Oxidative and nitrative stress in bronchial asthma

Supersulfide formation in the sinus mucosa of chronic rhinosinusitis

Objectives

Disruption of the oxidative stress defense system is involved in developing various diseases. Sulfur compounds such as glutathione (GSH) and cysteine (CysSH) are representative antioxidants in the body. Recently, supersulfides, including reactive persulfide and polysulfide species, have gained attention as potent antioxidants regulating oxidative stress and redox signaling. However, their involvement in the pathogenesis of chronic rhinosinusitis (CRS) remains unclear.

Methods

To clarify the changes in sulfur compounds within the sinus mucosa of each CRS subtype, we measured sulfur compound levels in the sinus mucosa of control individuals (n = 9), patients with eosinophilic CRS (ECRS) (n = 13), and those with non-ECRS (nECRS) (n = 11) who underwent sinus surgery using mass spectrometry.

Results

GSH and CysSH levels were significantly reduced, and the glutathione disulfide (GSSG)/GSH ratio, an oxidative stress indicator, was increased in patients with ECRS. Despite the absence of notable variations in supersulfides, patients with ECRS and nECRS exhibited a significant reduction in glutathione trisulfide (GSSSG), which serves as the precursor for supersulfides.

Conclusions

This study is the first quantitative assessment of supersulfides in normal and inflamed sinus mucosa, suggesting that sulfur compounds contribute to the pathogenesis of CRS.

Level of Evidence

N/A.

Bronchom assuages airway hyperresponsiveness in house dust mite-induced mouse model of allergic asthma and moderates goblet cell metaplasia, sub-epithelial fibrosis along with changes in Th2 cytokines and chemokines

Background

Asthma is a common obstructive airway disease with an inflammatory etiology. The main unmet need in the management of asthma is inadequate adherence to pharmacotherapy, leading to a poorly-controlled disease state, necessitating the development of novel therapies. Bronchom is a calcio-herbal formulation, which is purported to treat chronic asthma. The objective of the current study was to examine the in-vivo efficacy of Bronchom in mouse model of allergic asthma.

Methods

Ultra high performance liquid chromatography was utilized to analyze the phytocompounds in Bronchom. Further, the in-vivo efficacy of Bronchom was evaluated in House dust mite (HDM)-induced allergic asthma in mice. Mice were challenged with aerosolized methacholine to assess airway hyperresponsiveness. Subsequently, inflammatory cell influx was evaluated in bronchoalveolar lavage fluid (BALF) followed by lung histology, wherein airway remodeling features were studied. Simultaneously, the levels of Th2 cytokines and chemokines in the BALF was also evaluated. Additionally, the mRNA expression of pro-inflammatory and Th2 cytokines was also assessed in the lung along with the oxidative stress markers.

Results

Phytocompounds present in Bronchom included, gallic acid, protocatechuic acid, methyl gallate, rosmarinic acid, glycyrrhizin, eugenol, 6-gingerol and piperine. Bronchom effectively suppressed HDM-induced airway hyperresponsiveness along with the influx of leukocytes in the BALF. Additionally, Bronchom reduced the infiltration of inflammatory cells in the lung and it also ameliorated goblet cell metaplasia, sub-epithelial fibrosis and increase in α-smooth muscle actin. Bronchom decreased Th2 cytokines (IL-4 and IL-5) and chemokines (Eotaxin and IP-10) in the BALF. Likewise, it could also suppress the mRNA expression of pro-inflammatory cytokines (TNF-α, IFN-γ, IL-6 and IL-33), and IL-13. Moreover, Bronchom restored the HDM-induced diminution of endogenous anti-oxidants (GSH and SOD) and the increase in pro-oxidants (GSSG and MDA). Furthermore, Bronchom could also decrease the nitrosative stress by lowering the observed increase in nitrite levels.

Conclusion

Taken together, the results of the present study data convincingly demonstrate that Bronchom exhibits pharmacological effects in an animal model of allergic asthma. Bronchom mitigated airway hyperresponsiveness, inflammation and airway remodeling evoked by a clinically relevant allergen and accordingly it possesses therapeutic potential for the treatment of asthma.

Hispidulin Alleviates Mast Cell-Mediated Allergic Airway Inflammation through FcεR1 and Nrf2/HO-1 Signaling Pathway

Allergic asthma is a type 2 immune-response-mediated chronic respiratory disease. Mast cell activation influences the pathogenesis and exacerbation of allergic asthma. Therefore, the development of mast cell-targeting pharmacotherapy is important for managing allergic airway inflammation. We investigated the efficacy of hispidulin (HPD), natural flavone, in a mast-cell-mediated ovalbumin (OVA)-induced allergic airway inflammation model. HPD alleviated symptoms of allergic asthma and decreased the levels of immunoglobulin (Ig) E, type 2 inflammation, immune cell infiltration, and mast cell activation in the lung. Furthermore, in vivo analysis confirmed the efficacy of HPD through the evaluation of IgE-mediated allergic responses in a mast cell line. HPD treatment inhibited mast cell degranulation through inhibition of the FcεR1 signaling pathway and suppressed the expression of inflammatory cytokines (TNF-α, IL-4, IL-6, and IL-13) through suppression of the NF-κB signaling pathway. The antioxidant effects of HPD in activated mast cells were identified through modulation of antioxidant enzymes and the Nrf2/HO-1 signaling pathway. In conclusion, HPD may be a potential therapeutic candidate for allergic airway inflammation of asthma and acts by suppressing mast cell activation and oxidative stress.

Preparation and in vivo evaluation of nano sized cubosomal dispersion loaded with Ruta graveolens extracts as a novel approach to reduce asthma-mediated lung inflammation

Asthma is a chronic disease affecting people of all ages. Asthma medications are associated with adverse effects restricting their long-term usage, demanding newer alternative therapies. This study aimed to investigate the anti-asthmatic properties of Ruta graveolens extract and its prepared nano-cubosomal dispersion (Ruta-ND). Firstly, the R. graveolens methanolic extract exhibited higher anti-inflammatory activity on Lipopolysaccharide (LPS)-activated BEAS-2B cells. To ensure best bioavailability and hence best cellular uptake, R. graveolens extract was loaded in nano-cubosomal dispersion (ND). Then, the anti-asthmatic effects of Ruta extract and ND were simultaneously evaluated in rats' model with ovalbumin-induced allergic asthma. R. graveolens extract and Ruta-ND subsided asthma score and improved lung function by restoring FEV1/FVC ratio to the expected values in control rats. Also, it showed strong antioxidant and anti-inflammatory activities manifested by lowering levels of malondialdehyde (MDA), IL-4, IL-7, TGF-β, and Ig-E, and increasing levels of superoxide dismutase (SOD) and INF-γ in bronchoalveolar lavage fluid. Our research findings also indicate autophagy induction and apoptosis inhibition by Ruta extract and Ruta-ND. Finally, the HPLC MS/MS phytochemical profiling of R. graveolens extract evident production of various alkaloids, flavonoids, coumarins, and other phenolics with reported pharmacological properties corresponding to/emphasize our study findings. In conclusion, R. graveolens exhibited promise in managing Ova-induced allergic asthma and could be developed as an alternative anti-allergic asthma drug.

Particulate matter-mediated oxidative stress induces airway inflammation and pulmonary dysfunction through TXNIP/NF-κB and modulation of the SIRT1-mediated p53 and TGF-β/Smad3 pathways in mice

Exposure to particulate matter is currently recognized as a serious aggravating factor of respiratory diseases. In this study, we investigated the effects of particulate matter (PM) on the respiratory system in BALB/c mice and NCI-H292 cells. PM (0, 2.5, 5 and 20 mg/kg) was administered to mice by intra-tracheal instillation for 7 days. After a 7 day-repeated treatment of PM, we evaluated inflammatory cytokines/cell counts in bronchoalveolar lavage fluid (BALF) and conducted pulmonary histology and functional test. We also investigated the role of TXNIP/NF-κB and SIRT1-mediated p53 and TGF-β/Smad3 pathways in PM-induced airway inflammation and pulmonary dysfunction. PM caused a significant increase in pro-inflammatory cytokines, inflammatory cell counts in bronchoalveolar lavage fluid. PM-mediated oxidative stress down-regulated thioredoxin-1 and up-regulated thioredoxin-interacting protein and activation of nuclear factor-kappa B in the lung tissue and PM-treated NCI-H292 cells. PM suppressed sirtuin1 protein levels and increased p53 acetylation in PM-exposed mice and PM-treated NCI-H292 cells. In addition, PM caused inflammatory cell infiltration and the thickening of alveolar walls by exacerbating the inflammatory response in the lung tissue. PM increased levels of transforming growth factor-β, phosphorylation of Smad3 and activation of α-smooth muscle actin, and collagen type1A2 in PM-exposed mice and PM-treated NCI-H292 cells. In pulmonary function tests, PM exposure impaired pulmonary function resembling pulmonary fibrosis, characterized by increased resistance and elastance of the respiratory system, and resistance, elastance, and damping of lung tissues, whereas decreased compliance of the respiratory system, forced expired volume and forced vital capacity. Overall, PM-mediated oxidative stress caused airway inflammation and pulmonary dysfunction with pulmonary fibrosis via TXNIP pathway/NF-κB activation and modulation of the SIRT1-mediated TGF-β/Smad3 pathways. The results of this study can provide fundamental data on the potential adverse effects and underlying mechanism of pulmonary fibrosis caused by PM exposure as a public health concern. Due to the potential toxicity of PM, people with respiratory disease must be careful with PM exposure.

CYP27A1-27-hydroxycholesterol axis in the respiratory system contributes to house dust mite-induced allergic airway inflammation

BACKGROUND

27-Hydroxycholesterol (27-HC) derived from sterol 27-hydroxylase (CYP27A1) has pro-inflammatory biological activity and is associated with oxidative stress and chronic inflammation in COPD. However, the role of regulation of CYP27A1- 27-HC axis in asthma is unclear. This study aimed to elucidate the contribution of the axis to the pathophysiology of asthma.

