Ezetimibe Attenuates Atherosclerosis Associated with Lipid Reduction and Inflammation Inhibition

BACKGROUND: Ezetimibe, as a cholesterol absorption inhibitor, has been shown protecting against atherosclerosis when combined with statin. However, side by side comparison has not been made to evaluate the beneficial effects of ezetimibe alone versus statin. Herein, the study aimed to test whether ezetimibe alone would exhibit similar effects as statin and the combination therapy would be necessary in a moderate lesion size. METHODS AND RESULTS: ApoE-/- male mice that were fed a saturated-fat supplemented diet were randomly assigned to different therapeutic regimens: vehicle, ezetimibe alone (10 mg/kg/day), atorvastatin (20 mg/kg/day) or combination of ezetimibe and atorvastatin through the drinking water. On 28 days, mice were sacrificed and aorta and sera were collected to analyze the atherosclerotic lesion and blood lipid and cholesterol levels. As a result, ezetimibe alone exerted similar protective effects on atherosclerotic lesion sizes as atorvastatin, which was mediated by lowering serum cholesterol concentrations, inhibiting macrophage accumulation in the lesions and reducing circulatory inflammatory cytokines, such as monocyte chemoattractant protein (MCP-1) and tumor necrosis factor (TNF-α). In contrast to ezetimibe administration, atorvastatin alone attenuated atherosclerotic lesion which is dependent on its anti-inflammation effects. There were no significance differences in lesion areas and serum concentrations of cholesterol, oxidized LDL and inflammatory cytokines between combination therapy and monotherapy (either ezetimibe or atorvastatin). There were significant correlations between the lesion areas and serum concentrations of cholesterol, MCP-1 and TNF-α, respectively. However, there were no significant correlations between the lesion areas and serum concentrations of TGF-β1 and oxLDL. CONCLUSIONS: Ezetimibe alone played the same protection against a moderate atherosclerotic lesion as atorvastatin, which was associated with lowering serum cholesterol, decreasing circulating inflammatory cytokines, and inhibiting macrophage accumulation in the lesions.