Graziella Turato

Increased activation of p38 MAPK in COPD

Inflammation, oxidative stress and apoptosis, which are involved in chronic obstructive pulmonary disease (COPD) pathogenesis, may activate the p38 subgroup of mitogen-activated protein kinases (MAPKs). Therefore, the aim of the present study was to evaluate the expression of the phosphorylated, active form of p38 MAPK (phospho-p38) in the lungs of COPD patients. Surgical specimens were obtained from 18 smokers with COPD at different stages of disease severity, plus nine smoking and eight nonsmoking subjects with normal lung function. Phospho-p38+ cells were quantified by immunohistochemistry in both alveolar spaces and alveolar walls. Moreover, a Western blot analysis of phospho-p38 and total p38α isoform expressed by alveolar macrophages was performed. Phospho-p38+ alveolar macrophages and phospho-p38+ cells in alveolar walls were increased in patients with severe and mild/moderate COPD, compared with smoking and nonsmoking controls. Moreover, they were inversely correlated to values of forced expiratory volume in one second (FEV1) and FEV1/forced vital capacity. Western blot analysis showed that phosphorylated p38, but not the total p38α isoform, was specifically increased in alveolar macrophages from COPD patients. Activation of the p38 mitogen-activated protein kinase pathway appears to be involved in the pathogenesis of chronic obstructive pulmonary disease. The present findings suggest that this protein may be a suitable pharmacological target for therapeutic intervention.

IL-32, a novel proinflammatory cytokine in chronic obstructive pulmonary disease.

RATIONALE Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disorder of the lung, yet the mechanisms that regulate this immune-inflammatory response are not fully understood. OBJECTIVES We investigated whether IL-32, a newly discovered cytokine, was related to markers of inflammation and clinical progression in COPD. METHODS Using immunohistochemistry, expression of IL-32 was examined in surgically resected specimens from 40 smokers with COPD (FEV(1) = 39 +/- 4% predicted), 11 smokers with normal lung function, and 9 nonsmoking control subjects. IL-32 was quantified in alveolar macrophages, alveolar walls, bronchioles, and arterioles, and confirmed by molecular analysis. The levels of IL-32 were correlated with the cellular infiltrates, markers of inflammation, and clinical data. MEASUREMENTS AND MAIN RESULTS Macrophage staining for IL-32 was increased in smokers with COPD compared with control smokers and nonsmokers (P = 0.0014 and P < 0.0001, respectively), and similar differences were observed in alveolar walls (P = 0.0004 and P = 0.0005) and bronchiolar epithelium (P = 0.004 and P = 0.0009). This increase was also detected at the mRNA level (P = 0.007 vs. control smokers and P = 0.029 vs. nonsmokers) and was mainly due to non-alpha isoforms. Moreover, IL-32 expression was positively correlated with tumor necrosis factor-alpha (P = 0.004, r(s)=0.70), CD8(+)cells (P = 0.02, r(s)=0.46), phospho p38MAPK (P < 0.01, r(s)=0.60) and negatively with FEV(1) values (P = 0.004, r(s)= -0.53). CONCLUSIONS This is the first study to demonstrate increased expression of IL-32 in lung tissue of patients with COPD, where it was colocalized with tumor necrosis factor-alpha and correlated with the degree of airflow obstruction. These results suggest that IL-32 is implicated in the characteristic immune response of COPD, with a possible impact on disease progression.

Airway eosinophilia and expression of interleukin-5 protein in asthma and in exacerbations of chronic bronchitis

Background An increased nutnber of eosinophils in the bronchial mucosa has been demonstrated both in asthma and in exacerbations of chronic bronchitis. Oiyective To investigate whether the airway eosinophilia present in asthma and in chronic bronchitis during exacerbations is associated with interleukin (IL)‐5 protein expression in the bronchial mucosa.

Decreased haem oxygenase-1 and increased inducible nitric oxide synthase in the lung of severe COPD patients

Oxidant/antioxidant imbalance is implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). The current study examined the expression of antioxidant and pro-oxidant enzymes, haem oxygenases (HO) and inducible nitric oxide synthase (iNOS) respectively, in patients with severe COPD and control smokers without lung function impairment. Immunoreactivity for HO-1, HO-2, iNOS and nitric oxide-derived oxidants expressed as nitrotyrosine (N-Tyr) was quantified in peripheral lung. HO-1+ alveolar macrophages were decreased in severe COPD compared to control smokers, whereas no difference was observed in iNOS+ macrophages. In contrast, severe patients had significantly higher numbers of iNOS+ cells in alveolar walls. These iNOS+ cells were identified as type 2 pneumocytes and their number was inversely related to HO-1+ macrophages. There were no significant differences in N-Tyr immunostaining between the two groups. However, the rate of protein nitration in lungtissue was directly related to iNOS expression and associated with lower valuesofforced expiratory volume in one second/forced vital capacity. HO-2 was constitutively expressed by type 2 pneumocytes and these cells were increased in severe COPD. In conclusion, the results suggest that the enzymes involved in the oxidative stressresponse may have a different role in the lung defence and that imbalance betweenhaemoxygenase-1 and inducible nitric oxide synthase may be associated withthe development of severe impairment in chronic obstructive pulmonary disease patients.

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.

