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Nicol B, Vandenbossche-Goddard E, Thorpe C, Newman R, Patel H, Yates D. A workflow to practically apply true dose considerations to in vitro testing for next generation risk assessment. Toxicology 2024; 505:153826. [PMID: 38719068 DOI: 10.1016/j.tox.2024.153826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 04/22/2024] [Accepted: 05/01/2024] [Indexed: 05/14/2024]
Abstract
With the move away from safety testing assessment based on data generated in experimental animals the concept of Next Generation Risk Assessment (NGRA) has arisen which instead uses data from in silico and in vitro models. A key uncertainty in risk assessment is the actual dose of test chemical at the target site, and therefore surrogate dose metrics, such as nominal concentration in test media are used to describe in vitro effect (or no-effect) doses. The reliability and accuracy of the risk assessment therefore depends largely on our ability to understand and characterise the relationship between the dose metrics used and the actual biologically effective dose at the target site. The objective of this publication is to use 40 case study chemicals to illustrate how in vitro dose considerations can be applied to characterise the "true dose" and build confidence in the understanding of the biologically effective dose in in vitro test systems for the determination e.g. points of departure (PoDs) for NGRA. We propose a workflow that can be applied to assess whether the nominal test concentration can be considered a conservative dose metric for use in NGRA. The workflow examines the implications of volatility, stability, hydrophobicity, binding to plastic and serum, solubility, and the potential use of in silico models for some of these parameters. For the majority of the case study chemicals we found that the use of nominal concentrations in risk assessment would result in conservative decision making. However, for serval chemicals a potential for underestimation of the risk in humans in vivo based on in vitro nominal effect concentrations was identified, and approaches for refinement by characterisation of the actual effect concentration are proposed.
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Affiliation(s)
- Beate Nicol
- Unilever Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedford, Bedfordshire MK44 1LQ, UK
| | - Evita Vandenbossche-Goddard
- Unilever Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedford, Bedfordshire MK44 1LQ, UK.
| | - Charlotte Thorpe
- Unilever Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedford, Bedfordshire MK44 1LQ, UK
| | | | - Hiral Patel
- Charles River Laboratories, Cambridgeshire CB10 1XL, UK
| | - Dawn Yates
- Charles River Laboratories, Cambridgeshire CB10 1XL, UK
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2
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Silva AC, Loizou GD, McNally K, Osborne O, Potter C, Gott D, Colbourne JK, Viant MR. A novel method to derive a human safety limit for PFOA by gene expression profiling and modelling. FRONTIERS IN TOXICOLOGY 2024; 6:1368320. [PMID: 38577564 PMCID: PMC10991825 DOI: 10.3389/ftox.2024.1368320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 03/01/2024] [Indexed: 04/06/2024] Open
Abstract
Perfluorooctanoic acid (PFOA) is a persistent environmental contaminant that can accumulate in the human body due to its long half-life. This substance has been associated with liver, pancreatic, testicular and breast cancers, liver steatosis and endocrine disruption. PFOA is a member of a large group of substances also known as "forever chemicals" and the vast majority of substances of this group lack toxicological data that would enable their effective risk assessment in terms of human health hazards. This study aimed to derive a health-based guidance value for PFOA intake (ng/kg BW/day) from in vitro transcriptomics data. To this end, we developed an in silico workflow comprising five components: (i) sourcing in vitro hepatic transcriptomics concentration-response data; (ii) deriving molecular points of departure using BMDExpress3 and performing pathway analysis using gene set enrichment analysis (GSEA) to identify the most sensitive molecular pathways to PFOA exposure; (iii) estimating freely-dissolved PFOA concentrations in vitro using a mass balance model; (iv) estimating in vivo doses by reverse dosimetry using a PBK model for PFOA as part of a quantitative in vitro to in vivo extrapolation (QIVIVE) algorithm; and (v) calculating a tolerable daily intake (TDI) for PFOA. Fourteen percent of interrogated genes exhibited in vitro concentration-response relationships. GSEA pathway enrichment analysis revealed that "fatty acid metabolism" was the most sensitive pathway to PFOA exposure. In vitro free PFOA concentrations were calculated to be 2.9% of the nominal applied concentrations, and these free concentrations were input into the QIVIVE workflow. Exposure doses for a virtual population of 3,000 individuals were estimated, from which a TDI of 0.15 ng/kg BW/day for PFOA was calculated using the benchmark dose modelling software, PROAST. This TDI is comparable to previously published values of 1.16, 0.69, and 0.86 ng/kg BW/day by the European Food Safety Authority. In conclusion, this study demonstrates the combined utility of an "omics"-derived molecular point of departure and in silico QIVIVE workflow for setting health-based guidance values in anticipation of the acceptance of in vitro concentration-response molecular measurements in chemical risk assessment.
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Affiliation(s)
- Arthur de Carvalho e Silva
- School of Biosciences, University of Birmingham, Birmingham, United Kingdom
- Centre for Environmental Research and Justice (CERJ), University of Birmingham, Birmingham, United Kingdom
| | | | | | - Olivia Osborne
- Science Evidence and Research Division, Food Standards Agency, London, United Kingdom
| | - Claire Potter
- Science Evidence and Research Division, Food Standards Agency, London, United Kingdom
| | - David Gott
- Science Evidence and Research Division, Food Standards Agency, London, United Kingdom
| | - John K. Colbourne
- School of Biosciences, University of Birmingham, Birmingham, United Kingdom
- Centre for Environmental Research and Justice (CERJ), University of Birmingham, Birmingham, United Kingdom
| | - Mark R. Viant
- School of Biosciences, University of Birmingham, Birmingham, United Kingdom
- Centre for Environmental Research and Justice (CERJ), University of Birmingham, Birmingham, United Kingdom
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3
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Forouz F, Mohammed Y, Shobeiri Nejad HSA, Roberts MS, Grice JE. In vitro screening of topical formulation excipients for epithelial toxicity in cancerous and non-cancerous cell lines. EXCLI JOURNAL 2023; 22:1173-1199. [PMID: 38204966 PMCID: PMC10776879 DOI: 10.17179/excli2023-6072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 10/11/2023] [Indexed: 01/12/2024]
Abstract
Chemical excipients used in topical formulations may be toxic to living skin cells. Here, we compared the in vitro toxicity of some common solubilizing excipients against human melanoma cells, human keratinocytes (HaCaT) and primary skin fibroblasts (FB) as examples of cancerous, immortalized and primary human skin cells, often used as experimental models representative of in vivo conditions. Two distinct endpoint assays (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and crystal violet (CV)) were used. The mechanism of cell death after excipient exposure was assessed through Reactive Oxygen Species (ROS) production, cell membrane integrity and cell cycle progression. Results showed that the surfactants, Labrasol®, Labrafil® and Transcutol®, were less toxic than Triton X-100 (a model irritant) in all cell types whereas the oil, Labrafac®, was non-toxic. The human melanoma WM164 cell line showed the greatest sensitivity toward cytotoxicity after chemical exposure, while the other cell lines were more resistant. The relative excipient cytotoxicity responses observed in the MTT and CV assays were comparable and similar trends were seen in their estimated 50 % inhibitory concentration (IC50) values. DNA fragmentation by flow cytometry after exposing the cells to IC50 concentrations of the excipients showed negligible apoptotic populations. ROS production was increased in all cell types after toxic exposure; however, ROS elevation did not lead to apoptosis. The toxicity profiles of each excipient are not only relevant to their use in formulating safe topical products but also in the potential synergistic efficacy in the topical treatment of melanoma.
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Affiliation(s)
- Farzaneh Forouz
- Therapeutics Research Group, Frazer Institute, The University of Queensland, Woolloongabba, QLD 4102, Australia
- School of Pharmacy, The University of Queensland, Woolloongabba, QLD 4102, Australia
| | - Yousuf Mohammed
- Therapeutics Research Group, Frazer Institute, The University of Queensland, Woolloongabba, QLD 4102, Australia
- School of Pharmacy, The University of Queensland, Woolloongabba, QLD 4102, Australia
| | | | - Michael S. Roberts
- Therapeutics Research Group, Frazer Institute, The University of Queensland, Woolloongabba, QLD 4102, Australia
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA 5000, Australia
- Therapeutics Research Centre, Basil Hetzel Institute for Translational Medical Research, The Queen Elizabeth Hospital, Woodville, SA 5011, Adelaide, Australia
| | - Jeffrey E. Grice
- Therapeutics Research Group, Frazer Institute, The University of Queensland, Woolloongabba, QLD 4102, Australia
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4
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Loizou G, McNally K, Paini A, Hogg A. Derivation of a Human In Vivo Benchmark Dose for Bisphenol A from ToxCast In Vitro Concentration Response Data Using a Computational Workflow for Probabilistic Quantitative In Vitro to In Vivo Extrapolation. Front Pharmacol 2022; 12:754408. [PMID: 35222005 PMCID: PMC8874249 DOI: 10.3389/fphar.2021.754408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 11/15/2021] [Indexed: 11/23/2022] Open
Abstract
A computational workflow which integrates physiologically based kinetic (PBK) modelling; global sensitivity analysis (GSA), Approximate Bayesian Computation (ABC), Markov Chain Monte Carlo (MCMC) simulation and the Virtual Cell Based Assay (VCBA) for the estimation of the active, free in vitro concentration of chemical in the reaction medium was developed to facilitate quantitative in vitro to in vivo extrapolation (QIVIVE). The workflow was designed to estimate parameter and model uncertainty within a computationally efficient framework. The workflow was tested using a human PBK model for bisphenol A (BPA) and high throughput screening (HTS) in vitro concentration-response data, for estrogen and pregnane X receptor activation determined in human liver and kidney cell lines, from the ToxCast/Tox21 database. In vivo benchmark dose 10% lower confidence limits (BMDL10) for oral uptake of BPA (ng/kg BW/day) were calculated from the in vivo dose-responses and compared to the human equivalent dose (HED) BMDL10 for relative kidney weight change in the mouse derived by European Food Safety Authority (EFSA). Three from four in vivo BMDL10 values calculated in this study were similar to the EFSA values whereas the fourth was much smaller. The derivation of an uncertainty factor (UF) to accommodate the uncertainties associated with measurements using human cell lines in vitro, extrapolated to in vivo, could be useful for the derivation of Health Based Guidance Values (HBGV).
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Affiliation(s)
- George Loizou
- Health and Safety Executive, Harpur Hill, Buxton, United Kingdom
- *Correspondence: George Loizou,
| | - Kevin McNally
- Health and Safety Executive, Harpur Hill, Buxton, United Kingdom
| | - Alicia Paini
- European Commission Joint Research Centre, Ispra, Italy
| | - Alex Hogg
- Health and Safety Executive, Harpur Hill, Buxton, United Kingdom
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5
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Thakuri A, Banerjee M, Chatterjee A. Sulfonate‐Functionalized AIEgens: Strategic Approaches Beyond Water Solubility for Sensing and Imaging Applications. CHEMPHOTOCHEM 2022. [DOI: 10.1002/cptc.202100234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Ankit Thakuri
- Department of Chemistry BITS-Pilani, KK Birla Goa Campus NH 17B, Bypass Road, Zuarinagar Sancoale Goa 403726 India
| | - Mainak Banerjee
- Department of Chemistry BITS-Pilani, KK Birla Goa Campus NH 17B, Bypass Road, Zuarinagar Sancoale Goa 403726 India
| | - Amrita Chatterjee
- Department of Chemistry BITS-Pilani, KK Birla Goa Campus NH 17B, Bypass Road, Zuarinagar Sancoale Goa 403726 India
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6
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Armitage JM, Sangion A, Parmar R, Looky AB, Arnot JA. Update and Evaluation of a High-Throughput In Vitro Mass Balance Distribution Model: IV-MBM EQP v2.0. TOXICS 2021; 9:toxics9110315. [PMID: 34822706 PMCID: PMC8625852 DOI: 10.3390/toxics9110315] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 11/15/2021] [Accepted: 11/17/2021] [Indexed: 11/16/2022]
Abstract
This study demonstrates the utility of an updated mass balance model for predicting the distribution of organic chemicals in in vitro test systems (IV-MBM EQP v2.0) and evaluates its performance with empirical data. The IV-MBM EQP v2.0 tool was parameterized and applied to four independent data sets with measured ratios of bulk medium or freely-dissolved to initial nominal concentrations (e.g., C24/C0 where C24 is the measured concentration after 24 h of exposure and C0 is the initial nominal concentration). Model performance varied depending on the data set, chemical properties (e.g., "volatiles" vs. "non-volatiles", neutral vs. ionizable organics), and model assumptions but overall is deemed acceptable. For example, the r2 was greater than 0.8 and the mean absolute error (MAE) in the predictions was less than a factor of two for most neutral organics included. Model performance was not as good for the ionizable organic chemicals included but the r2 was still greater than 0.7 and the MAE less than a factor of three. The IV-MBM EQP v2.0 model was subsequently applied to several hundred chemicals on Canada's Domestic Substances List (DSL) with nominal effects data (AC50s) reported for two in vitro assays. We report the frequency of chemicals with AC50s corresponding to predicted cell membrane concentrations in the baseline toxicity range (i.e., >20-60 mM) and tabulate the number of chemicals with "volatility issues" (majority of chemical in headspace) and "solubility issues" (freely-dissolved concentration greater than water solubility after distribution). In addition, the predicted "equivalent EQP blood concentrations" (i.e., blood concentration at equilibrium with predicted cellular concentration) were compared to the AC50s as a function of hydrophobicity (log octanol-water partition or distribution ratio). The predicted equivalent EQP blood concentrations exceed the AC50 by up to a factor of 100 depending on hydrophobicity and assay conditions. The implications of using AC50s as direct surrogates for human blood concentrations when estimating the oral equivalent doses using a toxicokinetic model (i.e., reverse dosimetry) are then briefly discussed.
