Photoaging

Photoprotective effects of quercetin on photoaging-induced rats

PURPOSE

Photoaging is characterised by cutaneous changes caused by exposure to ultraviolet light over time. Quercetin is a bioflavanoid with antioxidant, antineoplastic, and anti-inflammatory effects. This study investigated the therapeutic effects of topical quercetin on photoaging, a phenomenon not previously studied in ultraviolet A (UVA)-induced photoaging.

METHODS

A total of 40 rats were randomly categorised into 5 groups, each comprising 8 rats. A photoaging model was induced by applying UVA to the dorsal region of all rats, except for the negative control group. Topical 0.1% retinoic acid was applied to one UVA group, topical 0.3% quercetin to another UVA group, and both agents were applied in combination to yet another UVA group 5 days a week for 8 weeks. Subsequently, wrinkle values were measured, reactive oxygen species (ROS) and matrix metalloproteinase-1 (MMP-1) levels were analysed, and histopathological parameters were examined.

RESULTS

The wrinkle value of the UVA group was found to be significantly higher than that of the UVA + Quercetin group. Collagen damage was lower in the UVA + Quercetin group than in the UVA group, although this difference was not statistically significant. Compared with the UVA + Retinoic Acid group, the UVA + Quercetin group exhibited a more significant decrease in inflammation. MMP-1 values were considerably higher in the UVA + Retinoic Acid and UVA + Quercetin + Retinoic Acid groups as well as in the UVA + Quercetin group compared with the control and UVA groups.

CONCLUSION

The present study showed that quercetin can be utilised in the treatment of photoaging, especially when combined with retinoic acid.

Prebiotic and panthenol-containing dermocosmetic improves tolerance from artificial daylight photodynamic therapy: A randomized controlled trial in patients with actinic keratosis

INTRODUCTION & OBJECTIVES

Treatment with daylight photodynamic therapy (dPDT) of actinic keratosis (AK) is associated with local skin reactions (LSR), which may affect patients' quality of life and treatment acceptability. This study explores the potential of a prebiotic and panthenol-containing Dermocosmetic Cream (DC) to enhance tolerance and mitigate post-dPDT induced LSR in the treatment of AKs.

MATERIALS & METHODS

This randomized controlled, intra-individual trial included 20 patients with ≥10 AKs in two symmetrical areas on their face or décolleté, treated with a single session of artificial dPDT. After treatment, the two areas were randomized to DC twice daily for 14 days or No-DC. Primary outcomes included clinical signs of LSR graded from 0=none to 3=severe, calculated as a composite score, and assessed on Days 2, 7, 14, and 30 post-treatment, along with AK clearance rate. Secondary outcomes encompassed objectively measured erythema, and clinical and objective skin photoaging assessment.

RESULTS

Topical application of DC following dPDT significantly improved post-treatment tolerance up to two weeks. By Day 2, DC-treated skin had milder LSR (median 3.0, IQR 2.0-4.8) compared to No-DC skin (median 4.0, IQR 3.0-5.0; p=0.011). This improvement continued on Day 7 (DC median 3.0, IQR 2.0-3.8 vs. No-DC median 4.5, IQR 3.0-5.8; p<0.001) and Day 14 (DC median 1.0, IQR 0.0-1.0 vs. No-DC median 1.0, IQR 1.0-2.0; p=0.004). Objective measurements showed milder erythema in DC-treated areas on Day 2 (p=0.045) and Day 7 (p=0.005). Crusting resolved more effectively in DC-treated areas by Day 7 (40% vs. 20%; p=0.039). No significant difference in complete lesion response rate was observed between DC and No-DC skin (p=0.850). By Day 30, clinical photoaging assessment demonstrated significant improvement in dyspigmentation (p=0.004) and skin texture (p<0.001) in both locations. Moreover, objective measurements revealed reduced dyspigmentation in both DC and No-DC treated skin (p≤0.001).

CONCLUSION

Application of a prebiotic and panthenol-containing multipurpose DC significantly enhanced tolerance from artificial dPDT and accelerated healing time up to 14 days after treatment. The use of DC cream did not affect the overall treatment efficacy of dPDT, indicating its potential to enhance patient comfort following dPDT.

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.

Skin microbiome profiling reveals the crucial role of microbial metabolites in anti-photoaging

BACKGROUND

Skin microbiota is essential for health maintenance. Photoaging is the primary environmental factor that affects skin homeostasis, but whether it influences the skin microbiota remains unclear.

OBJECTIVE

The objective of this study is to investigate the relationship between photoaging and skin microbiome.

METHODS

A cohort of senior bus drivers was considered as a long-term unilateral ultraviolet (UV) irradiated population. 16S rRNA amplicon sequencing was conducted to assess skin microbial composition variations on different sides of their faces. The microbiome characteristics of the photoaged population were further examined by photoaging guinea pig models, and the correlations between microbial metabolites and aging-related cytokines were analyzed by high-throughput sequencing and reverse transcription polymerase chain reaction.

RESULTS

Photoaging decreased the relative abundance of microorganisms including Georgenia and Thermobifida in human skin and downregulated the generation of skin microbe-derived antioxidative metabolites such as ectoin. In animal models, Lactobacillus and Streptobacillus abundance in both the epidermis and dermis dropped after UV irradiation, resulting in low levels of skin antioxidative molecules and leading to elevated expressions of the collagen degradation factors matrix metalloproteinase (MMP)-1 and MMP-2 and inflammatory factors such as interleukin (IL)-1β and IL-6.

CONCLUSIONS

Skin microbial characteristics have an impact in photoaging and the loss of microbe-derived antioxidative metabolites impairs skin cells and accelerates the aging process. Therefore, microbiome-based therapeutics may have potential in delaying skin aging.

Supramolecular Salicylic Acid Alleviates Skin Photoaging by Increasing Collagen Density and Elasticity

BACKGROUND

Skin rejuvenation has always been of great concern. Although salicylic acid (SA) has multiple properties, it is mainly used in dermatology as a superficial peeling agent that can improve photodamaged epidermis. However, the effect of SA on the photoaging dermis is unclear.

PURPOSE

To evaluate the efficacy and safety of supramolecular SA alone for treating photoaged skin, and the effect of SSA on photoaged dermis.

