The Experts below are selected from a list of 12570 Experts worldwide ranked by ideXlab platform
Hajime Kojima - One of the best experts on this subject based on the ideXlab platform.
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construction of three dimensional dermo epidermal Skin equivalents using cell coating technology and their utilization as alternative Skin for permeation studies and Skin Irritation tests
Tissue Engineering Part A, 2017Co-Authors: Takami Akagi, Hajime Kojima, Mayuka Nagura, Ayami Hiura, Mitsuru AkashiAbstract:In vitro generated human Skin equivalents are generating interest as promising tools in basic study, as alternatives to animal testing, and for clinical applications in regenerative medicine. For prediction of Skin Irritation and corrosion, three-dimensional human Skin equivalents consisting of differentiated human keratinocytes (KCs) have been developed and some models have been internationally accepted. However, more delicate assessments using full-thickness Skin models, such as Skin sensitization tests, cannot be performed due to the lack of a dermis containing fibroblasts or appendages. In a previous study, we developed dermo-epidermal human Skin equivalents (DESEs) using a cell coating technique, which employs cell surface coating by layer-by-layer assembled extracellular matrix (ECM) films. The DESEs with dermis consisting of normal human dermal fibroblasts (NHDFs) and epidermis consisting of human KCs were easily fabricated by using this technology. In this study, the constructed DESEs were evaluated as an alternative Skin for Skin permeation and Irritation tests. A good relationship of permeability coefficient of chemicals was observed between the DESEs and human Skin data. We investigated whether the DESEs, a new in vitro Skin model, are capable of identifying Skin irritant and nonirritant substances among 20 reference chemicals. It was confirmed that the DESEs are applicable to Skin Irritation testing as defined in the European Centre for the Validation of Alternative Methods (ECVAM) Performance Standard (OECD Test Guideline 439). We further studied the construction of DESEs with density-controlled blood capillary networks using human umbilical vein endothelial cells (HUVECs). The results suggest that DESEs allowing incorporation of Skin appendages are more promising alternatives to animal testing and can be applied to the design of physiologically relevant in vitro Skin models.
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construction of three dimensional dermo epidermal Skin equivalents using cell coating technology and their utilization as alternative Skin for permeation studies and Skin Irritation tests
Tissue Engineering Part A, 2017Co-Authors: Takami Akagi, Hajime Kojima, Mayuka Nagura, Ayami Hiura, Mitsuru AkashiAbstract:In vitro generated human Skin equivalents are generating interest as promising tools in basic study, as alternatives to animal testing, and for clinical applications in regenerative medicine. For prediction of Skin Irritation and corrosion, three-dimensional human Skin equivalents consisting of differentiated human keratinocytes (KCs) have been developed and some models have been internationally accepted. However, more delicate assessments using full-thickness Skin models, such as Skin sensitization tests, cannot be performed due to the lack of a dermis containing fibroblasts or appendages. In a previous study, we developed dermo–epidermal human Skin equivalents (DESEs) using a cell coating technique, which employs cell surface coating by layer-by-layer assembled extracellular matrix (ECM) films. The DESEs with dermis consisting of normal human dermal fibroblasts (NHDFs) and epidermis consisting of human KCs were easily fabricated by using this technology. In this study, the constructed DESEs were evaluat...
