Plasma coenzyme Q10 response to oral ingestion of coenzyme Q10 formulations.

Plasma coenzyme Q10 (CoQ10) response to oral ingestion of various CoQ10 formulations was examined. Both total plasma CoQ10 and net increase over baseline CoQ10 concentrations show a gradual increase with increasing doses of CoQ10. Plasma CoQ10 concentrations plateau at a dose of 2400 mg using one specific chewable tablet formulation. The efficiency of absorption decreases as the dose increases. About 95% of circulating CoQ10 occurs as ubiquinol, with no appreciable change in the ratio following CoQ10 ingestion. Higher plasma CoQ10 concentrations are necessary to facilitate uptake by peripheral tissues and also the brain. Solubilized formulations of CoQ10 (both ubiquinone and ubiquinol) have superior bioavailability as evidenced by their enhanced plasma CoQ10 responses.

Assessment of coenzyme Q10 absorption using an in vitro digestion-Caco-2 cell model.

The feasibility of using a coupled in vitro digestion-Caco-2 cell uptake as a model for examining the digestive stability and absorption of coenzyme Q10 (CoQ10) from a variety of commercially available CoQ10 products was examined. The products were first subjected to simulated digestion to mimic their passage through the GI tract to generate micelles containing CoQ10, and the micelle fractions added to monolayers of Caco-2 cells to determine CoQ10 uptake. The data demonstrate enhanced uptake of CoQ10 from formulations containing solubilized forms of CoQ10 and also from a CoQ10-gamma-cyclodextrin complex as compared with pure CoQ10 powder or tablets based on CoQ10 powder. The CoQ10 uptake by the cells was correlated with the extent of micellarization of CoQ10 during simulated digestion. Most of CoQ10 taken up by the cells was converted to ubiquinol either during or following uptake. The data also indicate a correlation between in vitro dissolution of CoQ10 products and uptake of CoQ10 by Caco-2 cells. Thus, this study demonstrates the utility of coupled in vitro digestion-Caco-2 cell model as a cost-effective screening tool that will provide useful information for the optimal design of human trials to assess the bioavailability of CoQ10 and also other bioactive compounds.

Coenzyme Q10: absorption, tissue uptake, metabolism and pharmacokinetics.

Available data on the absorption, metabolism and pharmacokinetics of coenzyme Q10 (CoQ10) are reviewed in this paper. CoQ10 has a fundamental role in cellular bioenergetics. CoQ10 is also an important antioxidant. Because of its hydrophobicity and large molecular weight, absorption of dietary CoQ10 is slow and limited. In the case of dietary supplements, solubilized CoQ10 formulations show enhanced bioavailability. The T(max) is around 6 h, with an elimination half-life of about 33 h. The reference intervals for plasma CoQ10 range from 0.40 to 1.91 micromol/l in healthy adults. With CoQ10 supplements there is reasonable correlation between increase in plasma CoQ10 and ingested dose up to a certain point. Animal data show that CoQ10 in large doses is taken up by all tissues including heart and brain mitochondria. This has implications for therapeutic applications in human diseases, and there is evidence for its beneficial effect in cardiovascular and neurodegenerative diseases. CoQ10 has an excellent safety record.

Potential role of ubiquinone (coenzyme Q10) in pediatric cardiomyopathy.

Pediatric cardiomyopathy (PCM) represents a group of rare and heterogeneous disorders that often results in death. While there is a large body of literature on adult cardiomyopathy, all of the information is not necessarily relevant to children with PCM. About 40% of children who present with symptomatic cardiomyopathy are reported to receive a heart transplant or die within the first two years of life. In spite of some of the advances in the management of PCM, the data shows that the time to transplantation or death has not improved during the past 35 years. Coenzyme Q10 is a vitamin-like nutrient that has a fundamental role in mitochondrial function, especially as it relates to the production of energy (ATP) and also as an antioxidant. Based upon the biochemical rationale and a large body of data on patients with adult cardiomyopathy, heart failure, and mitochondrial diseases with heart involvement, a role for coenzyme Q10 therapy in PCM patients is indicated, and preliminary results are promising. Additional studies on the potential usefulness of coenzyme Q10 supplementation as an adjunct to conventional therapy in PCM, particularly in children with dilated cardiomyopathy, are therefore warranted.