Blood Dust as Active Circulating Cellular Representatives During Gestational Vascular Complications

Abstract

See related article, p 893–898 History sometimes repeats itself. Alfred Donne was probably the first to recognize platelets in the blood in 1842, and Schultze associating the platelets to clotting later on in 1865, but actually, hemoconia (blood dust), devoid of a nucleus, was probably seen by earlier microscopists without any thought being given to their significance. In fact, looking closely at modern electron microscopic pictures of blood, the background between platelets is filled with blood dust, whose significance has been ignored for a while. Minute particles in normal human plasma and serum were first described by Wolf,1 who found this material containing most of the platelet-related coagulant activity of plasma and serum. This progressively led to the identification of heterogeneous cell–derived, extracellular vesicles in human body fluids, which generally express cell surface antigens representative of their parent cells, which contain a phospholipid bilayer and have diameters ranging from 50 nm to 5 µm.2 Among microvesicles (MVs), microparticles (MPs) are generally defined as small vesicles, with a diameter of 100 to 1000 nm, resulting from the blebbing of the cellular membrane during activation or apoptosis processes, different from exosomes that have diameter of <100 nm and are stored intracellularly in multivesicular bodies, and from apoptotic bodies, that is, larger fragments resulting from the late stages of apoptosis.3 Evidences accumulated in the literature now indicate that this initially inert blood dust constitute in fact a myriad of bioactive circulating principles that …