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Term: Stem Cell Technologies & HIT

Description:

Stem cell technology offers hope of effective treatment for a variety of diseases that are malignant and non-malignant. This rapidly developing field combines the efforts of cell biologists, geneticists, and clinicians.


What is a Stem Cell?


Stem cells are biological cells found in all multicellular organisms, that can divide (through mitosis) and differentiate into diverse specialized cell types and can self-renew to produce more stem cells. In mammals, there are two broad types of stem cells: embryonic stem cells, which are isolated from theinner cell mass of blastocysts, and adult stem cells, which are found in various tissues. In adult organisms, stem cells and progenitor cells act as a repair system for the body, replenishing adult tissues. In a developing embryo, stem cells can differentiate into all the specialized cells (these are called pluripotent cells), but also maintain the normal turnover of regenerative organs, such as blood, skin, or intestinal tissues.

Applications of cultured haematopoietic stem cells:

Haematopoietic stem cells are a somatic cell population with highly specific homing properties and are capable of self renewal and differentiation into multiple cell lineages.2 Human haematopoietic progenitor cells, like stromal cell precursors in bone marrow, express the CD34 antigen, a transmembrane cell surface glycoprotein identified by the My10 monoclonal antibody.3 However, pluripotent stem cells constitute only a small fraction of the whole CD34+ population, which is by itself rather heterogeneous regarding phenotype and function. The best way to define haematopoietic stem cells is from their functional biology. They are known to restore multilineage, long term haematopoietic cell differentiation, and maturation in lethally cytoablated hosts.4 Haematopoietic stem cells can be obtained from bone marrow, peripheral blood,5 umbilical cord blood,6 and fetal liver.7

The use of peripheral blood stem cells in both autologous and allogeneic transplantation has become routine as they can be collected on an outpatient basis and also promote a consistent acceleration in haematopoietic reconstitution after engraftment.8 Umbilical cord blood stem cells have been used progressively in paediatric patients, from both related and unrelated HLA-matched donors. In recipients with severe T cell immunodeficiency disorders, fast engraftment is required together with a low risk of graft versus host disease and a low viral transmission rate.9 Since umbilical cord blood stem cells can be expanded in vitro or frozen for storage in cell banks10 they have been used in clinical trials for both autologous and allogeneic haematopoietic stem cell transplantation.11

Applications of non-haematopoietic stem cells:

Embryonic stem cells were first isolated in 1981 through studies focusing primarily on murine blastocysts.32 Embryonic stem cells are derived from totipotent cells of the early mammalian embryo and are capable of unlimited, undifferentiated proliferation in vitro.33 Human embryonic stem cells can express high levels of telomerase activity, comparable with that expressed by cells isolated from germ lines and embryonic tissues.34 They can also form several cell types and simple tissue. Further understanding of cell tissue interactions and their relation with the extracellular matrix may eventually enable in vitro production of complex organs.35 In vitro manipulation of embryonic stem cells can be enhanced by nuclear transfer and cloning.36

Initial clinical trials have shown that neurone replacement for neurovegetative diseases such as Parkinson's and Huntington's diseases is now feasible. Reports of transplantation of fetal striatal tissue in patients with mild to severe Huntington's disease suggest that transplantation of neuronal stem cells may improve some of the cognitive symptoms associated with the condition, as well as potentially modifying its clinical course.41 Neuronal stem cells can also be manipulated before grafting; they have been shown to respond to stimulation with fibroblast growth factor-2, and immortalised neural stem-like cells infected with viral vectors have been found to express factors that are related to neural repair.42

Stem Cell Treatment:

It is believed by medical researchers that stem cell therapy can significantly change the treatment of human disease. Some adult stem cell therapies already exist, such as bone marrow transplants that are used to treat leukemia. Medical researchers anticipate being able to use technologies derived from stem cell research to treat a wider variety of diseases such as cancer, Parkinson's disease, spinal cord injuries, Amyotrophic lateral sclerosis, multiple sclerosis, and muscle damage, amongst a number of other conditions. However, there is still a lot of uncertainty surrounding stem cell research, which could possibly be overcome through public debate and future research, and further education of the public.



Web Resources:









Related Terminology:

Stem Cell Research - Stem cell research is a developing technology that focuses on using undifferentiated cells therapeutically to treat human disease and injury.

Bone Marrow - The sponge-like tissue found in the center of certain bones which contains stem cells that are the precursors of white blood cells, red blood cells, and platelets.

Cancer - An abnormal growth of cells which tend to proliferate in an uncontrolled way and, in some cases spread.

Adult Stem Cells - Stem cells found in different tissues of the developed, adult organism that remain in an undifferentiated, or unspecialized, state.

Cloning - In biology, the process in which an organism produces one or more genetically identical copies of itself by asexual means.

Interesting Articles:

Key Innovations in Stem Cell Technology
Stem Cells From Monkey Teeth Can Stimulate Growth And Generation of Brain Cells
Belarus, Russia to Build Clinic Providing Stem Cell Treatments in Minsk



Citations/References:

Wikipedia
Pub Med Central
http://www.isscr.org/Glossary_of_Stem_Cell_Related_Terms.htm


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