On January 7, local time, scientists and clinicians at the University of Maryland School of Medicine successfully transplanted a pig's heart into an adult patient with end-stage heart disease.
On the third day after the operation, the 57-year-old man who received the transplant is currently in good condition, and the pig heart in his chest cavity is still beating "sonorously and powerfully" and has not yet appeared rejection.
This is the first time in the history of world medicine that a pig heart has been successfully transplanted into the human body, which is "simply a miracle".
"Die or receive a pig heart transplant"
"I want to live! Receiving a pig heart transplant was my last resort. Dave Bennett said the day before undergoing surgery.
Last October, Dave Bennett, 57, developed severe chest pain that made it difficult to climb three steps, and doctors diagnosed him with "end-stage heart disease." 6 weeks ago, due to severe arrhythmias, Dave could only maintain life by connecting extracorporeal membrane oxygenation (ECMO) machines.
Dave with family in 2019
Dave has been telling the head of surgery, Dr. Bartley P. Griffith, that "I want to have a human heart." However, the reality is harsh. Dave's arrhythmias are difficult to control, and there is a serious shortage of donated human organs for transplantation, he does not receive the conditions of the same organ transplant or artificial heart pump, and the patient's life is in danger.
Desperate, Dave underwent a swine heart transplant. This is the first time in human history that a pig heart has been transplanted into the human body, and this experimental operation is an adventure for both Dave and the surgeon, and the process is full of countless challenges, and no one can predict the outcome. "Either die or receive a pig heart transplant." To survive, Dave had no choice.
Surgical procedure Source: Youtube video
"Whoever succeeds is right, whoever fails is wrong, and there is no need for much explanation during surgery." To save patients' lives, the FDA granted emergency authorization for surgery on New Year's Eve.
The transplant takes place on January 7 from 8:30 a.m. to around 5:30 p.m. During the 9-hour operation, doctors replaced Dave's original heart with a 1-year-old, 240-pound piglet heart. And this little piglet is the regenerative medicine company Revivicor specifically for xenotransplantation gene editing and breeding.
Dave with attending physician Bartley
The surgery was a success. 3 days after surgery, Dave is already able to breathe on his own without the assistance of a ventilator. Although he is still using the ECMO machine to help pump blood throughout his body, the auxiliary effect of the machine has been reduced to half, and the doctor plans to let him gradually "wean". Over the next few weeks, doctors will continue to examine Dave's condition to determine the function of the "new heart."
"This is a breakthrough surgery that will help us end the 'organ shortage crisis' in the future." Attending Physician Bartley said, "We will continue to monitor the patient's condition and proceed with caution." But we are optimistic that this world-first xeno-heart transplant will be a path that more patients will choose in the future. ”
Photo of Dr. Bartley P. Griffith
Why "Pig"?
The so-called xenotransplantation refers to the fact that organ transplantation occurs between different species. However, due to the different species, xenotransplantation can easily trigger a strong immune response, triggering the rejection of the organ, resulting in the death of the transplant recipient.
In 1984, scientists tried xenotransplantation for the first time, when they tried to transplant a baboon's heart to a baby with a congenital heart disease. Unfortunately, due to the mismatch between the baboon and the baby's blood type, the immune system was rejected, and the child died less than a month after the operation, which is also the blockbuster Baby Fae case.
After a series of failed attempts at baboons, goats, rabbits, dogs, etc., scientists set their sights on pigs. Many organs in pigs are almost the same size as the size of human organs, such as kidneys and hearts, and the two may have similar functional effects.
Image source: Revivicor official website
Direct transplantation obviously doesn't work. In addition to immune rejection, pig organs also carry a variety of viruses. Because pigs carry many viruses themselves, their organs also carry viruses. If the organs of pigs are transplanted, the virus should be removed from the beginning. How does this process work?
So, researchers thought of gene compilation technology. The researchers used CRISPR/Cas9 technology to make the organs in pigs no longer carry the virus and reduce the immune response that the organs may produce. However, there are about 100,000 genes in pigs, and it sounds like a fantasy to try to transplant pig hearts into the human body by compiling 10 of them.
Image source: Nature Biotechnology
But the scientists managed to do just that. The donor pigs in this operation had undergone 10 specific genetic modifications before birth, including knocking out 3 genes that "may cause immune rejection", inserting 6 human genes that "prevent blood from clotting in the heart", and knocking out 1 "overgrowth" gene.
In order to be able to transplant smoothly, the research team will place the pig heart in a special box after removing it, and this box will continuously perfuse the heart with nutrients and hormones to keep the pig heart functioning well. At the same time, patients also need to take immunosuppressive drugs regularly to prevent the body from rejecting foreign organs, which also plays a vital role in the long-term survival of transplanted organs.
Heart Storage Box Source: Youtube video
David Ayares, executive vice president and chief scientific officer at Revivicor, said, "This is one of the most exciting things in my more than 20-year career. This pig heart xenotransplantation is a pioneering event, and the success of this operation has contributed to the future use of xenotransplanted organs in humans. ”
What constitutes a "successful transplant"?
Similarly, the experimental surgery of swine heart transplantation has only ended for 3 days, and the patient is currently in good condition, but still needs to rely on ECMO assistance. Can such an outcome be judged as "success"?
Pig Hearts Waiting to Be Transplanted Image Source: Youtube video
Commenting on the operation, the US media said, "Since no one has relied on animal organs to survive before, any survival can be regarded as success." "This experimental surgery has given scientists the true picture of humans to further study allogeneic transplantation.
Professor Tector of the University of Miami said, "I will not operate on the patient until I have determined that the patient has a survival period of at least one year. Since the allogeneic transplantation has been chosen, it proves that researchers have strong confidence that patients can survive for a long time. ”
Reichar, CEO of XTransplant, expressed his hope that "Dave could live forever with his new heart." Why only one year of success, not three or five years? We'll see. ”
It can be said that this surgery is a big step in the field of xenotransplantation. However, at this stage, it is still too early to determine the effectiveness of this pig heart transplant.
Was it Dave who did not die of heart failure to prove the possibility of xenotransplantation, or was his life extended by three or five years counted as a successful transplant? Leave your opinion in the comments section~
bibliography:
1.https://www.medschool.umaryland.edu/news/2022/University-of-Maryland-School-of-Medicine-Faculty-Scientists-and-Clinicians-Perform-Historic-First-Successful-Transplant-of-Porcine-Heart-into-Adult-Human-with-End-Stage-Heart-Disease.html
2.https://www.usatoday.com/story/news/health/2022/01/10/human-pig-heart-transplant/9152951002/
3.https://medicalxpress.com/news/2022-01-1st-surgeons-transplant-pig-heart.html
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