Acute exercise decreases insulin-stimulated extracellular vesicles in conjunction with augmentation index in adults with obesity

Extracellular Vesicles in Metabolic and Vascular Insulin Resistance

BACKGROUND

Insulin resistance is a major etiological factor in obesity, type 2 diabetes, and cardiovascular disease (CVD). Endothelial dysfunction may precede impairments in insulin-stimulated glucose uptake, thereby making it a key feature in development of CVD. However, the mechanism by which vascular tissue becomes dysfunctional is not clear.

SUMMARY

Extracellular vesicles (EVs) have emerged as potential mediators of insulin resistance and vascular dysfunction. EVs are membrane-bound particles released by tissues following cellular stress or activation. They carry "cargo" (e.g., insulin signaling proteins, eNOS-nitric oxide, and miRNA) that are believed to promote inter-cellular and interorgan communications. Herein, we review the underlying physiology of EVs in relation to type 2 diabetes and CVD risk. Specifically, we discuss how EVs may modulate metabolic (e.g., skeletal muscle, liver, and adipose) insulin sensitivity, and propose that EVs may modulate vascular insulin action to influence both endothelial function and arterial stiffness. We lastly identify how EVs may play a unique role following exercise to promote metabolic and vascular insulin sensitivity changes.

KEY MESSAGE

Gaining insight toward insulin-mediated EV mechanism has potential to identify novel pathways regulating cardiometabolic health and provide foundation for examining EVs as unique biomarkers and targets to prevent and/or treat chronic diseases.

Effects of Exercise on Extracellular Vesicles in Patients with Metabolic Dysfunction: a Systematic Review

The aim of this study was to investigate the effect of exercise on extracellular vesicles (EVs) in patients with metabolic dysfunction. The literatures were searched until Apr 28, 2022, and 16 studies that met inclusion criteria were included in this review. The results showed that the concentrations of platelet-derived extracellular vesicles (PEVs) and endothelial cell-derived extracellular vesicles (EEVs) decreased after long-term exercise, especially for CD62E⁺ EEVs and CD105⁺ EEVs. Simultaneously, exercise improved the concentration of clinical evaluation indicators of metabolic diseases, and the changes in these indicators were positively correlated with the changes of EEVs and PEVs. The concentration of skeletal muscle-derived extracellular vesicles (SkEVs) increased after a single bout of exercise. The aforementioned results indicated that long-term exercise might improve endothelial function and hypercoagulability in patients with metabolic dysfunction. The changes in concentrations of EVs could assist in assessing effect of exercise on patients with metabolic dysfunction.

Extracellular vesicles and insulin-mediated vascular function in metabolic syndrome

Metabolic Syndrome (MetS) raises cardiovascular disease risk. Extracellular vesicles (EVs) have emerged as important mediators of insulin sensitivity, although few studies on vascular function exist in humans. We determined the effect of insulin on EVs in relation to vascular function. Adults with MetS (n = 51, n = 9 M, 54.8 ± 1.0 years, 36.4 ± 0.7 kg/m2 , ATPIII: 3.5 ± 0.1 a.u., VO2 max: 22.1 ± 0.6 ml/kg/min) were enrolled in this cross-sectional study. Peripheral insulin sensitivity (M-value) was determined during a euglycemic clamp (40 mU/m2 /min, 90 mg/dl), and blood was collected for EVs (CD105+, CD45+, CD41+, TX+, and CD31+; spectral flow cytometry), inflammation, insulin, and substrates. Central hemodynamics (applanation tonometry) was determined at 0 and 120 min via aortic waveforms. Pressure myography was used to assess insulin-induced arterial vasodilation from mouse 3rd order mesenteric arteries (100-200 μm in diameter) at 0.2, 2 and 20 nM of insulin with EVs from healthy and MetS adults. Adults with MetS had low peripheral insulin sensitivity (2.6 ± 0.2 mg/kg/min) and high HOMA-IR (4.7 ± 0.4 a.u.) plus Adipose-IR (13.0 ± 1.3 a.u.). Insulin decreased total/particle counts (p < 0.001), CD45+ EVs (p = 0.002), AIx75 (p = 0.005) and Pb (p = 0.04), FFA (p < 0.001), total adiponectin (p = 0.006), ICAM (p = 0.002), and VCAM (p = 0.03). Higher M-value related to lower fasted total EVs (r = -0.40, p = 0.004) while higher Adipose-IR associated with higher fasted EVs (r = 0.42, p = 0.004) independent of VAT. Fasting CD105+ and CD45+ derived total EVs correlated with fasting AIx75 (r = 0.29, p < 0.05) and Pb (r = 0.30, p < 0.05). EVs from MetS participants blunted insulin-induced vasodilation in mesenteric arteries compared with increases from healthy controls across insulin doses (all p < 0.005). These data highlight EVs as potentially novel mediators of vascular insulin sensitivity and disease risk.

Impact of Breaking up of Sitting Time on Anti-inflammatory Response Induced by Extracellular Vesicles

Physical inactivity and sedentary behaviors (SB) have promoted a dramatic increase in the incidence of a host of chronic disorders over the last century. The breaking up of sitting time (i.e., sitting to standing up transition) has been proposed as a promising solution in several epidemiological and clinical studies. In parallel to the large interest it initially created, there is a growing body of evidence indicating that breaking up prolonged sedentary time (i.e., > 7 h in sitting time) could reduce overall mortality risks by normalizing the inflammatory profile and cardiometabolic functions. Recent advances suggest that the latter health benefits, may be mediated through the immunomodulatory properties of extracellular vesicles. Primarily composed of miRNA, lipids, mRNA and proteins, these vesicles would influence metabolism and immune system functions by promoting M1 to M2 macrophage polarization (i.e., from a pro-inflammatory to anti-inflammatory phenotype) and improving endothelial function. The outcomes of interrupting prolonged sitting time may be attributed to molecular mechanisms induced by circulating angiogenic cells. Functionally, circulating angiogenic cells contribute to repair and remodel the vasculature. This effect is proposed to be mediated through the secretion of paracrine factors. The present review article intends to clarify the beneficial contributions of breaking up sitting time on extracellular vesicles formation and macrophage polarization (M1 and M2 phenotypes). Hence, it will highlight key mechanistic information regarding how breaking up sitting time protocols improves endothelial health by promoting antioxidant and anti-inflammatory responses in human organs and tissues.