Noneosinophilic asthma in children: relation with airway remodelling.

Noneosinophilic asthma is increasingly recognised as an important clinical-pathological phenotype in adults. However, this entity has scarcely been investigated in children. In particular, it is unknown whether airway remodelling would develop in children with non-eosinophilic asthma to the same degree as in children with eosinophilic disease. We analysed bronchial biopsies from 80 children undergoing bronchoscopy for appropriate clinical indications: 21 with noneosinophilic asthma, 34 with eosinophilic asthma and 25 control children. Features of airway remodelling - basement membrane thickening, epithelial loss and angiogenesis - and immune activation - inflammatory infiltrate, interleukin (IL)-4, IL-5, transforming growth factor (TGF)-ß, TGF-ß receptor type II - were quantified by histology and immunohistochemistry. The main components of airway remodelling were present in children with noneosinophilic asthma just as in those with eosinophilic disease. Indeed, compared with control children, both noneosinophilic and eosinophilic asthmatic children had thickened basement membrane, increased epithelial loss and higher number of vessels. Moreover, in both groups of asthmatics, expression of IL-4 and IL-5 was increased, while that of TGF-ß receptor type II was reduced, compared with controls. This study demonstrates that structural changes typical of asthma develop in asthmatic children even in the absence of a prominent eosinophilic infiltrate, indicating that other mechanisms, besides eosinophilic inflammation, may promote airway remodelling early in life.

Markers of eosinophilic and neutrophilic inflammation in bronchoalveolar lavage of asthmatic and atopic children.

BACKGROUND: Recent studies performing fiberoptic bronchoscopy in children have improved our understanding of asthma pathophysiology. Eosinophilic, but also neutrophilic, inflammation has been described in asthma, but the relationship with atopy was incompletely investigated. The aim of this study is to examine inflammatory cells and mediators in children with asthma compared to the appropriate controls, i.e. atopic children without asthma and children with no atopy or asthma. Moreover, asthmatic children were analysed separately based on the presence of atopy and stratified by age. METHODS: We recruited 191 children undergoing fiberoptic bronchoscopy for appropriate indications: 91 asthmatics (aged 1.4-17 years), 44 atopics without asthma (1.6-17.8 years) and 56 nonasthmatic nonatopic controls (1.4-14 years). In bronchoalveolar lavage, total and differential cell counts and inflammatory mediators, including ECP, eotaxin, IL-8 and TNFalpha, were analysed. RESULTS: Eosinophils and ECP levels were increased in asthmatic children when compared to controls (P = 0.002 and P = 0.01, respectively), but also atopic children without asthma had increased ECP levels compared to controls (P = 0.0001). Among asthmatic children, eosinophils and ECP levels were not different between atopic and nonatopic individuals. Neither neutrophils nor the related mediators (IL-8 and TNFalpha) differed significantly in the three groups. This pattern of inflammation was observed in both preschool and school-aged asthmatic children. CONCLUSIONS: This study suggests that markers of eosinophilic, but not neutrophilic inflammation, are increased in asthmatic children and also in atopic children without asthma. Of interest, in asthmatic children, the activation of the eosinophilic response is not solely because of the presence of atopy.

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 p38alpha 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 (FEV(1)) and FEV(1)/forced vital capacity. Western blot analysis showed that phosphorylated p38, but not the total p38alpha 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.

Upregulation of basic fibroblast growth factor in smokers with chronic bronchitis.