METHODS

This is a double-blind, randomized, placebo-controlled trial. 36 patients with photodamaged hands were enrolled. One hand was randomly selected as SSA treated side. 30% SSA biweekly and 2% SSA daily was applied for 4 months; an additional follow-up was performed 2 weeks after the last treatment. Skin photoaging score (SPS), global aesthetic improvement scale (GAIS), viscoelasticity, ultrasound parameters, color and transepidermal water loss (TEWL) were assessed.

RESULTS

SSA treatment induced a significant increase in collagen density and skin elasticity, accompanied by an increase in dermal thickness and a decrease in melanin index and TEWL. As result, the GAIS and the SPS were improved significantly after SSA treatment. No adverse events were observed after SSA treatments, and 98% of the subjects were satisfied or very satisfied with the treatment.

CONCLUSION

SSA can increase collagen density and skin elasticity to alleviate skin photoaging effectively and safely.

LEVEL OF EVIDENCE I

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Discovery of matrix metalloproteinase inhibitors as anti-skin photoaging agents

Photodamage is the result of prolonged exposure of the skin to sunlight. This exposure causes an overexpression of matrix metalloproteinases (MMPs), leading to the abnormal degradation of collagen in the skin tissue and resulting in skin aging and damage. This review presents a detailed overview of MMPs as a potential target for addressing skin aging. Specifically, we elucidated the precise mechanisms by which MMP inhibitors exert their anti-photoaging effects. Furthermore, we comprehensively analyzed the current research progress on MMP inhibitors that demonstrate significant inhibitory activity against MMPs and anti-skin photoaging effects. The review also provides insights into the structure-activity relationships of these inhibitors. Our objective in conducting this review is to provide valuable practical information to researchers engaged in investigations on anti-skin photoaging.

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.

Cosmetic Dermatology Concerns in Older Adults

It is important to understand that each layer of facial tissue, from the underlying facial skeleton to the overlying skin, undergoes significant changes during the aging process. Bony support is lost along the mandible and maxilla and the orbital aperture widens. Superficial and deep fat pads undergo volume loss and migration and the overlying skin begins to reveal signs of both intrinsic aging with skin laxity and fine rhytids as well as extrinsic aging in the form of coarse, deeper rhytids and dyspigmentation.

Antiaging effects of a skin care formulation containing nanoencapsulated antioxidants: A clinical, in vitro, and ex vivo study

BACKGROUND

The development of effective cosmetic products for the reduction of the signs of skin aging is a complex process which requires an optimized combination of ingredients and specialized systems to deliver the actives to the skin layers.

AIM

To evaluate the tolerance and antiaging clinical efficacy of a cosmetic formulation containing a blend of nanoencapsulated antioxidants: ascorbyl palmitate, resveratrol, tocopherol, caffeine, carnosine, and niacinamide.

METHODS

Clinical efficacy was determined by subjective and instrumental analyses of collagen synthesis by fluorescence spectroscopy, by three-dimensional imaging analysis of suborbital edema, and by analysis of skin hydration and sebum content by biophysical techniques-Corneometer® and Sebumeter®.

RESULTS

The studied formulation was safe and effective for the improvement of skin appearance by increasing collagen synthesis and skin moisturizing and by reducing facial blemishes, swelling, and oiliness. A preclinical exploratory approach using an experimental model of human cell and skin cultures agreed with the observed antiaging effects, identifying mechanisms related to the containment of oxidative stress, reduction of melanin production, increased synthesis of type I procollagen, and regulation of the epidermal cohesion protein filaggrin.

CONCLUSIONS

The skin benefits obtained resulted from the combination of the ingredients in the formulation and the nanoencapsulation-based delivery system, which favors the solubility, safety, efficacy, and bioavailability of the preparation to the skin.

Clinically Actionable Topical Strategies for Addressing the Hallmarks of Skin Aging: A Primer for Aesthetic Medicine Practitioners

In this narrative review, we sought to provide a comprehensive overview of the mechanisms underlying cutaneous senescence, framed by the twelve traditional hallmarks of aging. These include genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, impaired macroautophagy, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, altered intercellular communication, chronic inflammation, and dysbiosis. We also examined how topical interventions targeting these hallmarks can be integrated with conventional aesthetic medicine techniques to enhance skin rejuvenation. The potential of combining targeted topical therapies against the aging hallmarks with minimally invasive procedures represents a significant advancement in aesthetic medicine, offering personalized and effective strategies to combat skin aging. The reviewed evidence paves the way for future advancements and underscores the transformative potential of integrating scientifically validated interventions targeted against aging hallmarks into traditional aesthetic practices.

Comparison the Effect of Conventional and Nanofat Injection Methods on Nasolabial Fold Lipofilling: A Case- Control Study

Background

Nasolabial folds are a common sign of aging, accompanied by various manifestations such as skin and tissue loosening, wrinkles, lip corner drooping, mandibular angle loss, platysmal bands, and skin pigmentation changes. Limited research has explored Nanofat injection methods. this study was done with the aim of comparing the effect of fat injection by two methods, conventional and Nanofat, in nasolabial folds.

Method

The study conducted in 2020-2021 at the skin clinic in Ilam, western Iran was a case-control study. Participants were divided into two groups, and lipofilling procedures were performed using conventional and nanofat methods with autologous fat. Data collection utilized a researcher-made questionnaire and radiographic results. Follow-up visits occurred on the 30th, 90th, and 180th days to assess complications and recovery rates. After 6 months, participant's photographs were taken and compared with pre-intervention photographs using the GIAS criteria. Data analysis was conducted using SPSS22 version software.

Results

The average age of the participants was 37.80±8.30 yr. The treatment response in the conventional fat injection group was significantly better than the nanofat group (P<0.05). Both groups were satisfied with the treatment methods, but high satisfaction was reported in the conventional group, but there was no statistically significant difference between the groups.

Conclusion

Both methods of improving wrinkles were effective, but the improvement and response to treatment in the conventional method was better than the Nanofat method, and its effect was felt by the participants for an average period of 3 months.

The correlation between dermoscopy and clinical and pathological tests in the evaluation of skin photoaging

BACKGROUND

There are no standards for evaluating skin photoaging. Dermoscopy is a non-invasive detection method that might be useful for evaluating photoaging.

OBJECTIVE

To assess the correlation between the dermoscopic evaluation of photoaging and clinical and pathological evaluations.

