¹H and ³¹P NMR lipidome of ethanol-induced fatty liver.
BACKGROUND
Hepatic steatosis (fatty liver), an early and reversible stage of alcoholic liver disease, is characterized by triglyceride deposition in hepatocytes, which can advance to steatohepatitis, fibrosis, cirrhosis, and ultimately to hepatocellular carcinoma. In the present work, we studied altered plasma and hepatic lipid metabolome (lipidome) to understand the mechanisms and lipid pattern of early-stage alcohol-induced-fatty liver.


METHODS
Male Fischer 344 rats were fed 5% alcohol in a Lieber-DeCarli diet. Control rats were pair-fed an equivalent amount of maltose-dextrin. After 1 month, animals were killed and plasma collected. Livers were excised for morphological, immunohistochemical, and biochemical studies. The lipids from plasma and livers were extracted with methyl-tert-butyl ether and analyzed by 750/800 MHz proton nuclear magnetic resonance (¹H NMR) and phosphorus (³¹P) NMR spectroscopy on a 600 MHz spectrometer. The NMR data were then subjected to multivariate statistical analysis.


RESULTS
Hematoxylin and Eosin and Oil Red O stained liver sections showed significant fatty infiltration. Immunohistochemical analysis of liver sections from ethanol-fed rats showed no inflammation (absence of CD3 positive cells) or oxidative stress (absence of malondialdehyde reactivity or 4-hydroxynonenal positive staining). Cluster analysis and principal component analysis of ¹H NMR data of lipid extracts of both plasma and livers showed a significant difference in the lipid metabolome of ethanol-fed versus control rats. ³¹P NMR data of liver lipid extracts showed significant changes in phospholipids similar to ¹H NMR data. ¹H NMR data of plasma and liver reflected several changes, while comparison of ¹H NMR and ³¹P NMR data offered a correlation among the phospholipids.


CONCLUSIONS
Our results show that alcohol consumption alters metabolism of cholesterol, triglycerides, and phospholipids that could contribute to the development of fatty liver. These studies also indicate that fatty liver precedes oxidative stress and inflammation. The similarities observed in plasma and liver lipid profiles offer a potential methodology for detecting early-stage alcohol-induced fatty liver disease by analyzing the plasma lipid profile.
Fernando
Harshica
H
Department of Pathology, The University of Texas Medical Branch, Galveston, Texas 77030, USA.
Kondraganti
Shakuntala
S
Bhopale
Kamlesh K
KK
Volk
David E
DE
Neerathilingam
Muniasamy
M
Kaphalia
Bhupendra S
BS
Luxon
Bruce A
BA
Boor
Paul J
PJ
Shakeel Ansari
G A
GA
D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D001835:Body Weight / Q000187:drug effects; D002492:Central Nervous System Depressants / Q000494:pharmacology; D056486:Chemical and Drug Induced Liver Injury / Q000473:pathology; D016000:Cluster Analysis; D003627:Data Interpretation, Statistical; D000431:Ethanol / Q000494:pharmacology; D005235:Fatty Liver, Alcoholic / Q000378:metabolism* / Q000473:pathology; D007150:Immunohistochemistry; D050356:Lipid Metabolism / Q000187:drug effects*; D008055:Lipids / Q000097:blood; D008099:Liver / Q000187:drug effects / Q000473:pathology; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009929:Organ Size / Q000187:drug effects; D018384:Oxidative Stress / Q000502:physiology; D010759:Phosphorus Isotopes; D025341:Principal Component Analysis; D011522:Protons; D051381:Rats; D011916:Rats, Inbred F344
D002492:Central Nervous System Depressants; D008055:Lipids; D010759:Phosphorus Isotopes; D011522:Protons; D000431:Ethanol; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase