Inhibition of antigen-induced airway hyperresponsiveness by a thromboxane synthetase inhibitor (OKY-046) in allergic dogs

To determine the role of thromboxane A2 in the airway hyperresponsiveness induced by antigen challenge, we studied the effect of a thromboxane synthetase inhibitor, OKY-046, i.e., sodium (E)-3-[4-(1-imidazolylmethyl)-phenyl]-2-propanoate, in 6 ragweed-sensitized dogs. Airway responsiveness was assessed with dose-response curves of acetylcholine aerosol versus total pulmonary resistance before and 6 and 24 h after inhalation with ragweed antigen. This procedure was repeated in each dog during intravenous infusion of OKY-046 (100 micrograms/kg/min). OKY-946 did not alter the acute increase in total pulmonary resistance after antigen. At 6 h, there was a 7-fold increase in airway responsiveness, an effect that was prevented by OKY-046 (p less than 0.001). At 24 h, 18 h after OKY-046 was stopped, hyperresponsiveness was still significantly inhibited. OKY-046 did not alter the influx of neutrophils recovered by bronchoalveolar lavage performed at 6 h after antigen challenge. Antigen-induced airway hyperresponsiveness in dogs may depend upon the thromboxane A2 generation from inflammatory cells (e.g., neutrophils).     

Inhibition of complement activation decreases airway inflammation and hyperresponsiveness

Studies in murine models have suggested the involvement of the complement anaphylatoxins (C3a and C5a) in the development of allergic asthma. We investigated the effects of inhibiting complement activation after sensitization but before allergen challenge on the development of allergic airway inflammation and airway hyperresponsiveness. To prevent complement activation, we used a recombinant soluble form of the mouse membrane complement inhibitor complement receptor-related gene y (Crry) fused to the IgG1 hinge, CH2 and CH3 domains (Crry-Ig), which has decay-accelerating activity for both the classic and alternative pathways of complement as well as cofactor activity for factor I-mediated cleavage of C3b and C4b. C57BL/6 mice were sensitized (Days 1 and 14) and challenged (Days 24-26) with ovalbumin. Crry-Ig was administered after allergen sensitization either as an intraperitoneal injection or by nebulization before allergen challenge. Crry-Ig significantly prevented the development of airway hyperresponsiveness, decreased airway and lung eosinophilia as well as the numbers of lung lymphocytes, decreased levels of interleukin (IL)-4, IL-5, and IL-13 in bronchoalveolar lavage fluid and decreased serum ovalbumin-specific IgE and IgG1. These results suggest that prevention of complement activation may have a therapeutic role in the treatment of allergic airway inflammation and asthma in sensitized individuals.     

Inhibition of phosphodiesterase 4 attenuates airway hyperresponsiveness and airway inflammation in a model of secondary allergen challenge

We compared for the first time the therapeutic potential of a specific phosphodiesterase 4 (PDE4) inhibitor, rolipram, with anti-VLA-4 and anti-IL-5 in a model of secondary allergen exposure of previously sensitized and challenged mice. To address these issues, mice were sensitized and challenged with ovalbumin (OVA) (primary challenge). Six weeks later, sensitized/challenged mice were reexposed to OVA (secondary challenge) and airway response (resistance [RL] and dynamic compliance [Cdyn]) to inhaled methacholine was monitored. After secondary OVA challenge, RL significantly increased as did the number of lung inflammatory cells and IL-4 and IL-5 production in bronchoalveolar lavage fluid (BALF). Administration of rolipram, in a dose-dependent manner, significantly prevented both changes in RL and Cdyn, as well as eosinophil, lymphocyte, and neutrophil accumulation in the BALF; IL-4 and IL-5 levels in BALF were also significantly reduced. In contrast, treatment with anti-VLA-4 and anti-IL-5 only prevented changes in RL and eosinophil numbers and IL-5 production in BALF. Further, goblet cell hyperplasia was suppressed only by treatment with rolipram. None of the treatments affected OVA-specific antibody levels. These studies confirm that IL-5 dependent eosinophilic inflammation plays an essential role in the development of certain aspects of airway function after rechallenge of sensitized mice and that lymphocytes and neutrophils are also important in the development of altered airway function. The use of agents that inhibit PDE4 may have an important role in the treatment of asthma in previously sensitized mice.     

