Photoaging

Deciphering the role of skin aging in pigmentary disorders

Skin aging is a complex biological process involving intrinsic and extrinsic factors. Skin aging contains alterations at the tissue, cellular, and molecular levels. Currently, there is increasing evidence that skin aging occurs not only in time-dependent chronological aging but also plays a role in skin pigmentary disorders. This review provides an in-depth analysis of the impact of skin aging on different types of pigmentary disorders, including both hyperpigmentation disorders such as melasma and senile lentigo and hypopigmentation disorders such as vitiligo, idiopathic guttate hypomelanosis and graying of hair. In addition, we explore the mechanisms of skin aging on pigmentation regulation and suggest several potential therapeutic approaches for skin aging and aging-related pigmentary disorders.

Fermented Fish Collagen Diminished Photoaging-Related Collagen Decrease by Attenuating AGE-RAGE Binding Activity

Ultraviolet (UV) irradiation causes skin wrinkles and decreases elasticity. UV also increases binding between advanced glycation end products (AGEs) and the receptor for AGEs (RAGE), resulting in increased inflammation and activation of NF-κB. We evaluated whether fermented fish collagen (FC) could decrease photoaging via decreasing AGE-RAGE binding activity, which was associated with decreased TNF-α and NF-κB levels in UV-irradiated keratinocytes and animal skin. In the UV-irradiated keratinocytes, AGE-RAGE binding activity and TNF-α secretion levels were increased, and FC decreased these. Additionally, AGE-RAGE binding activity and TNF-α secretion levels were attenuated by soluble RAGE (RAGE inhibitor) in the UV-irradiated keratinocytes. FC decreased AGE-RAGE binding activity, TNF-α levels, and translocation of NF-κB in the UV-irradiated skin. Furthermore, FC decreased the expression of matrix metalloproteinases 1/3/9, which degrades collagen fibers, and Smad7, which inhibits Smad2/3, in UV-irradiated skin. FC increased Smad2/3 and collagen fiber accumulation. FC also increases skin moisture and elasticity. In conclusion, FC could attenuate skin photoaging via decreasing AGE-RAGE binding activity and its downstream signals such as TNF-α and NF-κB.

A subset of human dermal fibroblasts overexpressing Cockayne syndrome group B protein resist UVB radiation-mediated premature senescence

Ultraviolet B (UVB) radiation is a major contributor to skin photoaging. Although mainly absorbed by the epidermis, UVB photons managing to penetrate the upper dermis affect human dermal fibroblasts (HDFs), leading, among others, to the accumulation of senescent cells. In vitro studies have shown that repeated exposures to subcytotoxic UVB radiation doses provoke HDFs' premature senescence shortly after the end of the treatment period. Here, we found that repetitive exposures to non-cytotoxic UVB radiation doses after several days lead to mixed cultures, containing both senescent cells and fibroblasts resisting senescence. "Resistant" fibroblasts were more resilient to a novel intense UVB radiation stimulus. RNA-seq analysis revealed that ERCC6, encoding Cockayne syndrome group B (CSB) protein, is up-regulated in resistant HDFs compared to young and senescent cells. CSB was found to be a key molecule conferring protection toward UVB-induced cytotoxicity and senescence, as siRNA-mediated CSB loss-of-expression rendered HDFs significantly more susceptible to a high UVB radiation dose, while cells from a CSB-deficient patient were found to be more sensitive to UVB-mediated toxicity, as well as senescence. UVB-resistant HDFs remained normal (able to undergo replicative senescence) and non-tumorigenic. Even though they formed a distinct population in-between young and senescent cells, resistant HDFs retained numerous tissue-impairing characteristics of the senescence-associated secretory phenotype, including increased matrix metalloprotease activity and promotion of epidermoid tumor xenografts in immunodeficient mice. Collectively, here we describe a novel subpopulation of HDFs showing increased resistance to UVB-mediated premature senescence while retaining undesirable traits that may negatively affect skin homeostasis.

Ultraviolet Light Causes Skin Cell Senescence: From Mechanism to Prevention Principle

The skin is an effective protective barrier that significantly protects the body from damage caused by external environmental factors. Furthermore, skin condition significantly affects external beauty. In today's era, which is of material and spiritual prosperity, there is growing attention on skincare and wellness. Ultraviolet radiation is one of the most common external factors that lead to conditions like sunburn, skin cancer, and skin aging. In this review, several mechanisms of UV-induced skin cell senescence are discussed, including DNA damage, oxidative stress, inflammatory response, and mitochondrial dysfunction, which have their own characteristics and mutual effects. As an illustration, mitochondrial dysfunction triggers electron evasion and the generation of more reactive oxygen species, leading to oxidative stress and the activation of the NLRP3 inflammasome, which in turn causes mitochondrial DNA (mt DNA) damage. Based on the current mechanism, suitable prevention and treatment strategies are proposed from sunscreen, dietary, and experimental medications respectively, aimed at slowing down skin cell aging and providing protection from ultraviolet radiation. The effects of ultraviolet rays on skin is summarized, offering insights and directions for future studies on mechanism of skin cell senescence, with an anticipation of discovering more effective prevention and cure methods.

The Redefinition and Volumization of the Lip Area with Hyaluronic Acid: A Case Series

Background: The increasing popularity of non-surgical cosmetic enhancements for the lower face and perioral area, particularly through hyaluronic acid (HA) fillers, reflects the growing desire for improved lip volume and definition. This study showcases the effects of a specific HA filler on lip fullness, shape, and overall perioral rejuvenation. Methods: We conducted a retrospective single-site observational analysis of adult female patients treated with Genefill Soft Fill HA injections in the lips and perioral areas. Both patient and physician satisfaction were evaluated using the Likert scale and Global Aesthetic Improvement Scale (GAIS), respectively. The outcomes for natural appearance, volume, and durability were assessed using a five-point scale. The patients were followed up with for up to six months to monitor any adverse events. Results: The cohort included thirteen female patients with an average age of 55.3 ± 8.3 years. Approximately 1.2 ± 0.4 mL of filler was used per patient. The results indicate high satisfaction, with scores above 4 for naturalness, volume, and durability. Over 92% of patients reported a significant improvement in appearance. No moderate or severe adverse events were reported. Conclusions: Genefill Soft Fill HA filler is both effective and safe for enhancing lip esthetics, with high satisfaction rates among recipients and no significant adverse events observed.

Resveratrol activates autophagy and protects from UVA-induced photoaging in human skin fibroblasts and the skin of male mice by regulating the AMPK pathway

Skin photoaging is mostly caused by ultraviolet A (UVA), although active medications to effectively counteract UVA-induced photoaging have not yet been created. Resveratrol, a naturally occurring polyphenol found in the skin of grapes, has been shown to have various biological functions such as anti-inflammatory and antioxidant characteristics. However, the role of resveratrol in UVA-induced photoaging has not been clarified. We investigated the mechanism of action of resveratrol by UVA irradiation of human skin fibroblasts (HSF) and innovatively modified a mouse model of photoaging. The results demonstrated that resveratrol promoted AMP-activated protein kinase (AMPK) phosphorylation to activate autophagy, reduce reactive oxygen species (ROS) production, inhibit apoptosis, and restore normal cell cycle to alleviate UVA-induced photoaging. In addition, subcutaneous injection of resveratrol not only improved the symptoms of roughness, erythema, and increased wrinkles in the skin of UVA photodamaged mice, but also alleviated epidermal hyperkeratosis and hyperpigmentation, reduced inflammatory responses, and inhibited collagen fiber degradation. In conclusion, our studies proved that resveratrol can treat UVA-induced photoaging and elucidated the possible molecular mechanisms involved, providing a new therapeutic strategy for future anti-aging.

New Insights into the Role of PPARγ in Skin Physiopathology

Peroxisome proliferator-activated receptor gamma (PPARγ) is a transcription factor expressed in many tissues, including skin, where it is essential for maintaining skin barrier permeability, regulating cell proliferation/differentiation, and modulating antioxidant and inflammatory responses upon ligand binding. Therefore, PPARγ activation has important implications for skin homeostasis. Over the past 20 years, with increasing interest in the role of PPARs in skin physiopathology, considerable effort has been devoted to the development of PPARγ ligands as a therapeutic option for skin inflammatory disorders. In addition, PPARγ also regulates sebocyte differentiation and lipid production, making it a potential target for inflammatory sebaceous disorders such as acne. A large number of studies suggest that PPARγ also acts as a skin tumor suppressor in both melanoma and non-melanoma skin cancers, but its role in tumorigenesis remains controversial. In this review, we have summarized the current state of research into the role of PPARγ in skin health and disease and how this may provide a starting point for the development of more potent and selective PPARγ ligands with a low toxicity profile, thereby reducing unwanted side effects.

