Cholesteryl ester enrichment of plasma low-density lipoproteins in hamsters fed cereal-based diets containing cholesterol

Male Syrian hamsters were fed 0.02, 0.03, or 0.05% cholesterol to test the hypothesis that moderate cholesterol intake increases the cholesteryl ester content of the plasma low-density lipoproteins (LDL). Dietary cholesterol levers of 0.02%-0.05% were chosen to reflect typical human Intakes of chole sterol. Hamsters were fed ad libitum a cereal based diet (modified NIH-07 o pen formula) for 15 weeks. Increasing dietary cholesterol from 0.02% to 0.0 5% resulted in significantly increased plasma LDL and high-density lipoprot ein cholesterol concentration, increased liver cholesterol concentration, a nd increased Petal aorta cholesterol content. The cholesteryl ester content of plasma LDL was determined as the molar ratio of cholesteryl ester to ap olipoprotein B and to surface lipid (i.e., phospholipid + free cholesterol) . Increasing dietary cholesterol from 0.02% to 0.05% resulted In significan tly increased cholesteryl ester content of LDL particles. Furthermore, chol esteryl ester content of LDL was directly associated with increased total a orta cholesterol, whereas a linear relationship between plasma LDL choleste rol concentration and aorta cholesterol was not observed. Thus, the data su ggest that LDL cholesteryl eater content may be an important atherogenic fe ature of plasma LDL.