Neutrophil chemotactic activity of sputum from patients with COPD: role of interleukin 8 and leukotriene B4

Interfering with extracellular matrix degradation to blunt inflammation

Chemoattractant properties of matrix proteins, like collagen and elastin, for neutrophils and monocytes in vitro have long been recognized. This activity often resides in fragments of these proteins. These peptides may play a role in diseases of the lung matrix, such as chronic obstructive pulmonary disease. Recent advances include the elucidation of the structure of chemotactic collagen fragments and the demonstration that their activity may reside in a structural relatedness to CXC chemokines. Collagen and elastin fragments have been demonstrated to have a role in in vivo lung pathophysiology and have been quantified in patients with chronic lung diseases where they may activate autoimmune pathways. Elucidation of these pathways may provide novel biomarkers and therapeutic targets for chronic lung diseases.

Using guinea pigs in studies relevant to asthma and COPD

The guinea pig has been the most commonly used small animal species in preclinical studies related to asthma and COPD. The primary advantages of the guinea pig are the similar potencies and efficacies of agonists and antagonists in human and guinea pig airways and the many similarities in physiological processes, especially airway autonomic control and the response to allergen. The primary disadvantages to using guinea pigs are the lack of transgenic methods, limited numbers of guinea pig strains for comparative studies and a prominent axon reflex that is unlikely to be present in human airways. These attributes and various models developed in guinea pigs are discussed.

Targeting lung inflammation: novel therapies for the treatment of COPD

Chronic obstructive pulmonary disease (COPD) is a global health problem. As understanding of pathology of COPD has increased it has been established that COPD is associated with the progressive pulmonary inflammation and destruction of lung parenchyma (emphysema) that relate to disease severity. Therefore, it is anticipated that drugs that reduce pulmonary inflammation will provide effective, disease modifying therapy for COPD. Several specific therapies are directed against the influx of inflammatory cells into the airways and lung parenchyma that occurs in COPD; these include agents directed against cytokines and chemokines. Broad-range anti-inflammatory drugs are now in phase III development for COPD; they include inhibitors of phosphodiesterase 4 (PDE4). Other drugs that inhibit cell signaling include inhibitors of p38 mitogen-activated protein kinase (MAPK), nuclear factor-κB (NF-κB), and phosphoinositide-3-kinase (PI3K). There is also a search for inhibitors of proteinases and matrix metalloproteinases (MMPs) to prevent lung destruction and the development of emphysema. This review highlights studies on novel or potential anti-inflammatory agents that might be considered in the development of new future therapies for COPD.

Update on the pharmacologic therapy for chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease is a treatable disease characterized by progressive airflow limitation. Prevention of disease progression; improvement of symptoms, exercise tolerance, and health status; and decrease in exacerbations and mortality are the goals of management. Inhaled short-acting bronchodilators are recommended for symptoms in mild disease, whereas inhaled long-acting bronchodilators are recommended for maintenance therapy of daily symptoms. When symptoms are not controlled using one bronchodilator, combining bronchodilators may be more effective. Combining a long-acting beta-agonist with an inhaled corticosteroid is more effective than either agent alone. Several novel therapies are in different stages of development.

Bronchial epithelial spheroids: an alternative culture model to investigate epithelium inflammation-mediated COPD

Background

Chronic obstructive pulmonary disease (COPD) is characterized by abnormal lung inflammation that exceeds the protective response. Various culture models using epithelial cell lines or primary cells have been used to investigate the contribution of bronchial epithelium in the exaggerated inflammation of COPD. However, these models do not mimic in vivo situations for several reasons (e.g, transformed epithelial cells, protease-mediated dissociation of primary cells, etc.). To circumvent these concerns, we developed a new epithelial cell culture model.

Methods

Using non transformed non dissociated bronchial epithelium obtained by bronchial brushings from COPD and non-COPD smokers, we developed a 3-dimensional culture model, bronchial epithelial spheroids (BES). BES were analyzed by videomicroscopy, light microscopy, immunofluorescence, and transmission electron microscopy. We also compared the inflammatory responses of COPD and non-COPD BES. In our study, we chose to stimulate BES with lipopolycaccharide (LPS) and measured the release of the pro-inflammatory mediators interleukin-8 (IL-8) and leukotriene B4 (LTB4) and the anti-inflammatory mediator prostaglandin E2 (PGE2).

Results

BES obtained from both COPD and non-COPD patients were characterized by a polarized bronchial epithelium with tight junctions and ciliary beating, composed of basal cells, secretory cells and ciliated cells. The ciliary beat frequency of ciliated cells was not significantly different between the two groups. Of interest, BES retained their characteristic features in culture up to 8 days. BES released the inflammatory mediators IL-8, PGE2 and LTB4 constitutively and following exposure to LPS. Interestingly, LPS induced a higher release of IL-8, but not PGE2 and LTB4 in COPD BES (p < 0.001) which correlated with lung function changes.

Conclusion

This study provides for the first time a compelling evidence that the BES model provides an unaltered bronchial surface epithelium. More importantly, BES represent an attractive culture model to investigate the mechanisms of injuring agents that mediate epithelial cell inflammation and its contribution to COPD pathogenesis.

Tiotropium suppresses acetylcholine-induced release of chemotactic mediators in vitro

The driving force in the progression of COPD is the development of exacerbations which are mostly the result of excessive inflammation. Bronchodilatators play an important role in the treatment of COPD. The reported reduction in exacerbation rates in COPD is due to the inhibition of vagal-mediated bronchoconstriction and mucus secretion. However, recent studies have highlighted the existence of muscarinic receptors on inflammatory cells and we have explored the possibility that tiotropium bromide might also inhibit neutrophil migration. We analysed the influence of tiotropium on the release of neutrophil chemotactic activity in response to acetylcholine (ACh) and the expression of muscarinic receptors on human alveolar macrophages (AM), A549 cells, MonoMac6 cells, and human lung fibroblasts. We found significant levels of all muscarinic receptor subtypes on all analysed cells except the fibroblasts. Fibroblasts expressed predominantly M2, receptors and did not release chemotactic activity. AM, A549 cells, and MonoMac6 cells released chemotactic active mediators after incubation with ACh. The secretion could be suppressed by more than 70% after coincubation with tiotropium. Tiotropium alone did not influence the granulocyte migration. Most of the chemotactic activity could be attributed to leukotriene B4 (LTB4). The release of interleukin-8 (IL-8) and monocyte chemotactic protein-1 (MCP-1) was not induced by ACh. From this, we suggest that the suppression of the Ach-mediated release of chemotactic substances like LTB4 modulates the inflammatory reaction. This may contribute to the decreased rate of exacerbations in COPD, which was observed in clinical trials.

Aspects on pathophysiological mechanisms in COPD

Chronic obstructive pulmonary disease (COPD) is a condition which is characterized by irreversible airway obstruction due to narrowing of small airways, bronchiolitis, and destruction of the lung parenchyma, emphysema. It is the fourth most common cause of mortality in the world and is expected to be the third most common cause of death by 2020. The main cause of COPD is smoking but other exposures may be of importance. Exposure leads to airway inflammation in which a variety of cells are involved. Besides neutrophil granulocytes, macrophages and lymphocytes, airway epithelial cells are also of particular importance in the inflammatory process and in the development of emphysema. Cell trafficking orchestrated by chemokines and other chamoattractants, the proteinase-antiproteinase system, oxidative stress and airway remodelling are central processes associated with the development of COPD. Recently systemic effects of COPD have attracted attention and the importance of systemic inflammation has been recognized. This seems to have direct therapeutic implications as treatment with inhaled glucocorticosteroids has been shown to influence mortality. The increasing body of knowledge regarding the inflammatory mechanism in COPD will most likely have implications for future therapy and new drugs, specifically aimed at interaction with the inflammatory processes, are currently being developed.

