Background: High-density lipoprotein (HDL) containing apolipoprotein E (apoE-rich HDL) represents only a small portion of plasma HDL. Reliable methods for determining and isolating apoE-rich HDL have not been well studied.
Methods: We established a novel analytical method for apoE-rich HDL using polyethylene glycol and a cation-exchange column (PEG-column method). Furthermore, we examined biochemical correlates of apoE-rich HDL-cholesterol (HDL-C) in 36 patients who underwent coronary computed tomographic angiography.
Results: Our PEG-column method demonstrated high reproducibility (coefficient of variation <3.52%) and linearity up to 15 mg/dl for apoE-rich HDL-C concentrations. Isolated apoE-rich HDL exhibited a larger diameter (14.8 nm) than apoE-poor HDL (10.8 nm) and contained both apoE and apoA-I. ApoE-rich HDL-C concentrations correlated significantly with triglycerides (r(s) = -0.646), LDL size (r(s) = 0.472), adiponectin (r(s) = 0.476), and other lipoprotein components. No significant correlation was obtained with the coronary calcium score. Multiple regression analysis revealed that plasma triglycerides and adiponectin concentrations remained significant independent predictors of apoE-rich (adjusted R-2 = 0.486) but not apoE-poor HDL-C.
Conclusions: The PEG-column method demonstrated, to various degrees, significant correlations between HDL subtractions and several lipid-related biomarkers involved in an atherogenic lipoprotein profile. Our separation technique for apoE-rich HDL is useful to clarify the role of apoE-rich HDL in atherosclerosis. (C) 2016 Elsevier B.V. All rights reserved.