Circulating Microparticles: Optimization and Standardization of Isolation Protocols and Reassessment of Their Characteristics and Functions

Microparticles (MPs) are convenient for clinical diagnosis, and have functional roles in signal transduction. Although the importance of MPs is being increasingly recognized, the diversity of isolated protocols for MPs results in a heterogeneous population of their unknown origins, even expands to uncertain functions. Here we systematically studied the composition of MPs at different centrifugal speed intervals, and found that 3000g was a critical centrifugation speed in determining new MPs composition. The platelet-derived particles accounted for more than 80% under 3000g, while only about 20% in MPs obtained over 3000g. Furthermore, we found that the function of new MPs was significantly different from that of traditional ones, such as procoagulation activity, anti-inflammation and clinical diagnosis etc. Thus, our work optimized the method of MPs isolation, clarified some characteristics and physiological functions that should belong to platelets rather than MPs, which will derive new conceptual MPs for its composition and function.