Biological Variation of Coenzyme Q10
摘要
Coenzyme Q10 (CoQ10) is an essential cofactor in the mitochondrial electron transport chain and is found in all cell membranes. It is present in the body in both the reduced and oxidized forms, with the reduced form (CoQ10H2) having antioxidant properties. CoQ10 has been implicated in disease processes, including Parkinson disease (1), diabetes (2), and Alzheimer disease(3), as well as in aging (4), oxidative stress (4)(5), and hydroxymethylglutaryl-CoA reductase inhibitor (statin) therapy (6). In particular, changes in CoQ10 may be relevant to statin-induced myalgia (7). Generally the bioavailability of dietary CoQ10 is low, and the formulations of CoQ10 supplements affect bioavailability (8)(9). There is also a significant difference between individuals in absorption of CoQ10 from supplements (9). Knowledge of the biological variation of CoQ10 in healthy individuals enables interpretation of whether a significant change has occurred in response to a disease state or supplementation. We investigated the inter- and intraindividual variation of plasma total CoQ10, the ratio of total CoQ10 to LDL-cholesterol (LDL-C), and the ratio of total CoQ10 to total cholesterol (TC). Reference intervals for these variables in healthy New Zealand adults were also determined. For determination of the inter- and intraindividual variation of CoQ10, 10 healthy adult male volunteers were enrolled. Exclusion criteria included taking CoQ10 or other vitamin supplements, smoking, and use of any medications within 4 weeks before initiation of the study. All participants were self-reportedly healthy and disease free throughout the study. The median age of the participants was 23.5 (range, 21–28) years, the median weight was 69 (60–100) kg, and the median body mass index (BMI) was 21.4 (18.5–28.6) kg/m2. Blood samples were taken in the morning after a 10-h fast. Samples were taken at least 1 week apart, over a period of 2 months, with seven samples being taken in total. Blood samples were col