Changes in circulating microRNA and arterial stiffness following high-intensity interval and moderate intensity...

High-intensity interval (HII) exercise elicits distinct vascular responses compared to a matched dose of moderate intensity continuous (MOD) exercise. However, the acute effects of HII compared to MOD exercise on arterial stiffness are incompletely understood. Circulating microRNAs (ci-miRs) may contribute to the vascular effects of exercise. We sought to determine exercise intensity-dependent changes in ci-miR potentially underlying changes in arterial stiffness. Ten young, healthy men underwent well-matched, 30-min HII and MOD exercise bouts. RT-qPCR was used to determine the levels of seven vascular-related ci-miRs in serum obtained immediately before and after exercise. Arterial stiffness measures including carotid to femoral pulse wave velocity (cf-PWV), carotid arterial compliance and β-stiffness, and augmentation index (AIx and AIx75) were taken before, 10min after and 60min after exercise. Ci-miR-21-5p, 126-3p, 126-5p, 150-5p, 155-5p, and 181b-5p increased after HII exercise (p < .05), while ci-miR-150-5p and 221-3p increased after MOD exercise (p = .03 and 0.056). One hour after HII exercise, cf-PWV trended toward being lower compared to baseline (p = .056) and was significantly lower compared to 60min after MOD exercise (p = .04). Carotid arterial compliance was increased 60min after HII exercise (p = .049) and was greater than 60min after MOD exercise (p = .02). AIx75 increased 10 min after both HII and MOD exercise (p < .05). There were significant correlations between some of the exercise-induced changes in individual ci-miRs and changes in cf-PWV and AIx/AIx75. These results support the hypotheses that arterial stiffness and ci-miRs are altered in an exercise intensity-dependent manner, and ci-miRs may contribute to changes in arterial stiffness.