title: Transforming growth factor-beta1 incorporated during setting in calcium phosphate cement stimulates bone cell differentiation in vitro.
abstract: Growth stimulation of periimplant tissues by growth factors like transforming growth factor-beta1 (TGF-beta1) may increase the indication for and success of implant use. Calcium phosphate as a material for implants or for coating of implants is known for its good biologic interaction with bone. Therefore, calcium phosphate implants combined with TGF-beta1 might improve osseointegration. In this study we hypothesise that the addition of recombinant human TGF-beta1 (rhTGF-beta1) to calcium phosphate cement (CPC) affects the differentiation of bone cells growing on the cement layer. rhTGF-beta1 incorporated during setting in a CPC layer at 20 ng rhTGF-beta1/60 mg cement was found to be gradually released into tissue culturing medium leading to a 20% release after 24 h. Two cell populations were obtained from collagenase-treated fragments of adult rat long bones: preosteoblastic cells, which were released by the collagenase treatment, and osteoblastic cells, which grew from the collagenase-stripped bone fragments. Both cell populations were tested for their osteoblastic characteristic phenotype by measuring their alkaline phosphatase (ALP) activity after vitamin D treatment and cyclic AMP after parathyroid hormone stimulation. After preculture the cells were plated on a layer of CPC containing 0 (control), 10, or 20 ng rhTGF-beta1/60 mg CPC. Bone cell differentiation was analyzed after 10 days by measuring the ALP activity, as well as the protein content of the cell layer. Incorporation of rhTGF-beta1 in the CPC did not change the ALP activity in osteoblastic cells, but a significant (analyzed by multivariate analysis of variance) increase was observed in preosteoblastic cells. Incorporation of 10 ng of rhTGF-beta1 in 60 mg of CPC increased the ALP activity in preosteoblastic cells by threefold and 20 ng rhTGF-beta1/60 mg CPC increased it by fivefold. The total protein content was not affected by rhTGF-beta1 in either of the cell populations. We conclude that rhTGF-beta1 incorporated during setting in CPC stimulates the differentiation of preosteoblastic cells in vitro. These results provide a basis for further studies on the use of this combination as an implant material in vivo.
authors.affiliation: Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam-Vrije Universiteit, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands.e.blom.ocb.acta@med.vu.nl
authors.forename: E J
authors.initials: EJ
authors.lastname: Blom
authors.forename: J
authors.initials: J
authors.lastname: Klein-Nulend
authors.forename: C P
authors.initials: CP
authors.lastname: Klein
authors.forename: K
authors.initials: K
authors.lastname: Kurashina
authors.forename: M A
authors.initials: MA
authors.lastname: van Waas
authors.forename: E H
authors.initials: EH
authors.lastname: Burger
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000469:Alkaline Phosphatase / Q000032:analysis; D000818:Animals; D015415:Biomarkers; D001843:Bone Cements; D001861:Bone Regeneration; D001842:Bone and Bones / Q000166:cytology*; D002117:Calcitriol / Q000494:pharmacology; D002130:Calcium Phosphates; D002454:Cell Differentiation; D002478:Cells, Cultured; D006801:Humans; D010006:Osteoblasts / Q000166:cytology* / Q000187:drug effects; D010281:Parathyroid Hormone / Q000494:pharmacology; D051381:Rats; D011994:Recombinant Proteins / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
chemical_list: D015415:Biomarkers; D001843:Bone Cements; D002130:Calcium Phosphates; D010281:Parathyroid Hormone; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; D000469:Alkaline Phosphatase; D002117:Calcitriol; D015056:1-Methyl-3-isobutylxanthine