Hepatic lipid profiling of deer mice fed ethanol using 1H and 31P NMR spectroscopy: A dose-dependent subchronic study

• Published in: Toxicology and applied pharmacology 2012-11, Vol.264 (3), p.361-369
• Main Authors: Fernando, Harshica, Bhopale, Kamlesh K., Boor, Paul J., Ansari, G.A. Shakeel, Kaphalia, Bhupendra S.
• Format: Article
• Language: English
• Subjects: Alcohol dehydrogenase; Alcoholic liver disease; Alcoholics; Alcoholism and acute alcohol poisoning; Animal models; Animals; Biological and medical sciences; biomarkers; Cholesterol; Cholesterol - blood; Cholesterol Esters - blood; Data processing; Deer mice; Dose-Response Relationship, Drug; Drug Administration Schedule; Ethanol; Ethanol - administration & dosage; Ethanol - toxicity; fatty acid methyl esters; Fatty Acids - blood; Fatty liver; Gastroenterology. Liver. Pancreas. Abdomen; Lipid Metabolism - drug effects; Lipidomics; Lipids; Liver - drug effects; Liver - metabolism; Liver diseases; Liver Diseases, Alcoholic - metabolism; Liver. Biliary tract. Portal circulation. Exocrine pancreas; Magnetic resonance spectroscopy; Magnetic Resonance Spectroscopy - methods; Male; Medical sciences; Metabolic pathways; metabolomics; Mortality; N.M.R; Other diseases. Semiology; Peromyscus; Phospholipids; Protons; steatosis; Toxicology
• ISSN: 0041-008X; 1096-0333
• DOI: 10.1016/j.taap.2012.07.026

Chronic alcohol abuse is a 2nd major cause of liver disease resulting in significant morbidity and mortality. Alcoholic liver disease (ALD) is characterized by a wide spectrum of pathologies starting from fat accumulation (steatosis) in early reversible stage to inflammation with or without fibrosis and cirrhosis in later irreversible stages. Previously, we reported significant steatosis in the livers of hepatic alcohol dehydrogenase (ADH)-deficient (ADH−) vs. hepatic ADH-normal (ADH+) deer mice fed 4% ethanol daily for 2months [Bhopale et al., 2006, Alcohol 39, 179–188]. However, ADH− deer mice fed 4% ethanol also showed a significant mortality. Therefore, a dose-dependent study was conducted to understand the mechanism and identify lipid(s) involved in the development of ethanol-induced fatty liver. ADH− and ADH+ deer mice fed 1, 2 or 3.5% ethanol daily for 2months and fatty infiltration in the livers were evaluated by histology and by measuring dry weights of extracted lipids. Lipid metabolomic changes in extracted lipids were determined by proton (1H) and 31phosphorus (31P) nuclear magnetic resonance (NMR) spectroscopy. The NMR data was analyzed by hierarchical clustering (HC) and principle component analysis (PCA) for pattern recognition. Extensive vacuolization by histology and significantly increased dry weights of total lipids found only in the livers of ADH− deer mice fed 3.5% ethanol vs. pair-fed controls suggest a dose-dependent formation of fatty liver in ADH− deer mouse model. Analysis of NMR data of ADH− deer mice fed 3.5% ethanol vs. pair-fed controls shows increases for total cholesterol, esterified cholesterol, fatty acid methyl esters (FAMEs), triacylglycerides and unsaturation, and decreases for free cholesterol, phospholipids and allylic and diallylic protons. Certain classes of neutral lipids (cholesterol esters, fatty acyl chain (COCH2) and FAMEs) were also mildly increased in ADH− deer mice fed 1 or 2% ethanol. Only small increases were observed for allylic and diallylic protons, FAMEs and unsaturations in ADH+ deer mice fed 3.5% ethanol vs. pair-fed controls. PCA of NMR data showed increased clustering by gradual separation of ethanol-fed ADH− deer mice groups from their respective pair-fed control groups and corresponding ethanol-fed ADH+ deer mice groups. Our data indicate that dose of ethanol and hepatic ADH deficiency are two key factors involved in initiation and progression of alcoholic fatty liver disease. Further studies on