Airway Hyperresponsiveness Research Articles

Self-reported symptoms associated with the use of printer and photocopier machines: Results from the nano-Control, International Foundation survey.

To document adverse health effects among office, copy and print shop workers using the nano-Control International Organization Survey. Self-reported information on 16 health outcomes and three surrogate exposure variables were collected from 1998 individuals between 1999-2010. Logistic regression models, adjusted for age, gender, and smoking status, assessed the association between printer exposure and health symptoms. Among the participants, 61.9 % were office workers, 5.5% technicians and 23.3% held other professions. Technicians had a higher risk for cancer compared to office workers (OR = 2.5, p-value <0.01). Visible toner dust exposure was associated with chronic fatigue (OR = 9.6, <0.01), bronchial hyperresponsiveness (OR = 5.1, <0.01), cardiovascular diseases (OR = 3.6, <0.01), asthma, allergies, and other diseases (OR range 1.4 -3.2, <0.01). The increased chronic and acute health risks among these workers warrant further investigations of causal associations.

Inhibition of MARCKS phosphorylation attenuates of dendritic cell migration in a murine model of acute asthma

BackgroundMARCKS (myristoylated alanine-rich C kinase substrates) serves as a substrate for protein kinase C, residing in the plasma membrane while acts as an actin filament crosslinking protein. This investigation aims to elucidate phosphorylated MARCKS (p-MARCKS) levels and activity in allergic asthma patients and explore the therapeutic potential of peptide inhibitors targeting p-MARCKS in an acute mouse model of allergic asthma. MethodsImmunohistochemistry and histology staining were employed on lung tissue slides to evaluate p-MARCKS expression and allergic asthma symptoms. Airway resistance was measured using invasive whole-body plethysmography. Flow cytometry detected lung dendritic cell migration, and migration/maturation assays were conducted on isolated murine bone marrow-derived dendritic cells (BM-DCs). ResultsElevated p-MARCKS expression was observed in both human asthmatic tissues and animal models immunized with ovalbumin or Alternaria alternata. Remarkably, asthmatic individuals showed elevated high p-MARCKS expression in lung tissues. Intraperitoneal injection of the peptide MPS, targeting the MARCKS phosphorylation site domain, before allergen challenged, effectively suppressed MARCKS phosphorylation in murine lung tissues. MPS inhibited both in vivo and in vitro migration and maturation of dendritic cells (BM-DCs) and reduced Th2-related lymphocyte activation in bronchoalveolar lavage fluid (BALF). MPS pretreatment additionally suppressed all symptoms associated with allergic airway asthma, including a reduction in inflammatory cell influx, airway mucous cell metaplasia, and airway hyperreactivity. ConclusionThese findings suggest that phosphorylated MARCKS occurs in asthmatic lung tissue, and the inhibition of MARCKS phosphorylation by the MPS peptide reduces dendritic cell migration and Th2-related lymphocytes in the lungs in a murine model of acute asthma.

Itaconate suppresses house dust mite-induced allergic airways disease and Th2 cell differentiation

Itaconate was initially identified as an antimicrobial compound produced by myeloid cells. Beyond its antimicrobial role, itaconate may also serve as a crucial metabolic and immune modulator. We therefore examined the roles of aconitate decarboxylase 1 (Acod1) and itaconate in house dust mite (HDM)-sensitized and −challenged mice, a model of T helper 2 (Th2)-driven allergic airways disease. HDM treatment induced lung Acod1 mRNA expression and bronchoalveolar lavage (BAL) itaconate levels in wild-type C57BL/6 mice. Acod1 knockout mice (Acod1-KO) with negligible BAL itaconate showed heightened HDM-induced type 2 cytokine expression, increased serum IgE, and enhanced recruitment of Th2 cells in the lung, indicating a shift towards a more pronounced Th2 immune response. Acod1-KO mice also showed increased eosinophilic airway inflammation and hyperresponsiveness. Experiments in chimeric mice demonstrated that bone marrow from Acod1-KO mice is sufficient to increase type 2 cytokine expression in wild-type mice, and that restitution of bone marrow from wild type mice attenuates mRNA expression of Th2 cytokines in Acod1-KO mice. Specific deletion of Acod1 in lysozyme-secreting macrophages (LysM-cre+Acod1flox/flox) recapitulated the exaggerated phenotype observed in whole-body Acod1-KO mice. Adoptive transfer of Acod1-KO bone marrow-derived macrophages also increased lung mRNA expression of Th2 cytokines. In addition, treatment of Th2-polarized CD4 cells with itaconate impeded Th2 cell differentiation, as shown by reduced expression of Gata3 and decreased release of IL-5 and IL-13. Finally, public datasets of human samples show lower Acod1 expression in subjects with allergic asthma, consistent with a protective role of itaconate in asthma pathogenesis. Together, these data suggest that itaconate plays a protective, immunomodulatory role in limiting airway type 2 inflammation after allergen challenge by attenuating T cell responses.

