Review: microbial transformations of human bile acids

Area of Science:

• Microbiology
• Biochemistry
• Gastroenterology

Background:

• Bile acids are crucial for gut metabolism, signaling, and microbiome composition.
• The liver produces primary bile acids, which gut microbes then modify into diverse secondary forms.
• Microbial transformations include deconjugation, dehydroxylation, dehydrogenation, and epimerization, linked to diseases like IBD and cancer.

Purpose of the Study:

• To review recent discoveries in microbial bile acid transformations.
• To explore the chemical diversity of bile acids, including newly identified microbially conjugated forms.
• To highlight the implications of these findings for host physiology and microbial dynamics.

Main Methods:

• Review of recent scientific literature on bile acid metabolism by gut microbiota.
• Analysis of established microbial bile acid transformation pathways.
• Inclusion of novel findings on microbially conjugated bile acids.

Main Results:

• Gut microbes extensively modify bile acids through known pathways.
• A novel pathway of microbial amino acid conjugation to bile acids has been identified.
• This expands the known chemical diversity of bile acids in the mammalian gut.

Conclusions:

• Microbial processing significantly diversifies bile acid structures.
• The newly discovered microbially conjugated bile acids represent a new class of bioactive molecules.
• Further research is needed to understand the physiological and microbial impacts of these novel bile acids.