Mechanisms and treatments of photoaging

Evaluation of the anti-aging potential of acetyl tripeptide-30 citrulline in cosmetics

Acetyl tripeptide-30 citrulline, a commercialized bio-active peptide, is widely used in anti-wrinkle formulations. Volunteer-based tests have demonstrated that topical application of products containing acetyl tripeptide-30 citrulline significantly reduces the visibility of stretch marks. However, there is still a lack of research dedicated to systematically and holistically evaluating its cosmetic properties and elucidating its mechanisms of action. In this study, we assessed the cosmetic potential of acetyl tripeptide-30 citrulline using human immortalized keratinocytes (HaCaT) and mouse embryonic fibroblasts (3T3). Our findings reveal that acetyl tripeptide-30 citrulline exhibits anti-inflammatory and antioxidant activities in skin cells, particularly effective against the inflammatory markers cyclooxygenase-2 (COX2), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6), and the extent of inhibition of reactive oxygen species (ROS) production ranged from 95 % to 340 %. Moreover, acetyl tripeptide-30 citrulline specifically up-regulates Collagen IV and down-regulates matrix metalloproteinase-9 (MMP9), enhances the expression of skin barrier proteins transglutaminase 1 (TGM1) and filaggrin (FLG), thereby demonstrating its reparative capabilities. Additionally, acetyl tripeptide-30 citrulline increases the expression of the water channel protein aquaporin 3 (AQP3), thus improving skin hydration function. These results substantiate the previously proclaimed cosmetic attributes of acetyl tripeptide-30 citrulline and support its efficacy as an anti-aging agent in dermatological applications.

Cosmeceuticals in photoaging: A review

BACKGROUND

Photoaging is a process of the architecture of normal skin damaged by ultraviolet radiation. Topical cosmeceuticals have been used to treat this condition. The authors aimed to understand the mechanism and level of evidence of different commonly used cosmeceuticals used to treat photodamaged skin.

OBJECTIVE

A range of commonly used topical cosmeceuticals (botanicals, peptides, and hydroquinone) has been used in cosmetic medicine for many years to treat photodamaged skin. This review article compares their efficacy and level of evidence.

MATERIAL AND METHODS

This study was a systematic review to evaluate the efficacy of different topical cosmeceuticals. Keywords including "Photoaging," "Azelaic acid," "Soy," "Green Tea," "Chamomile," "Ginkgo," "Tea Tree Oil," "Resveratrol," "Cucumber," "Ginseng," "Centella asiatica," "Licorice Root," "Aloe Vera," "Peptides," "Argireline," "Hydroquinone," were typed on OVID, PUBMED, MEDLINE for relevant studies published on photoaging treatment.

RESULTS

Most of the evidence behind cosmeceuticals is of high-quality ranging from Level I to Level II. In particular, the evidence base behind peptides is the strongest with most studies achieving Level Ib status in the evidence hierarchy.

CONCLUSION

Topical cosmeceuticals like botanicals, peptides and hydroquinone can effectively treat photodamaged skin.

Expression profiles and functional analysis of transfer RNA-derived small RNAs (tsRNAs) in photoaged human dermal fibroblasts

Transfer RNA-derived small RNAs (tsRNAs) refer to a newly established family of non-coding RNAs that regulate a diverse set of biological processes. However, the function of tsRNAs in skin photoaging remains unclear. This research aims to investigate the potential correlation between tsRNAs and skin photoaging. Human dermal fibroblasts (HDFs) were irradiated with UVA at 10 J/cm2 once a day lasting for 14 days, resulting in the establishment of a photoaging model induced by UVA. To identify the expression profiles and functions of tsRNAs, tsRNA sequencing and bioinformatics analysis were conducted. qPCR was employed to validate the results of differentially expressed (DE) tsRNAs. A total of 34 tsRNAs exhibited significant differential expression between the UVA and control groups (n = 3), with nine upregulated and 25 downregulated (log2 fold change >1.5, p-value <0.05). Six tsRNAs were selected at random and validated by qRT-PCR. The enrichment analysis of DE tsRNAs target genes indicated that the dysregulated tsRNAs appeared to be connected with cell cycle, DNA replication and the AGE-RAGE signaling pathway. The expression of tsRNAs was found to be aberrant in UVA-HDF. These findings provide insights into the UVA-induced damage and potential target genes for skin photoaging.

A Comprehensive Review of the Strategies to Reduce Retinoid-Induced Skin Irritation in Topical Formulation

Currently, retinoids are known for their abundant benefits to skin health, ranging from reducing signs of aging and decreasing hyperpigmentation to treating acne. However, it cannot be denied that there are various side effects associated with the use of retinoids on the skin, one of which is irritation. Several approaches can be employed to minimize the irritation caused by retinoids. This review article discusses topical retinoid formulation technology strategies to reduce skin irritation effects. The methodology used in this study is a literature review of 21 reference journals. The sources used in compiling this review are from PubMed, Scopus, ScienceDirect, and MEDLINE. The findings obtained indicate that the following methods can be used to lessen retinoid-induced irritation in topical formulations: developing drug delivery systems in the formulation, such as encapsulating retinoids, transforming retinoids into nanoparticles, forming complexes (e.g., with cyclodextrin), and binding retinoids with carriers (e.g., polymers, NLC, SLN), adding ingredients with anti-irritation activity, skin barrier improvement, and increased skin hydration to retinoid formulations (e.g., combinations of glucosamine, trehalose, ectoine, sucralfate, omega-9, and 4-t-butylcyclohexanol, addition of ethanolic bark extract of Alstonia scholaris R. Br).

Effects of rice fermentation and its bioactive components on UVA-induced oxidative stress and senescence in dermal fibroblasts

Photoaging, caused by ultraviolet (UV) radiation, is characterized by the senescence of skin cells and reduction of collagens. Although rice fermentation is widely used in the cosmetics, its impact on skin photoaging is still not well understood. Herein, we investigated the possible effectiveness of Maifuyin, a fermented rice product, and its components, succinic acid (SA), and choline, for safeguarding UVA-exposed human dermal fibroblasts (HDFs) against photoaging. In this study, the effects of Maifuyin, SA, and choline on UVA-induced cell death and senescence in fibroblasts were evaluated in cell counting kit-8 (CCK-8), expression of β-galactosidase (β-GAL), and matrix metalloproteinases (MMP)-1. To identify oxidative stress, the investigation focused on reactive oxygen species, glutathione, superoxide dismutase, and malondialdehyde. Additionally, a mRNA sequencing technology (RNA-seq) was applied to study the underlying mechanisms of these components on UVA-induced photoaging. Meanwhile, the level of C-X-C motif chemokine ligand 2 (CXCL2) in the cell supernatant was confirmed to assess the autocrine chemokine level. To reassess the involvement of CXCL2, the expression of β-GAL was evaluated in fibroblasts treated with or without CXCL2. The results indicated that 1 mg/mL Maifuyin and SA inhibited UVA-induced senescence in fibroblasts, MMP-1 expression, and oxidative damage. The RNA-seq revealed 1 mg/mL Maifuyin and SA might be recruited chemokine CXCLs to inhibit MMPs production and fibroblast senescence via TNFα, MAPK, and NF-κB pathways. ELISA results showed a significant reduction of autocrine CXCL2 in UVA-irradiated HDFs by pretreating Maifuyin and SA. The β-GAL staining assay revealed that CXCL2 treatment increased β-GAL activity, while the administration of Maifuyin and SA counteracted this effect in HDFs. These results highlighted the potential use of Maifuyin and SA as promising candidates for anti-photoaging applications.

YTHDF2 Regulates Advanced Glycation End Products-Induced Melanogenesis through Inhibiting A20 Expression in Human Dermal Fibroblasts

Fibroblast A20 suppresses advanced glycation end products (AGEs)-induced melanogenesis by inhibiting NLRP3 inflammasome activation. AGEs repress A20 expression and significantly m6A-methylate A20 mRNA in fibroblasts. YTHDF2 is the most studied m6A reader protein and can accelerate degradation of m6A-modified mRNA. Whether YTHDF2 regulates AGEs-induced A20 expression and pigmentation is unknown. In this study, we confirmed that YTHDF2 inversely regulated AGEs-BSA-inhibited A20 expression but facilitated AGEs-BSA-activated NF-κB signaling and NLRP3 inflammasome in fibroblasts via YTHDF2 knockdown and overexpression experiments. Mechanistically, YTHDF2 bound to m6A-modified A20 mRNA induced by AGEs-BSA and increased its degradation. Moreover, fibroblast YTHDF2 robustly promoted AGEs-BSA-induced IL-18 level in coculture supernatants and melanin content, tyrosinase activity, and expression of microphthalmia-associated transcription factor and tyrosinase in melanocytes, which were significantly blocked by IL-18 binding protein. Further, fibroblast YTHDF2 markedly increased AGEs-BSA-induced epidermal melanin level in cocultured ex vivo skin and MAPKs activation in melanocytes. Importantly, upregulated dermal YTHDF2 expression was negatively correlated with dermal A20 level and positively associated with both epidermal melanin and dermal AGEs content in sun-exposed skin and lesions of melasma and solar lentigo. These findings suggest that fibroblast YTHDF2 positively regulates AGEs-induced melanogenesis mainly via A20/ NF-κB /NLRP3 inflammasome/ IL-18 /MAPKs axis in an m6A-dependent manner and functions in photoaging-induced hyperpigmentation skin disorders.

