Resveratrol Inhibits Particulate Matter-Induced Inflammatory Responses in Human Keratinocytes.

Particulate matter (PM), a major air pollutant, is a complex mixture of solid and liquid particles of various sizes. PM has been demonstrated to cause intracellular inflammation in human keratinocytes, and is associated with various skin disorders, including atopic dermatitis, eczema, and skin aging. Resveratrol is a natural polyphenol with strong antioxidant properties, and its beneficial effects against skin changes due to PM remain elusive. Therefore, in the present study, we investigated the effect of resveratrol on PM-induced skin inflammation and attempted to deduce the molecular mechanisms underlying resveratrol's effects. We found that resveratrol inhibited PM-induced aryl hydrocarbon receptor activation and reactive oxygen species formation in keratinocytes. It also suppressed the subsequent cellular inflammatory response by inhibiting mitogen-activated protein kinase activation. Consequentially, resveratrol reduced PM-induced cyclooxygenase-2/prostaglandin E2 and proinflammatory cytokine expression, including that of matrix metalloproteinase (MMP)-1, MMP-9, and interleukin-8, all of which are known to be central mediators of various inflammatory conditions and aging. In conclusion, resveratrol inhibits the PM-induced inflammatory response in human keratinocytes, and we suggest that resveratrol may have potential for preventing air pollution-related skin problems.

Resveratrol as a Multifunctional Topical Hypopigmenting Agent.

Melanin is produced in melanocytes and stored in melanosomes, after which it is transferred to keratinocytes and, thus, determines skin color. Despite its beneficial sun-protective effects, abnormal accumulation of melanin results in esthetic problems. A range of topical hypopigmenting agents have been evaluated for their use in the treatment of pigmentary disorders with varying degrees of success. Hydroquinone (HQ), which competes with tyrosine, is the main ingredient in topical pharmacological agents. However, frequent occurrence of adverse reactions is an important factor that limits its use. Thus, efforts to discover effective topical hypopigmenting agents with less adverse effects continue. Here, we describe the potential of resveratrol to function as an effective hypopigmenting agent based on its mechanism of action. Resveratrol is not only a direct tyrosinase inhibitor but an indirect inhibitor as well. Additionally, it can affect keratinocytes, which regulate the function of melanocytes. Resveratrol regulates the inflammatory process of keratinocytes and protects them from oxidative damage. In this way, it prevents keratinocyte-induced melanocyte stimulation. Furthermore, it has a rescuing effect on the stemness of interfollicular epidermal cells that can repair signs of photoaging in the melasma, a typical pigmentary skin disorder. Overall, resveratrol is a promising potent hypopigmenting agent.

Molecular Mechanisms of Dermal Aging and Antiaging Approaches.

The dermis is primarily composed of the extracellular matrix (ECM) and fibroblasts. During the aging process, the dermis undergoes significant changes. Collagen, which is a major component of ECM, becomes fragmented and coarsely distributed, and its total amount decreases. This is mainly due to increased activity of matrix metalloproteinases, and impaired transforming growth factor-ß signaling induced by reactive oxygen species generated during aging. The reduction in the amount of collagen hinders the mechanical interaction between fibroblasts and the ECM, and consequently leads to the deterioration of fibroblast function and further decrease in the amount of dermal collagen. Other ECM components, including elastic fibers, glycosaminglycans (GAGs), and proteoglycans (PGs), also change during aging, ultimately leading to a reduction in the amount of functional components. Elastic fibers decrease in intrinsically aged skin, but accumulate abnormally in photoaged skin. The changes in the levels of GAGs and PGs are highly diverse, and previous studies have reported conflicting results. A reduction in the levels of functional dermal components results in the emergence of clinical aging features, such as wrinkles and reduced elasticity. Various antiaging approaches, including topicals, energy-based procedures, and dermal fillers, can restore the molecular features of dermal aging with clinical efficacy. This review summarizes the current understanding of skin aging at the molecular level, and associated treatments, to put some of the new antiaging technology that has emerged in this rapidly expanding field into molecular context.

