High-density lipoproteins oxidation

Resch U, Mellauner V, Budinsky A, Sinzinger H (2004) Inhibition of low-density lipoprotein and high-density lipoprotein oxidation by raloxifene. J Womens Health (Larchmt) 13(4) 404-11... 

Aviram, M., et al. 1998. Paraoxonase inhibits high-density lipoprotein oxidation and preserves its functions. A possible peroxidative role for paraoxonase. J Clin Invest 101 1581. 

Ahmed, Z. et al. Apolipoprotein A-I promotes the formation of phosphatidylcholine core aldehydes that are hydrolyzed by paraoxonase (PON-1) during high density lipoprotein oxidation with a peroxynitrite donor. J. Biol. Chem. 276 (2001) 24473-81. 

Chin et al. (1992) have su ested that oxidized LDL and high-density lipoprotein (HDL) inactivate endothelial cell-derived NO. NO inactivation was due to the oxidized lipids within the lipoprotein particles and was thought to be explained by a chemical reaction between the lipoproteins and NO. Other investigators have shown that relaxation of vascular smooth muscle by acetylcholine or bradykinin (endothelium-dependent vasodilators) is inhibited by LDL (Andrews etal., 1987). The role of NO in the modification of LDL is discussed in full detail in Chapter 2. 

Contrary to LDL, high-density lipoproteins (HDL) prevent atherosclerosis, and therefore, their plasma levels inversely correlate with the risk of developing coronary artery disease. HDL antiatherogenic activity is apparently due to the removal of cholesterol from peripheral tissues and its transport to the liver for excretion. In addition, HDL acts as antioxidants, inhibiting copper- or endothelial cell-induced LDL oxidation [180], It was found that HDL lipids are oxidized easier than LDL lipids by peroxyl radicals [181]. HDL also protects LDL by the reduction of cholesteryl ester hydroperoxides to corresponding hydroperoxides. During this process, HDL specific methionine residues in apolipoproteins AI and All are oxidized [182]. 

X.-A. Li, W. B. Titlow, B. A. Jackson, N. Giltiay, M. Nikolova-Karakashian, A. Uittenbogaard, and E. J. Smart. High Density Lipoprotein Binding to Scavenger Receptor, Class B, Type I Activates Endothelial Nitric-oxide Synthase in a Ceramide-dependent Manner. J. Biol. Chem. 277 11058-11063 (2002). 

A. Uittenbogaard, P. W. Shaul, I. S. Yuhanna, A. Blair, and E. J. Smart. High density lipoprotein prevents oxidized low density lipoprotein-induced inhibition of endothelial nitric-oxide synthase localization and activation in caveolae. J. Biol. Chem. 275 11278-11283 (2000). 

Hexanal, hpid oxidation assessment, 669 1-Hexene, primary ozonide, 720 High-density lipoprotein (HDL) oxidation, 612 TEARS assay, 667 High-energy intermediate (HEI) chemiluminescence, 1215 activators, 1220, 1222 peroxyoxalates, 1188-9, 1257, 1261-6, 1267, 1269 stmcture, 1262, 1263... 

The role of the antioxidant properties of vitamins C, E, and p-carotene in the prevention of cardiovascular disease has been the focus of several recent studies. Antioxidants reduce the oxidation of low-density lipoproteins, which may play a role in the prevention of atherosclerosis. However, an inverse relationship between the intake or plasma levels of these vitamins and the incidence of coronary heart disease has been found in only a few epidemiological studies. One study showed that antioxidants lowered the level of high-density lipoprotein 2 and interfered with the effects of lipid-altering therapies given at the same time. While many groups recommend a varied diet rich in fruits and vegetables for the prevention of coronary artery disease, empirical data do not exist to recommend antioxidant supplementation for the prevention of coronary disease. 

High-density lipoproteins (HDL) exert several ant/atherogenic effects. They participate in retrieval of cholesterol from the artery wall and inhibit the oxidation of atherogenic lipoproteins. Low levels of HDL (hypoalphalipoproteinemia) are an independent risk factor for atherosclerotic disease and thus are a target for intervention. 

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. 

In vivo studies were also conducted by several researchers. Anraku et al. (2009) examined the antioxidant effects of water-soluble chitosan in normal subjects by measuring the reduction of indices of oxidative stress. Treatment with chitosan for 4weeks produced a significant decrease in levels of plasma glucose and the atherogenic index, and led to an increase in high-density lipoprotein cholesterol (HDL-C). Chitosan treatment also lowered the ratio of oxidized to reduced albumin and increased total plasma antioxidant activity. Further, Anraku et al. (2011) proved the antioxidant effects of high MW chitosan in normal volunteers, and the obtained results were consistent with previous results observed by Anraku et al. (2009). 

Bergt C, Fu X, Huq NP, Kao J, Heinecke JW (2004) Lysine Residues Direct the Chlorination of Tyrosines in YXXK Motifs of Apolipoprotein A-I When Hypochlorous Acid Oxidizes High Density Lipoprotein. J Biol Chem 279 7856... 

Mackness B, Mackness MI, Arrol S, Turkie W, Durrington PN. Effect of the human serum paraoxonase 55 and 192 genetic polymorphisms on the protection by high density lipoprotein against low density lipoprotein oxidative modification. FEB Lett 1998 423 57-60. 

Consumption of PJ for 1 and 2 weeks by healthy volunteers increased the resistance of their LDL to copper ion-induced oxidation, as shown by a prolongation of the lag time required for the initiation of LDL oxidation, by 29 and 43%, in comparison to LDL obtained prior to juice consumption (Figure 8.3C).28 Similarly, the resistance of their high-density lipoprotein (HDL) to copper ion-induced oxidation also gradually increased after PJ consumption, as shown by a prolongation in the... 

---