Serum Vitamin D Status in Patients with Asthma-COPD Overlap

Introduction: Asthma-COPD overlap shared its risk factors with asthma and COPD, including development in the later decades of life, airway hyper-responsiveness, often tobacco smoke exposure, and progressive loss of lung function. It has been shown that this group of patients might possess vitamin D deficiency. By assessing the level of vitamin D we can identify the deficiency earlier and can give appropriate supplements. Objective: This study was done to assess the serum vitamin D status in patients with Asthma-COPD overlap. Materials and Methods: This cross-sectional study was carried out in the Department of Physiology of Bangabandhu Sheikh Mujib Medical University, Dhaka, from January 2018 to July 2018. Total 47 men subjects age ranged between 40-70 years were involved in this study. Among them 23 (twenty three) men (40-70 years) were involved as study group (Group II) and 24 (twenty four) men (40-70 years) were taken as control group (Group I). Results: The results were expressed as mean with standard error (mean±SEM). The data were statistically analyzed by Graphpad prism (Version 7) using independent sample ‘t’ test. The mean (±SEM) of serum vitamin D of Group I and Group II were 16.37±0.78 kg/m2 &amp; 18.47±1.01 ng/ml respectively. Conclusion: Vitamin D deficiency is present in both groups. By this study we recommended that routine estimation of this parameter is important for early detection and prevention of complication related to Asthma-COPD overlap for managing a healthy life. Medicine Today 2024, Vol.36 (2): 120-123

Clara cell 10 (CC10) protein attenuates allergic airway inflammation by modulating lung dendritic cell functions

Allergic asthma is a complex inflammatory disorder predominantly orchestrated by T helper 2 (Th2) lymphocytes. The anti-inflammatory protein Clara Cell 10-kDa (CC10), also known as secretoglobin family 1A member 1 (SCGB1A1), shows promise in modulating respiratory diseases. However, its precise role in asthma remains unclear. This study examines the potential of CC10 to suppress allergic asthma inflammation, specifically assessing its regulatory effects on Th2 cell responses and dendritic cells (DCs). Lower CC10 levels in asthma were observed and correlated with increased IgE and lymphocytes. Cc10−/− mice exhibited exacerbated allergic airway inflammation marked by increased inflammatory cell infiltration, Th2 cytokines, serum antigen-specific IgE levels, and airway hyperresponsiveness (AHR) in house dust mite (HDM)-induced models. Conversely, recombinant CC10 significantly attenuated these inflammatory responses. Intriguingly, CC10 did not directly inhibit Th cell activation but significantly downregulated the population of CD11b+CD103− DCs subsets in lungs of asthmatic mice and modulated the immune activation functions of DCs through NF-κB signaling pathway. The mixed lymphocyte response assay revealed that DCs mediated the suppressive effect of CC10 on Th2 cell responses. Collectively, CC10 profoundly mitigates Th2-type allergic inflammation in asthma by modulating lung DC phenotype and functions, highlighting its therapeutic potential for inflammatory airway conditions and other related immunological disorders.

