The Effect of UVB Irradiation and Oxidative Stress on the Skin Barrier-A New Method to Evaluate Sun Protection Factor Based on Electrical Impedance Spectroscopy

Butin Protects Keratinocytes From Particulate Matter 2.5 and Ultraviolet B-Mediated Damages

BACKGROUND

Butin is a naturally occurring compound with a wide range of medicinal properties, including anti-inflammatory, anti-arthritic, and antioxidant properties. Particulate matter 2.5 (PM2.5) and ultraviolet B (UVB) radiation contribute to skin cell damage via the induction of oxidative stress.

METHODS

This study sought to assess the protective effects of butin against damage triggered by PM2.5 and UVB in human HaCaT keratinocytes. Assessments were performed to evaluate cell viability, apoptosis, and cellular component damage.

RESULTS

Butin exhibited its protective ability via the inhibition of PM2.5-induced reactive oxygen species generation, lipid peroxidation, DNA damage, protein carbonylation, and mitochondrial damage. Butin reduced the PM2.5-induced c-Fos and phospho-c-Jun protein levels as well as mitogen-activated protein kinase. Furthermore, butin mitigated PM2.5- and UVB-induced apoptosis.

CONCLUSION

Butin had the potential as a pharmaceutical candidate for treating skin damage caused by PM2.5 and UVB exposure.

At-Line LC-QTOF-ESI-MS/MS Fractionation of Impatiens balsamina Linn. Coupled With a Simple DPPH for Rapid Identification and Guided Isolation of Antioxidant

INTRODUCTION

Reactive oxygen species (ROS) and ultraviolet (UV) light are significant factors to impair skin disorders. Impatiens balsamina Linn. (IB), a traditional Chinese and Thai herbal medicine, has long been used to treat skin and nail diseases, potentially due to its radical-scavenging properties. However, specific antioxidant compounds in IB have not been well defined.

OBJECTIVE

This work aims to rapidly identify, target, and isolate antioxidant biomarkers in IB using at-line LC-ESI-QTOF-(MS/MS) coupled with a simple DPPH assay and comprehensively investigate the antioxidant activities of IB extract and isolated biomarker.

METHODOLOGY

Following liquid chromatography (LC), the eluent of IB extract was split into two streams (9:1 ratio). The majority was fractionated for DPPH assay in 96-well plates, whereas 10% underwent chemical identification using ESI-QTOF-MS. Antioxidants in IB were identified, targeted, and promptly isolated through transfer from analytical LC to preparative HPLC. IB and the isolated biomarkers were evaluated for antioxidant effects using various antiradical assays and in suppressing ROS induced by UV in skin cells, keratinocytes, and fibroblasts.

RESULTS

Thirty-one chemical constituents were identified, with four tentatively identified as potent antioxidants. Kaempferol emerged as a potential antioxidant biomarker in IB, exhibiting superior antioxidant activity in various in vitro assays compared with positive controls. Both IB extract and kaempferol effectively reduced UVB-induced ROS in skin cells.

CONCLUSION

This study represents the first comprehensive identification of antioxidants and chemical constituents in IB, pinpointing kaempferol as a key antioxidant biomarker. Its rapid identification using at-line techniques holds promise for advancing bioactive compound discovery in herbal medicine.

Electrical Impedance Dermography: Background, Current State, and Emerging Clinical Opportunities

Electrical impedance dermography (EID), based on electrical impedance spectroscopy, is a specific technique for the evaluation of skin disorders that relies upon the application and measurement of painless, alternating electrical current. EID assesses pathological changes to the normal composition and architecture of the skin that influence the flow of electrical current, including changes associated with inflammation, keratinocyte and melanocyte carcinogenesis, and scarring. Assessing the electrical properties of the skin across a range of frequencies and in multiple directions of current flow can provide diagnostic information to aid in the identification of pathologic skin conditions. EID holds the promise of serving as a diagnostic biomarker and potential to be used in skin cancer detection and staging. EID may also be useful as a biomarker in monitoring effectiveness of treatment in individual patients and in therapeutic research. This review highlights ongoing efforts to improve mechanistic understanding of skin electrical changes, study of EID in a variety of clinical contexts, and further refine the technology to find greater clinical use in dermatology and dermatologic research.

