| |
 |
|
| Medical Edge |
|
|
|
Medical Edge Newspaper Column from Mayo Clinic
ANIMAL-ORGAN TRANSPLANTS MAY ONE DAY BE FEASIBLE
DEAR MAYO CLINIC: I just proofread a paper my daughter wrote for
high school, in which she cited a newspaper story that said scientists
one day hope to transplant pig hearts into people. Is this true? It sounds
like something from the tabloids to me, and I don’t want her getting up
in front of class making a fool of herself. If this is accurate, why is
this necessary? — Buffalo, N.Y.
ANSWER: The newspaper story your daughter cited concerns “xenotransplantation”
— the transplantation of cells, tissues or organs from one species into
another.
Although xenotransplantation sounds fantastic and far into the future,
it has been at the center of research in the field of transplantation
for many years and has been carried out in people.
In the early 20th century, when experimental surgeons first developed
techniques that would enable them to perform transplants, they tried to
determine the best source of organs to transplant into people with organ
failure. At that time, it was not clear how to obtain human organs for
transplantation, and so they used animals’ organs.
In fact, the first organ transplants in people were performed using pig
and sheep kidney “xenografts.” These xenografts, like others attempted
since then, did not function for very long. Surgeons then discovered how
to transplant human organs successfully.
Today, transplantation of human organs is often the preferred treatment
for severe failure of the heart, kidneys, liver or lungs. However, the
number of human organs available for transplantation is far fewer than
the number needed. In fact, because human organs are so scarce, we estimate
that 10 to 100 people in the United States die every day while waiting
for an appropriate donor — and this number is growing.
For this reason, physicians, surgeons and scientists having been studying
the possibility of using animals as a source of organs for transplantation.
What prevents us from using animal organs in people is not the function
of the organs — in many cases, research has shown that animal organs would
function almost as well as human organs. Rather, it is the immune reaction
of the human recipient against the animal tissue that stands in the way.
To prevent this reaction, recipients of human organ transplants take immunosuppressive
drugs. However, these drugs do not completely prevent the destruction
of xenografts. To make it possible to transplant organs from animals into
people, scientists have focused on genetically engineering animals to
decrease the intensity of the immune reaction.
Currently, xenotransplant technology is still in the experimental stage.
Animal organs are not being transplanted into people. However, some animal
cells — which are less subject to destruction by the immune system — have
been transplanted into people experimentally over the past 10 years, and
more are expected.
I can see how reading about this concept might surprise or even unsettle
people who aren’t involved in the care of patients with organ failure.
Our attempts to use animal cells today, and the hope of using animal organs
in the future, reflects an agonizing situation in which we actually have
a treatment that we know works — organ transplantation — but we cannot
apply it because we lack replacement organs.
Xenotransplantion is just one area of a larger field called regenerative
biology. In the future, tissue engineering, immune-system modifications
and organ regeneration may revolutionize the care of patients with organ
failure.
The need for regenerative biology and organ transplantation will not diminish
over time. There looms a greater crisis: New research will enable physicians
to diagnose diseases such as cancer years before they cause symptoms.
Then, of course, physicians will be tempted to try to replace the affected
organ. This will greatly exacerbate the organ shortage.
By carefully researching various regenerative biology techniques today,
we will be in a better position to serve the public health in the future.
Jeffrey Platt, M.D., Transplantation Biology, Mayo Clinic, Rochester,
Minn.
Additional Resources:
Transplant Center
Appointment
Information
More
Information on Organ Transplants
- - -
Medical Edge from Mayo Clinic is an educational resource and doesn’t
replace regular medical care. To e-mail a question, go to www.mayoclinic.org,
or write: Medical Edge from Mayo Clinic, c/o TMS, 2225 Kenmore Ave., Suite
114, Buffalo, N.Y., 14207. For health information, visit www.mayoclinic.com.
© 2004 TRIBUNE MEDIA SERVICES, INC.
|
|
