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Establishment of a novel in vitro test setup for electric and magnetic stimulation of human osteoblasts. Cell Biochem Biophys 2015; 70:805-17. [PMID: 24782061 DOI: 10.1007/s12013-014-9984-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
When large defects occur, bone regeneration can be supported by bone grafting and biophysical stimuli like electric and magnetic stimulation (EMS). Clinically established EMS modes are external coils and surgical implants like an electroinductive screw system, which combines a magnetic and electric field, e.g., for the treatment of avascular bone necrosis or pseudarthrosis. For optimization of this implant system, an in vitro test setup was designed to investigate effects of EMS on human osteoblasts on different 3D scaffolds (based on calcium phosphate and collagen). Prior to the cell experiments, numerical simulations of the setup, as well as experimental validation, via measurements of the electric parameters induced by EMS were conducted. Human osteoblasts (3 × 10(5) cells) were seeded onto the scaffolds and cultivated. After 24 h, screw implants (Stryker ASNIS III s-series) were centered in the scaffolds, and EMS was applied (3 × 45 min per day at 20 Hz) for 3 days. Cell viability and collagen type 1 (Col1) synthesis were determined subsequently. Numerical simulation and validation showed an adequate distribution of the electric field within the scaffolds. Experimental measurements of the electric potential revealed only minimal deviation from the simulation. Cell response to stimulation varied with scaffold material and mode of stimulation. EMS-stimulated cells exhibited a significant decrease of metabolic activity in particular on collagen scaffolds. In contrast, the Col1/metabolic activity ratio was significantly increased on collagen and non-sintered calcium phosphate scaffolds after 3 days. Exclusive magnetic stimulation showed similar but nonsignificant tendencies in metabolic activity and Col1 synthesis. The cell tests demonstrate that the new test setup is a valuable tool for in vitro testing and parameter optimization of the clinically used electroinductive screw system. It combines magnetic and electric stimulation, allowing in vitro investigations of its influence on human osteoblasts.
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Functionalized PLGA-doped zirconium oxide ceramics for bone tissue regeneration. Biomed Microdevices 2013; 15:1055-66. [DOI: 10.1007/s10544-013-9797-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Meester I, Solis-Soto JM. Cytokines: monitors of disease severity for the clinic. ACTA ACUST UNITED AC 2013; 3:143-55. [PMID: 23485161 DOI: 10.1517/17530050802708999] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND Cytokines communicate between the cells of the immune system and its targets to maintain homeostasis after injury or pathogenic events. They are involved in almost any pathological situation imaginable. OBJECTIVE To verify the importance of cytokines as biomarkers in current preclinical (aetiopathogenic, development of new therapies) and clinical studies (diagnosis, disease severity, prognosis and response to therapy). METHOD/RESULTS A Medline search with the query 'cytokine' AND 'biomarker' AND a variable for a variety of biomedical fields, followed by deeper-level searches, demonstrated the immense popularity of cytokines as biomarkers in almost any biomedical field. CONCLUSION As cytokines are not disease-specific they do not serve as single diagnostic biomarkers. The strength of the cytokines resides in monitoring disease severity, prognosis and response to treatment.
