Hyaluronic acid detection and relative quantification by mass spectrometry imaging in human skin tissues.

Hyaluronic acid (HA) is a major component of the skin, contributing to tissue hydration and biomechanical properties. As HA content in the skin decreases with age, formulas containing HA are widely used in cosmetics and HA injections in aesthetic procedures to reduce the signs of aging. To prove the beneficial effects of these treatments, efficient quantification of HA levels in the skin is necessary, but remains difficult. A new analytical method has been developed based on matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to quantify HA content in cross sections of human skin explants. A standardized and reproducible chemical entity (3 dimeric motifs or 6-mer) quantifiable by MALDI-MSI was produced by enzymatic hydrolysis using a specific hyaluronidase (H1136) in HA solution. This enzymatic digestion was carried out on skin sections before laser desorption, enabling the detection of HA. Histological coloration allowed us to localize the epidermis and the dermis on skin sections and, by comparison with the MALDI molecular image, to calculate the relative HA concentrations in these tissue areas. Skin explants were treated topically using a formula containing HA or its placebo, and the HA distribution profiles were compared with those obtained from untreated explants. A significant increase in HA was shown in each skin layer following topical application of the formula containing HA versus placebo and untreated samples (average of 126±40% and 92±40%, respectively). The MALDI-MSI technique enabled the quantification and localization of all HA macromolecules (endogenous and exogenous) on skin sections and could be useful for determining the efficacy of new cosmetic products designed to fight the signs of aging.

"You look sleepy " The impact of sleep restriction on skin parameters and facial appearance of 24 women.

BACKGROUND: Total sleep deprivation has a visible impact on subjective facial appearance. However, there is a lack of knowledge on how moderate sleep restriction objectively impairs skin quality and facial aspect. METHODS: Twenty-four healthy good-sleeping women, aged 30-55, volunteered for this study on the impact of sleep restriction (SR) on their facial skin. SR was limited to 3 h per night for 2 consecutive nights. We assessed the following parameters at the same time of day, before and after SR: sebumetry (Sebumeter SM 815), hydration (Corneometer CM 825), trans-epidermal water loss (Tewameter TM 210), biomechanical properties (Cutometer MPA 580), pH (PH-meter 900), desquamation quantification (D-Squameter and microscopy), and image analysis (ColorFace - Newtone Technologies). We also obtained skin samples (swab) for malondialdehyde quantification (MDA). RESULTS: We observed that some skin parameters are significantly associated with SR in both the morning and afternoon, including: lower hydration (p < 0.001), increased trans-epidermal water loss (PIE) (p < 0.001), and decreased extensibility (Uf; p = 0.015) and viscosity (Uv; p < 0.001) of the skin. The average pH increased from 4.8 (±0.2) to 4.9 ± 0.4; p < 0.001. For face photography, brightness and saturation also significantly decreased with SR in mornings and afternoons (p < 0.001 for all tests). Finally, we observed a significant decrease in isolated corneocytes after desquamation associated with SR (p < 0.001 for all tests). SR was also associated with significantly increased MDA levels (p < 0.001 for all tests). CONCLUSIONS: Two nights of SR significantly altered the skin and facial appearances in our test group of typically good-sleeping women.

A photographic scale for the evaluation of facial skin aging in Indian women.

The process of facial skin aging differs between different ethnic populations. Standardized tools to objectively evaluate facial skin aging in clinical and epidemiological studies in different ethnic populations are needed. We designed and validated a photonumeric scale for assessment of facial aging in the Indian population. A total of 149 subjects were selected from an electronic photographic database of 300 women from the Mumbai region. An expert consensus panel selected nine subjects representing a spectrum of skin damage from none to severe, on the basis of wrinkling and tissue slackening. The nine-point scale, composed of one face-on and one oblique photo of the same subject per grade, was validated by nine independent judges in 99 subjects with a repetition two weeks later. Inter-observer reliability and intra-observer reproducibility were calculated using Kappa coefficients. Validation of the scale showed a high level of inter-observer reliability between the consensus and independent panels, and intra-observer reproducibility between the two evaluations performed by the independent judges. In conclusion, this nine-point facial aging scale is a reliable tool for clinical evaluations of skin damage in Indian women, suitable for use in clinical and epidemiological studies.

Age influences the skin reaction pattern to mechanical stress and its repair level through skin care products.

