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Stem cells
I think you have heard the phrases called an "iPS cells" and "ES cells" at least 1 time .
Incidentally, do you know what "ES" and "iPS" mean?
The official name of "ES cells" is "Embryonic stem cells", and the official name of "iPS cells" is "Induced pluripotent stem cells".
Both "Embryonic stem cells", and "Induced pluripotent stem cells" include the phrase "Stem cells". We will explain "Stem cells" from now on.
Cell structure of the animal body
There are two kinds of creature. One is "Monadic" like an amoeba, a paramecium and so on. Another is "Multicellular organisms" like humans.
As we explained on the former page, we form our bodies through repeating division, differentiation, and growth.
However, division, differentiation, and growth were not performed by one cell.
There are three kinds of cells which constitutes a multicellular organism. They are them named "Differentiation cells", and "Transient amplifying cells", "Stem cells".
As the name suggests, the cells which are continuously
differentiating and changing to various different cells are differentiation cells.
In fact, most differentiation cells don't multiply. Therefore a body is maintained by transient amplifying cells multiplying instead.
The number of divisions has a limit in transient amplifying cells, and they do not have an utonomous replication ability. So, in order to maintain the body, the cells which produce Transient amplifying cells are needed. Then, it is the turn of a Stem cell.
Stem cells
Generally speaking, the cells which have differentiation ability and self-replication competence are Stem cells.
The number of divisions of differentiation cells and transient amplifying cells have a limit, but Stem cells can multiply semipermanently.
The bodies of multicellular organisms are maintained by three cell's supporting each other.
Stem cells are used for the treatment of diseases and injuries as a part of regenerative medicine.
Application to regenerative medicine
Generally, the stem cells which exist in an adult organism's body divide slowly.
That's why research which takes out stem cells from the body, and research to take this out outside a body and multiply it efficiently is performed extensively.
The somatic stem cells which are obtain from the patient's own organ have few on risks of ethical problems and rejection.
So, it is cosidered as an important cell source in the cell transplant medical care.
※It is said that bone marrow transplantation for a donor and a genotypical near patient is a kind of somatic stem cell transplant which is already put to practical use.
When we apply cell medical care to a patient with a genetic disease, we can take a cell from the patient instead of using a cell derived from a cell bank gene therapy is needed in order to cure a hereditary disease completely.
Therefore in gene therapy, a cell with high proliferation potency is needed.
However, as I said some time ago. We can't multiply the somatic stem cell of adult origin outside of the body well.
On the other hand. embryonic stem cells and induced pluripotent stem cells attract attention as a cell source in the future of cell transplant medical care, because compared with a somatic stem cell, those cells have the differentiation capacity to more nearly various organs.
Moreover we can multiply those cells abundantly outside of the body.
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