Surgeons at the University of Maryland School of Medicine and the University of Maryland Medical Center announced on Monday that they performed the first successful transplant on Friday of a genetically modified pig's heart in a human.
Suffering from end-stage heart disease, David Bennett, 57, had been deemed ineligible for a conventional heart transplant. As a last resort, the team at the University of Maryland Medical Center, where he was admitted, wanted to attempt a porcine heart transplant .
This type of procedure is not normally approved by the United States Food and Drug Administration (FDA), but the federal agency finally authorized the surgery on December 31 under its "expanded access" provision, typically used when other treatments or treatment options are not available.
The patient, bedridden for several months due to multiple procedures, accepted the risks associated with the surgery, which is still experimental. “It was either die or do that transplant. I want to live “, he said in a statement before the operation. "I know it's a shot in the dark, but it's my last choice “.
Pig hearts have long been considered a replacement for human hearts due to their similarities. Some people have already received porcine heart valves as a replacement . On the other hand, transplanting a whole heart had never been attempted . University of Maryland medical system officials were confident, however, that the procedure could save the patient more time.
For this great first, Dr. Bartley P. Griffith, of the Maryland School of Medicine, teamed up with Dr. Muhammad M. Mohuiddin, creator of the Cardiac Xenotransplantation Program. Together they have studied the technique for the past five years. For the procedure, they used a genetically modified heart offered by the Blacksburg, Va.-based regenerative medicine company Revivicorn, as well as a combination of drugs to prevent the immune system from rejecting the new organ.
The pig had evolved with about ten genetic modifications. Four genes have been deactivated, including one that codes for a molecule causing an aggressive rejection response in humans. A growth gene was also inactivated to prevent the pig's heart from continuing to grow after implantation. In addition, six human genes were inserted into the donor pig's genome to make the pig's organ more tolerable to the immune system of the transplant recipient.
For Dr. Bert W. O'Malley, president and CEO of the University of Maryland Medical Center, this surgery is a "historic step forward and monumental ". The procedure could notably help health care providers to address the organ shortage crisis that leaves thousands of people without treatment options each year.
"There simply aren't enough human hearts available to meet the long list of potential recipients “, emphasizes Dr. Bartley P. Griffith. “We are proceeding with caution, but we are also optimistic that this world-first surgery will provide an important new option for patients in the future “.
Alka Chandna, vice president of laboratory investigations at animal rights organization People for the Ethical Treatment of Animals, spoke out against the procedure (a xenotranspoantation), deeming the practice dangerous and unethical . “The risk of transmitting unknown viruses with the animal organ is real and, in times of pandemic, should be enough to end these studies forever “Ms. Chandna said in a statement. “Animals are not tool sheds to be plundered, but complex and intelligent beings. It would be better for them and healthier for humans to leave them alone and research cures using modern science “.
