Fisetin Inhibits UVA-Induced Expression of MMP-1 and MMP-3 through the NOX/ROS/MAPK Pathway in Human Dermal Fibroblasts and Human Epidermal Keratinocytes

Fisetin is a flavonoid found in plants and has been reported to be effective in various human diseases. However, the effective mechanisms of ultraviolet-A (UVA)-mediated skin damage are not yet clear. In this study, we investigated the protective mechanisms of fisetin regarding UVA-induced human dermal fibroblasts (HDFs) and human epidermal keratinocytes (HEKs) damages. Fisetin showed a cytoprotective effect against UVA irradiation and suppressed matrix metalloproteinases (MMPs), MMP-1, and MMP-3 expression. In addition, fisetin was rescued, which decreased mRNA levels of pro-inflammatory cytokines, reactive oxygen species production, and the downregulation of MAPK/AP-1 related protein and NADPH oxidase (NOX) mRNA levels. Furthermore, UVA-induced MMP-1 and MMP-3 were effectively inhibited by siRNAs to NOX 1 to 5 in HDFs and HEKs. These results indicate that fisetin suppresses UVA-induced damage through the NOX/ROS/MAPK pathway in HDFs and HEKs.

Summer and spring elbow rashes is a variant of polymorphous light eruption: confirmation by photoprovocation and histopathology in a series of five cases

Background

Summer and spring eruptions on the elbows are a variant of polymorphous light eruption described on clinical and histopathological grounds; however, to our knowledge, they have not been confirmed by photobiological studies.

Objective

Based on photobiological studies, this study aimed to demonstrate the involvement of ultraviolet-A (UVA) radiation in this variant of polymorphous light eruption occurring exclusively on the elbows.

Methods

A series of five patients with polymorphous light eruption lesions on the elbows were included in our study. All patients underwent phototesting and photoprovocation of the skin lesions after exposure to a UVA light source [Philips UVA HPA lamp (400 W)]. All patients underwent punch biopsy and histopathological and immunohistochemical studies with anti-CD123.

Results

In all the cases, UVA irradiation caused the appearance of skin lesions on the elbows with characteristic polymorphous light eruption. Histological data showed edema in the superficial dermis and a perivascular lymphocytic infiltrate compatible with polymorphous light eruption. Immunohistochemical staining for CD1-23 showed negative results.

Conclusions

For the first time, photobiological photoprovocation studies demonstrated that repeated exposure to UVA radiation leads to the generation of skin lesions on the elbows, which are clinically and histologically consistent with summer and spring eruptions, confirming that elbow rash is a variant of polymorphous light eruption.

CircRNA-406918 enhances the degradation of advanced glycation end products in photoaged human dermal fibroblasts via targeting cathepsin D

BACKGROUND

Lysosomal cathepsin D (CTSD) can degrade internalized advanced glycation end products (AGEs) in dermal fibroblasts. CTSD expression is decreased in photoaged fibroblasts, which contributes to intracellular AGEs deposition and further plays a role in AGEs accumulation of photoaged skin. The mechanism under downregulated CTSD expression is unclear.

OBJECTIVE

To explore possible mechanism of regulating CTSD expression in photoaged fibroblasts.

METHODS

Dermal fibroblasts were induced into photoaging with repetitive ultraviolet A (UVA) irradiation. The competing endogenous RNA (ceRNA) networks were constructed to predict candidate circRNAs or miRNAs related with CTSD expression. AGEs-BSA degradation by fibroblasts was studied with flow cytometry, ELISA, and confocal microscopy. Effects of overexpressing circRNA-406918 via lentiviral transduction on CTSD expression, autophagy, AGE-BSA degradation were analyzed in photoaged fibroblasts. The correlation between circRNA-406918 and CTSD expression or AGEs accumulation in sun-exposed and sun-protected skin was studied.

RESULTS

CTSD expression, autophagy, and AGEs-BSA degradation were significantly decreased in photoaged fibroblasts. CircRNA-406918 was identified to regulate CTSD expression, autophagy, and senescence in photoaged fibroblasts. Overexpressing circRNA-406918 potently decreased senescence and increased CTSD expression, autophagic flux, and AGEs-BSA degradation in photoaged fibroblasts. Moreover, circRNA-406918 level was positively correlated with CTSD mRNA expression and negatively associated with AGEs accumulation in photodamaged skin. Further, circRNA-406918 was predicted to mediate CTSD expression through sponging eight miRNAs.

CONCLUSION

These findings suggest that circRNA-406918 regulates CTSD expression and AGEs degradation in UVA-induced photoaged fibroblasts and might exert a role in AGEs accumulation in photoaged skin.

Handelin Reduces Ultraviolet A-Induced Photoaging by Inhibiting Reactive Oxygen Species Generation and Enhancing Autophagy

Photoaging is mainly caused by the exposure of the skin to ultraviolet (UV) radiation. Among them, damage to human dermal fibroblast (HDF) cells caused by ultraviolet A (UVA) is the main cause of skin aging. Researchers have dedicated to identifying natural compounds from plants to fight against UV radiation-induced photoaging. We previously found that extracts from wild chrysanthemum could prevent acute damage and photoaging induced by UV irradiation. As one of the most abundant ingredients in wild chrysanthemum extract, handelin was hypothesized to have the potential to prevent UVA-induced photoaging of skin fibroblast. In the present study, we report the great potential of handelin in combating UVA-induced photoaging of fibroblasts. We firstly demonstrated that handelin was safe for skin fibroblast as high as a concentration of 0.0125 μM, showing no toxicity on the cells and improved cell viability. Furthermore, handelin can reduce UVA-induced cellular senescence, indicated by a reduced proportion of senescence-associated beta-galactose positive cells and the expression of P21. We then verified that handelin pretreatment markedly attenuated the production of reactive oxygen species (ROS) generation after UVA irradiation. Meanwhile, we found that handelin enhances autophagy after UVA irradiation, and autophagy is involved in the quality control of intracellular proteins after UV-induced damage (partially indirectly via ROS). Therefore, these results suggest that handelin has a very high potential as an effective ingredient against UVA-induced skin aging. Moreover, this provides an important basis for further research on the photoprotective mechanism of handelin.

(-)-Epigallocatechin-3-Gallate Protects Human Skin Fibroblasts from Ultraviolet a Induced Photoaging

Background

Ultraviolet (UV) is a common stressor of skin and repeated UVA radiation contributes to photoaging. (-)-Epigallocatechin-3-Gallate (EGCG), as the major polyphenol that is found in green tea, and catechins and have shown considerable antioxidant capacity.

Purpose

Our study aims to explore the effects of EGCG on UVA-induced skin photoaging process and associated mechanisms.

Methods

In this study, human skin fibroblasts (HSFs) were treated with UVA and EGCG, and subsequent changes in cell morphology, telomeres, antioxidant capacity, cell cycle, and related genes were evaluated to examine the role and mechanisms of EGCG in delaying skin photoaging.