Skin aging is associated with alterations of surface texture, sebum composition and immune response. Mechanical stress induces repair mechanisms, which may be dependent on the age and quality of the skin. The response to mechanical stress in young and aged individuals, their subjective opinion and the objective effectiveness of skin care products were evaluated by biophysical skin quality parameters (stratum corneum hydration, transepidermal water loss, skin pH, pigmentation and erythema) at baseline, 1, 6, 24h and 7days at the forearms of 2 groups of healthy volunteers, younger than 35 years (n=11) and older than 60 years (n=13). In addition, casual surface lipid composition was studied under the same conditions at the baseline and day 7 after mechanical stress induction. Evaluations were also performed in stressed skin areas treated daily with skin care products and the subjective opinion of the volunteers was additionally documented. The tested groups exhibited age-associated baseline skin functions as well as casual surface lipid composition and different reaction patterns to mechanical stress. Skin care was more effective in normalizing skin reaction to stress in the young than in the aged group. The subjective volunteer opinion correlated with the objective measurements.

The use of antisense strategy to modulate human melanogenesis.

BACKGROUND AND OBJECTIVES: Skin without significant dyschromia is an aesthetic goal of people worldwide. Current options for lightening skin could have significant drawbacks. The antisense strategy may be a viable alternative. The reactions in melanogenesis are catalyzed mainly by tyrosinase, tyrosinase-related protein 1 (TRP-1), and TRP-2. Activation of tyrosinase is associated with phosphorylation by protein kinase C-betaI (PKC-betaI) and formation of a complex between phosphorylated tyrosinase and TRP-1. The aim of this study was to use 2 antisense oligonucleotides to modulate the synthesis of the tyrosinase/TRP-1 complex, PKC-beta, or both by interacting with the targeted mRNA, thus whitening skin by interfering with melanogenesis at the translational level. METHODS/STUDY DESIGN: In the in vitro study, the effect of the antisense oligonucleotides was evaluated by measuring the rate at which dihydroxyphenylalanine (DOPA) oxidase transforms L-DOPA to DOPAchrome in the pathway for melanin biosynthesis. A reduction in the reaction rate compared to the controls corresponded to a decrease in the enzyme activity and, consequently, to a reduction of the formation of melanin pigments. To evaluate the in vivo lightening effect of the antisense oligonucleotides, 30 Asian women volunteers with pigmented spots on both hands applied the test product twice daily for 8 weeks. The test product was applied to 2 marked-off areas of the hand: a pigmented spot (to evaluate the effect of the test product on the color of the spot) and a nonpigmented spot area (to evaluate the effect of the test product on normal skin pigmentation). The lightening effect was evaluated by comparing chromametric and mexametric parameters before treatment, after 4 weeks, and after 8 weeks. RESULTS: In vitro DOPA-oxidase activity was inhibited by 13% in melanocytes treated with the antisense sequence for PKC-BI alone, by 16% with the antisense sequence for TRP-1 alone, and by 36% with the association of 2 sequences. The inhibiting effect with both sequences required the specific sequences with nonreversed polarities. In vivo clinical results showed statistically significant whitening in both pigmented spots and nonpigmented spots when the test product was applied twice daily for 8 weeks by up to 30 Asian women. CONCLUSIONS: The association of TRP-1 and PKC-betaI antisense molecules significantly increased the inhibition of tyrosinase activity on human melanocytes. Antisense oligonucleotides are a new generation of active cosmetic ingredients that offer unprecedented specificity, biological stability, and safety in lightening skin. This is the first report of positive results in a cosmetic based on the use of these new active agents.

In vivo skin antioxidant effect of a new combination based on a specific Vitis vinifera shoot extract and a biotechnological extract.

