Circulating factors present in young mice have been shown to promote rejuvenation of aged mice, suggesting that tissues have inherent capabilities to regenerate, and circulating factors may be promoting/inhibiting this .
Specifically; supplementation of GDF11 (growth and differentiation factor 11) can reverse some effects of ageing (muscle tissue rejuvenates, and some degree of cognitive improvements) ; conversely circulating CCL11 impairs neurogenesis in aged mice and causes cognitive impairment . GDF11 decreases with age, CCL11 increases with age.
(Image from Bitto et al 2014, )
These factors (well, GDF11 at least) are not as highly expressed in humans as in mice , so the specific mechanisms may differ.
What other circulating factors been shown to affect health or longevity? Particularly in humans, but other mouse (or 'higher' organisms, e.g. primates) experiments would be interesting too.
- Bitto, A., and Kaeberlein, M., “Rejuvenation: it’s in our blood.,” Cell Metab., vol. 20, no. 1, pp. 2–4, Jul. 2014.
- Sinha, M., et al, “Restoring systemic GDF11 levels reverses age-related dysfunction in mouse skeletal muscle.,” Science, vol. 344, no. 6184, pp. 649–52, May 2014.
- Villeda, S., et al, “The ageing systemic milieu negatively regulates neurogenesis and cognitive function.,” Nature, vol. 477, no. 7362, pp. 90–4, Sep. 2011.
- Souza, T., et al, “Proteomic identification and functional validation of activins and bone morphogenetic protein 11 as candidate novel muscle mass regulators.,” Mol. Endocrinol., vol. 22, no. 12, pp. 2689–702, Dec. 2008.