LOW DENSITY LIPOPROTEIN (LDL) METABOLISM IN PRIMATE ATHEROSCLEROSIS

灵长类动物动脉粥样硬化中的低密度脂蛋白 (LDL) 代谢

• 批准号: 6338875
• 负责人: Lawrence L Rudel
• 金额: $ 19.92万
• 依托单位: WAKE FOREST UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-01 至 2001-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6338875
• 关键词: Cercopithecidae; acetyl coA acetyltransferase; atherosclerosis; blood lipoprotein metabolism; cholesterol; coronary disorder; dietary lipid; disease /disorder model; genetically modified animals; laboratory mouse; liver cells; liver metabolism; low density lipoprotein; low density lipoprotein receptor; nutrition related tag; pathogenic diet; proteoglycan; receptor binding; saturated fatty acids; steroid 7alpha hydroxylase; tissue /cell culture; unsaturated fatty acids

This observation was made in the last funding period that mono-unsaturated fat did not protect against coronary artery atherosclerosis in spite of an improved LDL/HDL ration. Due to the public health significance of this observation, we propose to confirm and extend this observation with further studies, while attempting to define mechanisms through which the outcome occurs. Groups of African green monkeys will be fed four different dietary fats (saturated, mono-unsaturated, and n-6 and n-3 polyunsaturated) to modify LDL particle composition. Plasma LDL cholesterol concentrations will be balanced among dietary fat groups so that the effect of LDL composition on the extend of coronary artery atherosclerosis can be assessed directly. The spectrum of plasma lipoprotein responses will be measured in each of the animals in the study, and the extend of coronary artery atherosclerosis that develops over a four year period of diet-induction will also be measured so that any lipoprotein-atherosclerosis relationship, and dietary fatty acid effect thereon, can be identified. The main hypothesis to be tested in this proposal is that compositionally modified, cholesteryl oleate enriched low density lipoproteins promote atherosclerosis out of proportion of their number through a predisposition to promote cholesterol accumulation in the coronary arteries. To examine how compositionally modified LDL could promote atherogenesis, LDL from each diet group will be examined for their binding to arterial proteoglycans (PG) and effects on PG production by arterial smooth muscle cells. Substitution of dietary n-3 polyunsaturated fatty acids into the diet results in less cholesteryl oleate accumulation and secretion by liver, as well as an increased cholesterol 7alpha-hydroxylase (C7H) activity and reduced free cholesterol content of liver. The two liver cholesterol -metabolizing enzymes, acyl- CoA: cholesterol acyltransferase (ACAT) and C7H appear to be key regulatory sites for determining cholesterol balance across the liver. Study of the regulation of hepatic ACAT(s) and C7H will be carried out in sequential liver biopsies taken from monkeys fed different diets, and that in isolated monkey hepatocytes incubated with varying fatty acid types and cholesterol concentrations, and during isolated liver perfusion with livers isolated from animals from each of the different diet groups. Evidence is accumulating that there are multiple ACAT enzymes in liver, and we will identify and characterize the hepatic ACAT(s) to be sure that regulation of the pertinent enzyme is document. Finally, we propose to examine a transgenic mouse with very high LDL cholesterol levels a model in which to test the dietary fatty acid effects on LDL composition and atherosclerosis, since genetic modifications in ACAT and/or C7H, for example can eventually be tested in mice.

这一观察结果是在最后一个融资期间进行的 尽管有 改进的LDL/HDL定量。由于公共卫生的意义 观察，我们建议确认并扩展此观察 进一步的研究，同时尝试定义机制 结果发生。非洲绿猴子将被喂四个不同 饮食脂肪（饱和，单饱和，N-6和N-3 多不饱和）修改LDL颗粒组成。血浆LDL 胆固醇浓度将在饮食脂肪群中平衡，因此 LDL成分对冠状动脉延伸的影响 动脉粥样硬化可以直接评估。等离子体的光谱 将在每种动物中测量脂蛋白反应 研究以及发展的冠状动脉动脉粥样硬化的延伸 在四年的饮食诱导期内，也将衡量 任何脂蛋白 - 阿瑟肠细胞化关系和饮食脂肪酸 效果可以识别。要测试的主要假设 该提议是构图修改的胆汁胆汁 富集的低密度脂蛋白从中促进动脉粥样硬化 通过促进胆固醇的易感性的比例 冠状动脉的积累。检查构图如何 改良的LDL可以促进动脉粥样硬化，每个饮食组的LDL将是 检查了它们与动脉蛋白聚糖（PG）的结合以及对 动脉平滑肌细胞产生PG。饮食N-3的替代 饮食中的多不饱和脂肪酸导致胆固醇较少 肝脏的积累和分泌，以及增加 胆固醇7alpha-羟化酶（C7H）活性和降低游离胆固醇 肝脏的含量。两种肝胆固醇代谢酶，酰基 - COA：胆固醇酰基转移酶（ACAT）和C7H似乎是关键 调节位点，用于确定整个肝脏的胆固醇平衡。 将研究肝ACAT和C7H的调节 从喂不同饮食的猴子中取的顺序肝活检， 在孤立的猴子肝细胞中，与不同的脂肪酸类型孵育 胆固醇浓度，在孤立的肝灌注期间 从每个不同饮食组中分离出的动物的肝脏。 有证据表明肝脏中有多种ACAT酶， 我们将确定并描述肝脏ACAT，以确保 相关酶的调节是文件。最后，我们建议 检查具有非常高的LDL胆固醇水平的转基因小鼠模型 在其中测试饮食脂肪酸对LDL组成和 动脉粥样硬化，因为ACAT和/或C7H的遗传修饰，用于 示例最终可以在小鼠中进行测试。