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Saban C, Roles J, Deprey J, Massenzio M, Viguier E, Cachon T. Ex vivo postimplantation biomechanical properties of a press-fit cementless femoral stem with transfixation pin for canine total hip replacement. Am J Vet Res 2022; 83:1-8. [PMID: 36136932 DOI: 10.2460/ajvr.22.05.0084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
OBJECTIVE To compare ex vivo postimplantation biomechanical characteristics of 3 implants for canine total hip replacement: a cementless press-fit femoral stem with a pin in the femoral neck (p-pfFS), a press-fit cementless femoral stem without this pin (pfFS), and a cemented femoral stem (cFS). SAMPLE 18 cadaveric femurs from 9 dogs. PROCEDURES Femurs were assigned randomly to 3 groups, and biomechanical testing was performed by measuring vertical displacement during cyclic loading and resistance to failure with compression parallel to the longitudinal axis of the femur. Force-displacement curves were assessed for failure tests, and work necessary for failure was calculated. RESULTS No significant differences were observed in vertical displacement during cyclic loading (P = .263) or work necessary for failure (P = .079). Loads to failure for cFS and p-pfFS implants were significantly greater than that for the pfFS, but no significant difference in load to failure was observed between cFS and p-pfFS implants (P = .48). CLINICAL RELEVANCE Cementless femoral stems with a transfixation pin offer significantly greater immediate resistance to failure to compressive loads parallel to the longitudinal axis of the femur than standard cementless stems, and a level of stability comparable to that of cemented stems. p-pfFS implants may be valuable in total hip replacement, potentially reducing the risk of fracture during the early postoperative period prior to osteointegration.
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Affiliation(s)
- Charles Saban
- Department of Small Animal Surgery, VetAgro-Sup, Campus Vétérinaire de Lyon, Marcy L'Etoile, France.,Unité ICE, VetAgro-Sup, Université de Lyon, Marcy L'Etoile, France
| | - Joséphine Roles
- Department of Small Animal Surgery, VetAgro-Sup, Campus Vétérinaire de Lyon, Marcy L'Etoile, France.,Unité ICE, VetAgro-Sup, Université de Lyon, Marcy L'Etoile, France
| | - Julie Deprey
- Department of Small Animal Surgery, VetAgro-Sup, Campus Vétérinaire de Lyon, Marcy L'Etoile, France.,Unité ICE, VetAgro-Sup, Université de Lyon, Marcy L'Etoile, France
| | - Michel Massenzio
- Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France
| | - Eric Viguier
- Department of Small Animal Surgery, VetAgro-Sup, Campus Vétérinaire de Lyon, Marcy L'Etoile, France.,Unité ICE, VetAgro-Sup, Université de Lyon, Marcy L'Etoile, France
| | - Thibaut Cachon
- Department of Small Animal Surgery, VetAgro-Sup, Campus Vétérinaire de Lyon, Marcy L'Etoile, France.,Unité ICE, VetAgro-Sup, Université de Lyon, Marcy L'Etoile, France
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Rony L, Pascaretti-Grizon F, Hubert L, Chappard D. Histochemical identification of wear debris released by alumina-on-alumina hip prostheses in the periprosthetic tissues. Orthop Traumatol Surg Res 2021; 107:102636. [PMID: 33023845 DOI: 10.1016/j.otsr.2020.03.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 03/09/2020] [Accepted: 03/18/2020] [Indexed: 02/03/2023]
Abstract
BACKGROUND Tribological studies have shown that the most used couples for hip prostheses consist of metal-on-polyethylene and alumina-on-alumina prostheses. Over time, wear products accumulate in the joint cavity and in the periprosthetic tissues. Although polyethylene and metal are easily identifiable by microscopy in periprosthetic tissues, alumina particles are very difficult to identify. HYPOTHESIS The fluorescent azo-dye lumogallion was evaluated as a suitable histochemical stain for alumina particles in periprosthetic tissues. MATERIAL AND METHOD In 28 patients who had a prosthetic revision of an alumina-on-alumina prosthesis, periprosthetic tissues were removed and embedded in paraffin; sections were stained with HPS (for conventional diagnosis) or with lumogallion. Sections were examined for wear particles in light and fluorescence microscopy. Some sections were counter-stained using DAPI for visualization of cell nuclei. RESULTS The wear particles of the alumina-alumina prostheses were very difficult to identify on the HPS stained sections; they were clearly evidenced by lumogallion staining with a bright orange fluorescence. The stain revealed large quantities of particles (of the order of several thousand per section). Only two patients had no particles. The staining technique identified numerous particles that were not visible on HPS-stained sections in macrophages, synoviocytes and fibroblasts. CONCLUSION This staining, which has been validated in neuromuscular pathology for the identification of alumina used as a vaccine adjuvant, gave successful results in the present study. Alumina particles are modified when they are phagocytized by macrophages. lumogallion staining easily shows the presence of thousands of wear particles released by alumina-on-alumina prostheses in periprosthetic tissues. LEVEL OF EVIDENCE V expert opinion study.