Chemokines and their receptors in respiratory disease: a therapeutic target for respiratory syncytial virus infection

Cell recruitment is a multistep process orchestrated by chemokines and their receptors. The chemokine/receptor system is central to many inflammatory diseases, making it a key target for therapeutic intervention. Despite complexity and redundancy within the system, effective antagonists are in development and undergoing clinical trials, for example, maraviroc, for use in HIV treatment. Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infection in infants, with global annual infection estimated at 64 million people. Current treatment is purely supportive, with no effective vaccine available. RSV pathology is partly due to excessive airway inflammation. Evidence is growing for a key role for chemokine receptors. Receptor blockade may therefore provide a feasible therapeutic option to inhibit RSV-induced inflammation and thereby reduce disease severity.

Granulocyte Chemotactic Activity in Exhaled Breath Condensate of Healthy Subjects and Patients With COPD

BACKGROUND

Several chemoattractants have been measured in exhaled breath condensate (EBC) from patients with COPD. The aim of this study was to compare the eosinophil and neutrophil chemotactic activity contained in EBC from healthy subjects and patients with COPD.

METHODS

EBC collected using a commercially available condenser (EcoScreen; Erich Jaeger Viasys; Hoechberg, Germany) was compared in 45 COPD patients and 65 healthy subjects. EBC chemotactic activity for eosinophils and neutrophils was assessed using microchambers (Boyden; Neuro Probe; Cabin John, MD). Chemotactic index (CI) was used to evaluate cell migration.

RESULTS

EBC from patients with COPD (CI, 2.21 +/- 0.16 [mean +/- SEM]) and healthy subjects (CI, 1.67 +/- 0.11) displayed significant neutrophil chemotactic activity (p < 0.0001 for both), which was however higher in patients with COPD (p < 0.001). Healthy smokers had a significantly raised CI for neutrophils by comparison with healthy nonsmokers (p < 0.01) and ex-smokers (p < 0.05). Likewise, current COPD smokers tended to have greater neutrophil CI than COPD who stopped smoking (p = 0.08). COPD ex-smokers had raised chemotactic activity by comparison with healthy ex-smokers (p < 0.05). Anti-interleukin-8 (10(-6) g/mL) antibodies reduced neutrophil chemotactic activity by 35.2% (p < 0.05). EBC also contained significant eosinophil chemotactic activity in healthy subjects (CI, 1.68 +/- 0.09; p < 0.0001) and patients with COPD (CI, 1.23 +/- 0.07; p < 0.01), with a significantly lower CI in patients with COPD as compared to healthy subjects (p < 0.001). Smoking did not influence eosinophil chemotactic activity in healthy subjects or patients with COPD.

CONCLUSIONS

Current smoking favors neutrophil chemotactic activity. As compared to healthy subjects, EBC from patients with COPD displays a skewed chemotactic activity toward neutrophils vs eosinophils.

Pharmacological characterization of Sch527123, a potent allosteric CXCR1/CXCR2 antagonist

In neutrophils, growth-related protein-alpha (CXCL1) and interleukin-8 (CXCL8), are potent chemoattractants (Cytokine 14:27-36, 2001; Biochemistry 42:2874-2886, 2003) and can stimulate myeloperoxidase release via activation of the G protein-coupled receptors CXCR1 and CXCR2. The role of CXCR1 and CXCR2 in the pathogenesis of inflammatory responses has encouraged the development of small molecule antagonists for these receptors. The data presented herein describe the pharmacology of 2-hydroxy-N,N-dimethyl-3-{2-[[(R)-1-(5-methyl-furan-2-yl)-propyl]amino]-3,4-dioxo-cyclobut-1-enylamino}-benzamide (Sch527123), a novel antagonist of both CXCR1 and CXCR2. Sch527123 inhibited chemokine binding to (and activation of) these receptors in an insurmountable manner and, as such, is categorized as an allosteric antagonist. Sch527123 inhibited neutrophil chemotaxis and myeloperoxidase release in response to CXCL1 and CXCL8 but had no effect on the response of these cells to C5a or formyl-methionyl-leucyl-phenylalanine. The pharmacological specificity of Sch527123 was confirmed by testing in a diversity profile against a panel of enzymes, channels, and receptors. To measure compound affinity, we characterized [(3)H]Sch527123 in both equilibrium and nonequilibrium binding analyses. Sch527123 binding to CXCR1 and CXCR2 was both saturable and reversible. Although Sch527123 bound to CXCR1 with good affinity (K(d) = 3.9 +/- 0.3 nM), the compound is CXCR2-selective (K(d) = 0.049 +/- 0.004 nM). Taken together, our data show that Sch527123 represents a novel, potent, and specific CXCR2 antagonist with potential therapeutic utility in a variety of inflammatory conditions.

New molecular targets for the treatment of neutrophilic diseases

Increased neutrophils are a feature of airway inflammation in patients with chronic obstructive pulmonary disease and in some patients with asthma, particularly patients with more severe disease, during exacerbations and with cigarette smoking. Because neutrophilic inflammation may be detrimental, there are several new approaches to inhibiting neutrophilic inflammation. Neutrophilic inflammation is resistant or poorly responsive to corticosteroids, so different anti-inflammatory approaches are needed. Blocking neutrophil chemotactic factors such as leukotriene B(4) and IL-8 and related cysteine-X-cysteine chemokines by blocking receptor for leukotriene B(4) 1 and receptor for cysteine-X-cysteine chemokines 2 receptors is an approach that is currently being investigated. Other approaches include blocking adhesion molecules such as E-selectin. Inhibiting phosphodiesterase-4, nuclear factor-kappaB, or p38 mitogen-activated protein kinase is another approach that inhibits the production of cysteine-X-cysteine chemokines. Antioxidants, long-acting beta(2)-agonists, and activators of histone deacetylase may also be effective.

Long-term treatment with theophylline reduces neutrophils, interleukin-8 and tumor necrosis factor-α in the sputum of patients with chronic obstructive pulmonary disease

BACKGROUND

The non-selective phosphodiesterase inhibitor theophylline has bronchodilator/anti-inflammatory properties and is widely used in the treatment of airways diseases. We determined the effect of long-term theophylline treatment on airway inflammation in patients with chronic obstructive pulmonary disease (COPD).

POPULATIONS AND METHODS

Seventeen stable COPD patients were enrolled in the 12-month study. Theophylline was administered at 400mg/day. We studied changes in symptoms, spirometry, sputum volume, and sputum inflammatory cytokines levels. We also examined the effects of theophylline on the release of inflammatory cytokines in vitro by measuring interleukin (IL)-8 and tumor necrosis factor (TNF)-alpha levels from lipopolysaccharide (LPS)-stimulated neutrophils and THP-1 cells.

RESULTS

Forced vital capacity was increased and sputum IL-8 levels decreased after 4 weeks of theophylline treatment. After 6 months of theophylline treatment, forced expiratory volume in 1s was increased, and neutrophils counts and TNF-alpha levels in sputum were reduced. Levels of IL-8 and TNF-alpha released by LPS-stimulated THP-1 cells were reduced by treatment with theophylline at 10microg/ml. In contrast, IL-8 levels released by LPS-stimulated neutrophils were reduced by treatment with theophylline at 100microg/ml.

