Angiogenesis in skin aging and photoaging

The role and mechanism of engineered nanovesicles derived from hair follicle mesenchymal stem cells in the treatment of UVB-induced skin photoaging

BACKGROUND

Extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) are effective in the treatment of skin photoaging; however, their low yield and functional decline with passage progression limit their clinical application. Cell-derived nanovesicles (CNVs) are potential alternatives that can address the limitations of EVs derived from MSCs and are conducive to clinical transformations. Hair follicle mesenchymal stem cells (HFMSCs), a type of MSCs, have demonstrated the function of repairing skin tissues; nevertheless, the efficacy of CNVs from HFMSCs (HFMSC-CNVs) in the treatment of skin photoaging remains unclear. Therefore, ultraviolet radiation B (UVB)-induced photoaging nude mice and human dermal fibroblasts (HDFs) were used as experimental models to investigate the therapeutic effects of HFMSC-CNVs in photoaging models.

METHODS

HFMSC-CNVs were successfully prepared using the mechanical extrusion method. UVB-induced nude mice and HDFs were used as experimental models of photoaging. Multiple approaches, including hematoxylin-eosin and Masson staining, immunohistochemistry, immunofluorescence, detection of reactive oxygen species (ROS), flow cytometry, western blotting, and other experimental methods, were combined to investigate the possible effects and mechanisms of HFMSC-CNVs in the treatment of skin photoaging.

RESULTS

In the nude mouse model of skin photoaging, treatment with HFMSC-CNVs reduced UVB-induced skin wrinkles (p < 0.05) and subcutaneous capillary dilation, alleviated epidermis thickening (p < 0.001), and dermal thinning (p < 0.001). Furthermore, HFMSC-CNVs upregulated proliferating cell nuclear antigen (PCNA) expression (p < 0.05) and decreased the levels of ROS, β-galactosidase (β-Gal), and CD86 (p < 0.01). In vitro experiments, treatment with HFMSC-CNVs enhanced the cellular activity of UVB-exposed HDFs (p < 0.05), and reduced ROS levels and the percentage of senescent cells (p < 0.001), and alleviated cell cycle arrest (p < 0.001). HFMSC-CNVs upregulated the expression of Collagen I (Col I), SMAD2/3, transforming growth factor beta (TGF-β), catalase (CAT), glutathione peroxidase-1 (GPX-1), and superoxide dismutase-1 (SOD-1) (p < 0.05) and downregulated the expression of cycle suppressor protein (p53), cell cycle suppressor protein (p21), and matrix metalloproteinase 3 (MMP3) (p < 0.05).

CONCLUSION

Conclusively, the anti-photoaging properties of HFMSC-CNVs were confirmed both in vivo and in vitro. HFMSC-CNVs exert anti-photoaging effects by alleviating cell cycle arrest, decreasing cellular senescence and macrophage infiltration, promoting cell proliferation and extracellular matrix (ECM) production, and reducing oxidative stress by increasing the activity of antioxidant enzymes.

Human Skin Aging and the Anti-Aging Properties of Retinol

The skin is the most-extensive and -abundant tissue in the human body. Like many organs, as we age, human skin experiences gradual atrophy in both the epidermis and dermis. This can be primarily attributed to the diminishing population of epidermal stem cells and the reduction in collagen, which is the primary structural protein in the human body. The alterations occurring in the epidermis and dermis due to the aging process result in disruptions to the structure and functionality of the skin. This creates a microenvironment conducive to age-related skin conditions such as a compromised skin barrier, slowed wound healing, and the onset of skin cancer. This review emphasizes the recent molecular discoveries related to skin aging and evaluates preventive approaches, such as the use of topical retinoids. Topical retinoids have demonstrated promise in enhancing skin texture, diminishing fine lines, and augmenting the thickness of both the epidermal and dermal layers.

Assessment of efficacy of carboxytherapy in management of skin aging through evaluation of gene expression profile: a 2-split randomized clinical trial

Skin aging is a continuous and irreversible process which results in impairment of the skin role as barrier against all aggressive exogenous factors. It mainly manifests by photoaging, laxity, sagging, wrinkling, and xerosis. Carboxytherapy is considered as a safe, minimally invasive modality used for rejuvenation, restoration, and recondition of the skin. In the current study, the efficacy of carboxytherapy in the treatment of skin aging was assessed through investigation of gene expression profile for Coll I, Coll III, Coll IV, elastin, FGF, TGF-β1, and VEGF. Our study is a 2-split clinical trial in which carboxytherapy was performed on one side of the abdomen in 15 cases with intrinsically skin aging manifestations weekly for 10 sessions, while the other side of the abdomen was left without treatment. Two weeks after the last session, skin biopsies were taken from both the treated and control sides of the abdomen in order to assess gene expression profile by qRT-PCR. The analysis of gene expression levels for all of Coll I, Coll III, Coll IV, elastin, TGF-β1, FGF and VEGF genes showed a statistically significant difference between the interventional and control groups. The findings for all of these seven genes showed increase in the interventional group, among which Coll IV, VEGF, FGF, and elastin showed the higher mean changes. Our study confirmed the effectiveness of carboxytherapy in treating and reversing the intrinsically aging skin.Clinical Trial Registration Code and Date of Registration: ChiCTR2200055185; 2022/1/2.

