Permanently increased mucosal permeability in patients with backwash ileitis after ileoanal pouch for ulcerative colitis.

OBJECTIVE: Backwash ileitis (BI) has not been identified as a risk factor for pouchitis. The aim of this study was to investigate the barrier function of the ileoanal pouch depending on the presence of BI. The incidence of pouchitis in a population of ulcerative colitis patients with BI is also reported.

MATERIAL AND METHODS: Biopsies were taken from 80 patients with ulcerative colitis: a) terminal ileum prior to pouch creation (pre-IAP); b) 16 months after ileostomy closure (intact pouch); and c) during pouchitis. Patients were stratified into the BI group and the non-BI (ØBI) group. Barrier function was determined in Ussing-chambers as epithelial resistance by impedance analysis and as mannitol permeability from (3)H-mannitol fluxes. Na(+)-glucose co-transport was measured as a change in short-circuit current (I(SC)) after addition of glucose. Relative risk of developing pouchitis was calculated by corrected chi(2) test.

RESULTS: In 13/21 (BI/ØBI) pre-IAP patients, 23/37 (BI/ØBI) with an intact pouch, and 35/7 (BI/ØBI) with pouchitis, epithelial resistance in BI/ØBI was 13.5+/-1.6/14.3+/-0.9 Omega.cm(2) for pre-IAP, 12.7+/-1.3/16.8+/-1.2 Omega x cm(2) (p<0.05 BI versus ØBI) for the intact pouch, and 10.1+/-1.1/9.9+/-1.8 Omega x cm(2) for pouchitis (p<0.05 BI versus ØBI with an intact pouch). No differences were found for electrogenic chloride secretion and active Na(+)-glucose co-transport between BI/ØBI in the three groups. In patients with BI, pouchitis was more common (35 versus 7 patients, odds ratio 33.0 (95% CI 8.3-143.9; p<0.0001)).

CONCLUSIONS: Ulcerative colitis patients with BI show impaired barrier function in the further course of the ileoanal pouch. Thus, BI has a long-term impact on epithelial barrier function.