Two more pig hearts have been successfully transplanted into humans!
On July 12, 2022, American researchers announced that New York University surgeons had successfully transplanted gene-edited pig hearts into two brain-dead patients.
The two surgeries were performed on June 16, 2022 and July 6, 2022 respectively at NYU Langone Tisch Hospital.
It is reported that the two patients were declared brain-dead before the transplant operation, and were on ventilators and undergoing dialysis before, during and after the operation.
The recipient was monitored for 3 days after the transplant. ’s heart function was normal within 72 hours and there was no sign of rejection. This is a major breakthrough in xenogeneic organ transplantation !
In fact, in January 2022, a 57-year-old man in the United States named David Bennett (David Bennett) had received a pig heart transplant, which was the first case in the world! What happened next?
The world's first pig heart transplant patient
David Bennett suffers from end-stage heart disease and is not eligible for human heart transplantation or the use of a cardiac assist device, and is in critical condition. In order to survive, he decided to undergo xenotransplantation.
Bennett during surgery
On January 7, 2022, the operation was performed at the University of Maryland School of Medicine in the United States. It lasted 7 hours and a pig heart that had been edited by multiple genes was successfully transplanted into David Bennett. He also Became the world's first pig heart transplant patient.
After monitoring for several days, there was no rejection reaction , and I could still sit up in bed. In the weeks that followed, David Bennett's "new heart" was functioning well, and Bennett was able to communicate normally with his loved ones.
Bennett after surgery
However, Bennett’s condition worsened about 40 days after the operation. After it became clear that he could not recover, David Bennett gave up active rescue and chose to spend the last part of his life with his family. a couple of hours.
David Bennett finally passed away on March 8, 2022, and this "pig heart" also worked for nearly 2 months. The cause of Bennett's death was not announced at the time.
Until May 4, 2022, "MIT Technology Review" reported that transplant experts said that the pig heart carried a pig virus, which may have caused the patient's condition to worsen.
Although the pig heart transplant failed to save Bennett's life, the researchers said:
This xenotransplantation surgery provided very valuable information. The discovery of pig viruses is not entirely a bad thing, because viral infections can be Preventive, and transplant rejection is the biggest obstacle to animal organ transplantation.
Before the pig heart transplant, in October 2021, American scientists successfully transplanted a pig's kidney into a brain-dead patient with renal insufficiency without any rejection reaction. This is also a major breakthrough in the medical community.
Now two more pig heart transplants have been successfully completed. This feat brings the human transplantation of pig hearts one step closer to success and may bring major changes to future medicine.
There is currently a serious shortage of organ transplants in the world, and donation alone is far from being able to meet the actual demand.
According to statistics from the World Health Organization , less than 10% of the world's demand for organ transplants can be met every year.
In the United States, about 107,000 people wait for organ transplants every year, and about 17 people die every day while waiting for organ transplants.
In our country, more than 1.5 million patients are waiting for organ transplants every year. Due to the shortage of donors, less than 10,000 people can do so.
A genetically modified pig heart is suspended in solution before xenotransplantation.Image source: JOE CARROTTA
Scientists said that carrying out xenogeneic organ transplantation is a world-recognized important way to solve the organ shortage. Internationally, pigs are the first choice animal for human xenogeneic organ transplantation.
Why have pigs become the “savior” of human organ transplantation?
Many people are very confused. Humans are primates. Why pigs instead of close relatives of humans, such as monkeys, baboons or gorillas ? Can any pig be used for organ transplantation?
At first glance, there are indeed many differences between pigs and humans, but they are regarded by scientists as the creatures most likely to save lives and have extremely high medical research value:
- The biological systems of pigs are highly similar to humans.
Veterinary expert Michael Swindell said: "The various systems of pigs have a very high level of anatomy and physiology commonality with humans. Animals that can work in pigs will also have a high chance of working in humans. .”
Scientists have found that many organ systems in pigs are 80%-90% similar to their corresponding systems in humans.
First of all, pig kidneys are about the same size and shape as humans and work in much the same way. Moreover, scientists also found that the healing process of pig skin wounds is very similar to that of human skin.
Secondly, pigs are true omnivores like humans. The physiological characteristics of their digestive activities and liver and other metabolic processes are very similar to humans. For example, pig insulin and human insulin only differ in one amino acid .
- Pigs are easy to reproduce and have low risks.
Pigs are not only low-cost to raise, but also can reproduce quickly and produce many piglets, which can ensure the supply of xenogeneic organ transplants.
If pig organ transplantation is really applied in daily life, humans may have organs that can be transplanted at any time.
At the same time, regarding why organ transplantation from other primates is not used, Professor Dai Yifan, director of the Jiangsu Provincial Key Laboratory of Xenotransplantation and Nanjing Medical University, said;
"Primates are characterized by long generation gaps. Especially for orangutans and baboons, the generation gap is more than 10 years, the reproduction rate is low, and the feeding cost is also high, making it difficult to meet the needs of human organ transplantation."
Experts also emphasized that pigs must not be infected with certain infectious diseases when raising them, otherwise they must not be infected with certain infectious diseases. It can pose a fatal threat to people receiving organ transplants.
Precisely because some primates are "close relatives" of humans, viruses that exist in monkey tissues are more likely to infect humans, and the risk is extremely high. For example, the HIV virus (AIDS) originally came from apes, but after changing its form, it is quite lethal to humans.
Therefore, not all pigs can be used for organ transplantation. Organ transplantation between different species will produce stronger rejection reactions.
The pigs actually used in the surgery have been genetically modified many times, and 6 human genes will also be implanted to enhance the tolerance of the pig organs to the human immune system.
However, can xenogeneic organ transplantation, a technology with huge challenges, really enter human life in the future? Perhaps more extensive inquiry is needed.
Because in addition to the technical aspects, there are also many ethical issues involved...
