title: Serum metabolomic profiling in acute alcoholic hepatitis identifies multiple dysregulated pathways.
abstract: OBJECTIVE
  While animal studies have implicated derangements of global energy homeostasis in the pathogenesis of acute alcoholic hepatitis (AAH), the relevance of these findings to the development of human AAH remains unclear. Using global, unbiased serum metabolomics analysis, we sought to characterize alterations in metabolic pathways associated with severe AAH and identify potential biomarkers for disease prognosis.
  
  
  METHODS
  This prospective, case-control study design included 25 patients with severe AAH and 25 ambulatory patients with alcoholic cirrhosis. Serum samples were collected within 24 hours of the index clinical encounter. Global, unbiased metabolomics profiling was performed. Patients were followed for 180 days after enrollment to determine survival.
  
  
  RESULTS
  Levels of 234 biochemicals were altered in subjects with severe AAH. Random-forest analysis, principal component analysis, and integrated hierarchical clustering methods demonstrated that metabolomics profiles separated the two cohorts with 100% accuracy. Severe AAH was associated with enhanced triglyceride lipolysis, impaired mitochondrial fatty acid beta oxidation, and upregulated omega oxidation. Low levels of multiple lysolipids and related metabolites suggested decreased plasma membrane remodeling in severe AAH. While most measured bile acids were increased in severe AAH, low deoxycholate and glycodeoxycholate levels indicated intestinal dysbiosis. Several changes in substrate utilization for energy homeostasis were identified in severe AAH, including increased glucose consumption by the pentose phosphate pathway, altered tricarboxylic acid (TCA) cycle activity, and enhanced peptide catabolism. Finally, altered levels of small molecules related to glutathione metabolism and antioxidant vitamin depletion were observed in patients with severe AAH. Univariable logistic regression revealed 15 metabolites associated with 180-day survival in severe AAH.
  
  
  CONCLUSIONS
  Severe AAH is characterized by a distinct metabolic phenotype spanning multiple pathways. Metabolomics profiling revealed a panel of biomarkers for disease prognosis, and future studies are planned to validate these findings in larger cohorts of patients with severe AAH.
authors.affiliation: Department of Medicine, Divisions of Gastroenterology, Hepatology, and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
authors.forename: Vikrant
authors.initials: V
authors.lastname: Rachakonda
authors.affiliation: Department of Medicine, Divisions of Gastroenterology, Hepatology, and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
authors.forename: Charles
authors.initials: C
authors.lastname: Gabbert
authors.affiliation: Department of Medicine, Divisions of Gastroenterology, Hepatology, and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
authors.forename: Amit
authors.initials: A
authors.lastname: Raina
authors.affiliation: Metabolon, Inc., Durham, North Carolina, United States of America.
authors.forename: Lauren N
authors.initials: LN
authors.lastname: Bell
authors.affiliation: Hudson Alpha Institute for Biotechnology, Huntsville, Alabama, United States of America.
authors.forename: Sara
authors.initials: S
authors.lastname: Cooper
authors.affiliation: Department of Medicine, Divisions of Gastroenterology, Hepatology, and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
authors.forename: Shahid
authors.initials: S
authors.lastname: Malik
authors.affiliation: Department of Medicine, Divisions of Gastroenterology, Hepatology, and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
authors.forename: Jaideep
authors.initials: J
authors.lastname: Behari
mesh_terms: D000208:Acute Disease; D000273:Adipose Tissue / Q000473:pathology; D001647:Bile Acids and Salts / Q000097:blood; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D002462:Cell Membrane / Q000378:metabolism; D016000:Cluster Analysis; D064806:Dysbiosis / Q000097:blood; D004734:Energy Metabolism; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D005947:Glucose / Q000378:metabolism; D006519:Hepatitis, Alcoholic / Q000097:blood* / Q000378:metabolism*; D006801:Humans; D007249:Inflammation / Q000473:pathology; D050356:Lipid Metabolism; D016015:Logistic Models; D008297:Male; D053858:Metabolic Networks and Pathways; D055442:Metabolome; D055432:Metabolomics / Q000379:methods*; D008875:Middle Aged; D008928:Mitochondria / Q000378:metabolism; D010084:Oxidation-Reduction; D025341:Principal Component Analysis; D015262:Xenobiotics / Q000378:metabolism
chemical_list: D001647:Bile Acids and Salts; D015415:Biomarkers; D005227:Fatty Acids; D015262:Xenobiotics; D005947:Glucose