Muscle cell injuries (red) up-regulate Delta (green) in young mice (left), but not in old mice (right).

Rando/AAAS

As we age, it seems to be increasingly difficult to recover from injuries. According to research from Irina Conboy, Thomas Rando, and colleagues (Stanford University and the Palo Alto VA Medical Center, Palo Alto, CA), part of the blame for this age-related decline belongs to lazy stem cells that sit idly by rather than repair injuries.

Normally, injuries to muscle tissue activate the stem cell-like satellite cells, which then multiply and differentiate into myoblasts that can fuse with and thus repair injured muscle fibers. The injury-induced proliferation is a function of the Notch pathway. But Rando's group shows that satellite cells in older animals are unable to activate Notch and so do not repair injured muscle.

Notch gets inactivated because aged muscle cells do not up-regulate Delta,...

The Rockefeller University Press
2003
The Rockefeller University Press
2003
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