Effects of a 6-wk Sprint Interval Training Protocol at Different Altitudes on Circulating Extracellular Vesicles

Area of Science:

• Exercise physiology
• Biochemistry
• Molecular biology

Background:

• Extracellular vesicles (EVs), including exosome-like vesicles (ELVs), are crucial in intercellular communication.
• Sprint interval training (SIT) is a potent exercise modality with known physiological effects.
• Altitude exposure significantly impacts physiological responses to exercise.

Purpose of the Study:

• To investigate the impact of 6 weeks of SIT on circulating ELVs at sea level and varying altitudes (2000, 3000, 4000 m).
• To analyze changes in ELV concentration, markers, and microRNA (miRNA) cargo following SIT under normoxic and hypoxic conditions.

Main Methods:

• Thirty trained male athletes underwent a 6-week SIT program at sea level or simulated altitude.
• Plasma ELVs were isolated using size exclusion chromatography and quantified via nanoparticle tracking analysis.
• Candidate ELV miRNAs were measured using real-time polymerase chain reaction.

Main Results:

• SIT tended to increase circulating ELVs at sea level but not in hypoxia.
• ELV markers (TSG101, HSP60) showed a trend of increase at sea level, but not under hypoxia.
• Hypoxia modulated specific miRNA levels (miR-23a-3p, miR-21-5p) within ELVs, while sea level training did not.

Conclusions:

• Sprint interval training influences circulating ELVs differently depending on altitude.
• Hypoxic conditions appear to specifically modulate the miRNA cargo of ELVs.
• Further research is needed to understand the origin and functional implications of ELVs in normoxic versus hypoxic environments.