Osteoclastic resorption of calcium phosphates is potentiated in postosteogenic culture conditions

Abstract

Cell-mediated resorption of densely sintered hydroxyapatite (HA1250), tricalcium phosphate (TCP), and 600 degrees or 900 degrees C calcined hydroxyapatite (HA600 and HA900, respectively), was investigated by using two culture systems. The first was an osteoclastic cell culture, and the second was a two-stage culture that was composed of a bonelike tissue formation on the substrata in the first stage and its subsequent resorption by osteoclasts in the second stage. Neither of the materials showed resorption or surface alterations in the osteoclastic cell culture, except for some limited phagocytotic activity on HA600 and HA900. In the two-stage culture, production of mineralized extracellular matrix was only observed on HA1250 and TCP, and its subsequent resorption by osteoclastlike cells was evident. Small and occasionally larger tartrate-resistant acid phosphatase positive cells produced 20-150 microns diameter resorption pits in both the mineralized extracellular matrix on HA1250 and TCP and the surfaces of HA600 and HA900. Resorption of the mineralized extracellular matrix on TCP also resulted in degradation of the underlying ceramic surface, mainly initiating from intergrain boundaries, whereas the surface of HA1250 remained unaltered. The results of this study clearly demonstrate that osteoclastic resorption of calcium phosphates is potentiated in postosteogenic culture conditions. A possible role for bone matrix constituents in cell-mediated resorption is hypothesized, whereas the occurrence of resorption seems to be mainly governed by the combined effects of material characteristics such as grain size and crystal structure.

The effect on immunocytes of anodic oxide titanium after hydrothermal treatment

“…16 However, plasma-sprayed HA-coated implant material has some problems, such as the low adhesive strength of the coating substrate interface and biodegration or bioresorption. 5 In order to cope with these problems, Ishizawa et al developed a method of forming a thin HA layer by means of anodization and hydrothermal treatment. Commercially pure titanium is anodized in an electrolytic solution of dissolved ␤-GP and CA to form an AOFCP on the surface.…”

“…[1][2][3] Furthermore, such implant materials have been researched and developed with regard to early osseointegration, and it has been demonstrated that plasma-sprayed hydroxyapatite (HA) coating on Ti implant materials enhances rapid bone formation because of their osteoconductive property compared with uncoated Ti implant materials. However, such problems as low adhesive strength of the coating substrate interface and significant biodegradation or bioresorption 5 have not been resolved. In order to cope with these problems, the Nikon Corporation improved the surface characteristics of Ti even further by developing a HA layer on the outer most surface, that is to say, the formation of an anodic Ti oxide film containing calcium and phosphate (AOFCP) by anodizing titanium in an aqueous electrolytic solution containing ␤-glycerophosphate and calcium acetate dissolved in water.…”

Use of glass slides coated with apatite-collagen complexes for measurement of osteoclastic resorption activity

“…The acidic microenvironment produced by osteoclasts and the surface of the mate- rials may be responsible for the degradation of these particles. 13,14 Furthermore, the activity of well-polarized multinucleated giant cells for ACC resorption may be enhanced. These findings are in agreement with those of previous studies in which sintered hydroxyapatite was shown to be resorbed by osteoclasts.…”

“…These findings are in agreement with those of previous studies in which sintered hydroxyapatite was shown to be resorbed by osteoclasts. 13,15 Osteologic was commercially developed for the measurement of osteoclast resorbing activity. 6 However, Osteologic is difficult to use for cytochemical analysis of activated osteoclasts because of the thick opaque crystal glass.…”

Superplastic Deformation in Carbonate Apatite Ceramics under Constant Compressive Loading for Near-net-shape Production of Bioresorbable Bone Substitutes

“…Carbonate apatite (CAP) is resorbed by osteoclasts 1,2) and is similar in biocompatibility to hydroxyapatite (HAP) 3) and β-tricalcium phosphate (β-TCP) 4) . Although the bioresorption mechanism of CAP may be different from that of β-TCP 5) , CAP dissolves to the same extent as β-TCP in weak acid media 1) .…”