Papers by Keyword: Bone Repair

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Authors: Veronique Viateau, G. Guillemin, Y. Calando, K. Oudina, Laurent Sedel, Didier Hannouche, H. Petite
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Authors: Kalle Aitasalo, Matti Peltola, J. Suonpää, Antti Yli-Urpo
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Authors: Roberta Martinetti, L. Dolcini, Luisia Merello, Silvia Scaglione, Rodolfo Quarto, Daniele Pressato
Abstract: The use of 3D osteoconductive scaffolds provides an informative substrate serving as a physical support matrix for in vivo tissue regeneration. In the last few years the use of bioengineered 3D scaffolds has been becoming the most promising experimental approach for the regeneration of living tissues. Stem cells are typically used, in combination with 3D substrates, to promote in vivo bone regeneration and repair. For tissue engineering applications, biomaterials should therefore be able to support the functional properties of osteo-progenitor cells, giving them the optimal microenvironment to perform their physiological activity. Inorganic biomaterials are particularly relevant for bone regeneration; calcium phosphate ceramics have in fact been shown to strongly interact with bone tissue. The aim of the present work was to evaluate two different scaffolds with a defined design and different composition developed to guide/promote tissue repair.
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Authors: N. Ignjatović, P. Ninkov, Z. Ajduković, V. Konstantinović, Dragan P. Uskokovic
Abstract: Composite biomaterials, like calciumphosphate/bioresorbable polymer, offer excellent potential for reconstruction and reparation of bone tissue defects induced by different sources. In this paper synthesis of calciumphosphate/poly-DL-lactide-co-glycolide (BCP/DLPLG) composite biomaterial formed as filler and blocks was studied. BCP/DLPLG composite biomaterial was produced in the form of spherical granules of BCP covered by a DLPLG layer, average diameter of 150-250 µm. By cold and hot pressing of granules at up to 10000 kg/cm2, blocks with fine distribution of phases and porosity up to 3% were obtained. Characterization was performed by wide-angle X-ray structural analysis (WAXS), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), infrared spectroscopy (IR), and mechanical properties by defining the compressive strength. In vitro citotoxicity research was carried out on cellular cultures of fibroblasts of human (MRC5) and mouse (L929). In vivo research was performed in two steps. Reparatory ability of BCP/DLPLG in mice was examined in the first step, and then bone tissue reconstruction possibilities on 10 patients in the next step. In vitro tests showed very good fibroblast adhesion and non-citotoxicity of the composite. A material is considered non-cytotoxic if the cell survival is above 50 %, and in our case it was 90%. In vivo research on mice indicated high level of reparatory ability of this composite with formation of new bone and vascular tissue six weeks after reparation. Application of this composite for healing infrabone defects of patients showed a high level of osseous regeneration.
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Authors: Oliver Malard, Jean Michel Bouler, Jerome Guicheux, Olivier Gauthier, E. Lerouxel, G. Daculsi
Abstract: Bone invasion is common in case of Squamous Cell Carcinomas (SCC) of the upper aero-digestive tract. Radiotherapy is required in addition to large surgical tumor removal. This treatment usually generates irreversible injuries on the reparation properties of the tissues, especially on bone. The quality of life of patients undergoing major surgery and radiotherapy in maxillary and mandible areas is reduced, but could be improved by bone reconstruction. The aim of this study was to evaluate the bone reconstruction possibilities by Macroporous Biphasic Calcium-Phosphate (MBCPÔ). The MBCP substitute was evaluated as granules and associated to autologous bone marrow (BM) graft in irradiated areas, in an inbreeding rodent model. Radiation sequels were created on inferior members of half of the rats. 3 weeks later, 3-mm osseous defects were created on each animal. The inbreeding model allows BM to be grafted without graft-versus-host reaction. Defects were filled either with MBCP alone, BM alone or a mixture of MBCP and BM. Six weeks after implantation, animals were sacrificed: bone repair and ceramic degradation were evaluated by qualitative and quantitative study. Results showed that bioceramics were well osteointegrated. Filling the defects with BM alone showed a significant increased of newly-formed bone formation but only after irradiation, whereas filling defects with MBCP alone increased new-bone formation only without previous irradiation. Associating MBCP to BM provided the best new-bone formation rates after irradiation. Degradation of the ceramic was the most important in case of BM grafting. This study demonstrated that BM added to MBCP constitute an appropriate material to be considered in case of bone defect occurring in irradiated tissue, and could be foreseen for use after bone removal for oncologic obligations.
