Development of an improved inhibitor of Lats kinases to promote regeneration of mammalian organs.

The Hippo signaling pathway acts as a brake on regeneration in many tissues. This cascade of kinases culminates in the phosphorylation of the transcriptional cofactors Yap and Taz, whose concentration in the nucleus consequently remains low. Various types of cellular signals can reduce phosphorylation, however, resulting in the accumulation of Yap and Taz in the nucleus and subsequently in mitosis. We earlier identified a small molecule, TRULI, that blocks the final kinases in the pathway, Lats1 and Lats2, and thus elicits proliferation of several cell types that are ordinarily postmitotic and aids regeneration in mammals. In the present study, we present the results of chemical modification of the original compound and demonstrate that a derivative, TDI-011536, is an effective blocker of Lats kinases in vitro at nanomolar concentrations. The compound fosters extensive proliferation in retinal organoids derived from human induced pluripotent stem cells. Intraperitoneal administration of the substance to mice suppresses Yap phosphorylation for several hours and induces transcriptional activation of Yap target genes in the heart, liver, and skin. Moreover, the compound initiates the proliferation of cardiomyocytes in adult mice following cardiac cryolesions. After further chemical refinement, related compounds might prove useful in protective and regenerative therapies.

Understanding the causes of skincare product pilling.

BACKGROUND: Skincare and makeup "pilling" is an unsightly and undesirable phenomenon whereby skincare such as moisturizers or foundation ball up to form flakes on the skin. To date, the causes of skincare product pilling have not been studied. This study aimed to examine the relationship between skin physiology and pilling potential of sunscreen and foundation (the two products most reported by consumers to cause pilling). This study also examined the effects of product application methods on pilling. MATERIALS AND METHODS: 528 female volunteers from Guangzhou, China, aged between 20 and 49 years, underwent various clinical skin assessments, followed by three steps of product layering. Pilling was assessed after each product application step. RESULTS: 217 volunteers (41%) experienced pilling. The majority of pilling (n = 655 events) occurred following sunscreen application, while only a few pilling events (n = 35) occurred with foundation. Foundation improved pilling caused by sunscreen in 98.9% of cases. Volunteers experiencing pilling with both sunscreen and foundation had significantly lower facial skin hydration and oiliness, higher pH, and smoother skin texture (P < 0.05). Two application methods, rubbing of products in circular and linear motions, yielded the highest numbers of pilling events. CONCLUSION: This study has provided the first insights into the causes of pilling. Sunscreen is a promoter of pilling, while foundation may resolve sunscreen-induced pilling in many cases. Skin physiology, particularly drier, smoother skin with higher pH, and product application methods are likely contributing factors to this undesirable phenomenon.

Clinical efficacy of a multilamellar cream on skin physiology and microbiome in an epidermal stress model: A controlled double-blinded study.

INTRODUCTION: Stratum corneum (SC) is essential for skin barrier function, mitigating water loss and shielding against potentially harmful substances and allergens. The SC's lipid matrix, arranged in a lamellar structure, is integral to its protective role. Our study explores the restoration effects of a multilamellar cream with an acidic pH compared to a basic placebo cream on skin physiology and its interaction with the skin microbiome after stress induction via tape stripping (TS). MATERIALS AND METHODS: In this double-blind study, 14 healthy participants aged 21-58 years were assessed pre- and post-tape stripping, followed by a 14 days application of a multilamellar test cream and a placebo cream with evaluations on days 7, 14 and 17 for sustained effects. Skin physiology was analysed in terms of epidermal barrier function, SC hydration and surface pH. The microbiome was analysed by 16S rRNA amplicon sequencing the 16S rRNA gene using Illumina MiSeq, with subsequent species identification. RESULTS: Our study showed significant improvements in skin barrier repair and SC hydration with verum, particularly after 14 days of application, while both creams initially enhanced stratum corneum hydration. No significant changes in surface-pH were detected. The skin microbiome analysis revealed that TS slightly decreased alpha diversity, a trend that verum significantly reversed, enhancing diversity beyond baseline levels after 14 days. Overall, while both creams contributed to a broader microbial phyla diversity over time, no significant changes in the abundance of specific genera or species were noted between treatments. DISCUSSION AND CONCLUSION: Our study delineates the efficacy of a pH-optimized multilamellar cream in enhancing epidermal barrier recovery and SC hydration post-sequential TS, in contrast to an unstructured basic placebo. Verum cream significantly improved skin barrier function and SC hydration at day 14, with sustained effects evident beyond the treatment period. Furthermore, the multilamellar formulation facilitated the restitution of cutaneous microbiome diversity, a key indicator of healthy skin ecology, underscoring the symbiotic relationship between barrier integrity and microbial composition. These findings underscore the importance of multilamellar emollient structures in dermatological therapeutics, with potential implications for the design of advanced skincare interventions that holistically support cutaneous resilience and homeostasis.

