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

Association of current smoking with airway inflammation in chronic obstructive pulmonary disease and asymptomatic smokers

BACKGROUND

Inflammation in the airways and lung parenchyma underlies fixed airway obstruction in chronic obstructive pulmonary disease. The exact role of smoking as promoting factor of inflammation in chronic obstructive pulmonary disease is not clear, partly because studies often do not distinguish between current and ex-smokers.

METHODS

We investigated airway inflammation in sputum and bronchial biopsies of 34 smokers with chronic obstructive pulmonary disease (9 Global initiative for Chronic Obstructive Lung Disease stage 0, 9 stage I, 10 stage II and 6 stage III) and 26 asymptomatic smokers, and its relationship with past and present smoking habits and airway obstruction.

RESULTS

Neutrophil percentage, interleukin-8 and eosinophilic-cationic-protein levels in sputum were higher in chronic obstructive pulmonary disease (stage I-III) than asymptomatic smokers. Inflammatory cell numbers in bronchial biopsies were similar in both groups. Current smoking correlated positively with macrophages: in bronchial biopsies in both groups, and in sputum in chronic obstructive pulmonary disease. Pack-years smoking correlated positively with biopsy macrophages only in chronic obstructive pulmonary disease.

CONCLUSION

Inflammatory effects of current smoking may mask the underlying ongoing inflammatory process pertinent to chronic obstructive pulmonary disease. This may have implications for future studies, which should avoid including mixed populations of smokers and ex-smokers.

Modelling COPD in mice

Chronic obstructive pulmonary disease (COPD) is characterised by persistent airflow limitation, neutrophilic inflammation, macrophage accumulation, and the production of cytokines, chemokines and proteases. Cigarette smoking is the major cause of COPD and there is currently no satisfactory therapy to help treat individuals with this disease. A better understanding of the cellular and molecular responses triggered by cigarette smoke may provide new molecular targets for the development of therapeutic agents. This brief review highlights some of the mouse models used to define the cellular, molecular and pathological consequences of cigarette smoke exposure.

NO2-induced airway inflammation is associated with progressive airflow limitation and development of emphysema-like lesions in C57BL/6 mice

The major features of chronic obstructive pulmonary disease (COPD) comprise a not fully reversible airflow limitation associated with an abnormal inflammatory response, increased mucus production and development of emphysema-like lesions. Animal models that closely mimic these alterations represent an important issue for the investigation of pathophysiological mechanisms. Since most animal models in this area have focused on specific aspects of the disease, we aimed to investigate whether exposure of C57BL/6 mice to nitrogen dioxide (NO2) may cause a more complex phenotype covering several of the characteristics of the human disease. Therefore, mice were exposed to NO2 for 14h each day for up to 25 days. Initial dose response experiments revealed the induction of a significant inflammatory response at a dose of 20 ppm NO2. Mice developed progressive airway inflammation together with a focal inflammation of the lung parenchyma characterized by a predominant influx of neutrophils and macrophages. In addition, goblet cell hyperplasia was detected in the central airways and increased collagen deposition was found in the lung parenchyma. NO2-exposed mice developed emphysema-like lesions as indicated by a significantly increased mean linear intercept as compared to control mice. Finally, the assessment of lung functional parameters revealed the development of progressive airway obstruction over time. In conclusion, our data provide evidence that the inflammatory response to NO2 exposure is associated with increased mucus production, development of airspace enlargement and progressive airway obstruction. Thus, NO2-exposed mice may serve as a model to investigate pathophysiological mechanisms that contribute to the development of human COPD.

αEβ7 Expression on CD8+ T-Cells in COPD BAL Fluid and on TGF-β Stimulated T-Cells In Vitro

The airway inflammation in patients with COPD shows increased numbers of CD8+ T-cells. Until now few studies have shown any functional data indicating a role for these cells in the pathogenesis of COPD. This paper focuses on a subset of CD8+ T-cells present in human lung, the intra-epithelial lymphocytes expressing the integrin alphaEbeta7, and their presence in bronchoalveolar lavage fluid from COPD patients. In this study we demonstrate that 64-89% of the CD8+ T-cells in bronchoalveolar lavage fluid from COPD patients are positive for CD103, the alpha subunit of alphaEbeta7. We also present an in vitro system in which it is possible to differentiate peripheral T-cells into a phenotype resembling the one found in bronchoalveolar lavage fluid, i.e., CD8+ CD103+. In this in vitro system we demonstrate that, in addition to TGF-beta1, cell-to-cell interaction between the T-cell and an antigen-presenting cell represented here by the monocyte, is crucial for a rapid, high and sustained expression of CD103. The signal provided by the monocytes is shown to be mediated through LFA-1 on the T-cell. Furthermore, differentiation of CD8+ T-cells by TGF-beta1 and monocytes results in down regulation of INF-gamma, TNF-alpha and GM-CSF production. IL-8 production is, however, retained in the alphaEbeta7 expressing cells. We see this work as an initiation on the quest for a functional characterization of one of the different types of CD8+ T cells present in COPD. In the longer perspective we hope this can lead to an increased understanding of how these cells can contribute to the disease pathology.

Differences in airway remodeling between asthma and chronic obstructive pulmonary disease

The functional consequence of asthma and chronic obstructive pulmonary disease (COPD)is airflow limitation, which is mostly reversible in asthma and not fully reversible in COPD. In both diseases, inflammatory conditions are associated with cellular and structural changes,referred to as remodeling, and these structural changes may lead to thickening of the airway wall, thereby promoting airway narrowing and airflow limitation. However, the pattern of infiltrated cells and the pattern of structural changes occur differently in the two diseases. In asthma, CD4+, T lymphocytes, eosinophils, and mast cells are the predominant cells involved,whereas in COPD, CD8+, T lymphocytes, and macrophages are predominantly involved. In severe cases of asthma and COPD, neutrophil infiltration becomes evident. Regarding structural changes, epithelial injury and early thickening of reticular basement membrane are highly characteristic of the airway wall of asthmatics. Increases in airway smooth muscle mass occur in large airways of severe asthmatics and in small airways of patients with COPD. Thickening of the airway wall, goblet cell hyperplasia, mucous gland hypertrophy, and the luminal obstruction caused by inflammatory exudates and mucous are features of both asthma and COPD. Squamous epithelial metaplasia and airway wall fibrosis are commonly observed characteristics of COPD. Destruction and fibrosis of the alveolar wall occur in COPD but not in asthma. The remodeling processes accompanied by chronic inflammatory infiltrates interact in a complex fashion and contribute to the development of airflow limitation in both asthma and COPD.

Flow cytometric characterization of cell populations in bronchoalveolar lavage and bronchial brushings from patients with chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a serious, chronic inflammatory disease of the airway associated with cigarette smoking. Leucocytes are involved in the inflammatory process in the airways in COPD. There is a need for accurate characterization of cellular populations in bronchoalveolar lavage (BAL) due to variation in the predominant cell types reported, which were investigated mostly with manual counting techniques.

METHODS

Bronchial brushings and BAL were obtained from human subjects undergoing fiber optic bronchoscopy. Flow cytometry was applied to identify various cell types. Quenching of autofluorescence of BAL-derived alveolar macrophages was achieved with eta-octyl beta-D-galactopyranoside and crystal violet. Comparisons of cell counts obtained with flow cytometric and manual counting methods were performed.

RESULTS

Correlation analysis showed that manual cell counting methods overestimated the percentage of macrophages when compared with flow cytometric methods (R2 = 0.54). There was also a small tendency by manual counting to underestimate the percentage of lymphocytes and neutrophils. Using flow cytometry, the percentage and absolute numbers of alveolar macrophages and lymphocytes in BAL were not significantly different between patients with COPD and control subjects. The percentage and absolute numbers of neutrophils were higher in BAL from patients with moderate to severe COPD.

CONCLUSIONS

This novel flow cytometric assay for identification of various cell types from heterogenous samples of BAL and bronchial brushing will allow further investigation of cell characteristics, such as cytokine production and receptor expression, and an accurate evaluation of apoptosis for different cell types and provide a rationale for urgently required effective treatments for COPD.