Unraveling UVB effects: Catalase activity and molecular alterations in the stratum corneum

AIM

Ultraviolet B (UVB) radiation can compromise the functionality of the skin barrier through various mechanisms. We hypothesize that UVB induce photochemical alterations in the components of the outermost layer of the skin, known as the stratum corneum (SC), and modulate its antioxidative defense mechanisms. Catalase is a well-known antioxidative enzyme found in the SC where it acts to scavenge reactive oxygen species. However, a detailed characterization of acute UVB exposure on the activity of native catalase in the SC is lacking. Moreover, the effects of UVB irradiation on the molecular dynamics and organization of the SC keratin and lipid components remain unclear. Thus, the aim of this work is to characterize consequences of UVB exposure on the structural and antioxidative properties of catalase, as well as on the molecular and global properties of the SC matrix surrounding the enzyme.

EXPERIMENTS

The effect of UVB irradiation on the catalase function is investigated by chronoamperometry with a skin covered oxygen electrode, which probes the activity of native catalase in the SC matrix. Circular dichroism is used to explore changes of the catalase secondary structure, and gel electrophoresis is used to detect fragmentation of the enzyme following the UVB exposure. UVB induced alterations of the SC molecular dynamics and structural features of the SC barrier, as well as its water sorption behavior, are investigated by a complementary set of techniques, including natural abundance 13C polarization transfer solid-state NMR, wide-angle X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, and dynamic vapor sorption microbalance.

FINDINGS

The findings show that UVB exposure impairs the antioxidative function of catalase by deactivating both native catalase in the SC matrix and lyophilized catalase. However, UVB radiation does not alter the secondary structure of the catalase nor induce any observable enzyme fragmentation, which otherwise could explain deactivation of its function. NMR measurements on SC samples show a subtle increase in the molecular mobility of the terminal segments of the SC lipids, accompanied by a decrease in the mobility of lipid chain trans-gauche conformers after high doses of UVB exposure. At the same time, the NMR data suggest increased rigidity of the polypeptide backbone of the keratin filaments, while the molecular mobility of amino acid residues in random coil domains of keratin remain unaffected by UVB irradiation. The FTIR data show a consistent decrease in absorbance associated with lipid bond vibrations, relative to the main protein bands. Collectively, the NMR and FTIR data suggest a small modification in the composition of fluid and solid phases of the SC lipid and protein components after UVB exposure, unrelated to the hydration capacity of the SC tissue. To conclude, UVB deactivation of catalase is anticipated to elevate oxidative stress of the SC, which, when coupled with subtle changes in the molecular characteristics of the SC, may compromise the overall skin health and elevate the likelihood of developing skin disorders.

Methods for skin image analysis and their applications in dermatology and cosmetic research: a comprehensive review

INTRODUCTION

In recent years, several non-invasive imaging methods have been introduced to facilitate studies in dermatology and cosmetic research, almost completely replacing invasive methods such as biopsy. Imaging devices have proven to be useful tools in skin analysis and therapy monitoring. This review aimed to investigate the most recent studies in cosmetic dermatology the imaging technology and methods that are being used to assess skin characteristics and summarize its fundamentals, possible applications, advantages, and limitations, and to give a future perspective to the clinical trials.

EVIDENCE ACQUISITION

For that, a literature review was carried out in the main scientific database platforms and the studies associating skin image analysis with dermatology and cosmetic research were selected and discussed.

EVIDENCE SYNTHESIS

It was possible to infer that skin image analyses are not only practical and effective, but have also become increasingly essential for the skin sciences. The in vivo and real-time image analyses allow a more complete evaluation and the follow-up of the same region for different periods. It was also possible to observe that macroscopic, microscopic, and mesoscopic imaging methods are complementary, allowing different approaches in the same study.

CONCLUSIONS

These technologies are expected to evolve more and more quickly in the near future.

Antioxidant and photoprotective role of latex C-serum from Hevea brasiliensis during 15-week UVB irradiation in male hairless SKH-1 mice

