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Brandmair K, Dising D, Finkelmeier D, Schepky A, Kuehnl J, Ebmeyer J, Burger-Kentischer A. A novel three-dimensional Nrf2 reporter epidermis model for skin sensitization assessment. Toxicology 2024; 503:153743. [PMID: 38341018 DOI: 10.1016/j.tox.2024.153743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 01/25/2024] [Accepted: 02/06/2024] [Indexed: 02/12/2024]
Abstract
Skin sensitization assessment has progressed from the use of animal models towards the application of New Approach Methodologies (NAMs). Several skin sensitization NAMs are accepted for regulatory use, but a majority relies on submerged in vitro cell cultures that limit their applicability domain, posing challenges for testing hydrophobic chemicals and mixtures. A newly developed three-dimensional (3D) Nrf2 reporter epidermis model for skin sensitization assessment is reported. This NAM may help to overcome these limitations. The NAM combines the in vivo-like biology and exposure conditions of 3D epidermis models with the reliability, convenience, and cost-effectiveness of secreted reporter gene technology. The Keap1-Nrf2-ARE pathway was chosen as the reporter gene read-out, as it is induced by most skin sensitizers and already adopted in OECD Test guideline 442D. Immortalized human primary keratinocytes (Ker-CT) were stably transfected with the pIGB-Nrf2-SEAP vector to construct a Nrf2 reporter cell line. Ker-CT Nrf2 reporter cells showed negligible basal expression of the Secreted Embryonic Alkaline Phosphatase (SEAP) reporter, which was induced 13.5-fold by exposure to the skin sensitizer cinnamic aldehyde (CA). Co-exposure to CA and the Nrf2 inhibitor glucocorticoid clobetasol propionate significantly suppressed the CA-induced SEAP expression, confirming dependance of the SEAP expression on Nrf2 activation. Using air-liquid interface and animal constituent free culture conditions, the Ker-CT Nrf2 reporter cells differentiated to stratified 3D epidermis models with an in vivo-like skin architecture and functional skin barrier. Evaluation of a Ker-CT Nrf2 reporter cell-based 2D assay by testing 10 conventional reference chemicals showed a predictive accuracy for skin sensitization potential of 80% and 70% compared to LLNA and human data in two independent laboratories and a high intra- and interlaboratory reproducibility. Moreover, the 3D epidermis models predicted 3 sensitizing and 2 non-sensitizing reference chemicals correctly in a first proof-of-concept study. Further investigations foresee the testing of additional chemicals, including hydrophobic compounds and mixtures to confirm the potential of the 3D epidermis models to broaden the applicability domain for NAM-based skin sensitization assessment.
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Affiliation(s)
- K Brandmair
- Beiersdorf AG, Beiersdorfstraße 1-9, Hamburg 20245, Germany
| | - D Dising
- Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Cell and Tissue Technologies, Nobelstraße 12, Stuttgart 70569, Germany
| | - D Finkelmeier
- Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Cell and Tissue Technologies, Nobelstraße 12, Stuttgart 70569, Germany
| | - A Schepky
- Beiersdorf AG, Beiersdorfstraße 1-9, Hamburg 20245, Germany
| | - J Kuehnl
- Beiersdorf AG, Beiersdorfstraße 1-9, Hamburg 20245, Germany
| | - J Ebmeyer
- Beiersdorf AG, Beiersdorfstraße 1-9, Hamburg 20245, Germany.
| | - A Burger-Kentischer
- Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Cell and Tissue Technologies, Nobelstraße 12, Stuttgart 70569, Germany.
