Search

BackgroundNecrotizing enterocolitis (NEC) is a devastating neonatal disease characterized by intestinal necrosis. Hypoxia-inducible factor-1α (HIF-1α) has a critical role in cellular oxygen homeostasis. Here, we hypothesized that prolyl hydroxylase (PHD) inhibition, which stabilizes HIF-1α, protects against NEC by promoting intestinal endothelial cell proliferation and improving intestinal microvascular integrity via vascular endothelial growth factor (VEGF) signaling.MethodsTo assess the role of PHD inhibition in a neonatal mouse NEC model, we administered dimethyloxalylglycine (DMOG) or vehicle to pups before or during the NEC protocol, and determined mortality and incidence of severe intestinal injury. We assessed intestinal VEGF by western blot analysis and quantified endothelial cell and epithelial cell proliferation following immunofluorescence.ResultsDMOG decreased mortality and incidence of severe NEC, increased intestinal VEGF expression, and increased intestinal villus endothelial and epithelial cell proliferation in experimental NEC. Inhibiting VEGFR2 signaling eliminated DMOG’s protective effect on intestinal injury severity, survival, and endothelial cell proliferation while sparing DMOG’s protective effect on intestinal epithelial cell proliferation.ConclusionDMOG upregulates intestinal VEGF, promotes endothelial cell proliferation, and protects against intestinal injury and mortality in experimental NEC in a VEGFR2 dependent manner. DMOG’s protective effect on the neonatal intestinal mucosa may be mediated via VEGFR2 dependent improvement of the intestinal microvasculature.

Necrotizing enterocolitis (NEC) is a major cause of morbidity and death in premature infants. NEC is associated with increased levels of pro-inflammatory cytokines in plasma and tissues that are regulated by the transcription factor nuclear factor-B (NF-B). It remains unknown, however, whether NF-B mediates injury in neonatal NEC. We therefore examined the activation status of NF-B perinatally in the small intestine and in a neonatal rat model of NEC. We found that intestinal NF-B is strongly activated at birth and, in dam-fed newborn rats, is down-regulated within a day. In contrast, NF-B remains strongly activated at both d 1 and d 2 in stressed animals, and this is accompanied by a significant decrease in the levels of the endogenous NF-B inhibitor protein IB and IB at d 2. To determine the importance of elevated NF-B activity in intestinal injury in NEC, we administered the NEMO-binding domain (NBD) peptide that selectively inhibits the critical upstream IB kinase (IKK). NBD but not a control peptide decreased mortality and bowel injury in this model, supporting the hypothesis that bowel injury in NEC results from elevated NF-B activity. Our findings therefore lead us to conclude that selective NF-B inhibition represents a promising therapeutic strategy for NEC.

Necrotizing enterocolitis (NEC) is a major cause of morbidity and death in premature infants. NEC is associated with increased levels of pro-inflammatory cytokines in plasma and tissues that are regulated by the transcription factor nuclear factor-?B (NF-?B). It remains unknown, however, whether NF-?B mediates injury in neonatal NEC. We therefore examined the activation status of NF-?B perinatally in the small intestine and in a neonatal rat model of NEC. We found that intestinal NF-?B is strongly activated at birth and, in dam-fed newborn rats, is down-regulated within a day. In contrast, NF-?B remains strongly activated at both d 1 and d 2 in stressed animals, and this is accompanied by a significant decrease in the levels of the endogenous NF-?B inhibitor protein I?Ba and I?Bß at d 2. To determine the importance of elevated NF-?B activity in intestinal injury in NEC, we administered the NEMO-binding domain (NBD) peptide that selectively inhibits the critical upstream I?B kinase (IKK). NBD but not a control peptide decreased mortality and bowel injury in this model, supporting the hypothesis that bowel injury in NEC results from elevated NF-?B activity. Our findings therefore lead us to conclude that selective NF-?B inhibition represents a promising therapeutic strategy for NEC.