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Bakand S, Hayes A, Winder C, Khalil C, Markovic B. In vitro cytotoxicity testing of airborne formaldehyde collected in serum-free culture media. Toxicol Ind Health 2016; 21:147-54. [PMID: 16149729 DOI: 10.1191/0748233705th223oa] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The purpose of this study was to identify a suitable sampling model for on-site toxicity assessment of soluble air contaminants such as formaldehyde, a well known industrial and indoor air contaminant. The in vitro cytotoxicity of formaldehyde, the selected model for soluble air contaminants, was studied using the MTS (tetrazolium salt) assay in two carcinoma cell lines, A549 epithelial lung and HepG2 hepatocarcinoma, and in skin fibroblasts. The cytotoxic effects of airborne formaldehyde were evaluated using test atmospheres in concentrations below 10 ppm (12.3 mg/m3), generated by a dynamic diffusion method and bubbled (0.3 L/min) through serum-free culture media for one or four hours. Human cells were treated with formaldehyde air samples, and cell viability was determined after four hours incubation. In parallel, the concentration of airborne formaldehyde was monitored, using the 3500 NIOSH method. Cell viability of the HepG2 cells exposed to formaldehyde air samples (8.75 ppm-4 h) was reduced to less than 50% (31.69/1.24%). The HepG2 cell lines were found to be more sensitive (IC50=103.799/23.55 mg/L) to formaldehyde than both A549 cell lines (IC50=198.369/9.54 mg/L) and skin fibroblasts (IC50=196.689/36.73 mg/L) (PB/0.01). An average of 96.8% was determined for collection efficiency of formaldehyde in serum-free culture media. The results of this study suggest that absorption of soluble air contaminants, such as formaldehyde, in serum-free culture media can be used as a suitable sampling model for on-site toxicity assessments.
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Affiliation(s)
- S Bakand
- Chemical Safety and Applied Toxicology Laboratories, School of Safety Science, The University of New South Wales, Sydney 2052, Australia.
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Azzopardi D, Haswell LE, Foss-Smith G, Hewitt K, Asquith N, Corke S, Phillips G. Evaluation of an air-liquid interface cell culture model for studies on the inflammatory and cytotoxic responses to tobacco smoke aerosols. Toxicol In Vitro 2015; 29:1720-8. [PMID: 26096598 DOI: 10.1016/j.tiv.2015.06.016] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 05/16/2015] [Accepted: 06/08/2015] [Indexed: 11/22/2022]
Abstract
In vitro toxicological studies for tobacco product assessment have traditionally been undertaken using the particulate phase of tobacco smoke. However, this does not truly reflect exposure conditions that occur in smokers. Thus in vitro cell culture systems are required in which cells are exposed to tobacco whole smoke (WS) at the air-liquid interface (ALI). In this study bronchial epithelial cells were cultured on semi-permeable membranes, transitioned to the ALI and the robustness and sensitivity of the cells to tobacco WS and vapour phase (VP) assessed. Although no effect of air exposure was observed on cell viability, IL-6 and IL-8 release was increased. Exposure to WS resulted in a significant dose dependent decrease in cell viability and a significant non-dose dependent increase in inflammatory mediator secretion. The VP was found to contribute approximately 90% of the total cytotoxicity derived from WS. The cell culture system was also able to differentiate between two smoking regimens and was sensitive to passage number with increased inflammatory mediator secretion and lower cell viability observed in cell cultures of low passage number following WS exposure. This simple cell culture system may facilitate studies on the toxicological impact of future tobacco products and nicotine delivery devices.