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Affiliation(s)
- Louis Rony
- Groupe Etudes Remodelage Osseux et bioMatériaux, GEROM, EA-4658, SFR-4208, Univ-Angers, IRIS-IBS Institut de Biologie en Santé, CHU-Angers, 49933 Angers, France; Département de chirurgie osseuse, CHU-Angers, 49033 Angers, France
| | - Florence Pascaretti-Grizon
- Groupe Etudes Remodelage Osseux et bioMatériaux, GEROM, EA-4658, SFR-4208, Univ-Angers, IRIS-IBS Institut de Biologie en Santé, CHU-Angers, 49933 Angers, France
| | - Laurent Hubert
- Groupe Etudes Remodelage Osseux et bioMatériaux, GEROM, EA-4658, SFR-4208, Univ-Angers, IRIS-IBS Institut de Biologie en Santé, CHU-Angers, 49933 Angers, France; Département de chirurgie osseuse, CHU-Angers, 49033 Angers, France
| | - Daniel Chappard
- Département de chirurgie osseuse, CHU-Angers, 49033 Angers, France.
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Mahon OR, O'Hanlon S, Cunningham CC, McCarthy GM, Hobbs C, Nicolosi V, Kelly DJ, Dunne A. Orthopaedic implant materials drive M1 macrophage polarization in a spleen tyrosine kinase- and mitogen-activated protein kinase-dependent manner. Acta Biomater 2018; 65:426-435. [PMID: 29104084 DOI: 10.1016/j.actbio.2017.10.041] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 10/25/2017] [Accepted: 10/27/2017] [Indexed: 12/17/2022]
Abstract
Total joint replacements (TJR) are costly procedures required to relieve pain and restore function in patients suffering from end-stage arthritis. Despite great progress in the development and durability of TJRs, the generation of prosthesis-associated wear particles over time leads to an inflammatory cascade which culminates in periprosthetic osteolysis. Studies suggest that wear particles drive the polarization/differentiation of immature macrophages towards a pro-inflammatory M1 phenotype rather than an anti-inflammatory M2 phenotype associated with normal bone and wound healing. This, in turn, contributes to the initiation of peri-implant inflammation. As a result, modulating M1 macrophage cytokine production has been recognised as a viable therapeutic option. The aim of this study was to examine the impact of hydroxyapatite (HA) and poly(methyl methacrylate) (PMMA) particles on human macrophage polarization by comparing their effect on M1/M2-associated gene expression using real-time PCR. Furthermore, using immunoblotting to assess kinase activation, we sought to identify the intracellular signalling molecules activated by PMMA/HA particles and to determine whether pharmacological blockade of these molecules impacts on macrophage phenotype and cytokine production as measured by ELISA. We report that wear particles preferentially polarize macrophages towards an M1 phenotype, an effect that is dependent on activation of the membrane proximal kinase, Syk and members of the mitogen-activated protein kinase (MAPK) family of signalling molecules. Pre-treatment of macrophages with Syk inhibitors (R788/piceatannol) or MAPK inhibitors (SB203580 and PD98059), not only prevents M1 polarization, but also attenuates production of key pro-inflammatory mediators that have been specifically implicated in periprosthetic osteolysis and osteoclast differentiation. STATEMENT OF SIGNIFICANCE It is now well established that wear-debris particles from implanted materials drive deleterious inflammatory responses which can eventually lead to implant loosening. In this study, we provide further insight into the specific cellular pathways activated by wear particles in primary human immune cells. We demonstrate that PMMA bone cement and hydroxyapatite, a commonly used biomaterial, drive the polarization of macrophages towards an inflammatory phenotype and identify the specific signalling molecules that are activated in this process. Pre-treatment of macrophages with pharmacological inhibitors of these molecules in turn prevents macrophage polarization and dampens inflammatory cytokine production. Hence these signalling molecules represent potential therapeutic targets to treat or possibly prevent particulate induced osteolysis.