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Affiliation(s)
- James M. Armitage
- AES Armitage Environmental Sciences, Inc., Ottawa, ON K1L 8C3, Canada
- Correspondence:
| | - Alessandro Sangion
- ARC Arnot Research and Consulting, Inc., Toronto, ON M4M 1W4, Canada; (A.S.); (R.P.); (A.B.L.); (J.A.A.)
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, ON M1C 1A4, Canada
| | - Rohan Parmar
- ARC Arnot Research and Consulting, Inc., Toronto, ON M4M 1W4, Canada; (A.S.); (R.P.); (A.B.L.); (J.A.A.)
| | - Alexandra B. Looky
- ARC Arnot Research and Consulting, Inc., Toronto, ON M4M 1W4, Canada; (A.S.); (R.P.); (A.B.L.); (J.A.A.)
| | - Jon A. Arnot
- ARC Arnot Research and Consulting, Inc., Toronto, ON M4M 1W4, Canada; (A.S.); (R.P.); (A.B.L.); (J.A.A.)
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, ON M1C 1A4, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada
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7
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Abd E, Gomes J, Sales CC, Yousef S, Forouz F, Telaprolu KC, Roberts MS, Grice JE, Lopes PS, Leite-Silva VR, Andréo-Filho N. Deformable liposomes as enhancer of caffeine penetration through human skin in a Franz diffusion cell test. Int J Cosmet Sci 2020; 43:1-10. [PMID: 32866296 DOI: 10.1111/ics.12659] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/17/2020] [Accepted: 08/24/2020] [Indexed: 11/28/2022]
Abstract
OBJECTIVE The permeation of hydrophilic molecules through the skin is still a challenge due to the barrier posed by stratum corneum, the outermost layer of the skin. Liposomes have frequently been used as carriers for different types of drugs and may also function as permeation enhancers. Propylene glycol has also been used as an edge activator in liposomes to increase the permeation. The aim of this work was to prepare liposomes containing an edge activator and loaded with caffeine to evaluate the potential of caffeine reaching the deeper layers in the skin. METHODS The formulations were prepared by a top-down process using high-pressure homogenization at 200 00 psi for 10 min. They were characterized by size, polydispersity index (PI), zeta potential (ZP), pH, caffeine content and encapsulation efficiency (EE%) on preparation (time zero) and after 30 days. Cytotoxicity of blank and loaded liposomes was assessed by MTT proliferation assay with a normal keratinocyte cell line (HaCaT). In vitro permeation tests were performed with human skin in Franz cells over 24 h, and caffeine concentration was determined in the skin surface, stratum corneum, dermo-epidermal fraction and receptor medium by HPLC. RESULTS The caffeine liposomes with (DL-Caf) or without propylene glycol (CL-Caf) showed, respectively, mean size 94.5 and 95.4 nm, PI 0.48 and 0.42, ZP + 1.3 and + 18.1 mV and caffeine content of 78.57 and 80.13%. IC50 values of caffeine in DL-Caf (3.59 v/v %) and CL-Caf (3.65 v/v %) were not significantly different from conventional blank liposome (3.27 v/v %). The DL-Caf formulation presented the best capability to enhance the caffeine permeation through the skin, resulting 1.94-folds higher than caffeine solution. Furthermore, the caffeine flux from DL-Caf was 1.56- and 3.05-folds higher than caffeine solution and CL-Caf, respectively. On the other hand, CL-Caf showed the lowest caffeine penetration revealing the importance of edge activator to aid hydrophilic drug penetration to all skin layers. CONCLUSION The DL-Caf formulation tested was able to improve the permeation of caffeine through the stratum corneum and dermo-epidermal layers, suggesting that this delivery system may be effective for deep skin delivery of hydrophilic drugs.
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Affiliation(s)
- E Abd
- Therapeutics Research Centre, Translational Research Institute, Diamantina Institute, University of Queensland, 37 Kent Street, Woolloongabba, Qld., 4072, Australia
| | - J Gomes
- Departamento de Ciências Farmacêuticas, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Rua São Nicolau, 210, prédio de vidro, Diadema, SP, CEP 09913-030, Brazil
| | - C C Sales
- Departamento de Ciências Farmacêuticas, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Rua São Nicolau, 210, prédio de vidro, Diadema, SP, CEP 09913-030, Brazil
| | - S Yousef
- Therapeutics Research Centre, Translational Research Institute, Diamantina Institute, University of Queensland, 37 Kent Street, Woolloongabba, Qld., 4072, Australia.,Faculty of Pharmacy, Helwan University, Helwan, Cairo, 11795, Egypt
| | - F Forouz
- Therapeutics Research Centre, Translational Research Institute, Diamantina Institute, University of Queensland, 37 Kent Street, Woolloongabba, Qld., 4072, Australia
| | - K C Telaprolu
- Therapeutics Research Centre, Translational Research Institute, Diamantina Institute, University of Queensland, 37 Kent Street, Woolloongabba, Qld., 4072, Australia
| | - M S Roberts
- Therapeutics Research Centre, Translational Research Institute, Diamantina Institute, University of Queensland, 37 Kent Street, Woolloongabba, Qld., 4072, Australia.,Clinical and Health Sciences, City West Campus, Level 6 Cancer Research Institute (UniSA CRI), University of South Australia, North Terrace, Adelaide, S.A., 5000, Australia
| | - J E Grice
- Therapeutics Research Centre, Translational Research Institute, Diamantina Institute, University of Queensland, 37 Kent Street, Woolloongabba, Qld., 4072, Australia
| | - P S Lopes
- Departamento de Ciências Farmacêuticas, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Rua São Nicolau, 210, prédio de vidro, Diadema, SP, CEP 09913-030, Brazil
| | - V R Leite-Silva
- Therapeutics Research Centre, Translational Research Institute, Diamantina Institute, University of Queensland, 37 Kent Street, Woolloongabba, Qld., 4072, Australia.,Departamento de Ciências Farmacêuticas, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Rua São Nicolau, 210, prédio de vidro, Diadema, SP, CEP 09913-030, Brazil
| | - N Andréo-Filho
- Departamento de Ciências Farmacêuticas, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Rua São Nicolau, 210, prédio de vidro, Diadema, SP, CEP 09913-030, Brazil
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8
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Chapman FM, Sparham C, Hastie C, Sanders DJ, van Egmond R, Chapman KE, Doak SH, Scott AD, Jenkins GJS. Comparison of passive-dosed and solvent spiked exposures of pro-carcinogen, benzo[a]pyrene, to human lymphoblastoid cell line, MCL-5. Toxicol In Vitro 2020; 67:104905. [PMID: 32497684 DOI: 10.1016/j.tiv.2020.104905] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 02/26/2020] [Accepted: 05/28/2020] [Indexed: 11/17/2022]
Abstract
Genotoxicity testing methods in vitro provide a means to predict the DNA damaging effects of chemicals on human cells. This is hindered in the case of hydrophobic test compounds, however, which will partition to in vitro components such as plastic-ware and medium proteins, in preference to the aqueous phase of the exposure medium. This affects the freely available test chemical concentration, and as this freely dissolved aqueous concentration is that bioavailable to cells, it is important to define and maintain this exposure. Passive dosing promises to have an advantage over traditional 'solvent spiking' exposure methods and involves the establishment and maintenance of known chemical concentrations in the in vitro medium, and therefore aqueous phase. Passive dosing was applied in a novel format to expose the MCL-5 human lymphoblastoid cell line to the pro-carcinogen, benzo[a]pyrene (B[a]P) and was compared to solvent (dimethyl sulphoxide) spiked B[a]P exposures over 48 h. Passive dosing induced greater changes, at lower concentrations, to micronucleus frequency, p21 mRNA expression, cell cycle abnormalities, and cell and nuclear morphology. This was attributed to a maintained, definable, free chemical concentration using passive dosing and the presence or absence of solvent, and highlights the influence of exposure choice on genotoxic outcomes.
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Affiliation(s)
- Fiona M Chapman
- In Vitro Toxicology Group, Institute of Life Science 1, Swansea University Medical School, Singleton Campus, Swansea SA2 8PP, UK.
| | - Chris Sparham
- Safety and Environmental Assurance Centre, Unilever, Colworth House, Sharnbrook, Bedford MK44 1LQ, UK
| | - Colin Hastie
- Safety and Environmental Assurance Centre, Unilever, Colworth House, Sharnbrook, Bedford MK44 1LQ, UK
| | - David J Sanders
- Safety and Environmental Assurance Centre, Unilever, Colworth House, Sharnbrook, Bedford MK44 1LQ, UK
| | - Roger van Egmond
- Safety and Environmental Assurance Centre, Unilever, Colworth House, Sharnbrook, Bedford MK44 1LQ, UK
| | - Katherine E Chapman
- In Vitro Toxicology Group, Institute of Life Science 1, Swansea University Medical School, Singleton Campus, Swansea SA2 8PP, UK
| | - Shareen H Doak
- In Vitro Toxicology Group, Institute of Life Science 1, Swansea University Medical School, Singleton Campus, Swansea SA2 8PP, UK
| | - Andrew D Scott
- Safety and Environmental Assurance Centre, Unilever, Colworth House, Sharnbrook, Bedford MK44 1LQ, UK
| | - Gareth J S Jenkins
- In Vitro Toxicology Group, Institute of Life Science 1, Swansea University Medical School, Singleton Campus, Swansea SA2 8PP, UK
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9
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Reiter EB, Jahnke A, König M, Siebert U, Escher BI. Influence of Co-Dosed Lipids from Biota Extracts on the Availability of Chemicals in In Vitro Cell-Based Bioassays. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:4240-4247. [PMID: 32118404 PMCID: PMC7144218 DOI: 10.1021/acs.est.9b07850] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 02/27/2020] [Accepted: 03/01/2020] [Indexed: 05/21/2023]
Abstract
Extraction of chemicals from biota leads to co-extraction of lipids. When dosing such extracts into in vitro bioassays, co-dosed lipids act as an additional phase that can reduce the bioavailability of the chemicals and the apparent sensitivity of the assay. Equilibrium partitioning between medium, cells, and co-dosed lipids was described with an existing equilibrium partitioning model for cell-based bioassays extended by an additional lipid phase. We experimentally investigated the influence of co-dosed lipids on the effects elicited by four test chemicals of different hydrophobicity in two bioassays, indicative of the aryl hydrocarbon receptor and oxidative stress response (AREc32). The partitioning model explained the effect of the test chemicals in the presence of spiked triolein within a factor of 0.33-5.83 between the measured and predicted effect concentration (EC). We applied the model to marine mammal blubber extracted with silicone. Extracts dosed in the AREc32 bioassay showed a linear increase of apparent EC with increasing lipid fraction. The partitioning model was used to interpret the role of the co-extracted lipid. A quantitative lipid correction of bioassay results in the presence of co-dosed lipids was possible for known compounds and defined mixtures, while we could only estimate a range for mixtures of unknown chemicals.
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Affiliation(s)
- Eva B. Reiter
- Department
Cell Toxicology, Helmholtz Centre for Environmental
Research—UFZ, Permoserstraße 15, 04318 Leipzig, Germany
- E-mail: . Phone: +49 341 235 1823. Fax: +49 341 235 1787
| | - Annika Jahnke
- Department
Cell Toxicology, Helmholtz Centre for Environmental
Research—UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - Maria König
- Department
Cell Toxicology, Helmholtz Centre for Environmental
Research—UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - Ursula Siebert
- Institute
for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstr. 6, 25761 Büsum, Germany
| | - Beate I. Escher
- Department
Cell Toxicology, Helmholtz Centre for Environmental
Research—UFZ, Permoserstraße 15, 04318 Leipzig, Germany
- Environmental
Toxicology, Center for Applied Geoscience, Eberhard Karls University Tübingen, Hölderlinstr. 12, 72074 Tübingen, Germany
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10
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Fischer FC, Abele C, Henneberger L, Klüver N, König M, Mühlenbrink M, Schlichting R, Escher BI. Cellular Metabolism in High-Throughput In Vitro Reporter Gene Assays and Implications for the Quantitative In Vitro–In Vivo Extrapolation. Chem Res Toxicol 2020; 33:1770-1779. [DOI: 10.1021/acs.chemrestox.0c00037] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Fabian C. Fischer
- Department Cell Toxicology, Helmholtz Centre for Environmental Research—UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - Cedric Abele
- Department Cell Toxicology, Helmholtz Centre for Environmental Research—UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - Luise Henneberger
- Department Cell Toxicology, Helmholtz Centre for Environmental Research—UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - Nils Klüver
- Department Bioanalytical Ecotoxicology, Helmholtz Centre for Environmental Research—UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - Maria König
- Department Cell Toxicology, Helmholtz Centre for Environmental Research—UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - Marie Mühlenbrink
- Department Cell Toxicology, Helmholtz Centre for Environmental Research—UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - Rita Schlichting
- Department Cell Toxicology, Helmholtz Centre for Environmental Research—UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - Beate I. Escher
- Department Cell Toxicology, Helmholtz Centre for Environmental Research—UFZ, Permoserstraße 15, 04318 Leipzig, Germany
- Centre for Applied Geoscience, Eberhard Karls University Tübingen, 72074 Tübingen, Germany
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11
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Kristensen M, Christensen P, Christensen JH. Optimization and validation of a derivatization method with boron trifluoride in ethanol for analysis of aromatic carboxylic acids in water. J Chromatogr A 2019; 1601:21-26. [PMID: 31078279 DOI: 10.1016/j.chroma.2019.05.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/30/2019] [Accepted: 05/02/2019] [Indexed: 10/26/2022]
Abstract
Gas-chromatography (GC) analysis of carboxylic acids is limited by the high polarity and low volatility of most of these compounds. Boron trifluoride (BF3) mediated alkylation reactions is one of the most commonly used derivatization methods for making carboxylic acids GC compatible. A semi-automated BF3·EtOH (ethanol) derivatization method was optimized for comprehensive two-dimensional gas chromatography high-resolution mass spectrometry (GC × GC-HR MS) analysis of carboxylic acids in solid phase extraction (SPE) extracts of oil polluted water. The optimal derivatization method were found to be with addition of 300 μL BF3·EtOH per 200 μL sample and reaction at 75 °C for 24 h. Derivatives of eight selected acids (aliphatic, mono- and di-aromatic) were stable over 12 h with relative standard deviations (RSDs) of 2.0-10.7 %, the derivatization method was repeatable (RSDs of 3.2-17.2 %), detection limits (DL) and limit of detections (LODs) was in the range of DL = 0.53-1.63 ppb and LOD = 0.19-2.51 ppb for pure acid standards, and DL = 0.18-3.41 ppb and LOD = 0.28-5.46 ppb for matrix matched acid standards. Finally, the method was validated on the acidic fraction of a mixed anion-exchange SPE of oil polluted water. Thousands of degradation products from parent alkylated polycyclic aromatic hydrocarbons (PAHs) and aliphatic hydrocarbons, such as aliphatic acids and mono-, di- and tri- aromatic acids were analyzed by the applied method and compound groups were tentatively identified.