BACKGROUND AND OBJECTIVES: Ultraviolet (UV) light produces reactive oxygen species (ROS) in skin, which accelerate aging by damaging DNA, proteins, lipids, and other cellular constituents. The aims of this study were to 1) evaluate the antioxidant properties of a Vitis vinifera shoot extract on cultured normal human keratinocytes, 2) compare the in vivo antioxidant of this extract in combination with a biotechnological extract (Ronacare Hydroine), and 3) evaluate the efficacy on photoaging skin of a serum based on a combination (Vitis vinifera shoot extract in hydroglycolic solution, or Sarmentine, and Ronacare Hydroine) after a 4-week application, and to quantify the additional improvement given by applying a cream with the serum. METHODS/STUDY DESIGN: An in vitro study was conducted to evaluate the antioxidant properties of Vitis vinifera shoot extract added to cultured normal human keratinocytes. A fluorescent probe was used to quantify cytoplasmic endogenous species formed in response to oxidative stress induced by H2O2. The antioxidant activity of Vitis vinifera shoot extract was compared to that of a solvent control and 2 positive controls, vitamin E and vitamin C. In the first in vivo study, 2 test products were included in a comparative, randomized, single-blind trial in which 27 subjects acted as their own (untreated) controls. Products were applied 4 times to randomized areas of the inner surface of the forearm for one day. The following day, treated and untreated (control) areas of stratum corneum were sampled for fluorimetric analysis. A decrease in fluorescence compared with untreated control reflected a decrease in the level of ROS, in which case the product had a scavenging effect. The 2 products contained a combination of Sarmentine and Ronacare Hydroine, whose antioxidant properties were under investigation. Other products were known antioxidants. In the second in vivo study, 60 female subjects applied either serum or serum plus cream twice daily for 28 days for clinical evaluation. Overall improvement was rated on a quartile scale (0%-25%, 26%-50%, 51%-75%, 76%-100%) and changes in firmness, radiant glow, evenness, smoothness, wrinkles, fine lines, hydration, texture, and softness were rated on a negative to positive scale (-5=worse to +5=greatly improved). RESULTS AND CONCLUSIONS: Vitis vinifera shoot extract appears to have significantly stronger in vitro antioxidant capacity than vitamin C or vitamin E. In the same vehicle (placebo emulsion), ascorbic acid (0.5%), Sarmentine (1%), and the Sarmentine (1%) plus Ronacare Hydroine (1%) combination had a significant in vivo antioxidant effect versus a nontreated area. The combination Sarmentine (1%) plus Ronacare Hydroine (1%) showed a higher efficacy than Sarmentine alone. The dermatologic evaluation showed that a 4-week twice-daily application of a serum containing the combination improved the main clinical signs of photoaged skin. The addition of the cream with the serum appears to enhance the serum-induced improvement of most of the skin characteristics.

Modulation of gene expression as a new skin anti-aging strategy.

BACKGROUND/OBJECTIVES: [corrected] The signs of aging may originate from natural processes or from exposure to the sun, wind, or other environmental factors. To evaluate the anti-aging effects of potential agents researchers must first identify and be able to quantify epidermal markers that change with aging. This paper summarizes the results of studies conducted to evaluate the transcriptional effects of an Aframomum angustifolium seed extract and Malva Sylvestris extract, and the antiaging efficacy of a skin care product containing the Aframomum angustifolium seed extract. METHODS: The transcriptional effect of an Aframomum angustifolium seed extract on normal human keratinocytes (NHKs) and normal human fibroblasts (NHF) was evaluated in vitro with the use of a low-density DNA array technology. The Malva Sylvestris extract was studied with a commercial DNA macroarray and by a real-time quantitative reverse transcriptase-polymerase chain reaction. The in vitro anti-aging activities of the Malva sylvestris extract were compared with those of all-trans retinoic acid (RA), a well-established topical therapy for photodamage and wrinkles. The genes studied were known to be modified by RA. The anti-aging efficacy of a facial skin care product containing Aframomum angustifolium seed extract was evaluated in a single-center study using image processing analysis and in a 2-center study by evaluation of the photographs by the investigator, independent evaluators, and subjects. RESULTS: In general, the Aframomum angustifolium seed extract strongly modified the gene expression profiles of NHKs and weakly modified the gene expression profiles of NHFs. After incubation with Aframomum angustifolium seed extract, the expressions of 3 antioxidant genes (metallothionein 1, metallothionein 2, and thioredoxin) were increased in NHKs, while expressions of 1 antioxidant gene (glutathione peroxidase) was increased in NHFs. Concerning the Malva sylvestris extract, a cDNA macro-array technology experiment with the reconstructed human epidermis model showed that some genes modulated by treatment with the Malva sylvestris extract are also regulated by RA treatment indicating a similar activity at the mRNA level. In the single-center study, a facial skin care product containing the Aframomum angustifolium seed extract significantly improved the homogeneity of the skin. The areas of the detected objects (skin imperfections) decreased significantly on each studied area of the face and the variance decreased significantly over the entire face. In the 2-center study, 28% percent of the subjects reported a greater than 50% overall global improvement in their skin by the end of the study compared to 11% of the subjects after 4 weeks of treatment. Seventy-six percent of subjects said they would purchase the cream. CONCLUSIONS: The authors developed a low-density DNA chip method that permitted the study of the transcriptional effect of Malva Sylvestris extract and of Aframomum angustrifolium seed extract. The gene expression profiles obtained demonstrate the anti-aging properties of these compounds. An in vivo single-center study, performed and analyzed with an assay based on image processing analysis, demonstrated the antiwrinkle activity of a formulation containing the Aframomum angustifolium seed extract. The data obtained in the 2-center study suggests that the cosmeceutical containing Aframomum angustifolium seed extract produces a global rejuvenation effect in terms of redness, pigmentation, and fine lines similar to that noted utilizing an intense pulse light source.