Hydroquinone cream-based polymer microneedle roller for the combined treatment of large-area chloasma

Melasma is a common hyperpigmented skin condition that occurs on the face and other areas prone to light exposure, seriously affecting people's quality of life. Microneedle, a new type of transdermal drug delivery device, can significantly improve skin permeability. In this study, we designed and fabricated a polymer microneedle roller (PMR) using a mold hot pressing method, and established a mouse model of melasma induced by ultraviolet radiation. The dynamometer and insertion test of MNs into parafilm and skin of mice indicates that the MNs have sufficient mechanical properties to insert parafilm and skin of mice. The two methods (apply hydroquinone cream (HQC) directly and pre-treat with PMR before applying HQC) were used to treat melasma. From the results of skin surface observation, determination of superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in skin and liver tissues, histological observation, and skin Optical coherence tomography (OCT), we confirmed both the two methods had a therapeutic effect while the PMR pretreatment group exhibited a better therapeutic effect. In addition, there were statistical differences between the UV group (P < 0.05). Together these results indicated that the MNs may be promising in future clinical applications in improving the UV irradiation-induced pigmentation like melisma.

Dynamic Optical Coherence Tomography: A Non-Invasive Imaging Tool for the Distinction of Nevi and Melanomas

Along with the rising melanoma incidence in recent decades and bad prognoses resulting from late diagnoses, distinguishing between benign and malignant melanocytic lesions has become essential. Unclear cases may require the aid of non-invasive imaging to reduce unnecessary biopsies. This multicentric, case-control study evaluated the potential of dynamic optical coherence tomography (D-OCT) to identify distinguishing microvascular features in nevi. A total of 167 nevi, including dysplastic ones, on 130 participants of all ages and sexes were examined by D-OCT and dermoscopy with a histological reference. Three blinded analyzers evaluated the lesions. Then, we compared the features to those in 159 melanomas of a prior D-OCT study and determined if a differential diagnosis was possible. We identified specific microvascular features in nevi and a differential diagnosis of melanomas and nevi was achieved with excellent predictive values. We conclude that D-OCT overcomes OCT´s inability to distinguish melanocytic lesions based on its focus on microvascularization. To determine if an addition to the gold standard of a clinical-dermoscopic examination improves the diagnosis of unclear lesions, further studies, including a larger sample of dysplastic nevi and artificial intelligence, should be conducted.

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.

The landscape of photoaging: From bench to bedside in a bibliometric analysis

Background

Bibliometric software exists as a platform providing multiple algorithms to process the data to suffice diverse goals. Interpretation of the result must be based on insight into the meaning of the original data and the algorithm used. Medical Subject Headings (MeSH) terms represent the macro-level meaning of topics, keywords that commonly reflect the micro-level aspects.

Objective

This study attempts to investigate the landscape of photoaging in the recent two decades by using bibliometric analysis.

Methods

Published studies of photoaging were obtained from PubMed and Web of Science Core Collection (WoSCC) from 2000 to 2020. Basic bibliometric information was generated by WoSCC. Major MeSH terms were performed in cluster analysis and displayed as a hierarchical form to induce knowledge structure, detection algorithm on keywords was presented as a timeline form to obtain hotspots, and institutional clusters were labeled with keywords to achieve institutional characteristics.

Results

A total of 2,727 and 2,705 studies were identified in PubMed and WoSCC, respectively. The number of photoaging-related studies at 3-year intervals grew steadily. The studies were performed in about 80 countries/regions. The highly frequent major MeSH terms were distributed in seven clusters, reflecting the etiology, pathophysiology, treatment, and prevention of photoaging. The hotspots changed as time went on, and the hotspots in recent 5 years were mitogen-activated protein kinase (MAPK), nuclear factor erythroid-derived 2-like 2 (Nrf2), and antioxidant activity. The highly productive institutions labeling in the top four clusters were Seoul National University, University of Michigan, China Medical University, and Harvard University, with corresponding keywords of UVB, retinoic acid, Nrf2, and rejuvenation.

Conclusions

This study built a knowledge structure of pathophysiology, treatment and prevention of photoaging, and identified recent hotspots of MAPK, Nrf2, and antioxidant activity. We provide a landscape of photoaging, from the bench (pathophysiology) to bedside (treatment, prevention), and pave the way for future research.

Exosomes Derived from Secretome Human Umbilical Vein Endothelial Cells (Exo-HUVEC) Ameliorate the Photo-Aging of Skin Fibroblast

Purpose

This is an in-vitro experimental study to analyze the effect of Exo-HUVEC on endothelial cell (CD31), cell proliferation, matrix metalloproteinase 1 (MMP-1) and collagen type 1 on irradiated fibroblast with UVB as photo-aging model.

