Measures of bronchodilator response of FEV1, FVC and SVC in a Swedish general population sample aged 50-64 years, the SCAPIS Pilot Study.

BACKGROUND: Data are lacking from general population studies on how to define changes in lung function after bronchodilation. This study aimed to analyze different measures of bronchodilator response of forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC) and slow vital capacity (SVC). MATERIALS AND METHODS: Data were derived from the Swedish Cardiopulmonary Bioimage Study (SCAPIS) Pilot study. This analysis comprised 1,050 participants aged 50-64 years from the general population. Participants were investigated using a questionnaire, and FEV1, FVC and SVC were recorded before and 15 minutes after inhalation of 400 µg of salbutamol. A bronchodilator response was defined as the relative change from baseline value expressed as the difference in units of percent predicted normal. Predictors of bronchodilator responses were assessed using multiple linear regression models. Airway obstruction was defined as FEV1/FVC ratio below lower limit of normal (LLN) before bronchodilation, and COPD was defined as an FEV1/FVC ratio below LLN after bronchodilation. Physician-diagnosed asthma was defined as an affirmative answer to "Have you ever had asthma diagnosed by a physician?". Asymptomatic never-smokers were defined as those not reporting physician-diagnosed asthma, physician-diagnosed COPD or emphysema, current wheeze or chronic bronchitis and being a lifelong never-smoker. RESULTS: Among all subjects, the greatest bronchodilator responses (FEV1, FVC and SVC) were found in subjects with asthma or COPD. The upper 95th percentile of bronchodilator responses in asymptomatic never-smokers was 8.7% for FEV1, 4.2% for FVC and 5.0% for SVC. The bronchodilator responses were similar between men and women. In a multiple linear regression model comprising all asymptomatic never-smokers, the bronchodilator response of FEV1 was significantly associated with airway obstruction and height. CONCLUSION: When the bronchodilator response in asymptomatic never-smokers is reported as the difference in units of predicted normal, significant reversibility of FEV1, FVC and SVC to bronchodilators is ~9%, 4% and 5%, respectively.

Treatment of idiopathic pulmonary fibrosis: a position paper from a Nordic expert group.

Idiopathic pulmonary fibrosis (IPF) is a fatal progressive lung disease occurring in adults. In the last decade, the results of a number of clinical trials based on the updated disease classification have been published. The registration of pirfenidone and nintedanib, the first two pharmacological treatment options approved for IPF, marks a new chapter in the management of patients with this disease. Other nonpharmacological treatments such as lung transplantation, rehabilitation and palliation have also been shown to be beneficial for these patients. In this review, past and present management is discussed based on a comprehensive literature search. A treatment algorithm is presented based on available evidence and our overall clinical experience. In addition, unmet needs with regard to treatment are highlighted and discussed. We describe the development of various treatment options for IPF from the first consensus to recent guidelines based on evidence from large-scale, multinational, randomized clinical trials, which have led to registration of the first drugs for IPF.

Increased intraepithelial (CD103+) CD8+ T cells in the airways of smokers with and without chronic obstructive pulmonary disease.

T cells are accumulated in the lungs of chronic obstructive pulmonary disease (COPD) patients. Intraepithelial T cells, expressing the integrin αE (CD103) ß7, and regulatory T cells have been implicated in pathogenesis of the disease. We asked whether COPD patients and smokers have altered frequencies of these T cells and if their phenotypes differ. A total of 40 never-smokers, 40 smokers with normal lung function and 38 COPD patients (GOLD I and II), of which 11 were ex-smokers, were included. T cells in bronchoalveolar lavage (BAL) fluid and peripheral blood were analysed for the expression of CD103, FOXP3 and markers of activation and differentiation using multi-colour flow cytometry. Smokers, regardless of airway obstruction, had significantly more CD8+CD103+ cells in their BAL fluid compared to never-smokers but less of those cells were CD27+CD69-. Smokers, in particular those with chronic bronchitis, had a higher percentage of CD4+FOXP3+ T-regulatory BAL cells compared to never-smokers and COPD ex-smokers. Chronic cigarette smoking leads to an accumulation of CD8+ T cells with an altered phenotype in the airway epithelium. The increased frequency of regulatory T cells may influence the ability to regulate smoke-induced inflammation which could be decisive for disease development. Our results further indicate a reversibility of smoke-induced changes.