Results

HSF exposed to UVA underwent an increase in aging-related biomarkers and telomere shortening. Also, UVA radiation inhibited the secretion of transforming growth factor-beta1 (TGF-β1), induced cell cycle arrest, down-regulated antioxidant enzymes, and promoted the accumulation of oxidative product malondialdehyde (MDA) to cause further damage to cells. Increased expression of matrix metalloproteinases (MMPs), tissue inhibitor of metalloproteinase-1 (TIMP-1), p66 at mRNA levels were also observed after UVA irradiation. EGCG treatment effectively inhibited above damage processes caused by UVA radiation in HSF.

Conclusion

Our study indicated that the potential mechanism of EGCG retarding photoaging is closely related to its powerful antioxidant effects and the ability to regulate the expression of related genes, and the usage of EGCG will be a potential strategy in preventing skin photoaging induced by UVA radiation.

Influence of narrowband ultraviolet B phototherapy on serum folate level in skin of color females: A cross-sectional study

Narrowband ultraviolet B (NB-UVB) (311-312 nm) is widely used for dermatological conditions with a favorable side-effect profile during pregnancy. Recently published data showed that NB-UVB might decrease serum folate level in Fitzpatrick skin phenotype I-III, especially at higher doses; this may predispose newborns to neural tube defects.

Objective

To compare serum folate levels of skin of color females treated with NB-UVB and healthy females of childbearing age, as well as to note whether subsequent complications have been observed, if any.

Methods

Multicenter, cross-sectional study of 30 females (N = 30): 15 female patients undergoing NB-UVB phototherapy as well as 15 age-, gender-, and skin phenotype-matched healthy volunteers who were enrolled into the study after excluding factors known to alter serum folate concentration. NB-UVB exposures were performed 2-3 times a week for at least 8-12 weeks (mean cumulative NB-UVB dose ± standard deviation [SD] was 55 ± 79 J/cm2).

Results

Mean serum folate ± SD in NB-UVB exposed and healthy controls were 10.3 ± 4 and 8.3 ± 3 ng/mL, respectively. This was not a statistically significant difference between the 2 groups (P = .14).

Limitations

Small sample size (N = 30) and a cross-sectional study type.

Conclusion

Cumulative NB-UVB exposure is not associated with a statistically significant difference in serum folate level (P > .05) in skin of color females of childbearing age in comparison to age-, gender-, and skin phenotype-matched healthy females, even with the relatively higher cumulative doses (mean ± SD was 55 ± 79 J/cm2) that have been shown to reduce serum folate level in lighter skin phenotypes.

Photolysis of Chlorine Dioxide under UVA Irradiation: Radical Formation, Application in Treating Micropollutants, Formation of Disinfection Byproducts, and Toxicity under Scenarios Relevant to Potable Reuse and Drinking Water

Conversion of potable reuse water utilities and drinking water utilities from a low-pressure UV/H₂O₂ (LPUV/H₂O₂) advanced oxidation process (AOP) to alternative AOPs in which oxidants can effectively absorb photons and rapidly generate radicals has attracted great interest. Herein, we propose a novel UVA/ClO₂ AOP for different water treatment scenarios because of reduced photon absorption by the background matrix and high molar absorptivity for ClO₂ at UVA wavelengths. While the photolysis of ClO₂ produces ^•Cl + O₂ or ^•ClO + O(³P) via distinct product channels, we determined the parameters needed to accurately model the loss of oxidants and the formation of byproducts and combined a kinetic model with experimental data to determine quantum yields (Φ). Modeling incorporating the optimized Φ simultaneously predicted oxidant loss and the formation of major products -HOCl, Cl^-, and ClO₃^-. We also systematically investigated the removal of three contaminants exhibiting different radical reactivities, the formation of 35 regulated and unregulated halogenated disinfection byproducts (DBPs), DBP-associated toxicity, and N-acetylcysteine thiol reactivity in synthetic or authentic RO permeates/surface waters treated by different AOPs. The kinetic model developed in this study was used to optimize operating conditions to control undesired products and improve contaminant removal efficiency. The results indicate that UVA/ClO₂ can outperform LPUV/H₂O₂ in terms of electrical energy per order of contaminant degradation, disinfection byproduct formation, and toxicity indices.

Comparing the Differences in Slowing Myopia Progression by Riboflavin/Ultraviolet A Scleral Cross-linking before and after Lens-induced Myopia in Guinea Pigs

PURPOSE

To compare the effectiveness and differences in slowing myopia progression in Guinea pigs by riboflavin/ultraviolet A (UVA) scleral cross-linking (sCXL) before and after lens-induced myopia (LIM).

METHODS

Forty 4-week-old Guinea pigs were randomly divided into four groups (n = 10 per group): CXL-A, CXL-B, LIM, and Control groups. The right eyes in CXL-A, CXL-B, LIM groups were treated with -10.00 D lenses from 4 to 10-week old and the left eyes were untreated. In CXL-A and CXL-B groups, riboflavin/UVA sCXL was performed on the right eyes at 4 weeks and 8 weeks of age, respectively. Both eyes were untreated in Control group. The intraocular pressure (IOP), the axial length (AXL), and the refraction were measured in vivo at 4, 8, and 10 weeks of age. At 10 weeks of age, the right eyes were enucleated for the tensile test and transmission electron microscopy observations.

RESULTS

The myopia has been successfully induced in LIM and CXL-B groups during 4-8 weeks. In CXL-A group, the growth rate of AXL and myopic refraction was markedly inhibited during 4-8 weeks and the inhibitory effects diminished during 8-10 weeks. During 8-10 weeks, the growth rate of AXL and myopic refraction in CXL-B were marked suppressed. At 10 weeks of age, the myopia refraction was lower and the AXL was shorter in CXL-A group in comparison to CXL-B group. The IOP was not significantly different among the 4 groups of eyes at 4, 8, and 10 weeks of age. The scleral stiffness, the fibril diameters, and the fibril density of the sclera were significantly increased in CXL-A and CXL-B groups compared to LIM group.

CONCLUSION

Riboflavin/UVA sCXL administrated before and after the myopia modeling could both slow the myopia progression in Guinea pigs. The before-myopia preventative sCXL showed lower myopic refraction in the same age comparison between the cross-linked groups. The effect of riboflavin/UVA sCXL might reduce over time and the long-term effect should be further investigated. This sCXL intervention might control the ultrastructure alterations of the sclera during the myopia remodeling.

Laboratory testing of sunscreens on the US market finds lower in vitro SPF values than on labels and even less UVA protection

Background

New research has attributed increased significance to the causal link between ultraviolet A (UVA) radiation and immunosuppression and carcinogenesis. In the United States, sunscreens are labeled with only their sun protection factor (SPF) and an imprecise term “broad‐spectrum protection.” Sunscreen marketing and efficacy evaluations continue to be based primarily on skin redness (sunburn) or erythema. We sought to evaluate the ultraviolet (UV) protection offered by common sunscreen products on the US market using laboratory‐measured UV‐absorption testing and comparing with computer‐modeled protection and the labeled SPF values. This approach enables an investigation of the relationship between the labeled SPF and measured UVA protection, a factor that is ignored in current regulations.

Methods

Fifty‐one sunscreen products for sale in the United States with SPF values from 15 to 110 and labeled as providing broad‐spectrum protection were tested using a commercial laboratory. All products were evaluated using the ISO 24443:2012 method for sunscreen effectiveness. The final absorbance spectra were used for analysis of in vitro UV protection.