Skin tumours and skin aging in 209 French elderly people: the PROOF study.

Few studies have evaluated the prevalence of skin tumours in the geriatric population and none have analysed different skin aging parameters for whole-body skin in this population. To evaluate the prevalence of skin tumours and global skin aging in a French cohort of elderly people. In total, 209 subjects, 105 women and 104 men (mean age: 77.5; range: 74-81 years), were enrolled from the PROOF (PROgnostic indicator OF cardiovascular and cerebrovascular events) cohort. SCINEXA (SCore for INtrinsic and EXtrinsic skin Aging) was used to assess the degree of skin aging and the prevalence of skin tumours. Some additional cutaneous parameters were also studied. Skin aging in women and men was compared. Mean global SCINEXA was 24.3 (SD: 4.7; range: 8.2-35.3). Solar elastosis and lax appearance were more severe in women (t test; p<0.0001), whereas pseudoscars (t test; p = 0.0312) and coarse wrinkles (t test; p = 0.0479) were more severe in men. Erythrosis coli (chi-square test; p <0.0001) was more frequent in men, whereas varicous veins (chi-square test; p = 0.0026) and eyelid xanthomas (chi-square test; p = 0.0282) were more frequent in women. Twelve patients presented with cutaneous carcinomas and two patients had early melanomas. This research describes in detail the main indices of skin aging in an old population and the differences related to gender. Moreover, it highlights the utility of systematic screening of old patients by dermatologists in order to diagnose skin cancers early.

Modelling epidermis homoeostasis and psoriasis pathogenesis.

We present a computational model to study the spatio-temporal dynamics of epidermis homoeostasis under normal and pathological conditions. The model consists of a population kinetics model of the central transition pathway of keratinocyte proliferation, differentiation and loss and an agent-based model that propagates cell movements and generates the stratified epidermis. The model recapitulates observed homoeostatic cell density distribution, the epidermal turnover time and the multilayered tissue structure. We extend the model to study the onset, recurrence and phototherapy-induced remission of psoriasis. The model considers psoriasis as a parallel homoeostasis of normal and psoriatic keratinocytes originated from a shared stem cell (SC) niche environment and predicts two homoeostatic modes of psoriasis: a disease mode and a quiescent mode. Interconversion between the two modes can be controlled by interactions between psoriatic SCs and the immune system and by normal and psoriatic SCs competing for growth niches. The prediction of a quiescent state potentially explains the efficacy of multi-episode UVB irradiation therapy and recurrence of psoriasis plaques, which can further guide designs of therapeutics that specifically target the immune system and/or the keratinocytes.

Algae extract protection effect on oxidized protein level in human stratum corneum.

Modification of proteins by reactive oxygen species is implicated in different disorders. The proteasome is a multicatalytic proteinase in charge of intracellular protein turnover and of oxidized proteins degradation. Consequently, proteasome function is very important in controlling the level of altered proteins in eukaryotic cells. Evidence for a decline in proteasome activity during skin photo-aging has been provided in Bulteau et al. in 2002. The ability of a lipid algae extract (Phaeodactylum tricornutum) to stimulate 20S proteasome peptidase activities was described by Nizard et al. in 2001. Furthermore, keratinocytes treated with Phaeodactylum tricornutum extract and then UVA and UVB irradiated, exhibited a sustained level of proteasome activity comparable to the one of nonirradiated cells. The level of modified proteins can be quantified by measurement of protein carbonyl content (Oxyblot technique), which has been shown to increase with aging and other disorders. In this paper, it is described that, in the presence of this lipid algae extract, the level of oxidized proteins is reduced, as assessed by the Oxyblot technique. These results are obtained both with culture of human keratinocytes and stratum corneum skin cells (obtained by stripping) from human volunteers. Altogether, these results argue for the presence of compounds in this algae extract that have a stimulating and/or protective effect on proteasome activity, resulting in a decreased level of protein oxidation.