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a catch up validation study of an in vitro Skin Irritation test method using reconstructed human epidermis labcyte epi model24
Journal of Applied Toxicology, 2014Co-Authors: Hajime Kojima, Masakazu Katoh, Shinsuke Shinoda, Tamie Suzuki, Yoshihiro Yamaguchi, Saori Hagiwara, Runa Izumi, Maki Nakamura, Toshihiko Kasahawa, Aya ShibaiAbstract:Three validation studies were conducted by the Japanese Society for Alternatives to Animal Experiments in order to assess the performance of a Skin Irritation assay using reconstructed human epidermis (RhE) LabCyte EPI-MODEL24 (LabCyte EPI-MODEL24 SIT) developed by the Japan Tissue Engineering Co., Ltd. (J-TEC), and the results of these studies were submitted to the Organisation for Economic Co-operation and Development (OECD) for the creation of a Test Guideline (TG). In the summary review report from the OECD, the peer review panel indicated the need to resolve an issue regarding the misclassification of 1-bromohexane. To this end, a rinsing operation intended to remove exposed chemicals was reviewed and the standard operating procedure (SOP) revised by J-TEC. Thereafter, in order to confirm general versatility of the revised SOP, a new validation management team was organized by the Japanese Center for the Validation of Alternative Methods (JaCVAM) to undertake a catch-up validation study that would compare the revised assay with similar in vitro Skin Irritation assays, per OECD TG No. 439 (2010). The catch-up validation and supplementary studies for LabCyte EPI-MODEL24 SIT using the revised SOPs were conducted at three laboratories. These results showed that the revised SOP of LabCyte EPI-MODEL24 SIT conformed more accurately to the classifications for Skin Irritation under the United Nations Globally Harmonised System of Classification and Labelling of Chemicals (UN GHS), thereby highlighting the importance of an optimized rinsing operation for the removal of exposed chemicals in obtaining consistent results from in vitro Skin Irritation assays. Copyright © 2013 John Wiley & Sons, Ltd.
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a catch up validation study of an in vitro Skin Irritation test method using reconstructed human epidermis labcyte epi model24
Journal of Applied Toxicology, 2014Co-Authors: Hajime Kojima, Masakazu Katoh, Shinsuke Shinoda, Tamie Suzuki, Yoshihiro Yamaguchi, Saori Hagiwara, Runa Izumi, Maki Nakamura, Toshihiko Kasahawa, Aya ShibaiAbstract:Three validation studies were conducted by the Japanese Society for Alternatives to Animal Experiments in order to assess the performance of a Skin Irritation assay using reconstructed human epidermis (RhE) LabCyte EPI-MODEL24 (LabCyte EPI-MODEL24 SIT) developed by the Japan Tissue Engineering Co., Ltd. (J-TEC), and the results of these studies were submitted to the Organisation for Economic Co-operation and Development (OECD) for the creation of a Test Guideline (TG). In the summary review report from the OECD, the peer review panel indicated the need to resolve an issue regarding the misclassification of 1-bromohexane. To this end, a rinsing operation intended to remove exposed chemicals was reviewed and the standard operating procedure (SOP) revised by J-TEC. Thereafter, in order to confirm general versatility of the revised SOP, a new validation management team was organized by the Japanese Center for the Validation of Alternative Methods (JaCVAM) to undertake a catch-up validation study that would compare the revised assay with similar in vitro Skin Irritation assays, per OECD TG No. 439 (2010). The catch-up validation and supplementary studies for LabCyte EPI-MODEL24 SIT using the revised SOPs were conducted at three laboratories. These results showed that the revised SOP of LabCyte EPI-MODEL24 SIT conformed more accurately to the classifications for Skin Irritation under the United Nations Globally Harmonised System of Classification and Labelling of Chemicals (UN GHS), thereby highlighting the importance of an optimized rinsing operation for the removal of exposed chemicals in obtaining consistent results from in vitro Skin Irritation assays.
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validation study of the in vitro Skin Irritation test with the labcyte epi model24
Atla-alternatives To Laboratory Animals, 2012Co-Authors: Hajime Kojima, Masakazu Katoh, Yoko Ando, Kenji Idehara, Tadashi Kosaka, Etsuyoshi Miyaoka, Shinsuke Shinoda, Tamie Suzuki, Yoshihiro Yamaguchi, Isao YoshimuraAbstract:A validation study on an in vitro Skin Irritation assay was performed with the reconstructed human epidermis (RhE) LabCyte EPI-MODEL24, developed by Japan Tissue Engineering Co. Ltd (Gamagori, Japan). The protocol that was followed in the current study was an optimised version of the EpiSkin protocol (LabCyte assay). According to the United Nations Globally Harmonised System (UN GHS) of classification for assessing the Skin Irritation potential of a chemical, 12 irritants and 13 non-irritants were validated by a minimum of six laboratories from the Japanese Society for Alternatives to Animal Experiments (JSAAE) Skin Irritation assay validation study management team (VMT). The 25 chemicals were listed in the European Centre for the Validation of Alternative Methods (ECVAM) performance standards. The reconstructed tissues were exposed to the chemicals for 15 minutes and incubated for 42 hours in fresh culture medium. Subsequently, the level of interleukin-1 alpha (IL-1 α) present in the conditioned medium was measured, and tissue viability was assessed by using the MTT assay. The results of the MTT assay obtained with the LabCyte EPI-MODEL24 (LabCyte MTT assay) demonstrated high within-laboratory and between-laboratory reproducibility, as well as high accuracy for use as a stand-alone assay to distinguish Skin irritants from non-irritants. In addition, the IL-1α release measurements in the LabCyte assay were clearly unnecessary for the success of this model in the classification of chemicals for Skin Irritation potential.