METHODS

House dust mite (HDM) extract was intranasally administered to C57BL/6 mice and the expression of CYP27A1 in the airways was analyzed by immunostaining. The effect of pre-treatment with PBS or CYP27A1 inhibitors on the cell fraction in the bronchoalveolar lavage fluid (BALF) was analyzed in the murine model. In vitro, BEAS-2B cells were treated with HDM and the levels of CYP27A1 expression were examined. Furthermore, the effect of 27-HC on the expressions of E-cadherin and ZO-1 in the cells was analyzed. The amounts of RANTES and eotaxin from the 27-HC-treated cells were analyzed by ELISA.

RESULTS

The administration of HDM increased the expression of CYP27A1 in the airways of mice as well as the number of eosinophils in the BALF. CYP27A1 inhibitors ameliorated the HDM-induced increase in the number of eosinophils in the BALF. Treatment with HDM increased the expression of CYP27A1 in BEAS-2B cells. The administration of 27-HC to BEAS-2B cells suppressed the expression of E-cadherin and ZO-1, and augmented the production of RANTES and eotaxin.

CONCLUSIONS

The results of this study suggest that aeroallergen could enhance the induction of CYP27A1, leading to allergic airway inflammation and disruption of the airway epithelial tight junction through 27-HC production.

Direct assessment of nitrative stress in lipid environments: Applications of a designer lipid-based biosensor for peroxynitrite

Lipid membranes and lipid-rich organelles are targets of peroxynitrite (ONOO-), a highly reactive species generated under nitrative stress. We report a membrane-localized phospholipid (DPPC-TC-ONOO-) that allows the detection of ONOO- in diverse lipid environments: biomimetic vesicles, mammalian cell compartments, and within the lung lining. DPPC-TC-ONOO- and POPC self-assemble to membrane vesicles that fluorogenically and selectively respond to ONOO-. DPPC-TC-ONOO-, delivered through lipid nanoparticles, allowed for ONOO- detection in the endoplasmic reticulum upon cytokine-induced nitrative stress in live mammalian cells. It also responded to ONOO- within lung tissue murine models upon acute lung injury. We observed nitrative stress around bronchioles in precision cut lung slices exposed to nitrogen mustard and in pulmonary macrophages following intratracheal bleomycin challenge. Results showed that DPPC-TC-ONOO- functions specifically toward iNOS, a key enzyme modulating nitrative stress, and offers significant advantages over its hydrophilic analog in terms of localization and signal generation.

Peripheral neutrophils and oxidative stress-associated molecules for predicting the severity of asthma: a cross-sectional study based on multidimensional assessment

Objectives

This study aims to explore the relationship between the severity of asthma and neutrophils and related oxidative stress-associated molecules in peripheral blood and induced sputum.

Methods

A total of 67 subjects were included in this study, namely, 25 patients with severe asthma and 42 patients with non-severe asthma. Clinical data, induced sputum and peripheral blood were collected. Lung function and molecules related to oxidative stress in induced sputum and peripheral blood of asthma patients were detected. The relationship between neutrophils and asthma severity was analyzed. HDAC2 mRNA and protein expression levels and HDAC2 activity were also analyzed. Multivariate logistic regression was performed to select statistically significant variables.

Results

The absolute value of neutrophils and percentage of neutrophils were higher in the severe asthma patients. These two values were used to predict the severity of asthma by ROC analysis, with the best cutoff values being 4.55 × 109/L (sensitivity 83.3%, specificity 64.0%) and 55.15% (sensitivity 54.8%, specificity 88.0%). The ROS concentration of neutrophils in the induced sputum samples and the 8-iso-PGF2α concentration in the peripheral blood samples were higher in the severe asthma group (P = 0.012; P = 0.044), whereas there was reduced HDAC2 protein activity in PBMCs (P < 0.001). A logistic equation and a nomogram were created to give a precise prediction of disease severity.

Conclusion

Oxidative stress is increased in severe asthma patients. Peripheral blood neutrophils and 8-iso-PGF2α can be used as biomarkers to predict the severity of asthma. A prediction model was created for evaluating asthma severity.

Synergistic effect of nickel and temperature on gene expression, multiple stress markers, and depuration: an acute toxicity in fish

Aquatic animals are prone to extinction due to metal pollution and global climate change. Even though the fish and their products are also unsafe for human consumption, their exports have been rejected due to inorganic and organic contaminants. Nickel (Ni) is a metal that induces toxicity and accumulates in the aquatic ecosystem, posing health threats to humans, animals, and fish. In light of the above, our present investigation aimed to determine the median lethal concentration (96 h-LC50) of nickel alone and concurrent with high temperature (34 °C) (Ni + T) using static non-renewable bioassay toxicity test in Pangasianodon hypophthalmus. The groups treated under exposure to Ni reared under control condition (25-28.9 °C) and Ni + T exposure group reread under 34 °C. In this study, chose the definitive dose of Ni and Ni + T as 17, 18, 19, and 20 mg L-1 after the range finding test. The median lethal concentration of Ni and Ni + T was determined as 19.38 and 18.75 mg L-1, respectively at 96 h. Oxidative stress viz. catalase (CAT), superoxide dismutase (SOD), glutathione-s-transferase (GST), and glutathione peroxidase (GPx) in the liver, gill, and kidney were noticeably elevated with Ni and Ni + T during 96 h. Whereas, the CAT, GPx, and SOD gene expressions were significantly upregulated with Ni and Ni + T. Trilox equivalent anti-oxidant capacity (TEAC), cupric reducing anti-oxidant capacity (CUPRIC), ferric reducing ability of plasma (FRAP), ethoxy resorufin-O-deethylase (EROD), and acetylcholine esterase (AChE) were reduced due to exposure to Ni and Ni + T. Cellular metabolic stress and lipid peroxidation were highly affected due to Ni and Ni + T exposure. The immunological status, as indicated by total protein, albumin, globulin, A:G ratio, and nitro blue tetrazolium chloride (NBT), was severely affected by the toxicity of Ni and Ni + T. Moreover, the gene expression of interleukin (IL), tumor necrosis factor (TNFα), toll-like receptor (TLR), and total immunoglobulin (Ig) was remarkably downregulated following exposure to Ni and Ni + T. HSP 70, iNOS expression, ATPase, Na + /K + -ATPase, cortisol, and blood glucose was significantly elevated with Ni and Ni + T in P. hypophthalmus. The bioaccumulation of Ni in fish tissues and experimental water was determined. The kidney and liver tissues were highly accumulated with Ni, whereas DNA damage was reported in gill tissue. Interestingly, depuration study revealed that at the 28th day, the Ni bioaccumulation was below the maximum residue limit (MRL) level. Therefore, the present study revealed that Ni and Ni + T led to dysfunctional gene and metabolic regulation affecting physiology and genotoxicity. The bioaccumulation and depuration results also indicate higher residual occurrence of Ni in water and aquatic organisms for longer periods.

Agonists and hydrogen peroxide mediate hyperoxidation of β2-adrenergic receptor in airway epithelial cells: Implications for tachyphylaxis to β2-agonists in constrictive airway disorders

Asthma and other airway obstructive disorders are characterized by heightened inflammation and excessive airway epithelial cell reactive oxygen species (ROS), which give rise to a highly oxidative environment. After decades of use, β2-adrenergic receptor (β2AR) agonists remain at the forefront of treatment options for asthma, however, chronic use of β2-agonists leads to tachyphylaxis to the bronchorelaxant effects, a phenomenon that remains mechanistically unexplained. We have previously demonstrated that β2AR agonism increases ROS generation in airway epithelial cells, which upholds proper receptor function via feedback oxidation of β2AR cysteine thiolates to Cys-S-sulfenic acids (Cys-SOH). Our previous results also demonstrate that prevention of normal redox cycling of this post-translational oxi-modification back to the thiol prevents proper receptor function. Given that Cys-S-sulfenic acids can be irreversibly overoxidized to Cys-S-sulfinic (Cys-SO2H) or S-sulfonic (Cys-SO3H) acids, which are incapable of further participation in redox reactions, we hypothesized that β2-agonist tachyphylaxis may be explained by hyperoxidation of β2AR to S-sulfinic acids. Here, using airway epithelial cell lines and primary small airway epithelial cells from healthy and asthma-diseased donors, we show that β2AR agonism generates H2O2 in a receptor and NAPDH oxidase-dependent manner. We also demonstrate that acute and chronic receptor agonism can facilitate β2AR S-sulfination, and that millimolar H2O2 concentrations are deleterious to β2AR-mediated cAMP formation, an effect that can be rescued to a degree in the presence of the cysteine-donating antioxidant N-acetyl-L-cysteine. Our results reveal that the oxidative state of β2AR may contribute to receptor functionality and may, at least in part, explain β2-agonist tachyphylaxis.

Effects of Nigella sativa Oil Fractions on Reactive Oxygen Species and Chemokine Expression in Airway Smooth Muscle Cells

BACKGROUND

many previous studies have demonstrated the therapeutic potential of N. sativa total oil fractions, neutral lipids (NLs), glycolipids (GLs), phospholipids (PLs), and unsaponifiable (IS) in asthma patients. We therefore tested its effect on airway smooth muscle (ASM) cells by observing its ability to regulate the production of glucocorticoid (GC)-insensitive chemokines in cells treated with TNF-α/IFN-γ, and its antioxidative and reactive oxygen species (ROS) scavenging properties.

MATERIALS AND METHODS

the cytotoxicity of N. sativa oil fractions was assessed using an MTT assay. ASM cells were treated with TNF-α/IFN-γ for 24 h in the presence of different concentrations of N. sativa oil fractions. An ELISA assay was used to determine the effect of N. sativa oil fractions on chemokine production (CCL5, CXCL-10, and CXCL-8). The scavenging effect of N. sativa oil fractions was evaluated on three reactive oxygen species (ROS), O₂•^-, OH•, and H₂O₂.

RESULTS

our results show that different N. sativa oil fractions used at 25 and 50 µg/mL did not affect cell viability. All fractions of N. sativa oil inhibited chemokines in a concentration-dependent manner. Interestingly, the total oil fraction showed the most significant effect of chemokine inhibition, and had the highest percentage of ROS scavenging effect.