The influence of air pollution on asthma in athletes – a brief review of the literature

Introduction and purpose Air pollution, stemming from natural occurrences and human activities, significantly threatens global health, particularly impacting respiratory conditions like asthma. Air pollution substantially influences asthma exacerbation in athletes, a group particularly vulnerable due to their high physical activity levels and increased respiratory demands. Key pollutants, including particulate matter (PM), ground-level ozone (O3), sulfur dioxide (SO2), and nitrogen dioxide (NO2), play critical roles in asthma development and exacerbation. The State of Knowledge Asthma, a chronic inflammatory disease influenced by genetic predisposition and environmental factors like air pollution, is characterized by airway hyperresponsiveness, obstruction, and chronic inflammation, leading to symptoms such as shortness of breath, coughing, wheezing, and chest tightness. Research highlights the link between air pollution exposure and asthma development, with PM2.5 exposure associated with increased asthma risk and pollutants exacerbating symptoms, especially in children. Athletes inhaling air pollutants during exercise face increased airway inflammation, mucus production, and bronchospasm, worsening asthma symptoms like wheezing and shortness of breath. Chronic exposure decreases lung function, increasing reliance on medication and limiting outdoor training on polluted days. Summary Effective asthma management amidst air pollution requires personal, community, and governmental measures. Patients should minimize exposure by wearing N95 masks and choosing low-traffic routes. Governments must monitor pollution, inform the public, and control emissions through alternative fuels and technologies. Adhering to WHO air quality guidelines could prevent many new asthma cases, emphasizing comprehensive air quality management's importance, especially among vulnerable populations like children.

Prior Bariatric Surgery Predicts Lower Life-Threatening Morbidity in Patients Admitted for Acute Allergic Reaction and Anaphylaxis: a Propensity Score-Matched Analysis of the U.S. Nationwide Inpatient Sample, 2005–2018

PurposeAcute allergic reactions may occur in susceptible individuals following exposure to various allergens. Obesity is linked to allergic reactions, and weight loss from bariatric surgery may attenuate the severity of certain conditions such as airway hyperresponsiveness in asthma. This retrospective observational study investigates associations between prior bariatric surgery and lower risk for life-threatening conditions in patients hospitalized with acute allergic reactions and anaphylaxis.Materials and MethodsAdults ≥ 18 years old diagnosed with morbid obesity and admitted to US hospitals with acute allergic reactions/anaphylaxis were included. All data were extracted from the US Nationwide Inpatient Sample (NIS) database 2005–2018. Patients without information on in-hospital mortality, discharge destination, hospital costs, and length of stay (LOS) were excluded. Patients were divided into two groups based on prior bariatric surgery or not. All diagnoses were verified through ICD-9 and ICD-10 codes. Between-group differences and associations between variables were evaluated using logistic regression analysis.ResultsAfter matching, patients with prior bariatric surgery had significantly lower proportions of any life-threatening morbidity (37.2% vs. 47.4%), respiratory distress or failure (11.2% vs. 17.0%), pneumonia or severe infection (7.4% vs. 10.2%), sepsis/septic shock (15.2% vs. 20.9%), intubation and mechanical ventilation (11.2% vs. 14.6%), prolonged LOS (10.3% vs. 20.6%) and unfavorable discharge (6.9% vs. 12.5%) than those without prior bariatric surgery.ConclusionPrior bariatric surgery predicts a lower risk of life-threatening morbidity and prolonged LOS among adults hospitalized for acute allergic reaction and anaphylaxis. Future prospective studies are warranted to confirm the present findings and reveal underlying mechanisms.Graphical

ScRNA-seq identifies unique macrophage population in murine model of ozone induced asthma exacerbation.

