Implementation, availability and regulatory status of an OECD accepted Reconstructed Human Epidermis model in Brazil

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.TÍTULO PT: Implementação, disponibilidade e contexto regulatório de um modelo de Epiderme Humana Reconstruída no Brasil aceito pela OECDIntrodução: Em 2014, o Brasil aderiu à crescente lista de países a banir testes de produtos cosméticos em modelos animais. A nova legislação entra em vigor em 2019. Como resultado, o interesse em métodos de testes alternativos validados para avaliação de segurança tem aumentado na academia, indústria e associações. No entanto, a falta de legislação específica sobre o uso de material biológico de origem humana para testes toxicológicos dificulta o acesso aos modelos alternativos in vitro. Além disso, a importação no Brasil não é possível em tempo hábil. Método: Neste artigo, relatamos o processo de implementação de um modelo de Epiderme Humana Reconstruída (SkinEthic™ RHE) internacionalmente aceito pela OECD, através de uma transferência tecnológica da Episkin Lion para o Brasil, bem como discutimos a evolução regulatória que tem motivado a implementação e a ampla utilização de métodos alternativos à experimentação animal em diversos segmentos além do cosmético e farmacêutico. Resultados: O protocolo de fabricação dos tecidos mostrou-se robusto e altamente reprodutível, considerando os parâmetros de controle de qualidade (análise histológica, função barreira e viabilidade tecidual) analisados em 24 lotes fabricados no Brasil. Conclusões: A implementação do modelo SkinEthic™ RHE é apenas um primeiro e importante passo em direção a uma nova abordagem para testes de segurança toxicológica no Brasil, realizada com êxito e aqui relatada. No entanto, para seguir plenamente a nova legislação até 2019, a disponibilidade de modelos validados é essencial. Os testes de controle de qualidade realizados nos lotes RHE produzidos no Brasil demonstram que o modelo atende aos critérios de aceitação da OCDE e, portanto, pode ser usado para uma previsão confiável de irritação e classificação de compostos corrosivos

TGFβ signaling regulates lipogenesis in human sebaceous glands cells

Background: Sebaceous glands are components of the skin essential for its normal lubrication by the production of sebum. This contributes to skin health and more importantly is crucial for the skin barrier function. A mechanistic understanding of sebaceous gland cells growth and differentiation has lagged behind that for keratinocytes, partly because of a lack of an in vitro model that can be used for experimental manipulation. Methods: We have developed an in vitro culture model to isolate and grow primary human sebocytes without transformation that display functional characteristics of sebocytes. We used this novel method to probe the effect of Transforming Growth Factor β (TGFβ) signaling on sebocyte differentiation, by examining the expression of genes involved in lipogenesis upon treatment with TGFβ1. We also repressed TGFβ signaling through knockdown of the TGFβ Receptor II to address if the effect of TGFβ activation is mediated via canonical Smad signal transduction. Results: We find that activation of the TGFβ signaling pathway is necessary and sufficient for maintaining sebocytes in an undifferentiated state. The presence of TGFβ ligand triggered decreased expression in genes required for the production of characteristics sebaceous lipids and for sebocyte differentiation such as FADS2 and PPARγ, thereby decreasing lipid accumulation through the TGFβ RII-Smad2 dependent pathway. Conclusion: TGFβ signaling plays an essential role in sebaceous gland regulation by maintaining sebocytes in an undifferentiated state. This data was generated using a novel method for human sebocyte culture, which is likely to prove generally useful in investigations of sebaceous gland growth and differentiation. These findings open a new paradigm in human skin biology with important implications for skin therapies

Les lysyl oxydases dans le derme et l'épiderme de la peau humaine, saine ou tumorale, et dans la peau reconstruite

La lysyl oxydase LOX et ses 4 isoformes (LOXL 1-4) composent la famille des lysyl oxydases. LOX est impliquée dans plusieurs processus tels que la réticulation des collagènes fibrillaires et l'élastine ainsi que dans la suppression de l'activité oncogénique de ras et l'invasion des cellules tumorales. Notre recherche porte sur l'expression de LOX et de LOXL et leur rôle respectif dans la collagénogénèse et l'élastogénèse, dans la peau normale et dans la peau reconstruite que nous avons optimisée. Nos résultats démontrent l'implication de LOXL dans l'élastogénèse et le maintien du tissu élastique dans la peau humaine. Ces résultats ont été confirmés au cours de l'embryogenèse et du viellissement de l'aorte de rat. L'expression inattendue de LOX dans les kératinocytes soulève la question de son rôle dans l'épiderme. Nous avons recherché son expression dans les cancers cutanés basocellulaires et spinocellulaires ainsi que l'effet de l'inhibition de son activité ou de sa synthèse dans notre modèle de peau reconstruite. Les résultats indiquent un rôle prépondérant de la protéine LOX dans la progression tumorale des kératinocytes. Cependant même si l'inhibition de l'activité enzymatique est incapable à elle seule d'induire une invasion, ses effets favorisant une déviation vers un phénotype tumoral ne peuvent être écartésLYON1-BU.Sciences (692662101) / SudocSudocFranceF

Endocannabinoids Regulate Growth and Survival of Human Eccrine Sweat Gland-Derived Epithelial Cells

