199-OR: Insulin Infusion Decreases Extracellular Vesicles in Adults with Metabolic Syndrome

Elevated extracellular vesicles (EVs) are associated with glucose dysmetabolism. However, the direct effects of insulin on EVs and subsequent relationship with insulin sensitivity and substrate oxidation is unknown in adults with metabolic syndrome (MetS). Fifty sedentary adults (54.5 ± 1.0 yr; VO2peak: 22.3 ± 0.6 ml/kg/min) with MetS (36.3 ± 0.7 kg/m2; ATP III Criteria: 3.46 ± 1.0) underwent a 2-hr euglycemic-hyperinsulinemic clamp (90 mg/dl; 40 mU/m2/min) to determine EV responses to insulin and metabolic insulin sensitivity (M-Value). Endothelial (CD105+, CD41-/CD31+), leukocyte (CD45+), platelet (CD41+, CD41+/CD31+), and tetraspanin-derived EVs (TX+), as well as platelet endothelial cell adhesion molecule (CD31+) were detected in platelet poor plasma samples at 0 and 2-hr of the clamp using spectral flow cytometry. Fat (Fox) and carbohydrate oxidation (CHOox) were also measured (indirect calorimetry) to determine metabolic flexibility. Despite low metabolic insulin sensitivity (2.55 ± 0.2 mg/kg/min), insulin (82.9 ± 3.7 uU/ml) reduced Fox (delta, P=0.001) compared to fasting. Insulin also decreased CD105+ (P Disclosure E. Heiston: None. A. Ballantyne: None. N. Stewart: None. L. Musante: None. U. Erdbruegger: None. S. K. Malin: None. Funding National Institutes of Health (R01HL130296)