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


Metrology and sensors as dermo-cosmetic technology opportunities for a change of paradigm

According to the International Bureau of Weights and Measurements, metrology, the study of measurement, is becoming an essential aspect of all industries today in creating value.

Type-1 cytokines regulate MMP-9 production and E-cadherin disruption to promote melanocyte loss in vitiligo

Loss of melanocytes is the pathological hallmark of vitiligo.

Canitie et pigmentation des cheveux

La canitie (grisonnement des cheveux) a un large impact social et cosmétique. Bioalternatives présente ici sa physiopathologie, ses causes sous-jacentes et ses traitements.

Profiling TLR agonist activity in keratinocytes and link to bacteria-induced innate immunity activation

In this study, our goal was first to functionally profile and characterize the response of normal human keratinocytes (NHEK) to microbial patterns (TLR agonists) and IL-1α in parallel. To do so, the effects of multiple TLR agonists and IL-1α were evaluated on the gene expression profile, on signal transduction (NF-ƘB translocation) and also on IL-8 and IL-6 release. Secondly, we also tried to link these responses to those of pathogens of interest in skin microbiota (namely, C. acnes, S. aureus and P. aeruginosa), by evaluating the effect on IL-8 release by NHEK infected with living bacteria from these 3 strains...

Innate immunity activation of sebocyte cells by living bacteria. Evidence of a potential immunosuppressive effect of DHT.

Acne is a skin pathology targeting the pilosebaceous unit…sebum hypersecretion and bacterial infection. We studied the effects of living bacteria on the induction of an innate immune response in a sebocyte cell line.

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

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

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

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 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.

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.

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.

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 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).