A human rejuvenation trial went ahead last October with results due at the end of the year, in which victims of Alzheimer's disease were given a transfusion of young blood. While it might sound a little fantastical, the hope is that it may reverse some of the damage in older patients, and the science behind it is convincing.
The idea that young blood might rejuvenate the elderly isn't especially new; after all popular culture today is saturated with vampires. The vampire myth may have held an appeal for centuries, but the concept of using young blood to rejuvenate is actually rather logical. The blood acts as a highway through the body, transporting a huge assortment of molecules released by various areas. If one organ starts to fail, this can often have a knock on effect on other tissue, spreading damage throughout the body. Cancer metastasizes by spreading through the body in this manner. Blood transfusions already save millions of lives and bone marrow transplants are equally important. Old blood often contains a different composition to healthy young blood, with varying levels of multiple factors, hormones and more - all of which dictate cellular behaviour across the body. If young blood contains a different profile, it may be that it can trigger more 'youthful' behaviour in multiple tissues.
While this may be a sound theory, considerable research has already provided proof of principle in mice. Young mice have been negatively affected by older blood, whereas older mice have undergone significant regeneration in multiple experiments including: rejuvenating stem cells, repairing hearts and improving cognition. It seems like there may actually be positive affects in multiple organ systems. It's early days, but preliminary results look promising.
“We saw astounding effects. The human blood had beneficial effects on every organ we’ve studied so far”
While initial analysis in mice showed that a specific protein GDF11 was decreased in older individuals and raising levels could be beneficial, there has been recent fears that lowering GDF11 may be a response to limit damage. The exact mechanism through which youthful blood exerts a beneficial effect isn't understood, and it's likely to be through multiple factors, but it does seem that does indeed exert a positive effect.
“Certainly you can’t drink the blood, although obviously we haven’t tried that experiment”
With the results expected soon, sourcing considerable amounts of young blood if the trial is a success could be a problem, but it may be that success will breed more research and this could translate into future treatment.
“It would be great if we could identify several factors that we could boost in older people,” he says. “Then we might be able to make a drug that does the same thing. We also want to know what organ in the body produces these factors. If we knew that, maybe we could stimulate that tissue in older people.”