Cellular and Molecular Signatures of Muscle Regeneration: Current Concepts and Controversies in Adult Myogenesis

Abstract

Adult skeletal muscle generates force in a controlled and directed manner through the contraction of highly specialized, postmitotic, multinucleated myofibers. Life-long muscle function relies on maintenance and regeneration of myofibers through a highly regulated process beginning with activation of normally quiescent muscle precursor cells and proceeding with formation of proliferating progenitors that fuse to generate differentiated myofibers. In this review, we describe the historical basis and current evidence for the identification of satellite cells as adult muscle stem cells, critically evaluate contributions of other cells to adult myogenesis, and summarize existing data regarding the origins, genetic markers, and molecular regulation of satellite cells in normal, diseased, and aged muscle.

Evidence of Reduced Muscle Trauma Through a Minimally Invasive Anterolateral Approach by Means of MRI

“…Nevertheless, there are several basic reports in the literature providing strong evidence that muscular regenerative processes take place within the first weeks after injury [8,19,45], and hence, our MR findings are not jeopardized by the followup time of 12 months. Wagers et al report that adult skeletal muscle possesses remarkable regenerative capacity, and that a large number of new myotubes normally are formed in only a few days after acute muscle damage [45]. Järvinen et al described a three-phase regeneration process of 21 days after muscle injury, which either results in normal muscle or fibrous scar tissue [18].…”

Transdetermination: Drosophila imaginal disc cells exhibit stem cell-like potency

“…These cells both self-renew as well as differentiate in order to replace cells lost to normal physiological turnover or injury (e.g. satellite cells in muscle) (Moss & Leblond, 1970Wagers & Conboy, 2005). Therefore, it is important in normal development to stably maintain cell determination.…”

Cancer stem cell definitions and terminology: the devil is in the details

“…This model is based on the observed consistency of the process under homeostatic conditions. Because the changes may span multiple cell divisions, the process may allow separable subtypes of transit-amplifying cells to be distinguished [23][24][25] . Accordingly, normal tissue cells at sequential early stages of differentiation can now often be discriminated with great precision by immuno logical or molecular profiling -much greater than is achievable by morphology.…”