Identification and Characterization of Cells with Stem Cell Properties in Normal and Malignant Muscle Cultures

The skeletal muscle is the body’s largest tissue, accounting for about 40% of the total body weight (Biressi et al. 2007). More importantly, it plays critical roles in movement, respiration, stabilization of the skeleton, glucose homeostasis, and thermoregulation. The basic structural and functional units composing the adult skeletal muscle tissue are the muscle fibers, also known as myofibers (Figure1). They are multinucleated, elongated, and membrane-bound cells. Each fiber is surrounded by connective tissue called endomysium. Several fibers are associated to each other to form the fasciculi. A layer of connective tissue called perimysium surrounds each fasciculus. The fasces forming the muscles are surrounded by a last connective tissue called epimysium. Finally blood vessels and nerves wander the muscle fibers. Myofibers translate the neural pulse into contraction through the motoneuron innervation. Thus, myofibers form highly specialized syncytia site of the muscular contraction