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Affiliation(s)
- Mette Kristensen
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark.
| | - Peter Christensen
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | - Jan H Christensen
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
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12
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Birch H, Kramer NI, Mayer P. Time-Resolved Freely Dissolved Concentrations of Semivolatile and Hydrophobic Test Chemicals in In Vitro Assays-Measuring High Losses and Crossover by Headspace Solid-Phase Microextraction. Chem Res Toxicol 2019; 32:1780-1790. [PMID: 31426631 DOI: 10.1021/acs.chemrestox.9b00133] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In vitro assays are normally conducted in plastic multiwell plates open to exchange with the ambient air. The concentration of test substances freely available to cells is often not known, can change over time, and is difficult to measure in the small volumes in microplates. However, even a well-characterized toxicological response is of limited value if it cannot be linked to a well-defined exposure level. The aim of this study was to develop and apply an approach for determining time-resolved freely dissolved concentrations of semivolatile and hydrophobic organic chemicals (SVHOCs) in in vitro assays: (1) free fractions were measured by a new medium dilution method and (2) time-resolved loss curves were obtained by measurements of total concentrations in 96-well plates during incubations at 37 °C. Headspace solid-phase microextraction was used as an analytical technique for 24 model chemicals spanning 6 chemical groups and 4-5 orders of magnitude in Kow and Kaw. Free fractions were >30% for chemicals with log Kow < 3.5 and then decreased with increasing log Kow. Medium concentrations declined significantly (>50%) within 24 h of incubation for all 20 chemicals having log Kow > 4 or log Kaw > -3.5 in serum-free medium. Losses of chemicals were lower for medium containing 10% fetal bovine serum, most significantly for chemicals with log Kow > 4. High crossover to neighboring wells also was observed below log Kow of 4 and log Kaw of -3.5. Sealing the well plates had limited effect on the losses but clearly reduced crossover. The high losses and crossover of most tested chemicals question the suitability of multiwell plates for in vitro testing of SVHOCs and call for (1) test systems that minimize losses, (2) methods to control in vitro exposure, (3) analytical confirmation of exposure, and (4) exposure control and confirmation being included in good in vitro reporting standards.
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Affiliation(s)
- Heidi Birch
- Department of Environmental Engineering , Technical University of Denmark , Bygningstorvet, Building 115 , 2800 Kongens Lyngby , Denmark
| | - Nynke I Kramer
- Institute for Risk Assessment Sciences , Utrecht University , 3508 TC Utrecht , The Netherlands
| | - Philipp Mayer
- Department of Environmental Engineering , Technical University of Denmark , Bygningstorvet, Building 115 , 2800 Kongens Lyngby , Denmark
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13
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Fischer FC, Henneberger L, Schlichting R, Escher BI. How To Improve the Dosing of Chemicals in High-Throughput in Vitro Mammalian Cell Assays. Chem Res Toxicol 2019; 32:1462-1468. [DOI: 10.1021/acs.chemrestox.9b00167] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Fabian C. Fischer
- Department Cell Toxicology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - Luise Henneberger
- Department Cell Toxicology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - Rita Schlichting
- Department Cell Toxicology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - Beate I. Escher
- Department Cell Toxicology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany
- Centre for Applied Geoscience, Eberhard Karls University Tübingen, 72074 Tübingen, Germany
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14
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Fischer M, Belanger SE, Berckmans P, Bernhard MJ, Bláha L, Coman Schmid DE, Dyer SD, Haupt T, Hermens JLM, Hultman MT, Laue H, Lillicrap A, Mlnaříková M, Natsch A, Novák J, Sinnige TL, Tollefsen KE, von Niederhäusern V, Witters H, Županič A, Schirmer K. Repeatability and Reproducibility of the RTgill-W1 Cell Line Assay for Predicting Fish Acute Toxicity. Toxicol Sci 2019; 169:353-364. [PMID: 30825313 PMCID: PMC6542334 DOI: 10.1093/toxsci/kfz057] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Predicting fish acute toxicity of chemicals in vitro is an attractive alternative method to the conventional approach using juvenile and adult fish. The rainbow trout (Oncorhynchus mykiss) cell line assay with RTgill-W1 cells has been designed for this purpose. It quantifies cell viability using fluorescent measurements for metabolic activity, cell- and lysosomal-membrane integrity on the same set of cells. Results from over 70 organic chemicals attest to the high predictive capacity of this test. We here report on the repeatability (intralaboratory variability) and reproducibility (interlaboratory variability) of the RTgill-W1 cell line assay in a round-robin study focusing on 6 test chemicals involving 6 laboratories from the industrial and academic sector. All participating laboratories were able to establish the assay according to preset quality criteria even though, apart from the lead laboratory, none had previously worked with the RTgill-W1 cell line. Concentration-response modeling, based on either nominal or geometric mean-derived measured concentrations, yielded effect concentrations (EC50) that spanned approximately 4 orders of magnitude over the chemical range, covering all fish acute toxicity categories. Coefficients of variation for intralaboratory and interlaboratory variability for the average of the 3 fluorescent cell viability measurements were 15.5% and 30.8%, respectively, which is comparable to other fish-derived, small-scale bioassays. This study therefore underlines the robustness of the RTgill-W1 cell line assay and its accurate performance when carried out by operators in different laboratory settings.
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Affiliation(s)
- Melanie Fischer
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, 8600 Dübendorf, Switzerland
| | - Scott E Belanger
- The Procter & Gamble Company, Global Product Stewardship, Mason, Ohio 45040, USA
| | - Pascale Berckmans
- VITO-ABS team, Department of Environmental Risk and Health, Flemish Institute for Technological Research, 2400 Mol, Belgium
| | - Mary J Bernhard
- The Procter & Gamble Company, Global Product Stewardship, Mason, Ohio 45040, USA
| | - Ludek Bláha
- RECETOX, Faculty of Science, Masaryk University, 625 00 Brno-Bohunice, Czech Republic
| | - Diana E Coman Schmid
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, 8600 Dübendorf, Switzerland
- ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics, 8093 Zürich, Switzerland
| | - Scott D Dyer
- The Procter & Gamble Company, Global Product Stewardship, Mason, Ohio 45040, USA
| | - Tina Haupt
- Givaudan Schweiz AG, Department of In vitro Molecular Screening, 8310 Kemptthal, Switzerland
| | - Joop L M Hermens
- IRAS, The Institute for Risk Assessment Sciences, Toxicology Division, Utrecht University, 3584 CL Utrecht, The Netherlands
| | - Maria T Hultman
- Norwegian Institute for Water Research (NIVA), Section for ecotoxicology, 0349 Oslo, Norway
| | - Heike Laue
- Givaudan Schweiz AG, Department of In vitro Molecular Screening, 8310 Kemptthal, Switzerland
| | - Adam Lillicrap
- Norwegian Institute for Water Research (NIVA), Section for ecotoxicology, 0349 Oslo, Norway
| | - Marie Mlnaříková
- RECETOX, Faculty of Science, Masaryk University, 625 00 Brno-Bohunice, Czech Republic
| | - Andreas Natsch
- Givaudan Schweiz AG, Department of In vitro Molecular Screening, 8310 Kemptthal, Switzerland
| | - Jiří Novák
- RECETOX, Faculty of Science, Masaryk University, 625 00 Brno-Bohunice, Czech Republic
| | - Theo L Sinnige
- IRAS, The Institute for Risk Assessment Sciences, Toxicology Division, Utrecht University, 3584 CL Utrecht, The Netherlands
| | - Knut Erik Tollefsen
- Norwegian Institute for Water Research (NIVA), Section for ecotoxicology, 0349 Oslo, Norway
| | | | - Hilda Witters
- VITO-ABS team, Department of Environmental Risk and Health, Flemish Institute for Technological Research, 2400 Mol, Belgium
| | - Anze Županič
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, 8600 Dübendorf, Switzerland
- ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics, 8093 Zürich, Switzerland
| | - Kristin Schirmer
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, 8600 Dübendorf, Switzerland
- ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics, 8093 Zürich, Switzerland
- EPF Lausanne, School of Architecture, Civil and Environmental Engineering, 1015 Lausanne, Switzerland
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15
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Phototoxic risk assessment on benzophenone UV filters: In vitro assessment and a theoretical model. Toxicol In Vitro 2019; 60:180-186. [PMID: 31154060 DOI: 10.1016/j.tiv.2019.05.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 05/27/2019] [Accepted: 05/29/2019] [Indexed: 02/05/2023]
Abstract
Benzophenones (BPs), filtering out both UVA and UVB rays, are widely used in a great variety of sunscreens and personal care products. However, they have not been extensively studied for the mechanisms of UV-absorbing toxicity. In this study, we used CPZ (chlorpromazine) as a positive control and SDS (sodium dodecyl sulfate) as a negative control, and the phototoxic of BP-1, BP-3 and BP-4 were investigated in vitro assays using three cell types under different UV exposure conditions. This was followed by setting up a theoretical model, which was adopted to predict and compare the phototoxicity. It was found that Balb/c 3T3 (Balb/c 3T3 fibroblast cell lines) showed sensitivity to UVA+ and UVB+ exposure, while the HS68 (human HS68 fibroblast cell lines) to UVA+ and the HaCaT (human HaCaT keratinocyte cell lines) to UVB+. The test compound, BP-1, was detected to be phototoxic at UVA+ conditions, but BP-3 and BP-4 were discovered to be non-phototoxic at UVA+ conditions. This demonstrated that BP-1, BP-3 and BP-4 remained low-risk chemicals under UVB+ condition. The theoretical calculation of the energy gap (EGAP) showed BP-1(EGAP) > BP-3(EGAP) > BP-4(EGAP).
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16
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Groothuis FA, Timmer N, Opsahl E, Nicol B, Droge STJ, Blaauboer BJ, Kramer NI. Influence of in Vitro Assay Setup on the Apparent Cytotoxic Potency of Benzalkonium Chlorides. Chem Res Toxicol 2019; 32:1103-1114. [PMID: 31012305 PMCID: PMC6584903 DOI: 10.1021/acs.chemrestox.8b00412] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The nominal concentration
is generally used to express concentration–effect
relationships in in vitro toxicity assays. However, the nominal concentration
does not necessarily represent the exposure concentration responsible
for the observed effect. Surfactants accumulate at interphases and
likely sorb to in vitro system components such as serum protein and
well plate plastic. The extent of sorption and the consequences of
this sorption on in vitro readouts is largely unknown for these chemicals.
The aim of this study was to demonstrate the effect of sorption to
in vitro components on the observed cytotoxic potency of benzalkonium
chlorides (BAC) varying in alkyl chain length (6–18 carbon
atoms, C6–18) in a basal cytotoxicity assay with
the rainbow trout gill cell line (RTgill-W1). Cells were exposed for
48 h in 96-well plates to increasing concentration of BACs in exposure
medium containing 0, 60 μM bovine serum albumin (BSA) or 10%
fetal bovine serum (FBS). Before and after exposure, BAC concentrations
in exposure medium were analytically determined. Based on freely dissolved
concentrations at the end of the exposure, median effect concentrations
(EC50) decreased with increasing alkyl chain length up
to 14 carbons. For BAC with alkyl chains of 12 or more carbons, EC50’s based on measured concentrations after exposure
in supplement-free medium were up to 25-times lower than EC50’s calculated using nominal concentrations. When BSA or FBS
was added to the medium, a decrease in cytotoxic potency of up to
22 times was observed for BAC with alkyl chains of eight or more carbons.
