Pig organ transplants inch closer with testing

New York researchers transplanted pig hearts into two brain-dead people over the last month, the latest in a string of developments in the long quest to one day save human lives with animal organs.

The experiments announced Tuesday come after a historic but failed attempt earlier this year to use a pig's heart to save a dying Maryland man — sort of a rehearsal before scientists try again in the living.

Among the lessons: Practice with the deceased is important.

"We learned so much from the first one that the second one is much better," said Dr. Nader Moazami, who led the operations at NYU Langone Health. "You stand there in awe" when the pig heart starts to beat in a human body.

This time around, Moazami's team mimicked how heart transplants routinely are done. Once last month and once last week, researchers traveled to a facility housing genetically modified pigs, removed the needed hearts, put them on ice and flew them hundreds of miles back to New York.

They used special new methods to check for any worrisome animal viruses before sewing the heart into the chest of each deceased recipient — a Vietnam veteran from Pennsylvania with a long history of heart disease and a New York woman who'd benefited from a transplant earlier in life.

Then came three days of more intense testing than living patients could tolerate — including frequent biopsies of the organ — before doctors disconnected life support.

Already the Food and Drug Administration is considering whether to allow a small number of Americans who need a new organ to volunteer for rigorous studies of either pig hearts or kidneys. NYU Langone is among three transplant centers planning trials — and has a meeting planned with the FDA in August to discuss requirements.

Testing in the deceased could help fine-tune how the first trials in the living are designed, said Dr. David Klassen of the United Network for Organ Sharing, which oversees the nation's transplant system.

"They serve as an important sort of stepping stone," said Klassen, who wonders if researchers next might consider tracking the organs for a week or so in a donated body rather than just three days.

Animal-to-human transplants, what scientists call xenotransplantation, have been tried for decades without success, as people's immune systems almost instantly attacked the foreign tissue. Now, pigs are being genetically modified so their organs are more human-like — increasing hope that they might one day help fill a shortage of donated organs. More than 100,000 people are on the national waiting list for a transplant, most of them kidney patients, and thousands die every year before their turn comes.