Pablo Ross thinks he may have the answer to the current shortage of transplantable human organs. Ross is a reproductive biologist at the University of California, Davis. He has been trying to use genetic engineering to grow human organs in pigs.
How It Works
Ross is creating chimeras — animals made from two different zygotes. He starts with a pig embryo, and removes the gene which that embryo needs to grow a specific organ, like a pancreas. He then inserts the human gene responsible for growing a pancreas.
Ross lets the embryos develop for several weeks inside a female pig before removing them and examining how the organs are differentiating.
Thus far, Ross’s experiment has not gone further than the embryonic stage, but his goal is to produce fully grown pigs that have human pancreases or other human organs. These pigs would then be slaughtered and their organs would be given to humans who need transplants.
Scientists want to do more than just create human organs with chimera experiments. They want to try to find cures for diseases. Researchers think they could use genetic engineering to produce pig-human chimeras with Parkinson’s disease, for example. These animals would serve as test subjects in experiments which seek to find cures for fatal illnesses.
Ethical Concerns
Until recently, the National Institutes of Health (NIH) imposed a moratorium on funding any experiments like Ross’s which create chimeras that are partly human. There are multiple ethical concerns surrounding these types of experiments.
One concern is the possibility of creating a non-human animal with a human brain. If a pig has human brain cells, it might possess human consciousness and be capable of human thought. There is also the possibility that two chimeras could mate and produce a human embryo; a pig could become pregnant with a human fetus.
Jason Roberts, a bioethicist at Arizona State University, said in an interview with NPR:
“One of the concerns that a lot of people have is that there’s something sacrosanct about what it means to be human expressed in our DNA. And that by inserting that into other animals and giving those other animals potentially some of the capacities of humans that this could be a kind of violation — a kind of, maybe, even a playing God.”
Lifting The Ban
The NIH announced on Thursday that it will lift the ban on funding experiments that produce chimeras that are part human. In order to be approved for funding, chimera experiments will have to abide by a number of restrictions.
For example, researchers might want to create chimeras that have human gonads, which may be useful for studying infertility. In this case, the researchers would have to take extra precautions to ensure that none of those chimeras can mate.
The new NIH rule has not forbidden experiments which create chimeras with human brain cells. The policy only says that these types of experiments would face extra review. A special committee would assess whether there is any possibility that the animal subjects could become capable of human thought.
The new NIH policy on chimera experiments will be open for public comment for 30 days, before it is formally approved.
