Secretion, migration and adhesion as key processes in the therapeutic activity of mesenchymal stem cells.

The MSCs are immature cells that can be found in numerous different tissue types. In recent years, they have gained considerable attention, particularly with regard to their regenerative properties. Due to their paracrine activity, ability to migrate, adhesion and homing, MSCs currently appear to be the most relevant for therapeutic use. Numerous bioactive molecules secreted by MSCs exert paracrine effects and modulate many physiological processes, such as angiogenesis, immunomodulation and neuroprotection. Cell-cell communication may be also mediated by extracellular vesicles released from the cells. Due to these properties, MSCs have been widely studied for evaluation of their therapeutic benefits expected in the clinical applications. For effective tissue regeneration, transplanted MSCs have to exit the circulation and locate at the site of damage, which is possible because of their ability to migrate, adhere and engraft at the target site. Accumulating evidence suggests that MSCs recruitment from remote sites is similar to leukocytes' migration. All of these biological features make MSCs highly investigated stem cells and the most commonly used cells in regenerative medicine. Since environmental factors affect the MSCs behavior, we discuss importance of oxygen concentration as a one of the key factors affecting MSCs properties.