The results of this study emphasize the importance of expressing the
in vitro readouts as a function of a dose metric that is least influenced
by assay setup to compare assay sensitivities and chemical potencies.
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Affiliation(s)
- Floris A Groothuis
- Institute for Risk Assessment Sciences , Utrecht University , PO Box 80177, 3508 TD Utrecht , The Netherlands
| | - Niels Timmer
- Institute for Risk Assessment Sciences , Utrecht University , PO Box 80177, 3508 TD Utrecht , The Netherlands
| | - Eystein Opsahl
- Institute for Risk Assessment Sciences , Utrecht University , PO Box 80177, 3508 TD Utrecht , The Netherlands
| | - Beate Nicol
- Safety & Environmental Assurance Centre , Unilever U.K. , Colworth Science Park, Sharnbrook, Bedford MK44 1LQ , United Kingdom
| | - Steven T J Droge
- Institute for Risk Assessment Sciences , Utrecht University , PO Box 80177, 3508 TD Utrecht , The Netherlands
| | - Bas J Blaauboer
- Institute for Risk Assessment Sciences , Utrecht University , PO Box 80177, 3508 TD Utrecht , The Netherlands
| | - Nynke I Kramer
- Institute for Risk Assessment Sciences , Utrecht University , PO Box 80177, 3508 TD Utrecht , The Netherlands
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17
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Lammel T, Tsoukatou G, Jellinek J, Sturve J. Development of three-dimensional (3D) spheroid cultures of the continuous rainbow trout liver cell line RTL-W1. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 167:250-258. [PMID: 30342358 DOI: 10.1016/j.ecoenv.2018.10.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 09/29/2018] [Accepted: 10/02/2018] [Indexed: 06/08/2023]
Abstract
In vitro experimental systems based on continuous piscine cell lines can be used as an alternative to animal tests for obtaining qualitative and quantitative information on the possible fate and effect of chemicals in fish. However, their capability to reproduce complex metabolic processes and toxic responses as they occur in vivo is limited due to the lack of organ-specific tissue architecture and functions. Here we introduce a three-dimensional (3D) in vitro experimental system based on spheroidal aggregate cultures (spheroids) of the continuous rainbow trout liver cell line RTL-W1 and provide a first description of their structural and functional properties including growth, viability/longevity, metabolic activity, ultrastructure and cytochrome P450 1A (CYP1A) expression determined by bright-field, multi-photon fluorescence and transmission electron microscopy as well as RT-qPCR analysis. Our results show that RTL-W1 cells in 3D spheroids (ø ~ 150 µm) (including those in the interior) were viable, metabolically active and had higher basal and β-naphthoflavone-induced CYP1A expression levels than conventional 2D cell cultures. Furthermore, they displayed ultrastructural characteristics similar to differentiated hepatocytes. The available evidence suggests that 3D RTL-W1 spheroids may have enhanced hepatotypic functions and be a superior in vitro model to assess hepatic biotransformation, bioaccumulation and chronic toxicity compared to conventional cell monolayer cultures.
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Affiliation(s)
- Tobias Lammel
- Department of Biological and Environmental Sciences, University of Gothenburg, Medicinaregatan 18 A, Box 463, 413 90 Göteborg, Sweden.
| | - Georgia Tsoukatou
- Department of Biological and Environmental Sciences, University of Gothenburg, Medicinaregatan 18 A, Box 463, 413 90 Göteborg, Sweden
| | - Johanna Jellinek
- Department of Biological and Environmental Sciences, University of Gothenburg, Medicinaregatan 18 A, Box 463, 413 90 Göteborg, Sweden
| | - Joachim Sturve
- Department of Biological and Environmental Sciences, University of Gothenburg, Medicinaregatan 18 A, Box 463, 413 90 Göteborg, Sweden
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18
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Maner J, Burkard M, Cassano JC, Nash SMB, Schirmer K, Suter MJF. Hexachlorobenzene exerts genotoxic effects in a humpback whale cell line under stable exposure conditions. RSC Adv 2019; 9:39447-39457. [PMID: 35540658 PMCID: PMC9076109 DOI: 10.1039/c9ra05352b] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 11/15/2019] [Indexed: 01/04/2023] Open
Abstract
Humpback whales, like other polar wildlife, accumulate persistent organic pollutants. In Southern hemisphere populations, hexachlorobenzene (HCB) dominates the contaminant profiles. HCB is linked to a variety of health effects and is classified as a group 2B carcinogen, but the mechanism of action is a matter of contention. Potential toxicological effects to humpback whales remain entirely unknown. The recently established humpback whale fibroblast cell line (HuWa) offers an in vitro model for toxicological investigations. We here combine this novel cell line with a passive dosing strategy to investigate whale-specific toxicity of HCB. The relevant partitioning coefficients were determined to produce stable and predictable exposure concentrations in small-scale bioassays. The system was used to assess acute toxicity as well as genotoxicity of HCB to the HuWa cell line. While we found some transient reductions in metabolic activity, measured with the indicator dye alamarBlue, no clear acute toxic effects were discernible. Yet, a significant increase in DNA damage, detected in the alkaline comet assay, was found in HuWa cells exposed to 10 μg L−1 HCB during the sensitive phase of cell attachment. Collectively, this work provides a ready-to-use passive dosing system and delivers evidence that HCB elicits genotoxicity in humpback whale cells. Stable exposure concentrations for hexachlorobenzene (HCB) can be achieved using silicone O-rings for passive dosing. Using this setup it was found that HCB causes DNA damage in a cell line of humpback whale fibroblasts.![]()
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Affiliation(s)
- Jenny Maner
- Department Environmental Toxicology
- Eawag, Swiss Federal Institute of Aquatic Science and Technology
- Switzerland
- Department of Environmental Systems Science
- ETH Zürich
| | - Michael Burkard
- Department Environmental Toxicology
- Eawag, Swiss Federal Institute of Aquatic Science and Technology
- Switzerland
- Southern Ocean Persistent Organic Pollutants Program
- Environmental Futures Research Institute
| | - Juan Carlos Cassano
- Empa, Swiss Laboratories for Material Science and Technology
- Particle-Biology Interactions Laboratory
- Switzerland
| | - Susan M. Bengtson Nash
- Southern Ocean Persistent Organic Pollutants Program
- Environmental Futures Research Institute
- Griffith University
- Brisbane
- Australia
| | - Kristin Schirmer
- Department Environmental Toxicology
- Eawag, Swiss Federal Institute of Aquatic Science and Technology
- Switzerland
- Department of Environmental Systems Science
- ETH Zürich
| | - Marc J.-F. Suter
- Department Environmental Toxicology
- Eawag, Swiss Federal Institute of Aquatic Science and Technology
- Switzerland
- Department of Environmental Systems Science
- ETH Zürich
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19
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Gol D, Thakkar S, Misra M. Nanocrystal-based drug delivery system of risperidone: lyophilization and characterization. Drug Dev Ind Pharm 2018; 44:1458-1466. [PMID: 29619857 DOI: 10.1080/03639045.2018.1460377] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
OBJECTIVE In the present work nanocrystal-based formulation of risperidone (RIS) was proposed to overcome solubility issue of RIS, while lyophilization technique was used effectively, for conversion of RIS nanosuspension to solid state. SIGNIFICANCE RIS nanosuspension was developed and stabilized with a combination of polycaprolactone and Pluronic® F-68 as stabilizers. With focus on critical parameters like nature of cryoprotectants and effect of eutectic temperature on properties of nanosuspension, the suitability of lyophilization technique in improving the physical stability of prepared nanosuspension was also evaluated. Additionally, the developed nanocrystals were also assessed for their solid states properties. METHODS Various process parameters affecting average particle size and polydispersity index (PDI), viz. drug to surfactant ratio, solvent to anti-solvent ratio, stirring speed, type of stabilizer were optimized. Assessment of lyophilization as a suitable solidification technique (for conversion to powder form) was done with selective cryoprotectants (trehalose dihydrate and sorbitol). RESULTS The formulation was found to be stable at 4 °C for 3 months with size, PDI and zeta potential of 214 ± 3.4 nm, 0.120, and -10.2 ± 0.90 mV, respectively. Release profile of developed nanosuspension showed cumulative % release of ∼90% in initial 10 h whereas the value for the unprocessed drug was ∼11% in same time frame. CONCLUSIONS These findings suggest that developed formulation was able to enhance water solubility of the drug effectively and can be potentially used in the management of psychotic disorders.
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Affiliation(s)
- Dharmesh Gol
- a National Institute of Pharmaceutical Education and Research (NIPER) , Ahmedabad , India
| | - Shreya Thakkar
- a National Institute of Pharmaceutical Education and Research (NIPER) , Ahmedabad , India
| | - Manju Misra
- a National Institute of Pharmaceutical Education and Research (NIPER) , Ahmedabad , India
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20
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Välitalo P, Massei R, Heiskanen I, Behnisch P, Brack W, Tindall AJ, Du Pasquier D, Küster E, Mikola A, Schulze T, Sillanpää M. Effect-based assessment of toxicity removal during wastewater treatment. WATER RESEARCH 2017; 126:153-163. [PMID: 28941401 DOI: 10.1016/j.watres.2017.09.014] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 08/24/2017] [Accepted: 09/04/2017] [Indexed: 06/07/2023]
Abstract
Wastewaters contain complex mixtures of chemicals, which can cause adverse toxic effects in the receiving environment. In the present study, the toxicity removal during wastewater treatment at seven municipal wastewater treatment plants (WWTPs) was investigated using an effect-based approach. A battery of eight bioassays was applied comprising of cytotoxicity, genotoxicity, endocrine disruption and fish embryo toxicity assays. Human cell-based CALUX assays, transgenic larval models and the fish embryo toxicity test were particularly sensitive to WWTP effluents. The results indicate that most effects were significantly reduced or completely removed during wastewater treatment (76-100%), while embryo toxicity, estrogenic activity and thyroid disruption were still detectable in the effluents suggesting that some harmful substances remain after treatment. The responsiveness of the bioassays was compared and the human cell-based CALUX assays showed highest responsiveness in the samples. Additionally, the fish embryo toxicity test and the transgenic larval models for endocrine disrupting effects showed high responsiveness at low sample concentrations in nearly all of the effluent samples. The results showed a similar effect pattern among all WWTPs investigated, indicating that the wastewater composition could be rather similar at different locations. There were no considerable differences in the toxicity removal efficiencies of the treatment plants and no correlation was observed with WWTP characteristics, such as process configuration or sludge age. This study demonstrated that a biotest battery comprising of multiple endpoints can serve as a powerful tool when assessing water quality or water treatment efficiency in a holistic manner. Rather than analyzing the concentrations of a few selected chemicals, bioassays can be used to complement traditional methods of monitoring in the future by assessing sum-parameter based effects, such as mixture effects, and tackling chemicals that are present at concentrations below chemical analytical detection limits.
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Affiliation(s)
- Pia Välitalo
- Finnish Environment Institute, Laboratory Centre, Hakuninmaantie 6, 00430, Helsinki, Finland; Aalto University, Department of Civil and Environmental Engineering, Tietotie 1E, 02150, Espoo, Finland.
| | - Riccardo Massei
- UFZ - Helmholtz Centre for Environmental Research GmbH, Leipzig, Germany; Institute for Environmental Research (Biology V), RWTH Aachen University, Aachen, Germany
| | - Ilse Heiskanen
- Finnish Environment Institute, Laboratory Centre, Hakuninmaantie 6, 00430, Helsinki, Finland
| | | | - Werner Brack
- UFZ - Helmholtz Centre for Environmental Research GmbH, Leipzig, Germany; Institute for Environmental Research (Biology V), RWTH Aachen University, Aachen, Germany
| | | | | | - Eberhard Küster
- UFZ - Helmholtz Centre for Environmental Research GmbH, Leipzig, Germany
| | - Anna Mikola
- Aalto University, Department of Civil and Environmental Engineering, Tietotie 1E, 02150, Espoo, Finland
| | - Tobias Schulze
- UFZ - Helmholtz Centre for Environmental Research GmbH, Leipzig, Germany
| | - Markus Sillanpää
- Finnish Environment Institute, Laboratory Centre, Hakuninmaantie 6, 00430, Helsinki, Finland
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21
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Drieschner C, Minghetti M, Wu S, Renaud P, Schirmer K. Ultrathin Alumina Membranes as Scaffold for Epithelial Cell Culture from the Intestine of Rainbow Trout. ACS APPLIED MATERIALS & INTERFACES 2017; 9:9496-9505. [PMID: 28244327 DOI: 10.1021/acsami.7b00705] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Permeable membranes are indispensable for in vitro epithelial barrier models. However, currently available polymer-based membranes are low in porosity and relatively thick, resulting in a limited permeability and unrealistic culture conditions. In this study, we developed an ultrathin, nanoporous alumina membrane as novel cell culture interface for vertebrate cells, with focus on the rainbow trout (Onchorynchus mykiss) intestinal cell line RTgutGC. The new type of membrane is framed in a silicon chip for physical support and has a thickness of only 1 μm, with a porosity of 15% and homogeneous nanopores (Ø = 73 ± 21 nm). Permeability rates for small molecules, namely lucifer yellow, dextran 40, and bovine serum albumin, exceeded those of standard polyethylene terephthalate (PET) membranes by up to 27 fold. With the final goal to establish a representative model of the fish intestine for environmental toxicology, we engineered a simple culture setup, capable of testing the cellular response toward chemical exposure. Herein, cells were cultured in a monolayer on the alumina membranes and formed a polarized epithelium with apical expression of the tight junction protein ZO-1 within 14 days. Impedance spectroscopy, a noninvasive and real time electrical measurement, was used to determine cellular resistance during epithelial layer formation and chemical exposure to evaluate barrier functionality. Resistance values during epithelial development revealed different stages of epithelial maturity and were comparable with the in vivo situation. During chemical exposure, cellular resistance changed immediately when barrier tightness or cell viability was affected. Thus, our study demonstrates nanoporous alumina membranes as promising novel interface for alternative in vitro approaches, capable of allowing cell culture in a physiologically realistic manner and enabling high quality microscopy and sensitive measurement of cellular resistance.
