The Experts below are selected from a list of 27 Experts worldwide ranked by ideXlab platform
Nicholas A. Athanasou - One of the best experts on this subject based on the ideXlab platform.
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The relationship of Wear volume with histological features in failed hip resurfacing arthroplasty: An insight on failures associated with pseudotumours
2013Co-Authors: Sion Glyn-jones, David W. Murray, Hemant Pandit, Amir Kamali, Richie Gill, Nicholas A. AthanasouAbstract:INTRODUCTION: Pseudotumours around Metal-on-Metal hip resurfacing arthroplasties (MoMHRA) have caused increased concern. Although pseudotumours are associated with increased prosthesis Wear, a few studies have suggested that they are not always associated with highly worn prostheses. This has led to the suggestion that the extensive necrosis and tissue destruction seen results not from the cytotoxic effect of the large number of Metal Particles on macrophages, which have phagocytosed these Particles, but from a hypersensitivity response to one or more Metal Wear Particle components. In keeping with this hypothesis, a prominent perivascular lymphoid infiltrate, commonly termed ALVAL, is frequently seen. Whether pseudotumours are due to Wear Particle-induced cytotoxicity, hypersensitivity or both remains to be determined. OBJECTIVES: The aim of this study was to correlate histopathological changes in periprosthetic tissues with clinical findings and the amount of implant-derived Metal Wear. METHODS: We analysed morphological changes in periprosthetic soft tissues of 56 failed MoMHRAs, all of which had bearing surface Wear measurements. The majority of revisions were in female hips and the mean age at primary MoMHRA was 56 years. The mean implant survival was 4.7 years. The majority of retrieved implants were BHR and Conserve Plus. The commonest cause of revision was the presence of a symptomatic pseudotumour (n=45). Other failures included fracture, impingement, unexplained pain, heterotopic ossification and cup loosening. The extent of tissue necrosis and the nature of the inflammatory cell infiltrate, including ALVAL, was evaluated semiquantitatively. Furthermore, tissues were graded using the ALVAL-score described by Campbell et al. Bearing surface Wear was determined for all patients using RedLux. Prostheses were considered to be highly worn if total linear Wear rate (TLWR) was 4μm/yr. All assessors were blinded to mode of failure and other measurements. RESULTS: Substantial necrosis and a heavy macrophage infiltrate were noted in most MoMHRA periprosthetic tissues, including all pseudotumours, many of which contained a significant ALVAL infiltrate. Most pseudotumours were associated with highly worn prostheses (80%). The extent of necrosis and macrophage infiltration correlated with the amount of prosthesis Wear. Wear weakly correlated with the amount of ALVAL measured quantitatively and with higher ALVAL scores as per Campbell. All pseudotumours with low Wear had a strong ALVAL response. CONCLUSION: The majority of pseudotumours are associated with increased Wear. This increased Wear is associated with necrosis and a heavy non-specific foreign body macrophage response coupled with a variable specific immune response (ALVAL). A minority of pseudotumours are associated with low Wear and a significant immune response. We hypothesise that the amount of Wear required to trigger an ALVAL response varies per individual; as the Wear volume increases, the chance of exceeding the individual’s threshold and triggering a response also increases. Surgeons should aim to minimise Wear as this would lead to a reduction in pseudotumour incidence. However, even under optimal conditions some pseudotumours can still occur due to an exacerbated immune response.
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The effect of Particle phagocytosis and Metallic Wear Particles on osteoclast formation and bone resorption in vitro
The Journal of arthroplasty, 2000Co-Authors: S D Neale, David R. Haynes, Donald W. Howie, David W. Murray, Nicholas A. AthanasouAbstract:Osteoclasts are multinucleated bone-resorbing cells that are formed from precursors that circulate in the monocyte fraction. This study has determined the effect of phagocytosis of Metal Particles on osteoclast formation and bone resorption in vitro. Human peripheral blood monocytes were cocultured for 21 days with osteoblast-like UMR 106 cells, in the presence of 1,25-dihydroxyvitamin D3, dexamethasone, and human macophage colony-stimulating factor. Cobalt-chrome alloy (CoCr), stainless steel (316L-SS), titanium alloy (TiAlV), and commercially pure titanium (cpTi) Particles (size range, 0.5-3.0 microm) and 1.0-microm latex Particles were added to the cocultures as a single dose at the beginning of each experiment. All 5 types of Particles were readily phagocytosed by the monocytes. After 4 days' exposure to high concentrations of all the Metal Particles, some cell death was found in the cocultures. After 14 days, a reduction in the number of CD14+ cells was seen in cocultures exposed to high concentrations of Metal Particles, particularly CoCr and 316L-SS Particles. Phagocytosis of latex Particles by osteoclast precursors did not affect the ability of these cells to undergo osteoclast differentiation. In contrast, exposure to Metal Wear Particle preparations caused a dose-dependent reduction in the number of vitronectin receptor-positive osteoclastic cells formed and a dose-dependent reduction in the bone resorption produced by these cells. This decrease in resorption was greater after exposure to CoCr and 316L-SS Particles compared with TiAlV and cpTi Particles. This in vitro cell culture system may provide a useful model to compare the effect of different prosthetic materials on human osteoclast formation and bone resorption.
