Nitric oxide, lipid peroxidation and antioxidant defence system in patients with active or inactive Behçet's disease.

One of the prominent features of Behçet's disease (BD) is vasculitis and thrombosis as a result of endothelial dysfunction. Nitric oxide (NO) is responsible for endothelial vasorelaxation and inhibition of platelet adhesion. To assess serum total NO, erythrocyte superoxide dismutase (SOD), whole blood glutathione peroxidase (GSH-Px), plasma total antioxidant status (TAS) and plasma malondialdehyde (MDA) in patients with BD and to correlate their levels with disease activity. The study group consisted of 49 patients with BD and 26 healthy control subjects. None of the subjects was given a standardized diet. Patients with any systemic disease were excluded. Patients with BD were randomized to two groups according to their disease activity (active/inactive, 26/23). We measured serum total NO levels using the enzyme-linked immunosorbent assay method, and SOD, GSH-Px, TAS and MDA levels by spectrophotometric methods. In patients with active disease (n = 26), serum total NO levels were found to be significantly decreased when compared with the inactive (n = 23) and control (n = 26) groups. Levels were also significantly lower in patients with inactive disease and in total BD patients (n = 49) than in the controls. GSH-Px activities and TAS levels were significantly lower in total BD patients than those in the controls. Patients with active disease and total BD patients exhibited markedly higher MDA levels than the control subjects. MDA levels in the patients with active disease were also found to be elevated compared with the patients with inactive disease. We conclude that changes in parameters associated with oxidative stress such as NO-related processes, activities of antioxidant enzymes in the bloodstream and erythrocytes and total plasma antioxidant capacity are involved in the aetiopathogenesis of the vasculitis seen in BD.