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Clippinger AJ, Raabe HA, Allen DG, Choksi NY, van der Zalm AJ, Kleinstreuer NC, Barroso J, Lowit AB. Human-relevant approaches to assess eye corrosion/irritation potential of agrochemical formulations. Cutan Ocul Toxicol 2021; 40:145-167. [PMID: 33830843 DOI: 10.1080/15569527.2021.1910291] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
There are multiple in vitro and ex vivo eye irritation and corrosion test methods that are available as internationally harmonized test guidelines for regulatory use. Despite their demonstrated usefulness to a broad range of substances through inter-laboratory validation studies, they have not been widely adopted for testing agrochemical formulations due to a lack of concordance with parallel results from the traditional regulatory test method for this endpoint, the rabbit eye test. The inherent variability of the rabbit test, differences in the anatomy of the rabbit and human eyes, and differences in modelling exposures in rabbit eyes relative to human eyes contribute to this lack of concordance. Ultimately, the regulatory purpose for these tests is protection of human health, and, thus, there is a need for a testing approach based on human biology. This paper reviews the available in vivo, in vitro and ex vivo test methods with respect to their relevance to human ocular anatomy, anticipated exposure scenarios, and the mechanisms of eye irritation/corrosion in humans. Each of the in vitro and ex vivo methods described is generally appropriate for identifying non-irritants. To discriminate among eye irritants, the human three-dimensional epithelial and full thickness corneal models provide the most detailed information about the severity of irritation. Consideration of the mechanisms of eye irritation, and the strengths and limitations of the in vivo, in vitro and ex vivo test methods, show that the in vitro/ex vivo methods are as or more reflective of human biology and less variable than the currently used rabbit approach. Suggestions are made for further optimizing the most promising methods to distinguish between severe (corrosive), moderate, mild and non-irritants and provide information about the reversibility of effects. Also considered is the utility of including additional information (e.g. physical chemical properties), consistent with the Organization for Economic Cooperation and Development's guidance document on an integrated approach to testing and assessment of potential eye irritation. Combining structural and functional information about a test substance with test results from human-relevant methods will ensure the best protection of humans following accidental eye exposure to agrochemicals.
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Affiliation(s)
| | - Hans A Raabe
- Institute for In Vitro Sciences, Inc., Gaithersburg, MD, USA
| | - David G Allen
- Integrated Laboratory Systems, LLC, Research Triangle Park, NC, USA
| | - Neepa Y Choksi
- Integrated Laboratory Systems, LLC, Research Triangle Park, NC, USA
| | | | - Nicole C Kleinstreuer
- National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - João Barroso
- European Commission, Joint Research Centre (JRC), Ispra, VA, Italy
| | - Anna B Lowit
- US Environmental Protection Agency Office of Pesticide Programs, Washington, DC, USA
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2
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Budai P, Kormos É, Buda I, Somody G, Lehel J. Comparative evaluation of HET-CAM and ICE methods for objective assessment of ocular irritation caused by selected pesticide products. Toxicol In Vitro 2021; 74:105150. [PMID: 33753176 DOI: 10.1016/j.tiv.2021.105150] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 03/15/2021] [Accepted: 03/17/2021] [Indexed: 01/29/2023]
Abstract
Eye irritation potency of pesticides (fungicides, herbicides, insecticides) was comparatively tested by HET-CAM and ICE method. Based on the results of the tests the statistical analysis of agreement between classification using individual methods was done by Goodman-Kruskal's rank correlation and determination (calculation) of Cohen's kappa coefficient. Statistical analysis of agreement between classification revealed significant correlation between results of in vivo and in HET-CAM assays (76%). There was no significant correlation between result of in vivo and in ICE methods (64%). Weakest correlation was found between the data from in vitro HET-CAM and ICE tests. The percentage of agreement between two in vitro data was 48%. They may be recommended as a part of a battery of tests to reduce experimentation on mammals and to limit or eliminate pain and injury inflicted on experimental animals. The HET-CAM test is a useful tool for studying in vivo the potential conjunctival irritation, while the ICE test can be used to study corneal irritant effects in detail.
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Affiliation(s)
- Péter Budai
- Georgikon Campus, Hungarian University of Agriculture and Life Sciences, Hungary.
| | - Éva Kormos
- Georgikon Campus, Hungarian University of Agriculture and Life Sciences, Hungary
| | - István Buda
- Georgikon Campus, Hungarian University of Agriculture and Life Sciences, Hungary
| | - Gergő Somody
- Georgikon Campus, Hungarian University of Agriculture and Life Sciences, Hungary
| | - József Lehel
- University of Veterinary Medicine Budapest, Hungary.
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3
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In vitro reconstructed 3D corneal tissue models for ocular toxicology and ophthalmic drug development. In Vitro Cell Dev Biol Anim 2021; 57:207-237. [PMID: 33544359 DOI: 10.1007/s11626-020-00533-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 11/18/2020] [Indexed: 12/13/2022]
Abstract
Testing of all manufactured products and their ingredients for eye irritation is a regulatory requirement. In the last two decades, the development of alternatives to the in vivo Draize eye irritation test method has substantially advanced due to the improvements in primary cell isolation, cell culture techniques, and media, which have led to improved in vitro corneal tissue models and test methods. Most in vitro models for ocular toxicology attempt to reproduce the corneal epithelial tissue which consists of 4-5 layers of non-keratinized corneal epithelial cells that form tight junctions, thereby limiting the penetration of chemicals, xenobiotics, and pharmaceuticals. Also, significant efforts have been directed toward the development of more complex three-dimensional (3D) equivalents to study wound healing, drug permeation, and bioavailability. This review focuses on in vitro reconstructed 3D corneal tissue models and their utilization in ocular toxicology as well as their application to pharmacology and ophthalmic research. Current human 3D corneal epithelial cell culture models have replaced in vivo animal eye irritation tests for many applications, and substantial validation efforts are in progress to verify and approve alternative eye irritation tests for widespread use. The validation of drug absorption models and further development of models and test methods for many ophthalmic and ocular disease applications is required.
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4
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Muir CK. Qualitative Differences in Opacification and Thickness of Bovine Cornea In Vitro Induced by Acid, Alkali, Surfactant or Methanol. Altern Lab Anim 2020. [DOI: 10.1177/026119298701400403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Bovine corneas incubated at pH 2 for 4.5 hours became opaque but did not thicken. Corneas incubated at pH 12 became opaque and thickened. Removal of epithelium indicated that pH 2 had caused opacity predominantly in the epithelium itself, while pH 12 had predominantly opacified the stroma. With 5 x 10-3 M of the cationic surfactant, lauryl trimethylammonium bromide, in contact only with the outside (epithelium-side) of the cornea for up to 4 hours, the epithelium opacified but the stroma did not. There was no thickening for the first 2 hours of incubation, but significant thickening thereafter. Methanol 50% v/v in contact only with the outside of the cornea caused the epithelium to opacify within 2 minutes, but this effect diminished and a profound opacification of stroma developed over 4 hours. Gross thickening to over three times normal had developed after 4 hours of incubation. The results suggest that opacity can occur without thickening, but that thickening cannot occur without opacity. Opacity may therefore be a more reliable parameter than thickness for indicating toxic responses of the cornea.