It is known that UVB radiation induces several adverse skin alterations starting from simple photoaging to skin cancer. In addition, it was demonstrated that reactive oxygen species (ROS) were found to be related to cancer development and progression. The aim of study was to examine whether male hairless (SKH-1) mice (Mus musculus) that were subchronically exposed to UVB radiation presented with actinic keratosis (AK) and squamous cell carcinoma lesions, and that treatment with latex C-serum cream significantly prevented abnormal skin development. Data demonstrated for the first time the photoprotective activity of latex C-serum extracted from the rubber tree Hevea brasiliensis var. subconcolor Ducke. Latex C-serum prevented the progression of AK to squamous cell carcinoma in SKH-1 mice, indicating that mice topically treated with latex C-serum presented only AK lesions and treatment with the highest concentration (10%) significantly reduced epidermal thickness, suggesting diminished cell proliferation. Latex C-serum protected the skin of mice against oxidative stress damage, increasing catalase (CAT) activity, regenerating glutathione (GSH) levels, lowering thiobarbituric acid-reactive species (TBARS) production and regenerating the total antioxidant capacity (TAC) of the skin. Evidence that UV radiation in skin induced systemic alterations and erythrocytic analysis indicated that latex C-serum increased CAT activity and GSH levels. Taken together these data indicate that latex C-serum plays an important antioxidant and photoprotective role, preventing serious damage to the skin following exposure to UVB radiation.

Luteolin photo-protects zebrafish from environmental stressor ultraviolet radiation (UVB)

Ultraviolet B wavelength ray radiation (UVB) is an environmental stressor with detrimental effects to the aquatic and human systems but also enhances adverse effects when combined with several other environmental factors such as temperature and pollution. UV rays induce cellular oxidative damage and impair motility. This study aimed to examine the photo-protective activity of flavonoid luteolin against UV-B irradiation-induced oxidative stress and cellular damage using zebrafish. An in-vivo photoaging model was established using UV-B irradiation in zebrafish larvae exposed to 100 mJ/cm2. Data demonstrated that UV-B irradiation of swimming water enhanced production of ROS and superoxide anions as well as depleted total glutathione levels in zebrafish larvae. UV-B irradiation also triggered cellular damage and membrane rupture in zebra fish. Further, 100 mJ/cm2 of UV-B radiation exposure to adult-wild type zebrafish co-exposed with intraperitoneally (ip) injected luteolin upregulated the local neuroendocrine axes by activating vascular endothelial growth factor (VEGF) and elevating levels of pro-inflammatory cytokines IL-1β and TNF-α. Histologically, UV-B irradiation induced skin lesions and locomotory defects with clumping and degeneration of brain glial cells. However, luteolin effectively inhibited the excess production of reactive oxygen species (ROS) and decreased superoxide anion levels induced by UV-B irradiation. Luteolin restored the depleted glutathione levels. In addition, luteolin blocked apoptosis and lipidperoxidation. Luteolin protected adult zebrafish by downregulating the pro-inflammatory cytokine protein expression levels and diminishing VEGF activation. Luteolin also alleviated locomotory defects by inhibiting activation of microglia and inflammatory responses by preventing accumulation of glial cells and vacuolation. Data demonstrate that luteolin may protect zebrafish from UV-B-induced photodamage through DNA-protective, antioxidant and anti-inflammatory responses.

Anti-inflammatory effects of Derris scandens extract on narrowband-ultraviolet B exposed HaCaT human keratinocytes

Narrowband-ultraviolet B (NB-UVB) has been used to treat skin diseases such as psoriasis. Chronic use of NB-UVB might cause skin inflammation and lead to skin cancer. In Thailand, Derris Scandens (Roxb.) Benth. is used as an alternative medicine to nonsteroidal anti-inflammatory drugs (NSAIDs) for low back pain and osteoarthritis. Therefore, this study aimed to evaluate the potential anti-inflammatory effect of Derris scandens extract (DSE) on pre- and post exposed NB-UVB human keratinocytes (HaCaT). The results indicated that DSE could not protect HaCaT from cell morphology changes or DNA fragmentation and could not recover cell proliferation ability from the NB-UVB effects. DSE treatment reduced the expression of genes related to inflammation, collagen degradation, and carcinogenesis, such as IL-1α, IL-1β, IL-6, iNOS, COX-2, MMP-1, MMP-9, and Bax. These results indicated the potential use of DSE as a topical preparation against NB-UVB-induced inflammation, anti-aging, and prevention of skin cancer from phototherapy.