Patients and Methods

Fibroblast cultures were divided into 5 groups, namely without UVB exposure, UVB exposure 600mJ/cm2 for 80 seconds as photo-aging model, and UVB exposure +Exo-HUVEC exposure 0.1%, 0.5% and 1%. The endothelial cell was stained with a CD31 marker, MMP-1 were examined with ELISA, cell proliferation is detected using an MTT assay; meanwhile, collagen type 1 deposition and endothelial cell were measured using flowcytometry.

Results

This study found positive endothelial cell marker CD31. Significant difference was found in cell proliferation, MMP-1 and collagen type 1 level between the control group with UVB irradiation and the treatment group with Exo-HUVEC (p < 0.05).

Conclusion

Exo-HUVEC significantly increases cell proliferation and collagen type 1 level, while decrease MMP-1 levels on irradiated fibroblast; therefore, Exo-HUVEC ameliorate the photo-aging of skin fibroblast.

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.

Paclitaxel-Induced Epidermal Alterations: An In Vitro Preclinical Assessment in Primary Keratinocytes and in a 3D Epidermis Model

Paclitaxel is a microtubule-stabilizing chemotherapeutic agent approved for the treatment of ovarian, non-small cell lung, head, neck, and breast cancers. Despite its beneficial effects on cancer and widespread use, paclitaxel also damages healthy tissues, including the skin. However, the mechanisms that drive these skin adverse events are not clearly understood. In the present study, we demonstrated, by using both primary epidermal keratinocytes (NHEK) and a 3D epidermis model, that paclitaxel impairs different cellular processes: paclitaxel increased the release of IL-1α, IL-6, and IL-8 inflammatory cytokines, produced reactive oxygen species (ROS) release and apoptosis, and reduced the endothelial tube formation in the dermal microvascular endothelial cells (HDMEC). Some of the mechanisms driving these adverse skin events in vitro are mediated by the activation of toll-like receptor 4 (TLR-4), which phosphorylate transcription of nuclear factor kappa B (NF-κb). This is the first study analyzing paclitaxel effects on healthy human epidermal cells with an epidermis 3D model, and will help in understanding paclitaxel's effects on the skin.

Structural and Functional Changes and Possible Molecular Mechanisms in Aged Skin

Skin aging is a complex process influenced by intrinsic and extrinsic factors. Together, these factors affect the structure and function of the epidermis and dermis. Histologically, aging skin typically shows epidermal atrophy due to decreased cell numbers. The dermis of aged skin shows decreased numbers of mast cells and fibroblasts. Fibroblast senescence contributes to skin aging by secreting a senescence-associated secretory phenotype, which decreases proliferation by impairing the release of essential growth factors and enhancing degradation of the extracellular matrix through activation of matrix metalloproteinases (MMPs). Several molecular mechanisms affect skin aging including telomere shortening, oxidative stress and MMP, cytokines, autophagic control, microRNAs, and the microbiome. Accumulating evidence on the molecular mechanisms of skin aging has provided clinicians with a wide range of therapeutic targets for treating aging skin.

Hesperidin Inhibits UVB-Induced VEGF Production and Angiogenesis via the Inhibition of PI3K/Akt Pathway in HR-1 Hairless Mice

Hesperidin is a citrus flavanone glycoside with potent anti-inflammatory effects that interferes with UVB-stimulated angiogenesis in skin, but its molecular mechanisms of action remain unclear. Here, we investigated the effects of hesperidin on UVB-induced angiogenesis in HR-1 hairless mice. We found hesperidin treatment inhibited skin neovascularization skin induced by repetitive UVB light exposure. Exposure to UVB radiation induces the expression of vascular endothelial growth factor (VEGF), matrix metalloproteinase-13 (MMP-13), and MMP-9, but we found all of these were inhibited by treatment with hesperidin. Using immunohistochemistry and Western blotting, we also found hesperidin inhibited the increase in hypoxia inducible factor-1 (HIF-1)α expression induced by UVB exposure. After discovering that UVB induces VEGF expression via the phosphoinositide 3-kinase (PI3K)/Akt signaling pathways, we found hesperidin reduces UVB-induced VEGF expression by inhibiting UVB-induced PI3K activity. This, in turn, reduces the UVB-induced Akt/p70S6K phosphorylation in human primary keratinocytes and fibroblast cells. Because it affects the mediators of angiogenesis, our data suggest hesperidin has an anti-angiogenic effect on the pathologic skin neovascularization induced by UVB light. Thus, hesperidin may prove useful in the treatment of skin injuries caused by UVB light exposure.

Protective effects of fucoidan purified from Undaria pinnatifida against UV-irradiated skin photoaging

Background

Exposure to ultraviolet (UV) radiation (UVB and UVA) is the most well-known extrinsic factor that induces skin aging. Fucoidan has been shown to possess antiphotoaging effects against UV irradiation and can be used as an ingredient in the pharmaceutical industry. The present study evaluated the photoprotective effect of fucoidan purified from Undaria pinnatifida (UPF) on UV-induced skin photoaging and explored its potential molecular mechanism.

