Circulating miRNA levels following a 14-wk aerobic exercise intervention during pregnancy: a secondary exploratory analysis of the PEACH RCT.

Abstract

Physical activity (PA) during pregnancy decreases the risk of developing hypertensive disorders of pregnancy by 40%, yet the underlying molecular mechanisms are unknown. microRNAs (miRNAs) have shown potential in cardiovascular disease prevention and diagnosis. Circulating levels of miR-21-3p and miR-146b-5p are associated with early pregnancy leisure time PA energy expenditure. However, it is not clear how miRNA levels change in response to exercise across pregnancy. We aimed to determine the change in circulating levels of miRNAs after a 14-wk, moderate-intensity aerobic exercise intervention in pregnant women. A subset of 10 pregnant women from the Prenatal Exercise and Cardiovascular Health (PEACH) study were included. Participants were randomized to a supervised aerobic exercise program (n = 5) or a control group (n = 5). At 18-21 (baseline) and 34-36 [postintervention (PI)] wk of pregnancy, a fasted blood draw and neurovascular assessment were carried out. Muscle sympathetic nerve activity burst incidence (BI), heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP), respectively, cardiac output (CO), and plasma miRNA levels were measured at each timepoint. Exercise prevented the rise in BI from baseline to PI. At baseline, both miRNA-146b-5p and miR-21-3p levels were not different between the groups. miR-21-3p increased from baseline to PI in both groups, but the exercise group had significantly higher levels at PI. A 14-wk aerobic exercise training intervention during pregnancy increases miR-21-3p levels in maternal plasma. Future work in a larger cohort will allow us to determine the relationship of miR-21-3p with maternal outcomes.NEW & NOTEWORTHY Pregnant women who were exposed to 14-wk aerobic exercise training intervention have increased miR-21-3p levels in plasma accompanied by an attenuation in the increase of burst incidence across pregnancy.