Satellite cells, the primary stem cells of adult skeletal muscle

Engineered muscle regeneration has the potential to be one out of the first successful applications of regenerative medicine: muscle is not a too complicated issue with a few type of cells, and the human demand for regeneration is big concerning the muscle centered sports. I am working on an article concerning our lab’s experiments on skeletal muscle regeneration, so the next text is a little intro from an early draft on satellite cells.
Skeletal muscle has a specific multinucleated, syncytial structure in vertebrates. Satellite cells were identified through electron microscopic studies by their specific anatomical position situated between the basal lamina and cell membranes of mature myofibers, and their periferial position earned it the name ’satellite’ cell. Satellite cells are primarily in a quiscent state, dividing very infrequently under normal conditions in the adult. These cells are thought to be the primary stem cells of postnatal skeletal muscle {reviewed in Wagers and Conboy, and Dhawan and Rando} as the source of myogenic cells for growth and repair. Cells in the satellite cell compartment are heterogeneous by origin and function, no single marker exists, and intrinsic differences have been found in differentiation, proliferation and fusogenic capacity.
The classic model of satellite cell self-renewal and the importance of satellite cells in muscle maintenance and repair have been challenged during the past few years as bone marrow-derived cells, and various intramuscular populations were shown to be able to contribute myonuclei and occupy the satellite cell niche. Welcome to the muscle regeneration battlefield! I’ll talk about the bone-marrow challenge later…