Avian Collagen Is Useful for the Construction of Skin Equivalents.

As a result of restrictions on animal experimentation, improved skin equivalents (SEs) are needed as alternative test models. This work investigated the effects of avian collagen on the construction of SEs, and to the best of our knowledge is the first study to do so. Hematoxylin and eosin and immunohistochemical staining were used to analyze the SEs. In models containing avian collagen as a dermal equivalent (DE) ingredient, fibroblast proliferation increased by about 60% relative to the control model. Immunohistochemical staining showed that the expression of proliferating cell nuclear antigen (PCNA) and p63 increased in the avian collagen models, while the expression of involucrin, integrin α6, and integrin ß1 remained unchanged. Next, DEs were cryopreserved to allow the easier creation of SEs. Keratinocytes were seeded on thawed DEs, and SEs were constructed. Avian collagen increased the viability of DEs relative to the control. Furthermore, avian collagen increased the expression of PCNA and p63 in keratinocytes on thawed DEs. The results indicate that DEs containing avian collagen can be thawed as needed after cryopreservation. Avian collagen can improve the construction of SEs and be used as part of a dermal kit for SE construction.

Depigmenting Effect of Resveratrol Is Dependent on FOXO3a Activation without SIRT1 Activation.

Resveratrol exhibits not only anti-melanogenic property by inhibiting microphthalmia-associated transcription factor (MITF), but also anti-aging property by activating sirtuin-1 (SIRT1). In this study, the relationship between depigmenting effect of resveratrol and SIRT1/forkhead box O (FOXO) 3a activation and was investigated. Resveratrol suppressed melanogenesis by the downregulation of MITF and tyrosinase via ERK pathway. Results showed that the expression of both SIRT1 and FOXO3a were increased. It is reported that SIRT1 is critical regulator of FOXO-mediated transcription in response to oxidative stress. However in our study, FOXO3a activation appeared earlier than that of SIRT1. Furthermore, the effect of resveratrol on the levels of MITF and tyrosinase was suppressed when melanocytes were pre-treated with SP600125 (JNK inhibitor). However, pre-treatment with SIRT1 inhibitor (EX527, or sirtinol) did not affect the levels of MITF and tyrosinase. Therefore, resveratrol inhibits melanogenesis through the activation of FOXO3a but not by the activation of SIRT1. Although SIRT1 activation by resveratrol is a well-known mechanism of resveratrol-induced antiaging effects, our study showed that not SIRT1 but FOXO3a activation is involved in depigmenting effects of resveratrol.

The Co-Expression Pattern of p63 and HDAC1: A Potential Way to Disclose Stem Cells in Interfollicular Epidermis.

Stem cell markers of interfollicular epidermis (IEF) have not been established thus far. The aim of this study is to suggest a new way to disclose IFE-stem cells by combining the expression of histone deacetylases (HDAC) 1 and p63. Immunohistochemical staining of HDAC1 and p63 was performed in six normal human samples. Moreover, a skin equivalent (SE) model was treated with suberoylanilohydroxamic acid (SAHA, an HDAC inhibitor) to elucidate the role of HDAC1. Finally, rapidly adhering (RA) keratinocytes to a type IV collagen, which have been identified to represent epidermal stem cells, were subjected to Western blot analysis with antibodies against HDAC1. In normal samples, there was a minor subpopulation comprised of p63-positive and HDAC1-negative cells in the basal layers. The proportion of this subpopulation was decreased with age. In the SE model, SAHA treatment increased the epidermal thickness and number of p63-positive cells in a dose dependent manner. After SAHA treatment, the expression of differentiation markers was decreased, while that of basement membrane markers was increased. In a Western blot analysis, HDAC1 was not expressed in RA cells. In conclusion, the combination of p63-positive and HDAC1-negative expressions can be a potential new way for distinguishing epidermal stem cells.

