Hope in organ transplant: Monkey who received a pig kidney survives for two years

Marking an extraordinary milestone, a kidney transplanted from a genetically engineered miniature pig has kept a monkey alive for more than two years — one of the longest survival times for an interspecies organ transplant.
This accomplishment brings us one step closer to the goal of relieving the shortage of life-saving human organs by using animal organs.This practice is known asxenotransplantation.
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 Nature journal.

Human trials of non-human organ transplants

Researchers say this study will provide more data to regulators such as the US Food and Drug Administration, which is considering whether to approve the first human trials of non-human organ transplants. It is important to dig into how feasible it will be to mass-produce pigs with such extensive editing.

Transplants from pig to human

In the past few years, researchers have transplanted pig hearts into two living people, and shown that pig hearts and kidneys can function in people who have been declared legally dead.

Xenotransplantation research has mainly focused on pigs, in part because their organs are of a comparable size and anatomy to that of humans. However, the immune systems of humans and other primates react to three molecules on the surfaces of pig cells, causing them to reject unaltered pig organs. The researchers started using the genome-editing technology CRISPR–Cas9 to disable the genes that encode enzymes that produce those molecules.

How will it turn out for humans?

Although survival times of up to two years are exceptional, Qin acknowledges that the times were more varied than the team had expected. Further, since researchers have engineered the pig genomes with people in mind, it’s likely that they would fare better in humans, says Muhammad Mohiuddin, a xenotransplantation surgeon at University of Maryland School of Medicine in Baltimore, reports Nature.

Still, the jump to humans will not be small, says Jayme Locke, a transplant surgeon at the University of Alabama at Birmingham. There are several factors to consider in this case, for instance, humans weigh much more and have a higher blood pressure than these monkeys, and it’s unknown whether the pig organs will withstand that environment, she adds.