Skin aging has long been considered a purely cosmetic problem. However, as life expectancy increases, skin aging is taking on a functional dimension that goes beyond cosmetics and appearance. Preventive or therapeutic strategies are needed to target cellular senescence, a key process underlying the alterations in skin function and appearance that occur with aging, as well as to address the age-related skin changes associated with 'dermatoporosis' and chronic skin insufficiency/fragility syndrome. Thus, given the need for effective anti-aging products that improve both the appearance and function of the skin, it is essential to distinguish active ingredients that have been proven to be effective, among the large number of available over-the-counter cosmeceuticals. This brief review focuses on a core group of topical actives, describing their clinical effects on senescence and aging, and their molecular mechanisms of action. These actives include hyaluronic acid, which has hydrating and viscoelastic properties and has been shown to reduce skin atrophy; retinaldehyde, which activates retinoid receptors and increases cutaneous elasticity; vitamins C and E, which provide stable oxidative protection; and niacinamide, which reduces inflammation and mitigates the effects of senescence.

Intrinsic and extrinsic factors including UV or life style lead to an increase of senescent cells (SC) in skin that contribute to wrinkles, thinning and decreased elasticity. SC developed a specific secretome, called SASP (MMPs, CXCL, interleukin, S100A7/A8...) that drives skin aging through paracrine effects on neighboring cells and endocrine effects on cells at a distance. The reduction of SASP by using senotherapeutics is a promising strategy to reduce skin aging. Our aim was to demonstrate the senomorphic and anti-aging properties of a unique cosmetic formulation composed of 6% Niacinamide and 0.2% Hyaluronic acid. We included 30 females subjects between 42 and 55 years old. Formulation was used once a day, and after two months, biopsies were performed on forearm. Total RNA was extracted and Next Generation Sequencing and bioinformatics analysis were used to investigate formulation effect on mRNA and miRNA expression. Transcriptomic data showed a total of 101 differentially expressed mRNA. We observed a senomorphic effect (CXCL9, S100A7A, S100A8, S100A9 decrease), an increased of ECM densification (PTH2R increase and MMP12 decrease) and a decrease of inflammaging (CCL18, SERPINB4 and IGFL1 decrease). Furthermore, many miRNAs were identified, including miR-206 inhibition and miR-124-3p increase.These miR have an important role in aging. Indeed, downregulation of miR-206 alleviate H202-induced senescence and miR-124-3p overexpression protect against oxidative stress and inflammation. These transcriptional effects were associated with improved clinical sign of aging: wrinkles and fine lines (-15%) and plumping (+24%). Altogether, these results showed for the first time, from a pharmaco-clinical level that an anti-aging formula has senomorphic properties.

Intrinsic and extrinsic factors, including lifestyle and sun exposure, can contribute to cell senescence, which impairs skin homeostasis, that may in turn lead to skin aging. Senescent cells have a specific secretome, called the senescence-associated secretory phenotype (SASP) that includes MMPs, CXCLs and S100A8/9. Reducing the SASP with senotherapeutics is a promising strategy to reduce skin aging. Here we evaluated the effect of a formula containing niacinamide and hyaluronic acid, which are known to limit senescence and skin aging. We conducted three different studies. (1) Ex vivo explants treated with the formula had more collagen and glycosaminoglycan. (2) In a clinical trial with forty-four women, two months of treatment improved fine lines, wrinkles, luminosity, smoothness, homogeneity, and plumpness. (3) In a third study on thirty women, we treated one arm for two months and took skin biopsies to study gene expression. 101 mRNAs and 13 miRNAs were differentially expressed. We observed a likely senomorphic effect, as there was a decrease in many SASP genes including MMP12 and CXCL9 and a significant downregulation of autocrine signaling genes: S100A8 and S100A9. These pharmaco-clinical results are the first to demonstrate the senomorphic properties of an effective anti-aging formula in skin.