INTRODUCTION: La couche cornée (stratum corneum, SC) est essentielle pour la fonction de barrière cutanée, atténuant la perte d'eau et protégeant contre les substances et allergènes potentiellement nocifs. Disposée selon une structure lamellaire, la matrice lipidique de la SC est constitutive de son rôle protecteur. Notre étude explore les effets de restauration d'une crème multilamellaire à pH acide par rapport à une crème placebo de base sur la physiologie de la peau et son interaction avec le microbiome de la peau après induction de stress via un test tape stripping (TS). MATÉRIELS ET MÉTHODES: Dans cette étude en double aveugle, 14 participants en bonne santé âgés de 21 à 58 ans ont été évalués avant et après tape stipping, puis ont procédé à l'application pendant 14 jours d'une crème test multilamellaire et d'une crème placebo avec des évaluations aux jours 7, 14 et 17 pour les effets durables. La physiologie de la peau a été analysée en termes de fonction de la barrière épidermique, d'hydratation SC et de pH de surface. Le microbiome a été analysé par séquençage de l'amplicon de l'ARNr 16S sur le gène de l'ARNr 16S à l'aide d'Illumina MiSeq, avec identification ultérieure des espèces. RÉSULTATS: Notre étude a montré des améliorations significatives de la réparation de la barrière cutanée et de l'hydratation SC avec le traitement actif, en particulier après 14 jours d'application, tandis que les deux crèmes avaient initialement amélioré l'hydratation de la couche cornée. Aucun changement significatif du pH de surface n'a été détecté. L'analyse du microbiome cutané a révélé que le TS diminuait légèrement la diversité alpha, une tendance qui s'est significativement inversée avec le traitement actif : une amélioration de la diversité au­delà des taux initiaux était observée après 14 jours. Dans l'ensemble, bien que les deux crèmes aient contribué à une plus grande diversité des phyla microbiennes au fil du temps, aucune variation significative dans l'abondance de genres ou d'espèces spécifiques n'a été observée entre les traitements. DISCUSSION ET CONCLUSION: Notre étude délimite l'efficacité d'une crème multilamellaire à pH optimisé pour améliorer la réparation de la barrière épidermique et l'hydratation SC après un TS séquentiel, contrairement à un placebo basique non structuré. La crème contenant le traitement actif a significativement amélioré la fonction de barrière cutanée et l'hydratation SC au jour 14, avec des effets durables évidents au­delà de la période de traitement. En outre, la formulation multilamellaire a facilité la restitution de la diversité du microbiome cutané, un indicateur clé d'une écologie de peau en bonne santé, soulignant la relation symbiotique entre l'intégrité de la barrière et la composition microbienne. Ces résultats soulignent l'importance des structures émollientes multilamellaires dans les traitements dermatologiques, avec des implications potentielles pour la conception d'interventions cutanées avancées qui soutiennent de manière holistique la résilience cutanée et l'homéostasie.

Chitosan/Alginate Hydrogel Dressing Loaded FGF/VE-Cadherin to Accelerate Full-Thickness Skin Regeneration and More Normal Skin Repairs.

