Evaluation of nitrosative and oxidative stress in Behçet disease.

Plasma nitrotyrosine and nitrite/nitrate levels as markers of nitrosative stress and plasma malondialdehyde (MDA) and protein carbonyl as markers of oxidative stress were determined in patients with Behcet disease (BD). To evaluate the balance between oxidant and antioxidant systems in these patients, we measured erythrocyte lysate CuZn superoxide dismutase (CuZn SOD) activity, plasma sulfhydryl (SH) values and total antioxidant activity. We also determined levels of plasma C-reactive protein (CRP), a key marker of inflammation, and compared them with those of healthy subjects. We found plasma nitrotyrosine levels of BD patients to be increased, indicating that nitrosative stress may occur in these patients. Plasma MDA and CRP levels in BD patients were found to be significantly higher than those in control group. However, plasma SH levels were decreased. No changes were observed in the other measured parameters of the patient group compared with the controls. These data suggest the possible involvement of nitric oxide (NO) together with reactive oxygen substances (ROS) in the pathogenesis of BD.

Lipid peroxidation and antioxidant defence system in patients with active or inactive Behçet's disease.

To evaluate plasma lipid peroxidation and enzymatic and non-enzymatic antioxidant systems in patients with Behçet's disease, plasma malondialdehyde levels and total antioxidant status, erythrocyte superoxide dismutase and whole blood glutathione peroxidase activities were studied in 15 patients with active disease and in 30 with inactive disease, and compared with 20 age-matched healthy control subjects. Plasma malondialdehyde levels were significantly higher in patients with active Behçet's disease than in patients with inactive disease, who had significantly higher levels than control subjects. The plasma total antioxidant status of both groups of patients was significantly lower than that of controls. Furthermore, whole blood glutathione peroxidase activity was significantly lower in patients with active versus inactive Behçet's disease. There were no significant differences in erythrocyte superoxide dismutase levels between the groups. In conclusion, there is an increase in oxidative stress in Behçet's disease. Despite this stress, the antioxidant system is deficient and inadequate, especially in patients who are in an active phase of the disease.