Will Pig Organs Be Used for Transplants?

Arthur L. Caplan, PhD


November 29, 2017

Hi. I'm Art Caplan, and I'm the director of the Division of Medical Ethics at NYU School of Medicine.

If you needed a transplant, would you accept an organ from an animal? Specifically, would you think about taking a heart, liver, or kidney from a pig?

Why a pig? Well, pigs, to be blunt, are Homo sapiens horizontal. They are about the same size as many of us, in terms of weight. Their physiology resembles ours, and it has been the dream of many scientists to address the huge shortage in organs by somehow coming up with xenografts—the use of animals as sources of organs.

The history of using animals as sources of organs has not been distinguished. Efforts were made years ago to try to use a baboon heart in a baby. Other people have tried, sometimes [using] pig organs; they have not worked. Immunosuppression has not permitted these organs to function well.

A major fear, in addition to finding out how to keep the organs from rejecting, is what about transmitting diseases that animals have and giving them to people? There are plenty of viruses in pigs, and they would not do well for an immunosuppressed human; they would probably kill that person. Plus, if that human being went out and sneezed, coughed, excreted, and sweated, then maybe those viruses would be dumped into a home environment or public environments and we would inadvertently cause epidemics.

Normally, when we eat a pig (say, as bacon), it has to pass through our stomachs and digestion kills these things. But if you put the organ directly into contact with the bloodstream, the viruses that we fear are going to escape.

Well, [there are] two bits of good news. One, immunosuppression is getting better. We are starting to be able to understand how to prevent rejection using the drugs that we have, and some new ones as well. And it is becoming possible to use genetic engineering—the new gene editing techniques known as CRISPR—to try to make pigs in which these viruses have been wiped out. That is, engineering the viruses away in the pigs, thereby preventing any risk for transmission.

I think it's going to be possible to both engineer the viruses out of pigs and then clone the animals, so that you get the same ones again and again. I do think there is a fairly good chance, even though things have not worked well in the past, that we might see pigs used down the road as sources of organs.

[There are] two big ethics questions. First, some people say, wait a minute—there are religions that are opposed to eating pork: for example, Orthodox Jews and many Muslims. There may be people who say, "I can't eat it; can I accept an organ from such a source?"

In talking to religious leaders from those traditions, what I hear them say is that if you can save your life, then you can overcome the prohibition against eating pork. It is also not clear that transplanting an organ into your body is the same thing as ingesting it into your digestive tract. I do think that objection would be overcome.

Even if it were not—even if there are people who say, "I am not going to deal with a pig organ," there would be less pressure on the human cadaver side to get those organs. So pig organs coming in would decrease overall demand and benefit everybody.

The other objection is, what about killing the pigs; is that the right thing to do? Well, I think it is. In fact, you really have to face the question head on: Is a human life worth more than a pig life? Although I don't think we should be cruel to the pigs, mistreat them, or stress them, the fact is that we do much better by pigs intended for transplant than we do factory-farming animals for dinner.

We do a lot of things to pigs and other animals that really aren't good for their health or their emotional and psychological well-being, but for transplant purposes, you would have one happy pig. You don't want any stress, you don't want any health problems, and you want that pig to be as healthy and as strong as it can be if you're going to use its organs to save a life.

Because I do value human lives more than I do animal lives, I'd make the trade-off. I think it's a close call, a grudging trade-off, but I'd make it, and at least I know that the pigs are well treated, because that's the way to get the best supply of organs.

Down the road, we may see pigs not only as something that appears on a menu, but also something that appears at a hospital as a choice of therapy.

I'm Art Caplan, at NYU School of Medicine, thanks for watching.

Talking Points: Will Pig Organs Be Used for Transplants?

Issues to consider:

  • In 2016, 116,592 people need an organ transplant, and more than 7000 candidates died while on the waiting list or within 30 days of leaving the list for personal or medical reasons, without an organ transplant.[1]

  • Some healthcare professionals say that using a pig heart, lungs, or other body parts could help relieve the organ shortage and save lives.

  • Every year, approximately 100 million pigs are killed for food in the US.[2]

  • Some healthcare professionals believe that using pigs for human transplantation is exploitation.[2]

  • Proponents say that the few thousand pigs grown for their organs would be anesthetized and killed humanely and represent only a small fraction of the total number of pigs killed for food.[2]

  • Pig heart valves already are routinely transplanted into patients.[2]

  • In the 1990s, it was found that pig DNA contained genes for viruses that resembled those that cause leukemia in monkeys. Research was halted because of fears that pig organs would infect humans with retroviruses.[2]

  • Scientists from Harvard University; eGenesis, a biotech company; and several other institutions were able to use gene editing and cloning to create virus-free piglets that could potentially be used in the future for human organ transplants.[3]

  • Baboon and chimpanzee kidneys were transplanted into humans in the 1960s, but patients died within a few months, usually because the immune system attacked and rejected the organ.[4]

  • Pig organs can be harvested on a schedule, so surgeries can be scheduled at exact times during the day, eliminating the need for emergency surgeries, planes to deliver organs, and surgical teams to be called in at any hour.[5]

  • If a patient with kidney failure could get a kidney the next day, large dialysis centers would not be needed and hospital beds in the intensive care unit would be freed up.[5]


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