Endothelin-1 and nitric oxide levels in patients with glaucoma.

Aims: To investigate the levels of endothelin-1 (ET-1) and nitric oxide (NO) in the aqueous humor and plasma of human eyes with different types of glaucoma: primary open-angle glaucoma (POAG) and chronic closed-angle glaucoma (CCAG).

Methods: Patients were classified into 3 groups: group I comprised 35 patients with POAG, group II comprised 25 patients with CCAG, and 30 patients with senile cataract (group III) were used as a control group. Aqueous humor and corresponding plasma were analyzed for ET-1 and NO concentrations by enzyme-linked immunosorbent assay. A Bonferroni correction for multiple comparisons was performed.

Results: There was no significant difference in plasma levels of either ET-1 or NO metabolites between the groups studied. ET-1 and NO were significantly elevated in the aqueous humor of patients with CCAG and POAG compared to the corresponding value in patients with cataract (p < 0.001). ET-1 and NO concentrations in the aqueous humor were more marked in CCAG than in POAG. NO levels were correlated with ET-1 in the aqueous humor of patients with glaucoma (p < 0.001).

Conclusions: Increased concentrations of ET-1 and NO in aqueous humor may be useful with POAG and CCAG. In addition, ET-1 and NO may have useful metabolite levels in the aqueous humor of POAG and CCAG patients as a result of glaucoma damage and may not be a cause of it.