Pigs with a small amount of monkey cells were brought to full term and were born alive in an experiment in China.
According to Science Alert, although the piglets died, their successful birth marks a major milestone for lab-grown organs.
This experiment is part of a larger effort to successfully engineer animals that can grow human organs to be harvested for transplants, called xenogeneic organogenesis.
Previously, research in this field was only taken until a point, before the embryos were terminated.
“This is the first report of full-term pig-monkey chimeras,” Tang Hai of the State Key Laboratory of Stem Cell and Reproductive Biology in Beijing told New Scientist.
Concern around the possible dangers of implanting human cells, and ethical worries should the stem cells end up in the animals brain, led this experiment team to use stem cells from crab-eating macaques.
Over 4,000 five-day-old pig embryos were injected with these cells using IVF which were then implanted into sows. Of the 10 piglets who made it to full term, only two were chimeric with the monkey cells making it into their heart, liver, lungs, spleen and skin.
All of the piglets died, though scientists think that had more to do with the IVF process than chimerism.
“Here, we have used monkey cells to explore the potential of reconstructing chimeric human organs in a large animal model,” they wrote in their paper. “The findings could pave the way toward overcoming the obstacles in the re-engineering of heterogeneous organs and achieve the ultimate goal of human organ reconstruction in a large animal.”