Anatomic and functional characteristics of the rat ileal pouch

Background: The definitive operation for chronic ulcerative colitis (UC) and familial adenomatous polyposis is total proctocolectomy with ileal pouch-anal anastomosis (IPAA). Mild inflammation (pouchitis) is omnipresent in pouches and becomes severe in 50% of UC patients with IPAA. The etiology of pouchitis is likely due to combined genetic, microbial, and immunologic factors. Epithelial cell exposure to surgical trauma and/or to changes in intestinal bacterial composition may account for the inflammatory infiltrate. Progress in understanding pouchitis is restricted by the lack of suitable animal models. Methods: An ileal pouch-rectal anastomosis [IPRA] in rats was developed to reproduce a model of human IPAA and clinical, gross and histologic criteria were determined. Results: Many shared features with human ileal pouch were observed. Conclusion: IPRA is an important in vivo model to study mechanisms of repair, defense and immunity that may contribute to pouchitis.