Understanding muscle regenerative decline with aging: new approaches to bring back youthfulness to aged stem cells.

Aging is characterized by the progressive dysfunction of most tissues and organs, which has been linked to the regenerative decline of their resident stem cells over time. Skeletal muscle provides a stark example of this decline. Its stem cells, also called satellite cells, sustain muscle regeneration throughout life, but at advanced age they fail for largely undefined reasons. Here, we discuss current understanding of the molecular processes regulating satellite cell maintenance throughout life and how age-related failure of these processes contributes to muscle aging. We also highlight the emerging field of rejuvenating biology to restore features of youthfulness in satellite cells, with the ultimate goal of slowing down or reversing the age-related decline in muscle regeneration.