The origins of the technique stem from the 1990s, when researchers at the Roslin Institute just outside Edinburgh developed a method of turning an adult mammary gland cell taken from a sheep into an embryo. It led to the creation of Dolly the cloned sheep.
The Roslin team’s aim was not to create clones of sheep or indeed humans, but to use the technique to create so-called human embryonic stem cells. These, they hoped, could be grown into specific tissues, such as muscle, cartilage, and nerve cells to replace worn-out body parts.
The Dolly technique was made simpler in 2006 by Prof Shinya Yamanaka, then at Kyoto University. The new method, called IPS, involved adding chemicals to adult cells for around 50 days. This resulted in genetic changes that turned the adult cells into stem cells.
In both the Dolly and IPS techniques, the stem cells created need to be regrown into the cells and tissues the patient requires. This has proved difficult and despite decades of effort, the use of stem cells to treat diseases is currently extremely limited.
Prof Reik’s team used the IPS technique on 53-year-old skin cells. But they cut short the chemical bath from 50 days to around 12. Dr Dilgeet Gill was astonished to find that the cells had not turned into embryonic stem cells – but had rejuvenated into skin cells that looked and behaved as if they came from a 23-year old.
He said: “I remember the day I got the results back and I didn’t quite believe that some of the cells were 30 years younger than they were supposed to be. It was a very exciting day!”
The technique cannot immediately be translated to the clinic because the IPS method increases the risk of cancers. But Prof Reik was confident that now it was known that it is possible to rejuvenate cells, his team could find an alternative, safer method.
“The long-term aim is to extend the human health span, rather than the lifespan, so that people can get older in a healthier way,” he said.
Prof Reik says some of the first applications could be to develop medicines to rejuvenate skin in older people in parts of the body where they have been cut or burned – as a way to speed up healing. The researchers have demonstrated that this is possible in principle by showing that their rejuvenated skin cells move more quickly in experiments simulating a wound.
The next step is to see if the technology will work on other tissues such as muscle, liver and blood cells.