Enteral inulin doles not affect epithelial gene expression and cell turnover within the ileoanal pouch - Randomized, placebo-controlled, crossover study

PURPOSE: This study evaluates the effects of enteral inulin on ileoanal pou ch functioning by studying epithelial gene expression, cell turnover, and m ucosal morphology. METHODS: Twenty patients with an ileoanal pouch received 24 g of inulin daily for three weeks, then a four-week wash-out period, an d a placebo for three weeks. In this randomized, double-blind, crossover st udy, biopsy specimens of pouch mucosa were taken after each test period. Mu cosal morphology, inflammation, epithelial proliferation, and cell death we re assessed histologically. Expressions of proapoptotic and antiapoptotic r egulators, intestinal fatty acid-binding protein, and mucin were quantified by Western blotting of enzyme-linked immunosorbent assay. The number of in testinal fatty acid-binding protein expressing cells was histologically ass essed and a high iron diamine/Alcian blue staining was performed to discrim inate between sulfated and nonsulfated acidic mucins. RESULTS: Inulin suppl ementation neither altered mucosal morphology nor influenced inflammation, epithelial cell proliferation, or cell death. The ratio between the proapop totic and antiapoptotic regulators did not change after inulin supplementat ion. The number of intestinal fatty acid-binding protein-producing enterocy tes and the intestinal fatty acid-binding protein expression level increase d after inulin treatment, but did not reach statistical significance. The i ntestinal fatty acid-binding protein expression level correlated with the P ouchitis Disease Activity Index, which was at the brink of significance (P = 0.06). Mucin expression and the ratio between sulfated and nonsulfated ac idic mucins were not altered by inulin supplementation. CONCLUSION: hi this prospective study, inulin supplementation did not significantly alter pouc h mucosal functioning because neither epithelial homeostasis nor epithelial gene expression was significantly altered by enteral inulin.