The aim of the study was to investigate the expression of basic fibroblast growth factor (bFGF) and its receptor, fibroblast growth factor receptor (FGFR)-1, in the central airways of smokers with chronic bronchitis. The lobar bronchi from 17 subjects undergoing thoracotomy for solitary nodules were examined. All had a history of cigarette smoking, nine had symptoms of chronic bronchitis and airflow limitation, and eight were asymptomatic with normal lung function. Using immunohistochemical methods, bFGF and FGFR-1 expression in the total airway wall and the different airway compartments, i.e. bronchial glands, submucosal vessels and smooth muscle, was quantified. Moreover, to investigate the role of bFGF in angiogenesis, the number of submucosal vessels was quantified. Smokers with chronic bronchitis had an increased bFGF expression in the total airway wall compared with asymptomatic smokers, which was mainly due to bFGF upregulation in bronchial glands. By contrast, the expression of FGFR-1 and the number of submucosal vessels was similar in the two groups of subjects examined. In conclusion, smokers with chronic bronchitis have an increased expression of basic fibroblast growth factor in the central airways, which is mainly due to an increased expression in bronchial glands, suggesting the involvement of this growth factor in the pathogenesis of chronic bronchitis.

Decreased expression of TGF-beta type II receptor in bronchial glands of smokers with COPD.

BACKGROUND: The role of transforming growth factor-beta1 (TGF-beta1) in chronic obstructive pulmonary disease is still controversial, but it has been proposed that it may protect from mucus hypersecretion since it is able to downregulate mucin production. A study was undertaken to investigate the expression of TGF-beta1 and its type II receptor (TGF-beta RII) in the bronchial glands of smokers with COPD. METHODS: The expression of TGF-beta(1) and TGF-beta RII were examined immunohistochemically in the bronchial glands of 24 smokers undergoing lung resection for solitary peripheral nodules: 12 with airflow limitation (smokers with COPD) and 12 with normal lung function. RESULTS: The expression of TGF-beta1 in bronchial glands was similar in the two groups of subjects while that of TGF-beta RII was lower in smokers with COPD than in smokers with normal lung function (p=0.004). TGF-beta RII expression was inversely correlated with the values of Reid's index, a measure of gland size (p=0.02, r=-0.50). CONCLUSIONS: In the bronchial glands of smokers with COPD there is decreased expression of TGF-beta RII which is associated with bronchial gland enlargement. These findings support the view that the absence of TGF-beta signalling may induce structural changes in the bronchial glands which, in turn, may promote mucus hypersecretion.

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.

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 lung tissue was directly related to iNOS expression and associated with lower values of forced 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 stress response may have a different role in the lung defence and that imbalance between haem oxygenase-1 and inducible nitric oxide synthase may be associated with the development of severe impairment in chronic obstructive pulmonary disease patients.

Exacerbations of Bronchitis: bronchial eosinophilia and gene expression for interleukin-4, interleukin-5, and eosinophil chemoattractants.

Eosinophilia has been reported during exacerbations of bronchitis, but the mechanisms of tissue recruitment of eosinophils are unclear. We quantified eosinophils and the concurrent expression of cytokines and chemokines probably responsible for the tissue eosinophilia in bronchial biopsies obtained from three groups of nonatopic subjects: (1) healthy nonsmokers (n = 7; FEV1 % predicted = 108 +/- 4 [mean +/- SEM]); (2) nonasthmatic smokers with chronic bronchitis (CB) in a stable phase of their disease (n = 11; FEV1 % predicted: 75 +/- 5); and (3) nonasthmatic subjects with CB who sought medical advice for an exacerbation of their condition (n = 9; FEV(1) % predicted: 61 +/- 8). We applied anti-EG2 antibody and immunostaining to detect and count eosinophils. We performed in situ hybridization to visualize and enumerate cells expressing the genes for interleukin (IL)-4 and IL-5 and the eosinophil chemokines eotaxin, monocyte chemoattractant protein (MCP)-4, or regulated on activation, normal T-cell expressed and secreted (RANTES). We confirmed an increase in EG2-positive eosinophils in patients with CB in exacerbation. We found messenger RNA (mRNA) positivity for IL-4 and IL-5 in CB, but the between-group differences were not statistically significant. However, the numbers of lymphomononuclear cells expressing eotaxin mRNA were significantly greater in the smokers with CB than in the healthy nonsmokers without CB (p < 0.01). Following an exacerbation, RANTES expression was upregulated and this chemokine was strongly expressed in both the surface epithelium and in subepithelial lymphomononuclear cells: only RANTES showed a significant positive correlation with the increasing number of EG2-positive cells (r = 0.51; p < 0.03). In conclusion, an allergic profile of inflammation can also occur in CB: the marked upregulation of RANTES in the epithelium and subepithelium most likely accounts for the increased eosinophilia associated with an exacerbation of bronchitis.