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Affiliation(s)
- David Azzopardi
- British American Tobacco (Investments) Limited, Group R&D, Regents Park Road, Southampton SO15 8TL, UK
| | - Linsey E Haswell
- British American Tobacco (Investments) Limited, Group R&D, Regents Park Road, Southampton SO15 8TL, UK
| | - Geoff Foss-Smith
- British American Tobacco (Investments) Limited, Group R&D, Regents Park Road, Southampton SO15 8TL, UK
| | - Katherine Hewitt
- British American Tobacco (Investments) Limited, Group R&D, Regents Park Road, Southampton SO15 8TL, UK
| | - Nathan Asquith
- British American Tobacco (Investments) Limited, Group R&D, Regents Park Road, Southampton SO15 8TL, UK
| | - Sarah Corke
- British American Tobacco (Investments) Limited, Group R&D, Regents Park Road, Southampton SO15 8TL, UK
| | - Gary Phillips
- British American Tobacco (Investments) Limited, Group R&D, Regents Park Road, Southampton SO15 8TL, UK.
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Zimmermann R. Aerosols and health: a challenge for chemical and biological analysis. Anal Bioanal Chem 2015; 407:5863-7. [DOI: 10.1007/s00216-015-8832-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Eltzov E, Cohen A, Marks RS. Bioluminescent Liquid Light Guide Pad Biosensor for Indoor Air Toxicity Monitoring. Anal Chem 2015; 87:3655-61. [DOI: 10.1021/ac5038208] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Evgeni Eltzov
- The
Department of Biotechnology Engineering, Faculty of Engineering Science, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- School
of Material Science and Engineering, Nanyang Technology University, Nanyang Avenue, 639798, Singapore
| | - Avital Cohen
- The
Department of Biotechnology Engineering, Faculty of Engineering Science, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Robert S. Marks
- The
Department of Biotechnology Engineering, Faculty of Engineering Science, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- National
Institute of Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- The
Ilse Katz Center for Meso and Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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Hayes AJ, Bakand S. Toxicological perspectives of inhaled therapeutics and nanoparticles. Expert Opin Drug Metab Toxicol 2014; 10:933-47. [PMID: 24810077 DOI: 10.1517/17425255.2014.916276] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
INTRODUCTION The human respiratory system is an important route for the entry of inhaled therapeutics into the body to treat diseases. Inhaled materials may consist of gases, vapours, aerosols and particulates. In all cases, assessing the toxicological effect of inhaled therapeutics has many challenges. AREAS COVERED This article provides an overview of in vivo and in vitro models for testing the toxicity of inhaled therapeutics and nanoparticles implemented in drug delivery. Traditionally, inhalation toxicity has been performed on test animals to identify the median lethal concentration of airborne materials. Later maximum tolerable concentration denoted by LC0 has been introduced as a more ethically acceptable end point. More recently, in vitro methods have been developed, allowing the direct exposure of airborne material to cultured human target cells on permeable porous membranes at the air-liquid interface. EXPERT OPINION Modifications of current inhalation therapies, new pulmonary medications for respiratory diseases and implementation of the respiratory tract for systemic drug delivery are providing new challenges when conducting well-designed inhalation toxicology studies. In particular, the area of nanoparticles and nanocarriers is of critical toxicological concern. There is a need to develop toxicological test models, which characterise the toxic response and cellular interaction between inhaled particles and the respiratory system.
