Regenerative signals for intestinal epithelial organoid units transplantedon biodegradable polymer scaffolds for tissue engineering of small intestine

Background Our laboratory is investigating the tissue engineering of small intestine using intestinal epithelial organoid units seeded onto highly por ous biodegradable polymer tubes. This study investigated methods of stimula tion for optimizing neointestinal regeneration. Methods. Intestinal epithelial organoid units harvested from neonatal Lewis rats were seeded onto porous biodegradable polymer tubes and implanted int o the omentum of adult Lewis rats in the following groups: (1) the control group (group C), implantation alone (n=9); (2) the small bowel resection (S Br) group, after 75% SBr (n=9); (3) the portacaval shunt (PCS) group, after PCS (n=8); and (4) the partial hepatectomy (PH) group, after 75% PH (n=8), Neointestinal cyst size was recorded using ultrasonography. Constructs wer e harvested at 10 weeks and were examined using histology. Morphometric ana lysis of the neomucosa was obtained using a computer image analysis program (NIH Image, version 1.59), Results. Cyst development was noted in all animals. Cyst lengths and diamet ers were significantly larger in the SBr group at 7 and 10 weeks compared w ith the other three groups (P<0.05; analysis of variance [ANOVA], Fisher's protected least significant difference). Histology revealed a well-vascular ized tissue with a neomucosa lining the lumen with invaginations resembling crypt-villus structures, Morphometric analysis demonstrated a significantl y greater villus number, height, area, and mucosal surface in the SBr group compared with the other three groups and a significantly greater crypt num ber and area in the PCS group compared with group C (P<0.05; ANOVA, Fisher' s protected least significant difference). Conclusions. Intestinal epithelial organoid units transplanted on porous bi odegradable polymer tubes can successfully vascularize, survive, and regene rate into complex tissue resembling small intestine. SBr and, to a lesser e xtent, PCS provide significant regenerative stimuli for the morphogenesis a nd differentiation of tissue-engineered small intestine.