Papers by Keyword: Osteocalcin

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Authors: Larry L. Hench, Julia M. Polak
Abstract: Historically the function of biomaterials has been to replace diseased, damaged and aged tissues. First generation biomaterials, including bio ceramics, were selected to be as inert as possible in order to minimize the thickness of interfacial scar tissue. Bioactive glasses provided an alternative from the 1970’s onward; second generation bioactive bonding of implants with tissues and no interfacial scar tissue. This chapter reviews the discovery that controlled release of biologically active Ca and Si ions from bioactive glasses leads to the up-regulation and activation of seven families of genes in osteoprogenitor cells that give rise to rapid bone regeneration. This finding offers the possibility of creating a new generation of gene activating bioceramics designed specially for tissue engineering and in situ regeneration of tissues.
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Authors: J.L. Xu, Khiam Aik Khor, W.N. Chen
Abstract: Hydroxyapatite based biomaterials were prepared by a spark plasma sintering technology. The human limb-derived osteoblasts were cultured on the various biomaterial surfaces (HA, RF21, 1SiHA and 5SiHA) for up to two weeks to investigate the cellular behaviors. The bone gammacarboxyglutamic protein or osteocalcin in the medium were determined at different periods of cell culture. The results indicated that a combined effect of bioceramic surface composition and surface morphology had influenced the osteoblast behaviors. The amount of osteocalcin in the medium increased in the initial periods of culture but decreased in the late periods of culture.
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Authors: Y. Liu, J.E. Barralet, P. Cooper, R.M. Shelton
Abstract: According to the gene repertoire, distinct morphology and the organisation of extracellular matrix, osteoblast development was identified as a series of stages, proliferation, differentiation, matrix deposition, matrix maturation and mineralization. Each of these stages required tightly regulated and functionally coupled expression of genes related to the transcription factors and bone matrix. In this paper, we identify the effects of OCP to the differentiation of osteoblasts from the point of view of differentiation sequence development. Osteogenic medium (Ost MEM) mainly regulated the osteocalcin (OC) mRNA expression in the first week of culture. As culture continued to 24 days, OCP crystal assemblies became the main regulator. This shift in the role that OCP and Ost MEM played in regulation may reflect different biological functions of OC in Ost MEM induced regulation and OCP crystals induced regulation. The up-regulated OC mRNA expression by OCP crystal assemblies may function as a signal to coordinate the activities of osteoblasts and osteoclasts instead of inducing mineralisation at the end of the differentiation sequence of osteoblasts. By comparing the modified expression pattern observed on the OCP crystal particles with the patterns of differentiation sequences, it was found that BMSCs colonising OCP crystal assemblies from day 7 to day 24 matched the process of differentiation in the early stages of matrix deposition. The gene expressions of BMSC cultured in the osteogenic medium (positive control) corresponded with the process from matrix deposition to mineralisation. Hence, the differentiation process of BMSCs on OCP crystal assemblies was different from that found on the positive control. BMSCs could differentiate to osteoblasts that would function as a regulator for osteoclast activities.
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Authors: Yan Fei Tan, Ling Li Zhang, Xin Lai He, Wei Qiang Xiao, Hong Song Fan, Xing Dong Zhang
Abstract: The osteoinduction of Calcium Phosphate (CaP) had been proved and generally been investigated by in vivo implantation. However, the mechanism of the osteoinductivity was not clear and it was difficult to judge the osteoinductivity in vitro. In this study, Mouse C2C12 cell line, a kind of myoblast precursor cell, was employed to co-culture with CaP. The induction of cell differentiation by materials was tested by MTT method, fluorescence observation, especially the mRNA expression of Osteocalcin, Type I collagen and Fibronectin by RT-PCR. It was founded that C2C12 cells could be induced to expression osteocalcin when growth on the surface of the HA/TCP ceramics. At the same time, the ceramics with different composition and sintering temperature seemed to induce difference expression level of the related genes. The results proved that phase composition was one of the most important factors in the regulation of bone-related genes. This study provided a potential model to evaluate the osteoinductivity of CaP ceramics in vitro.