Effect of a hyaluronic acid-based mesotherapeutic injectable on the gene expression of CLOCK and Klotho proteins, and environmentally induced oxidative stress in human skin cells

OBJECTIVE

Normal circadian rhythms are essential to the repair mechanisms of oxidative stress implicated in skin aging. Given reports that hyaluronic acid (HA) homeostasis exhibits a different profile in chronological skin aging, as compared to environmental or extrinsic aging, an improved understanding of the way HA interacts with its surroundings, and the impact of HA injectables in replacing lost HA and encouraging rejuvenation, is of key benefit to skin aging treatments. The objectives of these current studies were twofold. Firstly, to demonstrate the in vitro effects of two lightweight hyaluronic-based injectables on the expression of CLOCK protein in human skin fibroblasts, and their effects on Klotho protein expression as a marker for circadian rhythms in a combined human keratinocyte and Merkel cell model. Secondly, to ascertain whether these findings could be correlated with in vitro effects on various environmental oxidative stress aging markers (blue light, UVA/UVB, Urban Dust, and IR exposures).

METHODS

Oxidative stress studies were aimed to highlight possible protective effects through different challenge conditions in two models, ex vivo human skin explants and in vitro monolayer cultures of normal human dermal fibroblasts (NHDF). The protective effects of the test products were evaluated against an increase of cyclobutene pyrimidine dimers (CPDs) abundance within epidermal section of ex vivo skin explants after UVA/UVB radiation; effects of blue light on gene expression from NHDFs fibroblasts; effects of pollutants (Urban dust, UbD) on gene expression in NHDFs fibroblasts; and an increase of reactive oxygen species (ROS) production by NHDFs fibroblasts after infrared-A radiation. Gene expression was assayed and analyzed utilizing microfluidic TaqMan qPCR arrays. CLOCK expression was measured in young and senescing NHDFs by immunostaining, and Klotho and melatonin expression by immunostaining in Merkel cell-enriched normal adult human epidermal cell cultures.

RESULTS

In an aging culture of mixed keratinocyte and Merkel skin cells, activation of Klotho expression was induced by the application of both HA test products. Moreover, the HA products increase Klotho protein expression in both Merkel cells and keratinocytes. The observed positive effect of the tested products on melatonin receptors 1A and 1B expression in aging Merkel cell culture and keratinocytes is also interesting. HA-Y (developed for patients 25+ years old) stimulated melatonin receptors type 1B expression in aging cell cultures more strongly than HA-S (developed for patients 35-65 years old). In age (stressed) cells, a lower expression of Klotho protein and melatonin receptors 1A and 1B is apparent. The addition of HA-Y and HA-S stimulates their expression thus providing a "protective" effect. The blue light irradiation at 40 J/cm² performed in NHDF fibroblast cultures led to a modification of the expression of several genes, all involved in mechanisms known to be modulated in case of solar radiation stress.

CONCLUSIONS

Although these are preliminary findings, they are the first we know of that demonstrate HA facial injectables having a benefit and possibilities beyond the "physical filling" of the skin. As regards the beneficial effects against blue light-induced oxidative stress, and a return to cellular homeostasis, there is a need to conduct further and more precise investigations into HA-S. Furthermore, the benefit of these HA injectables (Novacutan®) in the modulation of oxidative stressed circadian rhythms widens their potential benefit.

Improvement of irradiation-induced fibroblast damage by α2-macroglobulin through alleviating mitochondrial dysfunction

CONTEXT

α2-Macroglobulin (α2-M) is believed to be a potential anti-irradiation agent, but related mechanisms remains unclear.

OBJECTIVE

We investigated the irradiation protective effect of α2-M.

MATERIALS AND METHODS

A total of 10 Gy dose of irradiation was used to damage human skin fibroblasts. The influence of α2-M (100 µg/mL) on the proliferation, migration, invasion and apoptosis of fibroblasts was observed using Cell Counting Kit-8 (CCK8), wound healing, transwell, and flow cytometry. Malondialdehyde, superoxide dismutase and catalase was measured using related ELISA kits. The levels of mitochondrial membrane potential and calcium were detected using flow cytometry. The expression of transient receptor potential melastatin 2 (TRPM2) was investigated through western blotting and immunofluorescence staining.

RESULTS

High purity of α2-M was isolated from Cohn fraction IV. α2-M significantly increased cell proliferation, migration, invasion, but suppressed cell apoptosis after irradiation. The promotion of cell proliferation, migration and invasion by α2-M exceeded over 50% compared group irradiation. The increased cell ratio in the S phase and decreased cell ratio in the G2 phase induced by irradiation were remarkably reversed by α2-M. α2-M markedly suppressed the increased oxidative stress level caused by irradiation. The mitochondrial damage induced by irradiation was improved by α2-M through inhibiting mitochondrial membrane potential loss, calcium and TRPM2 expression.

