Mother cells: their history
Introduction
The current understanding of clonal stem cell populations has only been validated in the last 40 years. Before the 1960s it was believed that all dividing cells contributed to the growth and renewal of tissues, and in general they were classified as resident stem cells. However, a revolutionary publication in 1961 redefined the existing perceptions of stem cells by isolating a specific population of self-rising cells in the bone marrow.
This particular stem cell population was discovered by infusing a lethally irradiated mouse with bone marrow cells capable of migrating to the spleen and giving rise to the nodules of hematopoietic cells. It was then demonstrated that the cells of the nodules came from a single cell. Cells capable of giving rise to clonal populations were called ‘colonies forming units’ and, finally, it was demonstrated that they were short -term hematopoietic cells.
Developing
Studies like this provided the framework for our current understanding of the undifferentiated self-river cell population. The presence of mesenchymal stem cells, an adult stem cell type, in the bone marrow was first suggested at the end of the 19th century by Cohneim, who proposed that the fibroblasts involved in the healing of peripheral wounds derived from the medulla compartment .
In the 1970s, Friedenstein et al. It demonstrated the existence of ‘fibroblastoid’ cells inside the bone marrow of an Indian bunny by washing cells in plastic culture plates and the discard of non -adherent cells. The remaining fusiform cells were heterogeneous in appearance but seemed to be able to form in vitro colonies, giving rise to the term of unity fibroblasts of colonies of colonies.
When these cells were subsequently transplanted to subcutaneous bags, heterotopic bone tissue formed successfully. Using similar methods, Castro-Malaspina et al. effectively isolated the fibroblasts of the human bone marrow colonies colonies unit. Since these first studies, subsequent investigations have shown that these cells could be cultivated in vitro and differentiate themselves into various types of cells within the mesenquimal lineage.
The fundamental characterization of CMM as a population of truly multipotent cells is attributed to the work done by Pittenger and its colleagues in 1999. Before this report, the scientists were not sure whether the cmm of the bone marrow represented a heterogeneous mixture of committed parents, each of them with a restricted potential, or of individual cells capable of differentiating themselves in fat, cartilage, bone andmuscle.
The realization of human bone marrow aspirations of the iliac crest of more than 350 donors through a density gradient insulation procedure resulted in a phenotypically homogeneous population of adherent cells. The flow cytometry analysis confirmed that more than 98% of these adherent cells shared the same surface marker profile.
Individual cells of this population were isolated and expanded again. It was shown that these new descendant cells retain the ability to differentiate themselves in adipocytes, chondrocytes and osteoblasts. Therefore, it was shown that CMM have the ability to proliferate widely while maintaining their multipotent nature and identified as true stem cells.
Historically, adipose tissues were supposed to work only as a metabolic reserve responsible for the processing, storage and release of high energy materials in the form of cholesterol and triglycerides. However, in the early 1960s, scientists described a stromovascular fraction (FVS) within the adipose region.
It was shown that these new descendant cells retain the ability to differentiate themselves in adipocytes, chondrocytes and osteoblasts. Therefore, it was shown that CMM have the ability to proliferate widely while maintaining their multipotent nature and identified as true stem cells. Historically, adipose tissues were supposed to work only as a metabolic reserve responsible for the processing, storage and release of high energy materials in the form of cholesterol and triglycerides.
However, in the early 1960s, scientists described a stromovascular fraction (FVS) within the adipose region. It was shown that these new descendant cells retain the ability to differentiate themselves in adipocytes, chondrocytes and osteoblasts. Therefore, it was shown that CMM have the ability to proliferate widely while maintaining their multipotent nature and identified as true stem cells.
Historically, adipose tissues were supposed to work only as a metabolic reserve responsible for the processing, storage and release of high energy materials in the form of cholesterol and triglycerides. However, in the early 1960s, scientists described a stromovascular fraction (FVS) within the adipose region. It was shown that CMM have the ability to identify widely while maintaining their multipotent nature and knows as true stem cells.
