Stem Cells in Adult Skeletal Muscle Tissue: More than a Working Hypothesis

It has been assumed that a stem cell derived from adult tissues can give rise only to progeny specific to that tissue type. However, this dogma has been challenged recently by a series of studies that suggest that adult tissue-derived stem cells may have the potential to differentiate into disparate cell types. In adult skeletal muscle, a particular cell type named satellite cells are believed to form a stable, self-renewing pool of stem cells. However, this tissue contains also at least two other types of muscle-derived stem cells: i) a cell population so-called MDSC, which may represent a predecessor of the satellite cell and ii) a novel stem cell population purified as a side population (SP), which possess the ability to differentiate also into hematopoietic cells.