Yee Michael S, Pavitt Darrell V, Tan Tira, Venkatesan Soundararajan, Godsland Ian F, Richmond William, Johnston Desmond G
Section of Endocrinology and Metabolic Medicine, Faculty of Medicine, Imperial College London, St Mary's Hospital, London W2 1NY, United Kingdom.
J Lipid Res. 2008 Jun;49(6):1364-71. doi: 10.1194/jlr.D700044-JLR200. Epub 2008 Mar 12.
Separation of lipoproteins by traditional sequential salt density floatation is a prolonged process ( approximately 72 h) with variable recovery, whereas iodixanol-based, self-generating density gradients provide a rapid ( approximately 4 h) alternative. A novel, three-layered iodixanol gradient was evaluated for its ability to separate lipoprotein fractions in 63 subjects with varying degrees of dyslipidemia. Lipoprotein cholesterol, triglycerides, and apolipoproteins were measured in 21 successive iodixanol density fractions. Iodixanol fractionation was compared with sequential floatation ultracentrifugation. Iodixanol gradient formation showed a coefficient of variation of 0.29% and total lipid recovery from the gradient of 95.4% for cholesterol and 84.7% for triglyceride. Recoveries for VLDL-, LDL-, and HDL-cholesterol, triglycerides, and apolipoproteins were approximately 10% higher with iodixanol compared with sequential floatation. The iodixanol gradient effectively discriminated classic lipoproteins and their subfractions, and there was evidence for improved resolution of lipoproteins with the iodixanol gradient. LDL particles subfractionated by the gradient showed good correlation between density and particle size with small, dense LDL (<25.5 nm) separated in fractions with density >1.028 g/dl. The new iodixanol density gradient enabled rapid separation with improved resolution and recovery of all lipoproteins and their subfractions, providing important information with regard to LDL phenotype from a single centrifugation step with minimal in-vitro modification of lipoproteins.
通过传统的连续盐密度浮选法分离脂蛋白是一个漫长的过程（约72小时），回收率也不稳定，而基于碘克沙醇的自生成密度梯度法提供了一种快速（约4小时）的替代方法。我们评估了一种新型的三层碘克沙醇梯度在63名不同程度血脂异常患者中分离脂蛋白组分的能力。在21个连续的碘克沙醇密度组分中测量了脂蛋白胆固醇、甘油三酯和载脂蛋白。将碘克沙醇分级分离法与连续浮选超速离心法进行了比较。碘克沙醇梯度形成的变异系数为0.29%，梯度中胆固醇的总脂质回收率为95.4%，甘油三酯为84.7%。与连续浮选相比，碘克沙醇对极低密度脂蛋白（VLDL）、低密度脂蛋白（LDL）和高密度脂蛋白（HDL）胆固醇、甘油三酯和载脂蛋白的回收率高出约10%。碘克沙醇梯度有效地区分了经典脂蛋白及其亚组分，并且有证据表明碘克沙醇梯度提高了脂蛋白的分辨率。通过该梯度分级分离的LDL颗粒在密度和粒径之间显示出良好的相关性，密度>1.028 g/dl的组分中分离出小而密的LDL（<25.5 nm）。这种新型的碘克沙醇密度梯度能够快速分离，提高所有脂蛋白及其亚组分的分辨率和回收率，通过单次离心步骤提供有关LDL表型的重要信息，且对脂蛋白的体外修饰最小。
