Answer:
Stem cells are unspecialized cells that have not yet “decided” what type of adult cell they will be.
They can self-renew and make two new stem cell
They can differentiate to make multiple types of cells
They ultimately amplify by expanding the number of differentiated & mature cells
There are several different types of stem cells produced and maintained in our system throughout life. Depending on the circumstances and life cycle stages, these cells have different properties and functions. There are even stem cells that have been created in the laboratory that can help us learn more about how stem cells differentiate and function. A few key things to remember about stem cells before we venture into more detail:
Stem Cells are NOT new to science
The definition is relatively simple (see above)
Stem Cells are not all the same. There are different types of stem cells:
Adult Stem Cells (ASC)
Embryonic Stem Cells (ESC)
Induced Pluripotent Stem Cells (iPS)
Stem Cells are important in tissue homeostasis (maintenance), repair and regeneration
Some Stem Cells (adult) are clinically useful NOW
Other Stem Cells (ESC, iPS) MAY be clinically useful someday – already useful in basic research
All Stem Cell types are important in research
There are both ethical and political issues with the use of some types of stem cells. UNMC continues to work closely with federal and state legislature as well as the International Society for Stem Cell Research (ISSCR) to promote responsible, transparent, and uniform practices that conform to both federal and state guidelines.
Stem cells are the foundation cells for every organ and tissue in our bodies. The highly specialized cells that make up these tissues originally came from an initial pool of stem cells formed shortly after fertilization. Throughout our lives, we continue to rely on stem cells to replace injured tissues and cells that are lost every day, such as those in our skin, hair, blood and the lining of our gut.
Source ISSCR
Stem Cell History
Until recently, scientists primarily worked with two kinds of stem cells from animals and humans: embryonic stem cells and non-embryonic "somatic" or "adult" stem cells. Scientists discovered ways to derive embryonic stem cells from early mouse embryos nearly 30 years ago, in 1981. The detailed study of the biology of mouse stem cells led to the discovery, in 1998, of a method to derive stem cells from human embryos and grow the cells in the laboratory. These cells are called human embryonic stem cells. The embryos used in these studies were created for reproductive purposes through in vitro fertilization procedures. When they were no longer needed for that purpose, they were donated for research with the informed consent of the donor. In 2006, researchers made another breakthrough by identifying conditions that would allow some specialized adult cells to be "reprogrammed" genetically to assume a stem cell-like state. This new type of stem cell is now known as induced pluripotent stem cells (iPSCs).
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