This transcript has been edited for clarity.
I'm Art Caplan at the Division of Medical Ethics. I'm at the NYU Grossman School of Medicine in New York City.
My school, NYU, has been working for some time to try to develop alternatives to human organs from cadavers to permit more transplants to take place in the United States. There is still an enormous gap between the number of people who need transplants and the number of people who donate organs upon death.
Some people donate kidneys when they're alive, but we still need hearts, livers, lungs, and in the emerging world of transplant, potentially other organs — such as fallopian tubes, uteruses, or other body parts — that might benefit those who have been born without them or underwent cancer treatment and had them removed. The bulk of attention is obviously on the lifesaving organs, and we're still very, very short in supply.
One idea is to use organs from animals. For those of you who have tracked the history, there were efforts way back in the 1980s to try to use primates — to use baboon hearts or chimp hearts — and sometimes in children, but they didn't work. The organs were rejected, and the hearts were not the right size to maintain function in an adult because primates are too small. There's even an ethical issue that continues to arise about whether they're too close to us in terms of intelligence to permit sacrificing them to try to save humans. They're very expensive to raise, I might add, and they don't breed that often.
In recent years, decisions have been made to move away from primates and to go toward pigs. Pigs are roughly sized like an adult human. They can be up to 350 lb. The physiology looks fairly similar in the solid organ area to what humans have. We're breeding billions of pigs and eating them constantly, so it's not as if saying, "Let's use pigs" is going to result in any significant increase in the sacrifice of these animals.
If you're interested in animal rights, you're probably better off turning toward trying to change behavior at breakfast than you are trying to change behavior about organ transplants. We need thousands of organs for transplants. It's not a huge number of animals. Plus, if we get the pigs, it's likely that they'll be treated especially humanely. You don't want them stressed or sick. This is not factory farming of pigs like is used frequently to make bacon. These animals have to be treated superbly before they're sacrificed to get their organs.
The main trick, as many of you know, is to try to genetically engineer the pigs from birth so that their organs are less immunologically resistant to the human in which they're going, because the human body rejects foreign tissues. Unless you're an identical twin, even with human organs, we have to use a variety of drugs to try to keep them working because the body wants to fight them off. It thinks they're invasive, dangerous, infectious agents.
Some centers are moving faster. The University of Maryland has now done two pig hearts, not for research, but as a way to try to rescue someone who they said was not eligible to get a human heart. Lawrence Faucette, the second person to get a pig heart at Maryland, recently died after 6 weeks with a pig heart.
The FDA had given permission, along the lines of, "This is a desperate situation. If you think you can put it in, there's not going to be a human heart for him, and if you think it might benefit him in the longer run, then do it." He lived only 6 weeks.
Many people will ask, "Did he know — and did he consent — when he took this heart that he might not make it?" I'd have to say, yes, he understood that. That's not the only question. Are we in a situation where we know the science well enough yet? Have we done enough animal-to-animal transplants to see what rejection might occur?
At NYU, I proposed a model where we ask the next of kin of people who've died to let us put artificial organs or pig organs into the dead body for a short period of time to see the impact of being transplanted, both on the human recipient and on the transplanted pig organ. It's a model that will teach us much without having to take gambles with causing a large amount of suffering to a human who's rejecting a pig heart.
I'm not sure that we're ready to do what Maryland is trying, which is to say, "There's never going to be a human heart. All we have got is this genetically modified pig heart. Do you want us to try to do this?" Desperation goes into that answer, with people saying, "That's all I've got. Try it."
It isn't likely that you're going to live very long with the first pig heart experiments, particularly as we don't fully understand the best drugs to use and the best approach to take to make that heart work. I think it's also the case that we can still learn from animal-to-animal transplants and studies on people who are brain dead, whose relatives agree to let them volunteer to be used for a period of time to study what's going on.
It sounds terrible from the point of view of an individual who's got no choices, who might say, "Well, try the pig heart." Unless we can learn — remember, the pig heart efforts so far have just been desperate efforts to save people, and they're not even designed as a clinical trial — and unless we can really say there's some chance that you're going to live for more than a month or two and we're not going to make you die more miserably through rejection… I'm sorry to say it, but we're not ready. We don't have what we'd like to have to rescue you.
It's a bitter truth that, as much as we want to help and as much as medicine wants to offer something when death is imminent, we don't always have the tools. We don't always have the knowledge ready to go. It's a hard thing to admit, but I don't think we're quite there yet in terms of moving pig organ transplants into anything other than experimental clinical trials.
I'm Art Caplan. I'm at the Division of Medical Ethics at the NYU Grossman School of Medicine. Thank you for watching.
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Cite this: Pig Organs in Humans: The Science Is Not Ready Yet, Says Ethicist - Medscape - Dec 04, 2023.
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