Wasan K M, Pritchard P H, Ramaswamy M, Wong W, Donnachie E M, Brunner L J
Division of Pharmaceutics and Biopharmaceutics, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada.
Pharm Res. 1997 Nov;14(11):1613-20. doi: 10.1023/a:1012190620854.
The purpose of this study was to define the relationship between lipoprotein (LP) lipid concentration and composition and the distribution of cyclosporine (CSA) in human plasma.
3H-CSA LP distribution was determined in normolipidemic human plasma that had been separated into different LP and lipoprotein-deficient plasma (LPDP) fractions by either affinity chromatography coupled with ultracentrifugation, density gradient ultracentrifugation or fast protein liquid chromatography. 3H-CSA LP distribution (at a concentration of 1000 ng/ml) was also determined in patient plasma samples with defined dyslipidemias. Furthermore, 3H-CSA LP distribution was determined in patient plasma samples of varying LP lipid concentrations. Following incubation, the plasma samples were separated into their LP and LPDP fractions by sequential phosphotungistic acid precipitation in the dyslipidemia studies and by density gradient ultracentrifugation in the specific lipid profile studies and assayed for CSA by radioactivity. Total plasma and lipoprotein cholesterol (TC), triglyceride (TG) and protein (TP) concentrations in each sample were determined by enzymatic assays.
When the LP distribution of CSA was determined using three different LP separation techniques, the percent of CSA recovered in the LP-rich fraction was greater than 90% and the LP binding profiles were similar with most of the drug bound to plasma high-density (HDL) and low-density (LDL) lipoproteins. When 3H-CSA was incubated in dyslipidemic human plasma or specific patient plasma of varying LP lipid concentrations the following relationships were observed. As the very low-density (VLDL) and LDL cholesterol and triglyceride concentrations increased, the percent of CSA recovered within the VLDL and LDL fractions increased. The percent of CSA recovered within the HDL fraction significantly decreased as HDL triglyceride concentrations increased. The percent of CSA recovered in the LPDP fraction remained constant except in hypercholesterolemic/hypertriglyceridemic plasma where the percent of CSA recovered decreased. Furthermore, increases in VLDL and HDL TG/TC ratio resulted in a greater percentage of CSA recovered in VLDL but less in HDL.
These findings suggest that changes in the total and plasma LP lipid concentration and composition influence the LP binding of CSA and may explain differences in the pharmacological activity and toxicity of CSA when administered to patients with different lipid profiles.
本研究旨在确定脂蛋白（LP）脂质浓度和组成与环孢素（CSA）在人血浆中分布之间的关系。
通过亲和色谱结合超速离心、密度梯度超速离心或快速蛋白质液相色谱法，将正常血脂的人血浆分离成不同的LP和脂蛋白缺陷血浆（LPDP）组分，测定3H-CSA在其中的LP分布。还在患有特定血脂异常的患者血浆样本中测定了3H-CSA的LP分布（浓度为1000 ng/ml）。此外，在LP脂质浓度不同的患者血浆样本中测定了3H-CSA的LP分布。孵育后，在血脂异常研究中通过连续磷钨酸沉淀法、在特定脂质谱研究中通过密度梯度超速离心法将血浆样本分离成LP和LPDP组分，并通过放射性测定CSA。通过酶法测定每个样本中的总血浆和脂蛋白胆固醇（TC）、甘油三酯（TG）和蛋白质（TP）浓度。
当使用三种不同的LP分离技术测定CSA的LP分布时，富含LP的组分中回收的CSA百分比大于90%，且LP结合谱相似，大多数药物与血浆高密度（HDL）和低密度（LDL）脂蛋白结合。当3H-CSA在血脂异常的人血浆或LP脂质浓度不同的特定患者血浆中孵育时，观察到以下关系。随着极低密度（VLDL）和LDL胆固醇及甘油三酯浓度的增加，VLDL和LDL组分中回收的CSA百分比增加。随着HDL甘油三酯浓度的增加，HDL组分中回收的CSA百分比显著降低。LPDP组分中回收的CSA百分比保持不变，但在高胆固醇血症/高甘油三酯血症血浆中，回收的CSA百分比降低。此外，VLDL和HDL TG/TC比值的增加导致VLDL中回收的CSA百分比更高，而HDL中更低。
这些发现表明，总血浆和LP脂质浓度及组成的变化会影响CSA与LP的结合，并可能解释在给不同脂质谱的患者使用CSA时其药理活性和毒性的差异。
