There exists remarkable skin capacitance and TEWL gradients within short distances on selected areas of the face. These gradients are distinctive in the different ethnic groups. In contrast to other reports, we found that darkly pigmented skin does not always have a superior barrier function and differences in skin hydration values are complex on the different parts of the face among the different ethnic groups.

Background: An accurate way to determine skin pigmentation is to acquire the spec-

Background/purpose: The dermal-epidermal junction (DEJ) forms epidermal protrusions down into the dermis (rete ridges) and dermal projections up into the epidermis (dermal papillae). Usually visualized in two-dimensions (2D), our knowledge of how the DEJ changes with ageing is limited. We aimed to characterize how this structure exists in 3D and changes with age. Methods: Photoprotected and photoexposed skin were imaged using reflectance confocal microscopy (RCM) in young and aged individuals. Biopsies of the imaged areas were processed for histological sectioning and for imaging using microcomputed X-ray tomography (microCT). Results: Images obtained from RCM and microCT were used to 3D reconstruct the DEJ. DEJ heights obtained from microCT images showed strong correlation with histology-measured heights. We proposed a novel definition of rete ridges (RR m ) and dermal papillae (DP m ), which allowed easier automated measurement of reduced DP m and RR m volumes in aged skin from microCT reconstructions. An algorithm to map DP m connectivity showed reduced lengths of DP m branches with age.

Background: Facial wrinkles, pores, and uneven skin tone are major beauty concerns. There is differential manifestation of aging signs in different ethnic groups. In this regard, studies on Black Africans from the African continent are scarce.Objective: To investigate facial wrinkles, pores, and skin tone in Black African women from Mauritius Island and elucidate the differences to Caucasian women from France.Methods: Facial images were taken using the imaging system ColorFace ® . Wrinkles and pores were measured by their length, depth, surface, volume, and number; for skin tone, we measured L*a*b* and calculated ITA, IWA Newtone , and color homogeneity. Results:We found good correlations of wrinkle and pore scores with expert ranking done on ColorFace ® images for Caucasians (Spearman's rho = 0.78 and 0.72) andBlack Africans (Spearman's rho = 0.86 and 0.65). Caucasians showed more advanced facial signs of aging than Black Africans. Exceptions were vertical lines on upper lip and the depth of pores which were greatest for the Black African subjects. Black Africans had higher heterogeneity scores indicative for uneven skin tone. Luminance (L*) was significantly higher in Caucasians but a* and b* values were significantly higher in the Black African subjects. ITA and IWA Newtone were significantly higher for Caucasians. Conclusions:The high correlation between expert ranking and wrinkle and pore measurements prove ColorFace ® a valid imaging system to study skin aging. Our results show that Africans from the African continent show delayed signs of aging compared to Caucasians. Some exceptions suggest that ethnic differences in facial aging are a complex phenomenon. K E Y W O R D Santi-aging, Black African skin, Caucasian skin, ColorFace®, Ethnic, facial imaging, pores, skin tone, wrinkles

The determination of local components in human skin from in-vivo spectral reflectance measurements is crucial for medical applications, especially for aiding the diagnostic of skin diseases. Hyper-spectral imaging is a convenient technique since one spectrum is acquired in each pixel of the image, and by inverting a light scattering model, we can retrieve the concentrations of skin components in each pixel. The good performance of the method presented in this paper comes from both the imaging system and the model. The hyper-spectral camera that we conceived uses polarizing filters in order to remove gloss effects generated by the stratum corneum; it provides a high resolution image (1120 × 900 pixels), with a thin spectral sampling of 10 nm over the visible spectrum. The acquisition time of 2 seconds is short enough to prevent movement effects of the imaged area, which is usually the main issue in hyperspectral imaging. The model relies on a two-layer model for the skin, and the Kubelka-Munk theory with Saunderson correction for the light reflection. An optimization method enables computing, in less than one hour, several skin parameters in each of the million of pixels. These parameters (blood, melanin and bilirubin volume fractions, oxygen saturation…) are then displayed under the form of density images. Different skin structures, such as veins, blood capillaries, hematoma or pigmented spots, can be highlighted. The deviation between the measured spectrum and the one computed from the fitted parameters is evaluated in each pixel.

Background Hyperspectral imaging for in vivo human skin study has shown great potential by providing non‐invasive measurement from which information usually invisible to the human eye can be revealed. In particular, maps of skin parameters including oxygen rate, blood volume fraction, and melanin concentration can be estimated from a hyperspectral image by using an optical model and an optimization algorithm. These applications, relying on hyperspectral images acquired with a high‐resolution camera especially dedicated to skin measurement, have yielded promising results. However, the data analysis process is relatively expensive in terms of computation cost, with calculation of full‐face skin property maps requiring up to 5 hours for 3‐megapixels hyperspectral images. Such a computation time prevents punctual previewing and quality assessment of the maps immediately after acquisition. Methods To address this issue, we have implemented a neural network that models the optimization‐based analysis algorithm. This neural network has been trained on a set of hyperspectral images, acquired from 204 patients and their corresponding skin parameter maps, which were calculated by optimization. Results The neural network is able to generate skin parameter maps that are visually very faithful to the reference maps much more quickly than the optimization‐based algorithm, with computation times as short as 2 seconds for a 3‐megapixel image representing a full face and 0.5 seconds for a 1‐megapixel image representing a smaller area of skin. The average deviation calculated on selected areas shows the network's promising generalization ability, even on wide‐field full‐face images. Conclusion Currently, the network is adequate for preview purposes, providing relatively accurate results in a few seconds.

