Although it appears that primates will never be used as sources for human
transplants, they are being used in xeno research, primarily as recipients for
pig organs. In the UK such experiments are permitted where the researchers can
demonstrate that there is no alternative. The reasoning is that while using an
ape or monkey as an organ source could potentially benefit just one, or at most
a handful of humans, the amount of knowledge that could be gained from research
on just one animal could potentially help many people.
Given the closeness of man to non-human primates, apes are used very sparingly,
though experiments are regularly conducted on monkeys. In 1999 the Home Office,
the department which licenses animal experiments in the UK, revealed that 270
monkeys had been killed in xenotransplantation research in the last four years.
In 1999 three baboons were used in xeno research and seventy-nine cynomolgus
monkeys. Primates are therefore used - though in limited numbers - in both the
UK and the US. In particular, pigs' hearts are grafted onto baboons to test and
monitor the efficiency of the anti-rejection measures undertaken by the
By any standards, these experiments are some of the most grisly procedures
carried out anywhere in the name of science. They do sometimes involve a full
transplant of a genetically modified pig heart into a monkey. In some cases,
however, the doctors will graft the transgenic hearts onto a baboon's neck
arteries, as this allows them to observe the way the pig heart behaves in
another species, and monitor the rejection process. The operation is carried
out under general anaesthetic and the baboon is humanely killed afterwards.
These measures, however, do not pacify animal rights campaigners, who say the
experiments are cruel and unnecessary.
Some of the fiercest criticism of animal experiments comes in Britain, where
the animal rights debate has a long history - the world's first
anti-vivisection organisation was founded in London in 1875. At the heart of
the animal rights movement today is the British Union for the Abolition of
Vivisection (BUAV). Founded in 1898, the organisation campaigns against any use
of animals in medical experiments. Their general case against animal
experiments is that it is morally unjustifiable. 'To inflict suffering on
defenceless animals during experiments is wrong. We do not have the right to
experiment on or use animals for our benefit,' they say.
However, they have additional specific arguments against xenotransplantation.
They point to the immunological, physiological and biochemical differences
between pigs and humans as challenges yet to be overcome.
Dr. Gill Langley is not what some would regard as a typical animal rights
campaigner and her opposition to animal experiments is based on far more than
an emotional attachment to furry creatures. She has a PhD from Cambridge
University's zoology department, is a Fellow of the Royal Society of Medicine
and has been a member of the Animal Procedures Committee since 1998. She is a
scientific adviser to the BUAV and the Dr. Hadwen Trust for Humane Research,
which researches into alternatives to using animals in medical research.
'Even for people opposed to all animal experiments, xenotransplantation
research is a particular cause for concern. The point about any new research
area like this is that it is going to grow. In particular, it will use more and
more animals - either as the research progresses or if the technique is ever
perfected. This is a direct contradiction of the general trend, which is to
reduce the number of animals used in scientific procedures.'
Though they welcome the fact that primates will never be used as source organs,
the BUAV say the numbers of primates used in experiments is indefensible.
'There has been a move to cut down on the number of primates in all areas of
medical research, so the number used in xeno procedures is very high by
comparison. In addition, the scientists are encountering new problems with the
research all the time. This is a terrible waste of animal lives,' says Dr.
The BUAV claim that primates used in xenotransplantation research will
experience a large number of traumatic procedures, including major surgery,
from which many will die; internal haemorrhages; isolation in small cages;
repeated blood sampling; wound infections; nausea, vomiting and diarrhoea
because of immunosuppressant drugs and kidney or heart failure.
'It's not just the suffering they endure in the laboratories and research
establishments,' Dr. Langley explains. 'Just getting there can be torture.
Studies of primates show them to have complex mental abilities which may
increase their capacity to suffer. Supplying the laboratories in the UK imposes
huge suffering on the animals. It involves capturing wild individuals, usually
in Africa. They're then contained in small, single cages, and transported for
very long distances causing deaths, distress and suffering. A number of
inquiries have said that the use of primates was unacceptable and should be
limited to very small numbers. Our view is that any number is unacceptable.'
