HEART OF A PIG FOR HUMAN

Historic US transplant

An American man with terminal heart disease was implanted with a genetically modified pig heart in a first-of-its-kind surgery — and three days later, is doing well, his doctors reported on Monday.

The surgery, performed by a team at the University of Maryland Medicine, is among the first to demonstrate the feasibility of a pig-tohuman heart transplant, a field made possible by new gene-editing tools.

If the surgery continues to prove successful, scientists hope pig organs could help alleviate shortages of those from human donors.

“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 Griffith, who impnated the heart. “We are proceeding cautiously, but we are also optimistic that this first-inthe-world surgery will provide an important new option for patients in the future.”

His last chance

For 57-year-old David Bennett (inset) of Maryland, the transplant was his last option.

“It was either die or do this transplant,” Bennett said a day before his surgery. “I want to live.”

In order to move ahead with the surgery, the university’s team obtained an emergency authorization from the Food and Drug Administration on New Year’s Eve through its compassionate-use program.

“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,” said Dr. Muhammad Mohiuddin, who heads the university’s program on xenotransplantation — transplanting animal organs into humans.

About 110,000 Americans are currently waiting for an organ transplant, and more than 6,000 die each year before getting one, according to organdonor.gov.

Hope for the future

Pigs have long been a tantalizing source of potential transplants because their organs are so similar to those of humans.

Prior efforts at pig-to-human transplants have failed because of genetic differences that caused organ rejection or viruses that posed an infection risk. Scientists have tackled that problem by editing away potentially harmful genes.

In the heart implanted in Bennett, three genes previously linked to organ rejection were “knocked out” of the donor pig, and six human genes linked to immune acceptance were inserted into the pig genome.