A US medical team has succeeded in temporarily attaching a pig’s kidney to a person, a transplant breakthrough hailed as a “potential miracle” by the surgeon who led the procedure.

The surgery, carried out on September 25, involved a genetically modified donor animal and a brain dead patient on a ventilator whose family had given permission for the two-day experiment, for the sake of advancing science.

“It did what it’s supposed to do, which is remove waste and make urine,” Robert Montgomery, director of the transplant institute at New York University (NYU) Langone, told AFP in an interview.

Critically, the organ was able to reduce the level of the molecule creatinine, a key indicator of kidney health that was elevated in the patient prior to the transplant.

Montgomery carried out the surgery with several colleagues over the course of around two hours.
They joined the kidney to blood vessels on the top of one of the patient’s legs, so that they could observe it and take biopsy samples.

The patient had wanted to be an organ donor and their family was initially disappointed when told their loved one’s organs were not suitable, said Montgomery.

But “they felt a sense of relief that this was another opportunity for donation,” he said. The patient was taken off the ventilator and passed away following the 54-hour test.

 ‘Important intermediate step’ 
Earlier research has shown that kidneys from pigs are viable in nonhuman primates for up to a year, but this was the first time it had been attempted with a human patient.

The donor pig belonged to a herd that had undergone a genetic editing procedure to knock out a gene that produces a particular sugar, which would otherwise have triggered a strong immune response and led to organ rejection.

The editing was performed by biotech firm Revivicor, a subsidiary of United Therapeutics.

“It is still a question what would happen three weeks from now, three months, three years,” said Montgomery.
“The only way we’re really going to be able to answer that is to move this into a living human trial. But I think this is a really important intermediate step, which tells us that at least initially, things are probably going to be okay.”

He plans to submit the findings to a scientific journal in the next month, and says a clinical trial could take place in around a year or two.

The news was welcomed cautiously by outside experts, who nonetheless said they would like to see the peer-reviewed data before drawing firm conclusions.

“This news is a significant scientific achievement in the xenotransplantation field,” Hynek Mergental, a surgeon at the University of Birmingham in Britain said in a statement.

If confirmed, “it would be a major step forward in the organ transplant field that might solve the critical shortage of donor organs,” he added.