Results

In vitro SPF values from laboratory‐measured UV absorption and computer modeling were on average just 59 and 42 percent of the labeled SPF. The majority of products provided significantly lower UVA protection with the average unweighted UVA protection factor just 24 percent of the labeled SPF.

Conclusion

Regulations and marketplace forces promote sunscreens that reduce sunburn instead of products that provide better, more broad‐spectrum UV protection. The production and use of products with broad spectrum UV protection should be incentivized, removing the emphasis on sunburn protection and ending testing on people.

The Attenuated Secretion of Hyaluronan by UVA-Exposed Human Fibroblasts Is Associated with Up- and Downregulation of HYBID and HAS2 Expression via Activated and Inactivated Signaling of the p38/ATF2 and JAK2/STAT3 Cascades

Little is known about the effects on hyaluronan (HA) metabolism of UVA radiation. This study demonstrates that the secretion of HA by human dermal fibroblasts (HDFs) is downregulated by UVA, accompanied by the down- and upregulation of mRNA and protein levels of the HA-synthesizing enzyme (HAS2) and the HA-degrading protein, HYaluronan Binding protein Involved in HA Depolymerization(HYBID), respectively. Signaling analysis revealed that the exposure distinctly elicits activation of the p38/MSK1/CREB/c-Fos/AP-1 axis, the JNK/c-Jun axis, and the p38/ATF-2 axis, but downregulates the phosphorylation of NF-kB and JAK/STAT3. A signal inhibition study demonstrated that the inhibition of p38 significantly abrogates the UVA-accentuated mRNA level of HYBID. Furthermore, the inhibition of STAT3 significantly downregulates the level of HAS2 mRNA in non-UVA exposed HDFs. Analysis using siRNAs demonstrated that transfection of ATF-2 siRNA but not c-Fos siRNA abrogates the increased protein level of HYBID in UVA-exposed HDFs. An inhibitor of protein tyrosine phosphatase but not of protein serine/threonine phosphatase restored the diminished phosphorylation level of STAT3 at Tyr 705, accompanied by a significant abolishing effect on the decreased mRNA expression level of HAS2. Silencing with a protein tyrosine phosphatase PTP-Meg2 siRNA revealed that it abrogates the decreased phosphorylation of STAT3 at Tyr 705 in UVA-exposed HDFs. These findings suggest that the UVA-induced decrease in HA secretion by HDFs is attributable to the down- and upregulation of HAS2 and HYBID expression, respectively, changes that are mainly ascribed to the inactivated signaling of the STAT3 axis due to the activated tyrosine protein phosphatase PTP-Meg2 and the activated signaling of the p38/ATF2 axis, respectively.

Ultraviolet A rush hardening for chronic actinic dermatitis: Pilot treatment outcomes

Chronic actinic dermatitis (CAD) is a common debilitating photodermatosis. Patients often have to completely avoid outdoor activities, which severely impacts their quality of life. Phototherapy is effective for CAD and seems to increase patients' tolerance towards sunlight and consequently decrease the extent of disease. Unfortunately, the slower onset and time-consuming nature of phototherapy limits the clinical application. Considering the effectiveness and time-saving nature of ultraviolet (UV)-A rush hardening in solar urticaria, we performed a pilot study to determine whether UV-A rush hardening is effective in CAD. Six patients with CAD were exposed to multiple sessions of UV-A for 4-5 days at 1-h intervals/day. Subsequently, maintenance UV-A exposure was performed at 1-2-week intervals. Phototesting at baseline showed that three patients were sensitive to both UV-A and -B, and the other three patients only showed UV-A sensitivity. All of the patients responded well to UV-A rush hardening and four (67%) maintained a good remission status after 1 year. The results of this pilot study suggest that UV-A rush hardening phototherapy is effective and well tolerated in the treatment of CAD, while future larger prospective studies using objective scores of disease activity and quality of life are needed.

Circular RNA expression profiles significantly altered in UVA-irradiated human dermal fibroblasts

Circular RNAs (circRNAs) have been previously implicated in number of diseases. However, the roles of circRNAs in photoaging remain elusive. In the present study, to understand if photoaging influences the levels of circRNA expression, the expression of circRNAs in ultraviolet A (UVA)-irradiated human dermal fibroblasts were profiled. A total of 128 circRNAs were identified to be differentially expressed (fold change >1.5; P<0.05) after UVA exposure, including 39 upregulated and 89 downregulated circRNAs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes biological pathway analyses indicated that the differentially expressed circRNAs were associated with extracellular matrix organization and metabolism. The present study revealed an altered circRNA expression pattern in human dermal fibroblasts following UVA-irradiation. These results provide not only a basis for in-depth study of the mechanism of skin photoaging but also a new possibility for the prevention and treatment of photoaging and associated skin diseases.

Enzyme-Treated Zizania latifolia Ethanol Extract Protects from UVA Irradiation-Induced Wrinkle Formation via Inhibition of Lysosome Exocytosis and Reactive Oxygen Species Generation

Ultraviolet A (UVA) is a risk factor for photoaging and wrinkle formation. Zizania latifolia is an herbaceous perennial plant. It contains many bioactive compounds such as tricin that show antioxidative and anti-inflammatory effects. The aim of this study was to investigate the antiwrinkle effect of a mixture of hydrolytic enzyme (cellulase, hemicellulase and pectinase)-treated Z. latifolia extract (ZLE) and tricin on UVA-irradiated human dermal fibroblasts (HDFs) and SKH-1 hairless mice. Treatment of UVA-irradiated HDF cells with ZLE and tricin significantly decreased UVA induced-plasma membrane rupture, generation of ROS, expression levels of total and secreted lysosomal associated membrane protein (LAMP-1), cathepsin B and metalloproteinases (MMPs) and inhibited NF-κB activation. In the animal study, UVA-damaged epidermal and dermal tissues were repaired by the ZLE and tricin treatments. Administration of ZLE or tricin to UVA-irradiated animals recovered skin surface moisture and collagen fiber in dermal tissue. Treatment of ZLE or tricin decreased wrinkle formation, secretion of MMPs and expression levels of vascular endothelial growth factor (VEGF) and cathepsin B, and increased the expression level of collagen-1 in UVA-irradiated animals. Overall, the ZLE and tricin treatments decreased the skin damage induced by UVA irradiation via inhibition of lysosomal exocytosis and ROS generation. Therefore, ZLE and tricin are promising as antiwrinkle and antiphotoaging agents.

Novel cannabidiol sunscreen protects keratinocytes and melanocytes against ultraviolet B radiation

Cannabidiol (CBD), a natural occurring phytocannabinoid, is used extensively in consumer products ranging from foods to shampoos, topical oils and lotions. Several studies demonstrated the anti-inflammatory and antioxidative properties of cannabidiol. Nevertheless, the role of cannabidiol use in sunscreens is largely unknown as no studies on its effect on keratinocytes or melanocytes exist. As such, we aimed to explore the effect of CBD on keratinocyte and melanocyte viability following ultraviolet B (UVB) irradiation. CBD exhibited a dose-dependent protective effect on both keratinocytes and melanocyte viability. Further, since CBD does not demonstrate absorption in the UVB spectra, we speculate that the protective effect is due to reduction in reactive oxygen species. To our knowledge, this is the first study demonstrating the protective effect of CBD on keratinocytes and melanocytes irradiated with UVB.