Harlan C. Amstutz - One of the best experts on this subject based on the ideXlab platform.
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Metal Wear Particle characterization from Metal on Metal total hip replacements: Transmission electron microscopy study of periprosthetic tissues and isolated Particles
Journal of biomedical materials research, 1998Co-Authors: Peter F. Doorn, Pat Campbell, Jack Worrall, Paul D. Benya, Harry A. Mckellop, Harlan C. AmstutzAbstract:The less intense tissue reaction around Metal on Metal total hip replacements (THRs) compared to Metal on polyethylene (PE) THRs may be explained by the differences in the characteristics of Metal Wear Particles. In this study, transmission electron microscopy was used to study Metal Wear Particles that were either in situ in cells or had been extracted from the cells by a new technique based on enzymatic tissue digestion. The tissues were obtained from 13 patients undergoing revision of Metal on Metal THRs with cobalt-chromium-molybdenum (CoCrMo) bearing couples. Most of the CoCrMo Wear Particles were smaller than 50 nm (range 6-834 nm) and round to oval in shape with irregular boundaries. This size range is considerably smaller than that reported for PE Particles. While even a small volume of Metal Wear will produce high numbers of Particles, the apparently less severe local tissue reaction to Metal Particles may be due to the possibility that corrosion, dissolution, and dissemination of Metal Particles may result in fewer local biological effects than the long-term retention of PE Particles in the periprosthetic tissues.
David R. Haynes - One of the best experts on this subject based on the ideXlab platform.
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Osteocytes respond to Particles of clinically-relevant conventional and cross-linked polyethylene and Metal alloys by up-regulation of resorptive and inflammatory pathways
Acta biomaterialia, 2019Co-Authors: Renee T. Ormsby, David R. Haynes, Lucian B. Solomon, Dongqing Yang, Tania N. Crotti, David M. Findlay, Gerald J. AtkinsAbstract:Periprosthetic osteolysis is a major cause of implant failure in total hip replacements. Aseptic loosening caused by osteolytic lesions is associated with the production of bioactive Wear Particles from the articulations of implants. Wear Particles infiltrate the surrounding tissue of implants, promoting inflammation as well as bone resorption. Osteocytes have been shown to both regulate physiological osteoclastogenesis and directly remodel their perilacunar bone matrix by the process of osteocytic osteolysis. We hypothesise that osteocytes respond to Wear debris of orthopaedic implant materials by adopting a pro-catabolic phenotype and thus contribute to periprosthetic osteolysis through the known pathways of bone loss. Osteocyte responses to Particles derived from clinically relevant materials, ultra-high molecular weight polyethylene (UHMWPE), highly cross-linked polyethylene (XLPE) and Metal alloys, Ti6Al4V and CoCrMo, were examined in vitro in human primary osteocyte-like cultures. Osteocyte-like cells exposed to both polyethylene and Metal Wear Particle types showed upregulated expression of catabolic markers associated with osteocytic osteolysis, MMP13, carbonic anhydrase 2 (CA2) and cathepsin K (CTSK). In addition, pro-osteoclastogenesis markers RANKL and M-CSF were induced, as well as the expression of pro-inflammatory cytokines, IL-6 and TNFα, albeit with different kinetics. These findings suggest a previously unrecognised action of Wear Particles of multiple orthopaedic materials on osteocytes, and suggest a multifaceted role for osteocytes in periprosthetic osteolysis. STATEMENT OF SIGNIFICANCE: This study addresses periprosthetic osteolysis, a major clinical problem leading to aseptic loosening of orthopaedic implants. It is well accepted that Wear Particles of polyethylene and of other implant materials stimulate the activity of bone resorbing osteoclasts. Our recent work provided evidence that commercial Particles of ultra-high molecular weight polyethylene (UHMWPE) stimulated osteocytes to adopt a bone catabolic state. In this study we demonstrate for the first time that Particles derived from materials in clinical use, conventional UHMWPE, highly cross-linked polyethylene (XLPE), and Ti6Al4V and CoCrMo Metal alloys, all stimulate human osteocyte activities of osteocyte-regulated osteoclastogenesis, osteocytic osteolysis, proinflammatory responses, osteocyte apoptosis, albeit to varying extents. This study provides further mechanistic insight into orthopaedic Wear Particle mediated bone disease in terms of the osteocyte, the most abundant and key controlling cell type in bone.
