Kontush A, Spranger T, Reich A, Djahansouzi S, Karten B, Braesen J H, Finckh B, Kohlschütter A, Beisiegel U
Medical Clinic, Universitätskrankenhaus Eppendorf, Hamburg, Germany.
Biofactors. 1997;6(2):99-109. doi: 10.1002/biof.5520060203.
Lipoprotein oxidation induced in vitro in whole plasma is expected to be a more relevant model of the lipoprotein oxidation in the arterial wall than the in vitro oxidation of single isolated lipoproteins, e.g., low density lipoprotein (LDL). However, it is unclear, whether the oxidizability of whole plasma may serve as an adequate measure of the oxidizability of plasma lipoproteins. We measured the oxidizability of whole plasma diluted 150-fold as an absorbance increase at 234 nm known to reflect the level of conjugated dienes in the samples. Plasma oxidation was induced by Cu(II), 2,2'-azobis-(2-amidinopropane) hydrochloride (AAPH), lipoxygenase or myeloperoxidase+H2O2. Oxidizability of human plasma measured in the presence of Cu(II) was found to correlate with the oxidizability of LDL measured in the common Cu(II)-based LDL oxidation assay. The plasma oxidizability also correlated positively with plasma oxidizable fatty acid and negatively with plasma antioxidant content. Supplementation of human plasma with different antioxidants (albumin, urate, ascorbate, bilirubin, alpha-tocopherol and ubiquinol-10) in vitro decreased its oxidizability. Supplementation of Watanabe heritable hyperlipidaemic rabbits with different antioxidants (vitamin E, ubiquinone-10, probucol, carvedilol) in vivo lowered the oxidizability of rabbit plasma in comparison with rabbits fed standard diet. When plasma from hyperlipidaemic patients with or without coronary heart disease and from age-matched healthy controls was studied, the plasma oxidizability was found to be highest in the patients with coronary heart disease and lowest in the controls. Taken together, these data indicate that the plasma oxidation assay (i) provides information similar to that obtained using the common LDL oxidation assay, (ii) upgrades the latter, taking into account the effect of hydrophilic antioxidants on lipoprotein oxidation and characterizing the oxidizability of all plasma lipoproteins, and (iii) offers important practical advantages, such as fast and simple sample processing, low amount of plasma required and avoidance of artefactual oxidation during lipoprotein isolation. We propose the measurement of plasma oxidizability at 234 nm as an adequate practical index of the oxidizability of plasma lipoproteins.
与单个分离脂蛋白（如低密度脂蛋白，LDL）的体外氧化相比，全血浆体外诱导的脂蛋白氧化有望成为动脉壁脂蛋白氧化更相关的模型。然而，尚不清楚全血浆的氧化能力是否可作为血浆脂蛋白氧化能力的适当衡量指标。我们将全血浆稀释150倍后测量其氧化能力，以234nm处吸光度的增加来反映，已知该吸光度可反映样品中共轭二烯的水平。血浆氧化由铜（II）、2,2'-偶氮二（2-脒基丙烷）盐酸盐（AAPH）、脂氧合酶或髓过氧化物酶+H₂O₂诱导。发现在铜（II）存在下测量的人血浆氧化能力与在常见的基于铜（II）的LDL氧化试验中测量的LDL氧化能力相关。血浆氧化能力还与血浆中可氧化脂肪酸呈正相关，与血浆抗氧化剂含量呈负相关。体外向人血浆中添加不同的抗氧化剂（白蛋白、尿酸盐、抗坏血酸盐、胆红素、α-生育酚和泛醇-10）可降低其氧化能力。与喂食标准饮食的兔子相比，体内向遗传性高脂血症的渡边兔补充不同的抗氧化剂（维生素E、泛醌-10、普罗布考、卡维地洛）可降低兔血浆的氧化能力。当研究患有或未患有冠心病的高脂血症患者以及年龄匹配的健康对照者的血浆时，发现冠心病患者的血浆氧化能力最高，而对照组最低。综上所述，这些数据表明血浆氧化试验（i）提供了与使用常见LDL氧化试验获得的信息相似的信息，（ii）对后者进行了改进，考虑了亲水性抗氧化剂对脂蛋白氧化的影响并表征了所有血浆脂蛋白的氧化能力，并且（iii）具有重要的实际优势，例如样品处理快速简单、所需血浆量少以及避免脂蛋白分离过程中的人为氧化。我们建议测量234nm处的血浆氧化能力作为血浆脂蛋白氧化能力的适当实用指标。
