title: In vitro mesenchymal stem cell differentiation after mechanical stimulation.
abstract: OBJECTIVE
  Mesenchymal stem cells (MSC) are multipotent cells capable of differentiating into adipocytic, chondrocytic and osteocytic lineages on suitable stimulation. We have hypothesized that mechanical loading may influence MSC differentiation and alter their phenotype accordingly.
  
  
  METHODS
  Mouse bone marrow-derived MSC were established in vitro by differential adherence to plastic culture plates and grown in low glucose medium with 10% foetal calf serum and growth factors. Cells grew out and were subcultured up to 20 times. Differentiation protocols were followed for several cell lineages. Clones with trilineage potential were seeded in type I collagen gels and incubated in a tensioning force bioreactor and real-time cell-derived forces were recorded. Gels were fixed and sectioned for light and electron microscopy.
  
  
  RESULTS
  Cell monolayers of parent and cloned mouse bone marrow-derived MSC differentiated into adipocytes, osteocytes and chondrocytes, but not into cardiomyocytes, myotubes or neuronal cells. When cast into type I collagen gels and placed in tensioning bioreactors, MSC differentiated into fibroblast-like cells typical of tissue stroma, and upregulated α-smooth muscle actin, but rarely upregulated desmin. Electron microscopy showed collagen and elastin fibre synthesis into the matrix.
  
  
  CONCLUSIONS
  These experiments confirmed that MSC cell fate choice depends on minute, cell-derived forces. Applied force could assist in commercial manufacture of cultured bio-engineered prostheses for regenerative medicine as it mimics tissue stresses and constitutes a good model for development of tissue substitutes.
authors.affiliation: Department of Biomedical Science, University of Westminster, London, UK.
authors.forename: C E
authors.initials: CE
authors.lastname: Sarraf
authors.forename: W R
authors.initials: WR
authors.lastname: Otto
authors.forename: M
authors.initials: M
authors.lastname: Eastwood
mesh_terms: D017667:Adipocytes / Q000166:cytology / Q000378:metabolism; D000818:Animals; D001696:Biomechanical Phenomena; D002454:Cell Differentiation / Q000502:physiology*; D019070:Cell Lineage; D002468:Cell Physiological Phenomena / Q000502:physiology*; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000378:metabolism; D003094:Collagen / Q000378:metabolism / Q000648:ultrastructure; D024042:Collagen Type I / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism / Q000648:ultrastructure; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism / Q000648:ultrastructure; D051379:Mice; D008810:Mice, Inbred C57BL; D039902:Multipotent Stem Cells / Q000378:metabolism; D010011:Osteocytes / Q000166:cytology / Q000378:metabolism; D010812:Physical Stimulation
chemical_list: D024042:Collagen Type I; D003094:Collagen