Conjunctival Ultraviolet Autofluorescence as a Measure of Riboflavin and Ultraviolet and Accelerated Cross-Linking Exposure in Keratoconic Patients

Purpose: The study was performed to analyze the prevalence of the conjunctival ultraviolet autofluorescence (CUVAF) area in keratoconic eyes and changes caused by UVA-irradiation as a component of accelerated corneal cross-linking (aCXL). Methods: The study group involved 20 keratoconic patients subjected to aCXL surgery in one eye. The comparative group consisted of 111 age- and sex-matched patients with healthy corneas. The images of the anterior segment in both patient groups were taken using a Coroneo camera. In the study group the photos were taken before and immediately after the surgery, and 7 and 30 days following the procedure. Results: Nasal and temporal autofluorescence area (AN+T) were significantly smaller in a keratoconic patients group compared to control group (p = 0.0001). Patients with the third stage of keratoconus had significantly higher AN+T (p = 0.0277) compared with individuals with lower stage keratoconus. No statistically significant CUVAF changes were observed after the aCXL procedure. In keratoconic patients with primary CUVAF undergoing aCXL, a temporary fast enlargement of the autofluorescence area was observed. Conclusions: The eyes undergoing the aCXL procedure showed no difference in the size of the CUVAF area but such patients should be in strict follow-up in order to reveal UV-related ocular surface diseases.

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.

Silibinin and ellagic acid increase the expression of insulin receptor substrate 1 protein in ultraviolet irradiated rat skin

Daily exposure to ultraviolet (UV) light induces inflammation and tumorigenesis in the skin. Silibinin and ellagic acid are natural products that exhibit anti-inflammatory and anti-tumorigenic properties. Insulin receptor substrate protein 1 (IRS1) is important for skin homeostasis and physiology, but its activity following UV radiation remains unclear. We investigated the effects of ellagic acid and silibinin on IRS1 expression in ultraviolet A (UVA) and ultraviolet B (UVB) irradiated rat skin. Forty-two female Wistar rats were divided randomly into six groups of seven animals. The dorsal skin of rats was exposed to UVA + UVB, then treated with ellagic acid and silibinin by gavage. IRS1 expression in skin tissues was determined by western blot analysis. IRS1 expression increased significantly following treatment with ellagic acid and silibinin in UVA + UVB irradiated skin compared to the UVA + UVB only group. After UVA + UVB treatment, ellagic acid effected greater induction of IRS1 expression than silibinin. Our findings suggest that the photoprotective roles of ellagic acid and silibinin may be due to induction of IRS1 expression in UVA + UVB treated rat skin.

eIF2 alpha phosphorylation alleviates UVA-induced HO-1 expression in mouse epidermal cells

Ultraviolet A (UVA) irradiation is a potential environmental stressor, which contributes to inflammation, photoaging, and carcinogenesis. UVA causes endoplasmic reticulum stress, hence phosphorylates the α subunit of eIF2. Meanwhile, UVA also induces expression of haem oxygenase-1 (HO-1) and nuclear factor erythroid-derived two related factor 2 (Nrf2) in human skin cells. In mouse JB6 cell, we found high dose UVA could change cell morphology, cause cell viability loss. UVA irradiation activated phosphorylation of eIF2α and Nrf2-HO-1 pathway in a dose-dependent manner. Besides, modulation of eIF2α phosphorylation status could alter expression pattern of Nrf2-HO-1 signalling. Salubrinal, a selective inhibitor of eIF2α dephosphorylation, increased the S phase in cell cycle of JB6 cells after UVA irradiation, suggesting phosphorylation status of eIF2α may affect cellular homeostasis under UVA irradiation. The study directed to further acknowledge about the relationship of UVA-induced eIF2α phosphorylation and Nrf2-HO-1 pathway, which may play a role in phototherapy and photo protection.

Ultraviolet-A1 phototherapy in Asian skin: A review of 159 cases in Singapore

Background

Ultraviolet-A1 phototherapy has been used to treat many inflammatory dermatoses.

Aims

To determine the efficacy and safety of ultraviolet-A1 phototherapy in Asian skin.

Materials and Methods

We performed a review of records of patients undergoing ultraviolet-A1 phototherapy at our dermatology unit in Singapore from January 2007 to January 2011. Their electronic medical records were reviewed and a standardized questionnaire was filled up for data collection and tabulation. Chi-square or Fisher's exact tests were used to compare the difference in response between various groups for each characteristic. P value of < 0.05 was considered statistically significant.

Results

Our study comprised of 159 patients, of which 103 were patients with hand and foot eczema, 21 with atopic dermatitis, 17 with scleroderma and the remaining with miscellaneous dermatoses. Of these patients, 47.6% of patients with hand and feet eczema had good response after 10 sessions, which increased to 75% after 20 sessions and to 84.6% after 30 sessions. After 10 sessions, 47.6% of patients with atopic dermatitis had good response, which increased to 66.7% after 20 sessions. After 30 sessions, all the three remaining patients with atopic dermatitis experienced good response. For patients with scleroderma, only 11.8 and 10% had good response after 10 and 20 sessions, respectively, which increased to 40% after 30 sessions.

Limitations

Limitations of our study include its retrospective design and, consequently, the lack of standardized treatment protocol, as well as subjective assessment in terms of clinical improvement.

Conclusions

Ultraviolet-A1 phototherapy appears to be efficacious for the treatment of hand and foot eczema as well as atopic dermatitis. However, in patients with scleroderma, the response was partial and needed a longer duration of treatment.

Extracorporeal Photopheresis-An Overview

Extracorporeal photopheresis (ECP) has been in clinical use for over three decades after receiving FDA approval for the palliative treatment of the Sézary Syndrome variant of cutaneous T-cell lymphoma (CTCL) in 1988. After the first positive experiences with CTCL, additional indications have been successfully explored including areas such as graft-vs.-host disease (GVHD), scleroderma, and solid organ transplantation. The mechanism of action is still not fully resolved, but important steps in understanding ECP in recent years have been very informative. Originally, the primary hypothesis stated that psoralen and ultraviolet A (UVA) in combination induce apoptosis in the treated immune cells. This view shifted in favor of dendritic cell initiation, modification of the cytokine profile and stimulation of several T-cell lineages, in particular regulatory T-cells. A number of ECP guidelines have been produced to optimize treatment regimens in the clinical context. In CTCL, enough evidence is available for the use of ECP as a first line treatment for Sézary Syndrome (SS), but also as a second line or rescue treatment in therapy-refractory forms of mycosis fungoides (MF). ECP in the treatment of acute and chronic GVHD has shown promising results as second line therapy in steroid-refractory presentations. In solid organ transplantation, ECP has been used to increase tissue tolerance and decrease infections with opportunistic pathogens, attributed to the use of high doses of immunosuppressive medication. Infection with cytomegalovirus (CMV) remains a limiting factor affecting survival in solid organ transplantation and the role of ECP will be discussed in this review. A trend toward prophylactic use of ECP can be observed and may further contribute to improve the outcome in many patients. To further deepen our knowledge of ECP and thus facilitate its use in patients that potentially benefit most from it, future prospective randomized trials are urgently needed in this rapidly growing field. The aim of this review is to (1) introduce the method, (2) give an overview where ECP has shown promising effects and has become an essential part of treatment protocols, and (3) to give recommendations on how to proceed in numerous indications.