ObjectiveSkin ageing is linked to the accumulation of senescent cells and a "senescence-associated secretory phenotype" (SASP). SASP factors include chemokines, cytokines, and small extracellular vesicles (EVs) containing miRNAs. We characterized SASP profile markers in normal human dermal fibroblasts (HDFs) and evaluated the effect of Haritaki fruit extract on these senescence markers. MethodsSenescence was induced in HDFs by ionizing radiation (X ray), followed by 14 days of culture. Parallel incubations included fibroblasts treated for 12 days with 10 or 100 mu g/mL Haritaki (a standardized extract of Terminalia chebula fruit). Senescence was assessed on Day 14 according to cell morphology, beta-galactosidase activity, RT-qPCR measurement of SASP genes, as well as semi-quantitative (RT-qPCR) expression of miRNAs contained in EVs isolated from the medium. The size and distribution of EVs were measured by Nanoparticle Tracking Analysis. ResultsHuman dermal fibroblasts exhibited a senescent phenotype 14 days after ionizing-radiation, demonstrated by a flattened and irregular shape, increased beta-galactosidase activity and over-expression of SASP genes. CSF3, CXCL1, IL1 beta, IL6 and IL8 genes were increased by 1492%, 1041%, 343%, 478%, 2960% and 293%, respectively. The cell cycle inhibitor, CDKN1A, was increased by 357%, while COL1A1, was decreased by 56% and MMP1 was increased by 293%. NTA analysis of the EVs size distribution indicated a mix of exosomes (45-100 nm) and microvesicles (100-405 nm). miRNA expression in EVs was increased in senescent fibroblasts. miR 29a-3p, miR 30a-3p, miR 34a-5p, miR 24a-3p and miR 186-5p were increased in senescent HDF by 4.17-, 2.43-, 1.17-, 2.01, 12.5-fold, respectively. Incubation of senescent fibroblasts with Haritaki extract strongly decreased SASP mRNA levels and miRNA expression in EVs. ConclusionHaritaki strongly reduced SASP expression and EV-shuttled miRNAs in senescent fibroblasts. These results indicate that Haritaki has strong senomorphic properties and may be a promising ingredient for the development of new anti-ageing dermo-cosmetic products by inhibiting deleterious effects of senescent cells.

Skin aging is the consequence of two biological process: intrinsic genetically programmed factors and extrinsic environmental factors. At the cellular level, accumulation of senescent cells (SC) is also involved in skin aging. SC stop to proliferate but remain metabolically active. The secretome of SC (Senescence Associated Secretory Phenotype: SASP), is a cocktail of mediators like CSF3, CXCL1, IL8, IL1b, IL6, MMP-1 and -3, involved in skin aging. Extracellular vesicles (EV) have also been reported to act as cytokines during intercellular communication. They transport proteins, mRNAs and miRNAs, over short or long distances. miRNAs are a class of short, single-stranded, noncoding RNA molecules. As epigenetic modulators, miRNAs affect the protein levels of the target mRNAs without modifying the gene sequences. Several miRs are known to be involved in senescence and skin aging. The aim of our study was to evaluate, the effect of Haritaki fruit extract (HF extract) on SASP and senescence associated miRs contained in EV. Our results showed that, 14 days after ionizing radiation (7.5 Gy), human dermal fibroblasts presented a senescent phenotype: flattened and irregular shape, senescence associated ß-galactosidase activity, SASP expression (RT-PCR) and miR 24a-3p, miR 186-5p, miR 30a-3p and miR 29a-3p overexpression in EV (RT-PCR). Our results also showed that incubation of senescent fibroblasts with HF extract strongly decreased SASP mRNA level and miR 34a-5p, miR 24a-3p, miR 186-5p, miR 30a-3p and miR 29a-3p over-expression in EV. Taken together these results demonstrated that Haritaki fruit extract is a strong senomorphic agent with epigenetic effect, suggesting that it may be useful for the development of new anti-aging dermo-cosmetic products.