Methods

To evaluate the effect of UPF on UV-induced skin aging, HaCaT cells and HFF-1 cells were pretreated with or without UPF and then exposed to UVB and UVA radiation, respectively, and the levels of cellular senescence, reactive oxygen species (ROS) production and mitochondrial dysfunction were evaluated. The mitochondrial ROS (mROS) was stained through MitoSOX, and the confocal microscope was used to capture the images. For further exploration of AMPK/SIRT-1/PGC-1α signaling, western blot was employed.

Results

The results demonstrated that pretreatment of HaCaT and HFF-1 cells with UPF ameliorated cellular senescence, ROS and mROS overproduction, and mitochondrial dysfunction caused by UV exposure. This research also revealed that UPF could activate the AMPK/SIRT-1/PGC-1α signaling pathway to promote mitochondrial biogenesis.

Conclusions

UPF can ameliorate UV-induced skin photoaging through inhibition of ROS production via the alleviation of mitochondrial dysfunction by regulating the SIRT-1/PGC-1α signaling pathway.

Anti-Photoaging and Potential Skin Health Benefits of Seaweeds

The skin health benefits of seaweeds have been known since time immemorial. They are known as potential renewable sources of bioactive metabolites that have unique structural and functional features compared to their terrestrial counterparts. In addition, to the consciousness of green, eco-friendly, and natural skincare and cosmetics products, their extracts and bioactive compounds such as fucoidan, laminarin, carrageenan, fucoxanthin, and mycosporine like amino acids (MAAs) have proven useful in the skincare and cosmetic industries. These bioactive compounds have shown potential anti-photoaging properties. Furthermore, some of these bioactive compounds have been clinically tested and currently available in the market. In this contribution, the recent studies on anti-photoaging properties of extracts and bioactive compounds derived from seaweeds were described and discussed.

Angiogenesis Is Differentially Modulated by Platelet-Derived Products

Platelet-derived preparations are being used in clinic for their role in tissue repair and regenerative processes. The release of platelet-derived products such as autologous growth factors, cytokines and chemokines can trigger therapeutic angiogenesis. In this in vitro study, we evaluated and compared the ability of three platelet-derived preparations: platelet-rich-plasma (PRP), PRP-hyaluronic acid (PRP-HA) and platelet lysates (PL) at various concentrations (5–40%) to modulate human umbilical vein endothelial cells (HUVEC) biological effects on metabolism, viability, senescence, angiogenic factors secretion and angiogenic capacities in 2D (endothelial tube formation assay or EFTA) and in 3D (fibrin bead assay or FBA). HUVEC exocytosis was stimulated with PRP and PRP-HA. Cell viability was strongly increased by PRP and PRP-HA but mildly by PL. The three preparations inhibit HUVEC tube formation on Matrigel, while PRP enhanced the complexity of the network. In the fibrin bead assay (FBA), PRP and PRP-HA stimulated all steps of the angiogenic process resulting in massive sprouting of a branched microvessel network, while PL showed a weaker angiogenic response. Secretome profiling revealed modulation of 26 human angiogenic proteins upon treatment with the platelet derived preparations. These in vitro experiments suggest that PRP and PRP-HA are effective biological therapeutic tools when sustained therapeutic angiogenesis is needed.

Skin and Nerve Neovascularization in POEMS Syndrome: Insights From a Small Cohort

Polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, skin changes (POEMS) syndrome is a rare systemic disorder linked to plasma cell dyscrasia and is related to elevation of vascular endothelial growth factor (VEGF). Diagnosis is still challenging and pathophysiology unclear. Because VEGF drives neovascularization, we investigated skin and nerve vascularization in 6 patients with POEMS syndrome compared with 5 control groups of polyneuropathies and healthy subjects (n = 104) from the University Hospital of Limoges between 2009 and 2018. We evaluated loss of small and large fibers in these patients. Skin and nerve vascularization were quantified manually on immunofluorescence using vessel staining (anti-α-SMA antibody). Dermal vascularization was significantly higher in POEMS syndrome than in other groups, but unrelated to loss of small fibers and VEGF. Perineurial vascularization was higher in POEMS syndrome than in healthy controls, and was related to loss of large fibers and VEGF level. Our study highlights the existence of neovascularization in skin of patients with this rare disorder. These data suggest that skin neovascularization could be an additional biomarker to help in the diagnosis and understanding of POEMS syndrome. Moreover, nerve neovascularization, driven by VEGF overexpression, may play a role in the pathophysiology of large fiber loss in this condition.

Cosmeceuticals: The Principles and Practice of Skin Rejuvenation by Nonprescription Topical Therapy

Background

Aesthetic practice relies on a harmonious relationship between medicine and commerce. Bridging the gap is a large number of skincare products that make therapeutic claims while avoiding the regulatory framework of pharmaceuticals. In this gray area, clinicians find themselves poorly disposed to counsel patients wisely as the industry is expanding faster than empirical evidence of efficacy and safety can be acquired. To serve our patients and engage with industry, we must understand the theoretical principles and evaluate the clinical evidence in practice.

