- LONDON (ANI) -- The cloning
of a special little pig has been done.
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- Since new sources of organs are desperately needed to
treat the thousands of critically ill people on the transplant waiting
list, this achievement stands for a major milestone in the effort to breed
animals with organs that can be transplanted into human patients.
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- The announcement that scientists have cloned a miniature
swine with both copies of a specific gene "knocked out" of its
DNA to help curb rejection was made at the annual meeting of the International
Embryo Transfer Society in Auckland, New Zealand, according to a report
in news.telegraph.com.
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- The ultimate goal of research by Prof Randall Prather
of the University of Missouri-Columbia, in partnership with the company
Immerge BioTherapeutics, is to develop a herd of miniature pigs that can
be used as a safe source for human transplantation, known as xenotransplantation.
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- Last year PPL Therapeutics announced that it had produced
"double knock-out" pigs but its rivals at Immerge believe its
smaller swine are better suited to transplants.
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- Prof. Prather said: "The fact that we have been
able to clone this particular strain of miniature swine with both copies
of the gene that produces GGTA1 knocked out is a very exciting step for
the field of xenotransplantation."
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- "Organs from regular swine are too large for human
transplant, and this particular strain of miniature swine has been refined
for years solely for its potential use in humans."
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- Researchers have targeted the pig as the best potential
candidate for an alternative organ source because of the similarity between
human and pig organs and the relative ease of breeding. However, the massive
rejection response mounted by the human immune system has been a major
hurdle.
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- Aside from rejection, the biggest obstacle comes from
porcine endogenous retroviruses, or PERVS, which are part of the pig's
genetic code. They are harmless to pigs, and not easy to spread, but critics
argue that no one knows what will happen once they are introduced to humans
in transplanted organs.
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- In the case of the miniature pigs, though they have PERVs
that can infect pigs, "the strain of swine we are working with seems
to be incapable of transmitting PERVs to human cells in culture,"
said Dr Julia Greenstein, President of Immerge.
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- Clinical studies of the double knock-out pig tissue in
primates are now planned. However, patients may still have to wait many
years before humanised pigs can help overcome the desperate shortage of
transplant organs. (ANI)
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