METHODS

The age, clinical evaluation (Fitzpatrick classification, Glogau Photoaging Classification, and Chung's standardized image ruler), histopathology (Masson staining and MMP-1 immunohistochemistry), and dermoscopy (Hu's and Isik's) of 40 donor skin samples were analyzed statistically, and Spearman rank correlation analysis was performed.

RESULTS

There was a robust correlation between the total Hu scores and Isik dermoscopy. The correlation of dermoscopy with histopathology was higher than that of clinical evaluation methods. There is a strong correlation between telangiectases and lentigo. Xerosis, superficial wrinkle, diffuse erythema, telangiectases, and reticular pigmentation were significantly correlated with the three clinical evaluation methods. Superficial wrinkles were correlated with Masson, MMP-1, various clinical indicators, and other dermoscopic items.

CONCLUSION

There is a good correlation between dermoscopy and clinical and histopathological examination. Dermoscopy might help evaluate skin 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.

Efficacy and mechanism of retinyl palmitate against UVB-induced skin photoaging

Retinyl palmitate (RP) is a vitamin A derivative that has been widely used in anti-aging and skin treatment. The aim of this study is to investigate the effect of RP on UVB (Ultraviolet radiation B) induced photoaging and its potential mechanism. Immunofluorescence assay demonstrates that RP can reduce collagen degradation in skin cells by UVB radiation and reduce apoptosis of skin cells. Cell migration assay reveals that RP can increase cell migration rate, helping to repair skin damage and restore cell viability. Immunohistochemical assays indicate that RP can significantly reduce the expression of IL-6, IL-1β, TNF-α induced by UVB radiation. Moreover, metabolomics and transcriptomics results suggest that RP regulates several metabolic pathways and gene expression, particularly in inflammatory signaling pathways, collagen synthesis and apoptosis, exhibiting significant regulatory effects. Furthermore, network pharmacological analysis predicts that RP may affect UVB-induced photoaging by regulating multiple key proteins and signaling pathways. Overall, this study demonstrates that RP has significant anti-photoaging ability, acting through several pathways including inhibition of inflammatory response, promotion of collagen synthesis and inhibition of apoptosis. These results provide a scientific basis for the application of RP in skin anti-photoaging and therapy, enabling the potential usage of RP to skin care products.

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.

Periorbital Skin Rejuvenation of Asian Skin Using Microneedle Fractional Radiofrequency

BACKGROUND

The periorbital area plays an important role cosmetically. Periorbital wrinkles are attributed to long-term, repeated use of orbicularis oris muscles and UV-induced dermal collagen degeneration. Fractional microneedle radiofrequency (RF) treats scars and laxity by creating vertical channels of injury in the dermis, triggering a scarless healing cascade and neocollagenesis.

OBJECTIVE

To evaluate the effect and safety of a novel fractional microneedle RF device on periorbital wrinkles based on several objective indicators.

METHODS

Eleven healthy Korean patients aged 30 to 75 years with periorbital wrinkles were included in this study. Wrinkle grades were evaluated using the Fitzpatrick wrinkle assessment scale (WAS). The melanin and erythema index, transepidermal water loss (TEWL), and three parameters for elasticity were recorded. Skin biopsies were obtained in patients who consented.

RESULTS

All patients exhibited wrinkle improvement in the lateral periorbital area, and two patients also showed efficacy in the lower eyelid area. There was a statistically significant decrease in WAS and a significant improvement in the melanin index of V4 and V5. TEWL also showed a considerable decline on V4 and V5, suggesting that the water content of the skin increased with repeated laser sessions. A peak increase in viscoelasticity and a decrease in retraction time following the first laser application were observed. In the histopathologic examination, the dermis had a denser collagen and elastin content.

CONCLUSION

Microneedle fractional RF resulted in statistically significant long-term clinical improvement of periorbital wrinkles and enhanced pigmentation and skin hydration.

Biocompatible and bioactive hydrogels of recombinant fusion elastin with low transition temperature for improved healing of UV-irradiated skin

Prolonged exposure to UV radiation can cause severe photodamage to the skin, leading to abnormal fragmentation of elastin fibers. As one of the main protein components of the dermal extracellular matrix, elastin plays a critical role in the mechanical behavior and physiological function of the skin. Animal-derived elastin has attracted extensive attention in tissue engineering, however it suffers from severe drawbacks such as a risk of virus transmission, ready degradation, and challenging quality control. Herein, we have for the first time developed a novel recombinant fusion elastin (RFE) and its cross-linked hydrogel for improved healing efficacy for UV-irradiated skin. RFE showed temperature-sensitive aggregation behavior similar to natural elastin. Compared with recombinant elastin without the fusion V-foldon domain, RFE showed a much more ordered secondary structure and lower transition temperature. Furthermore, Native-PAGE results indicated that the addition of the V-foldon domain triggered the formation of remarkable oligomers in RFE, which may result in a more ordered conformation. Tetrakis Hydroxymethyl Phosphonium Chloride (THPC) cross-linking of RFE led to the production of a fibrous hydrogel with uniform three-dimensional porous nanostructures and excellent mechanical strength. The RFE hydrogel showed superior cellular activity, significantly promoting the survival and proliferation of human foreskin fibroblast-1 (HFF-1). Studies of mice models of UV-irradiated skin demonstrated that the RFE hydrogel pronouncedly accelerated their healing process by inhibiting epidermal hyperplasia as well as boosting the regeneration of collagen and elastin fibers. The highly biocompatible and bioactive recombinant fusion elastin and its cross-linked hydrogel provide a potent treatment for photodamaged skin, which may have promising applications in dermatology and tissue engineering.

