Papers by Keyword: Osteoclast

Abstract: Bone graft materials are widely used in orthopedic and maxillofacial surgeries. The controlled resorbability of the graft material is essential for bone regeneration. Hydroxyapatite and biphasic calcium phosphate bone grafts have poor resorption and limited bone conductive effects. Histology analyses of bone biopsy from SCPC grafted human extraction sockets showed complete bone regeneration and graft resorption in absence of osteoclasts and macrophages. The hypothesis of the present study is that bioactive SCPC inhibits osteoclast’s activity due to the presence of resorbable silica phase in the material. Our objective is to analyze the effect of SCPC dissolution products on the resorption activity of osteoclasts. The conditioned medium was prepared by immersion of SCPC resorbable bioactive SCPC porous granules (Shefabone, Inc, USA) in cell culture medium at various ratios at 37°C for 3 days. The concentration of Si ions released from the SCPC granules into cell culture medium was measured using ICP-OES. Osteoclast precursors derived from human bone marrow were seeded on bone slices and cultured in the conditioned medium containing 10% FBS and osteoclast induction factors. Osteoclast differentiation and resorption were evaluated by TRAP staining and measurement of the volume of resorption pits on the bone slices. Mature multinuclear giant TRAP-positive osteoclasts were observed on the bone substrates after 14 days incubation in control medium containing osteoclast induction factors. In conditioned medium, the number of multinuclear TRAP-positive cells was significantly decreased as the concentration of SCPC dissolved silica increased. The dissolution of silica from SCPC into the culture medium correlates well with down regulation of osteoclast differentiation and the rapid bone regeneration in human bone defects.

Abstract: Punica granatum (PG) contained anthocyanin, the chemical compound that played significant role in increasing bone cell proliferabbitsion and osteoblasts differentiation in bone remodelling. This research was aimed at measuring the effect of Punica granatum on maxilla bone remodelling relating to the profile of both osteoblast and osteoclast. Punica granatum was extracted by using butanol while the analysis of bone remodelling was conducted by observing the profile of osteoblast and osteoclast cells using histopathologic method. Butanol hydrogel of Punica granatum was abled to enhance bone reabsorption which was proven by the increase of osteoclast and new bone formation since the osteoblast was presented. Moreover, bone remodelling activity was characterised by increased collagen fibres and osteocyte cell, in addition, bone shape compactness was getting better. Statistical analysis revealed that the histoscore profile of osteoblast was influenced by butanol fraction dosage with significance level (p<0.05) which was at medium criteria according to Pearson correlation (r=0,6). While the effect of dosage on osteoclast was at significance level (p<0.05) but was poorly correlated with (r=0.01) and osteoblast frequency was dominant at the concentrabbitsion of 125 mg/ml and 250 mg/ml. On the other hand, at the concentrabbitsion of 175 mg/ml osteoclast presentation was found to be more dominant. The fraction of butanol PG was abled to induce osteoblast increment and osteoclast at the concentrabbitsion of (mg/ml) 125, 175, and 250 and accelerabbitse the remodelling of alveolar maxilla.

Abstract: @font-face { font-family: "ＭＳ 明朝"; }@font-face { font-family: "Cambria Math"; }@font-face { font-family: "@ＭＳ 明朝"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0mm 0mm 0.0001pt; font-size: 10pt; font-family: "Times New Roman"; }.MsoChpDefault { font-size: 10pt; }div.WordSection1 { page: WordSection1; } Bioresorbable materials may be advantageous for use in bone regeneration applications because they do not leave residues of foreign material, improving the long-term success of implant restoration. The purpose of this study was to investigate the osteoclastogenesis and bioresorption of synthesized calcium phosphate ceramic materials for orthopaedic and dental biomaterial applications. Differentiation into mature human osteoclasts on carbonated hydroxyapatite (CA) was significantly enhanced compared to hydroxyapatite (HA). Osteoclasts derived from human peripheral mononuclear blood cells adhered and differentiated into giant multinuclear TRAP- positive cells on every type of synthesized sample based on the histological analysis. Morphological observations using fluorescence and quantitative analysis revealed that the actin rings of osteoclasts on CA were thick and small in diameter, similar to the rings found on bone slices. Scanning electron microscopic images and quantitative analysis indicated that the resorption pits on CA were significantly deeper than those on HA due to the enhanced tight sealing ability between osteoclasts and their substrate.

Abstract: It has been demonstrated that resveratrol can inhibit osteoclastogenesis induced by receptor activator of nuclear factor kappaB ligand (RANKL) in several cell models. However, the mechanism has not yet been completely clarified. In this study, we investigated the effects of resveratrol on osteoclasts differentiation induced by RANKL. Preosteoclast or osteoclast derived from the murine monocytic cell line RAW264.7 treated with RANKL. In RAW264.7 cells culture, data indicated that resveratrol at non-toxic concentrations dose-dependently inhibited the formation of osteoclasts and the activation of tartrate-resistant acid phosphatase (TRAP). Using flow cytometry assay, the results indicated that the percentage of preosteoclast differentiation was decreased by resveratrol, whereas the apoptosis rate of preosteoclasts was not changed. Our results suggest that resveratrol might inhibit the differentiation of RAW264.7 cells into osteoclasts and decrease osteoclast activation possibly via suppressing monocytes to differentiate preosteoclasts.

