Bad "Good" Bile Acids and Gut Microbiota Dysbiosis in Inflammatory Bowel Disease: Mice and Humans Are Not the Same.

The effects of deoxycholic acid (DCA) on the intestinal microbiota, bile acid (BA) metabolism, and intestinal epithelium can be influenced by various factors. Depending on the specific conditions, DCA can be "bad" (proinflammatory) or "good" (anti-inflammatory). Mouse models of colitis show an increase in conjugated BAs and gut dysbiosis, including DCA-related dysbiosis, with a significant decrease in bile salt hydrolase (bsh) gene-containing taxa. Human patients with inflammatory bowel disease demonstrate, primarily, a decrease in bile acid-inducible (bai) gene-containing taxa and a deficiency in secondary BAs, suggesting their anti-inflammatory role.