A human skin model to evaluate the protective effect of compounds against UVA damage.

OBJECTIVE: The main function of skin is to protect the body from external aggressions. Over time, normal skin ageing is accelerated by external stresses such as smoking, pollution, chemical products and radiation. UV light, in particular UVA, causes DNA damage, apoptosis and morphological modifications, which are responsible for both premature ageing and cancer. The aim of this study was to establish a discriminatory and sufficiently reproducible cutaneous model for evaluating UVA damage, to enable testing for effectiveness of potentially protective compounds. METHODS: The cutaneous model is based on Human skin explants irradiated with UVA. Deleterious effects on epidermis were observed and quantified by haematoxylin-eosin staining and by immunofluorescence of ɣ-H2Ax, cytokeratin 5, involucrin and loricrin protein. Dermis deterioration was evaluated by transmission electronic microscopy and zymography in situ. RESULTS: We were able to observe and quantify deleterious effects associated with UVA irradiation: epidermal and dermal disruption, appearance of Sunburn cells, increased DNA damage and induced apoptosis. The use of this model in the evaluation of protective compounds was first confirmed using sunscreens, then further validated with a panel of active ingredients which showed beneficial effects on epidermis morphology and DNA integrity after UVA exposure. CONCLUSION: We have developed a model and a standardized protocol, based on the use of human skin explants, which allows us to explore the protective effect of active ingredients to environmental stresses such as UVA.

OBJECTIFS: La fonction principale de la peau est de protéger le corps des agressions externes. Au cours du temps, le vieillissement naturel de la peau est accéléré par des stress externes comme la cigarette, la pollution, les produits chimiques et les radiations solaires. Le rayonnement ultraviolet, en particulier les UVA, cause des dommages de l'ADN, l'apoptose et des modifications morphologiques qui sont responsables du vieillissement prématuré et de cancers. Le but de cette étude est d'établir un modèle cutané reproductible et discriminatoire pour évaluer les dommages créé par les UVA et tester l'efficacité de potentiels produits protecteurs. MÉTHODES: Ce modèle cutané est basé sur un explant de peau humaine irradié aux UVA. Les effets délétères sur l'épiderme sont observés et quantifiés par coloration Hématoxyline-éosine et par des immunofluorescence des protéines É£-H2Ax, cytokératine 5, involucrine et loricrine. Le détérioration du derme est évaluée par microscopie électronique à transmission et par zymographie in situ. RÉSULTATS: Nous avons observé et quantifié des effets délétères associés aux irradiation UVA: détérioration de l'épiderme et du derme, apparition de cellules "coup de soleil", augmentation des dommages de l'ADN et l'induction de l'apoptose. L'utilisation du modèle pour tester des nouveaux composés a été premièrement validée avec l'utilisation d'un filtre solaire puis validée par le test d'un panel d'ingrédients actifs qui ont montré des effets bénéfiques sur la morphologie de l'épiderme et l'intégrité de l'ADN après exposition aux UVA. CONCLUSION: Nous avons développé un modèle et un protocole standardisé basé sur l'utilisation d'un explant de peau humaine qui permet d'explorer l'effet protecteur ingrédients actifs contre des stress environnementaux comme les UVA.

Development and validation of a new tool to assess the Burden of Sensitive Skin (BoSS).

BACKGROUND: Sensitive skin usually manifests itself as unpleasant sensations and sometimes erythema. There are various triggering factors for this condition. Although sensitive skin may alter quality of life, its burden has not yet been explored. OBJECTIVE: The aim of this study was to develop and validate a specific sensitive skin burden questionnaire called the BoSS (Burden of Sensitive Skin). METHODS: A conceptual phase was developed, followed by a development phase, external validation, psychometric analysis, test-retest analysis and, finally, a translation, cross-cultural adaptation and cognitive debriefing. RESULTS: A total of 6471 individuals participated in the study (4614 people in the validation study). The dimensionality of items was evaluated using factor analyses, suggesting three dimensions (self-care, daily life and appearance). Unidimensionality was confirmed by higher order factor analysis. The overall Cronbach's α coefficient was high, and intradimensional coherences all demonstrated good reliability. The final instrument consisted of 14 items. The test-retest reliability demonstrated very good reproducibility. The intraclass correlation of each dimension was high. External validity was confirmed by the correlation coefficients of the BoSS vs. those of the SF-12 and the DLQI assessment tools. CONCLUSION: BoSS is the first reliable tool to assess the burden of sensitive skin.

3D imaging of cleared human skin biopsies using light-sheet microscopy: A new way to visualize in-depth skin structure.

BACKGROUND: Human skin is composed of the superimposition of tissue layers of various thicknesses and components. Histological staining of skin sections is the benchmark approach to analyse the organization and integrity of human skin biopsies; however, this approach does not allow 3D tissue visualization. Alternatively, confocal or two-photon microscopy is an effective approach to perform fluorescent-based 3D imaging. However, owing to light scattering, these methods display limited light penetration in depth. The objectives of this study were therefore to combine optical clearing and light-sheet fluorescence microscopy (LSFM) to perform in-depth optical sectioning of 5 mm-thick human skin biopsies and generate 3D images of entire human skin biopsies. MATERIALS AND METHODS: A benzyl alcohol and benzyl benzoate solution was used to successfully optically clear entire formalin fixed human skin biopsies, making them transparent. In-depth optical sectioning was performed with LSFM on the basis of tissue-autofluorescence observations. 3D image analysis of optical sections generated with LSFM was performed by using the Amira® software. RESULTS: This new approach allowed us to observe in situ the different layers and compartments of human skin, such as the stratum corneum, the dermis and epidermal appendages. With this approach, we easily performed 3D reconstruction to visualise an entire human skin biopsy. Finally, we demonstrated that this method is useful to visualise and quantify histological anomalies, such as epidermal hyperplasia. CONCLUSION: The combination of optical clearing and LSFM has new applications in dermatology and dermatological research by allowing 3D visualization and analysis of whole human skin biopsies.

Primary cutaneous phaeohyphomycosis. Report of three cases.

Dematiaceous fungi have a diverse clinical spectrum that presents a difficult problem in diagnosis and treatment. These opportunistic pathogens are of concern in healthy, debilitated, or immunocompromised individuals. We describe three patients with localized cutaneous infections produced by dematiaceous filamentous fungal organisms with varying clinical presentations. Two patients were immunocompromised, and a third was otherwise healthy. The unusual clinical and unique histologic features of these difficult infections are reported in detail, as is their successful medical management with ketoconazole (Nizoral) and an experimental antifungal agent, fluconazole.

Epidemiologic studies among Amerindian populations of Amazonia. III. Intestinal parasitoses in newly contacted and acculturating villages.

The prevalences of intestinal parasites among the residents of three South American Indian villages in the process of acculturation were compared with those found in earlier unpublished surveys in two newly contracted village.s Although one individual in an acculturating village harbored 11 different intestinal parasites, in general the average number of different parasitic species carried per person was somewhat higher in the newly contacted villages. Helminth egg counts, performed on direct smears of each specimen from one newly contacted village, were low. There were no sex-associated differences in prevalences. The overall prevalences, unadjusted for age, were among the highest recorded for Amerindians. No Taenia species were present. Balantidium coli was present in two acculturating villages, concomitant with the beginning of agricultural practices which include raising swine. No cases of moderate or severe protein-calorie malnutrition was observed in any of the villages during the surveys. These limited data provide a baseline for future comparisons and, perhaps, a glimpse into the past.