CONCLUSION

these results suggest that N. sativa oil modulates the proinflammatory actions of human ASM cells by inhibiting the production of GC-insensitive chemokines.

Neutrophil-lymphocyte ratios in blood to distinguish children with asthma exacerbation from healthy subjects

OBJECTIVE

Airway inflammation is a prominent feature of asthma and may play an important role in disease pathophysiology. Despite the increasing incidence of asthma worldwide, reliable diagnostic biomarkers are lacking and widely lead to asthma misdiagnosis. Neutrophil-lymphocyte ratio (NLR) is a biomarker of systemic inflammation, in addition to NLR-alanine aminotransferase ratio (NAR) and NLR-albumin ratio (NBR). The aim of this study was to evaluate associations of NLR, NAR, and NBR with diagnosis of childhood asthma to determine if they can aid clinical childhood asthma diagnosis.

METHODS

This retrospective case-control study included 89 children with asthma and 53 healthy children from the Wuxi Children's Hospital affiliated with Nanjing Medical University. We applied various statistical tests to the dataset: Mann-Whitney U test to compare characteristics of the case and control groups; chi-squared test to compare categorical variables; Kruskal-Wallis test to compare statistical differences of asthma indicators among groups; receiver operating characteristic (ROC) curves to assess the diagnostic value of indices; and Spearman correlation analysis to evaluate relationships between NLR and lactate dehydrogenase, albumin, aspartate transaminase, and alanine transaminase levels.

RESULTS

Compared with controls, the asthma case group had significantly higher white blood cell (p < 0.01), neutrophil, lactate dehydrogenase, C-reactive protein, and NLR levels (p < 0.01) and significantly lower lymphocyte (p = 0.001), platelet (p = 0.039), and albumin levels (p = 0.04). We determined optimal cutoff levels for several metrics: 1.723 for NLR, with sensitivity of 0.73 and specificity of 0.906; 0.135 for NAR, with sensitivity of 0.685 and specificity of 0.887; and 0.045 for NBR, with sensitivity of 0.674 and specificity of 0.906. The areas under the curve (AUCs) were 0.824 for NLR, 0.788 for NAR, 0.818 for NBR, and 0.83 for the combination of NLR + NAR + NBR.

CONCLUSION

The combination of NLR, NAR, and NBR biomarkers distinguished asthmatic ones suffering from exacerbation of the condition from healthy children. Thus, our results indicate NLR + NAR + NBR could be used as a clinical biomarker for asthma in children.

Caesalpinia sappan Linn. Ameliorates Allergic Nasal Inflammation by Upregulating the Keap1/Nrf2/HO-1 Pathway in an Allergic Rhinitis Mouse Model and Nasal Epithelial Cells

Allergic rhinitis (AR) is a common upper-airway inflammatory disease of the nasal mucosa caused by immunoglobulin (IgE)-mediated inflammation. AR causes various painful clinical symptoms of the nasal mucosa that worsen the quality of daily life, necessitating the urgent development of therapeutic agents. Herein, we investigated the effects of Caesalpinia sappan Linn. heartwood water extract (CSLW), which has anti-inflammatory and antioxidant properties, on AR-related inflammatory responses. We examined the anti-inflammatory and anti-allergic effects of CSLW in ovalbumin (OVA)-induced AR mice and in primary human nasal epithelial cells (HNEpCs). Administration of CSLW mitigated allergic nasal symptoms in AR mice, decreased total immune cell and eosinophil counts in nasal lavage fluid, and significantly reduced serum levels of OVA-specific IgE, histamine, and Th2 inflammation-related cytokines. CSLW also inhibited the infiltration of several inflammatory and goblet cells, thereby ameliorating OVA-induced thickening of the nasal mucosa tissue. We found that CSLW treatment significantly reduced infiltration of eosinophils and production of periostin, MUC5AC, and intracellular reactive oxygen species through the Keap1/Nrf2/HO-1 pathway in HNEpCs. Thus, our findings strongly indicate that CSLW is a potent therapeutic agent for AR and can improve the daily life of patients by controlling the allergic inflammatory reaction of the nasal epithelium.

Phthalate Exposure and Oxidative/Nitrosative Stress in Childhood Asthma: A Nested Case-Control Study with Propensity Score Matching

Whether low-dose phthalate exposure triggers asthma among children, and its underlying mechanisms, remain debatable. Here, we evaluated the individual and mixed effects of low-dose phthalate exposure on children with asthma and five (oxidative/nitrosative stress/lipid peroxidation) mechanistic biomarkers—8-hydroxy-2′-deoxyguanosine (8-OHdG), 8-nitroguanine (8-NO₂Gua), 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA), 8-isoprostaglandin F2α (8-isoPF2α), and malondialdehyde (MDA)—using a propensity score-matched case-control study (case vs. control = 41 vs. 111). The median monobenzyl phthalate (MBzP) concentrations in the case group were significantly higher than those in the control group (3.94 vs. 2.52 ng/mL, p = 0.02), indicating that dust could be an important source. After adjustment for confounders, the associations of high monomethyl phthalate (MMP) (75th percentile) with 8-NO₂Gua (adjusted odds ratio (aOR): 2.66, 95% confidence interval (CI): 1.03–6.92) and 8-isoPF2α (aOR: 4.04, 95% CI: 1.51–10.8) and the associations of mono-iso-butyl phthalate (MiBP) with 8-isoPF2α (aOR: 2.96, 95% CI: 1.13–7.79) were observed. Weighted quantile sum regression revealed that MBzP contributed more than half of the association (56.8%), followed by MiBP (26.6%) and mono-iso-nonyl phthalate (MiNP) (8.77%). Our findings supported the adjuvant effect of phthalates in enhancing the immune system response.

AllergoOncology: Role of immune cells and immune proteins

Background

Immune cells and immune proteins play a pivotal role in host responses to pathogens, allergens and cancer. Understanding the crosstalk between allergic response and cancer, immune surveillance, immunomodulation, role of immunoglobulin E (IgE)‐mediated functions and help to develop novel therapeutic strategies. Allergy and oncology show two opposite scenarios: whereas immune tolerance is desired in allergy, it is detrimental in cancer.

Aim

The current review provides an update on the role of immune cells and immune proteins in allergy and cancer fields.

Methods

Authors investigated the role of relevant immunological markers and the correlation with cancer progression or cancer suppression.

Results

Activated immune cells such as macrophages ‘M1’, dendritic cells (DCs), innate lymphoid cells (ILC2), NK cells, Th1, follicular T helper cells (TFH), TCD8+, B lymphocytes and eosinophils have inhibitory effects on tumourigenesis, while tolerogenic cells such as macrophages ‘M2,’ tolerogenic DCs, ILC3, T and B regulatory lymphocytes appear to favour carcinogenesis. Mastocytes and alarmins can have both effects. RIgE antibodies and CCCL5 chemokine have an anticancer role, whereas IgG4, free light chains, Il‐10, TGF‐β, lipocalin‐2, CCL1 chemokine promote cancer progression. Fundamental is also the contribution of epigenetic changes regulated by the microRNA in cancer progression.

Conclusion

This knowledge represents the key to developing new anticancer therapies.

IL-33 regulates M1/M2 chemokine expression via mitochondrial redox-related mitophagy in human monocytes

Interleukin (IL)-33 is an epithelial-derived cytokine that enhances T helper (Th) 2 responses. Allergens and other agents induce IL-33 in asthma. Excessive production of reactive oxygen species (ROS) leads to airway inflammation. Mitophagy is the selective degradation of mitochondria by autophagy and often occurs in defective mitochondria, followed by ROS production. In the present study, we examined the effects of IL-33 on ROS production and mitophagy in human monocytes, and the detailed mechanisms were investigated. Human monocyte cell line THP-1 was pretreated with different concentrations of IL-33. ROS production was measured by flow cytometry. Mitochondrial involvement and the mitophagy and intercellular pathway activation were evaluated by quantitative real-time PCR, western blotting, and confocal microscopy, and cytokine/chemokine concentrations were detected by ELISA. The data showed that IL-33 alone could induce ROS expression in THP-1 cells. The expression of complex II and V mRNA was increased in the presence of IL-33. The mitophagy-related proteins PINK1, Parkin, and LC3 were regulated by IL-33 through the AMPK pathway. IL-33 significantly decreased M1-related cytokines CXCL-10 and TNF-α production and significantly increased M2-related cytokine CCL-22 production. In conclusion, IL-33 induces ROS production and subsequently influences mitophagy through AMPK activation, altering the macrophage-polarization phenotype of monocytes.

IL-25 Induced ROS-Mediated M2 Macrophage Polarization via AMPK-Associated Mitophagy

Interleukin (IL)-25 is a cytokine released by airway epithelial cells responding to pathogens. Excessive production of reactive oxygen species (ROS) leads to airway inflammation and remodeling in asthma. Mitochondria are the major source of ROS. After stress, defective mitochondria often undergo selective degradation, known as mitophagy. In this study, we examined the effects of IL-25 on ROS production and mitophagy and investigated the underlying mechanisms. The human monocyte cell line was pretreated with IL-25 at different time points. ROS production was measured by flow cytometry. The involvement of mitochondrial activity in the effects of IL-25 on ROS production and subsequent mitophagy was evaluated by enzyme-linked immunosorbent assay, Western blotting, and confocal microscopy. IL-25 stimulation alone induced ROS production and was suppressed by N-acetylcysteine, vitamin C, antimycin A, and MitoTEMPO. The activity of mitochondrial complex I and complex II/III and the levels of p-AMPK and the mitophagy-related proteins were increased by IL-25 stimulation. The CCL-22 secretion was increased by IL-25 stimulation and suppressed by mitophagy inhibitor treatment and PINK1 knockdown. The Th2-like cytokine IL-25 can induce ROS production, increase mitochondrial respiratory chain complex activity, subsequently activate AMPK, and induce mitophagy to stimulate M2 macrophage polarization in monocytes.

