title: Osteostatin improves the osteogenic activity of fibroblast growth factor-2 immobilized in Si-doped hydroxyapatite in osteoblastic cells.
abstract: Si-doped hydroxyapatite (Si-HA) is a suitable ceramic for the controlled release of agents to improve bone repair. We recently showed that parathyroid hormone-related protein (PTHrP) (107-111) (osteostatin) has remarkable osteogenic features in various in vitro and in vivo systems. Fibroblast growth factor (FGF)-2 modulates osteoblastic function and induces angiogenesis, and can promote osteoblast adhesion and proliferation after immobilization on Si-HA. In the present study we examined whether osteostatin might improve the biological efficacy of FGF-2-coated Si-HA in osteoblastic MC3T3-E1 cells in vitro. We found that Si-HA/FGF-2 in the presence or absence of osteostatin (100 nM) similarly increased cell growth (by about 50%). However, addition of the latter peptide to Si-HA/FGF-2 significantly enhanced gene expression of Runx2, osteocalcin, vascular endothelial growth factor (VEGF) and the VEGF receptors 1 and 2, without significantly affecting that of FGF receptors in these cells. Moreover, secreted VEGF in the MC3T3-E1 cell conditioned medium, which induced the proliferation of pig endothelial-like cells, was also enhanced by these combined factors. The synergistic action of osteostatin and Si-HA/FGF-2 on the VEGF system was abrogated by a mitogen-activated protein kinase inhibitor (U0126) and by the calcium antagonist verapamil. This action was related to an enhancement of alkaline phosphatase activity and matrix mineralization in MC3T3-E1 cells, and also in primary human osteoblastic cells. These in vitro data show that osteostatin increases the osteogenic efficacy of a Si-HA/FGF-2 biomaterial by a mechanism involving mitogen-activated protein kinases and intracellular Ca(2+). These findings provide an attractive strategy for bone tissue engineering.
authors.affiliation: Laboratorio de Metabolismo Mineral y Óseo, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz, Madrid, Spain. dlozano@fjd.es
authors.forename: Daniel
authors.initials: D
authors.lastname: Lozano
authors.forename: María José
authors.initials: MJ
authors.lastname: Feito
authors.forename: Sergio
authors.initials: S
authors.lastname: Portal-Núñez
authors.forename: Rosa María
authors.initials: RM
authors.lastname: Lozano
authors.forename: María Concepción
authors.initials: MC
authors.lastname: Matesanz
authors.forename: María Concepción
authors.initials: MC
authors.lastname: Serrano
authors.forename: María
authors.initials: M
authors.lastname: Vallet-Regí
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Portolés
authors.forename: Pedro
authors.initials: P
authors.lastname: Esbrit
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D057134:Antibodies, Neutralizing / Q000494:pharmacology; D001672:Biocompatible Materials / Q000494:pharmacology; D002113:Calcification, Physiologic / Q000187:drug effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D017077:Culture Media, Conditioned / Q000494:pharmacology; D017886:Durapatite / Q000494:pharmacology*; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D055767:Immobilized Proteins / Q000494:pharmacology*; D051379:Mice; D010006:Osteoblasts / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D010012:Osteogenesis / Q000187:drug effects*; D044162:Parathyroid Hormone-Related Protein / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology*; D034421:Sus scrofa; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000235:genetics / Q000378:metabolism; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics / Q000378:metabolism
chemical_list: D057134:Antibodies, Neutralizing; D001672:Biocompatible Materials; D017077:Culture Media, Conditioned; D055767:Immobilized Proteins; D044162:Parathyroid Hormone-Related Protein; D010446:Peptide Fragments; D042461:Vascular Endothelial Growth Factor A; C071784:parathyroid hormone-related protein (107-111); D016222:Fibroblast Growth Factor 2; D017886:Durapatite; D040281:Vascular Endothelial Growth Factor Receptor-1; D040301:Vascular Endothelial Growth Factor Receptor-2; D000469:Alkaline Phosphatase