Vascular endothelial function and oxidative stress mechanisms in patients with Behcet's syndrome

OBJECTIVES We sought to test the hypothesis that vascular endothelial funct ion is impaired in Behcet's syndrome and reflects increased levels of oxida tive stress. BACKGROUND Behcet's syndrome is a multisystem inflammatory disorder commonl y complicated by vascular thrombosis and arterial aneurysm formation. The p recise mechanisms underlying vascular disease in Behcet's syndrome are not known. METHODS We studied 19 patients with Behcet's syndrome (18 to 50 years old, 9 men) and 21 healthy volunteers (18 to 50 years old, 10 men). Brachial art ery flow-mediated dilation (endothelium-dependent), and nitroglycerin (NTG) -induced dilation (endothelium-independent) were measured. To investigate o xidative stress mechanisms, vascular studies were repeated 1 h alter admini stration of vitamin C (1 g, intravenous) in 12 patients and 12 control subj ects. RESULTS Flow-mediated dilation was reduced in patients with Behcet's syndro me as compared with control subjects (0.7 +/- 0.9% vs. 5.7 +/- 0.9%, p = 0. 001). In contrast, there were no significant differences in the brachial ar tery diameter (4.2 +/- 0.2 vs. 4.0 +/- 0.2 mm, p = 0.47) or NTG-induced dil ation (19.7 +/- 1.9% vs. 19.7 +/- 1.2%, p = 0.98). In regression analysis, Behcet's syndrome was associated with impaired flow-mediated dilation indep endent of age, gender, brachial artery diameter, blood pressure, cholestero l and glucose. Vitamin C increased flow-mediated dilation in Behcet's syndr ome (0.2 +/- 0.7% to 3.5 +/- 1.0%, p = 0.002), but not in control subjects (4.3 +/- 0.6% to 4.7 +/- 0.4%, p = 0.51). In both groups, NTG-induced dilat ion and brachial artery diameter were unchanged after vitamin C treatment. CONCLUSION Vascular endothelial function is impaired in Behcet's syndrome a nd can be rapidly improved by vitamin C treatment. Our results support a ro le for oxidative stress in the pathophysiology of Behcet's syndrome and pro vide a rationale for therapeutic studies aimed at reducing vascular complic ations in this disorder.