Braun Anne, Yesilaltay Ayce, Acton Susan, Broschat Kay O, Krul Elaine S, Napawan Nida, Stagliano Nancy, Krieger Monty
Department of Biology, Massachusetts Institute of Technology, Building 68-483, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
Atherosclerosis. 2008 May;198(1):77-84. doi: 10.1016/j.atherosclerosis.2007.10.012. Epub 2007 Dec 3.
SR-BI/apoE double knockout (dKO) mice exhibit many features of human coronary heart disease (CHD), including hypercholesterolemia, occlusive coronary atherosclerosis, cardiac hypertrophy, myocardial infarctions, cardiac dysfunction and premature death. Ezetimibe is a FDA-approved, intestinal cholesterol absorption inhibitor that lowers plasma LDL cholesterol in humans and animals and inhibits aortic root atherosclerosis in apoE KO mice, but has not been proven to reduce CHD. Three-week-ezetimibe treatment of dKO mice (0.005% (w/w) in standard chow administered from weaning) resulted in a 35% decrease in cholesterol in IDL/LDL-size lipoproteins, but not in VLDL- and HDL-size lipoproteins. Ezetimibe treatment significantly reduced aortic root (57%) and coronary arterial (68%) atherosclerosis, cardiomegaly (24%) and cardiac fibrosis (57%), and prolonged the lives of the mice (27%). This represents the first demonstration of beneficial effects of ezetimibe treatment on CHD. The dKO mice were similarly treated with SC-435 (0.01% (w/w)), an apical sodium codependent bile acid transporter (ASBT) inhibitor, that blocks intestinal absorption of bile acids, lowers plasma cholesterol in animals, and reduces aortic root atherosclerosis in apoE KO mice. The effects of SC-435 treatment were similar to those of ezetimibe: 37% decrease in ILD/LDL-size lipoprotein cholesterol and 57% prolongation in median lifespan. Thus, inhibition of intestinal absorption of either cholesterol (ezetimibe) or bile acids (SC-435) significantly reduced plasma IDL/LDL-size lipoprotein cholesterol levels and improved survival of SR-BI/apoE dKO mice. The SR-BI/apoE dKO murine model of atherosclerotic occlusive, arterial CHD appears to provide a useful system to evaluate compounds that modulate cholesterol homeostasis and atherosclerosis.
SR-BI/载脂蛋白E双敲除(dKO)小鼠表现出许多人类冠心病(CHD)的特征,包括高胆固醇血症、闭塞性冠状动脉粥样硬化、心脏肥大、心肌梗死、心脏功能障碍和过早死亡。依泽替米贝是一种经美国食品药品监督管理局(FDA)批准的肠道胆固醇吸收抑制剂,可降低人和动物的血浆低密度脂蛋白胆固醇,并抑制载脂蛋白E基因敲除(apoE KO)小鼠的主动脉根部动脉粥样硬化,但尚未被证明可降低冠心病风险。对dKO小鼠进行为期三周的依泽替米贝治疗(从断奶开始在标准饲料中添加0.005%(w/w)),导致IDL/LDL大小脂蛋白中的胆固醇降低35%,但对VLDL和HDL大小的脂蛋白没有影响。依泽替米贝治疗显著降低了主动脉根部(57%)和冠状动脉(68%)的动脉粥样硬化、心脏肥大(24%)和心脏纤维化(57%),并延长了小鼠的寿命(27%)。这首次证明了依泽替米贝治疗对冠心病的有益作用。用SC-435(0.01%(w/w))对dKO小鼠进行类似治疗,SC-435是一种顶端钠依赖性胆汁酸转运体(ASBT)抑制剂,可阻断胆汁酸的肠道吸收,降低动物血浆胆固醇,并减少apoE KO小鼠的主动脉根部动脉粥样硬化。SC-435治疗的效果与依泽替米贝相似:ILD/LDL大小脂蛋白胆固醇降低37%,中位寿命延长57%。因此,抑制肠道对胆固醇(依泽替米贝)或胆汁酸(SC-435)的吸收可显著降低血浆IDL/LDL大小脂蛋白胆固醇水平,并提高SR-BI/apoE dKO小鼠的存活率。动脉粥样硬化闭塞性动脉冠心病的SR-BI/apoE dKO小鼠模型似乎为评估调节胆固醇稳态和动脉粥样硬化的化合物提供了一个有用的系统。