Three-dimensional cellular development is essential for ex vivo formation of human bone

Nat Biotechnol. 2000 Sep;18(9):954-8. doi: 10.1038/79439.


Tissue engineering of human bone is a complex process, as the functional development of bone cells requires that regulatory signals be temporally and spatially ordered. The role of three-dimensional cellular interactions is well understood in embryonic osteogenesis, but in vitro correlates are lacking. Here we report that in vitro serum-free transforming growth factor (TGF)-beta1 stimulation of osteogenic cells immediately after passage results in the formation of three-dimensional cellular condensations (bone cell spheroids) within 24 to 48 hours. In turn, bone cell spheroid formation results in the up-regulation of several bone-related proteins (e.g., alkaline phosphatase, type I collagen, osteonectin) during days 3-7, and the concomitant formation of micro-crystalline bone. This system of ex vivo bone formation should provide important information on the physiological, biological and molecular basis of osteogenesis.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alkaline Phosphatase / metabolism
  • Biomedical Engineering / methods*
  • Biotechnology
  • Blotting, Western
  • Bone Development
  • Bone Marrow / metabolism
  • Bone Transplantation*
  • Bone and Bones / cytology*
  • Bone and Bones / physiology*
  • Bone and Bones / ultrastructure
  • Cell Division
  • Cell Line
  • Cells, Cultured
  • Collagen / metabolism
  • Culture Media, Serum-Free / metabolism
  • Flow Cytometry
  • Humans
  • Immunohistochemistry
  • Integrins / metabolism
  • Microscopy, Electron
  • Osteogenesis / physiology
  • Osteonectin / metabolism
  • Regeneration / physiology
  • Spectroscopy, Fourier Transform Infrared
  • Spectrum Analysis, Raman
  • Time Factors
  • Transforming Growth Factor beta / metabolism
  • Transforming Growth Factor beta / therapeutic use
  • Transforming Growth Factor beta1
  • Up-Regulation


  • Culture Media, Serum-Free
  • Integrins
  • Osteonectin
  • TGFB1 protein, human
  • Transforming Growth Factor beta
  • Transforming Growth Factor beta1
  • Collagen
  • Alkaline Phosphatase