Abstract 361: Characterization of Lipoproteins in the Hypertriglyceridemic Fredrickson-Levy Dyslipidemic Phenotypes with Chylomicrons: The Very Large Database of Lipids (VLDL-7)

Abstract

Background The major dyslipidemia (DL) classes (I-V) are relatively rare with limited phenotypic characterization across large populations. Methods We studied 1,340,614 U.S. adults from the Very Large Database of Lipids and identified those with chylomicron (CM) excess (types I and V). Lipid testing was by ultracentrifugation (VAP, Atherotech, Birmingham, AL). The distributions of total cholesterol (TC), HDL-C, LDL-C and triglycerides (TG) in the database were superimposable with those in the NHANES 2007-2008 survey. We used the following criteria to classify the excess lipoprotein components of DL in subjects with TG >130 mg/dL: CM defined by TG/Total cholesterol (TC) ratio > 9 only (Type I) and CM with >90th percentile VLDL-C (Type V). Subjects with types II, III, or IV DL were excluded. Results Type I DL was characterized by very high TG and very low HDL-C, LDLr-C, non-HDL-C and normal VLDL-C and RLP-C. Type V was characterized by TG approximately twice that of type I, low HDL-C and LDLr-C, and elevated VLDL-C, RLP-C and non-HDL-C. The VLDL3-C/IDL-C ratio was approximately 2, twice that of the non-CM groups (Table). Summary To our knowledge, this is the largest single report of subjects with these rare hyper-CM phenotypes. The findings support the mechanism of reduced CM clearance and impaired conversion of VLDL to IDL and LDL. The marked reduction in HDL-C is consistent with cholesterol ester transport protein mediated TG-Cholesterol ester exchange between CM and apoB100 lipoproteins.