title: Three-dimensional cellular development is essential for ex vivo formation of human bone.
abstract: 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.
authors.affiliation: Department of Pediatrics, University of Michigan, Ann Arbor 48109, USA.
authors.forename: S
authors.initials: S
authors.lastname: Kale
authors.forename: S
authors.initials: S
authors.lastname: Biermann
authors.forename: C
authors.initials: C
authors.lastname: Edwards
authors.forename: C
authors.initials: C
authors.lastname: Tarnowski
authors.forename: M
authors.initials: M
authors.lastname: Morris
authors.forename: M W
authors.initials: MW
authors.lastname: Long
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D001698:Biomedical Engineering / Q000379:methods*; D001709:Biotechnology; D015153:Blotting, Western; D001846:Bone Development; D001853:Bone Marrow / Q000378:metabolism; D016025:Bone Transplantation; D001842:Bone and Bones / Q000166:cytology* / Q000502:physiology* / Q000648:ultrastructure; D002455:Cell Division; D002460:Cell Line; D002478:Cells, Cultured; D003094:Collagen / Q000378:metabolism; D016895:Culture Media, Serum-Free / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D016023:Integrins / Q000378:metabolism; D008854:Microscopy, Electron; D010012:Osteogenesis / Q000502:physiology; D015676:Osteonectin / Q000378:metabolism; D012038:Regeneration / Q000502:physiology; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000378:metabolism / Q000627:therapeutic use; D053773:Transforming Growth Factor beta1; D015854:Up-Regulation
chemical_list: D016895:Culture Media, Serum-Free; D016023:Integrins; D015676:Osteonectin; C508960:TGFB1 protein, human; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D003094:Collagen; D000469:Alkaline Phosphatase