Dermal Fibroblasts as the Main Target for Skin Anti-Age Correction Using a Combination of Regenerative Medicine Methods

This article includes the data from current studies regarding the pathophysiological mechanisms of skin aging and the regenerative processes occurring in the epidermis and dermis at the molecular and cellular level, mainly, the key role of dermal fibroblasts in skin regeneration. Analyzing these data, the authors proposed the concept of skin anti-age therapy that is based on the correction of age-related skin changes by stimulating regenerative processes at the molecular and cellular level. The main target of the skin anti-age therapy is dermal fibroblasts (DFs). A variant of the cosmetological anti-age program using the combination of laser and cellular methods of regenerative medicine is presented in the paper. The program includes three stages of implementation and defines the tasks and methods of each stage. Thus, laser technologies allow one to remodel the collagen matrix and create favorable conditions for DFs functions, whereas the cultivated autologous dermal fibroblasts replenish the pool of mature DFs decreasing with age and are responsible for the synthesis of components of the dermal extracellular matrix. Finally, the use of autological platelet-rich plasma (PRP) enables to maintenance of the achieved results by stimulating DF function. It has been shown that growth factors/cytokines contained in α-granules of platelets injected into the skin bind to the corresponding transmembrane receptors on the surface of DFs and stimulate their synthetic activity. Thus, the consecutive, step-by-step application of the described methods of regenerative medicine amplifies the effect on the molecular and cellular aging processes and thereby allows one to optimize and prolong the clinical results of skin rejuvenation.

Development of Photoprotective Formulations: Influence of Formulation Composition on the SPF and Mechanical Properties

The evaluation of the vehicle formulation is important during the development of sunscreens, as it influences their efficacy. In this context, the aim of the present study was to develop photoprotective formulations and evaluate the influence of the formulation components in the sun protection factor (SPF) and physical-mechanical and sensory properties of the formulations. We evaluated four sunscreens through a 2² full factorial design in terms of concentration and emulsifier type. The design of experiments (DOE) parameters were SPF, thixotropy, and work of shear. After the screening of the formulations by DOE, the SPF values, mechanical and sensory properties, and stability were evaluated. All study formulations showed non-Newtonian pseudoplastic behavior, compatible with sunscreens, and presented SPF values above 30. The factors evaluated in DOE had significant interactions for all the analyzed parameters. The concentration of the phosphate-based emulsifier influenced the SPF parameter. The work of shear was influenced by the concentration of polyglyceryl-based emulsifier. The concentration and the type of emulsifier influenced the thixotropy. Finally, effective sunscreens were developed, and the type and concentration of emulsifiers had an influence on the SPF of the formulations. In addition, the formulations chosen by DOE were stable and showed good sensory properties.

Objective and automatic grading system of facial signs from smartphones' pictures in South African men: Validation versus dermatologists and characterization of changes with age

OBJECTIVE

To evaluate the capacity of the automatic detection system to accurately grade, from selfie pictures, the severity of eight facial signs in South African men.

METHODS

Selfie pictures (obtained from frontal and back cameras) of 281 South African men differently aged (20-70 years) were obtained and analyzed by an automatic artificial intelligence (AI)-based automatic grading system. Data were compared with the clinical gradings made by experts and dermatologists.

RESULTS

In all facial signs, both series of gradings were found highly correlated with, however, different coefficients (0.59-0.95), those of marionette lines and cheek pores being of lower values. No differences were observed between data obtained by frontal and back cameras. With age, in most cases, gradings show up to the 50-59 year age-class, linear-like changes. When compared to men of other ancestries, South African men present lower wrinkles/texture, pigmentation, and ptosis/sagging scores till 50-59 years, albeit not much different in the cheek pores sign. The early onset (mean age) of visibility of wrinkles/texture for South African men were (i.e., reaching grade >1) 39 and 45 years for ptosis/sagging.

CONCLUSION

This study completes and enlarges the previous works conducted on men of other ancestries by showing some South African specificities and slight differences with men of comparable phototypes (Afro American).

The role of sirtuins in dermal fibroblast function

The sirtuins are a family of seven proteins that perform a variety of dermatological functions and help maintain both the structure and function of the skin. More specifically, the sirtuins have been shown to be altered in multiple dermal cell types including dermal fibroblasts. The functions of dermal fibroblasts are extensive, and include playing a significant role in wound healing as well as helping to maintain the integrity of the skin. As dermal fibroblasts age, they can undergo a state of permanent cell cycle arrest, known as cellular senescence. This senescent process can occur as a result of various stressors, including oxidative stress, ultraviolet radiation -induced stress, and replicative stress. In recent years, there has been a growing interest in both enhancing the cutaneous fibroblast’s ability to facilitate wound healing and altering fibroblast cellular senescence. Thus, in this review, we examine the relationship between sirtuin signaling and dermal fibroblasts to understand how this family of proteins may modulate skin conditions ranging from the wound healing process to photocarcinogenesis associated with fibroblast senescence. Additionally, we offer supporting data from experiments examining the relationship between fibroblast senescence and sirtuin levels in an oxidative stress model indicating that senescent dermal fibroblasts exhibit diminished sirtuin levels. Furthermore, we survey the research on the role of sirtuins in specific dermatological disease states that where dermal fibroblast function has been implicated. Finally, we conclude with outlining potential clinical applications of sirtuins in dermatology. In sum, we find that the literature on the involvement of sirtuins in dermal fibroblasts is limited, with research still in its early stages. Nevertheless, intriguing preliminary findings merit additional investigation into the clinical implications of sirtuins in dermatology.

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.

Exploring the mechanism of MP gel against skin photoaging based on network pharmacology, molecular docking, and experimental validation

OBJECTIVE

Long-term and high exposure to UV radiation can lead to the development of skin photoaging diseases. Therefore, there is an ongoing need for more natural and safe drugs to prevent or treat skin photoaging diseases.

METHODS

The Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform database were used to collect the active compounds and corresponding targets of Cnidii Fructus, Arnebiae Radix, Angelicae Sinensis Radix, Poria, and Borneolum. The GeneCards database and the NCBI Gene database were used to collect the targets of skin photoaging diseases. The STRING database was used to construct a protein-protein interaction network formed by the intersecting targets of drugs and diseases. The Metascape database was applied for Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis of the targets. Molecular docking between active compounds and targets was verified by Autodock. After that, the skin photoaging model of mice was established and treated with MP gel. The skin characterization on the back of mice was observed, and the ameliorative effect of MP gel on skin photoaging was evaluated by histological and epidermal thickness assays. The MDA content and SOD activity were measured. Caspase-3 expression in mouse skin tissues was detected by immunohistochemistry, quantitative real-time polymerase chain reaction assay, and Western blot.

RESULTS

The results of network pharmacology experiments showed that the natural drugs have multi-component, multi-target therapeutic disease characteristics. The results of animal studies showed that MP gel improved the health of photoaged skin, promoted skin structural integrity, had antioxidant properties and significantly inhibited caspase-3 expression.

