Suicide of ageing cells boosts longevity

In a landmark study of "middle-aged" mice, scientists have provided evidence that zapping run-down cells that make you age extends the animals' lives, raising intriguing prospects for anti-aging treatments.

According to a research paper in the journal Nature, cells senesce - or age - after suffering DNA damage or other types of stress, and by removing senescent cells from the mice, the rodents went on to enjoy better kidney function and stronger hearts, a later onset of cancer and fewer cataracts than untreated peers.

They also lived longer.

"The mice that were treated to remove their senescent cells had a lifespan extension... from 25 to 35 percent," study co-author Darren Baker of The Mayo Clinic College of Medicine in Minnesota said.

"We found at 18 months of age, so after six months of treatment, the treated animals were more exploratory, more active, they had also improvements in kidney function, in heart function..." he said.

The benefits extended to both genders, and different strains of mouse.

the treated animals were more exploratory, more active, they had also improvements in kidney function, in heart function - Study co-auther Darren Baker

"In all cases we found that there is a significant health and lifespan extension," Baker explained in a recording made by Nature.

The team genetically-engineered mice in which senescent calls can be easily eliminated by using drugs to trigger a cellular "suicide gene".

Senescent cells are cells which have stopped dividing, and no longer function. Some are shed naturally, but others accumulate in organs over time.

They have been speculated to have a role in ageing.

"We knew that senescent cells were accumulating with age in natural tissues and the thought was: let's just start removing these things starting at mid-age in mice and see what the consequences were," Baker said.

'Not far-fetched'

The results suggested "this approach may be useful to treat aspects of age-related functional decline, age-related diseases that involve senescent cells, or side effects of therapies that create senescent cells," the study authors wrote.

A future step in research would be to test the method on already aged mice, to see if removing senescent cells can reverse age-related decline.

Since we cannot engineer humans with the so-called "suicide gene," the method cannot be directly tested in our own species, Baker explained.

Since we cannot engineer humans with the so-called 'suicide gene,' the method cannot be directly tested in our own species - Darren Baker

"But there are a variety of groups that we know of that are specifically looking for compounds that can selectively eliminate these senescent cells with age that accumulate in you and I," he said.

"So it is not a far-fetched idea to think that there will be things that will be coming down the pipeline that influence or remove these senescent cells."

Anti-ageing drug

Researchers have already proven that metformin, a drug used to fight diabetes, extends the life of animals.

A trial in the US next year will test the effect of metformin on humans to see if the same results will be achieved. Scientists believe that it could help people live healthier lives well into their 110s and 120s, raising middle-age in humans to nearly 70 years of age.

Metformin is quite cheap and widely used by diabetics. It increases the number of oxygen molecules released into the cell making them remain healthy and live longer.

Ageing is associated with a progressive decline in cognitive function as well as physical deterioration, and finding a "cure" has been a long-held dream of science.

In May 2014, researchers reported that injections of young mouse blood boosted learning and memory in older rodents.