Researchers in the US are closing in on a therapy that could reverse harmful ageing processes in the brain, muscles, heart and other organs.
Hopes have been raised by three separate reports released by major journals yesterday that demonstrate in experiments on mice the dramatic rejuvenating effects of chemicals found naturally in young blood.
Infusions of young blood reversed age-related declines in memory and learning, brain function, muscle strength and stamina, researchers found. In two of the reports, scientists identified a single chemical in blood that appears to reverse some of the damage caused by ageing.
Although all three studies were done in mice, researchers believe a similar rejuvenating therapy should work in humans. A clinical trial is expected to begin in the next three to five years.
“The evidence is strong enough now, in multiple tissues, that it’s warranted to try and apply this in humans,” said Saul Villeda, first author of one of the studies at the University of California in San Francisco.
Ageing is one of the greatest risk factors for a slew of major conditions, from cancer and heart disease to diabetes and dementia. As the population grows older, the proportion of people suffering from such conditions soars. A therapy that slows or reverses age-related damage in the body has the potential to prevent a public health crisis by delaying the onset of several diseases at once.
The three studies took a similar approach to investigate the anti-ageing effects of young blood. Old and young mice were paired up and joined like conjoined twins. To do this, researchers made an incision along the side of each mouse and let the wounds heal in a way that joined the animals together. The procedure meant that the mice shared each other’s blood supplies.
Villeda found that blood from three-month-old mice reversed some age-related changes in the brains of 18-month-old mice. The animals grew more and stronger neural connections in a region called the hippocampus, meaning the brain cells could talk to each other more effectively, according to a report in Nature Medicine. An 18-month-old mouse is considered to be equivalent in age to a 70-year-old person.
Villeda went on to inject blood plasma - or blood without the blood cells - from young mice into older animals. The infusions had a striking impact on the animals’ performance. Aged rodents given young blood plasma found their way around a water maze as well as six-month-old mice, and reacted like three-month-olds in an experiment that tested how well they remembered a threatening environment.
“There’s something about young blood that can litreally reverse the impairments you see in the older brain,” Villeda said. But he stressed that mice were not humans. “I wish our manuscript could come with a big caption that says ‘Do not try this at home’. We need a clinical trial to see if this applies to humans, and to see if there are effects that we don’t want.”
Villeda said the anti-ageing effect was linked to a protein called Creb that acts like a master regulator in the brain. Young blood plasma makes Creb more active, and this turns on genes that drive neural connections.