Abstract 414: In Hyperalphalipoproteinemic Subjects, the Presence of Coronary Artery Disease is Associated With Marked Changes in the High-Density Lipoprotein Phosphosphingolipidome
Plasma concentrations of HDL-C have long been shown to correlate inversely with risk of coronary artery disease (CAD), however the causal nature of this association has not been established. Here we examine the chemical composition and phosphoshingolipidome of HDL in a cohort of subjects with premature CAD, despite having HDL levels ≥90th percentile. We hypothesized that HDL from hyperalphalipoproteinemic subjects with CAD would have distinct compositional changes compared to healthy hyperalphalipoproteinemic subjects, which may relate a reduction in HDL functionality and a pro-atherogenic state. Subjects with HDL ≥90th percentile and CAD (HHDL+CAD, n=25) were compared to healthy subjects with HDL ≥90th percentile (HHDL, n=23). A group of healthy controls with HDL between the 25th and 75th percentile (n=11) was used as reference. HDL subfractions were isolated from EDTA plasma using isopycnic density gradient ultracentrifugation and their chemical composition was assayed using commercial enzymatic assay kits. Quantification of >160 molecular species of total HDL phospho- and sphingolipids was accomplished via a novel method using LC-ESI/MS/MS analysis. The most striking differences were observed in total HDL phospho- and sphingolipid subclasses between groups. When expressed as a percentage of total phosphosphingolipid, phosphatidylcholine (PC) and phosphatidylinositol (PI) were depleted in HHDL+CAD group compared to HHDL, while sphingomyelin (SM) was increased, resulting in a lower PC/SM ratio. The HDL PC/SM ratio has previously been shown to correlate with HDL surface fluidity and antioxidative activity. Additionally, enrichment of PI, a minor, negatively charged phospholipid, has been shown to stimulate cholesterol efflux to reconstituted HDL. Reduction in these two metrics, observed in the HHDL+CAD group, may indicate functionally deficient HDL and may represent pro-atherogenic, HDL-associated biomarkers of CAD in hyperalphalipoproteinemia.
Author Disclosures: W. Hancock-Cerutti: None. M. Lhomme: None. C. Dauteuille: None. S. Lecocq: None. J. Chapman: None. D. Rader: None. A. Kontush: None. M. Cuchel: None.
- © 2014 by American Heart Association, Inc.