Targeting SDF-1 as an efficient strategy to resolve skin hyperpigmentation issues with Himanthalia elongata extract.

BACKGROUND: During aging, human skin is facing hyperpigmentation disorders: senile lentigo (chronobiologic aging) leads to loss of melanogenesis' control while solar lentigo (UV exposure) promotes an increase of oxidized proteins, melanogenesis, and lipofuscin. AIMS: Stromal-cell-derived-factor-1 (SDF-1) was identified as key regulator of hyperpigmentation and its expression is reduced in senescent fibroblasts, highlighting this protein as new target for skin hyperpigmentation. MATERIALS: We developed two skin explant models mimicking of senile and solar lentigo, based on H2 O2 systemic treatment and UV irradiation, respectively. We evaluated Himanthalia elongata extract (HEX) on these models after 5 days of treatment and analyzed SDF-1 expression and skin pigmentation. For solar lentigo, we also analyzed oxidized proteins and lipofuscin accumulation. Finally, we evaluated HEX in vivo on nearly 100 multi ethnicities' volunteers. RESULTS: SDF-1 expression decreased in senile lentigo model, associated with hyperpigmentation. HEX application restored SDF-1 expression, leading to skin pigmentation decrease. For solar lentigo, we showed an impact of UVs on SDF-1 expression linked to hyperpigmentation, while the application of HEX restored SDF-1 expression and reduced skin pigmentation. On same model, HEX reduced oxidized proteins quantity and lipofuscin which increased after UV exposure. Clinically, HEX reduced dark spot pigmentation on Caucasian volunteers' hands and on Asian and African volunteers' face after 28 days. DISCUSSION: We have developed ex vivo models mimetic of senile and solar lentigo and showed for a very first time that SDF-1 can be also a key regulator for UV-induced hyperpigmentation. CONCLUSION: Our ex vivo and clinical studies highlighted the power of HEX with strong reduction of dark spots regardless of volunteers' ethnicities.

The anti-wrinkles properties of sodium acetylated hyaluronate.

BACKGROUND: Intrinsic aging promotes wrinkles formation by an imbalance between matrix synthesis/degradation in favor of degradation. This is accelerated by the exposome leading to overproduction of protease and fewer remodeling. OBJECTIVE: Protecting the integrity of extracellular matrix appears as the most efficient anti-aging solution. We developed a grafted HA specifically designed to get anti-aging property due to a specific molecular weight and acetylation degree. METHODS: A transcriptomic analysis was performed on fibroblasts, followed by a measurement of MMP secretion and subsequent effect on collagen degradation. MMP expression in skin explants concerned by chronobiological and extrinsic aging was analyzed by immunostaining. A clinical study was conducted on volunteers presenting wrinkles on face to evaluate flash reduction of wrinkles after 6 h of application by profilometry and anti-aging efficacy after 2 months by VISIA® CR2.3. RESULTS: Transcriptomic analysis evidenced an inhibition of MMP gene expression with acetylated HA, confirmed by an inhibition of MMPs release by fibroblasts, and a protection of type I collagen against degradation. We confirmed the reduction of MMPs in mature skin and in skin explants exposed to UV and urban dust. We demonstrated during clinical studies the flash reduction effect of acetylated HA on crow's feet wrinkles and a filling of nasogenian areas 6 h after application, and a wrinkles number reduction on nasogenian area up to 2 months of application. CONCLUSION: We developed a new grafted HA owing protective properties against ECM degradation induced by chronobiological and extrinsic aging, leading to a significant and efficient anti-wrinkles effect.

Combining Raman imaging and MCR-ALS analysis for monitoring retinol permeation in human skin.

BACKGROUND: Monitoring the transcutaneous permeation of exogenous molecules using conventional techniques generally requires long pre-analytical preparation or labelling of samples. However, Raman spectroscopy is a label-free and non-destructive method which provides spatial distribution of tracked actives in skin. The aim of our study was to prove the interest of Raman imaging coupled with multivariate curve resolution alternating least square (MCR-ALS) analysis in monitoring retinol penetration into frozen and living human skin. MATERIALS AND METHODS: After topical treatment of skin samples by free or encapsulated retinol, thin cross sections were analysed by Raman imaging (up to 100 µm depth). Mann-Whitney test was used to identify retinol spectroscopic markers in skin. MCR-ALS was used to estimate retinol contribution in Raman spectral images. Heat maps were constructed to compare the distribution of free and encapsulated retinol in skin models. RESULTS: We identified the bands at 1158, 1196 and 1591 cm-1 as specific features for monitoring retinol in skin. Moreover, our MCR-ALS results showed an improvement of retinol penetration (up to 30 µm depth) with the encapsulated form as well as storage reservoir formation in stratum corneum, for each skin model. Finally, greater retinol penetration into living skin was observed. CONCLUSION: This study shows a proof of concept for the evaluation of retinol penetration in skin using Raman imaging coupled with MCR-ALS. This concept needs to be validated on more subjects to include inter-individual variability but also other factors affecting skin permeation (age, sex, pH, etc). Our study can be extended to other actives.

