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[IP] Organ transplants from pigs possible in 5 years

(Here's that FIVE years thing, again. <s>) I thought this might be of
interested to a few here:


Organ transplants from pigs possible in 5 years 02/18/2002

The Associated Press

BOSTON - Transplanting genetically modified hearts and other organs from
pigs to people could be possible in five to seven years, but many scientific
and ethical questions remain, scientists said Sunday.

Researchers are changing pigs' genes to "humanize" their organs, making them
more like people's so they will serve as alternatives to human cadavers for
transplanted organs.

The scientists described the progress toward animal sources -- an approach
called xenotransplantation -- at a conference in Boston sponsored by the
American Association for the Advancement of Science.

Sunday's meeting followed an important milestone last month. Two companies
said they have produced litters of cloned miniature pigs that lack one copy
of a gene that makes pig parts incompatible with human immune defenses.

"I strongly believe it will be a major step forward, but it won't be the
only problem to be solved," said Dr. David Cooper of Massachusetts General

Both Cooper and Dr. Fritz H. Bach, another transplant scientist at Boston's
Beth Israel Deaconess Medical Center, predicted that the transplants could
take place in the next five to seven years, if these problems can be figured

In January, Immerge BioTherapeutics and PPL Therapeutics both said they had
created pigs that lack one of the two usual copies of a gene that makes a
sugar called alpha-1-galactose.

This sugar lines pig blood vessels. Because it is nearly identical to a
bacterial sugar, the human immune system attacks it. As a result, pig organs
transplanted into people are destroyed almost instantly.

Immerge's pigs were born in September and October and PPL's in December. The
next step will be to breed these pigs with each other. Cooper said efforts
to do this should begin within two months as the oldest animals reach sexual

There is a 1-in-4 chance that each offspring will be born with no copies of
the gene. No one knows for sure whether pigs can survive without
alpha-1-galactose. But if they can, the animals could be raised to supply
hearts and kidneys for human transplants.

Scientists will have to test the process first by transplanting the pig
organs into other animals, such as baboons. Another worry is whether the
organs will carry pig viruses that could be harmful to people, especially if
they spread from the organ recipient to others.

Bach said people should debate whether the risk, however remote, is worth

"We live in a world of risk, and this is an additional risk," said Bach. "If
the medical establishment imposes this on the public and there is a
potential risk, I feel ethically we have to go to the public." However,
Cooper said the decision should be left to regulatory agencies, which have
the expertise to wade through the highly technical arguments on both sides.

All pig cells carry a so-called retrovirus that is harmless to them, but no
one knows what it might do to humans. Scientists are working with a strain
of pigs that cannot spread this virus to human cells. However, Bach said he
is concerned about possible pig viruses that have not been discovered yet.

Cooper responded that scientists can only guard against viruses and other
hazards that have been identified. "You deal with all the known problems,
but if you worry about unknown problems you will never make any success in
any branch of science." According to the United Network for Organ Sharing,
about 77,000 Americans are in line for transplants each year, while 23,000
actually receive them. Demand is growing five times faster than the supply,
and many who could benefit never even make the waiting list, because they
have other health problems.
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