Identification of 7-hydroperoxycholesterol in human liver by liquid chromatography-mass spectrometry

Background: A liquid chromatography-mass spectrometry with an atmospheric chemical ionization interface has been developed to identify simultaneously various oxygenated cholesterols in lipid extracts from alcoholic fatty liver. Methods: We collected human liver tissues from alcoholic and control subjects at autopsy. We purified the lipid extracts with solid phase extraction and injected them onto a spherisorb ODS column, by using methanol that contained 10 mM ammonium acetate as a mobile phase and a flow rate of 0.7 ml/min. Results: We found the presence of 7-hydroperoxycholesterol and other oxysterols (5-cholesten-3 beta-ol-7-one, cholest-5-ene-3 beta, 7-diol, and 5, 6 beta-epoxy-5 beta-cholestan-3 beta-ol) in alcoholic fatty liver tissues. Conclusions: We assume that long-term ethanol ingestion leads to excessive oxidative stress and to the accumulation of cholesterol-derived hydroperoxides and oxysterols in alcoholic fatty liver.