The nitroxide/antioxidant 3-carbamoyl proxyl attenuates disease severity in murine models of severe asthma

Asthma is characterized by airway inflammation, hyper-responsiveness, symptoms of dyspnea, wheezing and coughing. In most patients, asthma is well controlled using inhaled corticosteroids and bronchodilators. A minority of patients with asthma develop severe disease, which is frequently only partially responsive or even resistant to treatment with corticosteroids. Severe refractory asthma is associated with structural changes in the airways, termed "airway remodeling", and/or with neutrophilic rather than eosinophilic airway inflammation. While oxidative stress plays an important role in the pathophysiology of asthma, cyclic nitroxide stable radicals, which are unique and efficient catalytic antioxidants, effectively protect against oxidative injury. We have demonstrated that the nitroxide 3-carbamoyl proxyl (3-CP) attenuates airway inflammation and hyperresponsiveness in allergic asthma as well as bleomycin-induced fibrosis both using murine models, most probably through modulation of oxidative stress. The present study evaluates the effect of 3-CP on airway inflammation and remodeling using two murine models of severe asthma where mice are sensitized and challenged either by ovalbumin (OVA) or by house dust mite (HDM). 3-CP was orally administered during the entire period of the experiment or during the challenge period alone where its effect was compared to that of dexamethasone. The induced increase by OVA and by HDM of BALf cell counts, airway hyperresponsiveness, fibrosis, transforming growth factor-beta (TGF-β) levels in BALf and protein nitration levels of the lung tissue was significantly reduced by 3-CP. The effect of 3-CP, using two different murine models of severe asthma, is associated at least partially with attenuation of oxidative stress and with TGF-β expression in the lungs. The results of this study suggest a potential use of 3-CP as a novel therapeutic agent in different forms of severe asthma.

Cimicifugae Rhizoma Extract Attenuates Oxidative Stress and Airway Inflammation via the Upregulation of Nrf2/HO-1/NQO1 and Downregulation of NF-κB Phosphorylation in Ovalbumin-Induced Asthma

Cimicifugae Rhizoma has been used as a medicinal herb for fever, pain, and inflammation in East Asia. We conducted this study because the effect of Cimicifugae Rhizoma extract (CRE) on allergic asthma has not yet been evaluated. To induce allergic airway inflammation, we intraperitoneally injected ovalbumin (OVA) mixed with aluminum hydroxide into mice twice at intervals of 2 weeks (Days 0 and 14) and then inhaled them thrice with 1% OVA solution using a nebulizer (Days 21 to 23). CRE (30 and 100 mg/kg) was administered orally daily for 6 days (Days 18 to 23). The mice showed remarkable reduction in allergic inflammation at 100 mg/kg of CRE, as evidenced by decreased inflammatory cell counts, pro-inflammatory cytokine levels, OVA-specific immunoglobulin E level, airway hyperresponsiveness, and production of mucus. Additionally, these effects were involved with the enhancement of heme oxygenase-1 (HO-1), NAD(P)H: quinone oxidoreductase (NQO1), and nuclear factor erythroid 2-related factor 2 (Nrf2) expression and reduction of nuclear factor-κB (NF-κB) phosphorylation and matrix metalloproteinase-9 expression. Our findings indicated that CRE effectively protected against OVA-induced inflammation and oxidative stress via upregulation of the Nrf2/HO-1/NQO1 signaling and downregulation of NF-κB phosphorylation in asthma caused by OVA.

Nickel nanoparticles induce hepatotoxicity via oxidative and nitrative stress-mediated apoptosis and inflammation

Nickel nanoparticles (Ni NPs) are utilized extensively in various industrial applications. However, there are increasing concerns about potential exposure to Ni NPs and consequent health effects. The aim of this study was to assess Ni NPs-induced liver toxicity in Sprague Dawley rats. Twenty-five rats were exposed to Ni NPs via intraperitoneal injection at doses of 15, 30, and 45 mg/kg per body weight for 28 days. Results from ICP-MS analysis showed an increase in the concentration of Ni NPs in a dose-dependent manner. The liver dysfunction was indicated by considerable production of ALT, AST, ALP, LDH, and TB in Ni NPs-treated rats. Histological examination demonstrated liver injuries (inflammatory cells, congestion, necrosis, and pyknosis) in exposed rats with dose-dependent severity of pathologies by semi-quantitative histograding system. To explore the toxicological pathways, we examined oxidative stress biomarkers and detected Ni NPs significantly elevated the levels of MDA and LPO while decreasing the levels of CAT and GSH. All the changes in biomarkers were recorded in a dose-dependent relationship. In addition, we found upregulated NF-kβ indicating activation of inflammatory cytokines. ELISA results of serum revealed a remarkable increase of nitrative stress markers (iNOS and NO), ATPase activity, inflammatory cytokine (IL-6, IL-1β, and TNF-α), and apoptotic mediators (caspase-3 and caspase-9) in Ni NPs-treated groups than the control. In summary, the result of this study provided evidence of hepatotoxicity of Ni NPs and insightful information about the involved toxic pathways, which will help in health risk assessment and management, related preventive measures for the use of Ni-NPs materials.

Tempol differently affects cellular redox changes and antioxidant enzymes in various lung-related cells

Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl) is a potential redox agent in cells. The present study investigated changes in cellular reactive oxygen species (ROS) and glutathione (GSH) levels and in antioxidant enzymes, in Tempol-treated Calu-6 and A549 lung cancer cells, normal lung WI-38 VA-13 cells, and primary pulmonary fibroblasts. Results demonstrated that Tempol (0.5–4 mM) either increased or decreased general ROS levels in lung cancer and normal cells at 48 h and specifically increased O₂^•− levels in these cells. In addition, Tempol differentially altered the expression and activity of antioxidant enzymes such as superoxide dismutase, catalase, and thioredoxin reductase1 (TrxR1) in A549, Calu-6, and WI-38 VA-13 cells. In particular, Tempol treatment increased TrxR1 protein levels in these cells. Tempol at 1 mM inhibited the growth of lung cancer and normal cells by about 50% at 48 h but also significantly induced cell death, as evidenced by annexin V-positive cells. Furthermore, down-regulation of TrxR1 by siRNA had some effect on ROS levels as well as cell growth inhibition and death in Tempol-treated or -untreated lung cells. In addition, some doses of Tempol significantly increased the numbers of GSH-depleted cells in both cancer cells and normal cells at 48 h. In conclusion, Tempol differentially increased or decreased levels of ROS and various antioxidant enzymes in lung cancer and normal cells, and induced growth inhibition and death in all lung cells along with an increase in O₂^•− levels and GSH depletion.

The VICTORY (Investigation of Inflammacheck to Measure Exhaled Breath Condensate Hydrogen Peroxide in Respiratory Conditions) Study: Protocol for a Cross-sectional Observational Study

Background

More than 7% of the world’s population is living with a chronic respiratory condition. In the United Kingdom, lung disease affects approximately 1 in 5 people, resulting in over 700,000 hospital admissions each year. People with respiratory conditions have several symptoms and can require multiple health care visits and investigations before a diagnosis is made. The tests available can be difficult to perform, especially if a person is symptomatic, leading to poor quality results. A new, easy-to-perform, point-of-care test that can be performed in any health care setting and that can differentiate between various respiratory conditions would have a significant, beneficial impact on the ability to diagnose respiratory diseases.

Objective

The objective of this study is to use a new handheld device (Inflammacheck) in different respiratory conditions to measure the exhaled breath condensate hydrogen peroxide (EBC H₂O₂) and compare these results with those of healthy controls and with each other. This study also aims to determine whether the device can measure other parameters, including breath humidity, breath temperature, breath flow dynamics, and end tidal carbon dioxide.

Methods

We will perform a single-visit, cross-sectional observational study of EBC H₂O₂ levels, as measured by Inflammacheck, in people with respiratory disease and volunteers with no known lung disease. Participants with a confirmed diagnosis of asthma, chronic obstructive pulmonary disease, lung cancer, bronchiectasis, pneumonia, breathing pattern disorder, and interstitial lung disease as well as volunteers with no history of lung disease will be asked to breathe into the Inflammacheck device to record their breath sample.

Results

The results from this study will be available in 2022, in anticipation of COVID-19–related delays.

Conclusions

This study will investigate the EBC H₂O₂, as well as other exhaled breath parameters, for use as a future diagnostic tool.

Tocotrienols Activate Nrf2 Nuclear Translocation and Increase the Antioxidant- Related Hepatoprotective Mechanism in Mice Liver

BACKGROUND

The most common preparation of tocotrienols is the Tocotrienol-Rich Fraction (TRF). This study aimed to investigate whether TRF induced liver Nrf2 nuclear translocation and influenced the expression of Nrf2-regulated genes.

METHODS

In the Nrf2 induction study, mice were divided into control, 2000 mg/kg TRF and diethyl maleate treated groups. After acute treatment, mice were sacrificed at specific time points. Liver nuclear extracts were prepared and Nrf2 nuclear translocation was detected through Western blotting. To determine the effect of increasing doses of TRF on the extent of liver nuclear Nrf2 translocation and its implication on the expression levels of several Nrf2-regulated genes, mice were divided into 5 groups (control, 200, 500 and 1000 mg/kg TRF, and butylated hydroxyanisole-treated groups). After 14 days, mice were sacrificed and liver RNA was extracted for qPCR assay.

RESULTS

2000 mg/kg TRF administration initiated Nrf2 nuclear translocation within 30 min, reached a maximum level of around 1 h and dropped to half-maximal levels by 24 h. Incremental doses of TRF resulted in dose-dependent increases in liver Nrf2 nuclear levels, along with concomitant dosedependent increases in the expressions of Nrf2-regulated genes.

CONCLUSION

TRF activated the liver Nrf2 pathway resulting in increased expression of Nrf2-regulated cytoprotective genes.

