Discovery of common urinary biomarkers for hepatotoxicity induced by carbon tetrachloride, acetaminophen and methotrexate by mass spectrometry-based metabolomics

Liver toxicity represents an important healthcare issue because it causes significant morbidity and mortality and can be difficult to predict before symptoms appear owing to drug therapy or exposure to toxicants. Using metabolomic techniques, we discovered common biomarkers for the prediction of hepatotoxicity in rat urine using mass spectrometry. For this purpose, liver toxicity was induced by 5 days of oral administration of carbon tetrachloride (1 ml kg^?1 per day), acetaminophen (1000 mg kg^?1 per day) and methotrexate (50 mg kg^?1 per day). Serum levels of alkaline phosphatase aspartate aminotransferase, alanine aminotransferase and histopathology in liver tissue were then checked to demonstrate liver toxicity. Global metabolic profiling with UPLC‐TOF‐MS (ultraperformance liquid chromatography–mass spectrometry), multivariate analysis (partial least square‐discriminant analysis, hierarchical analysis) and database searching were performed to discover common biomarkers for liver toxicity induced by these three compounds. Urinary concentrations of the newly discovered biomarkers were then quantified to confirm them as biomarkers of hepatotoxicity with targeted metabolic profiling using GC (gas chromatography)–MS and CE (capillary electrophoresis)–MS. In the results, steroids, amino acids and bile acids were metabolically changed between the control and drug‐treated groups in global metabolic profiling; 11β‐hydroxyandrosterone, epiandrosterone, estrone, 11‐dehydrocorticosterone, glycine, alanine, valine, leucine, dl ‐ornithine, 3‐methylhistidine, cholic acid and lithocholic acid were selected as liver toxicity biomarkers after performing targeted metabolic profiling. In conclusion, we discovered metabolite biomarkers belonging to three different metabolic pathways to check for liver toxicity with mass spectrometry from a metabolomics study that could be used to evaluate hepatotoxicity induced by drugs or other toxic compounds. Copyright © 2011 John Wiley & Sons, Ltd.