A LITTLE stress is all it took to make new life from old. Adult cells have been given the potential to turn into any type of body tissue just by tweaking their environment. This simple change alone promises to revolutionise stem cell medicine.
Yet New Scientist has also learned that this technique may have already been used to make a clone. “The implication is that you can very easily, from a drop of blood and simple techniques, create a perfect identical twin,” says Charles Vacanti at Harvard Medical School, co-leader of the team involved.
Details were still emerging as New Scientist went to press, but the principles of the new technique were outlined in mice in work published this week. The implications are huge, and have far-reaching applications in regenerative medicine, cancer treatment and human cloning.
In the first few days after conception, an embryo consists of a bundle of cells that are pluripotent, which means they can develop into all cell types in the body. These embryonic stem cells have great potential for replacing tissue that is damaged or diseased but, as their use involves destroying an embryo, they have sparked much controversy.
To avoid this, in 2006 Shinya Yamanaka at Kyoto University, Japan, and colleagues worked out how to reprogram adult human cells into what they called induced pluripotent stem cells (iPSCs). They did this by introducing four genes that are normally found in pluripotent cells, using a harmless virus.
The breakthrough was hailed as a milestone of regenerative medicine – the ability to produce any cell type without destroying a human embryo. It won Yamanaka and his colleague John Gurdon at the University of Cambridge a Nobel prize in 2012. But turning these stem cells into therapies has been slow because there is a risk that the new genes can switch on others that cause cancer.