The Association between Vigorous Physical Activity and Stress in Adolescents with Asthma

Asthma is a very common condition that affects 5-10% of the global population, and its prevalence is increasing. Vigorous physical activity (PA) is effective in improving cardiorespiratory fitness and managing stress. This study aimed to investigate the association between vigorous PA and stress among Korean adolescents with asthma using large-scale survey data. The questionnaire data of 57,303 adolescents were analyzed using raw data from the 2019 Korea Youth Risk Behavior Web-Based Survey. We performed logistic regression analysis to calculate the stress odds ratios (ORs) and 95% confidence intervals (CIs) for asthma and non-asthma groups using models 1 and 2. We also performed logistic regression analysis to calculate the stress OR for the asthma group with vigorous PA and non-vigorous PA using models 1, 2, and 3. Model 1 was adjusted for age, sex, obesity, smoking, and alcohol status; model 2 was further adjusted for household income, academic achievement, and comorbidities. Model 3 was further adjusted for moderate activity and resistance exercise. The OR of stress was 20% higher in the asthma group than in the non-asthma group (p < 0.05). In the fully adjusted models, the OR for the non-asthma group with vigorous PA versus non-vigorous PA was 0.89 (95% CI: 0.84-0.94). However, the OR for the asthma group with vigorous PA versus non-vigorous PA was 0.70 (95% CI: 0.57-0.86), indicating that adolescents who engage in vigorous PA had lower stress in the asthma group (p < 0.05). This study demonstrated that adolescents with asthma had higher stress levels than those without asthma; however, vigorous PA was associated with lower stress. These effects were more pronounced in adolescents with asthma.

Uncovering the Role of Oxidative Imbalance in the Development and Progression of Bronchial Asthma

Asthma is a chronic inflammatory disease of the airways related to epithelial damage, bronchial hyperresponsiveness to contractile agents, tissue remodeling, and luminal narrowing. Currently, there are many data about the pathophysiology of asthma; however, a new aspect has emerged related to the influence of reactive oxygen and nitrogen species (ROS and RNS) on the origin of this disease. Several studies have shown that an imbalance between the production of ROS and RNS and the antioxidant enzymatic and nonenzymatic systems plays an important role in the pathogenesis of this disease. Considering this aspect, this study is aimed at gathering data from the scientific literature on the role of oxidative distress in the development of inflammatory airway and lung diseases, especially bronchial asthma. For that, articles related to these themes were selected from scientific databases, including human and animal studies. The main findings of this work showed that the respiratory system works as a highly propitious place for the formation of ROS and RNS, especially superoxide anion, hydrogen peroxide, and peroxynitrite, and the epithelial damage is reflected in an important loss of antioxidant defenses that, in turn, culminates in an imbalance and formation of inflammatory and contractile mediators, such as isoprostanes, changes in the activity of protein kinases, and activation of cell proliferation signalling pathways, such as the MAP kinase pathway. Thus, the oxidative imbalance appears as a promising path for future investigations as a therapeutic target for the treatment of asthmatic patients, especially those resistant to currently available therapies.

PGC-1α regulates airway epithelial barrier dysfunction induced by house dust mite

Background

The airway epithelial barrier function is disrupted in the airways of asthmatic patients. Abnormal mitochondrial biogenesis is reportedly involved in the pathogenesis of asthma. However, the role of mitochondrial biogenesis in the airway barrier dysfunction has not been elucidated yet. This study aimed to clarify whether the peroxisome proliferator-activated receptor γ coactivator-1alpha (PGC-1α), a central regulator of mitochondrial biogenesis, is involved in the disruption of the airway barrier function induced by aeroallergens.

Methods

BEAS-2B cells were exposed to house dust mite (HDM) and the expressions of PGC-1α and E-cadherin, a junctional protein, were examined by immunoblotting. The effect of SRT1720, a PGC-1α activator, was investigated by immunoblotting, immunocytochemistry, and measuring the transepithelial electrical resistance (TEER) on the HDM-induced reduction in mitochondrial biogenesis markers and junctional proteins in airway bronchial epithelial cells. Furthermore,the effects of protease activated receptor 2 (PAR2) inhibitor, GB83, Toll-like receptor 4 (TLR4) inhibitor, lipopolysaccharide from Rhodobacter sphaeroides (LPS-RS), protease inhibitors including E64 and 4-(2-Aminoethyl) benzenesulfonyl fluoride hydrochloride (AEBSF) on the HDM-induced barrier dysfunction were investigated.

Results

The amounts of PGC-1α and E-cadherin in the HDM-treated cells were significantly decreased compared to the vehicle-treated cells. SRT1720 restored the expressions of PGC-1α and E-cadherin reduced by HDM in BEAS-2B cells. Treatment with SRT1720 also significantly ameliorated the HDM-induced reduction in TEER. In addition, GB83, LPS-RS, E64 and AEBSF prevented the HDM-induced reduction in the expression of PGC1α and E-cadherin.

Conclusions

The current study demonstrated that HDM disrupted the airway barrier function through the PAR2/TLR4/PGC-1α-dependent pathway. The modulation of this pathway could be a new approach for the treatment of asthma.

Abscisic acid suppresses the activation of NLRP3 inflammasome and oxidative stress in murine allergic airway inflammation

Abscisic acid (ABA), a well-known natural phytohormone reportedly exerts anti-inflammatory and anti-oxidative properties in diabetes and colitis. However, the efficacy of ABA against allergic airway inflammation and the underlying mechanism remain unknown. Herein, an OVA-induced murine allergic airway inflammation model was established and treated with ABA in the presence or absence of PPAR-γ antagonist GW9662. The results showed that ABA effectively stunted the development of airway inflammation, and concordantly downregulated OVA-induced activation of NLRP3 inflammasome, suppressed oxidative stress and decreased the expression of mitochondrial fusion/fission markers including Optic Atrophy 1 (OPA1), Mitofusion 2 (Mfn2), dynamin-related protein 1 (DRP1) and Fission 1 (Fis1). Moreover, ABA treatment further increased OVA-induced expression of PPAR-γ, while GW9662 abrogated the inhibitory effect of ABA on allergic airway inflammation as well as on the activation of NLRP3 inflammasome and oxidative stress. Consistently, ABA inhibited the activation of NLRP3 inflammasome, suppressed oxidative stress and mitochondrial fusion/fission in LPS-stimulated Raw264.7 cells via PPAR-γ. Collectively, ABA ameliorates OVA-induced allergic airway inflammation in a PPAR-γ dependent manner, and such effect of ABA may be associated with its inhibitory effect on NLRP3 inflammasome and oxidative stress. Our results suggest the potential of ABA or ABA-rich food in protecting against asthma.

Mini review: immunologic functions of dual oxidases in mucosal systems of vertebrates

Abstract Mucosal epithelial cells act as the first immunologic barrier of organisms, and contact directly with pathogens. Therefore, hosts must have differential strategies to combat pathogens efficiently. Reactive oxygen species (ROS), as a kind of oxidizing agents, participates in the early stage of killing pathogens quickly. Recent reports have revealed that dual oxidase (DUOX) plays a key role in mucosal immunity. And the DUOX is a transmembrane protein which produces ROS as their primary enzymatic products. This process is an important pattern for eliminating pathogens. In this review, we highlight the DUOX immunologic functions in the respiratory and digestive tract of vertebrates.

The Antioxidant Rosmarinic Acid Ameliorates Oxidative Lung Damage in Experimental Allergic Asthma via Modulation of NADPH Oxidases and Antioxidant Enzymes

Oxidative stress can induce lung damage and aggravate airway inflammation in asthma. Previously, we reported that rosmarinic acid (RA) exerted strong anti-inflammatory effects in a mouse allergic asthma model. Therefore, we hypothesized that RA might also have antioxidative effects in a superimposed asthma mouse model with oxidative lung damage challenged with ovalbumin (Ova) and hydrogen peroxide (H2O2). We evaluated the antioxidative and anti-asthmatic activity of RA and explored its possible mechanisms of action. Mice sensitized to Ova and challenged with Ova and H2O2 were treated with RA 1 h after challenge. RA treatment greatly diminished the number of inflammatory cells; decreased IL-4, IL-5, and IL-13 production; increased IFN-γ secretion; significantly downregulated ROS production; and markedly upregulated the activities of SOD, GPx, and CAT. Furthermore, RA treatment resulted in a significant increase in the expression of Cu/Zn SOD and a notable reduction in NOX-2 and NOX-4 expression in lung tissues. These findings suggest that RA may effectively alleviate oxidative lung damage and airway inflammation in asthma.

Lindera obtusiloba Attenuates Oxidative Stress and Airway Inflammation in a Murine Model of Ovalbumin-Challenged Asthma

Lindera obtusiloba is widespread in northeast Asia and used for treatment of improvement of blood circulation and anti-inflammation. In this study, we investigated anti-inflammatory and anti-oxidant effects of the methanolic extract of L. obtusiloba leaves (LOL) in an ovalbumin (OVA)-challenged allergic asthma model and tumor necrosis factor (TNF)-α-stimulated NCI-H292 cell. Female BALB/c mice were sensitized with OVA by intraperitoneal injection on days 0 and 14, and airway-challenged with OVA from days 21 to 23. Mice were administered 50 and 100 mg/kg of LOL by oral gavage 1 h before the challenge. LOL treatment effectively decreased airway hyper-responsiveness and inhibited inflammatory cell recruitment, Th2 cytokines, mucin 5AC (MUC5AC) in bronchoalveolar lavage fluid in OVA-challenged mice, which were accompanied by marked suppression of airway inflammation and mucus production in the lung tissue. LOL pretreatment inhibited the phosphorylation of mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) with suppression of activator protein (AP)-1 and MUC5AC in the lung tissue. LOL also down-regulated expression of inflammatory cytokines, and inhibited the activation of NF-κB in TNF-α-stimulated NCI-H292 cells. LOL elevated the translocation of nuclear factor-erythroid 2-related factor (Nrf-2) into nucleus concurrent with increase of heme oxyngenase-1 (HO-1) and NAD(P)H quinine oxidoreductase 1 (NQO1). Moreover, LOL treatment exhibited a marked increase in the anti-oxidant enzymes activities, whereas effectively suppressed the production of reactive oxygen species and nitric oxide, as well as lipid peroxidation in lung tissue of OVA-challenged mice and TNF-α-stimulated NCI-H292 cells. These findings suggest that LOL might serve as a therapeutic agent for the treatment of allergic asthma.

