Mucosal characteristics of pelvic ileal pouches.

Abstract

This study aimed to investigate the degree of colonic metaplasia in ileo -anal pouches. Biopsy specimens from 25 patients with functioning pouches, eight of whom had pouchitis, were studied using routine histology, mucosal morphometry, mucin histochemistry, and immunoperoxidase staining with monoclonal antibodies directed towards a 4OkD colonic protein and a small bowel specific disaccharidase-sucrase isomaltase. Thirteen patients (including all eight with pouchitis) had subtotal or total vilious atrophy and crypt hyperplasia. In this group, nine had colorectal type sulphomucin and the 40kD colonic protein was detected in two. These changes were not observed in patients with less severe vilious abnormalities. Sucrase-isomaltase activity was, however, present in all 25 pouch specimens. We conclude that although some ileal pouches acquire certain colonic characteristics, complete colonic metaplasia does not occur.

Restorative Proctocolectomy with Ileo-anal Reservoir, a Histopathological, Histochemical, and Electron Microscopic Study

“…These findings have led to the hypothesis that the pouch mucosa undergoes colonic metaplasia as an adaptive change but it may become vulnerable to immune damage or polyp formation, which eventually affects colonic and not ileal mucosa in the susceptible population [5,6]. Many studies until now state that the great majority of functioning ileal reservoirs develop chronic inflammation and villous abnormality regardless of the initial indication for pouch surgery [1,5] as also found in our study (Fig 1 refers). It is important that these common-place pathological changes in the pouch are not equated with a diagnosis of pouchitis, which should be restricted to a clinical syndrome with specific clinical, endoscopic and histopathological features (Table 2), occurring in 6-20% of pouch patients and representing a relapsing chronic inflammatory bowel disease of the pouch [8].…”

“…This adaptation occurs in the form of villous atrophy-as seen in all 8 of our cases and an increase in the goblet cells as seen in 6 of our cases. Some studies have related the degree of villous atrophy to pouchitis [1] but we find no such co-relation and none of our cases had pouchitis according to the laid down criteria.…”

“…Normal colonic biopsy specimens were taken from Introduction R estorative proctocolectomy with ileal pouch -anal anastomosis is now an established alternative to proctocolectomy with an end ileostomy in the surgical management of Ulcerative Colitis and Familial Adenomatous Polyposis. It has also been used in other diseases limited to the colon such as Hirschprung's disease and idiopathic constipation [1]. The operation consisting of total abdominal colectomy, distal rectal mucosectomy and endorectal ileo-anal anastomosis removes the mucosa of the entire colon and rectum, preserves both the transanal route of defaecation and anorectal continence and eliminates the need for a permanent spout ileostomy.…”

“…A study by HJ de Sliva et al [1] reported 8 cases of pouchitis in a sample size of 25 (32%). The adaptive changes of the pouch have been termed colonic phenotypic change / colonisation on account of morphological and histochemical resemblance to colonic mucosa [8].…”

CD10 immunohistochemistry stains enteric mucosa, but negative staining is unreliable in the setting of active enteritis

“…Furthermore, the ileal pouch mucosa undergoes a variety of histological and functional changes and is subject to a nonspecific inflammatory reaction known as 'pouchitis', an idiopathic phenomenon that can lead to pain, diarrhea, and bleeding when severe. [9][10][11] Finally, the ileal mucosa can potentially be changed by the altered physiology ensuing from its new function as a fecal reservoir. 12,13 CD10 is a membrane-associated neutral peptidase, also known as neprilysin, enkephalinase, common acute lymphoblastic leukemia antigen, and neutral endopeptidase.…”