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Characterization of wear debris released from alumina-on-alumina hip prostheses: Analysis of retrieved femoral heads and peri-prosthetic tissues. Micron 2018; 104:89-94. [DOI: 10.1016/j.micron.2017.11.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 11/03/2017] [Accepted: 11/03/2017] [Indexed: 11/20/2022]
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Moran MM, Wilson BM, Ross RD, Virdi AS, Sumner DR. Arthrotomy-based preclinical models of particle-induced osteolysis: A systematic review. J Orthop Res 2017; 35:2595-2605. [PMID: 28548682 PMCID: PMC5702596 DOI: 10.1002/jor.23619] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 05/24/2017] [Indexed: 02/04/2023]
Abstract
We completed a systematic literature review of in vivo animal models that use arthrotomy-based methods to study particle-induced peri-implant osteolysis. The purpose of the review was to characterize the models developed to date, to determine the questions addressed, to assess scientific rigor and transparency, and to identify gaps in knowledge. We probed three literature databases (Medline, Embase, and Scopus) and found 77 manuscripts that fit the search parameters. In the most recent 10 years, researchers mainly used rat and mouse models, whereas in the previous 20 years, large animal, canine, and rabbit models were more common. The studies have demonstrated several pathophysiology pathways, including macrophage migration, particle phagocytosis, increased local production of cytokines and lysosomal enzymes, elevated bone resorption, and suppressed bone formation. The effect of variation in particle characteristics and concentration received limited attention with somewhat mixed findings. Particle contamination by endotoxin was shown to exacerbate peri-implant osteolysis. The possibility of early diagnosis was demonstrated through imaging and biomarker approaches. Several studies showed that both local and systemic delivery of bisphosphonates inhibits the development of particle-induced osteolysis. Other methods of inhibiting osteolysis include the use of anabolic agents and altering the implant design. Few studies examined non-surgical rescue of loosened implants, with conflicting results with alendronate. We found that the manuscripts often lacked the methodological detail now advocated by the ARRIVE guidelines, suggesting that improvement in reporting would be useful to maximize rigor and transparency. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2595-2605, 2017.
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Affiliation(s)
- Meghan M. Moran
- Department of Anatomy and Cell Biology, Rush University Medical Center
| | | | - Ryan D. Ross
- Department of Anatomy and Cell Biology, Rush University Medical Center
| | - Amarjit S. Virdi
- Department of Anatomy and Cell Biology, Rush University Medical Center
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Cyndari KI, Goodheart JR, Miller MA, Oest ME, Damron TA, Mann KA. Peri-Implant Distribution of Polyethylene Debris in Postmortem-Retrieved Knee Arthroplasties: Can Polyethylene Debris Explain Loss of Cement-Bone Interlock in Successful Total Knee Arthroplasties? J Arthroplasty 2017; 32:2289-2300. [PMID: 28285038 PMCID: PMC5469692 DOI: 10.1016/j.arth.2017.01.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 01/06/2017] [Accepted: 01/25/2017] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Loss of mechanical interlock between cement and bone with in vivo service has been recently quantified for functioning, nonrevised, cemented total knee arthroplasties (TKAs). The cause of interlocking trabecular resorption is not known. The goal of this study is to quantify the distribution of PE debris at the cement-bone interface and determine if polyethylene (PE) debris is locally associated with loss of interlock. METHODS Fresh, nonrevised, postmortem-retrieved TKAs (n = 8) were obtained en bloc. Laboratory-prepared constructs (n = 2) served as negative controls. The intact cement-bone interface of each proximal tibia was embedded in Spurr's resin, sectioned, and imaged under polarized light to identify birefringent PE particles. PE wear particle number density was quantified at the cement-bone interface and distal to the interface, and then compared with local loss of cement-bone interlock. RESULTS The average PE particle number density for postmortem-retrieved TKAs ranged from 8.6 (1.3) to 24.9 (3.1) particles/mm2 (standard error) but was weakly correlated with years in service. The average particle number density was twice as high as distal (>5mm) to the interface compared to at the interface. The local loss of interlock at the interface was not related to the presence, absence, or particle density of PE. CONCLUSION PE debris can migrate extensively along the cement-bone interface of well-fixed tibial components. However, the amount of local bone loss at the cement-bone interface was not correlated with the amount of PE debris at the interface, suggesting that the observed loss of trabecular interlock in these well-fixed TKAs may be due to alternative factors.
