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-1beta 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-1beta 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.

TGF-beta1 production in inflammatory bowel disease: differing production patterns in Crohn's disease and ulcerative colitis

Transforming growth factor-beta (TGF-beta) is an inhibitory cytokine recognized as a key regulator of immunological homeostasis and inflammatory responses. TGF-beta is involved in experimental models of oral tolerance and in the pathogenesis of experimental colitis. Patients with inflammatory bowel disease (IBD) have inappropriate T cell responses to antigenic components of their own intestinal microflora, suggesting the presence of a disorder in the normal mucosal immune mechanism that ensures the down-regulation of responses to harmless constituents in the microflora. To evaluate the contribution of TGF-beta to this imbalance, we measured TGF-beta1 production by lamina propria mononuclear cells (LPMC) and T cells isolated from tissue specimens of patients with Crohn's disease (CD), ulcerative colitis (UC) and controls. Cells were cultured in the presence or absence of anti-CD2 plus anti-CD28 MoAbs and TGF-beta1 production in culture supernatants was measured by ELISA. LPMC isolated from CD patients produced significantly less TGF-beta1 than controls when stimulated via CD2 plus CD28 pathways (P = 0.001)] conversely, in UC patients increased production of TGF-beta1 compared to controls was observed (P = 0.0005). These differences were also observed with purified lamina propria (LP) T cells in both diseases and were associated with the presence of inflammation. Thus, TGF-beta1 production shows contrasting secretion in CD and in UC, probably as a consequence of the different Th polarization. The absolute or relative defect in TGF-beta1 production observed in CD and UC may contribute to the perpetuation of inflammation.