MITOQ ACUTELY ENHANCES MYOCARDIAL PERFUSION IN NON-EXERCISING MIDDLE-AGED AND OLDER ADULTS WITH LOWER CARDIORESPIRATORY FITNESS

BACKGROUND: Non-exercising middle-aged and older adults (MA/O) with lower cardiorespiratory fitness (CRF) have lower myocardial perfusion which can be potentially enhanced with mitochondrial-targeted antioxidants. The acute mitochondrial-targeted antioxidant effects on myocardial perfusion are currently unknown. PURPOSE: To determine the acute effects of the mitochondrial-targeted antioxidant, MitoQ, on myocardial perfusion and if these effects are associated with CRF. METHODS: In a double-blind, randomized, placebo-controlled crossover study design twenty-two (10 M/12F, age 62.4 ± 2.5 y) MA/O adults (≥45 y) were divided into two groups; exercisers (EX, n = 11) and non-exercisers (NEX, n = 11). CRF (VO2max) was assessed from an incremental ramp protocol on a cycle ergometer. Myocardial perfusion via the subendocardial viability ratio (SEVR) from pulse wave analysis (PWA, SphygmoCor XCEL) was assessed before (pre-ingestion) and ~ 1 h after MitoQ (single dose, 80 mg) or placebo supplementation. A two-way repeated measures ANOVA with a Bonferroni post-hoc analysis was used to determine the effects of MitoQ and placebo on SEVR. An unpaired independent samples t-test was used to determine differences in the absolute and relative change in SEVR between NEX and EX. Pearson correlations were used to assess the relations between baseline CRF and SEVR and the change in SEVR with MitoQ and CRF. RESULTS: MitoQ did not increase SEVR in the whole cohort (153.5 ± 7.6 vs 158.2 ± 6.7 %, p > 0.05). However, when divided into groups by exercise status, MitoQ increased SEVR in NEX by 7.1% (+5% relative) (both, p < 0.05). No changes were observed for MitoQ on SEVR in EX (p > 0.05). Baseline SEVR was positively correlated with CRF (n = 16, r = 0.69, p < 0.05) and the change in SEVR with MitoQ trended to be inversely associated with CRF (r = -0.49, p = 0.055). CONCLUSION: These findings demonstrate the potential for MitoQ as a viable strategy to improve myocardial perfusion in NEX adults which is also associated with lower CRF. FUNDING: Funding for this study was provided, in part, by Ball State University ASPiRE internal research grant (N. A. Carlini).