CONCLUSION

Our clinical study of small population showed that long-term treatment with theophylline seems to reduce airway inflammation in stable COPD patients.

Pharmacotherapy of diseases mediated by 5-lipoxygenase pathway eicosanoids

Inflammatory eicosanoids generated by the 5-lipoxygenase (5-LO) pathway of arachidonic acid metabolism are now known to have at least 6 receptors: OXE, which recognizes 5-HETE and 5-oxo-ETE; a putative receptor recognizing a potent 5-oxo-ETE metabolite, FOG(7); the LTB(4) receptors, BLT1 and BLT2; the cysteinyl leukotriene receptors, CysLT(1) and CysLT(2), which recognize leukotrienes LTC(4), LTD(4), LTE(4) and LTF(4). The 5-LO pathway is activated in many diseases and invokes inflammatory responses not affected by glucocorticoids, but therapy with selective BLT1 or CysLT(1) antagonists in asthma has met with variable success. Studies show that 5-LO pathway eicosanoids are not primary mediators in all cases of asthma, but may be especially important in severe persistent asthma, aspirin- and exercise-induced asthma, allergic rhinitis, COPD, idiopathic pulmonary fibrosis, atherosclerosis, atopic dermatitis, acne and ischemia-related organ injury. These disorders appear to involve multiple 5-LO pathway eicosanoids and receptor subtypes, suggesting that inhibition of the pathway at the level of 5-LO may be necessary for maximal efficacy.

Systemic inflammation in COPD: is genetic susceptibility a key factor?

COPD is a multicomponent disease characterized by abnormal inflammatory response of the lungs to noxious particles that is accompanied by systemic effects like weight loss, muscle wasting, reduced functional capacity and impaired health status. A persistent low-grade systemic inflammatory response reflected by enhanced levels of acute phase proteins like C-reactive protein (CRP) and pro-inflammatory cytokines such as tumor necrosis factor (TNF)-alpha, is present in part of the COPD population. The production of inflammatory proteins is partly genetically determined. Several studies have shown that polymorphisms within genes coding for these inflammatory mediators may modulate systemic inflammatory responses. Among all of these genes, the TNF family (TNF-alpha, lymphotoxin (LT)-alph and their receptors TNF-R55 and TNF-R75), interleukin (IL)-6 and CRP gene polymorphisms are the most prominent candidates. However, large carefully designed studies in well-characterized COPD cohorts are required to unravel the exact role of genetic background in the systemic component of this disease.

Impaired neutrophil chemotaxis in chronic obstructive pulmonary disease

RATIONALE

Neutrophilic airway inflammation is considered to be a major factor in the pathogenesis of chronic obstructive pulmonary disease (COPD), with sputum and bronchoalveolar lavage neutrophil counts broadly correlating with disease severity. The mechanisms responsible for neutrophil accumulation are poorly understood, but they could involve increased influx and/or survival of these cells.

OBJECTIVES

To investigate whether neutrophil chemotactic responsiveness and/or chemotactic activity in airway secretions are increased in subjects with COPD.

METHODS

Chemotaxis experiments were performed using induced sputum supernatants from subjects with and without COPD as a source of chemotactic activity, and neutrophils from healthy donors as responder cells. In addition, chemotactic responses to N-formyl-Met-Leu-Phe (fMLP) and interleukin-8 (IL-8/CXCL8) were studied using neutrophils from healthy subjects and subjects with COPD.

MEASUREMENTS AND MAIN RESULTS

As reported in the literature, sputum neutrophil counts were significantly increased in subjects with COPD compared with healthy subjects. However, this was associated with reduced chemotactic activity in sputum in COPD, as judged by reduced chemotaxis to the fluid phase of sputum from subjects with COPD compared with healthy subjects. Furthermore, whereas neutrophils from subjects with stage I COPD had normal responses to fMLP and IL-8, subjects with more severe stage II-IV COPD showed reduced levels of spontaneous migration and chemotaxis to fMLP and IL-8.

CONCLUSIONS

Neither increased chemotactic activity in the airways nor increased chemotactic responsiveness of neutrophils explains the increased number of these cells in subjects with stable COPD. The implications of the observed reduction in neutrophil chemotactic activity remain to be established.

The genetics of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease caused by the interaction of genetic susceptibility and environmental influences. There is increasing evidence that genes link to disease pathogenesis and heterogeneity by causing variation in protease anti-protease systems, defence against oxidative stress and inflammation. The main methods of genomic research for complex disease traits are described, together with the genes implicated in COPD thus far, their roles in disease causation and the future for this area of investigation.

Chemokine receptors as therapeutic targets in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is an increasing global health problem for which there are no effective disease-modifying therapies. COPD involves chronic inflammation of small airways and lung parenchyma, with the recruitment of inflammatory cells. This inflammatory-cell trafficking is orchestrated by multiple chemokines, so the blockade of chemokine receptors with selective antagonists might be an effective anti-inflammatory strategy in this disease. Several studies support the implication of several chemokines and their receptors in COPD, including chemokine receptors CXCR2 and CXCR3, with small-molecule receptor antagonists that are in development being potential anti-inflammatory therapies. Such a pharmacological strategy would provide a mechanism with which to inhibit leukocyte recruitment and, hence, reduce the inflammatory profile in COPD, which is currently unaffected by pharmacotherapy.

Effects of diesel exhaust particles on human neutrophil activation

Diesel exhaust particles (DEP) are associated with respiratory disease and exposure to diesel exhaust induces an inflammatory response associated with marked leukocytic infiltration in the lung. This study examined whether neutrophils are activated by the active component of DEP (methanol extract of DEP [me-DEP]). The authors demonstrated that neutrophils exposed to me-DEP had increased levels of the f-actin content, the surface expression of adhesion molecules, and the release of interleukin (IL-8) and leukotriene B4 (LTB4), superoxide, and matrix metalloproteinase (MMP-9). Thus, the author conclude that DEP exposure activates neutrophils and that these activated neutrophils could contribute to the adverse respiratory health effects associated with DEP and to the pathogenesis of chronic inflammatory lung diseases.

Handle with care: targeting neutrophils in chronic obstructive pulmonary disease and severe asthma?

Neutrophils play an important role in the pathogenesis of airway inflammation in both chronic obstructive pulmonary disease (COPD) and severe asthma. Currently available drugs have only limited effects on neutrophilic airway inflammation, particularily in COPD. Therefore, great efforts are undertaken to address neutrophilic inflammation in chronic respiratory disorders, in particular COPD. This review summarizes the rationale for anti-neutrophilic treatment in COPD and asthma and gives a critical overview of current developments in drug therapy. Moreover, unanswered questions and limitations of clinical trial design and choice of outcome parameters for proof-of-concept studies with novel anti-neutrophilic drugs are discussed as well as potential safety issues.

Up-regulated membrane and nuclear leukotriene B4 receptors in COPD

STUDY OBJECTIVES

We investigated the role of two leukotriene B4 (LTB4) receptors, BLT1 and peroxisome proliferator-activated receptor (PPAR)-alpha, in conferring the susceptibility to develop COPD in smokers. Proinflammatory LTB4 activities are mediated by BLT1, while the inactivation of LTB4 is promoted by PPARalpha.

