Authors: Henry E. Young, Henson NL, Black GF, Hawkins KC, Coleman JA, Black AC Jr
Endogenous naturally-occurring totipotent stem cells and pluripotent stem cells have been isolated from the skeletal muscle of adult mammals, including humans. This study was undertaken to determine their particular location within adult rat skeletal muscle and to verify the identity of the stained cells. Adult rats were euthanized following the guidelines of Mercer University’s IACUC. Skeletal muscle was harvested and processed for immunocytochemistry. Cells were stained with carcinoembryonic antigen-cell adhesion molecule-1 (CEA-CAM-1) and stage-specific embryonic antigen-4 (SSEA-4). Positive and negative staining controls were run to verify the validity of the immunostaining. CEA-CAM-1+ cells were located preferentially within vascular connective tissues, whereas SSEA-4+ cells were located preferentially within neuronal connective tissues. CEA-CAM-1+ stem cells and SSEA-4+ cells were isolated from adult rat skeletal muscle, segregated, cloned from single cells, and their unique morphologies, differentiation potentials, and attributes in culture were subsequently characterized. Four populations of stem cells were identified that share the CEA-CAM-1 and/or SSEA-4 epitopes. Totipotent stem cells and transitional-totipotent stem cell/pluripotent stem cells share the CEA-CAM-1 epitope, whereas the transitionaltotipotent stem cell/pluripotent stem cells, pluripotent stem cells, and transitional- pluripotent stem cell/germ layer lineage stem cells share the SSEA-4 epitope. This report describes native populations of endogenous naturallyoccurring totipotent stem cells and pluripotent stem cells in adult rat skeletal muscle. Studies are ongoing to address their functional significance during normal tissue maintenance and repair of body organs.
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