ABCG5 ABCG8-independent mechanisms fail to maintain sterol balance in mice fed a high cholesterol diet.

The ABCG5 ABCG8 (G5G8) sterol transporter opposes the accumulation of dietary xenosterols, but is also the primary mediator of biliary cholesterol secretion in the cholesterol elimination pathway. In humans and in mouse models of disrupted biliary cholesterol secretion, fecal neutral sterols remain constant, indicating the presence of a G5G8-independent mechanism for cholesterol excretion. Transintestinal cholesterol elimination (TICE) is thought to compensate for biliary G5G8 insufficiency.

Hepatic Inactivation of Carnitine Palmitoyltransferase 1a Lowers Apolipoprotein B Containing Lipoproteins in Mice.

Unlabelled: Genome- and epigenome-wide association studies have associated variants and methylation status of carnitine palmitoyltransferase 1a (CPT1a) to reductions in very low-density lipoprotein (VLDL) cholesterol and triglyceride levels. We report significant associations between the presence of SNPs and reductions in plasma cholesterol, as well as positive associations between hepatic Cpt1a expression and plasma cholesterol levels across inbred mouse strains. Mechanistic studies show that both wild type and human apolipoprotein B100 (apoB)-transgenic mice with liver-specific deletion of (LKO) display lower circulating apoB levels consistent with reduced LDL-cholesterol (LDL-C) and LDL particle number.

Enhancement of high-density lipoprotein-associated protease inhibitor activity prevents atherosclerosis progression.

Background And Aims: Inflammatory cells within atherosclerotic lesions secrete proteolytic enzymes that contribute to lesion progression and destabilization, increasing the risk for an acute cardiovascular event. Elastase is a serine protease, secreted by macrophages and neutrophils, that may contribute to the development of unstable plaque. We previously reported interaction of endogenous protease-inhibitor proteins with high-density lipoprotein (HDL), including alpha-1-antitrypsin, an inhibitor of elastase.