PATIENTS AND METHODS

BLT1 and PPARalpha proteins were quantified by immunohistochemistry in specimens obtained during lung surgery from 19 smokers with or without COPD and from 7 nonsmoking subjects.

RESULTS

We have shown that the percentages of PPARalpha-positive alveolar macrophages and PPARalpha-positive cells in the alveolar wall were increased in COPD patients compared with control subjects. Moreover, the patients with COPD exhibited a significant increase of BLT1-positive alveolar macrophages compared with nonsmokers and an increased number of BLT1-positive cells in the alveolar walls compared with non-COPD smokers. In contrast, BLT1 and PPARalpha immunoreactivity did not differ significantly between nonsmokers and non-COPD smokers. Most of BLT1-positive cells in the alveolar walls were neutrophils and CD8 cells. While the number of neutrophils infiltrating the lung parenchyma was similar among the three groups, the number of CD8 T cells was increased in COPD patients, but there was no evidence that BLT1 was up-regulated specifically on these cells in COPD patients.

CONCLUSION

The results demonstrated that BLT1 and PPARalpha are detectable in alveolar macrophages and CD8 T cells in human lung tissue, and suggest that the dual LTB4 receptor system is up-regulated in the peripheral lungs of smokers who are susceptible to the development of COPD. This system might represent a novel target for therapeutic intervention in COPD patients.

Role of 5-Lipoxygenase in IL-13-Induced Pulmonary Inflammation and Remodeling

Exaggerated levels of IL-13 and leukotriene (LT) pathway activation frequently coexist at sites of Th2 inflammation and in tissue fibrotic responses. However, the relationship(s) between the IL-13 and LTs in these responses have not been defined. We hypothesized that the 5-lipoxygenase (5-LO) pathway of LT metabolism plays an important role in the pathogenesis of IL-13-induced chronic inflammation and remodeling. To test this hypothesis, we evaluated the effects of IL-13 on components of the 5-LO metabolic and activation pathways. We also compared the effects of transgenic IL-13 in C57BL/6 mice with wild-type and null 5-LO genetic loci. These studies demonstrate that IL-13 increases the levels of mRNA encoding cytosolic phospholipase A(2), LTA(4) hydrolase, and 5-LO-activating protein without altering the expression of 5-LO, LTC(4) synthase, LTB(4) receptors 1 and 2, and cysteinyl-LT receptors 1 and 2. They also demonstrate that this activation is associated with the enhanced accumulation of LTB(4) but not of cysteinyl-LTs. Furthermore, they demonstrate that this stimulation plays a critical role in the pathogenesis of IL-13-induced inflammation, tissue fibrosis, and respiratory failure-induced death while inhibiting alveolar remodeling. Lastly, mechanistic insights are provided by demonstrating that IL-13-induced 5-LO activation is required for optimal stimulation and activation of TGF-beta(1) and the inhibition of matrix metalloproteinase-12. When viewed in combination, these studies demonstrate that 5-LO plays an important role in IL-13-induced inflammation and remodeling.

CysLT1 receptor engagement induces activator protein-1- and NF-kappaB-dependent IL-8 expression

Because cysteinyl-leukotrienes (cysLTs) are major protagonists in the pathophysiology of human asthma, and because neutrophils are involved in the more severe form of asthma, we studied the potential for leukotriene (LT) D(4) to induce synthesis of the chemokine IL-8 through activation of the CysLT1 receptor. We found LTD(4) to induce IL-8 gene expression in monocytic THP-1 cells and human dendritic cells with complete abrogation by selective CysLT1 antagonists. Human embryonic kidney-293 cells stably transfected with CysLT1 were used to better study the transcriptional regulation of the IL-8 promoter. Stimulation of the cells with graded concentrations of LTD(4) resulted in a time- and concentration-dependent induction of IL-8 transcription and protein synthesis. Use of IL-8 promoter mutants with substitutions in their NF-kappaB, activator protein (AP)-1, and NF-IL-6 binding elements revealed a requirement for NF-kappaB and AP-1, but not NF-IL-6, in LTD(4)-induced activation of the IL-8 promoter. Overexpression of dominant-negative IkappaBalpha inhibited the IL-8 transactivation induced by LTD(4). NF-kappaB DNA binding activity was induced by LTD(4), as determined by electrophoretic mobility shift assays, and could be supershifted by antibodies against p50 and p65. Supershift assays after LTD(4) stimulation also indicated the formation of a c-Jun/c-Fos complex. Moreover, our results demonstrate that LTD(4) upregulates the expression of c-fos and c-jun at the mRNA level. Our data show for the first time that LTD(4), via the CysLT1 receptor, can transcriptionally activate IL-8 production, with involvement of the transcription factors p50, p65, Fos, and Jun. These findings provide mechanistic and potentially therapeutic elements for modulation of the inflammatory component of asthma.

Structural changes in airway diseases: characteristics, mechanisms, consequences, and pharmacologic modulation

In airway diseases such as asthma and COPD, specific structural changes may be observed, very likely secondary to an underlying inflammatory process. Although it is still controversial, airway remodeling may contribute to the development of these diseases and to their clinical expression and outcome. Airway remodeling has been described in asthma in various degrees of severity, and correlations have been found between such features as increase in subepithelial collagen or proteoglycan deposits and airway responsiveness. Although the clinical significance of airway remodeling remains a matter of debate, it has been suggested as a potential target for treatments aimed at reducing asthma severity, improving its control, and possibly preventing its development. To date, drugs used to treat airway diseases have a little influence on airway structural changes. More research should be done to identify key changes, valuable treatments, and proper interventional timing to counteract these changes. The potential of novel therapeutic agents to reverse or prevent airway remodeling is an exciting avenue and warrants further evaluation.

Should patients with acute exacerbation of chronic bronchitis be treated with antibiotics? Advantages of the use of fluoroquinolones

The pathological changes in chronic bronchitis (CB) produce airflow obstruction, reduce the effectiveness of the mucocilliary drainage system and lead to bacterial colonisation of bronchial secretion. The presence of bacteria induces an inflammatory response mediated by leukocytes. There is a direct relationship between the degree of impairment of the mucocilliary drainage system, the density of bacteria in mucus and the number of leukocytes in the sputum. Purulent sputum is a good marker of a high bacterial load. Eventually, if the number of leukocytes is high, their normal activity could decrease the effectiveness of the drainage system, increase the bronchial obstruction and probably damage the lung parenchyma. Whenever the density of bacteria in the bronchial lumen is >or=10(6) CFU/mL, there is a high probability that the degree of inflammatory response will lead to a vicious cycle which in turn tends to sustain the process. This situation can arise during the clinical course of any acute exacerbation of CB, independently of its aetiology, provided the episode is sufficiently severe and/or prolonged. Fluoroquinolones of the third and fourth generation are bactericidal against most microorganisms usually related to acute exacerbations of CB. Their diffusion to bronchial mucus is adequate. When used in short (5-day) treatment they reduce the bacterial load in a higher proportion than is achieved by beta-lactam or macrolide antibiotics given orally. Although the clinical cure rate is similar to that obtained with other antibiotics, the time between exacerbations could be increased.

