Recently, the University of Maryland School of Medicine in the United States said that a 57-year-old heart patient successfully underwent a transgenic pig heart transplant, 3 days after the operation, and the current patient's condition is very good.
I believe you must have a lot of problems!
Can organ transplantation of pigs already be done to humans? Are there any success stories? Will transplantation make us live longer?
Why GMO Pigs? What does genetic modification have to do with it?
First of all, let everyone know that this is a transplant in transplant surgery. Everyone knows that transplants are best twins, then the same species, at least human and human. The worst is between humans and animals, between xenomorphs.
In 1906, humans tried allogeneic transplantation for the first time. Doctors boldly transplanted the kidneys of pigs and goats into two patients. Unfortunately, because the rejection response was not understood at the time, the patient died quickly. There is no doubt that this is the "dead horse as a living horse doctor" method adopted by doctors when they are helpless.
In 1936, Soviet doctors transplanted the kidney of a patient who died of encephalitis to a 26-year-old patient with acute renal failure who was mercury poisoned. This was the world's first successful human-to-human kidney transplant, but the patient survived for 6 days.
In December 1952, a 16-year-old teenager in Paris, France, whose right kidney was completely damaged by an accidental injury, required immediate removal of his right kidney, and the doctor unexpectedly found that he was born without a left kidney. His mother repeatedly begged doctors to cut off her healthy left kidney and transplant it into her son so that the child could hope to survive. The operation was successful, but there was still a severe rejection reaction, and this time the patient survived for 22 days.
For 6 days and 22 days, why does a mother give her child's kidneys 3 times longer than a stranger's kidneys?
Just two years later, Murray, the father of modern transplantology, waited for a perfect opportunity for surgery. That's right, it's a transplant from a twin brother. The brothers were both soldiers, and when they were ready to resume their lives after serving, the younger brother was diagnosed with chronic diffuse glomerulonephritis, which was life-threatening.
The older brother demanded that a kidney be donated to his younger brother. On December 23, 1954, the twin brothers underwent a transplant. The operation was very successful, 7 days, 1 month, 2 months passed, and the patient did not have any problems after the operation. In order to verify the matching of the twins, the older brother and younger brother underwent another experimental skin graft, which was also very successful and did not reject. The younger brother lived for 8 years after surgery.
So why do pig transplants? The answer is obvious, there are not enough donors. According to incomplete statistics, about 2 million people in the world need organ transplants every year, but the World Health Organization data shows that the global average organ supply-demand ratio is 1:20 to 1:30.
So the transplant chose the pig. What are the benefits of pigs? The organs of pigs are more convenient because pigs can be raised within 6 months, and their organs reach the size of adults. Pig heart valves were routinely transplanted into the human body, and diabetics received pancreatic cells from pigs, and burn patients transplanted pig skin.
Because the cornea itself does not contain blood vessels, there is no antigen, antibody situation, the heart valve of the pig is mainly a mechanical structure, there is no blood supply and no need to eat anti-rejection drugs.
But the heart is not good yet, so the problem is still to improve the pig.
So this transplant is to knock out the 4 genes in the pig, including the attack of the cells on the pig's heart on the human body, and also include the pig's heart will always grow and control him to grow. At the same time, 6 genes were modified to connect human genes to enhance the tolerance of the pig's immune organs to the human body. Let our immune system not kill him. The term for this profession is that both graft-versus-host and host-protest plant rejection are reduced.
The significance of this modification is great, and more genes can be tried in the future, and it seems that pigs may be used to raise a human organ.
But what is the problem at the moment?
A paper published in the journal Xenotransplantation in 2020 presents 4 recent developments in the last 5 years:
More and more genetic changes can be made in pigs
With the introduction of new immunosuppressants, drugs can fight rejection
There is a better understanding of the inflammatory response after swine xenotransplantation, especially the effect of swine endogenous retroviruses on humans.
4. Finally, the experience of using pig organ or cell transplantation to manage non-human primates is added, and slowly know where to start if there is a problem with transplantation.
But there are also many problems, first of all, mainly for terminal patients. For example, the life expectancy is only 1-2 years, and the feeling of a dead horse as a living horse doctor. The current patient does not survive enough to survive a long-term immune rejection response.
The second is the ethical problem, this genetic technology is very good, now it can be used to treat diseases, but also can be used to knock out the genes of pigs, but the last layer of window paper can not be broken. The current requirement is that the genetic changes of the fertilized egg must not be made, otherwise it will be like the gene-edited fetal incident before SUSTech.
Although there is an idiom in China called "human face beast heart", in the face of the highest rights and interests of life, we should respect the development of technology, especially at present, the heart valves, skin, and islet cells of pigs have been relatively mature.
If the scientific and technological tree of medicine is on this branch, or out of the breakthrough of human ethics, it may not be long before the 200 patients who are waiting for transplantation every year will be loaded with animal organs and become "half-orcs". If that day came, would you choose to put pig organs on it and prolong your life?