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Affiliation(s)
- Colin K. Muir
- Department of Pharmacology, School of Pharmacy, Leicester Polytechnic, Leicester LE1 9BH, UK
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5
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Cornells M, Dupont C, Wepierre J. In VitroCytotoxicity Tests on Cultured Human Skin Fibroblasts to Predict the Irritation Potential of Surfactants. Altern Lab Anim 2020. [DOI: 10.1177/026119299101900306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A comparative study of the cytotoxicity of 17 surfactants was performed in vitro on cultured human skin fibroblasts to predict their irritation potential under different experimental conditions: test media, presence of proteins, various times of exposure (2–72 hours), and evaluation methods. For cytotoxicity, the tetrazolium MTT assay after exposure for 2 hours in Hank's medium (HBSS) seemed to be more sensitive than protein and LDH leakage tests. Cytotoxicities in HBSS and in minimum Eagle's medium (MEM) were very similar. Addition of 10% fetal calf serum (FCS) to MEM decreased the cytotoxicity of surfactants; however, their order of cytotoxicity was generally the same in MEM with or without FCS. Cytotoxicity increased with incubation time, but the overall ranking remained identical. Non-ionic polyoxyethylene 20 ethers (Brij 35, 58, 78 and 99) surfactants, although considered to be non-irritant in vivo, revealed a high cytotoxic effect in our cell culture system. A good correlation with the results of in vivo Draize rabbit eye irritancy was found only when they were excluded.
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Affiliation(s)
- Marleen Cornells
- Laboratoire de Pharmacologic, Unité de Dermopharmacologie, URA CNRS 594, Faculté de Pharmacie, Université Paris Sud, Rue J.B. Clément, 99296 Châtenay-Malabry, France
| | - Charlotte Dupont
- Laboratoire de Pharmacologic, Unité de Dermopharmacologie, URA CNRS 594, Faculté de Pharmacie, Université Paris Sud, Rue J.B. Clément, 99296 Châtenay-Malabry, France
| | - Jacques Wepierre
- Laboratoire de Pharmacologic, Unité de Dermopharmacologie, URA CNRS 594, Faculté de Pharmacie, Université Paris Sud, Rue J.B. Clément, 99296 Châtenay-Malabry, France
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6
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Balls M, Atkinson KA, Gordon VC. Complementation in the Development, Validation and Use of Non-animal Test Batteries, with Particular Reference to Ocular Irritancy. Altern Lab Anim 2020. [DOI: 10.1177/026119299101900406] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Michael Balls
- The FRAME Alternatives Laboratory, Department of Human Morphology, University of Nottingham Medical School, Nottingham NG7 2UH, UK
| | - Karen A. Atkinson
- The FRAME Alternatives Laboratory, Department of Human Morphology, University of Nottingham Medical School, Nottingham NG7 2UH, UK
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Barratt MD. The Role of Structure-activity Relationships and Expert Systems in Alternative Strategies for the Determination of Skin Sensitisation, Skin Corrosivity and Eye Irritation. Altern Lab Anim 2020. [DOI: 10.1177/026119299502300114] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A historical database containing the results of 294 defined single substances tested in the guinea-pig maximisation test, carried out according to a single protocol, was used to derive a set of structural alerts for skin sensitisation, which have been incorporated into the expert system, DEREK. Together with an assessment of percutaneous absorption, this system forms an integral part of a strategic approach to the identification of contact allergens. Quantitative structure-activity relationships (QSARs) were derived for the skin corrosivity of organic acids and bases, and for the eye irritation potential of neutral organic chemicals. The independent variables used for these analyses were selected on the basis of the putative mechanisms for skin irritation or corrosivity and for eye irritation, respectively. Data sets were analysed using principal components analysis; plots of the first two principal components for each data set showed that the analyses were able to discriminate well between chemicals with different classifications of toxicological activity. The derived QSARs are expected to give useful predictions of skin corrosivity and eye irritancy for new or untested chemicals in these classes. Although the development of these techniques is still at a very early stage, they are already able to play an important part in proposed strategies for the reduction of experimental animal usage. In the long term, it should be possible to conduct safety evaluations using fewer experimental animals or no animals at all. However, acceptance by regulatory authorities will be a key factor in realising the full benefits of the approach.
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Affiliation(s)
- Martin D. Barratt
- Unilever Environmental Safety Laboratory, Colworth House, Sharnbrook, Bedford MK44 1LQ, UK
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8
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Wilcox DK, Bruner LH. In Vitro Alternatives for Ocular Safety Testing: An Outline of Assays and Possible Future Developments. Altern Lab Anim 2020. [DOI: 10.1177/026119299001800115.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
An increasing number of in vitro tests are being proposed as alternatives for animals in ocular safety testing. These in vitro systems use a variety of approaches and measure a broad range of endpoints, including cellular cytotoxicity and metabolism. We will briefly review the development and validation of these model systems. Several tests appear promising, and may prove useful as adjuncts in our current ocular safety assessment schemes. We will also discuss how these tests can most rapidly be brought to use in ocular safety assessment, and where efforts should be directed to develop more-highly predictive in vitro model systems for the future.
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Affiliation(s)
- David K. Wilcox
- Human & Environmental Safety Division, The Procter & Gamble Company, Miami Valley Laboratories, Cincinnati, OH 45239-8707, USA
| | - Leon H. Bruner
- Human & Environmental Safety Division, The Procter & Gamble Company, Miami Valley Laboratories, Cincinnati, OH 45239-8707, USA
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9
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Balls M, Fentem JH. The Use of Basal Cytotoxicity and Target Organ Toxicity Tests in Hazard Identification and Risk Assessment. Altern Lab Anim 2020. [DOI: 10.1177/026119299202000304] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Non-animal procedures, including in vitro test systems and test strategies, can already make a significant contribution to the background to risk assessment — in predicting both the toxic potential and toxic potency of chemicals, as well as, in some circumstances, the toxic hazard they may represent under specified conditions of exposure. They can be particularly useful for investigating molecular and cellular mechanisms of chemical-induced toxicity, and for identifying species-specific effects, which greatly limit the value of data from laboratory animal studies in the human risk assessment process. Attention is focused on the need for greater effort to be invested in the development of non-animal procedures for evaluating the biokinetic factors which will determine the ultimate form and concentration of a particular chemical at possible sites of toxic action. The relative merits of correlative and mechanistic approaches to test development and test validation are discussed. The need for realism is emphasised, not only in relation to our expectations of the validation process, but also in terms of the current and future status of regulatory toxicology, in vitro or in vivo, as a scientific discipline. Finally, it is concluded that the intelligent and strategic use of in vitro test systems, in conjunction with predictive computer modelling, could markedly improve the scientific basis of human risk assessment.
