In these excerpts from FRONTLINE's interviews with xenotransplant doctors and
researchers, they discuss their belief in the critical need to use pigs and
nonhuman primates in xenotransplantation and other medical research.
He is Chief of Cardiothoracic Surgery,Ohio State University
Medical Center, and is involved in experiments implanting pig hearts into
Is it possible for any of this xenotransplantation research to proceed
without animal experiments?
Absolutely impossible, in my opinion, to proceed with human implantation
transplantation of a pig organ without animal experimentation. It is absolutely
necessary. And not something that I consider lightly. It's something that as
as an individual who prizes human life beyond all else, but appreciates animal
life and welfare as well.
I must admit that this is an issue that in my mind has absolutely no
equivocation. Human life is what I am designed to help and it's something
that I understand in a very intimate way. For me to take any therapy and use
it on a human requires that I understand how that therapy is going to impact in
a biologic environment. And there is no surrogate, there is no test tube,
there is no alternative milieu that will permit me to understand the behavior
of anything if it's not in an animal first, before going to a human. And even
if it's done in an animal first, it isn't going to mimic the human condition
precisely, but it is the best alternative that we have.
Let me draw some examples. The ability to use the heart and lung bypass
machine that is a life-saving tool that allows us to do all forms of heart
surgery. That would not have been possible had we not understood it first in
an animal environment. The ability to perform a valve heart surgery, and to
know that a valve will be durable, will last, be safe, must be performed in an
animal environment. Animal research was the cornerstone for the discovery of
insulin, and there are literally thousands of examples from therapeutic drugs
for the treatment of AIDS, for the treatment of cancers, drugs for treatment of
infectious disease, all of which require a non human biologic environment that
mimics as best as possible the human condition.
He is professor of medical ethics at Tufts
Medical School and the Goldthwaite Professor in the Tufts Philosophy University
Department. In 1998, he joined others in calling for a moratorium on
xenotransplants pending further public discussion.
Why aren't we seeing an uproar of concern among animal rights in the U.S.
You know, it's interesting that animal rights activists who have a history of
being quite militant in this country with regard to say use of animals for furs
or cosmetics, are not saying anything about xenotransplantation. And I think
it's actually quite wise of them not to say something. They have nothing to
gain by saying something here. They're dealing with a line of research that
has great promise of saving human lives. And I don't think the animal
activists will be in a good position if they have to come out and say these
animal lives are worth more than human lives.
There are many other cases where we mistreat animals for what may be thought of
as frivolous human purposes where the main point of their message can be gotten
He is a virologist at University
Is it possible to move forward in this area of science without animal
Can we make medical advances and save lives without using animals
experimentally? Well, in some small areas of medical research we can. But
it's my opinion, as is the case for most medical researchers, that some use of
animals has been absolutely essential for the progress we've made to date.
There is no drug that's licensed for use that hasn't been tested for toxicity
in animals and, quite frankly, I prefer them to be tested in mice or rats
before use than tested in my grandchildren. There are no vaccines today that
haven't been tested in animals. We would not have eradicated smallpox and
could not now be eradicating poliomyelitis without the use of animals. Even
today, every batch of polio vaccine that is used, that is released to give to
babies must be tested on animals first, to check whether it's reverted to
so-called neuro virulents, whether it could become paralytic. Animals are
absolutely essential if we are not going to revert back to Stone Age
...Having said that some use of animals is essential for medical progress, I
do think we need very stringent regulations to make sure we don't abuse animals
any more than is necessary. Not all the procedures are pleasant for animals,
many of them have to end in the death of the animal, and all this must be done
in a proper manner and the animals must be treated as humanely as possible.
Cruelty has absolutely no place in medical research and, therefore, I'm
pleased that I work in a country, here in the UK that has amongst the most
stringent regulations in the world. I edit one of the cancer research
journals, and we simply will not accept papers for publication that describe
animal experiments that are not in concordance with our national and
international guidelines and codes for animal husbandry and humane
Nonetheless, the bureaucracy of applying to use animals in medical research has
grown too cumbersome. I don't mean that the ways in which we handle them
should be relaxed, but I think the speed at which the projects can be reviewed
and licensed and more generic ways of licensing such simple procedures as
immunising an animal, giving it a jab, just as you would a baby could be er,
made very much simpler without relaxing the very strict standards in animal
And we are tending in this country, with its very vocal so-called Animals
Rights Movement which is really just dead against the use of animals for
anything to go too far the other way. And that is why I signed, amongst many
other scientists, a letter [to The Times of London] requesting that these
procedures should be reviewed, not to relax them, but to make them more easily
conform to routine procedures.