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Pierzchalski A, Zenclussen AC, Herberth G. A comprehensive battery of flow cytometric immunoassays for the in vitro testing of chemical effects in human blood cells. Front Immunol 2024; 14:1327960. [PMID: 38229911 PMCID: PMC10790304 DOI: 10.3389/fimmu.2023.1327960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 12/05/2023] [Indexed: 01/18/2024] Open
Abstract
Background There is a growing need for immunological assays to test toxic and modulatory effects of chemicals. The assays should be easy to use, reproducible and superior to cell line-based assays. We have therefore developed a comprehensive portfolio of assays based on primary human blood cells that are suitable for testing chemical effects. Methods The flow cytometry-based assays were designed to target a wide range of human peripheral blood mononuclear cells and whole blood, including T cells, NK cells, B cells, basophils and innate-like T cells such as γδT, MAIT and NKT cells. We have selected a set of activation markers for each immune cell, e.g: CD154 (T cells), CD137, CD107a (NK cells), CD63 (basophils), CD69, CD83 (B cells), CD69, IFN-γ (MAIT cells) and we selected cell specific stimuli: aCD3 antibodies (T cells); E. coli and cytokines IL-12/15/18 (MAIT cells); CpG ODN2006, R848 or aCD40 antibodies (B cells), fMLP or aFcϵR1 (basophils) or K562 cells (NK cells). Results By selecting immune cell-specific markers and cell-specific stimuli, we were able to induce particular immune responses from the targeted immune cells. For example, the response to stimulation with anti-CD3 antibodies was in 36.8% of CD107a+CD8+ cells. Cytokine stimulation induced the production of IFN-γ in 30% of MAIT cells. After stimulation with E. coli, around 50% of MAIT cells produced TNF. About 40% of basophils responded to aFcƐR1 stimulation. Similar activation ranges were achieved in K562-stimulated NK cells. Conclusion Our test portfolio covers the most relevant immune cells present in human blood, providing a solid basis for in vitro toxicity and immunomodulatory testing of chemicals. By using human blood, the natural composition of cells found in the blood can be determined and the effects of chemicals can be detected at the cellular level.
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Affiliation(s)
- Arkadiusz Pierzchalski
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Immunology, Leipzig, Germany
| | - Ana C. Zenclussen
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Immunology, Leipzig, Germany
- Perinatal Immunology Research Group, Medical Faculty, Saxonian Incubator for Clinical Translation (SIKT), University of Leipzig, Leipzig, Germany
| | - Gunda Herberth
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Immunology, Leipzig, Germany
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de Ávila RI, Aleksic M, Zhu B, Li J, Pendlington R, Valadares MC. Non-animal approaches for photoallergenicity safety assessment: Needs and perspectives for the toxicology for the 21st century. Regul Toxicol Pharmacol 2023; 145:105499. [PMID: 37805107 DOI: 10.1016/j.yrtph.2023.105499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 09/07/2023] [Accepted: 09/28/2023] [Indexed: 10/09/2023]
Abstract
Certain chemicals and/or their byproducts are photoactivated by UV/VIS and trigger a dermal allergenic response, clinically recognized as photoallergic contact dermatitis (PACD). It is important to identify the chemicals which are potentially photoallergenic, not only for establishing the correct differential diagnosis between PACD and other photodermatoses, but also as causative agents which should be avoided as a preventative measure. Moreover, materials with photoallergenic properties need to be correctly identified to allow thorough safety assessments for their use in finished products (e.g. cosmetics). Development of methods for predicting photoallergenicity potential of chemicals has advanced at slow pace in recent years. To date, there are no validated methods for photosensitisation potential of chemicals for regulatory purposes, although it remains a required endpoint in some regions. The purpose of this review is to explore the mechanisms potentially involved in the photosensitisation process and discuss the methods available in the literature for identification of photosensitisers. The review also explores the possibilities of further research investment required to develop human-relevant new approach methodologies (NAMs) and next generation risk assessment (NGRA) approaches, considering the current perspectives and needs of the Toxicology for the 21st Century.
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Affiliation(s)
- Renato Ivan de Ávila
- Unilever Safety and Environmental Assurance Centre (SEAC), Colworth Science Park, Sharnbrook, Bedfordshire, UK; Laboratory of Education and Research in in Vitro Toxicology (Tox in), Faculty of Pharmacy, Universidade Federal de Goiás, Goiânia, GO, Brazil.