Objectives

The purpose of this paper is to classify cosmeceuticals by method of action, explain how they work in principle with reference to skin aging, and evaluate the clinical evidence for them.

Methods

A literature and cosmetic clinic website search was conducted to establish a list of the most commonly advertised cosmeceuticals, and a peer-reviewed literature search was then conducted to establish the clinical evidence for them.

Results

A huge number of cosmeceuticals are marketed for skin rejuvenation but almost invariably they fall into 1 of 4 categories. These include the induction of tissue repair mechanisms, inflammatory modulation, scavenging of reactive oxygen species, or a combination of the 3. With the exception of retinol derivatives and hydroxy acids, the clinical evidence is limited, despite promising preclinical evidence for several cosmeceuticals.

Conclusions

Cosmeceuticals reside within a highly competitive ecosystem and are often brought to market based on preclinical, not clinical evidence. Success and failure will largely be governed by the establishment of clinical evidence in retrospect.

Assessment of Laser Effects on Skin Rejuvenation

Laser skin resurfacing has changed the approach of facial skin rejuvenation over the past decade. This article evaluates the laser effects on skin rejuvenation by the assessment of laser characteristics and histological and molecular changes, accompanied by the expression of proteins during and after laser-assisted rejuvenation of skin. It is important to note that different layers of skin with different cells are normally exposed to the sun's UV radiation which is the most likely factor in aging and damaging healthy skin. To identify the expression of proteins, using validated databases and reviewing existing data could reveal altered proteins which could be analyzed and mapped to investigate their expression and their different effects on cell biological responses. In this regard, proteomics data can be used for better investigation of the changes in the proteomic profile of the treated skin. Different assessments have revealed the survival and activation of fibroblasts and new keratinocytes with an increase of collagen and elastin fibers in the dermis and the reduction of matrix metalloproteinases (MMPs) and heat shock proteins (HSPs) as a result of different low-power laser therapies of skin. There are a wide range of biological effects associated with laser application in skin rejuvenation; therefore, more safety considerations should be regarded in the application of lasers in skin rejuvenation.

Rosacea: a wholistic review and update from pathogenesis to diagnosis and therapy

Rosacea is a chronic inflammatory disorder of the central face with multiple overlapping presentations. Recent advancements are reshaping our understanding of rosacea from both a pathophysiologic perspective and clinical approach to therapy, introducing novel agents that have improved patient outcomes and reduced morbidity. In this article, we aim to outline the advancements in understanding, diagnosing, and managing rosacea and to familiarize physicians with the literature, thereby allowing us to better practice safe and effective medicine.

Royal jelly regulates the proliferation of human dermal microvascular endothelial cells through the down-regulation of a photoaging-related microRNA

Although royal jelly is believed to prevent skin aging, the underlying mechanism is not known in detail. In the present study, we investigated the plausibility of the involvement of microRNAs in the manifestation of this effect of royal jelly. The expression of microRNAs was determined by PCR array analysis and real-time PCR and the number of cells was counted with a cell counter. Using PCR array, we identified four microRNAs that were downregulated by royal jelly in cultured human dermal microvascular endothelial cells (HDMEC). Upon comparison of the expression of the four microRNAs between young and senescent facial skin, miR-129-5p was found to be significantly upregulated in senescent skin. Consistently, the expression of miR-129-5p in HDMEC was significantly increased by UVB radiation, suggesting that this microRNA is related to photoaging. The royal jelly treatment increased the number of HDMEC. Furthermore, forced overexpression of miR-129-5p resulted in significant decrease in the number of HDMEC, and its forced downregulation increased the number of cells. The number and density of vessels is reported to be decreased in aged skin. Our results indicate that miR-129-5p is induced in damaged endothelial cells upon exposure to UV radiation, which decreases the cell number. Furthermore, administration of royal jelly downregulated the expression of miR-129-5p in endothelial cells, and might prevent skin aging by maintaining the number of cells. The present study elucidates the mechanism of vessel aging caused by UV exposure and the anti-aging effects of royal jelly through the involvement of microRNA.

Overview of biological mechanisms of human carcinogens

This review summarizes the carcinogenic mechanisms for 109 Group 1 human carcinogens identified as causes of human cancer through Volume 106 of the IARC Monographs. The International Agency for Research on Cancer (IARC) evaluates human, experimental and mechanistic evidence on agents suspected of inducing cancer in humans, using a well-established weight of evidence approach. The monographs provide detailed mechanistic information about all carcinogens. Carcinogens with closely similar mechanisms of action (e.g. agents emitting alpha particles) were combined into groups for the review. A narrative synopsis of the mechanistic profiles for the 86 carcinogens or carcinogen groups is presented, based primarily on information in the IARC monographs, supplemented with a non-systematic review. Most carcinogens included a genotoxic mechanism.

