Calling to mind the sci-fi tale of Dr Moreau and his monstrous experiments, US scientists have created the first ever human-pig embryos and hybrid “chimeras”
Using stem cell technology, Californian geneticists have found success in attempting to generate human cells and tissues in the embryos of pigs and cattle.
In the study published this week in Cell, researchers sought to discover the capability of human stem cells to “integrate and differentiate” in an animal embryo.
The researchers’ ultimate purpose is to generate transplantable human tissues and organs, in order to address the worldwide shortage of organ donors.
Pigs were used because both the size and the development time for their organs are more similar to our own than rats or mice.
Human cells implanted within some of the embryos had begun to “specialise” and turn into tissue precursors, the researchers discovered.
However, the success rate and level of human stem cell contributions in pigs was much lower than in the rat-mouse chimeras they also managed to create.
Integrating cells from human and animal species is proving difficult and developing human organs remains at a considerable distance, lead author Dr Jun Wu told CNN.
He advised that the research is still in its very early stages.
“Species evolve independently, and many factors dictating the developmental programs might have diverged, which makes it difficult to blend cells from one species to a developing embryo from another,” Wu says.
“The larger the evolutionary distance, the more difficult for them to mix.”
Wendy Harmer spoke with ethicist and philosopher Matthew Beard about the experiments on ABC Radio.
“Is it right to create a new kind of beast for our own vanity?” Ms Harmer asked.
“There’s a part where people feel squeamish about the whole idea, and that has something to do with the way that we elevate humans above animals,” suggested Mr Beard.
“If we think about the idea of developing some kind of a pig that has human stem cells at its basis, in order to harvest it for organs it becomes hard to avoid the fact that there are pigs who are used and grown to be harvested for meat across the world.
“And whether we can make a kind of ethical distinction between those two things is probably lurking in the back of a lot of people’s judgements and feelings about this as well.”
He also highlighted the importance of processes and ethics committees in assessing such experiments.