Scientists have found and manipulated body chemistry linked to the aging of muscles, and were able to restore the ability of old human muscle to repair and rebuild itself.
Importantly, the research also found evidence that aging muscles need to be kept in shape, because long periods of atrophy are more challenging to overcome. Older muscles do not respond as well to sudden bouts of exercise. And rather than building muscle, older people can instead generate scar tissue if they exercise after long periods of inactivity.
Previous studies have shown that adult muscle stem cells have a receptor called Notch, which triggers growth when activated. An enzyme called mitogen-activated protein kinase (MAPK) regulates Notch activity.
In the lab, the researchers cultured old human muscle and forced the activation of MAPK. The regenerative ability of the old muscle was significantly enhanced.
Sources:
EMBO Molecular Medicine September 30, 2009 [Epub ahead of Print]