Bile acid derivatives effectively prevented high-fat diet-induced colonic barrier dysfunction

SCOPE

Bile acids (BAs) have recently emerged as important regulators of many physiological and pathological processes. However, the change of colonic BAs induced by high-fat diet (HFD) and their effects on colonic barrier function remain to be further elucidated.

METHODS AND RESULTS

C57BL/6 mice were divided into two groups and feed 12 weeks with diets differing for fat content. Higher levels of serum DAO activity, ET and D-LA were observed in HFD-fed mice, indicating an increase in intestinal permeability. Real-time quantitative PCR and western blot analyses demonstrated that HFD downregulated tight junction proteins (TJs, including ZO-1, Occludin and Claudin1) and Muc2 expression in the colon. The colonic BA profiles were analyzed by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). HFD induced an increase in primary BAs but a decrease in secondary BAs. In human colonic cell line Caco-2, secondary BAs (DCA, LCA, their 3-oxo- and iso- derivates) upregulated the expression of TJs and counteracted DSS-induced increase in intestinal permeability at physiological concentrations. IsoDCA and isoLCA were the most effective ones. Moreover, supplementation of isoDCA or isoLCA also effectively prevented HFD-induced colonic barrier dysfunction in mice.

CONCLUSION

Our results demonstrated that secondary BAs (especially isomerized derivatives) may be important protectors for the colonic barrier function. This article is protected by copyright. All rights reserved.