Young blood and old brains

If you saw headlines earlier this month such as “’Vampire therapy’ could reverse ageing, scientists find” or “‘Vampire’ blood transfusions could cure Alzheimer’s and even be the secret to eternal youth“, you’d be forgiven for asking: “What are those scientists up to now?”. Researching the ageing process to ensure we are all able to experience healthier and happier lives in our later years is all well and good, but vampirism and eternal youth? That’s going too far. And you’d be right, it is too far, at least in terms of the headlines overstating the actual research. As we suggested in the first of our How to “Research the Headlines” guides, let’s go beneath the headlines to get the full story…

What about the actual research?

The headlines were actually based on the results of two similar studies which were published at the same time. The first study from Harvard University’s Department of Stem Cell and Regenerative Biology and led by Professor Lee Rubin, was published in the journal Science. The researchers described how the ageing brain has a diminished capacity to produce new neural cells, partly driven by a reduction in blood flow to the areas where the stem cells that can become these new cells reside. The study used a mouse model, and investigated whether it was possible to influence the environment of this area of the brain in older animals when the growth-promoting factors present in the blood of younger animals were introduced.

The methods in the study were complex, but essentially involved surgically joining the blood systems of two animals, in this case one old and one young. The animals remained joined for 5 weeks before the effects of the procedure were assessed. To allow a control comparison, animals of the same age were also joined (two young and two old). The study suggested that exposure to the systemic factors present in the young blood led to a remodelling of the blood vessels in the brain of the older animals, which resulted in better blood flow and resultant production of new neural cells.

In further experiments, the researchers noted that the changes seen in the brain were accompanied by behavioural changes, in this case assessed by performance on olfactory (smell) tests. These behavioural tests were conducted a further 5 weeks after the animals were separated from their partners – the older mice that had been exposed to the blood of younger animals performed better on the smell tests than the control animals. Furthermore, the study suggested that exposure to younger blood reversed the loss of blood vessel volume associated with age.

The researchers concluded by suggesting, “It is possible that increased blood flow might result in increased neural activity and function, opening new therapeutic strategies for treating age-related neurodegenerative conditions”. Note that the word vampire does not appear in any part of the published study.

In the second study, directed by Professor Tony Wyss-Coray at the Stanford University School of Medicine and published in Nature Medicine, the researchers used similar surgical methods as the first study (with beneficial effects on the brain structures of the older mice exposed to younger blood), they also conducted experiments where more traditional blood transfusion techniques were used. Old mice received transfusions of young blood 8 times over a 3-week period. When tested later, their performance on cognitive tasks was better than those of control animals. The authors of the study, which contains a lot more detailed analysis than summarised here, finish by saying, “the results of this study are currently limited to aged mice”, though similar to the other study they do highlight the potential for factors to be identified that might eventually help those suffering from neurodegenerative conditions (though probably not the near future). Note that the word vampire does not appear in any part of this published study either.

What did the media say?

Given the nature of the surgical procedure described, it is perhaps not surprising that sensational terms appeared in the associated media coverage. The use of the word vampire specifically, is likely to conjure images of drinking blood, rather than the surgical procedure actually used (though of course, many people would rather no such procedures were conducted on animals for research purposes, but that is another discussion). In the headlines from the Telegraph and Mirror above (though similar reports appeared in other outlets), they did at least put inverted commas around vampire, lest anyone be completely misled by the headline.

The Telegraph actually does a nice job of covering the research, and avoids most of the easy targets that other outlets strayed into in reporting these findings (just look at the opening image associated with the Scotsman’s coverage, for example). The media coverage also generally places the findings into a larger context, highlighting that this is a study in mice and not directly applicable to humans yet, for example, and giving the authors space to explain the findings in their own words.

The bottom line.

The studies demonstrate how factors in young blood might be beneficial for older brains. This is obviously at a very early stage, and is unlikely to lead to a direct human study in terms of the surgical procedure for exposing older adults to young blood. The teams are focusing on identifying which factors are of particular benefit before they could investigate introducing these in human studies (by the more conventional transfusion methods). Vampirism is therefore best avoided based on the current work, as is stopping at the headline.

Katsimpardi, L., Litterman, N. K., Schein, P.A., Miller, C. M., Loffredo, F. S., Wojtkiewicz, G. R., Chen, J. W., Lee, R. T., Wagers, A. J., & Rubin, L. L. (2014). Vascular and Neurogenic Rejuvenation of the Aging Mouse Brain by Young Systemic Factors. Science, 344, 630-634. DOI: 10.1126/science.1251141

Villeda, S. A., Plambeck, K. E., Middeldorp, J., Castellano, J. M., Mosher, K. I., Luo, J., Smith, L. K., Bieri, G., Lin, K., Berdnik, D., Wabl, R., Udeochu, J., Wheatley, E. G., Zou, B., Simmons, D. A., Xie, X. S., Longo, F. M., & Wyss-Coray, T. (2014). Young blood reverses age-related impairments in cognitive function and synaptic plasticity in mice. Nature Medicine. DOI: 10.1038/nm.3569