidized form. Statistical analysis was done by Student's t-test, analysis of variance and stepwise regression analysis. Albumin as a systemic marker for oxidative stress was shifted to a more oxidized state by DM. An even stronger shift to the oxidized form was observed in patients with proliferative diabetic retinopathy. Notably, these effects were independent from age. In contrast, CAT and AMD had no influence on serum albumin redox state. Serum albumin is not shifted to more oxidized forms by localized oxidative stress, but it is in systemic diseases like DM.