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Affiliation(s)
- Amanda J Hayes
- The University of New South Wales, School of Chemistry , UNSW Sydney, 2052 , Australia +61 403 028747 ; +61 2 9385 6141 ;
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Bohrn U, Stütz E, Fleischer M, Schöning MJ, Wagner P. Using a cell-based gas biosensor for investigation of adverse effects of acetone vapors in vitro. Biosens Bioelectron 2013; 40:393-400. [DOI: 10.1016/j.bios.2012.08.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Revised: 08/04/2012] [Accepted: 08/13/2012] [Indexed: 02/06/2023]
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Zimmermann R. Ambient aerosols and human health: working towards a combined analytical and toxicological approach. Anal Bioanal Chem 2011; 401:3041-4. [DOI: 10.1007/s00216-011-5456-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Bakand S, Hayes A. Troubleshooting methods for toxicity testing of airborne chemicals in vitro. J Pharmacol Toxicol Methods 2010; 61:76-85. [DOI: 10.1016/j.vascn.2010.01.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Revised: 01/18/2010] [Accepted: 01/20/2010] [Indexed: 01/01/2023]
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Grainger C, Greenwell L, Martin G, Forbes B. The permeability of large molecular weight solutes following particle delivery to air-interfaced cells that model the respiratory mucosa. Eur J Pharm Biopharm 2009; 71:318-24. [DOI: 10.1016/j.ejpb.2008.09.006] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 09/03/2008] [Accepted: 09/13/2008] [Indexed: 11/27/2022]
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Bakand S, Winder C, Khalil C, Hayes A. Toxicity Assessment of Industrial Chemicals and Airborne Contaminants: Transition fromIn VivotoIn VitroTest Methods: A Review. Inhal Toxicol 2008; 17:775-87. [PMID: 16195213 DOI: 10.1080/08958370500225240] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Exposure to occupational and environmental contaminants is a major contributor to human health problems. Inhalation of gases, vapors, aerosols, and mixtures of these can cause a wide range of adverse health effects, ranging from simple irritation to systemic diseases. Despite significant achievements in the risk assessment of chemicals, the toxicological database, particularly for industrial chemicals, remains limited. Considering there are approximately 80,000 chemicals in commerce, and an extremely large number of chemical mixtures, in vivo testing of this large number is unachievable from both economical and practical perspectives. While in vitro methods are capable of rapidly providing toxicity information, regulatory agencies in general are still cautious about the replacement of whole-animal methods with new in vitro techniques. Although studying the toxic effects of inhaled chemicals is a complex subject, recent studies demonstrate that in vitro methods may have significant potential for assessing the toxicity of airborne contaminants. In this review, current toxicity test methods for risk evaluation of industrial chemicals and airborne contaminants are presented. To evaluate the potential applications of in vitro methods for studying respiratory toxicity, more recent models developed for toxicity testing of airborne contaminants are discussed.
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Affiliation(s)
- S Bakand
- Chemical Safety and Applied Toxicology (CSAT) Laboratories, School of Safety Science, University of New South Wales, Sydney, Australia.
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Bakand S, Winder C, Hayes A. Comparative in vitro cytotoxicity assessment of selected gaseous compounds in human alveolar epithelial cells. Toxicol In Vitro 2007; 21:1341-7. [PMID: 17574383 DOI: 10.1016/j.tiv.2007.04.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Revised: 04/04/2007] [Accepted: 04/23/2007] [Indexed: 01/11/2023]
Abstract
Exposure to airborne contaminants is significantly associated with human health risks, ranging from bronchial reactivity to morbidity and mortality due to acute intense or long term low level repeated exposures. However, the precise mechanisms that derive such effects are not always understood. Although inhalation studies are technologically complicated, correct hazard characterisation is essential for comparable risk assessment of inhaled materials. The aim of this study was to investigate the comparative in vitro cytotoxicity of selected gaseous contaminants in human lung cells. The cytotoxicity of nitrogen dioxide (NO(2)), sulphur dioxide (SO(2)) and ammonia (NH(3)) was investigated in A549- human pulmonary type II-like epithelial cell lines cultured on porous membranes in Snapwell inserts. A dynamic direct exposure method was established by utilizing the horizontal diffusion chamber system (Harvard Apparatus Inc, USA) for delivery of test atmospheres. Test atmospheres were generated using a dynamic direct dilution method and the concentration monitored by appropriate analytical methods. A diversified battery of in vitro assays including the MTS (tetrazolium salt; Promega), NRU (neutral red uptake; Sigma) and ATP (adenosine triphosphate; Promega) assays was implemented. Airborne IC(50) (50% inhibitory concentration) values were calculated based on the most sensitive assay for each test gas including NO(2) (IC(50)=11+/-3.54 ppm; NRU)>SO(2) (IC(50)=48+/-2.83 ppm; ATP)> and NH(3) (IC(50)=199+/-1.41 ppm; MTS). However, all in vitro assays revealed similar toxicity ranking for selected gaseous contaminants. Identical toxicity ranking was achieved using both in vitro and published in vivo data. This comparison suggests that results of in vitro methods are comparable to in vivo data and may provide greater sensitivity for respiratory toxicity studies of gaseous contaminants.
