For the first time, a team of surgeons in the United States has succeeded in transplanting into a man with serious heart disease a heart from a pig that has been genetically modified to make it compatible with the human body.
This pioneering operation lasted eight hours and was successfully performed last Friday by a team of surgeons from the University of Maryland Medical Center, in the United States. The recipient is a 57-year-old man, David Bennett, who suffered from life-threatening heart disease.
It is the first successful transplant from a pig heart to a human being and, according to experts, this innovative procedure offers new hope for the hundreds of thousands of people around the world who are on the waiting list to be able to replace your damaged heart.
Three days after the operation, the transplanted organ continues to function and has already passed the first critical stage: the first 48 hours.
In fact, the medical team hopes to be able to remove in a few hours the machine that helps the patient to adapt to his new heart and that detects any sign of rejection or some type of infection, for example by a virus of porcine origin, which it can be serious for the human recipient.
“It creates the pulse, it creates the pressure, it is your heart,” Dr. Bartley Griffith, who has performed this historic operation, told the New York Times. He adds: “It’s working and it seems normal. We’re excited, but we don’t know what tomorrow will bring. This has never been done before.”
For several decades, scientists around the world have been working to develop pigs whose organs are not rejected by the human body, but this type of research has accelerated in recent years thanks to the use of modern gene editing techniques.
A couple of months ago, another team of doctors in New York successfully transplanted a kidney from a genetically modified pig into a brain-dead person.
On this occasion, Dr. Bennett’s team decided to go for an experimental treatment, because the patient would have died without a new heart and was already too ill to be able to access a heart from a human donor.
Transplants to humans of animal organs are called “xenotransplantation” and already have a long history.
In the 1960s, the first chimpanzee kidneys were transplanted into some human patients, but the maximum life span of a recipient was nine months. In 1983, a baboon heart was transplanted into a baby, but the baby died 20 days later.
Advantages over primates
Pigs offer advantages over primates for organ procurement, because they are easier to raise and reach adult human size in just six months.
On this occasion, David Bennett’s transplanted heart came from a genetically modified pig by scientists from Revivicor, a regenerative medicine company based in the US state of Virginia.
The pig had 10 genetic modifications, and four genes were turned off, including one that encodes a molecule that elicits an aggressive human rejection response and another to prevent the pig’s heart from continuing to grow after implantation.
Additionally, six human genes were inserted into the donor pig genome, modifications designed to make pig organs more tolerable to the human immune system.
George Holan is chief editor at Plainsmen Post and has articles published in many notable publications in the last decade.