CONCLUSION

The experimental validation of the results of the preliminary network pharmacology analysis was carried out in animal experiments, which confirmed part of the mechanism of action of MP gel in the prevention and treatment of skin photoaging.

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.

Photoprotection in skin of color

As populations in many parts of the world are projected to become more racially diverse over the coming decades, we must better understand the unique characteristics of the skin of populations with skin of color (SOC). This review aims to highlight important physiologic and clinical considerations of photoprotection in SOC. Ultraviolet radiation and visible light affect dark and light skin differently. SOC populations have historically not been informed on photoprotection to the same degree as their light skinned counterparts. This has exacerbated dermatologic conditions in which SOC populations are disproportionately affected, such as hyperpigmentary disorders. Patients should be encouraged to utilize multiple methods of photoprotection, ranging from avoidance of sunlight during peak intensity hours, seeking shade, wearing sun-protective clothing and wide-brimmed hat, and applying sunscreen. Ideal sunscreens for SOC populations include those with UVA-PF/SPF ratios ≥ 2/3 and tinted sunscreens to protect against VL. Although there have been increased efforts recently, more research into photoprotection for SOC and targeted public education are required to disseminate photoprotection resources that are patient-centered and evidence-based.

Repeated exposure to fractional CO2 laser delays squamous cell carcinoma formation and prevents clinical and subclinical photodamage visualized by line-field confocal optical coherence tomography and histology

OBJECTIVES

Ablative fractional laser (AFL) is a well-established modality for treating ultraviolet radiation (UVR)-induced skin photodamage. We aimed to investigate the potential of AFL to delay squamous cell carcinoma (SCC) formation and prevent photodamage in a preclinical UVR-induced SCC model.

MATERIALS AND METHODS

Hairless C3.Cg-Hrhr /TifBomTac mice (n = 50) were exposed to UVR three times weekly throughout the study. UV-exposed mice were randomized to two groups that received dorsal CO2 AFL (10 mJ/mb, 10% density) or no treatment. AFL was performed every other week for a total of 16 weeks (nine treatments in total). The primary outcome was time to tumor occurrence. In a subset of mice on Day 150, prevention of clinical photodamage was assessed by examination of skin tightness and dyspigmentation. Concomitantly, assessment of subclinical photoprevention based on normalization of keratinocyte dysplasia, dermo-fiber morphology (collagen and elastin fibers), and skin thickness, was performed using line-field confocal optical coherence tomography (LC-OCT) and histology.

RESULTS

Repeated AFL treatments delayed SCC tumor development compared to UVR control mice by 12, 19, and 30 days for first, second, and third tumors, respectively (p ≤ 0.0017). Compared to UVR controls, AFL prevented photodamage both clinically and subclinically, based on LC-OCT and histology. In the epidermal layer, AFL imparted photopreventative effects including reduced dyspigmentation and keratinocyte dysplasia (1 vs. 2.5, p = 0.0079) and partial normalization of the epidermal thickness (p < 0.0001). In the dermis, AFL led to twofold greater skin tightness (p = 0.0079), improved dermo-fiber structure, and dermal thickness (p = 0.0011).

CONCLUSION

In conclusion, repeated AFL treatments of UVR-exposed skin significantly delayed SCC tumor formation and prevented clinical and imaging-assessed subclinical signs of photodamage, indicating a potential for AFL in prevention strategies for SCC and photodamage in high-risk populations.

Skin Ageing: A Progressive, Multi-Factorial Condition Demanding an Integrated, Multilayer-Targeted Remedy

Of the human organs, skin is the most visible one that displays the manifestations of ageing. It has a very intricate microanatomical structure and performs several key physiological functions. The pathophysiology of cutaneous ageing is characterized by deterioration of structural stability and functional integrity, implying a continuous reduction in maximal function and reserve capacity, as a result of the accumulating damage due to both intrinsic and extrinsic factors. Elimination of unfavorable expressions associated with facial and cutaneous ageing is the key patient demand in aesthetic dermatology. Even though the progress has been made in nonsurgical therapies like fillers and lasers, non-invasive interventions by using skin care products designed for rejuvenation at an early stage are the most popular and accessible solution among people. In this review, we have scrutinized the ageing-associated cutaneous changes at molecular, cellular and tissue levels. To optimize the ageing process towards a healthy skin, we propose an integrated, multilayer-targeted intervention, which involves both topical application of anti-ageing formulations from outside and oral supplementation from inside. Additionally, several promising naturally derived ingredients are reviewed from an anti-aging perspective. Most of them possess various bioactivities and may contribute to the development of the mentioned anti-ageing remedy.

Development of a Vascularized Human Skin Equivalent with Hypodermis for Photoaging Studies

Photoaging is an important extrinsic aging factor leading to altered skin morphology and reduced function. Prior work has revealed a connection between photoaging and loss of subcutaneous fat. Currently, primary models for studying this are in vivo (human samples or animal models) or in vitro models, including human skin equivalents (HSEs). In vivo models are limited by accessibility and cost, while HSEs typically do not include a subcutaneous adipose component. To address this, we developed an "adipose-vascular" HSE (AVHSE) culture method, which includes both hypodermal adipose and vascular cells. Furthermore, we tested AVHSE as a potential model for hypodermal adipose aging via exposure to 0.45 ± 0.15 mW/cm² 385 nm light (UVA). One week of 2 h daily UVA exposure had limited impact on epidermal and vascular components of the AVHSE, but significantly reduced adiposity by approximately 50%. Overall, we have developed a novel method for generating HSE that include vascular and adipose components and demonstrated potential as an aging model using photoaging as an example.

Organotypic cultures as aging associated disease models

Aging remains a primary risk factor for a host of diseases, including leading causes of death. Aging and associated diseases are inherently multifactorial, with numerous contributing factors and phenotypes at the molecular, cellular, tissue, and organismal scales. Despite the complexity of aging phenomena, models currently used in aging research possess limitations. Frequently used in vivo models often have important physiological differences, age at different rates, or are genetically engineered to match late disease phenotypes rather than early causes. Conversely, routinely used in vitro models lack the complex tissue-scale and systemic cues that are disrupted in aging. To fill in gaps between in vivo and traditional in vitro models, researchers have increasingly been turning to organotypic models, which provide increased physiological relevance with the accessibility and control of in vitro context. While powerful tools, the development of these models is a field of its own, and many aging researchers may be unaware of recent progress in organotypic models, or hesitant to include these models in their own work. In this review, we describe recent progress in tissue engineering applied to organotypic models, highlighting examples explicitly linked to aging and associated disease, as well as examples of models that are relevant to aging. We specifically highlight progress made in skin, gut, and skeletal muscle, and describe how recently demonstrated models have been used for aging studies or similar phenotypes. Throughout, this review emphasizes the accessibility of these models and aims to provide a resource for researchers seeking to leverage these powerful tools.

