Haematopoietic stem cells have been identified at defined stages of embryonic development and several subsets have been characterised in adult haematopoiesis. Haematopoietic stem cells are rare cells with characteristics of pluripotency and self-renewal that are capable of generating an entire haematopoeitic system. Current and future research will continue to focus on the identification of haematopoietic stem cell regulators and methods for in vitro and in vivo stem cell manipulation, including genome editing, to expand the scope, potential and safety of therapy using haematopoietic stem cells. Human allogeneic stem cell therapy relies on these functional characteristics of haematopoietic stem cells that can be isolated from peripheral blood, bone marrow or cord blood, with the additional requirement that immunological barriers need to be overcome to allow sustained engraftment while minimising risk of graft-versus-host disease developing in the recipient of transplanted stem cells. The key haematopoietic stem cell characteristics of pluripotentiality and the ability for self-renewal have emerged as characteristics of several haematopoietic stem cell populations, including those that have recently challenged the conventional concepts of the haematopoietic hierarchy. Using functional assays along with evolving techniques for isolation of haematopoietic cells, haematopoietic stem cell populations were able to be enriched and their characteristics analysed. The identification of adult bone marrow as a source of haematopoietic cells capable of protecting an organism from otherwise lethal irradiation led to the intense search for their identity and characteristics.
Future studies should explore the role of MSCs in differentiation, transplantation, and immune response in various diseases.The discovery and characterisation of haematopoietic stem cells has required decades of research. The multipotent properties of MSCs make them an attractive choice for possible development of clinical applications. One of the major challenges is to elucidate the mechanisms of differentiation, mobilization, and homing of MSCs, which are highly complex. There are likely more sources of MSCs waiting to be discovered, and MSCs may be a good candidate for future experimental or clinical applications. Recently, MSCs have been found in new sources, such as menstrual blood and endometrium.
This is because the ease of harvest and quantity obtained make these sources most practical for experimental and possible clinical applications. MSCs can be isolated from a variety of tissues, such as umbilical cord, endometrial polyps, menses blood, bone marrow, adipose tissue, etc. Mesenchymal stem cells (MSCs) are stromal cells that have the ability to self-renew and also exhibit multilineage differentiation. The use of adult mesenchymal stem cells is less problematic with regard to these issues. Embryonic stem cells (ESC) are obtained from the inner cell mass of the blastocyst and are associated with tumorigenesis, and the use of human ESCs involves ethical and legal considerations. Two major types of stem cells have been described, namely, embryonic stem cells and adult stem cells. Stem cells have two features: the ability to differentiate along different lineages and the ability of self-renewal.
0 kommentar(er)
