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adult_stem_cells [2018/02/26 18:10] (current)
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 +'''​Adult stem cells'''​ are multipotent,​ semi-differentiated,​ [[cell]]s that exist in all tissues. ​ "Adult stem cell", however, is not the preferred term used in the field to refer to them&#​8212;​developmental biologists will usually refer to them as "​tissue resident stem cells" or as a specific cell type (often referencing the genes they express). ​ They function to maintain tissue homeostasis by dividing to replace damaged or senescent somatic cells. ​ The two most well-studied examples of adult stem cells are the hematopoietic stem cells, which give rise to blood cells, and the intestinal crypt stem cells, which give rise to the intestinal epithelium.<​ref>​http://​</​ref>​
 +As multipotent cells, most adult stem cell types can generate cells of several different types. ​ However, because they are already epigenetically programmed to favor a particular fate, they generally cannot generate cell types outside of their lineage without genetic manipulation.
 +Identifying and characterizing stem cells within all adult tissues is an area of much intense ongoing research. ​ Understanding the mechanisms underlying the regulation of these stem cells has led to many recent breakthroughs in the field of cancer biology. ​ A recent paradigm-shift in cancer biology was the discovery that cancer is a disease resulting from dysregulation of adult stem cells. ​ The clinical implications of this concept are still being explored. ​ Obviously, there is still much in this field that remains unknown.
 +Functionally,​ adult stem cells are very different from embryonic stem cells. ​ Whereas embryonic stem cells are omnipotent, and may be coaxed with growth factors into producing any known cell type, adult stem cells are already partially committed to a particular fate and, without genetic manipulation,​ will only generate a limited number of cell types. ​ As stated above, this is currently an intensive area of research, but at the present the two are not practically equivalent.
 +[[Induced pluripotent stem cells]] are fully differentiated somatic cells that have been manipulated,​ either genetically or with growth factors (often a combination of the two), to become pluripotent stem cells. ​ These cells still retain some [[epigenetics|epigenetic]] imprinting of their original type--even with the most current techniques. ​ Mouse models have demonstrated that these cells have a significantly higher tumorigenic potential than transplanted embryonic stem cells. ​ As such, therapies involving induced pluripotent stem cells are primarily being studied only as options of last resort. ​ As scientists in the field devise better ways to generate these cells (new techniques are a current area of much research--there have been at least 40 published since 2009), they may become more clinically useful. ​ Until that happens, induced pluripotent cells cannot substitute for adult or embryonic stem cells in clinical medicine or research.
 +== References ==
adult_stem_cells.txt ยท Last modified: 2018/02/26 18:10 (external edit)