Impaired nitric oxide production in patients with primary open-angle glaucoma.

Glaucoma is an optic neuropathy induced by many factors. Vascular dysfunction is involved in the mechanism underlying glaucoma.To determine the involvement of nitric oxide (NO), which is implicated in the regulation of ocular blood flow, in primary open angle glaucoma (POAG). Furthermore, lactate and uric acid (UA) levels were investigated.Concentrations of NO, UA and lactate in plasma and aqueous humor (AH) were measured in 214 Tunisian patients (100 patients with POAG and 114 subjects with cataract as control group). NO metabolites, nitrate and nitrite (NOx) production were determined using the Griess reaction. UA and lactate concentrations were measured using enzymatic- colorimetric methods.NOx concentrations in patients with POAG were significantly lower compared to cataract group in plasma (5.23±1.55 µmol/L vs 18.35±6.87 µmol/L, p=0.01) and AH (20.54±7.41 µmol/L vs 45.25±10.92 µmol/L, p=0.02). Plasma and AH levels of lactate and UA were significantly higher in glaucoma patients than in control subjects.In the present study, decreased NO and increased UA and lactate levels were found in the AH and plasma of POAG patients compared to control subjects. These data suggest a possible involvement of these factors in glaucoma.