Assessing the Role of Carbonyl Adducts, Particularly Malondialdehyde Adducts, in the Development of Dermis Yellowing Occurring during Skin Photoaging.

Solar elastosis is associated with a diffuse yellow hue of the skin. Photoaging is related to lipid peroxidation leading to the formation of carbonyl groups. Protein carbonylation can occur by addition of reactive aldehydes, such as malondialdehyde (MDA), 4-hydroxy-nonenal (4-HNE), and acrolein.

UVA Exposure Combined with Glycation of the Dermis Are Two Catalysts for Skin Aging and Promotes a Favorable Environment to the Appearance of Elastosis.

Skin aging is the result of superimposed intrinsic (individual) and extrinsic (e.g., UV exposure or nutrition) aging.

Vitamin C prevents epidermal damage induced by PM-associated pollutants and UVA1 combined exposure.

Particulate matter is suspected to be substantially involved in pollution-induced health concerns. In fact, ultrafine particles (UFPs) contain polycyclic aromatic hydrocarbons (PAHs) known as mutagenic, cytotoxic and sometimes phototoxic. Since UFPs reach blood circulation from lung alveoli, deep skin is very likely contaminated by PAHs coming from either skin surface or blood.

Genome-wide profiling of adult human papillary and reticular fibroblasts identifies ACAN, Col XI α1, and PSG1 as general biomarkers of dermis ageing, and KANK4 as an exemplary effector of papillary fibroblast ageing, related to contractility.

Deciphering the characteristics of dermal fibroblasts is critical to further understand skin ageing. We have conducted a genome-wide transcriptomic characterization of papillary (Fp) and reticular (Fr) fibroblasts extracted from human skin samples corresponding to younger and older adult ages. From this screen, biomarkers suitable for the assessment of chronological ageing were identified, and extrapolated to the context of photo-damaged skin.

Biological Effects Induced by Specific Advanced Glycation End Products in the Reconstructed Skin Model of Aging.

Advanced glycation end products (AGEs) accumulate in the aging skin. To understand the biological effects of individual AGEs, skin reconstructed with collagen selectively enriched with N(ɛ)-(carboxymethyl)-lysine (CML), N(ɛ)-(carboxyethyl)-lysine (CEL), methylglyoxal hydroimidazolone (MG-H1), or pentosidine was studied. Immunohistochemistry revealed increased expression of α6 integrin at the dermal epidermal junction by CEL and CML (p<0.

Skin aging by glycation: lessons from the reconstructed skin model.

Background: Aging is the result of several mechanisms which operate simultaneously. Among them, glycation is of particular interest because it is a reaction which affects slowly renewing tissues and macromolecules with elevated half-life, like the dermis, a skin compartment highly affected by aging. Glycation produces crosslinks between macromolecules thereby providing an explanation for the increased age-related stiffness of the skin.

Distinct and complementary roles of papillary and reticular fibroblasts in skin morphogenesis and homeostasis.

To study the biological properties of dermal fibroblast sub-populations, we used a reconstructed skin model with a dermal compartment populated with either papillary or reticular fibroblasts. The histological and immunohistological characterization of these reconstructed skins revealed distinct biological and structural differences, depending on the site-matched fibroblast population incorporated. Epidermal differentiation and maturation was favored and found optimum in the presence of papillary fibroblasts with little effect on ECM, as opposed to reticular fibroblasts, which had a significant positive effect on the production of the ECM molecules of the dermal epidermal junction and the dermis.

Biological effects of simulated ultraviolet daylight: a new approach to investigate daily photoprotection.

Background: The irradiance of standard ultraviolet daylight (UV-DL) is representative of most frequently encountered UV exposure conditions and simulators of UV-DL can now be used to properly investigate the biological effects of a non-extreme UV radiation. One of the characteristics of the simulated UV-DL used in this study is its dUVA to dUVB irradiance ratio, which amounts to 24, instead of close to 10, for the simulated zenithal UV radiation (UV-SSR).

Purpose/methods: The aim of our study was to compare photobiological effects induced, in human skin, by acute and semi-chronic exposure to simulated UV-DL with those induced by UV-SSR.