An Oral Glucose Load Decreases Post-Prandial Microparticles in Obese Adults With and Without Prediabetes

Microparticles (MPs) are a novel mediator and/or biomarker of cardiovascular disease (CVD) and type 2 diabetes. A high fat meal can elevate MP release in relation to CVD risk, but the effects of carbohydrates are unknown. This is clinically relevant as low-fat diets are advised for glycemic control. We tested the hypothesis that a 75g oral glucose tolerance test (OGTT) would promote changes in MPs linked to CVD risk. Twenty-five obese adults (Age: 52.4±3.2y, BMI: 32.5±1.2kg/m²) were screened for prediabetes using ADA criteria (75g OGTT and/or HbA_1c). Eight were normal glucose tolerant (NGT) and 17 had prediabetes (PD). Body composition (bioelectrical impedance) was measured and arterial stiffness (augmentation index; AI), insulin and glucose were collected at 0 and 2 hour of the OGTT to assess CVD risk. Annexin V+ (AV+) and Annexin V- (AV-) total MPs and platelet MPs (CD31⁺/CD41⁺; CD41⁺) were also collected at these times and analyzed from fresh plasma via imaging flow cytometry. There were no statistical differences in age, BMI, or body fat (all P>0.21) between NGT and PD, although fasting and 2 hour glucose as well as insulin were higher in PD vs. NGT (P<0.03). Glucose and insulin increased during the OGTT (both P≤0.005), while arterial stiffness at 2 hour decreased by 6.9% (P=0.06). Fasting MPs were not different between groups. Total MPs, AV+ CD41⁺ and AV+ CD31⁺/CD41⁺ MPs decreased after the OGTT (P≤0.04), while AV- CD41⁺ (P=0.08) and CD31⁺/CD41⁺ (P=0.10) trended. Attenuated OGTT insulin responses were related to lower post-prandial platelet AV- CD31⁺/CD41^- (r=0.46, P=0.06) and AV- CD41⁺ (r=0.45, P=0.06) MPs, while arterial stiffness was associated with reduced total MPs (r=-0.49, P=0.03) and AV+CD41⁺ (r=-0.52, P=0.02). An oral glucose load lowers post-prandial total and platelet MPs in obese adults with NGT and PD. Further work is required to examine MP content in order to gain mechanistic insight for optimizing type 2 diabetes management.