Christiane Bertin

Influence of facial skin attributes on the perceived age of Caucasian women

Background and objective  The facial appearance of a person does not always reflect the chronological age; some people look younger or older than they really are. Many studies have described the changes in skin properties (colour, wrinkles, sagging, micro relief, etc.) with age, but few of them have analysed their influence on the perceived age. The primary objective of this study was to assess the contribution of individual skin attributes of the face on the perceived age of Caucasian women. Secondary objectives were to assess the influence of age and gender of graders with regard to the age perception.

Antiaging Action of Retinol: From Molecular to Clinical

The antiaging efficacy of retinol (ROL) has been explored mainly clinically in photoprotected skin sites and for high doses of ROL (0.4–1.6%). The objective of the study was to demonstrate the antiaging action of a low and tolerable dose of ROL (0.1%) ex vivo by measuring the expression of cellular retinoic-acid-binding protein II (CRABP2) and heparin-binding epidermal growth factor (HBEGF) by a histological evaluation of the epidermis and in vivo by assessing major aging signs and performing three-dimensional profilometry and digital imaging during a 9-month double-blind placebo-controlled study involving 48 volunteers. Finally, epidermal cell proliferation was evaluated using tryptophan fluorescence spectroscopy. Our results demonstrate that 0.1% ROL induced CRABP2 and HBEGF gene expression and increased keratinocyte proliferation and epidermal thickness. In human volunteers, topical application of a ROL-containing product improved all major aging signs assessed in our study (wrinkles under the eyes, fine lines and tone evenness). Moreover, tryptophan fluorescence increased in the active-agent-treated group and not in the placebo-treated group, indicating that cell proliferation was accelerated in vivo. These data demonstrate that a product containing a low dose (0.1%) of ROL promotes keratinocyte proliferation ex vivo and in vivo, induces epidermal thickening ex vivo and alleviates skin aging signs, without any significant adverse reaction.

Standardized Diaper Care Regimen: A Prospective, Randomized Pilot Study on Skin Barrier Function and Epidermal IL‐1α in Newborns

Abstract:  Adaptation of skin barrier function and interleukin‐1α (IL‐1α) content in diapered and nondiapered skin are poorly characterized in newborns receiving standard skin care. In a monocentric, prospective pilot study 44 healthy, full‐term neonates were randomly assigned to skin care with baby wipes (n = 21) or water‐moistened washcloth (n = 23) at each diaper change. Transepidermal water loss (TEWL), skin hydration, skin‐pH, IL‐1α, and epidermal desquamation were measured on days 2, 14, and 28 postpartum. Microbiological colonization was evaluated at baseline and on day 28. Significantly lower TEWL was found on the buttock in the group using baby wipes compared to water. IL‐1α and skin hydration significantly increased and pH decreased independent of skin care regimen. IL‐1α was significantly higher in diapered skin compared to nondiapered skin. Although skin care with wipes seems to stabilize TEWL better than using water, the skin condition and microbiological colonization were comparable using both cleansing procedures. Increase of epidermal IL‐1α may reflect postnatal skin barrier maturation. These data suggest that neither of the two cleansing procedures harms skin barrier maturation within the first four weeks postpartum. Longer observations on larger populations could provide more insight into postnatal skin barrier maturation.

Evaluation of the efficacy of a topical cosmetic slimming product combining tetrahydroxypropyl ethylenediamine, caffeine, carnitine, forskolin and retinol, In vitro, ex vivo and in vivo studies

Three studies were performed to investigate the mechanism of action and evaluate the efficacy of a topical cosmetic slimming product combining tetrahydroxypropyl ethylenediamine, caffeine, carnitine, forskolin and retinol. The Ex vivo study on skin explants showed that caffeine and forskolin both stimulated glycerol release and demonstrates for the first time that retinol and carnitine in combination synergistically stimulated keratinocyte proliferation, which leads to an increase epidermal thickness. The double‐blind, randomized, placebo‐controlled clinical study associating circumference measurements on five selected parts of the body, cutaneous hydration measurements as well as blinded expert grading of skin aspect was conducted on 78 women who applied the product or placebo twice daily for 12 consecutive weeks. After 4 weeks of twice‐daily application of the product, significant reductions in circumference of abdomen, hips–buttocks and waist were already observed. Improvements concerned all the measured body parts after 12 weeks. Orange peel and stubborn cellulite decreased significantly from 4 weeks of treatment and tonicity improved from 8 weeks, demonstrating that the product improved skin aspect. At the end of the study, eight parameters of the thirteen evaluated were significantly improved in the active group and compared with placebo.

