Ellen Phiddian
Researchers have successfully transplanted a genetically modified kidney from a pig into a brain-dead human.
The kidney operated normally for a week.
The US research team completed the so-called “xenotransplant” after receiving permission from the family of the brain-dead patient with chronic kidney disease.
The case study, which is published in JAMA Surgery, is promising news for the hundreds of thousands of people worldwide who need organ transplants.
Previous attempts to transplant animal organs into humans have often failed because human bodies reject the organs.
To overcome this, the researchers raised pigs with 10 genetic modifications, each designed to make the pigs’ kidneys more “human-like”.
They then removed the pigs’ kidneys under a general anaesthetic, and transplanted one of the kidneys into the patient, a male in his 50s.
The kidney functioned as normal in the patient, showing no signs of rejection. It immediately produced urine, and removed the waste product creatinine from the body.
“Measurement of creatinine is an indication of kidney function and ability to filter waste from blood,” explains Dr Roger Lord, a senior lecturer in medical sciences at the Australian Catholic University, and a visiting research fellow with The Prince Charles Hospital, who wasn’t involved with the study.
“The investigators were also able to demonstrate that there was no evidence of microscopic blood clot formation in the xenograft kidneys which is another indicator of normal kidney function.”
The researchers monitored the patient for 7 days before the experiment concluded.
“This case represents one of the first functional kidney transplants from a pig into a human, and shows proof of principle that organs from a genetically modified animal can replace human kidney function for one week without rejection and using conventional kidney transplant drug therapy,” says Toby Coates, a professor of medicine at the University of Adelaide and director of transplantation at the Royal Adelaide Hospital, who also was not involved with the study.
“The key advance here is the genetic removal of four pig genes that have previously proven a barrier to successful cross-species transplantation, and insertion of six human genes that prevent coagulation and ‘humanise’ the pig kidney,” says Coates.
In their paper, the researchers point out that this is a case study done on one patient, and may not be applicable to other people.
Nevertheless, they say that their study presents a “viable potential solution to an organ shortage crisis responsible for thousands of preventable deaths annually”.
“This study confirms that genetically modified, specially housed pig kidneys can correct kidney failure and function using standard kidney transplant drugs,” says Coates.
“Although in the early phase, this pilot study provides hope for the over 15,000 Australians on dialysis who could benefit from a kidney transplant, and potentially helps overcome the shortage in human donor kidneys,” he adds.
The pigs were euthanised after their kidneys were removed.