Attenuation of tobacco smoke-induced lung inflammation by treatment with a soluble epoxide hydrolase inhibitor

Changes in the lungs due to smoking include inflammation, epithelial damage, and remodeling of the airways. Airway inflammation is likely to play a critical role in the genesis and progression of tobacco smoke-induced airway disease. Soluble epoxide hydrolase (sEH) is involved in the metabolism of endogenous chemical mediators that play an important role in inflammation. Epoxyeicosatrienoic acids (EETs) have demonstrated antiinflammatory properties, and hydrolysis of these epoxides by sEH is known to diminish this activity. To examine whether acute tobacco smoke-induced inflammation could be reduced by a sEH inhibitor, 12-(3-adamantane-1-yl-ureido)-dodecanoic acid n-butyl ester was given by daily s.c. injection to spontaneously hypertensive rats exposed to filtered air or tobacco smoke for a period of 3 days (6 h/day). Acute exposure to tobacco smoke significantly increased by 3.2-fold (P <0.05) the number of cells recovered by bronchoalveolar lavage. The sEH inhibitor significantly decreased total bronchoalveolar lavage cell number by 37% in tobacco smoke-exposed rats with significant reductions noted in neutrophils, alveolar macrophages, and lymphocytes. A combination of sEH inhibitor and EETs was more significant in its ability to further reduce tobacco smoke-induced inflammation compared with the sEH inhibitor alone. The sEH inhibitor led to a shift in some plasma epoxides and diols that are consistent with the hypothetical action of these compounds. We conclude that an sEH inhibitor, in the presence or absence of EETs, can attenuate, in part, inflammation associated with acute exposure to tobacco smoke.

Phosphodiesterase 4-selective inhibition: novel therapy for the inflammation of COPD

Chronic obstructive pulmonary disease (COPD), which is increasing in prevalence and a leading cause of death worldwide, is characterised by an 'abnormal' inflammatory response. There is a predominance of CD8(+) T cells, CD68(+) macrophages and, in exacerbations-neutrophils, in both conducting airways and lung parenchyma. Smoking is the most common etiological factor leading to COPD and smoking cessation is the most effective approach to the management of COPD, but it does not resolve the underlying inflammation of COPD, which persists, even in ex-smokers. The presence of mucosal inflammation serves as the rationale for anti-inflammatory therapy. However, while there are reductions in the numbers of mast cells following treatment with inhaled steroids, CD8(+), CD68(+) cells and neutrophils are refractory to such treatment, highlighting a need for additional, more targeted interventions. Phosphodiesterase 4 (PDE4) inhibitors are a promising and novel drug class that have potent activity against several key components of the inflammatory process in COPD. A recently published study has shown that the selective PDE4 inhibitor, cilomilast, reduces the numbers of bronchial mucosal CD8(+) and CD68(+) cells and neutrophils. This review focuses on the nature of the inflammation in COPD and considers how selective PDE4 inhibitors may optimize and advance our treatment of this chronic condition.

Increased activity of matrix metalloproteinase-8 and matrix metalloproteinase-9 in induced sputum from patients with COPD

BACKGROUND

The increased expression of matrix metalloproteinases (MMPs) is considered to be a key factor in the development of COPD. Net MMP activity represents a tightly regulated process, which is not addressed by conventional investigation methods such as messenger RNA or protein expression. Yet, quantitative data on MMP activity in the airways of COPD patients are lacking.

METHODS

We used specific immunocapture assays to quantify the activity of MMP collagenase (ie, MMP-1, MMP-8, and MMP-13) and MMP gelatinase (ie, MMP-2 and MMP-9) in the induced sputum of COPD patients (17 patients; FEV(1), 56% predicted) and healthy smokers (17 subjects; FEV(1), 99% predicted).

RESULTS

Levels of total and active MMP-8 and MMP-9 were significantly increased in COPD patients vs control subjects, whereas MMP-1 activity levels were similar in both groups. The activity of MMP-2 and MMP-13 remained below the detection threshold of the assays. MMP-8 and MMP-9 activity were strongly related to neutrophilia in both groups, and the results of immunohistochemistry tests on sputum cytospins showed that MMP-9 was expressed in both alveolar macrophages and neutrophils, whereas MMP-8 expression was exclusively observed in neutrophils. A positive correlation was found between sputum MMP-8 and MMP-9 activity and the degree of airflow limitation.

CONCLUSION

We demonstrate increased MMP-8 and MMP-9 activity in the airway compartment of patients with mild-to-moderate COPD. This study provides further evidence of an impaired proteinase-antiproteinase balance in COPD patients.

The role of airway smooth muscle in the pathogenesis of airway wall remodeling in chronic obstructive pulmonary disease

Airway wall remodeling processes are present in the small airways of patients with chronic obstructive pulmonary disease, consisting of tissue repair and epithelial metaplasia that contribute to airway wall thickening and airflow obstruction. With increasing disease severity, there is also increased mucous metaplasia and submucosal gland hypertrophy, peribronchial fibrosis, and an increase in airway smooth muscle mass. Apart from its contractile properties, airway smooth muscle produces inflammatory cytokines, proteases, and growth factors, which may contribute to the remodeling process and induce phenotypic changes of the muscle. Airflow limitation responds minimally to beta-agonists and corticosteroid therapy, unlike asthma, perhaps because of alterations in beta-receptor or glucocorticoid receptor numbers, alterations in receptor signaling, or the constrictive limitation imposed by peribronchial fibrosis. Better response is observed with the combination of inhaled long-acting beta-agonists and corticosteroids. This could result from effects at the level of airway smooth muscle. Airway wall remodeling may involve the release of growth factors from inflammatory or resident cells. The influence of smoking cessation or of current therapies on airway wall remodeling is unknown. Specific therapies for airway wall remodeling may be necessary, together with noninvasive methods of imaging small airway wall remodeling to assess responses.

Inhaled Corticosteroids in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a serious illness that affects over 5% of the adult population. It is one of the few conditions for which the mortality and morbidity are still increasing. Experts expect COPD to become the third leading cause of death and the fifth leading cause of disability worldwide by the year 2020. Thus far, the only treatments that have been shown to make a difference to survival are smoking cessation and the use of oxygen supplements for those who are hypoxaemic at rest. The use of inhaled corticosteroids as monotherapy or in combination with a long-acting beta2-adrenoceptor agonist for COPD is controversial. Experimental data indicate that the inflammatory process in COPD may be resistant to the anti-inflammatory effects of corticosteroids. However, several large clinical studies have shown that inhaled corticosteroids in relatively high doses (e.g. budesonide 800 microg/day or fluticasone propionate 1 mg/day) reduce exacerbations by 20-30% and improve the health status of COPD patients by a similar amount compared with placebo. Withdrawal of inhaled corticosteroids may increase clinical exacerbation rates by 50% in COPD patients and by 2-fold in those with severe disease. Combined therapy with inhaled corticosteroids and long-acting beta2-adrenoceptor agonists may be superior to individual component therapy in reducing exacerbations. However, these medications must be used cautiously, as they have been associated with certain adverse effects. Inhaled corticosteroids, for instance, increase the risk for dysphonia and oral thrush by 2- to 3-fold. Skin bruising is also more common in users than in non-users of inhaled corticosteroids. On balance, for those with moderate-to-severe COPD and those who experience frequent exacerbations, judicious use of inhaled corticosteroids alone or in combination with long-acting beta2-adrenoceptor agonists appears reasonable.

Cellular and molecular mechanisms in chronic obstructive pulmonary disease: an overview

In the last decade, the analysis of bronchial biopsies and lung parenchyma obtained from chronic obstructive pulmonary disease (COPD) patients compared with those from smokers with normal lung function and non-smokers has provided new insights on the role of the different inflammatory and structural cells, their signalling pathways and mediators, contributing to a better knowledge of the pathogenesis of COPD. This review summarizes and discusses the lung pathology of COPD patients with emphasis on inflammatory cell phenotypes that predominate in different clinical conditions. In bronchial biopsies, a cascade of events takes place during progression from mild-to-severe disease. T lymphocytes, particularly CD8+ cells and macrophages are the prevalent inflammatory cells in the lung of healthy smokers and patients with mild COPD, while total and activated neutrophils predominate in severe COPD. The number of CD4+, CD8+ cells and macrophages expressing nuclear factor-kappa B (NF-kappaB), STAT-4 and IFN-gamma proteins as well as endothelial adhesion molecule-1 in endothelium is increased in mild/moderate disease. In contrast, activated neutrophils (MPO+ cells) and increased nitrotyrosine immunoreactivity develops in severe COPD. In bronchial biopsies obtained during COPD exacerbations, some studies have shown an increased T cell and granulocyte infiltration. Regular treatment with high doses of inhaled glucocorticoids does not significantly change the number of inflammatory cells in bronchial biopsies from patients with moderate COPD. The profile in lung parenchyma is similar to bronchial biopsies. 'Healthy' smokers and mild/moderate diseased patients show increased T lymphocyte infiltration in the peripheral airways. Pulmonary emphysema is associated with a general increase of inflammatory cells in the alveolar septa. The molecular mechanisms driving the lymphocyte and neutrophilic prevalence in mild and severe disease, respectively, needs to be extensively studied. Up-regulation of pro-inflammatory transcription factors NF-kappaB and STAT-4 in mild, activated epithelial and endothelial cells in the more severe disease may contribute to this differential prevalence of infiltrating cells.

