Colorectal tissue engineering : from colonic wall defect to organ replacement ; Ingénierie tissulaire en chirurgie colorectale : du défect pariétal au remplacement d’organe : étude in vitro et in vivo

Tissue engineering is a new tool in colorectal surgery for the prevention and treatment of fistula and rectalsphincter substitution after surgery for resection. This work includes:1) The selection of the matrix component : in vivo, 2 matrices were compared in 16 rabbits: Group A, matrixof decellularized swine intestinal submucosa (SIS, BioDesign ®), or reference matrix; Group B, a three layersmatrix of Chitosan hydrogel, or new matrix. The animals were sacrificed at 4 and 8 weeks. At 8 weeks, earlierepithelial regeneration, better control of the inflammatory response with a lower fibrosis report and obtainingof some islets of smooth muscle cells are obtained in the B group.2) The conception of an optimal delivering cells system: in vitro, fibrin and Chitosan were combined accordingto different formulations for Select a composite gel fibrin-Chitosan, characterized by mechanical tests, viabilityand cellular proliferation and the study of its ultrastructure.3) Their combination: vivo, in lieu of a colonic wall defect, we compared, in 20 pigs, acellular Chtiosan matrixto Chitosan matrix cellularized by autologous stromal vascular fraction isolated and contained in the gelcomposite Chitosan-fibrin. At 8 weeks, a full mucosal recovery was observed in the 2 groups with recovery adintegrum of the colonic walls, including smooth muscle cells confirmed by immunohistochemistery. Thefiborsis ratio was significantly lower in the cellularized group (15% vs. 50%, p = 0, 01). Finally, a cellularizedmatrix of circumferential Chitosan has successfully implanted to replace a colonic defect of 2 cm in length in3 pigs success. With end points such as technical feasibility, matrix behavior and quality of tissueregeneration, Chitosan has a major interest for the Colorectal tissue regeneration. ; L’ingénierie tissulaire représente un nouvel outil en chirurgie colorectale pour la prévention et le traitementdes fistules et pour la substitution sphinctérienne et rectale après chirurgie d’exérèse. Ce travail comprend :1) La sélection de la ...