Thai herbal antipyretic 22 formula (APF22) inhibits UVA-mediated melanogenesis through activation of Nrf2-regulated antioxidant defense

Thai herbal antipyretic 22 formula (APF22), a polyherbal formula, has been traditionally used to treat dermatologic problems including hyperpigmentation. Exposure of the skin to ultraviolet A (UVA) causes abnormal melanin production induced by photooxidative stress. This study thus aimed to investigate the protective effects of APF22 extracts and phenolic compounds, ferulic acid (FA), and gallic acid (GA; used as positive control and reference compounds), on melanogenesis through modulation of nuclear factor E2-related factor 2 (Nrf2) signaling and antioxidant defenses in mouse melanoma (B16F10) cells exposed to UVA. Our results revealed that the APF22 extracts, FA, and GA reduced melanin synthesis as well as activity and protein levels of tyrosinase in UVA-irradiated B16F10 cells. Moreover, APF22 extracts and both FA and GA were able to activate Nrf2-antioxidant response element signaling and promote antioxidant defenses including glutathione, catalase, glutathione peroxidase, and the glutathione-S-transferase at both mRNA and enzyme activity levels in irradiated cells. In conclusion, APF22 extracts suppressed UVA-mediated melanogenesis in B16F10 cells possibly via redox mechanisms involving activation of Nrf2 signaling and upregulation of antioxidant defenses. Moreover, pharmacological action of the APF22 extracts may be attributed to the phenolic compounds, FA, and GA, probably serving as the APF22's active compounds.

Efficacy of iontophoresis-assisted epithelium-on corneal cross-linking for keratoconus

Corneal cross-linking (CXL) is a noninvasive therapeutic procedure for keratoconus that is aimed at improving corneal biomechanical properties by induction of covalent cross-links between stromal proteins. It is accomplished by ultraviolet A (UVA) radiation of the cornea, which is first saturated with photosensitizing riboflavin. It has been shown that standard epithelium-off CXL (S-CXL) is efficacious, and it has been recommended as the standard of care procedure for keratoconus. However, epithelial removal leads to pain, transient vision loss, and a higher risk of corneal infection. To avoid these disadvantages, transepithelial CXL was developed. Recently, iontophoresis has been adopted to increase riboflavin penetration through the epithelium. Several clinical observations have demonstrated the safety and efficacy of iontophoresis-assisted epithelium-on CXL (I-CXL) for keratoconus. This review aimed to provide a comprehensive summary of the published studies regarding I-CXL and a comparison between I-CXL and S-CXL. All articles used in this review were mainly retrieved from the PubMed database. Original articles and reviews were selected if they were related to the I-CXL technique or related to the comparison between I-CXL and S-CXL.

The potent pro-oxidant activity of rhododendrol-eumelanin is enhanced by ultraviolet A radiation

RS-4-(4-hydroxyphenyl)-2-butanol (rhododendrol, RD), a skin-whitening agent, is known to induce leukoderma in some consumers. To explore the mechanism underlying this effect, we previously showed that the oxidation of RD with mushroom or human tyrosinase produces cytotoxic quinone oxidation products and RD-eumelanin exerts a potent pro-oxidant activity. Cellular antioxidants were oxidized by RD-eumelanin with a concomitant production of H₂ O₂ . In this study, we examined whether this pro-oxidant activity of RD-eumelanin is enhanced by ultraviolet A (UVA) radiation because most RD-induced leukoderma lesions are found in sun-exposed areas. Exposure to a physiological level of UVA (3.5 mW/cm² ) induced a two to fourfold increase in the rates of oxidation of GSH, cysteine, ascorbic acid, and NADH. This oxidation was oxygen-dependent and was accompanied by the production of H₂ O₂ . These results suggest that RD-eumelanin is cytotoxic to melanocytes through its potent pro-oxidant activity that is enhanced by UVA radiation.

GSK126 (EZH2 inhibitor) interferes with ultraviolet A radiation-induced photoaging of human skin fibroblast cells

Polycomb group genes (PcG) encode chromatin modification proteins that are involved in the epigenetic regulation of cell differentiation, proliferation and the aging processes. The key subunit of the PcG complex, enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2), has a central role in a variety of mechanisms, such as the formation of chromatin structure, gene expression regulation and DNA damage. In the present study, ultraviolet A (UVA) was used to radiate human dermal fibroblasts in order to construct a photo-aged cell model. Subsequently, the cell viability assay, Hoechst staining, apoptosis detection using flow cytometry, senescence-associated β-galactosidase (SA-β-gal) staining and erythrocyte exclusion experiments were performed. GSK126, a histone methylation enzyme inhibitor of EZH2, was used as an experimental factor. Results suggested that GSK126 downregulated the mRNA expression levels of EZH2 and upregulated the mRNA expression levels of BMI-1. Notably, GSK126 affected the transcription of various photoaging-related genes and thus protected against photoaging induced by UVA radiation.

Biochemical Mechanism of Rhododendrol-Induced Leukoderma

RS-4-(4-hydroxyphenyl)-2-butanol (rhododendrol (RD))-a skin-whitening ingredient-was reported to induce leukoderma in some consumers. We have examined the biochemical basis of the RD-induced leukoderma by elucidating the metabolic fate of RD in the course of tyrosinase-catalyzed oxidation. We found that the oxidation of racemic RD by mushroom tyrosinase rapidly produces RD-quinone, which gives rise to secondary quinone products. Subsequently, we confirmed that human tyrosinase is able to oxidize both enantiomers of RD. We then showed that B16 cells exposed to RD produce high levels of RD-pheomelanin and protein-SH adducts of RD-quinone. Our recent studies showed that RD-eumelanin-an oxidation product of RD-exhibits a potent pro-oxidant activity that is enhanced by ultraviolet-A radiation. In this review, we summarize our biochemical findings on the tyrosinase-dependent metabolism of RD and related studies by other research groups. The results suggest two major mechanisms of cytotoxicity to melanocytes. One is the cytotoxicity of RD-quinone through binding with sulfhydryl proteins that leads to the inactivation of sulfhydryl enzymes and protein denaturation that leads to endoplasmic reticulum stress. The other mechanism is the pro-oxidant activity of RD-derived melanins that leads to oxidative stress resulting from the depletion of antioxidants and the generation of reactive oxygen radicals.

Evaluation of bacterial inactivation in random donor platelets and single-donor apheresis platelets by the INTERCEPT blood system

BACKGROUND:

Blood transfusion of contaminated components is a potential source of sepsis by a wide range of known and unknown pathogens. Collection mechanism and storage conditions of platelets make them vulnerable for bacterial contamination. Several interventions aim to reduce the transfusion of contaminated platelet units; however, data suggest that contaminated platelet transfusion remains very common.

AIM:

A pathogen inactivation system, “INTERCEPT”, to inactivate bacteria in deliberately contaminated platelet units was implemented and evaluated.

