title: Shear stress induces osteogenic differentiation of human mesenchymal stem cells.
abstract: OBJECTIVE
  To determine whether fluid flow-induced shear stress affects the differentiation of bone marrow-derived human mesenchymal stem cells (hMSCs) into osteogenic cells.
  
  
  METHODS
  hMSCs cultured with or without osteogenic differentiation medium were exposed to fluid flow-induced shear stress and analyzed for alkaline phosphatase activity and expression of osteogenic genes.
  
  
  RESULTS
  Immediately following shear stress, alkaline phosphatase activity in osteogenic medium was significantly increased. At days 4 and 8 of culture the mRNA expression of bone morphogenetic protein-2 and osteopontin was significantly higher in hMSCs subjected to shear stress than those cultured in static conditions. However, hMSCs cultured in osteogenic differentiation medium were less responsive in gene expression of alkaline phosphatase and bone morphogenetic protein-2.
  
  
  CONCLUSIONS
  These data demonstrate that shear stress stimulates hMSCs towards an osteoblastic phenotype in the absence of chemical induction, suggesting that certain mechanical stresses may serve as an alternative to chemical stimulation of stem cell differentiation.
authors.affiliation: Department of Physiology & Biophysics, University of Illinois at Chicago, Chicago, IL 60612, USA.
authors.forename: Gregory
authors.initials: G
authors.lastname: Yourek
authors.forename: Susan M
authors.initials: SM
authors.lastname: McCormick
authors.forename: Jeremy J
authors.initials: JJ
authors.lastname: Mao
authors.forename: Gwendolen C
authors.initials: GC
authors.lastname: Reilly
mesh_terms: D000469:Alkaline Phosphatase / Q000032:analysis; D055396:Bone Morphogenetic Protein 2 / Q000235:genetics; D018929:Cell Culture Techniques; D002454:Cell Differentiation; D003470:Culture Media; D006801:Humans; D007700:Kinetics; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D010006:Osteoblasts / Q000166:cytology; D010012:Osteogenesis; D053495:Osteopontin / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D012212:Rheology; D013314:Stress, Mechanical
chemical_list: D055396:Bone Morphogenetic Protein 2; D003470:Culture Media; D012333:RNA, Messenger; D053495:Osteopontin; D000469:Alkaline Phosphatase