the name sounds sci-fi. Xenotransplantation is the process of taking
organs from donor animals, and transplanting them to humans. It
hasn't been successful in the past, but genetic engineering just
might make it work.
isn't a new one. Some of the first known operations were actually
performed all the way back in 1906. French surgeon Mathieu Jaboulay
implanted a pig's kidney into one woman, and a goat's liver into
another. Both patients died.
to a world famous case. In 1984 a team of surgeons implanted a baboon
heart into an infant in desperate need of a new heart. "Baby
Fae" died after 20 days but the idea didn't.
Why is the
idea still being pursued? The alarming shortage of donor organs.
Many people suffer for years, or even die, while waiting for a suitable
donor organ. In order to increase the supply of organs available,
science is trying to produce animal organs that won't be rejected
by human bodies.
one of transplantation's biggest hurdles. Whether the donor organ
comes from a person or an animal, the recipient's immune system
is likely to reject it. To overcome that hurdle, genetic engineering
can adjust the genetic makeup of donor animals, adding or subtracting
specific genes, to make the organs compatible to humans.
In 2002 PPL
Therapeutics, the company that created Dolly the cloned sheep, announced
new "knock-out" pigs. These cloned piglets had specific
genes "knocked-out" - removed from their DNA. The genes
produce a substance that guarantees rejection. Without the genes,
the substance is gone, increasing the odds that the organ is accepted.
xenotransplantation charge that not nearly enough is known about
the process. Viruses that are normally carried only by animals could
cross the species boundaries causing problems for people. There
are also serious ethical objections to the process. Should animals
be bred as organ factories for humans?
Is genetic engineering the only answer to the organ shortage? Is
it ethical to change the genetic makeup of animals to take their
D. Food and Drug Administration. "Organ Transplants from Animals:
Examining the Possibilities." (Online.) http://www.fda.gov/fdac/features/596_xeno.html September 2002.
Transplant Hopes Rise." (Online.) http://www.cnn.com/2002/TECH/science/01/02/genetics.pigs/index.html September 2002.
Mark. News.Com.Au. " Pig-organ Transplants Closer." http://www.news.com.au/common/printpage/0,6093,4960482,00.html September 2002.