The process of full-thickness skin regeneration is complex and has many parameters involved, which makes it difficult to use a single dressing to meet the various requirements of the complete regeneration at the same time. Therefore, developing hydrogel dressings with multifunction, including tunable rheological properties and aperture, hemostatic, antibacterial and super cytocompatibility, is a desirable candidate in wound healing. In this study, a series of complex hydrogels were developed via the hydrogen bond and covalent bond between chitosan (CS) and alginate (SA). These hydrogels exhibited suitable pore size and tunable rheological properties for cell adhesion. Chitosan endowed hemostatic, antibacterial properties and great cytocompatibility and thus solved two primary problems in the early stage of the wound healing process. Moreover, the sustained cytocompatibility of the hydrogels was further investigated after adding FGF and VE-cadherin via the co-culture of L929 and EC for 12 days. The confocal 3D fluorescent images showed that the cells were spherical and tended to form multicellular spheroids, which distributed in about 40-60 µm thick hydrogels. Furthermore, the hydrogel dressings significantly accelerate defected skin turn to normal skin with proper epithelial thickness and new blood vessels and hair follicles through the histological analysis of in vivo wound healing. The findings mentioned above demonstrated that the CS/SA hydrogels with growth factors have great potential as multifunctional hydrogel dressings for full-thickness skin regeneration incorporated with hemostatic, antibacterial, sustained cytocompatibility for 3D cell culture and normal skin repairing.

A Mixture of Topical Forms of Polydeoxyribonucleotide, Vitamin C, and Niacinamide Attenuated Skin Pigmentation and Increased Skin Elasticity by Modulating Nuclear Factor Erythroid 2-like 2.

It is well-known that increased oxidative stress caused by ultraviolet B (UV-B) radiation induces melanogenesis and activates metalloproteinases (MMPs), which degrade collagen and elastin fibers, leading to decreased skin elasticity. Various antioxidant agents, such as vitamin C and niacinamide, have been evaluated for use as treatments for photoaging or skin pigmentation. In this study, we evaluated the ability of a topical liquid formula of polydeoxyribonucleotide (PDRN), vitamin C, and niacinamide (PVN) delivered via a microneedling therapy system (MTS) to attenuate photoaging and pigmentation by increasing nuclear factor erythroid 2-like 2 (NRF2)/heme oxygenase-1 (HO-1) and decreasing MMP expression in a UV-B-radiated animal model. The effects of the PVN were compared with those of individual PDRN and hydroquinone (HQ) compounds. The expression of NRF2/HO-1 significantly increased in response to HQ, PDRN, and PVN in UV-B-radiated animal skin. The activity of nicotinamide adenine dinucleotide phosphate hydrogen oxidase decreased in response to HQ, PDRN, and PVN, and the superoxide dismutase activity increased. The expression of tumor protein p53 and microphthalmia-associated transcription factor and tyrosinase activity decreased in response to HQ, PDRN, and PVN, and this decrease was accompanied by decreased melanin content in the skin. The expression of nuclear factor kappa-light-chain enhancer of activated B cells and MMP2/3/9 decreased in response to HQ, PDRN, and PVN in UV-B-radiated skin. However, the expression of collagen type I α1 chain and the amount of collagen fibers that were evaluated by Masson's trichrome staining increased in response to HQ, PDRN, and PVN. The contents of elastin fibers, fibrillin 1/2 and fibulin 5 increased in response to HQ, PDRN, and PVN. In conclusion, PVN delivered via MTS led to decreased melanogenesis and destruction of collagen and elastin fibers by MMPs, and, thus, PVN decreased skin pigmentation and increased skin elasticity.

Topical application with conjugated linoleic acid ameliorates 2, 4-dinitrofluorobenzene-induced atopic dermatitis-like lesions in BALB/c mice.

