title: Evaluation of the effect of three calcium phosphate powders on osteoblast cells.
abstract: The aim of the present study was to assess the effect of three calcium phosphate powders entering in the composition of bone substitute materials on osteoblast-cells activity. These powders were hydroxyapatite (HA) widely used as a biomaterial, nanocrystalline carbonate apatite (C A) very close to bone mineral crystals, and an experimental one: calcium phosphate cement-1 (CPC-1) composed of an amorphous Ca-P phase and brushite. The powders were physico-chemically characterized. The very reactive CPC-1 powder became transformed in cell culture medium: recrystallization of amorphous precursors and hydrolysis of brushite into poorly crystalline apatite occurred. Osteoblast-cells activity was evaluated: for low level of calcium phosphates (>100 microg/ml) CPC-1 enhanced proliferation and, to a lesser degree, differentiation on alkaline phosphatase activity. For 100 microg/ml of powders we observed a great alteration of biological activity of the osteoblasts: evaluation of proliferation indicated an inhibition for all samples, and a decrease of two differentiation markers: alkaline phosphatase activity and osteocalcin release were noticed, suggesting a down regulation due to the presence of large amount of mineral powder.
authors.affiliation: Laboratoire de Cytophysiologie des cellules eucaryotes, JE 1962, 38 rue des 36 Ponts, 31400 Toulouse, France. jvmidy@ijonie
authors.forename: V
authors.initials: V
authors.lastname: Midy
authors.forename: M
authors.initials: M
authors.lastname: Dard
authors.forename: E
authors.initials: E
authors.lastname: Hollande