FEV1 % predicted vs % baseline in assessing bronchial hyperreactivity.

In this investigation we have used a mouse model containing certain phenotypic characteristics consistent with asthma and IL-4- and CD40-deficient mice to establish the role of this cytokine and allergen-specific immunoglobulins in the initiation of airways hyperreactivity and morphological changes to the airways in responses to aeroallergen challenge. Sensitization and aerosol challenge of mice with ovalbumin resulted in a severe airways inflammatory response which directly correlated with the induction of extensive airways damage and airways hyperreactivity to beta-methacholine. Inflammatory infiltrates were primarily characterized by the presence of CD4+ T cells and eosinophils. In IL-4-deficient mice, the recruitment of airways eosinophils was impaired, but not abolished in response to aeroallergen. Moreover, the characteristic airways damage and hyperreactivity normally resulting from allergen inhalation were not attenuated. Induction of these structural and functional changes to the airways occurred in the absence of ovalbumin-specific IgE and IgG1, but IgG2a and IgG3 were detected in the sera of IL-4-deficient mice. CD4+ T cells isolated from both wild-type and IL-4-deficient mice given ovalbumin produced significant levels of IL-5 after in vitro stimulation. Treatment of IL-4-deficient mice with anti-IL-5 mAb before aeroallergen challenge abolished blood and airways eosinophilia, lung damage, and airways hyperreactivity. These results indicate that IL-4 is not essential for the development of IL-5-producing CD4+ T cells or for the induction of eosinophilic inflammation and airways damage and hyperreactivity. In response to sensitization and aerosol challenge, CD40-deficient mice did not produce ovalbumin-specific IgE, IgG isotypes, or IgA, and airways inflammation and hyperreactivity were not attenuated. Our results suggest that allergic airways disease can occur via pathways which operate independently of IL-4 and allergen-specific immunoglobulins. Activation of these pathways is intimately associated with IL-5 and eosinophilic inflammation. Such pathways may play a substantive role in the etiology of asthma.

Background: The aim was to optimize antigen challenge for induction of airway hyperresponsiveness (AHR) and inflammation in BALB/c mice sensitized to ovalbumin (OVA). Comparisons were made between mice challenged with OVA either as an aerosol or intranasally. The protocol that induced maximal AHR in BALB/c mice was thereafter tested in C57BL/6 mice. Method: Methacholine responsiveness was measured using the flexiVent® system to assess AHR. Inflammatory responses were investigated by histology and cell counts in bronchoalveolar lavage (BAL) fluid. Results: 48 h after challenge with 1 or 6% OVA aerosols, there were similar increments in AHR and BAL cells, predominantly eosinophils. When comparing the effect of 1% OVA aerosol on AHR and cell infiltration at 24 and 48 h after challenge, the responses were similar. At 24 h, intranasal OVA administration (20–200 µg) caused a dose-dependent increase in AHR. BAL cells were increased by all intranasal OVA doses and to a greater extent than after 1% OVA aerosol challenge but without any dose dependency. Histological examination confirmed that there was an increase of eosinophils in lung tissue following either challenge. In C57BL/6 mice, baseline tissue elastance was the only functional outcome that was increased after intranasal OVA challenge. Even though the AHR response was negligible in C57BL/6 mice, a similar infiltration of BAL cells was observed in both strains. Conclusion: Intranasal challenge was more effective than aerosol challenge at inducing both AHR and airway inflammation in BALB/c mice. Although intranasal challenge caused airway inflammation in C57BL/6 mice, this strain is not optimal for studying AHR.

