A mitochondrial antioxidant improves endothelial function in adults, but baseline fitness level matters Original paper

In this randomized crossover study, a mitochondrial-targeted antioxidant improved endothelial function in adult participants with low cardiorespiratory fitness, but not in those with high cardiorespiratory fitness.

The effects of a mitochondrial-targeted antioxidant (MitoQ) on endothelial function in middle-aged and older adults who do or do not exercise regularly.

The primary outcome was endothelial function measured as brachial-artery flow-mediated dilation (FMD). Secondary outcomes included blood pressure and arterial stiffness (pulse wave velocity).

23 adults (average age of 62; 13 women, 10 men) who did not smoke and did not have any known cardiovascular diseases, metabolic diseases, or cancer.

The participants were divided into 2 groups: those who didn’t exercise and had a low cardiorespiratory fitness (CRF) (i.e., engaged in less than 75 minutes of vigorous aerobic exercise per week) and those who exercised and had a high CRF (i.e., engaged in 75 minutes or more of vigorous aerobic exercise per week).

A randomized crossover study was performed in which the participants ingested 80 mg of MitoQ or a placebo. The outcomes were assessed before and 1 hour after taking the interventions. A 1-week washout period separated each condition.

Before each experimental session, the participants fasted for 8–12 hours and were instructed to avoid caffeine, polyphenol-rich foods and drinks, high-fat meals, and nonsteroidal anti-inflammatory drugs (e.g., ibuprofen) for at least 12 hours; exercise for 12–24 hours; and aspirin for at least 72 hours.

In the nonexercisers with low CRF, MitoQ improved FMD by 37% compared to the placebo. FMD did not improve after MitoQ in the exercisers with high CRF.

MitoQ did not affect blood pressure or pulse-wave velocity in either group.

In all of the participants, a lower baseline CRF and a lower baseline FMD was associated with a greater improvement in FMD after MitoQ.

Surprisingly, supplementing with MitoQ did not increase the levels of plasma antioxidants (superoxide dismutase activity) compared to the placebo.