The new research papers show clear proof of how the process works and offer an explanation: The key is in the levels of some proteins that are more abundant in the younger blood and seem to awaken the stem cells, causing the creation of new, young tissue.
Rejuvenating brains...The first study--published in Nature Medicine and led by University of California's Saul Villeda—says that the transfusion of blood through parabiosis works and that extracting the plasma from the younger mice and injecting it into the older individuals' brain works even better. The process creates new neuronal connections, reversing the effects of age, and greatly improving the mice's cognitive functions:
At the cognitive level, systemic administration of young blood plasma into aged mice improved age-related cognitive impairments in both contextual fear conditioning and spatial learning and memory. Structural and cognitive enhancements elicited by exposure to young blood are mediated, in part, by activation of the cyclic AMP response element binding protein (Creb) in the aged hippocampus. Our data indicate that exposure of aged mice to young blood late in life is capable of rejuvenating synaptic plasticity and improving cognitive function.
This discovery could be key to beat Alzheimer's disease and other degenerative brain conditions caused by aging.
...and heartsThe second study, published in Science by a team led Harvard University's Dr. Amy J. Wagers, shows that the the high levels of the protein GDF11 present in young blood turned back the clock on the hearts of the old mice. This protein revives the stem cells in the older mice, causing the creation of new tissue to replace the old.
Dr. Wagers was a member of the team that initially looked again into Dr. McCay's research, led by Stanford University's professor of neurology Dr. Thomas Rando. Rando has been studying longevity and aging in humans for a long time. Here's a really interesting video in which he discusses the process and factors for the prevention of aging.
There's only two caveats. The first is that these are experiments with mice. They still have to be tested in humans, who have their own version of GDF11. It will probably work in the same way, but we don't know for sure yet.
The second one is cancer. The moment you start awakening stem cells and telling them to start creating new cells, you may increase the possibilities of cancer. Honestly, I would rather take the chance of cancer than the certainty of dementia or early death because of some heart disease.
That's why scientists are so excited. The results are clear and there are no conflicts between the two studies, so this is wonderful news so far, they say. The director of the Center for Molecular Medicine at the National Heart, Lung and Blood Institute Dr. Toren Finkel told the New York Times that these studies show that "we can turn back the clock instead of slowing the clock down. That's a nice thought if it pans out."
Source: gizmodo.com by Jesus Diaz