Allergic contact dermatitis is associated with significant oxidative stress

Metabolic activation of 2,4,6-trinitrotoluene; a case for ROS-induced cell damage

The explosive compound 2,4,6-trinitrotoluene (TNT) is well known as a major component of munitions. In addition to its potential carcinogenicity and mutagenicity in humans, recent reports have highlighted TNT toxicities in diverse organisms due to its occurrence in the environment. These toxic effects have been linked to the intracellular metabolism of TNT, which is generally characterised by redox cycling and the generation of noxious reactive molecules. The reactive intermediates formed, such as nitroso and hydroxylamine compounds, also interact with oxygen molecules and cellular components to cause macromolecular damage and oxidative stress. The current review aims to highlight the crucial role of TNT metabolism in mediating TNT toxicity, via increased generation of reactive oxygen species. Cellular proliferation of reactive species results in depletion of cellular antioxidant enzymes, DNA and protein adduct formation, and oxidative stress. While TNT toxicity is well known, its ability to induce oxidative stress, resulting from its reductive activation, suggests that some of its toxic effects may be caused by its reactive metabolites. Hence, further research on TNT metabolism is imperative to elucidate TNT-induced toxicities.

Antioxidative and Antimicrobial Evaluation of Bark Extracts from Common European Trees in Light of Dermal Applications

Plant species have developed effective defense strategies for colonizing diverse habitats and protecting themselves from numerous attacks from a wide range of organisms, including insects, vertebrates, fungi, and bacteria. The bark of trees in particular constitutes a number of components that protect against unwanted intruders. This review focuses on the antioxidative, dermal immunomodulatory, and antimicrobial properties of bark extracts from European common temperate trees in light of various skin pathogens, wound healing, and the maintenance of skin health. The sustainability aspect, achieved by utilizing the bark, which is considered a byproduct in the forest industry, is addressed, as are various extraction methods applied to retrieve extracts from bark.

Chitosan self-assembled polymeric nanoparticles for percutaneous delivery of betamethasone in contact dermatitis

OBJECTIVE

The study was performed with an aim to investigate the efficiency of two treatment options in experimental nickel-induced contact dermatitis (CT), with either betamethasone or chitosan cross-linked nano-encapsulated betamethasone lanoline solutions (nano-betamethasone).

METHODS

Male Wistar rats were used. The differences were compared based on lesion visual appearance, skinfold thickness, white blood cell count (WBC), erythrocyte sedimentation rate (ESR), blood serum prooxidant-antioxidant balance (thiobarbituric acid reactive substances, TBARS; supersoxide dismutase, SOD; catalase, KAT), blood cytokine profile (TNF-α, IL-1β, IL-10, and IL-4), and histological examination of affected skin.

RESULTS

All animals treated with nickel sulfate developed CT and systemic inflammatory response on day 12, which only slightly lessened, if left untreated, on day 20. The therapeutic effectiveness of nano-betamethasone was significantly far superior (p < 0.01) compared to betamethasone. Specifically, the visual appearance of lesion severity of betamethasone vs. nano-betamethasone ± SD was 1.82 ± 0.18 vs. 1.17 ± 0.24 points, skinfold thickness-2.68 ± 0.12 vs. 2.12 ± 0.10 mm, ESR-6.38 ± 0.27 vs. 5.12 ± 0.20 mm/h, WBC-8.47 ± 0.28 vs. 7.17 ± 0.24 10⁹/L, TBARS-1.09 ± 0.04 vs. 0.94 ± 0.02 µmol/L, SOD-3.38 ± 0.26 vs. 4.12 ± 0.18 r.u./L, KAT-11.54 ± 0.14 vs. 10.02 ± 0.19 mkatal/L, respectively. The nano-betamethasone formulation was also more effective (p < 0.01) in increasing anti-inflammatory cytokines level, IL-10 (8.96 ± 0.32 vs. 7.54 ± 0.52 pg/mL) and IL-4 (13.16 ± 0.45 vs. 11.43 ± 0.58 pg/mL); and decreasing in pro-inflammatory TNF-α (20.94 ± 2.30 vs. 26.98 ± 1.16 pg/mL) and IL-1β (19.35 ± 1.28 vs. 24.77 ± 1.75 pg/mL), respectively. These findings were also supported with histological examination.

