Ensemble des articles de Bioalternatives traitant de la biologie de la peau ainsi que des modèles cellulaires et tests in vitro d’intérêts pour l’évaluation de l’efficacité des produits et ingrédients cosmétiques

New Biological Activities of Lythrum salicaria L.

The perennial and widespread herb Lythrum salicaria L., also called purple loosestrife, is a plant that is traditionally used in European medicine.
lipid

Effects of different kinds of pollutants on the lipidic metabolism of human sebocytes and protective effects of a new macroalgae culture extract

Sebocytes lipid production are stimulated by pollutants. Ame acts by protecting epidermal cells, human sebocytes and skin from urban dust.

Acné vulgaris : Physiopathologie et mécanismes cellulaires

L’acné vulgaris est une pathologie inflammatoire chronique cutanée localisée au niveau du follicule pilo-sébacé. Elle apparaît suite à une surproduction de sébum liée à des dysfonctionnements d’origine hormonale (androgène), environnementale (pollution…) et à la colonisation du follicule pilo-sébacé par certaines bactéries (P. acnes). (Dans ce contexte), Bioalternatives a développé un panel de tests originaux destinés à la découverte et l’évaluation de composés pour le traitement de l’acné.
glande sébacée

La glande sébacée : Physiologie et fonctions

La glande sébacée est un organe localisé au niveau du derme. Elle est responsable de la synthèse et de la sécrétion du sébum qui entre dans la composition du film hydrolipidique. Le rôle du sébum est de protéger la peau des agressions extérieures et de la déshydratation. Le sébum permet également d’entretenir la souplesse de la peau et des cheveux.
phototoxicity

Le cheveu: follicule, structures associées et croissance

Le follicule pileux est une annexe de la peau qui a la capacité de se renouveler de manière parfaitement autonome, cyclique et asynchrone. L'analyse histologique de l'unité pilo-sébacée révèle une organisation en deux compartiments: le compartiment d'origine épithélial et le compartiment d'origine mésenchymale.

New biological effects of Aphloïol

In the present study, we identified new properties of Aphloïol (syn. mangiferin) in improving skin barrier function, especially by promoting keratinocyte differentiation, synthesis of transmembrane glycoprotein and lipid neosynthesis.
skin photoaging irradiations

in vitro modeling of skin photoaging: development of evaluation tools for cosmetics

Development of in vitro models skin for better understand the modifications during photo-aging induced by repetitive UV exposure.
ageing reconstructed epidermis

Development of a new model of reconstructed aged skin useful to study antiageing effects of cosmetic compounds

The development of new anti-ageing products needs performant in vitro models mimicking morphological changes and physiological modifications appearing during skin ageing. In order to have access to a simple model mimicking the epidermis ageing but in relation with a normal dermis, we have developed a new in vitro model of reconstructed skin comprising an aged epidermis covering a reconstructed dermis built with collagen and normal (young) fibroblasts.

Androgens induce sebaceous differentiation in sebocyte cells expressing a stable functional androgen receptor

In order to study the impact of active androgens in sebocytes, we constructed a stable human sebocyte cell line derived from SEBO662 [17] constitutively expressing a fully functional AR. In these SEBO662 AR+ cells, dihydrotestosterone (DHT) induced AR nuclear translocation and the strong modulation of a set of transcripts (RASD1, GREB1...) known to be androgen-sensitive in other androgenic cells and tissues.

Cystinosin is a melanosomal protein that regulates melanin synthesis

In vitro studies showed that cystinosin was located at melanosomes. CTNS silencing led to a 75% reduction of melanin synthesis that was caused by a degradation of tyrosinase by lysosomal proteases. Our results objectify the pigmentation defect in patients with cystinosis. We also identify the role of CTNS in melanogenesis and add a new gene to the list of the genes involved in the control of skin and hair pigmentation.

Immortalized sebocytes SEBO662 can spontaneously differentiate into a sebaceous-like phenotype when cultured as a 3D epithelium

SEBO662 multilayers spontaneously differentiate into a sebaceous-like structure as shown by the strong polarized expression of the late sebaceous marker EMA, the overexpression of some lipogenic markers and lipid production on the upper side of the epithelium.

Effect of C-xyloside on morphogenesis of the dermal epidermal junction in aged female skin. An ultrastuctural pilot study

These data suggest that topical C-xyloside application in vivo may be efficient in inducing a better dermal-epidermal cohesion when such a junction is deficient, as is the case in photo-aged or chronologically aged skin. Moreover, a statistically significant increase in CD44 expression was noted in the epidermis of C-xyloside-treated compared to the placebo treated skin areas.
Lipolytic

Lipolytic effect of a polyphenolic citrus dry extract of red orange, grapefruit, orange (Sinetrol) in human body fat adipocytes. Mechanism of action by inhibition of cAMP-Phosphodiesterase (PDE)

The present study investigated the lipolytic (break of fat stored) effect of a citrus-based polyphenolic dietary supplement (SINETROL) at human adipocytes (ex vivo), body fat (clinical) and biochemical levels (inhibition of phosphodiesterase).
tensin1

Reduced expression of the adhesion protein tensin1 in cultured human dermal fibroblasts affects collagen gel contraction

tensin1 plays an important role in cell-matrix interaction and that a reduced expression might contribute to the dermal alterations observed during skin ageing
UV-induced

Alternative (non-animal) methods for cosmetic testing: current status and future prospects - UV-induced effects

Cosmetic ingredients and mixtures of ingredients absorbing UV light (in particular UV filter chemicals used, for example, to ensure the light stability of cosmetics or used in sun protection products) should be tested for acute phototoxic and photogenotoxic potential.
acute toxicity

Alternative (non-animal) methods for cosmetic testing: current status and future prospects - Acute toxicity

From the regulatory point of view, the main objective of acute toxicity testing is basically to classify chemicals according to their intrinsic toxicity
gene expression

Comparison of gene expression profiles in human keratinocyte mono-layer cultures, reconstituted epidermis and normal human skin; transcriptional effects of retinoid treatments in reconstituted human epidermis

In order to validate a model for predictive screening of dermatological drugs, we used a customized cDNA macro-array system containing 475 skin-related genes to analyze the gene expression patterns in human keratinocytes from different origins.
phototoxicity

Development of a highly sensitive in vitro phototoxicity assay using the SkinEthic reconstructed human epidermis

The reconstituted human epidermis model SkinEthic was used to evaluate the phototoxicity of topically applied chemicals.