Factors associated with ileal mucosal morphology and inflammation in patients with ileal pouch-anal anastomosis for ulcerative colitis.

PURPOSE: Pouchitis has been associated with abnormal bacterial flora responding to antibiotics. Dietary factors may play a role in modifying the qualitative and quantitative components of the microflora. We evaluated interactions between nutritional factors, fecal and mucosal bacterial flora, and mucosal morphology in patients with a history of pouchitis compared with patients with optimal outcome at least five years after ileal pouch-anal anastomosis for ulcerative colitis.

METHODS: Thirty-two patients were enrolled in the study: 11 (7 males; mean age, 49.8 years) with optimal outcome and 21 (11 males; mean age, 47.3 years) with pouchitis history. A seven-day food diary was recorded, endoscopy performed, and biopsies taken from the pouch for histology, mucin staining, and bacterial culture. Fresh fecal samples were quantitatively cultured, and fecal bile acids analyzed by gas-liquid chromatography.

RESULTS: No differences existed in mean nutrient intake, composition of fecal bile acids, or microbial tissue biopsy cultures between the groups with and without pouchitis. Those with optimal outcome tended to have more benign disease course of ulcerative colitis than patients with pouchitis. In those patients, fecal concentrations (log10 colony-forming unit/g) of anaerobes and aerobes were significantly higher (P = 0.007). Degree of villous atrophy and colonic metaplasia were both associated with fecal anaerobic flora. Low intake of lactose was associated with sulfomucin predominance. A negative correlation existed between fecal aerobes and dietary lactose consumption.

CONCLUSIONS: A higher total load of fecal anaerobic bacterial flora is strongly associated with degree of colonic metaplasia, villous atrophy, and inflammation activity after surgery for ulcerative colitis. An association existed between dietary lactose, fecal bacteria, and pouch morphology. Lactose may have prebiotic properties.