Scientists have reversed the effects of ageing on the skin of mice by blocking the action of a specific protein.
Several genes have been implicated in skin cell ageing
In two-year old mice, Californian researchers found that they could rejuvenate skin to look more youthful.
Further analysis published in the journal Genes and Development showed the skin had the same genetic profile as the skin of newborn mice.
The team said the research would most likely lead to treatments to improve healing in older human patients.
They stressed it was unlikely to be a potential "fountain of youth" but could help older people heal as quickly from injury as they did when they were younger.
The protein in question - NF-kappa-B - is thought to play a role in numerous aspects of ageing.
It acts as a regulator, causing a wide range of other genes to be more or less active.
Lead researcher, Dr Howard Chang, from the Stanford School of Medicine in California, said the findings supported the theory that ageing is the result of specific genetic changes rather than accumulated wear and tear.
And that it is possible to reverse those genetic changes later in life.
Previous studies have identified several genes which play a part in the ageing process.
Dr Chang and colleagues spotted that the one thing the genes had in common was that they were regulated by NF-kappa-B, which can either make them more or less active.
By blocking the protein in older mice for two weeks, they found the skin was thicker and more cells appeared to be dividing, much like the skin of a younger mouse.
And the same genes were active as in the skin of newborn mice.
It is unclear whether the effects are long-lasting and the protein has also been implicated in cancer and regulation of the immune system.
"We found a pretty striking reversal to that of the young skin," Dr Chang said.
But he added any application in humans was likely to be on a short-term basis because of other effects of blocking the protein.
"You might get a longer lifespan but at the expense of something else," he said.
Nina Goad from the British Association of Dermatologists said: "Targeting of gene therapy to skin is still very difficult but this may provide some new avenues of research that will be of value to wound healing, following skin trauma or disfiguring skin cancer surgery.
"However, the researchers' caveats about the unforeseen consequences of manipulating genes that play a role in many cells are most important and add a strong element of caution."