5-α reductase inhibition by Epilobioum fleischeri extract modulates facial microbiota structure.

BACKGROUND: Facial skin is a particularly complex environment made of different skin types such as sebaceous (forehead) and dry (cheeks). The skin microbiota composition on different facial sites has not yet been addressed. METHODS: We conducted a 4-week-long, single-centre, randomized and placebo-controlled clinical study involving 23 Caucasian females. We assessed both bacterial composition on five different facial areas and the microbiome modulatory effects resulting from the topical application of a plant extract (Epilobium fleischeri). Skin microbiome samples were collected before and after 4 weeks of product application. Microbiota profiling was performed via 16S rRNA gene sequencing, and relative abundance data were used to calculate differentials via a multinomial regression model. RESULTS: Via 'reference frames', we observed shifts in microbial composition after 4 weeks of twice-daily product application and identify certain microbiota species, which were positively associated with the application of the product containing the Epilobium fleischeri extract. Staphylococcus hominis, Staphylococcus epidermidis, and Micrococcus yunnanensis appeared to be significantly enriched in the final microbiota composition of the active treatment group. CONCLUSION: Facial skin was found to be colonized by an heterogenous microbiota, and the Epilobium fleischeri extract had a modulatory effect on commensal bacteria on the different facial sites.

CONTEXTE: la peau du visage est un environnement particulièrement complexe où l'on trouve des peaux de plusieurs types, par exemple grasse (sur le front) et sèche (sur les joues). La composition du microbiote cutané sur différentes zones du visage n'a pas encore été abordée. MÉTHODES: nous avons mené une étude clinique de 4 semaines monocentrique, randomisée et contrôlée par placebo sur 23 femmes de type caucasien. Nous avons évalué à la fois la composition bactérienne sur cinq zones différentes du visage et les effets modulateurs du microbiome résultant de l'application topique d'un extrait de plante (Epilobium fleischeri). Des échantillons de microbiome cutané ont été prélevés avant et après 4 semaines d'application du produit. Un profilage du microbiote a été mené par séquençage du gène de l'ARNr 16S, des données d'abondance relative ont été utilisées pour calculer les différentiels via un modèle de régression multinomiale. RÉSULTATS: nos cadres de référence nous ont permis d'observer des changements de composition microbienne après 4 semaines d'application deux fois par jour du produit et nous avons identifié certaines espèces de microbiote qui ont été positivement associées à l'application du produit contenant l'extrait d'Epilobium fleischeri. Les taux de Staphylococcus hominis, Staphylococcus epidermidis et Micrococcus yunnanensis semblaient significativement plus élevés dans la composition finale du microbiote du groupe de traitement actif. CONCLUSION: la peau du visage s'est avérée colonisée par un microbiote hétérogène, et l'extrait d'Epilobium fleischeri a eu un effet modulateur sur les bactéries commensales des différentes zones du visage.

Effect of regioisomers of hydroxystearic acids as peroxisomal proliferator-activated receptor agonists to boost the anti-ageing potential of retinoids.

INTRODUCTION: We report on the in vitro and ex vivo effects of chiral (R)-10-hydroxystearic acid (10-HSA) compared with other mono-hydroxystearic acid regioisomers and stearic acid (SA) together with its benefit when combined with retinol. METHODS: Following treatment with hydroxystearic acids peroxisomal proliferator-activated receptor alpha (PPARα) activity was determined in a luciferase reporter gene assay, collagen type I was assessed in primary human dermal fibroblasts by immunohistochemistry, modification of the intracellular fibroblast collagen proteome was studied by mass-spectrometry-based proteomics and collagen type III was assessed by immunohistochemistry on human ex vivo skin. RESULTS: 10-HSA was the most effective PPARα agonist (15.7× induction; p < 0.001), followed by 9-HSA (10.1× induction) and then 12-HSA (4.9× induction) with 17-HSA (1.7× induction) being similar to the effects of stearic acid (1.8× induction). Collagen type I levels were increased in primary human fibroblasts by 2.12× and 1.56× for 10-HSA and 9-HSA, respectively, in vitro with the10-HSA being significant (p < 0.05), whereas 12-HSA and SA had no statistical effect over the untreated control. 10-HSA and 12-HSA modified the intracellular fibroblast collagen proteome slightly with significant increases in collagen alpha-1 (VI) and alpha-3 (VI) proteins but only 10-HSA increased levels of collagen alpha-2 (V), alpha-1 (III), alpha-1 (I) and alpha-2 (I) (all p < 0.05) with the increases being significantly different between 10-HSA and 12-HSA for collagen alpha-1 (I), collagen-3 (VI) and collagen alpha-2 (I) (p < 0.01). Collagen type III in ex vivo skin was increased +47% (p < 0.05) by 0.05% (1.7 mM) retinol, +70% (p < 0.01) by 0.01% (0.33 mM) 10-HSA and the combination increased levels by +240% (p < 0.01 for either ingredient). CONCLUSION: Chiral (R)-10-HSA has been shown to be superior to 9, 12 and 17-HSA as a PPARα agonist. Moreover, 10-HSA stimulated collagen synthesis in monolayer fibroblast culture as assessed by proteomics and immunohistochemically. Furthermore, we also show the synergistic effects of 10-HSA with retinol on collagen III synthesis in skin explants. These results further highlight the efficacy of 10-HSA as a cosmetically acceptable PPARα agonist and anti-ageing ingredient.