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Affiliation(s)
- Carolin Drieschner
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , 8600 Dübendorf, Switzerland
- Microsystems Laboratory 4, School of Architecture, École Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
| | - Matteo Minghetti
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , 8600 Dübendorf, Switzerland
- Department of Integrative Biology, Oklahoma State University , 74078 Oklahoma, United States
| | - Songmei Wu
- Microsystems Laboratory 4, School of Architecture, École Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
- School of Science, Beijing Jiaotong University , 100044 Beijing, P. R China
| | - Philippe Renaud
- Microsystems Laboratory 4, School of Architecture, École Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
| | - Kristin Schirmer
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , 8600 Dübendorf, Switzerland
- Department of Civil and Environmental Engineering, School of Architecture, École Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics, ETH-Zürich , 8093 Zürich, Switzerland
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Kwon JH, Lee SY, Kang HJ, Mayer P, Escher BI. Including Bioconcentration Kinetics for the Prioritization and Interpretation of Regulatory Aquatic Toxicity Tests of Highly Hydrophobic Chemicals. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:12004-12011. [PMID: 27715022 DOI: 10.1021/acs.est.6b03942] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Worldwide, regulations of chemicals require short-term toxicity data for evaluating hazards and risks of the chemicals. Current data requirements on the registration of chemicals are primarily based on tonnage and do not yet consider properties of chemicals. For example, short-term ecotoxicity data are required for chemicals with production volume greater than 1 or 10 ton/y according to REACH, without considering chemical properties. Highly hydrophobic chemicals are characterized by low water solubility and slow bioconcentration kinetics, which may hamper the interpretation of short-term toxicity experiments. In this work, internal concentrations of highly hydrophobic chemicals were predicted for standard acute ecotoxicity tests at three trophic levels, algae, invertebrate, and fish. As demonstrated by comparison with maximum aqueous concentrations at water solubility, chemicals with an octanol-water partition coefficient (Kow) greater than 106 are not expected to reach sufficiently high internal concentrations for exerting effects within the test duration of acute tests with fish and invertebrates, even though they might be intrinsically toxic. This toxicity cutoff was explained by the slow uptake, i.e., by kinetics, not by thermodynamic limitations. Predictions were confirmed by data entries of the OECD's screening information data set (SIDS) (n = 746), apart from a few exceptions concerning mainly organometallic substances and those with inconsistency between water solubility and Kow. Taking error propagation and model assumptions into account, we thus propose a revision of data requirements for highly hydrophobic chemicals with log Kow > 7.4: Short-term toxicity tests can be limited to algae that generally have the highest uptake rate constants, whereas the primary focus of the assessment should be on persistence, bioaccumulation, and long-term effects.
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Affiliation(s)
- Jung-Hwan Kwon
- Division of Environmental Science and Ecological Engineering, Korea University , 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - So-Young Lee
- Division of Environmental Science and Ecological Engineering, Korea University , 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Hyun-Joong Kang
- Division of Environmental Science and Ecological Engineering, Korea University , 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Philipp Mayer
- Department of Environmental Engineering, Technical University of Denmark , Bygningstorvet B115, DK-2800 Kongens Lyngby, Denmark
| | - Beate I Escher
- Department of Cell Toxicology, Helmholtz Centre for Environmental Research - UFZ , Permoserstrasse 15, DE-04318 Leipzig, Germany
- Environmental Toxicology, Center for Applied Geoscience, Eberhard Karls University Tübingen , Hölderlinstrasse 12, DE-72074 Tübingen, Germany
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Carmona-Antoñanzas G, Humble JL, Carmichael SN, Heumann J, Christie HR, Green DM, Bassett DI, Bron JE, Sturm A. Time-to-response toxicity analysis as a method for drug susceptibility assessment in salmon lice. AQUACULTURE (AMSTERDAM, NETHERLANDS) 2016; 464:570-575. [PMID: 27812230 PMCID: PMC5035062 DOI: 10.1016/j.aquaculture.2016.08.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 08/01/2016] [Accepted: 08/03/2016] [Indexed: 06/06/2023]
Abstract
UNLABELLED The salmon louse Lepeophtheirus salmonis (Krøyer, 1837) is an ectoparasite causing infections of wild and farmed Atlantic salmon (Salmo salar L.) in the Northern hemisphere. While L. salmonis control at commercial mariculture sites increasingly employs non-medicinal approaches, such as cage designs reducing infection rates and biological control through cleaner fish, anti-parasitic drugs are still a requirement for effective fish health care. With only a limited range of salmon delousing agents available, all of which have been in use for more than a decade, drug resistance formation has been reported for different products. Successful resistance management requires reliable susceptibility assessment, which is usually achieved through L. salmonis bioassays. These tests involve the exposure of parasites to different drug concentrations and require significant numbers of suitable L. salmonis stages. The present study reports an alternative bioassay that is based on time-to-response toxicity analyses and can be carried out with limited parasite numbers. The assay determines the median effective time (ET50), i.e., the time required until impaired swimming and/or attachment behaviour becomes apparent in 50% of parasites, by conducting repeated examinations of test animals starting at the time point where exposure to a set drug concentration commences. This experimental approach further allows the estimation of the apparent drug susceptibility of individual L. salmonis by determining their time to response, which may prove useful in experiments designed to elucidate associations between genetic factors and the drug susceptibility phenotype of parasites. Three laboratory strains of L. salmonis differing in susceptibility to emamectin benzoate were characterised using standard 24 h bioassays and time-to-response toxicity assays. While both the median effective concentration (EC50) and the ET50 showed variability between experimental repeats, both types of bioassay consistently discriminated susceptible and drug-resistant L. salmonis laboratory strains. STATEMENT OF RELEVANCE Infections by sea lice cause significant costs to the global salmon farming industry, which have been estimated to exceed €300 million per year worldwide. Control of sea lice still relies to a significant extent on chemical delousing; however, chemical control is threatened by resistance formation. Resistance can be combated by rotation between different drugs and strategic implementation of non-medicinal strategies. However, resistance management requires reliable and feasible methods of susceptibility assessment. The present study is a technical note introducing a novel approach to susceptibility assessments in sea lice. The method can be applied in susceptibility assessments on farms, where it offers the advantage of a reduced requirement of parasites for testing. In addition, the novel method allows deriving the times of parasite require to show a response after drug treatment has started, thus providing a variable characterizing the drug susceptibility phenotype of individual parasites. Accordingly, the bioassay approach presented here will be useful for studies aiming at unravelling the genetic determinants of drug resistance.
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Affiliation(s)
- Greta Carmona-Antoñanzas
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, Scotland, UK
| | - Joseph L. Humble
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, Scotland, UK
| | - Stephen N. Carmichael
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, Scotland, UK
| | - Jan Heumann
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, Scotland, UK
| | - Hayden R.L. Christie
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, Scotland, UK
| | - Darren M. Green
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, Scotland, UK
| | - David I. Bassett
- Marine Environmental Research Laboratory, University of Stirling, Machrihanish, Argyll, PA28 6PZ, Scotland, UK
| | - James E. Bron
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, Scotland, UK
| | - Armin Sturm
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, Scotland, UK
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Paterson S, Thompson SA, Gracie J, Wark AW, de la Rica R. Self-assembly of gold supraparticles with crystallographically aligned and strongly coupled nanoparticle building blocks for SERS and photothermal therapy. Chem Sci 2016; 7:6232-6237. [PMID: 30034763 PMCID: PMC6024203 DOI: 10.1039/c6sc02465c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 06/20/2016] [Indexed: 12/13/2022] Open
Abstract
A new method is introduced for self-assembling citrate-capped gold nanoparticles into supraparticles with crystallographically aligned building blocks. It consists in confining gld nanoparticles inside a cellulose acetate membrane. The constituent nanoparticles are in close contact in the superstructure, and therefore generate hot spots leading to intense Surface-Enhanced Raman Scattering (SERS) signals. They also generate more plasmonic heat than the nanoparticle building blocks. The supraparticles are internalized by cells and show low cytotoxicity, but can kill cancer cells when irradiated with a laser. This, along with the improved plasmonic properties arising from their assembly, makes the gold supraparticles promising materials for applications in bioimaging and nanomedicine.
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Affiliation(s)
- S Paterson
- Department of Pure and Applied Chemistry , WestCHEM , University of Strathclyde , Technology and Innovation Centre , 99 George Street , Glasgow , G1 1RD , Scotland , UK .
| | - S A Thompson
- Department of Pure and Applied Chemistry , WestCHEM , University of Strathclyde , Technology and Innovation Centre , 99 George Street , Glasgow , G1 1RD , Scotland , UK .
- Department of Chemistry and Biochemistry , Hunter College-City University of New York , New York 10065 , USA
| | - J Gracie
- Department of Pure and Applied Chemistry , WestCHEM , University of Strathclyde , Technology and Innovation Centre , 99 George Street , Glasgow , G1 1RD , Scotland , UK .
| | - A W Wark
- Department of Pure and Applied Chemistry , WestCHEM , University of Strathclyde , Technology and Innovation Centre , 99 George Street , Glasgow , G1 1RD , Scotland , UK .
| | - R de la Rica
- Department of Pure and Applied Chemistry , WestCHEM , University of Strathclyde , Technology and Innovation Centre , 99 George Street , Glasgow , G1 1RD , Scotland , UK .
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Defining and Controlling Exposure During In Vitro Toxicity Testing and the Potential of Passive Dosing. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2016; 157:263-292. [DOI: 10.1007/10_2015_5017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Smith KEC, Jeong Y, Kim J. Passive dosing versus solvent spiking for controlling and maintaining hydrophobic organic compound exposure in the Microtox® assay. CHEMOSPHERE 2015; 139:174-180. [PMID: 26117202 DOI: 10.1016/j.chemosphere.2015.06.028] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 05/12/2015] [Accepted: 06/10/2015] [Indexed: 06/04/2023]
Abstract
Microbial toxicity bioassays such as the Microtox® test are ubiquitously applied to measure the toxicity of chemicals and environmental samples. In many ways their operation is conducive to the testing of organic chemicals. They are of short duration, use glass cuvettes and take place at reduced temperatures in medium lacking sorbing components. All of these are expected to reduce sorptive and volatile losses, but particularly for hydrophobic organics the role of such losses in determining the bioassay response remains unclear. This study determined the response of the Microtox® test when using solvent spiking compared to passive dosing for introducing the model hydrophobic compounds acenaphthene, phenanthrene, fluoranthene and benzo(a)pyrene. Compared to solvent spiking, the apparent sensitivity of the Microtox® test with passive dosing was 3.4 and 12.4 times higher for acenaphthene and phenanthrene, respectively. Furthermore, fluoranthene only gave a consistent response with passive dosing. Benzo(a)pyrene did not result in a response with either spiking or passive dosing even at aqueous solubility. Such differences in the apparent sensitivity of the Microtox® test can be traced back to the precise definition of the dissolved exposure concentrations and the buffering of losses with passive dosing. This highlights the importance of exposure control even in simple and short-term microbial bioassays such as the Microtox® test.
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Affiliation(s)
- Kilian E C Smith
- Korea Institute of Science and Technology, Campus E 7.1, Universität des Saarlandes, Saarbrücken, Germany.
| | - Yoonah Jeong
- Korea Institute of Science and Technology, Campus E 7.1, Universität des Saarlandes, Saarbrücken, Germany
| | - Jongwoon Kim
- Korea Institute of Science and Technology, Campus E 7.1, Universität des Saarlandes, Saarbrücken, Germany
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Gilbert D, Mayer P, Pedersen M, Vinggaard AM. Endocrine activity of persistent organic pollutants accumulated in human silicone implants--Dosing in vitro assays by partitioning from silicone. ENVIRONMENT INTERNATIONAL 2015; 84:107-114. [PMID: 26264162 DOI: 10.1016/j.envint.2015.07.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 05/28/2015] [Accepted: 07/04/2015] [Indexed: 06/04/2023]
Abstract
Persistent organic pollutants (POPs) accumulated in human tissues may pose a risk for human health by interfering with the endocrine system. This study establishes a new link between actual human internal POP levels and the endocrine active dose in vitro, applying partitioning-controlled dosing from silicone to the H295R steroidogenesis assay: (1) Measured concentrations of POPs in silicone breast implants were taken from a recent study and silicone disks were loaded according to these measurements. (2) Silicone disks were transferred into H295R cell culture plates in order to control exposure of the adrenal cells by equilibrium partitioning. (3) Hormone production of the adrenal cells was measured as toxicity endpoint. 4-Nonylphenol was used for method development, and the new dosing method was compared to conventional solvent-dosing. The two dosing modes yielded similar dose-dependent hormonal responses of H295R cells. However, with the partitioning-controlled freely dissolved concentrations (Cfree) as dose metrics, dose-response curves were left-shifted by two orders of magnitude relative to spiked concentrations. Partitioning-controlled dosing of POPs resulted in up to 2-fold increases in progestagen and corticosteroid levels at Cfree of individual POPs in or below the femtomolar range. Silicone acted not only as source of the POPs but also as a sorption sink for lipophilic hormones, stimulating the cellular hormone production. Methodologically, the study showed that silicone can be used as reference partitioning phase to transfer in vivo exposure in humans (silicone implants) to in vitro assays (partition-controlled dosing). The main finding was that POPs at the levels at which they are found in humans can interfere with steroidogenesis in a human adrenocortical cell line.