Expression of 5-lipoxygenase in specialized epithelial cells of nasopharyngeal-associated lymphoid tissue

Leukotrienes are lipid mediators that are produced primarily by certain types of leukocytes. The synthesis of the leukotriene LTB(4) is initiated by the enzyme 5-lipoxygenase and completed by LTA(4) hydrolase. Epithelial cells constitutively express LTA(4) hydrolase but normally lack 5-lipoxygenase. In this study, we report that the stratified squamous epithelial cells from inflamed or hyperplastic tissues of palatine and pharyngeal tonsils (nasopharyngeal-associated lymphoid tissue) express 5-lipoxygenase protein. The localization of 5-lipoxygenase was indicated by immunohistochemical staining and presence confirmed by immunoblot. Positive staining for 5-lipoxygenase in infiltrating leukocytes in inflamed tissues served as internal positive controls for immunohistochemical staining. Staining for 5-lipoxygenase in appendix tissue was negative for epithelial cells while positive for polymorphonuclear leukocytes, indicating that 5-lipoxygenase expression is not a general feature of epithelial cells in mucosa-associated lymphoid tissue. In tonsils, 5-lipoxygenase staining was pronounced in broad regions but reduced or absent in others, suggesting regional regulation of expression. Epithelial cells of tonsils were also positive for 5-lipoxygenase activating protein and leukotriene A(4) hydrolase, indicating a capacity to produce LTB(4). Taken together, these results suggest that the specialized epithelial cells of the mucosa-associated lymphoid tissue of human tonsils can synthesize LTB(4). This lipid mediator may serve to modulate the function of cells within the lymphoid tissue as well as promote an inflammatory response.

Gene therapy for chronic obstructive pulmonary disease: twilight or triumph?

Chronic obstructive pulmonary disease (COPD) is a clinical syndrome presenting as progressive airflow limitation that is poorly reversible as a result of bronchitis and emphysema. The prevalence of COPD is alarming and even more so its current and projected impact on morbidity and mortality. To date, there are no effective treatments for emphysema, nor are there efficient clinical management strategies. Existing and prospective therapies, although promising, have yet to demonstrate their efficacy to slow, halt or reverse the disease. Novel approaches using gene therapy and stem cell technologies may offer new opportunities. However, this will remain almost entirely dependent on a more thorough understanding of the pathogenesis of COPD. This review is not aimed at highlighting the vast effort of studying COPD, but rather describing the state of the field in an abstract fashion to expose the focus of research efforts to date, which has primarily been limited to predisposing factors and inflammation. We would like to draw attention to other elements of the disease, such as the alveolar remodelling that characterises emphysema. Although the main cause may prove to be elusive, carefully designed clinical treatment and management may deliver the required therapeutic outcome.

A novel peptide CXCR ligand derived from extracellular matrix degradation during airway inflammation

We describe the tripeptide neutrophil chemoattractant N-acetyl Pro-Gly-Pro (PGP), derived from the breakdown of extracellular matrix (ECM), which shares sequence and structural homology with an important domain on alpha chemokines. PGP caused chemotaxis and production of superoxide through CXC receptors, and administration of peptide caused recruitment of neutrophils (PMNs) into lungs of control, but not CXCR2-deficient mice. PGP was generated in mouse lung after exposure to lipopolysaccharide, and in vivo and in vitro blockade of PGP with monoclonal antibody suppressed PMN responses as much as chemokine-specific monoclonal antibody. Extended PGP treatment caused alveolar enlargement and right ventricular hypertrophy in mice. PGP was detectable in substantial concentrations in a majority of bronchoalveolar lavage samples from individuals with chronic obstructive pulmonary disease, but not control individuals. Thus, PGP's activity links degradation of ECM with neutrophil recruitment in airway inflammation, and PGP may be a biomarker and therapeutic target for neutrophilic inflammatory diseases.

Agents against cytokine synthesis or receptors

Various cytokines play a critical role in pathophysiology of chronic inflammatory lung diseases including asthma and chronic obstructive pulmonary disease (COPD). The increasing evidence of the involvement of these cytokines in the development of airway inflammation raises the possibility that these cytokines may become the novel promising therapeutic targets. Studies concerning the inhibition of interleukin (IL)-4 have been discontinued despite promising early results in asthma. Although blocking antibody against IL-5 markedly reduces the infiltration of eosinophils in peripheral blood and airway, it does not seem to be effective in symptomatic asthma, while blocking IL-13 might be more effective. On the contrary, anti-inflammatory cytokines themselves such as IL-10, IL-12, IL-18, IL-23 and interferon-gamma may have a therapeutic potential. Inhibition of TNF-alpha may also be useful in severe asthma or COPD. Many chemokines are also involved in the inflammatory response of asthma and COPD through the recruitment of inflammatory cells. Several small molecule inhibitors of chemokine receptors are now in development for the treatment of asthma and COPD. Antibodies that block IL-8 reduce neutrophilic inflammation. Chemokine CC3 receptor antagonists, which block eosinophil chemotaxis, are now in clinical development for asthma therapy. As many cytokines are involved in the pathophysiology of inflammatory lung diseases, inhibitory agents of the synthesis of multiple cytokines may be more useful tools. Several such agents are now in clinical development.

Biological targets for therapeutic interventions in COPD: clinical potential

COPD is a widespread inflammatory respiratory disorder characterized by a progressive, poorly reversible airflow limitation. Currently available therapies are mostly based on those used to treat asthma. However, such compounds are not able to effectively reduce the gradual functional deterioration, as well as the ongoing airway and lung inflammation occurring in COPD patients. Therefore, there is an urgent need to improve the efficacy of the existing drug classes and to develop new treatments, targeting the main cellular and molecular mechanisms underlying disease pathogenesis. These therapeutic strategies will be highlighted in the present review.

Treatments for COPD

The multicomponent nature of chronic obstructive pulmonary disease (COPD) has provided a challenging environment in which to develop successful treatments. A combination of pharmacological and non-pharmacological approaches is used to combat this problem, and an overview of these approaches and their possible future direction is given. Bronchodilators are the mainstay of COPD treatment and can be combined with inhaled corticosteroids for greater efficacy and fewer side effects. A new generation of pharmacotherapeutic agents, most notably phosphodiesterase-4 inhibitors, which are already in the advanced stages of clinical development, and leukotriene B4 inhibitors (in early clinical development), may shape future treatment as further insight is gained into the pathological mechanisms underlying COPD. Non-pharmacologic treatments for COPD include long-term oxygen therapy (LTOT), nasal positive pressure ventilation (nPPV), pulmonary rehabilitation and lung-volume-reduction surgery (LVRS). Apart from smoking cessation, LTOT is the only treatment to date which has been shown to modify survival rates in severe cases; thus its role in COPD is well defined. The roles of nPPV and LVRS are less clear, though recent progress is reported here. In the future, it will be important to establish the precise value of the different treatments available for COPD--evaluating both clinical and physiological endpoints and using the data to more accurately define candidate patients accordingly. The challenge will be to develop this base of knowledge in order to shape future research and allow clinicians to deliver tailored COPD management programmes for the growing number of patients afflicted with this disease.

Neutrophilic inflammation and IL-8 levels in induced sputum of alpha-1-antitrypsin PiMZ subjects

BACKGROUND

Severe alpha-1-antitrypsin deficiency (AATD), due to homozygosity for the protease inhibitor (Pi) Z allele, is a genetic risk factor for chronic obstructive pulmonary disease (COPD). In a previous study the sputum of severe AATD subjects with airflow obstruction showed a pattern of cellular inflammation similar to COPD patients. It is uncertain whether heterozygotes for the Z allele or intermediate deficiency (PiMZ) have an increased risk of developing COPD.

