Impaired contractile response of mesenteric arteries in Crohn's disease

Background: Crohn's disease is associated with vascular injury and dysregul ation of the intestinal immune system which together can provide disturbanc e of mesenteric circulation functional properties. Aim: To evaluate the vascular reactivity of mesenteric arteries from patien ts with Crohn's disease. Methods: Phenylephrine-induced contractions were assessed from 10 patients with Crohn's disease and 8 control organ donors. N-G-nitro-L-arginine-methy l-ester (L-NAME) was used to test the presence of inducible NO synthase. En dothelium dependent and independent relaxation was assessed using acetylcho line, bradykinin, calcium ionophore A23187 and sodium nitroprusside. Results: The contractile response to phenylephrine was significantly decrea sed in arteries without endothelium from patients with Crohn's disease. Exp osure to the NO synthase inhibitor L-NAME restored the contractile response to phenylephrine. Relaxation remained unaltered in both groups. Conclusion: These data provide direct evidence for fading of contraction ca used by phenylephrine in Crohn's disease. The restored mesenteric artery to ne by a specific NO synthase inhibitor suggests that an increased productio n for NO in vascular smooth muscle might be responsible of this altered vas cular reactivity.