Changes in sputum T-lymphocyte subpopulations at the onset of severe exacerbations of chronic obstructive pulmonary disease

CD8+ve T-cell responses play a primary role in chronic obstructive pulmonary disease (COPD), but there is little information regarding COPD exacerbations. Sputum induction is a relatively non-invasive and safe method to study airway inflammation. The aim of the study was to investigate changes in airway T-lymphocyte subpopulations at the onset of severe COPD exacerbations via analysis of sputum. Induced sputum samples were collected from 12 COPD patients aged (mean+/-sd) 69+/-7 years, ex-smokers (68+/-23 pack-years), mean FEV1 (%predicted) 40+/-14 at the onset of an acute severe exacerbation requiring hospital admission and 16 weeks after remission of the exacerbation. Inflammatory cells and T-lymphocyte subpopulations (CD4, CD8, Tc1, Tc2) were measured using chemical and double immunocytochemical methods. Increased percentages of sputum neutrophils (P=0.002) and decreased CD4/CD8 and CD8-IFNgamma/CD8-IL4+ve (Tc1/Tc2) cell ratios (P=0.03, P=0.02, respectively) were found at the onset of exacerbation compared to stable state. We conclude that a CD8+ve type-2-mediated immune response is induced at the onset of severe COPD exacerbation.

Models of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major global health problem and is predicted to become the third most common cause of death by 2020. Apart from the important preventive steps of smoking cessation, there are no other specific treatments for COPD that are as effective in reversing the condition, and therefore there is a need to understand the pathophysiological mechanisms that could lead to new therapeutic strategies. The development of experimental models will help to dissect these mechanisms at the cellular and molecular level. COPD is a disease characterized by progressive airflow obstruction of the peripheral airways, associated with lung inflammation, emphysema and mucus hypersecretion. Different approaches to mimic COPD have been developed but are limited in comparison to models of allergic asthma. COPD models usually do not mimic the major features of human COPD and are commonly based on the induction of COPD-like lesions in the lungs and airways using noxious inhalants such as tobacco smoke, nitrogen dioxide, or sulfur dioxide. Depending on the duration and intensity of exposure, these noxious stimuli induce signs of chronic inflammation and airway remodelling. Emphysema can be achieved by combining such exposure with instillation of tissue-degrading enzymes. Other approaches are based on genetically-targeted mice which develop COPD-like lesions with emphysema, and such mice provide deep insights into pathophysiological mechanisms. Future approaches should aim to mimic irreversible airflow obstruction, associated with cough and sputum production, with the possibility of inducing exacerbations.

Increased IgE-antibodies to Staphylococcus aureus enterotoxins in patients with COPD

Recent evidence suggests that Staphylococcus aureus enterotoxins (SAEs) could modify airway disease by acting as superantigens, an immune response that can be monitored by detection of IgE antibodies to SAEs. We studied the expression of total IgE and specific IgE to SAEs using the Uni-CAP system in healthy controls, smokers without COPD and COPD patients. Only 1/10 controls (10%) and 1/16 smokers (6.3%) had IgE to SAEs compared to 7/18 patients with stable COPD (38.9%) and 21/54 patients with exacerbated COPD (38.9%). The IgE levels to SAEs of the patients with stable COPD (0.18 [0.05-26.2]kUA/l) and the patients with exacerbated COPD (0.09 [0.05-18.6]kUA/l) were significantly higher than those of smokers (n = 16; 0.05 [0.05-0.82]kUA/l) and controls (n = 11; 0.05 [0.05 0.9]kUA/l, P<0.05). IgE to SAEs decreased significantly in the exacerbated patients during hospitalization (0.13 [0.05-18.3] vs. 0.05 [0.05-11]kUA/l, P<0.001) going along with a significant increase in FEV1 (38.1 [16.9-79.5] vs. 51.6 [15-80]%predicted, P<0.001). Similarly to severe asthma, we found significantly elevated IgE to SAE in COPD patients. Our data for the first time suggest differences between healthy subjects, smokers and patients with established COPD regarding the role of bacterial products and point to a possible disease modifying role of SAEs.

The relationship between asthma and COPD. Lessons from transgenic mice

Asthma is characterized by eosinophilic and mononuclear cell infiltration, mucous metaplasia, airway remodeling, reversible airflow obstruction, and airway hyperresponsiveness. COPD is typified by nonreversible or incompletely reversible airway obstruction, often accompanied by mucous metaplasia and alveolar destruction. There is considerable overlap in pathogenesis and clinical features between the conditions. However, asthma and COPD may be distinguished by their respective cytokine profiles. Studies in transgenic mice have illuminated the roles of the T helper (Th) 1-mediated cytokine interferon-gamma in COPD, supporting the British hypothesis, and the Th2-mediated cytokine interleukin-13 in asthma, supporting the Dutch hypothesis. COPD and asthma may represent disease states along a continuum, with varying degrees of each disease often present in the same patient.

Impact of tobacco smoke on interleukin-16 protein in human airways, lymphoid tissue and T lymphocytes

CD4(+) and CD8(+) lymphocytes are mobilized in severe chronic obstructive pulmonary disease (COPD) and the CD8(+) cytokine interleukin (IL)-16 is believed to be important in regulating the recruitment and activity of CD4(+) lymphocytes. In the current study, we examined whether tobacco smoke exerts an impact not only on IL-16 in the lower airways but also in CD4(+) or CD8(+) lymphocytes or in lymphoid tissue. The concentration of IL-16 protein was measured by enzyme-linked immunosorbent assay (ELISA) in concentrated bronchoalveolar lavage fluid (BALF) collected from 33 smokers with chronic bronchitis (CB), eight asymptomatic smokers (AS) and seven healthy never-smokers (NS). The concentrations of IL-16 and soluble IL-2 receptor alpha (sIL-2Ralpha) protein were also measured in conditioned medium from human blood CD4(+) and CD8(+) lymphocytes stimulated with tobacco smoke extract (TSE) in vitro. IL-16 mRNA was assessed in vitro as well, using reverse transcription-polymerase chain reaction (RT-PCR). Finally, the intracellular immunoreactivity for IL-16 protein (IL-16IR) was assessed in six matched pairs of palatine tonsils from smokers and non-smokers. BALF IL-16 was higher in CB and AS than in NS. TSE substantially increased the concentration of IL-16 but not sIL-2Ralpha in conditioned medium from CD4(+) and CD8(+) lymphocytes. There was no corresponding effect on IL-16 mRNA. IL-16IR in tonsils was lower in smokers than in non-smokers. The current findings demonstrate that tobacco smoke exerts a wide impact on the CD8(+) cytokine IL-16, in the airway lumen, in blood CD4(+) and CD8(+) lymphocytes and in lymphoid tissue. The effect on IL-16 release may be selective for preformed IL-16 in CD4(+) lymphocytes. New clinical studies are required to evaluate whether tobacco smoke mobilizes T lymphocytes via IL-16 in the lower airways and whether this mechanism can be targeted in COPD.

An immune basis for lung parenchymal destruction in chronic obstructive pulmonary disease and emphysema

BACKGROUND

Chronic obstructive pulmonary disease and emphysema are a frequent result of long-term smoking, but the exact mechanisms, specifically which types of cells are associated with the lung destruction, are unclear.