Ozone (O 3 ) inhalation triggers asthmatic airway hyperresponsiveness (AHR), but the mechanisms by which this occurs are unknown. Previously, we developed a murine model of dust mite, ragweed, and aspergillus (DRA)-induced allergic lung inflammation followed by O 3 exposure for mechanistic investigation. The present study used single cell RNA-sequencing for unbiased profiling of immune cells within the lungs of mice exposed to DRA, O 3 , or DRA+O 3 , to identify the components of the immune cell niche that contribute to AHR. Alveolar macrophages (AMs) had the greatest number of differentially expressed genes following DRA+O 3 , most of which were unique to the 2-hit exposure. Following DRA+O 3 , AMs activated transcriptional pathways related to cholesterol biosynthesis, degradation of the extracellular matrix, endosomal TLR processing, and various cytokine signals. We also identified AM and monocyte subset populations that were unique to the DRA+O 3 group. These unique AMs activated gene pathways related to inflammation, sphingolipid metabolism, and bronchial constriction. The unique monocyte population had a gene signature that suggested phospholipase activation and increased degradation of the extracellular matrix. Flow cytometry analysis of BAL immune cells showed recruited monocyte-derived AMs after DRA and DRA+O 3 , but not after O 3 exposure alone. O 3 alone increased BAL neutrophils but this response was attenuated in DRA+O 3 mice. DRA-induced changes in the airspace immune cell profile were reflected in elevated BAL cytokine/chemokine levels following DRA+O 3 compared to O 3 alone. The present work highlights the role of monocytes and AMs in the response to O 3 and suggests that the presence of distinct subpopulations following allergic inflammation may contribute to O 3 -induced AHR.

Diagnosing new-onset asthma in a paediatric clinical trial setting in school-age children.

Asthma is a common chronic disease in children. It is a dynamic condition-symptoms change over time, and the outcome of diagnostic tests can vary. Consequently, evaluating the onset of asthma at a single point in time, perhaps when patients are asymptomatic with limited impairment of the lung function, may result in false diagnostic conclusions. The absence of consistent gold-standard diagnostic criteria in children challenges the ability of any study to ascertain an effect of treatment on asthma prevention. A comprehensive review of the diagnostic criteria used for new-onset asthma in school-age children was conducted based on existing recommendations from published clinical guidance, alongside evidence from paediatric asthma prevention trials. Findings from the review were used to propose suggestions for diagnosing new-onset asthma in future asthma prevention trials. Despite an overall lack of consensus in the published clinical guidance, there are similarities between the various recommendations for diagnosing asthma in children, which typically involve assessing the variable symptoms and supplementing the medical history with objective measures of lung function. For future paediatric asthma prevention trials, we suggest that paediatric clinical trials should use a new-onset asthma definition that incorporates the concepts of "possible", "probable" and "confirmed" asthma. "Possible" asthma would capture self-reported features of chronic symptoms and symptom relief with β2-agonist bronchodilator (suggesting reversibility). "Probable" asthma would include symptom chronicity, self-reported symptom relief with β2-agonist bronchodilator, and objective features of asthma (reversibility or bronchial hyper-responsiveness). A "confirmed" diagnosis would be made only if there is a positive response to controller therapy. These suggestions aim to improve the diagnosis of new-onset childhood asthma in clinical trials, which will be useful in the design and conduct of future paediatric asthma prevention trials.

The integrin receptor beta7 subunit mediates airway remodeling and hyperresponsiveness in allergen exposed mice

BackgroundFibroblast differentiation to a myofibroblast phenotype is a feature of airway remodeling in asthma. Lung fibroblasts express the integrin receptor α4β7 and fibronectin induces myofibroblast differentiation via this receptor.ObjectivesTo investigate the role of the β7 integrin receptor subunit and α4β7 integrin complex in airway remodeling and airway hyperresponsiveness (AHR) in a murine model of chronic allergen exposure.MethodsC57BL/6 wild type (WT) and β7 integrin null mice (β7 -/-) were sensitized (days 1,10) and challenged with ovalbumin (OVA) three times a week for one or 4 weeks. Similar experiments were performed with WT mice in the presence or absence of α4β7 blocking antibodies. Bronchoalveolar (BAL) cell counts, AHR, histological evaluation, soluble collagen content, Transforming growth factor-β (TGFβ) and Interleukin-13 (IL13) were measured. Phenotype of fibroblasts cultured from WT and β7 -/- saline (SAL) and OVA treated mice was evaluated.ResultsEosinophil numbers were similar in WT vs β7-/- mice. Prolonged OVA exposure in β7-/- mice was associated with reduced AHR, lung collagen content, peribronchial smooth muscle, lung tissue TGFβ and IL13 expression as compared to WT. Similar findings were observed in WT mice treated with α4β7 blocking antibodies. Fibroblast migration was enhanced in response to OVA in WT but not β7 -/- fibroblasts. α-SMA and fibronectin expression were reduced in β7-/- fibroblasts relative to WT.ConclusionsThe β7 integrin subunit and the α4β7 integrin complex modulate AHR and airway remodeling in a murine model of allergen exposure. This effect is, at least in part, explained by inhibition of fibroblast activation and is independent of eosinophilic inflammation.

