Mayo Clinic researchers have achieved a breakthrough in the road to ending ageing by extending the lifespans of mice by between 17% and 35%, in research that could one day be replicated in humans.

The researchers found that by clearing senescent cells – that is, cells that have stopped dividing and which grow in number as we age – they were able to not only extend the mice’s lifespans, but also preserve tissue, maintain organ function and delay the formation of tumours. The mice also looked healthier, and had less tissue inflammation than their normally ageing counterparts.

“Cellular senescence is a biological mechanism that functions as an ’emergency brake’ used by damaged cells to stop dividing,” said study senior author Dr Jan van Deursen, Mayo Clinic chair of biochemistry and molecular biology.

“While halting cell division of these cells is important for cancer prevention, it has been theorized that once the ’emergency brake’ has been pulled, these cells are no longer necessary.”

Senescent cells are known to cause chronic inflammation and damage to nearby healthy cells, which are thought to be key drivers of age-related disease. Immune systems do have their own mechanisms for clearing out senescent cells, but these become less and less effective with age.

“Senescent cells that accumulate with ageing are largely bad, do bad things to your organs and tissues, and therefore shorten your life but also the healthy phase of your life,” added van Deursen.

The researchers were able to clear out the leftover senescent cells in mice using a drug compound known as AP20187 assisted by a transgene – a genetic material transferred from another organism. The mice themselves were not genetically altered.

The results were healthier mice that lived longer and looked younger in the process, without any observable side-effects; a remarkable step in combating the ageing process.

If such findings were replicated in humans it would be of enormous significance, and excitingly the researchers do believe that their research could be the path to human-suitable treatments for ageing.

“Since you can eliminate the cells without negative side effects, it seems like therapies that will mimic our findings – or our genetic model that we used to eliminate the cells – like drugs or other compounds that can eliminate senescent cells would be useful for therapies against age-related disabilities or diseases or conditions,” said van Deursen.

The lead author of the study, which is published today in the journal Nature, was also optimistic about the possibilities for human treatments.

“The advantage of targeting senescent cells is that clearance of just 60-70 percent can have significant therapeutic effects,” said study lead author and Mayo Clinic molecular biologist Dr Darren Baker. “If translatable, because senescent cells do not proliferate rapidly, a drug could efficiently and quickly eliminate enough of them to have profound impacts on healthspan and lifespan.”