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Affiliation(s)
- Michael Balls
- FRAME (Fund for the Replacement of Animals in Medical Experiments), 34 Stoney Street, Nottingham NG1 1NB, UK, and Department of Human Morphology, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Julia H. Fentem
- FRAME (Fund for the Replacement of Animals in Medical Experiments), 34 Stoney Street, Nottingham NG1 1NB, UK, and Department of Human Morphology, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK
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10
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Clothier RH, Atkinson KA, Garle MJ, Ward RK, Willshaw A. The Development and Evaluation of In Vitro Tests by the FRAME Alternatives Laboratory. Altern Lab Anim 2020. [DOI: 10.1177/026119299502300111] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This review outlines the work which has been conducted in the FRAME Alternatives Laboratory during the first ten years of the FRAME Research Programme. A number of in vitro tests, including the kenacid blue, neutral red release and fluorescein leakage assay methods, have been evaluated and have subsequently been included in validation schemes organised by the US Soap and Detergent Association, the US Cosmetic, Toiletry and Fragrance Association, the European Commission and the European Cosmetic, Toiletry and Perfumery Association, as well as in the Scandinavian multicentre evaluation of in vitro cytotoxicity testing scheme. More recently, research has been undertaken in the areas of phototoxicity, immunotoxicity, dermal toxicity and intercellular communication, in addition to investigations into fundamental mechanisms of toxicity.
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Affiliation(s)
- Richard H. Clothier
- FRAME Alternatives Laboratory, Department of Human Morphology, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Karen A. Atkinson
- FRAME Alternatives Laboratory, Department of Human Morphology, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Michael J. Garle
- FRAME Alternatives Laboratory, Department of Human Morphology, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Rachel K. Ward
- FRAME Alternatives Laboratory, Department of Human Morphology, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Angela Willshaw
- FRAME Alternatives Laboratory, Department of Human Morphology, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK
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11
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Shaw AJ, Clothier RH, Balls M. Loss of Trans-epithelial Impermeability of a Confluent Monolayer of Madin-Darby Canine Kidney (MDCK) Cells as a Determinant of Ocular Irritancy Potential. Altern Lab Anim 2020. [DOI: 10.1177/026119299001800117.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The short-term exposure of a confluent layer of MDCK cells to a series of test agents of varying ocular irritancy potential demonstrated that the tight junctions between these cells were affected in such a way that fluorescein could leak through in a dose-related manner. Rankings of test agents in order of potency to promote “fluorescein leakage” correlated well with neutral red release results (r=0.98) and ranked toxicity closely with in vivo eye irritancy data. However, the neutral red release assay produced negative results for three inorganic irritants, whereas these were detected using the fluorescein leakage assay.
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Affiliation(s)
- Andrew J. Shaw
- Department of Human Morphology, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Richard H. Clothier
- Department of Human Morphology, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Michael Balls
- Department of Human Morphology, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK
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12
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Reader SJ, Blackwell V, O'Hara R, Clothier RH, Griffin G, Balls M. A Vital Dye Release Method for Assessing the Short-term Cytotoxic Effects of Chemicals and Formulations. Altern Lab Anim 2020. [DOI: 10.1177/026119298901700106] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Sandra J. Reader
- Department of Human Morphology, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Verity Blackwell
- Department of Human Morphology, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Richard O'Hara
- Department of Human Morphology, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Richard H. Clothier
- Department of Human Morphology, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Gilly Griffin
- Department of Human Morphology, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Michael Balls
- Department of Human Morphology, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK
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13
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Kim TW, Che JH, Yun JW. Use of stem cells as alternative methods to animal experimentation in predictive toxicology. Regul Toxicol Pharmacol 2019; 105:15-29. [DOI: 10.1016/j.yrtph.2019.03.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 03/23/2019] [Accepted: 03/25/2019] [Indexed: 12/16/2022]
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14
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Eskes C, Bessou S, Bruner L, Curren R, Harbell J, Jones P, Kreiling R, Liebsch M, McNamee P, Pape W, Prinsen MK, Seidle T, Vanparys P, Worth A, Zuang V. 3.3. Eye Irritation. Altern Lab Anim 2019; 33 Suppl 1:47-81. [PMID: 16194141 DOI: 10.1177/026119290503301s09] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Chantra Eskes
- ECVAM, Institute for Health and Consumer Protection, European Commission Joint Research Centre, Ispra (VA), Italy
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15
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16
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Microfluidic Devices for Eye Irritation Tests of Cosmetics and Cosmetic Ingredients. BIOCHIP JOURNAL 2019. [DOI: 10.1007/s13206-018-3204-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Lee M, Hwang JH, Lim KM. Alternatives to In Vivo Draize Rabbit Eye and Skin Irritation Tests with a Focus on 3D Reconstructed Human Cornea-Like Epithelium and Epidermis Models. Toxicol Res 2017; 33:191-203. [PMID: 28744350 PMCID: PMC5523559 DOI: 10.5487/tr.2017.33.3.191] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 06/13/2017] [Accepted: 06/14/2017] [Indexed: 12/25/2022] Open
Abstract
Human eyes and skin are frequently exposed to chemicals accidentally or on purpose due to their external location. Therefore, chemicals are required to undergo the evaluation of the ocular and dermal irritancy for their safe handling and use before release into the market. Draize rabbit eye and skin irritation test developed in 1944, has been a gold standard test which was enlisted as OECD TG 404 and OECD TG 405 but it has been criticized with respect to animal welfare due to invasive and cruel procedure. To replace it, diverse alternatives have been developed: (i) For Draize eye irritation test, organotypic assay, in vitro cytotoxicity-based method, in chemico tests, in silico prediction model, and 3D reconstructed human cornea-like epithelium (RhCE); (ii) For Draize skin irritation test, in vitro cytotoxicity-based cell model, and 3D reconstructed human epidermis models (RhE). Of these, RhCE and RhE models are getting spotlight as a promising alternative with a wide applicability domain covering cosmetics and personal care products. In this review, we overviewed the current alternatives to Draize test with a focus on 3D human epithelium models to provide an insight into advancing and widening their utility.
