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 SPECIAL FARM SUPPORTS
RESEARCH
BY BOB REEVES -- Lincoln Journal Star
The hog confinement unit in northeast Nebraska looks
like many others around the state.
So do the pigs.
But the pigs raised here are not destined for the dinner
table, and the farmer who owns the place has doctoral degrees in veterinary
science and nutrition.
In 1999, the farm produced 30 to 35 pigs for use in
Dr. William Beschorner's xenotransplant research at the University of
Nebraska Medical Center. The project, which centered on transplanting
hearts from pigs to sheep, was a small step toward the distant dream of
transplanting animal organs to humans.
The pig farmer/veterinarian refused to be identified
by name or location to avoid conflicts with opponents of animal research.
For the past 12 years, he said, he's been producing
"specialty-use, highly clean pigs."
"We were particularly excited to work with UNMC on
this procedure where there's a link between our animals and a potential
for saving human lives," he said.
Most of the pigs he has raised have been used to test
veterinary drugs and antibiotics.
His operation is similar to specific-pathogen-free
farms, which produce pigs that are guaranteed free from a list of six
pathogens that infect hogs in Nebraska. But this hog producer holds his
pigs to a higher standard. His buildings are equipped with an air filter
that removes the smallest particles, including all bacteria and viruses.
"If we were producing pigs for human organ transplants,"
he said, "we envision an environment where the caretakers are fully masked
(to prevent exposing pigs to human disease germs)."
In his contract with Beschorner's research company,
named Ximerex, the farmer used his veterinary expertise to precisely time
the gestation of sows and deliver them to the Medical Center at a specified
point in the fetal pigs' development. Doctors in Beschorner's lab anesthetized
the sows and, using ultrasound imaging, injected sheep bone marrow, into
several fetuses.
When the sows' 112-day gestation was up, the veterinarian
delivered the baby pigs by Caesarean section to avoid contamination. The
pigs, known as chimeric pigs, were raised in the ultra-clean environment
for several weeks until they were the proper age for organs to be harvested.
Blood samples then were taken to identify the chimeric
pigs - those with genetic material from a sheep. Researchers selected
the pig that best matched the sheep, anesthetized it and removed its heart
for use as a transplant.
Pigs are good choices for xenotransplants because of
their short gestation period and rapid growth rate, the farmer said. If
the procedure were to be used with humans, a patient needing an organ
would supply bone marrow to be injected into a fetal pig, then receive
the transplant from the pig in less time than most people wait for human
organs today, he said.
However, he added, the day when xenotransplants will
be available for humans is years - even decades - in the future.
If hogs are raised in a pathogen-free environment,
and carefully screened for all known diseases, the chances of passing
a disease to a human host are slim, the farmer said. Although it's theoretically
possible a pig virus could mutate inside a human, the odds against it
causing an epidemic are "astronomical," he said.
Farmers who work with pigs daily or handle raw pork
in packing plants would be in more danger of a mutation than someone who
receives an organ from a specially screened pig, he said.
"That's been going on for years and years, and we've
never had an epidemic."
Although the need for organs is great, the profits
to pig farmers would be minuscule, even if 100,000 or more pigs were used
each year for transplants, he said.
"From the perspective of agriculture, that's one morning's
slaughter," the farmer said, then added jokingly, "I don't think it will
have a noteworthy impact (on agriculture) but it would raise the image
of pigs in the world."
Reach Bob Reeves at breeves@journalstar.com
or 473-7212.
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