OBJECTIVE: There are methods to evaluate skin colour on defined areas over the face but no approach automatically and accurately evaluates skin colour variations on large facial areas, comparing subjects, treatments and/or time points. We propose such an image-based approach to visualize quickly the outcome of clinical studies on colour variations. METHODS: Among 54 Asian women, one group applied a vehicle twice daily, during 28 days, and the other group an anti-ageing emulsion, taking facial images at baseline and after treatment. Changes in L*a*b* values were studied on four pre-selected facial regions. We also reconstructed average facial images from which the L*a*b* parameters were extracted for every pixel, computing relevance (DE) and significance data. Using colour gradients, we mapped these results onto the average facial images. RESULTS: After treatment, L*a*b* parameters show no statistically relevant colour changes in the vehicle group. In the 'active' group, skin was lighter at the upper cheek and, overall, redness decreased. Relevance and significance maps confirmed no visible colour changes in the vehicle group. In the 'active' group, the mapping approach revealed colour changes and their location. Skin became lighter below the eye, cheek and forehead. It was less red below the eyes, on the cheek, jawline and forehead, and generally more yellow. CONCLUSION: Our image-based mapping approach proves to be powerful. It enables us to identify precise facial regions of relevant and statistically significant colour changes after a topical treatment, regions that would have otherwise been undetected. R esum e OBJECTIF: Il existe des m ethodes pour evaluer la couleur de la peau sur des zones pr e-d efinies du visage mais aucune approche n' evalue de mani ere automatique et pr ecise les variations de couleur de peaux sur de large r egions du visage, en comparant les sujets, les traitements et/ou les temps d'analyse. Nous proposons une telle m ethode bas ee sur l'analyse d'images pour visualiser de mani ere rapide les r esultats des etudes cliniques portant sur des variations colorim etriques. M ETHODES: Parmi 54 femmes d'origine asiatique, un premier groupe a appliqu e un v ehicule deux fois par jour, pendant 28 jours. Un deuxi eme groupe a, lui, appliqu e une emulsion anti-âge. Des images de visage ont et e r ealis ees avant et apr es traitement. Les variations des valeurs L*a*b* ont et e etudi ees sur quatre r egions du visage pr e-s electionn ees. Nous avons egalement reconstruit des images de visages moyens pour lesquelles les param etres L*a*b* ont et e extraits pour chaque pixel. Pour ces mêmes pixels, les valeurs de pertinence (delta E) et significativit e ont et e calcul ees. A l'aide d'un gradient de couleur, nous avons repr esent e ces r esultats sur les images de visages moyens. RESULTATS: Apr es traitement, les param etres L*a*b* n'ont montr e aucun r esultat significativement pertinent pour le groupe ayant appliqu e le v ehicule. Pour le groupe "actif", la peau est devenue plus claire sur la part...

Aging of skin manifests in loss of volume and firming due to degradation of extracellular matrix components such as collagen and hyaluronic acid leading to wrinkling and sagging. To counteract loss of facial volume and regain firmness, fillers like hyaluronic acid (HA) are commonplace in cosmetic dermatology. We developed a synthetic tripeptide tetradecyl aminobutyroylvalylaminobutyric acid urea trifluoroacetate with proven hyaluronic acid stimulating activity in vitro. This study investigated the filling and firming activity of the tripeptide. In vitro: Microtissue technology was used to construct spherical 3D-skin equivalents. These were exposed to a tripeptide solution and content of hyaluronic acid and its receptor CD44 were assessed using histological techniques. Skin tissue culture was used to assess HA expression ex vivo. A placebo controlled, randomized, in parallel groups study to assess the firming, filling, and moisturizing activity of the peptide product was designed. We recruited 30 female Caucasian volunteers age 40 to 60 per group. Product application was twice daily for 29 days. Skin volume, deformation and moisturization were measured. HA and CD44 content in skin were increased in vitro and ex vivo. In vivo, skin firming was improved by a significant decrease in cheek deformation, a significantly restored skin volume below the eyes, and significantly improved skin hydration as measured on the cheekbone. We show evidence that the tripeptide tetradecyl-diaminobutyroylvalyldiaminobutyric urea trifluoroacetate restores facial skin volume by stimulating HA synthesis. These results underline the anti-aging activity of this synthetic tripeptide.