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Affiliation(s)
| | | | - Kyung-Min Lim
- College of Pharmacy, Ewha Womans University, Seoul,
Korea
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18
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Prinsen MK, Hendriksen CF, Krul CA, Woutersen RA. The Isolated Chicken Eye test to replace the Draize test in rabbits. Regul Toxicol Pharmacol 2017; 85:132-149. [DOI: 10.1016/j.yrtph.2017.01.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 01/27/2017] [Indexed: 10/20/2022]
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19
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Muir CK, Flower C, Van Abbé NJ. The Effect of Shampoos on Rabbit Ileum in Vitro Compared to Eye Irritancy in Vivo. ACTA ACUST UNITED AC 2016. [DOI: 10.3109/10915818609141015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The concentrations of 5 antidandruff, 7 adult, and 11 baby shampoos required to block spontaneous contractions of rabbit isolated ileum by 50% (EC50) in vitro were determined. In general, antidandruff shampoos were the most potent and baby shampoos least potent in this test. The in vitro ileum EC50s for antidandruff and adult shampoos correlated well with ocular irritancy determined in vivo from samples diluted to 20%. Correlation between in vitro ileum EC50s and in vivo irritancy was poor for baby shampoos, but in vivo irritancy for these samples was barely detectable 24 hours after instillation. The findings suggest that the ileum model may be useful as a possible alternative to in vivo testing for some formulated products, particularly where in vivo irritancy might be more than minimal.
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Affiliation(s)
- C. K. Muir
- Beecham Products Research Department St. Georges Avenue Weybridge Surrey, KT13 ODE England
| | - C. Flower
- Beecham Products Research Department St. Georges Avenue Weybridge Surrey, KT13 ODE England
| | - N. J. Van Abbé
- Beecham Products Research Department St. Georges Avenue Weybridge Surrey, KT13 ODE England
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20
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Christian MS, Diener RM. Soaps and Detergents: Alternatives to Animal Eye Irritation Tests. ACTA ACUST UNITED AC 2016. [DOI: 10.3109/10915819609008705] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
An extensive computer search was conducted, and a comprehensive overview of the current status of alternatives to animal eye irritation tests was obtained. A search of Medline and Toxline databases (1988 to present) was supplemented with references from sources regarding in vitro eye irritation. Particular attention was paid to soap and detergent products and related ingredients. Eighty-five references are included in the review; the in vitro assays are categorized, and their predictive values for assessing acute ocular irritation are evaluated and compared with the Draize rabbit eye irritation assay and with each other. The present review shows that the increased activity of scientists from academia, industry, and regulatory agencies has resulted in substantial progress in developing alternative in vitro procedures and that a number of large, interlaboratory evaluations and international workshops have assisted in the selection process. However, none of these methodologies has obtained acceptance for regulatory classification purposes. Conclusions drawn from this review include that (a) no single in vitro assay is considered capable of replacing the Draize eye irritation test; (b) the chorioallantoic membrane vascular assay (CAMVA) or the hen egg test-chorio-allantoic membrane test (HET-CAM), the chicken or bovine enucleated eye test, the neutral red and plasminogen activation assays for cytotoxicity, and the silicon microphysiometer appear to have the greatest potential as screening tools for eye irritation; and (c) choosing a specific assay or series of assays will depend on the type of agent tested and the impact of false-negative or false-positive results. New assays will continue to be developed and should be included in future evaluations, when sufficient data are available.
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21
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Shafaie S, Hutter V, Cook MT, Brown MB, Chau DYS. In Vitro Cell Models for Ophthalmic Drug Development Applications. Biores Open Access 2016; 5:94-108. [PMID: 27158563 PMCID: PMC4845647 DOI: 10.1089/biores.2016.0008] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Tissue engineering is a rapidly expanding field that aims to establish feasible techniques to fabricate biologically equivalent replacements for diseased and damaged tissues/organs. Emerging from this prospect is the development of in vitro representations of organs for drug toxicity assessment. Due to the ever-increasing interest in ocular drug delivery as a route for administration as well as the rise of new ophthalmic therapeutics, there is a demand for physiologically accurate in vitro models of the eye to assess drug delivery and safety of new ocular medicines. This review summarizes current existing ocular models and highlights the important factors and limitations that need to be considered during their use.
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Affiliation(s)
- Sara Shafaie
- Department of Pharmacy, Pharmacology, and Postgraduate Medicine, The Research Center in Topical Drug Delivery and Toxicology, School of Life and Medical Sciences, University of Hertfordshire , Hertfordshire, United Kingdom
| | - Victoria Hutter
- Department of Pharmacy, Pharmacology, and Postgraduate Medicine, The Research Center in Topical Drug Delivery and Toxicology, School of Life and Medical Sciences, University of Hertfordshire , Hertfordshire, United Kingdom
| | - Michael T Cook
- Department of Pharmacy, Pharmacology, and Postgraduate Medicine, The Research Center in Topical Drug Delivery and Toxicology, School of Life and Medical Sciences, University of Hertfordshire , Hertfordshire, United Kingdom
| | - Marc B Brown
- Department of Pharmacy, Pharmacology, and Postgraduate Medicine, The Research Center in Topical Drug Delivery and Toxicology, School of Life and Medical Sciences, University of Hertfordshire, Hertfordshire, United Kingdom.; MedPharm Ltd., Guildford, Surrey, United Kingdom
| | - David Y S Chau
- Department of Pharmacy, Pharmacology, and Postgraduate Medicine, The Research Center in Topical Drug Delivery and Toxicology, School of Life and Medical Sciences, University of Hertfordshire , Hertfordshire, United Kingdom
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Assessment of the eye irritation potential of chemicals: A comparison study between two test methods based on human 3D hemi-cornea models. Toxicol In Vitro 2015; 30:561-8. [PMID: 26362509 DOI: 10.1016/j.tiv.2015.09.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 09/02/2015] [Accepted: 09/06/2015] [Indexed: 11/21/2022]
Abstract
We have recently developed two hemi-cornea models (Bartok et al., Toxicol in Vitro 29, 72, 2015; Zorn-Kruppa et al. PLoS One 9, e114181, 2014), which allow the correct prediction of eye irritation potential of chemicals according to the United Nations globally harmonized system of classification and labeling of chemicals (UN GHS). Both models comprise a multilayered epithelium and a stroma with embedded keratocytes in a collagenous matrix. These two models were compared, using a set of fourteen test chemicals. Their effects after 10 and 60 minutes (min) exposure were assessed from the quantification of cell viability using the MTT reduction assay. The first approach separately quantifies the damage inflicted to the epithelium and the stroma. The second approach quantifies the depth of injury by recording cell death as a function of depth. The classification obtained by the two models was compared to the Draize rabbit eye test and an ex vivo model using rabbit cornea (Jester et al. Toxicol in Vitro. 24, 597-604, 2010). With a 60 min exposure, both of our models are able to clearly differentiate UN GHS Category 1 and UN GHS Category 2 test chemicals.
