Abstract:

Mesenchymal stem cells（MSCs）have become a hot spot in the field of modern biology due totheir plasticity，low immunogenicity，immune regulation and self⁃renewal ability，and in numerous researches onbody injury repair，tissue function reconstruction，immune regulation and gene therapy. However，the problems ofstem cell therapy still exist，such as safety，low rate of survival，differentiation and less homing quantity，and thereis also a risk of tumorigenesis. Meanwhile，many studies have found that MSCs play their role of repair，regulationand treatment mainly through paracrine mechanism. Extracellular vesicles（EVs）secreted by MSCs not only retainthe biological activity of parental MSCs，and show similar therapeutic potential，but also compensate for someshortcomings in stem cell therapy. Therefore，MSCs⁃derived extracellular vesicles（MSC⁃EVs）have gained wideattention in many fields. In this article，the paracrine role of MSCs and its latest research progress and clinicalapplication in myocardial repair，respiratory system，immune regulation and other fields are reviewed.

Key words:

mesenchymal stem cells, paracrine action, extracellular vesicles, research advance, clinical application