Leucine-rich glioma inactivated 3 is a melanogenic cytokine in human skin.

Recently, we demonstrated that leucine-rich glioma inactivated 3 (LGI3) is expressed in human skin. However, the effects of LGI3 on melanocytes remain unknown. The present study demonstrated that LGI3 can serve to stimulate melanogenesis without affecting cell viability. To determine the effects of LGI3 on melanin synthesis, normal human melanocytes and Mel-Ab cells were treated with recombinant LGI3 and melanin content was measured. Our results showed that LGI3 promoted melanin synthesis in both cell types. Moreover, upregulation of microphthalmia-associated transcription factor (MITF) and tyrosinase was observed at both the mRNA and protein levels via RT-PCR and Western blotting, respectively. Furthermore, immunohistochemical staining showed that the expression of LGI3 increased in the basal layer of melasma skin samples, whereas it decreased slightly in vitiligo samples. These results suggest that LGI3 may play a role as a melanogenic cytokine in human skin.

Hypopigmentary effects of ethyl P-methoxycinnamate isolated from Kaempferia galanga.

We isolated crystals from the chloroform fraction of an ethanol extract of Kaempferia galanga and identified it as ethyl p-methoxycinnamate through nuclear magnetic resonance analysis. In the present study, we found that ethyl p-methoxycinnamate significantly decreased melanin synthesis in B16F10 murine melanoma cells stimulated with α-melanocyte stimulating hormone (α-MSH). In a cell-free system, however, ethyl p-methoxycinnamate did not directly inhibit tyrosinase, the rate-limiting enzyme of melanogenesis. Instead, it inhibited tyrosinase activity in B16F10 cells in a dose-dependent manner. Furthermore, Western blot analysis showed that ethyl p-methoxycinnamate decreased microphthalmia-associated transcription factor and tyrosinase levels in α-MSH-stimulated B16F10 cells. These results indicate that the pigment-inhibitory effect of ethyl p-methoxycinnamate results from downregulation of tyrosinase. Ethyl p-methoxycinnamate isolated from K. galanga could be developed as a skin whitening agent to treat hyperpigmentary disorders.

Fucoidan promotes the reconstruction of skin equivalents.

In this study we investigated the effects of fucoidan on the proliferation of fibroblasts and the reconstruction of a skin equivalent (SE). Fucoidan significantly stimulated the proliferation of CCD-25Sk human fibroblasts and Western blot analysis demonstrated that fucoidan markedly increased the expression of cyclin D1 and decreased the expression of p27. Fucoidan was used to reconstruct SE. Immunohistochemical staining showed that the addition of fucoidan to dermal equivalents increased expression of proliferating cell nuclear antigen (PCNA) and p63. In addition, expression of α6-integrin was significantly increased by fucoidan, whereas expression of ß1-integrin, type 1 collagen, elastin, fibronectin did not markedly change. These results suggest that fucoidan has positive effects on epidermal reconstruction and will therefore be beneficial in the reconstruction of SE.

Artificial intelligence-based prescription of personalized scalp cosmetics improved the scalp condition: efficacy results from 100 participants.

Background: Scalp-related symptoms such as dandruff and itching are common with diverse underlying etiologies. We previously proposed a novel classification and scoring system for scalp conditions, called the scalp photographic index (SPI); it grades five scalp features using trichoscopic images with good reliability. However, it requires trained evaluators.Aim: To develop artificial intelligence (AI) algorithms for assessment of scalp conditions and to assess the feasibility of AI-based recommendations on personalized scalp cosmetics.Methods: Using EfficientNet, convolutional neural network (CNN) models (SPI-AI) ofeach scalp feature were established. 101,027 magnified scalp images graded according to the SPI scoring were used for training, validation, and testing the model Adults with scalp discomfort were prescribed shampoos and scalp serums personalized according to their SPI-AI-defined scalp types. Using the SPI, the scalp conditions were evaluated at baseline and at weeks 4, 8, and 12 of treatment.Results: The accuracies of the SPI-AI for dryness, oiliness, erythema, folliculitis, and dandruff were 91.3%, 90.5%, 89.6%, 87.3%, and 95.2%, respectively. Overall, 100 individuals completed the 4-week study; 43 of these participated in an extension study until week 12. The total SPI score decreased from 32.70 ± 7.40 at baseline to 15.97 ± 4.68 at week 4 (p < 0.001). The efficacy was maintained throughout 12 weeks.Conclusions: SPI-AI accurately assessed the scalp condition. AI-based prescription of tailored scalp cosmetics could significantly improve scalp health.