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Bhasker S, Kislay R, Rupinder KK, Jagat KR. Evaluation of nanoformulated therapeutics in an ex-vivo bovine corneal irritation model. Toxicol In Vitro 2015; 29:917-25. [DOI: 10.1016/j.tiv.2015.01.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 11/25/2014] [Accepted: 01/18/2015] [Indexed: 01/08/2023]
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Abdelkader H, Pierscionek B, Carew M, Wu Z, Alany RG. Critical appraisal of alternative irritation models: three decades of testing ophthalmic pharmaceuticals. Br Med Bull 2015; 113:59-71. [PMID: 25686845 DOI: 10.1093/bmb/ldv002] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Testing ocular tolerability of ocular pharmaceuticals is an essential regulatory requirement. The current approved reference model (gold standard) for ocular irritation testing is the Draize test. However this method is subjective and involves using live animals, hence the need to develop alternative in vitro and ex vivo testing strategies. SOURCE OF DATA Pubmed, Science Direct, Scopus, Google Scholar, Medline, Current Content, Web of Science and validation reports from international regulatory bodies; The Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM) and European Centre for the Validation of Alternative Methods (ECVAM) were searched for in vitro alternatives. AREA OF AGREEMENT Whilst no single in vitro test can effectively replace the Draize eye irritation test, regulatory bodies and cosmetic/pharmaceutical industries agree that there is a need for in vitro alternatives with validated endpoints to evaluate pharmaceutical ingredients and finished eye products. AREA OF CONTROVERSY There is no single in vitro test / assay that can predict the ocular irritation potential of mild to moderate test substances. AREA TIMELY FOR DEVELOPING RESEARCH This review provides a critical appraisal of the selected in vitro and ex vivo ocular toxicity models recommended by international regulatory bodies. These include cytotoxicity methods, biochemical systems and ex vivo assays. The latter are approved by ECVAM as in vitro alternatives for the well-known Draize test. Hen's egg test-chorioallantoic membrane and the isolated rabbit eye test are also accepted by regulatory agencies in France, Germany, the Netherlands and the UK. A combination of ex vivo assays along with histological examination of excised bovine cornea can predict the conjunctival and corneal tolerability and cover a wider range of ocular pharmaceutical substances.
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Affiliation(s)
- Hamdy Abdelkader
- Faculty of Science, Engineering and Computing, Kingston University London, Kingston upon Thames, UK Department of Pharmaceutics, Faculty of Pharmacy, Minia University, Minia, Egypt
| | - Barbara Pierscionek
- Faculty of Science, Engineering and Computing, Kingston University London, Kingston upon Thames, UK
| | - Mark Carew
- Faculty of Science, Engineering and Computing, Kingston University London, Kingston upon Thames, UK
| | - Zimei Wu
- School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Raid G Alany
- Faculty of Science, Engineering and Computing, Kingston University London, Kingston upon Thames, UK School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
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25
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Wilson SL, Ahearne M, Hopkinson A. An overview of current techniques for ocular toxicity testing. Toxicology 2015; 327:32-46. [DOI: 10.1016/j.tox.2014.11.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 11/05/2014] [Accepted: 11/06/2014] [Indexed: 12/25/2022]
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Keeping an eye on decellularized corneas: a review of methods, characterization and applications. J Funct Biomater 2013; 4:114-61. [PMID: 24956084 PMCID: PMC4030906 DOI: 10.3390/jfb4030114] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 05/08/2013] [Accepted: 05/28/2013] [Indexed: 12/13/2022] Open
Abstract
The worldwide limited availability of suitable corneal donor tissue has led to the development of alternatives, including keratoprostheses (Kpros) and tissue engineered (TE) constructs. Despite advances in bioscaffold design, there is yet to be a corneal equivalent that effectively mimics both the native tissue ultrastructure and biomechanical properties. Human decellularized corneas (DCs) could offer a safe, sustainable source of corneal tissue, increasing the donor pool and potentially reducing the risk of immune rejection after corneal graft surgery. Appropriate, human-specific, decellularization techniques and high-resolution, non-destructive analysis systems are required to ensure reproducible outputs can be achieved. If robust treatment and characterization processes can be developed, DCs could offer a supplement to the donor corneal pool, alongside superior cell culture systems for pharmacology, toxicology and drug discovery studies.
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Dholakiya SL, Barile FA. Alternative methods for ocular toxicology testing: validation, applications and troubleshooting. Expert Opin Drug Metab Toxicol 2013; 9:699-712. [DOI: 10.1517/17425255.2013.783013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Abstract
There has been relatively little progress regarding the acceptance of in vitro tests by regulatory authorities since the second Practical In Vitro Toxicology Conference in 1989. Advances have been made in the international acceptance of the use of in vitro methods to identify compounds with mutagenic potential. The recognition, in international guidelines on skin and eye irritancy studies, of the need for a hierarchical approach, including the use of in vitro methods to screen out severe irritants, has also been welcome. The reasons for the relatively slow progress are considered. In the case of repeated-dose animal toxicity studies, these represent an effective broad-spectrum approach to identifying the general toxic effects and target organs. It will be difficult to design in vitro methods capable of mirroring the complex interactions seen in the whole animal or the multitudes of potential targets for toxic effects. In vitro studies may, however, be valuable in characterizing such effects once identified from the animal studies. Similar considerations apply to teratogenicity, where possible mechanisms include disturbances in placental function or in maternal metabolism. These examples illustrate the fairly substantial scientific obstacles that exist in some areas. The relatively rapid acceptance of mutagenicity studies was, to some extent, due to their single, underlying mechanism, namely, damage to DNA. In view of these problems, effort has concentrated on local effects such as skin and eye irritancy. Even here, the in vivo response is a complex series of reactions, and there is the assumption that a battery of in vitro tests will be needed. There have been difficulties in identifying the most promising combination of tests to subject to detailed validation. In addition, the number and identity of the 'reference' chemicals to be used and the comparative data (in vivo animal data or human data) needed has proved to be a matter of much debate. In addition to these difficulties, the need for international acceptance of the validation data has necessitated the adoption of a more international perspective. However, a large international study is now underway which, it is hoped, will lead to some real progress in the eye irritancy area.
