© 2018 Elsevier Masson SAS. All rights reserved. Over the past years, cell therapy has been progressively recognized as a possible therapeutic option for several and different diseases. However; whereas its mechanism of action was initially considered to be the replacement of the dysfunctional host cells by the grafted ones, it is now increasingly admitted that the therapeutic benefit is predominantly paracrine and thus mediated by the release of cell-derived factors and the subsequent activation of endogenous repair pathways. Most of these factors are clustered in extracellular vesicles which are nanoparticles secreted by all the cells in the body and play a key role in intercellular communication. Several studies have shown that the benefits of cells could be recapitulated by the vesicles they release, thereby paving the way for an a-cellular therapy whereby cells are no longer directly transplanted but serve as in vitro producers of the secretome underpinning their effects and which would thus become the therapeutic product delivered to the patient. Even though several translational issues still need to be addressed, the practical advantages of these biological medicines over their parent cells make likely that they will find a place in the armamentarium of therapies aimed at tissue repair;.