Bianca Beghé

Complex chronic comorbidities of COPD

Chronic obstructive pulmonary disease (COPD) is defined by fixed airflow limitation associated with an abnormal pulmonary and systemic inflammatory response of the lungs to cigarette smoke. The systemic inflammation induced by smoking may also cause chronic heart failure, metabolic syndrome and other chronic diseases, which may contribute to the clinical manifestations and natural history of COPD. Thus COPD can no longer be considered a disease only of the lungs, as it is often associated with a wide variety of systemic consequences. A better understanding of the origin and consequences of systemic inflammation, and of potential therapies, will most likely lead to better care of patients with COPD. Medical textbooks and clinical guidelines still largely ignore the fact that COPD seldom occurs in isolation. As the diagnosis and assessment of severity of COPD may be greatly affected by the presence of comorbid conditions, the current authors believe that lung function measurement, noninvasive assessment of cardiovascular and metabolic functions, and circulating inflammatory markers (e.g. C-reactive protein) might help to better characterise these patients. Similarly, preventive and therapeutic interventions should address the patient in their complexity.

Polymorphisms in the interleukin-4 and interleukin-4 receptor alpha chain genes confer susceptibility to asthma and atopy in a Caucasian population

Background  IL‐4 by binding to its receptor (IL‐4R) is essential for the development of airway inflammation present in asthma, through the induction of IgE synthesis in B cells and differentiation of T cells to a Th2 phenotype.

Neutrophilic infiltration within the airway smooth muscle in patients with COPD

Background: COPD is an inflammatory disorder characterised by chronic airflow limitation, but the extent to which airway inflammation is related to functional abnormalities is still uncertain. The interaction between inflammatory cells and airway smooth muscle may have a crucial role. Methods: To investigate the microlocalisation of inflammatory cells within the airway smooth muscle in COPD, surgical specimens obtained from 26 subjects undergoing thoracotomy (eight smokers with COPD, 10 smokers with normal lung function, and eight non-smoking controls) were examined. Immunohistochemical analysis was used to quantify the number of neutrophils, macrophages, mast cells, CD4+ and CD8+ cells localised within the smooth muscle of peripheral airways. Results: Smokers with COPD had an increased number of neutrophils and CD8+ cells in the airway smooth muscle compared with non-smokers. Smokers with normal lung function also had a neutrophilic infiltration in the airway smooth muscle, but to a lesser extent. When all the subjects were analysed as one group, neutrophilic infiltration was inversely related to forced expiratory volume in 1 second (% predicted). Conclusions: Microlocalisation of neutrophils and CD8+ cells in the airway smooth muscle in smokers with COPD suggests a possible role for these cells in the pathogenesis of smoking induced airflow limitation.

Marked alveolar apoptosis/proliferation imbalance in end-stage emphysema.

BackgroundApoptosis has recently been proposed to contribute to the pathogenesis of emphysema.MethodsIn order to establish if cell fate plays a role even in end-stage disease we studied 16 lungs (9 smoking-associated and 7 α1antitrypsin (AAT)-deficiency emphysema) from patients who had undergone lung transplantations. Six unused donor lungs served as controls. Apoptosis was evaluated by TUNEL analysis, single-stranded DNA laddering, electron microscopy and cell proliferation by an immunohistochemical method (MIB1). The role of the transforming growth factor (TGF)-β1 pathway was also investigated and correlated with epithelial cell turnover and with the severity of inflammatory cell infiltrate.ResultsThe apoptotic index (AI) was significantly higher in emphysematous lungs compared to the control group (p ≤ 0.01), particularly if only lungs with AAT-deficiency emphysema were considered (p ≤ 0.01 vs p = 0.09). The proliferation index was similar in patients and controls (1.9 ± 2.2 vs 1.7 ± 1.1). An increased number of T lymphocytes was observed in AAT-deficiency lungs than smoking-related cases (p ≤ 0.05). TGF-β1 expression in the alveolar wall was higher in patients with smoking-associated emphysema than in cases with AAT-deficiency emphysema (p ≤ 0.05). A positive correlation between TGF-βRII and AI was observed only in the control group (p ≤ 0.005, r2 = 0.8). A negative correlation was found between the TGF-β pathway (particularly TGF-βRII) and T lymphocytes infiltrate in smoking-related cases (p ≤ 0.05, r2 = 0.99)ConclusionOur findings suggest that apoptosis of alveolar epithelial cells plays an important role even in end-stage emphysema particularly in AAT-deficiency disease. The TGFβ-1 pathway does not seem to directly influence epithelial turnover in end-stage disease. Inflammatory cytokine different from TGF-β1 may differently orchestrate cell fate in AAT and smoking-related emphysema types.

The genetic basis of atopic asthma.

Asthma is a respiratory disease characterized by recurrent respiratory symptoms, reversible variable airway obstruction, airway inflammation and increased airway responsiveness [1]. Atopy is a disorder involving immunoglobulin E (IgE) antibody responses to ubiquitous allergens, and is commonly associated with asthma. Because of its complex clinical phenotype, the genetic basis of asthma can be studied using intermediate or surrogate phenotypes that can be measured objectively, such as the presence of atopy or bronchial hyperresponsiveness (BHR), although these are not specific to asthma. Furthermore, despite the close relationship between atopy, bronchial hyperresponsiveness and asthma [2–4], they are not interchangeable: most asthmatics are atopic, but atopic subjects may not have bronchial hyperresponsiveness or asthma symptoms and subjects with bronchial hyperresponsiveness may not be atopic or asthmatic (see Fig. 1). The phenotype can be defined in several ways ranging from subjective measures (e.g. symptoms), objective measures (e.g. BHR or serum IgE level) or both. It is this lack of a clear definition of asthmatic phenotypes that presents the biggest problem when reviewing studies of the genetic basis of asthma and atopy, with multiple definitions of the same intermediate phenotype being used in different studies.

