Serum bile acid profiling reflects enterohepatic detoxification state and intestinal barrier function in inflammatory bowel disease

AIM： To determine free and conjugated serum bile acid （BA） levels in inflammatory bowel disease （IBD） subgroups with defined clinical manifestations. METHODS： Comprehensive serum BA profiling was performed in 358 IBD patients and 310 healthy con- trols by liquid chromatography coupled to electrospray ionization tandem mass spectrometry. RESULTS： Serum levels of hyodeoxycholic acid, the CYP3A4-mediated detoxification product of the second- ary BA lithocholic acid （LCA）, was increased significantly in Crohn＇s disease （CD） and ulcerative colitis （UC）, while most other serum BA species were decreased signifi- cantly. Total BA, total BA conjugate, and total BA glyco- conjugate levels were decreased only in CD, whereas total unconjugated BA levels were decreased only in UC. In UC patients with hepatobiliary manifestations, the conjugated primary BAs glycocholic acid, taurocholic acid, and glycochenodeoxycholic acid were as signifi- cantly increased as the secondary BAs LCA, ursodeoxy- cholic acid, and tauroursodeoxycholic acid compared to UC patients without hepatobiliary manifestations. Finally, we found that in ileocecal resected CD patients, the unconjugated primary BAs, cholic acid and chenode- oxycholic acid, were increased significantly compared to controls and patients without surgical interventions. CONCLUSION： Serum BA profiling in IBD patients that indicates impaired intestinal barrier function and increased detoxification is suitable for advanced diag- nostic characterization and differentiation of IBD sub- groups with defined clinical manifestations.