Plasma microRNA levels differ between endurance and strength athletes

Area of Science:

• Exercise physiology
• Molecular biology
• Biomarkers

Background:

• MicroRNAs (miRNAs) are stable in circulation and implicated in inter-organ communication.
• Exercise training induces metabolic responses involving gene expression changes.
• The role of circulating miRNAs (c-miRNAs) in differentiating training modalities is unknown.

Purpose of the Study:

• To investigate differences in c-miRNA levels between endurance athletes, strength athletes, and untrained controls.
• To explore associations between c-miRNA levels and performance-related phenotypes.

Main Methods:

• Plasma samples from elite male endurance athletes (END, n=10), strength athletes (STR, n=10), and controls (CON, n=10) were analyzed.
• Levels of 14 candidate c-miRNAs were measured using quantitative assays.
• Regression analyses examined relationships between c-miRNAs and performance metrics.

Main Results:

• Significant differences in miR-222 levels were observed across the three groups (p=0.028).
• Endurance athletes showed higher levels of miR-222, miR-21, miR-146a, and miR-221 compared to strength athletes.
• Associations were found between c-miRNA levels and strength performance, independent of muscle or fat mass.

Conclusions:

• Specific c-miRNAs (miR-222, miR-21, miR-146a, miR-221) distinguish between endurance and strength training.
• These c-miRNAs show potential as biomarkers for exercise training modality and adaptations.
• c-miRNA levels appear unrelated to muscle bulk or fat reserves in this context.