Performance and Safety of Amino-Acid- and Hydroxyapatite Enriched-Hyaluronic Acid Intradermal Gel in Facial Skin Defects

Background and Objectives: The facial skin defects associated with aging are common concerns in the aging population. Hyaluronic-acid-based intradermal gels have established themselves as safe and effective treatments for addressing these concerns. Recently developed enriched products aim to enhance the efficacy of these gels, yet their effectiveness lacks thorough validation in the existing literature. Materials and Methods: In this retrospective analysis, we investigated the outcomes of intradermal gel treatments in 103 patients with soft tissue defects. This study included three groups: 35 patients received amino-acid-enriched hyaluronic acid gel, another 35 were treated with hydroxyapatite-enriched hyaluronic acid gel, and the remaining 33 underwent hyaluronic acid treatment only. The efficacy of the treatments was assessed using the Global Aesthetic Improvement Scale (GAIS) score, while patient satisfaction was gauged through a detailed questionnaire. Any adverse event was monitored. Results: The treatments demonstrated remarkable efficacy, as evidenced by mean GAIS scores of 1.714 points for those treated with amino acid-enriched hyaluronic acid gel, 1.886 points for individuals receiving hydroxyapatite-enriched hyaluronic acid gel, and 1.697 for those treated with hyaluronic acid alone, all showing statistical significance (p < 0.0001). Patient satisfaction was very high. Significantly, there were no recorded instances of major adverse events. Conclusions: Hyaluronic gels, particularly those enriched with amino acids and hydroxyapatite, are effective and safe interventions for addressing facial skin aging defects. They serve as valuable tools in mitigating age-related blemishes and contribute to the overall improvement of skin aesthetics.

Duo photoprotective effect via silica-coated zinc oxide nanoparticles and Vitamin C nanovesicles composites

OBJECTIVE

Zinc Oxide nanoparticles (ZnO NPs) are used widely in nowadays personal care products, especially sunscreens, as a protector against UV irradiation. Yet, they have some reports of potential toxicity. Silica is widely used to cage ZnO NPs to reduce their potential toxicity. Vitamin C derivative, Magnesium Ascorpyl Phosphate (MAP), is a potent antioxidant that can efficiently protect human skin from harmful impacts of UV irradiation and oxidative stress. The combination of silica coated ZnO NPs and MAP nanovesicles could have potential synergistic protective effect against skin photodamage.

METHODS

Silica coated ZnO NPs and MAP nanovesicles (ethosomes and niosomes) were synthesized, formulated, and evaluated as topical gels. These gel formulations were evaluated in mice for their photoprotective effect against UV irradiation through histopathology and immuno-histochemistry study. Split-face clinical study was conducted to compare the effect of application of silica coated ZnO NPs either alone or combined with MAP nanovesicles. Their photoprotective action was evaluated, using Antera 3D® camera, for melanin level, roughness index and wrinkles depth.

RESULTS

Silica coated ZnO NPs when combined with MAP nanovesicles protected mice skin from UV irradiation and decreased the expression of the proinflammatory cytokines, NF-κB. Clinically, silica coated ZnO NPs, alone or combined with MAP nanovesicles, could have significant effect to decrease melanin level, roughness index and wrinkles depth with higher effect for the combination.

CONCLUSION

A composite of silica coated ZnO NPs and MAP nanovesicles could be a promising cosmetic formulation for skin protection against photodamage signs such as hyperpigmentation, roughness, and wrinkles.

Photoaging and cosmeceutical solutions in sun-overexposed countries: The experience of Australia and Brazil

Skin aging is the result of physiological changes determined by genetically driven processes and intrinsic factors, and exacerbated by a combination of multiple environmental factors, the main one being sun exposure. The effects of photoaging are particularly apparent on the face, where the appearance of aging signs can have a significant impact on the emotions conveyed and well-being. Photoprotection and facial skin care for managing photoaging signs are thus of particular importance for both physical and mental health. Countries, like Australia and Brazil, where the level of sun exposure is high and the populations have predominantly outdoor lifestyles, are particularly aware of the harms of photoaging and have implemented several measures to help reduce the risk of skin cancer in their populations. However, sun-seeking behaviours are difficult to change, and it takes time before interventions provide perceptible results. Australia still has some of the highest skin cancer incidence and mortality rates in the world. Solutions that target individuals can also be used for minimizing the clinical signs of facial aging and for improving skin quality, with the ultimate aim being not only to improve the appearance of the skin but also to mitigate the occurrence of pre-malignant and malignant lesions. This review summarizes the features of facial skin photoaging in photo-exposed populations, based on evidence gained from studies of Australian individuals, and discusses the various available solutions for skin photoaging, in particular those that are most popular in Brazil, which is a country with many years of experience in managing photoaged skin.

The effect of tomato and lycopene on clinical characteristics and molecular markers of UV-induced skin deterioration: A systematic review and meta-analysis of intervention trials

Lycopene as a natural antioxidant that have been studied for ultraviolet radiation (UVR) photo protection and is one of the most effective carotenoids to scavenge reactive oxygen species (ROS). This review aims to summarize the protective effect of tomato and lycopene on skin photo damage and skin photoaging in healthy subjects by reviewing the existing population intervention experiments. A total of five electronic databases including PubMed, Scopus, EBSCO, Web of Science and Cochrane Library were searched from inceptions to January 2021 without any restriction. Out of 19336 publications identified, 21 fulfilled the inclusion criteria and were meta-analysis. Overall, interventions supplementing tomato and lycopene were associated with significant reductions in Δa*, MMP-1, ICAM-1 and skin pigmentation; while tomato and lycopene supplementation were associated with significant increase in MED, skin thickness and skin density. Based on the results of this systematic review and meta-analysis, supplementation with tomato and lycopene could reduce skin erythema formation and improve the appearance and pigmentation of the skin, thereby preventing light-induced skin photodamage and skin photoaging. Lycopene-rich products could be used as endogenous sun protection and may be a potential nutraceutical for sun protection.

New Insight into Utilization of Fish By-Product Proteins and Their Skin Health Promoting Effects

In regions reliant on fisheries for livelihoods, a significant number of fish by-products are generated annually due to processing. These discarded parts contain valuable biological resources, such as proteins, fish oils, and trace elements, thus holding enormous potential for reutilization. In recent years, fish by-product proteins have been widely utilized in skincare products due to their rich collagen content, biosafety, and biocompatibility. This review summarizes the research into and applications of fish by-product proteins in skin health, including alleviating oxidative stress and skin inflammation, reducing DNA damage, mitigating melanin production, improving skin hydration, slowing skin matrix degradation, and promoting synthesis. Additionally, the possibility of improving skin health by improving the abundance of gut microbiota is also discussed. This review underscores the importance of fish by-product proteins in the fisheries, food processing, cosmetics, and biomedical industries.

Comparison of five retinoids for anti-photoaging therapy: Evaluation of anti-inflammatory and anti-oxidative activities in vitro and therapeutic efficacy in vivo

Over the past decades, increasing evidences have demonstrated that five retinoids, including retinol (ROL), retinol acetate (RAc), retinol propionate (RP), retinol palmitate (RPalm), and hydroxypinacolone retinoate (HPR), can be potential therapeutic agents for skin photoaging. However, therapeutic efficacies and biosafety have never been compared to these compounds. This study aimed to determine the optimal retinoid type(s) for anti-photoaging therapy both in vitro and in vivo. Our data demonstrated that four retinoids (RPalm, RP, HPR and ROL) but not RAc were effective for anti-photoaging treatment at 5 μg/mL in vitro, with action mechanisms associated with antioxidative, anti-inflammatory and anti-skin ECM degradation activities. Notably, both RPalm and RP appeared superior to HPR and ROL for those activities. Importantly, both RPalm and RP were shown to be optimal for anti-photoaging therapy when topically applied at 5 mg/kg in a UVB-induced mice model of photoaging, which is consistent with their high anti-photoaging activities in vitro. Additionally, topical application of these five retinoids showed satisfactory biosafety without causing significant apoptosis in animal organs, although RP application led to a slight decline in animal body weights. Collectively, these data have laid a good foundation for the next development of the clinical application of these retinoids for skin healthcare.

