Ouguerram K, Krempf M, Maugeais C, Maugère P, Darmaun D, Magot T
Centre de Recherche en Nutrition Humaine, INSERM U539, Nantes, France.
Metabolism. 2002 Jan;51(1):5-11. doi: 10.1053/meta.2002.29006.
A method to study reverse cholesterol transport in humans was developed using stable isotopes and kinetic analysis. Three normolipidemic subjects received simultaneous intravenous infusions of deuterated leucine and (13)C-acetate for 14 and 8 hours, respectively. Deuterium enrichment was measured in protein-bound leucine in apolipoproteins (apo) B-100 and A-I (using gas chromatography coupled with mass spectrometry [GCMS]) and (13)C-enrichment in unesterified cholesterol and cholesteryl ester (using gas chromatography coupled to isotope ratio mass spectrometry [GC-C-IRMS]) in very-low-density lipoprotein (VLDL), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) during the tracer infusion. Curves were analyzed using multicompartmental analysis. This protocol is suitable to quantify the different processes involved in reverse cholesterol transport (RCT) in humans, including cholesterol esterification, transfer of cholesteryl ester from HDL towards apo B-100-containing lipoproteins, and the contribution of VLDL, LDL, and HDL in the final steps of RCT. In agreement with previous data from kinetic analysis of radiotracer experiments, our results suggest that in fasting normolipidemic subjects the major fraction of cholesteryl ester enters plasma through esterification in HDL (more than 95%). The major fraction of cholesteryl ester disappears through apo B-100-containing lipoproteins (VLDL and LDL) catabolism (mean of 82%) rather than through removal from HDL (mean of 18% with approximately an equal part for apo AI-dependent and independent catabolism, respectively, 7% and 11%). We conclude that this protocol could be applied to study the modulation of these processes by nutrition, diseases, or pharmacologic treatments.
利用稳定同位素和动力学分析开发了一种研究人体逆向胆固醇转运的方法。三名血脂正常的受试者分别接受了14小时和8小时的氘代亮氨酸和（13）C-乙酸盐静脉输注。在示踪剂输注期间，使用气相色谱-质谱联用（GCMS）测量载脂蛋白（apo）B-100和A-I中与蛋白质结合的亮氨酸中的氘富集，以及使用气相色谱-同位素比值质谱联用（GC-C-IRMS）测量极低密度脂蛋白（VLDL）、低密度脂蛋白（LDL）和高密度脂蛋白（HDL）中未酯化胆固醇和胆固醇酯中的（13）C富集。使用多室分析对曲线进行分析。该方案适用于量化人体逆向胆固醇转运（RCT）中涉及的不同过程，包括胆固醇酯化、胆固醇酯从HDL向含apo B-100的脂蛋白的转移，以及VLDL、LDL和HDL在RCT最后步骤中的作用。与先前放射性示踪剂实验的动力学分析数据一致，我们的结果表明，在空腹血脂正常的受试者中，胆固醇酯的主要部分通过HDL中的酯化进入血浆（超过95%）。胆固醇酯的主要部分通过含apo B-100的脂蛋白（VLDL和LDL）分解代谢消失（平均82%），而不是通过从HDL中清除（平均18%，apo AI依赖性和非依赖性分解代谢各占约相等部分，分别为7%和11%）。我们得出结论，该方案可用于研究营养、疾病或药物治疗对这些过程的调节作用。
