Ursodeoxycholic acid and its taurine/glycine conjugated species reduce colitogenic dysbiosis and equally suppress experimental colitis in mice.

Abstract

The promising results with secondary bile acids in experimental colitis suggest that they may represent an attractive and safe class of drugs for the treatment of inflammatory bowel diseases (IBD). However, the exact mechanism by which bile acid therapy confers protection from colitogenesis is currently unknown. Since the gut microbiota plays a crucial role in the pathogenesis of IBD, and exogenous bile acid administration may affect the community structure of the microbiota, we examined the impact of the secondary bile acid ursodeoxycholic acid (UDCA) and its taurine/glycine conjugates on the fecal microbial community structure during experimental colitis. Daily oral administration of UDCA, tauroursodeoxycholic acid (TUDCA) or glycoursodeoxycholic acid (GUDCA) equally lowered the severity of dextran sodium sulfate-induced colitis in mice, as evidenced by reduced body weight loss, colonic shortening and expression of inflammatory cytokines. Illumina sequencing demonstrated that bile acid therapy during colitis did not restore fecal bacterial richness and diversity. However, bile acid therapy normalized the colitis-associated increased ratio of Firmicutes to Bacteroidetes Interestingly, administration of bile acids prevented the loss of Clostridium cluster XIVa and increased the abundance of Akkermansia muciniphila, bacterial species known to be particularly decreased in IBD patients. We conclude that UDCA, which is an FDA-approved drug for cholestatic liver disorders, could be an attractive treatment option to reduce dysbiosis and improve inflammation in human IBD.