Update on extracellular vesicles inside red blood cell storage units: Adjust the sails closer to the new wind.

Release of vesicles from cells is a universal biological system, an adaptive cellular response to endogenous or external physiological or stressful stimuli and a genius means for intercellular, inter-organ and even inter-organism communication. These secreted vesicles that are collectively designated extracellular vesicles (EVs) have increasingly attracted the interest of cell biologists due to their imaginable interactions with every piece of the known biological systems in both health and disease states. Although EVs isolation and characterization are challenges, owing to their particular physicochemical features and complex biology, recent technological innovation has offered better understanding and inevitably, driven the revision of previously established theories on them. However, a crucial question remains unsolved: the physiological relevance of EVs in vivo. Since membrane vesiculation is an integral part of red blood cell (RBC) aging and homeostatic machinery and a prominent feature of RBC storage lesion, the characterization of storage EVs and their probable clinical relevance with the therapeutic or adverse effects of transfusions are extremely important targets in the research fields of transfusion biology and medicine. The scientists involved should transfer nascent knowledge and state-of-the-art technological tools in the packed RBC unit in order to: (i) update the inventory of biochemical and biophysical features of storage EVs; (ii) gain insight into the molecular pathways/signals underlying their generation; and (iii) clarify their dependence on blood donor, storage strategies and analytical variations, in order to step forward on understanding their interactions with stored or recipient target cells.