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Affiliation(s)
- Irene Meester
- Faculty of Medicine Department of Immunology, UANL, Gonzalitos 235, Mitras Centro, Monterrey, NL, Mexico, CP64460
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Heinemann S, Coradin T, Desimone MF. Bio-inspired silica–collagen materials: applications and perspectives in the medical field. Biomater Sci 2013; 1:688-702. [DOI: 10.1039/c3bm00014a] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Calcium phosphate phases integrated in silica/collagen nanocomposite xerogels enhance the bioactivity and ultimately manipulate the osteoblast/osteoclast ratio in a human co-culture model. Acta Biomater 2013; 9:4878-88. [PMID: 23072829 DOI: 10.1016/j.actbio.2012.10.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 09/05/2012] [Accepted: 10/05/2012] [Indexed: 02/05/2023]
Abstract
A human co-culture model of osteoblasts and osteoclasts, derived from bone marrow stromal cells and monocytes respectively, was used to characterize the influence of biomaterial modification on the bioactivity and ultimately the ratio of bone-forming to bone-resorbing cells cultivated directly on the surface. Nanocomposites of silica and collagen have been shown to function as skeletal structures in nature and were reproduced in vitro by using a sol-gel approach. The resulting xerogels exhibit a number of features that make it a valuable system for the development of innovative materials for bone substitution applications. In the present study, the incorporation of different calcium phosphate phases in silica/collagen-based gels was demonstrated to enhance the bioactivity of these samples. This ability of the biomaterial to precipitate calcium phosphate on the surface when incubated in simulated body fluids or cell culture medium is generally considered to an advantageous property for bone substitution materials. By co-cultivating human osteoblasts and osteoclasts up to 42 days on the xerogels, we demonstrate that the long-term ratio of these cell types depends on the level of bioactivity of the substrate samples. Biphasic silica/collagen xerogels exhibited comparably low bioactivity but encouraged proliferation of osteoblasts in comparison to osteoclast formation. A balanced ratio of both cell types was detected for moderately bioactive triphasic xerogels with 5% calcium phosphate. However, enhancing the bioactivity of the xerogel samples by increasing the calcium phosphate phase percentage to 20% resulted in a diminished number of osteoblasts in favor of osteoclast formation. Quantitative evaluation was carried out by biochemical methods (calcium, DNA, ALP, TRAP 5b) as well as RT-PCR (ALP, BSP II, OC, RANKL, TRAP, CALCR, VTNR, CTSK), and was supported by confocal laser scanning microscopy (cell nuclei, actin, CD68, TRAP) as well as scanning electron microscopy.
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Thimm BW, Hofmann S, Schneider P, Carretta R, Müller R. Imaging of Cellular Spread on a Three-Dimensional Scaffold by Means of a Novel Cell-Labeling Technique for High-Resolution Computed Tomography. Tissue Eng Part C Methods 2012; 18:167-75. [DOI: 10.1089/ten.tec.2011.0262] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Benjamin W. Thimm
- Department for Mechanical and Process Engineering, Institute for Biomechanics, ETH Zürich, Zürich, Switzerland
| | - Sandra Hofmann
- Department for Mechanical and Process Engineering, Institute for Biomechanics, ETH Zürich, Zürich, Switzerland
| | - Philipp Schneider
- Department for Mechanical and Process Engineering, Institute for Biomechanics, ETH Zürich, Zürich, Switzerland
| | - Roberto Carretta
- Department for Mechanical and Process Engineering, Institute for Biomechanics, ETH Zürich, Zürich, Switzerland
| | - Ralph Müller
- Department for Mechanical and Process Engineering, Institute for Biomechanics, ETH Zürich, Zürich, Switzerland
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Gredes T, Heinemann F, Dominiak M, Mack H, Gedrange T, Spassov A, Klinke T, Kunert-Keil C. Bone substitution materials on the basis of BONITmatrix® up-regulate mRNA expression of IGF1 and Col1a1. Ann Anat 2012; 194:179-84. [DOI: 10.1016/j.aanat.2011.10.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 09/13/2011] [Accepted: 10/07/2011] [Indexed: 11/17/2022]
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Unger RE, Halstenberg S, Sartoris A, Kirkpatrick CJ. Human endothelial and osteoblast co-cultures on 3D biomaterials. Methods Mol Biol 2011; 695:229-241. [PMID: 21042976 DOI: 10.1007/978-1-60761-984-0_15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Increasingly, in vitro experiments are being used to evaluate the cell compatibility of novel biomaterials. Single cell cultures have been used to determine how well cells attach, grow, and exhibit characteristic functions on these materials and the outcome of such tests is generally accepted as an indicator of biocompatibility. However, organs and tissues are not made up of one cell type and the interaction of cells is known to be an essential factor for physiological cell function. To more accurately examine biomaterials for bone regeneration, we have developed methods to coculture osteoblasts, which are the primary cell type making up bone, and endothelial cells, which form the vasculature supplying cells in the bone with oxygen and nutrients to survive on 2- and 3-D biomaterials.