Health effects of a subway environment in healthy volunteers.

Environmental particle exposure, often estimated as the particulate mass of particles with a diameter <10 microm, <2.5 microm or <1 microm (PM(10), PM(2.5) or PM(1)), is known to have a negative impact on the health of the population. Little is known about how the size and origin of particles influence the effects. We have previously shown that exposure to a road tunnel environment causes a cellular inflammatory response in the airways of healthy individuals. In the present study, our aim was to investigate potential airway health effects from exposure to a subway environment. 20 healthy volunteers were exposed to a subway and a control environment for 2 h, followed by measurements of lung function and the inflammatory response in the lower airways (bronchoscopy) and in the peripheral blood. No cellular response was found in the airways after exposure to the subway environment. In the blood, we found a statistically significant increase in fibrinogen and regulatory T-cells expressing CD4/CD25/FOXP3. Subway and road tunnel environments have similar levels of PM(10) and PM(2.5), whilst the concentrations of ultrafine particles, nitrogen monoxide and dioxide are lower in the subway. Although no cellular response was detected, the findings indicate a biological response to the subway environment. Our studies show that using gravimetric estimates of ambient particulate air pollution alone may have clear limitations in health-risk assessment.

Eosinophil cationic protein stimulates migration of human lung fibroblasts in vitro.

Asthma is characterized by eosinophilic inflammation and remodelling of the airways. Eosinophil cationic protein (ECP) is a protein released by activated eosinophils and the hypothesis that ECP contributes to the development of structural changes in the airways of asthmatics has been posed. Fibroblast recruitment is an important step in the remodelling process, and we therefore put the question whether ECP stimulates migration of human lung fibroblasts. Human peripheral eosinophils isolated from buffycoats from healthy individuals were cultured and conditioned media (CM) were collected. Native ECP was extracted from human peripheral eosinophils by gel filtration, ion-exchange and chelating chromatography. The ability of eosinophil CM and ECP to stimulate fibroblast migration was determined using the 48-well Boyden chamber. ECP concentrations in CM were assayed by ECP-CAP-FEIA. Both CM and ECP significantly stimulated fibroblast migration (48.4+/-cells/field versus 33+/-2 and 36+/-6 versus 25+/-4; P<0.001 and 0.05 respectively) in a time- and concentration-dependent manner. Adding neutralizing ECP antibodies attenuated fibroblast migration induced by both ECP as well as CM. ECP stimulates migration of human lung fibroblasts, suggesting a potential mechanism for eosinophils in the fibrotic response. This may be an important mechanism by which ECP promotes remodelling of extracellular matrix leading to airway fibrosis in asthmatics.

Increased levels of nerve growth factor in the airways of patients with sarcoidosis.

OBJECTIVES: Nerve growth factor (NGF) is a potent neuronal growth factor with inflammatory properties that recently has been proposed to be of importance in airway pathology. A role for NGF in the inflammatory granulomatous lung disease sarcoidosis is not well elucidated. The aims of this study were to investigate the secreted levels of NGF in bronchoalveolar lavage fluid (BALF) from sarcoidosis patients compared with patients with resolved disease, patients with another granulomatous disease--chronic beryllium disease (CBD)--and healthy subjects and also to investigate the relationship between NGF levels and markers of inflammation. METHODS AND RESULTS: NGF levels in BALF from 56 patients with active sarcoidosis (22 with Löfgren's syndrome), nine subjects with resolved sarcoidosis, six patients with CBD, and 31 healthy subjects were compared. A 10-fold elevation of NGF levels was found in patients with active sarcoidosis compared with subjects with clinically resolved sarcoidosis, patients with CBD and healthy subjects. In sarcoidosis patients, positive correlations between concentrations of NGF and lymphocytes, eosinophils and interferon-gamma, interleukin (IL)-4, IL-10, IL-12 were found. CONCLUSIONS: We demonstrate that secreted levels of NGF are markedly enhanced in the airways in active pulmonary sarcoidosis. Furthermore, a relationship between NGF and pulmonary inflammation in sarcoidosis is supported.

Smoking increases peptidylarginine deiminase 2 enzyme expression in human lungs and increases citrullination in BAL cells.

