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Stem Cell Information and Definitions
Differentiation
Differentiation is the process whereby an unspecialized cell acquires the
features of a specialized cell such as a neuron, heart, liver, or muscle
cell. There are more than 250 general types of cells in the human body.
Stem Cells
Stem cells are the body’s blank or “master” cells. They are the foundation
cells for every organ, tissue, and cell in the body. Stem cells can renew
themselves indefinitely and give rise to (differentiate) many types of
specialized cells, such as muscles, nerves, organs, bone, blood, and so on.
These properties make stem cells different from the body’s other mature
cells. For example, a skin cell can only divide and generate new skin cells.
The ability of stem cells to become other types of makes them essential for repairing and renewing body tissues throughout our lives. Unfortunately, our stem cell reserves are finite. As they become depleted, we succumb to diseases, disorders and the ravages of aging. Thus, stem cell therapy offers the potential to replenish our reserves and fight a wide variety of diseases and disorders.
Adult Stem
Cells
These cells can renew themselves and differentiate into some cell types
other than the tissue originally containing the cells. Adult stem cells are
undifferentiated cells found in a many tissues, including brain tissue. The
most common place to find these cells is in bone marrow. The marrow is taken
from the back of the donor’s upper hip bone.These cells can give rise to
some completely different tissues, such as nerve cells in the brain, liver
cells, and heart muscle cells.
The bloodstream also carries adult stem cells, but their concentration is lower than in bone marrow, thereby making harvesting a tedious process.However, recent technology has made this somewhat slow harvesting process more efficient and now this technique is much more common.
Adult stem cells can also be found cord blood. However, cord blood has a fixed amount of stem cells which may not be enough for a patient and a second donation may not be available. There is also a chance that a genetic disorder might be transmitted through cord blood.
Embryonic Stem Cells
When a sperm fertilizes an egg, it becomes what is known as a zygote.
Zygotes have unlimited potential, or plasticity, as far as growth and
differentiation and they have the ability to develop into any type of cell.
Because the zygote has the highest degree of plasticity, it is referred to
as a totipotent stem cell.
After fertilization, the zygote begins to divide, and eventually forms a blastocyst. Blastocyst stem cells have less plasticity and are more specialized than totipotent zygote stem cells: Those on the outer surface of the blastocyst develop into the placenta and other tissues that surround the fetus, while those inside, referred to as embryonic stem cells, become the cells of all the fetal organs and tissues. These stem cells can become any of the more than 200 types of cells in the body and they are called pluripotent stem cells.
Embryonic stem cells are obtained from embryos that develop from eggs that have been fertilized in an invitro clinic and then donated for research purposes with informed consent of the donors.
Neural Stem Cells
Neural stem cells are found in adult neural tissue. They have the ability to
differentiate to form three types of functional cells of the nervous system,
which are astrocytes, oligodendrocytes, and neurons.
Multipotent Adult Progenitor Cell (MAPC)
The Multipotent Adult Progenitor Cell (MAPC) is a stem cell found in human
bone marrow, which can be meticulously cultured to have the ability to
differentiate into every kind of adult body tissue.
Pluripotent Stem Cells
Pluripotent stem cells have the ability to develop into many, but not all,
different types of cells found in the human body. Examples of pluripotent
stem cells include the embryonic blastocyte and stem cells found in adult
bone marrow.
For more information on Stem Cell Research, please
email:
MCGNEUROLOGYSTEMCELLS@mail.mcg.edu