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Enayati M, Puchhammer S, Iturri J, Grasl C, Kaun C, Baudis S, Walter I, Schima H, Liska R, Wojta J, Toca-Herrera JL, Podesser BK, Bergmeister H. Assessment of a long-term in vitro model to characterize the mechanical behavior and macrophage-mediated degradation of a novel, degradable, electrospun poly-urethane vascular graft. J Mech Behav Biomed Mater 2020; 112:104077. [PMID: 32942230 DOI: 10.1016/j.jmbbm.2020.104077] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 08/13/2020] [Accepted: 08/23/2020] [Indexed: 10/23/2022]
Abstract
An assessment tool to evaluate the degradation of biodegradable materials in a more physiological environment is still needed. Macrophages are critical players in host response, remodeling and degradation. In this study, a cell culture model using monocyte-derived primary macrophages was established to study the degradation, macro-/micro-mechanical behavior and inflammatory behavior of a new designed, biodegradable thermoplastic polyurethane (TPU) scaffold, over an extended period of time in vitro. For in vivo study, the scaffolds were implanted subcutaneously in a rat model for up to 36 weeks. TPU scaffolds were fabricated via the electrospinning method. This technique provided a fibrous scaffold with an average fiber diameter of 1.39 ± 0.76 μm and an average pore size of 7.5 ± 1.1 μm. The results showed that TPU scaffolds supported the attachment and migration of macrophages throughout the three-dimensional matrix. Scaffold degradation could be detected in localized areas, emphasizing the role of adherent macrophages in scaffold degradation. Weight loss, molecular weight and biomechanical strength reduction were evident in the presence of the primary macrophage cells. TPU favored the switch from initial pro-inflammatory response of macrophages to an anti-inflammatory response over time both in vitro and in vivo. Expression of MMP-2 and MMP-9 (the key enzymes in tissue remodeling based on ECM modifications) was also evident in vitro and in vivo. This study showed that the primary monocyte-derived cell culture model represents a promising tool to characterize the degradation, mechanical behavior as well as biocompatibility of the scaffolds during an extended period of observation.
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Affiliation(s)
- Marjan Enayati
- Center for Biomedical Research, Medical University of Vienna, Vienna, Austria; Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria
| | - Sarah Puchhammer
- Center for Biomedical Research, Medical University of Vienna, Vienna, Austria
| | - Jagoba Iturri
- Institute for Biophysics, Department of Nanobiotechnology, BOKU University for Natural Resources and Life Sciences, Vienna, Austria
| | - Christian Grasl
- Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria; Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria
| | - Christoph Kaun
- Division of Internal Medicine II, Medical University Vienna, Austria
| | - Stefan Baudis
- Institute of Applied Synthetic Chemistry, Technische Universität Wien, Vienna, Austria
| | - Ingrid Walter
- Department of Pathobiology, Veterinary University, Vienna, Austria
| | - Heinrich Schima
- Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria; Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria
| | - Robert Liska
- Institute of Applied Synthetic Chemistry, Technische Universität Wien, Vienna, Austria
| | - Johann Wojta
- Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria; Division of Internal Medicine II, Medical University Vienna, Austria
| | - José Luis Toca-Herrera
- Institute for Biophysics, Department of Nanobiotechnology, BOKU University for Natural Resources and Life Sciences, Vienna, Austria
| | - Bruno K Podesser
- Center for Biomedical Research, Medical University of Vienna, Vienna, Austria; Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria
| | - Helga Bergmeister
- Center for Biomedical Research, Medical University of Vienna, Vienna, Austria; Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria.
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Frazão LP, Vieira de Castro J, Neves NM. In Vivo Evaluation of the Biocompatibility of Biomaterial Device. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1250:109-124. [PMID: 32601941 DOI: 10.1007/978-981-15-3262-7_8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Biomaterials are widely used to produce devices for regenerative medicine. After its implantation, an interaction between the host immune system and the implanted biomaterial occurs, leading to biomaterial-specific cellular and tissue responses. These responses may include inflammatory, wound healing responses, immunological and foreign-body reactions, and even fibrous encapsulation of the implanted biomaterial device. In fact, the cellular and molecular events that regulate the success of the implant and tissue regeneration are played at the interface between the foreign body and the host inflammation, determined by innate and adaptive immune responses. This chapter focuses on host responses that must be taken into consideration in determining the biocompatibility of biomaterial devices when implanted in vivo of animal models.