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The effect of Particle phagocytosis and Metallic Wear Particles on osteoclast formation and bone resorption in vitro
The Journal of arthroplasty, 2000Co-Authors: S D Neale, David R. Haynes, Donald W. Howie, David W. Murray, Nicholas A. AthanasouAbstract:Osteoclasts are multinucleated bone-resorbing cells that are formed from precursors that circulate in the monocyte fraction. This study has determined the effect of phagocytosis of Metal Particles on osteoclast formation and bone resorption in vitro. Human peripheral blood monocytes were cocultured for 21 days with osteoblast-like UMR 106 cells, in the presence of 1,25-dihydroxyvitamin D3, dexamethasone, and human macophage colony-stimulating factor. Cobalt-chrome alloy (CoCr), stainless steel (316L-SS), titanium alloy (TiAlV), and commercially pure titanium (cpTi) Particles (size range, 0.5-3.0 microm) and 1.0-microm latex Particles were added to the cocultures as a single dose at the beginning of each experiment. All 5 types of Particles were readily phagocytosed by the monocytes. After 4 days' exposure to high concentrations of all the Metal Particles, some cell death was found in the cocultures. After 14 days, a reduction in the number of CD14+ cells was seen in cocultures exposed to high concentrations of Metal Particles, particularly CoCr and 316L-SS Particles. Phagocytosis of latex Particles by osteoclast precursors did not affect the ability of these cells to undergo osteoclast differentiation. In contrast, exposure to Metal Wear Particle preparations caused a dose-dependent reduction in the number of vitronectin receptor-positive osteoclastic cells formed and a dose-dependent reduction in the bone resorption produced by these cells. This decrease in resorption was greater after exposure to CoCr and 316L-SS Particles compared with TiAlV and cpTi Particles. This in vitro cell culture system may provide a useful model to compare the effect of different prosthetic materials on human osteoclast formation and bone resorption.
S D Neale - One of the best experts on this subject based on the ideXlab platform.
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The effect of Particle phagocytosis and Metallic Wear Particles on osteoclast formation and bone resorption in vitro
The Journal of arthroplasty, 2000Co-Authors: S D Neale, David R. Haynes, Donald W. Howie, David W. Murray, Nicholas A. AthanasouAbstract:Osteoclasts are multinucleated bone-resorbing cells that are formed from precursors that circulate in the monocyte fraction. This study has determined the effect of phagocytosis of Metal Particles on osteoclast formation and bone resorption in vitro. Human peripheral blood monocytes were cocultured for 21 days with osteoblast-like UMR 106 cells, in the presence of 1,25-dihydroxyvitamin D3, dexamethasone, and human macophage colony-stimulating factor. Cobalt-chrome alloy (CoCr), stainless steel (316L-SS), titanium alloy (TiAlV), and commercially pure titanium (cpTi) Particles (size range, 0.5-3.0 microm) and 1.0-microm latex Particles were added to the cocultures as a single dose at the beginning of each experiment. All 5 types of Particles were readily phagocytosed by the monocytes. After 4 days' exposure to high concentrations of all the Metal Particles, some cell death was found in the cocultures. After 14 days, a reduction in the number of CD14+ cells was seen in cocultures exposed to high concentrations of Metal Particles, particularly CoCr and 316L-SS Particles. Phagocytosis of latex Particles by osteoclast precursors did not affect the ability of these cells to undergo osteoclast differentiation. In contrast, exposure to Metal Wear Particle preparations caused a dose-dependent reduction in the number of vitronectin receptor-positive osteoclastic cells formed and a dose-dependent reduction in the bone resorption produced by these cells. This decrease in resorption was greater after exposure to CoCr and 316L-SS Particles compared with TiAlV and cpTi Particles. This in vitro cell culture system may provide a useful model to compare the effect of different prosthetic materials on human osteoclast formation and bone resorption.
Peter F. Doorn - One of the best experts on this subject based on the ideXlab platform.
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Metal Wear Particle characterization from Metal on Metal total hip replacements: Transmission electron microscopy study of periprosthetic tissues and isolated Particles
Journal of biomedical materials research, 1998Co-Authors: Peter F. Doorn, Pat Campbell, Jack Worrall, Paul D. Benya, Harry A. Mckellop, Harlan C. AmstutzAbstract:The less intense tissue reaction around Metal on Metal total hip replacements (THRs) compared to Metal on polyethylene (PE) THRs may be explained by the differences in the characteristics of Metal Wear Particles. In this study, transmission electron microscopy was used to study Metal Wear Particles that were either in situ in cells or had been extracted from the cells by a new technique based on enzymatic tissue digestion. The tissues were obtained from 13 patients undergoing revision of Metal on Metal THRs with cobalt-chromium-molybdenum (CoCrMo) bearing couples. Most of the CoCrMo Wear Particles were smaller than 50 nm (range 6-834 nm) and round to oval in shape with irregular boundaries. This size range is considerably smaller than that reported for PE Particles. While even a small volume of Metal Wear will produce high numbers of Particles, the apparently less severe local tissue reaction to Metal Particles may be due to the possibility that corrosion, dissolution, and dissemination of Metal Particles may result in fewer local biological effects than the long-term retention of PE Particles in the periprosthetic tissues.