title: Differential phenotypic characteristics of heterogeneous cell population in the rabbit periosteum.
abstract: BACKGROUND
  Periosteum and periosteum-derived progenitor cells have demonstrated the potential for stimulative applications in repair of various musculoskeletal tissues. It has been found that the periosteum contains mesenchymal progenitor cells that are capable of differentiating into either osteoblasts or chondrocytes, depending on the culture conditions. Anatomically, the periosteum is a heterogeneous multilayered membrane, consisting of an outer fibrous and an inner cambium layer. The present study was designed to elucidate the phenotypic characteristics of fibrous and cambium layer cells in vitro.
  
  
  METHODS
  Using a sequential enzymatic digestion method, fibrous and cambium layer cells were harvested separately from periosteum-bone explants of the proximal tibia of 6-month-old New Zealand White rabbits.
  
  
  RESULTS
  We found that the cells from each layer showed distinct phenotypic characteristics in a primary monolayer culture system. Specifically, the cambium cells demonstrated higher osteogenic characteristics (higher alkaline phosphatase and osteocalcin levels) than the fibrous cells. However, these differences diminished with time in vitro.
  
  
  CONCLUSIONS
  Our findings suggest that the periosteum has phenotypically distinct heterogeneous cell populations. Care must be taken in order to identify and distinguish the intrinsic phenotypes of the heterogeneous periosteum-derived cell types in vitro.
authors.affiliation: Department of Biomedical Engineering, Tulane University, New Orleans, LA, USA. iyoun@duke.edu
authors.forename: Inchan
authors.initials: I
authors.lastname: Youn
authors.forename: Jun-Kyo Francis
authors.initials: JK
authors.lastname: Suh
authors.forename: Eric A
authors.initials: EA
authors.lastname: Nauman
authors.forename: Deryk G
authors.initials: DG
authors.lastname: Jones
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D049109:Cell Proliferation; D059630:Mesenchymal Stem Cells / Q000502:physiology*; D015675:Osteocalcin / Q000096:biosynthesis; D010521:Periosteum / Q000166:cytology*; D010641:Phenotype; D011817:Rabbits
chemical_list: D015675:Osteocalcin