To characterize lipoprotein uptake by macrophages, we studied J774 murine macrophage-derived cells. Uptake of 125I-labeled beta-VLDL and 125I-labeled chylomicron remnants was saturable, specific, and of high affinity. Maximal specific uptake and the concentration at which half-maximal uptake occurred were similar for both beta-VLDL and chylomicron remnants. Specific uptake of 125I-labeled chylo...

Lipoprotein lipase (LPL) bound to the lumenal surface of vascular endothelial cells is responsible for the hydrolysis of triglycerides in plasma lipoproteins. Studies were performed to investigate whether human plasma lipoproteins and/or free fatty acids would release LPL which was bound to endothelial cells. Purified bovine milk LPL was incubated with cultured porcine aortic endothelial cells ...

Since the molecular identification of the low density lipoprotein receptor (LDLR), an ever increasing number of related proteins have been discovered. These receptors belonging to the LDLR family are thought to play key roles in lipoprotein metabolism in a variety of tissues, including the arterial wall. We have discovered that the expression of a 250-kDa mosaic LDLR-related protein, which we t...

Low density lipoproteins (LDL) in blood plasma and their immediate precursors are generally thought to be the major atherogenic lipoproteins. The initial indications that LDL are formed from very low density lipoproteins (VLDL) were obtained more than 25 years ago (1, 2), yet even today the precise mechanism of LDL formation from VLDL is unknown. During the last 15 years the processes of interc...

Watanabe Heritable Hyperlipidemic (WHHL) rabbits are an important animal model used to study the effects of defective low density lipoprotein (LDL) receptors on lipoprotein metabolism. In the present study, the receptor-mediated catabolism of apolipoprotein (apo) E-containing lipoproteins was investigated in fibroblasts and smooth muscle cells cultured from WHHL rabbits. Fibroblasts from WHHL r...

Subclasses of lipoproteins VLDL, LDL and HDL were isolated from plasma of two different phenotypes, A and B. Phenotype B is present in people with diabetes, atherosclerosis and higher risk for cardiovascular disease. Lipoproteins were studied by FT-IR spectroscopy to investigate conformational and structural differences reflected in spectra. Differences were observed in spectra of LDL and VLDL....

Triglyceride (TG) or more accurately triacylglycerol is simply a compound of three acyl groups (fatty acids) attached to a glycerol molecule. They are easily measured in the laboratory and reported as serum TG level: it actually refers to all of the TG that are being trafficked within all of the lipoproteins that exist in a deciliter of plasma. A physiologic fasting TG concentration is on avera...

Type 2 diabetes is characterized by increased plasma triglyceride levels and a fourfold increase in ischemic heart disease, but the mechanism is unclear. CD36 is a receptor/transporter that binds fatty acids of lipoproteins. CD36 deficiency has been linked with insulin resistance. There is strong evidence of in vivo interaction between platelets and atherogenic lipoproteins suggesting that athe...

Familial dysbetalipoproteinemia (or type III hyperlipoproteinemia) is characterized by the presence of abnormal, cholesteryl ester-rich beta-very low density lipoproteins (beta-VLDL) in the plasma. Subjects with typical dysbetalipoproteinemia are homozygous for an amino acid substitution in apolipoprotein (apo-) E at residue 158 and have defective apo-E-mediated binding of both pre-beta-VLDL an...

The uptake and degradation of cholesterol-rich remnant lipoproteins, referred to as beta-VLDL, are shown in the present study to be mediated by LDL receptors (apoB,E(LDL) receptors), not by unique beta-VLDL receptors. Human blood monocytes cultured for 5-7 d bound apoB- and/or apoE-containing lipoproteins from different species with affinities equivalent to those demonstrated for the receptors ...