Retinoic acid inhibits adipogenesis via activation of Wnt signaling pathway in 3T3-L1 preadipocytes.

Although retinoic acid (RA) is well known to inhibit the differentiation of 3T3-L1 cells into adipocytes both in vivo and in vitro, its molecular mechanism is not fully understood. In this report, we investigate the inhibitory mechanism of adipocyte differentiation by RA in 3T3-L1 cells. Because both RA and Wnt are known to inhibit adipogenesis at a common step involving the inhibition of PPAR-γ expression, we focused on the crosstalk between these two signaling pathways. We found that RA treatment resulted in a dramatic inhibition of adipogenesis, especially at an early phase of differentiation, and led to increased ß-catenin protein expression. Moreover, RA enhances the transcriptional activity of ß-catenin as well as Wnt gene expression during adipogenesis. Taken together, the present study demonstrated that Wnt/ß-catenin signaling may be associated with the RA-induced suppression of adipogenesis and may cooperatively inhibit adipocyte differentiation.

Ceramide PC102 inhibits melanin synthesis via proteasomal degradation of microphthalmia-associated transcription factor and tyrosinase.

A few types of ceramide are reported to decrease melanin synthesis. In the present study, we examined the effects of an artificial ceramide analog, PC102, on melanogenesis using a spontaneously immortalized melanocyte cell line (Mel-Ab). PC102 is currently used as a moisturizing additive in a variety of cosmetics. Our data showed that PC102 inhibited melanin production and tyrosinase activity in a dose-dependent manner, but did not directly affect tyrosinase activity. Microphthalmia-associated transcription factor (MITF), tyrosinase, and ß-catenin protein levels decreased after 48 h of PC102 treatment. In contrast, PC102 did not decrease MITF, tyrosinase, and ß-catenin mRNA levels. Therefore, we investigated whether the decrease in MITF and tyrosinase by PC102 is due to proteasomal degradation. MG132, a proteasomal inhibitor, completely abolished tyrosinase downregulation due to PC102 and partially reduced the downregulation of MITF and ß-catenin due to PC102. Moreover, MG132 abrogated the inhibition of melanin synthesis by PC102. Taken together, our data suggest that PC102 may inhibit melanin synthesis through MITF and tyrosinase degradation.

Synthesis and dual biological effects of hydroxycinnamoyl phenylalanyl/prolyl hydroxamic acid derivatives as tyrosinase inhibitor and antioxidant.

We previously reported that caffeoyl-amino acidyl-hydroxamic acid (CA-Xaa-NHOH) acted as both a good antioxidant and tyrosinase inhibitor, in particular when caffeic acid was conjugated with proline or amino acids having aromatic ring like phenylalanine. Here, various hydroxycinnamic acid (HCA) derivatives were further conjugated with phenylalanyl hydroxamic acid and prolyl hydroxamic acid (HCA-Phe-NHOH and HCA-Pro-NHOH) to study the structure and activity relationship as both antioxidants and tyrosinase inhibitors. When their biological activities were evaluated, all HCA-Phe-NHOH and HCA-Pro-NHOH exhibited enhanced antioxidant activity compared to HCA alone. Moreover, derivatives of caffeic acid, ferulic acid, and sinapic acid inhibited lipid peroxidation more efficiently than vitamin E analogue (Trolox). In addition, derivatives of caffeic acid and sinapic acid efficiently inhibited tyrosinase activity and reduced melanin content in melanocytes Mel-Ab cell.

