Abstract 11987: Lipoprotein Particle Number Analysis of Detailed Subclasses by Gel Permeation HPLC.

High HDL-cholesterol (HDL-C) levels and low LDL-cholesterol (LDL-C) levels are negatively correlated with cardiovascular diseases (CVD). However, these lipid parameters are not enough to represent the physiological functions or properties of lipoproteins, which are heterogeneous particles. Recent reports even have shown that extremely high HDL-C levels have an adverse effect on CVD mortality. To better understand the association of lipoproteins with CVD, detailed characterization of lipoproteins would be needed beyond HDL-C or LDL-C levels. We have recently established an analytical method by gel permeation HPLC (GP-HPLC) system (LipoSEARCH®) to evaluate lipoprotein particle numbers (PNs) of detailed subclasses, which consist of 3 VLDL (large, medium, small), 4 LDL (large, medium, small, very small), and 5 HDL (very large, large, medium, small, very small) subclasses. This method can calculate PNs of each subclass more precisely than proton nuclear magnetic resonance spectrometry or ion mobility methods, which are most widely used for measuring PNs (J Oleo Sci 65:265-282, 2016). Using this method, we investigated lipoprotein PNs in normolipidemic healthy subjects (n=9) and homozygous cholesteryl ester transfer protein deficient (CETP-D) patients (n=9), who are not likely to be protected from CVD despite high HDL-C and low LDL-C levels. The PNs of very large and large HDL in CETP-D were markedly higher than those in healthy subjects (19.9- and 4.5-fold increase, respectively; p<0.001), whereas the PNs of small and very small HDL, which have more potent anti-atherogenic functions, were significantly lower (0.76- and 0.61-fold decrease, respectively; p<0.001). Furthermore, interestingly, the PN of very small LDL, which is known to be atherogenic, was significantly higher in CETP-D (1.36-fold increase, p=0.016). Thus, this novel method by GP-HPLC can provide detailed lipoprotein characterization. [ABSTRACT FROM AUTHOR]