Bile acids play an important role in regulating gut microbiome
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Loading... - Kumi Mintah
- 29 Sep 2022
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In a recent Microorganisms journal study, scientists performed in vitro and in vivo experiments to investigate the antimicrobial effects of different bile acids on various microorganisms.
Bile acids
Primary bile acids are synthesized from cholesterol in the liver, which is transformed to cholic acid (CA) through the classical pathway and chenodeoxycholic acid (CDCA) as an alternative pathway.
Primary bile acids are dehydroxylated by the intestinal microbiota to form secondary bile acids. Generally, deoxycholic acid (DCA) and lithocholic acid (LCA) are regarded as secondary bile acids. Most bile is re-absorbed in the small intestine, while 5% is excreted in the stool.
Bile acids in the GI tract
Every bile acid affects the intestinal microbiota differentially. For example, some bile acids exhibit bactericidal and bacteriostatic effects against microbes.
Bile acids disrupt bacterial membranes and damage their DNA. Furthermore, these acids regulate host immunity by controlling nuclear receptors, such as the farnesoid X receptor (FXR) and vitamin D receptor (VDR).
Microorganisms counter the antimicrobial effects of bile acids through several mechanisms, such as modulation of the efflux system, stress responses, DNA repair, and cell envelope remodeling. Additionally, intestinal microorganisms also play an important role in intestinal bile acid composition by deconjugation, dihydroxylation, and epimerization. The interactions between intestinal microbiota and bile acids help maintain intestinal homeostasis.
Supplementation of specific bile acids, such as ursodeoxycholic acid (UDCA), has certain therapeutic indications. Constant supplementation of specific bile acids affects the bile acid composition of the intestinal tracts, thus altering the intestinal microbiota diversity. Read More...
