Predictive Value of Cellular Accumulation of Hydrophobic Bile Acids as a Marker of Cholestatic Drug Potential.

Drug-induced cholestasis is mostly intrahepatic and characterized by alterations of bile canaliculi dynamics and morphology as well as accumulation of bile acids (BAs) in hepatocytes. However, little information exists on first changes in BA content and profile induced by cholestatic drugs in human liver. In this study, we aimed to analyze the effects of a large set of cholestatic and noncholestatic drugs in presence of physiological serum concentrations and 60-fold higher levels of 9 main BAs on cellular accumulation of BAs using HepaRG hepatocytes. BAs were measured in cell layers (cells + bile canaliculi) and culture media using high-pressure liquid chromatography coupled with tandem mass spectrometry after 24 h-treatment. Comparable changes in total and individual BA levels were observed in cell layers and media from control and noncholestatic drug-treated cultures: unconjugated BAs were actively amidated and lithocholic acid (LCA) was entirely sulfated. In contrast, cellular accumulation of LCA and in addition, of the 2 other hydrophobic BAs, chenodeoxycholic acid and deoxycholic acid, was evidenced only with cholestatic compounds in presence of BA mixtures at normal and 60-fold serum levels, respectively, suggesting that LCA was the first BA to accumulate. Cellular accumulation of hydrophobic BAs was associated with inhibition of their amidation and for LCA, its sulfation. In conclusion, these results demonstrated that cellular accumulation of unconjugated hydrophobic BAs can be caused by various cholestatic drugs in human hepatocytes and suggest that their cellular detection, especially that of LCA, could represent a new strategy for evaluation of cholestatic potential of drugs and other chemicals.