Translational 3D-Cell Culture Model to Assess Hyperoxia Effects on Human Neonatal Airway Epithelial Cells.

The preterm neonatal airway epithelium is constantly exposed to environmental stressors. One of these stressors in neonates with lung disease includes oxygen (O2) tension higher than the ambient atmosphere - termed hyperoxia (>21% O2). The effect of hyperoxia on the airway depends on various factors, including the developmental stage of the airway, the degree of hyperoxia, and the duration of exposure, with variable exposures potentially leading to unique phenotypes. While there has been extensive research on the effect of hyperoxia on neonatal lung alveolarization and airway hyperreactivity, little is known about the short and long-term underlying effect of hyperoxia on human neonatal airway epithelial cells. A major reason for this is the scarcity of an effective in vitro model to study human neonatal airway epithelial development and function. Here, we describe a method for isolating and expanding human neonatal tracheal airway epithelial cells (nTAECs) utilizing human neonatal tracheal aspirates and culturing these cells in air-liquid interface (ALI) culture. We demonstrate that nTAECs form a mature polarized cell-monolayer in ALI culture and undergo mucociliary differentiation. We also present a method for moderate hyperoxia exposure of the cell monolayer in ALI culture using a specialized incubator. Additionally, we describe an assay to measure cellular oxidative stress following hyperoxia exposure in ALI culture using fluorescent quantification, which confirms that moderate hyperoxia exposure induces cellular oxidative stress but does not cause significant cell membrane damage or apoptosis. This model can potentially be used to simulate clinically relevant hyperoxia exposure encountered by neonatal airways in the Neonatal Intensive Care Unit (NICU) and used to study the short and long-lasting effects of O2 on neonatal airway epithelial programming. Studies using this model could be utilized to explore ways to mitigate early-life oxidative injury to developing airways, which is implicated in the development of long-term airway diseases in former premature infants.

The hydro-ethanolic extract of Scoparia dulcis Linn inhibits allergic airway inflammatory responses in murine asthma models

BackgroundInflammatory responses, including airway inflammation, hyper-responsiveness, mucus hyper-secretion, prostaglandins and Th2 cytokines infiltration in the airway submucosa, frequently occur in allergic respiratory disorders. This study sought to investigate the effects of the hydro-ethanolic extract of Scoparia dulcis (SDE) on allergic airway inflammation, airway hyper-responsiveness, goblet cell hyperplasia, mucus hypersecretion, Th2 cytokines and prostaglandin (PG)-D2 using murine asthma models. MethodsAllergic asthma was induced in healthy guinea-pigs, and mice, by exposing them to ovalbumin (OVA) sensitization and challenge, and treatment with either 2 ml/kg normal saline, 10 mg/kg salbutamol, 10 mg/kg prednisolone, 50, 100, or 250 mg/kg of SDE per os. The percentage protection against pre-convulsive dyspnoea after methacholine challenge in OVA-induced asthmatic guinea-pigs was determined for each treatment regime, and histopathological examinations thereafter conducted on the excised lungs. Periodic acid-Schiff staining was also performed to identify goblet cell hyperplasia and mucus hypersecretion in these lung tissues. Lung tissue homogenates and serum from OVA-induced asthmatic mice were also assayed for PGD2, interleukins (IL)-5 and -13 levels using monoclonal antibody-based mouse ELISA kits. ResultsSDE treatments prolonged the time taken for pre-convulsive dyspnoea to occur after methacholine challenge in OVA-induced asthmatic guinea-pigs; indicative of a positive activity against airway hyper-responsiveness. Histopathological studies also showed that SDE significantly inhibited (p ≤ 0.05) pulmonary infiltration of leukocytes, inflammatory cell accumulation, airway smooth muscle thickening and goblet cell hyperplasia. Serum and lung tissue concentrations of PGD2, IL-5 and IL-13, significantly elevated (p ≤ 0.001) following allergic asthma induction in mice, were significantly reduced (p ≤ 0.01) back to within normal levels after SDE treatments. ConclusionThe plant extract exhibited anti-asthmatic and anti-inflammatory properties, as it reduced the severity of allergic inflammation and hyper-reactivity, as well as PGD2 and Th2 cytokines infiltration in the airway; and these effects could be exploited for future management of asthma.