Inhibition of airway hyperresponsiveness and pulmonary inflammation by roflumilast and other PDE4 inhibitors

Roflumilast is an oral, once-daily phosphodiesterase 4 (PDE4) inhibitor with anti-inflammatory activity. We compared the anti-inflammatory effects of roflumilast with those of PDE4 inhibitors rolipram, piclamilast, and cilomilast in ovalbumin (OVA)-sensitized and challenged Brown-Norway rats. Animals were treated orally 1h before OVA challenge with roflumilast (0.3, 1.0, and 3.0mg/kg), rolipram (0.8, 2.8, and 8.3mg/kg), piclamilast (10.0, 20.0, and 30.0mg/kg), or cilomilast (10.3, 34.3, and 103.0mg/kg). Airway hyperresponsiveness (AHR) against adenosine was investigated by measuring airway resistance 200min after OVA challenge. Subsequently, neutrophil influx and tumor necrosis factor-alpha (TNF-alpha) release in the lungs were determined by bronchoalveolar lavage. Direct bronchodilation at the time point of AHR assessment by PDE4 inhibitors was examined in serotonin-challenged animals. Evaluation of neutropenic animals or treatment with anti-TNF-alpha antibody revealed that AHR was independent of neutrophil accumulation or TNF-alpha release. Roflumilast (50% inhibitory dose [ID(50)]=1.5mg/kg) inhibited AHR 3-, 16-, and 27-fold more potently than rolipram, piclamilast, and cilomilast, respectively. Likewise, roflumilast was a more potent inhibitor of neutrophil influx (ID(50)=0.9mg/kg) than rolipram (ID(50)=6.9mg/kg), piclamilast (ID(50)=28.1mg/kg), or cilomilast (ID(50)=37.7mg/kg). Roflumilast, rolipram, and piclamilast-but not cilomilast-suppressed OVA-induced TNF-alpha release in a dose-dependent manner. Roflumilast (ID(50)=0.9mg/kg) exhibited 9- and 23-fold more potent inhibition of TNF-alpha release than rolipram and piclamilast, respectively. Roflumilast did not inhibit serotonin-induced bronchoconstriction 4.5h after administration, suggesting that inhibition of AHR by roflumilast results from anti-inflammatory, not bronchodilatory, effects. This study suggests that roflumilast has anti-inflammatory action and provides rationale for the investigation of roflumilast in asthmatic patients.     

Inherent and antigen-induced airway hyperreactivity in NC mice

In order to clarify the airway physiology of NC mice, the following experiments were carried out. To investigate inherent airway reactivity, we compared tracheal reactivity to various chemical mediators in NC, BALB/c, C57BL/6 and A/J mice in vitro. NC mice showed significantly greater reactivity to acetylcholine than BALB/c and C57BL/6 mice and a reactivity comparable to that of A/J mice, which are known as high responders. Then, airway reactivity to acetylcholine was investigated in those strains in vivo. NC mice again showed comparable airway reactivity to that seen in A/J mice and a significantly greater reactivity than that seen in BALB/c and C57BL/6 mice. To investigate the effects of airway inflammation on airway reactivity to acetylcholine in vivo, NC and BALB/c mice were sensitized to and challenged with antigen. Sensitization to and challenge with antigen induced accumulation of inflammatory cells, especially eosinophils, in lung and increased airway reactivity in NC and BALB/c mice. These results indicate that NC mice exhibit inherent and antigen-induced airway hyperreactivity. Therefore, NC mice are a suitable strain to use in investigating the mechanisms underlying airway hyperreactivity and such studies will provide beneficial information for understanding the pathophysiology of asthma.     

嗜酸粒细胞性气道炎症与气道高反应性

为了研究气道嗜酸粒细胞聚集和激活对气道反应性的影响，应用多粘菌素Ｂ豚鼠点鼻建立嗜酸粒细胞性气道炎症的动物模型。结果表明，嗜酸粒细胞聚集本身不引起气道高反应性（ＡＨＲ），而已聚集的嗜酸粒细胞激活在ＡＨＲ发生上起重要作用。提示嗜酸粒细胞激活可能是哮喘发作的重要触发因素。     

Comparative effects of a fixed combination of reproterol hydrochloride and disodium cromoglycate with each agent alone on antigen-induced airway responses in sheep