OBJECTIVES: A gene-environment interaction between HLA-DR shared epitope genes and smoking in anti-cyclic citrullinated peptide antibody-positive rheumatoid arthritis (RA) has been reported. Identification of citrullinated proteins in bronchoalveolar lavage (BAL) cells from smokers has led to the suggestion that citrullination induced by smoking might be the first step in the pathogenic chain of RA. OBJECTIVE: To confirm and extend these findings. METHODS: Immunohistochemistry was performed on BAL cells and bronchial mucosal biopsy sections obtained through bronchoscopy from 14 healthy smokers and 16 healthy non-smokers. Two antibodies recognising citrullinated proteins, two antibodies recognising peptidylarginine deiminase (PAD)2 enzyme and one recognising PAD4 enzyme were used. RESULTS: Citrullinated proteins are upregulated in BAL cells of healthy smokers compared with healthy non-smokers. This was associated with higher expression of the PAD2 enzyme. The same level of citrullinated proteins was present in bronchial mucosal biopsy specimens of healthy smokers and non-smokers, despite higher expression of PAD2 in smokers. CONCLUSION: This study provides evidence that smoking enhances PAD2 expression in the bronchial mucosal and alveolar compartment, with consequent generation of citrullinated proteins in the latter. Smoking is an environmental factor that may lead to citrulline autoimmunity in genetically susceptible subjects.

Human T cells stimulate fibroblast-mediated degradation of extracellular matrix in vitro.

Several chronic diseases are characterized by inflammation, T cell recruitment and tissue remodelling. We hypothesized that activated T cells may stimulate remodelling of extracellular matrix (ECM) in vitro. Total T cells (CD3+) as well as CD4+ and CD8+ subsets were isolated from peripheral blood and stimulated, after which conditioned media (CM) were obtained. CM was added to human lung fibroblasts in three-dimensional collagen gels and the area of gels was measured daily. Hydroxyproline was determined as a measure of collagen degradation in the gels. Matrix metalloproteinase (MMP) activity in the culture media was analysed by gelatine zymography. Cytokine secretion of stimulated CD4+ and CD8+ T cells was analysed. CD3+ CM augmented collagen gel contraction in a time- and dose-dependent manner (P < 0.0001). CD4+ T cell CM was more potent than CD8+ T cell CM (P < 0.001). CD3+ CM and CD4+ T cell CM, but not CD8+ T cell CM, stimulated fibroblast-mediated collagen degradation and MMP-9 activity. A broad-spectrum MMP-inhibitor added to the culture system inhibited both gel contraction and MMP activity. Activated CD4+ T cells secreted significantly more tumour necrosis factor (TNF) and interleukin (IL)-6 compared to CD8+ T cells. CD3+ CM from patients with chronic obstructive pulmonary disease stimulated fibroblast-mediated collagen gel contraction to the same magnitude as CD3+ CM from healthy controls. In conclusion, activated CD4+ T cells can stimulate fibroblast-mediated degradation of ECM in vitro. This could be a mechanism by which activated T cells stimulate degradation of lung tissue leading to pulmonary emphysema.

Road tunnel air pollution induces bronchoalveolar inflammation in healthy subjects.

Traffic-related air pollution is associated with adverse respiratory effects. The aim of the present study was to investigate whether exposure to air pollution in a road tunnel causes airway inflammatory and blood coagulation responses. A total of 16 healthy subjects underwent bronchoscopy with bronchial mucosal biopsies and bronchoalveolar lavage (BAL) on two occasions, in random order: once at 14 h after a 2-h exposure to air pollution in a busy road tunnel, and once after a control day with subjects exposed to urban air during normal activities. Peripheral blood was sampled prior to bronchoscopy. The road tunnel exposures included particulate matter with a 50% cut-off aerodynamic diameter of 2.5 microm, particulate matter with a 50% cut-off aerodynamic diameter of 10 mum and nitrogen dioxide which had median concentrations of 64, 176 and 230 microg.m(-3), respectively. Significantly higher numbers of BAL fluid total cell number, lymphocytes and alveolar macrophages were present after road tunnel exposure versus control. Significantly higher nuclear expression of the transcription factor component c-Jun was found in the bronchial epithelium after exposure. No upregulation of adhesion molecules or cellular infiltration was present and blood coagulation factors were unaffected. In conclusion, exposure of healthy subjects to traffic-related air pollution resulted in a lower airway inflammatory response with cell migration, together with signs of an initiated signal transduction in the bronchial epithelium.

