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

Androgens activate lipogenesis through an AKT-independent mTOR pathway stimulation and a limitation of autophagy in an androgen-sensitive sebocyte cell line.

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Androgens are key regulators of sebaceous function... A link between mTOR and androgen signaling has previously been reported...as well as a link between these processes and lipid synthesis...Here we aimed at confirming that DHT-induced lipid synthesis/accumulation is at least in part dependent on mTOR activation in the SEBO662AR cell line and that the autophagic process is consequently modified by the androgenic treatment.
in vitro and ex vivo assays: skin protection and immune defense system

Pollution and epigenetics: Histone H3 modifications in keratinocytes after exposure to urban dust and Benzo(a)pyrene

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In this work, human epidermal keratinocytes were used to study the effects of urban dust and benzo(a)pyrene on the epigenetic pattern of the histone H3 protein. The assay was then used to screen a series of plant extracts in order to find cosmetic actives to protect the skin against air pollution.

Pseudomonas aeruginosa flagellum is critical for invasion, cutaneous persistence and induction of inflammatory response of skin epidermis

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Pseudomonas aeruginosa, an opportunistic pathogen involved in skin and lung diseases, possesses numerous virulence factors, including type 2 and 3 secretion systems (T2SS and T3SS) and its flagellum, whose functions remain poorly known during cutaneous infection.

New biological effects of Aphloïol

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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.

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

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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 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)

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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).

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

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

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

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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

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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

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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.