Adjuvant PD-1 Checkpoint Inhibition in Early Cutaneous Melanoma: Immunological Mode of Action and the Role of Ultraviolet Radiation

Melanoma ranks as the fifth most common solid cancer in adults worldwide and is responsible for a significant proportion of skin-tumor-related deaths. The advent of immune checkpoint inhibition with anti-programmed death protein-1 (PD-1) antibodies has revolutionized the adjuvant treatment of high-risk, completely resected stage III/IV melanoma. However, not all patients benefit equally. Current strategies for improving outcomes involve adjuvant treatment in earlier disease stages (IIB/C) as well as perioperative treatment approaches. Interfering with T-cell exhaustion to counteract cancer immune evasion and the immunogenic nature of melanoma is key for anti-PD-1 effectiveness. Yet, the biological rationale for the efficacy of adjuvant treatment in clinically tumor-free patients remains to be fully elucidated. High-dose intermittent sun exposure (sunburn) is a well-known primary risk factor for melanomagenesis. Also, ultraviolet radiation (UVR)-induced immunosuppression may impair anti-cancer immune surveillance. In this review, we summarize the current knowledge about adjuvant anti-PD-1 blockade, including a characterization of the main cell types most likely responsible for its efficacy. In conclusion, we propose that local and systemic immunosuppression, to some extent UVR-mediated, can be restored by adjuvant anti-PD-1 therapy, consequently boosting anti-melanoma immune surveillance and the elimination of residual melanoma cell clones.

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.

Sex- and age-dependent skin mechanics-A detailed look in mice

Skin aging is of immense societal and, thus, scientific interest. Because mechanics play a critical role in skin's function, a plethora of studies have investigated age-induced changes in skin mechanics. Nonetheless, much remains to be learned about the mechanics of aging skin. This is especially true when considering sex as a biological variable. In our work, we set out to answer some of these questions using mice as a model system. Specifically, we combined mechanical testing, histology, collagen assays, and two-photon microscopy to identify age- and sex-dependent changes in skin mechanics and to relate them to structural, microstructural, and compositional factors. Our work revealed that skin stiffness, thickness, and collagen content all decreased with age and were sex dependent. Interestingly, sex differences in stiffness were age induced. We hope our findings not only further our fundamental understanding of skin aging but also highlight both age and sex as important variables when conducting studies on skin mechanics. STATEMENT OF SIGNIFICANCE: Our work addresses the question, "How do sex and age affect the mechanics of skin?" Answering this question is of both scientific and societal importance. We do so in mice as a model system. Thereby, we hope to add clarity to a body of literature that appears divided on the effect of both factors. Our findings have important implications for those studying age and sex differences, especially in mice as a model system.

Suppression of UVB-Induced MMP-1 Expression in Human Skin Fibroblasts Using Lysate of Lactobacillus iners Derived from Korean Women's Skin in Their Twenties

The process of skin aging is intricate, involving intrinsic aging, influenced by internal factors, and extrinsic aging, mainly caused by exposure to UV radiation, resulting in photoaging. Photoaging manifests as skin issues such as wrinkles and discoloration. The skin microbiome, a diverse community of microorganisms on the skin's surface, plays a crucial role in skin protection and can be affected by factors like humidity and pH. Probiotics, beneficial microorganisms, have been investigated for their potential to enhance skin health by regulating the skin microbiome. This can be accomplished through oral probiotics, impacting the gut-skin axis, or topical applications introducing live bacteria to the skin. Probiotics mitigate oxidative stress, suppress inflammation, and maintain the skin's extracellular matrix, ultimately averting skin aging. However, research on probiotics derived from human skin is limited, and there is no established product for preventing photoaging. The mechanism by which probiotics shield the skin microbiome and skin layers from UV radiation remains unclear. Recently, researchers have discovered Lactobacillus in the skin, with reports indicating a decrease in this microorganism with age. In a recent study, scientists isolated Lactobacillus iners KOLBM20 from the skin of individuals in their twenties and confirmed its effectiveness. A comparative analysis of genetic sequences revealed that strain KOLBM20 belongs to the Lactobacillus genus and closely relates to L. iners DSM13335(T) with a 99.20% similarity. Importantly, Lactobacillus iners KOLBM20 displayed anti-wrinkle properties by inhibiting MMP-1. This investigation demonstrated the inhibitory effect of KOLBM20 strain lysate on MMP-1 expression. Moreover, the data suggest that KOLBM20 strain lysate may prevent UVB-induced MMP-1 expression by inhibiting the activation of the ERK, JNK, and p38 signaling pathways induced by UVB. Consequently, KOLBM20 strain lysate holds promise as a potential therapeutic agent for preventing and treating skin photoaging.

Glutathione amino acid precursors protect skin from UVB-induced damage and improve skin tone

BACKGROUND

UV radiation exposure causes skin irritation, erythema, darkening and barrier disruption by inducing oxidative stress and inflammation. Glutathione, a master antioxidant, plays an important role in the antioxidant defence network of the skin.

OBJECTIVE

This study aimed to assess the in vitro protective effects of the glutathione amino acid precursors blend (GAP) on transcriptomic and phenotypic endpoints against UVB-induced challenges.

METHODS

Normal human epidermal melanocytes (NHEMs) were exposed to GAP, ascorbic acid (AA) and its derivatives. Viability was assessed using the CCK8 method. Melakutis®, a pigmented living skin equivalent (pLSE) model, underwent repeated 50 mJ/cm2 UVB irradiation with or without GAP treatment. Images of the model were captured with consistent camera parameters, and the model's light intensity was measured using a spectrophotometer. Melanin content was determined by measuring absorbance at 405 nm. Confirmation of melanin deposition and distribution was achieved through Fontana-Masson staining. Transcriptomic analysis was conducted using RNA sequencing (RNA-Seq), and a machine learning approach was employed for transcriptomic aging clock analysis.

RESULTS

In NHEMs, all tested compounds exhibited over 85% viability compared to the vehicle control, indicating no heightened risk of cytotoxicity. Notably, GAP demonstrated greater efficacy in inhibiting melanin production than AA derivatives at equivalent concentrations. In pLSE models, GAP notably enhanced model lightness, and reduced melanin content and deposition following the UVB challenge, whereas AA showed minimal impact. GAP effectively counteracted UVB-induced alterations in gene expression linked to pigmentation, inflammation and aging. Moreover, recurrent UVB exposure substantially elevated the biological age of pLSE models, a phenomenon mitigated by GAP treatment.

CONCLUSIONS

In NHEMs, GAP exhibited enhanced effectiveness in inhibiting melanin production at identical tested doses in comparison to AA derivatives. Noteworthy protective effects of GAP against UVB irradiation were observed in the pLSE models, as evidenced by skin pigmentation measurements and transcriptomic changes.

Functionally similar genes exhibit comparable/similar time-course expression kinetics in the UV-induced photoaged mouse model

Skin photoaging induced by ultraviolet (UV) irradiation contributes to the formation of thick and coarse wrinkles. Humans are exposed to UV light throughout their lives. Therefore, it is crucial to determine the time-sequential effects of UV on the skin. In this study, we irradiated the mouse back skin with UV light for eight weeks and observed the changes in gene expressions via microarray analysis every week. There were more downregulated genes (514) than upregulated genes (123). The downregulated genes had more functional diversity than the upregulated genes. Additionally, the number of downregulated genes did not increase in a time-dependent manner. Instead, time-dependent kinetic patterns were observed. Interestingly, each kinetic cluster harbored functionally enriched gene sets. Since collagen changes in the dermis are considered to be a major cause of photoaging, we hypothesized that other gene sets contributing to photoaging would exhibit kinetics similar to those of the collagen-regulatory genes identified in this study. Accordingly, co-expression network analysis was conducted using 11 well-known collagen-regulatory seed genes to predict genes with similar kinetics. We ranked all downregulated genes from 1 to 504 based on their expression levels, and the top 50 genes were suggested to be involved in the photoaging process. Additionally, to validate and support our identified top 50 gene lists, we demonstrated that the genes (FN1, CCDC80, PRELP, and TGFBR3) we discovered are downregulated by UV irradiation in cultured human fibroblasts, leading to decreased collagen levels, which is indicative of photoaging processes. Overall, this study demonstrated the time-sequential genetic changes in chronically UV-irradiated skin and proposed 50 genes that are involved in the mechanisms of photoaging.