MATERIALS AND METHODS:

Five single-donor platelets (SDP) and five random donor platelets (RDP) were prepared after prior consent of donors. Both SDP and RDP units were deliberately contaminated by stable stock ATCC Staphylococcus aureus and Escherichia coli, respectively, with a known concentration of stock culture. Control samples were taken from the infected units and bacterial concentrations were quantified. The units were treated for pathogen inactivation with the INTERCEPT (Cerus Corporation, Concord, CA) Blood system for platelets (Amotosalen/UVA), as per the manufacturer's instructions for use. Post illumination, test samples were analyzed for any bacterial growth.

RESULTS:

Post-illumination test samples did not result in any bacterial growth. A complete reduction of >6 log₁₀S. aureus in SDP units and >6 log₁₀Escherichia coli in RDP units was achieved.

CONCLUSION:

The INTERCEPT system has been shown to be very effective in our study for bacterial inactivation. Implementation of INTERCEPT may be used as a mitigation against any potential bacterial contamination in platelet components.

Photodynamically-induced Apoptosis Due to Ultraviolet A in the Presence of Lomefloxacin in Human Promyelocytic Leukemia Cells

Lomefloxacin (LFX) is a widely used fluoroquinolone antimicrobial agent that plays an important role in the treatment of human and animal infections; however, it has been reported to cause phototoxicity. In this study, we investigated the induction of apoptosis due to ultraviolet A (UVA) light in the presence and absence of LFX in HL-60 human promyelocytic leukemia cells. HL-60 cells were exposed to UVA at an intensity of 1.1 mW/cm² for 20 min in the presence and absence of LFX, and the induction of apoptosis was examined by analyzing cell morphology, DNA fragmentation, and caspase-3 activity. Cells treated with 100 μM LFX and UVA clearly showed membrane blebbing and cell shrinkage. The proportion of apoptotic cells was significantly higher in cells treated with both UVA and LFX than in those treated with UVA or LFX alone. In addition, DNA ladder formation and caspase-3 activation were observed in cells treated with both UVA and LFX. A significant reduction in the number of UVA-induced apoptotic cells and caspase-3 activation was observed when histidine was present, which suggested that photodynamically-generated singlet oxygen is an important mediator of apoptosis. These results indicate that the combination of UVA and LFX induces apoptosis in HL-60 cells.

Sunbeds with UVB radiation can produce physiological levels of serum 25-Hydroxyvitamin D in healthy volunteers

Vitamin D₃ is produced in the skin in response to UVB irradiation, from either sun exposure or UVB sunbeds. The objective of the current study was to characterize serum 25(OH)D response to regular sunbed use from several lamp outputs following their respective time exposure recommendations. There were three groups that tanned over 12 weeks during the winter months in dedicated sunbeds based on lamp outputs (100 W and 160 W low pressure fluorescent and 700 W high pressure filtered metal halide lamps) and a control group provided serum 25(OH)D samples at baseline and end-of-study. Tanning session lengths were calculated based on Health Canada guidelines to stay below the erythema levels. Mean 25(OH)D were increased by an average of 42 nmol/L in the sunbeds that used 100 W and 160 W fluorescents. Change in 25(OH)D was dependent on baseline 25(OH)D levels and sunbed (p = 0.003) and age (p = 0.03), but was not affected by gender, BMI, Fitzpatrick type or cumulative length of tanning sessions. There was no significant increase in 25(OH)D levels in participants using the 700 W filtered metal halide lamp sunbed or in the control participants. Skin pigmentation, ITA°, was markedly increased in all tanners and skin lightness, L*, significantly decreased at 12 weeks. Both L* and ITA° were significantly correlated with 25(OH)D concentrations for the sunbeds with fluorescent lamps emitting UVB (100 W and 160W). Participants following standardized exposure schedules meeting Health Canada regulations in sunbeds irradiating adequate UVB showed continuous increases of 25(OH)D to physiological levels even after producing a tan in a controlled manner.

ClinicalTrials.gov Registration: NCT02334592

Phototherapy in systemic sclerosis: Review

Systemic scleroderma-also known as systemic sclerosis (SSc)-is a chronic systemic connective tissue disease characterized by collagen deposition in cutaneous and internal organs, leading to skin sclerosis and multiple organ fibrosis. The pathogenesis is complex and remains poorly understood. Treatment is based on organ involvement and requires a multidisciplinary approach. Skin sclerosis can cause disability, leading to decreasing quality of life. Various systemic antifibrotic therapies have been used; however, most have unsatisfactory results. Recently, phototherapy and in particular ultraviolet A (UVA) has been used to treat skin sclerosis in SSc patients with satisfactory results. The main mechanisms include lymphocyte apoptosis, cytokine alteration, inhibition of collagen synthesis and increased collagenase production, and neovascularization, leading to the breakdown of collagen fibrils resulting in skin softening or even healing digital ulcers. Most studies reported that psoralen plus UVA (PUVA) and UVA1 phototherapy improved clinical outcomes vis-à-vis skin sclerosis, joint mobility, ulcers, and histopathology. PUVA and UVA1 phototherapy therefore have potential as an alternative or adjunctive therapy for patients with SSc.

Polycomb group proteins: Novel molecules associated with ultraviolet A-induced photoaging of human skin

Epigenetic repressor polycomb group (PcG) proteins are thought to serve a role in a number of cellular processes, including carcinogenesis, senescence, apoptosis and DNA repair. In the present study, long-wave ultraviolet A (UVA) was used to irradiate human skin fibroblasts (HSFs) and embryonic skin fibroblasts (ESFs) in order to simulate photoaging of the skin. The results of cell proliferation, apoptosis, hyaluronic acid (HA) content and reverse transcription-quantitative polymerase chain reaction assays revealed that the expression levels of genes encoding key PcG proteins (BMI-1 and EZH2) were altered. In addition, the expression levels of these genes were associated with the expression of enzymes that regulate HA synthesis. Furthermore, the expression levels of PcG proteins differed between HSFs and ESFs, suggesting that PcG proteins serve a role in altering HA synthesis during the UVA-induced fibroblast aging process. This signaling pathway may represent a novel molecular mechanism regulating the photoaging of the skin. The findings of the present study provide important insights into the underlying mechanisms of photoaging of the human skin. Further studies are required to clarify the molecular mechanisms underling skin aging and to identify targets for the clinical treatment of photoaging.

Scleral wound healing with cross-link technique using riboflavin and ultraviolet A on rabbit eyes

Purpose

The aim of study was to evaluate the cross-link using riboflavin and ultraviolet A (UVA) for improving scleral wound healing.

Materials and methods

This was an experimental study involving four New Zealand rabbits (eight eyes). Therapy procedure was chosen for the right eye and control procedure for the left one. UVA irradiation of 365 nm with a surface irradiance of 3 mW/cm² and a photosensitizer of riboflavin drops were applied for 30 minutes on the right eye at 2 mm from the limbus. Sclerotomy incision was performed at 2 mm from the limbus in both right (on the cross-link-treated area) and left eye. Then, 30 days after surgery, a morphological analysis and histological staining with hematoxylin–eosin and picrosirius red were performed, and the sclerotomy cicatrization of right and left eyes was compared. The variables investigated were as follows: sclerotomy incision pictures and measurements were made using the ImageJ Software. Scleral thickness was measured (employing the anterior optical coherence tomography and the digital caliper). Collagen fiber density stained with picrosirius red staining was measured using the Image Pro Plus software.

