Apolipoprotein B-bound lipids as a marker for evaluation of low density lipoprotein oxidation in vivo.
Apolipoprotein B-bound lipids as a marker for evaluation of low density lipoprotein oxidation in vivo.
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载脂蛋白 B 结合脂质作为评估体内低密度脂蛋白氧化的标志物。
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
A. Orekhov
中科院分区：
文献类型：
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作者：
V. Tertov;V. Kaplun;S. N. Dvoryantsev;A. Orekhov
人们普遍认为氧化低密度脂蛋白（LDL）在动脉粥样硬化形成中起着重要作用。然而，在患者血液中未检测到氧化的低密度脂蛋白，并且体内低密度脂蛋白氧化的程度尚不清楚。我们认为LDL氧化可能导致脂质和载脂蛋白B之间形成共价连接。LDL被铜离子、2,2'-偶氮双-(2-氨基丙烷盐酸盐)、次氯酸钠或通过与巨噬细胞一起孵育而氧化。氧化的低密度脂蛋白通过用有机溶剂反复萃取来脱脂。温和碱性水解后，通过比色法和高效液相色谱法鉴定蛋白质结合的甾醇。通过核磁共振和比色测定磷酸盐来检测蛋白质结合的磷脂残基。使用放射性标记的脂质还表明，游离和酯化的胆固醇、磷脂以及甘油三酯和游离脂肪酸残基可以与载脂蛋白 B 形成共价键。脂质与载脂蛋白 B 结合的能力与其脂肪酸的不饱和程度相关，并且取决于磷脂极性头的性质。当低密度脂蛋白被铜离子氧化时，蛋白结合脂质的含量在孵育24小时内逐渐增加，而共轭二烯、氢过氧化物和硫代巴比妥酸反应物质的水平发生不同程度的变化。研究表明，冠状动脉粥样硬化患者的多重修饰去唾液酸化低密度脂蛋白中蛋白结合甾醇的含量高于天然低密度脂蛋白。我们的结果表明，蛋白质结合脂质的水平可能是 LDL 氧化的标志，可用于评估脂蛋白氧化与动脉粥样硬化形成的关联。
It has been generally accepted that oxidized low density lipoprotein (LDL) plays an important role in atherogenesis. However, oxidized LDL was not detected in patients' blood and the extent of LDL oxidation in vivo is unknown. We have suggested that LDL oxidation may lead to a formation of covalent links between lipids and apolipoprotein B. LDL were oxidized by copper ions, 2,2'-azobis-(2-aminopropane hydrochloride), sodium hypochlorite or by incubation with macrophages. Oxidized LDL were delipidated by repeated extraction with organic solvents. After mild alkaline hydrolysis protein-bound sterols were identified colorimetrically and by high-performance liquid chromatography. Protein-bound phospholipid residues were detected by nuclear magnetic resonance and colorimetric determination of phosphate. Using radiolabeled lipids it was also shown that free and esterified cholesterol, phospholipids, as well as triglyceride and free fatty acid residues can form covalent bonds with apolipoprotein B. The ability of lipids to bind to apolipoprotein B correlates with the degree of unsaturation of their fatty acids and depends on the nature of polar head of phospholipids. When LDL were oxidized with copper ions, the content of protein-bound lipids increased gradually up to 24 h of incubation, while the levels of conjugated dienes, hydroperoxides and thiobarbituric acid-reactive substances changed in varying manners. It has been demonstrated that the content of protein-bound sterols in multiple-modified desialylated LDL of patients with coronary atherosclerosis is higher than that in native LDL. Our results suggest that the level of protein-bound lipids may be a marker of LDL oxidation and can be used to evaluate the association of lipoprotein oxidation and atherogenesis.