Fragility of epidermis and its consequence in dermatology

The skin is the largest organ of the body, providing a protective barrier against bacteria, chemicals and physical insults while maintaining homeostasis in the internal environment. Such a barrier function the skin ensures protection against excessive water loss. The skin's immune defence consists of several facets, including immediate, non-specific mechanisms (innate immunity) and delayed, stimulus-specific responses (adaptive immunity), which contribute to fending off a wide range of potentially invasive microorganisms. This article is an overview of all known data about 'fragile skin'. Fragile skin is defined as skin with lower resistance to aggressions. Fragile skin can be classified into four categories up to its origin: physiological fragile skin (age, location), pathological fragile skin (acute and chronic), circumstantial fragile skin (due to environmental extrinsic factors or intrinsic factors such as stress) and iatrogenic fragile skin. This article includes the epidemiologic data, pathologic description of fragile skin with pathophysiological bases (mechanical and immunological role of skin barrier) and clinical description of fragile skin in atopic dermatitis, in acne, in rosacea, in psoriasis, in contact dermatitis and other dermatologic pathologies. This article includes also clinical cases and differential diagnosis of fragile skin (reactive skin) in face in adult population. In conclusion, fragile skin is very frequent worldwide and its prevalence varies between 25% and 52% in Caucasian, African and Asian population. © 2014 European Academy of Dermatology and Venereology

Results from in vitro and ex vivo skin aging models assessing the antiglycation and anti-elastase MMP-12 potential of glycylglycine oleamide

Patrick Bogdanowicz, Marie-José Haure, Isabelle Ceruti, Sandrine Bessou-Touya, Nathalie Castex-Rizzi Department of Pharmacology, Pierre Fabre Dermo-Cosmétique, Toulouse, France Background: Glycation is an aging reaction of naturally occurring sugars with dermal proteins. Type I collagen and elastin are most affected by glycation during intrinsic chronological aging. Aim: To study the in vitro and ex vivo assays in human skin cells and explants and the antiaging effects of glycylglycine oleamide (GGO). Materials and methods: The antiglycation effect of GGO was assessed in a noncellular in vitro study on collagen and, ex vivo, by immunohistochemical staining on human skin explants (elastin network glycation). The ability of GGO to contract fibroblasts was assessed in a functional assay, and its anti-elastase (MMP-12) activity was compared to that of oleic acid alone, glycylglycine (GG) alone, and oleic acid associated with GG. Results: In vitro, GGO reduced the glycation of type I collagen. Ex vivo, GGO restored the expression of fibrillin-1 inhibited by glycation. Furthermore, GGO induced a tissue retraction of almost 30%. Moreover, the MMP-12 activity was inhibited by up to 60%. Conclusion: Under the present in vitro and ex vivo conditions, GGO prevents glycation of the major structural proteins of the dermis, helping to reduce the risk of rigidification. By maintaining the elastic function of the skin, GGO may be a promising sparring partner for other topical antiaging agents. Keywords: extracellular matrix, glycylglycine oleamide, glycation, fibrillin-1, matrix metalloproteinase-12, skin agin

A new hair follicle-derived human epidermal model for the evaluation of sunscreen genoprotection

International audienceInduction of skin cancer is the most deleterious effect of excessive exposure to sunlight. Accurate evaluation of sunscreens to protect the genome is thus of major importance. In particular, the ability. of suncare products to prevent the formation of DNA damage should be evaluated more directly since the Sun Protection Factor is only related to erythema induction. For this purpose, we developed an in vitro approach using a recently characterized reconstituted human epidermis (RHE) model engineered from hair follicle. The relevance of this skin substitute in terms of UV-induced genotoxicity was compared to ex vivo explants exposed to solar-simulated radiation (SSR). The yield of bipyrimidine photoproducts, their rate of repair, and the induction of apoptosis were very similar in both types of skin samples. In order to evaluate the protection afforded by sunscreen against DNA damage, bipyrimidine photoproducts were quantified in tissue models following SSR exposure in the presence or absence of a SPF50+ formula. A rather high DNA protection factor of approximately 20 was found in RHE, very similar to that determined for explants. Thus, RHE is a good surrogate to human skin, and also a convenient and useful tool for investigation of the genoprotection of sunscreens. (C) 2015 Elsevier B.V. All rights reserved

Formulation of a new broad‐spectrum UVB + UVA and blue light SPF50 + sunscreen containing Phenylene Bis‐Diphenyltriazine ( TriAsorB ), an innovative sun filter with unique optical properties

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