Preparation of Multifunctional Seaweed Polysaccharides Derivatives Composite Hydrogel to Protect Ultraviolet B-Induced Photoaging In Vitro and In Vivo

Seaweed polysaccharides can be used for protective skin photoaging which is caused by long-term exposure to ultraviolet B (UVB). In this study, a multifunctional composite hydrogel (FACP5) is prepared using sulfated galactofucan polysaccharides, alginate oligosaccharides as active ingredients, and polyacrylonitrile modified κ-Carrageenan as substrate. The properties of FACP5 show that it has good water retention, spreadability, and adhesion. The antiphotoaging activity is evaluated in vitro and in vivo. In vitro experiments demonstrate that the components of FACP5 exhibit good biocompatibility, antioxidant, and anti-tyrosinase activities, and could reduce the cell death rate induced by UVB. In vivo experiments demonstrate that, compared with the mice skin in model group, the skin water content treated with FACP5 increases by 29.80%; the thicknesses of epidermis and dermis decrease by 53.56% and 43.98%, respectively; the activities of catalase and superoxide dismutase increase by 1.59 and 0.72 times, respectively; the contents of interleukin-6 and tumor necrosis factor-α decrease by 19.21% and 17.85%, respectively; hydroxyproline content increases by 32.42%; the expression level of matrix metalloproteinase-3 downregulates by 42.80%. These results indicate that FACP5 has skin barrier repairing, antioxidant, anti-inflammatory, and inhibiting collagen degradation activies, FACP5 can be used as a skin protection remedy for photoaging.

Anti-oxidative, anti-apoptotic, and anti-inflammatory activities of Connarus semidecandrus Jack ethanol extract in UVB-irradiated human keratinocytes

ETHNOPHARMACOLOGICAL RELEVANCE

Connarus semidecandrus Jack (Family: connaraceae) is a medicinal plant known for its wide distribution throughout Southeast Asia. Renowned for its diverse therapeutic properties, it has been traditionally used for treating fever, skin irritation, and colic.

AIM OF THE STUDY

Numerous individuals suffer from skin issues, including wrinkles, hyperpigmentation, and inflammation, due to environmental factors. Although many drugs are available to treat skin problems, chemical drugs have many shortcomings and side effects. Therefore, natural products are attractive potential medicines for alleviating skin troubles. We recently showed that Connarus semidecandrus Jack ethanol extract (Cs-EE) has anti-alopecia potential. This paper aims to explore the potential skin-protective effects and underlying molecular mechanisms of Connarus semidecandrus Jack in UVB-induced human keratinocytes (HaCaT).

MATERIALS AND METHODS

Before utilization, Cs-EE was dissolved in dimethyl sulfoxide (DMSO) and was preserved at a temperature of -20 °C. The phytochemical constituents of Cs-EE were detected by gas chromatography-mass spectrometry analysis (GC-MS). Sequentially, HaCaT cells were exposed to varying concentrations of Cs-EE prior to ultraviolet B (UVB) irradiation. Evaluations of cellular responses in HaCaT cells, including assessments of cell viability, deoxyribonucleic acid (DNA) damage, and gene and protein expressions, were carried out. To explore the specific signaling pathway involved, we conducted a luciferase assay in addition to validating these pathways using Western blot analysis.

RESULTS

Nitric oxide (NO) and intracellular reactive oxygen species were decreased. Melanin production through the activation of melanocytes by α-melanocyte-stimulating hormone (MSH) was also inhibited by Cs-EE. Furthermore, the mRNA expression levels of key factors such as cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), MMP-1, MMP-3, and MMP-9 exhibited a remarkable decrease. In addition, the phosphorylation of TAK1 within the signaling cascade exhibited a decline, and the activities of the transcription factor AP-1 were decreased according to a luciferase reporter assay.

CONCLUSIONS

Taken together, these findings suggest that the anti-inflammatory, anti-aging, and anti-apoptotic effects of Cs-EE indicate the compound's potential usefulness as a natural component in pharmaceutical and cosmetic products.

Oral consumption of Bonito fish-derived elastin peptide (VGPG Elastin® ) improves biophysical properties in aging skin: A randomized, double-blinded, placebo-controlled study

BACKGROUND

Recent in vitro and in vivo studies have suggested that the elastin peptide improves the skin's biophysical properties, enhancing the proliferation of fibroblasts and elastin synthesis, resulting in anti-aging properties. Therefore, we conducted a randomized, double-blinded, placebo-controlled study to clinically evaluate the effect of elastin peptide intake on human skin.

MATERIALS AND METHODS

Healthy adult participants (N = 100) were randomly assigned to receive a test product containing 100 mg of Bonito elastin peptide (VGPG Elastin® ) or placebo. In this study, all participants were Asian from Korea. The parameters of skin wrinkles, hydration, and brightening (melanin index) were measured at baseline and 4, 8, and 12 weeks after intervention.

RESULTS

The average skin roughness, maximum peak-to-valley values, maximum peak height of the wrinkle, maximum valley depth of the wrinkle, average maximum height of the wrinkle, and eye wrinkle volume improved considerably in the test group compared with the placebo after 12 weeks of intervention. Skin hydration was enhanced, and the melanin index was significantly lower in the test group than in the placebo group. No participant experienced adverse events related to the test product.

CONCLUSION

Oral consumption of Bonito elastin peptide (VGPG Elastin®) reduced fine wrinkles, enhanced skin moisture, and decreased melanin index without significant adverse effects and may be a promising anti-wrinkle, anti-dryness, and anti-pigmentation treatment.

Role of autophagy in skin photoaging: A narrative review

As the largest organ of the human body, the skin serves as the primary barrier against external damage. The continuous increase in human activities and environmental pollution has resulted in the ongoing depletion of the ozone layer. Excessive exposure to ultraviolet (UV) radiation enhances the impact of external factors on the skin, leading to photoaging. Photoaging causes physical and psychological damage to the human body. The prevention and management of photoaging have attracted increased attention in recent years. Despite significant progress in understanding and mitigating UV-induced photoaging, the precise mechanisms through which autophagy contributes to the prevention of photoaging remain unclear. Given the important role of autophagy in repairing UV-induced DNA damage and scavenging oxidized lipids, autophagy is considered a novel strategy for preventing the occurrence of photoaging and other UV light-induced skin diseases. This review aims to elucidate the biochemical and clinical features of photoaging, the relationship of skin photoaging and chronological aging, the mechanisms underlying skin photoaging and autophagy, and the role of autophagy in skin photoaging.

Subcutaneous Application of a Gelatin/Hyaluronic Acid Hydrogel Induces the Production of Skin Extracellular Matrix

The development of injectable hydrogels with natural biopolymers such as gelatin (Ge) and hyaluronic acid (Ha) is widely performed due to their biocompatibility and biodegradability. The combination of both polymers crosslinked with N-Ethyl-N'-(3-dimethyl aminopropyl) carbodiimide hydrochloride (EDC) can be used as an innovative dermal filler that stimulates fibroblast activity and increases skin elasticity and tightness. Thus, crosslinked Ge/Ha hydrogels with different concentrations of EDC were administered subcutaneously to test their efficacy in young and old rats. At higher EDC concentrations, the viscosity decreases while the particle size of the hydrogels increases. At all concentrations of EDC, amino and carboxyl groups are present. The histological analysis shows an acute inflammatory response, which disappears seven days after application. At one and three months post-treatment, no remains of the hydrogels are found, and the number of fibroblasts increases in all groups in comparison with the control. In addition, the elastic modulus of the skin increases after three months of treatment. Because EDC-crosslinked Ge/Ha hydrogels are biocompatible and induce increased skin tension, fibroblast proliferation, and de novo extracellular matrix production, we propose their use as a treatment to attenuate wrinkles and expression lines.

