Assessment of ocular irritation risk is an international regulatory requirement in the safety evaluation of products. In response to this need, L'Oréal developed the SkinEthic™ Human Corneal Epithelium (HCE) Eye Irritation Test (EIT) that has been included in OECD Test Guideline 492. SkinEthic™ HCE EIT is able to correctly and reliably identify chemicals not requiring classification versus labelling for eye irritation or serious eye damage according to UN GHS. In an effort to promote its global use, the performance of the method was evaluated after long-distance shipment and compared to European shipment conditions. Results obtained by Cosmos Technical Center (Japan) after extended tissues transit were compared to results obtained in L'Oréal (France). Thirty-nine out of 40 blinded chemicals, representing different functional chemical classes, were consistently classified in both laboratories. The SkinEthic™ HCE EIT test method was also evaluated for its performance after extended storage of the tissues. The performance was in agreement with the values reported in OECD TG 492, with an overall accuracy of 87.1% (based on 119 chemicals), sensitivity of 95.5% and specificity of 73.5%. The reliability and relevance of SkinEthic™ HCE EIT test method after long-distance shipment and extended storage remain in agreement with regulatory validation criteria.
The goal of human-on-a-chip systems is to capture multi-organ complexity and predict the human response to compounds within physiologically relevant platforms. The generation and characterization of such systems is currently a focal point of research given the long-standing inadequacies of conventional techniques for predicting human outcome. Functional systems can measure and quantify key cellular mechanisms that correlate with the physiological status of a tissue, and can be used to evaluate therapeutic challenges utilizing many of the same endpoints used in animal experiments or clinical trials. Culturing multiple organ compartments in a platform creates a more physiologic environment (organ-organ communication). Here is reported a human 4-organ system composed of heart, liver, skeletal muscle and nervous system modules that maintains cellular viability and function over 28 days in serum-free conditions using a pumpless system. The integration of non-invasive electrical evaluation of neurons and cardiac cells and mechanical determination of cardiac and skeletal muscle contraction allows the monitoring of cellular function especially for chronic toxicity studies in vitro. The 28 day period is the minimum timeframe for animal studies to evaluate repeat dose toxicity. This technology could be a relevant alternative to animal testing by monitoring multi-organ function upon long term chemical exposure.
The purpose of present study was to investigate the applicability of reconstructed human epidermis model to identify skin corrosive UN GHS Categories 1A, 1B/1C and non-corrosive chemicals in China. By using a commercialized reconstructed human epidermis model, China EpiSkin™ which had been proven to be applicable as a stand-alone test method to predict skin irritation in previous study, the predictive capacity of corrosion was assessed with 76 chemicals that included 30 reference chemicals recommended by OECD TG 431 in this study. The latter reference chemicals were tested in three runs, the within-laboratory reproducibility reached 100%, the accuracy was 90% for distinguishing corrosive and non-corrosive chemicals and 80% for sub-categorization (Cat. 1A vs Cat. 1B/1C vs non corrosive). Additional 46 chemicals were also tested, and the overall accuracy for sub-categorization of all 76 tested chemicals was 80.3% with 91.7% sensitivity for Category 1A, 82.1% sensitivity for category 1B/1C and 75% specificity which met all required predictive capacity by OECD. The present study results show that China EpiSkin™ model can be applied to predict sub-categorization 1A and 1B/1C of corrosive chemicals. The availability of skin corrosion in vitro test method provides the applicability of in vitro non-animal testing method for chemicals widely used in various industries, and will further support the implementation and promotion of alternative methods in China.
Predictive capacity of the EpiSkin™ model was evaluated on 87 chemicals using the Bottom-Up and the Top-Down testing approaches recommended within Integrated Approach on Testing and Assessment for the identification of both skin irritation and corrosion hazards. Classified (UN GHS Cat. 1 and Cat. 2) chemicals were identified with a very high sensitivity (≥94%) and the non-classified (UN GHS Cat. 3 and No Cat.) chemicals with an appropriate specificity (70%). Very high sensitivities were obtained for the identification of Cat. 1 chemicals (≥98%), very high specificities for non-Cat. 1 chemicals (93%), and accuracies of −95% for the identification of skin corrosives vs. non-corrosives by both approaches. Overall accuracies of 72% were found for predicting the single (sub)categories: non-classified, Cat. 2, Subcat. 1B/1C and Subcat. 1A. Results indicated the testing strategies to be more predictive than the individual assays on a conservative safety approach. Finally, no extreme misclassifications (no under-prediction of in vivo Subcat. 1A as non-Cat. 1, and no over-prediction of non-classified chemical as Subcat. 1A) occur. These findings, independently of the approach used, confirm the usefulness of the EpiSkin™ in vitro model for a safe prediction of the skin irritant and corrosive hazards of chemicals.
