In a bid to save lives of those on organ donation waiting lists, human organs are being grown inside sheep and pigs. More than 50 sheep and pigs have been implanted with human-animal hybrid embryos with the aim of them developing into fully functional human hearts, livers and other major organs.
The experiments rely on a cutting-edge fusion of technologies, including recent breakthroughs in stem-cell biology and gene-editing techniques. By modifying genes, scientists can now change the DNA in pig or sheep embryos so they are genetically incapable of forming a specific tissue.
Then, by adding stem cells from a person, they hope the human cells will take over the job of forming the missing organ, which could then be harvested from the animal for use in a transplant operation. The US research was carried out at the National Institutes of Health in Maryland.
Daniel Garry, a cardiologist who leads a chimera project at the University of Minnesota, said:
‘We can make an animal without a heart. We have engineered pigs that lack skeletal muscles and blood vessels.’