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Affiliation(s)
- Dorothea Gilbert
- Division of Diet, Disease Prevention and Toxicology, National Food Institute, Technical University of Denmark, Mørkhøj Bygade 19, DK-2860 Søborg, Denmark; Department of Environmental Science, Aarhus University, Frederiksborgvej 399, DK-4000 Roskilde, Denmark
| | - Philipp Mayer
- Department of Environmental Engineering, DTU Environment, Technical University of Denmark, Miljøvej 113, DK-2800 Kgs. Lyngby, Denmark
| | - Mikael Pedersen
- Division of Food Chemistry, National Food Institute, Technical University of Denmark, Mørkhøj Bygade 19, DK-2860 Søborg, Denmark
| | - Anne Marie Vinggaard
- Division of Diet, Disease Prevention and Toxicology, National Food Institute, Technical University of Denmark, Mørkhøj Bygade 19, DK-2860 Søborg, Denmark.
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Justo OR, Simioni PU, Gabriel DL, Tamashiro WMDSC, Rosa PDTV, Moraes ÂM. Evaluation of in vitro anti-inflammatory effects of crude ginger and rosemary extracts obtained through supercritical CO2 extraction on macrophage and tumor cell line: the influence of vehicle type. BMC COMPLEMENTARY AND ALTERNATIVE MEDICINE 2015; 15:390. [PMID: 26511466 PMCID: PMC4625945 DOI: 10.1186/s12906-015-0896-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 10/05/2015] [Indexed: 01/24/2023]
Abstract
BACKGROUND Numerous plants from have been investigated due to their anti-inflammatory activity and, among then, extracts or components of ginger (Zingiber officinale Roscoe) and rosemary (Rosmarinus officinalis L.), sources of polyphenolic compounds. 6-gingerol from ginger rhizome and carnosic acid and carnosol from rosemary leaves present anti-tumor, anti-inflammatory and antioxidant activities. However, the evaluation of the mechanisms of action of these and other plant extracts is limited due to their high hydrophobicity. Dimethylsulfoxide (DMSO) is commonly used as a vehicle of liposoluble materials to mammalian cells in vitro, presenting enhanced cell penetration. Liposomes are also able to efficiently deliver agents to mammalian cells, being capable to incorporate in their structure not only hydrophobic molecules, but also hydrophilic and amphiphilic compounds. Another strategy is based on the use of Pluronic F-68, a biocompatible low-foaming, non-ionic surfactant, to disperse hydrophobic components. Here, these three delivery approaches were compared to analyze their influence on the in vitro anti-inflammatory effects of ginger and rosemary extracts, at different concentrations, on primary mammalian cells and on a tumor cell line. METHODS Ginger and rosemary extracts free of organic solvents were obtained by supercritical fluid extraction and dispersed in DMSO, Pluronic F-68 or liposomes, in variable concentrations. Cell viability, production of inflammatory mediators and nitric oxide (NO) release were measured in vitro on J774 cell line and murine macrophages primary culture stimulated with bacterial lipopolysaccharide and interferon-γ after being exposed or not to these extracts. RESULTS Ginger and rosemary extracts obtained by supercritical CO2 extraction inhibited the production of pro-inflammatory cytokines and the release of NO by peritoneal macrophages and J774 cells. The delivery vehicles influenced the anti-inflammatory effects. Comparatively, the ginger extract showed the highest anti-inflammatory activity on the tumor cell line. Controversially, rosemary extract dispersed on DMSO induced a more significant IL-1 and TNF-α reduction than ginger extract in primary macrophages. CONCLUSIONS Amongst the tested delivery vehicles, DMSO was the most suitable, presenting reduced cytotoxicity, followed by Pluronic F-68 and liposomes, provably due to differences in their form of absorption, distribution and cellular metabolism. Co-administration of liposomes and plant extracts may cause death of macrophages cells and induction of NO production. It can be concluded that some of the beneficial effects attributed to extracts of ginger and rosemary may be associated with the inhibition of inflammatory mediators due to their high antioxidant activity. However, these effects were influenced by the type of delivery vehicle.
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Affiliation(s)
- Oselys Rodriguez Justo
- Department of Engineering of Materials and of Bioprocesses - School of Chemical Engineering, University of Campinas, 13083-852, Campinas, SP, Brazil
| | - Patricia Ucelli Simioni
- Department of Genetics, Evolution and Bioagents - Institute of Biology, University of Campinas, 13083-970, Campinas, SP, Brazil
| | - Dirce Lima Gabriel
- Department of Genetics, Evolution and Bioagents - Institute of Biology, University of Campinas, 13083-970, Campinas, SP, Brazil
| | | | - Paulo de Tarso Vieira Rosa
- Departament of Physical Chemistry - Institute of Chemistry, University of Campinas, 13083-970, Campinas, SP, Brazil
| | - Ângela Maria Moraes
- Department of Engineering of Materials and of Bioprocesses - School of Chemical Engineering, University of Campinas, 13083-852, Campinas, SP, Brazil.
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Differential immunomodulatory responses to nine polycyclic aromatic hydrocarbons applied by passive dosing. Toxicol In Vitro 2015; 29:345-51. [DOI: 10.1016/j.tiv.2014.11.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 11/09/2014] [Accepted: 11/18/2014] [Indexed: 01/02/2023]
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Barbosa DJ, Capela JP, de Lourdes Bastos M, Carvalho F. In vitro models for neurotoxicology research. Toxicol Res (Camb) 2015; 4:801-842. [DOI: 10.1039/c4tx00043a] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023] Open
Abstract
The nervous system has a highly complex organization, including many cell types with multiple functions, with an intricate anatomy and unique structural and functional characteristics; the study of its (dys)functionality following exposure to xenobiotics, neurotoxicology, constitutes an important issue in neurosciences.
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Affiliation(s)
- Daniel José Barbosa
- REQUIMTE (Rede de Química e Tecnologia)
- Laboratório de Toxicologia
- Departamento de Ciências Biológicas
- Faculdade de Farmácia
- Universidade do Porto
| | - João Paulo Capela
- REQUIMTE (Rede de Química e Tecnologia)
- Laboratório de Toxicologia
- Departamento de Ciências Biológicas
- Faculdade de Farmácia
- Universidade do Porto
| | - Maria de Lourdes Bastos
- REQUIMTE (Rede de Química e Tecnologia)
- Laboratório de Toxicologia
- Departamento de Ciências Biológicas
- Faculdade de Farmácia
- Universidade do Porto
| | - Félix Carvalho
- REQUIMTE (Rede de Química e Tecnologia)
- Laboratório de Toxicologia
- Departamento de Ciências Biológicas
- Faculdade de Farmácia
- Universidade do Porto
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Rakers S, Imse F, Gebert M. Real-time cell analysis: sensitivity of different vertebrate cell cultures to copper sulfate measured by xCELLigence(®). ECOTOXICOLOGY (LONDON, ENGLAND) 2014; 23:1582-1591. [PMID: 25001081 DOI: 10.1007/s10646-014-1279-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/17/2014] [Indexed: 06/03/2023]
Abstract
In this study, we report the use of a real-time cell analysis (RTCA) test system, the xCELLigence(®) RTCA, as efficient tool for a fast cytotoxicity analysis and comparison of four different vertebrate cell cultures. This new dynamic real-time monitoring and impedance-based assay allows for a combined measurement of cell adhesion, spreading and proliferation. Cell cultures were obtained from mouse, rat, human and fish, all displaying a fibroblast-like phenotype. The measured impedance values could be correlated to characteristic cell culture behaviours. In parallel, relative cytotoxicity of a commonly used but due to its very good water solubility highly hazardous pesticide, copper sulfate, was evaluated under in vitro conditions through measurements of cell viability by classical end-point based assays MTT and PrestoBlue(®). Cell line responses in terms of viability as measured by these three methods were variable between the fish skin cells and cells from higher vertebrates and also between the three methods. The advantage of impedance-based measurements is mainly based on the continuous monitoring of cell responses for a broad range of different cells, including fish cells.
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Affiliation(s)
- S Rakers
- LG Aquatic Cell Technology, Fraunhofer Research Institution for Marine Biotechnology, Paul-Ehrlich-Str. 1-3, 23562, Lübeck, Germany,
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Armitage JM, Wania F, Arnot JA. Application of mass balance models and the chemical activity concept to facilitate the use of in vitro toxicity data for risk assessment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:9770-9. [PMID: 25014875 DOI: 10.1021/es501955g] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Practical, financial, and ethical considerations related to conducting extensive animal testing have resulted in various initiatives to promote and expand the use of in vitro testing data for chemical evaluations. Nominal concentrations in the aqueous phase corresponding to an effect (or biological activity) are commonly reported and used to characterize toxicity (or biological response). However, the true concentration in the aqueous phase can be substantially different from the nominal. To support in vitro test design and aid the interpretation of in vitro toxicity data, we developed a mass balance model that can be parametrized and applied to represent typical in vitro test systems. The model calculates the mass distribution, freely dissolved concentrations, and cell/tissue concentrations corresponding to the initial nominal concentration and experimental conditions specified by the user. Chemical activity, a metric which can be used to assess the potential for baseline toxicity to occur, is also calculated. The model is first applied to a set of hypothetical chemicals to illustrate the degree to which test conditions (e.g., presence or absence of serum) influence the distribution of the chemical in the test system. The model is then applied to set of 1194 real substances (predominantly from the ToxCast chemical database) to calculate the potential range of concentrations and chemical activities under assumed test conditions. The model demonstrates how both concentrations and chemical activities can vary by orders of magnitude for the same nominal concentration.
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Affiliation(s)
- James M Armitage
- Department of Physical and Environmental Sciences, University of Toronto Scarborough , 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada
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Germano D, Uteng M, Pognan F, Chibout SD, Wolf A. Determination of liver specific toxicities in rat hepatocytes by high content imaging during 2-week multiple treatment. Toxicol In Vitro 2014; 30:79-94. [PMID: 24933330 DOI: 10.1016/j.tiv.2014.05.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 05/13/2014] [Accepted: 05/19/2014] [Indexed: 12/26/2022]
Abstract
DILI is a major safety issue during drug development and one of the leading causes for market withdrawal. Despite many efforts made in the past, the prediction of DILI using in vitro models remains very unreliable. In the present study, the well-established hepatocyte Collagen I-Matrigel™ sandwich culture was used, mimicking chronic drug treatment after multiple incubations for 14 days. Ten drugs associated with different types of specific preclinical and clinical liver injury were evaluated at non-cytotoxic concentrations. Mrp2-mediated transport, intracellular accumulation of neutral lipids and phospholipids were selected as functional endpoints by using Cellomics™ Arrayscan® technology and assessed at five timepoints (day 1, 3, 7, 10, 14). Liver specific functional impairments after drug treatment were enhanced over time and could be monitored by HCI already after few days and before cytotoxicity. Phospholipidosis-inducing drugs Chlorpromazine and Amiodarone displayed the same response as in vivo. Cyclosporin A, Chlorpromazine, and Troglitazone inhibited Mrp2-mediated biliary transport, correlating with in vivo findings. Steatosis remained difficult to be reproduced under the current in vitro testing conditions, resulting into false negative and positive responses. The present results suggest that the repeated long-term treatment of rat hepatocytes in the Collagen I-Matrigel™ sandwich configuration might be a suitable tool for safety profiling of the potential to induce phospholipidosis and impair Mrp2-mediated transport processes, but not to predict steatosis.
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Affiliation(s)
- Davide Germano
- Discovery and Investigative Safety, Preclinical Safety, Novartis Institutes for Biomedical Research, CH-4057 Basel, Switzerland
| | - Marianne Uteng
- Discovery and Investigative Safety, Preclinical Safety, Novartis Institutes for Biomedical Research, CH-4057 Basel, Switzerland
| | - Francois Pognan
- Discovery and Investigative Safety, Preclinical Safety, Novartis Institutes for Biomedical Research, CH-4057 Basel, Switzerland
| | - Salah-Dine Chibout
- Discovery and Investigative Safety, Preclinical Safety, Novartis Institutes for Biomedical Research, CH-4057 Basel, Switzerland
| | - Armin Wolf
- Discovery and Investigative Safety, Preclinical Safety, Novartis Institutes for Biomedical Research, CH-4057 Basel, Switzerland.
