Das, M.M. et al. Commun. Biol. 2, 73 (2019)

Ageing induces changes in the brain that affect cognition; age-related diseases can accelerate the rate of neuronal dysfunction and lead to cognitive decline. Surgically connecting the circulatory system of a young mouse to an old mouse (heterochronic parabiosis) has been shown to counteract age-related changes in multiple organs of the old mouse; however, it remains unclear which blood components and mechanisms are responsible for this rejuvenation.

A new study reports that young bone marrow transplantation (BMT) preserved cognitive function in old recipient mice, despite irradiation-induced suppression of neurogenesis before donor cells injection. The investigators showed that young BMT preserved synaptic connections and reduced microglial activation in the hippocampus; these findings support that neurogenesis has a minimal role in the maintenance of hippocampal function—a brain region sensitive to the detrimental effects of ageing—and could have translational applications for targeting ageing- or disease-associated hippocampal dysfunction.