title: Conditioned medium from fresh and demineralized bone enhances osteoclastogenesis in murine bone marrow cultures.
abstract: OBJECTIVE
  Osteoclasts rapidly form on the surface of bone chips at augmentation sites. The underlying molecular mechanism, however, is unclear. Soluble factors released from bone chips in vitro have a robust impact on mesenchymal cell differentiation. Whether these soluble factors change the differentiation of hematopoietic cells into osteoclasts remains unknown.
  
  
  METHODS
  Osteoclastogenesis, the formation of tartrate-resistant acid phosphatase-positive multinucleated cells, was studied with murine bone marrow cultures exposed to RANKL and M-CSF, and conditioned medium from fresh (BCM) and demineralized bone matrix (DCM). Histochemical staining, gene and protein expression, as well as viability assays were performed.
  
  
  RESULTS
  This study shows that BCM had no impact on osteoclastogenesis. However, when BCM was heated to 85°C (BCMh), the number of tartrate-resistant acid phosphatase-positive multinucleated cells that developed in the presence of RANKL and M-CSF approximately doubled. In line with the histochemical observations, there was a trend that BCMh increased expression of osteoclast marker genes, in particular the transcription factor c-fos. The expression of c-fos was significantly reduced by the TGF-β receptor I antagonist SB431542. DCM significantly stimulated osteoclastogenesis, independent of thermal processing.
  
  
  CONCLUSIONS
  These data demonstrate that activated BCM by heat and DBM are able to stimulate osteoclastogenesis in vitro. These in vitro results support the notion that the resorption of autografts may be supported by as yet less defined paracrine mechanisms.
authors.affiliation: Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Bern, Switzerland.|Laboratory of Oral Cell Biology, School of Dental Medicine, University of Bern, Bern, Switzerland.|Department of Oral and Maxillofacial Surgery, School of Dental Medicine, Universitat Internacional de Catalunya, Barcelona, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Caballé-Serrano
authors.affiliation: Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Bern, Switzerland.|Laboratory of Oral Cell Biology, School of Dental Medicine, University of Bern, Bern, Switzerland.|Department of Implant Dentistry, School of Dentistry, Universidade Federal de Santa Catarina Florianopolis, Florianópolis, Brazil.
authors.forename: Guenther
authors.initials: G
authors.lastname: Schuldt Filho
authors.affiliation: Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Bern, Switzerland.|Robert K. Schenk Laboratory of Oral Histology, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Dieter D
authors.initials: DD
authors.lastname: Bosshardt
authors.affiliation: Department of Oral and Maxillofacial Surgery, School of Dental Medicine, Universitat Internacional de Catalunya, Barcelona, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Gargallo-Albiol
authors.affiliation: Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Buser
authors.affiliation: Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Bern, Switzerland.|Laboratory of Oral Cell Biology, School of Dental Medicine, University of Bern, Bern, Switzerland.|Department of Oral Biology, Medical University of Vienna, Vienna, Austria.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Gruber
mesh_terms: D000818:Animals; D001549:Benzamides / Q000494:pharmacology; D001854:Bone Marrow Cells / Q000166:cytology*; D001842:Bone and Bones / Q000166:cytology*; D002454:Cell Differentiation; D017077:Culture Media, Conditioned / Q000494:pharmacology*; D004149:Dioxoles / Q000494:pharmacology; D006358:Hot Temperature; D066298:In Vitro Techniques; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D051379:Mice; D010010:Osteoclasts / Q000166:cytology*; D010012:Osteogenesis / Q000187:drug effects*; D053245:RANK Ligand / Q000494:pharmacology; D013552:Swine
chemical_list: C459179:4-(5-benzo(1,3)dioxol-5-yl-4-pyridin-2-yl-1H-imidazol-2-yl)benzamide; D001549:Benzamides; D017077:Culture Media, Conditioned; D004149:Dioxoles; D053245:RANK Ligand; D016173:Macrophage Colony-Stimulating Factor
keywords: TGF-β; allograft; autografts; autologous bone; bone regeneration; bone-conditioned medium; demineralized freeze-dried bone; graft consolidation; osteoclast; paracrine