Skin aging is the consequence of two biological process: intrinsic genetically programmed factors and extrinsic environmental factors (sun exposure or lifestyle). At the cellular level, accumulation of senescent cells (SC) is also involved in skin aging. SC stop to proliferate but remain metabolically active. The secretome of SC (Senescence Associated Secretory Phenotype: SASP), is a cocktail of mediators (CSF3, CXCL1, IL8, IL1b, IL6, MMP-1 and -3) involved in skin aging. Extracellular vesicles (EV) have also been reported to act in a similar manner as cytokines during intercellular communication. They transport proteins, mRNAs and miRNAs, over short or long distances. miRNAs are a class of short, single-stranded, noncoding RNA molecules. By binding the specific 3'-UTRs sequence of the target mRNAs, they regulate the expression of multiple genes at the post-transcriptional level through degradation. For instance, miR 30a has been described as a key regulator of aging in human epidermis by regulating barrier function and keratinocytes apoptosis in human epidermis. The aim of our study was to evaluate, by RT-PCR, the effect of Haritaki fruit extract (HF extract) on SASP and senescence associated miR 30a-3p contained in EV. Our results showed that, 14 days after ionizing radiation (7.5 Gy), human dermal fibroblasts presented a senescent phenotype: flattened and irregular shape, senescence associated b-galactosidase activity, SASP over-expression (RT-PCR) and mir 30a-3p overexpression in EV (RT-PCR). Our results also showed that incubation of senescent fibroblasts with HF extract strongly decreased SASP mRNA level and miR 30a-3p expression in EV. Taken together these results demonstrated that Haritaki fruit extract is a strong senomorphic agent, suggesting that it may be useful for the development of new anti- aging dermo-cosmetic products.

The aim of this work is to explore the communication between fibroblasts (dermis) and keratinocytes (epidermis) in the process of skin aging. We thought that Extracellular vesicles (EVs) secreted by aged or senescent fibroblasts might promote and sustain epidermis aging. In order to get insight into a potential function of EVs in skin aging, we first investigated the impact of fibroblasts secretome on the clonogenic potential of keratinocytes. We found that EVs containing secretomes of young fibroblasts are able to improve clonogenic potential of keratinocytes from old donors in terms of number of Holoclones, Meroclones and Paraclones. To further investigate the role of fibroblast EV in this process, we purified and analyzed the content of EVs from human proliferative and senescent dermal fibroblasts from 6 young and 6 old donors and catalogued the therein contained miRNAs. We interestingly found 54 specific miRNAs secreted by dermal fibroblasts from aged donors. Among the top 10 most abundant ones, 6 were involved in physiological aging or photo-aging. Some of them were also found in the EVs of senescent cells, suggesting a potential interplay between aged and senescent cells in promoting the skin aging process through EV communication between dermal fibroblasts and keratinocyte stem cells. In addition, we identified 3 novel miRNAs specifically expressed in EVs of senescent cells as potential new target to prevent skin aging. To better understand the potential rejuvenation effect of EVs on aged skin, we investigated the impact of young secretome on old keratinocytes miRNA content. We found that young fibroblast EVs were able to specifically induce old keratinocyte expression of 126 miRNA. Among them, 70 miRNAs usually expressed in young keratinocytes were re-expressed in treated old keratinocytes. P. Bensadoun and M. Gabanou participated equally to this work.

The purpose of this clinical study was to identify suitable biomarkers for a better understanding of the molecular and organizational changes in human dermis during intrinsic and extrinsic ageing.

Introduction: Natural aging of skin tissues, the addition of the cumulative action of the time and radiation exposure result in skin atrophy, wrinkles and degeneration of the extracellular matrix (ECM). The aim of the study was to investigate the beneficial effect of a combination containing retinaldehyde (RAL), delta-tocopherol glucoside (delta-TC) and glycylglycine oleamide (GGO) and of a dermocosmetic containing the combination.Materials and methods: The protective effect of the combination was assessed through in vitro gene expression of ultraviolet (UV)-irradiated fibroblasts. A skin aging assay using UV light on ex vivo skin samples and a clinical study conducted in 36 women aged from 35 to 55 years with a minimum of level 4 to a maximum of level 6 on the crow's feet photoscale assessed the antiaging effect of the dermocosmetic.Results: When added to UV-irradiated fibroblasts, the combination substantially improved the ECM in activating the elastin fiber production (fibrillin 2, fibulin 1 and 5 and lysyl - oxidase-like 2) as well as that of proteins involved in the cellular ECM interactions (integrin beta 1, paxillin and actin alpha 2). An ex vivo photodamaged human skin model showed that the dermocosmetic formulation containing the combination of the active ingredients protected the elastic network against UV-induced alterations including both elastin and fibrillin-rich fibers in the dermis. A daily application of the dermocosmetic for 2 months on naturally aged skin resulted in a statistically significant improvement (p< 0.05) of visible signs of aging comprising crow's feet, wrinkles and periocular fine lines. Finally, the formulation was well tolerated.Conclusion: The dermocosmetic containing RAL, delta-TC and GGO provides a substantial benefit in the daily care of naturally aged skin in women aged 35-55 years.