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Affiliation(s)
- S Bakand
- Chemical Safety and Applied Toxicology (CSAT) Laboratories, School of Safety Science, The University of New South Wales, UNSW Sydney 2052, Australia
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Bitterle E, Karg E, Schroeppel A, Kreyling WG, Tippe A, Ferron GA, Schmid O, Heyder J, Maier KL, Hofer T. Dose-controlled exposure of A549 epithelial cells at the air-liquid interface to airborne ultrafine carbonaceous particles. CHEMOSPHERE 2006; 65:1784-90. [PMID: 16762398 DOI: 10.1016/j.chemosphere.2006.04.035] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2005] [Revised: 04/03/2006] [Accepted: 04/11/2006] [Indexed: 05/10/2023]
Abstract
The geometry of commercially available perfusion chambers designed for harbouring three membrane-based cell cultures was modified for reliable and dose-controlled air-liquid interface (ALI) exposures. Confluent A549 epithelial cells grown on membranes were integrated in the chamber system and supplied with medium from the chamber bottom. Cell viability was not impaired by the conditions of ALI exposure without particles. Expression of the inflammatory cytokines interleukin 6 and interleukin 8 by A549 cells during ALI exposure to filtered air for 6h and subsequent stimulation with tumor necrosis factor was not altered compared to submersed controls, indicating that the cells maintained their functional integrity. Ultrafine carbonaceous model particles with a count median mobility diameter of about 95+/-5 nm were produced by spark discharge at a stable concentration of about 2 x 10(6) cm(-3) and continuously monitored for accurate determination of the exposure dose. Delivery to the ALI exposure system yielded a homogeneous particle deposition over the membranes with a deposition efficiency of 2%. Mid dose exposure of A549 cells to this aerosol for 6h yielded a total particle deposition of (2.6+/-0.4) x 10(8) cm(-2) corresponding to (87+/-23) ng cm(-2). The 2.7-fold (p < or = 0.05) increased transcription of heme oxygenase-1 indicated a sensitive antioxidant and stress response, while cell viability did not reveal a toxic mechanism.
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Affiliation(s)
- E Bitterle
- GSF National Research Center for Environment and Health, Institute for Inhalation Biology, Ingolstaedter Landstr. 1, D-85764 Neuherberg/Munich, Germany
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Bakand S, Winder C, Khalil C, Hayes A. An experimental in vitro model for dynamic direct exposure of human cells to airborne contaminants. Toxicol Lett 2006; 165:1-10. [PMID: 16488094 DOI: 10.1016/j.toxlet.2006.01.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2005] [Revised: 01/16/2006] [Accepted: 01/16/2006] [Indexed: 11/18/2022]
Abstract
The aim of this study was to establish a dynamic in vitro model for direct exposure of human cells to gaseous contaminants to investigate the cellular responses to airborne chemical exposures. Nitrogen dioxide (NO2) was selected as a model gas compound. Standard test atmospheres were generated (2.5-10 ppm), using a dynamic direct dilution method. Human cells including: A549 pulmonary type II-like epithelial cell lines and skin fibroblasts were grown on porous membranes. Human cells on snapwell inserts were placed in horizontal diffusion chambers and exposed to various airborne concentrations of NO2 directly at the air/liquid interface for 1 h at 37 degrees C. Cytotoxicity of the test gas was investigated using the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium), NRU (neutral red uptake) and ATP (Adenosine triphosphate) assays. Dose-dependent effects of NO2 were observed in human cells tested which resulted in a significant reduction of cell viability at concentrations normally encountered in workplace environments (p<0.05). Our findings suggest that the dynamic direct exposure method can be used for in vitro inhalational and dermal toxicity studies and potentially as an advanced technology for biomonitoring of airborne contaminants in future occupational and environmental toxicity assessments.