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Affiliation(s)
- Karen I Cyndari
- Department of Orthopaedic Surgery, State University of New York Upstate Medical University, Syracuse, New York
| | - Jacklyn R Goodheart
- Department of Orthopaedic Surgery, State University of New York Upstate Medical University, Syracuse, New York
| | - Mark A Miller
- Department of Orthopaedic Surgery, State University of New York Upstate Medical University, Syracuse, New York
| | - Megan E Oest
- Department of Orthopaedic Surgery, State University of New York Upstate Medical University, Syracuse, New York
| | - Timothy A Damron
- Department of Orthopaedic Surgery, State University of New York Upstate Medical University, Syracuse, New York
| | - Kenneth A Mann
- Department of Orthopaedic Surgery, State University of New York Upstate Medical University, Syracuse, New York
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Massin P, Achour S. Wear products of total hip arthroplasty: The case of polyethylene. Morphologie 2016; 101:1-8. [PMID: 27426252 DOI: 10.1016/j.morpho.2016.06.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 05/26/2016] [Accepted: 06/15/2016] [Indexed: 11/20/2022]
Abstract
Among the bearing surfaces involved in a total hip arthroplasty, ultra-high molecular weight polyethylene (UHMWPE) is the weak link. It is submitted to the friction of a harder bearing, producing wear particles, which, in turn, initiate an inflammatory reaction ultimately leading to osteolysis. This kind of bone deterioration sometimes turns out to an aggressive granuloma and may provoke implant loosening. Wear resistance of UHMWPE depends on its molecular weight and crystallinity. Some steps of the manufacturing process were improved to optimize its tribological properties and to slow down degradation resulting from mechanical (abrasion) and chemical (oxidation) phenomena. Its preparation and conservation must be performed in an inert atmosphere, i.e. without ambient oxygen. Its resistance to abrasion depends on its cross-linking degree. Its cross-linking rate was observed to increase proportionally to the irradiation doses, improving its wear resistance. However, its mechanical properties are impaired and moreover, it becomes oxidation sensitive. It is therefore necessary to submit it to a thermal treatment to eliminate free radicals that were produced during irradiation. More recently impregnation by vitamin E, a powerful anti-oxidant product, was proposed to preserve the polymer from in vivo oxidation while maintaining its mechanical properties. We raised the hypothesis that last-generation UHMWPE could offer the same wear resistance as the most performing bearings (ceramic-on-ceramic). Recent clinical results confirm the tribological performance of highly crosslinked UHMWPE in vivo. However, it remains to be seen whether this excellent wear resistance would persist under eccentric load such as edge loading, and if, in the long run, this kind of bearing proves capable of reducing the risk of osteolysis in young and active patients.
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Affiliation(s)
- P Massin
- Département de chirurgie orthopédique, hôpitaux universitaires Paris Nord Val-de-Seine, site Beaujon, 100, boulevard du General-Leclerc, 92110 Clichy, France.
| | - S Achour
- Département de chirurgie orthopédique, hôpitaux universitaires Paris Nord Val-de-Seine, site Beaujon, 100, boulevard du General-Leclerc, 92110 Clichy, France
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The dog as a preclinical model to evaluate interface morphology and micro-motion in cemented total knee replacement. Vet Comp Orthop Traumatol 2011; 25:1-10. [PMID: 22028048 DOI: 10.3415/vcot-11-01-0014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Accepted: 08/23/2011] [Indexed: 11/17/2022]
Abstract
OBJECTIVES This study investigated cemented fixation of the tibial component from a canine total knee replacement preclinical model. The objective was to determine the local morphology at the material interfaces (implant, cement, bone) and the local relative micro- motion due to functional loading following in vivo service. METHODS Five skeletally mature research dogs underwent unilateral total knee replacement using a cemented implant system with a polyethylene (PE) monobloc tibial component. Use of the implanted limb was assessed by pressure-sensitive walkway analysis. At 60 weeks post-surgery, the animals were euthanatized and the tibia sectioned en bloc in the sagittal plane to create medial and lateral specimens. High resolution imaging was used to quantify the morphology under the tray and along the keel. Specimens were loaded to 50% body weight and micro- motions at the PE-cement and cement-bone interfaces were quantified. RESULTS There was significantly (p = 0.002) more cement-bone apposition and interdigitation along the central keel compared to the regions under the tray. Cavitary defects were associated with the perimeters of the implant (60 ± 25%). Interdigitation fraction was negatively correlated with cavitary defect fraction, cement crack fraction, and total micro-motion. CLINICAL SIGNIFICANCE Achieving good interdigitation of cement into subchondral bone beneath the tibial tray is associated with improved interface morphology and reduced micro-motion; features that could result in a reduced incidence of aseptic loosening. Multiple drill holes distributed over the cut tibial surface and adequate pressurization of the cement into the subchondral bone should improve fixation and reduce interface micromotion and cavitary defects.
