title: Influence of rhBMP-2 on rat bone marrow stromal cells cultured on titanium fiber mesh.
abstract: Titanium (Ti) fiber mesh is a candidate scaffold material for the creation of bone graft substitutes (BGS). Two densities (3.54 x 10(4) cells/cm(2) [LD or low density] and 3.54 x 10(5) cells/cm(2) [HD or high density]) of rat bone marrow stromal cells were seeded on Ti-fiber mesh discs. Cells were cultured for up to 16 days, 7 days of which the cells were in the presence of various concentrations of rhBMP-2 (0, 10, 100, and 1,000 ng/mL) in order to evaluate osteogenic expression. Scanning electron microscopy (SEM), light microscopy (LM), energy dispersive spectroscopy (EDS), DNA and calcium (Ca) content measurements, and x-ray diffraction (XRD) analysis were performed. SEM and EDS evaluation showed that a confluent layer of cells was present on top of the meshes together with collagen bundles and calcified globular accretions. Light microscopical evaluation showed a densely stained layer in the upper part of the mesh. SEM and Ca content measurement showed that calcification starts at 8 days. In addition, it was demonstrated that DNA content peaked at 8 days. LM, SEM, and Ca content evaluation revealed positive effects of increasing the cell seeding density, the rhBMP-2 concentration and the culture time on mineralization. Increasing the cell seeding density also showed a positive effect on DNA content. No effects of rhBMP-2 concentration were seen on DNA content. Finally, XRD revealed that the deposited matrix contained a precipitate of a stable calcium phosphate phase. We conclude that (1) titanium fiber mesh sustains excellent osteogenic expression in vitro, (2) increasing the cell seeding density has a positive effect on osteogenic expression in titanium mesh in vitro, and (3) in high density specimens, rhBMP-2 concentrations of 100 ng/mL and 1,000 ng/mL stimulate extracellular matrix calcification in a dose-responsive manner.
authors.affiliation: Biomaterials, College of Dental Science, University Medical Center Nijmegen, Nijmegen, The Netherlands.
authors.forename: J W
authors.initials: JW
authors.lastname: Vehof
authors.forename: A E
authors.initials: AE
authors.lastname: de Ruijter
authors.forename: P H
authors.initials: PH
authors.lastname: Spauwen
authors.forename: J A
authors.initials: JA
authors.lastname: Jansen
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology*; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology*; D018786:Bone Substitutes; D001842:Bone and Bones / Q000166:cytology; D002448:Cell Adhesion / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D006801:Humans; D051381:Rats; D011994:Recombinant Proteins / Q000494:pharmacology; D017154:Stromal Cells / Q000166:cytology*; D023822:Tissue Engineering; D014025:Titanium; D016212:Transforming Growth Factor beta
chemical_list: C525718:BMP2 protein, human; C525720:Bmp2 protein, rat; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D018786:Bone Substitutes; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2; D014025:Titanium