The purpose of this study was to compare the effectiveness of an eight day treatment with clinically relevant doses of a fixed combination of the beta 2 mimetic reproterol hydrochloride and disodium cromoglycate with each agent given alone against antigen-induced early (EAR) and late airway responses (LAR) as well as post-antigen-induced airway hyperresponsiveness (AHR) in allergic sheep. Animals were treated in a randomized fashion with either the inhaled combination (n = 6), reproterol hydrochloride alone (n = 6), disodium cromoglycate alone (n = 6), or placebo (n = 8). Treatments (two puffs from a metered dose inhaler) were given three times a day for 7 days and once on the 8th day 1 h before airway challenge with Ascaris suum antigen. In the placebo trial, antigen challenge resulted in EAR and LAR as measured by increases in specific lung resistance; these changes were followed 24h later by AHR to inhaled carbachol. With respect to the placebo trial, treatment with reproterol hydrochloride reduced the EAR (P < 0.05) and blocked the LAR (P < 0.05), but had no effect on the post-challenge AHR. Treatment with disodium cromoglycate also reduced the EAR (P < 0.05), blocked the LAR (P < 0.05), and blocked the post-antigen-induced AHR (P < 0.05). Treatment with the fixed combination reduced the EAR (P < 0.05), blocked the LAR (P < 0.05), and blocked the post-antigen-induced AHR (P < 0.05). Comparison of the different agents indicated that the fixed combination gave significantly increased protection against the EAR than either agent alone, gave slightly better (P < 0.05) protection against the late response than cromolyn sodium and gave better protection against post-antigen-induced AHR than reproterol hydrochloride alone. These results suggest that a fixed combination of a beta 2-mimetic and disodium cromoglycate provides some increased protection against antigen-induced airway responses when compared to either agent alone in a controlled laboratory setting.     

布地奈德上调支气管哮喘小鼠肺组织IDO、抑制气道炎症和气道高反应性的研究

目的 研究布地奈德对急性支气管哮喘(简称哮喘)模型小鼠肺组织吲哚胺-2,3双加氧酶(IDO)表达、气道炎症和气道高反应性的干预作用.方法 18只SPF级BALB/c小鼠随机分为正常组、哮喘组、布地奈德组.卵白蛋白(OVA)致敏和激发建立哮喘模型.末次激发24 h后,测定气道对乙酰胆碱的反应性,HE染色观察气道炎症细胞浸润,ELISA法检测血清总IgE、OVA特异性IgE(OVA-sIgE)以及支气管肺泡灌洗液(BALF) Th2细胞因子(IL-4和IL-13).Western blot检测肺组织IDO蛋白表达.结果 正常组小鼠气道阻力随乙酰胆碱浓度增加仅轻度增加,哮喘组气道阻力较正常组显著增高,布地奈德组气道阻力较哮喘组显著下降(P＜0.05);哮喘组血清总IgE和OVA-sIgE、BALF炎症细胞总数和嗜酸粒细胞分类计数、Th2细胞因子水平较正常组显著增高,布地奈德组炎症指标较哮喘组显著降低(P＜0.05);哮喘组肺组织IDO)较正常组显著下降,布地奈德组肺组织IDO较哮喘组显著增高(P＜0.05).结论 布地奈德抑制急性哮喘模型气道炎症和气道高反应性,可能与上调肺组织IDO有关.     

Inhibition of mitogen- and antigen-induced lymphocyte blastogenesis by herpes simplex virus.

Lymphocytes were separated from peripheral blood of adult human donors by Ficoll-Hypaque gradient centrifugation and cultured in the presence of nonspecific mitogens (phytohemagglutinin[PHA] and concanavalin A) or specific microbial anatigens (herpes simplex virus [HSV], mumps virus, streptococcal enzymes, and Candida albicans). Exposure of lymphocyte cultures to infectious HSV resulted in almost complete inhibition of blastogenesis ([3/H]thymidine uptake) induced by each of the mitogens and antigens, a finding which suggests that a common mechanism may underlie the inhibitory effect. Several characteristics of the effect of virus on blastogenesis were noted: (1) virus inactivated by heat or ultraviolet irradiation was ineffective; (2) inhibition (is greater than 90%) was greatest in cultures exposed to HSV on or before the addition of PHA; (3) lymphocyte preparations washed free of HSV continued to be refractory to stimulation, an observation indicating that the presence of unabsorbed virions or viral products was not essential; and (4) inhibition was independent of the cell donor's state of humoral immunity to HSV.     