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Affiliation(s)
- Ronald E Unger
- Institute of Pathology, Johannes Gutenberg University, Mainz, Germany
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In vitro models for the evaluation of angiogenic potential in bone engineering. Acta Pharmacol Sin 2011; 32:21-30. [PMID: 21042285 DOI: 10.1038/aps.2010.143] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Blood vessels have a fundamental role both in skeletal homeostasis and in bone repair. Angiogenesis is also important for a successful bone engineering. Therefore, scaffolds should be tested for their ability to favour endothelial cell adhesion, proliferation and functions. The type of endothelial cell to use for in vitro assays should be carefully considered, because the properties of these cells may depend on their source. Morphological and functional relationships between endothelial cells and osteoblasts are evaluated with co-cultures, but this model should still be standardized, particularly for distinguishing the two cell types. Platelet-rich plasma and recombinant growth factors may be useful for stimulating angiogenesis.
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Ketonis C, Barr S, Adams CS, Hickok NJ, Parvizi J. Bacterial colonization of bone allografts: establishment and effects of antibiotics. Clin Orthop Relat Res 2010; 468:2113-21. [PMID: 20361282 PMCID: PMC2895848 DOI: 10.1007/s11999-010-1322-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Bone grafts are frequently used to supplement bone stock and to establish structural stability. However, graft-associated infection represents a challenging complication leading to increased patient morbidity and healthcare costs. QUESTIONS/PURPOSES We therefore designed this study to (1) determine if increasing initial S. aureus inoculation of bone allograft results in a proportionate increase in colonization; (2) assess if antibiotics decrease colonization and if antibiotic tethering to allograft alters its ability to prevent bacterial colonization; and (3) determine if covalent modification alters the allograft topography or its biological properties. METHODS Allograft bone and vancomycin-modified bone (VAN-bone) was challenged with different doses of S. aureus for times out to 24 hours in the presence or absence of solution vancomycin. Bacterial colonization was assessed by fluorescence, scanning electron microscopy (SEM), and by direct colony counting. Cell density and distribution of osteoblast-like cells on control and modified allograft were then compared. RESULTS Bacterial attachment was apparent within 6 hours with colonization and biofilm formation increasing with time and dose. Solution vancomycin failed to prevent bacterial attachment whereas VAN-bone successfully resisted colonization. The allograft modification did not affect the attachment and distribution of osteoblast-like cells. CONCLUSIONS Allograft bone was readily colonized by S. aureus and covered by a biofilm with especially florid growth in natural topographic niches. Using a novel covalent modification, allograft bone was able to resist colonization by organisms while retaining the ability to allow adhesion of osteoblastic cells. CLINICAL RELEVANCE Generation of allograft bone that can resist infection in vivo would be important in addressing one of the most challenging problems associated with the use of allograft, namely infection.
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Affiliation(s)
- Constantinos Ketonis
- Department of Orthopedic Surgery, Thomas Jefferson University, Philadelphia, PA USA
| | - Stephanie Barr
- Department of Orthopedic Surgery, Thomas Jefferson University, Philadelphia, PA USA
| | - Christopher S. Adams
- Department of Orthopedic Surgery, Thomas Jefferson University, Philadelphia, PA USA
| | - Noreen J. Hickok
- Department of Orthopedic Surgery, Thomas Jefferson University, Philadelphia, PA USA ,Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA USA
| | - Javad Parvizi
- Department of Orthopaedic Surgery, Rothman Institute, Thomas Jefferson University, Philadelphia, PA 19107 USA
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Wu X, Wei J, Lu X, Lv Y, Chen F, Zhang Y, Liu C. Chemical characteristics and hemostatic performances of ordered mesoporous calcium-doped silica xerogels. Biomed Mater 2010; 5:35006. [DOI: 10.1088/1748-6041/5/3/035006] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Ghanaati SM, Thimm BW, Unger RE, Orth C, Kohler T, Barbeck M, Müller R, Kirkpatrick CJ. Collagen-embedded hydroxylapatite-beta-tricalcium phosphate-silicon dioxide bone substitute granules assist rapid vascularization and promote cell growth. Biomed Mater 2010; 5:25004. [PMID: 20208127 DOI: 10.1088/1748-6041/5/2/025004] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In the present study we assessed the biocompatibility in vitro and in vivo of a low-temperature sol-gel-manufactured SiO(2)-based bone graft substitute. Human primary osteoblasts and the osteoblastic cell line, MG63, cultured on the SiO(2) biomatrix in monoculture retained their osteoblastic morphology and cellular functionality in vitro. The effect of the biomaterial in vivo and its vascularization potential was tested subcutaneously in Wistar rats and demonstrated both rapid vascularization and good integration within the peri-implant tissue. Scaffold degradation was progressive during the first month after implantation, with tartrate-resistant acid phosphatase-positive macrophages being present and promoting scaffold degradation from an early stage. This manuscript describes successful osteoblastic growth promotion in vitro and a promising biomaterial integration and vasculogenesis in vivo for a possible therapeutic application of this biomatrix in future clinical studies.
