Mike Bebernes
·Senior Editor
January 22, 2022·
What’s happening
Doctors in Maryland earlier this month completed the world’s first heart transplant using a heart that came from a genetically modified pig. The experimental procedure, performed on a 57-year-old man with a terminal heart condition, is seen as a major breakthrough in the burgeoning field of cross-species organ transplants.
The heart transplant came just a few months after two teams of scientists broke new ground in separate experiments testing the viability of pig kidney transplants conducted on brain-dead bodies that had been donated to science.
The theory of animal-to-human transplants, known as xenotransplantation, dates back hundreds of years. Only recently, though, has that goal appeared to be within reach. Advances in gene-editing technology now allow scientists to overcome what was once an insurmountable barrier to cross-species transplantation: The human immune response that recognizes and attacks foreign tissues in the body. The heart used by doctors in Maryland came from a pig that had 10 separate gene modifications, including pig genes that were inactivated and human genes that were added, to prevent the recipient’s body from rejecting the organ.
Researchers hope these experiments prove to be the early steps of a process that ultimately turns animals into a viable solution to the severe organ supply shortage, which leads to thousands of deaths in the U.S. each year. Even though a record 41,000 organ transplants were conducted in the U.S. last year, more than 100,000 Americans are estimated to be on the transplant waiting list. An average of 17 people die each day waiting for an organ transplant.
Why there’s debate
The case for continuing to pursue research into xenotransplantation is straightforward. If science advances to the point where animal organs are a readily available option for human transplants, it could prevent countless deaths worldwide every year. In the eyes of the scientists, the value to humans would outweigh the harm caused to animals. “People talk about the ethics of doing the science,” one researcher told Nature, “but I would also argue that we should consider the ethics of not doing this science.”
Animal rights groups, unsurprisingly, oppose the idea of using animals for human transplants. “Animals aren’t toolsheds to be raided but complex, intelligent beings,” a spokesperson from People for the Ethical Treatment of Animals said. Others question the ethics of creating a class of animal for the sole purpose of slaughtering them to harvest organs. Some also argue that there is a lot that can be done to increase the supply of certain organs, like kidneys, from human sources that wouldn’t require anyone to die.
There are also concerns about the process of creating transplant-ready animals in the first place. Many bioethicists say creating creatures with both human and animal genes raises complicated questions about where the line between human and beast really is. They also call for strict guidelines for how much human material a creature can have before it starts to deserve considerations that wouldn’t be afforded to regular animals.
What’s next
There are still enormous scientific, logistical and legal obstacles that will have to be overcome before animal-to-human transplants can become a realistic option for the typical transplant patient. Most experts say it will likely be several years before xenotransplantation will be conducted outside of scientific research.
Perspectives
Supporters
A future where no one dies waiting for a transplant is worth pursuing
“The door to using bioengineered nonhuman organs has been opened — and with it, the promise of an almost unlimited supply of donor organs could follow.” — Jonathan Reiner, CNN
Transplants are close to harmless when compared to livestock slaughter
“The place to worry about animal welfare is breakfast, not the medical use of pigs.” — Art Caplan, bioethicist, to USA Today
Xenotransplantation can help reverse racial inequities in who receives transplants
“A Black, Asian or Indigenous person is less likely to get an organ donation than is a white person. ... Xenotransplantation has the potential to further democratize organ donation.” — Sylvain Charlebois, Ottawa Citizen
Human lives are simply more valuable than animal lives
“I can’t think of any reason to oppose this approach — assuming safety and efficacy — unless one is an animal-rights believer who thinks that pigs have equal value to humans. But they don’t. A rat is not a pig, is not a dog, is not a boy.” — Wesley J. Smith, National Review
The organ shortage creates its own, much more profound, ethical issues
“Treatment should be allocated equitably. Doctors are not qualified to distinguish 'sinners from saints,' nor do we think they should be deciding which patients are more deserving.” — Dominic Wilkinson, Conversation
Skeptics
Killing animals for human needs is indefensible in all cases
“The practice of breeding, raising and killing pigs for our purposes is deeply problematic as well. Pigs have consciousness, emotionality, bonds of care and more. This is more than enough to render the practice of breeding pigs for xenotransplantation massively harmful for pigs, even if the practice is beneficial for some humans.” — Jeff Sebo, Chicago Tribune
Gene editing raises troubling questions about the line between humans and animals
“Receiving a pig kidney won’t magically transform anyone into Babe, but what about a pig liver? Or better yet, a pig heart? You know the slippery slope — today it’s just a pig kidney, but tomorrow, we’re all galloping across the Island of Dr. Moreau. That’s a little dramatic, of course, but fears about violating the barrier between humans and animals are enduring and inexorable.” — Peter McKnight, Vancouver Sun
Major ethical questions are being ignored in pursuit of a medical breakthrough
“Assuming that pigs are the future of xenotransplantation assumes that there is no ethical problem with creating a new form of animal farming predicated on genetic modification and on-demand slaughter for spare parts. And yet a surprising number of medical professionals, bioethicists, and the media covering xenotransplantation have been mum on the subject.” — Jan Dutkiewicz, New Republic
There is a lot that can be done to make organs more available without killing animals
“Mostly, the development makes me sad that humans have been so unwilling to step up and donate kidneys to each other — or create the policies that would encourage such an act — that they are resorting to taking them from another species. Donating a kidney is a routine, safe procedure, one that humans could and would likely be more willing to provide if compensated.” — Dylan Matthews, Vox
The debate changes depending on which organ is being manipulated
“It seems likely we’d view an animal with brain or reproductive cells from a human differently than one with, say, human liver cells. In those cases, the ethics of ‘humanization’ start to become more meaningful.” — Nathaniel Scharping, Discover
There are serious ethical challenges concerning humans involved in the research too
“There is no question that using pigs as organ sources is the future. ... But first efforts often fail. Those brave enough to jump into the unknown need to be especially clear that they went forward at the right time and with the right patient, who fully understood the risks involved.” — Multiple authors, Washington Post
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