scholarly journals Very-Low-Density Lipoprotein: Complex Particles in Cardiac Energy Metabolism

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
You-Guo Niu ◽  
Rhys D. Evans
Keyword(s):  
Fatty Acids ◽  
Energy Metabolism ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Very Low Density Lipoprotein ◽  
Low Density ◽  
Nonesterified Fatty Acids ◽  
Wide Range ◽  
Cardiac Energy Metabolism ◽  
Cardiac Energy

The heart is a major consumer of energy and is able to utilise a wide range of substrates including lipids. Nonesterified fatty acids (NEFA) were thought to be a favoured carbon source, but their quantitative contribution is limited because of their relative histotoxicity. Circulating triacylglycerols (TAGs) in the form of chylomicrons (CMs) and very-low-density lipoprotein (VLDL) are an alternative source of fatty acids and are now believed to be important in cardiac metabolism. However, few studies on cardiac utilisation of VLDL have been performed and the role of VLDL in cardiac energy metabolism remains unclear. Hearts utilise VLDL to generate ATP, but the oxidation rate of VLDL-TAG is relatively low under physiological conditions; however, in certain pathological states switching of energy substrates occurs and VLDL may become a major energy source for hearts. We review research regarding myocardial utilisation of VLDL and suggest possible roles of VLDL in cardiac energy metabolism: metabolic regulator and extracardiac energy storage for hearts.

Quercetin alters energy metabolism in swimming mice

2012 ◽  
Vol 37 (5) ◽  
pp. 912-922 ◽  
Author(s):  
Jianquan Wu ◽  
Weina Gao ◽  
Jingyu Wei ◽  
Jijun Yang ◽  
Lingling Pu ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Energy Metabolism ◽  
Metabolic Profile ◽  
Unsaturated Fatty Acids ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Physical Endurance ◽  
Low Density ◽  
Metabolomic Analysis ◽  
Nonesterified Fatty Acids

Quercetin has been demonstrated to be effective in increasing physical endurance in mice and humans. However, the mechanisms involved are not fully understood. In this study, male Kunming mice were fed a diet containing 0.1% quercetin for 14 days before swimming for 60 min. The overall serum metabolic profile was investigated by a 1H nuclear magnetic resonance-based metabolomic approach. Serum glucose, lactate, nonesterified fatty acids (NEFA), and nonprotein nitrogen (NPN), as well as hepatic and muscular glycogen were measured biochemically. The results of metabolomic analysis showed that swimming induced a significant change in serum metabolic profile. Relative increases in the levels of lactate, alanine, low-density lipoprotein–very low-density lipoprotein, and unsaturated fatty acids, and decreases in choline, phosphocholine, and glucose were observed after swimming. With quercetin supplementation, these changes were attenuated. The results of biochemical assays were consistent with the data obtained from metabolomic analysis, in that serum NEFA was increased while lactate and NPN decreased after exposed to quercetin in swimming mice. Similar change in NEFA was also found in liver and gastrocnemius muscle tissues. Our current findings suggest that quercetin alters energy metabolism in swimming mice and increased lipolysis may contribute to the actions of quercetin on physical endurance.

scholarly journals The lipolysis/esterification cycle of hepatic triacylglycerol. Its role in the secretion of very-low-density lipoprotein and its response to hormones and sulphonylureas

1992 ◽  
Vol 284 (2) ◽  
pp. 457-462 ◽  
Author(s):  
D Wiggins ◽  
G F Gibbons
Keyword(s):  
Fatty Acids ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Very Low Density Lipoprotein ◽  
Low Density ◽  
Intracellular Pool ◽  
Hepatocyte Cultures ◽  
Vldl Secretion ◽  
Vldl Assembly ◽  
Hepatic Triacylglycerol

In hepatocyte cultures maintained in the absence of extracellular fatty acids, at least 70% of the secreted very-low-density lipoprotein (VLDL) triacylglycerol was derived via lipolysis of intracellular triacylglycerol. This proportion was unchanged when the cells were exposed for 24 h to insulin or glucagon, hormones which decreased the overall secretion of intracellular triacylglycerol, or to chloroquine or tolbutamide, agents which inhibit lysosomal lipolysis. The rate of intracellular lipolysis was 2-3-fold greater than that required to maintain the observed rate of triacylglycerol secretion. Most of the fatty acids released were returned to the intracellular pool. Neither insulin nor glucagon had any significant effect on the overall lipolysis and re-esterification of intracellular triacylglycerol. In these cases a greater proportion of the released fatty acids re-entered the cellular pool, rather than being recruited for VLDL assembly. Tolbutamide inhibited intracellular lipolysis, but suppressed VLDL secretion to a greater extent. 3,5-Dimethylpyrazole did not affect lipolysis or VLDL secretion. The increased secretion of VLDL triacylglycerol observed after exposure of cells to insulin for 3 days was not accompanied by an increased rate of intracellular lipolysis. However, a larger proportion of the triacylglycerol secreted under these conditions may not have undergone prior lipolysis.

