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.

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 across.


He is a virologist at University College, London.

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 medicine.

...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 conditions.

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 care.

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 for xenotransplant?

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 primates.


He is Chief of Transplant Services, Papworth Hospital, Cambridge England.

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 population.

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 experimentation.

...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.

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 pork sausages.

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.