title: Biological activity of recombinant human growth factors released from biocompatible bone implants.
abstract: The present investigation was performed to study the bioactivity of osteoinductive and osteoproliferative growth factors after release from biocompatible bone implants. Three types of porous carriers were used in this study: hydroxyapatite, alpha tricalcium phosphate, and a neutralized glass ceramic. Implants were loaded with recombinant human bone morphogenetic protein 2 (rh-BMP-2) and recombinant human basic fibroblast growth factor (rh-bFGF) in a concentration of 2 microg/150 microL PBS each. The released growth factors were then applicated into SAOS-2-cell cultures. After 3, 5, and 7 days cell differentiation was measured by the activity of alkaline phosphatase (ALP), cell proliferation by using a MTT assay as well as a cell counter. Rh-BMP-2 released during the first hour from the scaffolds led to a significant increase of the activity of ALP in the incubated SAOS-2-cell culture after 3, 5, and 7 days. However, the incubation with rh-BMP-2 released after 24 h was not found to increase the expression of ALP. The incubation of cell cultures with rh-bFGF released during the first hour led to a significant increase of cell number and of extinction in the MTT assay, whereas this increase was not observed after incubation with rh-bFGF released after 24 h. The in vitro measured biological activity of released growth factors from the surface of synthetic implants is time-depending. If prolonged osteoinductive and osteoproliferative potency of growth factors is desired, a modified application technique should be chosen to stabilize those proteins.
authors.affiliation: Department of Orthopaedic Surgery, University Hospital Carl Gustav Carus Dresden, Medical Faculty, Technical University of Dresden, Germany. joerg.ziegler@uniklinikum-dresden.de
authors.forename: Joerg
authors.initials: J
authors.lastname: Ziegler
authors.forename: Dominique
authors.initials: D
authors.lastname: Anger
authors.forename: Frank
authors.initials: F
authors.lastname: Krummenauer
authors.forename: Dieter
authors.initials: D
authors.lastname: Breitig
authors.forename: Stefan
authors.initials: S
authors.lastname: Fickert
authors.forename: Klaus-Peter
authors.initials: KP
authors.lastname: Guenther
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D001672:Biocompatible Materials / Q000737:chemistry*; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D018786:Bone Substitutes / Q000737:chemistry; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D007700:Kinetics; D019736:Prostheses and Implants; D011994:Recombinant Proteins / Q000737:chemistry* / Q000378:metabolism; D013778:Tetrazolium Salts / Q000494:pharmacology; D013844:Thiazoles / Q000494:pharmacology; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000378:metabolism
chemical_list: D001672:Biocompatible Materials; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D018786:Bone Substitutes; D036341:Intercellular Signaling Peptides and Proteins; D011994:Recombinant Proteins; D013778:Tetrazolium Salts; D013844:Thiazoles; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2; D016222:Fibroblast Growth Factor 2; D000469:Alkaline Phosphatase; C022616:thiazolyl blue