Results

The morphological analysis showed that in all samples, the right eye presented sclerotomy closure, and in two eyes, among them, there were no visible edges of the sclerotomies incision. The left eye presented sclerotomy closure and incision edges. The Image Pro demonstrated a higher density of collagen fibers in the right eye when compared to the one. The statistical analysis was significant when compared to the collagen fiber density in the treated eyes with the control eyes.

Conclusion

The cross-link procedure resulted in a better sclerotomy wound healing.

25-Hydroxyvitamin-D3 serum modulation after use of sunbeds compliant with European Union standards: A randomized open observational controlled trial

BACKGROUND

Regular use of sunbed exposure has been reported to increase 25-hydroxyvitamin-D3 [25(OH)D] serum levels. However, the influence of sunbeds compliant with the recent European Union standard EN-60335-2-27 on 25(OH)D serum levels is unknown.

OBJECTIVE

We investigated the impact of standard sunbed use compliant with the European Union standard on 25(OH)D serum modulation and well-being.

METHODS

In a randomized controlled study, 25(OH)D serum levels were measured at enrollment, after 1 week, and after completion of the 12-week period of sunbed use with twice weekly exposure and compared with the control group without any sunbed exposure.

RESULTS

In the sunbed intervention group (N = 31), a 27% increase of mean 25(OH)D levels was noted 1 week after starting sunbed use (P < .01). However, after 12 weeks, mean 25(OH)D levels had declined and were no longer different from baseline (P = .06). After 12 weeks, 25(OH)D levels did not differ between the intervention and control group (P = .36). Also the 5-item World Health Organization Well-Being Index score did not differ between the sunbed and control groups (P = .19).

LIMITATIONS

For ethical reasons recruitment was limited to persons actively seeking sunbed exposure.

CONCLUSIONS

Standard use of sunbeds compliant with the European Union standard induced a transient increase of 25(OH)D levels, whereas no change in well-being was observed.

Comparison of ultraviolet A light protection standards in the United States and European Union through in vitro measurements of commercially available sunscreens

BACKGROUND

The importance of adequate ultraviolet A light (UVA) protection has become apparent in recent years. The United States and Europe have different standards for assessing UVA protection in sunscreen products.

OBJECTIVE

We sought to measure the in vitro critical wavelength (CW) and UVA protection factor (PF) of commercially available US sunscreen products and see if they meet standards set by the United States and the European Union.

METHODS

Twenty sunscreen products with sun protection factors ranging from 15 to 100+ were analyzed. Two in vitro UVA protection tests were conducted in accordance with the 2011 US Food and Drug Administration final rule and the 2012 International Organization for Standardization method for sunscreen effectiveness testing.

RESULTS

The CW of the tested sunscreens ranged from 367 to 382 nm, and the UVA PF of the products ranged from 6.1 to 32. Nineteen of 20 sunscreens (95%) met the US requirement of CW >370 nm. Eleven of 20 sunscreens (55%) met the EU desired ratio of UVA PF/SPF > 1:3.

LIMITATIONS

The study only evaluated a small number of sunscreen products.

CONCLUSION

The majority of tested sunscreens offered adequate UVA protection according to US Food and Drug Administration guidelines for broad-spectrum status, but almost half of the sunscreens tested did not pass standards set in the European Union.

Corneal stromal demarcation line after collagen cross-linking in corneal ectatic diseases: a review of the literature

Collagen cross-linking (CXL) is a relatively new conservative approach for progressive corneal ectasia, which is able to strengthen corneal tissue reforming new covalent bonds. Subjective and objective results following this method seem to be promising. In recent years, newer CXL protocols have been developed to perform more effective and less invasive procedures. The increasing diffusion of CXL in the corneal ectatic disease has increased the need to have actual indices regarding the efficacy of the treatment. Evaluation of demarcation line (DL), a transition zone between the cross-linked anterior corneal stroma and the untreated posterior corneal stroma, is considered a measurement of the depth of CXL treatment into the stroma. Some evidence in the literature emphasize that DL could be a measure of effectiveness of the CXL. On the contrary, some authors believe that the “the deeper, the better” principle is rather a simplistic approach for interpreting the clinical importance of the corneal stromal DL.

Licoricidin, an isoflavonoid isolated from Glycyrrhiza uralensis Fisher, prevents UVA-induced photoaging of human dermal fibroblasts

OBJECTIVE

Licoricidin is an isoflavonoid isolated from Glycyrrhiza uralensis Fisher. In this study, we investigated the effects of licoricidin on photoaging of UVA-irradiated human dermal fibroblasts (HDFs).

METHODS

In vitro reactive oxygen species (ROS) scavenging activity, cellular protective effect and inhibition of elastase activity was determined by Fe³⁺ -EDTA/H₂ O₂ systems, photohaemolysis and elastase activity assay, respectively. Anti-oxidative capacity of the compound was evaluated by fluorescent ELISA and 2', 7'-dichlorofluorescin-diacetate (DCF-DA) assay. The expression of protein and phosphorylation was examined using Western blot.

RESULTS

The ROS scavenging activity (OSC₅₀ ) of licoricidin was 2.77 μM. It was 3.1-fold higher than that of L-ascorbic acid. Its protective effects were confirmed in a study of ¹ O₂ -induced cellular damage to human erythrocytes. The τ₅₀ value of 10 μM of licoricidin was 71.0 min; this was markedly higher than that obtained with α-tocopherol (37.0 min). The elastase inhibitory activity of licoricidin (IC₅₀ of 61.2 μM) was 2.1-fold more potent than that of oleanolic acid. Licoricidin markedly reduced the UVA-induced intracellular ROS in a concentration-dependent manner. Western blot revealed that licoricidin attenuated the UVA-dependent induction of MMP-1 protein. Mechanistically, this appeared to be due to licoricidin-dependent inhibition of mitogen-activated protein kinases (MAPK) phosphorylation, which resulted in decreased c-Jun activation and reduced c-Jun and c-Fos expression.

CONCLUSION

Licoricidin blocks UVA-induced photoaging via ROS scavenging. This activity converges to limit the activity of MMP-1. These data suggest that licoricidin may be considered as an active ingredient in new topically applied anti-ageing formulations.

Long-term UVA eye irradiation causes decreased learning ability in mice

BACKGROUND

Long-term eye radiation with ultraviolet A (UVA) denatures the cells of the cerebral hippocampus. However, the influence on memory and learning ability in mice is not known.

METHODS

HR-1 mice were used. We irradiated the eyes or dorsal skin of the mice with UVA at a dose of 110 kJ/m(2) using an FL20SBLB-A lamp for 6, 12, and 24 months.