Apolipoprotein E negatively regulates murine allergic airway inflammation via suppressing the activation of NLRP3 inflammasome and oxidative stress

Apolipoprotein E (ApoE) has been reported as a steroid unresponsive gene and functions as a negative regulator of airway hyperreactivity (AHR) and goblet cell hyperplasia in house dust mite (HDM)-challenged mice. However, the role of ApoE in Ovalbumin (OVA)-induced allergic airway inflammation disease and the underlying mechanism are still unknown. In the present study, murine allergic airway inflammation was induced by inhaled OVA for consecutive 7 days in wild type (WT) and ApoE^-/- mice. In the OVA-induced model, the ApoE level in the bronchoalveolar lavage fluid (BALF) and lung tissues was significantly higher than that of control mice. And ApoE deficiency aggravated airway inflammation including leukocytes infiltration, goblet cell hyperplasia and IgE production as compared to those of WT mice after OVA- challenged, suggesting ApoE servers as an endogenous negative regulator of airway inflammation. Furthermore, OVA challenge elevated the activation of NLRP3 inflammasome with higher protein expression of NLRP3, caspase1 and IL-1β, enhanced oxidative stress with higher expression of 8-OHdG, nitrotyrosine and SOD2, increased the expression of mitochondrial fusion/fission markers including Optic Atrophy 1 (OPA1), Mitofusion 2 (Mfn2), dynamin-related protein 1 (DRP1) and Fission 1 (Fis1). However, these OVA-induced changes were augmented in ApoE^-/- mice. Collectively, our results demonstrated that the OVA-induced airway inflammation was aggravated in ApoE^-/- mice, and suggested that the underlying mechanism may be associated with the augmented activation of NLRP3 inflammasome and oxidative stress in ApoE^-/- mice, therefore targeting ApoE pathway might be a novel therapy approach for allergic airway diseases such as asthma.

Edaravone attenuates experimental asthma in mice through induction of HO-1 and the Keap1/Nrf2 pathway

Asthma is a chronic disease that threatens public health worldwide. Multiple studies have shown that oxidative stress plays an important role in the pathogenesis of asthma. Edaravone (Eda), a free radical scavenger, has been found to have a protective effect against lung injury due to its ability to eliminate reactive oxygen species. The present study aimed to investigate the effect of Eda on asthma and the mechanism underlying its actions. An experimental asthma model was induced in mice, before they were treated with different doses of Eda. Measurements of airway responsiveness to methacholine (Mch), cell counts and cytokine levels in bronchoalveolar lavage fluid (BALF) and of the oxidative products and antioxidant enzymes in lung tissue were taken in these asthma model mice and compared with control mice. Protein levels of kelch-like ECH-associated protein-1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2) and hemeoxygenase-1 (HO-1) were determined in the lung tissue of normal mice and Nrf2 and HO-1-deficient mice subject to the asthma model to investigate the mechanisms underlying Eda action. The results indicated that Eda effectively reduced airway responsiveness to Mch. The total number of cells and the numbers of eosinophils, lymphocytes and neutrophils in BALF of asthma model mice were also significantly reduced by Eda treatment when compared with normal saline treatment. Eda treatment significantly alleviated perivascular edema, peribronchial inflammation and macrophage infiltration in the alveolar space and decreased the levels of inflammatory cytokines released in BALF compared with control. Eda also significantly reduced the levels of oxidative stress markers in BALF and restored the levels of antioxidative enzyme, superoxide dismutase, when compared with control. The Keap1/Nrf2 ratio was significantly decreased with Eda compared with control due to an increase in Nrf2 and a decrease in Keap1 expression. HO-1 expression was increased by Eda. The airway responsiveness of Nrf2^-/- mice or HO-1^-/- mice to Mch was significantly higher compared with normal mice treated with Eda. Taken together, the results of the present study show that Eda exerts anti-inflammatory and antioxidative effects, which suggests a potential use for Eda in reduction of asthma severity. The activated Keap1/Nrf2 pathway and HO-1 may be involved in the anti-asthmatic effect of Eda.

Multiple exposures to organophosphate flame retardants alter urinary oxidative stress biomarkers among children: The Hokkaido Study

Organophosphate flame retardants (PFRs) are used as additives in plastics and other applications such as curtains and carpets as a replacement for brominated flame retardants. As such, exposure to PFR mixtures is widespread, with children being more vulnerable than adults to associated health risks such as allergies and inflammation. Oxidative stress is thought to be able to modulate the development of childhood airway inflammation and atopic dermatitis. To evaluate these associations, the present study investigated the relationship between urinary PFR metabolites, their mixtures and urinary oxidative stress biomarkers in children as part of the Hokkaido Study on Environment and Children's Health. The levels of the oxidative stress biomarkers, such as 8-hydroxy-2'-deoxyguanosine (8-OHdG), hexanoyl-lysine (HEL), and 4-hydroxynonenal (HNE), and of 14 PFR metabolites were measured in morning spot urine samples of 7-year-old children (n = 400). Associations between PFR metabolites or PFR metabolite mixtures and oxidative stress biomarkers were examined by multiple regression analysis and weighted quantile sum regression analysis, respectively. We found that the non-chlorinated PFR metabolites, 2-ethylhexyl phenyl phosphate (EHPHP), bis(2-butoxyethyl) phosphate (BBOEP), and diphenyl phosphate (DPHP) were associated with increased levels of oxidative stress biomarkers. Furthermore, the PFR metabolite mixture was associated with increased levels of HEL and HNE, but not 8-OHdG. The combination of elevated top 2 PFR metabolites was not associated with higher urinary oxidative stress marker levels. This is the first study to report associations between urinary PFR metabolites and oxidative stress biomarkers among children.

Upregulated thioredoxin and its reductase prevent H2O2-induced growth inhibition and death in human pulmonary artery smooth muscle cells

The thioredoxin (Trx) system controls cellular redox in vascular smooth muscle cells. The present study investigated the roles of Trx1 and Trx reductase1 (TrxR1) proteins in regulation of cell growth, death, reactive oxygen species (ROS) and glutathione (GSH) levels in hydrogen peroxide (H₂O₂)-treated human pulmonary artery smooth muscle (HPASM) cells. H₂O₂ induced growth inhibition and cell death in HPASM cells over 24 h. Overexpression of Trx1 and TrxR1 using adenoviruses significantly weakened cell growth inhibition and cell death caused by H₂O₂. Increases in ROS levels including mitochondrial superoxide anion (O₂^•-) were observed as early as 5-30 min after H₂O₂ addition. Administration of adTrxR1 attenuated H₂O₂-induced increases in ROS levels at 30-180 min. adTrx1 and adTrxR1 significantly reduced the increases in O₂^•- level in H₂O₂-treated HPASM cells at 24 h. Furthermore, HPASM cells transfected with Trx1 or TrxR1 siRNA showed increases in ROS levels with or without H₂O₂ at 5 min. While H₂O₂ transiently decreased GSH level at 5 min, Trx1 and TrxR1 siRNA intensified the decrease in GSH level. In conclusion, upregulation of Trx1 and TrxR1 significantly attenuated cell growth inhibition and death in H₂O₂-treated HPASM cells. As a whole, Trx-related adenoviruses diminished H₂O₂-induced ROS level in HPASM cells whereas Trx-related siRNAs increased ROS levels and decreased GSH level in these cells.

Nitrosative stress in patients with asthma-chronic obstructive pulmonary disease overlap

BACKGROUND

Asthma-chronic obstructive pulmonary disease overlap (ACO) has frequent exacerbations and a poor quality of life and prognosis compared with those of chronic obstructive pulmonary disease alone. However, the pathogenesis of ACO has not been fully elucidated yet.

OBJECTIVES

The aim of this study was to investigate nitrosative stress, which causes a redox imbalance and tissue inflammation in the airways of patients with ACO, and to evaluate the relationship between nitrosative stress and the clinical course in study subjects.

METHODS

Thirty healthy subjects and 56 asthmatic patients participated in this study. The asthmatic patients were divided into 33 asthmatic patients and 23 patients with ACO. The study subjects had been followed prospectively for 2 years to evaluate the clinical course. Nitrosative stress was evaluated based on the production of 3-nitrotyrosine (3-NT) in sputum cells.

RESULTS

Production of 3-NT was significantly enhanced in patients with ACO compared with that in asthmatic patients. Amounts of reactive persulfides and polysulfides, newly identified powerful antioxidants, were significantly decreased in the ACO group. Baseline levels of 3-NT were significantly correlated with the frequency of exacerbations and decrease in FEV₁ adjusted by age, smoking history, and blood eosinophil count. The 3-NT-positive cells were also significantly correlated with amounts of proinflammatory chemokines and cytokines.

CONCLUSIONS

These findings suggested that greater nitrosative stress occurred in the airways of patients with ACO, and the degree of nitrosative stress was correlated with an impairment in the clinical course. Nitrosative stress might be related to the pathogenesis of ACO.

Vitamin D alleviates airway remodeling in asthma by down-regulating the activity of Wnt/β-catenin signaling pathway

Vitamin D exerts a protective role in asthma; however, the molecular mechanisms underlying the vitamin D-attenuated asthma airway remodeling are yet to be elucidated. In this study, Sprague-Dawley (SD) rats were randomly divided into four groups: control, asthma, vitamin D 50 ng/mL, and vitamin D 100 ng/mL. The treatment with 100 ng/mL vitamin D remarkably reduced the thickness of the airway smooth muscle, collagen deposition, and the alpha-smooth muscle actin (α-SMA) mass and airway inflammation. Conversely, the treatment by vitamin D significantly up-regulated the serum levels of 25(OH)₂D₃ that were decreased in asthma. The putative signaling pathway of vitamin D was based on Wnt5a and β-catenin expression assessed by quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR) and Western blot, which revealed that the administration of vitamin D significantly decreased the activity of Wnt/β-catenin signaling pathway. These results suggested that administration of vitamin D alleviated the airway remodeling in asthma by down-regulating the activity of Wnt/β-catenin signaling pathway.

