Coenzyme Q improves LDL resistance to ex vivo oxidation but does not enhance endothelial function in hypercholesterolemic young adults

Citation
Ot. Raitakari et al., Coenzyme Q improves LDL resistance to ex vivo oxidation but does not enhance endothelial function in hypercholesterolemic young adults, FREE RAD B, 28(7), 2000, pp. 1100-1105
Citations number
52
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biochemistry & Biophysics
Journal title
FREE RADICAL BIOLOGY AND MEDICINE
ISSN journal
0891-5849 → ACNP
Volume
28
Issue
7
Year of publication
2000
Pages
1100 - 1105
Database
ISI
SICI code
0891-5849(20000401)28:7<1100:CQILRT>2.0.ZU;2-R
Abstract
Oxidative modification of low-density lipoprotein (LDL) may cause arterial endothelial dysfunction in hyperlipidemic subjects. Antioxidants can protec t LDL from oxidation and therefore improve endothelial function. Dietary su pplementation with coenzyme Q (CoQ(10)) raises its level within LDL, which may subsequently become more resistant to oxidation. Therefore, the aim of this study was to assess whether oral supplementation of CoQ(10) (50 mg thr ee times daily) is effective in reducing ex vivo LDL oxidizability and in i mproving vascular endothelial function. Twelve nonsmoking healthy adults wi th hypercholesterolemia (age 34 +/- 10 years, nine women and three men, tot al cholesterol 7.4 +/- 1.1 mmol/l) and endothelial dysfunction (below popul ation mean) at baseline were randomized to receive CoQ(10) or matching plac ebo in a double-blind crossover study (active/placebo phase 4 weeks, washou t 4 weeks). Flow-mediated (FMD, endothelium-dependent) and nitrate-mediated (NMD, smooth muscle-dependent) arterial dilatation were measured by high-r esolution ultrasound. CoQ(10) treatment increased plasma CoQ(10) levels fro m 1.1 +/- 0.5 to 5.0 +/- 2.8 mu mol/l (p = .009) but had no significant eff ect on FMD (4.3 +/- 2.4 to 5.1 +/- 3.6 %, p = 99), NMD (21.6 +/- 6.1 to 20. 7 +/- 7.8 %, p = .38) or serum LDL-cholesterol levels (p = .51). Four subje cts were selected randomly for detailed analysis of LDL oxidizability using aqueous peroxyl radicals as the oxidant. In this subgroup, CoQ(10) supplem entation significantly increased the time for CoQ(10)H(2) depletion upon ox idant exposure of LDL by 41 +/- 19 min (p = .04) and decreased the extent o f lipid hydroperoxide accumulation after 2 hours by 50 +/- 37 mu mol/l (p = .04). We conclude that dietary supplementation with CoQ(10) decreases ex-v ivo LDL oxidizability but has no significant effect on arterial endothelial function in patients with moderate hypercholesterolemia. (C) 2000 Elsevier Science Inc.