Introduction: In 2014, Brazil has joined the growing list of countries to ban cosmetic products from being tested on animal models. The new legislation comes into force in 2019. As a result, the interest for validated alternative testing methods for safety assessment has been increasing in academia, industry and associations. However, the lack of specific legislation on the use of biological material of human origin for toxicological tests makes the access to alternative in vitro models difficult. Furthermore, importation to Brazil is not possible on timely manner. Method: In this article, we report the implementation process of a Reconstructed Human Epidermis (SkinEthic™ RHE), an alternative model internationally accepted by OECD, through a technology transfer from EPISKIN® Lyon to Brazil. Regulatory evolution has been motivating the implementation and wide use of alternative methods to animal testing in several industry segments including cosmetic and pharmaceutical. Results: Protocol has been shown to be robust and highly reproducible. Quality control parameters (histological analysis, barrier function test and tissue viability) were performed on 24 batches assembled in Brazil. SkinEthic™ RHE model use allows the full replacement of animal test methods for skin hazards identification. It has regulatory acceptance for several toxicological endpoints, such as the Draize test for skin irritation and corrosion. It allows the reduction and refining of pre-clinical protocols through tiered strategies. Implementation of SkinEthic™ RHE protocol is just a first and important step towards a new approach of toxicological safety testing in Brazil. Conclusion: The implementation was successfully done and reported here. However, in order to follow completely the new legislation up to 2019, the availability of validated models is essential. Quality control tests done on RHE batches produced in Brazil demonstrate that the model met OECD acceptance criteria and therefore can be used for reliable prediction of irritation and corrosion classification.
Skin engineering is a powerful and highly versatile technology used at all stages of a cosmetic product development. The contributions of reconstructed skin are significant in many areas of research, for example, UV sensitivity, specific ethnic characteristics, skin allergy, skin aging, and skin microbiome. The ability to reproduce several functions of the human skin in vitro broadens the scope for industrial applications. Thanks to in vitro skin models, it is now possible to predict, early in their development process, some positive or negative effects of cosmetics without the need of animal testing. Reconstructed epidermis and skin tissues represent a potential strong driver for the development of in vitro methods to face this new paradigm in toxicology. To date, several in vitro methods have been developed to assess different toxicological end points, some of which have been validated and recognized by the regulatory bodies concerned. Reconstructed human skin is also an unbeatable tool for screening and assessing the efficacy of new active ingredients, deciphering their mechanism of action, and, finally, optimizing the composition of formulations to maximize in vivo benefits.
New translational kidney safety biomarkers are now enabling drug development by: 1) enhancing safety monitoring of patients in early clinical trials for toxicities seen in animal studies that are of questionable human relevance, 2) providing early insights to pathogenic mechanisms leading to drug induced kidney injury in early drug development toxicology studies, and 3) assisting early compound selection and animal de-risking studies that reduce the probability of later attrition due to kidney toxicity. Several consortia including the FNIH Biomarker Consortium Kidney Safety Biomarker Project Team are presently collaborating on additional progressive qualification efforts in partnership with regulatory agencies and academia to further advance the qualification of novel translational renal safety biomarkers using samples from retrospective observational clinical studies in a learning mode, and prospectively designed confirmatory clinical studies. VII-1-829
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.
Serological tests are used widely in veterinary practice; most often in the diagnosis of infectious disease. Such tests may be used to detect antigen from an infectious agent within a biological sample or to detect the presence of serum antibody specific for the pathogen as evidence of immunological exposure. These tests are all based on the fundamental principles of interaction between antigenic epitopes and antibodies of either the immunoglobulin (Ig) G, IgM, IgA, or IgE classes. The relative concentration of specific antibody within a sample is traditionally determined by calculation of the titer of antibody. With few exceptions, the primary interaction between an antigen and antibody in vitro cannot be visualized and so serological tests generally employ a secondary indicator system based on the use of a polyclonal antiserum or monoclonal antibody. A range of such tests has been developed, but many in veterinary medicine are based on the principle of the enzyme-linked immunosorbent assay, which is described in detail in this article. The interpretation of serological tests must be made carefully, taking into consideration the sensitivity and specificity of the test and the possible reasons for false-positive and false-negative outcomes.