Mesenchymal stem cell-derived exosomes and skin photoaging: From basic research to practical application

BACKGROUND

Skin photoaging is a condition caused by long-term exposure to ultraviolet irradiation, resulting in a variety of changes in the skin, such as capillary dilation, increased or absent pigmentation, dryness, sagging, and wrinkles. Stem cells possess a remarkable antioxidant capacity and the ability to proliferate, differentiate, and migrate, and their main mode of action is through paracrine secretion, with exosomes being the primary form of secretion. Stem cell-derived exosomes contain a variety of growth factors and cytokines and may have great potential to promote skin repair and delay skin ageing.

METHODS

This review focuses on the mechanisms of UV-induced skin photoaging, the research progress of stem cell exosomes against skin photoaging, emerging application approaches and limitations in the application of exosome therapy.

RESULT

Exosomes derived from various stem cells have the potential to prevent skin photoaging.

CONCLUSION

The combination with novel materials may be a key step for their practical application, which could be an important direction for future basic research and practical applications.

Research on Circular RNA Expression Profiles in the Photoaging Mouse Model

Background

Nude mouse has been widely used to study photoaging induced by long-term chronic UV exposure. Circular RNAs (circRNAs) have been previously identified in several diseases. However, the roles of circRNAs in photoaging and potential regulatory mechanisms remain unclear.

Objectives

To identify specific circRNAs differentially expressed in photoaged skin and investigate their potential role in aging.

Materials and Methods

In this study, we screened out the microarray data to profile the expression of circRNAs. The circRNAs were analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) biological pathway.

Results

36 circRNAs were identified to be differentially expressed between the UV group and control group (fold change > 1.5; P < 0.05), including 6 upregulated and 30 downregulated circRNAs. GO and KEGG biological pathway analyses indicated that the changes in circRNAs were associated with cancer, inflammation, oxidative stress, and metabolism.

Conclusions

This present study revealed a circRNAs expression profiling in vivo. These findings not only provide a new possibility to prevent the occurrence of photoaging but also have therapeutic values for photoaging and associated skin diseases.

A systematic review and meta-analysis of efficacy, safety, and satisfaction rates of laser combination treatments vs laser monotherapy in skin rejuvenation resurfacing

Laser therapies have been well-established in ameliorating skin-aging consequences. This systematic review aims to determine the efficacy, safety profile, and satisfaction rates of laser combination therapies on skin rejuvenation resurfacing. A systematic search was performed in four major databases up to September 2022. Skin rejuvenation studies were eligible comprising at least one laser combination arm, inclusive of all laser types (ablative or non-ablatives), and one monotherapy arm selected from one of the combined modalities. Studies combining one laser modality with radiofrequency (RF) or intense pulse light (IPL) were also assessed. Trials that did not encompass a monotherapy control arm were evaluated independently as single-arm studies. Eighteen clinical trials recruiting 448 cases were included after screening. A total of 532 nm KTP + 1064 nm Nd:YAG and 2940 nm Er:YAG + Nd:YAG were the two most utilized laser combinations and exerted higher improvements and milder adverse events, compared to their monotherapy in most studies. Combining CO2 with rhodamine-IPL or gallium arsenide laser increased efficacy and satisfaction and brings about faster skin recovery time. Augmenting CO2 + RF did not increase improvement vs CO2 laser alone but prolonged skin erythema. Our meta-analysis revealed the pooled prevalence of quartile improvement rates as 0%, 28%, 40%, 27% in laser combination group, and 0%, 9%, 31%, 17% in laser monotherapy group, respectively. The satisfaction within each quartile category was 39%, 25%, 15%, 7% in laser combination and 20%, 25%, 16%, 17% in laser monotherapy, respectively, suggestive of the higher efficacy and satisfaction of laser combination group. The pain scores were lower in laser combination group than monotherapy (4.8 ± 1.18 vs 7.18 ± 0.7, converted on a scale of 0 to 10). Post-laser skin erythema lasted less longer in the combination group (12.8 vs 15.24 days). Laser combination therapies were discovered to be superior to their monotherapies in terms of clinical improvement rates, diminished adverse events such as pain and erythema and patients satisfaction rates. Due to paucity of high-quality reportings, additional trials are warranted to corroborate these results.

Skin Cancer Microenvironment: What We Can Learn from Skin Aging?

Aging is a natural intrinsic process associated with the loss of fibrous tissue, a slower cell turnover, and a reduction in immune system competence. In the skin, the continuous exposition of environmental factors superimposes extrinsic damage, mainly due to ultraviolet radiation causing photoaging. Although not usually considered a pathogenic event, photoaging affects cutaneous biology, increasing the risk of skin carcinogenesis. At the cellular level, aging is typified by the rise of senescence cells a condition characterized by reduced or absent capacity to proliferate and aberrant hyper-secretory activity. Senescence has a double-edged sword in cancer biology given that senescence prevents the uncontrolled proliferation of damaged cells and favors their clearance by paracrine secretion. Nevertheless, the cumulative insults and the poor clearance of injured cells in the elderly increase cancer incidence. However, there are not conclusive data proving that aged skin represents a permissive milieu for tumor onset. On the other hand, tumor cells are capable of activating resident fibroblasts onto a pro-tumorigenic phenotype resembling those of senescent fibroblasts suggesting that aged fibroblasts might facilitate cancer progression. This review discusses changes that occur during aging that can prime neoplasm or increase the aggressiveness of melanoma and non-melanoma skin cancer.

Endogenous Photosensitizers in Human Skin

Endogenous photosensitizers play a critical role in both beneficial and harmful light-induced transformations in biological systems. Understanding their mode of action is essential for advancing fields such as photomedicine, photoredox catalysis, environmental science, and the development of sun care products. This review offers a comprehensive analysis of endogenous photosensitizers in human skin, investigating the connections between their electronic excitation and the subsequent activation or damage of organic biomolecules. We gather the physicochemical and photochemical properties of key endogenous photosensitizers and examine the relationships between their chemical reactivity, location within the skin, and the primary biochemical events following solar radiation exposure, along with their influence on skin physiology and pathology. An important take-home message of this review is that photosensitization allows visible light and UV-A radiation to have large effects on skin. The analysis presented here unveils potential causes for the continuous increase in global skin cancer cases and emphasizes the limitations of current sun protection approaches.

Photoprotective Effect of Fermented and Aged Mountain-Cultivated Ginseng Sprout (Panax ginseng) on Ultraviolet Radiation-Induced Skin Aging in a Hairless Mouse Model

Interest in foods that promote inner beauty increases with increases in exposure to ultraviolet (UV) rays and with improvements in quality of life. This study was performed to evaluate the efficacy of fermented and aged mountain-cultivated ginseng sprouts (FAMCGSs), which have higher anti-inflammatory and antioxidant effects compared to mountain-cultivated ginseng sprouts (MCGSs), as an inner beauty enhancing food. The effect of orally administered FAMCGSs on UV type B (UVB) radiation-induced skin aging was investigated in a hairless mouse model through analyzing skin parameters including epidermal thickness, transepidermal water loss (TEWL), roughness, moisture, elasticity, and collagen contents. The mice exposed to UVB had markedly greater epidermal thickness, TEWL, and skin roughness than those of the normal control (NC) group. In addition, the levels of collagen, skin moisture, and dermal elasticity were lower in the UVB radiation group than the NC group. These UVB-induced skin aging parameters were significantly lower in the groups administered FAMCGSs than in the groups not administered FAMCGSs (p < 0.05). These results show that FAMCGSs exhibit a photoprotective effect in mice exposed to UVB and suggest that FAMCGSs can be used as a food that promotes inner beauty and protects skin from UVB-induced photoaging.

Rutin Protects Fibroblasts from UVA Radiation through Stimulation of Nrf2 Pathway

This study explores the photoprotective effects of rutin, a bioflavonoid found in some vegetables and fruits, against UVA-induced damage in human skin fibroblasts. Our results show that rutin increases cell viability and reduces the high levels of ROS generated by photo-oxidative stress (1 and 2 h of UVA exposure). These effects are related to rutin’s ability to modulate the Nrf2 transcriptional pathway. Interestingly, activation of the Nrf2 signaling pathway results in an increase in reduced glutathione and Bcl2/Bax ratio, and the subsequent protection of mitochondrial respiratory capacity. These results demonstrate how rutin may play a potentially cytoprotective role against UVA-induced skin damage through a purely antiapoptotic mechanism.

