Metabolic signatures across the full spectrum of non-alcoholic fatty liver disease

• Published in: JHEP reports Vol. 4; no. 5; p. 100477
• Main Authors: McGlinchey, Aidan J., Govaere, Olivier, Geng, Dawei, Ratziu, Vlad, Allison, Michael, Bousier, Jerome, Petta, Salvatore, de Oliviera, Claudia, Bugianesi, Elisabetta, Schattenberg, Jörn M., Daly, Ann K., Hyötyläinen, Tuulia, Anstee, Quentin M., Orešič, Matej
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.05.2022; Elsevier
• Subjects: Fibrosis; Life Sciences; Lipidomics; Mass spectrometry; Metabolomics; Non-alcoholic steatohepatitis; FFA; Metabolomics; LM; NAS; T2DM; NAFLD; 3-HB; ALT; PC(O); FLIP; NRR; LDL; HSD; NIDDK NASH-CRN; SM; UHPLC; Non-alcoholic steatohepatitis; GC; NAFL; QTOFMS; 2-HB; AST; CE; LMC; ROC; Lipidomics; HCC; NASH; PCA; Cer; PC; TG; PE; Fibrosis; LC; SAF; Mass spectrometry; LPC; 3-HB, 3-hydroxybutanoic acid; CE, cholesterol ester; T2DM, type 2 diabetes mellitus; LPC, lysophosphatidylcholine; SM, sphingomyelin; LC, lipid cluster; SAF, steatosis, activity, and fibrosis; FFA, free fatty acid; PC(O), ether PC; PCA, principal component analysis; NAFLD, non-alcoholic fatty liver disease; QTOFMS, quadrupole-time-of-flight mass spectrometry; FLIP, Fatty Liver Inhibition of Progression; GC, gas chromatography; LDL, low-density lipoprotein; ALT, alanine aminotransferase; LM, lipid and metabolite; PC, phosphatidylcholine; ROC, receiving operator characteristic; NAFL, non-alcoholic fatty liver; NASH, non-alcoholic steatohepatitis; 2-HB, 2-hydroxybutanoic acid; PE, phosphatidylethanolamine; HSD, honest significant difference; Cer, ceramide; TG, triacylglycerol; NAS, NASH activity score; LMC, lipid, metabolite, and clinical variable; UHPLC, ultrahigh-performance liquid chromatography; HCC, hepatocellular carcinoma; AST, aspartate aminotransferase; NIDDK NASH-CRN, National Institute of Digestive Diseases and Kidney NASH Clinical Research Network; NRR, non-rejection rate
• ISSN: 2589-5559; 2589-5559
• DOI: 10.1016/j.jhepr.2022.100477

Non-alcoholic fatty liver disease (NAFLD) is a progressive liver disease with potentially severe complications including cirrhosis and hepatocellular carcinoma. Previously, we have identified circulating lipid signatures associating with liver fat content and non-alcoholic steatohepatitis (NASH). Here, we develop a metabolomic map across the NAFLD spectrum, defining interconnected metabolic signatures of steatosis (non-alcoholic fatty liver, NASH, and fibrosis). We performed mass spectrometry analysis of molecular lipids and polar metabolites in serum samples from the European NAFLD Registry patients (n = 627), representing the full spectrum of NAFLD. Using various univariate, multivariate, and machine learning statistical approaches, we interrogated metabolites across 3 clinical perspectives: steatosis, NASH, and fibrosis. Following generation of the NAFLD metabolic network, we identify 15 metabolites unique to steatosis, 18 to NASH, and 15 to fibrosis, with 27 common to all. We identified that progression from F2 to F3 fibrosis coincides with a key pathophysiological transition point in disease natural history, with n = 73 metabolites altered. Analysis of circulating metabolites provides important insights into the metabolic changes during NAFLD progression, revealing metabolic signatures across the NAFLD spectrum and features that are specific to NAFL, NASH, and fibrosis. The F2–F3 transition marks a critical metabolic transition point in NAFLD pathogenesis, with the data pointing to the pathophysiological importance of metabolic stress and specifically oxidative stress. The study is registered at Clinicaltrials.gov (NCT04442334). Non-alcoholic fatty liver disease is characterised by the build-up of fat in the liver, which progresses to liver dysfunction, scarring, and irreversible liver failure, and is markedly increasing in its prevalence worldwide. Here, we measured lipids and other small molecules (metabolites) in the blood with the aim of providing a comprehensive molecular overview of fat build-up, liver fibrosis, and diagnosed severity. We identify a key metabolic ‘watershed’ in the progression of liver damage, separating severe disease from mild, and show that specific lipid and metabolite profiles can help distinguish and/or define these cases. [Display omitted] •We assembled a highly phenotyped and characterised cohort of patients with NAFLD across the full spectrum of NAFLD.•Lipidomic and metabolomic interrogation of this dataset reveals crucial metabolic tipping point of NAFLD at fibrosis stage F2–F3.•NAFLD processes of fibrosis, steatosis, and NASH progression parallel distinct changes in metabolomic profiles.•Oxidative stress-buffering potential of the liver via ether lipids appears 1 of the key changes en route to late-stage NASH.