Glaucoma and oxidative stress.: Determination of malondialdehyde -: a product of lipid peroxidation

Background. Primary open-angle glaucoma (POAG) is a multifactorial disease, in which aging, race, genetic disposition, vascular status, probably inflammation, and maybe oxidative stress may play a specific role. We wanted to know if by using a common test for a specific oxidative stress product differences would be found in the aqueous humor and serum of patients with POAG, cataract without pseudoexfoliation, cataract with pseudoexfoliation, and volunteers without ocular disease. Patients and methods. We examined the aqueous humor of 33 patients with POAG, 111 patients with cataract without pseudoexfoliation, 39 patients with cataract and pseudoexfoliation syndrome and the serum of all three groups plus of 43 volunteers without ocular disease. Malondialdehyde as an oxidative stress product of peroxidation of lipids was proven by thiobarbituric acid-reacting substances (TBARS). Results. The amount of TBARS is given in mu mol/l: (1) in the serum of the group with cataract 1.176, with cataract and pseudoexfoliation 1.019, with POAG 0.992, and with healthy eyes 0.983; (2) in the aqueous humor of the group with cataract 0.279, with cataract and pseudoexfoliation 0.274, and with POAG 0.298. There were no statistically significant differences of TBARS (p < 0.05) in either the aqueous humor or in the serum of patients with POAG in comparison to those patients without POAG. However, there was a significantly positive correlation between the values in the serum and the aqueous humor. Conclusion. For the first time malondialdehyde as a product of lipid peroxidation was determined in the aqueous humor of glaucomatous eyes. With the TBARS method used in our study, it was not possible to detect statistically significant differences of the lipid peroxidation product malondialdehyde between patients with or without POAG. It has to be taken into account that the cataract of the patients in the control group might be a disease per se caused by at least a certain amount of oxidative stress and that these subjects might therefore not be ideal as a control group.