Xenotransplantation

https://nyulangone.org/news/progress-xenotransplantation-opens-door-new-supply-critically-needed-organs

Vocab: matching

Match the following xeno- words with their definitions

1. xenophobia

2. xenophilia

3. xenobiology

4. xenolith

5. xenogenesis

6. xenotransplantation

a) the theoretical idea where offspring are a completely different species from their parents

b) a strong interest or attraction to foreign cultures / people

c) a strong dislike or fear of foreign cultures / people

d) a medical procedure where a damaged human organ is replaced by an animal's

e) the study of lifeforms that are different to the ones on Earth

d) a piece of rock which is trapped inside a different piece of rock

Discussion

Do you have this xeno- prefix, or something similar, in your own language?

Based on the words in the first task, what meaning does xeno- carry?

Have you heard of any popular stories about animal-to-human organ transplants?

Humans have been experimenting with xenotransplantation for hundreds of years. When do you think the first, successful*, whole-organ transplant happened? What animals / organs were involved?

*successful = the patient survived more than a few days

The Chimpanzee Kidney

In the early 1960s, doctors were already performing organ transplants, but there was a serious problem: there were not enough human organs available. Some surgeons began asking a remarkable question: could an organ from an animal keep a human being alive?

In 1964, American surgeon Keith Reemtsma and his team tried to answer this question. They transplanted kidneys from chimpanzees into six human patients who had severe kidney disease. At that time, this was an extremely experimental procedure. Doctors knew that the human immune system could attack an animal organ, but they hoped that chimpanzees might be suitable donors because they are closely related to humans.

Most of the patients survived for only a few weeks. However, one patient had an extraordinary result. She was a 23-year-old schoolteacher who had serious kidney disease. Doctors gave her chimpanzee kidneys, and they continued to work for about nine months.

During this period, she was able to return to her job and live a relatively normal life. This was remarkable because doctors had not expected an animal organ to work successfully inside a human body for so long.

Eventually, however, the woman suddenly became seriously ill and died. Doctors examined her body after her death and made an important discovery. The transplanted chimpanzee kidneys looked surprisingly healthy and showed no clear signs that her immune system had rejected them. The experiment was therefore both a success and a failure.

Discussion

I found it both surprising and expected to learn that the first successful case of xenotransplantation came from a chimp. Was it the same for you?

Why do you think we no longer use chimpanzees for xenotransplantation?

At times, I had a visceral (strong, feeling-based) reaction to the idea that a woman had chimpanzee kidneys inside her. Did you?

The woman survived for 9 months, which was considered a success. What do you think?

Now we'll read a much more recent case involving a different animal and a different organ.

Can you guess which ones are involved?

The Genetically Modified Pig Heart

For decades, scientists had dreamed of using animal organs to save human lives. One major problem was rejection. When a human receives an organ from another person, the immune system may attack it. The problem is even greater when the organ comes from another species.

In 2022, doctors in the United States made medical history by taking an important step towards solving this problem. On 7 January, surgeons at the University of Maryland Medical Center transplanted a genetically modified pig heart into a 57-year-old man called David Bennett. Bennett had severe heart disease and was extremely ill. He could not receive a normal human heart transplant, so doctors offered him an experimental procedure as a last chance to survive.

The heart came from a pig that had been genetically modified. Scientists changed several of the pig's genes to make the organ more compatible with a human body. They also used special drugs to control Bennett's immune system and reduce the risk of rejection. The operation was a world first. After the surgery, the pig heart began working inside Bennett's chest. For several weeks, it continued to function strongly, and doctors did not see the immediate rejection that they had feared.

Bennett survived for about two months after the operation. His condition later became worse, and he died on 8 March. Doctors did not initially give a definite cause of death. Although Bennett did not survive long-term, the operation was still considered an important scientific achievement. It showed that a genetically modified animal heart could function inside a human body for a significant period of time without immediate rejection.

Discussion

Bennett was the first man to receive a pig's heart, and it was as recent as 2022. Did you hear about this in the news?

Genetic modification used to generate a lot of outrage. This seems to have died down in recent times. Why do you think that is? Do you have any opinion on the matter?

Bennett survived for just 2 months. Do you think it was worth it for him?

Our next story comes from just a few days ago.

Did you see anything about it in the news?

The Pig kidney

In January 2025, American doctors performed an experiment that could change the future of organ transplantation. They gave a genetically modified pig kidney to a 66-year-old man called Tim Andrews. The remarkable part was not only that the kidney worked, but that it continued working for nine months while Andrews waited for a human kidney.

Andrews had end-stage kidney disease caused by diabetes. His kidneys could no longer clean his blood properly, so he needed dialysis. Doctors believed he might have to wait years for a suitable human kidney. For Andrews, this was a serious problem because long-term dialysis can be difficult and exhausting.

The pig kidney came from a specially bred Yucatan miniature pig called Wilma. Scientists had made 69 genetic changes to the pig. Some changes removed features of pig cells that the human immune system normally attacks. Other changes added human genes to make the organ more compatible with the human body. Scientists also changed the pig's DNA to reduce the risk of viruses being passed to the patient.

The kidney started working immediately after the operation. For 271 days, it allowed Andrews to live without dialysis. He could return to ordinary activities such as cooking, vacuuming and taking long walks with his dog. Eventually, however, the pig kidney began to fail. Doctors removed it, and Andrews returned to dialysis for 82 days. Then, in January 2026, he received a human kidney from a deceased donor. The human kidney worked well.

Dr Leonardo Riella, from the centre for transplantation sciences at Mass General Brigham said the shortage of organs available for transplant meant " we are in a crisis".

Discussion

In the 1960s, a woman was given a chimpanzee kidney and lived for 9 months. Tim Andrews' pig kidney also worked for about 9 months. One or two other cases have also reached the 9-month mark, but not longer. Is that quite disappointing?

When people see headlines, they often assume that humans are living full lives with animal organs inside them. That's not the case. Most have animal organs as a temporary measure while they wait for a human organ to become available. Were you aware of that?

In some countries, organs cannot be taken from newly-dead people unless they have explicitly given consent, i.e. with an organ donor card. These are called 'opt-in' systems. What do you think an 'opt-out' system is? Which system makes more sense?

the body rejecting an organ