The experiments, reported on Thursday in the journal Science, may make it possible one day to transplant livers, hearts and other organs from pigs into humans, a hope that experts had all but given up.
If pig organs were shown to be safe and effective, "they could be a real game changer," said Dr. David Klassen, chief medical officer at the United Network for Organ Sharing, a private, nonprofit organization that manages the nation's transplant system.
There were 33,600 organ transplants last year, and 116,800 patients on waiting lists, according to Dr. Klassen, who was not involved in the new study. "There's a big gap between organ supply and organ demand," he said.
Dr. George Church, a geneticist at Harvard who led the experiments, said the first pig-to-human transplants could occur within two years.