Different inflammatory cell pattern and macrophage phenotype in chronic obstructive pulmonary disease patients, smokers and non-smokers.

Smokers exhibit airway inflammation and increased number of alveolar macrophages (AM), but not all develop chronic obstructive pulmonary disease (COPD). We hypothesized that AMs in COPD patients have an altered functional capacity mirrored in a different phenotype. Sixteen steroid-naive COPD patients [forced expiratory volume in 1 s (FEV(1)) < 70% of predicted] underwent bronchoalveolar lavage (BAL). Age- and smoking-matched non-obstructive smokers (n = 10) and healthy non-smokers (n = 9) served as controls. Nine COPD patients had a BAL cell yield sufficient for flow cytometry analysis, where expression of AM cell surface markers reflecting various functions was determined. AMs from COPD patients showed decreased expression of CD86 (co-stimulation) and CD11a (adhesion) compared to smokers' AMs (P < 0.05). Furthermore, smokers' AMs showed lower (P < 0.05) expression of CD11a compared to non-smokers. AM expression of CD11c was higher in the COPD and smokers groups compared to non-smokers (P < 0.05). The expression of CD54 (adhesion) was lower in smokers' AMs compared to non-smokers (P < 0.05), whereas CD16 was lower (P < 0.05) in COPD patients compared to non-smokers. The AM expression of CD11b, CD14, CD58, CD71, CD80 and human leucocyte antigen (HLA) Class II did not differ between the three groups. The AM phenotype is altered in COPD and further research may develop disease markers. The lower AM expression of CD86 and CD11a in COPD implies a reduced antigen-presenting function. Some alterations were found in smokers compared to non-smokers, thus indicating that changes in AM phenotype may be associated with smoking per se. The functional relevance of our findings remains to be elucidated.

Red blood cells increase secretion of matrix metalloproteinases from human lung fibroblasts in vitro.

Tissue remodeling is an important process in many inflammatory and fibrotic lung disorders. RBC may in these conditions interact with extracellular matrix (ECM). Fibroblasts can produce and secrete matrix components, matrix-degrading enzymes (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). Imbalance in matrix synthesis/degradation may result in rearrangement of tissue architecture and lead to diseases such as emphysema or fibrosis. Neutrophil elastase (NE), a protease released by neutrophils, is known to activate MMP. We hypothesized that RBC can stimulate secretion of MMPs from human lung fibroblasts and that NE can augment this effect. Human fetal lung fibroblasts were cultured in floating collagen gels with or without RBC. After 4 days, the culture medium was analyzed with gelatin zymography, Western blot, and ELISA for MMP-1, -2, -3 and TIMP-1, -2. RBC augmented NE-induced fibroblast-mediated collagen gel contraction compared with NE alone (18.4+/-1.6%, 23.7+/-1.4% of initial gel area, respectively). A pan-MMP inhibitor (GM-6001) completely abolished the stimulating effect of NE. Gelatin zymography showed that RBC stimulated MMP-2 activity and that NE enhanced conversion to the active form. Addition of GM-6001 completely inhibited MMP-2 activity in controls, whereas it only partially altered RBC-induced MMP activity. Western blot confirmed the presence of MMP-1 and MMP-3 in fibroblasts stimulated with RBC, and ELISA confirmed increased concentrations of pro-MMP-1. We conclude that stimulation of MMP secretion by fibroblasts may explain the ability of RBC to augment fibroblast-mediated collagen gel contraction. This might be a potential mechanism by which hemorrhage in inflammatory conditions leads to ECM remodeling.

Bronchoalveolar lavage in COPD: fluid recovery correlates with the degree of emphysema.

