Heart 7-hydroperoxycholesterol and oxysterols are elevated in chronically ethanol-fed rats

Recently, cholesterol hydroperoxides have been shown to be sensitive pathog enic markers of reactive oxygen species (ROS)-mediated damage though they h ave never been measured in heart tissue. We hypothesized that cholesterol h ydroperoxides and oxysterols, putative cardiotoxic products of cholesterol oxidation, are elevated in the hearts of alcoholics as a consequence of ROS -mediated reactions. To test this, we measured 7 alpha- and 7 beta -hydrope roxycholest-5-en-3 beta -ol (7 alpha -OOH and 7 beta -OOH) by HPLC with pos tcolumn chemiluminescence as well as 7 alpha- and 7 beta -hydroxycholestero l (7 alpha -OH and 7 beta -OH) and 3 beta -hydroxycholest-5-en-7-one (also termed 7-ketocholesterol; 7-keto) by HPLC-UV in cardiac muscle of alcohol-f ed rats. Alcohol feeding was carried out using a pair-feeding protocol with 35% of total dietary energy as ethanol; controls were pair-fed isocaloric glucose. After 6-7 wk treatment with alcohol, heart 7 alpha -OOH, 7 beta -O OH and 7 beta -OH were significantly greater than in controls. Levels of he art phospholipid 16:0 and 18:1 were lower than in controls, while-18:0 and 18:2 were greater. This is the first report of the presence of 7a-OOH, 7 be ta -OOH and 7a-OH in cardiac tissue. The elevations in 7 alpha -OOH and 7 b eta -OOH as well as 7 beta -OH are evidence of increased oxidative stress a nd possible membrane changes. Alterations in the proportions of 16:0, 18:1, 18:2 and 18:0 in heart phospholipids provide further evidence of an altere d membrane domain.