Necrotizing enterocolitis (NEC) is an often catastrophic disease that typically affects premature newborns. Although the exact etiology of NEC is uncertain, the disease is associated with formula feeding, bacterial colonization of the gut, hypoxia, and hypoperfusion. In light of the pathogenesis of NEC, the integrity and function of the intestinal mucosa plays a major defensive role against the initiation of NEC. Various forms of intestinal injury, including NEC, injure the intestinal epithelial cell (IEC) lineages, including the intestinal stem cells (ISCs), thereby disrupting the normal homeostasis needed to maintain gut barrier function. In the current study we examined the effects of HB-EGF administration on enterocytes, goblet cells, neuroendocrine cells and intestinal stem cells in a newborn rat model of experimental NEC. We also examined the cytoprotective effects of heparin-binding EGF-like growth factor (HB-EGF) on intestinal stem cells in in vitro cell cultures and in ex vivo crypt-villous organoid cultures. We found that HB-EGF protects all intestinal epithelial cell lineages, including intestinal stem cells, from injury. We further found that HB-EGF protects isolated intestinal stem cells from hypoxic injury in vitro, and promotes intestinal stem cell activation and survival, and the expansion of crypt transit amplifying cells, in ex vivo crypt-villous organoid cultures. The protective effects of HB-EGF were dependent upon EGF receptor activation, and were mediated via the MEK1/2 and PI3K signaling pathways. These results demonstrate that the intestinal cytoprotective effects of HB-EGF are mediated, at least in part, through its ability to protect intestinal stem cells from injury.

Background Surgical management of long segment tracheal disease is limited by a paucity of donor tissue and poor performance of synthetic materials. A potential solution is the development of a tissue-engineered tracheal graft (TETG), which promises an autologous airway conduit with growth capacity. Methods We created a TETG by vacuum seeding bone marrow-derived mononuclear cells (BM-MNCs) on a polymeric nanofiber scaffold. First, we evaluated the role of scaffold porosity on cell seeding efficiency in vitro. We then determined the effect of cell seeding on graft performance in vivo using an ovine model. Results Seeding efficiency of normal porosity (NP) grafts was significantly increased when compared to high porosity (HP) grafts (NP: 360.3 ± 69.19 ×103 cells/mm2; HP: 133.7 ± 22.73 ×103 cells/mm2; p<0.004). Lambs received unseeded (n=2) or seeded (n=3) NP scaffolds as tracheal interposition grafts for 6 weeks. Three animals were terminated early due to respiratory complications (n=2 unseeded, n=1 seeded). Seeded TETG explants demonstrated wound healing, epithelial migration, and delayed stenosis when compared to their unseeded counterparts. Conclusion Vacuum seeding BM-MNCs on nanofiber scaffolds for immediate implantation as tracheal interposition grafts is a viable approach to generate TETGs, but further preclinical research is warranted before advocating this technology for clinical application.

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Background Acute respiratory distress syndrome continues to be a major source of morbidity and mortality in critically-ill patients. Heparin binding EGF-like growth factor (HB-EGF) is a biologically active protein that acts as an intestinal cytoprotective agent. We have previously demonstrated that HB-EGF protects the intestines from injury in several different animal models of intestinal injury. In the current study, we investigated the ability of HB-EGF to protect the lungs from remote organ injury after intestinal ischemia/reperfusion (I/R). Methods Mice were randomly assigned to one of the following groups: 1) sham-operated; 2) sham + HB-EGF (1200 µg/kg in 0.6 mL administered by intra-luminal injection at the jejuno-ileal junction immediately after identification of the superior mesenteric artery); 3) superior mesenteric artery occlusion for 45 min followed by reperfusion for 6 h (I/R); or 4) I/R+HB-EGF (1200 µg/kg in 0.6 mL) administered 15 min after vascular occlusion. The severity of acute lung injury was determined by histology, morphometric analysis and invasive pulmonary function testing. Animal survival was evaluated using Kaplan-Meier analysis. Results Mice subjected to intestinal I/R injury showed histological and functional evidence of acute lung injury and decreased survival compared to sham-operated animals. Compared to mice treated with HB-EGF (I/R + HB-EGF), the I/R group had more severe acute lung injury, and decreased survival. Conclusion Our results demonstrate that HB-EGF reduces the severity of acute lung injury after intestinal I/R in mice. These data demonstrate that HB-EGF may be a potential novel systemic anti-inflammatory agent for the prevention of the systemic inflammatory response syndrome (SIRS) after intestinal injury.