Allelic association and functional studies of promoter polymorphism in the leukotriene C4 synthase gene (LTC4S) in asthma

Background: LTC4 synthase is essential for the production of cysteinyl leukotrienes (Cys-LT), critical mediators in asthma. We have identified a novel promoter polymorphism at position −1072 (G/A) and a −444 (A/C) polymorphism has previously been reported. The role of these polymorphisms in the genetic susceptibility to asthma was examined. Methods: To test for genetic association with asthma phenotypes, 341 white families (two asthmatic siblings) and 184 non-asthmatic control subjects were genotyped. Genetic association was assessed using case control and transmission disequilibrium test (TDT) analyses. LTC4S promoter luciferase constructs and transiently transfected human HeLa and KU812F cells were generated to determine the functional role of these polymorphisms on basal transcription. Results: No associations were observed in case control analyses (–1072 A, q=0.09; −444 C, q=0.29); the TDT identified a borderline association between the −444 C allele and bronchial responsiveness to methacholine (p=0.065). Asthmatic children with the −444 C allele had a lower mean basal forced expiratory volume in 1 second (97.4 v 92.7% predicted, p=0.005). LTC4S promoter luciferase analyses provided no evidence for a functional role of either polymorphism in determining basal transcription. Conclusion: This study does not support a role for these polymorphisms in genetic susceptibility to asthma but provides evidence to suggest a role in determining lung function parameters.

Polymorphisms in IL13 pathway genes in asthma and chronic obstructive pulmonary disease

To cite this article: Beghé B, Hall IP, Parker SG, Moffatt MF, Wardlaw A, Connolly MJ, Fabbri LM, Ruse C, Sayers I. Polymorphisms in IL13 pathway genes in asthma and chronic obstructive pulmonary disease. Allergy 2010; 65: 474–481.

Phosphodiesterase-4 Inhibitor Therapy for Lung Diseases

Phosphodiesterases (PDEs) are a superfamily of enzymes that catalyze the breakdown of cAMP and/or cyclic guanosine monophosphate (GMP) to their inactive form. PDE4 is the main selective cAMP-metabolizing enzyme in inflammatory and immune cells. Because PDE4 is highly expressed in leukocytes and other inflammatory cells involved in the pathogenesis of inflammatory lung diseases, such as asthma and chronic obstructive pulmonary disease (COPD), inhibition of PDE4 has been predicted to have an antiinflammatory effect and thus therapeutic efficacy. The limited and inconsistent efficacy and side effects of the early compounds made their further development less desirable in asthma, given the excellent efficacy/tolerability ratio of inhaled steroids. The lack of effective antiinflammatory drug treatment for COPD has thus shifted the interest in development toward COPD. Roflumilast, the only PDE4 inhibitor that has reached the market because of the good efficacy/tolerability ratio, is recommended for patients with COPD with severe airflow limitation, symptoms of chronic bronchitis, and a history of exacerbations, whose disease is not adequately controlled by long-acting bronchodilators. Albeit safe, it maintains significant side effects (diarrhea, nausea, weight loss) that make it intolerable in some patients. Future developments of PDE4 inhibitors include extended indications of roflumilast (1) in patients with COPD, and (2) in other respiratory (e.g., asthma) and nonrespiratory chronic inflammatory/metabolic conditions (e.g., diabetes), as well as (3) the development of new molecules with PDE4 inhibitory properties with an improved efficacy/tolerability profile.

Promoter polymorphism in the 5-lipoxygenase (ALOX5) and 5-lipoxygenase-activating protein (ALOX5AP) genes and asthma susceptibility in a Caucasian population

Background 5‐Lipoxygenase (5‐LO) and 5‐lipoxygenase‐activating protein (FLAP) are essential for cysteinyl‐leukotriene (cys‐LT) production, critical mediators in asthma.

Similarities and discrepancies between exacerbations of asthma and chronic obstructive pulmonary disease

Asthma is a chronic inflammatory disorder of the airways which causes recurrent episodes of wheezing, breathlessness, chest tightness, and cough, symptoms which are usually associated with reversible airflow limitation.1 2 This definition includes the recurrence of respiratory symptoms which might be otherwise classified as asthma exacerbations. However, the term asthma exacerbation is usually reserved for more severe and/or more persistent respiratory symptoms requiring a prolonged increase of current antiasthma medication.1 2 Chronic obstructive pulmonary disease (COPD) is defined as a progressive airflow limitation, mostly irreversible.3 4 The term COPD includes patients with obstructive chronic bronchitis and/or pulmonary emphysema.3 4 Patients with moderate or severe persistent asthma may also have an irreversible component of airflow limitation, and thus they may also be included in the definition of COPD.3 The definition of COPD does not include exacerbations,3-5 even if exacerbations are the main cause of medical intervention and admission to hospital in these patients. Recent guidelines provide classifications of exacerbations of asthma and COPD based on clinical parameters.1-4 6Although these classifications may provide a useful tool for clinical studies, they are not standardised and they are rather cumbersome and difficult to use in clinical practice. The definitions derived from the literature are operational and vary with investigators.7-14 In this article we will try to provide some definitions to be subsequently used to discuss the pathogenesis and treatment of the two diseases. Mild exacerbations of asthma may be defined as increased intensity or frequency of symptoms and/or worsened lung function—that is, decreased forced expiratory flows or increased variability of peak expiratory flow—that force the patient either to change prescribed treatment and/or to seek medical attention.13 14 The borderline between ongoing symptoms with frequent use of rescue medication and mild exacerbations may be difficult …