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Today is the 559th issue that Jian Ge said to accompany you
Recently, the surgical team of the University of Maryland School of Medicine in the United States successfully transplanted a gene-edited pig heart into the human body, which is the world's first successful human surgery to receive pig heart transplantation, and it is also the world's first transgenic xeno heart transplant. As soon as the news came out, it caused widespread discussion.
Doctors performed a swine heart transplant for Bennett
The world's first xeno heart transplant
The transplant was performed by a 57-year-old man named David Bennett, who suffered from severe chest pain last October at the University of Maryland Medical Center but did not improve, and his condition was in the terminal stages of heart failure, and he had to rely on machines to survive. Moreover, he was also accompanied by a severe arrhythmia, unable to use an artificial heart, and unable to wait for a heart donation, so receiving a xenograft became Bennett's only hope for survival.
Organ transplantation, used to treat end-stage organ failure and save thousands of dying patients, has been universally accepted by society. At present, about 1.5 million patients in mainland China need organ transplantation every year, but there are only 11,000 organ transplants every year, of which only about 500 are heart transplants, and more patients die because they do not receive effective treatment.
If animals could act as organ donors, it would save many lives.
The use of pigs to achieve heart transplantation, rather than primates, is due to the fact that the large blood vessels of the heart of pigs are highly matched with human organs in terms of anatomy and physiological indicators, and pigs are very fertile and can provide a large number of organs.
Difficulties of xenotransplantation
In fact, the success rate of heart transplant surgery in the clinic is very high, and the one-year survival rate of heart transplant surgery in mainland China in the past three years has exceeded 92.5%[1]. Therefore, the biggest difficulty of xenotransplantation across species lies in immune rejection.
The first thing to overcome is hyperacute rejection. The human body is stocked with antibodies against foreign bodies, including anti-pig antibodies, which bind to antigens on pig cells within minutes to hours after the pig heart enters the human body, and after a series of reactions, the pig heart loses its function, resulting in transplant failure.
Most groundbreakingly, this heart transplant applied gene editing technology to solve the problem of ultra-acute rejection. The researchers made 10 genetic modifications to the donor pig, knocking out three genes that quickly cause organ rejection and one gene that regulates growth; and adding six genes that improved the pig's heart's tolerance to the human immune system.
According to relevant reports, Bennett currently has no ultra-acute rejection reaction, but he still needs to take anti-rejection drugs for life and needs months or even years to observe whether chronic rejection occurs.
A groundbreaking small step
The final result of this cross-species heart transplant is still unknown. But, whatever the outcome, this surgery is a groundbreaking attempt and an important milestone in the history of human organ replacement therapy, and it will be like a small step taken by Armstrong, a big step in human organ replacement therapy.
Xenotransplantation undoubtedly brings hope for many critically ill patients in organ failure, and may also cause doubts about the identity of patients themselves and society. While this groundbreaking treatment may bring ethical dilemmas, we can be more tolerant and less playful about patients receiving xenotransplantations or for species that provide organs, while saving lives.
Let us all hope that with the advancement of technology and the improvement of ethical regulations, more patients will benefit from xenotransplantation and enter a healthier state of life.
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"On the Heart" - Medicine, Health and Lifestyle of the Heart
Works by Professor Liu Jian