Helena Kandarova - One of the best experts on this subject based on the ideXlab platform.
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pre validation of an in vitro Skin Irritation test for medical devices using the reconstructed human tissue model epiderm
Toxicology in Vitro, 2018Co-Authors: Helena Kandarova, Wim H De Jong, J A Willoughby, M Bachelor, Silvia Letasiova, T Milasova, B Breyfogle, Yuki Handa, Liset J J De La Fonteyne, Kelly P. ColemanAbstract:Assessment of dermal Irritation is an essential component of the safety evaluation of medical devices. Reconstructed human epidermis (RhE) models have replaced rabbit Skin Irritation testing for neat chemicals and their mixtures (OECD Test Guideline 439). However, this guideline cannot be directly applied to the area of medical devices (MD) since their non-toxicity assessment is largely based on the testing of MD extracts that may have very low Irritation potential. Therefore, the RhE-methods previously validated with neat chemicals needed to be modified to reflect the needs for detection of low levels of potential irritants. A protocol employing RhE EpiDerm was optimized in 2013 using known irritants and spiked polymers (Casas et al., 2013, TIV). In 2014 and 2015 MatTek In Vitro Life Science Laboratories (IVLSL) and RIVM assessed the transferability of the assay. After the successful transfer and standardization of the protocol, 17 laboratories were trained in the use of the protocol in the preparation for the validation. Laboratories produced data with 98% agreement of predictions for the selected references and controls. We conclude that a modified RhE Skin Irritation test has the potential to address the Skin Irritation potential of the medical devices. Standardization and focus on the technical issues is essential for accurate prediction.
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round robin study to evaluate the reconstructed human epidermis rhe model as an in vitro Skin Irritation test for detection of irritant activity in medical device extracts
Toxicology in Vitro, 2018Co-Authors: Wim H De Jong, Helena Kandarova, Sebastian Hoffmann, Christian Pellevoisin, Yuji Haishima, Beau Rollins, Austin Zdawczyk, J A Willoughby, M Bachelor, Timothy SchatzAbstract:Abstract Assessment of Skin Irritation is an essential component of the safety evaluation of medical devices. OECD Test Guideline 439 describes the use of reconstructed human epidermis (RhE) as an in vitro test system for classification of Skin Irritation by neat chemicals. An international round robin study was conducted to evaluate the RhE method for determination of Skin irritant potential of medical device extracts. Four irritant polymers and three non-irritant controls were obtained or developed that had demonstrated their suitability to act as positive or negative test samples. The RhE tissues (EpiDerm™ and SkinEthic™ RHE) were dosed with 100 μL aliquots of either saline or sesame oil extract. Incubation times were 18 h (EpiDerm™) and 24 h (SkinEthic™ RHE). Cell viability reduction > 50% was indicative of Skin Irritation. Both the EpiDerm™ and SkinEthic™ RHE tissues were able to correctly identify virtually all of the irritant polymer samples either in the saline, sesame oil or both solvent extracts. Our results indicate that RhE tissue models can detect the presence of strong Skin irritants at low levels in dilute medical device polymer extracts. Therefore, these models may be suitable replacements for the rabbit Skin Irritation test to support the biological evaluation of medical devices.
