Problems and prospects for the use of stem cells in transplantation

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The problems of organ and tissue transplantation are the lack of organs for transplantation and the rejection of transplants. Therefore, the issue of obtaining organs and tissues for transplantation with stem cells is being studied. Although this idea is promising, it is associated with many problems. To do this, you need to use several populations of cells on a substrate with a complex composition of nutrient environments: nutrients, growth factors, oxygen, regulatory factors. Intercellular interaction is provided by the factors they secrete, or it occurs directly with intercellular contact. This contributes to the fact that stem cells in test tubes can differentiate into other types of tissues and maintain their biological activity indefinitely, which they cannot in vivo. This approach of tissue engineering provides the possibility of obtaining whole organs for implantation. However, technical problems are associated with increased cell adhesion to plastic, the presence of a universal basis for cell nutrition, which can contain more than 100 components. There is a possibility of contamination, which can lead to serious errors in the experiment. Stem cells must have distinct mutational properties and the ability to restore telome cells. Prolonged use of the same nutrient medium can lead to genetic changes and significantly alter the physiological properties of cells. Cryopreservation can be an important aspect of the solution. The goal of tissue bioengineering is to create whole artificial organs, or at least areas of organized tissue that could be transplanted to patients. Currently, such operations are relatively simple for tissues such as artificial skin consisting of epidermal and fibroblast layers, or small cartilage implants obtained in vitro. Several cell types in stable shape are planned to be used in one environment. In this case, one type of cell can be replaced by another. This stability is provided by a variety of secreted factors by different types of cells that ensure their vitality. Decellularization removes all components involved in immune rejection of grafts, so this raises the prospect of creating an unlimited supply of organs for transplantation. However, acute reactions can develop associated with the participation of dendritic cells, macrophages, neutrophils, natural killers. Starting from the moment of transplantation, conditions for immune rejection are created, arising as a result of surgery with the development of acute inflammation. The intensity of immune reactions against the graft largely depends on the degree of non-conformity of alleles of the main complex of histocompany capacity of the donor and recipient. This match is studied using a variety of methods, including the use of antibodies or sequencing of deoxyribonucleic acid.