Presence of multiple subpopulations of lipoproteins of intermediate density in normal subjects.

Abstract

Analysis of human plasma by gradient gel electrophoresis (GGE) revealed multiple distinct bands in the size range between very low density (VLDL) and low density lipoproteins (LDL). GGE of intermediate density lipoproteins (IDL) from normal subjects consistently showed two major bands with particle diameters in the range of 275 to 300 A. The larger, usually predominant subspecies was designated IDL-1, and the smaller, IDL-2. GGE also demonstrated two sizes of subpopulations in the VLDL density range in all subjects. A discontinuous nonequilibrium density gradient ultracentrifugation technique was devised to isolate a series of fractions containing progressively smaller lipoproteins. Successive fractions showed progressive enrichment in cholesteryl-esters, depletion of triglyceride, slower migration on agarose, and depletion of apo E and the C apolipoproteins relative to apo B. The IDL-1 and IDL-2 subspecies appeared to represent two distributions of lipoproteins overlapping in size (particle diameter 280-300 A and 268-284 A, respectively) and buoyant density (d = 1.008-1.022 g/ml and d = 1.013-1.028 g/ml, respectively). Plasma from two patients with dysbetalipoproteinemia showed predominant increases in fractions normally containing small VLDL and IDL-1, while patients with severe hypertriglyceridemia had increases primarily in levels of larger VLDL. Heterogeneity of lipoprotein precursors could account for the discrete subspecies of LDL observed in human plasma. (Arteriosclerosis

Detection of two species of low density lipoprotein particles in cholesteryl ester transfer protein deficiency.

“…They demonstrated the existence of two sizes of subpopulations in both VLDL and DDL, but only one in LDL, of normal human plasma. 21 The occurrence of the early transfer of cholesteryl ester from HDL to apo B-containing lipoproteins could be supported by their findings. In this study, we could not clearly separate two species of VLDL particles.…”

Lipase Activities in Post-heparin Plasma and Tissues, and Susceptibilities of Lipoproteins in Experimental Diabetic Rats

“…Atherogenicity of VLDL is regarded to be weak compared with that of IDL or LDL (65,66). Previously, diabetic rats , fed a diet containing 0.25 percent Ch for 12 months, showed marked hyperlipidemias and severe atheromatous lesions in their aortas (9).…”

Overexpression of Human Hepatic Lipase and ApoE in Transgenic Rabbits Attenuates Response to Dietary Cholesterol and Alters Lipoprotein Subclass Distributions

“…20,22 In brief, lipoproteins of density (g/mL) Ͻ1.019 (VLDLϩIDL), 1.019 to 1.063 (LDLs), and 1.063 to 1.21 (HDLs) were isolated through preparative ultracentrifugation under standard conditions. 30 Sodium bromide was added to adjust densities and samples were centrifuged at 40 000 rpm for 18 to 20 hours (VLDLϩIDL), 24 to 26 hours (LDLs), and 24 hours (HDLs) at 10°C in a Beckman 40.3 fixed-angle rotor.…”

“…16 Although VLDLϩIDL and LDLs are commonly defined as lipoproteins of density Ͻ1.019 and 1.019 to 1.063 g/mL, respectively, among these intervals it is possible to recognize several heterogeneous subclasses, differing in size, density, flotation rate, electrophoretic mobility, and chemical composition. [17][18][19][20][21][22][23][24][25] We previously used density-gradient ultracentrifugation (DGUC) and electrophoresis in polyacrylamide gradient gels to demonstrate the existence of multiple distinct subclasses of VLDLs and IDLs in humans. 19,20 By injecting human lipoproteins into rats, we documented different met-abolic pathways for distinct VLDL and IDL subclasses.…”

“…[17][18][19][20][21][22][23][24][25] We previously used density-gradient ultracentrifugation (DGUC) and electrophoresis in polyacrylamide gradient gels to demonstrate the existence of multiple distinct subclasses of VLDLs and IDLs in humans. 19,20 By injecting human lipoproteins into rats, we documented different met-abolic pathways for distinct VLDL and IDL subclasses. 21 The LDLs also contain multiple distinct subpopulations of particles.…”