| | - Maja Aleksic
- Unilever Safety and Environmental Assurance Centre (SEAC), Colworth Science Park, Sharnbrook, Bedfordshire, UK
| | - Bin Zhu
- Unilever Research and Development Centre, Shanghai, China
| | - Jin Li
- Unilever Safety and Environmental Assurance Centre (SEAC), Colworth Science Park, Sharnbrook, Bedfordshire, UK
| | - Ruth Pendlington
- Unilever Safety and Environmental Assurance Centre (SEAC), Colworth Science Park, Sharnbrook, Bedfordshire, UK
| | - Marize Campos Valadares
- Laboratory of Education and Research in in Vitro Toxicology (Tox in), Faculty of Pharmacy, Universidade Federal de Goiás, Goiânia, GO, Brazil
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Gautier F, Assaf Vandecasteele H, Tourneix F, van Vliet E, Alépée N, Bury D. Skin sensitisation prediction using read-across, an illustrative next generation risk assessment (NGRA) case study for vanillin. Regul Toxicol Pharmacol 2023; 143:105458. [PMID: 37453556 DOI: 10.1016/j.yrtph.2023.105458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 07/11/2023] [Accepted: 07/13/2023] [Indexed: 07/18/2023]
Abstract
Skin sensitisation is a key adverse human health effect to be addressed in the safety assessment of cosmetic ingredients. Regulatory demands and scientific progress have led to the development of a Next Generation Risk Assessment (NGRA) framework, relying on the use of New Approach Methodologies (NAM) Defined Approaches (DA) and read-across instead of generating animal data. This case study illustrates the application of read-across for the prediction of the skin sensitisation potential of vanillin at the hypothetical use concentration of 0.5% in a shower gel and face cream. A three-step process was applied to select the most suitable analogues based on their protein reactivity, structural characteristics, physicochemical properties, skin metabolism profile and availability of skin sensitisation data. The applied read-across approach predicted a weak skin sensitiser potential for vanillin corresponding with a Local Lymph Node Assay EC3 value of 10%. Based on this EC3 value a point of departure of 2500 μg/cm2 was derived, resulting in an acceptable exposure level (AEL) of 25 μg/cm2. Because the consumer exposure levels (CEL) for the face cream (13.5 μg/cm2) and shower gel (0.05 μg/cm2) scenarios were lower than the AEL, the NGRA concluded both uses as safe.
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Affiliation(s)
| | | | - Fleur Tourneix
- L'Oréal, Research & Innovation, Aulnay-Sous-Bois, France
| | - Erwin van Vliet
- Innovitox Consulting & Services, Regentenland 35, 3994TZ, Houten, the Netherlands
| | | | - Dagmar Bury
- L'Oréal, Research & Innovation, Clichy, France.
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Grimm H, Biller-Andorno N, Buch T, Dahlhoff M, Davies G, Cederroth CR, Maissen O, Lukas W, Passini E, Törnqvist E, Olsson IAS, Sandström J. Advancing the 3Rs: innovation, implementation, ethics and society. Front Vet Sci 2023; 10:1185706. [PMID: 37396988 PMCID: PMC10310538 DOI: 10.3389/fvets.2023.1185706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 05/12/2023] [Indexed: 07/04/2023] Open
Abstract
The 3Rs principle of replacing, reducing and refining the use of animals in science has been gaining widespread support in the international research community and appears in transnational legislation such as the European Directive 2010/63/EU, a number of national legislative frameworks like in Switzerland and the UK, and other rules and guidance in place in countries around the world. At the same time, progress in technical and biomedical research, along with the changing status of animals in many societies, challenges the view of the 3Rs principle as a sufficient and effective approach to the moral challenges set by animal use in research. Given this growing awareness of our moral responsibilities to animals, the aim of this paper is to address the question: Can the 3Rs, as a policy instrument for science and research, still guide the morally acceptable use of animals for scientific purposes, and if so, how? The fact that the increased availability of alternatives to animal models has not correlated inversely with a decrease in the number of animals used in research has led to public and political calls for more radical action. However, a focus on the simple measure of total animal numbers distracts from the need for a more nuanced understanding of how the 3Rs principle can have a genuine influence as a guiding instrument in research and testing. Hence, we focus on three core dimensions of the 3Rs in contemporary research: (1) What scientific innovations are needed to advance the goals of the 3Rs? (2) What can be done to facilitate the implementation of existing and new 3R methods? (3) Do the 3Rs still offer an adequate ethical framework given the increasing social awareness of animal needs and human moral responsibilities? By answering these questions, we will identify core perspectives in the debate over the advancement of the 3Rs.