Use of Natural Agents and Agrifood Wastes for the Treatment of Skin Photoaging

Photoaging is the premature aging of the skin caused by repeated exposure to ultraviolet (UV) rays. The harmful effects of UV rays-from the sun or from artificial sources-alter normal skin structures and cause visible damage, especially in the most exposed areas. Fighting premature aging is one of the most important challenges of the medical landscape. Additionally, consumers are looking for care products that offer multiple benefits with reduced environmental and economic impact. The growing requests for bioactive compounds from aromatic plants for pharmaceutical and cosmetic applications have to find new sustainable methods to increase the effectiveness of new active formulations derived from eco-compatible technologies. The principle of sustainable practices and the circular economy favor the use of bioactive components derived from recycled biomass. The guidelines of the European Commission support the reuse of various types of organic biomass and organic waste, thus transforming waste management problems into economic opportunities. This review aims to elucidate the main mechanisms of photoaging and how these can be managed using natural renewable sources and specific bioactive derivatives, such as humic extracts from recycled organic biomass, as potential new actors in modern medicine.

α-Ionone protects against UVB-induced photoaging in epidermal keratinocytes

Objective

To evaluate whether α-ionone, an aromatic compound mainly found in raspberries, carrots, roasted almonds, fruits, and herbs, inhibits UVB-mediated photoaging and barrier dysfunction in a human epidermal keratinocyte cell line (HaCaT cells).

Methods

The anti-photoaging effect of α-ionone was evaluated by detecting the expression of barrier-related genes and matrix metalloproteinases (MMPs) in HaCaT cells. The levels of reactive oxygen species, oxidation product, antioxidant enzyme, and inflammatory factors were further analysed to underline the protective effect of α-ionone on epidermal photoaging.

Results

It was found that α-ionone attenuated UVB-induced barrier dysfunction by reversing keratin 1 and filaggrin in HaCaT cells. α-Ionone also reduced the protein amount of MMP-1 and mRNA expression of MMP-1 and MMP-3 in UVB-irradiated HaCaT cells, implying protective effects on extracellular matrix. Furthermore, HaCaT cells exposed to α-ionone showed significant decreases in interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor-α as compared to UVB-irradiated HaCaT cells. α-Ionone treatment significantly inhibited the UVB-induced intracellular reactive oxygen species increase and malondialdehyde accumulation. Therefore, the beneficial effects of α-ionone on inhibiting MMPs secretion and barrier damage may be related to attenuated inflammation and oxidative stress.

Conclusion

Our results highlight the protective effects of α-ionone on epidermal photoaging and promote its clinic application as a potential natural anti-photodamage agent in future.

TAZ Reduces UVA-mediated Photoaging through Regulates Cell Proliferation in Skin Fibroblasts

The transcriptional co-activator with PDZ-binding motif (TAZ) is a significant transcription factor downstream of the Hippo pathway regulating organ size, tissue regeneration, cell proliferation and apoptosis. Here, we report on TAZ in response to photoaging mediated by repeated UVA irradiation in skin fibroblasts. Continuous UVA irradiation caused a decrease in TAZ and targeted CTGF mRNA and protein expression in fibroblasts, accompanied by reduced cell proliferation, DNA damage, and cell cycle arrest in G1 phase and S phase reduction. Furthermore, P16 and P21 expression levels were increased, whereas Lamin B1 and Lamin A/C expression were decreased as a result of repeated UVA exposure. We further demonstrated that TAZ reduction enables photoaging caused by continuously UVA-irradiated fibroblasts. TAZ overexpression decreases G1 phase, augments the S phase and reduces P16 and P21 protein expression levels in fibroblasts. However, TAZ overexpressing cells exposed to chronic-UVA radiation show induced G1 phase arrest, an S phase reduction, and elevated P16 and P21 protein levels in fibroblasts, compared with TAZ overexpression cells. These findings suggest a novel function of TAZ to reduce photoaging in fibroblasts. This regulation implies that TAZ might be a viable therapeutic target for photoaging or UVA-related skin disorders.

Limonene protects human skin keratinocytes against UVB-induced photodamage and photoaging by activating the Nrf2-dependent antioxidant defense system

Long term exposure to solar ultraviolet B (UVB) radiation is one of the primary factors of premature skin aging and is referred to as photoaging. Also, mammalian skin exposed to UVB triggers an increase in production of α-melanocyte-stimulating hormone (α-MSH), which is critically involved in the pathogenesis of hyperpigmentary skin diseases. This study investigated the protective effect of limonene on UVB-induced photodamage and photoaging in immortalized human skin keratinocytes (HaCaT) in vitro. Initially, we determined cell viability and levels of reactive oxygen species (ROS) in UVB-irradiated HaCaT cells. Pretreatment with limonene increased cell viability followed by inhibition of intracellular ROS generation in UVB-irradiated HaCaT cells. Interestingly, the antioxidative activity of limonene was directly correlated with an increase in expression of endogenous antioxidants, including heme oxygenase 1 (HO-1), NAD(P)H:quinone oxidoreductase 1 (NQO-1), and γ-glutamylcysteine synthetase (γ-GCLC), which was associated with enhanced nuclear translocation and activation of NF-E2-related factor-2 (Nrf2). Indeed, Nrf2 knockdown reduced limonene's protective effects. Additionally, we observed that limonene treatment inhibited UVB-induced α-MSH secretion followed by inhibition of proopiomelanocortin (POMC) via suppression of p53 transcriptional activation. Moreover, limonene prevented UVB-mediated depletion of tight junction regulatory proteins, including occludin and zonula occludens-1. On the other hand, limonene treatment significantly decreased matrix metalloproteinase-2 levels in UVB-irradiated HaCaT cells. Based on these results, limonene may have a dermato-protective effect in skin cells by activating the Nrf2-dependent cellular antioxidant defense system.

Asterias pectinifera-Derived Collagen Peptides Mixed with Halocynthia roretzi Extracts Exhibit Anti-Photoaging Activities during Exposure to UV Irradiation, and Antibacterial Properties

Asterias pectinifera, a species of starfish and cause of concern in the aquaculture industry, was recently identified as a source of non-toxic and highly water-soluble collagen peptides. In this study, we investigated the antioxidant and anti-photoaging functions of compounds formulated using collagen peptides from extracts of Asterias pectinifera and Halocynthia roretzi (AH). Our results showed that AH compounds have various skin protective functions, including antioxidant effects, determined by measuring the scavenging activity of 2,2-diphenyl-1-picrylhydrazyl radicals, as well as anti-melanogenic effects, determined by measuring tyrosinase inhibition activity. To determine whether ethosome-encapsulated AH compounds (E(AH)) exert ultraviolet (UV)-protective effects, human dermal fibroblasts or keratinocytes were incubated with E(AH) before and after exposure to UVA or UVB. E(AH) treatment led to inhibition of photoaging-induced secretion of matrix metalloproteinase-1 and interleukin-6 and -8, which are associated with inflammatory responses during UV irradiation. Finally, the antibacterial effects of AH and E(AH) were confirmed against both gram-negative and gram-positive bacteria. Our results indicate that E(AH) has the potential for use in the development of cosmetics with a range of skin protective functions.

Post-Translational Modifications Evoked by Reactive Carbonyl Species in Ultraviolet-A-Exposed Skin: Implication in Fibroblast Senescence and Skin Photoaging

Photoaging is an accelerated form of aging resulting from skin exposure to ultraviolet (UV) radiation. UV-A radiation deeply penetrates the dermis and triggers the generation of reactive oxygen species (ROS) which promotes damage to DNA, lipids and proteins. Lipid peroxidation results from the oxidative attack of polyunsaturated fatty acids which generate a huge amount of lipid peroxidation products, among them reactive carbonyl species (RCS) such as α, β-unsaturated hydroxyalkenals (e.g., 4-hydroxynonenal), acrolein or malondialdehyde. These highly reactive agents form adducts on free NH2 groups and thiol residues on amino acids in proteins and can also modify DNA and phospholipids. The accumulation of RCS-adducts leads to carbonyl stress characterized by progressive cellular and tissular dysfunction, inflammation and toxicity. RCS-adducts are formed in the dermis of skin exposed to UV-A radiation. Several RCS targets have been identified in the dermis, such as collagen and elastin in the extracellular matrix, whose modification could contribute to actinic elastosis lesions. RCS-adducts may play a role in fibroblast senescence via the modification of histones, and the sirtuin SIRT1, leading to an accumulation of acetylated proteins. The cytoskeleton protein vimentin is modified by RCS, which could impair fibroblast motility. A better identification of protein modification and carbonyl stress in the dermis may help to develop new treatment approaches for preventing photoaging.

