In a breakthrough operation that may offer hope to thousands of patients with failing organs worldwide, a US medical team has successfully implanted the heart of a genetically altered pig. The transplant, a ground breaking first of its kind, was received in Baltimore on Friday by 57-year-old David Bennett Sr. who had a life-threatening heart disease.
According to surgeons at the University of Maryland Medical Center, the eight-hour operation was a huge success and the receiver is doing well days later.
“It creates the pulse, it creates the pressure, it is his heart. It’s working and it looks normal. We are thrilled but we don’t know what tomorrow will bring us. This has never been done before,” said Dr. Bartley Griffith, the director of the cardiac transplant program at the medical center, who performed the operation.
The new feat has many advantages coming with it. In the main, it looks like it is the panacea for the shortage of transplant organs even though there is organ rejection challenge currently being sorted out with recipients being placed on a life-long damaging anti-rejection drugs. The good news is that researchers hope to overcome the challenge by tricking the immune system instead.
Indeed, there is an acute shortage of organs in the US alone. Though 41,354 Americans received a transplanted organ, with more than half of them receiving kidneys, about 3,817 received human donor hearts over the same period, a figure that is more than ever before. Sadly, about a dozen people on the waiting lists die each day.
That accounts for why scientists are working feverishly to develop pigs whose organs would not be rejected by the human body, with research accelerated in the past decade by new gene editing and cloning technologies.
Remarkably, the breakthrough heart transplant is coming barely months after New York surgeons successfully attached the kidney of a genetically engineered pig to a brain-dead person. The belief in research circles is that procedures like this will be the beginning of a new medical era where, in the future, replacement organs will no longer be in short supply.
“This is a watershed event. Doors are starting to open that will lead, I believe, to major changes in how we treat organ failure,” said Dr. David Klassen, the chief medical officer of the United Network for Organ Sharing and a transplant physician.
The experimental treatment for Mr. Bennett was a last resort gamble because he was certain to die without a new heart, having exhausted other treatment option. He was, according to family members and doctors, also too sick to qualify for a human donor heart and was on a heart-lung bypass machine before the operation.
At the moment, Mr Bennett’s new heart is functioning and already doing most of the work prompting the doctors to conclude that he could be taken off the machine on Tuesday. Albeit, he is being closely monitored for signs that his body is rejecting the new organ even though the first 48 critical hours went by without incident.
“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,” Mr. Bennett reportedly said before the surgery.
Records indicate that Xenotransplantation, the process of grafting or transplanting organs or tissues from animals to humans, is not new. In the ’60s, surgeons transplanted chimpanzee kidneys into some human patients. It failed largely because the longest recipient lived only nine months.
In 1983, surgeon transplanted a baboon’s heart into an infant known. However, she died 20 days after the transplant. There is however, a consensus that pigs offer better survival chances over primates for sundry reasons. Their organs are easily procured as they are not only easy to raise, they also achieve adult human size in just six months.
Routinely, pig heart valves have been transplanted into humans and some diabetic patients are known to have received porcine pancreas cells. Yet, pig skin is also known to have been used as a temporary graft for burn patients.
Prior to the trial on human, pig hearts have successfully been transplanted into primates, including baboons. The transplant was carried out Dr. Muhammad Mohiuddin, a professor of surgery at University of Maryland School of Medicine. As Scientific Director, he established the Cardiac Xenotransplantation program with Dr. Griffith. Until recently, their use in humans precluded safety concerns and fear of setting off a dangerous immune response that can be life-threatening.
Two newer technologies are involved. They include gene editing and cloning both of which have yielded genetically altered pig organs that are less likely to be rejected by humans. Pig hearts have been transplanted successfully into baboons by Dr. Muhammad Mohiuddin, a professor of surgery at University of Maryland School of Medicine who established the cardiac xenotransplantation program with Dr. Griffith and is its scientific director. But safety concerns and fear of setting off a dangerous immune response that can be life-threatening precluded their use in humans until recently.
According to Dr. Jay Fishman, Associate Director, Transplantation Center, Massachusetts General Hospital, using pig organs provides the ability to perform genetic manipulations. He is of the opinion that the it also provides the time to carry out better screening for infectious diseases, and the possibility of a new organ at the time that the patient needs it.
“There are challenges for sure, but also opportunities,” he said.