title: Human endothelial-like differentiated precursor cells maintain their endothelial characteristics when cocultured with mesenchymal stem cell and seeded onto human cancellous bone.
abstract: BACKGROUND
  Cancellous bone is frequently used for filling bone defects in a clinical setting. It provides favourable conditions for regenerative cells such as MSC and early EPC. The combination of MSC and EPC results in superior bone healing in experimental bone healing models.
  
  
  METHODS
  We investigated the influence of osteogenic culture conditions on the endothelial properties of early EPC and the osteogenic properties of MSC when cocultured on cancellous bone. Additionally, cell adhesion, metabolic activity, and differentiation were assessed 2, 6, and 10 days after seeding.
  
  
  RESULTS
  The number of adhering EPC and MSC decreased over time; however the cells remained metabolically active over the 10-day measurement period. In spite of a decline of lineage specific markers, cells maintained their differentiation to a reduced level. Osteogenic stimulation of EPC caused a decline but not abolishment of endothelial characteristics and did not induce osteogenic gene expression. Osteogenic stimulation of MSC significantly increased their metabolic activity whereas collagen-1α and alkaline phosphatase gene expressions declined. When cocultured with EPC, MSC's collagen-1α gene expression increased significantly.
  
  
  CONCLUSIONS
  EPC and MSC can be cocultured in vitro on cancellous bone under osteogenic conditions, and coculturing EPC with MSC stabilizes the latter's collagen-1α gene expression.
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany. d.henrich@trauma.uni-frankfurt.de
authors.forename: Dirk
authors.initials: D
authors.lastname: Henrich
authors.forename: Kerstin
authors.initials: K
authors.lastname: Wilhelm
authors.forename: Joerg
authors.initials: J
authors.lastname: Warzecha
authors.forename: Johannes
authors.initials: J
authors.lastname: Frank
authors.forename: John
authors.initials: J
authors.lastname: Barker
authors.forename: Ingo
authors.initials: I
authors.lastname: Marzi
authors.forename: Caroline
authors.initials: C
authors.lastname: Seebach
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D001859:Bone Neoplasms / Q000628:therapy; D001842:Bone and Bones / Q000166:cytology* / Q000473:pathology*; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology* / Q000502:physiology; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000502:physiology; D010012:Osteogenesis / Q000235:genetics / Q000502:physiology
chemical_list: D000469:Alkaline Phosphatase