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Affiliation(s)
- R J Fielder
- Department of Health, HEF(M) Division, London, UK
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Abstract
Human and rabbit isolated eyes were compared, not in order to propose yet another test, but to explore the boundaries of the rabbit isolated cornea as a model for primary damage to human cornea. Changes in corneal thickness and in epithelial morphology were followed on recovery from cold-induced oedema and after exposure to the test chemicals. There was no statistical difference between control human and rabbit eyes in recovery from severe oedema. The effects of exposure to allyl alcohol, Arlagard E, NaOH (1 N), NaCl, sodium lauryl sulphate (2%) and Tween-20 were similar in human and rabbit eyes. Acetone, ethanol and glycerol had opposed-sign effects on corneal thickness in human and rabbit. From the small number of substances tested it can be concluded qualitatively that stored rabbit eyes behave in a manner similar to freshly isolated rabbit eyes, and that substances in which penetration depends on surface properties of the cornea may have species-specific effects.
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Affiliation(s)
- M Berry
- University of Bristol, Department of Ophthalmology, Bristol Eye Hospital, Lower Maudlin Street, Bristol BS1 2LX, UK
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30
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Barile FA. Validating and troubleshooting ocular in vitro toxicology tests. J Pharmacol Toxicol Methods 2010; 61:136-45. [PMID: 20096797 DOI: 10.1016/j.vascn.2010.01.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 01/12/2010] [Accepted: 01/14/2010] [Indexed: 11/25/2022]
Abstract
In vitro organotypic models for testing ocular irritants have warranted sufficient interest as methods to replace in vivo ocular testing. The in vitro organotypic models claim to maintain short-term normal physiological and biochemical functions of the mammalian cornea in an isolated system. In these test methods, damage by the test substance is assessed by quantitative measurements of changes in corneal opacity and permeability using opacitometry and spectrophotometry, respectively. Both measurements are used quantitatively for irritancy classification for prediction of the in vivo ocular irritation potential of a test substance. Examples of organotypic models that incorporate these criteria include: the bovine corneal opacity and permeability (BCOP) assay, the isolated chicken eye (ICE) test method and the isolated rabbit eye (IRE) assay. A fourth method, the hen's egg test-chorioallantoic membrane (HET-CAM) assay, differs in the evaluation criteria but is also normally included among this class of in vitro protocols. Each of these protocols is discussed in detail as representative candidate in vitro methods for assessing ocular irritation and corrosion. The methodologies, protocol details, applications, and their validation status are discussed. A brief historical perspective of the development of original in vitro ocular testing models is also mentioned. More importantly, improving and troubleshooting the current techniques, in order to present the models as stand-alone in vitro tools for ocular toxicity assessment, is emphasized.
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Affiliation(s)
- Frank A Barile
- Department of Pharmaceutical Sciences, Toxicology Division, St. John's University, College of Pharmacy and Allied Health Professions, Queens, New York 11439, USA.
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Kusano M, Uematsu M, Kumagami T, Sasaki H, Kitaoka T. Evaluation of Acute Corneal Barrier Change Induced by Topically Applied Preservatives Using Corneal Transepithelial Electric Resistance In Vivo. Cornea 2010; 29:80-5. [DOI: 10.1097/ico.0b013e3181a3c3e6] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Schutte K, Prinsen M, McNamee P, Roggeband R. The isolated chicken eye test as a suitable in vitro method for determining the eye irritation potential of household cleaning products. Regul Toxicol Pharmacol 2009; 54:272-81. [DOI: 10.1016/j.yrtph.2009.05.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 03/27/2009] [Accepted: 05/11/2009] [Indexed: 10/20/2022]
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Marinovich M, Tragni E, Corsini A, Galli CL. Quantification ofIn VitroCytotoxicity of Surfactants: Correlation with their Eye Irritation Potential. ACTA ACUST UNITED AC 2008. [DOI: 10.3109/15569529009036323] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Keith AB, Tito MC, Demetruuas J, Driedger A, John FG, Gregory TG, Kong B, McCormick WC, North-Root H, Michael GR, Richard IS. In vitro methods for estimating eye irritancy of cleaning products phase i: preliminary assessment. ACTA ACUST UNITED AC 2008. [DOI: 10.3109/15569528809052327] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Nardone RM, Bradlaw JA. Toxicity Testing with in Vitro Systems: I. Ocular Tissue Culture. ACTA ACUST UNITED AC 2008. [DOI: 10.3109/15569528309065306] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Roland M. Nardone
- Department of Biology and The Center for Advanced Training in Cell and Molecular Biology, The Catholic University of America, Washington, DC
| | - June A. Bradlaw
- Division of Toxicology Food and Drug Administration Washington, DC
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Whittle E, Basketter D, York M, Kelly L, Hall T, McCall J, Botham P, Esdaile D, Gardner J. Findings of an Interlaboratory Trial of the Enucleated Eye Method as an Alternative Eye Irritation Test. ACTA ACUST UNITED AC 2008. [DOI: 10.3109/15376519209064803] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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38
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Seifried HE. Eye Irritation Testing: Historical Perspectives and Future Directions†. ACTA ACUST UNITED AC 2008. [DOI: 10.3109/15569528609036294] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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39
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Castro-Muñozledo F. Corneal epithelial cell cultures as a tool for research, drug screening and testing. Exp Eye Res 2007; 86:459-69. [PMID: 18191836 DOI: 10.1016/j.exer.2007.11.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Revised: 11/27/2007] [Accepted: 11/28/2007] [Indexed: 11/29/2022]
Abstract
Understanding of visual system function and the development of new therapies for corneal diseases and damages depend upon comprehension of the biological roles of the tissue. The in vitro cultivation of corneal epithelial cells and cell lines derived from them has become a powerful tool to analyze and understand such issues. Currently, researchers have developed well-defined and precisely described culture protocols and a collection of corneal epithelial cell lines. These cell lines have been obtained through different experimental approaches: (1) the ectopic expression of oncogenes, (2) the inactivation of p16 and p53 pathways and hTERT expression, and (3) the spontaneous establishment after serial cultivation of cells. The advantages or disadvantages for these approaches are discussed. In conclusion, the availability of several culture protocols and immortalized cell lines that express corneal epithelial phenotype will be useful for investigating issues such as gene regulation and tissue development, or for validating alternative methods in toxicology.
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Affiliation(s)
- Federico Castro-Muñozledo
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del IPN, México City, Mexico.