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review of Skin Irritation corrosion hazards on the basis of human data a regulatory perspective
Interdisciplinary Toxicology, 2012Co-Authors: David Basketter, Dagmar Jirova, Helena KandarovaAbstract:Regulatory classification of Skin Irritation has historically been based on rabbit data, however current toxicology processes are transitioning to in vitro alternatives. The in vitro assays have to provide sufficient level of sensitivity as well as specificity to be accepted as replacement methods for the existing in vivo assays. This is usually achieved by comparing the in vitro results to classifications obtained in animals. Significant drawback of this approach is that neither in vivo nor in vitro methods are calibrated against human hazard data and results obtained in these assays may not correspond to situation in human. The main objective of this review was to establish an extended database of substances classified according to their human hazard to serve for further development of alternative methods relevant to human health as well as resource for improved regulatory classification. The literature has been reviewed to assemble all the available information on the testing of substances in the human 4 h human patch test, which is the only standardized protocol in humans matching the exposure conditions of the regulatory accepted in vivo rabbit Skin Irritation test. A total of 81 substances tested according to the defined 4 h human patch test protocol were found and collated into a dataset together with their existing in vivo classifications published in the literature. While about 50% of the substances in the database are classified as irritating based on the rabbit Skin test, on using the 4 h HPT test, less than 20% were identified as acutely irritant to human Skin. Based on the presented data, it can be concluded that the rabbit Skin Irritation test largely over-predicts human responses for the evaluated chemicals. Correct classification of the acute Skin Irritation hazard will only be possible if newly developed in vitro toxicology methods will be calibrated to produce results relevant to man.
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comparison of human Skin Irritation patch test data with in vitro Skin Irritation assays and animal data
Contact Dermatitis, 2010Co-Authors: D Jirova, David Basketter, M Liebsch, H Bendova, K Kejlova, Marie Marriott, Helena KandarovaAbstract:Background: Efforts to replace the rabbit Skin Irritation test have been underway for many years, encouraged by the EU Cosmetics Directive and REACH. Recently various in vitro tests have been developed, evaluated and validated. Objective: A key difficulty in confirming the validity of in vitro methods is that animal data are scarce and of limited utility for prediction of human effects, which adversely impacts their acceptance. This study examines whether in vivo or in vitro data most accurately predicted human effects. Methods: Using the 4-hr human patch test (HPT) we examined a number of chemicals whose EU classification of Skin irritancy is known to be borderline, or where in vitro methods provided conflicting results. Results: Of the 16 chemicals classified as irritants in the rabbit, only five substances were found to be significantly irritating to human Skin. Concordance of the rabbit test with the 4-hr HPT was only 56%, whereas concordance of human epidermis models with human data was 76% (EpiDerm) and 70% (EPISkin). Conclusions: The results confirm observations that rabbits overpredict Skin effects in humans. Therefore, when validating in vitro methods, all available information, including human data, should be taken into account before making conclusions about their predictive capacity.