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Affiliation(s)
- S Bakand
- Chemical Safety and Applied Toxicology (CSAT) Laboratories, School of Safety Science, The University of New South Wales, UNSW Sydney 2052, Australia.
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Bakand S, Winder C, Khalil C, Hayes A. A novel in vitro exposure technique for toxicity testing of selected volatile organic compounds. ACTA ACUST UNITED AC 2006; 8:100-5. [PMID: 16395465 DOI: 10.1039/b509812b] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Exposure to vapours of volatile chemicals is a major occupational and environmental health concern. Toxicity testing of volatile organic compounds (VOCs) has always faced significant technological problems due to their high volatility and/or low solubility. The aim of this study was to develop a practical and reproducible in vitro exposure technique for toxicity testing of VOCs. Standard test atmospheres of xylene and toluene were generated in glass chambers using a static method. Human cells including: A549-lung derived cell lines, HepG2-liver derived cell lines and skin fibroblasts, were grown in porous membranes and exposed to various airborne concentrations of selected VOCs directly at the air/liquid interface for 1 h at 37 degrees C. Cytotoxicity of test chemicals was investigated using the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) and NRU (neutral red uptake) assays following 24 h incubation. Airborne IC(50) (50% inhibitory concentration) values were determined using dose response curves for xylene (IC(50)=5350+/- 328 ppm, NRU; IC(50)=5750+/- 433 ppm, MTS in skin fibroblast) and toluene (IC(50)=0 500+/- 527 ppm, NRU; IC(50)=11,200 +/- 1,044 ppm, MTS in skin fibroblast). Our findings suggest that static direct exposure at the air/liquid interface is a practical and reproducible technique for toxicity testing of VOCs. Further, this technique can be used for inhalational and dermal toxicity studies of volatile chemicals in vitro as the exposure pattern in vivo is closely simulated by this method.
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Affiliation(s)
- S Bakand
- Chemical Safety and Applied Toxicology (CSAT) Laboratories, School of Safety Science, The University of New South Wales, UNSW, Sydney, 2052, Australia
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Wichmann G, Mühlenberg J, Fischäder G, Kulla C, Rehwagen M, Herbarth O, Lehmann I. An experimental model for the determination of immunomodulating effects by volatile compounds. Toxicol In Vitro 2005; 19:685-93. [PMID: 15885978 DOI: 10.1016/j.tiv.2005.03.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2004] [Revised: 01/17/2005] [Accepted: 03/17/2005] [Indexed: 10/25/2022]
Abstract
An in vitro exposure system was developed to enable simultaneous exposure of primary cells or cell lines to defined concentrations of volatile organic compounds (VOC) without the necessity of a constant-flow exposure system. Toluene was used as model VOC and administered via the gas phase. CD3/CD28-stimulated human peripheral blood mononuclear cells (PBMC) were used as indicator cells. Vitality/proliferation of PBMC was tested using the MTT assay and their functional reactivity using cytokine ELISA for interferon-gamma (IFN-gamma), interleukin-4 (IL-4), IL-13, and tumor-necrosis-factor-alpha (TNF-alpha). Chemical analysis using headspace gas chromatography confirmed that this new method guaranties reproducible VOC exposure (R2 = 0.995 for the correlation between external toluene concentration and toluene in the cell culture). While cytotoxic effects were not observed, dose-dependent toluene effects on functional reactivity of PBMC were found. The secretion of IFN-gamma, IL-4, and IL-13 was inhibited at concentrations of 72.5 g/m3 and above, whereas the TNF-alpha production was increased. Since the presented in vitro model ensures toluene exposure in concentrations comparable to the real situation, and allows the investigation of dose-dependent immunomodulatory toluene effects in concentrations without cytotoxicity, this method first described here is introduced as useful tool in analysis of VOC-triggered effects on immune cells.
