Elevated Levels of VE-Cadherin-Positive Endothelial Microparticles in Patients With Type 2 Diabetes Mellitus and Coronary Artery Disease

OBJECTIVES: The purpose of this study was to examine whether CD144-EMP (endothelium-derived microparticles) is useful as a specific marker of endothelial cell (EC) dysfunction and to determine whether plasma levels of circulating CD144-EMP predicted coronary artery disease (CAD) in patients with type 2 diabetes mellitus (DM). BACKGROUND: Endothelial cell dysfunction is involved in atherogenesis; however, the quantitative assessment of EC dysfunction has yet to be established clinically. Endothelium-derived microparticles are small, membrane-shed vesicles that are generated from the EC surface in response to cellular dysfunction and/or injury. Diabetes mellitus is known to be associated with EC dysfunction and accelerated atherosclerosis. METHODS: We characterized EMP using anti-CD144 (VE-Cadherin) antibody in various atherosclerosis-related cells and investigated the association between the levels of CD144-positive microparticles and hydrogen-peroxide-induced EC injury and acetylcholine-induced coronary vasomotion. Furthermore, we evaluated plasma CD144-EMP levels in patients with and without DM. RESULTS: We demonstrated that CD144-positive microparticles were derived selectively from human EC. The levels of CD144-EMP reflected the degree of in vitro hydrogen-peroxide-induced EC injury and impairment of in vivo endothelium-dependent coronary vasodilation (p < 0.01). Plasma CD144-EMP levels were increased significantly in DM patients compared with patients without DM (p < 0.001). In DM patients, the elevated levels of CD144-EMP were the most significant risk factor for CAD relative to all other traditional risk factors (odds ratio [OR] 3.5, 95% confidence interval [CI] 1.8 to 6.9, p < 0.001). Notably, plasma CD144-EMP identified a subpopulation of established CAD patients in DM subjects without typical anginal symptoms (OR 10.6, 95% CI 3.9 to 29.5, p < 0.001). CONCLUSIONS: The CD144-positive EMP exist in human plasma, and plasma CD144-EMP levels can be a clinically specific and quantitative marker of EC dysfunction and/or injury. Measurement of CD144-EMP, by providing a quantitative assessment of EC dysfunction, may be useful for identifying DM patients with increased risk of CAD.