Critics also claim that the animals are treated cruelly and the experiments are
still a long way from succeeding - both claims fiercely denied by the companies
Xeno researchers say they are forced to use primates for some of the research
because of their genetic similarity to humans. They say that all humans have
pre-programmed antibodies against pigs, and only apes and certain types of
monkey have the same immune system as us. Therefore, only these animals can
demonstrate how a human might react to a pig organ.
In the UK scientists have had their homes firebombed by animal rights
organisations whose views and supporters are more extreme than the BUAV, and
regularly receive death threats. In public they say little for fear of
attracting more attacks, but Dr David White, whose research at Imutran has been
crucial to modern xenotransplantation, defends the work staunchly.
'As far as the animal rights activists are concerned, I accept that they have a
fight to reject animal experimentation. I accept they have a fight to reject
for themselves the product of medical research on animals. But I don't accept
that they have a fight to prevent the population at large from benefiting from
what that research can bring. And even an animal rights activist, when he's
sick, goes to the doctor and says "Help me".
'If the animal rights people had their way, they would stop all progress in
medical research. There is not a single medical advance that's currently being
placed in hospitals that hasn't gone through animal research. You stop animal
research, you stop medical advance, it's as simple as that. I find that an
unacceptable position for anybody to take up.
'The regulations under which we conduct our experiments here in the UK are the
strictest anywhere. Everything we do is licensed by the Home Office. Their
inspectors regularly come and watch what we do and comment on the way that we
do it. Not only am I satisfied that the animals' suffering is kept to a
minimum, the Home Office inspectorate are also satisfied.'
In the US, doctors and scientists working in this field express their views
even more openly. In an operating theatre in Ohio, doctors carry out
experiments on monkeys similar to those performed in the UK. Looking down on
them from the wall is a poster. It shows a photograph of a sick child, with the
caption, 'The animal rights message to someone suffering from a deadly disease
- tough luck!'' The differences between the two sides in this debate are
Few of the arguments against using primates for source organs can be made
against using pigs. Man and pigs have lived together for thousands of years and
pigs were among the first animals to be domesticated. Cave paintings of boars
survive from ice age Europe, dating from between 35,000 and 20,000 BC. In the
Bible, Noah took two pigs onto the Ark to escape the Flood, which scholars
estimate happened about 13,600 BC.
Charles Darwin's On the Origin of Species claims that the Chinese
had domesticated pigs by 7000 BC and swine feature regularly in Greek
literature. Closer to home, at the time of the Domesday Book the size of some
settlements in Surrey and Sussex was calculated by the number of pigs they
We haven't only lived alongside pigs - there is a long history of using parts
of pigs, including tissue, to help sick humans. Pig heart valves have been
implanted into humans for more than twenty years, and since the 1930s pig
insulin has helped millions of people with diabetes live more normal lives. Pig
skin grafts have been used for burns victims for many years. This long history,
say supporters of the xeno project, illustrates that there has been ample
opportunity for men to contract dangerous pig diseases, but that very few have
Despite all this close contact, nature can still spring surprises. In 1999 a
virus never seen before in pigs infected a large number of pigs in Malaysia. At
least 117 people who worked with pigs died. More than a million pigs were
slaughtered to try to contain the virus, and thousands of people fled the
At a practical level, pigs seem to offer the most hopeful option as source
animals because they are anatomically and physiologically similar to humans.
Their kidneys, hearts, lungs and livers work in a broadly similar way to
There are estimated to be about 7,000 million pigs in the world at any one
time. When a pig is born it's about the size of a man's hands. Within five
months it's torso is as big as a man's. At this stage a pig's organs are the
optimum size for transplanting into humans. This is an important advantage of
the pig as a potential organ source - it's the right size.
Sheep and goats are too small and cows are too big. There are also fewer
ethical objections in using animals already bred in captivity for food. 'It
cannot be right to breed pigs to make people fat, but not to save their lives,'
says one researcher. 'Any objections to using pigs for medical procedures
should start at the breakfast table, not the operating table,' says another.
The ethical arguments against using primates for xenotransplantation are
therefore not as strong when applied to pigs. In the balance of the rights of
the animal to be free from harm versus the rights of humans potentially to live
longer or better by exploiting it, the pig has fewer supporters than the ape or
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