Mannose-6-phosphate complex and improvement in biomechanical properties of the skin.

BACKGROUND: The dermis is composed of a tangle of macromolecules that provides the skin its biomechanical properties. During chronological aging, fibroblasts lose their ability to synthesize collagen and an accumulation of matrix metalloproteinases leads to an increase in collagen degradation. As a result, there is a decline in the biomechanical properties of the skin. Skin aging is accelerated by external factors such as UV radiation and pollution, which induce accumulation of oxidants, and so of oxidized proteins in the skin. AIMS: Atomic force microscopy (AFM) has emerged as an alternative method for studying the biomechanical properties of skin cells and tissues. METHODS/RESULTS: Thus, we identified mannose-6-phosphate complex as a new powerful molecule capable of reversing the visible signs of aging by reorganizing the collagen network of the dermis and by improving the skin biomechanical properties. This effect was correlated with clinical studies that showed a marked antiaging effect through a reduction in the number of crow's feet and in the depth and size of neck wrinkles. CONCLUSION: Mannose-6-phosphate complex appeared to be able to protect proteins in the dermis scaffold against oxidation and degradation, allowing an improvement in the skin biomechanical properties.

Overall renewal of skin lipids with Vetiver extract for a complete anti-ageing strategy.

OBJECTIVE: Skin lipids are essential in every compartment of the skin where they play a key role in various biological functions. Interestingly, their role is central in the maintenance of hydration which is related to skin barrier function and in the skin structure through adipose tissue. It is well described today that skin lipids are affected by ageing giving skin sagging, wrinkles and dryness. Thereby, developing cosmetic actives able to reactivate skin lipids would be an efficient ant-ageing strategy. Due to the strong commitment of our scientists to innovate responsibly and create value, they designed a high value active ingredient named here as Vetiver extract, using a ground-breaking upcycling approach. We evidenced that this unique extract was able to reactivate globally the skin lipids production, bringing skin hydration and plumping effect for mature skin. METHOD: In order to demonstrate the global renewal of lipids, we evaluated the lipids synthesis on cutaneous cells that produce lipids such as keratinocytes, sebocytes and adipocytes then on Reconstructed Human Epidermis and skin explants. We evaluated the expression of proteins involved in ceramides transport and barrier cornification. We then evaluated hydration and sebaceous parameters on a panel of mature volunteers. RESULTS: We firstly demonstrated that Vetiver extract induced sebum production from human sebocytes cells lines but also improved its quality as observed by the production of specific antimicrobial lipids. Secondly, we demonstrated that Vetiver extract was able to restore skin barrier with the increase of skin lipids neosynthesis on Reconstructed Human Epidermis and skin explants. We also evidenced that Vetiver extract stimulated the lipids transport and epidermal cornification. Finally, Vetiver extract showed a significant effect on adipogenesis and maturation of adipocytes at in vitro and ex vivo models. We confirmed all these activities by showing that Vetiver extract improved sebum production and brought hydration through an increase of lipids content and their conformation. Vetiver extract induced an improvement of skin fatigue and a plumping effect by acting deeply on adipose tissue. CONCLUSION: In conclusion, we developed an active ingredient able to bring anti-ageing effect for mature skin by a global increase of skin lipids.

