Probiotic administration in patients with ileal pouch-anal anastomosis for ulcerative colitis is associated with expansion of mucosal regulatory cells

Background: Probiotics have anti-inflammatory effects in patients with inflammatory bowel disease and appear to regulate mucosal immune response through reductions in proinflammatory cytokines. The probiotic VSL#3 prevents pouchitis if started within a week of ileostomy closure and maintains remission following antibacterial treatment in patients with refractory or recurrent pouchitis. However, the efficacy of probiotics and their effects on regulatory cells if started at a greater time after surgery in patients undergoing ileal pouch anal anastomosis (IPAA) for ulcerative colitis are unknown. Methods: We conducted an open-label study in which 31 patients at different periods from surgery without signs and symptoms of pouchitis were randomized to 2 sachets of VSL#3 once daily or no treatment for 12 months. Pouchitis disease activity index (PDAI) was evaluated at baseline and after 3, 6, and 12 months. The percentage of CD4+ T lymphocytes expressing CD25 and the inactive form of transforming growth factor-beta [latency-associated peptide (LAP)] were evaluated at baseline and after 3 and 6 months in peripheral-blood mononuclear cells and mucosal biopsies. Variation in tissue interleukin-1 beta and Foxp3 mRNA expression was also evaluated. Results: During the study period, VSL#3-treated patients showed a significant reduction in PDAI score and a significant increase in the percentage of mucosal CD4+CD25(high) and CD4+ LAP-positive cells compared with baseline values. Tissue samples at different points showed a significant reduction in IL-1 beta mRNA expression, and a significant increase in Foxp3 mRNA expression. Conclusions: We conclude that VSL#3 administration in patients with IPAA modulates the PDAI and expands the number of mucosal regulatory T cells.