The objective of the study is to investigate the protective effect of Ginkgolide B on house dust mite (HDM)-sensitized asthmatic mice and its potential mechanism involving the TLR4/NF-κB pathway. In HDM-induced asthmatic mice, we administered varying doses of Ginkgolide B. We evaluated airway hyperresponsiveness and the expectorant properties of Ginkgolide B. Changes in inflammatory infiltration, goblet cell proliferation, and airway fibrosis were detected with HE, PAS, and Masson staining. We analyzed the Th1 and Th2 cell numbers and their secreted cytokine levels. In a more in-depth study, we administered lentiviruses that overexpressed and knocked down TLR4, while also treating with Ginkgolide B. Subsequently, we conducted experiments on airway hyperresponsiveness, HE and PAS staining, and flow cytometry for detecting the Th1 and Th2 cell numbers. HDM-sensitized asthmatic mice exhibited high airway reactivity and severe inflammatory response. After treatment with Ginkgolide B, airway hyperresponsiveness significantly improved; inflammation, airway tissue fibrosis, and goblet cell proliferation were reduced, while airway secretions decreased and expectorant ability was enhanced. In addition, Ginkgolide B effectively inhibited the shift of Th1/Th2 immune balance to Th2 in asthmatic mice. In-depth mechanistic research has found that the aforementioned effects of Ginkgolide B were related to the TLR4/NF-κB pathway. Ginkgolide B inactivated the TLR4/NF-κB pathway, restored the Th2/Th1 immune balance, and alleviated airway hyperresponsiveness and the inflammatory response. Our research showed that Ginkgolide B effectively treated HDM-sensitized asthma in mice by inhibiting the TLR4/NF-κB pathway, restoring Th1/Th2 balance, and alleviating airway inflammation and hyperresponsiveness.

Lignosus rhinocerotis Cooke. (L. rhinocerotis) is a medicinal mushroom traditionally used in the treatment of asthma and several other diseases by the indigenous communities in Malaysia. In this study, the effects of L. rhinocerotis on allergic airway inflammation and hyperresponsiveness were investigated. L. rhinocerotis extract (LRE) was prepared by hot water extraction using soxhlet. Airway hyperresponsiveness (AHR) study was performed in house dust mite (HDM)-induced asthma in Balb/c mice while airway inflammation study was performed in ovalbumin (OVA)-induced asthma in Sprague-Dawley rats. Treatment with different doses of LRE (125, 250 and 500 mg/kg) significantly inhibited AHR in HDM-induced mice. Treatment with LRE also significantly decreased the elevated IgE in serum, Th2 cytokines in bronchoalveolar lavage fluid and ameliorated OVA-induced histological changes in rats by attenuating leukocyte infiltration, mucus hypersecretion and goblet cell hyperplasia in the lungs. LRE also significantly reduced the number of eosinophils and neutrophils in BALF. Interestingly, a significant reduction of the FOXP3+ regulatory T lymphocytes was observed following OVA induction, but the cells were significantly elevated with LRE treatment. Subsequent analyses on gene expression revealed regulation of several important genes i.e. IL17A, ADAM33, CCL5, IL4, CCR3, CCR8, PMCH, CCL22, IFNG, CCL17, CCR4, PRG2, FCER1A, CLCA1, CHIA and Cma1 which were up-regulated following OVA induction but down-regulated following treatment with LRE. In conclusion, LRE alleviates allergy airway inflammation and hyperresponsiveness, thus suggesting its therapeutic potential as a new armamentarium against allergic asthma.

Recent epidemiological studies demonstrated that bronchial hyperresponsiveness (BHR) is an independent predictor of COPD risk and the second most important risk factor for COPD after smoking. Aim: The aim of the study was to assess factors associated with BHR in COPD patients. Methods: 139 COPD patients (GOLD II) 119 males and 20 females meanage of 58 yrs were studied. Medical history, clinical features and BHR were analyzed. Criteria of BHR was provocative dose of methacholine (PD20) <0,471 mg. Results: BHR was revealed in 68 % patients with COPD. Age of patients did not differ between subjects with BHR and without BHR. The frequency and level of BHR were significantly different according to gender. Among COPD women BHR was higherand was revealed in 90% of cases compared with 65% of men (p=0,035): OR=4,9 (1,6 30,0 kg/m2) was 2 times higher among patients with BHR (38,9% vs. 20,5%, p = 0,034) in comparison to patients without BHR: OR=3,4 (1,3<OR< 5,4). Among patients with BHR and history of smoking over 35 pack/years, the median PD20 of methacholine was 1,9 times lower than patients with less 35 pack/years (p=0,037): OR=7,4 (2,0<OR<8,3). There were no differences in the severity of BHR when compared PD20 ofcurrent smokers and ex-smokers: OR=1,5 (0,6 <OR< 3,9). Conclusions: Thus, the most significant factors for the BHR formation in COPD patients are female sex and overweight, including obesity. An intensity of smoking influenced on a degree of BHR in COPD patients.

