N. A. Drucker1, A. R. Jensen1, M. J. Ferkowicz1, T. A. Markel1 1Indiana University School Of Medicine,Pediatric Surgery,Indianapolis, IN, USA
Introduction: Intestinal ischemia in adults and necrotizing enterocolitis (NEC) in premature infants are both devastating intestinal conditions with poor outcomes. GYY4137 is a long-acting hydrogen sulfide (H2S) donor, which may be protective against intestinal injury in these conditions. We hypothesized that administration of GYY4137 would improve mesenteric perfusion, reduce intestinal injury, and reduce the inflammatory response in intestinal I/R injury and NEC, and that these benefits would be mediated through endothelial nitric oxide-dependent pathways.
Methods: Adult male C57Bl/6 wild type (WT) and eNOS knockout (eNOSKO) mice underwent superior mesenteric artery occlusion for 60 minutes. Prior to abdominal closure, 50mg/kg GYY4137 or PBS vehicle was administered intraperitoneally. In separate groups, NEC was induced in WT and eNOSKO pups via maternal separation, formula feeding, enteral lipopolysaccharide, and intermittent hypoxic and hypothermic stress. Pups received daily intraperitoneal injections of 50mg/kg GYY4137 in 10µL vehicle. Laser Doppler Imaging was used to assess mesenteric perfusion in the adult animals at baseline and 24 hours post-ischemia. Pups were assessed at baseline and P9. After euthanasia, the terminal ileum of each animal was fixed, paraffin embedded, sectioned, and stained with H&E. Sections were blindly graded using published injury scores. Intestinal tissue was homogenized and cytokines measured by ELISA. Data were compared using Mann-Whitney, and p-values <0.05 were significant.
Results: After I/R injury (A) and NEC (B), GYY4137 improved perfusion in WT mice compared to vehicle, but this effect was lost in the eNOSKO animals. Histologic injury followed a similar pattern with reduced intestinal injury in WT mice treated with GYY4137, and no significant improvement in the eNOSKO group. Cytokine expression after GYY4137 administration was altered by the ablation of eNOS in both I/R injury (C) and NEC (D). Significant differences were noted in IL-6, IP-10, and VEGF in the NEC pups, but only in IP-10 in the adult mice after I/R.
Conclusion: GYY4137, a long-acting donor of H2S, has potential as a therapeutic compound for intestinal ischemia. It improves mesenteric perfusion and intestinal injury after ischemia and NEC, and these benefits appear to be mediated through endothelial nitric oxide dependent pathways.