CONCLUSIONS

Nano-betamethasone may be considered as a more successful transcutaneous therapy for managing contact dermatitis compared to ointments consisting of betamethasone in traditional form.

Short Overview of Some Assays for the Measurement of Antioxidant Activity of Natural Products and Their Relevance in Dermatology

Impaired systemic redox homeostasis is implicated in the onset and development of various diseases, including skin diseases. Therefore, continuous search for natural products with antioxidant bioactivities applicable in biomedicine is attractive topic of general interest. Research efforts aiming to validate antioxidant potentials of natural products has led to the development of several assays based on various test principles. Hence, understanding the advantages and limitations of various assays is important for selection of assays useful to study antioxidant and related bioactivities of natural products of biomedical interest. This review paper gives a short overview on some chemical and cellular bioassays used to estimate the antioxidant activity of chosen natural products together with a brief overview on the use of natural products with antioxidant activities as adjuvant medicinal remedies in dermatology.

Dose- and time-dependent changes in viability and IL-6, CXCL8 and CCL2 production by HaCaT-cells exposed to cobalt. Effects of high and low calcium growth conditions

Background

Sensitization requires exposure to an allergen with subsequent production of a “danger “signal. In the skin, keratinocytes are the main producers of these signals.

Objective

To compare dose- and time-effects of cobalt on the viability of and cytokine release from HaCaT cells cultured at low or high calcium.

Method

To model two separate states of differentiation of keratinocytes, HaCaT cells were cultured under low or high calcium conditions. HaCaT were exposed to different concentrations of cobalt chloride (10 μm to 5 mM) over time (30 minutes– 48 hours). Cell viability was measured with the Cell-Titer Blue Viability assay. Cytokine production was measured using a bead-based immunoassay and flow cytometry. Gene expression was quantified using qPCR. Data was analyzed by ANOVA and linear mixed model.

Results

Viability of the cells was dose- and time-dependent. A linear mixed statistical model showed that cobalt exposure induces increase in IL-6, CXCL8 and CCL2 production over time and whereas increase of IL-6 and a decrease of CCL2 was associated with increasing cobalt chloride concentrations. When comparing the cells incubated under high and low calcium conditions, the more differentiated cells in the high concentration were found to exert a stronger response in terms of IL-6 release.

Conclusions

Our data suggest that cobalt chloride triggered an alarm system in HaCaT cells, and proinflammatory cytokines/chemokines were secreted in a dose- and time-dependent manner. When high and low calcium incubations were compared, the difference was seen only for IL-6. These findings indicate that the effect of cobalt chloride on cell toxicity occurs throughout the living epidermis.

Combined Oral and Topical Application of Pumpkin (Cucurbita pepo L.) Alleviates Contact Dermatitis Associated With Depression Through Downregulation Pro-Inflammatory Cytokines