Historically, adipose tissues were supposed to work only as a metabolic reserve responsible for the processing, storage and release of high energy materials in the form of cholesterol and triglycerides. However, in the early 1960s, scientists described a stromovascular fraction (FVS) within the adipose region.
It was shown that CMM have the ability to identify widely while maintaining their multipotent nature and knows as true stem cells. Historically, adipose tissues were supposed to work only as a metabolic reserve responsible for the processing, storage and release of high energy materials in the form of cholesterol and triglycerides.
However, in the early 1960s, scientists described a stromovascular fraction (FVS) within the adipose region. storage and release of high energy materials in the form of cholesterol and triglycerides. However, in the early 1960s, scientists described a stromovascular fraction (FVS) within the adipose region. storage and release of high energy materials in the form of cholesterol and triglycerides. However, in the early 1960s, scientists described a stromovascular fraction (FVS) within the adipose region.
The embryos produced by in vitro fertilization were obtained by Thomson and cultivated to the blastocyst stage, typically 4-5 days after fertilization. From the internal cell mass (which finally forms the embryo), five separate lines of HESC were established and they were kept successfully in cultivation for 6 months in an undifferentiated state.
The five lines retained the ability to form teratomas after injection in immunodefering mice. The histological examination of these teratomas epithelium, cartilage, bone, smooth muscle, neural epithelium, ganglia and stratified squamous epithelium. Reubinoff and his colleagues also described similar findings, who derived two additional cell lines of HESC and demonstrated the expression of the OCT-4 transcription factor in these cells in these cells.
Previously it had been shown that October 4 was essential for maintain. The development of CMEH galvanized research on human embryogenesis, the development of congenital defects and cell mechanisms of a variety of pathological states.
In theory, HESC can be used to treat a wide variety of genetic diseases, cancers, diabetes, degenerative neurological conditions and spinal cord injuries. However, real translation into clinical use has been hindered by problems with the host graft disease. A possible solution to this implies the development of several HESC cell lines of varied genetic origins for custom use in patients and minimizing the risk of rejection.
Other strategies that have been proposed include the use of adult autologous donor stem cells or the most recent IPS cell. Concerns have also emerged regarding the xenogenic pollution of stem cells during crop. The HESC are traditionally grown in vitro using mouse embryonic fibroblast feeding layers (MEF).
Without MEF feeding layers, the HESCs undergo rapid differentiation and lose pluripotence. Xu and his colleagues have presented a cultivation system without feeders that matrigel uses in medium conditioned by MEFS. However, even with this system, the HESC are still exposed to murine products to maintain pluripotence.
The fears of xenogenic pollution were corroborated in 2005, when Martin et al reported the presence of a non5gc non -human sinalic acid on the Hescs cell surface. As humans are unable to generate this particular sinalic acid, this finding probably represented the absorption of media that contain animal products and their incorporation through glycosylation. When these Hescs and their derived embryonic bodies were exposed to human serum, there was a rapid union of immunoglobulin and the deposition of the complement, which finally resulted in cell death.
conclusion
The evasion of this problem required the creation of a new line of stem cells in Murinos free conditions. To achieve this, new extracellular matrix coated plates were developed from MEFS and sterilized before use. The three embryonic germ layers. This system eliminated the HESC exposure to the potential pollution of serum and / or living feeding cells and minimized the risk of disease transmission through the contact of cells with animal or human pathogens.
When the HESCS were grown using these plates, there was an undifferentiated proliferation for 6 months and the cells maintained the ability to form the three embryonic germ layers. This system eliminated the HESC exposure to the potential pollution of serum and / or living feeding cells and minimized the risk of disease transmission through the contact of cells with animal or human pathogens.
When the HESCS were grown using these plates, there was an undifferentiated proliferation for 6 months and the cells maintained the ability to form the three embryonic germ layers. This system eliminated the HESC exposure to the potential pollution of serum and / or living feeding cells and minimized the risk of disease transmission through the contact of cells with animal or human pathogens.
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