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Affiliation(s)
- Herwig Grimm
- Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna, University of Vienna, Vienna, Austria
| | - Nikola Biller-Andorno
- Institute of Biomedical Ethics and History of Medicine, University of Zurich, Zurich, Switzerland
| | - Thorsten Buch
- Institute of Laboratory Animal Science, University of Zurich, Zurich, Switzerland
| | - Maik Dahlhoff
- Institute of in vivo and in vitro Models, Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Gail Davies
- Department of Geography, University of Exeter, Exeter, United Kingdom
| | | | - Otto Maissen
- Federal Food Safety and Veterinary Office, Animal Welfare Division, Bern, Switzerland
| | - Wilma Lukas
- Innosuisse - Swiss Innovation Agency, Bern, Switzerland
| | - Elisa Passini
- National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs), London, United Kingdom
| | - Elin Törnqvist
- Department of Animal Health and Antimicrobial Strategies, Swedish National Veterinary Institute (SVA), Uppsala, Sweden
- Institute of Environmental Medicine, Karolinska Institutet, Solna, Sweden
| | - I. Anna S. Olsson
- Laboratory Animal Science, i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
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Roberts DW, Kimber I, Basketter DA. Specificity of the local lymph node assay (LLNA) for skin sensitisation. Regul Toxicol Pharmacol 2023; 141:105402. [PMID: 37116738 DOI: 10.1016/j.yrtph.2023.105402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 04/13/2023] [Accepted: 04/25/2023] [Indexed: 04/30/2023]
Abstract
The local lymph node assay (LLNA) has provided a large dataset against which performance of non-animal approaches for prediction of skin sensitisation potential and potency can be assessed. However, a recent comparison of LLNA results with human data has argued that LLNA specificity is low, with many human non-sensitisers, particularly hydrophobic chemicals, being false positives. It has been suggested such putative false positives result from hydrophobic chemicals causing cytotoxicity, which induces irritancy, in turn driving non-specific lymphocyte proliferation. This paper finds that the apparent reduced specificity of the LLNA largely reflects differences in definitions of the boundaries between weak skin sensitisers and non-sensitisers. A small number of LLNA false positives may be due to lymphocyte proliferation without skin sensitisation, but most alleged 'false' positives are in fact very weak sensitisers predictable from structure-activity considerations. The evidence does not support the hypothesis for hydrophobicity-induced false positives. Moreover, the mechanistic basis is untenable. Sound LLNA data, appropriately interpreted, remain a good measure of sensitisation potency, applicable across a wide hydrophilicity-lipophilicity range. The standard data interpretation protocol enables detection of very low levels of sensitisation, irrespective of regulatory significance, but there is scope to interpret the data to give focus on regulatory significance.
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Affiliation(s)
- David W Roberts
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moore's University, Liverpool, L3 3AF, UK.
| | - Ian Kimber
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
| | - David A Basketter
- DABMEB Consultancy Ltd, Abbey View, Abbey St, Kingswood, Wotton-under-Edge, GL12 8RN, UK
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Basketter DA. Risk management of skin sensitisers: A commentary. Regul Toxicol Pharmacol 2023; 140:105384. [PMID: 37028500 DOI: 10.1016/j.yrtph.2023.105384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 03/10/2023] [Accepted: 03/25/2023] [Indexed: 04/09/2023]
Abstract
Historically, allergic contact dermatitis (ACD) to chemicals encouraged hazard identification improvements, more sophisticated risk assessment and implementation of regulatory strategies, including banning of specific sensitising substances. The validation process applied to hazard identification methods demonstrates their accuracy; their use to characterise sensitiser potency facilitates quantitative and transparent risk assessment. Diagnostic patch testing at dermatology clinics worldwide delivers feedback showing where risk assessment/management has been insufficient or did not target the exposure of concern, thereby facilitating improvements. When urgent action to protect human health was required, regulations limited/banned, specific skin sensitisers. This can be seen in practice with the fragrance industry, a known source of ACD, thus requiring risk management, usually restrictions to limit allergy induction, and very rarely specific bans on ingredients. Experience and development of more sophisticated tools, e.g. to assess aggregate exposure from multitude of consumer product types, has led to repeated adaptation of risk assessment and promulgation of updated fragrance use limits. Although targeted control may not always lead to rapid change in the overall clinical picture, it is preferable to a blanket undifferentiated regulatory control of all sensitisers, resulting in unwarranted restrictions for many uses of no health concern, with consequent substantial socio-economic impacts.