Modulation of inflammation and response to dexamethasone by Annexin 1 in antigen-induced arthritis

OBJECTIVE: Annexin 1 (Anx-1) is a putative mediator of the antiinflammatory actions of glucocorticoids (GCs). This study investigated the role of Anx-1 in experimental arthritis and in GC-mediated inhibition of inflammation, using antigen-induced arthritis (AIA) in Anx-1 knockout (Anx-1(-/-)) mice. METHODS: Arthritis was induced by intraarticular injection of methylated BSA (mBSA) in mice preimmunized with mBSA. Disease was assessed after 7 days by histologic examination of the knee joints. Serum levels of anti-mBSA IgG were determined by enzyme-linked immunosorbent assay. Cytokine messenger RNA (mRNA) expression was detected by real-time polymerase chain reaction. RESULTS: A significant exacerbation of arthritis was observed in the Anx-1(-/-) mice compared with wild-type (WT) mice. This was associated with increased mRNA expression of synovial interleukin-1 beta, tumor necrosis factor alpha, interleukin-6, and macrophage migration inhibitory factor. Dexamethasone significantly reduced the histologic severity of synovitis and bone damage in the WT mice, but exerted no inhibitory effects in the Anx-1(-/-) mice, and also significantly reduced the serum levels of anti-mBSA IgG and the numbers of peripheral blood neutrophils and lymphocytes in WT mice, but had no such effect in Anx-1(-/-) mice. CONCLUSION: Anx-1 exerts endogenous antiinflammatory effects on AIA via the regulation of cytokine gene expression, and also mediates the antiinflammatory actions of dexamethasone in AIA.     

Regulation of inflammation by airway smooth muscle

Inflammatory mediators play a critical role in the pathogenesis of chronic airway diseases and facilitate the recruitment, activation, and trafficking of inflammatory cells in the airways. Compelling evidence now shows that airway smooth muscle expresses adhesion molecules and secretes inflammatory mediators. Airway myocytes also express a repertoire of immunomodulatory proteins such as Toll-like receptors, chemokines, and cytokines. The underlying mechanisms by which these molecules modulate airway inflammation and the physiological consequences of these molecules are now being elucidated, suggesting that airway smooth muscle plays an important role in orchestrating and perpetuating airway inflammation, remodeling, and fibrosis in chronic airway diseases.     

兴安杜鹃挥发油抗气道变应性炎症的研究

目的 探讨兴安杜鹃挥发油对小鼠气道变应性炎症的治疗。方法 对昆明小鼠采用超声雾化吸入１％卵清蛋白生理盐水致敏,建立小鼠气道变应性炎症模型,检测并比较各组间肺组胺浓度及肺组织病理学变化。结果 治疗组模型组肺组胺浓度差异显著（Ｐ〈０．０５）,肺组织病理学变化表明,治疗组模型组有明显恢复,与正常对照组接近。结论 兴安杜鹃挥发油具有明显的抗炎、平喘作用。     

Relationships among bacteria, upper airway, lower airway, and systemic inflammation in COPD

STUDY OBJECTIVE: The upper and lower airways are continuous. While upper airway symptoms are common in COPD patients, with accumulating evidence to suggest increased nasal inflammation, the relationships among upper airway, lower airway, and systemic inflammatory indexes have not been studied. We aimed to confirm that there is heightened nasal inflammation in COPD patients, to test the hypothesis that the degree of upper airway inflammation relates to the degree of lower airway inflammation, and to investigate the underlying associations with bacterial carriage and the systemic inflammatory response. DESIGN: Prospective cohort study. SETTING: Outpatient Department, London Chest Hospital, London, UK. PARTICIPANTS: Forty-seven patients with COPD and 12 control subjects of similar age, sex, and smoking status. MEASUREMENTS: Serum, nasal wash fluid, and sputum samples were obtained from 47 stable patients with COPD for the analysis of inflammatory indexes and bacterial colonization. Nasal wash fluid specimens were obtained from 12 control subjects. RESULTS: COPD patients had an increased nasal interleukin (IL)-8 concentration compared to control subjects (difference, 97.2 pg/mL; p = 0.009). The nasal IL-8 concentration in COPD patients correlated with that in sputum (r = 0.30; p = 0.039). In both the upper and lower airways of patients with COPD, the IL-8 concentration was associated with indexes of bacterial colonization. Patients colonized with a sputum potentially pathogenic microorganism had a higher total nasal bacterial load (difference, 1.5 log cfu/mL; p = 0.016). We did not find significant relationships between the degree of upper or lower airway inflammation, or bacterial carriage, and the systemic inflammatory response. CONCLUSIONS: COPD is associated with an increased nasal concentration of the neutrophil chemoattractant protein IL-8, the degree of which reflects that present in the lower airway. A relationship between lower airway bacterial colonization, postnasal drip, and higher nasal bacterial load may suggest a mechanism underlying this finding. This study is the first to report a correlation between the degree of upper and lower airway inflammation in COPD.     

