Metabolic Profiling of Bile Acids in the Urine of Patients with Alcohol‐Associated Liver Disease

Bile acids (BAs) play important functions in the development of alcohol‐associated liver disease (ALD). In the current study, urine BA concentrations in 38 patients with well‐described alcohol‐associated hepatitis (AH) as characterized by Model for End‐Stage Liver Disease (MELD), 8 patients with alcohol‐use disorder (AUD), and 19 healthy controls (HCs) were analyzed using liquid chromatography–mass spectrometry. Forty‐three BAs were identified, and 22 BAs had significant changes in their abundance levels in patients with AH. The potential associations of clinical data were compared to candidate BAs in this pilot proof‐of‐concept study. MELD score showed positive correlations with several conjugated BAs and negative correlations with certain unconjugated BAs; taurine‐conjugated chenodeoxycholic acid (CDCA) and MELD score showed the highest association. Cholic acid, CDCA, and apocholic acid had nonsignificant abundance changes in patients with nonsevere ALD compared to HCs but were significantly increased in those with severe AH. Receiver operating characteristic analysis showed that the differences in these three compounds were sufficiently large to distinguish severe AH from nonsevere ALD. Notably, the abundance levels of primary BAs were significantly increased while most of the secondary BAs were markedly decreased in AH compared to AUD. Most importantly, the amount of total BAs and the ratio of primary to secondary BAs increased while the ratio of unconjugated to conjugated BAs decreased as disease severity increased. Conclusion: Abundance changes of specific BAs are closely correlated with the severity of AH in this pilot study. Urine BAs (individually or as a group) could be potential noninvasive laboratory biomarkers for detecting early stage ALD and may have prognostic value in AH morbidity.