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.

Laser-assisted nanoparticle delivery to promote skin absorption and penetration depth of retinoic acid with the aim for treating photoaging

Retinoic acid (RA) is an approved treatment for skin photoaging induced by ultraviolet (UVA). Topically applied RA is mainly located in the stratum corneum (SC) with limited diffusion into the deeper strata. A delivery system capable of facilitating dermal delivery and cellular internalization for RA is critical for a successful photoaging therapy. Two delivery approaches, namely nanoparticles and laser ablation, were combined to improve RA's absorption efficacy and safety. The nanoparticle absorption enhancement by the lasers was compared between full-ablative (Er:YAG) and fractional (CO₂) modalities. We fabricated poly-L-lactic acid (PLA) and PLA/poly(lactic-co-glycolic acid) (PLGA) nanoparticles by an emulsion-solvent evaporation technique. The mean size of PLA and PLA/PLGA nanocarriers was 237 and 222 nm, respectively. The RA encapsulation percentage in both nanosystems was > 96 %. PLA and PLA/PLGA nanocarriers promoted RA skin deposition by 5- and 3-fold compared to free control. The ablative lasers further enhanced the skin deposition of RA-loaded nanoparticles, with the full-ablative laser showing greater permeation enhancement than the fractional mode. The skin biodistribution assay evaluated by confocal and fluorescence microscopies demonstrated that the laser-assisted nanoparticle delivery achieved a significant dermis and follicular accumulation. The cell-based study indicated a facile uptake of the nanoparticles into the human dermal fibroblasts. The nanoparticulate RA increased type I collagen and elastin production in the UVA-treated fibroblasts. A reduction of matrix metalloproteinase (MMP)-1 was also highlighted in the photoaging cells. The calculation of therapeutic index (TI) by multiplying collagen/elastin elevation percentage and skin deposition predicted better anti-photoaging performance in Er:YAG laser-assisted nanoparticle delivery than CO₂ laser. Nanoencapsulation of RA decreased the cytotoxicity against skin fibroblasts. In vivo skin tolerance test on a nude mouse showed less skin damage after topical application of the nanoparticles than free RA. Our results hypothesized that the laser-mediated nanoparticle delivery provided an efficient and safe use for treating 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.

The Efficacy of Intense Pulsed Light as a Treatment for Benign Pigmented Lesions on the Dorsal Hand

BACKGROUND

Intense pulsed light (IPL) is a noninvasive therapeutic option to treat benign pigmented lesions by targeting melanin.

OBJECTIVE

The purpose of this study was to assess IPL as a treatment for benign pigmented dorsal hand lesions.

MATERIALS AND METHODS

A total of fifteen subjects, 40 to 73 years old, received 3 monthly IPL treatments over the dorsal hands. Subjects followed up 1 and 3 months after treatment. At every visit, photographs were taken using the VISIA Complexion Analysis System (Canfield Scientific, Fairfield, NJ) and analyzed using the RBX Brown Spots Analysis algorithm. The Clinician Global Aesthetic Improvement Scale and Subject Global Aesthetic Improvement Scale were completed at both follow-up visits.

RESULTS

A total of fifteen subjects completed all six visits. The number of brown spots decreased 9.26% ( p = .0004) and 7.52% ( p = .0132) at each follow-up visit. The mean brown intensity decreased 6.15% ( p = .0183) and 7.67% ( p = .0178), whereas the mean contrast intensity decreased 8.88% ( p < .0001) and 6.60% ( p = .0007) 1 and 3 months after treatment, respectively. The mean Clinician Global Aesthetic Improvement Scale was 2.03 and 2.23, whereas the mean Subject Global Aesthetic Improvement Scale 1 and 3 months after treatment was 1.6 and 1.8, respectively.

CONCLUSION

Objective analysis, along with clinician and subject assessments, showed an improvement in the appearance of benign pigmented lesions in the treated area after 3 IPL treatments.

Corylin from Psoralea fructus (Psoralea corylifolia L.) protects against UV-induced skin aging by activating Nrf2 defense mechanisms

Oxidative stress damage can lead to premature skin aging or age-related skin disorders. Therefore, strategies to improve oxidative stress-induced aging are needed to protect the skin and to treat skin diseases. This study aimed to determine whether the flavonoid corylin derived from Psoralea corylifolia can prevent UV-induced skin aging and if so, to explore the potential molecular mechanisms. We found that corylin potently blocked UV-induced skin photoaging in mice by reducing oxidative stress and increasing the nuclear expression of nuclear factor-erythroid factor 2-related factor 2 Nrf2. We also found that corylin stimulated Nrf2 translocation into the nucleus and increased the delivery of its target antioxidant genes together with Kelch-like ECH-associated protein 1 (Keap1) to dissociate Nrf2. These findings indicate that corylin could prevent skin aging by inhibiting oxidative stress via Keap1-Nrf2 in mouse cells. Thus, Nrf2 activation might be a therapeutic target for preventing skin aging or skin diseases caused by aging. Our findings also provided evidence that warrants the further investigation of plant ingredients to facilitate the discovery of novel therapies targeting skin aging.

Explore the Multitarget Mechanism of Tetrahydrocurcumin preventing on UV-Induced Photoaging mouse skin

UV induced photoaging is the main external factor of skin aging. In this study, we tested the protective effects of tetrahydrocurcumin on UV-induced skin photoaging of KM mice and researched the multi-target mechanism through RNA sequencing technology. Mouse experiments show that tetrahydrocurcumin strongly changed in skin appearance, epidermal thickness, and wrinkle-related parameters in UV-irradiated mice. RNA-seq result show that we found 29 differentially expressed mRNA transcripts in UV mice relative to Ctrl rats (18 up-regulated and 11 down-regulated) and 7 significantly dysregulated mRNAs were obtained in the THC group compared to the UV group (1 up-regulated and 6 down-regulated), respectively. Spink7, Edn3, Stab2 may be the key target genes of tetrahydrocurcumin in preventing aging. Bioinformatics analysis shows that the response to muscle contraction and melanin biosynthetic GO term and Inflammation related pathway such as PPAR, MAPK would involve in effects of tetrahydrocurcumin. The results of this study indicated that tetrahydrocurcumin can improve the appearance through anti-inflammatory, improving extracellular matrix and inhibiting melanin production. It could be suggested as a protective measure in the prevention of UV-induced photoaging.