Antioxidants in Photoaging: From Molecular Insights to Clinical Applications

Photoaging (PA) is considered a silent disease affecting millions of people globally and is defined as skin damage due to prolonged exposure to ultraviolet radiation (UVR) from the sun. Physiologically, the skin is in a state of renewal and synthesis of components of the extracellular matrix (ECM). However, exposure to UVR affects the production of the ECM, and the functioning and response of skin cells to UVR begins to change, thus expressing clinical and phenotypic characteristics of PA. The primary mechanisms involved in PA are direct damage to the DNA of skin cells, increases in oxidative stress, the activation of cell signaling pathways responsible for the loss of skin integrity, and cytotoxicity. The medical and scientific community has been researching new therapeutic tools that counteract PA, considering that the damage caused by UVR exceeds the antioxidant defense mechanisms of the skin. Thus, in recent years, certain nutraceuticals and phytochemicals have been found to exhibit potential antioxidant and photoprotective effects. Therefore, the main objective of this review is to elucidate the molecular bases of PA and the latest pharmaceutical industry findings on antioxidant treatment against the progression of PA.

Dermatological ultrasound in assessing skin aging

Ultrasonography (US) has emerged as a pivotal tool in Dermatology since its inaugural use in 1979. Its evolution encompasses technological advancements, higher frequencies, and diverse applications in clinical, surgical, and research aspects. The discussion centers on its crucial role in assessing skin aging through various parameters such as skin thickness, subepidermal low echogenicity band (SLEB) characterization, and echogenicity assessment. This analysis can help guide interventions in a more personalized manner for each patient and assess the effectiveness of cosmetics and procedures. Despite its widespread utility, challenges persist, including discrepancies in research outcomes, operator dependence, inability to detect minute lesions, and measurement variations throughout the day. Combining US with complementary methodologies is advocated for a better understanding of skin aging in vivo. The cost-effectiveness and non-invasiveness of the US emphasize its promising future in dermatology, but ongoing research remains imperative to enhance its accuracy and expand its applications.

The skin photoprotective effect of trilinolein: Induction of cellular autophagy via the AMPK-mTOR signaling pathway

Trilinolein (TL) is an active substance contained in traditional Chinese herbs; modern studies have shown that trilinolein has anti-inflammatory and antioxidant effects on the body. This study delves into the photoprotective effect of trilinolein on UVB-irradiated Human Skin Fibroblast (HSF) cells and the underlying mechanisms. Our findings reveal that trilinolein had a photoprotective effect on HSF cells: trilinolein enhanced cellular autophagy, restored UVB-inhibited cell proliferative viability, and curbing UVB-induced reactive oxygen species (ROS) and apoptosis. Intriguingly, after inhibition of TL-induced autophagy via wortmannin, diminished trilinolein's photoprotective effects. Meanwhile, trilinolein was shown to modulate the AMPK-mTOR signaling pathway, thus enhance cellular autophagy in HSF cells, and this tendency was suppressed after the administration of compound C (AMPK inhibitor). In a mouse model of skin photodamage, trilinolein significantly mitigated photodamage extent through morphological and histopathological analyses. This study illuminates trilinolein could inhibit the photodamaging effects of UVB irradiation by regulating cellular autophagy through the AMPK-mTOR signaling pathway, suggesting its promising application in combating UV-induced skin disorders.

Role of reactive oxygen species in ultraviolet-induced photodamage of the skin

Reactive oxygen species (ROS), such as superoxides (O2 •-) and hydroxyl groups (OH·), are short-lived molecules containing unpaired electrons. Intracellular ROS are believed to be mainly produced by the mitochondria and NADPH oxidase (NOX) and can be associated with various physiological processes, such as proliferation, cell signaling, and oxygen homeostasis. In recent years, many studies have indicated that ROS play crucial roles in regulating ultraviolet (UV)-induced photodamage of the skin, including exogenous aging, which accounts for 80% of aging. However, to the best of our knowledge, the detailed signaling pathways, especially those related to the mechanisms underlying apoptosis in which ROS are involved have not been reviewed previously. In this review, we elaborate on the biological characteristics of ROS and its role in regulating UV-induced photodamage of the skin.

Advances in the Applications of Extracellular Vesicle for the Treatment of Skin Photoaging: A Comprehensive Review

Skin photoaging is a complex biological process characterized by the accumulation of oxidative damage and structural changes in the skin, resulting from chronic exposure to ultraviolet (UV) radiation. Despite the growing demand for effective treatments, current therapeutic options for skin photoaging remain limited. However, emerging research has highlighted the potential of extracellular vesicles (EVs), including exosomes, micro-vesicles, apoptotic bodies and liposomes, as promising therapeutic agents in skin rejuvenation. EVs are involved in intercellular communication and can deliver bioactive molecules, including proteins, nucleic acids, and lipids, to recipient cells, thereby influencing various cellular processes. This comprehensive review aims to summarize the current research progress in the application of EVs for the treatment of skin photoaging, including their isolation and characterization methods, roles in skin homeostasis, therapeutic potential and clinical applications for skin photoaging. Additionally, challenges and future directions in EVs-based therapies for skin rejuvenation are discussed.

Long Non-coding RNA H19-Overexpressing Exosomes Ameliorate UVB-Induced Photoaging by Upregulating SIRT1 Via Sponging miR-138

UVB-induced photoaging is characterized by wrinkle formation, slackness and senile plaques, affecting the health and beauty of human being. Our previous study revealed that exosomes derived from adipose-derived stem cells (ADSCs) could efficiently alleviate UVB-induced photodamage. However, the functional ingredients in exosomes were undefined. LncRNA H19, one of the well-researched lncRNAs in exosomes, exhibits multiple physiological effects. This study aims to demonstrate the photo-protective role of lncRNA H19 on skin photoaging in UVB-irradiated human skin fibroblasts cells (HSFs) and Kunming mice. LncRNA H19-overexpressing exosomes (H19-Exo) were isolated from the supernatant of ADSCs infected with lncRNA H19-loaded lentivirus. The results showed that H19-Exo significantly inhibited MMPs production, DNA damage and ROS generation while enhancing procollagen type I synthesis in UVB-irradiated HSFs. Meanwhile, H19-Exo markedly reversed epidermal thickening and collagen degradation in UVB-irradiated mice. Furthermore, luciferase reporter assays indicated that lncRNA H19 acted as a sponge for miR-138 expression, and SIRT1 was targeted by miR-138. Evidence from both in vitro and in vivo studies also revealed that H19-Exo could enhance SIRT1 expression by knocking down miR-138. In conclusion, lncRNA H19 served as a therapeutic candidate in treating UVB-induced skin photoaging by upregulation of SIRT1 via miR-138.

The extract from Portulaca oleracea L. rehabilitates skin photoaging via adjusting miR-138-5p/Sirt1-mediated inflammation and oxidative stress

Photoaging is the main form of external skin aging, and ultraviolet radiation is the main cause. Long-term ultraviolet radiation can cause oxidative stress, inflammation, immune responses, and skin cell apoptosis. Therefore, it is necessary to explore active products from plants to treat skin photoaging. C57BL/6J mice were randomly divided into control, model, and purslane (Portulaca oleracea L.) extract-treated groups (150, 300, and 600 mg/kg). Ultraviolet (UV) radiation induces skin photoaging. Histopathological changes in the skin were observed by hematoxylin and eosin (H&E), Masson's trichrome, and toluidine staining. Levels of hydroxyproline (HYP), hyaluronic acid (HA), collagen I (COL1), catalase (CAT), malondialdehyde (MDA), and total superoxide dismutase (T-SOD) were measured. UVB-induced BJ and HaCaT cells were used to evaluate the effects of the crude extract. The effects of the purslane extract on miR-138-5p/Sirt1 signaling were then tested. The results showed that the purslane extract significantly increased cell viability in UVB-induced cells and decreased oxidative damage and inflammation. In addition, the extract affected the miR-138-5p levels in vivo and in vitro, and increased the levels of the target gene Sirt1. In UVB-induced cells, purslane extract significantly altered the expression levels of genes or proteins associated with miR-138-5p/Sirt1 signaling. Inflammation and oxidative damage were significantly enhanced when miR-138-5p was overexpressed, and the expression levels of the genes and proteins were reversed by the extract. Co-transfection with the miR-138-5p inhibitor and si-Sirt1 showed the same effects as the extract on the signal. Similar results have been observed in mice. In summary, purslane extract showed potent protective effects against skin photoaging by regulating the miR-138-5p/Sirt1 axis and should be used as a natural product for skin care.