DISCUSSION AND CONCLUSIONS

α2-M significantly promoted the decreased fibroblast viability and improved the mitochondria dysfunction caused by irradiation. α2-M might present anti-radiation effect through alleviating mitochondrial dysfunction caused by irradiation. This study could provide a novel understanding about the improvement of α2-M on irradiation-induced injury.

Franz cells for facile biosensor evaluation: A case of HRP/SWCNT-based hydrogen peroxide detection via amperometric and wireless modes

Reducing animal use in biosensor research requires broader use of in vitro methods. In this work, we present a novel application of Franz cells suitable for biosensor development and evaluation in vitro. The work describes how Franz cell can be equipped with electrodes enabling characterization of biosensors in close proximity to skin. As an example of a sensor, hydrogen peroxide biosensor was prepared based on horseradish peroxidase (HRP)/single-walled carbon nanotube (SWCNT)-modified textile. The electrode exhibited lower detection limit of 0.3 μM and sensitivity of 184 μA mM^-1 cm^-2. The ability of this biosensor to monitor H₂O₂ penetration through skin and dialysis membranes was evaluated in Franz cell setup in amperometric and wireless modes. The results also show that catalase activity present in skin is a considerable problem for epidermal sensing of H₂O₂. This work highlights opportunities and obstacles that can be addressed by assessment of biosensors in Franz cell setup before progressing to their testing in animals and humans.

Effects of UV Induced-Photoaging on the Hair Follicle Cycle of C57BL6/J Mice

Purpose

To study the changes in the hair follicle cycle and related stem cells induced by photoaging to establish a mouse model of senescence in hair follicles.

Methods

There were 54 C57BL6/J mice randomly divided into three groups. The UVA group and the UVB group underwent photoaging induced by UV lamps for 8 weeks. Changes in skin and the hair follicle cycle were compared by physical signs, dermoscopy, and hematoxylin and eosin and Masson's staining in each group. Western blot, immunohistochemistry, and RT-qPCR were carried out to test canonical proteins and gene expression of the Wnt signaling pathway in the samples. Immunofluorescence was chosen to show variations in the stem cells related to the hair follicle cycle.

Results

There were more gray hairs in the UVA group than the other groups (P<0.05). Both diameter of the hair shaft and depth of hair root were significantly decreased in the UV groups (P<0.05). Stem cells and melanocytes of the hair follicles were reduced in the UVA group. UV, especially UVB, up-regulated the expression of the Wnt signaling pathway and prolonged anagen and telogen phases in the hair follicles, compared with the control group (P<0.05).

Conclusion

By decreasing the number of stem cells related to hair follicles, UVA induces hair follicle photoaging characterized by hair follicle miniaturization and gray hairs. UV up-regulated the expression of the Wnt signaling pathway, and the hair follicle cycle was significantly prolonged by UVB.

Challenges in the Physical Characterization of Lipid Nanoparticles

Nano-sized drug transporters have become an efficient approach with considerable commercial values. Nanomedicine is not only limited to drug delivery by means of different administration routes, such as intravenous, oral, transdermal, nasal, pulmonary, and more, but also has applications in a multitude of areas, such as a vaccine, antibacterial, diagnostics and imaging, and gene delivery. This review will focus on lipid nanosystems with a wide range of applications, taking into consideration their composition, properties, and physical parameters. However, designing suitable protocol for the physical evaluation of nanoparticles is still conflicting. The main obstacle is concerning the sensitivity, reproducibility, and reliability of the adopted methodology. Some important techniques are compared and discussed in this report. Particularly, a comparison between different techniques involved in (a) the morphologic characterization, such as Cryo-TEM, SEM, and X-ray; (b) the size measurement, such as dynamic light scattering, sedimentation field flow fractionation, and optical microscopy; and (c) surface properties, namely zeta potential measurement, is described. In addition, an amperometric tool in order to investigate antioxidant activity and the response of nanomaterials towards the skin membrane has been presented.

