Young extracellular vesicles rejuvenate aged muscle

Exposure to young blood slows down aging of several organs and prevents physical, cognitive and immune decline. However, how circulating factors mediate these effects is poorly understood. In this issue of Nature Aging, Sahu et al.1 describe a key role for circulating extracellular vesicles in regulating skeletal muscle regeneration during aging, through the shuttling of Klotho transcripts.