Small extracellular vesicles (SEV) are secreted into circulation after acute exercise suggesting a new mode of tissue crosstalk. High intensity interval training (HIIT) leads to improved insulin sensitivity and oxidative capacity in patients with type 2 diabetes. As the impact of HIIT on SEV release is unknown, this study examined its effects on number and proteome of SEV in insulin sensitive (IS) and insulin resistant (IR) humans to identify biomarkers for the early prediction of individual responses of insulin sensitivity to exercising.

Eight T2D, 8 glucose tolerant IR and 6 IS humans with similar age and BMI (HbA1c in %: 7.4 ± 0.4, 5.3 ± 0.1, 5.5 ± 0.1; M-value in mg*kg-1*min-1: 1.8 ± 0.4, 4.1 ± 0.4, 7.2 ± 0.5) performed a 12-weeks HIIT cycling protocol for 3 days/week. Before the intervention (baseline) and 72 h after the last exercise bout, whole-body insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamps and serum samples were collected to isolate SEV by size exclusion chromatography. SEV size and number were measured by Nanoparticle Tracking Analysis and proteomic profiling was done by mass spectrometry using data independent acquisition. After 12 weeks of HIIT, T2D and IR improved their insulin sensitivity (M-value: T2D 3.5 ± 0.8, IR 6.2 ± 0.7; p<0.01 vs. baseline) and increased the number of circulating SEV by 52 ± 19% and 58 ± 21% (p<0.05 vs. baseline). Quantitative proteomic analysis of SEV revealed that HIIT regulated 258 proteins (118 in T2D, 125 in IR, 89 in IS) with an enrichment of proteins related to glycolysis in T2D, to antioxidative metabolism in IR and to lipid metabolism in IS.

In conclusion, HIIT increases SEV number, but differently affects SEV mass and proteome in IS and IR humans, suggesting that SEV cargo could contribute to the individual response of insulin sensitivity to HIIT. Detailed characterization of SEV cargo can help to better understand the mechanisms of tissue crosstalk in the adaptation to exercise training and to develop novel exercise mimetics.


L. Mastrototaro: None. M. Apostolopoulou: None. S. Hartwig: None. D. Pesta: None. K. Strassburger: None. E. DeFilippo: None. Y. Karusheva: None. S. Gancheva: None. D.F. Markgraf: None. S. Lehr: None. K. Mussig: None. H. Al-Hasani: Consultant; Self; Bayer AG. J. Szendroedi: None. M. Roden: Advisory Panel; Self; Servier. Board Member; Self; Poxel SA. Consultant; Self; Eli Lilly and Company, Gilead Sciences, Inc., ProSciento, TARGET PharmaSolutions. Research Support; Self; Boehringer Ingelheim International GmbH, Novartis Pharma K.K., Sanofi US. Speaker’s Bureau; Self; Novo Nordisk A/S.

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