METHODS

Sputum cell counts and the supernatant level of the neutrophil chemoattractant interleukin (IL)-8 were investigated by sputum induction in 10 non-smoker asymptomatic PiMZ subjects with normal pulmonary function, 10 patients with stable COPD, and 10 age matched normal subjects. Data are expressed as mean (SD).

RESULTS

The mean (SD) number of neutrophils was significantly higher (p<0.01) in the sputum of PiMZ subjects (84.5 (22.2) x10(4)/ml) and patients with COPD (126.9 (18.8) x10(4)/ml) than in matched normal subjects (55.0 (8.7) x10(4)/ml). IL-8 levels were increased in PiMZ subjects (828.5 (490.6) ng/ml; median 1003.0 ng/ml; range 1260-100 ng/ml) and in COPD patients (882.5 (524.3) ng/ml; median 934.9 ng/ml; range 1506-258 mg/ml) compared with normal subjects (3.5 (0.5) ng/ml; median 3.5 ng/ml; range 4.5-2.5 ng/ml). There was a significant positive correlation between IL-8 supernatant concentration and neutrophil count in PiMZ subjects (p = 0.036; r = 0.66). An inverse correlation was observed between the percentage of neutrophils and forced expiratory volume in 1 second (% predicted) in patients with COPD (p = 0.04; r = -0.43).

CONCLUSIONS

These findings indicate that PiMZ subjects without airflow obstruction may have an IL-8 related neutrophilic inflammation in the airways, similar to stable COPD patients, suggesting an increased risk of developing pulmonary changes.

Exhaled breath condensate cytokine patterns in chronic obstructive pulmonary disease

Differences in cytokine patterns in stable chronic obstructive pulmonary disease (COPD), exacerbated COPD, smokers without apparent COPD, and healthy volunteers should be of interest for pathophysiological and therapeutic reasons. Methods including lavage, biopsy and sputum have been employed to investigate cytokines in the lung. For asystematic comparison, exhaled breath condensate (EBC) appears to be well suited. We investigated healthy volunteers, smokers without apparent COPD, stable and exacerbated COPD patients (+/- inhalative steroids) and finally those whose exacerbation made mechanical ventilation inevitable, for a more complete picture of inflammatory cytokines in COPD. We chose EBC because it is non-invasive and can be used repeatedly in spontaneous breathing individuals and during mechanical ventilation. EBC cytokines (IL-1 beta, IL-6, IL-8, IL-10, IL-12 p 70, TNF-alpha) were assayed from a single sample using a multiplex array test kit. We observed a significant increase of all cytokines in acute exacerbation compared to stable COPD, smokers, and volunteers. Stable COPD and volunteers exhibited only small differences in cytokine pattern with respect to IL-1 beta and IL-12 (P<0.01). Smokers had increased levels of all investigated cytokines (P<0.01) compared to non-smokers and, with the exception of IL-1 beta, to stable COPD. Inhaled steroids resulted in reduced levels of IL-1 beta, IL-6, IL-8, IL-10, and IL-12 (all: P<0.01) in stable COPD (all: ex-smokers) with dose dependency for IL-8, IL-1 beta and IL-12. EBC analysis successfully characterized important differences in stable COPD compared to exacerbation or smoking and non-smoking healthy individuals.

Acute respiratory infection with mouse adenovirus type 1

Studies of the pathogenesis of adenovirus respiratory disease are limited by the strict species-specificity of the adenoviruses. Following intranasal inoculation of adult C57BL/6 mice with mouse adenovirus type 1 (MAV-1), we detected MAV-1 early region 3 (E3) and hexon gene expression in the lungs at 7 days post-infection (dpi). We detected MAV-1 E3 protein in the respiratory epithelium at 7 dpi. We did not detect viral mRNA or protein at 14 dpi, but MAV-1 DNA was detected by PCR at 21 dpi. Chemokine transcript levels increased between 7 and 14 dpi in the lungs of infected mice. MAV-1 infection induced a patchy cellular infiltrate in lungs at 7 and 14 dpi. This is the first report demonstrating the presence of MAV-1 in the respiratory epithelium of infected mice and describing chemokine responses in the lung induced by MAV-1 respiratory infection. MAV-1 infection of mice has the potential to serve as a model for inflammatory changes seen in human adenovirus respiratory disease.

Mediators of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major and increasing global health problem that is now a leading cause of death. COPD is associated with a chronic inflammatory response, predominantly in small airways and lung parenchyma, which is characterized by increased numbers of macrophages, neutrophils, and T lymphocytes. The inflammatory mediators involved in COPD have not been clearly defined, in contrast to asthma, but it is now apparent that many lipid mediators, inflammatory peptides, reactive oxygen and nitrogen species, chemokines, cytokines, and growth factors are involved in orchestrating the complex inflammatory process that results in small airway fibrosis and alveolar destruction. Many proteases are also involved in the inflammatory process and are responsible for the destruction of elastin fibers in the lung parenchyma, which is the hallmark of emphysema. The identification of inflammatory mediators and understanding their interactions is important for the development of anti-inflammatory treatments for this important disease.

Interleukin-17-Induced Interleukin-8 Release in Human Airway Smooth Muscle Cells: Role for Mitogen-Activated Kinases and Nuclear Factor-κB

BACKGROUND

It has recently become clear that interleukin (IL)-8 plays a role in chronic neutrophilic inflammatory disorders, such as chronic rejection after lung transplantation. We have shown that IL-17--stimulated human airway smooth muscle cells (HASMC) are able to produce IL-8. The aim of this study was to determine whether p38 mitogen-activated protein kinase (MAPK), c-Jun amino-terminal kinase (JNK), p42/p44 extracellular signal-related kinase (ERK) and nuclear factor-kappaB (NF-kappaB) are involved in IL-17--induced IL-8 production in HASMC in vitro.

METHODS

We used human airway smooth muscle cells in culture. Western blotting was done to obtain data regarding activation of MAPK. Furthermore, we used specific inhibitors of MAPK to investigate their involvement in IL-17--induced IL-8 release, which was measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Western blotting clearly demonstrated that p38 MAPK, JNK and p42/p44 ERK were activated by IL-17 in HASMC. Using SB203580, a specific inhibitor of p38 MAPK, we detected a concentration-dependent inhibition of IL-17--induced IL-8 production with a maximal decrease of 63 +/- 5% (n=8, p<0.01). Curcumin, a specific inhibitor of JNK, also concentration-dependently reduced IL-17--induced IL-8 production, with a maximal decrease of 82+/-4% (n=8, p<0.01). U0126, a specific inhibitor of p42/p44 ERK, induced a maximal decrease of 84+/-5% (n=8, p<0.001). Pyrrolydine dithiocarbamate (PDTC), an inhibitor of NF-kappaB, caused a 70+/-5% (n=8, p<0.01) decrease in IL-17--induced IL-8 production.

CONCLUSIONS

We found that IL-17 induces activation of p38MAPK, JNK and p42/p44ERK in HASMC. We also found that p38MAPK, JNK, p42/p44 ERK and NF-kappaB play an important role in IL-17--induced IL-8 production in HASMC in vitro. This may open up new opportunities for further treatment of this disease.

The interrelationship between markers of inflammation and oxidative stress in chronic obstructive pulmonary disease: modulation by inhaled steroids and antioxidant

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is accompanied by both airway and systemic inflammation and by oxidative stress. This study aimed to characterise the relationship between oxidative stress and inflammatory components in induced sputum and blood.

