Reduction of wrinkles: From a computational hypothesis to a clinical, instrumental, and biological proof.

BACKGROUND: Facial wrinkles are clear markers of the aging process, being chronological, photo-induced, or reflecting repetitive facial expressions. The aim of this study is to provide new insights into the biophysical and biological mechanisms involved in the formation, prevention, or elimination of the expression wrinkles. MATERIALS AND METHODS: We use a computational model to get a better understanding of the wrinkle mechanical behavior and evolution after skin softening and suggesting a possible antiaging mechanism. Then, we provide a clinical demonstration of the anti-wrinkle effect of a long-term application of a 20% glycerol in a moisturizer formula (GBM) versus its vehicle on crow's feet. Skin hydration, elasticity, and wrinkles visibility were evaluated by a combination of clinical and instrumental in vivo data, inverse finite element analysis, and proteomic data. RESULTS: The computational model shows a predominantly compressive stress beneath the wrinkle and its significant decrease by the softening of stratum corneum. The associated clinical study confirmed a significant increase of skin hydration and elasticity as well as a decrease of wrinkle visibility after 2 and 4 months as application for both formulas; this effect being stronger for GBM. A softening effect on stratum corneum and dermis was also observed for the GBM. Furthermore, proteomic data revealed an effect of upregulation of four proteins associated with desquamation, cell-glycan extracellular interactions, and protein glycation/oxidation, functions related to the tissue mechanics and adhesion. CONCLUSIONS: We provide an in vivo demonstration of the anti-ageing benefit of glycerol at high dose (20%) reflected by a cumulative skin surface softening effect. The use of high moisturizing potent formulations should bring additional performance to other conventional moisturizing formulations.

Differential involvement of glycans in the binding of Staphylococcus epidermidis and Corynebacterium spp. to human sweat.

Sweat is a secretory fluid that can be a source of unpleasant body odour due to interaction of resident bacteria with sweat components. Identification of glycoproteins in sweat suggests that protein-conjugated glycans may act as binding epitopes for bacteria, as found in other secretory fluids such as human milk, tears and saliva which help to protect epithelial surfaces from infection. We conducted proteomic and glycomic analysis of sweat to reveal an abundance of glycoproteins, predominantly carrying bi-antennary sialylated N-glycans with or without fucose. A fluorescent plate assay was used to determine whether glycans on sweat proteins provide binding epitopes for odour-producing skin commensals Staphylococcus epidermidis and Corynebacterium. Sialic acid and fucose were found to be important binding epitopes for S. epidermidis 3-22-BD-6, a strain recently isolated from human sweat, whereas fucose (but not sialic acid) contributed to the binding of Type strain S. epidermidis ATCC 12228. In contrast, our results indicate that sweat N-glycans do not provide binding epitopes for Corynebacterium. Synthetic sugar mimics of Lewis blood group antigens were investigated as potential inhibitors of the binding of S. epidermidis 3-22-BD-6 to sweat. Pre-incubation of the bacterium with LeB, LeX, LeY and sLeX (pentaose) resulted in a significant reduction in sweat protein adhesion indicating that terminal fucose is a key binding epitope, particularly when linked to a Type 2 chain (Galß1-4GlcNAc) configuration (LeY). Our results form an impetus for future studies seeking to elucidate the role of glycans in sweat associated malodour, with possible implications for cosmetic and medical fields.

Skin complexion and pigmentary disorders in facial skin of 1204 women in 4 Indian cities.

BACKGROUND: The color of Indian skin shows great diversity and pigmentary disorders are a major concern of Indian women. Despite great variations in climate, diet, and social parameters within India, studies of the range of skin types have been rather scarce. AIMS: This study was aimed at characterizing the color of Indian skin in various geographical locations, its characteristics in terms of overall skin complexion and pigmentary disorders, and the impact of age on these features. METHODS: An extensive descriptive study, including skin color parameters (objective measurements and evaluations by dermatologists, clinically or from photographs) was carried out involving 1,204 female volunteers of different ages living in four different Indian cities. RESULTS: Important differences in skin complexion according to the geographical location were observed. Age seemed to have little impact on complexion. Hyperpigmented spots were frequent and were noted at early stages and many lentigines were found. Melasma affected about 30% of middle-aged women, but many other ill defined, pigmented macules were also observed. Additionally, we found pigmented lip corners associated with marionette lines, and linear nasal pigmentation. CONCLUSIONS: Indian skin color is diverse and pigmentary disorders are common. Skin complexion is not greatly affected by age. Some hyperpigmented disorders occur at early stages and increase with age, contributing to overall unevenness of facial color.