Endurance Exercise Controls the Level of Inflammatory miR-155 and Angiogenic miR-210

Numerous chronic illnesses can be prevented and treated by regular exercise, particularly continuous exercise. Although recent research indicates that epigenetic processes, specifically miRNAs, may play a role in the genesis and regulation of exercise-related alterations, the molecular and cellular mechanisms underlying the adaptive response to physical activity remain unclear. To assess an individual's response to diet, exercise, and metabolic factors, a “fitness score” was developed by integrating the assessment of genetic predispositions, dietary and supplement intake, and epigenetic biomarkers (miRNAs).

This non-randomized controlled pilot study included 20 inactive, healthy adults divided into a supervised endurance-training intervention group (n = 10) and an age, sex, and BMI-matched sedentary control group (n = 10). The intervention group worked out three to four times a week for four weeks, increasing the intensity of their treadmill endurance exercise from 65% to 75% of their maximal Heart Rate (HRmax). HRmax was estimated using the Tanaka equation (208 − 0.7 × age), and exercise intensity was monitored using Polar H10 chest belts. At baseline and 4 weeks, venous samples were drawn; in the intervention group, samples were obtained 4 weeks post-intervention within 30 minutes after the last supervised exercise session and processed as plasma for qPCR analysis of expression of miR-155 and miR-210.

Plasma miR-155 concentration showed a significant increase after 4 weeks of endurance training (P = 0.008). On the contrary, there were no significant changes in the concentration of plasma miR-210 during this type of physical activity (P = 0.73). In turn, changes in the control group were minimal. There was an increase in miR-155 expression in relation to the total training time, but the results were not statistically significant.

The study focuses on the role played by various miRNAs, namely miR-155 and miR-210, in the adaptive response of the body to exercise. The study's findings reveal that the expression of miR-155 increases upon exercise and thus can be utilized as a marker of fitness and recovery. The absence of any change in the expression of miR-210 and its inverse correlation with age and frequency of training reveals that exercise-induced epigenetic changes are complex.

Our results indicate that detailed analysis of a group of miRNAs can reveal information regarding an individual's body composition, fitness, recovery ability, and adaptations to training.