Atopic dermatitis (AD) is a multifactorial chronic inflammatory skin disease characterized by skin barrier dysfunction, eczematous lesions, pruritus, and abnormal immune responses. In this study, we assessed the therapeutic effect of topical applied conjugated linoleic acid (CLA) on a murine AD model that was developed by repetitive applications of 2, 4-dinitrofluorobenzene (DNFB). 2% or 5% CLA could markedly ameliorate AD-like skin lesions, scratching behaviour and skin inflammation as evidenced by the reduced inflammatory blood cells, IgE and Th2-related cytokine levels, and the infiltration of mast cells and inflammatory cells to the dermal tissues. Moreover, topical application with CLA modulated skin barrier repair including maintaining a balanced skin pH and increasing skin hydration, partially mediated by upregulating skin barrier-related protein, filaggrin (FLG). In addition, topical CLA significantly dose-dependently inhibited pro-inflammatory cytokines including interleukin (IL)-6, IL-1ß, tumour necrosis factor (TNF)-α and pro-inflammatory enzyme expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in inflamed mice skin. Its anti-inflammatory effect was associated with the inhibition of DNFB-stimulated IκBα and NF-κB p65 phosphorylation in mouse skin. Taken together, our results suggest that locally applied CLA exerts potentially protective effects against AD lesional skin at least in part, due to regulation of skin barrier function and inflammatory response.

Vitamin E in Atopic Dermatitis: From Preclinical to Clinical Studies.

BACKGROUND: Oxidative stress and inflammation are some of the proposed mechanisms involved in the pathogenesis of atopic dermatitis (AD). Current pharmacotherapeutic approaches are effective yet they are not without adverse effects. Vitamin E has great potential as an adjunctive treatment for AD owing to its antioxidant and anti-inflammatory bioactivities. SUMMARY: This review article summarizes the current available evidence from cellular, animal and clinical studies on the relationship between vitamin E and AD. The future prospects of vitamin E are also discussed. Vitamin E in practice does not show any toxicity to humans within a range of reasonable dosage. Albeit rarely, vitamin E as a contact allergen should be considered. Collectively, this review envisaged vitamin E as an adjunctive treatment for AD patients. Future research on the distinct effects of different vitamin E isoforms as well as their delivery system in skin disorders is needed.

Functional Dissection of CD26 and Its Pharmacological Inhibition by Sitagliptin During Skin Wound Healing.

BACKGROUND Skin fibroblasts are primary mediators underlying wound healing and therapeutic targets in scar prevention and treatment. CD26 is a molecular marker to distinguish fibroblast subpopulations and plays an important role in modulating the biological behaviors of dermal fibroblasts and influencing skin wound repair. Therapeutic targeting of specific fibroblast subsets is expected to reduce skin scar formation more efficiently. MATERIAL AND METHODS Skin burn and excisional wound healing models were surgically established in mice. The expression patterns of CD26 during wound healing were determined by immunohistochemical staining, real-time RT-PCR, and western blot assays. Normal fibroblasts from intact skin (NFs) and fibroblasts in wounds (WFs) were isolated and sorted by fluorescence-activated cell sorting (FACS) into 4 subgroups - CD26⁺ NFs, CD26⁻ NFs, CD26⁺ WFs, and CD26⁻ WFs - for comparisons of their capacities of proliferation, migration, and collagen synthesis. Pharmacological inhibition of CD26 by sitagliptin in skin fibroblasts and during wound healing were further assessed both in vitro and in vivo. RESULTS Increased CD26 expression was observed during skin wound healing in both models. The CD26⁺ fibroblasts isolated from wounds had significantly stronger abilities to proliferate, migrate, and synthesize collagen than other fibroblast subsets. Sitagliptin treatment potently diminished CD26 expression, impaired the proliferation, migration, and collagen synthesis of fibroblasts in vitro, and diminished scar formation in vivo. CONCLUSIONS Our data reveal that CD26 is functionally involved in skin wound healing by regulating cell proliferation, migration, and collagen synthesis in fibroblasts. Pharmacological inhibition of CD26 by sitagliptin might be a viable strategy to reduce skin scar formation.

Nanomaterials in Skin Regeneration and Rejuvenation.

