Stem Cell Basics
What are stem cells?
Stem cells are capable of dividing to produce more of themselves and to produce other specialized cell types that an organism needs to develop and live. In the adult, they can replenish cells that have died due to disease or injury. The process by which a cell changes from one type to another is called 'differentiation'. Cells that have acquired their final function are said to be ‘differentiated’. Initially, stem cells are said to be 'undifferentiated'.
Where are stem cells found?
In a mammalian embryo a few days old, a small group of cells called the ‘inner cell mass’ is formed. These master stem cells give rise to the main cell types of the body. Embryonic stem (ES) cells are produced from the inner cell mass in the laboratory. Throughout development different stem cells are formed that produce the specialized tissues and organs. The blood and skin contain stem cells that are constantly replenishing cells lost or dying. In other tissues, stem cells are much rarer. We are trying to identify and purify stem cells in various tissues.
What are the different types of stem cell?
Stem cells can be classified according to their source (embryonic, foetal, and adult), the tissue type (e.g blood, neural, skin) and what biologists call potency. Potency is how flexible a stem cell is at producing the differentiated cell types. Stem cells are said to be ‘pluripotent’ if they can produce many cell types. ES cells are the most pluripotent stem cells.
What are pluripotent stem cells?
Pluripotent stem cells differentiate to form many different cell types. In mice, ES cells grown in the laboratory can give rise entirely to a new offspring showing that they are fully pluripotent. Recently it has been shown that adult cells can be turned into cells that resemble ES cells. These cells are called induced pluripotent stem (iPS) cells.
Why do we want to use stem cells?
We study stem cells so that in the future we may be able to regenerate cells and tissues to treat degenerative diseases and injuries. Stem cells offer the possibility of developing more accurate methods to discover and test drugs. We can also use stem cells in the laboratory to study early human development which is otherwise inaccessible due to practical or ethical restrictions. The ability to create iPS cells opens up the possibility of creating cells directly from patients that suffer from a disease. Growing large numbers of these cells allows us to study the disease process in a dish.
Where can I find more information?
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