The revised COLIPA in vitro UVA method.

A multicentred study derived from the COLIPA in vitro UVA method was performed to assess the influence of test conditions on UVA protection factor (UVAPF) values in terms of amplitude, reproducibility between laboratories and correlation with in vivo UVA results. Eight products with a range of in vivo UVAPF from three to 29 were used. Two different types of plates, namely high‐roughness (5 μm) and low‐roughness (2 μm) plates, were used with a different application rate for each (1.3 mg cm−2 and 0.75 mg cm−2 respectively). The UVR dose applied to both plate types followed the same principle as the original test (1.2 J. cm−2 × UVAPF0). Strong, significant correlations between in vitro and in vivo UVAPF values were observed for both plate types (Pearson correlation > 0.9, P ≤ 0.01). The correlation and slope obtained with the low‐roughness plates confirmed the previous results obtained by COLIPA. Across all laboratories, higher UVAPF values were obtained on the high‐roughness plates (P < 0.01). Reproducibility of UVAPF values between laboratories was comparable between the two plate roughness values (low roughness, COV = 8%; high roughness, COV = 12%). Considering the in vitro/in vivo comparisons, a regression slope of 0.83 was observed for the low‐roughness plates, in comparison with a value of 1.05 for the high‐roughness plates. The accuracy of the method was improved, therefore, with the use of the high‐roughness plates. With a constraint to recommend the use of only one plate type in the COLIPA UVA in vitro Test, the high‐roughness plate was selected on an on‐going basis to limit variability of results and to provide better accuracy with in vivo data.

Effect of Aging on DNA Excision/Synthesis Repair Capacities of Human Skin Fibroblasts