Skin is the external part of the human body; thus, it is exposed to outer stimuli leading to injuries and damage, due to being the tissue mostly affected by wounds and aging that compromise its protective function. The recent extension of the average lifespan raises the interest in products capable of counteracting skin related health conditions. However, the skin barrier is not easy to permeate and could be influenced by different factors. In the last decades an innovative pharmacotherapeutic approach has been possible thanks to the advent of nanomedicine. Nanodevices can represent an appropriate formulation to enhance the passive penetration, modulate drug solubility and increase the thermodynamic activity of drugs. Here, we summarize the recent nanotechnological approaches to maintain and replace skin homeostasis, with particular attention to nanomaterials applications on wound healing, regeneration and rejuvenation of skin tissue. The different nanomaterials as nanofibers, hydrogels, nanosuspensions, and nanoparticles are described and in particular we highlight their main chemical features that are useful in drug delivery and tissue regeneration.

Ex Vivo Live Full-Thickness Porcine Skin Model as a Versatile In Vitro Testing Method for Skin Barrier Research.

Since the European Union (EU) announced their animal testing ban in 2013, all animal experiments related to cosmetics have been prohibited, creating a demand for alternatives to animal experiments for skin studies. Here, we investigated whether an ex vivo live porcine skin model can be employed to study the safety and skin barrier-improving effects of hydroxyacids widely used in cosmetics for keratolytic peels. Glycolic acid (1-10%), salicylic acid (0.2-2%), and lactobionic acid (1.2-12%) were used as representative substances for α-hydroxyacid (AHA), ß-hydroxyacid (BHA), and polyhydroxyacid (PHA), respectively. When hydroxyacids were applied at high concentrations on the porcine skin every other day for 6 days, tissue viability was reduced to 50-80%, suggesting that the toxicity of cosmetic ingredients can be evaluated with this model. Based on tissue viability, the treatment scheme was changed to a single exposure for 20 min. The protective effects of a single exposure of hydroxyacids on skin barrier function were evaluated by examining rhodamine permeability and epidermal structural components of barrier function using immunohistochemistry (IHC) and immunofluorescence (IF) staining. Lactobionic acid (PHAs) improved skin barrier function most compared to other AHAs and BHAs. Most importantly, trans-epidermal water loss (TEWL), an important functional marker of skin barrier function, could be measured with this model, which confirmed the significant skin barrier-protective effects of PHAs. Collectively, we demonstrated that the ex vivo live full-thickness porcine skin model can be an excellent alternative to animal experiments for skin studies on the safety and efficacy of cosmetic ingredients.

Comparative Morphological Study of the Formation of Reparative Regenerate during Skin Wound Healing in Rats under the Effect of Drugs and Bone Marrow.

We studied the formation of the reparative regenerate of the skin wound in rats under the effect of drug products based on keratan and secretome of bone marrow mesenchymal stem cells (MSC), as well as bone marrow cells (native and exposed to laser radiation with a wavelength of 1.56 µm). Due to the biological affinity for the dermal tissue, keratan preparations being applied to the skin stimulate regeneration of the wound defect. This substance in the form of a gel is characterized by high diffusion capacity, penetrates into the deeper layers of the dermis, and promotes the growth of the granulation tissue. Application of an ointment prepared on the basis of MSC secretome promotes quick transition of the healing process from the inflammatory to the regenerative stage. Thus, bone marrow cells were successfully used for skin wound healing. The results of the use of bone marrow cells for the healing of skin wounds were successful; bone marrow exposed to laser radiation demonstrated high efficiency in promoting reparative processes.

Topical doxycycline monohydrate hydrogel 1% targeting proteases/PAR2 pathway is a novel therapeutic for atopic dermatitis.

Atopic Dermatitis (AD) is characterized by skin barrier disruption and an aberrant immune response. Doxycycline is tetracycline antibiotics broadly used systemically to treat inflammatory dermatologic conditions. Several studies have shown doxycycline has anti-inflammatory and pro-healing properties, mainly by blocking tissue proteolytic activity. It is our hypothesis that daily application of a novel doxycycline topical formulation in AD subjects will reduce severity of the disease, by blocking cutaneous proteases activity and restoring skin barrier function and inflammation. To test this hypothesis, we performed a proof of concept, open-label clinical study. Subjects enrolled in the study (n = 15) applied NanoDOX® Hydrogel 1% daily for 4 weeks on a chosen eczematous area. Investigational drug was well tolerated, and no local or systemic adverse events due to investigational drug were reported. Notably, a significant clinical improvement was observed based on a modified Eczema Area & Severity Index (EASI) score of the treated area from start of treatment to 14 and 28 days post-treatment (P < .001). A significant improvement of pruritus was also observed (P = .02). This proof of concept clinical trial is first to explore the impact of a non-systemic doxycycline treatment on AD patients. Our results provide evidence to investigate novel AD treatment strategies targeting cutaneous proteases activity.

