First Successful Porcine Heart Transplant in Human - A monumental Milestone in Transplant History
Surgeons with genetically modified porcine heart (Photo Credit: University of Maryland School of Medicine)
Xenotransplantation was first attempted in the 1980s but was largely abandoned after the renowned case of Stephanie Fae Beauclair (known as Baby Fae) at the University of Loma Linda, California. An infant born with a fatal heart disease underwent a baboon heart transplant and died within a month of surgery due to immune system rejection of the foreign heart. However, pig heart valves have been successfully used to replace human valves for many years.
Recently, surgeons at the University of Maryland Medicine, performed the first-ever xenotransplantation using a genetically engineered porcine heart into a man with end-stage heart disease. "This was a breakthrough surgery and brings us one step closer to solving the organ shortage crisis. There are simply not enough donor human hearts available to meet the long list of potential recipients," said Dr Bartley P. Griffith, MD who surgically transplanted the pig heart into the patient.
Xenotransplantation can save thousands of lives, but it carries many inherent risks, including the possibility of triggering a dangerous immune response. These reactions can cause immediate organ rejection, which can have fatal consequences for the patient.
The U.S. Food and Drug Administration granted emergency authorization for the surgery on New Year's Eve through its expanded access (compassionate use) provision. The authorization to proceed was granted in the hope of saving the patient's life.
Patient History:
Mr Bennett is 57 years old male patient hospitalized for more than six weeks with life-threatening arrhythmia and survived with a cardiopulmonary bypass device called Extracorporeal Membrane Oxygenation (ECMO). In addition to not being on the transplant list, he was considered unsuitable for an artificial heart pump due to his arrhythmia.
"It was either die or do this transplant. I want to live. I know it's a shot in the dark, but it's my last choice," said Mr David Bennett, the patient, a day before the surgery was conducted.
The Historic Procedure:
Revivicor, a regenerative medicine company based in Blacksburg, has developed genetically engineered pigs for the University of Maryland School of Medicine (UMSOM) xenotransplantation laboratory.
Three genes responsible for rapid antibody-mediated rejection of pig organs by humans were "knocked out" in the donor pig. Six human genes responsible for the immune acceptance of the pig heart were inserted into the genome. Lastly, one additional gene in the pig was knocked out to prevent excessive growth of the pig heart tissue, which totalled 10 unique gene edits made in the donor pig.
Before the procedure, Mr Bennett was fully informed of the procedure's risks, and that the procedure was experimental with unknown risks and benefits.
On the morning of the transplantation, a surgical team led by Dr Griffith and Dr Mohiuddin removed the pig's heart and placed it in the perfusion device XVIVO Heart box that protects the heart until surgery. Surgeons further used a novel drug manufactured by Kiniksa Pharmaceuticals along with traditional anti-rejection drugs. He is being carefully monitored over the next days and weeks to determine whether the transplant provides lifesaving benefits.
Dr Maya Guglin (Indiana University Health, Indianapolis), chair of the American College of Cardiology Heart Failure and Transplant Council, said in an interview "This surgery is momentous. However, it remains too early to call it a complete success because the point of transplant is to have the patient survive for several "meaningful" years and not mere days, but I'm hopeful."
Dr Mohiuddin said, "This is the culmination of years of highly complicated research to hone this technique in animals with survival times that have reached beyond nine months. The FDA used our data and data on the experimental pig to authorize the transplant in an end-stage heart disease patient who had no other treatment options".
He further added, "The successful procedure provided valuable information to help the medical community improve this potentially life-saving method in future patients."
For further information:
University of Maryland School of Medicine. 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. Published: January 10, 2022.
