MitoQ supplementation for restoring aerobic exercise training effects on endothelial function in postmenopausal women

项目总结/文摘

PROJECT SUMMARY/ABSTRACT Endothelial dysfunction is a critical factor in the etiology of age-associated cardiovascular disease (CVD), the leading cause of death in postmenopausal women. Regular aerobic exercise (AE) enhances macro- and micro-vascular endothelial function in older men by reducing oxidative stress and preserving nitric oxide (NO) bioavailability, however, similar AE training improvements are diminished or absent in estrogen (E2)-deficient postmenopausal women. NO-mediated endothelial function and oxidative stress are improved with AE training in postmenopausal women treated with E2, suggesting an essential role of E2 in endothelial adaptations to AE in women. Clinical use of E2 is contraindicated for this purpose, thus establishing alternative pharmacological approaches that could be administered as a substitute for E2 to transduce AE signaling for vascular endothelial benefits and reducing CVD risk in E2-deficient postmenopausal women is biomedically important. The mitochondrial-targeted antioxidant MitoQ may be an alternative to E2 for restoring AE-endothelial signaling in E2-deficient postmenopausal women given its recently established effectiveness for reducing reactive oxygen species (ROS) and oxidative stress and improving endothelial function in that population. Accordingly, the overall aim of this application is to assess the efficacy of a 12-week randomized controlled trial of moderate intensity AE training combined with oral MitoQ (20 mg/d) compared to AE+oral placebo (PL) or No AE+MitoQ on macrovascular (brachial artery flow-mediated dilation; FMDBA) and microvascular (forearm blood flow response to intra-brachial infusion of acetylcholine; FBFAch) endothelial function in healthy E2-deficient postmenopausal women. Mechanistic insight related to NO bioavailability, mitochondrial function, ROS/oxidative stress, and the influence of “circulating factors” will also be obtained. We hypothesize that AE+MitoQ will improve both FMDBA and FBFAch > AE+PL and > No AE+MitoQ, and that No AE+MitoQ will improve FMDBA and FBFAch > AE+PL. The greater improvements in endothelial function with AE+MitoQ vs. both AE+PL and No AE+MitoQ, and with No AE+MitoQ vs. AE+PL will be mediated by greater improvements in NO bioavailability, mitochondrial function, and mitochondrial and whole cell ROS-related suppression of endothelial function linked, at least in part, to changes in “circulating factors”. The expected results from this study will establish the efficacy of MitoQ for restoring AE-endothelial signaling in E2-deficient postmenopausal women, and will provide the foundation for development of evidence-based guidelines for sex-specific AE programs for improving vascular health and preventing CVD in postmenopausal women.