Of mice and ageing mankind
IT works in mice so what are the odds we humans also benefit in time?
Researchers have discovered replacing two naturally occurring molecules in the body could reverse symptoms of ageing, potentially influencing how the body responds to and performs exercise.
They found a decline in the blood flow to tissues and organs with age can be reversed by restoring molecules that improved exercise capacity and physical endurance in mice.
The two molecules could replicate the benefits of exercise, a finding that could lead to better athletic performance, improved mobility in the elderly and the prevention of ageing-associated diseases like cardiac arrest, stroke, liver failure and dementia.
For the first time the study showed as levels of the metabolite NAD+ decline with age, the body's capacity to exercise decreases because of fewer blood vessels and reduced blood flow.
By treating mice with the NAD+ booster NMN and increasing levels of hydrogen sulphide, physical endurance was extended in mice by over 60 per cent, no matter whether young or old.
Senior author Dr David Sinclair, Professor at UNSW School of Medical Sciences, says the study showed why the endothelial cells - the cells that line the blood vessels - are the main culprit in ageing and the likely reason we feel tired and have less energy as we age.
"We become weaker and less fit after 50 and eventually succumb to diseases of ageing," he said.
"Remarkably, by feeding mice NMN and H2S it restores NAD+ levels in endothelial cells and makes them believe they are young and exercised.
"With exercise the effect is even more dramatic.
"We saw 32-month-old mice, roughly equivalent to a 90-year-old human, receiving the combination of molecules for four weeks and then run, on average, twice as far as untreated mice.
"Mice treated only with NMN alone ran 1.6 times further than untreated mice."
The scientists identified this mechanism is due to a restoration of capillary formation in muscle by stimulating the activity of the protein SIRT1, a key regulator of blood vessel formation.
Lead author Dr Abhirup Das, from UNSW's School of Medical Sciences and a visiting scientist at Harvard Medical School, emphasises the significant effect NMN and H2S could have on frailty, circulation and the capacity to run.
"H2S alone has some anti-ageing properties," he said.
"But the two combined have a synergistic relationship that helped mice to run at least 50-60 per cent further.
"If these findings translate from mouse to human, we could have a revolutionary impact on the quality of life of older people.
"Age plays a critical role in the links between blood vessels and muscle and points to a loss of NAD+ and SIRT1 as the reason people lose the capacity to exercise as they age.
"It has significant impact on frailty because one of the main reasons for frailty is reduced blood flow that affects every part of our body.
"If these findings translate from mouse to human we could have a revolutionary impact on the quality of life of older people."