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The heart transplant from a genetically modified pig was initially considered a success and represented new hope for Americans requiring transplants.
The first person to have a failing heart replaced with one from a genetically altered pig has died two months after the transplant surgery.
A man with severe heart disease, David Bennett Sr., aged 57 years, had agreed to receive the experimental pig’s heart after being rejected from several waiting lists to receive a human heart.
Initially, the transplant was considered successful and is still regarded as a significant step forward for transplants. The heart was not immediately rejected and functioned for over a month, a critical milestone for transplant patients.
There were no clear answers to whether Bennett’s body had rejected the pig’s heart and hospital officials noted “no obvious cause identified at the time of his death" according to a New York Times report.
Officials additionally stated they could not comment further on the cause of death, because a thorough examination had not yet been performed by the man’s physician. There are plans to publish the results in a peer-reviewed medical journal.
The surgeon who performed the transplant said the hospital was “devastated” by the loss of Bennett.
“He proved to be a brave and noble patient who fought all the way to the end,” said Bartley Griffith, MD. “Mr. Bennett became known by millions of people around the world for his courage and steadfast will to live.”
A severe shortage of organs has led to a dozen or more patients on waiting lists dying each day. Approximately 3,800 patients in the US received human donor hearts last year, but the demand remains high.
The process, known as xenotransplantation, may represent new hope for patients with failing kidneys, hearts, and other organs, which are facing an acute shortage of donated organs. This heart transplant was one of a few pioneering procedures recently in which organs from genetically altered pigs were used to replace organs in humans.
For this procedure, the heart came from a genetically altered pig provided by regenerative medicine company Revivicor. The pig was noted to have carried 10 genetic modifications, with 4 genes inactivated, including one that encodes a molecule linked to an aggressive human rejection response.
Additionally, a gene was inactivated to prevent the pig heart from continuing to grow after it was implanted and 6 human genes were inserted into the pig to make the pig’s organs more tolerable to the human immune system.
The US Food and Drug Administration (FDA) granted emergency authorization for the experimental surgery on New Year’s Eve and the surgery took place a week later. Reports say the transplanted heart performed well, with no signs of rejection for several weeks.
However, Bennet was not discharged and hospital officials noted his condition began to deteriorate days before his death.
His son, David Bennett Jr, put out a statement thanking the hospital and staff for their exhaustive efforts during the process.
“We hope this story can be the beginning of hope and not the end,” Bennett said. “We also hope that what was learned from his surgery will benefit future patients and hopefully one day, end the organ shortage that costs so many lives each year.”