The fountain of youth may have been discovered after scientists found they could reverse the aging process in mammals.

Harvard researchers managed to turn the clock back for mice by helping their cellular DNA communicate more efficiently.

After just one week of restoring this communication scientists found two-year-old mice now had the body tissue of a six-month-old.

“In human years, this would be like a 60-year-old converting to a 20-year-old in these specific areas,” said Professor David Sinclair, an expert in genetics at Harvard Medical School.

Researchers discovered that the nuclear DNA — found in the nucleus of a cell — and the Mitochondrial DNA — found in other parts of the cell — stop communicating as we age. Over time this loss of communication reduces the cell’s ability to make energy, and signs of aging and disease become apparent.

“This particular component of the aging process had never before been described,” said Dr Ana Gomes, a scientist in Sinclair’s lab

The team found the communication problems were down to a depletion in a protein called NAD. When they upped the levels of NAD in the cells of mice, the ageing process reversed.

Prof Sinclair added: “The ageing process we discovered is like a married couple — when they are young, they communicate well, but over time, living in close quarters for many years, communication breaks down.

“And just like with a couple, restoring communication solved the problem. There’s clearly much more work to be done here, but if these results stand, then many aspects of ageing may be reversible if caught early.”

His team are now looking at the longer-term outcomes of the NAD-producing compound in mice and how it affects the mouse as a whole.

They are also exploring whether the compound can be used to safely treat rare diseases or more common diseases such as Type 1 and Type 2 diabetes. Longer term, the professor plans to test if the compound will give mice a healthier, longer life.

They also discovered that a molecule which switches on during ageing also switches on during cancer, in a finding that could improve treatments for the disease.

“We’re starting to see now that the physiology of cancer is in certain ways similar to the physiology of aging,” said Dr Gomes. “Perhaps this can explain why the greatest risk of cancer is age. ”

The findings were published in the journal Cell.