Bilirubin Metabolism Does Not Influence Serum Bile Acid Profiles According to LC-MS: A Human Case-Control Study

In addition to their role in lipid absorption, bile acids (BAs) are also known for several relevant (endocrine) activities including contributing to the regulation of energy homeostasis and some non-communicable diseases (NCDs). Furthermore, moderately elevated unconjugated bilirubin levels, as observed in Gilbert's syndrome (GS), may protect against NCDs. We therefore hypothesized that the BA profile in GS subjects differs from that of normo-bilirubinemic individuals. To test this, we performed a human case-control study, in which GS (n = 60) and controls (n = 60) were matched for age and gender, and serum BA concentrations were measured by liquid-chromatography mass spectrometry (LC-MS). Despite analyzing a comprehensive panel of BAs, no significant differences between the two groups were observed. These data suggest that bile acid concentrations are similar between groups, indicating that altered bilirubin metabolism unlikely influences their transport into the blood.