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in vitro Skin Irritation testing improving the sensitivity of the epiderm Skin Irritation test protocol
Atla-alternatives To Laboratory Animals, 2009Co-Authors: Helena Kandarova, Joseph Kubilus, Patrick Hayden, Mitch Klausner, Paul Kearney, John SheasgreenAbstract:A Skin Irritation test (SIT) utilising a common protocol for two in vitro reconstructed human epidermal (RhE) models, EPISkin and EpiDerm, was developed, optimised and evaluated as a replacement for the in vivo rabbit Skin Irritation test in an ECVAM-sponsored validation study. In 2007, both RhE models were recognised by an independent peer-review panel and the ECVAM Scientific Advisory Committee (ESAC) as validated for use with the common SIT protocol. The EPISkin SIT was endorsed as a full replacement of the in vivo rabbit test. Since the EpiDerm SIT proved to be less sensitive than the in vivo test and the EPISkin SIT, the test was recognised as a validated component of a tiered testing strategy, in which positive results are accepted and negative results require further confirmation. The ESAC, in its April 2007 statement, also recommended increasing the sensitivity of the EpiDerm SIT, in order to gain the full acceptance. Analysis of the EpiDerm and EPISkin data from the ECVAM validation study indicated that the lower sensitivity of the EpiDerm SIT might be linked to the more robust barrier properties of the EpiDerm model. This hypothesis was also in line with results published previously. To overcome the relatively low sensitivity of the EpiDerm protocol as a hindrance to full regulatory acceptance, a modification of exposure conditions was introduced into the protocol to achieve better agreement with the in vivo rabbit data. In the Modified EpiDerm SIT protocol, the test chemical exposure time was increased from 15 minutes to 60 minutes. In addition, part of the exposure was performed at 37 degrees C. When the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) viability assay endpoint was used for classification, a significant increase of sensitivity was obtained (86.1%), whilst maintaining the high specificity of the method (76.3%). With the change to the EU classification system, which now uses higher cut-off for the classification of irritants, the sensitivity of the Modified EpiDerm SIT increased to above 90%. The measurement of interleukin (IL)-1alpha release did not further contribute to improvement of the method. The results demonstrate that the modified EpiDerm SIT protocol has the required sensitivity and specificity to be accepted as a stand alone method for complete replacement of the in vivo rabbit test.
David Basketter - One of the best experts on this subject based on the ideXlab platform.
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review of Skin Irritation corrosion hazards on the basis of human data a regulatory perspective
Interdisciplinary Toxicology, 2012Co-Authors: David Basketter, Dagmar Jirova, Helena KandarovaAbstract:Regulatory classification of Skin Irritation has historically been based on rabbit data, however current toxicology processes are transitioning to in vitro alternatives. The in vitro assays have to provide sufficient level of sensitivity as well as specificity to be accepted as replacement methods for the existing in vivo assays. This is usually achieved by comparing the in vitro results to classifications obtained in animals. Significant drawback of this approach is that neither in vivo nor in vitro methods are calibrated against human hazard data and results obtained in these assays may not correspond to situation in human. The main objective of this review was to establish an extended database of substances classified according to their human hazard to serve for further development of alternative methods relevant to human health as well as resource for improved regulatory classification. The literature has been reviewed to assemble all the available information on the testing of substances in the human 4 h human patch test, which is the only standardized protocol in humans matching the exposure conditions of the regulatory accepted in vivo rabbit Skin Irritation test. A total of 81 substances tested according to the defined 4 h human patch test protocol were found and collated into a dataset together with their existing in vivo classifications published in the literature. While about 50% of the substances in the database are classified as irritating based on the rabbit Skin test, on using the 4 h HPT test, less than 20% were identified as acutely irritant to human Skin. Based on the presented data, it can be concluded that the rabbit Skin Irritation test largely over-predicts human responses for the evaluated chemicals. Correct classification of the acute Skin Irritation hazard will only be possible if newly developed in vitro toxicology methods will be calibrated to produce results relevant to man.
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Skin Irritation, false positives and the local lymph node assay: A guideline issue?
Regulatory Toxicology and Pharmacology, 2011Co-Authors: David Basketter, Ian KimberAbstract:Since the formal validation and regulatory acceptance of the local lymph node assay (LLNA) there have been commentaries suggesting that the irritant properties of substances can give rise to false positives. As toxicology aspires to progress rapidly towards the age of in vitro alternatives, it is of increasing importance that issues relating to assay selectivity and performance are understood fully, and that true false positive responses are distinguished clearly from those that are simply unpalatable. In the present review, we have focused on whether Skin Irritation per se is actually a direct cause of true false positive results in the LLNA. The body of published work has been examined critically and considered in relation to our current understanding of the mechanisms of Skin Irritation and Skin sensitisation. From these analyses it is very clear that, of itself, Skin Irritation is not a cause of false positive results. The corollary is, therefore, that limiting test concentrations in the LLNA for the purpose of avoiding Skin Irritation may lead, unintentionally, to false negatives. Where a substance is a true false positive in the LLNA, the classic example being sodium lauryl sulphate, explanations for that positivity will have to reach beyond the seductive, but incorrect, recourse to its Skin Irritation potential.