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Authors: Bruno Giorno, Igor Iuco Castro-Silva, Alexandre Malta Rossi, José Mauro Granjeiro
Abstract: Hydroxyapatite is the main ceramic material that has being used in bone repair, although its physico-chemical and in vivo behavior should be better understood. A method to improve the biocompatibility of HA is the substitution of calcium with divalent cations which enhance mechanic resistance and can modulate inflammatory response against implanted material. In this study we analyzed the biocompatibility of HA doped with one per cent of Zn2+ or Pb2+. The first one has being described as an inflammation modulator and the second would be a model for chronic toxicity assay. Biocompatibility of the both materials was studied in vivo following the ISO 10993-6 standard. HA cylinders (ZnHA, PbHA and stoichiometric HA as positive control) were implanted into subcutaneous tissue of 45 Balb-c mice and after 1, 3 and 9 weeks the animals were euthanized (5 for each experimental condition). Necropsies of the skin containing reactional tissue were removed, fixed in 10% formaldehyde and followed the histological processing for paraffin embedding and staining with Hematoxylin-Eosine and Picrosirius red. Microscopic analysis showed for all groups moderate inflammatory response, decreasing throughout the experimental periods, with ZnHA group showing more intense response. Similar presence of macrophages, fibrosis and angiogenesis were observed among the groups. Thereby, we can conclude that ZnHA and PbHA are biocompatible and not bioresorbable, being the ZnHA potentially indicated as bone graft. Detailed studies are required to better understand the role of PbHA as chronic model for lead toxicity.
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Authors: Silvia Farè, Luigi de Nardo, S. De Cicco, M. Jovenitti, Maria Cristina Tanzi
Abstract: In the last few years, clinical procedures undergone huge modifications. Among them, mini-invasive surgery has modified the clinical practice and the quality of life of patients. Shape Memory Polymers (SMPs), a class of stimuli-responsive materials, can be considered ideal candidates for the design of devices for mini-invasive surgical procedures. Such a device can be inserted in a packed in, temporary shape and later can expand at body temperature. A bone defect could be filled by a SMP porous structure, that improves the tissue integration and healing. In this work, two different processing techniques to obtain porous shape memory polymer scaffolds from Calo MER™ and MM-4520, two SMPs, are presented. Porous structures were obtained by micro-extrusion with different chemical foaming agents or with sodium chloride, or by solvent casting/particulate leaching. The morphology, the thermo-mechanical and the shape recovery properties of the SMP porous samples were investigated. Tridimensional porous structures showed a well interconnected morphology, with a pore size in the range aimed for bone interaction applications. The shape memory properties were not significantly affected by the transformation processes: a good ability of recovering the original shape was verified. Therefore, the porous structures, obtained from these SMP materials, appear adequate for an use as bone filler.
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Authors: Monica Calasans-Maia, G.V.O. Fernandes, Antonella M. Rossi, Eliane Pedra Dias, G.D.S. Almeida, F.F. Mitri, José Mauro Granjeiro
Abstract: Hydroxyapatite (HA), widely used as bone graft, can be modified by the incorporation of bivalent cations (Mg2+ and Zn2+) and its gradual release could favor the bone repair. The purpose of this research was to evaluate the effect of the HA and zinc-containing hydroxyapatite (Zn-HA) in the bone repair in rat calvaria in comparison to autogenous bone. Critical size defect in the calvaria was filled with the graft material and the samples were harvested at the 30, 90 and 180 days. The light microcopy observations showed the biocompatibility of the graft materials. In the Zn-HA group the area of neoformed bone was larger than in the HA group, but smaller than in the autograft. A fibrous connective tissue was more evident around HA granules. It could be conclude that the presence of zinc ions in HA crystal accelerated the osteogenesis and increased the area of newly formed bone in relation to HA.
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Authors: Zhen Ran Xia, Miao Liang Luo, Qin Zhang, Jing Qu, Ming Zhong Li
Abstract: In order to investigate the effects of addition amount, particle size distribution and aver- age particle size of NaCl porogen on the pore connectivity of silk fibroin (SF) / hydroxyapatite (HA) porous composites. In this paper, the SF/HA composites were fabricated by means of isostatic pressing. The pore structure of SF/HA porous composites was observed by Scanning electron microscopy (SEM), and the air permeability was tested by home-made device. Results indicated that the larger addition amount of NaCl particles, the greater scope of NaCl particles size distribution and increased the average particle size of NaCl particles were able to make the pore connectivity of the material improved significantly. The materials with good pore connectivity, which were conducive to the immigration and adhesion of bone repair cells, information transmission and exchange with the outside tissue, and also benefit for bone tissue regeneration.
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Authors: J.H. Lim, J.H. Park, Eui Kyun Park, Hae Jung Kim, Il Kyu Park, H.Y. Shin, Hong In Shin
Abstract: An appropriate scaffold, which provides structural support for transplanted cells and acts as a vehicle for the delivery of biologically active molecules, is critical for tissue engineering. We developed a fully interconnected globular porous biphasic calcium phosphate ceramic scaffold by adopting a foaming method, and evaluated its efficiency as a bone substitute and a scaffold for bone tissue engineering by in vitro and in vivo biocompatible analysis and its osteogenic healing capacity in rat tibial bone defects. They have spherical pores averaging 400um in diameter and interconnecting interpores averaging 70um in diameter with average 85% porosity. They elicited no cytotoxicity and noxious effect on cellular proliferation and osteoblastic differentiation during the cell-scaffold construct formation. Also the bone defects grafted with fully interconnected globular porous biphasic calcium phosphate ceramic blocks revealed excellent bone healing within 3 weeks. These findings suggest that the fully interconnected porous biphasic calcium phosphate scaffold formed by the foaming method can be a promising bone substitute and a scaffold for bone tissue engineering.
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