Intense Pulsed Light Attenuates UV-Induced Hyperimmune Response and Pigmentation in Human Skin Cells

The skin of an organism is affected by various environmental factors and fights against aging stress via mechanical and biochemical responses. Photoaging induced by ultraviolet B (UVB) irradiation is common and is the most vital factor in the senescence phenotype of skin, and so, suppression of UVB stress-induced damage is critical. To lessen the UVB-induced hyperimmune response and hyperpigmentation, we investigated the ameliorative effects of intense pulsed light (IPL) treatment on the photoaged phenotype of skin cells. Normal human epidermal keratinocytes and human epidermal melanocytes were exposed to 20 mJ/cm² of UVB. After UVB irradiation, the cells were treated with green (525–530 nm) and yellow (585–592 nm) IPL at various time points prior to the harvest step. Subsequently, various signs of excessive immune response, including expression of proinflammatory and melanogenic genes and proteins, cellular oxidative stress level, and antioxidative enzyme activity, were examined. We found that IPL treatment reduced excessive cutaneous immune reactions by suppressing UVB-induced proinflammatory cytokine expression. IPL treatment prevented hyperpigmentation, and combined treatment with green and yellow IPL synergistically attenuated both processes. IPL treatment may exert protective effects against UVB injury in skin cells by attenuating inflammatory cytokine and melanogenic gene overexpression, possibly by reducing intracellular oxidative stress. IPL treatment also preserves antioxidative enzyme activity under UVB irradiation. This study suggests that IPL treatment is a useful strategy against photoaging, and provides evidence supporting clinical approaches with non-invasive light therapy.

Will mesenchymal stem cells be future directions for treating radiation-induced skin injury?

Radiation-induced skin injury (RISI) is one of the common serious side effects of radiotherapy (RT) for patients with malignant tumors. Mesenchymal stem cells (MSCs) are applied to RISI repair in some clinical cases series except some traditional options. Though direct replacement of damaged cells may be achieved through differentiation capacity of MSCs, more recent data indicate that various cytokines and chemokines secreted by MSCs are involved in synergetic therapy of RISI by anti-inflammatory, immunomodulation, antioxidant, revascularization, and anti-apoptotic activity. In this paper, we not only discussed different sources of MSCs on the treatment of RISI both in preclinical studies and clinical trials, but also summarized the applications and mechanisms of MSCs in other related regenerative fields.

Antioxidant and Anti-inflammatory Effect of Cannabidiol Contributes to the Decreased Lipid Peroxidation of Keratinocytes of Rat Skin Exposed to UV Radiation

There is a great need for compounds with antioxidant and anti-inflammatory properties for protection against UV radiation, which is the most prooxidative physical factor that skin cells are exposed to everyday. Therefore, the aim of the study was to evaluate the mechanism of phytocannabinoid-cannabidiol (CBD) action in vivo on lipid metabolism in keratinocytes of rat skin exposed to UVA/UVB radiation. Our results show that CBD protects keratinocytes against the effects of UVA/UVB radiation by reducing lipid peroxidation products: 4-HNE and 8-isoPGF2α. In addition, CBD significantly increases the level of endocannabinoids, such as anandamide, 2-arachidonylglycerol, and palmitoylethanolamide, and the activation of their receptors CB1/2 or TRPV1. The above changes are due to the protective effect of CBD against the UVA/UVB-induced decrease in the level/activity of superoxide dismutase and the components of the thioredoxin and glutathione systems. CBD also increases the in vivo transcriptional activity of Nrf2 and the expression of its Bach1 inhibitor as well as preventing the UVA/UVB-induced increase in the expression of Nrf2 activators p21, p62, p38, and KAP1 and proinflammatory factors such as NFκB and TNFα. By counteracting oxidative stress and changes in lipid structure in keratinocytes, CBD prevents cellular metabolic disturbances, protecting the epidermis against UV damage.

Does Prolonged Exposure of Environmental Fungi to Ultraviolet Irradiation Change the Pattern of Drug Resistance?

Background: The pathogenic and opportunistic fungal species cause life-threatening infections in immunocompromised patients. The ultraviolet (UV) germicidal irradiation is a well-known method for inactivating a significant number of microorganisms and has wide application for sterilization. Objectives: This study aimed to investigate the effect of ultraviolet C (UV-C) irradiation on the antifungal susceptibility pattern of some filamentous fungi. Methods: The effect of UV-C on the antifungal susceptibility pattern of itraconazole, voriconazole, fluconazole, and amphotericin B against filamentous fungi was examined. Changes in the morphological features of resistant strains following UV-C irradiation were also evaluated using scanning electron microscopy. Results: The results revealed a significant decrease in the number of the surviving spores of strains with the prolongation of UV-C irradiation (0 - 10 to 20 min; P < 0.05). Concerning the morphology of resistant Aspergillus spp., the results of scanning electron microscopy showed a significant increase in the length of irradiated hyphae compared to the non-irradiated hyphae (P < 0.05). In addition, colony count showed a significant decrease (P < 0.05). The findings revealed that UV-C radiation exposure could alter the antifungal susceptibility pattern of Aspergillus spp., such as increasing the minimum inhibitory concentration. Conclusions: Aspergillus spp. can cause systemic infections among lab technicians exposed to different doses of radiation. Moreover, this increase in susceptibility pattern can directly affect the duration of treatment.