The functional existence of the emerging endocannabinoid system (ECS), one of the new neuroendocrine players in cutaneous biology, is recently described in the human skin. In this study, using human eccrine sweat gland–derived immortalized NCL-SG3 model cells and a wide array of cellular and molecular assays, we investigated the effects of prototypic endocannabinoids (anandamide, 2-arachidonoylglycerol) on cellular functions. We show here that both endocannabinoids dose-dependently suppressed proliferation, induced apoptosis, altered expressions of various cytoskeleton proteins (e.g., cytokeratins), and upregulated lipid synthesis. Interestingly, as revealed by specific agonists and antagonists as well as by RNA interference, neither the metabotropic cannabinoid receptors (CB) nor the “ionotropic” CB transient receptor potential ion channels, expressed by these cells, mediated the cellular actions of the endocannabinoids. However, the endocannabinoids selectively activated the mitogen-activated protein kinase signaling pathway. Finally, other elements of the ECS (i.e., enzymes involved in the synthesis and degradation of endocannabinoids) were also identified on NCL-SG3 cells. These results collectively suggest that cannabinoids exert a profound regulatory role in the biology of the appendage. Therefore, from a therapeutic point of view, upregulation of endocannabinoid levels might help to manage certain sweat gland–derived disorders (e.g., tumors) characterized by unwanted growth

A multi-study analysis enables identification of potential microbial features associated with skin aging signs.

Introduction: During adulthood, the skin microbiota can be relatively stable if environmental conditions are also stable, yet physiological changes of the skin with age may affect the skin microbiome and its function. The microbiome is an important factor to consider in aging since it constitutes most of the genes that are expressed on the human body. However, severity of specific aging signs (one of the parameters used to measure apparent age) and skin surface quality (e.g., texture, hydration, pH, sebum, etc.) may not be indicative of chronological age. For example, older individuals can have young looking skin (young apparent age) and young individuals can be of older apparent age. Methods: Here we aim to identify microbial taxa of interest associated to skin quality/aging signs using a multi-study analysis of 13 microbiome datasets consisting of 16S rRNA amplicon sequence data and paired skin clinical data from the face. Results: We show that there is a negative relationship between microbiome diversity and transepidermal water loss, and a positive association between microbiome diversity and age. Aligned with a tight link between age and wrinkles, we report a global positive association between microbiome diversity and Crows feet wrinkles, but with this relationship varying significantly by sub-study. Finally, we identify taxa potentially associated with wrinkles, TEWL and corneometer measures. Discussion: These findings represent a key step towards understanding the implication of the skin microbiota in skin aging signs

Image6_A multi-study analysis enables identification of potential microbial features associated with skin aging signs.tiff

Introduction: During adulthood, the skin microbiota can be relatively stable if environmental conditions are also stable, yet physiological changes of the skin with age may affect the skin microbiome and its function. The microbiome is an important factor to consider in aging since it constitutes most of the genes that are expressed on the human body. However, severity of specific aging signs (one of the parameters used to measure “apparent” age) and skin surface quality (e.g., texture, hydration, pH, sebum, etc.) may not be indicative of chronological age. For example, older individuals can have young looking skin (young apparent age) and young individuals can be of older apparent age.Methods: Here we aim to identify microbial taxa of interest associated to skin quality/aging signs using a multi-study analysis of 13 microbiome datasets consisting of 16S rRNA amplicon sequence data and paired skin clinical data from the face.Results: We show that there is a negative relationship between microbiome diversity and transepidermal water loss, and a positive association between microbiome diversity and age. Aligned with a tight link between age and wrinkles, we report a global positive association between microbiome diversity and Crow’s feet wrinkles, but with this relationship varying significantly by sub-study. Finally, we identify taxa potentially associated with wrinkles, TEWL and corneometer measures.Discussion: These findings represent a key step towards understanding the implication of the skin microbiota in skin aging signs.</p

Image4_A multi-study analysis enables identification of potential microbial features associated with skin aging signs.tiff

Introduction: During adulthood, the skin microbiota can be relatively stable if environmental conditions are also stable, yet physiological changes of the skin with age may affect the skin microbiome and its function. The microbiome is an important factor to consider in aging since it constitutes most of the genes that are expressed on the human body. However, severity of specific aging signs (one of the parameters used to measure “apparent” age) and skin surface quality (e.g., texture, hydration, pH, sebum, etc.) may not be indicative of chronological age. For example, older individuals can have young looking skin (young apparent age) and young individuals can be of older apparent age.Methods: Here we aim to identify microbial taxa of interest associated to skin quality/aging signs using a multi-study analysis of 13 microbiome datasets consisting of 16S rRNA amplicon sequence data and paired skin clinical data from the face.Results: We show that there is a negative relationship between microbiome diversity and transepidermal water loss, and a positive association between microbiome diversity and age. Aligned with a tight link between age and wrinkles, we report a global positive association between microbiome diversity and Crow’s feet wrinkles, but with this relationship varying significantly by sub-study. Finally, we identify taxa potentially associated with wrinkles, TEWL and corneometer measures.Discussion: These findings represent a key step towards understanding the implication of the skin microbiota in skin aging signs.</p