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Emelogu ES, Seiler TB, Pollard P, Robinson CD, Webster L, McKenzie C, Heger S, Hollert H, Bresnan E, Best J, Moffat CF. Evaluations of combined zebrafish (Danio rerio) embryo and marine phytoplankton (Diacronema lutheri) toxicity of dissolved organic contaminants in the Ythan catchment, Scotland, UK. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2014; 21:5537-5546. [PMID: 24407789 DOI: 10.1007/s11356-013-2488-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 12/20/2013] [Indexed: 06/03/2023]
Abstract
A wide variety of organic contaminants including pesticides, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) have previously been detected in surface waters in the river Ythan catchment, North East Scotland UK. While the concentrations detected were below Water Framework Directive Environmental Quality Standards (WFD-EQSs) environmental exposures to the diverse mixtures of contaminants, known and unknown, may pose chronic and/or sublethal effects to non target organisms. The present study assessed the embryo and algal toxicity potential of freely dissolved organic contaminants from the Ythan catchment using silicone rubber passive sampling devices (SR-PSDs) and miniaturised bioassay techniques. Zebrafish (Danio rerio) embryos and marine phytoplankton species (Diacronema lutheri) were exposed to extracts from SR-PSDs deployed at different locations along the river Ythan and an undeployed procedural blank. Statistically significant developmental and algal toxicities were measured in all tests of extracts from deployed samples compared with the procedural blanks. This indicates environmental exposure to, and the combined toxicity potential of, freely dissolved organic contaminants in the catchment. The present and previous studies in the Ythan catchment, coupling SR-PSDs and bioassay techniques, have both helped to understand the interactions and combined effects of dissolved organic contaminants in the catchment. They have further revealed the need for improvement in the techniques currently used to assess environmental impact.
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Affiliation(s)
- Emmanuel S Emelogu
- Marine Scotland Science, Marine Laboratory, 375 Victoria Road, Aberdeen, AB11 9DB, UK,
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Stadnicka-Michalak J, Tanneberger K, Schirmer K, Ashauer R. Measured and modeled toxicokinetics in cultured fish cells and application to in vitro-in vivo toxicity extrapolation. PLoS One 2014; 9:e92303. [PMID: 24647349 PMCID: PMC3960223 DOI: 10.1371/journal.pone.0092303] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 02/20/2014] [Indexed: 11/18/2022] Open
Abstract
Effect concentrations in the toxicity assessment of chemicals with fish and fish cells are generally based on external exposure concentrations. External concentrations as dose metrics, may, however, hamper interpretation and extrapolation of toxicological effects because it is the internal concentration that gives rise to the biological effective dose. Thus, we need to understand the relationship between the external and internal concentrations of chemicals. The objectives of this study were to: (i) elucidate the time-course of the concentration of chemicals with a wide range of physicochemical properties in the compartments of an in vitro test system, (ii) derive a predictive model for toxicokinetics in the in vitro test system, (iii) test the hypothesis that internal effect concentrations in fish (in vivo) and fish cell lines (in vitro) correlate, and (iv) develop a quantitative in vitro to in vivo toxicity extrapolation method for fish acute toxicity. To achieve these goals, time-dependent amounts of organic chemicals were measured in medium, cells (RTgill-W1) and the plastic of exposure wells. Then, the relation between uptake, elimination rate constants, and log KOW was investigated for cells in order to develop a toxicokinetic model. This model was used to predict internal effect concentrations in cells, which were compared with internal effect concentrations in fish gills predicted by a Physiologically Based Toxicokinetic model. Our model could predict concentrations of non-volatile organic chemicals with log KOW between 0.5 and 7 in cells. The correlation of the log ratio of internal effect concentrations in fish gills and the fish gill cell line with the log KOW was significant (r>0.85, p = 0.0008, F-test). This ratio can be predicted from the log KOW of the chemical (77% of variance explained), comprising a promising model to predict lethal effects on fish based on in vitro data.
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Affiliation(s)
- Julita Stadnicka-Michalak
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
- ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics, Zürich, Switzerland
- EPF Lausanne, School of Architecture, Civil and Environmental Engineering, Lausanne, Switzerland
| | - Katrin Tanneberger
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
- Ecosens AG, Wallisellen, Switzerland
| | - Kristin Schirmer
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
- ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics, Zürich, Switzerland
- EPF Lausanne, School of Architecture, Civil and Environmental Engineering, Lausanne, Switzerland
| | - Roman Ashauer
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
- Environment Department, University of York, Heslington, York, United Kingdom
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Dayeh VR, Bols NC, Tanneberger K, Schirmer K, Lee LEJ. The use of fish-derived cell lines for investigation of environmental contaminants: an update following OECD's fish toxicity testing framework No. 171. ACTA ACUST UNITED AC 2013; Chapter 1:Unit1.5. [PMID: 23670863 DOI: 10.1002/0471140856.tx0105s56] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Protocols for evaluating chemical toxicity at the cellular level using fish cell lines are described in this unit. Routine methodologies for growing salmonid cell lines, and using them in aquatic toxicology studies that support the mandate of the Organization for Economic Co-operation and Development (OECD) to reduce the use of whole animals in toxicity testing, are presented. Rapid, simple, cost-effective tests evaluating viability of cells with three indicator dyes per sample provides a broad overview of the sensitivity of cells to chemical contaminants. This fluorometric assay involves: (1) alamar blue for metabolic activity, (2) CFDA-AM for membrane integrity, and (3) neutral red for lysosomal function. These protocols are conveniently performed in semi-unison within the same multiwell plates and read at three different wavelengths. Detailed step-by-step descriptions of the assays, parameters to consider, troubleshooting, and guidelines for data interpretation are provided as essential tools for investigating environmental aquatic contaminants at the cellular level.
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Affiliation(s)
- Vivian R Dayeh
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
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Scholz S, Sela E, Blaha L, Braunbeck T, Galay-Burgos M, García-Franco M, Guinea J, Klüver N, Schirmer K, Tanneberger K, Tobor-Kapłon M, Witters H, Belanger S, Benfenati E, Creton S, Cronin MT, Eggen RI, Embry M, Ekman D, Gourmelon A, Halder M, Hardy B, Hartung T, Hubesch B, Jungmann D, Lampi MA, Lee L, Léonard M, Küster E, Lillicrap A, Luckenbach T, Murk AJ, Navas JM, Peijnenburg W, Repetto G, Salinas E, Schüürmann G, Spielmann H, Tollefsen KE, Walter-Rohde S, Whale G, Wheeler JR, Winter MJ. A European perspective on alternatives to animal testing for environmental hazard identification and risk assessment. Regul Toxicol Pharmacol 2013; 67:506-30. [DOI: 10.1016/j.yrtph.2013.10.003] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 10/02/2013] [Accepted: 10/16/2013] [Indexed: 12/20/2022]
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Pan T, Khare S, Ackah F, Huang B, Zhang W, Gabos S, Jin C, Stampfl M. In vitro cytotoxicity assessment based on KC50 with real-time cell analyzer (RTCA) assay. Comput Biol Chem 2013; 47:113-20. [DOI: 10.1016/j.compbiolchem.2013.08.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 08/23/2013] [Accepted: 08/23/2013] [Indexed: 11/26/2022]
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Tse ACK, Lau KYT, Ge W, Wu RSS. A rapid screening test for endocrine disrupting chemicals using primary cell culture of the marine medaka. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2013; 144-145:50-58. [PMID: 24140634 DOI: 10.1016/j.aquatox.2013.09.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 09/16/2013] [Accepted: 09/22/2013] [Indexed: 06/02/2023]
Abstract
While endocrine disrupting chemicals (EDCs) pose a significant threat to wildlife worldwide, their diverse chemical structures present a major challenge to their detection, particularly since they are present at very low concentrations in the environment. We here report the development of an in vitro system for rapid screening of EDCs, using primary cell cultures (pituitary, ovarian follicular and testicular cells) of the marine medaka (Oryzias melastigma). Pituitary, testis and ovary cell cultures were developed and challenged by environmentally relevant concentrations of three well known EDCs (viz. estradiol, 2,2',4,4'-tetrabromodiphenyl ether, and 4-n-nonylphenol) as well as hypoxia (which has been shown to be a potent endocrine disruptor). In general, the mRNA expression levels of gonadotropins, their receptors and steroidogenic enzymes exhibited dose response relationships to the four endocrine disruptors in different tissues. The sensitivity and responses were also comparable to in vivo responses of whole fish and in vitro responses of the H295R human adrenocortical cell line. Our results suggest that the use of marine medaka primary cultured cells can serve as a cost effective tool for rapid screening of EDCs in the marine environment, and at the same time, sheds light on the underlying mechanisms of EDCs by deciphering their specific target sites along the hypothalamus-pituitary-gonad axis of vertebrates.
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Affiliation(s)
- Anna C K Tse
- School of Biological Sciences, The University of Hong Kong, Hong Kong
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40
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Stalter D, Dutt M, Escher BI. Headspace-free setup of in vitro bioassays for the evaluation of volatile disinfection by-products. Chem Res Toxicol 2013; 26:1605-14. [PMID: 24117097 DOI: 10.1021/tx400263h] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The conventional setup of in vitro bioassays in microplates does not prevent the loss of volatile compounds, which hampers the toxicological characterization of waterborne volatile disinfection by-products (DBPs). To minimize the loss of volatile test chemicals, we adapted four in vitro bioassays to a headspace-free setup using eight volatile organic compounds (four trihalomethanes, 1,1-dichloroethene, bromoethane, and two haloacetonitriles) that cover a wide range of air-water partition coefficients. The nominal effect concentrations of the test chemicals decreased by up to three orders of magnitude when the conventional setup was changed to a headspace-free setup for the bacterial cytotoxicity assay using bioluminescence inhibition of Vibrio fischeri. The increase of apparent sensitivity correlated significantly with the air-water partition coefficient. Purge and trap GC/MS analysis revealed a reduced loss of dosed volatile compounds in the headspace free setup (78-130% of nominal concentration) compared to a substantial loss in the conventional set up (2-13% of the nominal concentration). The experimental effect concentrations converged with the headspace-free setup to the effect concentrations predicted by a QSAR model, confirming the suitability of the headspace-free approach to minimize the loss of volatile test chemicals. The analogue headspace-free design of the bacterial bioassays for genotoxicity (umuC assay) and mutagenicity (Ames fluctuation assay) increased the number of compounds detected as genotoxic or mutagenic from one to four and zero to two, respectively. In a bioassay with a mammalian cell line applied for detecting the induction of the Nrf-2-mediated oxidative stress response (AREc32 assay), the headspace-free setup improved the apparent sensitivity by less than one order of magnitude, presumably due to the retaining effect of the serum components in the medium, which is also reflected in the reduced aqueous concentrations of compounds. This study highlights the importance of adapting bioanalytical test setups when volatile/semivolatile compounds are present in the sample to avoid the loss of chemicals and thus to avoid underestimating the toxicity of mixtures and complex environmental samples.
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Affiliation(s)
- Daniel Stalter
- National Research Centre for Environmental Toxicology (Entox), The University of Queensland , 39 Kessels Road, Brisbane Qld 4108, Australia
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41
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Groothuis FA, Heringa MB, Nicol B, Hermens JLM, Blaauboer BJ, Kramer NI. Dose metric considerations in in vitro assays to improve quantitative in vitro-in vivo dose extrapolations. Toxicology 2013; 332:30-40. [PMID: 23978460 DOI: 10.1016/j.tox.2013.08.012] [Citation(s) in RCA: 139] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 07/17/2013] [Accepted: 08/14/2013] [Indexed: 12/17/2022]
Abstract
Challenges to improve toxicological risk assessment to meet the demands of the EU chemical's legislation, REACH, and the EU 7th Amendment of the Cosmetics Directive have accelerated the development of non-animal based methods. Unfortunately, uncertainties remain surrounding the power of alternative methods such as in vitro assays to predict in vivo dose-response relationships, which impedes their use in regulatory toxicology. One issue reviewed here, is the lack of a well-defined dose metric for use in concentration-effect relationships obtained from in vitro cell assays. Traditionally, the nominal concentration has been used to define in vitro concentration-effect relationships. However, chemicals may differentially and non-specifically bind to medium constituents, well plate plastic and cells. They may also evaporate, degrade or be metabolized over the exposure period at different rates. Studies have shown that these processes may reduce the bioavailable and biologically effective dose of test chemicals in in vitro assays to levels far below their nominal concentration. This subsequently hampers the interpretation of in vitro data to predict and compare the true toxic potency of test chemicals. Therefore, this review discusses a number of dose metrics and their dependency on in vitro assay setup. Recommendations are given on when to consider alternative dose metrics instead of nominal concentrations, in order to reduce effect concentration variability between in vitro assays and between in vitro and in vivo assays in toxicology.
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Affiliation(s)
- Floris A Groothuis
- Institute for Risk Assessment Sciences, Utrecht University, PO Box 80177, 3508 TD Utrecht, The Netherlands.
| | - Minne B Heringa
- National Institute of Public Health and the Environment (RIVM), PO Box 1, 3720 BA Bilthoven, The Netherlands.
| | - Beate Nicol
- Unilever U.K., Safety & Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedford MK44 1LQ, United Kingdom.
| | - Joop L M Hermens
- Institute for Risk Assessment Sciences, Utrecht University, PO Box 80177, 3508 TD Utrecht, The Netherlands.
| | - Bas J Blaauboer
- Institute for Risk Assessment Sciences, Utrecht University, PO Box 80177, 3508 TD Utrecht, The Netherlands.
| | - Nynke I Kramer
- Institute for Risk Assessment Sciences, Utrecht University, PO Box 80177, 3508 TD Utrecht, The Netherlands.