Non-invasive skin sampling of tryptophan/kynurenine ratio in vitro towards a skin cancer biomarker

The tryptophan to kynurenine ratio (Trp/Kyn) has been proposed as a cancer biomarker. Non-invasive topical sampling of Trp/Kyn can therefore serve as a promising concept for skin cancer diagnostics. By performing in vitro pig skin permeability studies, we conclude that non-invasive topical sampling of Trp and Kyn is feasible. We explore the influence of different experimental conditions, which are relevant for the clinical in vivo setting, such as pH variations, sampling time, and microbial degradation of Trp and Kyn. The permeabilities of Trp and Kyn are overall similar. However, the permeated Trp/Kyn ratio is generally higher than unity due to endogenous Trp, which should be taken into account to obtain a non-biased Trp/Kyn ratio accurately reflecting systemic concentrations. Additionally, prolonged sampling time is associated with bacterial Trp and Kyn degradation and should be considered in a clinical setting. Finally, the experimental results are supported by the four permeation pathways model, predicting that the hydrophilic Trp and Kyn molecules mainly permeate through lipid defects (i.e., the porous pathway). However, the hydrophobic indole ring of Trp is suggested to result in a small but noticeable relative increase of Trp diffusion via pathways across the SC lipid lamellae, while the shunt pathway is proposed to slightly favor permeation of Kyn relative to Trp.

MiR-4497 mediates oxidative stress and inflammatory injury in keratinocytes induced by ultraviolet B radiation through regulating NF-κB expression

BACKGROUND

To investigate the role and underlying mechanism of miR-4497 in oxidative stress and inflammatory injury in keratinocytes induced by ultraviolet B (UVB) radiation.

METHODS

An injury model of keratinocytes induced by UVB radiation was constructed. RT-qPCR, MTT assay and flow cytometry were adopted to detect miR-4497 expression in HaCaT cells, cell proliferation, and cell apoptosis, respectively. The levels of cytokines TNF-α, IL-18, IL-6 and IL-1β in cell culture supernatant were tested by ELISA. ROS levels in the cells were labeled by DCFH-DA fluorescent probe, and then quantitative fluorescence analysis was performed by flow cytometry. SOD activity in the cells was measured by xanthine oxidase assay kit. Western blot was used to determine NF-κB expression in cytoplasm and nucleus, and p-IκBα expression in the cells.

RESULTS

UVB radiation significantly increased miR-4497 expression in HaCaT cells, inhibited cell proliferation, and promoted cell apoptosis. Meanwhile, UVB radiation caused the promotion of secretion of cytokines TNF-α, IL-18, IL-6 and IL-1β. The production of reactive oxygen species (ROS) was promoted by UVB radiation, while SOD activity was inhibited. Nuclear transfer of NF-κB signal was also induced by UVB radiation. In addition, downregulation of miR-4497 expression significantly inhibited the effects of UVB radiation on cell proliferation, apoptosis, cytokine secretion, redox level and NF-κB signal in HaCaT cells, while overexpression of miR-4497 further enhanced these effects of UVB radiation on HaCaT cells.

CONCLUSIONS

UVB may promote the expression of inflammatory and oxidative stress signals in keratinocytes by upregulating miR-4497 expression, thus mediating cell injury.