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Reichert C, Al-Nawas B, Smeets R, Kasaj A, Götz W, Klein MO. In vitro proliferation of human osteogenic cells in presence of different commercial bone substitute materials combined with enamel matrix derivatives. Head Face Med 2009; 5:23. [PMID: 19909545 PMCID: PMC2780983 DOI: 10.1186/1746-160x-5-23] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2009] [Accepted: 11/12/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cellular reactions to alloplastic bone substitute materials (BSM) are a subject of interest in basic research. In regenerative dentistry, these bone grafting materials are routinely combined with enamel matrix derivatives (EMD) in order to additionally enhance tissue regeneration. MATERIALS AND METHODS The aim of this study was to evaluate the proliferative activity of human osteogenic cells after incubation over a period of seven days with commercial BSM of various origin and chemical composition. Special focus was placed on the potential additional benefit of EMD on cellular proliferation. RESULTS Except for PerioGlas, osteogenic cell proliferation was significantly promoted by the investigated BSM. The application of EMD alone also resulted in significantly increased cellular proliferation. However, a combination of BSM and EMD resulted in only a moderate additional enhancement of osteogenic cell proliferation. CONCLUSION The application of most BSM, as well as the exclusive application of EMD demonstrated a positive impact on the proliferation of human osteogenic cells in vitro. In order to increase the benefit from substrate combination (BSM + EMD), further studies on the interactions between BSM and EMD are needed.
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Affiliation(s)
- Christoph Reichert
- Department of Oral and Maxillofacial Surgery, University Hospital Aachen, Aachen, Germany.
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Computational modelling of the mechanical environment of osteogenesis within a polylactic acid-calcium phosphate glass scaffold. Biomaterials 2009; 30:4219-26. [PMID: 19477510 DOI: 10.1016/j.biomaterials.2009.04.026] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Accepted: 04/13/2009] [Indexed: 11/20/2022]
Abstract
A computational model based on finite element method (FEM) and computational fluid dynamics (CFD) is developed to analyse the mechanical stimuli in a composite scaffold made of polylactic acid (PLA) matrix with calcium phosphate glass (Glass) particles. Different bioreactor loading conditions were simulated within the scaffold. In vitro perfusion conditions were reproduced in the model. Dynamic compression was also reproduced in an uncoupled fluid-structure scheme: deformation level was studied analyzing the mechanical response of scaffold alone under static compression while strain rate was studied considering the fluid flow induced by compression through fixed scaffold. Results of the model show that during perfusion test an inlet velocity of 25 microm/s generates on scaffold surface a fluid flow shear stress which may stimulate osteogenesis. Dynamic compression of 5% applied on the PLA-Glass scaffold with a strain rate of 0.005 s(-1) has the benefit to generate mechanical stimuli based on both solid shear strain and fluid flow shear stress on large scaffold surface area. Values of perfusion inlet velocity or compression strain rate one order of magnitude lower may promote cell proliferation while values one order of magnitude higher may be detrimental for cells. FEM-CFD scaffold models may help to determine loading conditions promoting bone formation and to interpret experimental results from a mechanical point of view.
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