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Affiliation(s)
- L P Frazão
- I3B's - Research Institute on Biomaterials, Biodegradables and Biomimetics of University of Minho: 3Bs Research Group, Guimarães, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - J Vieira de Castro
- I3B's - Research Institute on Biomaterials, Biodegradables and Biomimetics of University of Minho: 3Bs Research Group, Guimarães, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Nuno M Neves
- I3B's - Research Institute on Biomaterials, Biodegradables and Biomimetics of University of Minho: 3Bs Research Group, Guimarães, Portugal.
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
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3
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Santos TC, Reis RL, Marques AP. Can host reaction animal models be used to predict and modulate skin regeneration? J Tissue Eng Regen Med 2016. [DOI: 10.1002/term.2128] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- T. C. Santos
- 3Bs Research Group - Biomaterials, Biodegradables and Biomimetics; University of Minho, Taipas, and ICVS-3Bs - PT Government Associate Laboratory; Braga/Guimarães Portugal
| | - R. L. Reis
- 3Bs Research Group - Biomaterials, Biodegradables and Biomimetics; University of Minho, Taipas, and ICVS-3Bs - PT Government Associate Laboratory; Braga/Guimarães Portugal
| | - A. P. Marques
- 3Bs Research Group - Biomaterials, Biodegradables and Biomimetics; University of Minho, Taipas, and ICVS-3Bs - PT Government Associate Laboratory; Braga/Guimarães Portugal
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Cao Y, He W. Water-soluble antioxidant derivative poly(triethylene glycol methyl acrylate-co-α-tocopheryl acrylate) as a potential prodrug to enable localized neuroprotection. Acta Biomater 2013; 9:4558-68. [PMID: 22939925 DOI: 10.1016/j.actbio.2012.08.037] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 07/30/2012] [Accepted: 08/26/2012] [Indexed: 11/28/2022]
Abstract
Implantable microelectrode arrays (MEA) hold enormous hope for individuals with sensory or motor deficits. However, long-term function of MEA remains a critical hurdle. The objective of this study was to synthesize an antioxidant prodrug that can be delivered to the neural tissue around the implant and present a pharmacological depot to combat the injurious oxidative stress around the MEA. In this report, monomers of triethylene glycol methyl acrylate and α-tocopheryl acrylate, a synthetic derivative of the antioxidant α-tocopherol (vitamin E, Ve), were copolymerized to obtain poly(triethylene glycol methyl acrylate-co-α-tocopheryl acrylate) (PVT) with different compositions. In contrast to the poor water solubility of Ve, solubility of the PVT prodrug in water can reach as high as 3.1 mg ml(-1) (equivalent to 500 μM Ve) by tuning the copolymer composition. To demonstrate the applicability of the prodrug for MEA implants, PVT was successfully deposited on silicon substrates with poly(acrylic acid) (PAA) or tannic acid (TA) using the layer-by-layer technique mediated by hydrogen bonding. Ellipsometry and quartz crystal microbalance data showed that the multilayers of PAA/PVT were destructible at physiological pH. In contrast, multilayers of TA/PVT were stable. The PVT prodrug was non-cytotoxic toward A172 human astrocytes. Furthermore, PVT was able to protect astrocytes against oxidative stress exerted by H(2)O(2) in vitro. Using a free radical scavenging assay, the protection mechanism was attributed to the hydrolysis of the labile ester linkage and release of the active Ve.
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Affiliation(s)
- Y Cao
- Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996, USA
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Barbosa JN, Barbosa MA, Aguas AP. Inflammatory responses and cell adhesion to self-assembled monolayers of alkanethiolates on gold. Biomaterials 2004; 25:2557-63. [PMID: 14751741 DOI: 10.1016/j.biomaterials.2003.09.047] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The acute inflammatory response and the adhesion of cells to self-assembled monolayers (SAMs) of well-defined surface chemistry was studied in vivo using a rodent air-pouch model of inflammation. SAMs with three different terminal functional groups (OH, COOH and CH3) were implanted in subcutaneous air pouches induced in BALB/c mice. After 24 h, inflammatory cells were recovered from the air pouches and the implants were removed and prepared for observation by scanning electron microscopy (SEM). The implants coated with OH and CH3, were found to cause the highest recruitment of inflammatory cells into the subcutaneous pouches. Polymorphonuclear neutrophils (PMNs) leukocytes predominated over mononuclear cells in inflammatory exudates of SAMs-coated implants, the opposite being found in uncoated implants (controls). CH3-coated implants induced the highest number of inflammatory cells and also the largest percentage of PMNs seen in the subcutaneous pouches. Control and OH-covered implants presented the higher densities of attached inflammatory cells detected by SEM. In contrast, the CH3-coated implants showed a very low density of cells adherent to the implant surface. We conclude that the chemical nature and the degree of hydrophobicity of the surface of implants modulate both the local acute inflammatory reaction and the adhesion of leukocytes.