Clinical evaluation of the safety and efficacy of a timosaponin A-III-based antiwrinkle agent against skin aging

BACKGROUND

Timosaponin A-III (TA-III) is known to exist in the medicinal herb of Anemarrhena asphodeloides as one of major chemical components.

AIMS

The photoprotective properties of TA-III on UVB-exposed HaCaT cells were evaluated on the antiwrinkle effects and skin safety in terms of clinical trial.

METHODS

The level of matrix metalloproteinase (MMP)-1, tissue inhibitor of metalloproteinases (TIMPs), and pro-inflammatory cytokines were measured in HaCaT cells following UVB irradiation. To evaluate the clinical safety of an agent containing 0.25% of TA-III for use on human skin. Female subjects (n = 21) between the ages of 43 and 55 who met the criteria for subject selection were selected. They were beginning to form or had already formed wrinkles.

RESULTS

UVB irradiation increased MMP-1 expression and pro-inflammatory cytokines. These increases were attenuated by TA-III pretreatment of UVB-exposed HaCaT cells. We found that the agent containing 0.25% of TA-III ameliorated skin wrinkling. A comparison between groups showed that wrinkle parameters were significantly reduced after 12 weeks of product use (P < 0.05). According to skin safety result, TA-III showed no dermatological toxicity was found in participants.

CONCLUSIONS

In conclusion, TA-III could provide protection against photoaging and daily application of TA-III for 12 weeks significantly reduced signs of facial aging by limiting wrinkle formation.

Antiphotoaging and Antimelanogenesis Properties of Ginsenoside C-Y, a Ginsenoside Rb2 Metabolite from American Ginseng PDD-ginsenoside

Ginsenosides are compounds responsible for the primary pharmacological effects of American ginseng. Compound-Y (C-Y) is a minor ginsenoside and a metabolite of Panax ginseng. In this study, we investigated the protective effect of ginsenoside UVB-irradiated NHDFs and its potential for use as an antihyperpigmentation agent through ginsenoside C-Y as a functional food and cosmetic ingredient. Ginsenoside C-Y is a natural antioxidant isolated from the American ginseng PDD-ginsenoside. Our data showed that ginsenoside C-Y block UVB-exposed ROS, restrict MMP-1 production and promote procollagen type I synthesis. Interestingly, ginsenoside C-Y suppresses UVB-exposed VEGF, and TNF-α secretion, could be related with NFAT signal path. Ginsenoside C-Y has exhibited photoaging effects by increasing TGF-β1 level, fortifying Nrf2 nuclear translocation and restricting AP-1 and MAPK phosphorylation. Assessment of the melanogenic response indicated that ginsenoside C-Y inhibited melanin secretion and tyrosinase activity and decreased melanin content in Melan-a and zebrafish embryos. These results suggest that ginsenoside C-Y can be used as a potential botanical agent to protect premature skin from UVB-induced photodamage and prevent skin hyperpigmentation.

[Chronic leg ulcers in older patients]

Chronic ulcers of the lower extremities are one of the most common medical problems encountered in western societies. The prevalence of leg ulcers is estimated to be 0.5-1.0% of the German population and is clearly associated with age. Therefore, in an aging society chronic leg ulcers are an important health issue with respect to increased morbidity and healthcare costs. The most frequent causes of leg ulcers are chronic venous insufficiency, peripheral arterial occlusive disease and diabetes mellitus. Efficient treatment necessitates an exact diagnosis and a close interdisciplinary collaboration. Affected patients often require instructions regarding self-help and support for competent nursing and prophylaxis. Therapeutic strategies, especially in the geriatric setting, aim to maintain the quality of life through preservation of patient mobility and autonomy.

Melasma: Updates and perspectives

Management of melasma is highly challenging due to inconsistent treatment results and frequent relapses. However, recent studies revealed that melasma may not only be a disease of melanocytes, but also a photoaging skin disorder. Herein, we attempt to validate that melasma is indeed a photoaging disorder by presenting the histopathologic findings of melasma: solar elastosis, altered basement membrane, increased vascularization and increased mast cell count. We also provide some therapeutic implications based on these findings and a discussion on the latest updates and perspectives regarding treatment.

Breaking the frontiers of cosmetology with antimicrobial peptides

Antimicrobial peptides (AMPs) are mostly endogenous, cationic, amphipathic polypeptides, produced by many natural sources. Recently, many biological functions beyond antimicrobial activity have been attributed to AMPs, and some of these have attracted the attention of the cosmetics industry. AMPs have revealed antioxidant, self-renewal and pro-collagen effects, which are desirable in anti-aging cosmetics. Additionally, AMPs may also be customized to act on specific cellular targets. Here, we review the recent literature that highlights the many possibilities presented by AMPs, focusing on the relevance and impact that this potentially novel class of active cosmetic ingredients might have in the near future, creating new market outlooks for the cosmetic industry with these molecules as a viable alternative to conventional cosmetics.