TO THE EDITOR A key factor in the skin aging process is the cumulative effects of chronological aging and environmental-based assaults. Endogenous cellular oxidative processes generate reactive oxygen species and reactive polyunsaturated fatty acid derivatives (Lindahl, 1993; Marnett and Plastaras, 2001). These attacks on DNA cause substantial base and sugar damage, and the persistence of such lesions leads to mutations and genome instability. Skin may also suffer from chronic exposure to sun; UV radiation causes oxidative DNA damage and induces photoproducts (mainly cyclobutane pyrimidine dimers and 6-4 photoproducts (Moriwaki and Takahashi, 2008)). Age-related accumulation of somatic damage can thus be worsened by sun exposure, leading to an increased incidence of skin disorders and dramatic acceleration of skin aging (Niedernhofer, 2008). Mammalian cells have evolved several DNA-repair pathways to remove all the categories of DNA base lesions, relying in particular on DNA excision mechanisms. One of these, nucleotide excision repair, removes bulky adducts and is thus an essential mechanism for correcting UV-induced DNA damage (Sarasin, 1999). The base excision repair pathway corrects small base modifications such as oxidized and alkylated bases (Almeida and Sobol, 2007). The importance of repair mechanisms is demonstrated by the hazardous consequences of genetic defects in DNA repair (Friedberg, 2001), but investigating DNA repair with respect to aging remains a challenge. This is due to the complexity of the underlying repair mechanisms as well as to the varying approaches in terms of assays and end points measured (Vijg, 2008). To better understand the relationship between aging and DNA repair, we took advantage of our newly developed multiplexed excision/synthesis assay (Millau et al., 2008) to examine simultaneously, using nuclear extracts, the base excision repair and nucleotide excision repair capacities of human primary fibroblasts derived from healthy donors of different ages. In addition, we investigated changes in DNA repair attributed to chronic sun exposure. A total of 33 healthy Caucasian women were recruited by the Dermscan Group (Lyon, France). Biopsy removal was performed in accordance with the Declaration of Helsinki Principles Guidelines after approval for the study had been given by a medical ethics committee and written consent obtained from the donors. The volunteers were classified into three groups by age (group 1: mean age1⁄425 years, range 20–33, n1⁄49; group 2: mean age1⁄446 years, range 40–50, n1⁄4 9; group 3: mean age1⁄4 65 years, range 61–68, n1⁄415). All subjects were nonsmokers, had phototype II or III skin, declared no excessive exposure to sun or UVA, had no cutaneous pathology, and were not receiving medical treatment. Fibroblast cultures were established from outgrowth of two 3 mm punches taken on the volar forearm (photoexposed area) and the upper inner arm (photoprotected area). Cells were harvested during the exponential phase of growth and stored frozen in liquid nitrogen at passage 5. Nuclear extracts were prepared as described by Millau et al. (2008). For each sample, excision/ synthesis repair reactions were run for 2.5 hours at 30 1C at a final protein concentration of 0.15 mg ml , along with 1 mM adenosine triphosphate and 1.25 mM dCTP-Cy5 (Amersham, Little Chalfont, England), on damaged plasmid microarrays prepared as described by Millau et al. (2008) (see Supplementary Data and Supplementary Figures online for experimental details and nuclear extract features). The microarrays were prepared using Hydrogel slides (Perkin Elmer, Courtaboeuf, France) spotted with unmodified control plasmids together with five plasmid families containing serial amounts of typical lesions (three dilutions per plasmid family). Lesions present on the support were formed by specific physical and chemical treatments: photoproducts (cyclobutane pyrimidine dimers and (6–4)photoproducts), 8-oxoguanine, alkylated bases, abasic sites, and pyrimidine glycols. Total fluorescence intensity related to the fluorescence incorporated into plasmids was the parameter used for calculations (Genepix 4200A scanner, Axon GenePix, Molecular Devices, Sunnyvale, CA). A total fluorescence intensity value was calculated for each lesion type by adding the values for the corresponding replicates. Hence, each microarray generated one value per lesion type. The mean of the two values obtained per sample and per lesion type were used for statistical purposes. Assessment of the mean fluorescence intensity (shown with the corresponding standard error for each lesion type in Figure 1) revealed a decrease in excision/ synthesis activity with age, irrespective of the repair pathway considered. Statistical analysis (general linear model (Minitab V14 software, The MathWorks, Natick, MA) was performed on these latter data from 31 samples: photoprotected and photoexposed cells from the same subject. The general linear model was used to estimate the influence of age

Development and validation of a photonumeric grading scale for assessing lip volume and thickness.

Background  Currently, there is the need of a validated grading scale for assessing lip volume/thickness.

Evaluation of the cellulite using a thermal infra‐red camera

Cellulite is usually related to alterations of the microcirculation. Measuring the skin temperature is a mean to assess the skin microvascular plexus.

Combined retinol-lactose-glycolic acid effects on photoaged skin: a double-blind placebo-controlled study.

The objective of this study was to assess the efficacy of the combination of retinol, lactose and glycolic acid applied topically on photodamaged skin. Forty female volunteers were enrolled in a double‐blind, randomized placebo‐controlled clinical study. A cream containing retinol, lactose and glycolic acid was applied on one side of the face and a placebo cream on the other side, twice daily for 12 weeks. Skin photoageing signs were assessed clinically, whereas skin microrelief and moisturization were measured instrumentally. Both the clinical assessment and the objective instrumental measurements revealed that the active‐treated side was significantly improved at the end of the study compared with baseline and control‐treated side. In conclusion, our results demonstrate that topical application of a combination of retinol, lactose and glycolic acid has significantly improved the appearance of photodamaged skin.

Biophysical properties of striae distensae evaluated in vivo using non‐invasive assays

Striae Distensae (SD) or stretch marks are manifestations of epidermal atrophy that occurs after tissue tearing due to rapid growth or over‐stretching and are characterized by distinct microstructural features. The objective of this in vivo study was to investigate the biophysical properties of SD lesions, including skin barrier function, skin surface hydration, mechanical properties, and chromophore concentrations, compared to normal adjacent skin.