A monkey is still alive two years after a pig-Kidney transplant

Survival of donor kidneys with Human Genes versus Knockout: A New Way to Protect Your Kidneys Against Rejection and Other Rejections

The donor kidneys with the human genes survived seven times longer than the ones that only had the three pig genes knocked out—a median of 176 days versus 24. This suggests that adding the human genes offers some protection against rejection, the study authors say. The longest-living monkey, which survived 758 days after the transplant, received kidneys that had the added human genes. The animals like these organs very much.

It’s possible for a person to excrete waste, produce urine, and balance fluids. In the United States alone, nearly 88,000 people are waiting for a kidney donation, according to data from the federal Organ Procurement and Transplantation Network. In 2022, only about 26,000 received one.

The Most Extensive Editing in Live Pigs for Xenotransplantation, Reveals Wenning Qin, MD, a Biotech Consultant, and a Medical Biologist

Qin and her colleagues edited 69 genes, which is the most extensive editing done in live pigs for xenotransplantation. Three edits are directed at the rejection-related molecules, while 59 edits target retroviruses that embedded in the pig genomes long ago. Previous research5,6 has shown that, in a laboratory setting, these embedded genomes can produce viral particles that infect human cells, but the infection risk to human xenotransplant recipients and their transplanted organs is unclear.

This is a “proof of principle in non-human primates to say our [genetically engineered] organ is safe and supports life”, says Wenning Qin, a molecular biologist at the biotech firm eGenesis in Cambridge, Massachusetts, who co-authored the study published in Nature1 on 11 October.

In the past few years, researchers have demonstrated pig hearts and kidneys can function in people who have been declared legally dead.

Such research is crucial, given the dearth of suitable organ donors, says David Cooper, a xenotransplant immunologist at Massachusetts General Hospital in Boston, who was not involved with the study but is a consultant for eGenesis. In the United States alone, more than 100,000 people are awaiting an organ transplant, and about 17 of them die each day.

The last seven edits are additions of human genes that help to keep the transplanted organ healthy. There are two genes that prevent unnecessary blood clotting.

Although survival times of up to two years are exceptional, Qin acknowledges that the times were more varied than the team had expected. The pig genomes were engineered so that they would be better suited for humans, Mohiuddin says.

Some researchers don’t believe that extensive genetic changes are necessary. Megan Sykes is an immunologist at Columbia University Medical Center in New York City.

She says that the survival is not much better than before with many fewer genes modified. She says that with every extra gene modification, they become harder to produce which may make it harder to scale up.

In principle, Mohiuddin agrees that some of these edits might be “overkill”, but he is optimistic that one day there will be genetically modified pigs that eliminate the need for immunosuppressive drugs.

Locke thinks we don’t know how complex these edits need to be. Clinical trials are going to be very important at that location.