Signatures of photo-aging and intrinsic aging in skin were revealed by transcriptome network analysis

There are various factors that alter physiological characteristics in skin. Elucidating the underlying mechanism of transcriptional alterations by intrinsic and extrinsic factors may lead us to understand the aging process of skin. To identify the transcriptomic changes of the aging skin, we analyzed publicly available RNA sequencing data from Genotype-Tissue Expression (GTEx) project. GTEx provided RNA sequencing data of suprapubic (n=228) and lower leg (n=349) skins, which are photo-protected and photo-damaged. Using differentially expressed gene analysis and weighted gene co-expression network analysis, we characterized transcriptomic changes due to UV exposure and aging. Genes involved in skin development such as epidermal differentiation complex component (SPRR and LCE families), vasculature development (TGFBR1, TGFBR2, TGFBR3, KDR, FGF2, and VEGFC), and matrix metalloproteinase (MMP2, MMP3, MMP8, MMP10, and MMP13) were up-regulated by UV exposure. Also, down-regulated lipid metabolism and mitochondrial biogenesis were observed in photo-damaged skin. Moreover, wound healing process was universally down-regulated in suprapubic and lower leg with aging and further down-regulation of lipid metabolism and up-regulation of vasculature development were found as photo-aging signatures. In this study, dynamic transcriptomic alterations were observed in aged skin. Hence, our findings may help to discover a potential therapeutic target for skin rejuvenation.

Melasma, a photoaging disorder

Melasma is a common hyperpigmentary disorder. The impact on the quality of life of affected individuals is well demonstrated, demanding new therapeutic strategies. However, the treatment of melasma remains highly challenging. Melasma is often considered as the main consequence of female hormone stimulation on a predisposed genetic background. Although these two factors do contribute to this acquired pigmentary disorder, the last decade has revealed several other key players and brought new pieces to the complex puzzle of the pathophysiology of melasma. Here, we summarize the latest evidence on the pathophysiology of melasma, and we suggest that melasma might be a photoaging skin disorder affecting genetically predisposed individuals. Such data must be taken into consideration by clinicians as they could have a profound impact on the treatment and the prevention of melasma.

Protective effects of compounds from Garcinia mangostana L. (mangosteen) against UVB damage in HaCaT cells and hairless mice

Ultraviolet B (UVB) radiation causes alterations in the skin, such as epidermal thickening, wrinkle formation and inflammation. Therefore, preventing UVB-induced skin damage can promote general health among the human population. Garcinia mangostana L. (mangosteen) is a fruit that has become a popular botanical dietary supplement because of its perceived role in promoting overall health. The present study investigated the photoprotective effects of α-, β-, γ-mangostins and gartanin against UVB radiation using the HaCaT immortalized human keratinocyte cell line as an in vitro model and hairless mice as an in vivo model. UVB radiation increased the expression of matrix metalloproteinase (MMP)‑1 and ‑9 and decreased the mRNA expression levels of involucrin, filaggrin and loricrin in HaCaT cells; however, these changes were attenuated by pretreating the cells with α-, β-, γ-mangostins and gartanin. Among these compounds, α-mangostin exhibited the greatest effects in reducing UVB-induced skin wrinkles, inhibited epidermal thickening in hairless mice in vivo. Exposure to UVB radiation increased the expression of MMPs and pro-inflammatory cytokines and activated mitogen-activated protein kinases in hairless mice, but these changes were attenuated by α-mangostin. The authors suggested that α-mangostin exerts anti-wrinkle and anti-aging properties.

AKT and its related molecular feature in aged mice skin

Previous studies suggest that Akt signaling promotes tissue regeneration and decreased Akt activities are found in aged tissues. However, this study finds that the expression and activation levels of Akt in the mice skin increased with age. Additionally, the expression levels of Pten, p16, p21 and p53 also elevated with increased age. Immuno-fluorescence analysis showed that Akt phosphorylation found in the epidermal cells (with increased levels of NF-κB activation) were also found. In vivo inhibition of AKT activity result in reduced NF-κB activation. Our results suggest that increasing Akt/ NF-κB is a crucial mediator of skin aging, which can increase the susceptibility of cell transformation.

Sunlight damage to cellular DNA: Focus on oxidatively generated lesions

The routine and often unavoidable exposure to solar ultraviolet (UV) radiation makes it one of the most significant environmental DNA-damaging agents to which humans are exposed. Sunlight, specifically UVB and UVA, triggers various types of DNA damage. Although sunlight, mainly UVB, is necessary for the production of vitamin D, which is necessary for human health, DNA damage may have several deleterious consequences, such as cell death, mutagenesis, photoaging and cancer. UVA and UVB photons can be directly absorbed not only by DNA, which results in lesions, but also by the chromophores that are present in skin cells. This process leads to the formation of reactive oxygen species, which may indirectly cause DNA damage. Despite many decades of investigation, the discrimination among the consequences of these different types of lesions is not clear. However, human cells have complex systems to avoid the deleterious effects of the reactive species produced by sunlight. These systems include antioxidants, that protect DNA, and mechanisms of DNA damage repair and tolerance. Genetic defects in these mechanisms that have clear harmful effects in the exposed skin are found in several human syndromes. The best known of these is xeroderma pigmentosum (XP), whose patients are defective in the nucleotide excision repair (NER) and translesion synthesis (TLS) pathways. These patients are mainly affected due to UV-induced pyrimidine dimers, but there is growing evidence that XP cells are also defective in the protection against other types of lesions, including oxidized DNA bases. This raises a question regarding the relative roles of the various forms of sunlight-induced DNA damage on skin carcinogenesis and photoaging. Therefore, knowledge of what occurs in XP patients may still bring important contributions to the understanding of the biological impact of sunlight-induced deleterious effects on the skin cells.

