Hydrogen Sulfide Donor GYY4137 Acts Through Endothelial Nitric Oxide to Protect Intestine in Murine Models of Necrotizing Enterocolitis and Intestinal Ischemia

Abstract

Background: Necrotizing enterocolitis (NEC) in premature infants is often a devastating surgical condition with poor outcomes. GYY4137 is a long-acting donor of hydrogen sulfide (H 2 S), a gasotransmitter that is protective against intestinal injury in experimental NEC, likely through protection against injury secondary to ischemia. We hypothesized that administration of GYY4137 would improve mesenteric perfusion, reduce intestinal injury, and reduce inflammatory responses in experimental NEC and ischemia-reperfusion injury, and that these benefits would be mediated through endothelial nitric oxide synthase-dependent pathways. Methods: NEC was induced in C57BL/6 wild type (WT) and endothelial nitric oxide synthase (eNOS) knockout (eNOSKO) pups via maternal separation, formula feeding, enteral lipopolysaccharide, and intermittent hypoxic and hypothermic stress. Pups received daily intraperitoneal injections of 50mg/kg GYY4137 or PBS vehicle. In separate groups, adult male WT and eNOSKO mice underwent superior mesenteric artery occlusion for 60 minutes. Prior to abdominal closure, 50mg/kg GYY4137 or PBS vehicle was administered into the peritoneal cavity. Laser Doppler Imaging was used to assess mesenteric perfusion of pups at baseline and on P9, and the adult mice at baseline and 24 hours post-ischemic insult. 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.

Remote ischemic conditioning counteracts the intestinal damage of necrotizing enterocolitis by improving intestinal microcirculation

“…NO belongs to the subfamily of endogenous gaseous signaling molecules, similar to hydrogen sulfide (H 2 S). Findings by other studies have also supported a role for NO and H 2 S to protect the intestine against the development of NEC by increasing microvascular blood flow via vasodilation 15 , 16 . These findings suggest that promoting sufficient intestinal blood flow in the immature intestine could prevent mucosal damage and improve the outcome of NEC.…”

“…To explore the role of vasodilation and enhanced intestinal perfusion in the protective effects of RIC, we used chemical inhibitors of NO and H 2 S, potent gaseous vasodilators in the developing gastrointestinal tract 16 , 27 , 28 , 39 . We demonstrated that inhibition of synthesis of NO abolished the RIC-mediated improvements in intestinal perfusion and resulted in poor intestinal morphology and increased inflammation.…”

“…We demonstrated that inhibition of synthesis of NO abolished the RIC-mediated improvements in intestinal perfusion and resulted in poor intestinal morphology and increased inflammation. H 2 S is known to improve intestinal perfusion via an eNOS -dependent mechanism 16 , suggesting that intestinal microcirculation is controlled by H 2 S upstream of the NO pathway. Inhibitors of H 2 S synthesizing enzymes CBS and CSE are commonly used to inhibit endogenous H 2 S synthesis, and hence to investigate the biological effects of suppressing H 2 S-mediated vasodilation 40 .…”

The Protective Role of Hydrogen Sulfide Against Obesity-Associated Cellular Stress in Blood Glucose Regulation

“…It should be noted that our route of administration for the H 2 S donor was IP. When injecting the compound, H 2 S will diffuse throughout the body [ 26 ] including the intestinal villi [ 36 ] where L-cells are located. Indeed, IP injections of GYY4137 have been previously shown to impact villus structure [ 36 ] suggesting the compounds ability to reach the intestine.…”

Exogenous hydrogen sulfide alleviates surgery-induced neuroinflammatory cognitive impairment in adult mice by inhibiting NO signaling

“…In addition, H 2 S exerts both pro-and anti-inflammatory effects [24]. The exogenous hydrogen sulfide donor GYY4137 induces the slow release of H 2 S and reduces intestinal inflammation and protects against intestinal ischemia via eNOS-dependent pathways [25].…”