This Thursday, a genetically modified pig kidney transplant was successfully performed on a 62-year-old patient in the US.
The Massachusetts-based patient named Richard (Rick) Slayman underwent a four-hour surgery on March 16, is currently recovering well, and is expected to be discharged soon. Rick has previously received a human kidney transplant that showed signs of failure after five years.
Xenotransplantation, the process of transplanting organs from animals to humans, is a brimming hope to tackle the shortage of donated organs worldwide.
However, specific essential measures are taken to ensure a successful transplantation of animal organs into humans. The procedures are needed to minimize the risk of rejection by the recipient’s immune system and to prevent infection and other possible complications.
Previously, pig kidneys have been successfully transplanted into brain-dead recipients.
Table of Contents
Genetically modified transplants: a hope for the future
The pig kidney used in the surgery was genetically modified using the gene editing technology known as CRISPR-Cas9. This technique is used to make animal kidneys more compatible with humans.
The modifications take place in a series of three steps. Firstly, to make the pig kidney more compatible with humans, the pig genes are removed. These genes produce sugars that cause reactions in the immune system.
Secondly, human genes are added to the pig kidneys to improve their compatibility. Last, the porcine endogenous viruses are deactivated in the donor pig to ensure the recipient does not get infected. These viruses are present in all pig genomes and can cause infections in the recipient.
The donor pig’s kidney has undergone 69 genomic edits in total. The modified kidney was provided by the company eGenesis, which focuses on xenotransplantation therapy. Co-founder George Church, a Harvard Medical School(HMS) geneticist, and his team have extensively researched the challenges of using pig kidneys for transplantation.
Challenges to pig kidney transplant
Pig kidneys are very similar to human kidneys in size and function. However, stopping the human immune system from reacting to them has been difficult.
The human immune system shows much stronger reactions to pig organs than to human organs. This has been a primary challenge when performing xenotransplantation.
Recent advances have enabled scientists and doctors to achieve successful pig kidney transplantation. eGenesis using CRISPR-Cas9 technology to make 69 edits in the pig’s DNA, making special antibodies that prevent the rejection of pig organs in the human body, and finally, testing of pig-organs in non-human animal models have been the critical steps in eliminating the challenges in xenotransplantation.
Will the pig kidney transplant work?
The long-term results of such kidney transplants have yet to be discovered since it is the first time they have been performed.
“We still don’t know how many years this kidney can survive, but based on our preclinical research, we are aiming at years — more than two years,” said Kawai, lead surgeon for the pig transplant from Massachusetts General.
The surgery becomes a success if Rick does not return to dialysis, who has been suffering from Type-2 diabetes and hypertension. After his human kidney transplant surgery back in 2018, he returned to dialysis upon signs of failure again.
Kidney xenotransplantation is a new hope for patients worldwide who are suffering from diseases like diabetes and hypertension, both of which increase the risk of kidney failure. Such initiatives can save the lives of thousands of people who are unable to undergo kidney transplantation due to a lack of donors.
