In late-February, scientists and researchers from Stanford University in California announced that they have successfully grown sheep embryos containing human cells. The announcement came during the annual meeting of the American Association for the Advancement in Austin, Texas and while animal rights activists have raised concerns, the ground-breaking research means that soon, supply for organ transplants might finally meet demand.
The process is called interspecies blastocyst complementation. The approach requires genetically disabling the development of a specific organ in a host embryo and introducing human cells with chimera (animal-human hybrid) formation potential.
Through the research, scientists at Stanford have found that human pluripotent stem cells (hPSCs) can integrate and differentiate in livestock species. The takeaway: soon, transplantable human tissues and organs could potentially be grown in engineered animals. But scientists are quick to say that there isn’t a concrete timeline.
‘It could take five years or it could take 10 years but I think eventually we will be able to do this.’ project lead Dr Hiro Nakuachi, a professor of genetics at Stanford, told the American Association for the Advancement of Science conference.
These findings only represent the beginning of a long road towards meeting this goal. By cell count, only about one in 10,000 cells (or less) in the sheep embryos are human. While it is still 99 percent sheep (and one percent human like you and me), it’s still worth celebrating the successful introduction of human cells.
This isn’t the first experiment of its kind. Back in 2016, researchers from the University of California, Davis successfully combined hPSCs cells with pig DNA inside a pig embryo. Over the course of the 28-day study, the human stem cells showed signs of rooting and growing into a transplantable human pancreas.
Likewise, in 2017, another Stanford team proved that a rat-grown pancreas could successfully be transplanted into a mouse with diabetes. The recipients of the pancreas only needed days of immunosuppressive therapy as opposed to life-long treatment to prevent rejection of the organ and the mice were actually cured of their diabetes.
What’s more, less than two years ago, the US government said it would approve funding on animal-hybrid experiments for the sake of organ transplantation, only to later retract their statement because of complaints from animal rights groups.
While it’s easy to understand arguments from such groups, it’s also important to understand why there is so much interest in chimeras for the sake of organ transplants. It’s possible for organs to grow to adult size within just nine months in these surrogate animals, meaning scientists could have found a much-needed solution for terminally ill patients in need of organs.
“We need to explore all possible alternatives to provide organs to ailing people.” said a member of the team and reproductive biologist Pablo Ross from the University of California, Davis.
In the US, someone is added to the organ donor list once every 10 minutes. There are currently around 76,000 people in the US and 6,500 in the UK on organ transplant lists. 32 people are dying everyday waiting for a transplant. With tens of thousands of people around the world in desperate need, it’s crucial that scientists get the funding they need to find solutions that will save them.