Background: Depression and contact dermatitis (CD) are considered relatively common health problems that are linked with psychological stress. The antioxidant, anti-inflammatory, and antidepressant activities of pumpkin were previously reported. Objectives: This study aimed to evaluate the efficacy of the combined topical and oral application of pumpkin fruit (Cucurbita pepo L.) extract (PE) in relieving CD associated with chronic stress-induced depression and compare it to the topical pumpkin extract alone and to the standard treatment. Materials and Methods: Forty male albino rats were exposed to chronic unpredictable mild stress (CUMS) for 4 weeks for induction of depression and then exposed to (1-fluoro-2, 4-dinitrofluorobenzene, DNFB) for 2 weeks for induction of CD. Those rats were assigned into 4 groups (n = 10 each); untreated, betamethasone-treated, PE-treated and pumpkin extract cream, and oral-treated groups. Treatments were continued for 2 weeks. All groups were compared to the negative control group (n = 10). Depression was behaviorally and biochemically confirmed. Serum and mRNA levels of pro-inflammatory cytokines, such as TNF-α, IL-6, COX-2, and iNOS, were assessed. Oxidant/antioxidant profile was assessed in the serum and skin. Histopathological and immunohistochemical assessments of affected skin samples were performed. Results: Pumpkin extract, used in this study, included a large amount of oleic acid (about 56%). The combined topical and oral administration of PE significantly reduced inflammatory and oxidative changes induced by CD and depression compared to the CD standard treatment and to the topical PE alone. PE significantly alleviated CD signs and the histopathological score (p < 0.001) mostly through the downregulation of pro-inflammatory cytokines and the upregulation of antioxidants. Conclusion: Pumpkin extract, applied topically and orally, could be an alternative and/or complementary approach for treating contact dermatitis associated with depression. Further studies on volunteer patients of contact dermatitis are recommended.

Repeated dermal application of the common preservative methylisothiazolinone triggers local inflammation, T cell influx, and prolonged mast cell-dependent tactile sensitivity in mice

Occupational exposure to toxic chemicals increases the risk of developing localized provoked vulvodynia-a prevalent, yet poorly understood, chronic condition characterized by sensitivity to touch and pressure, and accumulation of mast cells in painful tissues. Here, we topically sensitized female ND4 Swiss mice to the common household and industrial preservative methylisothiazolinone (MI) and subsequently challenged them daily with MI or acetone and olive oil vehicle on the labiar skin. MI-challenged mice developed significant, persistent tactile sensitivity and long-lasting local accumulation of mast cells alongside early, transient increases in CD4+ and CD8+ T cells, eosinophils, neutrophils, and increases in pro-inflammatory cytokines. Therapeutic administration of imatinib, a c-Kit inhibitor known to inhibit mast cell survival, led to reduced mast cell accumulation and alleviated tactile genital pain. We provide the first pre-clinical evidence of dermal MI-induced mast-cell dependent pain and lay the groundwork for detailed understanding of these intersections between MI-driven immunomodulation and chronic pain.

MCP-1 produced by keratinocytes is associated with leucocyte recruitment during elicitation of nickel-induced occupational allergic contact dermatitis

To investigate the expression profile of monocyte chemoattractant peptide-1 (MCP-1) by keratinocytes after nickel exposure and to identify its role for leucocyte migration during nickel-induced occupational allergic contact dermatitis (OACD), 26 workers diagnosed with nickel-induced OACD were enrolled. Skin biopsies from the positive nickel-challenged sites at different time points were assessed by immunohistochemistry (IHC) for MCP-1, CD68, CD45RO, and in situ hybridization (ISH) for MCP-1, using chronic periumbilical dermititis as controls. The expressions of MCP-1 in HaCaT cell culture after nickel treatment were quantified by enzyme-linked immunosorbent assay. The results showed that at positive nickel-challenged sites, strong expressions of MCP-1, both messenger RNA (mRNA) and protein, were detected in the basal keratinocytes during the early phase (24-48 h after nickel application), paralleled by the recruitment of CD68⁺ and CD45RO⁺ cells to the skin compartments. The expressions of MCP-1 declined gradually in the late phase (72-96 h after nickel application). Treatment with nickel sulfate at noncytotoxic concentrations (0.01-100 µM) induced a concentration-related elevation of MCP-1 expression by HaCaT cells compared to the untreated cells. The data indicated that a temporal expression pattern of MCP-1 produced by keratinocytes after nickel exposure was involved in the complex process of mononuclear cell infiltration during elicitation of nickel-induced OACD. Targeting MCP-1 might be a potential therapeutic strategy for OACD.