...Why do you think we moved away from primates as a source of organs
Well, we could well ask why are we using pigs and not animals that are much
more closely related to us, such as using monkeys or other primates as sources
of tissues. And there are several good reasons for that.
First of all, we don't like the idea of using our close relatives as organ or
tissue banks. Second, there are not enough primates to go round. And those
that can be bred in captivity like Macaque monkeys, tend to be rather small for
whole organ transplantation. Third, primates probably have as many or more
viruses as pigs do, some of them may more readily transfer across into humans,
and because they're not a farm animal that has been used for so many years,
veterinarians know much less about their viruses. The ones we do know about,
we know about some that can be quite nasty, even lethal in humans.
Above all, I think, if xenotransplantation became not a routine medical
procedure but one done on thousands or hundreds of thousands of patients, we
need a ready supply maintained in a clean environment. That is going to be
very difficult to achieve with monkeys, and certainly quite impossible and
unethical with apes. We have bred pigs as farm animals for thousands of years.
Generally speaking, there are no ethical objections to rearing pigs for meat.
Pig heart valves which are inert pickle tissues but, nevertheless, derive from
the pig heart, have been used for 30 years in heart operations, and even those
religions that forbid the consumption of pork as meat, Hindus, Moslems, Jews,
do not object to the use of pig heart valves for transplantation.
So we have an existing body of acceptance for the use of pigs. We can breed
pigs easily, they grow to maturity to within a year or so, each litter has many
piglets. So with these special transgenic pigs it's going to be possible to
build up a bank for human xenotransplantation much more readily than with
He is Chief of Transplant Services, Papworth Hospital,
Why have monkeys been used?
Precisely as I said, this genetic construct was made for humans, and the
nearest match we could get, if you could call it that way, to use these
constructs was in monkeys.
Do we have a right to use animals in this way?
Yes, I can't see why not.
To open the chest of a monkey and place a pig's heart in it?
Sure. Animal experimentation for progressing science and progressing medicine
has gone on for years. And there are certain experiments one has to do. I
don't think there's an issue in terms of rights. I think it's a perfectly
reasonable and sensible way to approach answering some scientific questions
that would then enable us to progress issues to do with medicine for the
How can you assure people that the sufferings that these animals go
through is kept to a minimum?
Well, there are very interesting and tight regulations, particularly in the UK
about animal experimentation, but I think these experiments are extremely
delicate and, indeed, expensive. And we want to treat the animals in the same
clinical way we treat humans. And it's not in anybody's benefit for them not
to be treated in a very high class way. So the operating rooms are like
operating rooms we use for humans. The care we give these animals is as near
as we possibly can to the way we do with humans. And I think that we have to
answer some very basic scientific questions.
We can't, clearly, sensibly go from an idea to producing the pig organs to go
straight in to humans. That would be, I think, a highly irresponsible way of
dealing with issues. So we have to go and do animal experimentation, which I
can see no particular problems with.
What do you say to the animal rights activists who regard what you're
doing as unnatural and abhorrent?
Well, they have their opinion and their view, and I think if the whole of the
community decided that that was what the case would be, we'd be living in a
different society. Most of every day medicine that you have now, the benefits
of living in a community we live now, has been a result of some form of animal
experimentation, and there will always be people who have these beliefs. And I
think that's perfectly reasonable. And I think there are people who are
concerned about animal welfare, and that's perfectly reasonable. I think when
people go around destroying people's houses and bombing scientists and making
life intolerable, that's particularly unreasonable. And in a society where we
like to provide modern medicine, when we like to see people suffering assuage,
then we have to say this is part and parcel of the society we live in, which is
...What about the fact that preparing pigs for transplantation involves
preparing them in bio secure units, and very much controlling their growth from
the moment they're born.
I think that that is initially to avoid infections from the derived pigs, but
once they're in their community and their environment, they breathe perfectly
normally and live perfectly healthy lives. In fact, they're very well looked
after. A lot of work has gone in to making sure that's the case. What you do
not want is pigs that are not pig like, not happy being pigs, and not healthy.
This doesn't help anybody in terms of producing good quality organs. And these
pigs are extremely well looked after.
He is assistant Director of Transplantation at Baylor
University Medical Center, Dallas. He was the surgeon involved in the pig
liver "bridge" which saved Robert Pennington's life by filtering his blood
while he waited for a human liver transplant.
