The new composition of circulating microvesicles: optimized protocols and reassessment of their characteristics and physiological functions.

Microvesicles (MVs) have convenient clinical applications and play functional roles in cellular signal transduction. Although the clinical importance of MVs is being increasingly recognized, the current diversity of isolated protocols results in a heterogeneous population of their unknown origins, even expands to uncertain functions. Here, we systematically investigated the composition of MVs at different centrifugal speed intervals and discovered that centrifugation at 3000 g is critical in determining the composition of MVs. We observed that platelet-derived particles accounted for more than 80% of MVs under 3000 g, while only about 20% of MVs were obtained over 3000 g. The discovery that more than 80% of platelet-derived MVs sheds new light on their function, including procoagulation activity and clinical diagnosis, etc. Our work not only optimizes the method for MVs isolation but also clarifies the physiological functions and characteristics that should be attributed to platelets rather than MVs. Consequently, these findings will derive new conceptualizations regarding MVs' composition and function.