Wearable and Wavelength-Tunable Near-Infrared Organic Light-Emitting Diodes for Biomedical Applications.

Near-infrared organic light-emitting diodes (NIR OLEDs) have significant potential for wearable phototherapeutic applications because of the unique properties of the OLEDs, including their free-form electronics and the excellent biomedical effects of NIR emission. In spite of their tremendous promise, given that the majority of NIR OLEDs in previous research have relied on the utilization of an intrinsically brittle indium tin oxide (ITO) electrode, their practicality in the field of wearable electronics is inherently constrained. Here, we report wearable and wavelength-tunable NIR OLEDs that employ a high-performance NIR emitter and an innovative architecture by replacing the ITO with a silver (Ag) electrode. The NIR OLEDs permit wavelength tuning of emissions from 700 to 800 nm and afford stable operation even under repeated bending conditions. The NIR OLEDs provide a lowered device temperature of 37.5 °C even during continuous operation under several emission intensities. In vitro experiments were performed with freshly fabricated NIR OLEDs. The outcomes were evaluated against experimental results performed using the same procedure utilizing blue, green, and red OLEDs. When exposed to NIR light irradiation, the promoting effect of cell proliferation surpassed the proliferative responses observed under the influence of visible light irradiation. The proliferation effect of human hair follicle dermal papilla cells is clearly related to the irradiation wavelength and time, thus underscoring the potential of wavelength-tunable NIR OLEDs for efficacious phototherapy. This work will open novel avenues for wearable NIR OLEDs in the field of biomedical application.

Stem cell recovering effect of copper-free GHK in skin.

The peptide Gly-His-Lys (GHK) is a naturally occurring copper(II)-chelating motifs in human serum and cerebrospinal fluid. In industry, GHK (with or without copper) is used to make hair and skin care products. Copper-GHK plays a physiological role in the process of wound healing and tissue repair by stimulating collagen synthesis in fibroblasts. We also reported that copper-GHK promotes the survival of basal stem cells in the skin. However, the effects of copper-free GHK (GHK) have not been investigated well. In this study, the effects of GHK were studied using cultured normal human keratinocytes and skin equivalent (SE) models. In monolayer cultured keratinocytes, GHK increased the proliferation of keratinocytes. When GHK was added during the culture of SE models, the basal cells became more cuboidal than control model. In addition, there was linear and intense staining of α6 and ß1 integrin along the basement membrane. The number of p63 and proliferating cell nuclear antigen positive cells was also significantly increased in GHK-treated SEs than in control SEs. Western blot and slide culture experiment showed that GHK increased the expression of integrin by keratinocytes. All these results showed that GHK increased the stemness and proliferative potential of epidermal basal cells, which is associated with increased expression of integrin. In conclusion, copper-free GHK showed similar effects with copper-GHK. Thus, it can be said that copper-free GHK can be used in industry to obtain the effects of copper-GHK in vivo. Further study is necessary to explore the relationship between copper-free GHK and copper-GHK.

Cell proliferation effect of deep-penetrating microcavity tandem NIR OLEDs with therapeutic trend analysis.

Long wavelengths that can deeply penetrate into human skin are required to maximize therapeutic effects. Hence, various studies on near-infrared organic light-emitting diodes (NIR OLEDs) have been conducted, and they have been applied in numerous fields. This paper presents a microcavity tandem NIR OLED with narrow full-width half-maximum (FWHM) (34 nm), high radiant emittance (> 5 mW/cm2) and external quantum efficiency (EQE) (19.17%). Only a few papers have reported on biomedical applications using the entire wavelength range of the visible and NIR regions. In particular, no biomedical application studies have been reported in the full wavelength region using OLEDs. Therefore, it is worth researching the therapeutic effects of using OLED, a next-generation light source, and analyzing trends for cell proliferation effects. Cell proliferation effects were observed in certain wavelength regions when B, G, R, and NIR OLEDs were used to irradiate human fibroblasts. The results of an in-vitro experiment indicated that the overall tendency of wavelengths is similar to that of the cytochrome c oxidase absorption spectrum of human fibroblasts. This is the first paper to report trends in the cell proliferation effects in all wavelength regions using OLEDs.