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.

Airway pathology in asthma.

This review focuses on the major cellular and structural changes present in the airways and lung parenchyma in asthma in comparison with chronic obstructive pulmonary disease (COPD) in an attempt to underline the possible mechanisms contributing to airflow limitation in these two diseases. Both asthma and COPD are characterized by a thickening of the airway wall and by the presence of an inflammatory process, but the inflammatory cells infiltrating the airway wall differ between the two diseases. In asthma, the most striking feature is the eosinophilic infiltration, whereas, in COPD, it is the CD8 T-lymphocytic infiltration of the airway wall. In the lung parenchyma, both diseases are characterized by an inflammatory process, whereas destruction and fibrosis of the alveolar walls occur in COPD but not in asthma. These cellular and structural changes may contribute to the development of airflow limitation (that characterizes both asthma and chronic obstructive pulmonary disease) by inducing either an increase in resistance or a decrease in driving pressure.

Biopsy techniques : optimization for collection and preservation.

Fiberoptic bronchoscopy provides a good tool to investigate bronchial biopsies, transbronchial biopsies, and bronchoalveolar lavage (BAL) in chronic inflammatory diseases such as asthma and chronic obstructive pulmonary disease (COPD) (1-8). The advantage of bronchial biopsies over other sampling techniques, such as induced sputum or BAL, is that they give anatomical information on airway morphology, therefore allowing the examination of the different compartments of the bronchial wall such as epithelium, subepithelium, smooth muscle, and glands.

Structural basis for airflow limitation in chronic obstructive pulmonary disease.

The airflow limitation that characterises chronic obstructive pulmonary disease (COPD) has two main components: an 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.

Why does airway obstruction persist in asthma due to low-molecular-weight agents? A Pathologistís view.

The pathology of occupational asthma, which is similar to that of nonoccupational asthma, is characterized by airway infiltration of eosinophils, mast cells, and T-lymphocytes associated with thickening of the subepithelial reticular basement membrane. Since occupational asthma is caused by exposure to a sensitizing agent present in the working environment, it might be expected that cessation of occupational exposure leads to complete recovery from the disease. Unfortunately, this fa orable prognosis is observed in only a small percentage of patients with occupational asthma; in most of them, symptoms and bronchial hyperresponsiveness persist, although often at a decreased level. The few longitudinal studies performed on airway pathology in subjects with occupational asthma have shown that, after cessation of exposure to the sensitizing agent, some of the pathologic alterations (such as the subepithelial collagen deposition) improve, whereas others (such as the airway eosinophilia) persist. This latter finding suggests a role for eosinophils in the persistence of symptoms and bronchial hyperresponsiveness in the majority of asthmatic subjects even several months after removal from exposure.

Goblet cell hyperplasia and epithelial inflammation in peripheral airways of smokers with both symptoms of chronic bronchitis and chronic airflow limitation.

