title: Validation of an in vitro 3D bone culture model with perfused and mechanically stressed ceramic scaffold.
abstract: An engineered three dimensional (3D) in vitro cell culture system was designed with the goal of inducing and controlling in vitro osteogenesis in a reproducible manner under conditions more similar to the in vivo bone microenvironment than traditional two-dimensional (2D) models. This bioreactor allows efficient mechanical loading and perfusion of an original cubic calcium phosphate bioceramic of highly controlled composition and structure. This bioceramic comprises an internal portion containing homogeneously interconnected macropores surrounded by a dense layer, which minimises fluid flow bypass around the scaffold. This dense and flat layer permits the application of a homogeneous loading on the bioceramic while also enhancing its mechanical strength. Numerical modelling of constraints shows that the system provides direct mechanical stimulation of cells within the scaffold. Experimental results establish that under perfusion at a steady flow of 2 µL/min, corresponding to 3 ≤ Medium velocity ≤ 23 µm/s, mouse calvarial cells grow and differentiate as osteoblasts in a reproducible manner, and lay down a mineralised matrix. Moreover, cells respond to mechanical loading by increasing C-fos expression, which demonstrates the effective mechanical stimulation of the culture within the scaffold. In summary, we provide a "proof-of-concept" for osteoblastic cell culture in a controlled 3D culture system under perfusion and mechanical loading. This model will be a tool to analyse bone cell functions in vivo, and will provide a bench testing system for the clinical assessment of bioactive bone-targeting molecules under load.
authors.affiliation: Centre for Biomedical and Healthcare Engineering, Ecole Nationale Supérieure des Mines, CIS-EMSE, CNRS: UMR 5307, Saint-Etienne, France.marchat@emse.fr.
authors.forename: G
authors.initials: G
authors.lastname: Bouet
authors.forename: M
authors.initials: M
authors.lastname: Cruel
authors.forename: C
authors.initials: C
authors.lastname: Laurent
authors.forename: L
authors.initials: L
authors.lastname: Vico
authors.forename: L
authors.initials: L
authors.lastname: Malaval
authors.forename: D
authors.initials: D
authors.lastname: Marchat
mesh_terms: D000469:Alkaline Phosphatase / Q000235:genetics; D000818:Animals; D019149:Bioreactors; D001842:Bone and Bones / Q000166:cytology* / Q000378:metabolism; D002130:Calcium Phosphates / Q000737:chemistry; D018929:Cell Culture Techniques / Q000295:instrumentation / Q000379:methods*; D002454:Cell Differentiation / Q000235:genetics; D002478:Cells, Cultured; D002516:Ceramics / Q000737:chemistry*; D024042:Collagen Type I / Q000235:genetics; D015870:Gene Expression; D051379:Mice; D008855:Microscopy, Electron, Scanning; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism; D010012:Osteogenesis / Q000235:genetics; D053495:Osteopontin / Q000235:genetics; D010477:Perfusion; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000076182:Sp7 Transcription Factor; D013314:Stress, Mechanical; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry*; D014157:Transcription Factors / Q000235:genetics; D014961:X-Ray Diffraction
chemical_list: D002130:Calcium Phosphates; D024042:Collagen Type I; D000076182:Sp7 Transcription Factor; C479466:Sp7 protein, mouse; D014157:Transcription Factors; D053495:Osteopontin; C020243:calcium phosphate; D000469:Alkaline Phosphatase