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Types of Human Stem Cells:
Embryonic, Umbilical Cord Blood & Adult Hematopoietic
from Science Prof Online
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When a stem cell divides, each new cell can either remain a stem cell or specialize into another type of cell, such as a muscle cell, skin cell, or red blood cell, to name just a few possibilities. These cells can theoretically divide without limit to replenish other damaged cells, and in doing so, can potentially act as a repair system for the body. Therefore, stem cell research is of great interest to the medical community.
Cord Blood Stem Cells
Umbilical cord blood is human blood obtained from the placenta and umbilical cord shortly after birth. Cord blood contains embryonic-like stem cells called CBEs. This type of stem cell is not quite as primitive as the controversial embryonic stem cells, which can give rise to any tissue type of the body. Still, CBEs are more versatile than adult stem cells such as those found in bone marrow.
In the late 1980s, these cells were used in the first successful sibling-donor transplant. Cord blood stem cells are now commonly stored in public and private cord blood banks, and have been used to treat a number of blood and immune-system related genetic diseases, cancers, and disorders.
More recent developments include a research project in 2005 in which a team of researchers at Kensington University successfully coaxed CBEs into differentiating into liver cells. CBE certainly hold promise for the future development of stem cell therapies.
Adult Stem Cells
An adult stem cell is an undifferentiated cell found in a tissue or organ. This cell type can produce more stem cells and can also give rise to specialized cell types of the tissue or organ they are located in. The main job of an adult stem cell is to maintain and repair the tissue in which it is found. When compared to embryonic and cord blood stem cell, adult stem cells are believed to be more limited in the type of cells that they can generate.
When the term 'adult stem cell' is used, bone marrow cells are typically the cell type being referred to; and adult blood forming (hematopoietic) stem cells from bone marrow have been used in transplants for the past 30 years.
However, researchers have found adult stem cells in many more tissues than they once thought possible. Certain kinds of adult stem cells, under the right conditions, appear to be able to differentiate into a number of different kinds of cells; a finding that has led some scientists to wonder whether adult stem cells can be used for a wider range of transplant types.
Sources
- Stem Cell Information page of the National Institutes of Health
This article originally appeared on Suite101 online magazine.
Article Summary: These special somatic cells are primitive, undeveloped research darlings that have the remarkable potential to differentiate into many different cell types.
Types of Human Stem Cells
Neurons derived from embryonic stem cells
Embryonic Stem Cells
As their name suggests, this type of stem cell is derived from embryos. Embryonic stem cells are obtained from donated embryos that have developed from eggs fertilized in vitro (in the lab), not from eggs fertilized in a woman's body.
Embryonic stem cells have a potentially unlimited capacity to replenish themselves and are pluripotent, meaning that they can differentiate into any cell type found in the adult body. Embryonic stem cell therapies have been proposed for regenerative medicine and tissue replacement after injury or disease.
Pluripotent, embryonic stem cells originate as inner mass cells within a blastocyst. The stem cells can become any tissue in the body, excluding a placenta. Only the morula's cells are totipotent, able to become all tissues and a placenta.
When a stem cell divides, each new cell can either remain a stem cell or specialize into another type of cell, such as a muscle cell, skin cell, or red blood cell, to name just a few possibilities. These cells can theoretically divide without limit to replenish other damaged cells, and in doing so, can potentially act as a repair system for the body. Therefore, stem cell research is of great interest to the medical community.
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