Gastro-oesophageal reflux, eosinophilic airway inflammation and chronic cough

Background and objective: Patients with eosinophilic airway inflammation (EAI) often show a therapeutic response to corticosteroids. Non‐invasive methods of diagnosing EAI are potentially useful in guiding therapy, particularly in conditions such as chronic cough, for which corticosteroids may not be the first‐line treatment. Methods: The value of exhaled nitric oxide (ENO) in the diagnosis of EAI was prospectively investigated in a cohort of 116 patients with chronic cough of varying aetiology. An optimum cut‐off value was derived for differentiating between EAI and non‐EAI causes of chronic cough. As the diagnosis was gastro‐oesophageal reflux in 70 patients (60.3% of the total), the possible relationship between ENO and EAI in the presence or absence of reflux was subsequently investigated. Results: The optimum value of ENO for differentiating EAI (32% of patients) from non‐EAI causes of cough was 33 parts per billion (sensitivity 60.5%, specificity 84.6%). In the subgroup of patients with reflux, ENO was highly specific for the diagnosis of EAI (sensitivity 66%, specificity 100%). Conversely, in the patients without reflux, ENO did not discriminate between cough due to EAI or other causes (sensitivity 100%, specificity 28.9%). Conclusions: These results suggest that the presence or absence of reflux should be taken into consideration when interpreting ENO measurements in the diagnosis of chronic cough associated with EAI.     

Inhibition of allergen-induced airway remodelling by tiotropium and budesonide: a comparison.

Chronic inflammation in asthma and chronic obstructive pulmonary disease drives pathological structural remodelling of the airways. Using tiotropium bromide, acetylcholine was recently identified as playing a major regulatory role in airway smooth muscle remodelling in a guinea pig model of ongoing allergic asthma. The aim of the present study was to investigate other aspects of airway remodelling and to compare the effectiveness of tiotropium to the glucocorticosteroid budesonide. Ovalbumin-sensitised guinea pigs were challenged for 12 weeks with aerosolised ovalbumin. The ovalbumin induced airway smooth muscle thickening, hypercontractility of tracheal smooth muscle, increased pulmonary contractile protein (smooth-muscle myosin) abundance, mucous gland hypertrophy, an increase in mucin 5 subtypes A and C (MUC5AC)-positive goblet cell numbers and eosinophilia. It was reported previously that treatment with tiotropium inhibits airway smooth muscle thickening and contractile protein expression, and prevents tracheal hypercontractility. This study demonstrates that tiotropium also fully prevented allergen-induced mucous gland hypertrophy, and partially reduced the increase in MUC5AC-positive goblet cell numbers and eosinophil infiltration. Treatment with budesonide also prevented airway smooth muscle thickening, contractile protein expression, tracheal hypercontractility and mucous gland hypertrophy, and partially reduced MUC5AC-positive goblet cell numbers and eosinophilia. This study demonstrates that tiotropium and budesonide are similarly effective in inhibiting several aspects of airway remodelling, providing further evidence that the beneficial effects of tiotropium bromide might exceed those of bronchodilation.     

The relationship between large airway inflammation and airway metaplasia

To assess the role of acute inflammatory cells in large airways in the pathogenesis of metaplasia, we performed BAL (divided into aliquots) and mucosal biopsies on asbestos workers. They had evidence of asbestos-related lung injury. We found that acute inflammatory cells were significantly increased in the first aliquot. Ex-smokers had a greater percentage of PMN compared with nonsmokers and current smokers. The subjects were subgrouped with respect to biopsy-detected metaplasia. There was no difference between these groups for percentage or total number of PMN in the first aliquot. However, subjects with metaplasia had significant reduction in FEV1/FVC compared with those without. We conclude that there are significant differences in cells between the first and subsequent aliquots. Although inflammatory stimuli may be important in the pathogenesis of metaplasia, PMN present in the first aliquot could not be related to the severity of the metaplastic changes in these workers.