INTRODUCTION: Nous rapportons les effets in vitro et ex vivo de l'acide chiral (R)-10-hydroxystéarique (10-HSA) par rapport à d'autres régioisomères d'acide mono-hydroxystéarique et à l'acide stéarique (SA) ainsi que ses avantages lorsqu'il est associé au rétinol. MÉTHODES: Après un traitement avec des acides hydroxystéariques, l'activité du récepteur alpha activé par les proliférateurs peroxysomaux (PPARα) a été déterminée dans un test du gène rapporteur de la luciférase, le collagène de type I a été évalué dans les fibroblastes dermiques humains primaires par immunohistochimie, la modification du protéome du collagène des fibroblastes intracellulaires a été étudiée par spectrométrie de masse. La protéomique et le collagène de type III ont été évalués par immunohistochimie sur la peau humaine ex vivo. RÉSULTATS: la 10-HSA était l'agoniste PPARα le plus efficace (induction 15,7X ; p<0,001), suivi de la 9-HSA (induction 10,1X) puis de la 12-HSA (induction 4,9X) avec la 17-HSA (induction 1,7X) étant similaire aux effets de l'acide stéarique (induction 1,8X). Les niveaux de collagène de type I ont été augmentés dans les fibroblastes humains primaires de 2,12X et 1,56X pour la 10-HSA et la 9-HSA respectivement in vitro, la 10-HSA étant significative (p<0,05) : alors que la 12-HSA et la SA n'ont eu aucun effet statistique sur le témoin non traité. La 10-HSA et la 12-HSA ont légèrement modifié le protéome du collagène des fibroblastes intracellulaires avec des augmentations significatives des protéines de collagène alpha-1 (VI) et alpha-3 (VI), mais seule la 10-HSA a augmenté les niveaux de collagène alpha-2 (V), alpha -1 (III), alpha-1 (I) et alpha-2 (I) (tous p<0,05) avec des augmentations significativement différentes entre 10-HSA et 12-HSA pour le collagène alpha-1 (I), le collagène- 3 (VI) et Collagène alpha-2 (I) (p<0,01). Le collagène de type III dans la peau ex vivo a augmenté de +47 % (p<0,05) de 0,05 % (1,7 mM) de rétinol, de +70 % (p<0,01) de 0,01 % (0,33 mM) de 10-HSA et la combinaison a augmenté les niveaux de +240 % (p<0,01 pour chaque ingrédient). CONCLUSION: La chiral (R)-10-HSA s'est avérée supérieure à 9, 12 et 17-HSA en tant qu'agoniste de PPARα. De plus, la 10-HSA a stimulé la synthèse de collagène dans la culture de fibroblastes monocouche telle qu'évaluée par protéomique et immunohistochimique. De plus, nous montrons également les effets synergiques de la 10-HSA avec le rétinol sur la synthèse du collagène III dans les explants de peau. Ces résultats soulignent en outre l'efficacité de la 10-HSA en tant qu'agoniste de PPARα et ingrédient anti-âge cosmétiquement acceptable.

Discovery of a Highly Selective MC1R Agonists Pentapeptide to Be Used as a Skin Pigmentation Enhancer and with Potential Anti-Aging Properties.

