Stem Cells
Adult Stem Cells or Tissue-specific Stem Cells - The term ‘adult stem cells’ is often
used very broadly and may include fetal and cord blood stem cells.
Many adult tissues contain stem cells that may:
- Replace cells that die.
- Restore tissue after injury.
Adult stem cells are tissue-specific, meaning they are found in a given tissue in
your body and generate the mature cell types within that particular tissue or organ
for example they are found in the:
- Skin,
- Muscle.
- Intestine.
- Bone marrow - In the bone marrow, billions of new blood cells are made every day
from blood-forming stem cells
Each contain their own stem cells.
It is not clear whether all organs contain stem cells?
There are a few stem cell therapies which use tissue-specific stem cells. They are:
- Bone marrow or cord blood stem cell transplantation to treat diseases and conditions
of the blood or to restore the blood system after treatment for specific cancers.
- Skin stem cell therapies for burns.
- Limbal stem cells for corneal replacement. In each case, the stem cells repair the
same tissue from which they came.
The mesenchymal stem cell (MSC) is another type of adult stem cell found in a number
of tissues which may be able to produce:
- Bone cells - osteoblasts
- Cartilage cells - chondrocytes.
- Fat cells - adipocytes.
These or similar cells may aid in the regeneration of tissues.
Cord Blood Stem Cells - Cord blood is obtained from the umbilical cord at the time
of childbirth, after the cord has been detached from the newborn. [1] The blood in
the umbilical cord is rich in blood-forming stem cells. The applications of cord
blood are similar to those of adult bone marrow and are currently used to treat diseases
and conditions of the blood or to restore the blood system after treatment for specific
cancers. Cord blood stem cells are tissue-specific.
Embryonic Stem Cells - are derived from very early embryos and may in theory give
rise to all cell types in your body. But coaxing these cells to become a particular
cell type in the laboratory is not trivial. Furthermore, embryonic stem cells carry
the risk of transforming into cancerous tissue after transplantation. To be used
in cell transplant treatments the cells will most likely need to be directed into
a more mature cell type, both to be therapeutically effective and to minimize risk
that cancers develop. There are currently no treatments using embryonic stem cells
accepted by the medical community.
Fetal Stem Cells - are taken from the foetus. Most tissues in a foetus contain stem
cells that drive the rapid growth and development of the organs. Like adult stem
cells, fetal stem cells are generally tissue-specific, and generate the mature cell
types within the particular tissue or organ in which they are found.
Induced Pluripotent Stem Cells (iPS cells)
In 2006, scientists discovered how to “reprogram” cells with a specialized function
(for example, skin cells) in the laboratory, so that they behave like an embryonic
stem cell. These cells, called induced pluripotent cells or iPS cells, are created
by inducing the specialized cells to express genes that are normally made in embryonic
stem cells and that control how the cell functions.
Embryonic stem cells and iPS cells share many characteristics, including the ability
become the cells of all organs and tissues, but they are not identical and can sometimes
behave slightly differently. IPS cells are a powerful method for creating patient-
and disease-specific cell lines for research. However, the techniques used to make
them need to be carefully refined before they can be used to generate iPS cells suitable
for safe and effective therapies.
1. Cord Blood Banking - Buzz.com - website
The developing baby is referred to as a foetus from approximately 10 weeks of gestation
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