HeeSeok Lee1, YongSun Song1, Jin-Hyang Suh1, Min-Ki Shin1, Yoon Jae Cho1, Hyun-Suk Oh1, Myung-Sil Hwang1, Guiim Moon1, Yooheon Park2, Jin-Hwan Hong1 and Yong Eui Koo1 1Food Safety Risk Assessment Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Chungcheongbuk-do, South Korea; 2Research Institute of Biotechnology & Medical Converged Science, Dongguk University, Seoul, South Korea hslee0515@gmail.com
Horizontal gene transfer (HGT) is a major part of the evolution of Archaea and Bacteria, to the extent that the validity of the Tree of Life concept for prokaryotes has been seriously questioned. The patterns and routes of HGT remain a subject of intense study and debate. It was discovered that while several genes exhibit rampant HGT across the whole prokaryotic tree of life, others are lethal to certain organisms and therefore cannot be successfully transferred to them. We distinguish between these two classes of genes and show analytically that genes found to be toxic to a specific species (E. coli) also resist HGT in general. Several tools we employ show evidence to support that claim. One of those tools is the quartet plurality distribution (QPD), a mathematical tool that measures tendency to HGT over a large set of genes and species. When aggregated over a collection of genes, it can reveal important properties of this collection. We conclude that evidence of toxicity of certain genes to a wide variety of prokaryotes are revealed using the new tool of quartet plurality distribution.
This review discusses hemoglobin D-Punjab, also known as hemoglobin D-Los Angeles, one of the most common hemoglobin variants worldwide. It is derived from a point mutation in the beta-globin gene (HBB: c.364G>C; rs33946267) prevalent in the Punjab region, Northwestern Indian. Hemoglobin D-Punjab can be inherited in heterozygosis with hemoglobin A causing no clinical or hematological alterations, or in homozygosis, the rarest form of inheritance, a condition that is commonly not related to clinical symptomatology. Moreover, this variant can exist in association with other hemoglobinopathies, such as thalassemias; the most noticeable clinical alterations occur when hemoglobin D-Punjab is associated to hemoglobin S. The clinical manifestations of this association can be similar to homozygosis for hemoglobin S. Although hemoglobin D-Punjab is a common variant globally with clinical importance especially in cases of double heterozygosis, hemoglobin S/D-Punjab is still understudied. In Brazil, for example, hemoglobin D-Punjab is the third most common hemoglobin variant. Thus, this paper summarizes information about the origin, geographic distribution, characterization and occurrence of hemoglobin D-Punjab haplotypes to try to improve our knowledge of this variant. Moreover, a list of the main techniques used in its identification is provided emphasizing the importance of complementary molecular analysis for accurate diagnosis.
We report on a functional human model to evaluate multi-organ toxicity in a 4-organ system under continuous flow conditions in a serum-free defined medium utilizing a pumpless platform for 14 days. Computer simulations of the platform established flow rates and resultant shear stress within accepted ranges. Viability of the system was demonstrated for 14 days as well as functional activity of cardiac, muscle, neuronal and liver modules. The pharmacological relevance of the integrated modules were evaluated for their response at 7 days to 5 drugs with known side effects after a 48 hour drug treatment regime. The results of all drug treatments were in general agreement with published toxicity results from human and animal data. The presented phenotypic culture model exhibits a multi-organ toxicity response, representing the next generation of in vitro systems and constitutes a step towards an in vitro “human-on-a-chip” assay for systemic toxicity screening.
In spite of over 20 years of effort, no single in vitro assay has been developed and validated as a full regulatory replacement for the Draize Eye Irritation test. However, companies have been using in vitro methods to screen new formulations and in some cases as their primary assessment of eye irritation potential for many years. The present report shows the outcome of an Expert Meeting convened by the European Centre for the Validation of Alternative Methods in February 2005 to identify test strategies for eye irritation. In this workshop test developers/users were requested to nominate methods to be considered as a basis for the identification of such testing strategies. Assays were evaluated and categorized based on their proposed applicability domains (e.g., categories of irritation severity, modes of action, chemical class, physicochemical compatibility). The analyses were based on the data developed from current practice and published studies, the ability to predict depth of injury (within the applicable range of severity), modes of action that could be addressed and compatibility with different physiochemical forms. The difficulty in predicting the middle category of irritancy (e.g. R36, GHS Categories 2A and 2B) was recognized. The testing scheme proposes using a Bottom–Up (begin with using test methods that can accurately identify non-irritants) or Top–Down (begin with using test methods that can accurately identify severe irritants) progression of in vitro tests (based on expected irritancy). Irrespective of the starting point, the approach would identify non-irritants and severe irritants, leaving all others to the (mild/moderate) irritant GHS 2/R36 categories.
Novel indium-doped brookite phase TiO2 films with different In concentrations were successfully prepared on the yttria-stabilized zirconia (YSZ) (110) substrates by the metal organic chemical vapor deposition (MOCVD) technique. The structural, morphological, electrical and optical properties of the films were investigated in detail. X-ray diffraction analysis revealed that all the films with different In concentrations were pure brookite phase TiO2 with only one orientation along the b-TiO2 (120) direction. The resistivity of the films was reduced by almost eight orders of magnitude by In doping with the lowest resistivity of 7.4 × 10−2Ω⋅cm and a mobility of 8.3 cm2 V−1 s−1 obtained for the 2.6% In-doped b-TiO2film. The average optical transmittance of the 2.6% In-doped sample exceeded 74% in the visible range and the optical band gap was about 3.60 eV.