How pig kidney transplants, as well as hearts, lungs and skin, could save many human lives

A pig’s heart beating in a human? This medical feat has already been achieved – at least for a short time. Kidneys from animals have also been transplanted. Last year, a 62-year-old man lived with a pig kidney for almost two months before he died of a sudden heart disease, as recently reported in the New England Journal of Medicine. There is growing hope that organs from animals can help ease the global shortage of donor organs. Research into the transfer of animal organs to humans, known as xenotransplantation, has been going on for decades. But such interventions have only been approved in isolated cases. The US Food and Drug Administration has now, for the first time, allowed clinical trials for the transplantation of pig kidneys. The biotech company United Therapeutics plans to include up to 50 people in the study this summer; the second company involved is eGenesis. The genetic material of the donor animals must be modified to prevent the organs from being rejected by the recipients. The animals are developed and bred for this purpose – not only in the United States, but also at the Technical University of Munich (TUM) and the Ludwig Maximilian University of Munich in Germany. Konrad Fischer, head of the TUM’s xenotransplantation section, explains how the genetic make-up of the donor animals is modified. Among other things, this involves certain sugar structures on the surface of pig cells, against which humans naturally have antibodies. The Munich researchers are “at the forefront worldwide” in these developments. Pigs are used because they initially show a high degree of compatibility to humans and are actually well suited in terms of anatomical structures Philipp Felgendreff, transplant surgeon “We could perform these individualised treatments in Europe at any time – we have the animals available, we have the know-how available and we would be ready to go,” Fischer says. But in the US, there is more money available at universities, a high level of industry cooperation and more infrastructure, for example for keeping pigs under very clean conditions. Pigs have proven to be particularly promising donors. “Pigs are used because they initially show a high degree of compatibility to humans and are actually well suited in terms of anatomical structures,” says transplant surgeon Philipp Felgendreff from the Hannover Medical School, who has “high hopes” for this approach. However, it is still too early to estimate when this procedure could become established and then be made available to the tens of thousands of people who could benefit from it. “Of course, this now depends above all on the studies that are starting in the US,” Felgendreff says. According to the surgeon, people with pig organs have so far survived for a few months, whereas with human organs the probability of survival has long been 10, 15 or even 20 years. “There the gap is still very, very large.” One challenge is to ensure that animal organs are free of microorganisms that could harm humans. It is not easy to assess the risk of infection through transplantation, says Joachim Denner of the Free University of Berlin. This is because viruses can bypass the skin’s protective system and enter the system. There are also viruses that do no harm to healthy people, but do to sick people. Denner recalls that a case was reported of a herpes virus from pigs being transmitted and contributing to the death of the patient. He and numerous other experts are working to reduce the risk of transmission. For example, a vaccine against porcine retroviruses has been developed as a purely precautionary measure. These are integrated into the genome of the pig and cannot be eliminated by breeding under germ-free conditions. As soon as I woke up after the surgery, the cloud of dialysis disappeared. I felt re-energised and revitalised. It was a miracle Tim Andrews after receiving a pig kidney transplant The current focus is on kidneys and hearts, but humans can receive many more animal organs. Research is also being conducted on the transplantation of livers and lungs, of joint cells and islet cells for people with diabetes, as well as heart valves and the transplantation of skin and bone particles, for example after burns. “Almost all organs and tissues from pigs can be used to heal patients,” explains Fischer. But which people are eligible for such a risky procedure – and which ones want it? United Therapeutics would like to include patients in the study who, for medical reasons, are not eligible for a human transplant, as well as those who are more likely to die than to receive a kidney within the next five years. Transplant surgeon Felgendreff also believes that a xenograft should not be given to someone who has a good chance of receiving a human organ. It is also conceivable, for example, that someone with acute liver failure might need a liver quickly. In this case, the pig organ could be used as a temporary solution for a certain period of time. If the upcoming studies go well, xenotransplantation could help patients on the waiting list, says Felgendreff. And it could be “really soon – even if we’re still talking about years”. Tim Andrews, 66, received a pig kidney developed by eGenesis at the end of January. He had previously been dependent on dialysis for two years, like millions of other people worldwide with diseased kidneys. According to the company, the dialysis made him feel constantly tired and unable to pursue his usual activities. He says: “As soon as I woke up after the surgery, the cloud of dialysis disappeared. I felt re-energised and revitalised. It was a miracle.” For people like him, pig kidneys are a “glimmer of hope”. Like what you read? Follow SCMP Lifestyle on Facebook, X and Instagram. You can also sign up for our eNewsletter here.

How pig kidney transplants, as well as hearts, lungs and skin, could save many human lives

.css-1c6uqr6{color:inherit;font-weight:inherit;font-size:inherit;font-family:inherit;line-height:inherit;overflow-wrap:break-word;}The US recently approved clinical trials for pig kidney transplants, opening the door to the potential use of other organs and body parts

The US recently approved clinical trials for pig kidney transplants, opening the door to the potential use of other organs and body parts