The Controversy Over Stem Cells
By Thomas F. Lee, Ph.D.
What's all the excitement (and controversy) in the media these
days about "stem cells"? And does this have anything to do with
arthritis? To answer the last question first: Yes! Arthritis
in its many forms is right there on the list of diseases for which
stem cells might offer a possibility for both repair of damaged
tissues or even, in some cases, a cure.
First, a quick review of the basics: Stem cells are the cells from
which "stem" all the tissues of the body - skin, muscle, cartilage,
blood, etc. After fertilization of the egg by a sperm, the tiny
human embryo, when it is still only a tiny ball of cells, contains
a cluster of "embryonic stem cells" from which develop the entire
human body. Some of those stem cells remain within the various tissues
throughout life, and remain as a reservoir of cells, now called
"adult stem cells," from which new tissue cells can be derived as
our tissues need repair and replenishment.
In addition to the stem cells in the early embryo and fetus, there
are relatively high numbers of stem cells (but still only a very
few) in bone marrow and in umbilical cord blood, while others reside
in smaller numbers in many other adult tissues - including the blood
and nervous system. These stem cells can be harvested in various
ways and grown in the laboratory as stem cells, or - and here is
the reason for all the excitement - they can be triggered to develop
into specialized tissues such as bone, cartilage, and muscle.
So the potential exists to use stem cells to repair defective damaged
tissues in disorders such as Parkinson's, spinal cord injury, diabetes,
osteoarthritis and rheumatoid arthritis (RA), to name just a few.
The "trick" is to figure out the precise conditions that will stimulate
the stem cells to make these repairs. I have to emphasize that a
lot of complicated scientific research will be needed before that
promise becomes a practical and safe reality. Worldwide efforts
are now underway to do just that.
There have already been a number of intriguing trials using the
stem cells from bone marrow to try to wipe out severe RA. The risky,
complicated procedure involves removing a sample of a person's bone
marrow, getting rid of the remaining marrow by drugs and irradiation,
and putting back into the subject the marrow sample cleared of almost
all other cells except the stem cells. This might, in effect, "reboot"
the person's marrow, making a fresh new immune system, leaving RA
as only a bad memory. Researchers in Australia, Belgium, Canada,
Chicago, and the Netherlands have done just that, and many of their
subjects are still in remission. Future human trials will undoubtedly
use stem cells to try to replace damaged joint tissues by injections
of stem cells, perhaps genetically altered, or even by stimulating
resident stem cells to make their own repairs.
Why is there so much controversy surrounding stem cells? It has
to do with the fact that many scientists want to extract stem cells
from human embryos, thereby killing the embryo. In one sense the
problem is simple. If one regards the embryo as a human individual,
and its destruction as a kind of murder, then of course extracting
embryonic stem cells is morally unacceptable. If one does not regard
the embryo as having such a protected status, the use of these cells
is not a problem. Since this dilemma involves humans with differing
ethical standards, as well as politics, business interests, and
health issues, this is sure to be a hot topic for a long time to
come.
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About the Author
Dr. Lee has rheumatoid arthritis and has written on stem cells
for the Encyclopedia Americana. His latest book is Conquering
Rheumatoid Arthritis: The Latest Breakthroughs and Treatments.
Thomas F. Lee, Ph.D.
Prometheus Books 2001
ISBN: 1-573-92886-0
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this book at barnesandnoble.com |
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