Cheung M C, Wolfbauer G, Albers J J
Northwest Lipid Research Laboratories, Department of Medicine, School of Medicine, University of Washington, Seattle 98103, USA.
Biochim Biophys Acta. 1996 Sep 27;1303(2):103-10. doi: 10.1016/0005-2760(96)00082-3.
Human plasma phospholipid transfer protein (PLTP) has been shown to facilitate the transfer of phospholipid from liposomes or isolated very low and low density lipoproteins to high density lipoproteins. Its activity in plasma and its physiological function are presently unknown. To elucidate the role of PLTP in lipoprotein metabolism and to delineate factors that may affect the rate of phospholipid transfer between lipoproteins, we determined the plasma phospholipid mass transfer rate (PLTR) in 16 healthy adult volunteers and assessed its relationship to plasma lipid levels, and to phospholipid transfer activity (PLTA) and cholesteryl ester transfer activity (CETA) measured by radioassays. The plasma PLTR in these subjects was 27.2 +/- 11.8 nmol/ml per h at 37 degrees C (mean +/- S.D.), and their PLTA and CETA were 13.0 +/- 1.7 mumol/ml per h and 72.8 +/- 15.7 nmol/ml per h, respectively. Plasma PLTR was correlated directly with total, non-HDL, and HDL triglyceride (rs = 0.76, P < 0.001), total and non-HDL phospholipid (rs > 0.53, P < 0.05), and inversely with HDL free cholesterol (rs = -0.54, P < 0.05), but not with plasma PLTA and CETA. When 85% to 96% of the PLTA in plasma was removed by polyclonal antibodies against recombinant human PLTP, phospholipid mass transfer from VLDL and LDL to HDL was reduced by 50% to 72%, but 80% to 100% of CETA could still be detected. These studies demonstrate that PLTP plays a major role in facilitating the transfer of phospholipid between lipoproteins, and suggest that triglyceride is a significant modulator of intravascular phospholipid transport. Furthermore, most of the PLTP and CETP in human plasma is associated with different particles. Plasma PLTA and CETA were also measured in mouse, rat, hamster, guinea pig, rabbit, dog, pig, and monkey. Compared to human, PLTA in rat and mouse was significantly higher and in rabbit and guinea pig was significantly lower while the remaining animal species had PLTA similar to humans. No correlation between PLTA and CETA was observed among animal species.
人血浆磷脂转运蛋白（PLTP）已被证明可促进磷脂从脂质体或分离出的极低密度脂蛋白和低密度脂蛋白向高密度脂蛋白的转移。其在血浆中的活性及其生理功能目前尚不清楚。为了阐明PLTP在脂蛋白代谢中的作用，并确定可能影响脂蛋白间磷脂转移速率的因素，我们测定了16名健康成年志愿者的血浆磷脂质量转移率（PLTR），并评估了其与血浆脂质水平、通过放射性测定法测得的磷脂转移活性（PLTA）和胆固醇酯转移活性（CETA）之间的关系。这些受试者在37℃时的血浆PLTR为每小时27.2±11.8 nmol/ml（平均值±标准差），其PLTA和CETA分别为每小时13.0±1.7 μmol/ml和每小时72.8±15.7 nmol/ml。血浆PLTR与总甘油三酯、非高密度脂蛋白甘油三酯和高密度脂蛋白甘油三酯直接相关（rs = 0.76，P < 0.001），与总磷脂和非高密度脂蛋白磷脂直接相关（rs > 0.53，P < 0.05），与高密度脂蛋白游离胆固醇呈负相关（rs = -0.54，P < 0.05），但与血浆PLTA和CETA无关。当用抗重组人PLTP的多克隆抗体去除血浆中85%至96%的PLTA时，从极低密度脂蛋白和低密度脂蛋白到高密度脂蛋白的磷脂质量转移减少了50%至72%，但仍能检测到80%至100%的CETA。这些研究表明，PLTP在促进脂蛋白间磷脂转移中起主要作用，并提示甘油三酯是血管内磷脂转运的重要调节因子。此外，人血浆中的大多数PLTP和CETP与不同的颗粒相关。还测定了小鼠、大鼠、仓鼠、豚鼠、兔子、狗、猪和猴子的血浆PLTA和CETA。与人类相比，大鼠和小鼠的PLTA显著更高，兔子和豚鼠的PLTA显著更低，而其余动物物种的PLTA与人类相似。在动物物种之间未观察到PLTA和CETA之间的相关性。
