Tall A, Sammett D, Granot E
J Clin Invest. 1986 Apr;77(4):1163-72. doi: 10.1172/JCI112417.
In vitro lipoprotein lipase enhances the cholesteryl ester transfer protein (CETP)-mediated transfer of cholesteryl esters from high density lipoproteins (HDL) to very low density lipoproteins as a result of lipolysis-induced alterations in lipoprotein lipids that lead to increased binding of CETP. To determine if there are similar changes during alimentary lipemia, we measured the transfer of cholesteryl esters from HDL to apo B-containing lipoproteins in incubated fasting and postprandial plasma. In seven normolipidemic subjects there was 2-3-fold stimulation of cholesteryl ester transfer in alimentary lipemic plasma. Cholesteryl ester transfer was stimulated when either the d less than 1.063-or d greater than 1.063-g/ml fraction of lipemic plasma was recombined with its complementary fraction of fasting plasma. To determine the distribution of CETP, plasma was fractionated by agarose chromatography and CETP activity was measured in column fractions in a standardized assay. In fasting plasma, most of the CETP was in smaller HDL, and a variable fraction was nonlipoprotein bound. During lipemia there was increased binding of CETP to larger phospholipid-enriched HDL and in two subjects an increase in CETP in apo B-containing lipoproteins. The total CETP activity of fractions of lipemic plasma was increased 1.1-1.7-fold compared with fasting plasma. Lipemic CETP activity was also increased when measured in lipoprotein-free fractions after dissociation of CETP from the lipoproteins. When purified CETP was incubated with phospholipid-enriched HDL isolated from alimentary lipemic or phospholipid vesicle-treated plasma, there was increased binding of CETP to the phospholipid-enriched HDL compared with fasting HDL, with a parallel stimulation in CETP activity. Thus, the pronounced stimulation of cholesteryl ester transfer during alimentary lipemia is due to (a) an increased mass of triglyceride-rich acceptor lipoproteins, (b) a redistribution of CETP, especially increased binding to larger phospholipid-enriched HDL, and (c) an increase in total activity of CETP, perhaps due to an increased CETP mass.
体外脂蛋白脂肪酶可增强胆固醇酯转运蛋白（CETP）介导的胆固醇酯从高密度脂蛋白（HDL）向极低密度脂蛋白的转运，这是脂解诱导的脂蛋白脂质改变导致CETP结合增加的结果。为了确定在饮食性血脂异常期间是否存在类似变化，我们测量了在空腹和餐后血浆孵育过程中胆固醇酯从HDL向含载脂蛋白B的脂蛋白的转运。在7名血脂正常的受试者中，饮食性血脂异常血浆中的胆固醇酯转运受到2至3倍的刺激。当血脂异常血浆中密度小于1.063或大于1.063 g/ml的部分与空腹血浆的互补部分重新组合时，胆固醇酯转运受到刺激。为了确定CETP的分布，通过琼脂糖色谱法对血浆进行分级分离，并在标准化测定中测量柱级分中的CETP活性。在空腹血浆中，大部分CETP存在于较小的HDL中，且有可变部分与非脂蛋白结合。在血脂异常期间，CETP与较大的富含磷脂的HDL的结合增加，并且在两名受试者中，含载脂蛋白B的脂蛋白中的CETP增加。与空腹血浆相比，血脂异常血浆级分的总CETP活性增加了1.1至1.7倍。当在CETP与脂蛋白解离后的无脂蛋白级分中测量时，血脂异常的CETP活性也增加。当将纯化的CETP与从饮食性血脂异常或磷脂囊泡处理的血浆中分离的富含磷脂的HDL一起孵育时，与空腹HDL相比，CETP与富含磷脂的HDL的结合增加，同时CETP活性受到平行刺激。因此，饮食性血脂异常期间胆固醇酯转运的显著刺激是由于：（a）富含甘油三酯的受体脂蛋白质量增加；（b）CETP的重新分布，特别是与较大的富含磷脂的HDL的结合增加；以及（c）CETP总活性增加，可能是由于CETP质量增加。