Single-Walled Carbon Nanotube-Guided Topical Skin Delivery of Tyrosinase to Prevent Photoinduced Damage

When the skin is exposed to ultraviolet radiation (UV), it leads to the degradation of the extracellular matrix (ECM) and results in inflammation. Subsequently, melanocytes are triggered to induce tyrosinase-mediated melanin synthesis, protecting the skin. Here, we introduce a proactive approach to protect the skin from photodamage via the topical delivery of Streptomyces avermitilis-derived tyrosinase (SaTy) using single-walled carbon nanotube (SWNT). Utilizing a reverse electrodialysis (RED) battery, we facilitated the delivery of SaTy-SWNT complexes up to depths of approximately 300 μm, as analyzed by using confocal Raman microscopy. When applied to ex vivo porcine skin and in vivo albino mouse skin, SaTy-SWNT synthesized melanin, resulting in 4-fold greater UV/vis absorption at 475 nm than in mice without SaTy-SWNT. The synthesized melanin efficiently absorbed UV light and alleviated skin inflammation. In addition, the densification of dermal collagen, achieved through SaTy-mediated cross-linking, reduced photoinduced wrinkles by 66.3% in the affected area. Our findings suggest that SWNT-mediated topical protein delivery holds promise in tissue engineering applications.

Balsam Poplar Buds Extracts-Loaded Gels and Emulgels: Development, Biopharmaceutical Evaluation, and Biological Activity In Vitro

Balsam poplar buds have been used for wound healing and treating irritated skin in traditional medicine. Balsam poplar buds extracts exhibit anti-inflammatory, antioxidant, and antimicrobial effects. In recent years, scientific research has begun to validate some of these traditional uses, leading to an increased interest in balsam poplar buds as a potential source of natural remedies in modern medicine. The study aims to simulate semi-solid pharmaceutical forms with balsam poplar buds extract and evaluate their quality through biopharmaceutical research. The active compounds identified in Lithuanian poplar buds were p-coumaric acid, cinnamic acid, caffeic acid, galangin, pinocembrin, pinobanksin, and salicin. In gels, pH values ranged from 5.85 ± 0.05 to 5.95 ± 0.07. The determined pH values of emulgels ranged from 5.13 ± 0.05 to 5.66 ± 0.15. After 6 h, the release of active compounds from gels and emulgels ranged from 47.40 ± 2.41% to 71.17 ± 3.54. p-coumaric acid dominates in the balsam poplar buds extracts. The pH values of the prepared sem-solid pharmaceutical forms are suitable for use on the skin. The viscosity of the formulations depends on the amount of gelling agent. All formulations showed antioxidant activity. It is relevant to conduct a more extensive study on the influence of the chosen carrier on the release of active compounds from semi-solid formulations with an extract of balsam poplar buds.

Study on the Antioxidant Effect of Shikonin-Loaded β-Cyclodextrin Forming Host-Guest Complexes That Prevent Skin from Photoaging

When the skin is overexposed to ultraviolet rays, free radicals will accumulate in the skin, causing lipid damage and even inducing photoaging of the skin. Combination therapy with antioxidant drugs is a good choice for topical treatment of skin photoaging due to its special physiological structure. In this paper, shikonin was encapsulated in β-cyclodextrin (SH-β-CD) by the precipitation crystallization method, which delayed the release of the drug and increased drug solubility. The average diameter of SH-β-CD was 203.0 ± 21.27 nm with a zeta potential of -14.4 ± 0.5 mV. The encapsulation efficiency (EE%) was 65.9 ± 7.13%. The results of the in vitro permeation across the dialysis membrane and ex vivo transdermal release rates were 52.98 ± 1.21% and 88.25 ± 3.26%, respectively. In vitro antioxidant and antilipid peroxidation model assay revealed the antioxidant potential of SH and SH-β-CD. In the mice model of skin photoaging, SH and SH-β-CD had a recovery effect on the skin damage of mice, which could significantly increase the superoxide dismutase (SOD) activity in the skin. Briefly, SH-β-CD had an obvious therapeutic effect on the skin photoaging of mice caused by UV, and it is promising in skin disease treatment and skin care.

Protective Effect of Mycosporine-like Amino Acids Isolated from an Antarctic Diatom on UVB-Induced Skin Damage

Although it is well recognized that mycosporine-like amino acids (MAAs) are ultraviolet (UV) protective agents that can reduce UV damage, the specific biological mechanism of its role in the skin remains unclear. In this study, we investigated the effect of MAAs extracted from Antarctic diatom Phaeodactylum tricornutum ICE-H on UVB-induced skin damage using a mice model. The MAAs components identified by liquid chromatography-tandem mass spectrometry included 4-deoxygadusol, shinorine, and porphyra-334, which were purified using a Supledean Carboxen1000 solid phase extraction column. The antioxidant activities of these MAA compounds were tested in vitro. For UVB-induced skin photodamage in mice, MAAs alleviated skin swelling and epidermal thickening in this study. We detected the content of reactive oxygen species (ROS), malondialdehyde, and collagen in skin tissue. In addition, quantitative real-time polymerase chain reaction was used to detect nuclear factor-κB (NF-κB), tumor necrosis factor α, interleukin-1β, cyclooxygenase-2, mitogen activated protein kinase (MAPK) family (extracellular signal-regulated kinase, c-Jun amino-terminal kinase, and p38 kinase), and matrix metalloproteinases. The expression of these cytokines and enzymes is related to inflammatory responses and collagen degradation. In comparison to the model group without MAA treatment, the MAA component decreased the concentration of ROS, the degree of oxidative stress in the skin tissue, and the expression of genes involved in the NF-κB and MAPK pathways. In summary, these MAA components extracted from Phaeodactylum tricornutum ICE-H protected against UVB-induced skin damage by inhibiting ROS generation, relieving skin inflammation, and slowing down collagen degradation, suggesting that these MAA components are effective cosmetic candidate molecules for the protection and therapy of UVB damage.

Exosomes as cutting-edge therapeutics in various biomedical applications: An update on engineering, delivery, and preclinical studies

Exosomes are cell-derived nanovesicles, circulating in different body fluids, and acting as an intercellular mechanism. They can be purified from culture media of different cell types and carry an enriched content of various protein and nucleic acid molecules originating from their parental cells. It was indicated that the exosomal cargo can mediate immune responses via many signaling pathways. Over recent years, the therapeutic effects of various exosome types were broadly investigated in many preclinical studies. Herein, we present an update on recent preclinical studies on exosomes as therapeutic and/or delivery agents for various applications. The exosome origin, structural modifications, natural or loaded active ingredients, size, and research outcomes were summarized for various diseases. Overall, the present article provides an overview of the latest exosome research interests and developments to clear the way for the clinical study design and application.

The hyaluronan metabolism in the UV-irradiated human epidermis and the relevance of in vitro epidermal models

Exposure to the sun affects the skin and may eventually result in UV-induced skin damage. It is generally known that hyaluronan (HA) is one of the main structural and functional components of the skin. However, UV-related changes in the HA metabolism in the skin have not yet been elucidated. Using qRT-PCR, confocal microscopy and LC-MS/MS we compared the naturally sun-exposed (SE), sun-protected, experimentally repeatedly UVA + UVB-exposed and acutely (once) UVA + UVB irradiated skin of Caucasian women. The epidermis was harvested by means of suction blistering 24 h after the acute irradiation. In addition, the epidermis was compared with a UV-irradiated in vitro reconstituted 3D epidermis (EpiDerm) and an in vitro 2D culture of normal human keratinocytes (NHEK). The amount of HA was found to be statistically significantly enhanced in the acutely irradiated epidermis. The acute UV evinced the upregulation of HA synthases (HAS2 and HAS3), hyaluronidases (HYAL2 and HYAL3), Cluster of differentiation 44 (CD44), and Cell Migration Inducing Proteins (CEMIP and CEMIP2), while only certain changes were recapitulated in the 3D epidermis. For the first time, we demonstrated the enhanced gene and protein expression of CEMIP and CEMIP2 following UV irradiation in the human epidermis. The data suggest that the HA metabolism is affected by UV in the irradiated epidermis and that the response can be modulated by the underlying dermis.

Microalgae Microneedle Supplies Oxygen for Antiphotoaging Treatment

UV exposure often triggers photoaging of the skin. Pharmacological treatment suffers from severe side effects as well as poor efficacy because of insufficient skin penetration. Dissolved oxygen has been previously shown to reverse photoaged skin; however, the treatment is often limited by the availability of equipment (e.g., high-pressure oxygen). Poor oxygen diffusion into the skin has also limited its therapeutic efficacy. Herein, we developed a microneedle patch to deliver living microalgae to the deeper layers of the skin for efficient oxygenation and reversal of photoaging. The continuous release of oxygen from microalgae in the skin through photosynthesis reversed the inflammatory microenvironment and reduced reactive oxygen species levels in the photodamaged skin, leading to collagen regeneration and reduced wrinkles. This study provides not only a means for highly efficient skin oxygenation and reversal of photoaging but also an important theoretical basis for the clinical treatment of photoaging.

