“Transplanters are betting that if we can perform xenografts in good conditions, it will save thousands of lives”

1920, Paris: transplant of great ape testicles onto humans in the stated hope of “revitalizing” them. 1963, Louisiana: transplant of a chimpanzee kidney into an African-American patient. 1984, California: baboon heart transplant into a ten-day-old newborn. Three xenograft experiments, three failures. The idea of ​​transplanting an organ from an animal to a human has a long, fascinating history, deciphered by sociologist Catherine Rémy*, whose book “Hybrids» has just been published by Éditions du CNRS. Is it about healing or transforming the human species?

Madame Figaro. – Where does your interest in grafting between different species come from?
Catherine Rémy.– I have been working on human-animal relationships for a long time. I did a thesis on animal killing, investigating in slaughterhouses and experimentation labs. Scientists had spoken to me about xenografts, that is to say the transplantation of organs between different species, particularly between animals and humans. I found it quite crazy and destabilizing. And there were very few studies on the subject.

As early as 1667, blood transfusions between animals and humans were attempted in France…
It was for the first time an attempt to use the resources of the animal body to treat the human body. But the concept of organ transplantation only appeared at the end of the 19th century.^e century and early 20th^e century. With the idea that animal bodies are available, like depots of spare parts for the human machine. While those of humans are inviolable: at the time, it was unthinkable to remove organs from them, it was taboo.

In the 1920s, in France, there were dozens of attempts to transplant great ape testicles into aging men!
It was the Roaring Twenties, we tried a lot of things. Serge Voronoff, a doctor of Russian origin, was interested in hormone therapy and opotherapy (treatment of diseases using cells of animal origin, Editor’s note), then in vogue: animal substances were ingested to invigorate the human body. He also showed that great apes have almost the same blood groups as humans, proof of proximity and compatibility. He therefore imagined taking their testicles and attaching them to those of men. Adding this animal gland would revitalize the hormonal system, leading to individual rejuvenation. With the idea that if we were able to source primates on a large scale, we could revitalize society as a whole. Even, as an associate of Voronoff stated, to carry out a eugenics project: the body of primates, considered wild, powerful, uncorrupted, would make it possible to create a “new humanity.” This caused controversy, Voronoff ended up being discredited. Moreover, his grafts were not really grafts, because they were not vascularized.

When did the first “real” xenografts date?
From the 1960s. After the Second World War, attempts at allografts, that is to say transplants between humans, particularly kidneys, within families, failed. The idea of ​​xenografts therefore resurfaced. In 1963, in Louisiana, United States, chimpanzee kidneys were transplanted into African-American patients. A young teacher survives eight months, which is then seen as a success. In 1964, in Mississippi, a chimpanzee heart xenograft caused an outcry because the man, a deaf-mute living in a trailer, died immediately.

The body of primates, considered wild, powerful, uncorrupted, would make it possible to create a “new humanity”

Catherine Rémy

In 1984, in California, a baboon heart transplant into a newborn suffering from a congenital anomaly also failed…Yes, another failure and a major, highly publicized controversy. The controversy concerns the fact that this is again a very vulnerable patient, but also that the bodies of healthy animals, particularly primates, cannot serve as a reservoir for humans. Animalist criticism is gaining momentum, and winning public debate. This is a turning point: a quasi-moratorium is decreed on xenografts. Especially since in the meantime, modern resuscitation techniques have led to a new definition of death, brain death, which can occur while the heart is still beating, thus paving the way for the removal of moral reluctance which prevented to harvest viable organs from humans.

Where are we today?
Doctors commonly use pig tissue, heart valves or skin. But whole organ xenografts are still not a therapeutic reality, because of the massive and rapid rejection of organs from animals. Researchers have been trying to overcome this for around 30 years. Trials of transplanting pig organs into primates have shown promise, so surgeons are moving back to clinical trials in humans. A genetically modified pig heart was transplanted into a patient in the United States in 2022. Several other trials have taken place since then, with survivals of a few weeks. Transplanters believe it, and it could work very soon. The key is to know what controversies this will arouse, because it will inevitably arouse some.

What could they be about?
Animalist criticism, which concerned monkeys, could also concern pigs. Especially since they have been “humanized”: human genes have been introduced to them to make them more compatible and to avoid rejection. Transplanters are betting that if we can perform xenografts under good conditions, this will resolve the issue of organ shortage and save thousands of lives. But this will produce controversy.

What does it mean to live twenty years with a pig’s kidney or heart? Is this the same as having an artificial heart?

Catherine Rémy

There are also fears of possible “transformations” of transplant recipients. Do these practices risk blurring the boundaries between species?
Whether fantasized or not, this question has always been asked. She will rest. What does it mean to live twenty years with a pig’s kidney or heart? Is this the same as having an artificial heart? Between humans, the transfer of organs already raises questions among transplant recipients, with this idea that “the dead person lives in me.” This disorder could be increased tenfold by the fact that it is a non-human who is “in me.” Symbolically, it’s not nothing.

You immersed yourself in a laboratory of xenografts from pigs to primates. Why was it difficult?
The researchers were very afraid to open their doors to a non-transplanter, even though I assured them of strict anonymity. They had reason, as scientists had been threatened in the 1990s in the United Kingdom. But they ended up letting me into the laboratory, where I understood all the complexity of xenografts, both moral and technical. This therapy is supported by scientists, surgeons and patient associations convinced of the benefit it can represent for humanity. But public opinion is less and less ready to accept it, because the question of respect for animal life is more and more present. To decide, there will need to be a real social debate.

 Catherine Rémy is a research fellow at CNRS and EHESS. Just published: “Hybrids. Transplanting organs from animals to humans”, CNRS Éditions, 296 p., €25.