Management of Bronchial Asthma Through Herbo-Mineral Drugs

Ayurveda is ancient system of medicine and a holistic approach to prevent and treat illness by maintaining balance in body and mind to improve your health and vitality. Ayurveda is one of alternative way of treating illness, prevention and management of respiratory disorders. Nowadays respiratory disorders are the major health issue resulting primary cause of death and disability in the world. Asthma is a common respiratory problem increasing globally and affecting approximately 339 million people worldwide and 17.23 million people with an overall prevalence of 2.05% in India. Bronchial asthma is a heterogeneous disease, usually characterized by chronic inflammatory disease of the airway. It is defined by chronic respiratory problem characterized by hyper-responsiveness, inflammation and narrowing of airway resulting in cardinal symptoms cough, chest tightness, dyspnea and wheeze. Tamak swasa closely resembles to bronchial asthma. Swasa roga is major health problem affecting the Pranavaha srotas. According to Acharya Charak tamak swasa is Vata-Kaphaja Vyadhi which is originated from Pithasthan (Amashaya). The treatment of this disease is still unsatisfactory in modern medicine as the use of corticosteroids have many side effects and may lead to medicine dependency. Ayurveda is proven to be a boon for management of asthmatic patients (Tamak swasa). Our Ayurveda classics have explained a lot about signs and symptoms of asthma that has a direct correlation with Tamak swasa. So this is the need of the time that a direct, safe and holistic approach should be established to treat the disease with specific herbomineral formulations as mentioned in our Ayurveda classics.

SGLT2 Inhibitors Empagliflozin and Canagliflozin Ameliorate Allergic Asthma Responses in Mice.

Inhibitors of sodium/glucose cotransporter 2 (SGLT2), such as empagliflozin and canagliflozin, have been widely used to block glucose reabsorption in the proximal tubules of kidneys in patients with diabetes. A meta-analysis suggested that SGLT2 inhibitors are associated with a decreased risk of asthma development. Therefore, we investigated whether SGLT2 inhibitors could suppress allergic asthma. Empagliflozin and canagliflozin suppressed the in vitro degranulation reaction induced by antigens in a concentration-dependent manner in RBL-2H3 mast cells. Empagliflozin and canagliflozin were administered to BALB/c mice sensitized to ovalbumin (OVA). The administration of empagliflozin or canagliflozin significantly suppressed OVA-induced airway hyper-responsiveness and increased the number of immune cells and pro-inflammatory cytokine mRNA expression levels in bronchoalveolar lavage fluid. The administration of empagliflozin and canagliflozin also suppressed OVA-induced histopathological changes in the lungs. Empagliflozin and canagliflozin also suppressed serum IgE levels. These results suggested that empagliflozin and canagliflozin may be applicable for the treatment of allergic asthma by suppressing immune responses.