Effects of visible light on mechanisms of skin photoaging

Human skin is not only affected by ultraviolet radiation but also by visible light wavelengths emitted by sunlight, electronic devices, and light emitting diodes. Similar to the ultraviolet radiation, visible light has been implicated in photoaging. In this review, the effects of blue light, yellow light, red light, and broad visible light are discussed in relation with photoaging. Different visible light wavelengths likely contribute beneficial and deleterious effects on photoaging by way of interaction with specific photoreceptors, ROS production, and other photon-mediated reactions. Further in vivo studies are needed to determine the mechanism and action spectrum of photoaging in humans, as well as optimal photoprotection with coverage against visible light wavelengths.

Objective and automatic grading system of facial signs from selfie pictures of South African women: Characterization of changes with age and sun‐exposures

OBJECTIVE

To evaluate the capacity of the automatic detection system to accurately grade, from smartphones' selfie pictures, the severity of fifteen facial signs in South African women and their changes related to age and sun-exposure habits.

METHODS

A two-steps approach was conducted based on self-taken selfie images. At first, to assess on 306 South African women (20-69 years) enrolled in Pretoria area (25.74°S, 28.22°E), age changes on fifteen facial signs measured by an artificial intelligence (AI)-based automatic grading system previously validated by experts/dermatologists. Second, as these South African panelists were recruited according to their usual behavior toward sun-exposure, that is, nonsun-phobic (NSP, N = 151) and sun-phobic (SP, N = 155) and through their regular and early use of a photo-protective product, to characterize the facial photo-damages.

RESULTS

(1) The automatic scores showed significant changes with age, by decade, of sagging and wrinkles/texture (p < 0.05) after 20 and 30 years, respectively. Pigmentation cluster scores presented no significant changes with age whereas cheek skin pores enlarged at a low extent with two plateaus at thirties and fifties. (2) After 60 years, a significantly increased severity of wrinkles/texture and sagging was observed in NSP versus SP women (p < 0.05). A trend of an increased pigmentation of the eye contour (p = 0.06) was observed after 50 years.

CONCLUSION

This work illustrates specific impacts of aging and sun-exposures on facial signs of South African women, when compared to previous experiments conducted in Europe or East Asia. Results significantly confirm the importance of sun-avoidance coupled with photo-protective measures to avoid long-term skin damages. In inclusive epidemiological studies that aim at investigating large human panels in very different contexts, the AI-based system offers a fast, affordable and confidential approach in the detection and quantification of facial signs and their dependency with ages, environments, and lifestyles.

Exploration of the Molecular Mechanisms Underlying the Anti-Photoaging Effect of Limosilactobacillus fermentum XJC60

Although lactic acid bacteria (LAB) were shown to be effective for preventing photoaging, the underlying molecular mechanisms have not been fully elucidated. Accordingly, we examined the anti-photoaging potential of 206 LAB isolates and discovered 32 strains with protective activities against UV-induced injury. All of these 32 LABs exhibited high levels of 2,2-diphenyl-picrylhydrazyl, as well as hydroxyl free radical scavenging ability (46.89–85.13% and 44.29–95.97%, respectively). Genome mining and metabonomic verification of the most effective strain, Limosilactobacillus fermentum XJC60, revealed that the anti-photoaging metabolite of LAB was nicotinamide (NAM; 18.50 mg/L in the cell-free serum of XJC60). Further analysis revealed that LAB-derived NAM could reduce reactive oxygen species levels by 70%, stabilize the mitochondrial membrane potential, and increase the NAD⁺/NADH ratio in UV-injured skin cells. Furthermore, LAB-derived NAM downregulated the transcript levels of matrix metalloproteinase (MMP)-1, MMP-3, interleukin (IL)-1β, IL-6, and IL-8 in skin cells. In vivo, XJC60 relieved imflammation and protected skin collagen fiber integrity in UV-injured Guinea pigs. Overall, our findings elucidate that LAB-derived NAM might protect skin from photoaging by stabilizing mitochondrial function, establishing a therotical foundation for the use of probiotics in the maintenance of skin health.

Phytocomplex of a Standardized Extract from Red Orange (Citrus sinensis L. Osbeck) against Photoaging

Excessive exposure to solar radiation is associated with several deleterious effects on human skin. These effects vary from the occasional simple sunburn to conditions resulting from chronic exposure such as skin aging and cancers. Secondary metabolites from the plant kingdom, including phenolic compounds, show relevant photoprotective activities. In this study, we evaluated the potential photoprotective activity of a phytocomplex derived from three varieties of red orange (Citrus sinensis (L.) Osbeck). We used an in vitro model of skin photoaging on two human cell lines, evaluating the protective effects of the phytocomplex in the pathways involved in the response to damage induced by UVA-B. The antioxidant capacity of the extract was determined at the same time as evaluating its influence on the cellular redox state (ROS levels and total thiol groups). In addition, the potential protective action against DNA damage induced by UVA-B and the effects on mRNA and protein expression of collagen, elastin, MMP1, and MMP9 were investigated, including some inflammatory markers (TNF-α, IL-6, and total and phospho NFkB) by ELISA. The obtained results highlight the capacity of the extract to protect cells both from oxidative stress—preserving RSH (p < 0.05) content and reducing ROS (p < 0.01) levels—and from UVA-B-induced DNA damage. Furthermore, the phytocomplex is able to counteract harmful effects through the significant downregulation of proinflammatory markers (p < 0.05) and MMPs (p < 0.05) and by promoting the remodeling of the extracellular matrix through collagen and elastin expression. This allows the conclusion that red orange extract, with its strong antioxidant and photoprotective properties, represents a safe and effective option to prevent photoaging caused by UVA-B exposure.

