Blood is NOT the eternal youth elixir
We live in a society permanently obsesed with the idea of youth. Therefore, it is not surprising to find supposedly miraculous potions, ointments and elixirs that offer precisely that. But the idea of permanent youth is not a new idea, it comes from way back, as does the notion that young blood would help rejuvenate those chosen by the powers-to-be. But how much truth is there in those legends of old?
The answer is provided by science, as could not be otherwise. Very recently, in a short article in Nature, Justin Rebo and colleagues dismantled this notion while proving that the opposite is also true. Meaning? That even though drinking or getting a transfusion with young blood won’t help you get rid of your wrinkles, old blood could have undesirable effects on adult neurogenesis, among others.
But let’s get into the details of the research, shall we?
The authors of this article took 4 pairs of mice old/young and developed a system to ensure reciprocal blood transfusion. In parallel, as controls they had 4 pairs of youg/young and 4 more of old/old mice that also exchanged blood to make sure that whatever changes they uncovered were due to the young/old combination and nothing else. Then they assessed several parameters both in the old animals receiving young blood and in the younger getting the aged blood.
In summary, they found that while young blood produces a fast improvement on hepatic and muscle health, it has no effect on adult neurogenesis in the hippocampus. The authors think that a plausible reason for this improvement lies in the dilution of old blood produced with the young one, and with it, the dilution of potentially toxic factors contained in the old blood. The evidence supporting the existence of deleterious/toxic factors in old blood is supported by the fact that in the converse scenario, when a young animal received old blood, this had a strong, fast and lasting effect on neurogenesis, which was strongly impaired after this transfusion. When looking into the molecular mechanisms, the authors reported a rapid increase in beta-2 microglobulin (B2M) in young tissues by old blood, an increase that wasn’t due to high circulating levels of B2M in the old blood but to other unknown mechanisms, possibly by inflammation. Other possible suspects for the toxic effects of old blood are TGF-beta1 (tumour growth factor), diminishing oxytocin levels…However, to discriminate who are the culprits, more research is needed.
So, I am sorry to tell all of you potential vampires that your efforts would not really be worth it. You will not live eternally from taking someone else’s blood, worse still, you could even age faster if you choose the wrong candidate*.
Rebo, J. et al. A single heterochronic blood exchange reveals rapid inhibition of multiple tissues by old blood. Nat. Commun. 7, 13363 doi: 10.1038/ncomms13363 (2016).
Further reading:
Conboy, I. M., Conboy, M. J. & Rebo, J. Systemic problems: a perspective on stem cell aging and rejuvenation. Aging 7, 754–765 (2015).
Villeda, S. A. et al. The ageing systemic milieu negatively regulates neurogenesis and cognitive function. Nature 477, 90–94 (2011).
*I guess it’s quite obvious but it is better if we clear the concepts for once. That sentence is a joke, and fact just cannot be extrapolated from a single piece of scientific work in rodents. But just in any case, don’t go around drinking blood 😛