Brainstem Dbh+ neurons control allergen-induced airway hyperreactivity

Exaggerated airway constriction triggered by repeated exposure to allergen, also called hyperreactivity, is a hallmark of asthma. Whereas vagal sensory neurons are known to function in allergen-induced hyperreactivity1–3, the identity of downstream nodes remains poorly understood. Here we mapped a full allergen circuit from the lung to the brainstem and back to the lung. Repeated exposure of mice to inhaled allergen activated the nuclei of solitary tract (nTS) neurons in a mast cell-, interleukin-4 (IL-4)- and vagal nerve-dependent manner. Single-nucleus RNA sequencing, followed by RNAscope assay at baseline and allergen challenges, showed that a Dbh+ nTS population is preferentially activated. Ablation or chemogenetic inactivation of Dbh+ nTS neurons blunted hyperreactivity whereas chemogenetic activation promoted it. Viral tracing indicated that Dbh+ nTS neurons project to the nucleus ambiguus (NA) and that NA neurons are necessary and sufficient to relay allergen signals to postganglionic neurons that directly drive airway constriction. Delivery of noradrenaline antagonists to the NA blunted hyperreactivity, suggesting noradrenaline as the transmitter between Dbh+ nTS and NA. Together, these findings provide molecular, anatomical and functional definitions of key nodes of a canonical allergen response circuit. This knowledge informs how neural modulation could be used to control allergen-induced airway hyperreactivity.

Nrf2 Deficiency Accelerates IL-17-Dependent Neutrophilic Airway Inflammation in Asthmatic Mice.

Asthma is a heterogeneous disease that can be broadly classified into type 2, which is primarily steroid-sensitive and eosinophilic, and non-type 2, which is primarily steroid-resistant and neutrophilic. While the mechanisms leading to the development of molecular-targeted therapies for type 2 asthma are being elucidated, much remains to be learned about non-type 2 asthma. To investigate the role of oxidative stress in refractory allergic airway inflammation, we compared asthma models generated by immunizing wild-type and nuclear factor erythroid-2-related factor 2 (Nrf2)-deficient mice with the house dust mite antigen. Both asthma models had similar levels of airway inflammation and hyperresponsiveness, but the Nrf2-deficient mice had increased oxidative stress and exacerbated neutrophilic airway inflammation compared with the wild-type mice. Type 2 cytokines and the expression of GATA3, a transcription factor that is important for Th2 cell differentiation, had decreased in Nrf2-deficient mice compared with the wild-type mice, whereas helper T (Th) 17 cytokines and the expression of RORγt, which is important for Th17 cell differentiation, had increased. Furthermore, the neutrophilic airway inflammation caused by Nrf2 deficiency was ameliorated by interleukin (IL)-17 neutralization. We have concluded that the disruption of the Nrf2-mediated antioxidant defense system contributed to the induction of Th17 differentiation and exacerbated allergic neutrophilic airway inflammation.

Degranulation and expression of cytokines were modulated by diazinon in activated mast cells

Diazinon is an organophosphorus (OP) insecticides used in agriculture, home gardening and indoor pest control in Japan. It can activate macrophages and induce pro-inflammatory responses and has been reported to cause airway hyper-reactivity, suggesting the possibility of asthma exacerbation from exposure to OP insecticides. Despite the correlation between insecticide use and the pathogenesis of allergic diseases, there have been no reports on the effects of diazinon on mast cell function. Therefore, in this study, we investigated the effects of diazinon on mast cell function in rat basophilic leukemia (RBL)-2H3 cells. Surprisingly, we found that diazinon inhibited mast cell activation, although the degree of inhibition varied with concentration. Diazinon induced reactive oxygen species (ROS) generation and HO-1 expression at a concentration of 150 µM without affecting cell viability. Diazinon inhibited A23187-mediated degranulation and Tnf and Il4 expression in RBL-2H3 cells but did not affect calcium influx. Suppression of degranulation by diazinon was reversed when the culture supernatant was removed. As a signaling event downstream of calcium influx, diazinon inhibited the phosphorylation of extracellular signal-regulated kinase (ERK) induced by A23187, whereas the phosphorylation of p38 had little effect. IgE cross-linking-mediated degranulation as well as the induction of Tnf and IL4 expression was significantly inhibited by diazinon, while diazinon had little effect on calcium influx. In conclusion, diazinon inhibited mast cell activation, including degranulation and cytokine expression. When evaluating the in vivo effects of diazinon, its potential to inhibit mast cell activation should be considered in the pathophysiology and development of allergic diseases in terms of basic and clinical aspects, respectively, although the effect of diazinon varies depending on the cell type.

Combined Exercise and Diet Induce Airway Hyperreactivity While Reducing Liver Steatosis in Mice with Diet-Induced Obesity.

