title: Morphology of in vitro expanded human muscle-derived stem cells.
abstract: BACKGROUND
  Skeletal muscle contains populations of multipotent adult stem cells also referred to as muscle-derived stem cells.
  
  
  OBJECTIVE
  The main goal of this study was to isolate and culture human adult stem cells from skeletal muscle and characterize them.
  
  
  METHODS
  Muscle-derived stem cells were isolated from biopsy specimens of femoral muscle. The cells were cultured in Dulbecco's modified Eagle's minimal essential medium supplemented with 10% fetal calf serum and gentamycin. When they reached confluence, they were sub-passaged up to the third passage. Cells from the last passage were prepared for TEM analysis. Production of alpha-actin and desmin was confirmed by histochemistry. Moreover, the phenotypic characterization was performed.
  
  
  RESULTS
  Primary isolated muscle-derived stem cells had a fibroblast-like shape. During subsequent passages they maintained this morphology. TEM analysis showed typical ultrastructural morphology of mesenchymal stem cells. They had large pale nuclei with a large amount of euchromatine. Nuclei were irregular with noticeable nucleoli. Dilated cisterns of rough endoplasmic reticulum were present in cytoplasm. In certain parts of the cytoplasm there were aggregates of granules of glycogen. The products of cells were actively secreted into the extracellular matrix. They expressed alpha-actin and desmin. The results of phenotypic characterization showed that almost all analyzed cells were CD13, CD34, CD56 positive and CD45 negative. Moreover, they did not express anti-human fibroblast surface protein.
  
  
  CONCLUSIONS
  Muscle-derived stem cells exhibited typical characteristics typical for mesenchymal stem cells. After analysis of their differentiation potential they could be used in tissue engineering and regenerative medicine.
authors.affiliation: Institute of Medical Biology and Genetics, Faculty of Medicine, Comenius University in Bratislava, Sasinkova 4, Bratislava, Slovak Republic. lubos.danisovic@fmed.uniba.sk
authors.forename: Lubos
authors.initials: L
authors.lastname: Danisovic
authors.forename: Ivan
authors.initials: I
authors.lastname: Varga
authors.forename: Stefan
authors.initials: S
authors.lastname: Polak
authors.forename: Marcela
authors.initials: M
authors.lastname: Ulicna
authors.forename: Daniel
authors.initials: D
authors.lastname: Bohmer
authors.forename: Jan
authors.initials: J
authors.lastname: Vojtassak
mesh_terms: D000328:Adult; D015703:Antigens, CD / Q000032:analysis; D002478:Cells, Cultured; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology; D039902:Multipotent Stem Cells / Q000166:cytology* / Q000276:immunology; D018485:Muscle Fibers, Skeletal / Q000166:cytology*; D032496:Satellite Cells, Skeletal Muscle / Q000166:cytology
chemical_list: D015703:Antigens, CD