One of the first lines of cutaneous defense against photoaging is a) the synthesis of melanin and b) the initiation of an oxidative stress response to protect skin against the harmful effects of solar radiation. Safe and selective means to stimulate epidermal pigmentation associated with oxidative stress defense are; however, scarce. Activation of the melanocortin-1 receptor (MC1R) on epidermal melanocytes represents a key step in cutaneous pigmentation initiation and, additionally, it regulates cellular defense mechanisms like oxidative stress and DNA-repair. Thus, making the activation of MC1R an attractive strategy for modulating skin pigmentation and oxidative stress. In this context, we designed and synthesized pentapeptides that act as MC1R agonists. These peptides bound, with high potency, to MC1R and activated cAMP synthesis in CHO cells expressing human MC1R. Using one lead pentapeptide, we could show that this activation of MC1R was specific as testing the activation of other G-protein coupled receptors, including the MC-receptor family, was negative. In vitro efficacy on mouse melanoma cells showed similar potency as for the synthetic MC1R agonist alpha-melanocyte stimulating hormone (NDP-alpha-MSH). Moreover, we could reproduce this activity in human skin tissue culture. The lead pentapeptide was able to induce ex-vivo protein expression of key melanogenesis markers melanocyte inducing transcription factor (MITF), tyrosinase (TYR), and tyrosinase-related protein 1 (TYRP-1). Concerning oxidative stress response, we found that the pentapeptide enhanced the activation of Nrf2 after UVA-irradiation. Our results make this pentapeptide an ideal candidate as a skin pigmentation enhancer that mimics alpha-MSH and may also have anti-photoaging effects on the skin.

Effects of the selective TrkA agonist gambogic amide on pigmentation and growth of human hair follicles in vitro.

The human hair follicle is a neuroendocrine mini-organ that can be used to study aging processes in vitro. Neurotrophins maintain homeostasis in hair biology via the Trk-family of receptors. TrkA, the high affinity receptor for nerve growth factor (NGF), is expressed in hair follicle melanocytes and keratinocytes, where it regulates proliferation, differentiation and apoptosis and may thereby play a role in hair pigmentation and growth. We investigated TrkA expression during the human hair cycle and the effects of a selective high affinity TrkA agonist, Gambogic Amide, on hair pigmentation and hair growth in human hair follicles in vitro. In human scalp skin, TrkA expression was strongest in proliferating melanocytes re-establishing the pigmentary unit in the hair bulb during the early hair growth phase, anagen. During high anagen and in the de-composing pigmentary-unit of the regression phase, catagen, bulb-melanocytes lost TrkA expression and only undifferentiated outer root sheath melanocytes maintained it. In cultured human anagen hair follicles, Gambogic Amide was able to prevent gradual pigment loss, while it stimulated hair shaft elongation. This was achieved by increased melanocyte activation, migration and dendricity, highlighted by distinct c-KIT-expression in melanocyte sub-populations. Our results suggest that Gambogic Amide can maintain hair follicle pigmentation by acting on undifferentiated melanocytes residing in the outer root sheath and making them migrate to establish the pigmentary-unit. This suggests that the selective TrkA agonist Gambogic Amide acts as an anti-hair greying and hair growth promoting molecule in vitro.

Appearance of aging signs in differently pigmented facial skin by a novel imaging system.

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, IWANewtone , 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) and Black 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 IWANewtone 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.

Profiling mRNA of the graying human hair follicle constitutes a promising state-of-the-art tool to assess its aging: an exemplary report.

Determining hitherto uninvestigated and safe targets to halt the aging process is important in our aging society. Graying is a hallmark of the aging process and may be used to identify aging tissue for comparative analysis. Here we analyzed differential gene expressions between pigmented, gray, and white human scalp skin hair follicles (HFs) from identical donors. Forming intersections between five donors identified 194/192 downregulated and 186/177 upregulated genes in gray/white HFs. These included melanogenesis (tyrosinase; tyrosinase-related protein 1)- and melanosome structure (Melan-A; Pmel17)-associated genes and regulation of melanocyte relevant tyrosine kinases. Alongside these expected changes, regulated genes included nonmelanocyte-related genes associated with aging as well as nonaging-related genes associated with melanocytes. Intriguingly, among them, genes associated with energy metabolism (i.e., glutaminase) and axon guidance (plexin C1) were altered. These results were reflected by pathway analysis and exemplarily confirmed by PCR and immunohistochemical studies. Supplementing cultured HFs with glutamine or plexin C1 revealed biological relevance and pharmacointerventional potential of these microarray results in altering the HF aging process. Together, we present intriguing data obtained from intra-individual sample comparison that suggest the graying HF to be a valid aging model and a promising target for testing therapeutic interventions.

Graying of the human hair follicle.

Quality of life in our society depends crucially on healthy aging, a hallmark of which is the graying hair follicle. During anagen melanocyte precursors migrate to the hair bulb to form the pigmentary unit where they mature and synthesize melanin. Melanin is transferred to the hair shaft forming keratinocytes giving the hair its colour. Graying is the process in which distinct mechanisms lead to deterioration of the hair follicle melanocyte population. We briefly review the hair graying process and state that the aging hair follicle is a valid model for tissue specific aging and a promising target to test therapeutic intervention.