METHODS AND FINDINGS

We studied different subsets of lymphocytes taken from portions of human lungs removed surgically to find out which lymphocytes were the most frequent, which cell-surface markers these lymphocytes expressed, and whether the lymphocytes secreted any specific factors that could be associated with disease. We found that loss of lung function in patients with chronic obstructive pulmonary disease and emphysema was associated with a high percentage of CD4+ and CD8+ T lymphocytes that expressed chemokine receptors CCR5 and CXCR3 (both markers of T helper 1 cells), but not CCR3 or CCR4 (markers of T helper 2 cells). Lung lymphocytes in patients with chronic obstructive pulmonary disease and emphysema secrete more interferon gamma--often associated with T helper 1 cells--and interferon-inducible protein 10 and monokine induced by interferon, both of which bind to CXCR3 and are involved in attracting T helper 1 cells. In response to interferon-inducible protein 10 and monokine induced by interferon, but not interferon gamma, lung macrophages secreted macrophage metalloelastase (matrix metalloproteinase-12), a potent elastin-degrading enzyme that causes tissue destruction and which has been linked to emphysema.

CONCLUSIONS

These data suggest that Th1 lymphoctytes in the lungs of people with smoking-related damage drive progression of emphysema through CXCR3 ligands, interferon-inducible protein 10, and monokine induced by interferon.

Can endobronchial biopsy analysis be recommended to discriminate between asthma and COPD in routine practice?

BACKGROUND

International guidelines stress the importance of accurately discriminating between asthma and chronic obstructive pulmonary disease (COPD). Although characteristic pathological features have been described for both conditions, their discriminatory power has never been systematically assessed.

METHODS

Endobronchial biopsy (EBB) specimens from patients with a clear clinical diagnosis of asthma and COPD (50 per group) were examined by three pathologists in a double blind manner. They were asked to propose a pathological diagnosis of either asthma or COPD and to analyse qualitatively the most frequent abnormalities reported in the literature.

RESULTS

The sensitivity and specificity of EBB ranged from 36% to 48% and from 56% to 79%, respectively. Eosinophils strongly biased the pathological diagnoses in favour of asthma, whereas their estimated prevalence was similar (11-37% in asthma and 13-41% in COPD). Metaplasia (11-39% in COPD, 1-18% in asthma) and epithelial inflammation (28-61% in COPD, 11-38% in asthma) tended to be specific to COPD, whereas epithelial desquamation (80-98% in asthma, 61-88% in COPD) and basement membrane thickening (71-94% in asthma, 53-88% in COPD) tended to be associated with asthma. There was acceptable intra- and inter-observer agreement only for metaplasia and epithelial eosinophils.

CONCLUSIONS

Specific histopathological features of asthma and COPD probably exist, but current routine analysis procedures to assess EBB specimens are not sufficiently discriminatory. This might be rectified by improving pathological definitions.

Abnormal alveolar attachments with decreased elastic fiber content in distal lung in fatal asthma

Small airway disease is thought to contribute significantly to functional impairment caused by asthma. Functional evidence of airway-parenchyma uncoupling in asthma, such as loss of deep breath bronchodilator effect in bronchoconstrictive episodes and enhanced airway closure, has been previously demonstrated. Elastic fibers are essential to maintain adequate elastic recoil of the lungs. In this study, we hypothesized that alveolar attachments could be abnormal and that elastic fibers could be damaged in the distal lungs of patients with fatal asthma. For this purpose, we measured the number of abnormal alveolar attachments and quantified the content of elastic fibers in the adventitial layer of small airways and in the peribronchial and distal alveolar septa of 15 patients who died of asthma (FA) and 9 control subjects (CTRL). Our data (geometric mean [range]) showed an increased proportion of abnormal alveolar attachments per centimeter of basement membrane perimeter in fatal asthma (FA, 0.18 [0.03-4.00]; CTRL, 0.00 [0.00-0.12]; p < 0.001) and decreased elastic fiber content in the small airway adventitial layer (FA, 4.08 [2.22-11.46] microm; CTRL, 6.79 [5.62-10.0] microm; p = 0.01) and in the peribronchial alveoli (FA, 1.08 [0.46-1.91] microm; CTRL, 1.81 [1.22-1.74] microm; p = 0.003), but not in the distal alveoli. We propose that structural alterations at the peribronchiolar level might contribute to the pathogenesis of some functional abnormalities observed in patients with severe asthma.

Mechanisms of chronic airway obstruction in smokers

Studies over the past few decades have showed a clear association between cigarette smoking and the development of chronic airway obstruction. Yet, only a minority of smokers is affected so that in many, even heavy, smokers, pulmonary function remains within normal limits. While carcinogens have been well characterized, there is only limited information about the constituents of cigarette smoke responsible for inducing chronic airway obstruction. In addition, the associated risks factors for airway obstruction in smokers have not been totally identified. The present paper is a review of the recently accumulated facts concerning the intimate action of cigarette smoke at the level of large and small airways and lung parenchyma. The role of classical inflammatory cells such as neutrophils and alveolar macrophages is reviewed, but emphasis is put on recent evidence indicating the involvement of CD8 + T-lymphocytes and possibly eosinophils in the genesis of the structural changes leading to airways obstruction. The mechanisms by which airway inflammation and remodelling cause airway narrowing and airflow limitation are discussed, along with the associated loss of lung elasticity secondary to destructive emphysema. Other biological, epidemiological, physiopathological, and clinical aspects are analyzed, stressing such fundamental aspects as the defence mechanisms, the morpho-functional correlations, the identification of susceptible smokers, and the early detection of airway obstruction, both in specialized laboratories and in primary care.

Noninvasive assessment of airway alterations in smokers: the small airways revisited

It has been shown that structural changes in small airways of smokers with average smoking histories greater than 35 pack-years could be reflected in the single-breath washout test. The more sophisticated multiple breath washout test (MBW) has the potential to anatomically locate the affected small airways in acinar and conductive lung zones through increased phase III slope indices S(acin) and S(cond), respectively. Pulmonary function, S(acin), and S(cond) were obtained in 63 normal never-smokers and in 169 smokers classified according to smoking history (< 10 pack-years; 10-20 pack-years; 20-30 pack-years; > 30 pack-years). Compared with never-smokers, significant changes in S(acin) (p = 0.02), S(cond) (p < 0.001), and diffusing capacity (DL(CO); p < 0.001) were detected from greater than 10 pack-years onwards. Spirometric abnormality was significant only from greater than 20 pack-years onwards. In smokers with greater than 30 pack-years and DL(CO) less than 60% predicted, the presence of emphysema resulted in disproportionally larger S(acin) than S(cond) increases. We conclude that S(cond) and S(acin) can noninvasively detect airway changes from as early as 10 pack-years onwards, locating the earliest manifestations of smoking-induced small airways alterations around the acinar entrance. In these early stages, the associated DL(CO) decrease may be a reflection of ventilation heterogeneity rather than true parenchymal destruction. In more advanced stages of smoking-induced lung disease, differential patterns of S(acin) and S(cond) are characteristic of the presence of parenchymal destruction in addition to peripheral airways alterations.

Inflammatory features of nasal mucosa in smokers with and without COPD

BACKGROUND

To investigate whether nasal and bronchial inflammation coexists in chronic obstructive pulmonary disease (COPD), nasal and bronchial biopsy specimens from seven control subjects, seven smokers without COPD, and 14 smokers with COPD were studied.

METHODS

Nasal and bronchial biopsy specimens were taken from the same patients during bronchoscopy and squamous cell metaplasia and the thickness of the epithelium and basement membrane were measured. The numbers of eosinophils (EG2), neutrophils (elastase), macrophages (CD68), and CD8 T lymphocytes (CD8/144B) were assessed by immunohistochemistry.

RESULTS

Smokers with and without COPD had squamous metaplasia in the nasal and bronchial epithelium. In all groups the thickness of the nasal epithelium was greater than that of the bronchial epithelium. The thickness of the basement membrane was similar in nasal and bronchial biopsy specimens from smokers with and without COPD, but was greater in the bronchi than in the nasal epithelium of controls. Eosinophil number was higher in the nasal and bronchial mucosa of smokers without COPD than in smokers with COPD or controls. Neutrophil number was higher in the nasal and bronchial mucosa of smokers with COPD than in smokers without COPD or controls. CD8 T lymphocyte numbers were similar in smokers with and without COPD and higher than in controls. There were fewer macrophages in nasal and bronchial biopsy specimens from smokers without COPD than in those with COPD.

CONCLUSION

Nasal and bronchial inflammation coexists in smokers and is characterised by infiltration of CD8 T lymphocytes. In smokers without COPD this feature is associated with an increased number of eosinophils, while in those with COPD it is linked to an increased number of neutrophils in both nasal and bronchial biopsy specimens.

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.