Facial Skin Aging: key concepts and overview of processes

Introduction

The face is a cosmetically sensitive region where the process of ageing is most clearly manifested. With increased focus on anti‐ageing and longevity, more anti‐senescent treatments are being proposed despite limited evidence. This study outlines the pathways and mechanisms underpinning the biological process of ageing in the face.

Methods

Comprehensive searches of MEDLINE, EMBASE, Cochrane Library and CINAHL from inception to 2020. Inclusion criteria included all empirical human research studies specific to facial ageing features, written in the English language.

Results

A total of 65 papers met inclusion criteria for analysis. Pathways were subdivided into intrinsic and extrinsic senescence mechanisms. Intrinsic pathways included genetics, generation of reactive oxygen species and hormonal changes. Extrinsic pathways included photoageing and damage to skin layers. The combined intrinsic and extrinsic pathway alterations result in wrinkles, higher laxity, slackness and thinning of the skin. Skin functions such as barrier immune function, wound healing, thermoregulation and sensory function are also impaired.

Conclusion

The ageing process is unique to the individual and depends on the interplay between an individual's genetics and external environmental factors. Through understanding the molecular and cellular mechanisms, an appreciation of the consequent structural and functional changes can be achieved. Based on this knowledge, further research can focus on how to slow or impede the ageing process and identify specific targets to develop and evolve new treatment strategies.

Theragra chalcogramma Hydrolysate, Rich in Gly-Leu-Pro-Ser-Tyr-Thr, Alleviates Photoaging via Modulating Deposition of Collagen Fibers and Restoration of Extracellular Components Matrix in SD Rats

Excessive exposure of the skin to ultraviolet irradiation induces skin photoaging, which seriously deteriorates the barrier functions of skin tissue, and even causes skin damages and diseases. Recently, dietary supplements from marine sources have been found to be useful in modulating skin functions and can be used to alleviate photoaging. Herein, the low-molecular-weight hydrolysates with a photoaging-protection effect were prepared by enzymatic hydrolysis from Theragra chalcogramma (TCH), and the potential mechanism were subsequently explored. The results revealed that TCH desirably improved the barrier functions of photoaged skin and stimulated the deposition of ECM components Col I, Hyp, and HA in the dermal layer. Histologically, TCH reduced the epidermal hyperplasia and restored the impaired architectures in a dose-dependent manner. Meanwhile, the activity of matrix metalloproteinase-1 (MMP-1) in photoaging skin was inhibited, and the expression levels of elastin and fibrillin-1 were elevated accordingly after TCH administration, and the significant improvements were observed at high-dose level (p < 0.05). Taken together, the efficacy of TCH against skin photoaging is highly associated with the regulation on ECM metabolism and the repairing of damaged mechanical structure.

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.

Topical tretinoin for treating photoaging: A systematic review of randomized controlled trials

Aging, an inevitable and continuous process in one's lifetime, has all along been a focus of interest, especially for women, yet photoaging treatment to slow the process remains challenging. Recent studies have demonstrated the potency of topical tretinoin in the treatment of photoaging. Tretinoin, a metabolite of retinoids, shows prominent efficacy to regulate proliferation and differentiation of epidermal cells and induce new collagen formation.

Objective

This review aims to study the current evidence on topical tretinoin for photoaging treatment.

Methods

A systematic search of the literature was performed from Medline, Cochrane Central, Embase, and PubMed databases for published articles in the past 20 years. Only randomized controlled trials investigating tretinoin for photoaging treatment were included in our review.

Results

A total of 180 studies were initially examined, of which 7 randomized controlled trials were included in this review. Four studies included only women as their participants, while the rest demonstrated women as their majority subjects. All studies that indicated topical tretinoin were safe and well tolerated in all patients. Topical tretinoin dosage varied from 0.025% to 5% while duration of treatment ranged from 3 months up to 24 months. With regard to efficacy, all studies consistently reported that topical tretinoin was efficacious in improving clinical appearance of photoaging in terms of wrinkling, mottled hyperpigmentation, sallowness, and lentigines as early as 1 month and lasted after 24 months.

Limitations

Different tretinoin formulas used, different outcome parameters, and limited recent studies on topical tretinoin cause lack of uniformity in the evidences.

Conclusion

Topical tretinoin is a safe and effective therapeutic modality for long-term treatment of photoaging. Further research is required to compare dose-ranging topical tretinoin to other agents to provide the best treatment strategy for photoaged skin.

Chemical Distance Measurement and System Pharmacology Approach Uncover the Novel Protective Effects of Biotransformed Ginsenoside C-Mc against UVB-Irradiated Photoaging

Long-term exposure to ultraviolet light induces photoaging and may eventually increase the risk of skin carcinogenesis. Rare minor ginsenosides isolating from traditional medicine Panax (ginseng) have shown biomedical efficacy as antioxidation and antiphotodamage agents. However, due to the difficulty of component extraction and wide variety of ginsenoside, the identification of active antiphotoaging ginsenoside remains a huge challenge. In this study, we proposed a novel in silico approach to identify potential compound against photoaging from 82 ginsenosides. Specifically, we calculated the shortest distance between unknown and known antiphotoaging ginsenoside set in the chemical space and applied chemical structure similarity assessment, drug-likeness screening, and ADMET evaluation for the candidates. We highlighted three rare minor ginsenosides (C-Mc, Mx, and F2) that possess high potential as antiphotoaging agents. Among them, C-Mc deriving from American ginseng (Panax quinquefolius L.) was validated by wet-lab experimental assays and showed significant antioxidant and cytoprotective activity against UVB-induced photodamage in human dermal fibroblasts. Furthermore, system pharmacology analysis was conducted to explore the therapeutic targets and molecular mechanisms through integrating global drug-target network, high quality photoaging-related gene profile from multiomics data, and skin tissue-specific expression protein network. In combination with in vitro assays, we found that C-Mc suppressed MMP production through regulating the MAPK/AP-1/NF-κB pathway and expedited collagen synthesis via the TGF-β/Smad pathway, as well as enhanced the expression of Nrf2/ARE to hold a balance of endogenous oxidation. Overall, this study offers an effective drug discovery framework combining in silico prediction and in vitro validation, uncovering that ginsenoside C-Mc has potential antiphotoaging properties and might be a novel natural agent for use in oral drug, skincare products, or functional food.