Folcik V A, Cathcart M K
Cleveland Clinic Foundation, OH 44194.
J Lipid Res. 1994 Sep;35(9):1570-82.
Low density lipoprotein that was oxidized by activated human monocytes was analyzed to determine the identity of oxidized fatty acids present and the conditions required for their formation. The oxidized lipids were also analyzed under conditions allowing preservation of their oxidation state. Using reversed-phase high performance liquid chromatography (HPLC) analysis of native and saponified lipid extracts of oxidized low density lipoprotein (LDL), we found that the major fatty acid oxidation product was esterified hydroperoxyoctadecadienoic acid (HPODE), the oxidized product of the most abundant polyunsaturated fatty acid in human LDL, linoleic acid. Although some esterified hydroxyoctadecadienoic acid (HODE) was also detected, the reduction of HPODE to HODE did not appear to be monocyte-dependent. Essentially all of the HPODE was found to be esterified with the majority being esterified to cholesterol followed by phospholipids and generally following the abundance of esterified linoleic acid within the lipid classes. The percent of cholesteryl linoleate converted to cholesteryl HPODE and cholesteryl HODE at the end of the 24-h incubation was determined to be approximately 13.5%. The formation of oxidized esterified linoleic acid in the LDL was shown to require immunological activation of the human monocytes, a previously observed requirement for general LDL oxidation in this culture system. The oxidized esterified linoleic acid was present in the supernatant with the LDL and was not cell-associated. HPODE formation on LDL was prevented by including superoxide dismutase (SOD) or eicosatetraynoic acid (ETYA) during the 24-h coincubation of activated monocytes with LDL whereas indomethacin was without effect. The analysis of the lipid oxidation products in oxidized LDL can provide insight into the mechanisms involved in oxidation of LDL by activated human monocytes.
对被活化的人单核细胞氧化的低密度脂蛋白进行分析，以确定所存在的氧化脂肪酸的种类及其形成所需的条件。还在能够保持其氧化状态的条件下对氧化脂质进行了分析。通过对氧化低密度脂蛋白（LDL）的天然脂质提取物和皂化脂质提取物进行反相高效液相色谱（HPLC）分析，我们发现主要的脂肪酸氧化产物是酯化氢过氧化十八碳二烯酸（HPODE），它是人类LDL中最丰富的多不饱和脂肪酸亚油酸的氧化产物。虽然也检测到了一些酯化羟基十八碳二烯酸（HODE），但HPODE还原为HODE似乎并不依赖于单核细胞。基本上所有的HPODE都被酯化，其中大部分与胆固醇酯化，其次是磷脂，并且一般遵循脂质类别中酯化亚油酸的丰度。在24小时孵育结束时，亚油酸胆固醇酯转化为HPODE胆固醇酯和HODE胆固醇酯的百分比约为13.5%。结果表明，LDL中氧化酯化亚油酸的形成需要人单核细胞的免疫激活，这是该培养系统中先前观察到的LDL一般氧化所必需的条件。氧化酯化亚油酸与LDL一起存在于上清液中，不与细胞相关。在活化的单核细胞与LDL共同孵育24小时期间，加入超氧化物歧化酶（SOD）或二十碳四烯酸（ETYA）可防止LDL上HPODE的形成，而吲哚美辛则无效。对氧化LDL中脂质氧化产物的分析可以深入了解活化的人单核细胞氧化LDL的机制。
