Vitreous albumin redox state in open-angle glaucoma patients and controls: a pilot study

Purpose Numerous studies suggest that reactive oxygen species play a crucial role in the development of glaucoma. Since glaucoma patients exhibit posterior vitreous detachment earlier than controls, it has been suggested that reactive oxygen species—increased in glaucoma—also affect the vitreous. In the present study we evaluated the influence of open-angle glaucoma oxidative stress on the redox state of vitreous albumin. Methods Albumin redox states of the vitreous and plasma were evaluated in 22 subjects—11 open-angle glaucoma patients and 11 controls—matched for age, gender, and vitreous state. According to the redox state of cysteine-34, albumin can be separated into: human mercaptalbumin (the thiol form), human nonmercaptalbumin1 (a reversible modification due to mild oxidation), and human nonmercaptalbumin2 (an irreversible modification due to severe oxidation). Results Albumin of both, the open-angle glaucoma group and the control group, was more oxidized in the vitreous compared to plasma. Furthermore, significantly higher human nonmercaptalbumin1 fractions were found in the vitreous of open-angle glaucoma patients compared to controls. No significant differences were found in the plasma albumin fractions between the groups. Conclusion Our results support the hypothesis that oxidative stress plays a crucial role in open-angle glaucoma and that reactive oxygen species in glaucomatous eyes may also affect the vitreous.