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Affiliation(s)
- Judite N Barbosa
- Laboratório de Biomaterials (INEB), Instituto de Engenharia Biomédica, Rua do Campo Alegre 823, 4150-180 Porto, Portugal.
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Iribarren P, Correa SG, Sodero N, Riera CM. Activation of macrophages by silicones: phenotype and production of oxidant metabolites. BMC Immunol 2002; 3:6. [PMID: 12095418 PMCID: PMC117237 DOI: 10.1186/1471-2172-3-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2002] [Accepted: 07/01/2002] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The effect of silicones on the immune function is not fully characterized. In clinical and experimental studies, immune alterations associated with silicone gel seem to be related to macrophage activation. In this work we examined in vivo, phenotypic and functional changes on peritoneal macrophages early (24 h or 48 h) and late (45 days) after the intraperitoneal (i.p.) injection of dimethylpolysiloxane (DMPS) (silicone). We studied the expression of adhesion and co-stimulatory molecules and both the spontaneous and the stimulated production of reactive oxygen intermediates and nitric oxide (NO). RESULTS The results presented here demonstrate that the fluid compound DMPS induced a persistent cell recruitment at the site of the injection. Besides, cell activation was still evident 45 days after the silicone injection: activated macrophages exhibited an increased expression of adhesion (CD54 and CD44) and co-stimulatory molecules (CD86) and an enhanced production of oxidant metabolites and NO. CONCLUSIONS Silicones induced a persistent recruitment of leukocytes at the site of the injection and macrophage activation was still evident 45 days after the injection.
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Affiliation(s)
- Pablo Iribarren
- Inmunología. Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000. Córdoba. Argentina
| | - Silvia G Correa
- Inmunología. Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000. Córdoba. Argentina
| | - Natalia Sodero
- Inmunología. Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000. Córdoba. Argentina
| | - Clelia M Riera
- Inmunología. Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000. Córdoba. Argentina
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Hooper KA, Nickolas TL, Yurkow EJ, Kohn J, Laskin DL. Characterization of the inflammatory response to biomaterials using a rodent air pouch model. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2000; 50:365-74. [PMID: 10737878 DOI: 10.1002/(sici)1097-4636(20000605)50:3<365::aid-jbm10>3.0.co;2-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Using a rodent air pouch, the inflammatory responses to biomaterials with distinct physical properties and chemical compositions were compared. The polymers examined were expanded poly(tetrafluoroethylene) (ePTFE), silicone, low-density polyethylene (LDPE), poly(L-lactic acid) (PLLA), poly(desaminotyrosyl-tyrosine ethyl carbonate) [poly(DTE carbonate)], and poly(desaminotyrosyl-tyrosine benzyl carbonate) [poly(DTBzl carbonate)]. We found that implantation of disks (4.5-4.8 mm) of these materials into rodent air pouches for 2 days had no effect on the number or type of cells recovered relative to sham controls. With each of the materials, macrophages were the predominant cell type identified (60-75%), followed by granulocytes (20-25%) and lymphocytes (10%). Implantation of poly(DTE carbonate), ePTFE, LDPE, or poly(DTBzl carbonate) into the pouches for 2 days caused an increase in release of superoxide anion by the pouch cells. Cells from pouches containing poly(DTE carbonate) also released more hydrogen peroxide and were more phagocytic. In contrast, PLLA and silicone had no effect on the functional activity of cells recovered from the pouches. Prolonging the implantation time of poly(DTE carbonate) or PLLA to 7 days did not alter the number or type of cells isolated from the pouches. However, cells from pouches containing poly(DTE carbonate) for 7 days continued to produce increased quantities of superoxide anion relative to sham control pouch cells. These results suggest that the air pouch model is a highly sensitive method and therefore useful for evaluating the functional responses of inflammatory cells to biomaterials.