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comparison of human Skin Irritation patch test data with in vitro Skin Irritation assays and animal data
Contact Dermatitis, 2010Co-Authors: D Jirova, David Basketter, M Liebsch, H Bendova, K Kejlova, Marie Marriott, Helena KandarovaAbstract:Background: Efforts to replace the rabbit Skin Irritation test have been underway for many years, encouraged by the EU Cosmetics Directive and REACH. Recently various in vitro tests have been developed, evaluated and validated. Objective: A key difficulty in confirming the validity of in vitro methods is that animal data are scarce and of limited utility for prediction of human effects, which adversely impacts their acceptance. This study examines whether in vivo or in vitro data most accurately predicted human effects. Methods: Using the 4-hr human patch test (HPT) we examined a number of chemicals whose EU classification of Skin irritancy is known to be borderline, or where in vitro methods provided conflicting results. Results: Of the 16 chemicals classified as irritants in the rabbit, only five substances were found to be significantly irritating to human Skin. Concordance of the rabbit test with the 4-hr HPT was only 56%, whereas concordance of human epidermis models with human data was 76% (EpiDerm) and 70% (EPISkin). Conclusions: The results confirm observations that rabbits overpredict Skin effects in humans. Therefore, when validating in vitro methods, all available information, including human data, should be taken into account before making conclusions about their predictive capacity.
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Skin Irritation and sensitization: mechanisms and new approaches for risk assessment. 1. Skin Irritation.
Skin Pharmacology and Physiology, 2008Co-Authors: Razvigor Darlenski, Angelova-fischer I, Nikolai Tsankov, David BasketterAbstract:: Cutaneous Irritation presents a major health problem with serious social and occupational impact. The interaction between an irritant and the human Skin depends on multiple factors: the intrinsic properties and the nature of the irritant itself, and specific individual- and environment-related variables. The main pathological mechanisms of irritancy include Skin barrier disruption, induction of a cytokine cascade and involvement of the oxidative stress network; all of them resulting in a visible or subclinical inflammatory reaction. In vivo, different non-invasive parameters for the evaluation of Skin Irritation and irritant potential of compounds and their specific formulations have been introduced, such as epidermal barrier function, Skin hydration, surface pH, lipid composition, Skin colour and Skin blood flow. The diverse physiological changes caused by irritating agents require implementation of a multiparametric approach in the evaluation of cutaneous irritancy.
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determination of Skin Irritation potential in the human 4 h patch test
Contact Dermatitis, 2004Co-Authors: David Basketter, Michael York, J.p. Mcfadden, Michael K RobinsonAbstract:Recently adopted legislation in Europe has increased the focus that must be placed on the development of in vitro alternatives to the traditional toxicology tests employed to identify the human health hazards associated with chemicals. Included in these is the rabbit Skin-Irritation test which is used to discriminate those substances which possess significant acute Skin Irritation potential from those which are of more limited Irritation potential. So far, the considerable efforts to replace this assay with in vitro alternatives have not been successful, which may in part be due to the relatively poor quality of the existing in vivo dataset. To help address this problem, we have elected to present our complete database of information on the Skin Irritation potential of some 65 substances, all of which have been tested in a standard human 4-h patch test. These provide a high quality dataset, generated in man (the goal of toxicologists' health protection-related activities). The data are presented in the context of results with a concurrent positive Skin Irritation control to ensure that results from individual experiments can be correlated. Consequently, in vitro or in silico alternatives which can identify the significant acute human Skin irritants in this group may well represent suitable alternatives to the rabbit.
Aya Shibai - One of the best experts on this subject based on the ideXlab platform.
