A 4-strain probiotic supplement influences gut microbiota composition and gut wall function in patients with ulcerative colitis.

Symprove, a multi-strain probiotic, has been shown to exert a mild anti-inflammatory effect in patients with ulcerative colitis (UC). We examined stool samples from 3 patients with UC in order to create microbiotas in an in-vitro gut model. The effects of Symprove on bacterial diversity and metabolic activity in the microbiotas was evaluated over 48 h. In addition, the influence of probiotic dosing on epithelial tight-junction integrity, production of inflammatory markers and wound healing were evaluated in cell culture models. The relative proportions of the main bacterial phyla in UC patients differed from those of healthy subjects studied previously; levels of Firmicutes were lowered and levels of Bacteroidetes were raised. Addition of Symprove changed the bacterial composition in the microbiotas over a 48 h period. Several other factors generally implicated in good gut health changed after dosing with probiotic; production of short chain fatty acids (SCFAs) and lactate was stimulated, levels of anti-inflammatory cytokines (IL-6, IL-10) increased, levels of pro-inflammatory cytokines and chemokines (MCP-1 and IL-8) decreased, epithelial tight junction integrity improved and wound healing occurred faster than a control. The results imply it is not the simple addition of probiotic bacteria that improves gut health. Rather, the probiotic bacteria generate lactate, which then stimulates growth of commensal gut bacteria, raising SCFA levels (particularly butyrate). The increased butyrate concentration positively influences inflammation response and time of wound healing.