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40
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Uematsu M, Kumagami T, Kusano M, Yamada K, Mishima K, Fujimura K, Sasaki H, Kitaoka T. Acute corneal epithelial change after instillation of benzalkonium chloride evaluated using a newly developed in vivo corneal transepithelial electric resistance measurement method. Ophthalmic Res 2007; 39:308-14. [PMID: 17957130 DOI: 10.1159/000109986] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2006] [Accepted: 01/29/2007] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Acute corneal permeability change after instillation of benzalkonium chloride (BAC) was evaluated using a newly developed in vivo corneal transepithelial electric resistance (TER) measurement method. METHOD Corneal TER was measured by Ag/AgCl electrodes placed in the anterior aqueous chamber and on the cornea of live rabbit eyes. TER was measured and TER change after instillation of 0.05% BAC solution was monitored. After TER measurement, cornea was excised and fixed for transmission and scanning electron microscopy. For the control study, physiologic saline was used instead of BAC. RESULTS The TER of normal rabbit cornea was 602.3 +/- 195.0 Omega cm(2). TER decreased instantly after instillation of 0.05% BAC. In 5 s, TER decreased to 58.3 +/- 5.2%. In 60 s, TER decreased to 18.5 +/- 3.2%. At all time points, TER after instillation of 0.05% BAC was significantly lower than that of the control (p < 0.0001). Dissociation of tight junctions and the destruction of superficial cell membranes were observed under electron microscopy. CONCLUSION Corneal epithelial change with increased permeability is rapid and intense after the instillation of highly concentrated BAC solution, accompanied by disorder of tight junctions and cell membranes of superficial cells. The newly developed in vivo corneal TER measurement method is suitable for assessing acute corneal change after drug instillation.
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Affiliation(s)
- Masafumi Uematsu
- Department of Ophthalmology and Visual Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
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41
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Ubels JL, Clousing DP. In vitro alternatives to the use of animals in ocular toxicology testing. Ocul Surf 2007; 3:126-42. [PMID: 17131018 DOI: 10.1016/s1542-0124(12)70195-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Chemical substances, including household products, industrial chemicals, and cosmetics, must be tested for ocular toxicity or irritancy so that the public can be assured of their safety or warned of dangers associated with their use. The in vivo Draize test is the standard method used to meet this requirement; however, this test is coming under increasing criticism on scientific and ethical grounds. This has led to the development of a large number of proposed in vitro tests, some of which are routinely used to screen chemicals in toxicology laboratories. This review addresses regulations governing ocular irritancy testing and the current status of the movement toward use of alternative methods. Such methods include the use of cultured cells, hen's eggs, isolated animal eyes and corneas, human corneal epithelial cell lines, and the recently developed in vitro corneal equivalent models. The protocols for these methods are outlined, and their endpoints are described with respect to prediction of in vivo responses. The tests are evaluated in the context of the outcomes of validation studies and acceptance by regulatory agencies. While several of these tests yield useful information concerning ocular irritancy, to date, no in vitro alternative test has been validated as a replacement for the Draize test. If the goal of replacing the in vivo test while protecting the public from chemical eye injury is to be achieved, further development and improvement of alternative tests, as well as establishment of a human ocular toxicity data base, are required.
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Affiliation(s)
- John L Ubels
- Department of Biology, Calvin College, Grand Rapids, MI 49546, USA.
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42
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Abstract
PURPOSE OF REVIEW Superficial ocular tissues are frequently exposed to damage produced by chemical compounds applied on or around the ocular surface for cosmetic, therapeutic or accidental reasons. An experimental test measuring objectively and in a reproducible way any potential damaging effect would certainly help in prospectively minimizing unwanted effects. The Draize eye test, although commonly employed to date, does not seem to be quite satisfactory in this respect. RECENT FINDINGS The limits of the Draize eye test and the results of some modified versions of the test are analysed. In particular, the good predictivity of the so-called low-volume Draize eye test and the recent findings of studies on the in-vitro and ex-vivo alternatives to the Draize eye test are presented. SUMMARY The Draize eye test, despite criticisms, has been used in the clinical setting for a long time and still remains the reference protocol. To date, only a combination of alternative methods, none of which is devoid of serious criticisms, seems to be able to exhaustively recognize potential irritants and avoiding for that purpose, in some cases, the use of living animals.
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Chetoni P, Burgalassi S, Monti D, Saettone MF. Ocular toxicity of some corneal penetration enhancers evaluated by electrophysiology measurements on isolated rabbit corneas. Toxicol In Vitro 2003; 17:497-504. [PMID: 12849734 DOI: 10.1016/s0887-2333(03)00052-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The influence on electrical resistance and membrane potential of rabbit corneas in vitro of some chemicals used as adjuvants in ophthalmic formulations was investigated, in the attempt to correlate changes in electrophysiological properties of the corneal tissue (possibly indicative of toxic/damaging effects to the corneal epithelium), with the promoting effect of the substances on transcorneal permeation in vitro of timolol maleate (TM). The chemicals, tested at different concentrations, were benzalkonium chloride (BAC), sodium ethylenediaminetetraacetate (EDTA), polyoxyethylene-20-stearyl ether (PSE), polyethoxylated castor oil (PCO), deoxycholic acid sodium salt (DC) and cetylpyridinium chloride (CPC). For these substances, definite correlations were found between promoting activity for permeation of TM and modification of electrophysiological parameters. These parameters were in all cases significantly altered by all agents at all concentrations after a 5-h contact. However, after a 1-h contact, 0.001% PSE and CPC did not significantly modify the corneal resistance, while PCO and PSE did not significantly modify the transcorneal potential at the tested concentrations. Only 0.001% PSE, a nonionic surfactant used as solubilizer and emulsifier, active as promoter for TM, did not modify both electrophysiological parameters to a significant extent after 1 h. The results of this study indicate correlations between ocular toxicity, promoting activity for transcorneal permeation of timolol and modification of the electrophysiological parameters.
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Affiliation(s)
- P Chetoni
- Department of Bioorganic Chemistry and Biopharmaceutics, University of Pisa, 33 I-56126, Italy.
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44
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Abstract
Ocular irritation testing has been one of the animal test methods most criticised by animal welfare advocates. Additional criticism has arisen from within the scientific community, based on the variability of the animal test results and the questionable relevance of the extremely high dose levels employed. As a result, the Draize eye irritation test has been one of the main targets for in vitro replacement. Despite extensive efforts, however, there is still no in vitro method that is fully validated as a regulatory replacement. In spite of this, many individual companies are using diverse in vitro ocular irritation tests to gain important safety and efficacy information about their products and raw materials, eliminating the need for animal testing in the process. This is done in a safe fashion by applying intelligent testing paradigms. ECVAM has played a major role in this success, through its many programmes that have emphasised the importance of understanding the true toxicological need, and then using in vitro tests to provide that information. Thus, even in the absence of a successfully validated regulatory assay, the desired result of reducing animal testing is being met.