Macrophage phagocytosis of apoptotic neutrophils is compromised by matrix proteins modified by cigarette smoke and lipid peroxidation products

Clearance of apoptotic cells by phagocytosis plays an important role in the resolution of an inflammatory response. Macrophages interacting with extracellular matrix (ECM) proteins upregulate their phagocytic capacity. Cigarette smoke contains highly reactive carbonyls that modify proteins which directly/indirectly affects cellular function. We observed, in vitro, that human macrophages interacting with carbonyl or cigarette smoke modified ECM proteins dramatically down regulated their ability to phagocytose apoptotic neutrophils. We also show that this interaction with carbonyl-adduct modified ECM proteins led to increased macrophage adhesion in vitro. We hypothesise that changes in the ECM environment as a result of cigarette smoking affect the ability of macrophages to remove apoptotic cells. Moreover, we postulate that this decreased phagocytic activity was as a result of sequestration of receptors involved in the uptake of apoptotic cells towards that of recognition of carbonyl adducts on the modified ECM proteins leading to increased macrophage adhesion.

Activation of Bronchial Epithelial Cells in Smokers Without Airway Obstruction and Patients With COPD

STUDY OBJECTIVE

The aim of this study was to investigate the basal level as well as the tumor necrosis factor (TNF)-alpha- and interferon (IFN)-gamma-induced expression and release of the neutrophil chemoattractants interleukin (IL)-8 and growth-related oncogene (GRO)-alpha in primary bronchial epithelial cells (PBECs) from smokers without airflow obstruction and patients with COPD. In addition, the expression of both TNF-alpha-receptor subtypes--p55 TNF-receptor subtype (TNF-R55) and p75 TNF-receptor subtype (TNF-R75)--was quantified in PBECs.

DESIGN

PBECs from eight smokers without airflow limitation and eight patients with COPD were stimulated with 50 ng/mL of TNF and 200 U/mL of IFN-gamma for 4 h along with unstimulated time controls. The transcriptional expression and protein release were quantitatively assessed by means of real-time polymerase chain reaction and enzyme-linked immunosorbent assay.

RESULTS

Basal level messenger RNA (mRNA) expression and protein release of IL-8 and GRO-alpha were not significantly different between both groups, although a trend toward higher IL-8 levels was seen in patients with COPD. TNF-alpha induced significantly higher mRNA amounts of IL-8 (p = 0.005) and GRO-alpha (p = 0.007) in patients with COPD. This was accompanied by higher protein release data for IL-8 (p = 0.005) and GRO-alpha (p = 0.007). IFN-gamma had no significant effect on the mRNA expression and protein release of IL-8 and GRO-alpha in either group. TNF-R55 and TNF-R75 were detectable in PBECs. However, no significant differences were found between both groups with respect to steady-state mRNA levels of TNF-alpha-receptor subtypes.

CONCLUSION

PBECs from patients with COPD show significantly higher TNF-alpha-induced release of the neutrophil chemoattractant CXC-chemokines IL-8 and GRO-alpha compared to smokers without airflow limitation. This increased activation of PBECs may contribute to the predominance of neutrophils seen in the airway lumen of patients with COPD.

Lymphoid tissue and emphysema in the lungs of transgenic mice inducibly expressing tumor necrosis factor-alpha

To develop a model in which the pathogenic effects of the proinflammatory cytokine tumor necrosis factor-alpha (TNF) could be investigated, transgenic mice that express TNF in the lung under the control of a doxycycline-inducible promoter were generated. TNF transgene message was expressed at a low level in the absence of doxycycline treatment and was induced in the lung by administration of the drug. Analysis of lung lavage fluid indicated increases in neutrophils and lymphocytes in doxycycline-treated transgenic mice. Histologic analysis of lungs from adult transgenic mice treated with doxycycline revealed prominent development of lymphoid tissue and increases in airspace size. Genes upregulated in TNF transgenic mice, as identified by oligonucleotide microarray analysis, included a variety of transcripts expressed in lymphoid tissues. Immunohistochemical analysis demonstrated the presence of B lymphocytes and, to a lesser extent, T lymphocytes within lymphoid aggregates in TNF transgenic mice. CD8-positive T cells were absent from lymphocytic nodules, but in the lung parenchyma were more abundant in transgenic than in nontransgenic mice. These results indicate that induction of TNF in adult lung promotes the formation of lymphoid tissue and emphysema, and provides a model in which the pathogenic effects of TNF on the lung can be investigated.

Transforming growth factor-beta1 genotype and susceptibility to chronic obstructive pulmonary disease

BACKGROUND

Only a few long term smokers develop symptomatic chronic obstructive pulmonary disease (COPD) and this may be due, at least in part, to genetic susceptibility to the disease. Transforming growth factor beta1 (TGF-beta1) has a number of actions that make it a candidate for a role in the pathogenesis of COPD. We have investigated a single nucleotide polymorphism at exon 1 nucleotide position 29 (T-->C) of the TGF-beta1 gene that produces a substitution at codon 10 (Leu-->Pro).

METHODS

The frequency of this polymorphism was determined in 165 subjects with COPD, 140 healthy blood donors, and 76 smokers with normal lung function (resistant smokers) using the polymerase chain reaction and restriction enzyme fragment length polymorphism.

RESULTS

The distribution of genotypes was Leu-Leu (41.8%), Leu-Pro (50.3%), and Pro-Pro (7.9%) for subjects with COPD, which was significantly different from the control subjects (blood donors: Leu-Leu (29.3%), Leu-Pro (52.1%) and Pro-Pro (18.6%), p=0.006; resistant smokers: Leu-Leu (28.9%), Leu-Pro (51.3%) and Pro-Pro (19.7%), p=0.02). The Pro10 allele was less common in subjects with COPD (33%) than in blood donors (45%; OR=0.62, 95% CI 0.45 to 0.86, p=0.005) and resistant smokers (45%; OR=0.59, 95% CI 0.40 to 0.88, p=0.01).

CONCLUSIONS

The proline allele at codon 10 of the TGF-beta1 gene occurs more commonly in control subjects than in individuals with COPD. This allele is associated with increased production of TGF-beta1 which raises the possibility that TGF-beta1 has a protective role in COPD.

Determinants of BMI in patients with COPD

OBJECTIVE

COPD is characterized by significant chronic inflammation that is evident not only in the pulmonary compartment but also in the circulation. Peripheral blood features of COPD include markers of oxidative stress and altered circulating levels of inflammatory mediators and acute-phase proteins. The presence of a systemic inflammatory response may influence quality of life by giving rise to weight loss, muscle wasting and tissue depletion. The aim of the present study was to evaluate the determinants of body mass and the value of serum tumour necrosis factor alpha (TNF-alpha) as a marker of weight loss in COPD patients, and to correlate this with the burden of oxidative stress as measured by serum malonyldialdehyde (MDA) levels.

METHODOLOGY

Fifty-two male COPD patients (mean age 62.55 +/- 6.81 years) were studied. After anthropometric measurements and standard spirometry, serum TNF-alpha concentration was measured by enzyme-linked immunosorbent assay using an hTNF-alpha kit, and MDA was studied spectrophotometrically using the Yoshioka-Kawada method.

RESULTS

The mean BMI was 24.82 +/- 3.46. BMI was lower than normal (< 19) in six patients. Mean serum TNF-alpha concentration was 14.99 +/- 8.98 pg/mL and MDA was 0.93 +/- 0.13 nmol/L. There was no significant correlation between serum MDA and TNF concentrations (P = 0.140). Serum TNF-alpha and MDA concentrations were not correlated with severity of airflow obstruction or degree of hypoxaemia (P > 0.05 for all). BMI was negatively correlated with burden of smoking (pack-years) (r = -0.392, P= 0.004); but not with pulmonary function, degree of hypoxaemia, serum TNF-alpha or MDA levels. BMI was significantly lower in current smokers than ex-smokers (P = 0.041); however, serum MDA and TNF levels were similar in both groups.

CONCLUSION

The results of this study indicate that body mass is related to smoking status (both pack-years and continuance of smoking) in COPD; however, serum TNF-alpha concentration does not seem to be a good marker of weight loss in these patients.

Perforin expression and cytotoxic activity of sputum CD8+ lymphocytes in patients with COPD

BACKGROUND

Previous studies have shown that the inflammatory response to cigarette smoking differs between smokers who acquire COPD and those who do not, and the CD8(+) T- lymphocytes have been identified as a key player in this response.

