The aim of this study was to evaluate the influence of the depth of the dermis on the measured collagen and elastin levels and to establish the correlation between the amount of these two extracellular matrix (ECM) components and age. Multiphoton Microscopy (MPM) that measures the autofluorescence (AF) and second harmonic generation (SHG) was used to quantify the levels of elastin and collagen and to determine the SAAID (SHG-to-AF Aging Index of Dermis) at two different skin depths. A 50 MHz ultrasound scanner was used for the calculation of the Sub Epidermal Non Echogenic Band (SENEB). The measurements of the skin mechanical properties were done with a cutometer. All measurements were performed on two groups of 30 healthy female volunteers. The MPM showed a decrease of the quantity of collagen and elastin as a function of depth of the dermis as well as age. The SAAID was lower for the older skin in the deeper dermis. Ultrasound imaging revealed a significant decrease of SENEB as a function of aging. The mechanical properties confirmed a loss of cutaneous elasticity and firmness. Although multiphoton microscopy is a powerful technique to study the characteristics of the dermis and its age-related damage, the location of the measurements (depth) remains very

Canities (or hair greying) is an age-linked loss of the natural pigment called melanin from hair. While the specific cause(s) underlying the loss of melanogenically-active melanocytes from the anagen hair bulbs of affected human scalp remains unclear, oxidative stress sensing appears to be a key factor involved. In this study, we examined the follicular melanin unit in variably pigmented follicles from the aging human scalp of healthy individuals (22–70 years). Over 20 markers were selected within the following categories: melanocyte-specific, apoptosis, cell cycle, DNA repair/damage, senescence and oxidative stress. As expected, a reduction in melanocyte-specific markers in proportion to the extent of canities was observed. A major finding of our study was the intense and highly specific nuclear expression of Ataxia Telangiectasia Mutated (ATM) protein within melanocytes in anagen hair follicle bulbs. ATM is a serine/threonine protein kinase that is recruited and activated by DNA double-strand breaks and functions as an important sensor of reactive oxygen species (ROS) in human cells. The incidence and expression level of ATM correlated with pigmentary status in canities-affected hair follicles. Moreover, increased staining of the redox-associated markers 8-OHdG, GADD45 and GP-1 were also detected within isolated bulbar melanocytes, although this change was not clearly associated with donor age or canities extent. Surprisingly, we were unable to detect any specific change in the expression of other markers of oxidative stress, senescence or DNA damage/repair in the canities-affected melanocytes compared to surrounding bulbar keratinocytes. By contrast, several markers showed distinct expression of markers for oxidative stress and apoptosis/differentiation in the inner root sheath (IRS) as well as other parts of the hair follicle. Using our in vitro model of primary human scalp hair follicle melanocytes, we showed that ATM expression increased after incubation with the pro-oxidant hydrogen peroxide (H2O2). In addition, this ATM increase was prevented by pre-incubation of cells with antioxidants. The relationship between ATM and redox stress sensing was further evidenced as we observed that the inhibition of ATM expression by chemical inhibition promoted the loss of melanocyte viability induced by oxidative stress. Taken together these new findings illustrate the key role of ATM in the protection of human hair follicle melanocytes from oxidative stress/damage within the human scalp hair bulb. In conclusion, these results highlight the remarkable complexity and role of redox sensing in the status of human hair follicle growth, differentiation and pigmentation.

tion in the epidermis on a well established theory, Fick's law of diffusion. A mathematical model was developed to fit the water profile curve for a robust and automated detection of the stratum corneum border. In addition, the new model automatically resulted in an accurately determined slope of the water concentration curve in the stratum corneum. This slope, or more exactly the gradient, is one of two parameters directly related to transepidermal water transport across the stratum corneum.

IFSCC Magazine, 11 (2008) (1) 21-29 Proteoglycans take an important part in tissue homeostasis. In the skin, Proteoglycans are present in the extracellular matrix of dermis, particularly with lumican which plays an important role in dermal homeostasis. In the epidermis, several small proteoglycans such as the syndecans are synthesized and play an important role in keratinocyte activation. There is much data on the alteration during skin aging of the synthesis and structure of glycosaminoglycans and some proteoglycans but little information on small proteoglycans, in particular lumican and syndecan-1.We recently observed a decrease in the synthesis of these two small proteoglycans with aging. We confirm in this work the decrease in lumican in dermis and syndecan-1 in epidermis with aging. These proteoglycans represent original important targets for cosmetology in the fight against skin aging. In different in vitro models, two synthetic acetyl tetrapeptides, AcTP1 and AcTP2, stimulate the synthesis of lumican and syndecan-1, respectively. The beneficial action of AcTP1 on skin thickness and firmness and of AcTP2 on epidermal cohesion has been confirmed in vivo. IFSCC Magazine, 11 (2008) (1) 31-34 A water-in-powder cosmetic is one in which a large amount of water is encapsulated in a powder. In this study we describe the development of this type of cosmetic. We first focused on the hydrophilic/hydrophobic balance of the nano-sized powder surface. We looked at surface state of powders in the gas adsorption test and discovered functional powders that have an optimized balance of hydrorepellency and hydrophilicity due to fractal surface and free hydroxyl groups, respectively. Using this material we created a new powder technology that can encapsulate a large quantity of water in a stable structure. We also looked at how the powders encapsulated water by observing them with wet-SEM and how the encapsulated water is stabilized by measuring the water mobility with 17O-NMR. Based on these result, we developed a new technology with water and powder. By encapsulating a large amount of water, we achieved a cosmetic with many unique characteristics: The powder cosmetic can become a liquid by application of friction on skin, it is convenient to use and provides moist, cool feel. It also functions as an excellent makeup by spreading smoothly on skin to form a uniform makeup coating.

We have demonstrated that plant extracts can relieve the deleterious effects of glycation on human skin. Moreover, a plant extract rich in antioxidant molecules has also significantly preserved the human skin from glycoxidation attacks.