Abstract
PurposePhysical activity is associated with altered levels of circulating microRNAs (ci-miRNAs). Changes in miRNA expression have great potential to modulate biological pathways of skeletal muscle hypertrophy and metabolism. This study was designed to determine whether the profile of ci-miRNAs is altered after different approaches of endurance exercise.MethodsEighteen healthy volunteers (aged 24 ± 3 years) participated this three-arm, randomized-balanced crossover study. Each arm was a single bout of treadmill-based acute endurance exercise at (1) 100% of the individual anaerobic threshold (IANS), (2) at 80% of the IANS and (3) at 80% of the IANS with blood flow restriction (BFR). Load-associated outcomes (fatigue, feeling, heart rate, and exhaustion) as well as acute effects (circulating miRNA patterns and lactate) were determined.ResultsAll training interventions increased the lactate concentration (LC) and heart rate (HR) (p < 0.001). The high-intensity intervention (HI) resulted in a higher LC than both lower intensity protocols (p < 0.001). The low-intensity blood flow restriction (LI-BFR) protocol led to a higher HR and higher LC than the low-intensity (LI) protocol without BFR (p = 0.037 and p = 0.003). The level of miR-142-5p and miR-197-3p were up-regulated in both interventions without BFR (p < 0.05). After LI exercise, the expression of miR-342-3p was up-regulated (p = 0.038). In LI-BFR, the level of miR-342-3p and miR-424-5p was confirmed to be up-regulated (p < 0.05). Three miRNAs and LC show a significant negative correlation (miR-99a-5p, p = 0.011, r = − 0.343/miR-199a-3p, p = 0.045, r = − 0.274/miR-125b-5p, p = 0.026, r = − 0.302). Two partial correlations (intervention partialized) showed a systematic impact of the type of exercise (LI-BFR vs. HI) (miR-99a-59: r = − 0.280/miR-199a-3p: r = − 0.293).ConclusionMiRNA expression patterns differ according to type of activity. We concluded that not only the intensity of the exercise (LC) is decisive for the release of circulating miRNAs—as essential is the type of training and the oxygen supply.
Highlights
MicroRNAs are small, non-coding, singlestranded, endogenously encoded RNAs consisting of approximately 20–24 nucleotides
No other systematic correlation between lactate concentration and miRNA expressions occurred. In this three-armed crossover study, we investigated the miRNA profiles elicited by three different acute single bout of acute endurance exercise interventions without or with peripheral blood flow application (HI, LI, LI-blood flow restriction (BFR)) in young, healthy athletes
It has been reported that miR-424-5p regulates hypoxia-inducible factor (HIF)-α isoforms and promotes angiogenesis (Ghosh et al 2010). This is in line with our observation that only blood flow restriction exercise stimulated the expression of this particular miRNA
Summary
MicroRNAs (miRNAs) are small, non-coding, singlestranded, endogenously encoded RNAs consisting of approximately 20–24 nucleotides. There are positive correlations with other exerciseassociated parameters such as peak workload, serum creatine kinase (skeletal muscle damage) or changes in levels of high-sensitivity C-reactive protein (an acute-phase inflammatory marker) and miR-221 and miR-146a (Li et al 2018). It appears that many miRNAs can adapt to a specific training type. The traininginduced change in miRNA expression is a probable muscular adaptation mechanism in response to endurance training Another example is miRNA-486 which up-regulates insulin-dependent glucose uptake in metabolic tissues, such as skeletal muscles. Our hypothesis is: lowintensity blood flow single bout of acute endurance exercise and exercise without blood flow restriction lead to different expression patterns of miRNAs
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