Bile Acid Metabolism in Extrahepatic Biliary Atresia

Lithocholic acid (LCA) is a potent hepatotoxic compound. Fetal LCA may have a role in the pathogenesis of neonatal cholestasis/extrahepatic biliary atresia (EHBA). Fetal liver efficiently hydroxylates LCA in several positions. This may represent a detox-ification mechanism. In the present study LCA, cholic acid (CA) and chenodeoxycholic acid (CDCA) were quantitated by gas chromatography-mass spectrometry using selected ion monitoring in small amounts of stored dried blood from six newborn infants with EHBA and fourteen con-trols. The blood was collected at neonatal metabolic screening. Mean blood levels (±S.E.M.) of LCA were 0.11±0.04 μM in the in-fants with EHBA and 0.08±0.02 μM in the control infants. The corresponding levels for CA and CDCA were 15.6±3.6 μM and 7.4±2.5 μM in the infants with EHBA and 1.7±0.3 μM and 1.8±0.4 μM in the controls. The increased levels of CA and CDCA in the infants with liver disease can be explained by cholestasis. The low blood levels of LCA indicate a normal fetal metabolism of this bile acid in EHBA.