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Abstract
Hypercholesterolaemia and atherosclerosis impair responses to endothelium-derived
nitric oxide (EDRF) in human and animal coronary arteries, a dysfunction that correlates
with elevated low denisty lipoproteins (LDL). Previous studies show that native LDL
immediately and reversibly inhibit acetylcholine-evoked EDRF responses in rabbit aortic
ring precontracted with noradrenaline or serotonin whereas Cu2+-oxidised LDL (oxLDL) inhibit relaxations after 30 min with a potency that varies
with the donor. We now show that antioxidants, probucol (10 μM) and ascorbic acid
(100 μM) in vitro, prevent the inhibition by native LDL, indicating that this effect
involves free radicals. As expected, the antioxidants had no influence on the inhibition
by oxLDL. Superoxide dismutase appeared to have no effect on the inhibition by native
or oxLDL. The oral administration of probucol to selected volunteers also prevented
the inhibition of relaxation by their native LDL. These preparations showed a diminished
susceptibility to oxidation and their oxLDL caused a markedly reduced and always reversible
inhibition of relaxation compared to the potent and sometimes irreversible inhibition
prior to administration of the drug. We conclude that antioxidants such as probucol
reduce the formation of free radicals and the oxidative modification of LDL that lead
to the impairment of EDRF responses and may prevent this same dysfunction in hypercholesterolaemia
and atherosclerosis.
Keywords
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References
- Lipoproteins and atherogenesis.J. Am. Med. Assoc. 1990; 264: 3047
- Attenution of atherosclerosis in a modified strain of hypercholesterolaemic Watanabe rabbits with use of probucol analogue (MDL 29 311) that does not lower cholesterol.Arteriosclerosis. 1991; 11: 1266
- Atherosclerosis or lipoprotein-induced endothelial function.Circulation. 1992; 85: 1927
- Endothelial function in human coronary arteries in vivo. Focus on hypercholesterolaemia.Hypertension. 1991; 18: 90
- Native and oxidized low-density lipoproteins have different inhibitory effects on endothelium-derived relaxing factor in rabbit aorta.Br. J. Pharmacol. 1990; 100: 21
- Oxidative modification of low-density lipoproteins and the inhibition of relaxation mediated by endotheliumderived nitric oxide in rabbit aorta.Br. J. Pharmacol. 1992; 105: 216
- Rapid oxidation of plasma lowdensity lipoprotein in coronary heart disease.Br. Heart J. 1991; 66: 78
- Susceptibility to low-density lipoprotein oxidation and coronary atherosclerosis in man.Lancet. 1992; 33: 1183
- Continuous monitoring of in vitro oxidation of human low-density lipoprotein.Free Rad. Res. Commun. 1989; 6: 66
- Chronic-treatment with polyethylene-glycolated superoxide dismutase partially restores endothelium-dependent vascular relaxations in cholesterol-fed rabbits.Circ. Res. 1991; 69: 1293
- Free Radicals in Biology and Medicine.in: 2nd Edn. Clarendon Press, Oxford1989: 137
- Free Radicals in Biology and Medicine.in: 2nd Edn. Clarendon Press, Oxford1989: 76
- Lipid hydroperoxide involvement in copper-dependent and independent oxidation of low-density lipoproteins.J. Pharmacol. Exp. Ther. 1991; 25: 182
- Apparent hydroxyl radical production by peroxynitrite: implications for endothelial injury from ni tric oxide and superoxide.in: Proc. Natl. Acad Sci. USA. 87. 1990: 1620
- The production of hydroxyl radicals from the simultaneous generation of superoxide and nitric oxide.Biochem. J. 1992; 281: 419
- Probucol, a superoxide free radical scavenger in vitro.Atherosclerosis. 1991; 89: 263-265
- Vitamin E protects against impairment of endothelium-dependent relaxation in cholesterol-fed rabbit carotid artery.Br. J. Pharmacol. 1992; 107: 405P
Article info
Publication history
Accepted:
July 4,
1993
Received in revised form:
May 25,
1993
Received:
October 19,
1992
Identification
Copyright
© 1993 Elsevier Scientific Publishers Ireland Ltd. All rights reserved. Published by Elsevier Inc.