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a catch up validation study of an in vitro Skin Irritation test method using reconstructed human epidermis labcyte epi model24
Journal of Applied Toxicology, 2014Co-Authors: Hajime Kojima, Masakazu Katoh, Shinsuke Shinoda, Tamie Suzuki, Yoshihiro Yamaguchi, Saori Hagiwara, Runa Izumi, Maki Nakamura, Toshihiko Kasahawa, Aya ShibaiAbstract:Three validation studies were conducted by the Japanese Society for Alternatives to Animal Experiments in order to assess the performance of a Skin Irritation assay using reconstructed human epidermis (RhE) LabCyte EPI-MODEL24 (LabCyte EPI-MODEL24 SIT) developed by the Japan Tissue Engineering Co., Ltd. (J-TEC), and the results of these studies were submitted to the Organisation for Economic Co-operation and Development (OECD) for the creation of a Test Guideline (TG). In the summary review report from the OECD, the peer review panel indicated the need to resolve an issue regarding the misclassification of 1-bromohexane. To this end, a rinsing operation intended to remove exposed chemicals was reviewed and the standard operating procedure (SOP) revised by J-TEC. Thereafter, in order to confirm general versatility of the revised SOP, a new validation management team was organized by the Japanese Center for the Validation of Alternative Methods (JaCVAM) to undertake a catch-up validation study that would compare the revised assay with similar in vitro Skin Irritation assays, per OECD TG No. 439 (2010). The catch-up validation and supplementary studies for LabCyte EPI-MODEL24 SIT using the revised SOPs were conducted at three laboratories. These results showed that the revised SOP of LabCyte EPI-MODEL24 SIT conformed more accurately to the classifications for Skin Irritation under the United Nations Globally Harmonised System of Classification and Labelling of Chemicals (UN GHS), thereby highlighting the importance of an optimized rinsing operation for the removal of exposed chemicals in obtaining consistent results from in vitro Skin Irritation assays.
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a catch up validation study of an in vitro Skin Irritation test method using reconstructed human epidermis labcyte epi model24
Journal of Applied Toxicology, 2014Co-Authors: Hajime Kojima, Masakazu Katoh, Shinsuke Shinoda, Tamie Suzuki, Yoshihiro Yamaguchi, Saori Hagiwara, Runa Izumi, Maki Nakamura, Toshihiko Kasahawa, Aya ShibaiAbstract:Three validation studies were conducted by the Japanese Society for Alternatives to Animal Experiments in order to assess the performance of a Skin Irritation assay using reconstructed human epidermis (RhE) LabCyte EPI-MODEL24 (LabCyte EPI-MODEL24 SIT) developed by the Japan Tissue Engineering Co., Ltd. (J-TEC), and the results of these studies were submitted to the Organisation for Economic Co-operation and Development (OECD) for the creation of a Test Guideline (TG). In the summary review report from the OECD, the peer review panel indicated the need to resolve an issue regarding the misclassification of 1-bromohexane. To this end, a rinsing operation intended to remove exposed chemicals was reviewed and the standard operating procedure (SOP) revised by J-TEC. Thereafter, in order to confirm general versatility of the revised SOP, a new validation management team was organized by the Japanese Center for the Validation of Alternative Methods (JaCVAM) to undertake a catch-up validation study that would compare the revised assay with similar in vitro Skin Irritation assays, per OECD TG No. 439 (2010). The catch-up validation and supplementary studies for LabCyte EPI-MODEL24 SIT using the revised SOPs were conducted at three laboratories. These results showed that the revised SOP of LabCyte EPI-MODEL24 SIT conformed more accurately to the classifications for Skin Irritation under the United Nations Globally Harmonised System of Classification and Labelling of Chemicals (UN GHS), thereby highlighting the importance of an optimized rinsing operation for the removal of exposed chemicals in obtaining consistent results from in vitro Skin Irritation assays. Copyright © 2013 John Wiley & Sons, Ltd.
Nathalie Alepee - One of the best experts on this subject based on the ideXlab platform.