Research progress of extracellular vesicles and exosomes derived from mesenchymal stem cells in the treatment of oxidative stress-related diseases

There is growing evidence that mesenchymal stem cell-derived extracellular vesicles and exosomes can significantly improve the curative effect of oxidative stress-related diseases. Mesenchymal stem cell extracellular vesicles and exosomes (MSC-EVs and MSC-Exos) are rich in bioactive molecules and have many biological regulatory functions. In this review, we describe how MSC-EVs and MSC-Exos reduce the related markers of oxidative stress and inflammation in various systemic diseases, and the molecular mechanism of MSC-EVs and MSC-Exos in treating apoptosis and vascular injury induced by oxidative stress. The results of a large number of experimental studies have shown that both local and systemic administration can effectively inhibit the oxidative stress response in diseases and promote the survival and regeneration of damaged parenchymal cells. The mRNA and miRNAs in MSC-EVs and MSC-Exos are the most important bioactive molecules in disease treatment, which can inhibit the apoptosis, necrosis and oxidative stress of lung, heart, kidney, liver, bone, skin and other cells, and promote their survive and regenerate.

In Vitro and In Vivo Efficacy of Topical Dosage Forms Containing Self-Nanoemulsifying Drug Delivery System Loaded with Curcumin

The external use of curcumin is rare, although it can be a valuable active ingredient in the treatment of certain inflammatory diseases. The aim of our experimental work was to formulate topical dosage forms containing curcumin for the treatment of atopic dermatitis. Curcumin has extremely poor solubility and bioavailability, so we have tried to increase it with the usage of self-emulsifying drug delivery systems. Creams and gels were formulated using penetration-enhancing surfactants and gelling agents. The release of the drug from the vehicle and its penetration through the membrane were determined using a Franz diffusion cell. An MTT cytotoxicity and in vitro antioxidant assays were performed on HaCaT cell line. The in vivo anti-inflammatory effect of the preparations was tested by measuring rat paw edema. In addition, we examined the degree of inflammation induced by UV radiation after pretreatment with the cream and the gel on rats. For the gels containing SNEDDS, the highest penetration was measured after half an hour, while for the cream, it took one hour to reach the maximum concentration. The gel containing Pemulen TR-1 showed the highest drug release. It was determined that the curcumin-containing preparations can be safely applied on the skin and have antioxidant effects. The animal experiments have proven the effectiveness of curcumin-containing topical preparations.

Ultraviolet light induces mechanical and structural changes in full thickness human skin

While the detrimental health effects of prolonged ultraviolet (UV) irradiation on skin health have been widely accepted, the biomechanical process by which photoaging occurs and the relative effects of irradiation with different UV ranges on skin biomechanics have remained relatively unexplored. In this study, the effects of UV-induced photoageing are explored by quantifying the changes in the mechanical properties of full-thickness human skin irradiated with UVA and UVB light for incident dosages up to 1600 J/cm2. Mechanical testing of skin samples excised parallel and perpendicular to the predominant collagen fiber orientation show a rise in the fractional relative difference of elastic modulus, fracture stress, and toughness with increased UV irradiation. These changes become significant with UVA incident dosages of 1200 J/cm2 for samples excised both parallel and perpendicular to the dominant collagen fiber orientation. However, while mechanical changes occur in samples aligned with the collagen orientation at UVB dosages of 1200 J/cm2, statistical differences in samples perpendicular to the collagen orientation emerge only for UVB dosages of 1600 J/cm2. No notable or consistent trend is observed for the fracture strain. Analyses of toughness changes with maximum absorbed dosage reveals that no one UV range is more impactful in inducing mechanical property changes, but rather these changes scale with maximum absorbed energy. Evaluation of the structural characteristics of collagen further reveals an increase in collagen fiber bundle density with UV irradiation, but not collagen tortuosity, potentially linking mechanical changes to altered microstructure.

Photoaging and Topical Rejuvenation

Photoaging is a complex process of skin changes associated with chronic ultraviolet exposure. Prevention with photoprotection and treatment with topical retinoids are the core components of a topical antiaging regimen. Other topicals such as hydroquinone, vitamin C, niacinamide, and alpha hydroxyl acid can be added based on specific concerns. However, caution must be used with some of these products as the stability and absorption are major considerations. A simple topical regimen will reduce irritability and enhance compliance.

A Comparative Study of Skin Changes in Different Species of Mice in Chronic Photoaging Models

This study aimed to design a novel mouse model of chronic photoaging. We used three different species of mice (C57BL/6J, ICR, and KM) to create a chronic photoaging model of the skin. The irradiation time was gradually increased for 40 consecutive days. The skins of the mice were removed on day 41 and subjected to staining to observe them for morphological changes. Immunohistochemistry was used to detect tumor necrosis factor-α (TNF-α) and p53 expression; superoxide dismutase (SOD) and malondialdehyde (MDA) were measured as well. Compared with C57BL/J mice, which showed hyperpigmentation, the irradiated skin of ICR and KM mice showed more obvious skin thickening and photoaging changes of the collagen and elastic fibers. KM mice had higher levels of inflammation, oxidative stress, and senescent cells. Compared with the 5-month-old KM mice, the photoaging changes of the 9-month-old KM mice were more pronounced, the SOD values were lower, and the MDA values were higher. In summary, KM mice have higher levels of abnormal elastic fibers, inflammation, cellular senescence, and oxidative stress than ICR mice, and are more suitable for studies related to chronic skin photoaging. C57BL/6J mice were found to be suitable for studies related to skin pigmentation due to photoaging.

The Mechanism of Peach Gum Polysaccharide Preventing UVB-Induced Skin Photoaging by Regulating Matrix Metalloproteinanse and Oxidative Factors

Exposure to ultraviolet light can cause oxidative damage and accelerate skin aging and is one of the main causes of skin aging. Peach gum polysaccharide (PG) is a natural edible plant component that has many biological activities, such as regulating blood glucose and blood lipids and improving colitis, as well as antioxidant and anticancer properties. However, there are few reports on the antiphotoaging effect of peach gum polysaccharide. Therefore, in this paper, we study the basic composition of the raw material peach gum polysaccharide and its ability to improve UVB-induced skin photoaging damage in vivo and in vitro. The results show that peach gum polysaccharide is mainly composed of mannose, glucuronic acid, galactose, xylose, and arabinose, and its molecular weight (Mw) is 4.10 × 10⁶ g/mol. The results of the in vitro cell experiments show that PG could significantly alleviate UVB-induced apoptosis of human skin keratinocytes, promote cell growth repair, reduce the expression of intracellular oxidative factors and matrix metal collagenase, and improve the extent of oxidative stress repair. Moreover, the results from the in vivo animal experiments showed that PG could not only effectively improve the phenotype of UVB-induced photoaged skin in model mice but also significantly improve their oxidative stress status, regulate the contents of ROS and the levels of SOD and CAT, and repair the oxidative skin damage induced by UVB in vivo. In addition, PG improved UVB-induced photoaging-mediated collagen degradation in mice by inhibiting the secretion of matrix metalloproteinases. The above results indicate that peach gum polysaccharide has the ability to repair UVB-induced photoaging and may be used as a potential drug and antioxidant functional food to resist photoaging in the future.

Antiphotoaging Effect of AGEs Blocker™ in UVB-Irradiated Cells and Skh:HR-1 Hairless Mice

Chronic exposure to ultraviolet (UV) radiation is a major cause of photoaging. It involves extrinsic aging, wrinkle formation, and skin dehydration, and leads to excessive production of active oxygen that adversely affects the skin. Here, we investigated the antiphotoaging effect of AGEs Blocker^TM (AB), which comprises Korean mint aerial part and fig and goji berry fruits. Compared to its individual components, AB was more potent at increasing the expression of collagen and hyaluronic acid and decreasing MMP-1 expression in UVB-irradiated Hs68 fibroblasts and HaCaT keratinocytes. In Skh:HR-1 hairless mice exposed to 60 mJ/cm² UVB for 12 weeks, oral administration of 20 or 200 mg/kg/day AB restored skin moisture by improving UVB-induced erythema, skin moisture, and transepidermal water loss, and alleviated photoaging by improving UVB-induced elasticity and wrinkles. Moreover, AB upregulated the mRNA levels of hyaluronic acid synthase and collagen-related Col1a1, Col3a1, and Col4a1 genes, increasing hyaluronic acid and collagen expression, respectively. AB inhibited UVB-induced MAPK and AP-1 (c-fos) activation, resulting in significantly downregulated expression of MMP-1 and -9, which are responsible for collagen degradation. AB also stimulated the expression and activity of antioxidative enzymes and reduced lipid peroxidation. Thus, AB is a potential preventive and therapeutic agent for photoaging.

