Ezetimibe inhibits the incorporation of dietary oxidized cholesterol into lipoproteins

Ilona Staprans¹^,*^,, Xian-Mang Pan^*^,, Joseph H. Rapp^*^,, Arthur H. Moser^*^, and Kenneth R. Feingold^*^,

^* Department of Veterans Affairs Medical Center, University of California, San Francisco, CA
Department of Surgery, University of California, San Francisco, CA
Department of Medicine, University of California, San Francisco, CA

Published, JLR Papers in Press, August 7, 2006.

^¹ To whom correspondence should be addressed. e-mail: ilona.staprans{at}ucsf.edu

ABSTRACT

Oxidized cholesterol is present in significant quantities inthe typical Western diet. When ingested, oxidized cholesterolis absorbed by the small intestine and incorporated into bothchylomicrons and LDL, resulting in LDL that is more susceptibleto further oxidation. Feeding studies in animal models and epidemiologicalstudies in humans have suggested that oxidized cholesterol inthe diet increases the development of atherosclerosis. In thisstudy, we determined the effect of ezetimibe, a drug that inhibitssmall intestinal absorption of cholesterol, on the levels ofoxidized cholesterol in the serum after a test meal containingoxidized cholesterol. We demonstrate that ezetimibe, 10 mg perday for 1 month, markedly reduced the levels (50% decrease)of oxidized cholesterol in the serum after feeding a test mealcontaining either ${alpha}$ -epoxy cholesterol or 7-keto cholesterol,two of the predominant oxidized cholesterols found in the diet.Moreover, the decrease in oxidized cholesterol in the serumwas attributable to a decrease in the incorporation of dietaryoxidized cholesterol into both chylomicrons and LDL. Becausethere was no decrease in postprandial triglyceride levels, weconclude that this decrease in oxidized cholesterol levels inthe serum is attributable to decreased absorption and not toenhanced clearance. Whether this decrease in oxidized cholesterolabsorption prevents or delays the development of atherosclerosisremains to be determined.

Supplementary key words oxidized lipoproteins • diet • cholesterol absorption • ${alpha}$ -epoxy cholesterol • 7-keto cholesterol

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Ezetimibe inhibits the incorporation of dietary oxidized cholesterol into lipoproteins