Biological barriers, and the influence of protein binding on the passage of drugs across them.

Drug-protein binding plays a key role in determining the pharmacokinetics of a drug. The distribution and protein binding ability of a drug changes over a lifetime, and are important considerations during pregnancy and lactation. Although proteins are a significant fraction in plasma composition, they also exist beyond the bloodstream and bind with drugs in the skin, tissues or organs. Protein binding influences the bioavailability and distribution of active compounds, and is a limiting factor in the passage of drugs across biological membranes and barriers: drugs are often unable to cross membranes mainly due to the high molecular mass of the drug-protein complex, thus resulting in the accumulation of the active compounds and a significant reduction of their pharmacological activity. This review describes the consequences of drug-protein binding on drug transport across physiological barriers, whose role is to allow the passage of essential substances-such as nutrients or oxygen, but not of xenobiotics. The placental barrier regulates passage of xenobiotics into a fetus and protects the unborn organism. The blood-brain barrier is the most important barrier in the entire organism and the skin separates the human body from the environment.

Optimal Support of Wound Healing: New Insights.

BACKGROUND: The ultimate goal of wound healing following minor injury is to form a tissue regenerate that has functionality and visual appearance as close to the original skin as possible. The body's physiological response to any wound is traditionally characterised by three distinct steps: inflammation, proliferation and remodelling. SUMMARY: New insights suggest that the three phases overlap (and even occur in parallel) in both time and space in the wound, necessitating a clinical approach that targets each stage simultaneously to ensure rapid repair and wound closure without further complications. Ingredients that exhibit activity across each of the three phases, such as dexpanthenol, are of value in the context of minor wound care and scar management. Key Messages: In addition to treatment and ingredient selection, it is also important to consider broader clinical best practices and self-care options that can be used to optimise the management of minor wounds. An individualised approach that can account for a patient's unique requirements and preferences is critical in achieving effective wound recovery.

Laser scanning microscopy for control of skin decontamination efficacy from airborne particulates using highly absorbent textile nanofiber material in combination with PEG-12 dimethicone.

BACKGROUND: The decontamination of the skin is indispensable if airborne particulate contaminants deposit on the skin surface. Skin washing can have adverse effects as by skin rubbing the particles can be transferred deeply into the hair follicles, where they can be entrapped for a period of more than 10 days. Thus, alternative skin decontamination strategies are necessary. MATERIALS AND METHODS: For imaging the contaminants in the skin, sodium fluorescein-labeled soot particles of submicron size (≈600 nm) were visualized using laser scanning microscopy. RESULTS: In the present ex vivo pilot study on porcine ear skin, it was shown that sodium fluorescein-labeled soot particles of submicron size (≈600 nm) could be efficiently removed from the skin with highly absorbent textile nanofiber material, whose efficacy could be further increased by spraying the contaminated skin area with the viscous fluid PEG-12 dimethicone before textile application. CONCLUSION: In case of skin contamination with particulates, the contact washing should be avoided due to rubbing particles deeply into the hair follicles, where they can accumulate for a long time and induce negative consequences. Efficient skin decontamination could include pretreatment of skin surface with the viscous fluid PEG-12 dimethicone and subsequent application of highly absorbent textile nanofiber material.

Lycopene and Melatonin: Antioxidant Compounds in Cosmetic Formulations.

BACKGROUND: The use of antioxidants has become a common practice in the development of antiaging cosmetics. OBJECTIVE: The aim of this study was to evaluate the clinical efficacy of cosmetic formulations containing lycopene and melatonin antioxidants. METHOD: Thirty-six healthy women from 32 to 65 years were enrolled in this study. The study was carried out for 10 weeks, 2 preconditioning weeks with a control cream without antioxidants, and 8-week test with creams containing antioxidants in study. A multifunctional skin physiology monitor (Courage & Khazaka electronic GmbH®, Germany) was used to measure skin sebum content, hydration, elasticity, erythema index, and melanin index in 4 different regions of the face. RESULTS: There were significant differences between them.

