For me it sounds a bit crazy, but experiments on mice have shown that it is possible to rejuvenate the brains of old animals by injecting them with blood from the young.
Scientists from Stanford University found that blood from young mice reversed some of the effects of ageing in the older mice, improving learning and memory to a level comparable with much younger animals. This technique could one day help people stave off the worst effects of ageing, including conditions such as Alzheimer's.
They connected the circulatory systems of an old and young mouse so that their blood could mingle, after that several clear signs were found that the ageing process had slowed down. The number of stem cells in the brain, for example, had increased. More important, researchers found a 20% increase in connections between brain cells.
He took blood plasma – the fluid portion of blood that is not cells – from two-month-old mice and injected small amounts, around 5% of the total amount of blood in a mouse by volume, into 18-month-old animals eight times over the course of a month.
Author said that the young blood most likely reversed ageing by topping up levels of key chemical factors that tend to decline in the blood as animals age. Which factors in particular are causing the effect is unclear since there are hundreds of thousands in blood.