Mechanisms of stem cells action: reality and hypotheses

Abstract

Despite the long history of stem cells studying, the mechanisms of their action are still not fully understood. A classic example is the described non-hematological effect of hematopoietic stem cells (HSC), presumably due to the ability to transdifferentiation and cell fusion. The focus of clinical application in the field of regenerative medicine is mesenchymal stromal cells (MSC), and the understanding of the ways of implementfnion of their regenerative potential has evolved significantly. MSC were discovered and described as a structural unit of the HSC niche responsible for the repair of connective tissue through differentiation. However, it later turned out that they are a regulator of various processes in the body as a whole. These processes include anti-inflammatory, antifibrotic, and immunomodulatory effects, which are realized in various ways. Among these pathways, the paracrine mechanism has already been identified – the release of various growth factors, exosomes and microvesicles, the mechanism of direct transfer of mitochondria and other cellular organelles from cell to cell using tunneling nanotubes, the mechanism of efferocytosis. One of the latest discoveries in this field was the immunomodulatory effect of apoptotic MSC.In general, the study of the stem cells mechanisms of action is a living, developing field of science in which the last word will not be said soon.