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Affiliation(s)
- Rodger D Curren
- Institute for In Vitro Sciences, Inc., Suite 220, 21 Firstfield Road, Gaithersburg, MD 20878, USA
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45
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Abstract
The conventional method for assessing the safety of products, ranging from pharmaceuticals to agrochemicals, biocides and industrial and household chemicals - including cosmetics - involves determining their toxicological properties by using experimental animals. The aim is to identify any possible adverse effects in humans by using these animal models. Providing safe products is undoubtedly of the utmost importance but, over the last decade or so, this aim has come into conflict with strong public opinion, especially in Europe, against animal testing. Industry, academia and the regulators have worked in partnership to find other ways of evaluating the safety of products, by non-animal testing, or at least by reducing the numbers of animals required and the severity of the tests in which they are used. There is a long way to go before products can be evaluated without any animal studies, and it may be that this laudable aim is an impossible dream. Nevertheless, considerable progress has been made by using a combination of in vitro tests and the prediction of properties based on chemical structure. The aim of this review is to describe these important and worthwhile developments in various areas of toxicological testing, with a focus on the European regulatory framework for general industrial and household chemicals.
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46
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Jones PA, Budynsky E, Cooper KJ, Decker D, Griffiths HA, Fentem JH. Comparative evaluation of five in vitro tests for assessing the eye irritation potential of hair-care products. Altern Lab Anim 2001; 29:669-92. [PMID: 11709042 DOI: 10.1177/026119290102900606] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This study compared five methods, the isolated rabbit eye (IRE), bovine corneal opacity and permeability (BCOP), EpiOcular, fluorescein leakage (FL) and neutral red release (NRR) assays, for predicting the eye irritation potential of hair-care formulations. Ten shampoo and seven conditioner formulations of known ocular irritation potential were tested. Each group included a market-acceptable formulation as a comparative benchmark. Predictions of ocular irritation were made by using classification models (IRE, BCOP and EpiOcular assays) or by direct comparison with benchmarks (IRE, EpiOcular, FL and NRR assays). The BCOP assay was less sensitive than the IRE test in discriminating between formulations of different irritation potentials, and did not perform as well as the other assays in identifying mild formulations. All of the assays appeared to be better at discriminating correctly between the shampoos than between the conditioners. The EpiOcular assay showed the closest concordance between the in vivo results and the in vitro data from cell-based assays (particularly for shampoos). The FL assay also showed a high concordance (particularly for conditioners). There was a tendency for these in vitro assays to over-predict eye irritation potential, but there was no under-prediction and they were particularly successful at identifying mild formulations. The NRR assay was less predictive with both shampoos and conditioners. The results from this comparative evaluation fully support the continued use of the IRE test as a suitable alternative to in vivo eye irritation testing in rabbits, although it also over-predicted the irritancies of several of the formulations. The value of using concurrent benchmarks (reference standards), appropriate to the materials being tested, in interpreting the data obtained from in vitro tests, was also demonstrated. Overall, the results indicate that further comparisons of the IRE, EpiOcular and FL assays are warranted using much larger numbers of test materials.
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Affiliation(s)
- P A Jones
- Safety & Environmental Assurance Centre (SEAC), Unilever Colworth Laboratory, Sharnbrook, Bedfordshire MK44 1LQ, UK
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Cooper KJ, Earl LK, Harbell J, Raabe H. Prediction of ocular irritancy of prototype shampoo formulations by the isolated rabbit eye (IRE) test and bovine corneal opacity and permeability (BCOP) assay. Toxicol In Vitro 2001; 15:95-103. [PMID: 11287169 DOI: 10.1016/s0887-2333(00)00060-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The isolated rabbit eye (IRE) test and bovine corneal opacity and permeability (BCOP) assay were evaluated for their ability to predict the eye irritation potential of a range of hair shampoo formulations, some containing a novel non-surfactant ingredient known to be an ocular irritant. The additional endpoints of corneal swelling and histological examination were incorporated into the standard BCOP protocol. Historic Draize data were available for several of the formulations and served as a reference. The standard BCOP assay (without histology) failed to distinguish between shampoos of low and high irritant potential, when exposure times of 10 and 60 min were employed (for undiluted and 10% dilution of the shampoos, respectively) and the in vitro score classified the majority of formulations as mild. The incorporation of the histological endpoint to the BCOP protocol allowed discrimination between formulations of differing irritancy, and should be included to augment the standard BCOP protocol. Corneal swelling values did not, however, correlate with the irritant potential of the shampoos tested. The IRE which includes the endpoints of corneal swelling and histopathological scoring produced classifications of irritancy that were fairly consistent with in vivo data and distinguished between the high and low irritant potential shampoos.
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Affiliation(s)
- K J Cooper
- Safety and Environment Assurance Centre, Toxicology Unit, Unilever Research, Colworth House, Sharnbrook, MK44 1LQ, Bedfordshire, UK.
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Kurishita A, Katoh T, Ohsawa H, Nakasawa H, Sugiura H, Usami M, Kakishima H, Kuwahara H, Ohuchi J, Kasai Y, Ohokoshi K, Okamoto Y, Morito Y, Shibata M, Tsuda T, Kojima H, Mizutani A, Ikeda N, Sumida Y, Nishifuji M, Katagiri M, Kazama A, Hayashi N, Hirose A, Kaneko T, Ohno Y. Interlaboratory validation of the in vitro eye irritation tests for cosmetic ingredients. (5) Skin2TM ZK1100 and tissue equivalent assay. Toxicol In Vitro 1999; 13:139-51. [DOI: 10.1016/s0887-2333(98)00068-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/1998] [Indexed: 11/25/2022]
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The Neutral Red Uptake Assay: Comments on the Results of the Istituto Superiore di Sanità in the EC/HO Validation Study. Altern Lab Anim 1998. [DOI: 10.1177/026119299802600110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The neutral red uptake (NRU) assay was included, among others, in a validation study sponsored by the European Commission/British Home Office (EC/HO) study, for its reliability as an in vitro alternative to the Draize eye irritancy test. The test was performed in parallel by four laboratories (Istituto Superiore di Sanità [ISS], Microbiological Associates, Hatano Research Institute and Kurabo Industries) on 60 selected chemicals. The results obtained by the ISS are reported in this paper. A poor rank correlation was obtained between the in vivo endpoint and the ISS in vitro results for the full set of chemicals and for the subsets, with the exception of surfactants, by an independent statistics group. The same unsatisfactory results were obtained by the ISS group when the rank correlation was calculated for compounds divided into chemical groups. The performance of the NRU assay, as an alternative to the Draize eye irritancy test, is discussed.
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Doughty M. Evaluation of short-term bovine eye storage protocol for the enucleated eye toxicity test. Toxicol In Vitro 1997; 11:229-40. [DOI: 10.1016/s0887-2333(97)00011-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/24/1997] [Indexed: 11/28/2022]
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