The neonatal intestinal vasculature: contributing factors to necrotizing enterocolitis.

Based on the demonstration of coagulation necrosis, it is clear that intestinal ischemia plays a role in the pathogenesis of necrotizing enterocolitis (NEC). Intestinal vascular resistance is determined by a dynamic balance between vasoconstrictive and vasodilatory inputs. In the newborn, this balance heavily favors vasodilation secondary to the copious production of endothelium-derived nitric oxide (NO), a circumstance which serves to ensure adequate blood flow and thus oxygen delivery to the rapidly growing intestine. Endothelial cell injury could shift this balance in favor of endothelin (ET)-1-mediated vasoconstriction, leading to intestinal ischemia and tissue injury. Evidence obtained from animal models and from human tissue collected from infants with NEC implicates NO and ET-1 dysregulation in the pathogenesis of NEC. Strategies focused on maintaining the delicate balance favoring vasodilation in the newborn intestinal circulation may prove to be useful in the prevention and treatment of NEC.