Microparticle Responses to Aerobic Exercise and Meal Consumption in Healthy Men.

PURPOSE: Microparticles (MPs) are shed extracellular vesicles that express the pro-thrombotic tissue factor (TF). Aerobic exercise may reduce MP count and TF expression. This study investigated the impact of acute running or rest followed by standardised meal consumption on MP phenotypes and TF expression.

METHODS: 15 males (age: 22.9 ± 3.3 years; body mass: 81.9 ± 11.4 kg; V[Combining Dot Above]O2 max 54.9 ± 6.5 mL·kg·min; mean ± SD) completed 1h of running (70% V[Combining Dot Above]O2max) or rest at 9am, and consumed a standardised meal (1170 kcal, 43% CHO, 17% PRO, 40% fat) at 10:45am. Venous blood samples were taken at 9am, 10am and 11:30am. MP concentration, diameter, phenotypes and TF-expression were assessed using nanoparticle tracking analysis (NTA) and flow cytometry.

RESULTS: NTA identified no changes in MP concentration or diameter in response to time or trial. Flow cytometry revealed total MP count increased from 9am to 10am (1.62 ± 2.28 to 1.74 ± 2.61 x10/L, p = .016, effect size (η) = .105), but was unaffected by trial. TF platelet-derived MP % reduced from 9am to 10am (44.0 ± 21.2 to 21.5 ± 9.3%, p = .001, η = .582) after exercise only (control: 36.8 ± 18.2 to 34.9 ± 11.9%, p = .972). TF neutrophil-derived MP % reduced from 9am to 11:30am (42.3 ± 17.2 to 25.1 ± 14.9%, p = 0.048, η = .801) in the exercise trial only (control: 28.5 ± 15.7 to 32.2 ± 9.6%, p = .508).

CONCLUSION: Running induced a significant reduction in %TF platelet and neutrophil MP, suggesting a transient reduction in cardiovascular risk via reduced TF-stimulated thrombosis. This requires further investigation over longer time periods in cardiovascular disease populations.