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Synergistic Effects of HB-EGF and Mesenchymal Stem Cells In a Murine Model of Intestinal Ischemia/Reperfusion Injury

Saturday, October 20, 2012: 9:30 AM
Versailles Ballroom (Hilton Riverside)
Daniel J. Watkins, MD, Hong-Yi Zhang, MD, Amanda Darbyshire, BS and Gail E. Besner, MD, Department of Pediatric Surgery and Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH

Purpose

Mesenchymal stem cells (MSC) are pluripotent, self-renewing progenitor cells with therapeutic efficacy in different animal models of ischemic end-organ injury. MSC can be isolated from multiple sources including the bone marrow and amniotic fluid. Heparin-binding EGF-like growth factor (HB-EGF) has potent intestinal cytoprotective effects in many different animal models of intestinal injury, including intestinal ischemia/reperfusion (I/R) injury. We have previously shown that HB-EGF promotes MSC proliferation and migration, and decreases MSC apoptosis in vitro, with more potent effects on amniotic fluid-derived (AF-MSC) compared to bone marrow-derived (BM-MSC) cells. The hypotheses of the current study are that HB-EGF administration combined with MSC transplantation in a mouse model of intestinal I/R injury leads to decreased histologic injury and improved gut barrier function compared to either therapy alone, and that HB-EGF may promote increased MSC intestinal engraftment.

Methods

MSC were isolated from bone marrow (BM-MSC) and amniotic fluid (AF-MSC) of adult pan-EGFP mice. Pluripotency was confirmed by induced differentiation into adipocyte and osteocyte lineages. Mice were subjected to terminal ileal ischemia for 60 minutes after which they received either: 1) no therapy; 2) HB-EGF intraluminally (IL); 3) BM-MSC intraperitoneally (IP); 4) HB-EGF IL combined with BM-MSC IP; 5) AF-MSC IP; or 6) HB-EGF IL combined with AF-MSC IP. 24 hours after injury, the intestines were harvested, histologic injury scores were graded, MSC engraftment was quantified, and intestinal permeability was determined using the everted gut sac method.

Results

Histologic injury was significantly decreased for all treatment modalities (HB-EGF 1.3±0.5 p<0.01, BM-MSC 1.9±1.1 p<0.01, BM-MSC+HB-EGF 1.6±0.9 p<0.01, AF-MSC 2±0.8 p<0.01 and AF-MSC+HB-EGF 1.5±1.2 p<0.01) compared to I/R injury alone (3.4±0.7). In the absence of HB-EGF administration, both BM-MSC and AF-MSC preferentially engrafted into injured terminal ileum compared to uninjured jejunum (1.3±0.6 vs. 0.3±0.3 BM-MSC/villus, p<0.01 and 0.9±0.5 vs. 0.1±0.1 AF-MSC/villus, p<0.01). Similar preferential engraftment of MSC into injured ileum was seen in the presence of HB-EGF administration. However, there was significantly increased terminal ileal engraftment when AF-MSC were administered in conjunction with HB-EGF compared to administration of AF-MSC alone (1.6±0.5 vs.0.9±0.5 AF-MSC/villus, p<0.05). Intestinal permeability was significantly improved in all treatment groups compared to injury alone (92.9±30.9), with the greatest improvement seen with administration of AF-MSC and HB-EGF together (12.6±7.6, p<0.01). Intestinal permeability in this combined therapy group was significantly improved compared with administration of either HB-EGF alone (30.4±17.8, p<0.05) or AF-MSC alone (42.2±15.2, p<0.01).

Conclusions

These data demonstrate that HB-EGF and MSC protect the intestines from I/R injury, with the combination of AF-MSC and HB-EGF administration having the greatest beneficial effect on gut barrier function. Administration of HB-EGF in combination with AF-MSC leads to increased AF-MSC engraftment into injured intestine. Combination therapy with HB-EGF and MSC transplantation may represent a novel therapeutic strategy for I/R-associated intestinal injury in the future.