Molecular basis of retinol anti-ageing properties in naturally aged human skin in vivo

OBJECTIVE

Retinoic acid has been shown to improve the aged-appearing skin. However, less is known about the anti-ageing effects of retinol (ROL, vitamin A), a precursor of retinoic acid, in aged human skin in vivo. This study aimed to investigate the molecular basis of ROL anti-ageing properties in naturally aged human skin in vivo.

METHODS

Sun-protected buttock skin (76 ± 6 years old, n = 12) was topically treated with 0.4% ROL and its vehicle for 7 days. The effects of topical ROL on skin epidermis and dermis were evaluated by immunohistochemistry, in situ hybridization, Northern analysis, real-time RT-PCR and Western analysis. Collagen fibrils nanoscale structure and surface topology were analysed by atomic force microscopy.

RESULTS

Topical ROL shows remarkable anti-ageing effects through three major types of skin cells: epidermal keratinocytes, dermal endothelial cells and fibroblasts. Topical ROL significantly increased epidermal thickness by stimulating keratinocytes proliferation and upregulation of c-Jun transcription factor. In addition to epidermal changes, topical ROL significantly improved dermal extracellular matrix (ECM) microenvironment; increasing dermal vascularity by stimulating endothelial cells proliferation and ECM production (type I collagen, fibronectin and elastin) by activating dermal fibroblasts. Topical ROL also stimulates TGF-β/CTGF pathway, the major regulator of ECM homeostasis, and thus enriched the deposition of ECM in aged human skin in vivo. 0.4% topical ROL achieved similar results as seen with topical retinoic acid, the biologically active form of ROL, without causing noticeable signs of retinoid side effects.

CONCLUSION

0.4% topical ROL shows remarkable anti-ageing effects through improvement of the homeostasis of epidermis and dermis by stimulating the proliferation of keratinocytes and endothelial cells, and activating dermal fibroblasts. These data provide evidence that 0.4% topical ROL is a promising and safe treatment to improve the naturally aged human skin.

Topical Retinoids: Therapeutic Mechanisms in the Treatment of Photodamaged Skin

Retinoids are a group of substances comprising vitamin A and its natural and synthetic derivatives. Retinoids were first used in dermatology in 1943 by Straumfjord for acne vulgaris. Since that time, retinoids have been utilized in the management and treatment of various skin conditions, including photoaging. Photodamage of the skin occurs as a consequence of cumulative exposure to solar ultraviolet radiation (UVR) and is characterized by deep wrinkles, easy bruising, inelasticity, mottled pigmentation, roughness, and telangiectasias. The mechanism of UVR-induced photodamage is multifactorial. Retinoids have demonstrated efficacy in the treatment of photoaged skin. Indeed, understanding the pathophysiology of photoaging and the molecular mechanism of retinoids can not only provide insight into the effects retinoids can exert in treating photoaging but also provide the rationale for their use in the treatment of other dermatologic diseases.

Phloroglucinol Reduces Photodamage in Hairless Mice via Matrix Metalloproteinase Activity Through MAPK Pathway

We investigated the photoprotective activity of phloroglucinol on ultraviolet B (UVB)-induced deleterious effects in hairless mice in vivo. To assess the photoprotective effect of phloroglucinol, phloroglucinol-treated HR-1 hairless male mice were exposed to UVB irradiation. The inhibitory activity of phloroglucinol on wrinkle formation was determined by analysis of skin replicas, epidermal thickness based on histological examination and collagen damage. Matrix metalloproteinase-1 (MMP-1), matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase (TIMP) mRNA levels were measured by real-time PCR. UVB induced transcription of proinflammatory cytokines, including interleukin-1 beta (IL-1β, IL-6) and IL-8 (IL-8). The protective effects of phloroglucinol on UVB-induced skin photoaging were examined by measuring protein levels of MMPs and mitogen-activated protein (MAP) kinases. The results of these experiments suggest that phloroglucinol has a significant beneficial effect on the barrier function of the skin. In hairless mice, signs of photoaging and photodamage, including coarse wrinkle formation, epidermal thickness and elastic fiber degeneration, were reduced in severity by phloroglucinol application. The phloroglucinol-treated group showed remarkably decreased mRNA levels of MMP-1, MMP-9 and inflammatory cytokines in comparison with those of the UVB-induced group. Oral administration of phloroglucinol attenuated phosphorylation of MAP kinases, including extracellular signal-regulated kinase, c-Jun N-terminal kinase and p38.