 A stem cell
is a cell that has two abilities: to divide and make identical copies of
itself, and to give rise to any of the body’s different cell types, including
heart, muscle, skin and nerve cells. Human bodies have 210 different cell
types.
Where do stem cells come
from?
Human stem cells come from four
different sources and in four varieties.
1. Embryonic stem cells are taken from a human
embryo when it is about five days old. At this stage of development the embryo
is a collection of 50 to 100 cells, smaller than a grain of sand, called a
blastocyst.1
Human embryonic stem cells are
thought to have much greater  Developmental potential than Adult stem cells.
This means that embryonic stem cells may be pluripotent — that is, able to give
rise to cells found in all tissues of the embryo except for germ cells rather
than being merely multipotent — restricted to specific subpopulations of cell
types, as adult stem cells are thought to be.2
2. Adult stem cells are harvested from many
different tissues in the body — including bone marrow, blood and skin — of a
fully developed human being without harming the person.
3. Foetal stem cells are taken from the foetal
remains after a termination of pregnancy.
4. Umbilical stem cells are drawn from the
residual blood left in the umbilical cord of a newborn baby. These are in fact
adult stem cells.2
How can stem cells be used in therapy?
Medical researchers believe that
stem cell therapy has the potential to radically change the treatment of human
disease. A number of adult stem cell therapies already exist, particularly bone
marrow transplants that are used to treat leukaemia.
Stem cells have potential in many different
areas of health and medical research. To start with, studying stem cells will
help us to understand how they transform into the dazzling array of specialized
cells that make us what we are. Some of the most serious medical conditions,
such as cancer and birth defects, are due to problems that occur somewhere in
this process. A better understanding of normal cell development will allow us
to understand and perhaps correct the errors that cause these medical
conditions.
The use of stem cells to repair or
replace damaged brain tissue is a new and exciting avenue of research. A neural
stem cell is a special kind of cell that can multiply and give rise to
other more specialized cell types. These cells are found in adult neural tissue
and normally develop into several different cell types found within the central
Nervous system. At the moment, stem cell research for TBI is in its infancy,
but future research may lead to advances for treatment and rehabilitation.3
At this stage in time, however there
are no stem cell treatments available for brain injury anywhere in the world.
Stem cell scientists have issued a warning to patients about the potentially
grave risks of travelling internationally in search of untested stem cell treatments.
Beware of international conmen promising safe effective stem cell treatment
unavailable in the west, they are not to be trusted.4
Further information
- Wikipedia: http://en.wikipedia.org/wiki/Stem_cells
- National Institute of Health, USA: http://stemcells.nih.gov
- National Institute of Neurological
Disorders and Stroke,
USA: http://tinyurl.com/38a2rv
- ABC News: Warning against stem-cell research: http://tinyurl.com/3dggp8
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Stem Cells