To quantify the number of goblet cells and inflammatory cells in the epithelium of peripheral airways in smokers with both symptoms of chronic bronchitis and chronic airflow limitation, we examined surgical specimens obtained from 25 subjects undergoing lung resection for localized pulmonary lesions: 10 smokers with symptoms of chronic bronchitis and chronic airflow limitation, six asymptomatic smokers with normal lung function, and nine nonsmoking control subjects. Peripheral airways were examined with histochemical methods to identify goblet cells and with immunohistochemical methods to identify total leukocytes (CD45(+) cells), neutrophils, macrophages, CD4(+) and CD8(+) cells in the epithelium. When compared with nonsmokers, smokers with both symptoms of chronic bronchitis and chronic airflow limitation had an increased number of goblet cells (p < 0.01), CD45(+) cells (p < 0. 01), macrophages (p < 0.05), and CD8(+) cells (p < 0.01) in the epithelium of peripheral airways. When all the smokers were grouped together, they showed an increased number of neutrophils (p < 0.05) along with an increased number of goblet cells, CD45(+) cells, macrophages and CD8(+) cells (p < 0.05) compared with nonsmokers. In conclusion, smokers with both symptoms of chronic bronchitis and chronic airflow limitation have an increased number of goblet cells and inflammatory cells in the epithelium of peripheral airways.

The distribution of neurokinin-1 and neurokinin-2 receptors in human central airways.

The precise locations of neurokinin (NK)-1 and NK-2 receptors in human airways, and their role in airway inflammatory diseases, have not been carefully examined. To determine the distribution of NK-1 and NK-2 receptors in human central airways, and to determine whether their distribution was different in smokers, we examined surgical specimens from patients undergoing lung resection for limited lung lesions. We mapped NK-1 and NK-2 receptors in four groups of subjects: four asymptomatic nonsmokers, seven asymptomatic smokers, seven symptomatic smokers with normal lung function, and eight symptomatic smokers with chronic airflow limitation. Tissues were immunostained with anti-NK-1- and anti-NK-2-receptor antibodies. Expression of NK-1 and NK-2 receptors was quantified through light microscopy and image analysis. Both NK-1 and NK-2 receptors were found in bronchial glands, bronchial vessels, and bronchial smooth muscle. Although no receptors were observed in the epithelium, receptors were occasionally found in nerves (NK-1) and in inflammatory cells (NK-2) such as T lymphocytes, macrophages, and mast cells. The distribution of both NK-1 and NK-2 receptors was similar in all the tissues examined in the four groups of subjects. These data show that NK-1 and NK-2 receptors are present in human central airways and that their expression is not modified by cigarette smoking.

CD8+ve cells in the lungs of smokers with chronic obstructive pulmonary disease.

Previous studies have shown an increased number of inflammatory cells and, in particular, CD8+ve cells in the airways of smokers with chronic obstructive pulmonary disease (COPD). In this study we investigated whether a similar inflammatory process is also present in the lungs, and particularly in lung parenchyma and pulmonary arteries. We examined surgical specimens from three groups of subjects undergoing lung resection for localized pulmonary lesions: nonsmokers (n = 8), asymptomatic smokers with normal lung function (n = 6), and smokers with COPD (n = 10). Alveolar walls and pulmonary arteries were examined with immunohistochemical methods to identify neutrophils, eosinophils, mast cells, macrophages, and CD4+ve and CD8+ve cells. Smokers with COPD had an increased number of CD8+ve cells in both lung parenchyma (p < 0.05) and pulmonary arteries (p < 0.001) as compared with nonsmokers. CD8+ve cells were also increased in pulmonary arteries of smokers with COPD as compared with smokers with normal lung function (p < 0.01). Other inflammatory cells were no different among the three groups. The number of CD8+ve cells in both lung parenchyma and pulmonary arteries was significantly correlated with the degree of airflow limitation in smokers. These results show that an inflammatory process similar to that present in the conducting airways is also present in lung parenchyma and pulmonary arteries of smokers with COPD.

CD8+ T-lymphocytes in peripheral airways of smokers with chronic obstructive pulmonary disease.

