It is known that a suspension of stem cells consist of cell populations with different sensitivities to freezing, with higher populations have krioustoychivostyu erythroid cells, and in fact GSK. At the same time, the monocyte-macrophage cells in the first place affect the direction of differentiation and proliferation rate of erythroid progenitor cell number (Kozlov, 1984).
Thus, after cryopreservation of stem cells in the suspension increases the relative content of more than krioustoychivyh populations, in particular, stem cells and hematopoietic progenitor cells of erythroid series. At the same time the ability of these cells to perceive and respond to regulatory impact monocyte-macrophage elements after cryopreservation does not change.
Therefore, the population perdshestvennikov erythropoiesis, responsive to regulatory signals emanating from the monocyte-macrophage cells after cryopreservation becomes dominant, which defines an undesirable shift in the direction of differentiation of erythroid cells. In addition, the effects of cryopreservation of HSCs may be clustering, the lateral separation of the components of membranes, changing the topography of the receptors and their partial loss, reversible changes in the properties of receptors and receptor zones, which receive regulatory signals.
Change in the physico-chemical properties of membranes can be explained by an increase in the number of adherent monocyte-macrophage cells cryopreserved HSC (up to 30-35% compared with 3-5% native adhered cells). Due to the reversibility of changes in physical-chemical properties of the membranes of cryopreserved HSC after thawing increases the share of HSC, which receive regulatory signals monocyte-macrophage elements. Nevertheless, the authors note that all the described changes of cryopreserved HSC reversible and disappear when exposure of cells both in the in vitro, and in vivo (Tsutsaeva et al, 2002).
Cytokine regulation of hematopoiesis deserves a more detailed analysis, since the maturation of progenitor cells and the release of differentiated cells in the blood is largely determined not only hematopoietic microenvironment (stromal cells of the set, located on the endosteal surface of the bone marrow cavity), but also a complex regulatory effects of cytokines, which include colony factors and interleukins. Most of them are produced by bone marrow cells and autoimmune paracrine effect.
But there are systemic endocrine regulators of hematopoiesis plan, such as thrombopoietin eritrogenin and synthesized in the kidney and liver (Vatutin et al, 2003).
Growth and differentiation of cells of all, without exception, organs and tissues of the human body are regulated by cytokines or interleukins, which is a feature of their functional pleiotropy. Every single cytokine showing a wide variety of biological effects in different tissues and cells, and many different cytokines overlap with each other on the impact of certain cells. Functional pleiotropy and redundancy effects associated with the peculiarities of the molecular organization of cytokine receptor systems (Tupitsyn, 2001).
Effects of cytokines based on their binding to specific cell membrane receptors. Receptors for growth factors early in the widely available on the surface of various cell types. Receptors for SCF (CD117) found on the surface of embryonic stem cells, stem cells of regional, partially and fully kommitirovannyh hematopoietic progenitor cells, mast cells, melanocytes, fetal neural cells (Nathan, Ziff, 1994).
In particular, the expression of VEGF receptor is the earliest marker for hemangioblasts education. It is shown that cells with a phenotype Flkl +, derived from embryonic stem cells give rise not only hematopoietic cells but also two types of cells that form the basis of blood vessels both in the in vitro, and in vivo. These data indicate for the future use of pluripotent stem cells for the construction of vascular tissue (D'Amore, 2000). In general, it appears that the fine regulation of the cellular response to cytokine stimulation depends not only on themselves cytokines, but on what receptors are expressed on the target cell at the time of regulatory impact.
Thus, after cryopreservation of stem cells in the suspension increases the relative content of more than krioustoychivyh populations, in particular, stem cells and hematopoietic progenitor cells of erythroid series. At the same time the ability of these cells to perceive and respond to regulatory impact monocyte-macrophage elements after cryopreservation does not change.
Therefore, the population perdshestvennikov erythropoiesis, responsive to regulatory signals emanating from the monocyte-macrophage cells after cryopreservation becomes dominant, which defines an undesirable shift in the direction of differentiation of erythroid cells. In addition, the effects of cryopreservation of HSCs may be clustering, the lateral separation of the components of membranes, changing the topography of the receptors and their partial loss, reversible changes in the properties of receptors and receptor zones, which receive regulatory signals.
Change in the physico-chemical properties of membranes can be explained by an increase in the number of adherent monocyte-macrophage cells cryopreserved HSC (up to 30-35% compared with 3-5% native adhered cells). Due to the reversibility of changes in physical-chemical properties of the membranes of cryopreserved HSC after thawing increases the share of HSC, which receive regulatory signals monocyte-macrophage elements. Nevertheless, the authors note that all the described changes of cryopreserved HSC reversible and disappear when exposure of cells both in the in vitro, and in vivo (Tsutsaeva et al, 2002).
Cytokine regulation of hematopoiesis deserves a more detailed analysis, since the maturation of progenitor cells and the release of differentiated cells in the blood is largely determined not only hematopoietic microenvironment (stromal cells of the set, located on the endosteal surface of the bone marrow cavity), but also a complex regulatory effects of cytokines, which include colony factors and interleukins. Most of them are produced by bone marrow cells and autoimmune paracrine effect.
But there are systemic endocrine regulators of hematopoiesis plan, such as thrombopoietin eritrogenin and synthesized in the kidney and liver (Vatutin et al, 2003).
Growth and differentiation of cells of all, without exception, organs and tissues of the human body are regulated by cytokines or interleukins, which is a feature of their functional pleiotropy. Every single cytokine showing a wide variety of biological effects in different tissues and cells, and many different cytokines overlap with each other on the impact of certain cells. Functional pleiotropy and redundancy effects associated with the peculiarities of the molecular organization of cytokine receptor systems (Tupitsyn, 2001).
Effects of cytokines based on their binding to specific cell membrane receptors. Receptors for growth factors early in the widely available on the surface of various cell types. Receptors for SCF (CD117) found on the surface of embryonic stem cells, stem cells of regional, partially and fully kommitirovannyh hematopoietic progenitor cells, mast cells, melanocytes, fetal neural cells (Nathan, Ziff, 1994).
In particular, the expression of VEGF receptor is the earliest marker for hemangioblasts education. It is shown that cells with a phenotype Flkl +, derived from embryonic stem cells give rise not only hematopoietic cells but also two types of cells that form the basis of blood vessels both in the in vitro, and in vivo. These data indicate for the future use of pluripotent stem cells for the construction of vascular tissue (D'Amore, 2000). In general, it appears that the fine regulation of the cellular response to cytokine stimulation depends not only on themselves cytokines, but on what receptors are expressed on the target cell at the time of regulatory impact.
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