A three-step approach identifies novel shear stress-sensitive endothelial microRNAs involved in vasculoprotective effects of high-intensity interval training (HIIT)
Question
Can shear-stress-sensitive endothelial miRNAs be identified from prior array studies and validated as HIIT-inducible circulating miRNAs with possible vasculoprotective functions?
Summary
This mechanistic paper combined a literature re-analysis, a young healthy human HIIT substudy, and endothelial cell experiments. Short all-out running HIIT acutely increased circulating miR-98-3p and miR-125a-5p, and cell experiments suggested endothelial shear stress can release these miRNAs; the paper does not test user-facing fitness or health outcomes.
Methodology
- Young healthy moderately trained students in the human HIIT substudy; HUVECs from 3 donors for in vitro validation.
- 52 participants.
- Indoor track running.
- Work intervals: 30 s all-out.
- Recovery: 30 s active recovery at warm-up speed.
- Intensity: Maximal speed/all-out.
- About 13.5 min including warm-up and intervals.
- 2 sessions/week.
- 4 weeks.
- Three-step mechanistic study: literature re-analysis, randomized HIIT protocol comparison, and in vitro endothelial shear-stress experiments
- miR-98-3p, miR-125a-5p, and Shear-stress miRNA candidates were tracked.
Outcomes
Acute miRNAs
Both miR-98-3p and miR-125a-5p increased immediately after HIIT at baseline and follow-up.
Overall time effect p<0.0001; combined rest vs post-exercise p<0.01.
Protocol comparison
The 4 x 30 s and 8 x 15 s protocols did not differ for these miRNA responses.
No significant group or interaction effect.
Resting miRNAs
Four weeks of HIIT did not change resting miR-98-3p or miR-125a-5p levels.
Resting levels at follow-up were not significantly different.
Shear stress
HUVEC medium levels of both miRNAs increased at 30 dyn/cm2.
Both p<0.05 compared with control after 1 h; time-series significance after 60 min.
Insights
- Use this paper as mechanistic context for vascular signaling, not as evidence of user-facing vascular benefit.
- Very short all-out running intervals can acutely alter circulating miRNA biomarkers in young healthy adults.
- The study does not justify preferring 4 x 30 s over 8 x 15 s for practical outcomes.
Limitations
- Mechanistic biomarkers rather than clinical or fitness outcomes
- Young healthy Caucasian sample
- In vitro HUVEC findings may not translate directly to whole-body outcomes
- No detailed adverse-event reporting
- Not all training sessions were monitored for miRNA response
Safety
- No intervention-related adverse events were reported.
- Fourteen participants dropped out before analysis; reasons were injury/illness not associated with the intervention and scheduling problems at retest.
- All HIIT sessions were supervised by at least one experienced trainer, and the sample was young and healthy.