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Affiliation(s)
- Gunnar Wichmann
- Department of Environmental Immunology, UFZ Centre for Environmental Research Leipzig-Halle Ltd., Permoserstrasse 15, 04318 Leipzig, Germany.
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Sexton KG, Jeffries HE, Jang M, Kamens RM, Doyle M, Voicu I, Jaspers I. Photochemical products in urban mixtures enhance inflammatory responses in lung cells. Inhal Toxicol 2004; 16 Suppl 1:107-14. [PMID: 15204799 DOI: 10.1080/08958370490443196] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Complex urban air mixtures that realistically mimic urban smog can be generated for investigating adverse health effects. "Smog chambers" have been used for over 30 yr to conduct experiments for developing and testing photochemical models that predict ambient ozone (O(3)) concentrations and aerosol chemistry. These chambers were used to generate photochemical and nonirradiated systems, which were interfaced with an in vitro exposure system to compare the inflammatory effects of complex air pollutant mixtures with and without sunlight-driven chemistry. These are preliminary experiments in a new project to study the health effects of particulate matter and associated gaseous copollutants. Briefly, two matched outdoor chambers capable of using real sunlight were utilized to generate two test atmospheres for simultaneous exposures to cultured lung cells. One chamber was used to produce a photochemically active system, which ran from sunrise to sunset, producing O(3) and the associated secondary products. A few hours after sunset, NO was added to titrate and remove completely the O(3), forming NO(2). In the second chamber, an equal amount of NO(2) and the same amount of the 55-component hydrocarbon mixture used to setup the photochemical system in the first side were injected. A549 cells, from an alveolar type II-like cell line grown on membranous support, were exposed to the photochemical mixture or the "original" NO(2)/hydrocarbon mixture for 5 h and analyzed for inflammatory response (IL-8 mRNA levels) 4 h postexposure. In addition, a variation of this experiment was conducted to compare the photochemical system producing O(3) and NO(2), with a simple mixture of only the O(3) and NO(2). Our data suggest that the photochemically altered mixtures that produced secondary products induced about two- to threefold more IL-8 mRNA than the mixture of NO(2) and hydrocarbons or O(3). These results indicate that secondary products generated through the photochemical reactions of NO(x) and hydrocarbons may significantly contribute to the inflammatory responses induced by exposure to urban smog. From previous experience with relevant experiments, we know that many of these gaseous organic products would contribute to the formation of significant secondary organic particle mass in the presence of seed particles (including road dust or combustion products). In the absence of such particles, these gaseous products remained mostly as gases. These experiments show that photochemically produced gaseous products do influence the toxic responses of the cells in the absence of particles.
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Affiliation(s)
- Kenneth G Sexton
- Department of Environmental Science and Engineering, University of North Carolina at Chapel Hill, 27599, USA.
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Aufderheide M, Knebel JW, Ritter D. An improved in vitro model for testing the pulmonary toxicity of complex mixtures such as cigarette smoke. EXPERIMENTAL AND TOXICOLOGIC PATHOLOGY : OFFICIAL JOURNAL OF THE GESELLSCHAFT FUR TOXIKOLOGISCHE PATHOLOGIE 2003; 55:51-7. [PMID: 12940629 DOI: 10.1078/0940-2993-00298] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Numerous approaches have been employed for testing the biological activity of cigarette smoke in vitro. None of them has managed to expose cultured lung cells in a realistic manner to the complex gaseous and particulate mixture that constitutes cigarette smoke. We have devised a system that makes this possible. The system presented here enables the direct exposure of human lung cells to native, unmodified cigarette mainstream smoke. It consists of a smoking machine, a dilution device for the smoke, analytical devices for online monitoring and a specially adapted exposure module based on the Cultex** cell cultivation system that is equipped with a gas-exposure top. Due to the special design of the exposure device and the optimised exposure conditions, this equipment allows cultured human lung cells to be exposed to freshly generated cigarette mainstream smoke. Exploratory experiments revealed that the smoke could be diluted over a wide concentration range in a reproducible way with respect to gas and particulate phases, and also demonstrated reproducible particle deposition depending on smoke concentration. Furthermore, it was shown that the exposed cells maintained their viability. Native cigarette mainstream smoke induced dose-dependent cellular effects in exposed cells with respect to cellular viability (viable cell number monitored by tetrazolium salt cleavage) and intracellular parameters (ATP and glutathione content). Therefore, fresh, physically and chemically unmodified cigarette mainstream smoke can be tested using this novel system.
