Ubiquinol-10 and total peroxyl radical trapping capacity of LDL lipoproteins during aging: The effects of Q-10 supplementation

Abstract

Evidence is rapidly accumulating that oxidative modification of low density lipoprotein (LDL) may play an important role in the pathogenesis of atherosclerosis. In this study we measured the total peroxyl radical trapping capacity of human plasma LDL phospholipids (TRAP LDL) with a luminescent method. The study was carried out with 70 healthy volunteers, aged 28–77. In males an age-related decrease in TRAP LDL was observed. In the age group under 50 years the mean TRAP LDL was 31.36 ± 1.45 pmol peroxyl radicals/nmol Pi; among those over 50 years it was significantly lower at 26.67 0.94 pmol/nmol Pi. As regards the components of TRAp LDL, the concentration of LDL-ubiquinol did not change and a non-significant decrease in the LDL-tocopherol concentration was detected with age. In females, the mean TRAP LDL, LDL-ubiquinol-10 and tocopherol concentrations did not differ between the age groups. When 17 of the participants were given coenzyme Q 10 (Q 10) supplementation, 100 mg/day, a highly significant increase in LDL-ubiquinol concentration was detected. Our results indicate that LDL antioxidant defenses tend to decrease with age in the Finnish male population. The decline is most significant in males under 50 years; in older age groups the values remain stable at a low level. Q 10 supplementation doubles the number of ubiquinol-10-containing LDL molecules and may therefore have an inhibitory effect on LDL oxidation.