>From The Age,
http://theage.com.au/news/20000616/A10196-2000Jun15.html
-
Firm funds clone research for transplants
By PENELOPE DEBELLE
Friday 16 June 2000
A major United States medical company is funding Melbourne-based research
into the cloning and genetic manipulation of pigs to provide organs for
human transplantation.
The Australian Stock Exchange was advised yesterday about the deal by
Illinois-based company Baxter Healthcare to invest an undisclosed amount of
money into ongoing research by St Vincent's Hospital in Melbourne and an
Adelaide biotechnology company, BresaGen.
The aim of the research team is to clone a new pig from which the particular
gene believed to be responsible for organ rejection in humans has been
removed.
``At present, humans reject pig organs because of one particular bad gene,''
said BresaGen managing director John Smeaton. ``By eliminating this gene, we
are well on the way to eliminating one of the largest problems facing the
transplantation of pig organs into humans.''
Head of the research Tony d'Apice, of St Vincent's Hospital's Department of
Clinical Immunology, said the project sought to create a single pig from an
altered pig cell nucleus that could be bred normally and potentially farmed
for transplant organs.
``In vitro you can culture pig cells, any cells, and you can genetically
modify them - the problem is to turn that into a whole pig,'' Professor
d'Apice said.
The project, the only one of its kind in Australia, had been progressing for
some years at St Vincent's before the partnership with BresaGen was formed
and US funding sought.
Professor d'Apice said that at present no form of xenotransplantation -
transplanting living material between animals and humans - had occurred in
Australia, partly because ethical issues had not been ``thrashed out''.
The cloning process being developed in Adelaide is a technological
prerequisite to removing the offending gene and creating a new and altered
pig through cloning by nuclear transfer. ``What we are in the first instance
trying to do is to perfect the technology of cloning a pig,'' Professor
d'Apice said. ``Having perfected that, the next step is to then go on and
use genetically modified nuclei in the nuclear transfer experiment.''
The most likely organs to be considered for pig to human transplantation are
hearts and kidneys, and possibly pancreatic islet cells which have relevance
for diabetics.
Despite recent successes in Melbourne and Adelaide with the cloning of cows
and sheep, pig cloning has still to be developed in Australia. The only
group to succeed so far is the Edinburgh-based PPL Therapeutics, who cloned
Dolly, the sheep. ``Each individual animal species presents its own
challenges,'' Professor d'Apice said. ``The pig is especially difficult.''
Professor d'Apice said developments in xenotransplantation were subject to
continued assessment by bodies such as the National Health and Medical
Research Council and, in the US, the Food and Drug Administration and the
National Institutes of Health.
``This is happening in almost every major country in the world,'' Professor
d'Apice said. ``It is a matter of trying to determine the risks and the
benefits.''
The gravest potential risk to the future of pig to human organ transfers is
the presence in pig DNA of retroviruses known as PERVS - pig endogenous
retrovirus - which could infect humans.
``All the evidence at present is that they won't,'' Professor d'Apice said.
``On the other hand, the safeguards and issues that would be involved are
still the subject of discussion so that nobody today in this country has
gone ahead with any form of xenotransplantation.''
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