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Affiliation(s)
- Michaela Aufderheide
- Department of In Vitro Toxicology, Fraunhofer Institute of Toxicology and Experimental Medicine, Hannover, Germany.
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Abstract
The in vitro study of adverse cellular effects induced by inhaled pollutants poses a special problem due to the difficulties of exposing cultured cells of the respiratory tract directly to test atmospheres that can include complex gaseous and particulate mixtures. In general, there is no widely accepted in vitro exposure system. However, in vitro methods offer the unique possibility for use of human cells, developed and validated cell culture and exposure device (CULTEX(1)) using the principle of the air/liquid exposure technique. Cells of the respiratory tract are grown on porous membranes in transwell inserts. After removal of the medium, the cells can be treated on their superficial surfaces with the test atmosphere, and at the same time they are supplied with nutrients through the membrane below. In comparison with other experimental approaches, the goal of our studies is to analyze the biological effects of test atmospheres under environmental conditions, i.e. without humidifying the atmosphere or adding additional CO(2). The system used is small and flexible enough independent of a cultivation chamber and thus offers the opportunity for onsite study of indoor and outdoor atmospheres in the field. The efficacy of the exposure device has already been demonstrated in the analysis of dose-dependent cytotoxic and genotoxic effects of exposure of epithelial lung cells to complex mixtures such as native diesel exhaust and side-stream smoke.
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Affiliation(s)
- Michaela Aufderheide
- Fraunhofer Institute of Toxicology and Aerosol Research, Drug Research and Clinical Inhalation, Nikolai-Fuchs-Strasse 1, 30625, Hannover, Germany.
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Aufderheide M, Knebel JW, Ritter D. A method for the in vitro exposure of human cells to environmental and complex gaseous mixtures: application to various types of atmosphere. Altern Lab Anim 2002; 30:433-41. [PMID: 12234248 DOI: 10.1177/026119290203000406] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The application of in vitro methods to the analysis of the effects of airborne materials is still limited, because there are no generally accepted concepts and technologies for efficiently exposing adherent growing cells to test atmospheres, especially those comprising complex mixtures of gaseous and particulate phases. The introduction of in vitro research into the field of inhalation toxicology offers a unique possibility for using human cells and tissues for pre-screening studies, thus reducing the necessity for animal experiments, and cutting the numbers of animals used in toxicological testing. We therefore developed a novel experimental concept that uses an exposure device based on the cell cultivation system CULTEX (Patent No. DE 198011763; PCT/EP99/00295). This allowed us to investigate environmental atmospheres, which were chemically and physically unmodified, in an in vitro system, by exposing the target cells directly at the air/liquid interface. The exposure device itself is small and flexible enough to be connected to a variety of aerosol-generating systems without the need for an incubator, as it fulfils all the requirements for maintaining cell viability over a defined period. The general applicability and the sensitivity of this in vitro approach for testing various generated atmospheres under the same cell-exposure conditions were demonstrated by studying dose-dependent cytotoxic effects in human lung epithelial cells exposed to air contaminated with single gases or complex mixtures, such as diesel exhaust fumes and side-stream cigarette smoke.