Skin aging results in tissue atrophy, wrinkles and extracellular matrix (ECM) degradation. This study aimed to investigate the antiaging effect of a combination of three active ingredients: retinaldehyde (RAL), delta-tocopherol glucoside (δTG) and glycylglycine oleamide (GGO). The protective effect of the combination was assessed by gene expression in ultraviolet (UV)-irradiated fibroblasts. An ex vivo skin aging assay using UVA and a clinical study conducted in 36 women (35-55 years, level 4 to 6 on the crow's feet photo scale) assessed the anti-aging effect of a RAL/δTG/GGO formulation. In UV-treated fibroblasts, the combination improved the ECM in activating the elastin fiber production (fibrillin 2, fibulin 1 and 5, lysyl oxidase-like 2) as well as that of proteins involved in the cell/ECM interactions (integrin β1, paxillin, actin α2). The photodamaged human skin model showed that a RAL/δTG/GGO formulation protected the elastic network against UV-induced alterations including both elastin and fibrillin-rich fibers in the dermis. A daily application of the formulation for 2 months in women resulted in a significant improvement (p < 0.05) of visible signs of aging comprising crow's feet, wrinkles and periocular fine lines. Thus, the RAL/δTG/GGO combination had antiaging properties and provided a substantial benefit in the daily care of naturally aged skin in women.

Background: Glycation is an aging reaction of naturally occurring sugars with dermal proteins. Type I collagen and elastin are most affected by glycation during intrinsic chronological aging.Aim: To study the in vitro and ex vivo assays in human skin cells and explants and the antiaging effects of glycylglycine oleamide (GGO).Materials and methods: The antiglycation effect of GGO was assessed in a noncellular in vitro study on collagen and, ex vivo, by immunohistochemical staining on human skin explants (elastin network glycation). The ability of GGO to contract fibroblasts was assessed in a functional assay, and its anti-elastase (MMP-12) activity was compared to that of oleic acid alone, glycylglycine (GG) alone, and oleic acid associated with GG.Results: In vitro, GGO reduced the glycation of type I collagen. Ex vivo, GGO restored the expression of fibrillin-1 inhibited by glycation. Furthermore, GGO induced a tissue retraction of almost 30%. Moreover, the MMP-12 activity was inhibited by up to 60%.Conclusion: Under the present in vitro and ex vivo conditions, GGO prevents glycation of the major structural proteins of the dermis, helping to reduce the risk of rigidification. By maintaining the elastic function of the skin, GGO may be a promising sparring partner for other topical antiaging agents.

Similar to the entire organism, skin is subject to an unpreventable intrinsic ageing process due to telomere shortening (replicative senescence or chronological aging). The skin is also increasingly exposed to ambient ultraviolet (UV) irradiation leading to photoaging (extrinsic aging) characterized by wrinkles, loss of skin tone and solar lentigines. Solar lentigines are macular hyperpigmented skin lesions. The aim of this study was to evaluate the properties of a combination of molecules on skin aging: Snow algae extract, tocopheryl acetate (AcVitE), ascorbyl glucoside (AA2G) and niacinamide (Vitamin B3). These molecules were studied in vitro on two different models of fibroblasts senescence: Hayflick model mimicking replicative senescence, stress-induced premature senescence mimicking extrinsic aging. A formulation containing these 4 compounds was also evaluated on a photoaging ex vivo human skin model (chronic UVA radiation of skin explant). We have showed on senescent fibroblasts (Hayflick model) that Snow algae extract increased Klotho (gene involved in longevity) mRNA level up to + 365%. Furthermore, using Comet-assay, we have also showed that tocopheryl acetate protected DNA of human keratinocytes against solar exposition (UVA and UVB). We have also showed the ascorbyl glucoside enhanced type I collagen synthesis in human fibroblastes (+66%) and decreased melanin synthesis (-56%) in human melanocytes. On the other hand, confocal microscopy revealed that chronic UVA exposure (3 x 12 J/cm2 at 365 nm) strongly induced MMP1 staining in irradiated skin explants. Topical application of the anti-aging formulation containing Snow algae extract, AA2G, AcVitE and VitB3 at 5 mg/cm2 efficiently decreased MMP1 staining and thus protected skin from UVA damage. In conclusion, using different in vitro models of senescence (intrinsic and extrinsic senescence), we demonstrated the anti-aging properties of Snow algae extract, AA2G, AcVitE and VitB3. This results have been confirmed with an ex vivo human skin model of photoaging.