Obesity is a multi-organ system disease, which is associated with, e.g., a higher prevalence of non-alcoholic fatty liver disease (NAFLD) and asthma. Little is known regarding the effect of obesity-related parameters (including liver integrity) and the respiratory phenotype after a combination of physical activity and diet. Thirty-two C57BL/6 mice were, after 27 weeks of a high fat diet (HFD), randomly assigned to two dietary interventions for three weeks: a HFD or a normal chow diet (NCD). In both dietary groups, half of the animals were subjected to a sub-maximal exercise protocol. Lung function, lung inflammation, liver histology, and metabolic profile were determined. Mice with obesity did not show airway hyperreactivity after methacholine provocation. Sub-maximal exercise with diet (NCD/E) induced a significant reduction in forced expiratory volume in 0.1 s after methacholine provocation. NCD/E had significantly more neutrophils and inflammation (IFN-γ, TNF-α, IL-4, and IL-17F) in bronchoalveolar lavage compared to non-exercising mice on a HFD (HFD/NE). However, more epithelial injury (serum surfactant protein D and IL-33) was seen in HFD/NE. Additionally, hepatic steatosis and fibrosis were reduced by combined diet and sub-maximal exercise. Combining sub-maximal exercise with diet induced airway hyperreactivity and pulmonary inflammation, while body weight, hepatic steatosis, and fibrosis improved.

Monensin Suppresses Multiple Features of House Dust Mite-Induced Experimental Asthma in Mice.

Despite intense efforts to develop efficient therapeutic regimes for asthma, there is a large demand for novel treatment strategies in this disease. Here we evaluated the impact of monensin, a drug with potent anti-mast cell effects, in a mouse model of asthma. Allergic airway inflammation was induced by sensitization of mice with house dust mite (HDM) antigen, and effects of monensin on airway hyperreactivity and inflammatory parameters were studied. Following intraperitoneal administration, monensin did not suppress airway hyperreactivity but was shown to have anti-inflammatory properties, as manifested by reduced eosinophil- and lymphocyte infiltration into the airway lumen, and by suppressed inflammation of the lung tissue. After intranasal instillation, monensin exhibited similar anti-inflammatory effects as seen after intraperitoneal administration. Moreover, intranasally administered monensin was demonstrated to suppress goblet cell hyperplasia, and to cause a reduction in the expression of genes coding for key inflammatory markers. Further, monensin blocked mast cell degranulation in the airways of allergen-sensitized mice. Together, this study reveals that monensin has the capacity to suppress key pathological events associated with allergic airway inflammation.

Obesity-associated Airway Hyperresponsiveness: Mechanisms Underlying Inflammatory Markers and Possible Pharmacological Interventions.

Obesity is rapidly becoming a global health problem affecting about 13% of the world's population affecting women and children the most. Recent studies have stated that obese asthmatic subjects suffer from an increased risk of asthma, encounter severe symptoms, respond poorly to anti-asthmatic drugs, and ultimately their quality-of-life decreases. Although, the association between airway hyperresponsiveness (AHR) and obesity is a growing concern among the public due to lifestyle and environmental etiologies, however, the precise mechanism underlying this association is yet to establish. Apart from aiming at the conventional antiasthmatic targets, treatment should be directed towards ameliorating obesity pathogenesis too. Understanding the pathogenesis underlying the association between obesity and AHR is limited, however, a plethora of obesity pathologies have been reported viz., increased pro-inflammatory and decreased anti-inflammatory adipokines, depletion of ROS controller Nrf2/HO-1 axis, NLRP3 associated macrophage polarization, hypertrophy of WAT, and down-regulation of UCP1 in BAT following down-regulated AMPKα and melanocortin pathway that may be correlated with AHR. Increased waist circumference (WC) or central obesity was thought to be related to severe AHR, however, some recent reports suggest body mass index (BMI), not WC tends to exaggerate airway closure in AHR due to some unknown mechanisms. This review aims to co-relate the above-mentioned mechanisms that may explain the copious relation underlying obesity and AHR with the help of published reports. A proper understanding of these mechanisms discussed in this review will ensure an appropriate treatment plan for patients through advanced pharmacological interventions.