OBJECTIVE

To investigate the cytotoxic activity and perforin expression of CD8(+) lymphocytes in the airway lumen of patients with COPD.

METHODS

Thirty-six male smokers with COPD, 25 male smokers without COPD, and 10 healthy nonsmokers participated in the study. T-lymphocytes of induced sputum samples were labeled with appropriate monoclonal antibodies and measured using flow cytometry. The cytotoxic activity of CD8(+) cells was defined by incubating them with specific target cells (K562).

RESULTS

The percentage and the total number of CD8(+) lymphocytes were significantly higher in COPD smokers compared to non-COPD smokers (p = 0.01 and p = 0.005, respectively) or to healthy nonsmokers (p = 0.02 and p = 0.01, respectively). Perforin expression in CD8(+) cells was significantly higher in smokers with COPD compared to the other two groups (p = 0.001). Increased cytotoxic activity of T cells was also observed in induced sputum of patients with COPD in comparison to the other two groups.

CONCLUSION

CD8(+) cells are not only increased in number in sputum samples of smokers with COPD but are highly activated, expressing high levels of perforin. These findings suggest that CD8(+) T-lymphocytes play a significant role in the inflammatory process of COPD.

Induced sputum CD8+ T-lymphocyte subpopulations in chronic obstructive pulmonary disease

BACKGROUND

Previous studies have shown that the inflammatory response to cigarette smoking differs between smokers who develop chronic obstructive pulmonary disease (COPD) and those who do not and that the CD8+ T-lymphocytes have been identified as a key player in this process. The aim of this study was to investigate further the role of CD8+ cells and their subtypes in sputum cells.

METHODS

Sputum induction was performed in 36 COPD patients, 25 smokers without COPD and 10 non-smoking healthy controls. After stimulation of sputum lymphocytes with phorbol-myristate-acetate, we used double immunocytochemical methods to identify CD4+, CD8+ cells and CD8+ INFgamma or IL4 cells (Tc1,Tc2).

RESULTS

COPD patients had an increased number of CD8+ cells in sputum as compared with smokers without COPD (P = 0.0001) and control subjects (P = 0.001). CD8+-IL4 cells were reduced both in COPD and in smokers without COPD compared to controls (P = 0.0001), while CD8+-IFNgamma cells were significantly reduced only in COPD (P = 0.001) as compared with controls. A significant (P = 0.02) relationship between the CD8+-IL4/CD8+-IFNgamma ratio and FEV1 (% pred) was found only in COPD patients.

CONCLUSION

These findings suggest that an imbalance both in T-lymphocyte subpopulation (CD4/CD8) and in CD8+ cell subsets (Tc1/Tc2) characterizes the inflammatory responses of smokers with established COPD.

Bronchodilator effect of zafirlukast in subjects with chronic obstructive pulmonary disease

Cysteinyl leukotrienes (LT) are involved in airway inflammation and mucus hypersecretion, characteristically present in asthma and chronic obstructive pulmonary disease (COPD). Zafirlukast is an LT receptor antagonist that improves airway function within 1-3 h after oral administration in subjects with chronic persistent asthma. Through a randomised, double-blind, crossover and placebo-controlled study, we assessed the short-term effects of zafirlukast in patients with severe COPD. We enrolled 23 subjects (seven women) aged 59.4 (1.67) yr [mean (SEM)] with a smoking history of 60.7 (5.2) pack-yr. At screening day the mean FEV(1)was 0.876 (0.72) l; FEV(1) % predicted=35 (3)% and 107 (14) ml increment post-salbutamol. They came two different days, apart from each other at least 72 h. After baseline spirometry, a single oral dose of 40 mg zafirlukast or the corresponding placebo was administered. FVC and FEV(1) was measured every 30 min until 2 hrs. On zafirlukast day, the mean FEV(1) at 90 min [0.813 (0.64) l] and the mean FVC at 90 min [1.76 (0.1) l] were significantly higher than the respective means at placebo day (mean FEV(1)=0.747 (0.55) l; mean FVC=1.63 (0.1) l; p<0.05 Tukey Kramer multiple comparisons test). The maximum mean increase in FEV(1) was 75 (19) ml. A positive correlation was found between absolute response to salbutamol in FEV(1) and the response to zafirlukast (r=0.41; p<0.04). In conclusion, these findings suggest that zafirlukast has a bronchodilator or antibronchoconstrictor effect in COPD patients with severe airflow limitation.

Regulation of TNF‐α and IFN‐γ induced CXCL10 expression: participation of the airway smooth muscle in the pulmonary inflammatory response in chronic obstructive pulmonary disease

The chemokine CXCL10 is produced by many inflammatory cells found in the diseased lung and has been implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). The present study demonstrates elevated CXCL10 protein in the lungs of COPD patients, which appears histologically in airway smooth muscle (hASM). In primary cultured hASM cells taken from normal donors, CXCL10 protein expression was induced by IFN-gamma and TNF-alpha, cytokines reported as elevated in COPD, and a synergistic response was obtained when they were combined. TNF-alpha stimulation of hASM enhanced accumulation of CXCL10 mRNA, indicating regulation at the transcriptional level, while IFN-gamma stimulation resulted in a smaller accumulation of CXCL10 mRNA. When these cytokines were applied simultaneously, an additive effect was obtained. TNF-alpha-induced CXCL10 expression in hASM was dependent on NFkappaB activation, and a salicylanilide NFkappaB inhibitor blocked the CXCL10 expression. In contrast, IFN-gamma stimulation resulted in transient NFkappaB activation, and the inhibitor had little effect on CXCL10 expression. When these cytokines were added simultaneously, NFkappaB was activated earlier and lasted longer, and the effect was blocked by the inhibitor. These data demonstrate a potential active role for hASM in pulmonary inflammatory diseases such as COPD by producing CXCL10.

Antiinflammatory effects of the phosphodiesterase-4 inhibitor cilomilast (Ariflo) in chronic obstructive pulmonary disease

Cilomilast (Ariflo), a new oral phosphodiesterase-4 selective inhibitor, improves lung function in chronic obstructive pulmonary disease (COPD). We have evaluated its antiinflammatory effects in 59 patients with COPD randomized to receive cilomilast, 15 mg two times a day, or placebo for 12 weeks. Induced sputum differential cell counts were obtained at baseline and at five further visits. Interleukin-8 and neutrophil elastase were measured in sputum supernatant. Bronchial biopsies obtained at baseline and at Week 10 were immunostained and counted for neutrophils, CD8+ and CD4+ T-lymphocyte subsets, and CD68+ macrophages. Cells expressing the genes for interleukin-8 and tumor necrosis factor-alpha were identified by in situ hybridization and quantified. Compared with placebo, analysis of variance (ANOVA) of the change from baseline showed that cilomilast did not alter any sputum endpoint or FEV1. However, bronchial biopsies demonstrated that cilomilast treatment was associated with reductions in CD8+ (p = 0.001; ANOVA) and CD68+ cells (p < 0.05; ANOVA). In addition, by Poisson analysis, comparison of cell counts analyzed as a ratio of active to placebo demonstrated reductions of CD8+ (48% p < 0.01) and CD68+ (47% p = 0.001) cells. This is the first demonstration of reduction by any agent of airway tissue inflammatory cells characteristic of COPD. Phosphodiesterase-4 inhibitors represent a promising new class of substances for use in antiinflammatory treatment of this disease.

Increased production of TGF-beta and apoptosis of T lymphocytes isolated from peripheral blood in COPD

Chronic obstructive pulmonary disease (COPD) is associated with inflammation of airway epithelium, including an increase in the number of intraepithelial T cells. Increased apoptosis of these T cells has been reported in the airways in COPD, and although this process is critical for clearing excess activated T cells, excessive rates of apoptosis may result in unbalanced cellular homeostasis, defective clearance of apoptotic material by monocytes/macrophages, secondary necrosis, and prolongation of the inflammatory response. Lymphocytes are known to traffic between the airway and the peripheral circulation, thus we hypothesized that in COPD, circulating T cells may show an increased propensity to undergo apoptosis. We analyzed phytohemagglutinin (PHA)-stimulated peripheral blood T cells from COPD patients and controls for apoptosis using flow cytometry and staining with annexin V and 7-aminoactinomycin D. As several pathways are involved in induction of apoptosis of T cells, including transforming growth factor (TGF)-beta/TGF receptor (TGFR), TNF-alpha/TNFR1, and Fas/Fas ligand, these mediators were also investigated in peripheral blood samples from these subject groups. Significantly increased apoptosis of PHA-stimulated T cells was observed in COPD (annexin positive 75.0 +/- 14.7% SD vs. control 50.2 +/- 21.8% SD, P = 0.006), along with upregulation of TNF-alpha/TNFR1, Fas, and TGFR. Monocyte production of TGF-beta was also increased. In conclusion we have demonstrated the novel finding of increased apoptosis of stimulated T cells in COPD and have also shown that the increased T-cell death may be associated with upregulation of apoptotic pathways, TGF-beta, TNF-alpha, and Fas in the peripheral blood in COPD.