Hyperbilirubinemia, Phototherapy, and Childhood Asthma

OBJECTIVES

Our aim was to quantify the associations of both hyperbilirubinemia and phototherapy with childhood asthma using a population-based cohort with total serum bilirubin (TSB) levels.

METHODS

Retrospective cohort study of infants born at ≥35 weeks' gestation in the Kaiser Permanente Northern California health system (n = 109 212) from 2010 to 2014. Cox models were used to estimate hazard ratios (HRs) for a diagnosis of asthma.

RESULTS

In the study, 16.7% of infants had a maximum TSB level of ≥15 mg/dL, 4.5% of infants had a maximum TSB level of ≥18 mg/dL, and 11.5% of infants received phototherapy. Compared with children with a maximum TSB level of 3 to 5.9 mg/L, children with a TSB level of 9 to 11.9 mg/dL, 12 to 14.9 mg/dL, and 15 to 17.9 mg/dL were at an increased risk for asthma (HR: 1.22 [95% confidence interval (CI): 1.11-1.3], HR: 1.18 [95% CI: 1.08-1.29], and HR: 1.30 [95% CI: 1.18-1.43], respectively). Children with a TSB level of ≥18 mg/dL were not at an increased risk for asthma (HR: 1.04; 95% CI: 0.90-1.20). In propensity-adjusted analyses, phototherapy was not associated with asthma (HR: 1.07; 95% CI: 0.96-1.20).

CONCLUSIONS

Modest levels of hyperbilirubinemia were associated with an increased risk of asthma, but an association was not seen at higher levels. No dose-response relationship was seen. Using phototherapy to prevent infants from reaching these modest TSB levels is unlikely to be protective against asthma.

Hydrogen Sulfide Protects against Chemical Hypoxia-Induced Injury via Attenuation of ROS-Mediated Ca2+ Overload and Mitochondrial Dysfunction in Human Bronchial Epithelial Cells

Oxidative stress induced by hypoxia/ischemia resulted in the excessive reactive oxygen species (ROS) and the relative inadequate antioxidants. As the initial barrier to environmental pollutants and allergic stimuli, airway epithelial cell is vulnerable to oxidative stress. In recent years, the antioxidant effect of hydrogen sulfide (H₂S) has attracted much attention. Therefore, in this study, we explored the impact of H₂S on CoCl₂-induced cell injury in 16HBE14o- cells. The effect of CoCl₂ on the cell viability was detected by Cell Counting Kit (CCK-8) and the level of ROS in 16HBE14o- cells in response to varying doses (100–1000 μmol/L) of CoCl₂ (a common chemical mimic of hypoxia) was measured by using fluorescent probe DCFH-DA. It was shown that, in 16HBE14o- cells, CoCl₂ acutely increased the ROS content in a dose-dependent manner, and the increased ROS was inhibited by the NaHS (as a donor of H₂S). Moreover, the calcium ion fluorescence probe Fura-2/AM and fluorescence dye Rh123 were used to investigate the intracellular calcium concentration ([Ca²⁺]_i) and mitochondria membrane potential (MMP) in 16HBE14o- cells, respectively. In addition, we examined apoptosis of 16HBE14o- cells with Hoechst 33342. The results showed that the CoCl₂ effectively elevated the Ca²⁺ influx, declined the MMP, and aggravated apoptosis, which were abrogated by NaHS. These results demonstrate that H₂S could attenuate CoCl₂-induced hypoxia injury via reducing ROS to perform an agonistic role for the Ca²⁺ influx and MMP dissipation.

Estrogen Modulates the Sensitivity of Lung Vagal C Fibers in Female Rats Exposed to Intermittent Hypoxia

Obstructive sleep apnea is mainly characterized by intermittent hypoxia (IH), which is associated with hyperreactive airway diseases and lung inflammation. Sensitization of lung vagal C fibers (LVCFs) induced by inflammatory mediators may play a central role in the pathogenesis of airway hypersensitivity. In females, estrogen interferes with inflammatory signaling pathways that may modulate airway hyperreactivity. In this study, we investigated the effects of IH on the reflex and afferent responses of LVCFs to chemical stimulants and lung inflammation in adult female rats, as well as the role of estrogen in these responses. Intact and ovariectomized (OVX) female rats were exposed to room air (RA) or IH for 14 consecutive days. On day 15, IH enhanced apneic responses to right atrial injection of chemical stimulants of LVCFs (e.g., capsaicin, phenylbiguanide, and α,β-methylene-ATP) in intact anesthetized females. Rats subjected to OVX prior to IH exposure exhibited an augmented apneic response to the same dose of stimulants compared with rats subjected to other treatments. Apneic responses to the stimulants were completely abrogated by bilateral vagotomy or perivagal capsaicin treatment, which blocked the neural conduction of LVCFs. Electrophysiological experiments revealed that in IH-exposed rats, OVX potentiated the excitability of LVCFs to stimulants. Moreover, LVCF hypersensitivity in rats subjected to OVX prior to IH exposure was accompanied by enhanced lung inflammation, which was reflected by elevated inflammatory cell infiltration in bronchoalveolar lavage fluid, lung lipid peroxidation, and protein expression of inflammatory cytokines. Supplementation with 17β-estradiol (E2) at a low concentration (30 μg/ml) but not at high concentrations (50 and 150 μg/ml) prevented the augmenting effects of OVX on LVCF sensitivity and lung inflammation caused by IH. These results suggest that ovarian hormones prevent the enhancement of LVCF sensitivity and lung inflammation by IH in female rats, which are related to the effect of low-dose estrogen.

TGF-β/SMAD4 mediated UCP2 downregulation contributes to Aspergillus protease-induced inflammation in primary bronchial epithelial cells

Elevated levels of mitochondrial reactive oxygen species (ROS) can lead to the development of airway inflammation. In this study, we investigated the role of Aspergillus proteases—which contribute to the pathogenesis of Aspergillus-induced diseases such as allergic bronchopulmonary aspergillosis, hypersensitivity pneumonitis, and atopic asthma—and their mechanisms of action in airway inflammation using primary human bronchial epithelial cells, and evaluated the inflammatory responses mediated by mitochondrial ROS. We found that Aspergillus proteases regulated the expression of multifunctional inflammatory cytokines such as interleukin (IL)− 1β, − 6, and − 8, and transforming growth factor (TGF)-β, which stimulated cytokine production and chemokines involved in leukocyte migration and activated an inflammatory cascade. Expression of these factors and activator protein (AP)− 1 were decreased by treatment with the mitochondrial ROS scavenger Mito-TEMPO, suggesting that mitochondria are important sources of ROS in the context of inflammatory response by Aspergillus protease. The regulation of mitochondrial ROS influenced the production of proinflammatory mediators by preventing mitochondrial ROS-induced AP-1 activation in airway epithelial cells. In addition, Aspergillus protease-mediated mitochondrial ROS production was associated with downregulation of uncoupling protein (UCP)− 2 expression by TGF-β-SMAD4 signaling, which may play a regulatory role in mitochondrial ROS formation during fungal protease-mediated epithelial inflammation. This improved understanding of the allergenic fungal protease-induced inflammatory mechanism in the bronchial epithelium will help in developing intervention strategies for the regulation of inflammatory response in allergic airway diseases.

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Fungal protease induce inflammatory cytokines, ROS, and mitochondrial ROS production.

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Fungal protease-induced mitochondrial ROS regulate AP-1 activation and neutrophil migration.

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Fungal protease-induced mitochondrial ROS modulate airway epithelial inflammation.

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Downregulation of UCP-2 expression by TGF-β-SMAD4 signaling induce mitochondrial ROS production.

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TGF-β/SMAD4 mediated UCP2 downregulation contributes to fungal protease-induced inflammation.

Inhalation of hydrogen gas attenuates airway inflammation and oxidative stress in allergic asthmatic mice

Background

Asthma is a worldwide common chronic airway disease that cannot be cured and results in the huge burden in public health. Oxidative stress was considered an important mechanism in the pathogenesis of asthma. Hydrogen gas been demonstrated to function as a novel antioxidant and exert therapeutic antioxidant activity in a number of diseases and the function of this nontoxic gas in asthma was unclear. The purpose of the study aims to examine the effect of inhalation hydrogen gas on the pathophysiology of a mouse model of asthma.

Methods

A murine model of ovalbumin (OVA)-induced allergic airway inflammation was used in this study. Briefly, Mice were sensitized to ovalbumin and received inhalation of 67% high concentration of hydrogen gas for 60 min once a day for 7 consecutive days after OVA or PBS challenge respectively. Lung function was assessed in the apparatus with 4 channels of biological signal system. Morphology and goblet cell hyperplasia were stained by H/E and Periodic acid-Schiff staining. Cytologic classification in the bronchial alveolar lavage fluid (BALF) was analyzed by Wright Giemsa staining. Serum, BALF and lung tissue were collected for biochemical assay. One-way analysis of variance (ANOVA) was used to determine statistical significance between groups. Multiple comparisons were made by Bonferroni’s Multiple Comparison Test by using GraphPad Prism 5 software.

Results

Inhalation of hydrogen gas abrogated ovalbumin-induced the increase in lung resistance. Concomitantly, the asthmatic mice showed severe inflammatory infiltration and goblet cell hyperplasia which were reversed by hydrogen gas inhalation. Hydrogen gas inhalation reduced significantly the number of total cells, eosinophils and lymphocytes in BALF. Increased level of IL-4, IL-13, TNF-α and CXCL15 in the BALF and IL-4 in the serum were decreased significantly after inhalation. Hydrogen gas inhalation markedly upregulated the activity of decreased superoxide dismutase and significantly attenuated the increased level of malondialdehyde and myeloperoxidase.

Conclusions

Hydrogen gas inhalation improves lung function and protects established airway inflammation in the allergic asthmatic mice model which may be associated with the inhibition of oxidative stress process. This study provides a potential alternative therapeutic opportunity for the clinical management of asthma.