Intradermal Administration of Atrial Natriuretic Peptide Attenuates Cutaneous Vasodilation but Not Sweating in Young Men during Exercise in the Heat.

INTRODUCTION: Prolonged exercise in the heat stimulates plasma release of atrial natriuretic peptide (ANP) in association with dehydration-induced reductions in blood volume. Elevated plasma ANP levels under these conditions may indirectly attenuate cutaneous blood flow and sweating responses due to the effects of this hormone on central blood volume and plasma osmolality and the resulting stimulation of nonthermal reflexes. However, it remains unclear whether cutaneous blood flow and sweating are directly modulated by ANP at the level of the cutaneous end organs (cutaneous microvessels and eccrine sweat glands) during prolonged exercise in the heat. OBJECTIVE: Therefore, we evaluated the effects of local ANP administration on forearm cutaneous vascular conductance (CVC) and local sweat rate (LSR) during rest and exercise in the heat. METHODS: In 9 habitually active young men (26 ± 6 years) CVC and LSR were evaluated at 3 intradermal microdialysis sites continuously perfused with lactated Ringer solution (control) or ANP (0.1 or 1.0 µM). Participants rested in a non-heat-stress condition (25°C) for approximately 60 min followed by 70 min in the heat (35°C). They then performed 50 min of moderate-intensity cycling (approx. 55% VO2 peak), with a 30-min recovery. Thereafter, 50 mM sodium nitroprusside was administered at all sites to elicit maximum CVC, which was subsequently used to normalize all values (CVC%max). RESULTS: No effects of ANP on CVC%max were observed in the non-heat-stress resting condition compared to the untreated control site (both p > 0.05). Conversely during rest in the heat there was an 11% (5-17%) reduction in CVC%max at the 1.0 µM ANP site relative to the untreated control site (p < 0.05). At the end of exercise CVC%max was attenuated by 12% (1-23%) at the 0.1 µM ANP site and by 21% (7-35%) at the 1.0 µM ANP site relative to the untreated control site (all p < 0.05). Conversely, neither concentration of ANP influenced sweating at any time point (all p > 0.05). CONCLUSION: Intradermal ANP administration directly attenuated cutaneous blood flow, but not sweating, in habitually active young men during rest and exercise in the heat.

Protocatechuic Aldehyde Attenuates UVA-Induced Photoaging in Human Dermal Fibroblast Cells by Suppressing MAPKs/AP-1 and NF-κB Signaling Pathways.

Ultraviolet radiation (UV) is a major causative factor of DNA damage, inflammatory responses, reactive oxygen species (ROS) generation and a turnover of various cutaneous lesions resulting in skin photoaging. The purpose of this study is to investigate the protective effect of protocatechuic aldehyde (PA), which is a nature-derived compound, against UVA-induced photoaging by using human dermal fibroblast (HDF) cells. In this study, our results indicated that PA significantly reduced the levels of intracellular ROS, nitric oxide (NO), and prostaglandins-E2 (PGE2) in UVA-irradiated HDF cells. It also inhibited the levels of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expression. Besides, PA significantly suppressed the expression of matrix metalloproteinases-1 (MMP-1) and pro-inflammatory cytokines and promoted collagen synthesis in the UVA-irradiated HDF cells. These events occurred through the regulation of activator protein 1 (AP-1), nuclear factor-κB (NF-κB), and p38 signaling pathways in UVA-irradiated HDF cells. Our findings suggest that PA enhances the protective effect of UVA-irradiated photoaging, which is associated with ROS scavenging, anti-wrinkle, and anti-inflammatory activities. Therefore, PA can be a potential candidate for the provision of a protective effect against UVA-stimulated photoaging in the pharmaceutical and cosmeceutical industries.