Increased risk of stroke in contact dermatitis patients: A nationwide population-based retrospective cohort study

Dermatologic diseases are not traditional risk factors of stroke, but recent studies show atopic dermatitis, psoriasis, and bullous skin disease may increase the risk of stroke and other cardiovascular diseases. No previous studies have focused on the association between contact dermatitis and stroke.We established a cohort comprised of 48,169 contact dermatitis patients newly diagnosed in 2000-2003 and 96,338 randomly selected subjects without the disorder, frequency matched by sex, age, and diagnosis year, as the comparison cohort. None of them had a history of stroke. Stroke incidence was assessed by the end of 2011 for both cohorts.The incidence stroke was 1.1-fold higher in the contact dermatitis cohort than in the comparison cohort (5.93 vs 5.37 per 1000 person-years, P < 0.01). The multivariable Cox method analyzed adjusted hazard ratios (aHRs) were 1.12 (95% confidence interval [CI], 1.05-1.19) for all stroke types and 1.12 (95% CI, 1.05-1.20) for ischemic stroke and 1.11 (95% CI, 0.94-1.30) for hemorrhagic stroke. The age-specific aHR of stroke for contact dermatitis cohort increased with age, from 1.14 (95% CI, 1.03-1.27) for 65 to 74 years; to 1.27 (95% CI, 1.15-1.42) for 75 years and older. The aHR of stroke were 1.16 (95% CI, 1.07-1.27) and 1.09 (95% CI, 1.00-1.18) for men and women, respectively.This study suggests that patients with contact dermatitis were at a modestly increased risk of stroke, significant for ischemic stroke but not for hemorrhagic stroke. Comorbidity, particularly hypertension, increased the hazard of stroke further.

Coenzyme Q10 Suppresses TNF-α-Induced Inflammatory Reaction In Vitro and Attenuates Severity of Dermatitis in Mice

Anti-oxidant coenzyme Q10 (Co-Q10) is commonly used in clinic. Recently, Co-Q10 was reported to antagonize TNF-α-induced inflammation and play a protective role in various inflammatory conditions. However, its role in dermatitis is unknown. Herein, RAW264.7 macrophage cell line was cultured with stimulation of TNF-α, and administration of Co-Q10 alleviated TNF-α-mediated inflammatory reaction in vitro. Furthermore, oxazolone-induced dermatitis mice model was established, and treatment of Co-Q10 markedly attenuated dermatitis phenotype in this mice model. Moreover, the protective role of Co-Q10 in vitro and in dermatitis was probably due to its repression on NF-κB signaling. Collectively, Co-Q10 may represent a potential molecular target for prevention and treatment of inflammatory skin diseases.

Neurotensin-based hybrid peptide's anti-inflammatory activity in murine model of a contact sensitivity response

The objective of the study was to investigate the possibility of modulation of skin inflammation by topical treatment with a novel compound: an opioid-neurotensin hybrid peptide PK20 encompassing endomorphin-2 analog and modified fragment of neurotensin (8-13). Contact sensitivity response was induced in mice by skin sensitization with dinitrofluorobenzene (DNFB) followed by topical hapten application on ears. Mice were treated locally with PK20 or pure cream 2h after the challenge with DNFB. 2 and 24h after hapten exposure, ear thickness was determined. Ears were collected for histology and homogenization. Supernatants were used for measurement of contents of cytokines and lipid peroxidation products. Treatment with PK20 reduced significantly the late phase of contact sensitivity response, which was revealed by ear thickness diminution and reduction of inflammatory cell infiltration. The average concentrations of IL-1α, MCP-1, TNF-α and thiobarbituric acid-reactive substances were significantly decreased in the ears treated with the chimera in comparison to the control cream treated ears in DNFB sensitized/DNFB challenged group. We found that PK20 topical treatment alleviates hypersensitivity responses triggered by DNFB challenge and usage of the hybrid peptide may be a novel therapeutic strategy in the treatment of chronic inflammatory diseases. However, the mechanism remains unclear and needs further investigation.