Photoaging: Reversal of the Oxidative Stress Through Dietary Changes and Plant-Based Products

Redox flagging represents all life processes, and maintaining a physiological level of antioxidants is essential for the legitimate working of the cell. Genetics and environmental triggers are two major culminating factors for skin aging, both chronological and photoaging. The latter, however, relies principally upon the level of ultraviolet radiation (UVR) exposure and the skin phototype. Apart from causing DNA damage, UVR also stimulates the receptors present in keratinocytes as well as fibroblasts. This in turn leads to the breakdown of collagen and a breach in the generation of new collagen. It is speculated that the breakdown of collagen in the dermis is ensured by the defective restoration that ultimately hampers the structural integrity of skin, leading to wrinkled and atrophic skin. The skin has an admixture of various endogenous antioxidants that work synergistically with vitamins and minerals to maintain cellular equilibrium. Although, their role in safeguarding the cells against the detrimental effects induced by UVR is still questionable and requires further research. However, the advancement in the biology of skin has led to the development of strategies that aim at skin rejuvenation and retarding the progression of photoaging and its visible signs. Photoaging in this article is reviewed in light of current concepts in pathogenesis and its prevention. In addition, the article focuses on both prevailing and forthcoming treatment strategies primarily through plant-based products that will help slow down the process of photoaging.

Association of Early Clinical Response to Laser Rejuvenation of Photoaged Skin with Increased Lipid Metabolism and Restoration of Skin Barrier Function

Laser resurfacing treatments for photoaged skin have improved dramatically over the past decades, but few studies have examined the molecular mechanisms underlying differences in clinical response. Seventeen white female participants with moderate-to-severe photoaging received nonablative fractional laser treatment on the face and forearm once monthly for 6 months. Biopsies for microarray analysis were performed at baseline and 7 days after facial treatment and at baseline and 1, 7, 14, and 29 days after forearm treatment in each participant, resulting in 119 total samples. Participants were stratified into fast (n = 11) and slow (n = 6) responders on the basis of the presence of clinical improvement after the first treatment. Microarray analysis revealed the upregulation of genes associated with matrix metalloproteinases, collagen and extracellular components, TGF-β signaling, double-stranded RNA signaling, and retinoic acid synthesis after treatment that did not differ significantly between fast and slow responders. Cluster and enrichment analyses suggested significantly greater activation of lipid metabolism and keratinocyte differentiation in fast responders, who showed greater upregulation of acyltransferases, fatty acid elongases, fatty acid 2-hydroxylase, fatty acid desaturases, and specific keratins that may contribute to epidermal barrier function. These results create, to our knowledge, a previously unreported atlas of molecular changes that correlate with improvements in photoaging after laser therapy.

Molecular basis of skin photoaging and therapeutic interventions by plant-derived natural product ingredients: A comprehensive review

Skin areas exposed to ultraviolet radiation (UV) from sunlight are more prone to photoaging than unexposed areas evidenced by several signs which include skin dryness, irregular pigmentation, lentigines, hyperpigmentation, wrinkling, and decreased elasticity. Plant-based natural product ingredients with therapeutic potential against skin photoaging are gaining more attention. This article aims the reviewing the research work done in exploring the cellular and molecular mechanisms involved in UV-induced skin photoaging, followed by summarizing the mechanistic insights involved in its therapeutics by natural product-based ingredients. In the mechanistic section of the convoluted procedure of photoaging, we described the effect of UV radiation (UVR) on different cellular macromolecules (direct damage) and subsequently, the deleterious consequences of UVR-generated reactive oxygen species (indirect damage) and signaling pathways activated or inhibited by UV induced ROS generation in various cellular pathologies of skin photoaging like inflammation, extracellular matrix degradation, apoptosis, mitochondrial dysfunction, and immune suppression. We also discussed the effect of UV radiation on the adipose tissue, and transient receptor potential cation channel V of photoaging skin. In the past few decades, mechanistic studies performed in this area have deciphered various therapeutic targets, opening avenues for different available therapeutic options against this pathological condition. So the remaining portion of the review deals with various natural product-based therapeutic agents available against skin photodamage.

Low-energy green light alleviates senescence-like phenotypes in a cell model of photoaging

BACKGROUND

Ultraviolet B (UVB) affects diverse pathways in skin cells, resulting in skin photoaging. Skin fibroblasts internalize and degrade elastin and collagen, playing prominent roles in photoaging. Green light is used in many fields of dermatology, but few studies have examined its role in photoaging. The present work aimed to assess low-energy green light for its effects in a previously proposed cell model of photoaging and to explore the possible anti-photoaging mechanism.

METHODS

The stress-induced premature senescence (SIPS) model was constructed via repeated treatment of MDFs with UVB. Senescence-like phenotypes were compared among normal, low-energy green light pretreatment and UVB groups, for example, cell morphological properties, senescence-associated β-galactosidase (SA-β-gal) amounts, extracellular matrix (ECM) biosynthesis and degradation, and autophagy.

RESULTS

In comparison with the UVB group, the green light pretreatment group showed significantly decreased number of senescent mast cells and markedly declined signal intensity and amounts of SA-β-gal-positive cells. Furthermore, green light pretreatment directly affected ECM by increasing type I and type III collagen production and decreasing MMP-1 amounts. Moreover, changes in autophagy levels induced by green light pretreatment provided a potential mechanism underlying its anti-aging property.

CONCLUSIONS

Low-energy green light pretreatment improves senescence-like phenotypes in vitro, indicating a possible application for anti-aging in clinic after future research has uncovered the potential mechanism.

Combined Transcriptomic and Proteomic Analyses Reveal the Different Responses to UVA and UVB Radiation in Human Keratinocytes

Ultraviolet (UV) radiation from sunlight is a major risk factor for many cutaneous pathologies including skin aging and cancers. Despite decades of research, the different responses to UVA and UVB in human keratinocytes have not been systemically investigated. Here, we performed multi-omics to characterize the common and different changes in gene transcription and protein expression after exposure to UVB and UVA, respectively. Keratinocyte cells, treated with or without UV, were analyzed by TMT-labeled MS/MS spectra and RNA-sequencing. A common set of genes/proteins was found to be impacted by both UVA and UVB and the other differential genes/proteins showed wavelength specificity. The common set of genes/proteins were mainly involved in keratinization, lipid metabolic processes and stimulus response. The UVB specifically responsive genes/proteins were mainly related to RNA processing, gene silencing regulation and cytoskeleton organization. The UVA specifically responsive genes/proteins were mainly involved in vesicle-mediated transport and oxygen-containing compound response. Meanwhile, the hub differential genes/proteins in each set were identified by protein-protein interaction networks and cluster analysis. This work provided a global view of the similar and differential molecular mechanisms of UVB- and UVA-induced cell damage in keratinocytes, which would be beneficial for further studies in the prevention or treatment of UV-related pathologies.

δ-Catenin Requirement in Keratinocyte Proliferation and DNA Repair Identifies a Therapeutic Target for Photoaging

Skin photoaging is a complicated pathological process and is mainly due to UV irradiation, especially UVB irradiation. Damage induction by UVB is a complex process, involving intricate molecular mechanisms. The formation of bulky photoproducts in the DNA globally affects transcription and splicing and results in the dysfunction of keratinocytes. In this study, we show that δ-catenin is predominantly distributed in keratinocytes of the skin epidermis and functionally accelerates cell proliferation and DNA repair. Ex vivo protein profiling reveals that δ-catenin upregulates the phosphorylation of RSK2^Ser-227 by enhancing the interaction between PDK1 and RSK2 and thereby induces the nuclear accumulation of YB1 to promote proliferation and DNA repair. Moreover, δ-catenin overexpression induces in vivo keratinocyte proliferation and DNA repair in UVB-irradiated mouse skin. Notably, acidic fibroblast GF/FGFR1 is identified as one of the key upstream signalings of δ-catenin by inducing δ-catenin stabilization. The involvement of δ-catenin in keratinocyte proliferation and DNA repair may suggest δ-catenin as a target for the treatment of UVB damage.