The Role of Probiotics in Skin Photoaging and Related Mechanisms: A Review

Solar ultraviolet radiation (UVR) is the primary pathogenetic factor in skin photoaging. It can disrupt cellular homeostasis by damaging DNA, inducing an inflammatory cascade, immunosuppression, and extracellular matrix (ECM) remodeling, resulting in a variety of dermatologic conditions. The skin microbiome plays an important role in the homeostasis and maintenance of healthy skin. Emerging evidence has indicated that highly diverse gut microbiome may also have an impact on the skin health, referred to as the gut-skin axis (GSA). Oral and topical probiotics through modulating the skin microbiome and gut-skin microbial interactions could serve as potential management to prevent and treat the skin photoaging by multiple pathways including reducing oxidative stress, inhibiting ECM remodeling, inhibiting the inflammatory cascade reaction, and maintaining immune homeostasis. In this review, the effects of oral and topical probiotics in skin photoaging and related mechanisms are both described systematically and comprehensively.

Fat infiltration into dermal layer induces aged facial appearance by decreasing dermal elasticity

BACKGROUND

Facial morphology changes with aging, producing an aged appearance, but the mechanisms involved are not fully established. We recently showed that subcutaneous fat infiltrates into the dermal layer with aging, but it is not yet clear whether and how this drastic change of the dermal layer influences facial appearance.

PURPOSE

We aimed to establish the role of fat infiltration in producing an aged facial appearance and to clarify the mechanism involved.

METHODS

We analyzed the severity of fat infiltration in cheek skin of 30 middle-aged female volunteers by means of ultrasonography. Severity of the nasolabial fold, an established age-related morphology, was evaluated based on our photographic grading criteria as a measure of aged appearance. Skin elasticity was measured with a Cutometer.

RESULTS

Fat infiltration to the dermal layer was detected at the cheek skin noninvasively by means of ultrasonography. Fat infiltration severity, measured as the minimum depth of the fat inside the dermal layer from the skin surface, was positively correlated with the magnitude of the nasolabial fold. Further, fat infiltration severity was significantly negatively correlated with dermal elasticity.

CONCLUSIONS

Our results suggest that fat infiltration into the dermal layer is a critical factor inducing aged appearance of the face. The infiltrated fat decreases the dermal elasticity, which exacerbates nasolabial folds, namely producing an aged facial appearance.

Autophagy plays an essential role in ultraviolet radiation-driven skin photoaging

Photoaging is characterized by a chronic inflammatory response to UV light. One of the most prominent features of cutaneous photoaging is wrinkling, which is due primarily to a loss of collagen fibers and deposits of abnormal degenerative elastotic material within the dermis (actinic elastosis). These changes are thought to be mediated by inflammation, with subsequent upregulation of extracellular matrix-degrading proteases and down-regulation of collagen synthesis. Autophagy is a vital homeostatic cellular process of either clearing surplus or damaged cell components notably lipids and proteins or recycling the content of the cells’ cytoplasm to promote cell survival and adaptive responses during starvation and other oxidative and/or genotoxic stress conditions. Autophagy may also become a means of supplying nutrients to maintain a high cellular proliferation rate when needed. It has been suggested that loss of autophagy leads to both photodamage and the initiation of photoaging in UV exposed skin. Moreover, UV radiation of sunlight is capable of regulating a number of autophagy-linked genes. This review will focus on the protective effect of autophagy in the skin cells damaged by UV radiation. We hope to draw attention to the significance of autophagy regulation in the prevention and treatment of skin photoaging.

Photolyase Production and Current Applications: A Review

The photolyase family consists of flavoproteins with enzyme activity able to repair ultraviolet light radiation damage by photoreactivation. DNA damage by the formation of a cyclobutane pyrimidine dimer (CPD) and a pyrimidine-pyrimidone (6-4) photoproduct can lead to multiple affections such as cellular apoptosis and mutagenesis that can evolve into skin cancer. The development of integrated applications to prevent the negative effects of prolonged sunlight exposure, usually during outdoor activities, is imperative. This study presents the functions, characteristics, and types of photolyases, their therapeutic and cosmetic applications, and additionally explores some photolyase-producing microorganisms and drug delivery systems.

Molecular mechanisms of Marine-Derived Natural Compounds as photoprotective strategies

Excessive exposure of the skin to ultraviolet radiation (UVR) causes oxidative stress, inflammation, immunosuppression, apoptosis, and changes in the extracellular matrix, which lead to the development of photoaging and photodamage of skin. At the molecular level, these pathological changes are mainly caused by the activation of related protein kinases and downstream transcription pathways, the increase of matrix metalloproteinase, the formation of reactive oxygen species, and the combined action of cytokines and inflammatory mediators. At present, the photostability, toxicity, and damage to marine ecosystems of most sun protection products in the market have affected their efficacy and safety. Another way is to use natural products produced by various marine species. Marine organisms have evolved a variety of molecular strategies to protect themselves from the harmful effects of ultraviolet radiation, and their unique chemicals have attracted more and more attention in the research of photoprotection and photoaging resistance. This article provides an extensive description of the recent literature on the potential of Marine-Derived Natural Compounds (MDNCs) as photoprotective and photoprotective agents. It reviews the positive effects of MDNCs in counteracting UV-induced oxidative stress, inflammation, DNA damage, apoptosis, immunosuppression, and extracellular matrix degradation. Some MDNCs have the potential to develop feasible solutions for related phenomena, such as photoaging and photodamage caused by UVR.

Activation of the JNKs/ATM-p53 axis is indispensable for the cytoprotection of dermal fibroblasts exposed to UVB radiation

Although UVB radiation is mainly absorbed by the epidermis, ~5-10% of its photons reach and affect the upper part of the dermis. Physiologically relevant UVB doses, able to provoke erythema, induce apoptosis in human dermal fibroblasts in vitro, as well as in the dermis of SKH-1 mice. Given the sparse and even contradictory existing information on the effect of UVB radiation on dermal fibroblasts' viability, aim of this work was to unravel the crucial signaling pathways regulating the survival of UVB-treated human dermal fibroblasts. We found that UVB radiation immediately stimulates the phosphorylation of MAPK family members, as well as Akt, and is genotoxic leading to the delayed ATM-p53 axis activation. Akt phosphorylation after UVB radiation is EGFR-mediated and EGFR inhibition leads to a further decrease of viability, while the Akt activator SC79 rescues fibroblasts to an extent by a mechanism involving Nrf2 activation. The known Nrf2 activator sulforaphane also exerts a partial protective effect, although by acting in a distinct mechanism from SC79. On the other hand, inhibition of JNKs or of the ATM-p53 axis leads to a complete loss of viability after UVB irradiation. Interestingly, JNKs activation is necessary for p53 phosphorylation, while the ATM-p53 pathway is required for the long-term activation of JNKs and Akt, reassuring the protection from UVB. Although UVB radiation results in intense and prolonged increase of intracellular ROS levels, classical anti-oxidants, such as Trolox, are unable to affect Akt, JNKs, or p53 phosphorylation and to reverse the loss of fibroblasts' viability. Collectively, here we provide evidence that the main viability-regulating UVB-triggered biochemical pathways act synergistically towards the protection of human dermal fibroblasts, with EGFR/Akt and Nrf2 serving as auxiliary anti-apoptotic machineries, while JNKs/ATM-p53 activation and interplay being overriding and indispensable for the perpetuation of cellular defense and the maintenance of cell viability.

DHPW1 attenuation of UVB-induced skin photodamage in human immortalized keratinocytes

Ultraviolet radiation (UVB) can result in photodamage to the skin and can seriously threaten health, particularly in the elderly. Oxidative stress and the inflammatory response have been shown to play a significant role in the process. In a previous study, we isolated, purified and identified a polysaccharide from the extract of Dendrobium huoshanense (DHPW1). In this study we evaluated the effect of DHPW1 on ameliorating the UVB photodamage of human immortalized keratinocytes (HaCaT). Cell proliferation and cell scratch assays were used to evaluate the viability of the HaCaT treated with DHPW1, and a fluorescent probe and Western blot analysis were used to examine the production of reactive oxygen species (ROS) and the expression of proinflammatory factors IL-1β, IL-6, and NF-κB(p65). The results show that, compared with the control group (UVB irradiation only), DHPW1 significantly improved the viability of UVB-irradiated HaCaT and enhanced the migration rate of the cell scratch after 24 h. The scratch-healing rate reached 90 % after 36 h. DHPW1 also significantly inhibited UVB-induced oxidative stress and expression of proinflammatory factors . Compared with the control group, the production of ROS decreased by 49.11 %, and the relative protein expression of IL-6 and NF-κB(p65) decreased by up to 13.30 % and 31.02 %, respectively. It is concluded that DHPW1 can significantly improve viability and wound closure rate of UVB-irradiated HaCaT. In addition, it can reduce the expression of IL-1 and IL-6 by inhibiting the transcription of NF-κB(p65), thereby reducing inflammation and oxidative stress in UVB-irradiated HaCaT.