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42
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In vitro biokinetics of chlorpromazine and the influence of different dose metrics on effect concentrations for cytotoxicity in Balb/c 3T3, Caco-2 and HepaRG cell cultures. Toxicol In Vitro 2013; 27:1057-64. [DOI: 10.1016/j.tiv.2013.01.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 12/24/2012] [Accepted: 01/07/2013] [Indexed: 11/19/2022]
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43
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Pan T, Huang B, Zhang W, Gabos S, Huang DY, Devendran V. Cytotoxicity assessment based on the AUC50 using multi-concentration time-dependent cellular response curves. Anal Chim Acta 2013; 764:44-52. [DOI: 10.1016/j.aca.2012.12.047] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 12/23/2012] [Accepted: 12/28/2012] [Indexed: 01/20/2023]
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44
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Tanneberger K, Knöbel M, Busser FJM, Sinnige TL, Hermens JLM, Schirmer K. Predicting fish acute toxicity using a fish gill cell line-based toxicity assay. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:1110-9. [PMID: 23227966 DOI: 10.1021/es303505z] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The OECD test guideline 203 for determination of fish acute toxicity requires substantial numbers of fish and uses death as an apical end point. One potential alternative are fish cell lines; however, several studies indicated that these appear up to several orders of magnitude less sensitive than fish. We developed a fish gill cell line-based (RTgill-W1) assay, using several measures to improve sensitivity. The optimized assay was applied to determine the toxicity of 35 organic chemicals, having a wide range of toxicity to fish, mode of action and physicochemical properties. We found a very good agreement between in vivo and in vitro effective concentrations. For up to 73% of the tested compounds, the difference between the two approaches was less than 5-fold, covering baseline toxicants but as well compounds with presumed specific modes of action, including reactivity, inhibition of acetylcholine esterase or uncoupling of oxidative phosphorylation. Accounting for measured chemical concentrations eliminated two outliers, the hydrophobic 4-decylaniline and the volatile 2,3-dimethyl-1,3-butadiene, with an outlier being operationally defined as a substance showing a more than 10-fold difference between in vivo/in vitro effect concentrations. Few outliers remained. The most striking were allyl alcohol (2700-fold), which likely needs to be metabolically activated, and permethrin (190-fold) and lindane (63-fold), compounds acting, respectively, on sodium and chloride channels in the brain of fish. We discuss further developments of this assay and suggest its use beyond predicting acute toxicity to fish, for example, as part of adverse outcome pathways to replace, reduce, or refine chronic fish tests.
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Affiliation(s)
- Katrin Tanneberger
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
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45
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Kwon HC, Kwon JH. Measuring aqueous solubility in the presence of small cosolvent volume fractions by passive dosing. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:12550-12556. [PMID: 23088587 DOI: 10.1021/es3035363] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A new passive dosing method was developed to determine aqueous solubility of hydrophobic chemicals. In the passive dosing method, chemical crystals were loaded to a polydimethylsiloxane (PDMS) phase to maintain the maximum chemical activity and to prevent direct contact of chemical crystals with the aqueous solution. Eight polycyclic aromatic hydrocarbons (PAHs) were chosen covering their literature aqueous solubility from 0.001 to 30 mg L(-1). Values of the aqueous solubility for less hydrophobic PAHs (naphthalene, 2-methylnaphthalene, and fluorene) were measured by an Organization for Economic Co-ordination and Development (OECD)-recommended generator column method and those for more hydrophobic PAHs (anthracene, chrysene, and benzo(a)pyrene) were measured by the passive dosing method. For phenanthrene and pyrene, both methods were used for comparison. The results obtained by the passive dosing method were very close to those obtained by the generator column method. Aqueous solubilities in deionized water for more hydrophobic PAHs obtained using the passive dosing method agreed very well with values reported in the literature, suggesting the utility of the passive dosing method for the determination of aqueous solubility for highly hydrophobic chemicals. Because hydrophobic chemicals are often introduced in aqueous solutions by using a cosolvent, the solubility enhancement for PAHs at low cosolvent volume fractions was also evaluated. Three cosolvents (dimethyl sulfoxide, ethanol, and acetone) were chosen and their volume fractions in water were between 0.2% and 2%. The enhancement of the aqueous solubility could be well explained quantitatively by using a log-linear cosolvency model. The measured values of cosolvency power at the range of volume fraction investigated (σ(0.02)) correlated very well with log K(ow) of the PAHs. The combination of the log-linear model and semiempirical relationships between σ(0.02) and log K(ow) would be useful for the prediction of the solubility enhancement of hydrophobic chemicals.
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Affiliation(s)
- Hyuck-Chul Kwon
- Department of Environmental Engineering, Ajou University, Woncheondong, Yeongtonggu, Suwon 443-749, Republic of Korea
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46
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Knöbel M, Busser FJM, Rico-Rico A, Kramer NI, Hermens JLM, Hafner C, Tanneberger K, Schirmer K, Scholz S. Predicting adult fish acute lethality with the zebrafish embryo: relevance of test duration, endpoints, compound properties, and exposure concentration analysis. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:9690-700. [PMID: 22835061 DOI: 10.1021/es301729q] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The zebrafish embryo toxicity test has been proposed as an alternative for the acute fish toxicity test, which is required by various regulations for environmental risk assessment of chemicals. We investigated the reliability of the embryo test by probing organic industrial chemicals with a wide range of physicochemical properties, toxicities, and modes of toxic action. Moreover, the relevance of using measured versus nominal (intended) exposure concentrations, inclusion of sublethal endpoints, and different exposure durations for the comparability with reported fish acute toxicity was explored. Our results confirm a very strong correlation of zebrafish embryo to fish acute toxicity. When toxicity values were calculated based on measured exposure concentrations, the slope of the type II regression line was 1 and nearly passed through the origin (1 to 1 correlation). Measured concentrations also explained several apparent outliers. Neither prolonged exposure (up to 120 h) nor consideration of sublethal effects led to a reduced number of outliers. Yet, two types of compounds were less lethal to embryos than to adult fish: a neurotoxic compound acting via sodium channels (permethrin) and a compound requiring metabolic activation (allyl alcohol).
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Affiliation(s)
- Melanie Knöbel
- Eawag-Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, 8600 Dübendorf, Switzerland.
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Coecke S, Pelkonen O, Leite SB, Bernauer U, Bessems JG, Bois FY, Gundert-Remy U, Loizou G, Testai E, Zaldívar JM. Toxicokinetics as a key to the integrated toxicity risk assessment based primarily on non-animal approaches. Toxicol In Vitro 2012; 27:1570-7. [PMID: 22771339 DOI: 10.1016/j.tiv.2012.06.012] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 03/09/2012] [Accepted: 06/22/2012] [Indexed: 02/02/2023]
Abstract
Toxicokinetics (TK) is the endpoint that informs about the penetration into and fate within the body of a toxic substance, including the possible emergence of metabolites. Traditionally, the data needed to understand those phenomena have been obtained in vivo. Currently, with a drive towards non-animal testing approaches, TK has been identified as a key element to integrate the results from in silico, in vitro and already available in vivo studies. TK is needed to estimate the range of target organ doses that can be expected from realistic human external exposure scenarios. This information is crucial for determining the dose/concentration range that should be used for in vitro testing. Vice versa, TK is necessary to convert the in vitro results, generated at tissue/cell or sub-cellular level, into dose response or potency information relating to the entire target organism, i.e. the human body (in vitro-in vivo extrapolation, IVIVE). Physiologically based toxicokinetic modelling (PBTK) is currently regarded as the most adequate approach to simulate human TK and extrapolate between in vitro and in vivo contexts. The fact that PBTK models are mechanism-based which allows them to be 'generic' to a certain extent (various extrapolations possible) has been critical for their success so far. The need for high-quality in vitro and in silico data on absorption, distribution, metabolism as well as excretion (ADME) as input for PBTK models to predict human dose-response curves is currently a bottleneck for integrative risk assessment.
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Affiliation(s)
- Sandra Coecke
- ECVAM, Institute for Health & Consumer Protection, European Commission Joint Research Centre, 21027 Ispra (VA), Italy
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Localization of breast cancer resistance protein (Bcrp) in endocrine organs and inhibition of its transport activity by steroid hormones. Cell Tissue Res 2012; 349:551-63. [PMID: 22581381 PMCID: PMC3414710 DOI: 10.1007/s00441-012-1417-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 03/27/2012] [Indexed: 01/16/2023]
Abstract
Breast cancer resistance protein (BCRP) is known for its protective function against the toxic effects of exogenous compounds. In addition to this, a role in the transport of endogenous compounds has been described. Since BCRP in the plasma membrane was shown to be regulated by sex steroids, we investigated the presence and possible role of BCRP in steroid hormone-producing organs. Therefore, the presence and localization of Bcrp was investigated in endocrine organs of wild-type mice. Furthermore, the interaction of various steroid hormones with human BCRP activity was studied. Quantitative PCR revealed Bcrp mRNA in the pituitary and adrenal glands, pancreas, ovary, testis and adipose tissue. Immunohistochemistry revealed the presence of Bcrp in the cortex of the adrenal gland and in plasma membranes of adipocytes. In the pituitary gland, pancreas, ovary and testis, Bcrp was mainly located in the capillaries. The interaction between BCRP and 12 steroid hormones was studied using membrane vesicles of HEK293-BCRP cells. Estradiol, testosterone, progesterone and androstenedione inhibited BCRP-mediated uptake of 3H-estrone sulphate (E1S) most potently, with calculated inhibitory constant (Ki) values of 5.0 ± 0.2, 36 ± 14, 14.7 ± 1.3 and 217 ± 13 μM, respectively. BCRP function was attenuated non-competitively, which implies an allosteric inhibition of BCRP-mediated E1S transport by these steroids. In conclusion, localization of Bcrp in endocrine organs together with the efficient allosteric inhibition of the efflux pump by steroid hormones are suggestive for a role for BCRP in steroid hormone regulation.
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Stadnicka J, Schirmer K, Ashauer R. Predicting concentrations of organic chemicals in fish by using toxicokinetic models. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:3273-80. [PMID: 22324398 PMCID: PMC3308199 DOI: 10.1021/es2043728] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Quantification of chemical toxicity continues to be generally based on measured external concentrations. Yet, internal chemical concentrations have been suggested to be a more suitable parameter. To better understand the relationship between the external and internal concentrations of chemicals in fish, and to quantify internal concentrations, we compared three toxicokinetic (TK) models with each other and with literature data of measured concentrations of 39 chemicals. Two one-compartment models, together with the physiologically based toxicokinetic (PBTK) model, in which we improved the treatment of lipids, were used to predict concentrations of organic chemicals in two fish species: rainbow trout (Oncorhynchus mykiss) and fathead minnow (Pimephales promelas). All models predicted the measured internal concentrations in fish within 1 order of magnitude for at least 68% of the chemicals. Furthermore, the PBTK model outperformed the one-compartment models with respect to simulating chemical concentrations in the whole body (at least 88% of internal concentrations were predicted within 1 order of magnitude using the PBTK model). All the models can be used to predict concentrations in different fish species without additional experiments. However, further development of TK models is required for polar, ionizable, and easily biotransformed compounds.
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Affiliation(s)
- Julita Stadnicka
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland.
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Kwon HC, Roh JY, Lim D, Choi J, Kwon JH. Maintaining the Constant Exposure Condition for an Acute Caenorhabditis elegans Mortality Test Using Passive Dosing. ENVIRONMENTAL HEALTH AND TOXICOLOGY 2011; 26:e2011015. [PMID: 22125776 PMCID: PMC3214985 DOI: 10.5620/eht.2011.26.e2011015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 09/28/2011] [Indexed: 05/31/2023]
Abstract
OBJECTIVES Maintaining the constant exposure to hydrophobic organic compouds in acute toxicity tests is one of the most difficult issues in the evaluation of their toxicity and corresponding risks. Passive dosing is an emerging tool to keep constant aqueous concentration because of the overwhelming mass loaded in the dosing phase. The primary objectives of this study were to develop the constant exposure condition for an acute mortality test and to compare the performance of the passive dosing method with the conventional spiking with co-solvent. METHODS A custom cut polydimethylsiloxane (PDMS) tubing loaded with benzyl butyl phthalate (BBP) was placed in each well of a 24-well plate containing assay medium. The rate of the release of BBP from PDMS was evaluated by measuring the change in the concentration of BBP in the assay medium. The efficiency of maintaining constant exposure condition was also evaluated using a simple two-compartment mass transport model employing a film-diffusion theory. An acute mortality test using 10 C. elegans in each well was conducted for the evaluation of the validity of passive dosing and the comparative evaluation of the passive dosing method and the conventional spiking method. RESULTS Free concentration in the assay medium reached 95% steady state value within 2.2 hours without test organisms, indicating that this passive dosing method is useful for an acute toxicity test in 24 hours. The measured concentration after the mortality test agreed well with the estimated values from partitioning between PDMS and the assay medium. However, the difference between the nominal and the free concentration became larger as the spiked concentration approached water solubility, indicating the instability of the conventional spiking with a co-solvent. CONCLUSIONS The results in this study support that passive dosing provides a stable exposure condition for an acute toxicity test. Thus, it is likely that more reliable toxicity assessment can be made for hydrophobic chemicals using passive dosing.
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Affiliation(s)
- Hyuck-Chul Kwon
- Department of Environmental Engineering, Ajou University, Suwon, Korea
| | - Ji-Yeon Roh
- Faculty of Environmental Engineering, University of Seoul, Seoul, Korea
| | - Dongyoung Lim
- Faculty of Environmental Engineering, University of Seoul, Seoul, Korea
| | - Jinhee Choi
- Faculty of Environmental Engineering, University of Seoul, Seoul, Korea
| | - Jung-Hwan Kwon
- Department of Environmental Engineering, Ajou University, Suwon, Korea
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