High density lipoproteins composition

Kawano J, Ney DM, Keen CL, et al. 1987. Altered high density lipoprotein composition in manganese-deficient Sprague-Dawley and Wistar rats. J Nutr 117 902-906. 

Heterogeneous Non-uniform composition, 4 catalysis, 305-306 equilibrium, 329-331 High-density lipoprotein, 603 High-spin complex A complex that, for a particular metal cation, has the largest number of unpaired electrons, 419 Hindenburg, 111... 

The fate of injected liposomes is drastically altered by administration route, dose and size, lipid composition, surface modification, and encapsulated drugs. Liposomes encapsulating drugs are often administered iv, therefore, the stability of liposomes in plasma is important. When liposomes composed of PC with unsaturated fatty acyl chains are incubated in the presence of serum, an efflux of internal solute from the liposomes is observed. This increase in permeability is caused by the transfer of phospholipids to high density lipoprotein (HDL) in serum (55). To reduce the efflux of liposomal contents, cholesterol is added as a liposomal component... 

Lipoproteins. A lipoprotein is an endogenous macromolecule consisting of an inner apolar core of cholesteryl esters and triglycerides surrounded by a monolayer of phospholipid embedded with cholesterol and apoproteins. The functions of lipoproteins are to transport lipids and to mediate lipid metabolism. There are four main types of lipoproteins (classified based on their flotation rates in salt solutions) chylomicrons, very-low-density lipoprotein (VLDL), low-density lipoprotein (LDL), and high-density lipoprotein (HDL). These differ in size, molecular weight, and density and have different lipid, protein, and apoprotein compositions (Table 11). The apoproteins are important determinants in the metabolism of lipoproteins—they serve as ligands for lipoprotein receptors and as mediators in lipoproteins interconversion by enzymes. 

Alterations in the composition of the plasma lipids caused by estrogens are characterized by an increase in the high-density lipoproteins (HDL), a slight reduction in the low-density lipoproteins (LDL), and a reduction in total plasma cholesterol levels. Plasma triglyceride levels are increased. Estrogens decrease hepatic oxidation of adipose tissue lipid to ketones and increase synthesis of triglycerides. 

Figure 3.11 Composition (%) of human serum lipoproteins VLDL, very low density lipoproteins LDL, low density lipoproteins HDL, high density lipoproteins.

The plasma lipoproteins are spherical macromolecular complexes of lipids and specific proteins (apolipoproteins or apoproteins). The lipoprotein particles include chylomicrons, very-low-density lipoproteins (VLDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL). They differ in lipid and protein composition, size, and density (Figure 18.13). Lipoproteins function both to keep their component lipids soluble as they transport them in the plasma, and also to provide an efficient mechanism for transporting their lipid contents to (and from) the tissues. In humans, the transport system is less perfect than in other animals and, as a result, humans experience a yradual deposition of lipid—especially cholesterol—in tissues. This is a potentially life-threat-en ng occurrence when the lipid deposition contributes to plaque formation, causing the narrowing of blood vessels (atherosclerosis). 

L2. Lagocki, P. A., and Scanu, A. M., In vitro modulation of the apolipoprotein composition of high density lipoprotein. Displacement of apolipoprotein A-I from high density lipoprotein by apolipoprotein A-II. /. Biol. Chem. 255, 3701-3706 (1980). 

Table 1. Composition of High Density Lipoproteins in Insects and Man...

The typical sunflower oil composition is 66-72% linoleic acid, 12% saturated acids (palmitic and stearic), 16-20% oleic acid, and less than 1% a-linolenic acid. An increase in low-density lipoprotein cholesterol (LDL-C) and a decrease of high-density lipoprotein cholesterol (HDL-C) are believed risk factors of coronary heart disease (CHD). Diets rich in saturated fat increase plasma total and LDL-C. Traditional high-linoleic sunflower oil has always been regarded as healthy because of its high content of polyunsaturated fatty acids (PUFA) and relatively low content in saturated fatty acids. 

Fig. 1. General oil-droplet model of lipoproteins is presented for chylomicron, very low-density lipoprotein (VLDL), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) structures. Apolipoproteins in the outer phospholipid membrane, designated by letters, are defined in Table II. The major differences between the lipoproteins are the size of the neutral lipid (triglyceride and esterified cholesterol) core, liquid composition in the core, and apolipoprotein composition. (E) Triglycerides, ( Q ) phospholipids, and ( -) esterified cholesterol are shown. Although not shown, unesterified cholesterol is found predominantly in the phospholipid monolayer.

Coronary heart disease (CHD) is one of the leading causes of morbidity and mortality in the United States. Hyperlipidemia is a major risk factor for atherosclerosis and CHD. Hyperlipidemia is defined as an elevation in blood cholesterol or triglycerides (TG). Lipids are primarily transported in the body by three major lipoproteins low-density (LDL), very-low-density (VLDL), and high-density lipoproteins (HDL). Cholesteryl esters and TG are carried by the lipoproteins, which vary in size and composition of cholesterol and... 

Figure 26-18 Exogenous lipoprotein metabolism pathway. TG, Triglyceride CE, cholesterol ester FC, free cholesterol Ft, phospholipids HDL, hIgh-density lipoproteins FA, fatty acid LPL, lipoprotein lipase 6, apolipoprotein B-48 A, apolipoprotein A-i C, apolipoprotein C-ll , apolipoprotein E. (From Rifai N. Lipoproteins and apolipoproteins Composition, metabolism, and association with coronary heart disease. Arch Pathol Lab Med 1986 10 694-701. Copyright 1986, American Medical Association.)...

Imaizumi S, Navab M, Morgantini C, Charles-Schoeman C, Su F, Gao F, Kwon M, Ganapathy E, Meriwether D, Farias-Eisner R, Fogelman AM, Reddy ST (2011) Dysfunctional high-density lipoprotein and the potential of apolipoprotein A-l mimetic peptides to normalize the composition and function of lipoproteins. CircJ 75 1533-1538... 

Lipids with high levels of polyunsaturated fatty acids are considered desirable by many nutritionists because these lipids help to maintain low levels of blood cholesterol and favorable levels of serum high density lipoproteins. Many efforts are now directed at modification of the fatty acid composition in plants, especially the composition of seed oils (5). Genetic improvement of soybean oil is an especially desirable goal since the small amount of a-linolenic acid present in the oil causes flavor instability. 

The TAG show higher proportions of palmitoleic and oleic acids. The FA composition of TAG in the high-density lipoprotein (HDL) fraction in the granules and the low-density lipoprotein (LDL) fraction of the yolk plasma show similar composition (Tables 14.8 and 14.9). 

Tsutsui, T. and Obara, T. 1979. Lipid and fatty acid composition of low density lipoprotein and high density lipoprotein of egg yolk, Nippon Shokuhin Kogyo Gakkaishi, 26, 81. 

It is our primary purpose here to emphasize some potentially important revisions in lipoprotein procedure, including additions to the technology of lipoprotein analysis. At the same time, we wish to present some recent data on lipoprotein composition determined by improved lipid analytical techniques. Finally, as a preliminary application of these techniques, we have included the evaluation of correlations between the major variables studied, including all measiued portions of the low- and high-density lipoprotein spectra as observed in an adult male and female population. 

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