Abstract 14972: Association Between CEC Measured by Immobilized Liposome-Bound Gel Beads Method and the Size of Lipid-Rich Coronary Artery Plaque

Abstract

Introduction/Background: High-density lipoprotein (HDL) exerts cholesterol efflux capacity (CEC), and it ameliorates cardiovascular disease (CVD). CEC had been expected as a surrogate biomarker in addition to HDL cholesterol (HDL-C), which has been found not always to reflect the CVD risk. However, the procedures of the conventional CEC assays were too complex to be introduced into clinical practice because of cell-based assay. Given this situation, we invented novel cell-free CEC assay named immobilized liposome-bound gel beads (ILG) method. ILG method utilizes liposomes which contain fluorescence labeled cholesterol instead of lipid loaded foam cells, and has advantage of simplicity of procedure and accuracy. Reserch Question/Hypothesis: Does ILG method show some associations between CEC and HDL subclass, and also reflect the condition of coronary artery plaque? Goals/Aim: We aim to demonstrate CEC by ILG method has clinical significance for assessment of the CVD risk. Methods/Approach: Patients who underwent diagnostic catheterization or percutaneous coronary intervention were enrolled, and 61 patients were examined through CEC analysis by ILG method and assessment of coronary artery plaque by optical coherence tomography (OCT) imaging. Large lipid-rich plaque was defined as a lipid plaque with a lipid arc ≥180°and lipid length ≥5 mm. Serum HDL subclass was analyzed by enzymatic assay (Denka). We defined the ratio apolipoprotein E(apoE)-containing HDL-C to HDL-C as %apoE, and we also calculated the value of HDL 3 -C/HDL 2 -C, and classified HDL 3 - or HDL 2 -rich group. Results/Data: HDL-C was positively associated with %apoE, and CEC of apoE-rich patients was higher than that of apoE-poor patients. This correlation was maintained after classified based on size of HDL. CEC and %apoE in patients with large lipid-rich plaque were significantly lower than in those in without. In contrast, there was no significant difference in HDL-C and LDL-C. Conclusion: In present study, ILG method showed that apoE has some influence on CEC, and CEC was inversely correlated with size of lipid-rich plaque. These results implied that ILG method, suitable CEC assay for clinical site, might be useful to assess the CVD risk.