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Migration of wear debris of polyethylene depends on bone microarchitecture. J Biomed Mater Res B Appl Biomater 2009; 90:730-7. [DOI: 10.1002/jbm.b.31341] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Iesaka K, Jaffe WL, Kummer FJ. Integrity of the stem-cement interface in THA: Effects of stem surface finish and cement porosity. J Biomed Mater Res B Appl Biomater 2008; 87:77-82. [DOI: 10.1002/jbm.b.31071] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Mann KA, Miller MA, Cleary RJ, Janssen D, Verdonschot N. Experimental micromechanics of the cement-bone interface. J Orthop Res 2008; 26:872-9. [PMID: 18253965 PMCID: PMC2405909 DOI: 10.1002/jor.20575] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Despite the widespread use of cement as a means of fixation of implants to bone, surprisingly little is known about the micromechanical behavior in terms of the local interfacial motion. In this work, we utilized digital image correlation techniques to quantify the micromechanics of the cement-bone interface of laboratory-prepared cemented total hip replacements subjected to nondestructive, quasistatic tensile and compressive loading. Upon loading, the majority of the displacement response localized at the contact interface region between cement and bone. The contact interface was more compliant (p = 0.0001) in tension (0.0067 +/- 0.0039 mm/MPa) than compression (0.0051 +/- 0.0031 mm/MPa), and substantial hysteresis occurred due to sliding contact between cement and bone. The tensile strength of the cement-bone interface was inversely proportional to the compliance of the interface and proportional to the cement/bone contact area. When loaded beyond the ultimate strength, the strain localization process continued at the contact interface between cement and bone with microcracking (damage) to both. More overall damage occurred to the cement than to the bone. The opening and closing at the contact interface from loading could serve as a conduit for submicron size particles. In addition, the cement mantle is not mechanically supported by surrounding bone as optimally as is commonly assumed. Both effects may influence the longevity of the reconstruction and could be considered in preclinical tests.
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Affiliation(s)
- Kenneth A. Mann
- Department of Orthopaedic Surgery, 3216 Institute for Human Performance, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, New York 13210
| | - Mark A. Miller
- Department of Orthopaedic Surgery, 3216 Institute for Human Performance, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, New York 13210
| | - Richard J. Cleary
- Department of Mathematical Sciences, Bentley College, Waltham, Massachusetts
| | - Dennis Janssen
- Department of Orthopaedic Surgery, 3216 Institute for Human Performance, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, New York 13210
| | - Nico Verdonschot
- Orthopaedic Research Laboratory, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Moreau MF, Guillet C, Massin P, Chevalier S, Gascan H, Baslé MF, Chappard D. Comparative effects of five bisphosphonates on apoptosis of macrophage cells in vitro. Biochem Pharmacol 2006; 73:718-23. [PMID: 17157266 DOI: 10.1016/j.bcp.2006.09.031] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Revised: 09/21/2006] [Accepted: 09/21/2006] [Indexed: 01/19/2023]
Abstract
Bisphosphonates (BPs) inhibits bone resorption by reducing osteoclastic activity; they induce osteoclast apoptosis. Pathophysiology of prostheses loosening is complex and implies an inflammatory reaction secondary to the phagocytosis of wear debris by macrophages with a secondary increased bone resorption by osteoclasts. BPs inhibit proliferation and cause cell death in macrophages by induction of apoptosis. We have used mouse macrophage-like J774.1 cells to evaluate the effects of five BPs. J774A.1 cells were cultured in a standard culture medium for 2-days. BPs (alendronate, pamidronate, etidronate, risedronate, zoledronic acid) were added in the medium at concentration of 10(-6) to 10(-4)M during 3 days. Cells were studied by fluorescence microscopy after staining with the fluorescent dye Hoescht H33342 and the percentage of apoptotic cells was determined on 300 nuclei. Cells were analyzed by flow cytofluorometry after staining with annexin V-FITC (for counting apoptotic cells) and propidium iodide (for necrotic/late-apoptotic cells) on 2000 cells. Etidronate did not cause significant apoptosis or necrosis, at any concentration. Alendronate and pamidronate caused apoptosis and death only at very high concentration [10(-4)M]. On the contrary, apoptotic and necrotic cells were evidenced with risedronate or zoledronic acid at lower concentrations. These effects were dose-dependant and occurred when concentration reached [10(-5)M]. The number of apoptotic cells was higher with zoledronic acid and then with risedronate. Cytofluorometry appeared superior to cytologic analysis in the investigation of macrophage apoptosis, since necrotic cells loose contact with the glass slides and are not identifiable in cytological counts. Some amino-BPs appear to induce apoptosis in macrophages.
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Affiliation(s)
- M F Moreau
- INSERM, EMI 0335, LHEA, Faculté de Médecine, 49045 Angers Cédex, France
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