Altered nitric oxide production in the premature gut may increase susceptibility to intestinal damage in necrotizing enterocolitis

Background/Purpose: Nitric oxide (NO) mediates enteric smooth muscle relaxa tion and mucosal protection. The authors have identified an ontogenically d etermined pattern of enteric NO neural maturation that may render the dista l gut of premature piglets susceptible to injury. Methods: NO synthase (cNOS and iNOS) activities were measured in the develo ping piglet gut wall and compared with gut from an intraluminal model of ne crotizing enterocolitis (NEC) at different times. Results: in premature animals, iNOS activity was significantly higher 3 hou rs after NEC induction compared with similarly treated 8-day-old piglets. i NOS levels continued to rise 6 hours after NEC induction in prematures. Pre mature animals (labor induced by prostaglandins) failed to show such a rise in iNOS. In 3 day olds, iNOS levels increased significantly 16 hours after injury compared with the 3-hour group. Conclusions: iNOS production increases in premature piglets with NEC compar ed with full-term NEC animals and continues to rise in the presence of inte stinal damage regardless of developmental status. Maternal administration o f prostaglandins attenuates this rise in iNOS activity. Elevated NO product ion in premature gut may contribute to increased susceptibility to damage i n NEC. J Pediatr Surg 36:700-705. Copyright (C) 2001 by W.B. Saunders Compa ny.