Photoaging: UV radiation-induced inflammation and immunosuppression accelerate the aging process in the skin

Background

Excessive exposure of the skin to UV radiation (UVR) triggers a remodeling of the immune system and leads to the photoaging state which is reminiscent of chronological aging. Over 30 years ago, it was observed that UVR induced an immunosuppressive state which inhibited skin contact hypersensitivity.

Methods

Original and review articles encompassing inflammation and immunosuppression in the photoaging and chronological aging processes were examined from major databases including PubMed, Scopus, and Google Scholar.

Results

Currently it is known that UVR treatment can trigger a cellular senescence and inflammatory state in the skin. Chronic low-grade inflammation stimulates a counteracting immunosuppression involving an expansion of immunosuppressive cells, e.g., regulatory T cells (Treg), myeloid-derived suppressor cells (MDSC), and regulatory dendritic cells (DCreg). This increased immunosuppressive activity not only suppresses the function of effector immune cells, a state called immunosenescence, but it also induces bystander degeneration of neighboring cells. Interestingly, the chronological aging process also involves an accumulation of pro-inflammatory senescent cells and signs of chronic low-grade inflammation, called inflammaging. There is also clear evidence that inflammaging is associated with an increase in anti-inflammatory and immunosuppressive activities which promote immunosenescence.

Conclusion

It seems that photoaging and normal aging evoke similar processes driven by the remodeling of the immune system. However, it is likely that there are different molecular mechanisms inducing inflammation and immunosuppression in the accelerated photoaging and the chronological aging processes.

Focus on the Contribution of Oxidative Stress in Skin Aging

Skin aging is one of the most evident signs of human aging. Modification of the skin during the life span is characterized by fine lines and wrinkling, loss of elasticity and volume, laxity, rough-textured appearance, and pallor. In contrast, photoaged skin is associated with uneven pigmentation (age spot) and is markedly wrinkled. At the cellular and molecular level, it consists of multiple interconnected processes based on biochemical reactions, genetic programs, and occurrence of external stimulation. The principal cellular perturbation in the skin driving senescence is the alteration of oxidative balance. In chronological aging, reactive oxygen species (ROS) are produced mainly through cellular oxidative metabolism during adenosine triphosphate (ATP) generation from glucose and mitochondrial dysfunction, whereas in extrinsic aging, loss of redox equilibrium is caused by environmental factors, such as ultraviolet radiation, pollution, cigarette smoking, and inadequate nutrition. During the aging process, oxidative stress is attributed to both augmented ROS production and reduced levels of enzymatic and non-enzymatic protectors. Apart from the evident appearance of structural change, throughout aging, the skin gradually loses its natural functional characteristics and regenerative potential. With aging, the skin immune system also undergoes functional senescence manifested as a reduced ability to counteract infections and augmented frequency of autoimmune and neoplastic diseases. This review proposes an update on the role of oxidative stress in the appearance of the clinical manifestation of skin aging, as well as of the molecular mechanisms that underline this natural phenomenon sometimes accelerated by external factors.

Genome-Wide RNA Sequencing Analysis in Human Dermal Fibroblasts Exposed to Low-Dose Ultraviolet A Radiation

Ultraviolet A (UVA) radiation can pass through the epidermis and reach the dermal skin layer, contributing to photoaging, DNA damage, and photocarcinogenesis in dermal fibroblasts. High-dose UVA exposure induces erythema, whereas low-dose, long-term UVA exposure causes skin damage and cell senescence. Biomarkers for evaluating damage caused by low-dose UVA in fibroblasts are lacking, making it difficult to develop therapeutic agents for skin aging and aging-associated diseases. We performed RNA-sequencing to investigate gene and pathway alterations in low-dose UVA-irradiated human skin-derived NB1RGB primary fibroblasts. Differentially expressed genes were identified and subjected to Gene Ontology and reactome pathway analysis, which revealed enrichment in genes in the senescence-associated secretory phenotype, apoptosis, respiratory electron transport, and transcriptional regulation by tumor suppressor p53 pathways. Insulin-like growth factor binding protein 7 (IGFBP7) showed the lowest p-value in RNA-sequencing analysis and was associated with the senescence-associated secretory phenotype. Protein–protein interaction analysis revealed that Fos proto-oncogene had a high-confidence network with IGFBP7 as transcription factor of the IGFBP7 gene among SASP hit genes, which were validated using RT-qPCR. Because of their high sensitivity to low-dose UVA radiation, Fos and IGFBP7 show potential as biomarkers for evaluating the effect of low-dose UVA radiation on dermal fibroblasts.

Age-Defying and Photoprotective Potential of Geranium/Calendula Essential Oil Encapsulated Vesicular Cream on Biochemical Parameters against UVB Radiation Induced Skin Aging in Rat

UVB irradiation promotes the production of reactive oxygen species, which can lead to an increase in oxidative stress in the cell and the generation of toxic components, resulting in photoaging. Essential oils (EOs) are well-known in the cosmetics sector for their beneficial effects, as they have a wide range of biological activities. Considering this fact, the current study investigates the photoprotective potential of geranium essential oil (GEO)/calendula essential oil (CEO) encapsulated vesicular cream on the biochemical parameters of the skin of albino rats exposed to UVB radiation. After 30 days of treatment with cream formulations and UVB irradiation, the skin tissue was assayed for several biochemical parameters and histopathology analysis. The results of biochemical study revealed that, in comparison to non-vesicular creams, vesicular cream formulations were able to protect the endogenous skin natural antioxidant system by maintaining superoxide dismutase, catalase, total protein, ascorbic acid, and hydroxyproline levels and by decreasing malondialdehyde levels in the skin after UVB exposure. Changes in various cellular structures along with the change in the epidermis and dermis of the skin after UVB exposure in the treated group were observed by a histopathology of skin tissue and compared to the non-treated group, which revealed the skin damaging effect of UVB radiation and the protective effect of vesicular creams. The results suggest that the GEO/CEO-encapsulated vesicular creams have the potential to protect the skin against harmful UVB radiation by maintaining the natural antioxidant defence mechanism of the skin. In conclusion, this research presents novel herbal cosmetic formulations with improved antioxidant capacity and photoprotective potential that may help to slow down the skin aging process.

Long-acting microneedle patch loaded with adipose collagen fragment for preventing the skin photoaging in mice

Skin photoaging is one of the most serious public health problems in the 21st century that may lead to thin, saggy, and structurally weakened skin. Adipokine therapy toward skin photoaging is always associated with poor permeability, biologic stability and the short in vivo release duration. Our laboratory previously extracted an extracellular matrix component of adipose tissue by purely physical methods, namely "adipose collagen fragment (ACF)", which holds promise for preventing skin photoaging. However, the injection treatment of ACF requires repeated preparation processes and injection procedures, which may be time-consuming and painful. Therefore, we describe the fabrication and assessment of a detachable ACF-microneedle (ACF-MN) patch that creates minimally invasive dermal microtrauma upon application. And we evaluated the morphology characterization, mechanical properties and puncture performance in vitro. The delivery efficiency of ACF from the patches was estimated in vitro and vivo. Then, the therapeutic efficacy was identified through applying ACF-MN patches into the dermis of UVA-induced photoaging mice and the related detection of skin photoaging was estimated. Our results demonstrated that ACF-MN exhibited well skin puncture performance and could release ACF component slowly. Meanwhile, this microneedle device loaded with ACF exhibited the treatment efficiency on skin photoaging in a mouse model. Therefore, implantation of the microtrauma-mediated, long-acting ACF-MN system can be utilized as a potential candidate for preventing skin photoaging in the clinic.

