We developed a mouse model of ileo-cecal resection (ICR) and used new and traditional approaches to define cellular mechanisms mediating adaptive intestinal growth to compensate for the intestinal loss. These mechanisms include a brief period of expansion of intestinal stem cells (ISC) immediately after ICR, followed by marked increases in crypt fission, and crypt number which mediate increases in mucosal surface area. Recent reports suggest that there may be two populations of ISC: a slowly cycling quiescent-ISC pool (q-ISC) located above Paneth cells (Upper Stem cell Zone, USZ) and a more rapidly cycling active-ISC pool (a-ISC) of crypt base columnar cells (CBC) marked by the expression of Lgr5. A complete understanding of the adaptive response will require analysis of these putative ISC sub-populations. Our preliminary studies demonstrate increased intestinal IGF-I expression during the period of ISC expansion after ICR. Glucagon-like peptide-2 (GLP-2) augmented the observed ISC expansion and local IGF-I expression, but only if given immediately following resection. In the clinical setting many patients are unable to tolerate enteral nutrition (EN) after massive intestinal loss, and require total parenteral nutrition (TPN). The increased incidence of chronic short bowel syndrome (SBS) in these patients suggests that TPN-feeding may attenuate the normal adaptive ISC expansion. The current proposal examines 3 hypotheses;1. Following ICR, q- ISC and a-ISC show distinct kinetics, as recruitment of q-ISC will precede expansion of a-ISC. 2. IGF-I expression and signaling is required for normal ICR-induced expansion and mediates GLP-2 effects after ICR. Constitutive IGF-I expression will enhance and prolong ISC expansion following ICR. 3. EN drives IGF-I induced ISC expansion following ICR, but in TPN-fed mice GLP-2 will induce local IGF-I and restore ISC expansion following ICR. The following SA will test these hypotheses;SA1. Use the Lgr5-LacZ mouse to define whether ICR induces expansion of Lgr5/LacZ-positive a-ISC and how this relates to the process of crypt fission. Additional studies will validate the temporal expansion of a-ISC and q-ISC following ICR by defining the time course of label retention in the USZ and CBC regions after continuous thymidine analogue labeling. SA2. Study ISC expansion and crypt fission following ICR in transgenic mice with constitutive over-expression of IGF-I or impaired IGF-I signaling. Characterize expansion of ISC in mice with attenuated IGF-IR signaling following ICR + GLP-2. SA3. Randomize the route of providing nutrition to mice following ICR to EN 1 GLP-2 vs. TPN 1 GLP-2. Assess the influence of the route of nutrition and administration of GLP-2 on both intestinal expression of IGF-I and normal ISC expansion following resection.
Surgical loss of the intestine due to injury or disease may result in the inability to absorb enough liquid and food to survive. Fortunately, the remaining intestine is often able to compensate for this intestinal loss over time. When it cannot, people must receive both fluids and nutrition intravenously. Research outlined in this proposal will help us better understand how the cells that continually renew the lining of the intestine every day (intestinal stem cells) increase in number to help compensate following intestinal loss.
| Mezoff, Ethan A; Hawkins, Jennifer A; Ollberding, Nicholas J et al. (2016) The human milk oligosaccharide 2'-fucosyllactose augments the adaptive response to extensive intestinal. Am J Physiol Gastrointest Liver Physiol 310:G427-38 |
| Mahe, Maxime M; Sundaram, Nambirajan; Watson, Carey L et al. (2015) Establishment of human epithelial enteroids and colonoids from whole tissue and biopsy. J Vis Exp : |
| Watson, Carey L; Mahe, Maxime M; Múnera, Jorge et al. (2014) An in vivo model of human small intestine using pluripotent stem cells. Nat Med 20:1310-4 |
| Wang, Fengchao; Scoville, David; He, Xi C et al. (2013) Isolation and characterization of intestinal stem cells based on surface marker combinations and colony-formation assay. Gastroenterology 145:383-95.e1-21 |
| Fuller, Megan K; Faulk, Denver M; Sundaram, Nambirajan et al. (2013) Intestinal stem cells remain viable after prolonged tissue storage. Cell Tissue Res 354:441-50 |
| Stelzner, Matthias; Helmrath, Michael; Dunn, James C Y et al. (2012) A nomenclature for intestinal in vitro cultures. Am J Physiol Gastrointest Liver Physiol 302:G1359-63 |
| Fuller, Megan K; Faulk, Denver M; Sundaram, Nambirajan et al. (2012) Intestinal crypts reproducibly expand in culture. J Surg Res 178:48-54 |
| Van Landeghem, Laurianne; Blue, Randall Eric; Dehmer, Jeffrey J et al. (2012) Localized intestinal radiation and liquid diet enhance survival and permit evaluation of long-term intestinal responses to high dose radiation in mice. PLoS One 7:e51310 |
| Dehmer, Jeffrey J; Garrison, Aaron P; Speck, Karen E et al. (2011) Expansion of intestinal epithelial stem cells during murine development. PLoS One 6:e27070 |
| Speck, Karen E; Garrison, Aaron P; Rigby, Rachael J et al. (2011) Inflammation enhances resection-induced intestinal adaptive growth in IL-10 null mice. J Surg Res 168:62-9 |
Showing the most recent 10 out of 13 publications