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Authors: Sandris Petronis, Janis Locs, Vita Zalite, Mara Pilmane, Andrejs Skagers, Ilze Salma, Girts Salms
Abstract: Calcium bone substitutes are successfully used for local recovery of osteoporotic bone and filling of bone defects. Previous studies revieled that biphasic calcium phosphate (BCP) show better bioactivity in compare to pure β-tricalcium phosphate or hydroxyapatite. Also increased porosity of material promotes better bone tissue response. Aim of this experiment was to evaluate immunohistologically response of osteoporotic bone of experimental animal to implantation of granules with hydroxyapatite/β-tricalcium phosphate (HAp/β-TCP) ratio of 90/10. Calcium phosphate (CaP) was synthesized by aqueous precipitation technique from calcium hydroxide and phosphoric acid. Bioceramic granules in size range from 1.0 to 1.4 mm were prepared with nanopore sizes around 200 nm. We used nine female rabbits with induced osteoporosis in this experiment. Six animals in study group underwent implantation of BCP in hip bone defect and three animals in control group left without BCP implantation. After 6 months animals were euthanized, bone samples collected and proceeded for detection of bone activity and repair markers: osteocalcin (OC), osteopontin (OP) and osteoprotegerin (OPG). Controls showed the presence of experimental bone osteoporosis. In experimental group bone showed partially resorbed bioceramic granules and in some samples new bone formation near the granuli was observed. Increase of OC and OPG up to twice as to compare to control group were detected as well. Implantation of BCP granules in osteoporotic rabbit bone increases expression of OC and OPG indicating the activation of osteoblastogenesis and bone mineralization in vivo.
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Authors: Miho Nakamura, Y. Sekijima, Takayuki Kobayashi, Satoshi Nakamura, Kimihiro Yamashita
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Authors: Yan Fei Tan, Gang Wang, Hong Song Fan, Xin Long Wang, Jian Lu, Xing Dong Zhang
Abstract: The mRNA expression of Cbfa1 and osteocalcin gene induced by calcium phosphate ceramics (Ca/P) were quantitative analyzed according to real-time RT-PCR method in this work. C2C12 cells were co-culture with four kinds of porous Ca/P ceramics for 2 and 5d without adding other growth factors. The four kinds of Ca/P ceramics were pure hydroxyapatite (HA) sintered at 1250°C and HA/TCP with a ratio of 60/40 sintered at 1100°C (HT1), 1200°C (HT2) and 1250°C (HT3) respectively. Real-time RT-PCR analysis found the Ca/P ceramics induced positive expression of Cbfa1 and osteocalcin in C2C12 cells, After 5 days culture, Cbfa1 and osteocalcin showed obvious higher expression compared with that in 2 days. Cbfa1 and osteocalcin expression in BCP was much higher than HA, and the expression level of osteocalcin was HT1>HT2>HT3>HA. Our results showed that Ca/P ceramics alone were sufficient to induce C2C12 cells to osteoblastic differentiation and the sinter temperature and phase composition of Ca/P ceramics could affect their osteoindctive capacity significantly.
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Authors: Meera Q. Arumugam, D.C. Ireland, Roger A. Brooks, Neil Rushton, William Bonfield
Abstract: The object of this study was to investigate the effect of the concentration of orthosilicic acid (0, 0.5, 1, 5 and 10µM) on gene expression in human osteoblast cells isolated from trabecular bone. This was measured using reverse transcriptase-polymerase chain reaction (RT-PCR) to quantify messenger RNA (mRNA) levels for collagen type I, alkaline phosphatase and osteocalcin. Results showed that while collagen type I mRNA expression was increased by the addition of up to 10µM orthosilicic acid, ALP message was suppressed over time and osteocalcin levels were decreased.
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Authors: Elisa Battistella, Silvia Mele, S. Pietronave, Ismaela Foltran, G.I. Lesci, Elisabetta Foresti, Norberto Roveri, Lia Rimondini
Abstract: Nature is full of many interesting things to work with, but many natural resources are also protected. In this view the recycling of aquaculture and fishery residues may lead to the manufacture of new devices and the isolation of new molecules with potential application in medicine. The aim of the present study was to explore the possibility to transform the cuttlefish bone into an hydroxyapatite scaffold suitable for bone tissue engineering application. The mixture of different lamellar porous structure of cuttlefish bone from the species Sepia Officinalis was selected and characterized, according to morphology (including porosity, surface development, surface characteristics) and mechanical properties. The material was transformed into suitable scaffold for bone tissue regeneration, trying to totally or partially convert calcium carbonate (aragonite) into calcium phosphate (hydroxyapatite HA) using hydrothermal transformation. The studies on cell attachment and proliferation (by MTT assay at different experimental times), cell morphology with Scanning Electron Microscopy (SEM), alkaline phosphatase (ALP) and osteocalcin (OC) activities and expressions by mouse osteoblast-like MC3T3-E1 cells on HA were investigated at different experimental times in cultures, in comparison with those observed on titanium specimens used as a control (ET and ST). Cell proliferation was less in HA transformed cuttlefish bone scaffolds than in ET and ST specimens. In contrast, good performance for osteoblasts differentiation was observed on HA transformed cuttlefish bone scaffolds, similar to those observed onto titanium scaffolds.
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