BY ALICE PARK
GOOD QUESTION
ON MARCH 16, A TRANSPLANT-SURGERY TEAM AT MASSA-chusetts General Hospital successfully transplanted a modified pig kidney into a human: 62-year-old Richard Slayman. The groundbreaking, four-hour surgery was the culmination of years of work transplanting kidneys from a specially bred group of pigs—genetically modified to more closely resemble those of humans—into primates. Encouraged by those results, the team at Mass General Brigham was confident it was time to test the pig organs in the first patient.
Slayman, a manager at the Massachusetts department of transportation, had received a human kidney transplant five years ago, but as is often the case with kidney disease, the organ began to fail and he continued to need dialysis. His health progressively worsened. “At one point, he literally said, I just cannot go on like this,” said Dr. Winfred Williams, Slayman’s physician and associate chair of nephrology at Mass General, during a briefing.
Dr. Tatsuo Kawai, director of the hospital’s Legorreta Center for Clinical Transplant Tolerance, who had performed the human transplant five years ago, also performed the pig-kidney surgery. As more than a dozen people watched, Kawai carefully connected the pig kidney to Slayman’s circulatory system—not an easy task, given the patient’s history of diabetes and hypertension, which had weakened his blood vessels. “The size of the pig kidney was exactly the same as the human kidney,” he said. “Upon restoration of blood flow into the kidney, the kidney pinked up immediately and started to make urine. When we saw the first urine output, everyone in the operating room burst into applause. It was truly the most beautiful kidney I have ever seen.”
The kidney came from a special group of pigs bred to produce human-like kidneys. Biotech company eGenesis worked closely with the hospital to produce them, using genetic innovations developed over recent decades. The pigs’ cells were treated with the gene-editing technology CRISPR, which allows scientists to make very precise genetic changes in cells. These cells were then used to create pig clones so the pigs would have identical and consistent genetic changes. Their kidneys were then transplanted first into primates, and finally into Slayma