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Affiliation(s)
- K A Hooper
- Department of Pharmacology and Toxicology, Rutgers-The State University of New Jersey, Piscataway, New Jersey 08854-8020, USA
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Ciapetti G, Granchi D, Verri E, Savarino L, Cenni E, Savioli F, Pizzoferrato A. Fluorescent microplate assay for respiratory burst of PMNs challenged in vitro with orthopedic metals. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1998; 41:455-60. [PMID: 9659615 DOI: 10.1002/(sici)1097-4636(19980905)41:3<455::aid-jbm15>3.0.co;2-h] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This report describes a simple, rapid, automated microassay for measuring in vitro changes of oxidative burst of phagocytes following challenge with metals for orthopedic devices. The production of reactive oxygen species (ROS) by polymorphonuclear leukocytes (PMNs) was measured using 2',7'-dichlorofluorescin-diacetate (DCFH-DA) as fluorescent probe. DCFH-DA enters the cells and is oxidized by ROS to fluorescent DCF. The DCF generated was directly proportional to ROS produced intracellularly: The fluorescence intensity was read and converted to an index of ROS production by cells. In our experimental system, granulocytes (PMNs) were isolated from normal human blood and seeded in microplates. To verify if metals could influence ROS production, chromium, cobalt, nickel, molybdenum, titanium, aluminum, and vanadium prepared as aqueous extracts in phosphate-buffered saline were tested onto PMNs using phorbolmyristate acetate (PMA) as positive control. Molybdenum, aluminum, and vanadium increased ROS generation by PMNs, while signals not different from unstimulated PMNs were recorded for chromium, cobalt, nickel, and titanium. The DCFH-DA microplate-based assay provides an in vitro tool for the detection of oxygen-reactive species generated by PMNs as a response to metals.
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Affiliation(s)
- G Ciapetti
- Laboratory for Biocompatibility Research on Implant Materials, Istituti Ortopedici Rizzoli, Bologna, Italy
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Milam SB. Failed implants and multiple operations. ORAL SURGERY, ORAL MEDICINE, ORAL PATHOLOGY, ORAL RADIOLOGY, AND ENDODONTICS 1997; 83:156-62. [PMID: 9007940 DOI: 10.1016/s1079-2104(97)90107-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- S B Milam
- Department of Oral and Maxillofacial Surgery, University of Texas Health Science Center, San Antonio, USA
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Huber TS, Welling TH, Sarkar R, Messina LM, Stanley JC. Effects of retroviral-mediated tissue plasminogen activator gene transfer and expression on adherence and proliferation of canine endothelial cells seeded onto expanded polytetrafluoroethylene. J Vasc Surg 1995; 22:795-803. [PMID: 8523615 DOI: 10.1016/s0741-5214(95)70071-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
PURPOSE Seeding prosthetic arterial grafts with genetically modified endothelial cells (ECs) has the potential to substantially improve graft function. However, preliminary applications suggest that grafts seeded with retrovirally transduced ECs yield a significantly lower percent surface coverage than those seeded with nontransduced ECs. The objective of this study was to test the hypothesis that canine ECs transduced with the human tissue plasminogen activator (tPA) gene would have a lower rate of adherence to pretreated expanded polytetrafluoroethylene (ePTFE) both in vitro and in vivo and that they would proliferate at a slower rate on pretreated ePTFE in vitro. METHODS Early passage ECs derived from canine external jugular vein were transduced with the retroviral MFG vector containing the gene for human tPA. ECs exposed to media alone served as controls. Iodine 125-labeled ECs were seeded in vitro onto ePTFE graft segments pretreated with canine whole blood, fibronectin (50 micrograms/ml), or media alone, and the percent of ECs adherent at 1 hour were determined (n = 3). Additional tPA-transduced and -nontransduced ECs were grown for 10 days on either fibronectin (50 micrograms/ml)-pretreated ePTFE wafers or tissue culture plastic pretreated with gelatin (1%) or fibronectin (50 micrograms/ml), and the EC proliferation rates were determined (n = 3). Furthermore, 125I-labeled ECs were seeded onto fibronectin (50 micrograms/ml)-pretreated ePTFE graft segments implanted as carotid and femoral artery interposition grafts (n = 3). The grafts were harvested after 1 hour, and the percent of ECs adherent was determined. RESULTS Human tPA was detected by immunohistochemical staining in 61% +/- 5% of the transduced ECs and was expressed at 35.4 +/- 12.9 ng/hr/10(6) cells. Fibronectin and whole blood pretreatment of the ePTFE grafts led to greater EC adherence in vitro than did media alone (90.9% +/- 5.3% vs 77.8% +/- 5.8% vs 4.7% +/- 1.1%, p < or = 0.05). No significant difference in the rates of adherence or proliferation was seen in vitro between the transduced and nontransduced ECs. No significant difference in proliferation was found for the transduced ECs on the three matrices tested in vitro. In contrast, adherence of the transduced ECs in vivo was significantly lower than that of nontransduced ECs (64.7% +/- 2.1% vs 73.7% +/- 4.1%, p < or = 0.05) 1 hour after implantation. CONCLUSIONS Lower rates of surface endothelialization by genetically modified ECs in vivo do not appear to be due to an impaired capacity to initially adhere or proliferate on the synthetic graft but may result from decreased adherence after exposure to in vivo hemodynamic forces.