OBJECTIF: Les lipides de la peau sont essentiels dans chaque compartiment de la peau où ils jouent un rôle clé dans diverses fonctions biologiques. Il est intéressant de noter que leur rôle est central dans le maintien de l'hydratation, liée à la fonction de barrière cutanée, mais aussi dans la structure même de la peau, par le biais du tissu adipeux. Il est bien décrit aujourd'hui que les lipides de la peau sont affectés par le vieillissement, ce qui entraîne un relâchement de la peau, des rides et une sécheresse. Ainsi, le développement d'actifs cosmétiques capables de réactiver les lipides de la peau serait une stratégie efficace de lutte contre le vieillissement. En raison de l'engagement fort de nos scientifiques à innover de manière responsable et à créer de la valeur, ils ont conçus un ingrédient actif à forte valeur ajoutée, appelé ici extrait de Vétiver, en utilisant une approche révolutionnaire de « up-cycling ¼. Nous avons démontré que cet extrait unique était capable de réactiver globalement la production de lipides de la peau, apportant une hydratation de la peau et un effet repulpant pour les peaux matures. MÉTHODES: Afin de démontrer le renouvellement global des lipides, nous avons évalué la synthèse des lipides sur les cellules cutanées qui produisent des lipides tels que les kératinocytes, les sébocytes et les adipocytes, puis sur un modèle d'Epiderme Humain Reconstruit et les explants de peau. Nous avons évalué l'expression des protéines impliquées dans le transport des céramides et la kératinisation de la barrière cutanée. Nous avons ensuite évalué l'hydratation et les paramètres sébacés sur un panel de volontaires matures. RÉSULTATS: Nous avons tout d'abord démontré que l'extrait de Vétiver induit la production de sébum à partir de lignées cellulaires de sébocytes humains mais améliore également sa qualité comme l'indique la production de lipides antimicrobiens spécifiques. Ensuite, nous avons démontré que l'extrait de Vétiver était capable de restaurer la barrière cutanée grâce à l'augmentation de la néosynthèse lipidique sur un modèle d'Epiderme Humain Reconstruit et sur des explants de peau. Nous avons également démontré que l'extrait de Vétiver stimulait le transport des lipides et la kératinisation de l'épiderme. Enfin, l'extrait de Vétiver a montré un effet significatif sur l'adipogenèse et la maturation des adipocytes dans des modèles in vitro et ex vivo. Nous avons confirmé à l'échelle clinique toutes ces activités en montrant que l'extrait de Vétiver améliorait la production de sébum et apportait une hydratation grâce à une augmentation de la teneur en lipides ainsi qu'une modification de leur conformation. L'extrait de Vétiver a induit une amélioration de la fatigue cutanée et un effet repulpant en agissant en profondeur sur le tissu adipeux. CONCLUSION: En conclusion, nous avons développé un ingrédient actif capable d'apporter un effet anti-âge aux peaux matures par une augmentation globale des lipides de la peau.

Well-aging: A new strategy for skin homeostasis under multi-stressed conditions.

BACKGROUND: Several studies evidenced significant increase of cortisol is the consequence of UV or emotional stress and leads to various deleterious effects in the skin. AIM: The well-aging, a new concept of lifestyle, procures an alternative to the anti-aging strategy. We demonstrated that Tephrosia purpurea extract is able to stimulate well-being hormones while reducing cortisol release. Furthermore, we hypothesized that the extract could positively influence the global skin homeostasis. METHOD: We evaluated the impact of the extract on cortisol, ß-endorphin, and dopamine, released by normal human epidermal keratinocytes (NHEKs). A gene expression study was realized on NHEKs and NHDFs. The protein over-expression of HMOX1 and NQO1 was evidenced at cellular and tissue level. Finally, we conducted a clinical study on 21 women living in a polluted environment in order to observe the impact of the active on global skin improvement. RESULTS: The extract is able to reduce significantly the cortisol release while inducing the production of ß-endorphin and dopamine. The gene expression study revealed that Tephrosia purpurea extract up-regulated the genes involved in antioxidant response and skin renewal. Moreover, the induction of HMOX and NQO1 expression was confirmed on NHDFs, NHEKs and in RHE. We clinically demonstrated that the extract improved significantly the skin by reducing dark circles, represented by an improvement of L*, a*, and ITA parameters. CONCLUSION: Tephrosia purpurea extract has beneficial effects on skin homeostasis through control of the well-being state and antioxidant defenses leading to an improvement of dark circles, a clinical features particularly impacted by emotional and environmental stress.

Regeneration of human dermis by a multi-headed peptide.

Skin aging is characterized by deterioration of the dermal collagen fiber network due to both decreased collagen expression and increased collagenolytic activity. We designed and evaluated in vitro and ex vivo the efficacy of a trifunctional peptide (TFP) to restore collagen and elastin fibers. TFP was constituted of an elastokine motif (VGVAPG)3, able to increase matrix constituent expression through the stimulation of the elastin-binding protein receptor, a GIL tripeptide occupying matrix metalloproteinase-1 subsites, and a RVRL linker domain acting as a competitive substrate for urokinase. The effects of TFP on type I, type III collagens, and elastin expression in dermal fibroblasts were determined by quantitative real-time reverse-transcriptase-PCR and western blotting. TFP's inhibitory capacity against MMP-1, plasmin, and urokinase was assessed using synthetic substrates, immunohistochemistry, and skin tissue sections as natural substrates. A skin explant model was used to recapitulate aging-induced dermal changes along culture extent. Collagen and elastin fiber structure was analyzed by two-photon fluorescence, second harmonic generation, and confocal microscopies. Compared with the different sections constituting the full peptide, we found that TFP activated the production of matrix constituents while inhibiting MMP-1 in vitro and ex vivo. It also induced a proper fiber network organization, reflecting the potency of TFP in skin remodeling and regeneration.