From Inflammation to Cutaneous Repair: Topical Application of Lupeol Improves Skin Wound Healing in Rats by Modulating the Cytokine Levels, NF-κB, Ki-67, Growth Factor Expression, and Distribution of Collagen Fibers.

Skin wound healing is a highly complex event that involves different mediators at the cellular and molecular level. Lupeol has been reported to possess different biological activities, such as anti-inflammatory, antioxidant, antidiabetic, and in vitro wound healing properties, which motivated us to proceed with in vivo studies. We aimed to investigate the wound healing effect of lupeol-based cream for 3, 7, and 14 days. Wound excisions were induced on the thoraco-lumbar region of rats and topically treated immediately after injury induction. Macroscopic, histopathological, and immunohistochemical analyses were performed. Cytokine levels were measured by ELISA and gene expression was evaluated by real-time RT-qPCR. Our results showed a strong wound-healing effect of lupeol-based cream after 7 and 14 days. Lupeol treatment caused a reduction in proinflammatory cytokines (TNF-a, IL-1ß, and IL-6) and gene and protein NF-κB expression, and positively altered IL-10 levels, showing anti-inflammatory effects in the three treatment periods. Lupeol treatment showed involvement in the proliferative phase by stimulating the formation of new blood vessels, increasing the immunostaining of Ki-67 and gene expression, and immunolabeling of vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF), and increasing gene expression of transforming growth factor beta-1 (TGF-ß1) after seven days of treatment. Lupeol was also involved in the tissue regeneration phase by increasing the synthesis of collagen fibers noted in the three treatment periods analyzed. Our findings suggest that lupeol may serve as a novel therapeutic option to treat cutaneous wounds by regulating mechanisms involved in the inflammatory, proliferative, and tissue-remodeling phases.

Effects of Apigenin on RBL-2H3, RAW264.7, and HaCaT Cells: Anti-Allergic, Anti-Inflammatory, and Skin-Protective Activities.

Apigenin (4',5,7-trihydroxyflavone, flavonoid) is a phenolic compound that is known to reduce the risk of chronic disease owing to its low toxicity. The first study on apigenin analyzed its effect on histamine release in the 1950s. Since then, anti-mutation and antitumor properties of apigenin have been widely reported. In the present study, we evaluated the apigenin-mediated amelioration of skin disease and investigated its applicability as a functional ingredient, especially in cosmetics. The effect of apigenin on RAW264.7 (murine macrophage), RBL-2H3 (rat basophilic leukemia), and HaCaT (human immortalized keratinocyte) cells were analyzed. Apigenin (100 µM) significantly inhibited nitric oxide (NO) production, cytokine expression (interleukin (IL)-1ß, IL6, cyclooxygenase (COX)-2, and inducible nitric oxide synthase [iNOS]), and phosphorylation of mitogen-activated protein kinase (MAPK) signal molecules, including extracellular signal-regulated kinase (ERK) and c-Jun N-terminal protein kinase (JNK) in RAW264.7 cells. Apigenin (30 M) also inhibited the phosphorylation of signaling molecules (Lyn, Syk, phospholipase Cγ1, ERK, and JNK) and the expression of high-affinity IgE receptor FcεRIα and cytokines (tumor necrosis factor (TNF)-α, IL-4, IL-5, IL-6, IL-13, and COX-2) that are known to induce inflammation and allergic responses in RBL-2H3 cells. Further, apigenin (20 µM) significantly induced the expression of filaggrin, loricrin, aquaporin-3, hyaluronic acid, hyaluronic acid synthase (HAS)-1, HAS-2, and HAS-3 in HaCaT cells that are the main components of the physical barrier of the skin. Moreover, it promoted the expression of human ß-defensin (HBD)-1, HBD-2, HBD-3, and cathelicidin (LL-37) in HaCaT cells. These antimicrobial peptides are known to play an important role in the skin as chemical barriers. Apigenin significantly suppressed the inflammatory and allergic responses of RAW264.7 and RBL cells, respectively, and would, therefore, serve as a potential prophylactic and therapeutic agent for immune-related diseases. Apigenin could also be used to improve the functions of the physical and chemical skin barriers and to alleviate psoriasis, acne, and atopic dermatitis.