**Author details**

damaged cells and generate new healthy cells. The rapid progress in MSC research and the primary function in cellular niches under normal and pathological physiological conditions and the management of cellular intercommunication of the microenvironment through the paracrine secretion and their biological products are being incorporated into

The initial paradigm of cellular therapy for tissue and organ repair and regeneration has been modified, with new knowledge from experimental, preclinical, and clinical studies related to the mechanism of action of MSCs both *in vivo* and *in vitro*, which have demonstrated to be processes fundamentally of paracrine action, by means of the generation of exosomes,

Recently, a group of secreted vesicles, the "exosome", has been identified as the main mediator of the therapeutic efficacy of MSC. The ExMV participate in intercellular, local, and remote communication, which are translated into pleiotropic actions and generate a therapeutic potential by transferring biologically active molecules and which can be used as new biomarkers and potential regulators of inflammation and immune response to detect immune rejections. Exosome/microvesicle therapy derived from MSCs has potential advantages. First, it prevents the transfer of cells that may have mutated or damaged DNA. Second, the vesicles are small and easily circulated, while the MSCs are too large to easily circulate through the capillaries and many do not even reach the first capillary bed. Third, the dose of MSC decreases rapidly after transplantation, but the administration of the biological products of the cells allows higher therapeutic "doses". The disadvantage of using vesicles derived from MSCs is that they are static and cannot occur more when they are transplanted. The therapeutic efficacy of MSCs is based on their ability to respond in the microenvironment of the lesion, whereas the isolated exosomes are not expected to do so. The opportunity to exploit the potential therapy of MSCs and their products opens new scenarios for the identification of new molecules for the repair and regeneration of organs and tissues through proteome

In the short term, the exosomes derived from MSCs will progress to clinical studies, and their usefulness and effectiveness will depend on establishing a series of critical parameters such as standardizing reproducible production methods for the manufacture of exosomes/microvesicles with precisely defined content, standardizing storage methods that maintain their potency, and evaluating therapeutic efficacy in controlled clinical trials, of appropriate power, designed with written criteria and with solid research foundations to generate scientific results that allow the translation of basic knowledge to create new

No conflicts of interest, financial or otherwise, are declared by the authors.

microvesicles, and the horizontal transfer of proteins, mRNA, and microRNA.

clinical practice.

200 Stromal Cells - Structure, Function, and Therapeutic Implications

analysis of the secretome.

regenerative therapies.

**Conflict of interest**

Daniel Ascencio González1 \*, Rogelio Hernández Pando<sup>2</sup> , Miguel Ángel Gómez Lim3 , Sergio Ayala Fraustro4 and Aaron Torres Garcia<sup>5</sup>

\*Address all correspondence to: danielascencio@gmail.com

1 Facultad Mexicana de Medicina, Hospital Angeles del Pedregal, La Salle University, Mexico City, Mexico

2 Experimental Pathology Unit, Instituto Nacional De Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico

3 Center for Research and Advanced Studies of the National Polytechnic Institute, Cinvestav, Mexico City, Mexico

4 Hospital Angeles Mexico, Mexico City, Mexico

5 Hospital ABC, Mexico City, Mexico
