Rejuvenative Properties of ‘Young Blood’
By Corinne Atkinson
Could vampirism reverse aging? While the thought of consuming blood, human blood, may be inconceivable outside the context of folklore or even pop culture as a result of the popularity of The Twilight Saga, it may not be so far-fetched. As new technologies and scientific advancements have increased the average life-span, research efforts aimed at further improving longevity have expanded dramatically. A particular interest within this area of scientific exploration involves the investigation of potential ‘youthful’ properties of blood. It appears initial research findings may be in favor of a vampire-esque lifestyle, but some controversy remains.
In a study published in 2014, a group of scientists led by Wyss-Coray, a renowned investigator in aging research, produced astonishing findings that blood may in fact play a crucial role in aging, especially as it relates to brain function. While the idea that blood has rejuvenating properties is not a new idea, Wyss-Coray and his colleagues took a novel approach by investigating the potential link between “young blood” and cognitive impairments related to aging. In order to do so, they implemented heterochronic parabiosis, which refers to the surgical conjoinment of an old mouse with a young mouse, to establish findings on how young blood may affect the brain. Using this paradigm, which allows for direct exposure to young blood through shared circulation, they found enhanced neural plasticity among the older mice, particularly in the hippocampus. Neural plasticity refers to the ability of the brain to rewire and strengthen neural connections, a trait that is often thought to be diminished with age. The hippocampus is a brain region associated with memory and is implicated in Alzheimer's Disease, a common neurological disorder that affects older adults and is characterized by dementia (Villeda et al., 2014). Thus, their findings have substantial implications about a potential effect of young blood exposure on cognition.
To further investigate the potential link between blood and cognition, the researchers tested mice for cognitive decline using a learning-based paradigm before and after injecting subject mice with “young” or “aged” blood plasma from three-month or 18-month-old mice, respectively. In a test involving a hidden platform, the scientists found significant improvements in memory and learning in the mice injected with young plasma compared to the mice injected with aged plasma and the untreated control group. The authors suggest that the beneficial effects of young blood may result from improved neurogenesis and synaptic plasticity (Villeda et al., 2014). The enhanced ability of the aged brain to grow new neurons and strengthen interneuron connections would likely result in a maintenance of ‘normal’ brain function. Thus, the resulting increase in malleability of the aged brain would ultimately provide a mechanism against age-related cognitive decline.
These conclusions have profound implications on the future direction of treatment and prevention of age-related degeneration. Still, more research needs to be conducted to determine the directionality of effect: Do components of ‘young blood’ positively impact cognition and brain plasticity, or is it rather the amelioration of components of old blood that have the proposed effect? Based on the experiment conducted by Wyss-Coray, it would seem that some element of youthful blood produces the appearance of anti-aging effects. However, another study found that old blood could inhibit learning in young mice and reduce plasticity in the hippocampus (Rebo et al., 2016). This would be suggestive of the alternate conclusion.
Based on the potential to reverse, or at least slow, the progression of aging, there may come a day when the elderly rely on the youth for their blood... blood transfusions, that is. Nevertheless, the inconclusivity of results relating to the connection between blood and aging may not warrant the temptation to become a vampire just yet.
Rebo, J., Mehdipour, M., Gathwala, R., Causey, K., Liu, Y., Conboy, M. J., & Conboy, I. M. (2016). A single heterochronic blood exchange reveals rapid inhibition of multiple tissues by old blood. Nature communications, 7, 13363.
Villeda, S. A., Plambeck, K. E., Middeldorp, J., Castellano, J. M., Mosher, K. I., Luo, J., … Wyss-Coray, T. (2014). Young blood reverses age-related impairments in cognitive function and synaptic plasticity in mice. Nature medicine, 20(6), 659–663. doi:10.1038/nm.3569