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DOP34 Transplantation of human intestine into the mouse: A novel platform for study of inflammatory enterocutaneous fistulas

R.S. Bruckner1, E. Nissim-Eliraz2, N. Marsiano2, E. Nir2, H. Shemesh2, M. Leutenegger1, C. Gottier1, S. Lang1, M.R. Spalinger1, S. Leibl3, G. Rogler1,4, S. Yagel5, M. Scharl1,4, N.Y. Shpigel2

1Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland, 2Department of Basic Sciences, Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Rehovot, Israel, 3Department of Pathology and Molecular Pathology, University Hospital Zurich, Zurich, Switzerland, 4Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland, 5Department of Obstetrics and Gynecology, Hadassah University Hospital, Jerusalem, Israel

Background

In Crohn’s disease patients, enteric and perianal fistulas represent a severe and medically challenging comorbidity that affects a broad number of patients. Enteric fistulas do not develop in animal models of colitis what prevents in vivo experiments so far. Based on our preliminary data, we proposed transplantation of the human foetal gut into mice as a novel platform for studying inflammatory enterocutaneous fistulas.

Methods

Human foetal gut segments were transplanted subcutaneously into mature SCID mice, where they grew and fully developed over the course of several months. We first analysed the resident immune cells and inflammatory response elicited by systemic lipopolysaccharide in normal, fully developed human gut xenografts. Thereafter, we used immunostaining to analyse fully developed xenografts that spontaneously developed entero-cutaneous fistulas.

Results

We found a broad number of resident human innate and adaptive immune cells in gut xenografts during steady-state and inflammation. The expression of human IL-8, IL-1β, IL-6, TNF-α, A20, and IkBα was significantly elevated in response to LPS, with no change in IL-10 gene expression. Approximately 17% [19/110] of fully developed subcutaneous human gut xenografts spontaneously developed enterocutaneous fistulas, revealing striking histopathological similarities with CD fistula specimens. Immunohistochemical analyses of fistulating xenografts revealed transmural lymphocytic enteritis associated with a massive expansion of resident human CD4+ lymphocytes and their migration into the intraepithelial compartment. Regionally, mucosal epithelial cells assumed spindle-shaped mesenchymal morphology and formed fistulous tracts towards chronic non-healing wounds in the host mouse skin overlying the transplants.

Conclusion

Conclusions:

Inflammation and fistulas developed in human gut xenografts lacking IL-10 gene response. This novel model system will enable systematic studies of the inflamed and fistulating human gut in live animals.

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