Skin hydration dynamics investigated by electrical impedance techniques in vivo and in vitro

Skin is easily accessible for transdermal drug delivery and also attractive for biomarker sampling. These applications are strongly influenced by hydration where elevated hydration generally leads to increased skin permeability. Thus, favorable transdermal delivery and extraction conditions can be easily obtained by exploiting elevated skin hydration. Here, we provide a detailed in vivo and in vitro investigation of the skin hydration dynamics using three techniques based on electrical impedance spectroscopy. Good correlation between in vivo and in vitro results is demonstrated, which implies that simple but realistic in vitro models can be used for further studies related to skin hydration (e.g., cosmetic testing). Importantly, the results show that hydration proceeds in two stages. Firstly, hydration between 5 and 10 min results in a drastic skin impedance change, which is interpreted as filling of superficial voids in skin with conducting electrolyte solution. Secondly, a subtle impedance change is observed over time, which is interpreted as leveling of the water gradient across skin leading to structural relaxation/changes of the macromolecular skin barrier components. With respect to transdermal drug delivery and extraction of biomarkers; 1 h of hydration is suggested to result in beneficial and stable conditions in terms of high skin permeability and extraction efficiency.

Design and Characterization of Ethosomes for Transdermal Delivery of Caffeic Acid

The present investigation describes a formulative study aimed at designing ethosomes for caffeic acid transdermal administration. Since caffeic acid is characterized by antioxidant potential but also high instability, its encapsulation appears to be an interesting strategy. Ethosomes were produced by adding water into a phosphatidylcholine ethanol solution under magnetic stirring. Size distribution and morphology of ethosome were investigated by photon correlation spectroscopy, small-angle X-ray spectroscopy, and cryogenic transmission electron microscopy, while the entrapment capacity of caffeic acid was evaluated by high-performance liquid chromatography. Caffeic acid stability in ethosome was compared to the stability of the molecule in water, determined by mass spectrometry. Ethosome dispersion was thickened by poloxamer 407, obtaining an ethosomal gel that was characterized for rheological behavior and deformability. Caffeic acid diffusion kinetics were determined by Franz cells, while its penetration through skin, as well as its antioxidant activity, were evaluated using a porcine skin membrane–covered biosensor based on oxygen electrode. Ethosome mean diameter was ≈200 nm and almost stable within three months. The entrapment of caffeic acid in ethosome dramatically prolonged drug stability with respect to the aqueous solution, being 77% w/w in ethosome after six months, while in water, an almost complete degradation occurred within one month. The addition of poloxamer slightly modified vesicle structure and size, while it decreased the vesicle deformability. Caffeic acid diffusion coefficients from ethosome and ethosome gel were, respectively, 137- and 33-fold lower with respect to the aqueous solution. At last, the caffeic acid permeation and antioxidant power of ethosome were more intense with respect to the simple solution.

Cannabidiol protects keratinocyte cell membranes following exposure to UVB and hydrogen peroxide

Keratinocytes, the major cell type of the epidermis, are particularly sensitive to environmental factors including exposure to sunlight and chemical agents. Since oxidative stress may arise as a result of these factors, compounds are actively sought that can act as protective agents. Recently, cannabidiol (CBD), a phytocannabinoid found in Cannabis Sativa L., has gained increased interest due to its anti-inflammatory and antioxidant properties, and absence of psychoactive effects. This prompted us to analyze the protective effects of CBD on keratinocytes exposed to UVB irradiation and hydrogen peroxide. Here we show, using liquid chromatography mass spectrometry, that CBD was able to penetrate keratinocytes, and accumulated within the cellular membrane. CBD reduced redox balance shift, towards oxidative stress, caused by exposure UVB/hydrogen peroxide, estimated by superoxide anion radical generation and total antioxidant status and consequently lipid peroxidation level. CBD was found to protect keratinocytes by preventing changes in the composition of the cellular membrane, associated with UVB/hydrogen peroxide damages which included reduced polyunsaturated fatty acid levels, increased sialic acid and lipid peroxidation products (malondialdehyde and 8-isoprostanes) levels. This maintains cell membranes integrity and prevents the release of lactate dehydrogenase. In addition, CBD prevented UVB/hydrogen peroxide-induced reduction of keratinocyte size and zeta potential, and also decreased activity of ATP-binding cassette membrane transporters. Together, these findings suggest that CBD could be a potential protective agent for keratinocytes against the harmful effects of irradiation and chemical environmental factors that cause oxidative stress.

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UVB/H₂O₂ stimulates keratinocytes membrane penetration by CBD.

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CBD protects cells against UVB/H₂O₂ induced redox imbalance.

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CBD maintains membrane integrity by preventing its component modifications.

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CBD decreases activity of ATP-binding cassette membrane transporters.

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CBD could be a potential keratinocytes protector against the harmful factors.