Impaired contractile response of mesenteric arteries in Crohn's disease

Background: Crohn's disease is associated with vascular injury and dysregulation of the intestinal immune system which together can provide disturbance of mesenteric circulation functional properties. Aim: To evaluate the vascular reactivity of mesenteric arteries from patients 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-methyl-ester (L-NAME) was used to test the presence of inducible NO synthase. Endothelium dependent and independent relaxation was assessed using acetylcholine, bradykinin, calcium lonophore A23187 and sodium nitroprusside. Results: The contractile response to phenylephrine was significantly decreased in arteries without endothelium from patients with Crohn's disease. Exposure 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 caused by phenylephrine in Crohn's disease. The restored mesenteric artery tone by a specific NO synthase inhibitor suggests that an increased production for NO in vascular smooth muscle might be responsible of this altered vascular reactivity.