STEM CELLS AND THEIR PARACRINE FACTORS

The literature review is devoted to the analysis of paracrine factors of stem cells of various origins. Emphasis is placed on the fact that the synthesis and secretions of trophic factors is characteristic not only of stem cells, but also of other cells of the body, such as cells of the liver, lungs, kidneys, both healthy and pathologically changed, for all these factors, which are produced by different cells, the proposed genetic name is cellular secretion, which qualitativelyand quantitatively differs depending on the type of producers of these factors. In parallel, concept of the “secretome“, which is widely used in the literature, also includes such names as conditioned environments. Humoral factors, trophic factors and exosomes. The broadest all-encom-passing term can be “secretome”, which can be characterized by different composition and activity and which can be understood as those substances that are needed by the cell for intercellular communication and interaction with other cells. The effect of the secretome on target cells and the characteristic production of humoral factors with significant trophic, stimulating properties, which contain a large number of growth factors, cytokines, and chemokines, which determine their use in pathology, are described. The specified features of the composition of the secretome, which is secreted by stem cells, depends on many conditions, such as: the origin of stem cells and the number of passages, conditions and environment of cultivation, duration of action of external factors, such as hypoxia, temperature and others. Unresolved questions were raised regarding secretome receipt and their application. It is believed that trophic factors, including the secretome of stem cells, are characterized by multidirectional mechanisms of influence on target cells, among which the following can be distinguished: stimulating proliferation and inhibiting apoptosis, immunosuppressive and immunostimulating, etc.