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In vitro Skin Irritation assessment becomes a reality in China using a reconstructed human epidermis test method
Toxicology in Vitro, 2017Co-Authors: Nan Li, Lingyan Zhong, Yanfeng Liu, Jose Cotovio, Nathalie Alepee, Jie Qiu, Zhenzi CaiAbstract:The in vitro EpiSkin™ test method was validated in 2007 by the European Union Reference Laboratory for alternatives to animal testing (EURL ECVAM) as a full replacement method for the Draize acute Skin Irritation test and adopted in the OECD Test Guideline 439 in 2009. Based on the EpiSkin™ technology, the production of a reconstructed epidermis model has been established and standardized in China. The evaluation of the in vitro Skin Irritation test method using this EpiSkin™ model produced in China was performed on a set of 45 chemicals. Good predictive capacity was obtained with 94% (n = 17) for sensitivity, 75% (n = 28) for specificity and 82% for accuracy. The accuracy of the included 20 OECD reference chemicals also met the OECD acceptance criteria, indicating that this testing method based on the EpiSkin™ model produced in China can be used as a stand-alone test method to predict Skin Irritation. The availability and validity of in vitro epidermis model and testing method are of great significance for extending the applications of non-animal alternative testing methods in China.
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assessment of the optimized Skinethic reconstructed human epidermis rhe 42 bis Skin Irritation protocol over 39 test substances
Toxicology in Vitro, 2010Co-Authors: Carine Tornier, Carole Amsellem, Anne De Brugerolle De Fraissinette, Nathalie AlepeeAbstract:Abstract The development of in vitro protocols able to discriminate Skin irritants from non-irritants integrates the toxicologists’ needs for reliable and robust in vitro tools for screening test substances. Based on EpiSkin™ test method, validated by ESAC (ECVAM Scientific Advisory Committee) in April 2007 as the Draize Skin Irritation replacement reference test method, we present and discuss here the results obtained by adapting protocols to the SkinEthic™ Reconstructed Human Epidermis (RHE) model. The main adaptations of the validated reference protocol consists in a modulated exposure time (15, 42 or 60 min) followed by a rinsing step and a 42 h post-incubation period before quantitative measurement of cell viability by MTT reduction. The results obtained with a set of 39 test substances allowed to determine a prediction model with a cut-off of 50%. The best reliability was obtained with the proposed “42 bis” (42 min + 42 h) test method. An overall accuracy of 85% was reached when testing the 20 ECVAM selected reference test substances. The performance of this optimized test method was confirmed by its higher robustness compared to other proposed protocols. As such, none of test substances showed a standard deviation above 18%. This optimized Skin Irritation protocol has thus been established according to the ECVAM intra-laboratory minimum performance standards.
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a catch up validation study on reconstructed human epidermis Skinethic rhe for full replacement of the draize Skin Irritation test
Toxicology in Vitro, 2010Co-Authors: Nathalie Alepee, Carine Tornier, Carole Amsellem, Cecile Robert, Mariehelene Roux, Olivier Doucet, Jean Pachot, Marisa Meloni, Anne De Brugerolle De FraissinetteAbstract:Abstract Efforts to fully replace the in vivo Draize Skin Irritation test, according to the Directive 67/548/ECC or OECD TG 404, were reinforced with the seventh Amendment of the Cosmetic Directive and the REACh regulation. In 2007, the EpiSkin™ test method was scientifically validated and recognized as the stand alone method to discriminate Skin irritants (R38) from non-irritants (no label) according to the definition of the EU risk phrases. An ECVAM performance standards (PS) document was defined to evaluate the accuracy and reliability of other analogous test methods (ECVAM SIVS, May 2007). The present test was designed to determine the reliability and relevance of the Reconstructed Human Epidermis (RHE) model commercialized by SkinEthic™. The RHE Skin Irritation test method consisted to topically apply topically the test substances for 42 min followed by a 42 h post-incubation. The main selected endpoint was the cell viability (MTT reduction), with a threshold of 50% viability. The RHE test method showed a good intra and inter-laboratory reproducibilities in a multicentric study involving three independent laboratories. The SkinEthic™ RHE test method showed to be relevant and reliable with a sensitivity of 90% and a specificity of 80% (MTT only) and was not improved by integrating another endpoint such as IL-1α. The overall accuracy was 85% resulting in the recognition of the SkinEthic™ RHE test method, by the ECVAM Scientific Advisory Committee in November 2008, as a stand alone replacement test method for the Draize rabbit in vivo test, as a screen, or as part of a sequential testing strategy in a weight of evidence approach, for classifying non-irritant and irritant test substances, depending on country requirements.