Dual effects of caffeoyl-amino acidyl-hydroxamic acid as an antioxidant and depigmenting agent.

Anti-aging and depigmentation have both been an important subject of study for skin disease and the cosmetic industry. Caffeic acid (CA) has shown synergistically enhanced antioxidant activity when conjugated with amino acids. Hydroxamic acid (NHOH) is a well-known metal chelator, potentially having both tyrosinase inhibitory activity and free radical scavenging activity. We prepared caffeoyl-amino acidyl-hydroxamic acid (CA-Xaa-NHOH) and found that caffeoyl-prolyl-hydroxamic acid (CA-Pro-NHOH) contained excellent antioxidant activity and tyrosinase inhibitory activity by various bioassay systems. Also, CA-Pro-NHOH showed mild melanogenesis inhibitory activity in Mel-Ab cells.

Kojic acid-amino acid amide metal complexes and their melanogenesis inhibitory activities.

Tyrosinase plays a critical role in the early stages of the melanin synthetic pathway by catalyzing the oxidation of the substrate. Therefore, tyrosinase inhibitors have been intensively studied in both cosmetic and food industries to develop hypopigmentary agents and prevent enzymatic browning in food. Previously, we reported that kojic acid-amino acid amide (KA-AA-NH(2)) showed enhanced tyrosinase inhibitory activity compared with kojic acid alone, but this was not observed in a cell test because of poor cell permeability. To enhance cell permeability, we prepared copper and zinc complexes of KA-AA-NH(2) and characterized them using FT-IR spectroscopy, ESI-MS spectrometry, and inductively coupled plasma analysis. We then showed that KA-AA-NH(2) copper complexes exhibited melanogenesis inhibitory activity in Mel-Ab cells.

Rapid healing and reduced erythema after ablative fractional carbon dioxide laser resurfacing combined with the application of autologous platelet-rich plasma.

BACKGROUND: Fractional carbon dioxide laser resurfacing (FxCR) has shown considerable efficacy in reducing wrinkles, although complications such as scarring and prolonged erythema are more common and down-time is longer than with nonablative laser treatment. Platelet-rich plasma (PRP), a high concentration of platelets in a small volume of plasma, is known to enhance tissue healing. OBJECTIVE: To evaluate the benefits of PRP in the wound healing process after FxCR. MATERIALS AND METHODS: Twenty-five subjects were treated with FxCR on the bilateral inner arms. PRP was prepared from 10 mL of whole blood and applied on a randomly allocated side, with normal saline being used as the contralateral control. Transepidermal water loss (TEWL) and skin color were measured on both sides. Skin biopsies were also taken from five subjects on day 28. RESULTS: Significantly faster recovery of TEWL was seen on the PRP-treated side. The erythema index and melanin index on the PRP-treated side were lower than on the control side. Biopsy specimens from the PRP-treated side showed thicker collagen bundles than those from the control side. CONCLUSION: Application of autologous PRP is an effective method for enhancing wound healing and reducing transient adverse effects after FxCR treatment.

Enhanced cell permeability of kojic acid-phenylalanine amide with metal complex.

Kojic acid-phenylalanine amide (KA-F-NH(2)), which showed an excellent tyrosinase inhibitory activity, did not inhibit melanogenesis in melanocyte due to its low cell permeability. To enhance its cell permeability by increasing lipophilicity, we prepared metal coordination compounds of KA-F-NH(2) and characterized them by FT-IR and ICP analysis. The metal complex of KA-F-NH(2) inhibited mushroom tyrosinase activity as much as KA-F-NH(2) and reduced melanin contents in melanocyte efficiently.