To investigate whether the inflammatory process in peripheral airways is different in smokers who develop symptoms of chronic bronchitis and chronic airflow limitation and in asymptomatic smokers who do not develop chronic airflow limitation, we examined surgical specimens obtained from 16 smokers undergoing lung resection for localized pulmonary lesions. Nine had symptoms of chronic bronchitis and chronic airflow limitation and seven were asymptomatic with normal lung function. In peripheral airways, immunohistochemical methods were performed to identify neutrophils, macrophages, CD4+ and CD8+ T-lymphocytes infiltrating the airway wall, and morphometric methods were used to measure the internal perimeter, the airway wall area, and the smooth muscle area. The number of CD8+ T-lymphocytes and the smooth muscle area were increased in smokers with symptoms of chronic bronchitis and chronic airflow limitation as compared with asymptomatic smokers with normal lung function, while the number of neutrophils, macrophages, and CD4+ T-lymphocytes were similar in the two groups of subjects examined. We concluded that smokers who develop symptoms of chronic bronchitis and chronic airflow limitation have an increased number of CD8+ T-lymphocytes and an increased smooth muscle area in the peripheral airways as compared with asymptomatic smokers with normal lung function, supporting the important role of CD8+ T-lymphocytes and airway remodeling in the pathogenesis of chronic obstructive pulmonary disease.

Inflammatory cells in the bronchial glands of smokers with chronic bronchitis.

To characterize the inflammatory process in the bronchial glands of smokers with chronic sputum production, we examined lobar bronchi from 18 subjects undergoing lung resection for localized pulmonary lesions, all with a history of cigarette smoking. Nine of the subjects had symptoms of chronic bronchitis and chronic airflow obstruction, and nine were asymptomatic, with normal lung function. The number of neutrophils, eosinophils, mast cells, macrophages, CD4+ and CD8+ T-lymphocytes, and the ratio of CD4+ to CD8+ cells were assessed in the bronchial glands, epithelium, and submucosa. Cells were identified through immunohistochemistry. Smokers with symptoms of chronic bronchitis had an increased number of neutrophils (p = 0.01) and macrophages (p = 0.03) and a decreased CD4+/CD8+ ratio (p = 0.01) in the bronchial glands as compared with asymptomatic smokers. Chronic bronchitic smokers also had an increased number of epithelial neutrophils (p = 0.04), whereas the numbers of macrophages and CD4+ and CD8+ T-lymphocytes in the epithelium and submucosa were similar in the two groups of smokers. No differences in numbers of eosinophils or mast cells were observed between bronchitic and asymptomatic smokers in any of the compartments examined. In conclusion, smokers with chronic sputum production have an increased infiltration of neutrophils and macrophages and an increased proportion of CD8+ T-lymphocytes in their bronchial glands, supporting the important role of bronchial-gland inflammation in the pathogenesis of chronic bronchitis.

Increased VIP-positive nerve fibers in the mucous glands of subjects with chronic bronchitis.

The presence and distribution of neuropeptide-containing nerves within bronchial surgical specimens has been investigated in bronchitic (n = 12) and in nonbronchitic subjects (n = 7). Lung tissue, obtained from patients undergoing thoracotomy for limited lung lesions, was processed immediately and analyzed for nerves using the streptavidin-biotin complex peroxidase method with antisera to the neural marker protein gene product 9.5 (PGP 9.5) and the neuropeptides vasoactive intestinal peptide (VIP), substance P (SP), calcitonin-gene related peptide (CGRP). There were no significant differences between the two groups with respect to the density of PGP 9.5-, SP-, or CGRP-positive nerves in both the locations assessed (smooth muscle layer and glands). The density of VIP-positive nerves was significantly higher in the glands of bronchitic than in nonbronchitic subjects. A negative relationship was found between the presence of airway inflammation, as indexed by mononuclear cell tissue infiltration, and the density of PGP 9.5-positive nerves in both smooth muscle and glands. Likewise, a relationship was found between the smoking history (packs/yr and age of onset of smoking) and the density of VIP-positive nerves in glands. These findings support a role for VIP in the hallmark of chronic bronchitis, i.e., sputum production.