I think it's absolutely essential that we try to solve our problems in our
species, but we know that humans can't solve all their problems, we live with
other species, we have to use them as a food source, and now we're extending
that to say that we need their help in order to improve our lot, to mediate
pain and suffering.
What I would say to those people is that we want to reach out to them, we want
them to be a partner with us. We know that we need to use other species, we
want them to help us to do it in the right way. Just as we would for food,
material, let's work together to try and do it with the highest ethical regard
for ourselves and for animal species...
Do you see an intellectual hypocrisy here, where on the one hand some of
us are prepared to eat another--
I see that we have difficulty reconciling what we, as one species does, and I
understand the anger and the anxiety that these people have. I'm not angry at
them, I think our job is to try and educate and to try and explain to them why
we're doing it, that we want to help people, we don't want to hurt animals, we
want to treat them humanely. We know that, as I said, we have to use the
animals for a variety of different reasons, whether it's for clothes, whether
it's for food, and now whether it's for organs. No, I think that we as humans
have difficulty coming to grips with things.
Many people draw a line in the sand at one place, and they have difficulty in
dealing with one totally different mind concept. It's our job to try and work
with them and to explain to them what we're doing, why we're doing it, and why
we believe it is an ethical....
Some people would say that you, personally, are responsible for damaging
almost in a sacrilegious sense the traditional customs, cultures and religions
of the world, because imagine the Islamic individual. You're suggesting that
that person should take an organ from an animal that they for centuries have
regarded in a particular way.
Well, that's an excellent question. I come from the Jewish religion so I've
had this dialogue with rabbis in Israel about this very question. I'm not and I
don't proclaim to be a theologian or an expert in religion.
But within all religions, whether it's a religion of Jesus Christ or of
Mohammed or a religion of any deity, it is stated within all those religions
that to save a life is the greatest good and all other aspects of the
religion are subservient to saving that life. In my dialogue with both people
of the Islamic, Jewish religion and the Christian religion, we see no problem
and the theologians see no problem with what we are doing. Jews will accept
organs from pigs as long as they're not eating them, the same as the Muslims,
that if they are being used to save the life it takes precedence over all other
aspects of the religion.
He is professor of surgery at Harvard
Medical School and director of Transplantation Biology Research Center at
Massachusetts General Hospital.
There are those who feel that we do not have the right to use animals in
this way for our own benefit, to prolong our own lives. What do you say to
I've already explained to you that xenotransplantation between closely
related species, through this tolerance procedure, through mixed chimerism
can work. In fact, we know that it does work, and we have a synamologous
monkey with a baboon kidney now for two years, who's tolerant, hasn't needed
any immuno suppression, since day 28.
So, a closely related species would certainly be a lot easier to be used as a
donor than a distantly related species. But, the only really closely related
species that would be a potential donor for transplants to a human being would
be chimpanzees or apes, both of which are endangered species, and I don't think
any of us, or anyone in his or her right mind would consider using such animals
as donors for transplantation. And there, I think, the argument of not wanting
to use an endangered species makes a lot of sense, and I think that most people
can understand it.
But, when we're talking about using pigs as a donor, pigs are being used as a
source of food throughout the world, and our societies have determined that
it's alright to use pigs as a source of food. And it's hard for me to
understand how it would be unreasonable to use a heart from a pig, for example,
to save someone's life, if it's alright to use the pigs to produce bacon and
Are there also animal welfare issues that spin out of this, if in the future
we will intervene in the lives of these animals, and make them live in very
unusual ways in order to benefit us.
Well, I believe firmly in humane treatment of animals. I think there's a big
difference between humane treatment of animals and, quote, animal rights. I
think we have determined that it is reasonable to use animals to sustain human
life, and I think that that does not change in any way the need to always treat
animals humanely. We would not want any of our animals to suffer, and I think
that everyone working in this field feels the same way.
But the public will have to accept, will they not, that animals will have to
live in unusual conditions, so that they can be absolutely clean and pathogen
free, in order to donate their organs for us?
Donor pigs for transplants, will definitely have to be maintained in very
clean environments, in order to avoid the possibility of carrying an infection.
But the conditions can still be quite humane and quite reasonable, much more
reasonable, I'm sure, than many situations in which animals are raised as a
source of food.
And likewise, the public will have to accept that we will intervene in the
lives of these animals at very crucial stages, won't we, in the fertilization,
the ovulation, the birth of these animals, we will have to manage and farm them
specifically for their organs, won't we? It's not farming in the traditional
sense is it?
It's not farming in the traditional sense, but I don't see anything about it
that would be inhumane or which would cause the animal to suffer. I would not
condone such a practice.
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