Secretomes as an emerging class of bioactive ingredients for enhanced cosmeceutical applications

Skin aging is predominantly caused by either intrinsic or extrinsic factors, leading to undesirable skin features. Advancements in both molecular and cellular fields have created possibilities in developing novel stem cell-derived active ingredients for cosmeceutical applications and the beauty industry. Mesenchymal stromal cell (MSC)-derived secretomes or conditioned media hold great promise for advancing skin repair and regeneration due to the presence of varying cytokines. These cytokines signal our cells and trigger biological mechanisms associated with anti-inflammatory, antioxidant, anti-aging, proliferative, and immunomodulatory effects. In this review, we discuss the potential of MSC secretomes as novel biomaterials for skincare and rejuvenation by illustrating their mechanism of action related to wound healing, anti-aging, and whitening properties. The advantages and disadvantages of secretomes are compared to both plant-based and animal-derived extracts. In addition, this paper reviews the current safety standards, regulations, market products and research work related to the cosmeceutical applications of secretomes along with strategies to maintain and improve the therapeutic efficacy and production of secretomes. The future outlook of beauty industry is also presented. Lastly, we highlight significant challenges to be addressed for the clinical realization of MSC secretomes-based skin therapies as well as providing perspectives for the future direction of secretomes.

Inhibitory Effect of Lotusine on Solar UV-Induced Matrix Metalloproteinase-1 Expression

Solar ultraviolet (sUV) radiation remains a major cause of skin aging. Nelumbo nucifera (lotus) is a well-known edible plant widely grown in Asia, including Korea, China, and Japan. The lotus consists of flowers, leaves, stems, and seeds, and all parts reportedly possess nutritional and medical values. Traditionally, lotus flowers, leaves, stems, and seeds have been used as antidiarrheal agents, diuretics, antipyretics, and antimicrobial and antihyperlipidemic agents. In addition, the Nelumbo nucifera lotus embryo has been shown to possess sedative and antipyretic properties and can relieve hemostatic thirst and treat eye diseases. Recently, Nelumbo nucifera lotus flower extract has been widely used in cosmetics due to its ability to reduce wrinkles and its whitening effects. Numerous cosmetics using Nelumbo nucifera lotus embryo extracts are commercially available. However, the active components of Nelumbo nucifera remain elusive. Lotusine is a phytochemical and soluble alkaloid found in lotus embryos. Herein, we examined the anti-wrinkle effect of lotusine using sUV-exposed human keratinocytes. We observed that lotusine reduced sUV-induced matrix metalloproteinase (MMP)-1 expression and modulated transcriptional activities of activator protein (AP)-1 and nuclear factor kappa B (NF-κB). sUV-induced AP-1 and NF-κB activity could be activated via multiple signal transduction cascades, including the p38 MAPK, JNK, ERK1/2, and Akt pathways in the skin. Lotusine inhibited the MEK1/2-ERK1/2-p90^RSK, MKK3/6-p38, and Akt-p70^S6K pathways. Overall, our findings suggest that lotusine has potential benefits related to MMP-1 expression and skin aging following sUV exposure. Hence, the lotus can be developed as a valuable functional food and cosmetic material.

Photoprotection for Skin of Color

Photoprotection behaviors can mitigate skin damage caused by ultraviolet radiation, and common methods include seeking shade, avoiding sun exposure during peak daylight hours, wearing sun-protective clothing, applying sunscreen, and using sunglasses. While the role of sun protection in preventing sunburns, photoaging, and skin cancer is well established in fair-skinned populations, individuals with skin of color (SOC) are presumed to suffer fewer negative effects from solar radiation. Thus, the importance of photoprotection in this population is understudied and may be underestimated. In SOC populations, sun exposure is known to cause pigmentary disorders, photoaging, and basal cell carcinoma (BCC), highlighting the potential benefits of photoprotection. Although SOC populations tend to practice photoprotection by seeking shade and wearing sun-protective clothing, survey and interview-based studies have consistently found relatively low use of sunscreen among these populations. Common motivators for photoprotection in individuals with SOC include preventing sunburn and pigmentation, with the prevention of skin cancer being a less important reason. As a skin cancer risk behavior, indoor tanning is relatively rare in SOC populations, but its use may increase with acculturation to US norms. While more studies are necessary to clarify whether photoprotection behaviors may decrease skin cancer-related mortality in SOC populations, regular dermatologic care and counseling on photoprotection remain essential in patients with SOC for overall skin health.

"Split-Face" Evaluation of Collagen Changes Induced by Periorbital Fractional CO2 Laser Resurfacing

BACKGROUND

Periorbital fractional CO2 laser resurfacing has been employed for facial rejuvenation purposes. However, to the best of our knowledge, no study has objectively assessed periorbital neoformation and remodeling of local cutaneous collagen, in a split-face model, from skin samples obtained during upper blepharoplasty.

OBJECTIVES

The authors sought to objectively evaluate neoformation and remodeling of local cutaneous collagen after periorbital skin fractional CO2 laser resurfacing.

METHODS

Sixteen female patients presenting with dermatochalasis and periorbital rhytids were evaluated in a prospective and comparative study. All patients underwent unilateral periorbital fractional CO2 laser resurfacing 30 days before upper blepharoplasty. Quantification of types I and III collagen from laser-treated and untreated eyelid skin samples obtained during upper blepharoplasty was assessed with histochemical analysis (Picrosirius Red staining). Laser resurfacing treatment was applied to the untreated side immediately after the upper blepharoplasty. Two blinded, independent physicians evaluated clinical improvement in pretreatment and 1- and 6-month posttreatment digital images.

RESULTS

Histochemical analysis showed significantly higher intensity in collagen types I (treated: 158.7 ± 5.3, untreated: 139.2 ± 5.0; P < 0.0001) and III (treated: 105.1 ± 7.7, untreated: 104.1 ± 7.1; P < 0.0001) in the fractional CO2 laser treatment samples; a greater difference was detected in collagen type I. A significant improvement in periorbital rhytidosis was observed 1 month after laser resurfacing (23%); a greater improvement in the periorbital region was observed 6 months after laser resurfacing and upper blepharoplasty (43.67%).

CONCLUSIONS

Periorbital fractional CO2 laser resurfacing was an effective method to improve palpebral skin, with histochemical evidence of increase in collagen types I and III.

LEVEL OF EVIDENCE: 4

Systematic review and meta-analysis of randomized clinical trials comparing efficacy, safety, and satisfaction between ablative and non-ablative lasers in facial and hand rejuvenation/resurfacing

Skin aging inevitably begins from the very early days of life. The lasers used in skin rejuvenation are mainly of two types: ablative and non-ablative. This meta-analysis aimed at comparing ablative with non-ablative lasers in terms of their efficacy and safety in skin rejuvenation. Articles published by March 15, 2020 in Embase, Medline (PubMed), Scopus, Cochrane, and clinicalTrials.gov were searched. The inclusion criteria included randomized controlled clinical trials (RCTs) in English using ablative and non-ablative lasers and comparing their safety and efficiency in wrinkle improvement and photoaging therapy. Out of 1353 extracted articles, 11 were selected for qualitative synthesis and of these, 4 were quantitatively analyzed. Different modes of various lasers were implemented; the ablative lasers included Erbium: yttrium-aluminium-garnet (Er:YAG) and CO₂, besides the non-ablative lasers, comprised Ytterbium/Erbium, Erbium: Glass, neodymium: yttrium-aluminum-garnet (Nd:YAG), and alexandrite. Pooled analyses on 124 participants showed insignificant differences between ablative and non-ablative lasers in the likelihood of excellent improvement with an odds ratio of 0.83 (95% CI: 0.24, 2.83). The analyses also showed good improvement with an odds ratio of 0.88 (95% CI: 0.44, 1.78), fair improvement with an odds ratio of 1.13 (95% CI: 0.56, 2.26) and side effects with an odds ratio of 0.82 (95% CI: 0.43, 1.56). The efficacy and safety of ablative laser were not higher than those of non-ablative laser in skin rejuvenation. Given the small samples of the included articles, it is recommended that further high-quality RCTs be conducted using larger samples to confirm this conclusion.

A sunscreen nanoparticles polymer based on prolonged period of protection

UV rays are one of the most dangerous factors that harm the skin. There is continuous improvement in getting an effective sunscreen that protects the skin from excessive exposure to UV rays. Typically, phenylbenzimidazole-5-sulfonic acid (PBSA) is used as a sun blocking agent, but its disadvantage is that it can photodegrade and cause cell damage. In our work, PBSA was encapsulated in niosomes nanoparticles then coated with chitosan-aloe vera (CS-nio-aloe/PBSA) to form a carrier polymer with novel and potent properties. This polymer controls PBSA release and epidermal penetration. Characterization of CS-nio-aloe/PBSA polymer nanoparticles through transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and dynamic light scattering (DLS). The carrier polymer release rate was studied in vitro and epidermal permeability to coated PBSA was assessed using mouse skin. The nanoparticle polymer containing sunscreen was effectively prepared with an encapsulation efficiency of 80%. The formulation (CS-nio-aloe/PBSA) was completely deposited on the surface of the skin. This supports its use to protect the skin, and its nanostructures stimulate the release of PBSA for a longer period. Encapsulation of PBSA in CS-nio-aloe nanoparticles could allow for further cellular preservation, UV protection, control of free PBSA, and limited penetration through the mouse skin epidermis.