Nonatopic Children with Multitrigger Wheezing Have Airway Pathology Comparable to Atopic Asthma

RATIONALE Epidemiologic studies have shown that, in atopic children, wheezing is more likely to persist into adulthood, eventually becoming asthma, whereas it appears to resolve by adolescence in nonatopic children. OBJECTIVES To investigate whether among children with multitrigger wheeze responsive to bronchodilators the airway pathology would be different in nonatopic wheezers, who are often considered nonasthmatic, compared with atopic wheezers, who are more frequently diagnosed as having asthma. METHODS Bronchial biopsies were obtained from 55 children undergoing bronchoscopy for appropriate clinical indications: 18 nonatopic children with multitrigger wheeze (median age, 5 yr; range, 2-10 yr), 20 atopic children with multitrigger wheeze (medan age, 5 yr; range, 2-15 yr), and 17 control children with no atopy or wheeze (median age, 4; range, 2-14 yr). By histochemistry and immunohistochemistry, we quantified epithelial loss, basement membrane thickness, angiogenesis, inflammatory cells, IL-4(+,) and IL-5(+) cells in subepithelium. MEASUREMENTS AND MAIN RESULTS Unexpectedly, all pathologic features examined were similar in atopic and nonatopic wheezing children. Compared with control subjects, both nonatopic and atopic wheezing children had increased epithelial loss (P = 0.03 and P = 0.002, respectively), thickened basement membrane (both P < 0.0001), and increased number of vessels (P = 0.003 and P = 0.03, respectively) and eosinophils (P < 0.0001 and P = 0.002, respectively). Moreover, they had increased cytokine expression, which was highly significant for IL-4 (P = 0.002 and P = 0.0001, respectively) and marginal for IL-5 (P = 0.02 and P = 0.08, respectively). CONCLUSIONS This study shows that the airway pathology typical of asthma is present in nonatopic wheezing children just as in atopic wheezing children. These results suggest that, when multitrigger wheezing responsive to bronchodilators is present, it is associated with pathologic features of asthma even in nonatopic children.

Pathogenesis and Pathology of COPD

Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation. Since flow is the result of a driving pressure that promotes flow and of an opposing resistance that contradicts it, the reduction in flow observed in COPD has two main components: increased resistance, which is due to airway obstruction, and a loss of the elastic recoil pressure of the lung, which is due to parenchymal destruction. Although it has long been known that the major site of increased resistance in COPD is the peripheral airways, recent studies have shown that central airways are involved in the disease as well. The purpose of this review is to describe the major structural and cellular changes present in peripheral airways, central airways and lung parenchyma of patients with COPD, and to underline the possible mechanisms contributing to airflow limitation in these subjects.

Fixed airflow obstruction due to asthma or chronic obstructive pulmonary disease: 5-year follow-up

BACKGROUND Both smokers and patients with asthma can experience fixed airflow obstruction, which is associated with distinctive patterns of airway pathology. The influence of fixed airflow obstruction on the prognosis of these patients is unknown. OBJECTIVE We sought to investigate lung function decline and exacerbations in a 5-year prospective study of subjects with fixed airflow obstruction due to asthma or chronic obstructive pulmonary disease (COPD). We also sought to explore correlations between functional, pathological, and clinical features. METHODS Patients with fixed airflow obstruction due to asthma (n = 16) or COPD (n = 21) and a control group of asthmatic patients with fully reversible airflow obstruction (n = 15) were followed for 5 years. RESULTS The rates of decline in FEV(1) were similar in patients with fixed airflow obstruction caused by asthma (-49.7 +/- 10.6 mL/y) or COPD (-51.4 +/- 9.8 mL/y) and were higher than in asthmatic patients with reversible airflow obstruction (-18.1 +/- 10.1 mL/y, P < .01). Exacerbation rates were also higher in patients with fixed airflow obstruction caused by asthma (1.41 +/- 0.26 per patient-year) or COPD (1.98 +/- 0.3 per patient-year) compared with those seen in asthmatic patients with reversible airflow obstruction (0.53 +/- 0.11 per patient-year, P < .01). Baseline exhaled nitric oxide levels and sputum eosinophil counts correlated with the FEV(1) decline in asthmatic patients with fixed airflow obstruction. By contrast, baseline sputum neutrophil counts, emphysema scores, comorbidities, and exacerbation frequency correlated directly and pulmonary diffusion capacity correlated inversely with the FEV(1) decline in patients with COPD. CONCLUSION In both patients with asthma and those with COPD, fixed airflow obstruction is associated with increased lung function decline and frequency of exacerbations. Nevertheless, the decline in lung function entails the specific pathological and clinical features of the underlying diseases.

Expression of interleukin (IL)-4 and IL-5 proteins in asthma induced by toluene diisocyanate (TDI).

Background TDI‐induced asthma exhibits clinical, functional and morphological similarities with allergen‐induced asthma, suggesting that an immunological mechanism is involved in the sensitization to TDL In vitro studies using the technique of cloning lymphocytes demonstrated that a great proportion of T‐cell clones derived from bronchial mucosa of subjects with TDI‐induced asthma produced IL‐5 and interferon‐gamma, but not IL‐4, upon in vitro stimulation.

Pathophysiology of the Small Airways in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is characterized by a persistent airflow limitation that is usually progressive and associated with an enhanced chronic inflammatory response in the airways and the lung to noxious particles or gases. From a pathological point of view, COPD is characterized by two distinct and frequently coexisting aspects: small airway abnormalities and parenchymal destruction (or emphysema). When pathological changes are localized in lung parenchyma, they will contribute to airflow limitation by reducing the elastic recoil of the lung through parenchymal destruction, as well as by reducing the elastic load applied to the airways through destruction of alveolar attachments. Conversely, when pathological changes involve the small airways, they will contribute to airflow limitation by narrowing and obliterating the lumen and by actively constricting the airways, therefore increasing the resistance. In this article we will review the structural abnormalities in small airways and their relationship with the disordered pulmonary function in COPD, in the attempt to disentangle the mechanisms contributing to the development and progression of airflow limitation in smokers. We will start by describing the normal structure of the small airways, and then observe the main pathological alterations that accumulate in this site and how they parallel pulmonary function derangement.