Beyond our Pages

Effective treatment for severe corticosteroid refractory asthma is a significant unmet clinical need. It affects only a small percent of the asthmatic population but accounts for a disproportionate use of healthcare resources. The aim was to study IL-13 transgenic mice to test the hypothesis that a subset of IL-13 mediated airway responses are corticosteroid-unresponsive and contribute to ongoing airways symptoms. IL-13 expression in the lungs was induced using Doxycycline in Ccsp-rtTA/Otet-Il-13 (Ccsp/Il-13) mice. Where indicated, mice received intra-peritoneal injections of 3mg/kg Dexamethasone for 3-7 days. Lungs were analysed for airway hyperreactivity and inflammation. Compared to controls, Ccsp/Il-13 mice showed significantly increased airway hyperresponsiveness (AHR) to methacholine and immunohistochemistry revealed increased bronchial smooth muscle and goblet cell metaplasia. The bronchoalveolar lavage fluid contained mixed eosinophilic and neutrophilic inflammation, but neutrophils predominated. Characteristic Th2-responsive genes as well as genes associated with Th17 responses were significantly elevated. Treatment with steroids did not abrogate AHR, even though eosinophilia and the ‘Th2’ gene signature were significantly reduced. Neutrophils and the ‘Th17’ signature remained elevated. Although IL-13 promotes eosinophilic airways disease, it can also drive corticosteroid refractory inflammation characterised by persistent neutrophilia, Th17 cytokines and maintenance of AHR. The Ccsp/Il-13 mouse may be a useful model for dissecting the molecular pathways and mechanisms associated with predominant neutrophilic, corticosteroid refractory airway disease.

T H1-mediated airway hyperresponsiveness independent of neutrophilic inflammation

BLT2 is a low-affinity receptor for leukotriene B(4) (LTB(4)), a potent lipid mediator of inflammation generated from arachidonic acid via the 5-lipoxygenase pathway. Unlike BLT1, a high-affinity receptor for LTB(4), no clear physiological function has yet been identified for BLT2, especially with regard to the pathogenesis of asthma. The aim of this study was to investigate whether BLT2 plays a role in the pathogenesis of asthma. A murine model of allergic asthma was used to evaluate the role of BLT2 in ovalbumin-induced airway inflammation and airway hyperresponsiveness. The levels of BLT2 mRNA and its ligand, LTB(4), in the lung airway were highly elevated after ovalbumin challenge, and down-regulation of BLT2 with antisense BLT2 oligonucleotides markedly attenuated airway inflammation and airway hyperresponsiveness. Further analysis, aimed at identifying mediators downstream of BLT2, revealed that BLT2 activation led to elevation of reactive oxygen species and subsequent activation of NF-kappaB, thus inducing the expression of vascular cell adhesion molecule-1, which is known to be involved in eosinophil infiltration into the lung airway. Together, our results suggest that BLT2 plays a pivotal, mediatory role in the pathogenesis of asthma, acting through a "reactive oxygen species-NF-kappaB"-linked inflammatory signaling pathway.

This review evaluates the role of IL–5 and IL–5–mediated eosinophil airway infiltration in the development of allergen–driven airway hyperresponsiveness. It discusses the structure and function of IL–5 and its receptor and the mechanisms of IL–5–triggered eosinophil accumulation and inflammation of the airways. New research data from murine models of airway inflammation and hyperresponsiveness utilizing different modes of sensitization to allergen and anti–IL–5 antibody or IL–5–deficient knock–out mice underscore the outstanding role of this cytokine in the pathogenesis of bronchial asthma. This review identifies possible directions for future treatment of airway hyperresponsiveness and concludes that targeting IL–5–driven inflammatory responses may be most beneficial for a novel therapy in bronchial asthma.

BackgroundAsthma is characterized by a chronic inflammatory process involving high numbers of inflammatory cells and mediators which have multiple inflammatory effects on the airway. Interferon (IFN)-alpha, which is used widely for treating chronic hepatitis C, is reported to have an effect on patients with Churg-Strauss syndrome. Therefore, it may also be suitable for patients with severe asthma.ObjectiveWe studied the effect of IFN-alpha on airway eosinophilia in a guinea pig model of asthma and the expression of adhesion molecules on human eosinophils and vascular endothelial cells.MethodsAfter antigen challenge, airway hyperresponsiveness and airway eosinophilia were measured in a guinea pig asthma model with or without airway IFN-alpha administration. Expression of adhesion molecules on eosinophils and cultured human umbilical vein endothelial cells (HUVECs) was also evaluated with or without IFN-alpha.ResultsIFN-alpha inhibited eosinophil recruitment into the tracheal wall and improved airway hyperresponsiveness in sensitized guinea pigs. IFN-alpha also significantly suppressed IL-1 beta-induced intercellular adhesion molecule-1 (ICAM-1) expression on HUVECs. However, IFN-alpha did not suppress platelet-activating factor-induced macrophage antigen-1 expression on human eosinophils. IFN-alpha significantly inhibited eosinophil adhesion to IL-1 beta-induced HUVECs and migration through IL-1 beta induced HUVECs.ConclusionThe findings suggest that the modulation of ICAM-1 in lung with pre-existing inflammation following treatment with IFN-alpha may be a novel and selective treatment for control of chronic airway inflammation and hyperresponsiveness associated with asthma.