Similar to the entire organism, skin is subject to an unpreventable intrinsic ageing process due to telomere shortening (replicative senescence). The skin is also increasingly exposed to ambient ultraviolet irradiation leading to photoaging (extrinsic aging) characterized by wrinkles, loss of skin tone and solar lentigines. Solar lentigines are macular hyperpigmented skin lesions. The aim of this study was to evaluate the properties of a combination of molecules on skin aging: Snow algae extract, tocopheryl acetate (AcVitE), ascorbyl glucoside (AA2G) and niacinamide (Vitamin B3). These molecules were studied in vitro on two different models of fibroblasts senescence: Hayflick model mimicking replicative senescence, stress-induced premature senescence mimicking extrinsic aging. A formulation containing these 4 compounds was also evaluated on a photoaging ex vivo human skin model (chronic UVA radiation of skin explant). We have showed on senescent fibroblasts (Hayflick model) that Snow algae extract increased Klotho (gene involved in longevity) mRNA level up to + 365%. Furthermore, using Comet-assay, we have also showed that tocopheryl acetate protected DNA of human keratinocytes against solar exposition (UVA and UVB). We have also showed the ascorbyl glucoside enhanced type I collagen synthesis in human fibroblastes (+66%) and decreased melanin synthesis (-56%) in human melanocytes. On the other hand, confocal microscopy revealed that chronic UVA exposure (3 x 12 J/cm2 at 365 nm) strongly induced MMP1 staining in irradiated skin explants. Topical application of the anti-aging formulation containing Snow algae extract, AA2G, AcVitE and VitB3 at 5 mg/cm2 efficiently decreased MMP1 staining and thus protected skin from UVA damage. In conclusion, using different in vitro models of senescence (intrinsic and extrinsic senescence), we demonstrated the anti-aging properties of Snow algae extract, AA2G, AcVitE and VitB3. This results have been confirmed with an ex vivo human skin model of photoaging.

Chronic exposure to ultraviolet (UV) radiation causes oxidative stress, which is involved in photoaging and actinic elastosis. UV and reactive oxygen species generate lipid peroxidation products, including the alpha, beta-unsaturated carbonyl compounds such as acrolein or 4-hydroxynonenal (4-HNE). These aldehydes can modify proteins of the extracellular matrix, but their role in the pathogenesis of photoaging is not clarified. The aim of this study was to investigate whether these aldehydes contribute to alter elastin metabolism and whether topical carbonyl scavengers delay UV-induced skin photoaging. Hairless mice (4-6-week old) daily exposed to UV-A (20 J cm(-2) per day, up to 600 J cm(-2)) exhibited the typical features of photoaging, associated with a significant increase in 4-HNE- and acrolein-adduct content, and elastotic material deposition. Immunofluorescence studies showed the accumulation of 4-HNE adducts on elastin in the dermis of UV-A-exposed mice. This was mimicked in vitro by incubating orceinelastin with 4-HNE or acrolein, which altered its digestion by leukocyte-elastase, a feature possibly involved in the accumulation of elastotic material. A daily topical application of carnosine completely reversed the development of photoaging alterations and 4-HNE-adduct formation on elastin. These data emphasize the role of 4-HNE and acrolein in the mechanism of photoaging, and the preventive effect of carbonyl scavengers.