Photo-aging evaluation - In vitro biological endpoints combined with collagen density assessment with multi-photon microscopy

BACKGROUND

Ultraviolet exposure has profound effect on the dermal connective tissue of human skin.

OBJECTIVE

We aimed to develop and validate an evaluation method/methodology using a full-thickness reconstructed skin model, to assess the anti-photoaging efficacy of cosmetic ingredients and sunscreen formulas by blending multi relevant biological endpoints including the newly developed dermal collagen quantification method with Multi-photon microscopy.

METHODS

The response of ex vivo human skin to UVA exposure was first characterized with multiphoton microscopy. Reconstructed full-thickness skin models was then used to reproduce the data and to create a proof-of-concept study by treating the models with sunscreen prototypes A or B, which differ on their UVA absorption properties, and systemic Vitamin C (Vit C). After exposure to UVA, the collagen density was quantified via multiphoton microscopy with automatic imaging processing. Histology, fibroblasts number, metalloprotease 1 (MMP1) secretion were also assessed.

RESULTS

UVA exposure induced pronounced reduction in collagen density and increased MMP1 secretion within both ex vivo human skin and reconstructed skin. Histological damage and fibroblast disappearance was observed with reconstructed skin. Within the proof-of-concept study prototype B, possessing higher UVA filtration, gave better protection than prototype A on the UV associated biological markers, and association with Vit C boosted sunscreen formula efficacy.

CONCLUSIONS

The photoaging evaluation method, consists of multi biological markers as well as dermal collagen quantification, is a relevant mean to assess the pre-clinical efficacy of anti-photoaging ingredients and sunscreen products. This approach is also beneficial for evaluating the efficacy of sunscreens and photoprotective ingredients.

Nicotinamide Prevents UVB- and Oxidative Stress-Induced Photoaging in Human Primary Keratinocytes

Nicotinamide (NAM), a NAD⁺ precursor, is known for its benefits to skin health. Under standard culture conditions, NAM delays the differentiation and enhances the proliferation of human primary keratinocytes (HPKs), leading to the maintenance of stem cells. Here, we investigated the effects of NAM on photoaging in 2D HPK cultures and 3D organotypic epidermal models. In both models, we found that UVB irradiation and hydrogen peroxide induced HPK premature terminal differentiation and senescence. In 3D organotypics, the phenotype was characterized by a thickening of the granular layer expressing filaggrin and loricrin, but thinning of the epidermis overall. NAM limited premature differentiation and ameliorated senescence, as evidenced by the maintenance of lamin B1 levels in both models, with decreased lipofuscin staining and reduced IL-6/IL-8 secretion in 3D models, compared to UVB-only controls. In addition, DNA damage observed after irradiation was accompanied by a decline in energy metabolism, while both effects were partially prevented by NAM. Our data thus highlight the protective effects of NAM against photoaging and oxidative stress in the human epidermis, and pinpoint DNA repair and energy metabolism as crucial underlying mechanisms.

The role of local retinoids in eliminating signs of skin aging

Skin aging is a complex process involving both internal (chronological aging) and external (biological aging) factors. Slowing down the proliferative and immune processes in the epidermis, reducing the activity of fibroblasts and vascularization of the dermis during chronological aging lead to thinning, dryness, hypersensitivity, vulnerability and superficial wrinkles. Exposure to ultraviolet rays, pollutants, climate, and thermal factors cause keratinocyte disorganization, enhanced melanogenesis, collagen dystrophy, solar elastosis, and disorder of microcirculation. The main signs of external skin aging are deep wrinkles, sagging, pigmentation, telangiectasia, skin neoplasms. Among the local anti-aging agents, retinoids occupy a leading place, as they eliminate the main signs of skin aging. Of the entire group of retinoids, retinoic acids are the most active. However, the possibility of skin irritation limits their use. Therapeutic and cosmetic products with retinol esters (retinol palmitate) have a minimal irritating effect and can be used both for the prevention of skin aging and the elimination of its signs. Oral use of isotretinoin as an anti-aging agent is undesirable due to the many side effects and contraindications.

An Adipose-Derived Injectable Sustained-Release Collagen Scaffold of Adipokines Prepared Through a Fast Mechanical Processing Technique for Preventing Skin Photoaging in Mice

Ultraviolet A (UVA) radiation is the major contributor to skin photoaging, associated with increased collagen degradation and reactive oxygen species (ROS) expression. Adipokines have been proven as promising therapeutic agents for skin photoaging. However, adipokine therapy is generally limited by the short in vivo release duration and biological instability. Therefore, developing a treatment that provides a sustained release of adipokines and enhanced therapeutic effects is desirable. In this study, we developed a novel mechanical processing technique to extract adipose tissue-derived ECM components, named the "adipose collagen fragment" (ACF). The physical characterization, injectability, collagen components, residual DNA/RNA and adipokine release pattern of ACF were identified in vitro. L929 cells were treated with ACF or phosphate-buffered saline for 24 h after UVA irradiation in vitro. The expression of senescence-associated xβ-galactosidase (SA-β-gal), ROS and antioxidase were investigated. Then, we evaluated its therapeutic efficacy by injecting ACF and phosphate-buffered saline, as a control, into the dermis of photoaging nude mice and harvesting skin samples at weeks 1, 2, and 4 after treatment for assessment. The content of adipokines released from ACF was identified in vivo. The collagen synthesis and collagen degradation in ACF implants were evaluated by immune staining. Dermal thickness, fibroblast expression, collagen synthesis, ROS level, antioxidase expression, capillary density, and apoptotic cell number were evaluated by histological assessment, immune staining, and polymerase chain reaction in the skin samples. We demonstrated that ACF is the concentrated adipose extracellular matrix collagen fragment without viable cells and can be injected through fine needles. The lower expression of SA-β-gal, ROS and higher expression of antioxidase were observed in the ACF-treated group. ACF undergoes collagen degradation and promotes neocollagen synthesis in ACF implants. Meanwhile, ACF serves as a sustained-release system of adipokines and exhibits a significantly higher therapeutic effect on mouse skin photoaging by enhancing angiogenesis, antioxidant abilities, antiapoptotic activities, and collagen synthesis through sustainedly releasing adipokines. To sum up, ACF is an adipokines-enriched, sustained-release extracellular matrix collagen scaffold that can prevent UVA-induced skin photoaging in mice. ACF may serve as a novel autologous skin filler for skin rejuvenation applications in the clinic.

Protective effects of GLHP from Gracilaria lemaneiformis against UVB-induced photodamage in human immortalized keratinocytes cells and BALB/c mice

Our previous study showed that the water-soluble heteropolysaccharide extracted from Gracilaria lemaneiformis (GLHP) has excellent anti-inflammation and anti-oxidant properties. This study explored the efficacy of GLHP against skin anti-photoaging in human immortalized keratinocytes (HaCaT) cells and BALB/c mice under UVB irradiation. Cell viability, antiapoptotic, reactive oxygen species (ROS) scavenging activity, mitochondrial membrane potential, and cell wound scratch assays were conducted, as well as assessment of inflammation markers and sun protection factors. The in vitro results showed that GLHP pretreatment significantly inhibited UVB-induced apoptosis, reversed the decrease of cell viability via downregulating the expression of apoptosis-related protein caspase-3, accelerated the migration of HaCaT cells, and promoted wound healing. Notably, the protective effect of GLHP may be associated with the scavenging of ROS and the decrease of mitochondrial membrane potential. Moreover, GLHP pretreatment significantly restrained the upregulation of iNOS (UVB-induced inflammation marker), suppressed the expression of P-ERK and NF-κB, and decreased the activity of MMPs, suggesting that it exerts the therapeutic effects by inhibiting the MAPK/NF-κB signal pathway. Results obtained after conducting the in vivo assay confirmed that GLHP could reverse the UVB-induced increase of epidermal thickness in BALB/c mice. In conclusion, this study shows that GLHP can be utilized as a safer resource in the manufacture of anti-aging cosmetics because it exerts excellent anti-photoaging effects.