The world has long been fascinated with the idea that
the blood of young people could have rejuvenating qualities, like a
glorious fountain of youth, only horrifying. Turns out the world is sort
of right.

A new study by researchers at Stanford University shows that
injections of young blood can reverse the signs of aging in mice. The
experiment is as simple as it sounds. Give an old mouse a syringe full
of blood from a young mouse, and run some tests. Leader of the research
team Saul Villeda and his team found that the boost of youth improved
learning and memory in the older mice. Villeda shared his research with
the Society for Neuroscience conference in New Orleans on Wednesday and
did not understate its implications for conditions that are caused by
deteriorating brain function. "I think any sort of disease that has that
component, there is a chance this might help," he said. "What I am
thinking is if we can address it earlier, when our body still has the
control to prevent this from happening, then we might not have to cure
Alzheimer's, we might just be able to stop it."

This is crazy, because in the past, crazy people have latched on to
the idea that young blood could get them closer to immortality. Kim
Jong-il, for example, used to "inject himself with blood from healthy
young virgins in a bid to slow the aging process," according to The Guardian.
Quite remarkably, it now appears that Kim Jong-il wasn't aggressive
enough. Villeda actually supplied a group of 18-month-old (read: very
old) mice with eight transfusions over the course of a month -- that
amounts to about 5 percent of a mouse's blood supply -- and found that
the brain connections in the older mice had increased by 20 percent
after the treatment. "One of the main things that changes with ageing
are these connections, there are a lot less of them as we get older,"
said Villeda. "That is thought to underlie memory impairment -- if you
have less connections, neurons aren't communicating, all of a sudden you
have [problems] in learning and memory."

This is actually not the first study to suggest that young blood
reverses signs of aging. In 2010, a team of Harvard researchers
connected the circulatory systems of young and old mice so that their
blood mixed and found that it rejuvenated the blood-forming stem cells
in the older mice. In the words of MIT's Technology Review,
"They found that the procedure made the blood-forming stem cells in
older animals act young again." The biggest difference in that study
seems to be the mice's ability to produce immune cells, though it's
unclear exactly what the long term effects of the blood mingling would
have on the animals.