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Affiliation(s)
- T S Huber
- Jobst Research Laboratories, Department of Surgery, University of Michigan Medical School, Ann Arbor, USA
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Milam SB. A protocol for the management of failed alloplastic temporomandibular joint disc implants. J Oral Maxillofac Surg 1995. [DOI: 10.1016/0278-2391(95)90578-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Abstract
The biostability of polyurethanes was evaluated using a human neutrophil cell culture. The polymers were synthesized with 14C radiolabelled components incorporated into the polyurethane chain and the amount of radiolabel released during exposure to cells and medium was used as a marker for material degradation. The effect of diisocyanate, soft segment and chain extender chemistry on the susceptibility of polymer degradation was examined. All polymers showed a release of material into the tissue culture medium which was unrelated to the cells. A significant cell-dependent release of radiolabel-containing material was found from one of the polymers (a polyester urea-urethane, TDI/PCL/ED) which increased linearly up to 96 h. The polyether-containing polyurethanes showed no significant cell-mediated degradation under similar conditions as measured by radiolabel release. Scanning electron microscopy (SEM) showed that the cells adhered to the different polyurethanes. However, no effect of neutrophils on polymer structure could be detected by this technique. The cellular response to each polymer was evaluated by measuring release of elastase-like activity (ELA) into the tissue culture media. After 24h TDI/PCL/ED showed the highest levels of ELA in the tissue culture medium. When TDI/PCL/ED was incubated with commercial elastase in vitro, a significant release of radiolabel was found which was comparable to the amount of radiolabelled material released from this polymer in contact with the neutrophils in culture. No significant amount of radiolabel was released from the corresponding polyether material (TDI/PTMO/ED) under similar conditions.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- R S Labow
- Cardiovascular Devices Division, University of Ottawa Heart Institute, Ottawa Civic Hospital, ON, Canada
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Yoshida SH, Teuber SS, German JB, Gershwin ME. Immunotoxicity of silicone: implications of oxidant balance towards adjuvant activity. Food Chem Toxicol 1994; 32:1089-100. [PMID: 7959464 DOI: 10.1016/0278-6915(94)90150-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A variety of mechanisms can be proposed to explain the potential effects of silicone and silicone by-products on the immune response. In this paper, we discuss information on the chemistry of silicon and silicone gels/elastomers, and the manufacture of silicone breast implants as they pertain to the bioreactivity of silicone. Moreover, with reference to silicone-mediated human adjuvant disease, an overview of experimental adjuvant-induced arthritis is presented; comparisons with graft-versus-host disease and chemically induced autoimmunity then follow. Particular attention is paid to similarities in the characteristics of silicone and classic lipid adjuvants. For example, macrophage activation is presumed to be a central event in silicone-induced autoimmunity. Since those genes uniquely expressed in macrophages activated by plastic adherence are similar to those induced by lipopolysaccharide, adherence to silicone rubber may initiate an inflammatory response by the same mechanism. Macrophage effects would also include the erosion of implants through the generation of oxidants and localized pH changes. The degradation products of silicone are also implicated in the adjuvant effects of silicone implants. There is evidence to suggest that oxidants produced by inflammatory cells preferentially inactivate CD8+ suppressor T cells. This could then lead to an inflammatory state, perhaps through oxidant-induced transcription factors such as NF-kB, resulting in a long-term pro-oxidant imbalance that manifests itself as a breakdown in immunological self-tolerance. The authors hypothesize that autoreactivity following oxidant stress evolved to enhance inflammatory repair mechanisms after tissue, cell or molecular damage by oxidants.
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Affiliation(s)
- S H Yoshida
- Division of Rheumatology, Allergy and Clinical Immunology, School of Medicine, University of California, Davis 95616
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Frautschi JR, Chinn JA, Phillips RE, Zhao Q, Anderson JM, Joshi R, Levy RJ. Degradation of polyurethanes in vitro and in vitro: comparison of different models. Colloids Surf B Biointerfaces 1993. [DOI: 10.1016/0927-7765(93)80005-j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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