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by Mary Kowalski
Imagine that in the future, an individual who develops diabetes, or
suffers serious burns, or develops schizophrenia or Alzheimer disease,
could be cured. The prospective cure would involve having access to his
or her own cells that have been maintained since birth. The cells that
offer such great medical potential are called stem cells.
What exactly is a stem cell? It is a type of general purpose cell that
everyone has. It can regenerate itself over long periods of time. If the
stem cell receives a message to change, it can develop into specific
cells which become part of specific tissues.
The medical scientists of the not-so-distant future may be able to
manipulate an individual’s stem cells as a routine part of medical
therapies. Today’s medical treatments involve treating symptoms and
prescribing medications, often for lifetime use. The future physician
may be able to prescribe stem cell therapy which will cure, thus
eliminate, the medical problem.
The typical newborn infant, who now has his footprints taken and saved,
could also have some of his or her cells taken and saved. These cells
would be nurtured in special laboratories in small cultures for the
future of that individual. When needed, the stem cells would be treated
with the appropriate chemicals to create the needed tissue.
The most amazing thing about a stem cell is its ability to change into
so many different types of cells and tissues. The scientific world knows
that a stem cell is unspecialized. That is to say, stem cells are basic
cells which have a lot of potential but need further training.
Under certain physiologic or experimental conditions, stem cells can be
changed into specific cells. The basic stem cell can become skin tissue,
heart muscle, brain tissue, blood tissue, kidney tissue, and many other
types of tissue cells.
Currently, repair of damaged tissue is limited. Many tissues of our
bodies a have a few cells that can repair tissues. Some body cells, such
as in the brain and spinal cord, do not regenerate. Thus, damaged nerves
of a spinal cord become useless and the individual can be paralyzed.
Rather than trying to fix a damaged area of the body using its existing,
limited resources, a stem cell creates new cells. Stem cell therapy
could change everything about the medical therapies that we currently
use.
Several categories of stem cells exist. The most powerful and versatile
stem cells are called totipotent and come from an embryo. The embryo is
one example of a cell that has the potential of becoming millions of
other types of cells. Totipotent stem cells can become any type of cell
and tissue in the body. Currently research is limited by law to
pre-existing cultures of embryonic stem cells.
Adult stem cells have a variety of names with a variety of abilities.
The natural forces of the adult body already can change many
general-purpose stem cells into specific tissue cells. However, adult
lines, or cultures, of stem cells do not have the creative capabilities
of the younger versions of embryonic stem cells. Research is quite
actively trying to make the adult stem cell lines more flexible.
Some types of stem cells have been highly successfully used for 40
years. The blood- forming stem cells, called hematopoietic stem cells,
have been used to treat leukemias, lymphoma, and many types of blood
disorders.
Perhaps, in a future scenario, a person, who can no longer produce
adequate insulin and becomes a diabetic, would be able to access his own
stem cell line that has been saved from birth. The cells would be
treated, or told, to become insulin-producing cells of the pancreas. The
patient would be given the specialized cells and the diabetes would be
cured.
The same line of stem cells that was used to create a pancreatic cell
could also be induced to become skin cells after burns or heart muscle
to repair heart damage. Repair of genetic defects and the growth of new
nerves for the spine would be possible.
Future patients, who need organ replacement, would not need to be on
long waiting lists. Their own cells could create the necessary tissues.
And, they would not have any problems with rejection of the new organ as
foreign tissue, because the stem cells that created the new tissues and
organ, originally belonged to that individual.
The potential healthcare effect of stem cell use is beyond our current
imaginations. The quality of life would be greatly affected. It would be
possible to save huge amounts of healthcare dollars that are now used on
maintenance, e.g., hospitalizations, prescription drugs, or dialysis.
Instead, an individual could be treated and cured, and all because a few
cells were saved at birth.
For more information on stem cells and stem cell research, visit the
websites of the National Institutes of Health at
www.nih.gov.
February 2003
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