Immunomodulation in age-related disorders and nanotechnology interventions

Recently, the aging population has increased exponentially around the globe bringing more challenges to improve quality of life in those populations while reducing the economic burden on healthcare systems. Aging is associated with changes in the immune system culminating in detrimental effects such as immune dysfunction, immunosenescence, and chronic inflammation. Age-related decline of immune functions is associated with various pathologies including cardiovascular, autoimmune, neurodegenerative, and infectious diseases to name a few. Conventional treatment addresses the onset of age-related diseases by early detection of risk factors, administration of vaccines as preventive care, immunomodulatory treatment, and other dietary supplements. However, these approaches often come with systemic side-effects, low bioavailability of therapeutic agents, and poor outcomes seen in the elderly. Recent innovations in nanotechnology have led to the development of novel biomaterials/nanomaterials, which explore targeted drug delivery and immunomodulatory interactions in vivo. Current nanotechnology-based immunomodulatory approaches that have the potential to be used as therapeutic interventions for some prominent age-related diseases are discussed here. Finally, we explore challenges and future aspects of nanotechnology in the treatments of age-related disorders to improve quality of life in the elderly. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Cardiovascular Disease Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Ethyl Acetate Extract of Marine Algae, Halymenia durvillei, Provides Photoprotection against UV-Exposure in L929 and HaCaT Cells

Halymenia durvillei is a red alga distributed along the coasts of Southeast Asian countries including Thailand. Previous studies have shown that an ethyl acetate fraction of H. durvillei (HDEA), containing major compounds including n-hexadecanoic acid, 2-butyl-5-hexyloctahydro-1H-indene, 3-(hydroxyacetyl) indole and indole-3-carboxylic acid, possesses high antioxidant and anti-lung cancer activities. The present study demonstrated that HDEA could protect mouse skin fibroblasts (L929) and human immortalized keratinocytes (HaCaT) against photoaging due to ultraviolet A and B (UVA and UVB) by reducing intracellular reactive oxygen species (ROS) and expressions of matrix metalloproteinases (MMP1 and MMP3), as well as increasing Nrf2 nuclear translocation, upregulations of mRNA transcripts of antioxidant enzymes, including superoxide dismutase (SOD), heme oxygenase (HMOX) and glutathione S-transferase pi1 (GSTP1), and procollagen synthesis. The results indicate that HDEA has the potential to protect skin cells from UV irradiation through the activation of the Nrf2 pathway, which leads to decreasing intracellular ROS and MMP production, along with the restoration of skin collagen.

Ultraviolet Radiation Protective and Anti-Inflammatory Effects of Kaempferia galanga L. Rhizome Oil and Microemulsion: Formulation, Characterization, and Hydrogel Preparation

Long-term UV radiation exposure can induce skin disorders such as cancer and photoallergic reactions. Natural products have been considered as non-irritate and potential sunscreen resources due to their UV absorption and anti-inflammatory activities. This study aimed to evaluate the in vitro ultraviolet radiation protective effect and anti-inflammatory activity of K. galanga rhizome oil and microemulsions. The chemical components of K. galanga rhizome oil was analyzed via gas chromatography coupled with mass spectrometry. Microemulsions containing K. galanga rhizome oil were formulated using a phase-titration method. The microemulsion was characterized for droplet size, polydispersity index, and zeta potential, using a dynamic light-scattering technique. The physical and chemical stability of the microemulsion were evaluated via a dynamic light scattering technique and UV-Vis spectrophotometry, respectively. The UV protection of K. galanga rhizome oil and its microemulsion were investigated using an ultraviolet transmittance analyzer. The protective effect of K. galanga rhizome oil against LPS-induced inflammation was investigated via MTT and nitric oxide inhibitory assays. In addition, a hydrogel containing K. galanga rhizome oil microemulsion was developed, stored for 90 days at 4, 30, and 45 °C, and characterized for viscosity, rheology, and pH. The chemical degradation of the main active compound in the microemulsion was analyzed via UV-Vis spectrophotometry. The formulated O/W microemulsion contained a high loading efficiency (101.24 ± 2.08%) of K. galanga rhizome oil, suggesting a successful delivery system of the oil. The size, polydispersity index, and zeta potential values of the microemulsion were optimized and found to be stable when stored at 4, 30, and 45 °C. K. galanga rhizome oil and microemulsion demonstrated moderate sun protective activity and reduced the nitric oxide production induced by LPS in macrophage cells, indicating that microemulsion containing K. galanga rhizome oil may help protect human skin from UV damage and inflammation. A hydrogel containing K. galanga rhizome oil microemulsion was developed as a topical preparation. The hydrogel showed good physical stability after heating and cooling cycles and long-term storage (3 months) at 4 °C. The use of K. galanga rhizome oil as a natural sun-protective substance may provide a protective effect against inflammation on the skin. K. galanga rhizome oil microemulsion was successfully incorporated into the hydrogel and has the potential to be used as a topical sunscreen preparation.

Beneficial Effect of Gastrodia elata Blume and Poria cocos Wolf Administration on Acute UVB Irradiation by Alleviating Inflammation through Promoting the Gut-Skin Axis

Bioactive compounds in some herbs can, directly and indirectly, protect against photoaging. We evaluated the effects of Gastrodia elata Blume (GE) and Poria cocos Wolf (PC) water extracts on ultraviolet (UV) B-induced skin lesions by acute UVB exposure in ICR mice and explored their mechanism of action. After removing the hair on the back of the mice, UVB (280-310 nm) was exposed to the back for 30 min to induce skin damage. Four UVB exposure groups were divided into the following according to the local application (1,3-butanediol extract) on the dorsal skin and oral intake (0.3 g water extract/kg body weight/day): 1,3-butanediol and cellulose(control; UV-Con), retinoic acid (positive-control; UV-Positive), PC extracts (UV-PC), and GE extracts (UV-GE). The fifth group had no UVB exposure with the same treatment as the UV-Con (Normal-control). The erythema, burns, erosion, and wounds of the UV-PC and UV-PC groups were alleviated, and the most significant improvements occurred in the UV-PC group. PC and GE reduced the thickness of the dorsal skin tissue, the penetration of mast cells, and malondialdehyde contents. The mRNA expression of TNF-α, IL-13, and IL-4, inflammatory factors, were also reduced significantly in the dorsal skin of the UV-PC and UV-GE groups. UV-PC, UV-GE, and UV-Positive showed improvements in UV-induced intestinal tissue inflammation. UV-Con deteriorated the intestinal morphology, and PC and GE alleviated it. The α-diversity of the fecal microbiota decreased in the UV-control, and UV-PC and UV-GE prevented the decrease. Fecal metagenome analysis revealed increased propionate biosynthesis in the UV-PC group but decreased lipopolysaccharide biosynthesis in the UV-PC and UV-GE groups compared to UV-Con. In conclusion, the local application and intake of PC and GE had significant therapeutic effects on acute UV-induced skin damage by reducing oxidative stress and proinflammatory cytokines, potentially promoting the gut-microbiota-gut-skin axis.

Uncovering Streptomyces-Derived Compounds as Cosmeceuticals for the Development of Improved Skin Photoprotection Products: An In Silico Approach to Explore Multi-Targeted Agents

The search for novel photoprotective substances has become a challenge in cosmeceutical research. Streptomyces-derived compounds can serve as a promising source of photoprotective agents to formulate skin photoprotection products, such as sunscreens. This study aimed to identify specialized metabolites with the potential to modulate UV-induced cellular damage in the skin by identifying potential multi-target-directed ligands. Using a combination of ligand- and target-based virtual screening approaches, a public compound library comprising 6524 Streptomyces-derived specialized metabolites was studied for their photoprotective capability. The compounds were initially filtered by safety features and then examined for their ability to interact with key targets in the photodamage pathway by molecular docking. A set of 50 commercially available UV filters was used as the benchmark. The protein–ligand stability of selected Streptomyces-derived compounds was also studied by molecular dynamics (MD) simulations. From the compound library, 1981 compounds were found to meet the safety criteria for topically applied products, such as low skin permeability and low or non-toxicity-alerting substructures. A total of 34 compounds had promising binding scores against crucial targets involved in UV-induced photodamage, such as serotonin-receptor subtype 5-HT2A, platelet-activating factor receptor, IL-1 receptor type 1, epidermal growth factor receptor, and cyclooxygenase-2. Among these compounds, aspergilazine A and phaeochromycin F showed the highest ranked interactions with four of the five targets and triggered complex stabilization over time. Additionally, the predicted UV-absorbing profiles also suggest a UV-filtering effect. Streptomyces is an encouraging biological source of compounds for developing topical products. After in silico protein–ligand interactions, binding mode and stabilization of aspergilazine A and phaeochromycin F led to the discovery of potential candidates as photodamage multi-target inhibitors. Therefore, they can be further explored for the formulation of skin photoprotection products.