Transfusions of young blood could reverse the ageing process and even cure Alzheimer's disease, American scientists believe.
In a breakthrough that could herald a new dawn in anti-ageing treatments, researchers found that young blood "recharges" the brain, forms new blood vessels and improves memory and learning.
Meanwhile, scientists at Harvard University discovered that a "youth protein" which circulates in the blood is responsible for keeping the brain and muscles young and strong.
The protein, known as "GDF11", is present in the bloodstream in large quantities when we are young but peters out as we age. Although both the discoveries were made in mice, researchers are hoping to begin human trials in the next two to three years, in studies that could bring rapid improvements for human longevity and health.
“This should give us all hope for a healthier future,” said Prof Doug Melton, from Harvard's department of stem cell and regenerative biology.
“We all wonder why we were stronger and mentally more agile when young, and these two unusually exciting papers actually point to a possible answer.
“There seems to be little question that GDF11 has an amazing capacity to restore ageing muscle and brain function.”
Last year the team discovered that the protein could repair damaged hearts.
But the new study showed that raising the levels of the GDF11 protein in older mice improved the function of every organ in the body.
Prof Lee Rubin, a Harvard stem cell biologist, added: “We do think that, at least in principle, there will be a way to reverse some of the decline of ageing with a single protein. It isn't out of the question that GDF11, or a drug developed from it, might be worthwhile in (treating) Alzheimer's disease.”
It is likely that the protein is at least partly responsible for the parallel finding by Stanford University that young blood can reverse the signs of ageing.
In the study, the blood of three-month-old mice was repeatedly injected into 18-month-old mice near the end of their natural life span. The “vampire therapy” improved the performance of the elderly mice in memory and learning tasks. Structural, molecular and functional changes were also seen in their brains, the study published in the journal ‘Science’ found.
If the same were seen in humans, it could lead to new therapies for recharging our ageing brains and novel drugs for treating dementia.
Ageing mice given eight infusions of young blood over three weeks improved their performance in mental tests such as locating a hidden platform in a water maze.
Tony Wyss-Coray, from Stanford University, the lead researcher.
“You don't need to know anything about how the brain works. You just give an old mouse young blood and see if the animal is smarter than before.
“It's just that nobody did it,” Dr Wyss-Coray added.