MATERIAL & METHODS

We studied blood and sputum samples from stable COPD patients (mean FEV1 60.5+/-7.5% predicted) at baseline (no treatment) and after 10 weeks treatment with either inhaled steroid, fluticasone propionate (FP) (1000 microg/d) or 10 weeks treatment with N-acetylcysteine (600mg/d) (NAC). We assessed the inflammatory markers (IL-8, ECP, sICAM-1, NE) in sputum and serum and we compared them with blood markers of oxidative stress (SOD, GPx, TEAC, albumin, vitamin E and A).

RESULTS

At baseline blood sICAM-1 correlated with IL-8 levels (P<0.01, r = 0.62) and negatively with GPx (P<0.01, r = -0.63) and with TEAC (P<0.05, r = -0.53). TEAC correlated positively with GPx (P<0.01, r = 0.70). Correlation between sICAM and IL-8 disappeared after NAC treatment. The correlation between sICAM and GPx disappeared after FP treatment. The correlation between TEAC and GPx was maintained after both NAC and FP.

CONCLUSIONS

The relationship between markers of inflammation, adhesion and antioxidant capacity is significantly modulated by treatment with N-acetylcysteine or inhaled corticosteroids.

Nitrosative Stress, Heme Oxygenase-1 Expression and Airway Inflammation During Severe Exacerbations of COPD

STUDY OBJECTIVES

The aim of this study was to examine the relationship between airway inflammation, nitrosative stress, heme-oxygenase expression, and acute severe exacerbations of COPD.

DESIGN

We measured heme oxygenase (HO)-1, inducible nitric oxide (NO) synthase expression and nitrotyrosine formation, as well as eosinophilic cationic protein, myeloperoxidase (MPO), interleukin (IL-8), and granulocyte macrophage-colony stimulating factor levels in induced sputum samples from 12 COPD patients (mean +/- SD; FEV1 40 +/- 14% predicted) at the onset of an acute severe exacerbation of COPD requiring hospital admission and 16 weeks after remission.

RESULTS

We demonstrated increased percentages (p = 0.001) and absolute numbers (p = 0.028) of total nitrotyrosine positive (+ve) inflammatory cells (ie, polymorphonuclear cells and macrophages), increased percentages (p = 0.04) and absolute numbers (p = 0.05) of total HO-1 +ve inflammatory cells, and increased MPO (p = 0.005) and IL-8 levels (p = 0.028) during severe exacerbation compared with the stable state.

CONCLUSIONS

Our results support the hypothesis of an involvement of inflammatory and nitrosative stress in severe COPD exacerbations. Future therapeutic strategies may aim at regulating inflammation and NO synthesis during COPD exacerbations.

Inhaled corticosteroid effects both eosinophilic and non-eosinophilic inflammation in asthmatic patients

AIM: To determine induced sputum cell counts and interleukin-8 (IL-8), tumor necrosis factor alpha (TNF-alpha) and leukotriene B4 (LTB4) levels as markers of neutrophilic inflammation in moderate persistent asthma, and to evaluate the response to inhaled steroid therapy. METHODS: Forty-five moderate asthmatic patients and 10 non-smoker controls were included in this study. All patients received inhaled corticosteroid (800 microg of budesonide) for 12 weeks. Before and after treatment pulmonary function tests were performed, and symptom scores were determined. Blood was drawn for analysis of serum inflammatory markers, and sputum was induced. RESULTS: Induced sputum cell counts and inflammatory markers were significantly higher in patients with asthma than in the control group. The induced sputum eosinophil counts of 12 patients (26%) were found to be less than 5%, the non-eosinophilic group, and sputum neutrophil counts, IL-8 and TNF-alpha levels were significantly higher than the eosinophilic group (neutrophil, 50+/-14% versus 19+/-10%, p<0.01). In both groups, there was a significant decrease in sputum total cell counts and serum and sputum IL-8, TNF-alpha and LTB4 levels after the treatment. There was no change in sputum neutrophil counts. Although the sputum eosinophil count decreased only in the eosinophilic subjects, there was no significant difference in inflammatory markers between the groups. The symptom scores were significantly improved after treatment, while the improvement did not reach statistical significance on pulmonary function test parameters. CONCLUSION: Notably, in chronic asthma there is a subgroup of patients whose predominant inflammatory cells are not eosinophils. Sputum neutrophil counts and neutrophilic inflammatory markers are significantly higher in these patients. In the non-eosinophilic group, inhaled steroid caused an important decrease in inflammatory markers; however, there was no change in the sputum eosinophil and neutrophil counts.

Haemophilus influenzae from patients with chronic obstructive pulmonary disease exacerbation induce more inflammation than colonizers

RATIONALE

Airway infection with Haemophilus influenzae causes airway inflammation, and isolation of new strains of this bacteria is associated with increased risk of exacerbations in patients with chronic obstructive pulmonary disease (COPD).

OBJECTIVE

To determine whether strains of H. influenzae associated with exacerbations cause more inflammation than strains that colonize the airways of patients with COPD.

METHODS

Exacerbation strains of H. influenzae were isolated from patients during exacerbation of clinical symptoms with subsequent development of a homologous serum antibody response and were compared with colonization strains that were not associated with symptom worsening or an antibody response. Bacterial strains were compared using an in vivo mouse model of airway infection and in vitro cell culture model of bacterial adherence and defense gene and signaling pathway activation in primary human airway epithelial cells.

RESULTS

H. influenzae associated with exacerbations caused more airway neutrophil recruitment compared with colonization strains in the mouse model of airway bacterial infection. Furthermore, exacerbation strains adhered to epithelial cells in significantly higher numbers and induced more interleukin-8 release after interaction with airway epithelial cells. This effect was likely mediated by increased activation of the nuclear factor-kappaB and p38 mitogen-activated protein kinase signaling pathways.

CONCLUSIONS

The results indicate that H. influenzae strains isolated from patients during COPD exacerbations often induce more airway inflammation and likely have differences in virulence compared with colonizing strains. These findings support the concept that bacteria infecting the airway during COPD exacerbations mediate increased airway inflammation and contribute to decreased airway function.

Airway function and markers of airway inflammation in patients with treated hypothyroidism

BACKGROUND

There is increasing evidence of an association between organ specific autoimmune diseases, particularly autoimmune thyroid disease and respiratory morbidity. A study was undertaken to determine whether patients with autoimmune thyroid disease have objective evidence of airway inflammation and dysfunction.

METHODS

Twenty six non-smoking women with treated hypothyroidism and 19 non-smoking controls completed a symptom questionnaire and underwent full lung function tests, capsaicin cough reflex sensitivity measurement, methacholine challenge test, and sputum induction over two visits.

RESULTS

Symptoms of cough (p = 0.01), dyspnoea (p = 0.01), sputum production (p = 0.004), and wheeze (p = 0.04) were reported more commonly in patients than controls. Patients with hypothyroidism had heightened cough reflex sensitivity compared with controls (geometric mean concentration of capsaicin causing five coughs: 40 v 108 mmol/l; mean difference 1.4 doubling doses; 95% confidence interval of difference 0.4 to 2.5; p = 0.008) and a significantly higher proportion of patients had airway hyperresponsiveness (methacholine provocative concentration (PC(20)) <8 mg/ml: 38% v 0%; p = 0.016). Patients with hypothyroidism also had a significantly higher induced sputum total neutrophil cell count (p = 0.01), total lymphocyte count (p = 0.02), and sputum supernatant interleukin-8 concentrations (p = 0.048).