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Gądarowska D, Kalka J, Daniel-Wójcik A, Mrzyk I. Alternative Methods for Skin-Sensitization Assessment. Toxics 2022; 10:740. [PMID: 36548573 PMCID: PMC9783525 DOI: 10.3390/toxics10120740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 06/17/2023]
Abstract
Skin sensitization is a term used to refer to the regulatory hazard known as allergic contact dermatitis (ACD) in humans or contact hypersensitivity in rodents, an important health endpoint considered in chemical hazard and risk assessments. Information on skin sensitization potential is required in various regulatory frameworks, such as the Directive of the European Parliament and the Council on Registration, Evaluation and Authorization of Chemicals (REACH). The identification of skin-sensitizing chemicals previously required the use of animal testing, which is now being replaced by alternative methods. Alternative methods in the field of skin sensitization are based on the measurement or prediction of key events (KE), i.e., (i) the molecular triggering event, i.e., the covalent binding of electrophilic substances to nucleophilic centers in skin proteins; (ii) the activation of keratinocytes; (iii) the activation of dendritic cells; (iv) the proliferation of T cells. This review article focuses on the current state of knowledge regarding the methods corresponding to each of the key events in skin sensitization and considers the latest trends in the development and modification of these methods.
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Affiliation(s)
- Dominika Gądarowska
- The Faculty of Energy and Environmental Engineering, Silesian University of Technology, Konarskiego 18, 44-100 Gliwice, Poland
- Łukasiewicz Research Network—Institute of Industrial Organic Chemistry Branch Pszczyna, Doświadczalna 27, 43-200 Pszczyna, Poland
| | - Joanna Kalka
- The Faculty of Energy and Environmental Engineering, Silesian University of Technology, Konarskiego 18, 44-100 Gliwice, Poland
| | - Anna Daniel-Wójcik
- Łukasiewicz Research Network—Institute of Industrial Organic Chemistry Branch Pszczyna, Doświadczalna 27, 43-200 Pszczyna, Poland
| | - Inga Mrzyk
- Łukasiewicz Research Network—Institute of Industrial Organic Chemistry Branch Pszczyna, Doświadczalna 27, 43-200 Pszczyna, Poland
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Flaire E, Nachat-Kappes R, Laporte C, Harmand MF, Simon M, Poinsot C. Alternative in vitro models used in the main safety tests of cosmetic products and new challenges. Int J Cosmet Sci 2022; 44:604-613. [PMID: 35842748 DOI: 10.1111/ics.12803] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 07/15/2022] [Indexed: 11/28/2022]
Abstract
BACKGROUND Guided by ethical considerations and regulatory requirements such as the 7th Amendment to the European Cosmetics Directive N° 1223/2009, the cosmetic industry has developed and evaluated alternative test strategies such as in vitro assays, in silico approaches for toxicological endpoints and efficacy of cosmetic products and cosmetics ingredients. In consequence, the European Centre for the Validation of Alternative Methods (ECVAM) has proposed a list of validated cell-based in vitro models for predicting the safety and toxicity of cosmetic ingredients. These models have been demonstrated as valuable and effective tools to overcome the limitations of animal in vivo studies. For example, 3D human skin equivalent models are used to evaluate skin irritation potential; and excised human skin is used as the gold standard for the evaluation of dermal absorption. OBJECTIVE This review presents, in relation to the regulatory requirements, the main alternative in vitro models used in the safety tests of cosmetic products, focusing on skin sensitization, skin corrosion, skin irritation and skin absorption, with advantages and limitations of each model. Recent innovative 3D cell technologies such as Organ-on-a-Chip (OoC) models that can bring significant improvements for toxicology and efficacy testing are also presented. CONCLUSION The development of OoC technology is promising for assessing the toxicity of substances contained in cosmetics, particularly for repeated dose toxicity, for which no alternative in vitro methods are currently available. Nevertheless, aside from the challenges, the technology needs to be validated and accepted by regulatory organizations as an effective method. Collaboration between researchers, regulatory organizations and industry would be required to achieve this validation.
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Affiliation(s)
- Edith Flaire
- Groupe ICARE. Biopôle, Saint Beauzire.,UMR 1019 INRAE-University Clermont-Auvergne, UNH (Human Nutrition Unity), ECREIN Team, Clermont-Ferrand, France
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