Abstract: Measurements of bone mineral density (BMD) cannot accurately predict the risk of bone fracture in some clinical cases; however, BMD is a useful index for assessing the bone condition. Recently, various parameters related to bone strength have been investigated. Among them, we have focused on the preferential orientation of biological apatite (BAp) crystallites analyzed by microbeam-X-ray diffraction, a powerful tool for analyzing BAp crystallites in bones. BAp, a dominant component of bone, is an anisotropic ionic crystal with a hexagonal lattice. In this study, we investigated the mechanism underlying BAp orientation during endochondral or membranous ossification by administering macrophage colony-stimulating factor (M-CSF) to osteopetrotic (op/op) mice lacking M-CSF. op/op mice were treated with intraperitoneal injections of 5 μg recombinant human M-CSF (rhM-CSF); the first injection was administered on the 14th day after birth. In the treated op/op mice, the bone marrow cavities expanded significantly, and this expansion was accompanied by an increase in the number of osteoclasts. Moreover, the degree of BAp orientation along the longitudinal axis was higher in the treated group than in the untreated group. These results suggest that M-CSF is one of the important parameters controlling the preferential alignment of the BAp c-axis.

Abstract: Our group focused on the preferential degree of biological apatite (BAp) c-axis, an important bone quality parameter based on the microstructural anisotropy in intact, pathological, and regenerated bones. The preferential degree of the BAp c-axis strongly depends on the bone position, in vivo stress distribution, bone growth, degree of pathology and regeneration, activity of bone cells, gene defect, etc. We attempted to challenge clarification of the BAp preferential alignment formation mechanism and control the degree of BAp orientation by using an anisotropic biomaterial design to develop suitable distribution of the BAp c-axis orientation.

Abstract: The diagnosis of hard tissues is generally carried out by bone mineral density (BMD) measurement as a bone quantity parameter. BMD, however, does not necessarily explain bone fracture risks in some clinical cases. Recently, various parameters relating to bone strength have been investigated. These additional parameters, so-called bone quality, reflect intrinsic bone conditions. We have been studying the preferential alignment of the biological apatite (BAp) c-axis among various bone quality parameters. BAp, a dominant component of hard tissue, is an ionic crystal that crystallizes in a hexagonal lattice accompanied with the anisotropic property. In this article, we investigated the osteoclast role in the recovery process of BAp orientation during bone regeneration using osteopetrotic (op/op) mice in which the number of osteoclasts decreases. A surgically drilled, 500-μm diameter hole on each tibia of both control and op/op 8-week-old mice was introduced from the medial surface into the medullary cavity located at a 30% length from the proximal tibia end. After surgery, tibiae injuries were regularly observed by in situ micro-CT, and then the mice were sacrificed four to eight weeks after surgery. BAp orientation was analyzed in and near the regenerated portion by the microbeam X-ray diffraction system. As a result, we found the insufficient recovery of BAp orientation in spite of the apparent repair of bone appearance and quantity from CT images, even eight weeks after surgery in both cases of control and op/op mice. We conclude that this defective animal model can be used to evaluate bone quantity and quality at the cortical portion during bone regeneration in gene-defect mice in which the expression of bone cells is controlled, for example.

Abstract: Osteoclast differentiation of bone marrow cells on hydroxyapatite/collagen self-organized bone-like nanocomposite (HAp/Col) disk in vitro was evaluated by coculture of mouse bone marrow cells with mouse osteoblasts with or without addition of osteoclastic inducers, 1,25-Dihydroxyvitamin D3 and 1 µM prostaglandin E2. Dentine slice and tissue culture polystyrene were used as controls. Good osteoclastic differentiation at day 7 were observed among the bone marrow cells cultured on the HAp /Col disk and controls with osteoclastic inducers. On the contrary, osteoclastic differentiation was observed only for marrow cells cultured on the HAp/Col disk. Nano- and micro- structures as well as chemical and mechanical properties have a potential to control cell differentiation.

Abstract: Beta-tricalcium phosphate(β-TCP) coating layer is known to be resorbed much faster than hydroxyapatite(HA), however, there has been no report to explain the exact reason of these results. Eighty titanium discs, coated with HA(n=40) or β-TCP(n=40) by dip and spin coating method, were divided into 2 subgroups respectively; Dissolution(D, n=20) and osteoclast culture(C, n=20). The coated discs in D group were immersed in the cell culture media for 5 days, whereas, in C group, osteoclasts were seeded on the specimens and cultured for 5 days. After simple dissolution test, β-TCP coating layer showed much more cracks and denudation as compared to HA. In osteoclast culture group, mean area fraction of resorption pits in HA-C group was 11.62%, which was significantly higher than that of 0.73% in β-TCP-C group(p=0.001). In conclusion, the resorption mechanisms of HA and β-TCP coating layers were different each other in vitro study. The coated β-TCP was degraded mainly by dissolution and separation from implant, on the other hand, the HA coating layer was resorbed by osteoclastic activity.

Abstract: In this paper, the iBone (Imitation Bone) model which is coupled with Turing reaction-diffusion system and FEM, is used. The numerical simulation of bone forming process by considering the osteoclasts and osteoblasts process are conducted. The results shown, that the bone mass is increased with increase of the initial load value, then fibula and femur bones are obtained respectively by keeping the required bone forming value. The different bone shapes are obtained by changing the both bone keeping value and the compressing force value. When set larger bone keeping value by keeping larger constant compressing force value, bone shape as a pipe with hole just like femur, when set smaller bone keeping value by keeping the smaller constant compressing force value, it is close to solid pillar as like fibula.