In this state, the cells are in effect dormant, as they have stopped dividing but still persist.
It works by targeting a particular protein, FOXO4, which in normal senescence is thought to stop the cell from dying.
"Only in senescent cells does this peptide cause cell death", says senior author Peter de Keizer, a researcher of aging at Erasmus University Medical Center in the Netherlands. By interfering with the FOXO4-p53 crosstalk, the peptide causes senescent cells to go through apoptosis, or cell suicide.
"It was found that these senescent cells secrete a whole load of junk and they're not just bystanders but have a negative effect", said De Keizer. "The common thread I see for the future of anti-aging research is that there are three fronts in which we can improve: The prevention of cellular damage and senescence, safe therapeutic removal of senescent cells, to stimulate stem cells-no matter the strategy-to improve tissue regeneration once senescence is removed". The mouse on the right was not treated with the peptide. The mouse on the left was treated with a FOXO4 peptide, which targets senescent cells and leads to hair regrowth in ten days.
Research published a year ago showed that removing the cells using a genetic trick caused mice to live 20% longer on average.
Senescent cells have some beneficial roles in the body. The latest paper is the first to show that ageing cannot only be delayed by removing senescent cells - but potentially reversed.
Researchers infused a peptide into normal nice and into mice genetically engineered to rapidly age. Scientists told the Guardian Thursday their study could push the world one step closer to the discovery of life-extending treatments, as well as cures for the side effects of time on the human body.
Initially the scientists planned to simply assess kidney function, but a laboratory technician pointed out that some of the balding mice had undergone a remarkable physical transformation. The animals' sluggish disposition also changed and they started moving around more and exploring their cages.
Fast-ageing mice with patches of missing fur began to recover their coats after 10 days and after about three weeks, the fitness benefits began to show, with older mice running double the distance of their counterparts who did not receive the anti-senescence treatment.
A treatment administered to lab mice appeared successfully to remove inactive - otherwise known as senescent - cells damaged over time, allowing the reproduction of healthy new cells to take their place.
According to BBC News, Dr. Peterde Keizer and his colleagues discovered that by using a specific type of peptide (a short chain of amino acid monomers linked by covalent chemical bonds), they could reverse aspects of aging by flushing out cells which no longer divide.
The team plan to carry out a safety clinical trial in people with an aggressive form of brain tumour, called Glioblastoma multiforme, in which cells happen to feature a similar marker to those in senescent cells, making the peptide a possible treatment for this form of cancer.