Variation in Human Erythrocyte Membrane Unsaturated Fatty Acids: Correlation With Cardiovascular Disease

2010 ◽  
Vol 134 (1) ◽  
pp. 73-80
Author(s):  
Jorge L. Sepulveda ◽  
Yvette C. Tanhehco ◽  
Monica Frey ◽  
Lida Guo ◽  
Lorna J. Cropcho ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Vascular Disease ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Low Density ◽  
Low Density Lipoprotein Cholesterol ◽  
Fa Composition ◽  
Wide Range ◽  
Trans Fa ◽  
Cis And Trans

Abstract Context.—Whether cell membrane fatty acid (FA) composition is a useful indicator of vascular disease is unclear. Objective.—To study variation of erythrocyte (RBC) membrane FA in samples from healthy volunteers, hospitalized patients, and cardiac troponin I–elevated patients with myocardial damage without a priori assumptions as to FA composition. Design.—We separated FAs extracted from RBCs by gas chromatography and identified them by mass spectrometry. Fatty acids with abundance greater than 1% of total were quantified and compared: hexadecanoic (C16:0), octadecadienoic (C18:2), cis- and trans-octadecenoic (C18:1), and eicosatetraenoic (C20:4) acids. Deuterated standards established proportionality of FA recovery. The cis- and trans-C18:1 identification was verified by comparison with standards. Results.—In troponin-positive samples, C18:2 to C18:1 ratios were increased 30% compared with healthy controls or with random patient samples. Erythrocyte trans-C18:1 had a wide variation, ∼10-fold, in all groups but without differences between groups. Replicates showed that the wide range of RBC trans-FA load is not due to analytic variation. In healthy subjects, the RBC content of lower– molecular weight FAs (C16-C18) correlated with serum low-density lipoprotein cholesterol, but despite the established relationship between dietary trans-FA and increased low-density lipoprotein cholesterol, lipid profiles had no correlation with RBC trans-FA content. Conclusions.—Erythrocyte accumulation of unsaturated FA may be a useful indicator of vascular disease, whereas the wide range in trans-FAs suggests that both diet and genetic variation affect RBC trans-FA accumulation. Unsaturated FAs increase membrane fluidity and may reflect a natural response to subclinical vascular changes, which may in turn reflect increased risk of clinical disease.

scholarly journals Stimulation of triacylglycerol synthesis in rat adipocytes by plasma very-low-density lipoproteins

1978 ◽  
Vol 176 (1) ◽  
pp. 169-174 ◽  
Author(s):  
P Thomopoulos ◽  
M Berthelier ◽  
D Lagrange ◽  
M J Chapman ◽  
M H Laudat
Keyword(s):  
Fatty Acids ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Low Density Lipoproteins ◽  
High Density Lipoproteins ◽  
Very Low Density Lipoprotein ◽  
Low Density ◽  
Very Low Density Lipoproteins ◽  
Rat Adipocytes ◽  
Triacylglycerol Synthesis

The effect of human plasma lipoproteins on lipogenesis from glucose has been studied in isolated rat adipocytes. The very-low-density lipoproteins increased lipogenesis specifically, whereas low-density lipoproteins and high-density lipoproteins were without effect. Such stimulation could be reproduced with partially delipidated very-low-density lipoproteins. Nod-esterified fatty acids and glycerol were also without effect. Pretreatment of the adipocytes with trypsin did not alter the effect of very-low-density lipoprotein. The presence of Ca2+ was required for the full activation of lipogenesis. The synthesis of acylglycerol fatty acids and of acylglycerol glycerol were equally increased. The effect of very-low-density lipoprotein was not additive to that of insulin. It is suggested that very-low-density lipoprotein may directly stimulate lipogenesis in fat-cells, particularly in states when the lipoproteins are present at high concentration in the circulation.

Sign in / Sign up

Export Citation Format

Share Document