Harnessing the potential of myogenic satellite cells
Sherwood RI, Wagers AJ
Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
Adult skeletal muscle has remarkable regenerative potential, which is mainly attributable to a small population of undifferentiated skeletal muscle precursors called satellite cells. These cells reside underneath the basal lamina of skeletal myofibers and can be activated to proliferate, differentiate and fuse to form new muscle tissue. Satellite cells have long been considered promising mediators of therapeutic muscle regeneration. However, in proactive, the regenerative function of such cells, which in many cases have been derived or expanded by ex vivo cultures, can be surprisingly low. A recent study from Montarras and colleagues has provided new insights into the requirements for efficient muscle engraftment from purified muscle satellite cells, suggesting possible strategies to enhance their therapeutic potential.
Satellite cell numbers in young and older men 24 hours after eccentric exercise.
Dreyer HC, Blanco CE, Sattler FR, Schroeder ET, Wiswell RA.
Department of Biokinesiology and physical therapy, University of Southern California, Los Angeles, USA.
We tested the hypothesis that the expansion of satellite cell numbers, 24 hrs after maximal eccentric knee extensor exercise, is blunted in older men,. Muscle biopsies were obtained from the vastus lateralis of 10 young (23-35 years) and 9 older (60-75 years) men. Satellite cells were identified immunohistorchemically, using an antibody to neutral cell adhesion molecule. After 92 maximal eccentric contractions, the mean number of satellite cells per muscle fiber increased to a greater extent amount the young men (141%; P<0.001) than older men (51%; P=0.002) from pre-exercise levels. Similar results were obtained when satellite cells were expressed as a proportion of all sublaminar nuclei. We conclude that a single bout of maximal eccentric exercise increases satellite cell numbers in both age groups, with a significantly greater response among the young men. These data suggest that age related changes in satellite cell recruitment may contribute to muscle regeneration deficits among the elderly.