title: Bone formation in CaP-coated and noncoated titanium fiber mesh.
abstract: The osteogenic activity of calcium phosphate (CaP)-coated and noncoated porous titanium (Ti) fiber mesh loaded with cultured syngeneic osteogenic cells after prolonged in situ culturing was compared in a syngeneic rat ectopic assay model. Rat bone marrow (RBM) cells were loaded onto the CaP-coated and noncoated Ti scaffolds using either a droplet or a suspension loading method. After loading, the RBM cells were cultured for 8 days in vitro. Thereafter, implants were subcutaneously placed in 39 syngeneic rats. The rats were euthanized and the implants retrieved at 2, 4, and 8 weeks postoperatively. Further, in the 8 week group fluorochrome bone markers were injected at 2, 4, and 6 weeks. Histological analysis demonstrated that only the CaP-coated meshes supported bone formation. The amount of newly formed bone varied between single and multiple spheres to filling a significant part of the mesh porosity. In the newly formed bone, osteocytes embedded in a mineralized matrix could be observed clearly. On the other hand, in the noncoated titanium implants, abundant deposition of calcium-containing material was seen. This deposit lacked a bonelike tissue organization. Further analysis revealed that the cell-loading method did not influence the final amount of bone formation. In CaP-coated implants the accumulation sequence of the fluorochrome markers showed that bone formation started on the mesh fibers. In conclusion, our results prove that the combination of a thin CaP coating, Ti-mesh, and RBM cells can indeed generate ectopic bone formation after prolonged in vitro culturing. No effect of the loading method was observed on the final amount of bone.
authors.affiliation: Biomaterials, College of Dental Science, University Medical Center Nijmegen, Nijmegen, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands.
authors.forename: J W M
authors.initials: JW
authors.lastname: Vehof
authors.forename: J
authors.initials: J
authors.lastname: van den Dolder
authors.forename: J E
authors.initials: JE
authors.lastname: de Ruijter
authors.forename: P H M
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 / Q000378:metabolism; D002118:Calcium / Q000032:analysis; D002130:Calcium Phosphates; D002478:Cells, Cultured; D020099:Coated Materials, Biocompatible; D020007:Implants, Experimental; D008297:Male; D008856:Microscopy, Fluorescence; D016348:Osseointegration; D010012:Osteogenesis / Q000502:physiology*; D016062:Porosity; D051381:Rats; D011916:Rats, Inbred F344; D014025:Titanium
chemical_list: D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; C101914:titanium fiber; D014025:Titanium; D002118:Calcium