RESULTS

The mean escape latency in the water maze was significantly increased in the UVA-irradiated mice in comparison with that seen in the controls. In the mice in which UVA eye irradiation was performed for 24 months, the depression of memory and learning ability was remarkable. The acetylcholinesterase activity, choline acetyltransferase activity, and acetylcholine content in the brain in the UVA eye-irradiated mice were significantly less than those observed in the control mice. Furthermore, during UVA eye irradiation, the levels of β-amyloid (Aβ), γ-secretase, which produces Aβ peptide, and advanced glycation end products increased. Moreover, the effects of UVA eye irradiation increased with the duration of irradiation (or aging), and the introduction of glucose into the brain also decreased with UVA eye irradiation.

CONCLUSIONS

These results indicate that UVA eye irradiation induces a decreased memory and learning ability in mice.

Corneal cross-linking treatment of keratoconus

Keratoconus as the most common cause of ectasia is one of the leading cause of corneal transplants worldwide. The current available therapies do not modify the underlying pathogenesis of the disease, and none of the available approaches but corneal transplant hinder the ongoing ectasia. Several studies document Crosslink defect between collagen fibrils in the pathogenesis of keratoconus. Collagen cross link is a relatively new approach that with the application of the riboflavin and ultraviolet A, new covalent bands reform. Subjective and objective results following this method seem to be promising. Endothelial damage besides other deep structural injury, which is the major concern of this technique have not yet been reported, when applying the standard method.

UVA irradiation of the eye modulates the contact hypersensitivity of the skin and intestines by affecting mast cells in mice

BACKGROUND

Ultraviolet A (UVA) irradiation before allergic sensitization induces immunosuppression, but the precise mechanism remained unclear. In this study, we examined the influence of UVA irradiation of the eye on contact hypersensitivity (CHS) and the role of mast cells in CHS.

METHODS

We used two types of haptens, fluorescein isothiocyanate (FITC: a Th2 type hapten) and 4-ethoxymethylene-2-phenyl-2-oxazolin-5-one (oxazolone: a Th1 type hapten). A 300 kJ/m(2) dose of UVA irradiation was delivered to the eyes. After UVA irradiation, we sensitized abdominal shaved skin and challenged the ear epidermis and colons of these mice with each hapten.

RESULTS

After UVA irradiation, the CHS of the skin and colon were not inhibited in the FITC-sensitized mice. However, in the oxazolone-sensitized mice, only the CHS of the skin was inhibited by UVA irradiation. The inflammation of the colon became more severe after UVA irradiation. In mast cell-deficient (W/Wv) mice sensitized to FITC, the CHS was weaker than that in WT mice. Moreover, the reduction of immunosuppression in ear swelling was seen for one of the two models they used.

CONCLUSIONS

These results suggest that the mast cells induced by UVA irradiation of the eye have different roles in the epidermis and colon and have different responses to different haptens.

Evaluation of the in vitro antimicrobial properties of ultraviolet A/riboflavin mediated crosslinking on Candida albicans and Fusarium solani

AIM

To evaluate the antimicrobial properties of ultraviolet A (UVA) (365 nm)/riboflavin against Candida albicans and Fusarium solani.

METHODS

Two fungus isolates were cultured in vitro and prepared with 10-fold serial PBS dilutions of cell concentration. For each dilution of fungus suspension, the concentration (colony-forming units/mL, CFU/mL) and the inactivation ratio of fungal cells were evaluated under 4 conditions: no treatment (control), UVA (365 nm)/riboflavin, riboflavin, and UVA (365 nm).

RESULTS

The cell concentration decreased in UVA (365 nm)/riboflavin group for Candida albicans at each dilution and Fusarium solani at dilutions of 10(4), 10(3), 10(2) CFU/mL, when compared with that in control, riboflavin, and UVA (365 nm) groups (P<0.01). No difference of cell concentration was detected amongst the culture of control, riboflavin, and UVA (365 nm) groups for the two fungus. There is a negative correlation between suspension concentration (log-transformed) and the inactivation ratio in UVA (365 nm)/riboflavin group for Candida albicans and Fusarium solani (P<0.01).

CONCLUSION

According to the standard protocol of corneal collagen cross-linking, UVA (365 nm)/riboflavin combination treatment is found to moderately inactivate the viability of Candida albicans and Fusarium solani in vitro. The inactivation ratio was found to increase with the decrease of cell concentration under UVA (365 nm)/riboflavin condition.

Redox-sensitive YFP sensors for monitoring dynamic compartment-specific glutathione redox state

Intracellular redox homeostasis is crucial for many cellular functions but accurate measurements of cellular compartment-specific redox states remain technically challenging. Genetically encoded biosensors including the glutathione-specific redox-sensitive yellow fluorescent protein (rxYFP) may provide an alternative way to overcome the limitations of conventional glutathione/glutathione disulfide (GSH/GSSG) redox measurements. This study describes the use of rxYFP sensors for investigating compartment-specific steady redox state and their dynamics in response to stress in human cells. RxYFP expressed in the cytosol, nucleus, or mitochondrial matrix of HeLa cells was responsive to the intracellular redox state changes induced by reducing as well as oxidizing agents. Compartment-targeted rxYFP sensors were able to detect different steady-state redox conditions among the cytosol, nucleus, and mitochondrial matrix. These sensors expressed in human epidermal keratinocytes HEK001 responded to stress induced by ultraviolet A radiation in a dose-dependent manner. Furthermore, rxYFP sensors were able to sense dynamic and compartment-specific redox changes caused by 100 μM hydrogen peroxide (H2O2). Mitochondrial matrix-targeted rxYFP displayed a greater dynamics of oxidation in response to a H2O2 challenge than the cytosol- and nucleus-targeted sensors, largely due to a more alkaline local pH environment. These observations support the view that mitochondrial glutathione redox state is maintained and regulated independently from that of the cytosol and nucleus. Taken together, our data show the robustness of the rxYFP sensors to measure compartmental redox changes in human cells. Complementary to existing redox sensors and conventional redox measurements, compartment-targeted rxYFP sensors provide a novel tool for examining mammalian cell redox homeostasis, permitting high-resolution readout of steady glutathione state and dynamics of redox changes.

Telomere shortening in cultured human dermal fibroblasts is associated with acute photodamage induced by UVA irradiation

Introduction

Photoaging is the superposition of chronic ultraviolet (UV)-induced damage on intrinsic aging. Telomere length is a molecular marker of cell aging, and genomic instability due to telomere shortening has been linked to several aging-related diseases.

Aim

To explore the effects of different doses of ultraviolet A (UVA) on the length of telomeres in human skin fibroblasts and partly reveal the mechanism of skin photoaging initiated by UVA irradiation.

Material and methods

Primary cultured human skin fibroblasts were irradiated with different doses of UVA light. Cell viability, cell cycle phase, β-galactosidase, and the length of telomeres were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometry, cytochemical staining, and real-time polymerase chain reactions, respectively.

Results

After UVA irradiation, inhibited proliferation, S phase accumulation and increased expression of senescence-associated β-galactosidase were observed in cultured fibroblasts. Moreover, the length of telomeres in UVA-treated cells was shortened in a dose-dependent manner as compared to controls (p < 0.05).

Conclusions

These results suggest that telomere length in human dermal fibroblasts can be shortened by a single high dosage of UVA radiation, and that acute photodamage might contribute to early photoaging in human skin via rapid telomere shortening. This study potentially provides the basis for better understanding of the molecular mechanism of photoaging.