Type 2 diabetes and older age contribute to elevated plasma microparticle concentrations independent of chronic stroke

The elevated circulating concentration of endothelial microparticles (MPs) may provide an index of the extent and nature of cellular damage in chronic stroke. The purpose of this study was to determine the circulating concentrations of CD31(+)/CD42b(-), CD62E(+) and CD34(+) MPs in chronic stroke subjects, focusing on the effects of chronic stroke by comparison with both older adults without a history of stroke but with type 2 diabetes mellitus (T2DM) and older and young healthy controls. Plasma from three groups of sedentary older (50-75 years) men and women (chronic stroke, T2DM or older healthy) as well as a group of younger (18-39 years) healthy controls was isolated from fasting blood, and CD31(+)/CD42b(-), CD62E(+) and CD34(+) MPs were quantified using flow cytometry (n = 17/group). Concentrations of CD31(+)/CD42b(-) and CD62E(+) MPs were higher in the T2DM group (P < 0.05), but not chronic stroke, compared to older and younger healthy adults. CD62E(+) MP and CD34(+) MP concentrations were elevated in the older compared to younger adults (P < 0.05 for both). Sub-analyses excluding chronic stroke subjects who were also diagnosed with diabetes [stroke (diabetes(-))] revealed lower CD31(+)/CD42b(-) (P < 0.05) and CD62E(+) (P = 0.08) MPs in the stroke (diabetes(-)) group compared to the T2DM group. CD31(+)/CD42b(-) MP and CD62E(+) MP concentrations were each associated with fasting glucose levels and CD31(+)/CD42b(-) MPs also were associated with triglyceride levels. As MPs have been proposed as potential targets for diagnosing, treating and identifying the clinical progression of T2DM, our study provides further support for the use of CD31(+)/CD42b(-) and CD62E(+) MPs in the clinical progression of T2DM and associated vascular complications.