The method for determination of serum lipid-free apolipoprotein concentration and its clinical application

已知HDL在颗粒大小上是不均匀的，并且小HDL颗粒比大HDL颗粒更有效地促进胆固醇从细胞膜流出。小分子HDL的检测采用双向凝胶电泳法，但该方法耗时较长。本研究采用高效液相色谱法分离载脂蛋白A-I，洗脱时间为51 ~ 56 min，由于在ELISA系统中使用了载脂蛋白A-I的抗体，因此，载脂蛋白A-I的表位与HDL的表位相同。我们将50 U/ml的trasyrol加入血液中，并通过HPLC加入500 μ1的分级溶液中。反复冻融实验可使血清载脂蛋白A-I浓度增加2倍，即使在4℃冻存条件下，血清载脂蛋白A-I浓度也随时间变化。因此，血清样品立即进行HPLC处理或在-80℃下冷冻备用。与健康对照组相比，男性和女性冠心病患者的血清无脂质apo A-I浓度显著增加。这些发现表明，胆固醇逆向转运在冠心病中改变，无脂质载脂蛋白A-I的测量可能是动脉粥样硬化的良好标志物。

It is known that HDL are heterogeneous in particle size and small HDL particle can promote more effectively cholesterol efflux from cell membrane than large HDL particle. Small HDL are detected by two-dimentional gel electrophoresis, but this method is time consuming. Lipid-free apo A-I in this study was separated by HPLC and was elutred from 51 min to 56 min. The epitope of lipid-free apo A-I is the same as tjhat of a HDL, because we used the antibody to apo A-I in the ELISA system. We added SOU/ml of trasyrol to blood and also to 500 μ1 of fractionated solutions by HPLC. Serum lipid-free apo A-I concentration increased two times by repeated freeze and thawing test and changed with time even in the store at 4℃. Thus, serum sample was immediately treated for HPLC or freezed at -80℃ until use.Serum lipid-free apo A-I concentrations significantly increased in patients with coronary heart disease compared to healthy controls in both males and females. These findings show that reverse cholesterol transport is altered in coronary heat disease and the measurement of lipid-free apo A-I may be a good marker for atherosclerosis.