With an acute shortage of hearts for transplants, science comes up with new options

According to the United Network for Organ Sharing, in the past year alone, 41,354 Americans received a transplanted organ. Although most of those organs were kidneys, heart transplantations were not far behind. Some 3,817 Americans received human donor hearts in 2021 – more than in any prior year.

The thing is, it’s very difficult to find near-perfect matches for those in need of a heart transplant. It can also be tough and time-consuming for patients to get on the heart transplant registry. You must meet hundreds of standards to qualify, most related to being healthy enough to survive the multi-hour surgery and prolonged recovery.

To answer this growing need for healthy, available donor hearts, research scientists have been working hard to develop new organ sources. One source that has shown a lot of promise is a pig heart. Close in size and shape to the human heart, it can be genetically modified through gene editing and cloning in labs so that it will not be rejected by the human body.

Still, it was considered groundbreaking when a 57-year-old man with life-threatening heart disease (unable to qualify for the donor transplant registry) received a transplanted heart from a genetically modified pig earlier this month — the first successful transplant of a pig’s heart into a human being.

The recipient of the transplanted heart opted for the experimental treatment because he had exhausted other heart treatments and was too sick to qualify for a human donor heart. He knew the risks, but wanted to live, so he took the chance. Doctors and family members confirm he would have died without the new transplant.

As you might expect The Food and Drug Administration was also involved in in the groundwork, working intensely with researchers and finally giving the transplant surgeons an emergency authorization for the operation on New Year’s Eve.

After an eight-hour operation, the new heart is fully functioning so the 57-year old was taken off the heart-lung machine less than a week after surgery. Although his long-term prognosis is uncertain, he is being closely monitored for infections, including porcine retrovirus, a pig virus that can be transmitted to humans, although the risk is low.

“This is a watershed event,” said Dr. David Klassen, the chief medical officer of the United Network for Organ Sharing and a transplant physician. “Doors are starting to open that will lead, I believe, to major changes in how we treat organ failure.”

“(The pig heart) creates the pulse, it creates the pressure, it is his heart,” said Dr. Bartley Griffith, the director of the cardiac transplant program at the medical center, who performed the operation. “It’s working and it looks normal. We are thrilled.”

The heart transplanted into the patient came from a genetically altered pig provided by Revivicor, a regenerative medicine company based in Blacksburg, Va. The pig received ten genetic modifications; four genes were inactivated to prevent human rejection response; and another six human genes were inserted into the genome of the porcine donor. A growth gene was also inactivated to prevent the pig’s heart from continuing to grow after it was implanted. Each of these modifications were designed to make pig heart more tolerable to its intended human immune system.

According to The New York Times story covering the event, “Researchers hope procedures like this will usher in a new era in medicine in the future when replacement organs are no longer in short supply for the more than half a million Americans who are waiting for kidneys and other organs.”

This new procedure might well offer new hope to hundreds of thousands of patients with failing hearts, who are too sick to qualify for the national registry. Given the acute shortage of healthy, transplantable hearts, dozens of people on the national donor registry die every day.

Although MediGO was not involved in this groundbreaking transplant, we are fiercely proud to be a part of the transplant system in the United States. As transplants continue to evolve, we realize there is more need than ever for enhanced transparency and communication for more healthy outcomes to save more lives.