Induced sputum in the investigation of airway inflammation of COPD

During the last decade, the method of sputum induction (SI) has offered the opportunity to study inflammation in patients with chronic obstructive pulmonary disease (COPD). This paper reviews methodological aspects of SI and summarizes its uses in the research of inflammation in COPD, including sputum cellularity and soluble markers. SI is a relatively safe, reliable, and reproducible technique, used to investigate different aspects of airway inflammation. Although various methods of induction and processing have been proved safe and highly reproducible, a generally accepted method is needed. Sputum analysis has given evidence for increased numbers of macrophages and neutrophils in COPD patients compared to normal subjects. In some studies, increased numbers of eosinophils have been also reported. Changes in various mediators have been found in sputum supernatant of COPD patients (IL-8, LTB-4 and TNF-a). The clinical usefulness of the method in the follow-up of the disease has not been explored extensively. A number of observations in patients with different clinical characteristics could be proven useful in identifying patterns of inflammation associated with different prognosis. Finally, SI could also guide treatment; such as, sputum eosinophilia in COPD could predict response to inhaled corticosteroids.

Does a single dose of the phosphodiesterase 4 inhibitor, cilomilast (15 mg), induce bronchodilation in patients with chronic obstructive pulmonary disease?

Maintenance treatment with PDE(4) inhibitor cilomilast improves FEV(1) in chronic obstructive pulmonary disease (COPD) patients. We investigated the acute bronchodilating effects of a single dose of cilomilast with or without concomitant administration of inhaled salbutamol and/or ipratropium bromide in 21 patients with COPD (mean (SD) age 64 (8.1) y, post-salbutamol FEV(1) 47.7 (13.2) %predicted). FEV(1) was measured before and up to 8 hourly intervals after intake of placebo, cilomilast, or cilomilast in combination with inhaled salbutamol 400 microg and/or ipratropium bromide 80 microg. Maximum increase in FEV(1) from pre-dose baseline was calculated after each treatment and differences between treatment arms were analyzed by ANOVA. The mean (SEM) maximum increase in FEV(1) was 139.6 (18.5) ml following cilomilast and 151.5 (18.5) ml following placebo (95% C.I. for mean difference between cilomilast and placebo: -67.3, 43.6 ml). Furthermore, combined treatment of cilomilast with salbutamol or ipratropium resulted in a maximum increase in FEV(1) of 280.7 (25.6) and 297.0 (25.9) ml, respectively, while this was 379.0 (24.6) ml following cilomilast with both salbutamol and ipratropium (p < 0.01). We conclude that a single dose of cilomilast does not produce acute bronchodilation in patients with COPD who otherwise respond to inhaled bronchodilators. Our results implicate that the change in lung function seen after long-term treatment with cilomilast is not the result of acute bronchodilation in patients with COPD.

Structure and function of small airways in smokers: relationship between air trapping at CT and airway inflammation

PURPOSE

To use quantitative computed tomography (CT) to compare lung attenuation with both inflammatory infiltration and in vitro reactivity of peripheral airways in smokers scheduled to undergo lung resection for localized pulmonary lesions.

MATERIALS AND METHODS

Attenuation was measured in nine ex-smokers, 13 current smokers, and eight nonsmoking control subjects by using CT with respiratory gating and a contour-tracing algorithm. After lung resection in smokers, peripheral bronchi were dissected and studied in terms of both inflammation (by using immunohistochemistry to examine glycolmethacrylate-embedded specimens) and mechanical activity (by using an isolated organ bath system). Comparisons between groups were made by using analysis of variance and subsequent unpaired t tests. Correlations were evaluated by using the Pearson coefficient and stepwise multiple regression analysis.

RESULTS

The difference between inspiratory and expiratory attenuation was significantly higher in control subjects (-128 HU +/- 11 [SD]) than in ex-smokers (-77 HU +/- 10; P =.004) or current smokers (-67 HU +/- 11; P =.001). Cells infiltrating the smooth muscle increased with the decrease in expiratory attenuation (r = -0.46; P =.03) and the increase in inspiratory versus expiratory attenuation (r = 0.66; P =.001). Mast cell and neutrophil infiltration of smooth muscle was the most important factor in this relationship. Cellular infiltration of the smooth muscle increased with the decrease of in vitro relaxation response to salbutamol.

CONCLUSION

In smokers, air trapping is correlated with inflammatory infiltration of the smooth muscle layer of small airways.

Small airway morphology and lung function in the transition from normality to chronic airway obstruction

This study investigated the relationships between pathological changes in small airways (<6 mm perimeter) and lung function in 22 nonasthmatic subjects (20 smokers) undergoing lung resection for peripheral lesions. Preoperative pulmonary function tests revealed airway obstruction [ratio of forced expiratory volume in 1 s to forced vital capacity (FEV1/FVC) < 70%] in 12 subjects and normal lung function in 10. When all subjects were considered together, total airway wall thickness was significantly correlated with FEV1/FVC (r2 = 0.25), reactivity to methacholine (r2 = 0.26), and slope of linear regression of FVC against FEV1 values recorded during the methacholine challenge (r2 = 0.56). Loss of peribronchiolar alveolar attachments was significantly associated (r2 = 0.25) with a bronchoconstrictor effect of deep inhalation, as assessed from a maximal-to-partial expiratory flow ratio <1, but not with airway responses to methacholine. No significant correlation was found between airway smooth muscle thickness and lung function measurements. In conclusion, this study suggests that thickening of the airway wall is a major mechanism for airway closure, whereas loss of airway-to-lung interdependence may contribute to the bronchoconstrictor effect of deep inhalation in the transition from normal lung function to airway obstruction in nonasthmatic smokers.

New concepts in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a leading cause of death and disability but has only recently been explored from a cellular and molecular perspective. In COPD, chronic inflammation leads to fixed narrowing of small airways and alveolar wall destruction (emphysema). This is characterized by increased numbers of alveolar macrophages, neutrophils, and cytotoxic T lymphocytes, and the release of multiple inflammatory mediators (lipids, chemokines, cytokines, growth factors). There is also a high level of oxidative stress, which may amplify this inflammation. There is increased elastolysis and probable involvement of matrix metalloproteinases. The inflammation and proteolysis in COPD is an amplification of the normal inflammatory response to cigarette smoke. Unlike asthma, this inflammation appears to be resistant to corticosteroids, prompting a search for novel anti-inflammatory therapies that may prevent the relentless progression of the disease.

Airway structural alterations selectively associated with severe asthma

To identify airway pathologic abnormalities selectively associated with severe asthma, we examined 10 control subjects, 10 patients with intermittent asthma, 15 patients with mild-to-moderate persistent asthma, 15 patients with severe persistent asthma, and 10 patients with chronic obstructive pulmonary disease. Bronchial biopsies were assessed for epithelial integrity; subepithelial basement membrane (SBM) thickness; collagen type III deposition; eosinophil, neutrophil, and fibroblast numbers; mucous gland and airway smooth muscle (ASM) areas; SBM-ASM distance; ASM hypertrophy (increased cell size); and the expression of the contractile proteins alpha-actin, smooth muscle myosin heavy-chain isoforms, myosin light-chain kinase, and the phosphorylated form of the regulatory light chain of myosin. Neither mucosal eosinophilia nor neutrophilia, epithelial damage, or SBM thickness reflected asthma severity. In contrast, higher numbers of fibroblasts (p < 0.001), an increase in collagen type III deposition (p < 0.020), larger mucous gland (p < 0.040) and ASM (p < 0.001) areas, augmented ASM cell size (p < 0.001), and myosin light-chain kinase expression (p < 0.005) distinguished patients with severe persistent asthma from patients with milder disease or with chronic obstructive pulmonary disease. Stepwise multivariate regression analysis established that fibroblast numbers and ASM cell size were negatively associated with prebronchodilator and postbronchodilator FEV1 values in patients with asthma. We conclude that fibroblast accumulation and ASM hypertrophy in proximal airways are selective determinants of severe persistent asthma.