CONCLUSION

Patients with treated hypothyroidism report more respiratory symptoms and have objective evidence of airway dysfunction and inflammation.

Lipid peroxidation and 5-lipoxygenase activity in chronic obstructive pulmonary disease

We studied the urinary excretion of the isoprostane 8-iso-prostaglandin F(2alpha) as an index of in vivo oxidant stress, and the production of leukotriene (LT) B(4) (LTB(4)) by neutrophils in subjects with chronic obstructive pulmonary disease (COPD) and normal subjects. Overnight urinary excretion of the isoprostane was significantly higher in patients with COPD than in control subjects, and LTB(4) production by challenge of neutrophils obtained from patients with COPD was also significantly higher than that observed in control neutrophils. Treatment with a standardized polyphenol extract caused a significant decrease in isoprostane excretion, accompanied by a statistically significant increase of Pa(O(2)). Furthermore, changes in FEV(1) significantly correlated with the changes in isoprostane urinary excretion observed from enrollment to the end of treatment. The results of this study suggest that enhanced oxidative stress in subjects with COPD is paralleled by the increased ability of neutrophils to synthesize the chemotactic factor LTB(4), and may ultimately contribute to the infiltration/activation of neutrophils into the airways of subjects with COPD. Antioxidant treatment in subjects with COPD is effective in reducing oxidant stress as shown by the decrease of urinary isoprostane, a reduction that correlates with the severity of the disease, as indicated by changes in Pa(O(2)) and FEV(1).

Efficacy and safety of a monoclonal antibody recognizing interleukin-8 in COPD: a pilot study

STUDY OBJECTIVE

To investigate the efficacy and safety of a fully human monoclonal antibody recognizing the chemokine interleukin (IL)-8 in patients with COPD.

DESIGN

Randomized, double-blind, parallel-group, placebo-controlled trial.

SETTING

Eighteen clinics/hospitals in the United States.

PATIENTS

One hundred nine patients with stable COPD.

INTERVENTIONS

Three IV infusions of either monoclonal antibody recognizing IL-8 (800-mg loading dose; 400-mg subsequent doses) or active buffer solution administered monthly over a 3-month period.

MEASUREMENTS AND RESULTS

The differences in the transition dyspnea index (TDI) total score, the primary outcome measure, between fully human monoclonal IgG(2) antibody directed against IL-8 and placebo were 0.8, 1.0, 0.8, and 0.3 at week 2 (p = 0.046) and months 1 to 3, respectively. At all time points, the proportion of patients achieving >/= 1 point improvement in the TDI was greater for the monoclonal antibody group compared with the placebo group: 28% vs 11% at week 2 (p = 0.028). There were no significant differences observed for lung function, health status, 6-min walking distance, and adverse events between groups.

CONCLUSIONS

The results of this phase 2 study suggest that neutralization of IL-8 with monoclonal antibody therapy may improve dyspnea in patients with COPD. These results support the further investigation of monoclonal antibody therapy targeting IL-8 for the treatment of this disease.

Prospects for new drugs for chronic obstructive pulmonary disease

No currently available treatments have been shown to slow the progression of chronic obstructive pulmonary disease (COPD) or suppress the inflammation in small airways and lung parenchyma. However, several new treatments are in clinical development; some target the inflammatory process and others are directed against structural cells. A group of specific therapies are directed against the influx of inflammatory cells into the airways and lung parenchyma that occurs in COPD; these include agents directed against adhesion molecules and chemokines, as well as therapies to oppose tumour necrosis factor alpha and increase interleukin 10. Broad-range anti-inflammatory drugs are now in phase III development for COPD; they include inhibitors of phosphodiesterase 4. Other drugs that inhibit cell signalling include inhibitors of p38 mitogen-activated protein kinase, nuclear factor kappaB, and phosphoinositide-3-kinase gamma. More specific approaches are to give antioxidants, inhibitors of inducible nitric oxide synthase, and antagonists of leukotriene B4 receptor. Inhibitors of epidermal-growth-factor-receptor kinase and calcium-activated chloride channels have the potential to prevent overproduction of mucus. Therapy to inhibit fibrosis is being developed against transforming growth factor beta1 and protease-activated receptor 2. There is also a search for inhibitors of serine proteinases and matrix metalloproteinases to prevent lung destruction and the development of emphysema, as well as drugs such as retinoids that might even reverse this process. Effective delivery of drugs to the sites of disease in the peripheral lung is an important consideration, and there is a need for validated biomarkers and monitoring techniques in early clinical studies with new therapies for COPD.

The Effect of Clarithromycin on Inflammatory Markers in Chronic Obstructive Pulmonary Disease: Preliminary Data

BACKGROUND:

Clarithromycin is an antimicrobial agent that can be used for treatment of chronic obstructive pulmonary disease (COPD) exacerbations with bronchodilator therapy. However, it has also been shown that clarithromycin has antiinflammatory effects by the inhibition of cytokine production.

OBJECTIVE:

To evaluate the antiinflammatory effect of clarithromycin on serum and sputum interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α), and leukotriene B4 levels in patients with COPD.

METHODS:

Thirty men with mild to moderate COPD were enrolled in this prospective, single-center, double-blind, placebo-controlled study. None of the patients was receiving systemic or inhaled corticosteroids during the study. Subjects received either clarithromycin or placebo for 14 days. Before and after this treatment period, spirometric tests and arterial blood gas analysis were performed, blood was drawn for measurement of serum inflammatory markers, and sputum was induced.

RESULTS:

There were no statistically significant differences in baseline clinical or laboratory parameters between the groups. After the treatment, the induced sputum total cell counts, and IL-8 and TNF-α levels decreased significantly in the clarithromycin group compared with pretreatment levels (mean ± SD IL-8 1606 ± 367.3 vs 882 ± 143.6 pg/mL, p = 0.001; TNF-α 638.2 ± 287.5 vs 390 ± 235 pg/mL, p = 0.001). Similarly, decreases in serum inflammatory markers were found in the clarithromycin group while there was no significant change in the placebo group.

CONCLUSIONS:

This study demonstrated that the decrease in IL-8 and TNF-α levels might be related to the antiinflammatory effect of clarithromycin. Thus, we suggest that the use of clarithromycin in COPD exacerbations may either treat the infection or help control the inflammation. Future studies are needed to determine the clinical significance of these findings.

Effects of hydrogen peroxide on MAPK activation, IL-8 production and cell viability in primary cultures of human bronchial epithelial cells

The airway epithelium is continuously exposed to inhaled oxidants, including airborne pollutants and cigarette smoke, which can exert harmful proinflammatory and cytotoxic effects. Therefore, the aim of our study was to investigate, in primary cultures of human bronchial epithelial cells (HBEC), the signal transduction pathways activated by increasing concentrations (0.25, 0.5, and 1 mM) of hydrogen peroxide (H(2)O(2)), as well as their effects on IL-8 production and cell viability. The reported results show that H(2)O(2) elicited, in a concentration-dependent fashion, a remarkable increase in phosphorylation-dependent activation of mitogen-activated protein kinases (MAPKs), associated with a significant induction of IL-8 synthesis and a dramatically enhanced cell death. Pre-treatment of HBEC with MAPK inhibitors was able to significantly inhibit the effects of H(2)O(2) on IL-8 secretion, and to effectively prevent cell death. Therefore, these findings suggest that MAPKs play a key role as molecular transducers of the airway epithelial injury triggered by oxidative stress, as well as potential pharmacologic targets for indirect antioxidant intervention.