Attenuated airways inflammation and remodeling in IL-37a and IL-37b transgenic mice with an ovalbumin-induced chronic asthma

Histamine has a variety of airway actions and is considered to be an important mediator in asthma. This study examined the role of endogenous histamine in allergic airway eosinophil recruitment and hyperresponsiveness using L-histidine decarboxylase gene knockout mice. Histamine levels of the airways in L-histidine decarboxylase knockout mice were largely diminished compared with wild-type mice. Inhalation challenge with ovalbumin (OVA) in OVA-sensitized wild-type mice caused eosinophil accumulation in the lung as well as airway hyperresponsiveness to methacholine 3 days after the challenge. The eosinophil recruitment was significantly reduced in the knockout mice. In the bone marrow, the proliferation of eosinophils was enhanced after OVA challenge in the wild-type mice; however, the proliferation was significantly reduced in the knockout mice. The induction of P-selectin in the lung after OVA challenge was also inhibited in the knockout mice. In contrast, airway hyperresponsiveness was not suppressed in the knockout mice. These results suggest that endogenous histamine is involved in the accumulation of eosinophils into the airways after allergic challenge, possibly acting in the bone marrow and producing P-selectin in the airways. Furthermore, allergen-induced airway hyperresponsiveness appeared to occur independently of airway eosinophilia in our present model.

Mesenchymal stem cells alleviate oxidative stress–induced mitochondrial dysfunction in the airways

Aim. To compare the nature and degree of influence of different types of airway hyperresponsiveness (AHR) on the general and specific quality of life (QoL) of patients with asthma and control over the disease.Materials and methods. 234 patients with mild-to-moderate asthma, aged from 18 to 60 years old, were interviewed and examined. Depending on the presence of one or another type of AHR, 4 groups were formed: group 1 included 60 patients with cold AHR, group 2 – 75 patients with hypoosmotic AHR, group 3 – 35 patients with hyperosmotic AHR, group 4 – 64 patients with exercise-induced bronchoconstriction (EIB). QoL and the state of the emotional sphere were assessed using the SF-36, AQLQ, HADS questionnaires. The level of asthma control was determined using the ACT questionnaire. Lung function was assessed by spirometry.Results. When comparing QoL between groups, statistical differences were obtained for most of the SF-36 scales, with the exception of the domains “Role Physical” (RP) and “Bodily Pain” (BP), and their presence and significance varied depending on the types of AHR being compared. The lowest QoL indices were found in group 1 of patients with cold AHR according to the domains “Physical Activity” (PA), RP, BP, and “Role Emotional” (RE). The lowest indices for the domains “General Health” (GH), “Vitality” (V) and “Mental health” (MH) were found in the respondents of the 2nd group. Most of the highest QoL indicators in the compared groups were found in patients of group 4 with EIB in the domains PA, RP, V, RE, and MH. When carrying out a comparative analysis, the maximum number of significant differences was found between the groups with cold AHR and EIB. A comparative study of QoL using a special AQLQ questionnaire showed the lowest indices for the “Activity” and “Symptoms” domains in groups 1 and 2 of asthma patients. In addition, in group 1, the minimum QoL values were recorded for the “General QoL” domain (3.6±0.2 points), and in group 2, for the “Environment” domain (2.9±0.3 compared with 3.9±0.2 points in group 3, p&lt;0.01).Conclusion. This study has demonstrated the multifaceted effect of AHR on health-related QoL, dependent on sensitivity to a particular physical stimulus and the season of maximum trigger action. The subjective assessment of psychosocial functioning is most differentiated according to the GH domain of the SF-36 questionnaire. The greatest negative impact on the QoL indices is exerted by the cold and hypoosmotic AHR, the least – by the EIB. The assessment of QoL allows to get a full picture of the perception of the patient's health level at the moment and in the given conditions.