Using the Inflammacheck Device to Measure the Level of Exhaled Breath Condensate Hydrogen Peroxide in Patients With Asthma and Chronic Obstructive Pulmonary Disease (The EXHALE Pilot Study): Protocol for a Cross-Sectional Feasibility Study

BACKGROUND

Asthma and Chronic Obstructive Pulmonary Disease (COPD) are common conditions that affect over 5 million people in the United Kingdom. These groups of patients suffer significantly from breathlessness and recurrent exacerbations that can be difficult to diagnose and go untreated. A common feature of COPD and asthma is airway inflammation that increases before and during exacerbations. Current methods of assessing airway inflammation can be invasive, difficult to perform, and are often inaccurate. In contrast, measurement of exhaled breath condensate (EBC) hydrogen peroxide (H₂O₂) is performed during normal tidal breathing and is known to reflect the level of global inflammation in the airways. There is a need for novel tools to diagnose asthma and COPD earlier and to detect increased airway inflammation that precedes an exacerbation.

OBJECTIVE

The aim of this study was to explore the use of a new handheld device (called Inflammacheck) in measuring H₂O₂ levels in EBC. We will study whether it can measure EBC H₂O₂ levels consistently and whether it can be used to differentiate asthma and COPD from healthy controls.

METHODS

We will perform a cross-sectional, feasibility, pilot study of EBC H₂O₂ levels, as measured by Inflammacheck, and other markers of disease severity and symptom control in patients with asthma and COPD and volunteers with no history of lung disease. Participants will be asked to provide an exhaled breath sample for measurement of their EBC H₂O₂ using Inflammacheck. The result will be correlated with disease stage, spirometry, fractional exhaled nitric oxide (FeNO), and symptom control scores.

RESULTS

This study's recruitment is ongoing; it is anticipated that the results will be available in 2018.

CONCLUSIONS

The EXhaled Hydrogen peroxide As a marker of Lung diseasE (EXHALE) pilot study will provide an evaluation of a new method of measuring EBC H₂O₂. It will assess the device's consistency and ability to distinguish airway inflammation in asthma and COPD compared with healthy controls.

Oxidative stress and cellular pathways of asthma and inflammation: Therapeutic strategies and pharmacological targets

Asthma is a complex inflammatory disease characterized by airway inflammation and hyperresponsiveness. The mechanisms associated with the development and progression of asthma have been widely studied in multiple populations and animal models, and these have revealed involvement of various cell types and activation of intracellular signaling pathways that result in activation of inflammatory genes. Significant contributions of Toll-like-receptors (TLRs) and transcription factors such as NF-кB, have been reported as major contributors to inflammatory pathways. These have also recently been associated with mechanisms of oxidative biology. This is of important clinical significance as the observed inefficacy of current available treatments for severe asthma is widely attributed to oxidative stress. Therefore, targeting oxidizing molecules in conjunction with inflammatory mediators and transcription factors may present a novel therapeutic strategy for asthma. In this review, we summarize TLRs and NF-кB pathways in the context of exacerbation of asthma pathogenesis and oxidative biology, and we discuss the potential use of polyphenolic flavonoid compounds, known to target these pathways and possess antioxidant activity, as potential therapeutic agents for asthma.

Role of oxidative stress in liver toxicity induced by nickel oxide nanoparticles in rats

The aim of the present study was to explore the role of oxidative stress in liver toxicity induced by nickel oxide nanoparticles (nano‑NiO) in rats. Male Wistar rats received saline (control), nano‑NiO [0.015, 0.06 or 0.24 mg/kg body weight (b.w.)] or micro‑NiO (0.24 mg/kg b.w.) by intratracheal instilling twice a week for 6 weeks. Liver tissues were then collected and examined for biomarkers of nitrative and oxidative stress, as well as mRNA expression of heme oxygenase (HO)‑1 and metallothionein (MT)‑1. The results demonstrated that the NiO exposure groups had increased liver wet weight and coefficient to body weight, as well as liver pathological changes, evidenced as cellular edema, hepatic sinus disappeara-nce and binucleated hepatocytes. The activities of total nitric oxide synthase and inducible nitric oxide synthase, and the nitric oxide content, were increased in the 0.24 mg/kg nano‑NiO group compared with the control group. The MT‑1 mRNA expression levels were downregulated, while HO‑1 mRNA was upregulated in the 0.24 mg/kg nano‑NiO exposure group compared with the control group. In addition, abnormal changes of hydroxyl radical, lipid peroxidation, catalase, glutathione peroxidase, total superoxide dismutase and total antioxidative capacity were observed in the liver tissues of the 0.24 mg/kg nano‑NiO exposure group, compared with the control group. The present results therefore indicated that nano‑NiO‑induced liver toxicity may be associated with nitrative and oxidative stress in rats.

The Contribution of Oxidative Stress and Inflamm-Aging in Human and Equine Asthma

Aging is associated with a dysregulation of the immune system, leading to a general pro-inflammatory state of the organism, a process that has been named inflamm-aging. Oxidative stress has an important role in aging and in the regulation of immune responses, probably playing a role in the development of age-related diseases. The respiratory system function physiologically declines with the advancement of age. In elderly asthmatic patients, this may contribute to disease expression. In this review, we will focus on age-related changes affecting the immune system and in respiratory structure and function that could contribute to asthma occurrence, and/or clinical presentation in the elderly. Also, naturally occurring equine asthma will be discussed as a possible model for studying the importance of oxidative stress and immun-aging/inflamm-aging in humans.

Role of NF-κB activation and Th1/Th2 imbalance in pulmonary toxicity induced by nano NiO

With the progress of nanotechnology, nano nickel oxide (NiO) has been extensively used as sensors, battery electrodes, catalysts, and cosmetics. Previous researches verified that nano NiO could exert pulmonary toxicity, but its mechanism was unclear. To shed light upon this, the role of nuclear factor-κB (NF-κB) activation and Th1/Th2 imbalance were to explore in pulmonary damage induced by nano NiO. Male Wistar rats were randomized into control group, nano NiO groups (0.015, 0.06, and 0.24 mg kg^-1 ) and micro NiO group (0.024 mg kg^-1 ) and treated by intratracheal instillation twice a week for 6 weeks. The results showed that the abnormal changes induced by nano NiO were found on indicators of nitrative stress (NO, TNOS, and iNOS), inflammatory cytokines (TNF-α, IL-2, and IL-10) and cytokine-induced neutrophil chemoattractants (CINC-1, CINC-2αβ, and CINC-3) in lung tissue. In addition, nano NiO instillation induced the upregulated mRNA and protein expression of NF-κB, inhibitor of κB kinase-α (IKK-α) and nuclear factor-inducing kinase (NIK). The protein content of GATA-3 increased as well as T-bet decreased in nano NiO groups, and the ratio of T-bet/GATA-3, as a key evaluation indicator of Th1/Th2 balance, was lower than the control group. The findings indicated that nano NiO could enhance the nitrative stress and inflammatory response in lung tissue, and its mechanism was related to the NF-κB activation and Th1/Th2 imbalance. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1354-1362, 2017.

Phthalate-induced oxidative stress and association with asthma-related airway inflammation in adolescents

BACKGROUND

In Belgium, around 8.5% of the children have asthmatic symptoms. Increased asthma risk in children has been reported in relation to exposure to phthalate plasticizers but the underlying mechanisms are largely unknown.

AIM

The aim of this study was to identify if oxidative stress, assessed by excision of 8-hydroxydeoxyguanosine (8-OHdG) from damaged DNA, is an intermediate marker for the association between phthalate exposure and doctor-diagnosed asthma.

MATERIAL AND METHODS

In 418 14-15-year-old youngsters, recruited as a representative sample of residents of Flanders (Belgium), personal exposure to phthalates was assessed by measuring phthalate metabolites in urine: mono(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), mono-n-butyl phthalate (MnBP), mono-benzyl phthalate (MBzP), mono-isobutyl phthalate (MiBP) and mono-ethyl phthalate (MEP). Analysis of 8-OHdG in urine was used as a sensitive biomarker of oxidative stress at the level of DNA. The presence of doctor-diagnosed asthma was elicited by a self-administered questionnaire. Associations were assessed using multiple linear and logistic regression models. Mediation was tested using Baron and Kenny's regression approach.

RESULTS

A significant increased risk of a youngster being diagnosed with asthma was found for both urinary MnBP (metabolite of dibutyl phthalate (DBP)) and the sum of the three di(2-ethylhexyl) phthalate metabolites (ΣDEHP=MEHP+MEHHP+MEOHP), with respective odds ratio of 1.84 [95% CI: 1.02, 3.32] for MnBP and 1.94 [95% CI: 1.07, 3.51] for ΣDEHP. In addition, we observed significant associations between all urinary phthalate metabolites and increased urinary levels of 8-OHdG. The associations were stronger in girls than in boys. We did not found evidence that 8-OHdG was associated with doctor-diagnosed asthma.

CONCLUSION

The results of our study are in line with other findings from epidemiological surveys and raise further concern about DEHP and DBP as risk factors for asthma, however, the underlying mechanisms are not yet well understood.

Chrysin inhibits human airway smooth muscle cells proliferation through the extracellular signal-regulated kinase 1/2 signaling pathway

Asthma is a chronic airway inflammatory disease characterized by an increased mass of airway smooth muscle (ASM). Chrysin (5,7-dihydroxyflavone), a natural flavonoid, has been shown to exert multiple biological activities, including anti-inflammatory, anti-proliferative and anti-oxidant effects, as well as the potency to ameliorate asthma in animal models. The objective of the present study was to identify the underlying mechanism of the therapeutic effects of chrysin. The impact of chrysin on basal and platelet-derived growth factor (PDGF)-induced proliferation and apoptosis of human airway smooth muscle cells (HASMCs) was investigated. Furthermore, the activation of the extracellular signal-regulated protein kinase (ERK) signaling pathway was evaluated in HASMCs. The results revealed that chrysin significantly inhibited basal as well as PDGF-induced HASMC proliferation, most likely through the suppression of ERK1/2 phosphorylation. However, chrysin did not significantly reduce PDGF-induced apoptosis of HASMCs. The present study indicated that chrysin may be a promising medication for controlling airway remodeling and clinical manifestations of asthma.