Abstract 534: High-density Lipoprotein Particles Containing Lipids Bearing An Eicosapentaenoyl Moiety Exhibit Increased Rates Of HDL-apolipoprotein A-I Exchange

Abstract

Objective: Eicosapentaenoic acid (EPA) is a polyunsaturated fatty acid associated with cardiovascular risk reduction and found in fatty fish, dietary supplements, and more recently, prescription drugs. EPA is incorporated into phospholipids which are transported through the body by lipoproteins, including high-density lipoprotein (HDL). HDL function can be measured from the HDL-apolipoprotein (apoA-I) exchange rate. We measured the rate of HDL-apoA-I exchange (HAE) on reconstituted HDL particles containing phospholipids bearing an eicosapentanoyl moiety to examine whether EPA is associated with enhanced HDL function. Method and Results: Reconstituted HDL particles were synthesized using recombinant human apoA-I. EPA-containing HDL particles were made with 16:0-20:5n-3 phosphocholine (PC) and 16:0-18:1n-9 PC in an 8:72 and 16:64 molar ratio, respectively. Particles containing only 16:0-18:1n-9 PC were used as a control. HDL particles were incubated with lipid-free apoA-I labeled with an Alexa 488 fluorophore as a probe to initiate HAE. The extent of HAE over time was quantified by non-denaturing gradient gel electrophoresis to separate HDL particles from lipid-free apoA-I. The extent of Alexa 488 apoA-I binding to HDL was determined using densitometry. HDL particles containing EPA lipids exhibited 2-fold (8:72) and 2.5-fold (16:64) higher rates of HAE relative to the control particles. Conclusions: HDL particles containing EPA lipids show increased rates of HAE. The effect is dose-dependent, suggesting that among its benefits, EPA improves HDL function.