Comparison of serum thiol-disulphide homeostasis and total antioxidant-oxidant levels between exudative age-related macular degeneration patients and healthy subjects.

PURPOSE: The purpose of the study was to calculate serum total oxidant status (TOS), total antioxidant status (TAS), and dynamic thiol-disulphide (T-D) homeostasis in patients with age-related macular degeneration (AMD), and compare the results with healthy individuals.
METHODS: Thirty-three exudative AMD patients and 33 healthy controls were included in this case-control study. Participants' serum TAS and TOS levels were measured. In addition, total thiol (TT), native thiol (NT), and disulphide (DS) concentrations were assessed using a novel automated method of measurement.
RESULTS: In comparison with the control group, serum TAS, TT, and NT levels were found to be significantly lower (p < 0.0001, p = 0.004, p = 0.003, respectively) and TOS levels were detected higher (p = 0.032) in AMD patients. Serum DS levels were elevated in the AMD patient group, but the difference was not statistically significant (p = 0.219). DS/TT and DS/NT ratios were significantly higher (p = 0.012, p = 0.013, respectively) in AMD patients. A positive correlation was found between TT and NT (p < 0.0001) in AMD group.
CONCLUSIONS: Serum TOS levels are higher, TAS levels are lower, and the T-D balance is shifted to the DS bond side in AMD patients. These results suggest that increased oxidative stress and decreased antioxidant levels may play a role in AMD progression. Further studies are needed to confirm the pathophysiologic role of T-D homeostasis in AMD.