Transient receptor potential (TRP) channels as potential drug targets in respiratory disease

Calcium-permeable channels have traditionally been thought of as therapeutic targets in excitable cells. For instance, voltage-operated Ca2+ channels in neurones and smooth muscle cells for neurological and cardiovascular diseases although calcium-permeable channels are also functionally important in electrically non-excitable cells. In the lung, calcium channels play a pivotal role in the activation of all the cell types present, whether resident cells such as airway smooth muscle cells and macrophages or migratory cells such as neutrophils or lymphocytes.Previously, research in this area has been hindered by the lack of obvious molecular identity. More recently, the emergence of the transient receptor potential (TRP) cation family has yielded promising candidates which may underpin the different receptor-operated calcium influx pathways. The challenge now, is to ascribe function to the TRP channels expressed in each cell type as a first step in identifying which TRP channels may be potential drug targets for asthma and chronic obstructive pulmonary disease (COPD) (Fig. 1).

Accelerated decline of lung function in COPD patients with chronic hepatitis C virus infection: a preliminary study based on small numbers of patients

STUDY OBJECTIVES

It has been suggested that chronic viral infection may increase the risk for development of COPD. This prospective study was designed to determine that chronic hepatitis C virus (HCV) infection is associated with accelerated decline of lung function in patients with COPD, and that antiviral therapy against HCV is effective for such patients.

DESIGN

Prospective 5-year follow-up study.

SETTING

University hospital.

PATIENTS

Fifty-nine patients with COPD (group A, 15 HCV-negative ex-smokers; group B, 14 HCV-negative current smokers; group C, 14 HCV-positive ex-smokers; group D, 16 HCV-positive current smokers).

INTERVENTIONS

After a 5-year follow-up period, 21 HCV-positive patients received interferon (IFN)-alpha therapy.

MEASUREMENTS AND RESULTS

The rate of annual decline in FEV(1) and diffusing capacity of the lung for carbon monoxide (DLCO) during the 5-year follow-up period were significantly higher in group B (DeltaFEV(1), 59.7 mL/yr [SD, 17.5], p = 0.0008; DeltaDLCO, 3.50%/yr [SD, 0.44], p < 0.0001) and group C (DeltaFEV(1), 54.0 mL/yr [SD, 15.3], p = 0.0128; DeltaDLCO, 3.36%/yr [SD, 0.28], p < 0.0001) than in group A (DeltaFEV(1), 33.5 mL/yr [SD, 7.7]; DeltaDLCO, 2.66%/yr [SD, 0.34]). Moreover, these parameters in group D (DeltaFEV(1), 79.5 mL/yr [SD, 20.6]; DLCO, 4.5%/yr [SD, 0.40]) were also significantly higher than those in group B and group C. We evaluated the DeltaFEV(1) after IFN therapy during the 3-year follow-up period in the 8 IFN responders and 13 IFN nonresponders. DeltaFEV(1) in the IFN nonresponders did not significantly change during the 3-year follow-up period (before, 65.5 mL/yr [SD, 23.5]; after, 66.1 mL/yr [SD, 24.0]). However, DeltaFEV(1) in the IFN responders significantly decreased (before, 68.4 mL/yr [SD, 26.2]; after, 57.3 mL/yr [SD, 23.6], p = 0.0116).

CONCLUSIONS

Our findings suggest that chronic HCV infection might accelerate decline in lung function in patients who already have COPD.

Differences in airway inflammation in patients with fixed airflow obstruction due to asthma or chronic obstructive pulmonary disease

To determine whether patients with fixed airflow obstruction have distinct pathologic and functional characteristics depending on a history of either asthma or chronic obstructive pulmonary disease (COPD), we characterized 46 consecutive outpatients presenting with fixed airflow obstruction by clinical history, pulmonary function tests, exhaled nitric oxide, sputum analysis, bronchoalveolar lavage, bronchial biopsy, and high-resolution computed tomography chest scans. Subjects with a history of COPD (n = 27) and subjects with a history of asthma (n = 19) had a similar degree of fixed airflow obstruction (FEV1: 56 +/- 2 versus 56 +/- 3% predicted) and airway hyperresponsiveness (PC20FEV1: 2.81 [3.1] versus 1.17 [3.3]). Subjects with a history of asthma had significantly more eosinophils in peripheral blood, sputum, bronchoalveolar lavage, and airway mucosa; fewer neutrophils in sputum and bronchoalveolar lavage fluid; a higher CD4+/CD8+ ratio of T cells infiltrating the airway mucosa; and a thicker reticular layer of the epithelial basement membrane. They also had significantly lower residual volume, higher diffusing capacity, higher exhaled nitric oxide, lower high-resolution computed tomography scan emphysema score, and greater reversibility to bronchodilator and steroids. In conclusion, despite similar fixed airflow obstruction, subjects with a history of asthma have distinct characteristics compared with subjects with a history of COPD and should be properly identified and treated.

Acquired somatic mutations in the molecular pathogenesis of COPD

Chronic obstructive pulmonary disease (COPD) is caused mostly by cigarette smoking but its specific molecular mechanisms are obscure. Current theories suggest that the inflammation and oxidative stress induced by smoking lead to proteolytic imbalance and progressive lung structural derangement, with disease susceptibility being controlled by inherited variations in protective or inflammatory genes. However, cigarette smoke is directly mutagenic. Acquired somatic mutations, rather than inherited polymorphisms, might therefore be major determinants of COPD. Somatic mutations in oncogenes such as p53, Ras, EGFR and PTEN abound in the epithelium of smokers. These mutations are persistent, explaining the paradox that smoking cessation does not resolve inflammation. Moreover, the recognition that these somatic mutations converge on key inflammation, host defense and steroid response pathways might help to explain the clinical defects in these processes in COPD and guide discovery of future therapies.

Chronic obstructive pulmonary disease . 6: The aetiology of exacerbations of chronic obstructive pulmonary disease

Exacerbations of COPD are thought to be caused by interactions between host factors, bacteria, viruses, and changes in air quality to produce increased inflammation in the lower airway. The evidence for this and the potential mechanisms by which they result in the characteristic symptoms of exacerbations is reviewed. A better understanding of the causes and processes is needed for the appropriate use of existing treatments and the development of new ones. Future studies need to define populations clearly, stratify for known confounding factors, and should aim to identify clinical correlates so that clinical practice can be modified appropriately.

Sputum T lymphocytes in asthma, COPD and healthy subjects have the phenotype of activated intraepithelial T cells (CD69+ CD103+)

BACKGROUND

T cells of intraepithelial phenotype have previously been detected in bronchoalveolar lavage (BAL) fluid in a range of lung diseases; these cells express the adhesion molecule alpha(E)beta(7) integrin, CD103, the ligand for epithelial cell E-cadherin. In subjects with asthma CD4+ lymphocytes are the predominant T cell subtype found in bronchial biopsy specimens and in BAL fluid, whereas CD8+ lymphocytes have been shown to predominate in subjects with chronic obstructive pulmonary disease (COPD). The aim of this study was to analyse the expression of CD103, activation markers (CD25 and CD69), and chemokine receptors (CXCR3, CCR5 and CCR3) on CD4+ and CD8+ lymphocytes from sputum and peripheral blood of subjects with asthma, COPD, and healthy controls.

METHODS

T cell surface markers were assessed by immunofluorescence labelling and flow cytometry of gated lymphocytes among CD45+ leucocytes in sputum cell suspensions.

RESULTS

Sputum lymphocytes expressed higher levels of CD103 and CD69 than blood lymphocytes in all subject groups, with CD103 expressed at higher levels on CD8+ than on CD4+ cells. There were no detectable differences in numbers of CD4+ and CD8+ T cells between subjects with asthma, COPD and controls. The percentage of sputum lymphocytes expressing CXCR3 was lower in subjects with asthma or COPD than in healthy controls; CCR3 was not detectable on sputum or blood lymphocytes.

CONCLUSIONS

Sputum T lymphocytes are predominantly of activated intraepithelial phenotype (CD103+ CD69+), and normal numbers of CD4+ and CD8+ T cell populations are found in the sputum of patients with asthma and COPD.