Bile acids as possible mediators of microbiome-host interaction

 

Introduction:

Gut microbiota have been shown to be involved in the development of obesity and type 2 diabetes (T2D). They metabolise bile acids, which have been suggested to play a role in fat and glucose metabolism through the interaction with FXR- and TGR5-receptors. Thus, bile acids should be evaluated as possible mediators of microbiome-host interaction with respect to T2D.

Patients and Methods:

We characterized 434 human subjects with different metabolic phenotypes (underweight, normal weight, obese without diabetes, obese with T2D) regarding their bile acids serum levels (LC-MS) and their gut microbial composition (16S rRNA gene sequencing). Obese and normal weight groups were matched by age and gender.

Results:

Abundances of 11 bile acids were analysed in human serum of the 4 study groups, whereas obese with T2D group differed most from other groups. In general bile acid levels were higher in obese with T2D. Especially serum levels of the secondary bile acids deoxycholic acid and glycodeoxycholic acid, which are built or dehydroxylated by the microbiota, appeared higher with increasing BMI over the groups. Highest prevalence was shown in obese with T2D. Correlation analyses revealed a positive association of Lactobacillus with deoxycholic acid and glycodeoxycholic acid, whereas Lactobacillus were significantly more abundant in obese subjects.

Conclusion:

Results of the present investigation proofed the importance of microbiota in bile acid status and indicate that bile acid serum levels are associated with obesity and T2D, suggesting bile acids as a possible target in future diabetes prevention/therapy.