Quantitative assessment of properties of make-up products by video imaging: application to lipsticks.

BACKGROUND/AIMS: The different properties and visual effects of lipstick have been studied by image analysis directly on volunteers. METHODS: After controlling the volunteer's position mechanically using an ophthalmic table and visually using an acquirement mask, which is an indicator of luminance and guide marks, we carried out video colour images of the make-up area. From these images, we quantified the colour, gloss, covering power, long-lasting effect and streakiness, using computer science programs. RESULTS/CONCLUSION: Quantitative colorimetric assessment requires the transformation of the RGB components obtained by a video colour camera into CIELAB colorimetric space. The expression of each coordinate of the L*a*b* space according to R,G,B was carried out by a statistical method of polynomial approximations. A study, using 24 colour images extracted from a Pantone(R) palette, showed a very good correlation with a Minolta Colorimeter(R) CR 300. The colour assessment on volunteers required a segmentation method by maximizing the entropy. The aim was to separate the colour information sent back by the skin to the make-up area. It was very useful to precisely delimit the contour between the skin and the product in the case of almost identical colours and to evaluate the streakiness. From this colour segmentation, an algorithm was studied to search for the shades most represented in the overall colour of the make-up area. The capacity to replicate what the consumer perceives of the make-up product, to carry out studies without having any contact with the skin surface, and the constant improvement of software and video acquirement systems all make video imaging a very useful tool in the quantitative assessment of the properties and visual effects of a make-up product.

Transcriptional effect of an Aframomum angustifolium seed extract on human cutaneous cells using low-density DNA chips.

BACKGROUND: Studying photoexposed and photoprotected skin biopsies from young and aged women, it has been found that a specific zone, composed of the basal layers of the epidermis, the dermal epidermal junction, and the superficial dermis, is major target of aging and reactive oxygen species. We showed that this zone is characterized by significant variations at a transcriptional and/or protein levels. AIMS: Using low-density DNA chip technology, we evaluated the effect of a natural mixture of Aframomum angustifolium seed extract containing labdane diterpenoids on these aging markers. METHODS: Expression profiles of normal human fibroblasts (NHF) were studied using a customized cDNA macroarray system containing genes covering dermal structure, inflammatory responses, and oxidative stress defense mechanisms. For normal human keratinocyte (NHK) investigations, we chose OLISA technique, a sensitive and quantitative method developed by BioMérieux specifically designed to investigate cell death, proliferation, epidermal structure, differentiation, and oxidative stress defense response. RESULTS: We observed that this extract strongly modified gene expression profiles of treated NHK, but weakly for NHF. This extract regulated antioxidant defenses, dermal-epidermal junction components, and epidermal renewal-related genes. CONCLUSION: Using low-density DNA chip technology, we identified new potential actions of A. angustifolium seed extract on skin aging.

Evaluation of a sunscreen photoprotective effect by ascorbic acid assessment in human dermis using microdialysis and gas chromatography mass spectrometry.

Ultraviolet irradiation causes adverse effects like sunburn, photosensitivity reactions or immunologic suppression. The aim of this study was to evaluate the photo-protective outcome of a sunscreen cream (SPF8) by the determination of erythema indexes and the assessment of ascorbic acid and its metabolites in human dermis. These substances were used as markers of oxidative effect. Eight healthy female subjects were enrolled in this study. Two abdominal areas were exposed to solar simulated irradiation with three minimal erythema dose, one with SPF8 application and the other site without SPF8 application. Two other areas were used as control, one without SPF8 application and the other site after SPF8 application. Ascorbic acid and its metabolites (dehydroascorbic acid, threonic acid, oxalic acid and xylose) were collected from human dermis by microdialysis and assessed by gas chromatography mass spectrometry. Irradiated site without sunscreen application had significantly demonstrated lower dermis ascorbic acid concentrations and a higher erythema index than the three other sites (P < 0.05). Threonic acid, oxalic acid and xylose dermis concentrations were significantly higher in site III than in the control site I (P < 0.05). The protected-irradiated site did not show erythema formation and there was stability of ascorbic acid dermis concentrations with non-variation in its metabolites. The assessment of ascorbic acid and its metabolites in human dermis could be an efficient tool to demonstrate the oxidative process and consequently to control the efficiency of sunscreen creams against undesirable UV effects.