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Affiliation(s)
- Michaela Aufderheide
- Department of In Vitro Toxicology, Fraunhofer Institute of Toxicology and Aerosol Research, Pharmacology and Clinical Inhalation, Nikdai-Fuchs-Strasse 1, 30625 Hannover, Germany
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Knebel JW, Ritter D, Aufderheide M. Exposure of human lung cells to native diesel motor exhaust--development of an optimized in vitro test strategy. Toxicol In Vitro 2002; 16:185-92. [PMID: 11869881 DOI: 10.1016/s0887-2333(01)00110-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
To investigate the effects of native diesel motor exhaust on human lung cells in vitro, a new experimental concept was developed using an exposure device on the base of the cell cultivation system CULTEX (Patent No. DE19801763.PCT/EP99/00295) to handle the cells during a 1-h exposure period independent of an incubator and next to an engine test rig. The final experimental set-up allows the investigation of native (chemically and physically unmodified) diesel exhaust using short distances for the transportation of the gas to the target cells. The analysis of several atmospheric compounds as well as the particle concentration of the exhaust was performed by online monitoring in parallel. To validate the complete system we concentrated on the measurement of two distinct viability parameters after exposure to air and undiluted, diluted and filtered diesel motor exhaust generated under different engine operating conditions. Cell viability was not influenced by the exposure to clean air, whereas dose-dependent cytotoxicity was found contingent on the dosage of exhaust. Additionally, the quality of exhaust, represented by two engine operating conditions (idling, higher load), also showed well-distinguishable cytotoxicity. In summary, the experimental set-up allows research on biological effects of native engine emissions using short exposure times.
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Affiliation(s)
- J W Knebel
- Fraunhofer Institute of Toxicology and Aerosol Research, Nikolai-Fuchs Str. 1, 30625 Hannover, Germany
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Ritter D, Knebel JW, Aufderheide M. In vitro exposure of isolated cells to native gaseous compounds--development and validation of an optimized system for human lung cells. EXPERIMENTAL AND TOXICOLOGIC PATHOLOGY : OFFICIAL JOURNAL OF THE GESELLSCHAFT FUR TOXIKOLOGISCHE PATHOLOGIE 2001; 53:373-86. [PMID: 11817107 DOI: 10.1078/0940-2993-00204] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
An exposure system for adherent growing cells to native gaseous compounds was developed using air/liquid culture techniques on the basis of the Cultex system'. In contrast to other exposure systems the reproducible testing of native environmentally relevant gases without changing their physical or chemical properties including heating, CO2- content and humidity is possible. Specially designed systems for medium flow and gas support guarantee the nutrification and humidification as well as the direct gas contact of the exposed cells which are cultivated on microporous membranes (0.4 microm pore size). The system works independently of a cell culture incubator offering the possibility to analyze any relevant gas mixture directly under indoor or outdoor conditions. Several experimental approaches were carried out to characterize the properties of the system. In exploratory experiments without cells, the reproducibility and quality of the gas/membrane contact could be demonstrated. Exposures of human lung fibroblasts (Lk004 cells) and human lung epithelial cells (HFBE-21 cells) to synthetic air, ozone (202 ppb, 510 ppb) and nitrogen dioxide (75 ppb to 1,200 ppb) established that cells could be treated for 120 minutes without significant loss of cellular viability. At the same time, the experiments confirmed that such exposure times are long enough to detect biological effects of environmentally relevant gas mixtures. The analysis of viability (viable cell number, tetrazoliumsalt cleavage) and intracellular end-points (oxidized/reduced glutathione, ATP/ADP) showed that both gases induced relevant cellular changes. In summary, the efficiency and practicability of this newly developed exposure system for adherent human lung cells could be clearly demonstrated.
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Affiliation(s)
- D Ritter
- Department In Vitro Toxicology, Fraunhofer Institute for Toxicology and Aerosol Research, Hannover, Germany
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