Bronchoscopy with bronchoalveolar lavage (BAL) is an important research tool for assessing airway inflammation in a variety of inflammatory lung diseases. In chronic obstructive pulmonary disease (COPD), BAL recovery is often low, making analysis of the recovered fluid difficult to interpret. The present authors hypothesised that the degree of emphysema may predict BAL recovery. A total of 20 COPD patients (mean age 57 yrs, range 49-69) with a median (interquartile range) forced expiratory volume in one second (FEV1) of 51 (33-69)% predicted underwent BAL. Matched "healthy" smokers and nonsmokers served as controls. Emphysema index in COPD patients was calculated on computed tomography scan as the percentage of the right lung with pixels <-950 Hounsfield units. The carbon monoxide diffusing capacity of the lung (DL,CO) was determined by the single-breath method. COPD patients had lower BAL recovery than controls. COPD patients with an emphysema index <1 had higher BAL recovery than patients with an emphysema index >1. BAL recovery correlated negatively to emphysema index and positively to DL,CO. However, no correlation was found between recovery and FEV1. In conclusion, the extent of emphysema evaluated by computed tomography-scan index and carbon monoxide diffusing capacity of the lung may predict a low bronchoalveolar lavage recovery in chronic obstructive pulmonary disease patients. These parameters may, therefore, be useful when chronic obstructive pulmonary disease patients are selected for bronchoscopy with bronchoalveloar lavage. The present study underlines the importance of careful phenotyping of chronic obstructive pulmonary disease patients.

Red blood cells inhibit proliferation and stimulate apoptosis in human lung fibroblasts in vitro.

Cell proliferation and apoptosis are both important mechanisms for the regulation of tissue homeostasis. For instance, proliferation is crucial in wound repair, whereas apoptosis is important for removal of damaged cells and resolution of inflammation. Imbalance between cell proliferation and apoptosis can therefore lead to pathological conditions and disease. In inflammatory and fibrotic lung disorders, red blood cells (RBCs) can interact with fibroblasts and connective tissue. In the present study, we therefore hypothesized that the presence of RBCs can affect fibroblast proliferation and apoptosis. Human foetal lung fibroblasts (HFL-1) were cultured in the presence or absence of purified whole RBCs and RBC-conditioned media. RBC significantly decreased fibroblast proliferation as determined both by DNA content analysis (Hoechst 33258 staining, P < 0.01; WST-1, P < 0.001) and BrdU incorporation. After treatment with staurosporine (STS) for 48 h, apoptosis was determined by TUNEL and propidium iodide staining followed by flow cytometry analysis. RBCs augmented STS-induced apoptosis (median: 46.4%; range 12.0-90.4) compared to control cells (median 26.2%; range 7.1-45.5). Thus, our data indicate that the presence of RBCs affects both fibroblast proliferation and susceptibility to undergo apoptosis. Our findings therefore suggest a role for RBCs in regulating fibroblast homeostasis after tissue injury.

The effect of eosinophils on collagen gel contraction and implications for tissue remodelling.

Asthma is characterized by an eosinophilic inflammation and a subepithelial fibrosis in the airways. Eosinophils contain several cytotoxic substances, such as eosinophil cationic protein (ECP), which can promote inflammation and cause tissue damage. This has generated the hypothesis that eosinophils may drive remodelling of extracellular matrix (ECM). To investigate the role of eosinophils we used an in vitro model for remodelling, the three-dimensional collagen gel contraction assay. Two sources of eosinophils were used in this study, isolated human peripheral eosinophils (purity > 95%) and stimulated [interleukin (IL)-5, IL-3 and granulocyte macrophage-colony stimulating factor (GM-CSF)] HL-60 clone 15 cells. Human eosinophils or HL-60 cells were cast together with human lung fibroblasts (HFL1) in type I collagen gels. Both types of eosinophils augmented fibroblast-mediated collagen gel contraction in a time and concentration-dependent manner. At 48 h, the gel area in HFL1/eosinophil co-culture was 46.5% +/- 0.5 (mean +/- s.e.m.) of initial area and in HFL1 culture 52.3% +/- 0.1 (P < 0.001). Respective figures for HFL1/stimulated HL-60 co-culture and HFL1 culture only were 44.1% +/- 0.5 and 52.4% +/- 0.4 (P < 0.001). The release of ECP was increased when fibroblasts were cultured with eosinophils compared to eosinophils cultured alone. In addition, native ECP added to fibroblast gel cultures also augmented contraction. Our results suggest that eosinophils may interact with mesenchymal cells, promoting remodelling of ECM and that ECP constitutes one potential eosinophil-derived mediator driving this process. We conclude that this may be one important mechanism by which eosinophil-ECM interactions will lead to airway tissue remodelling in asthma.

Red blood cells stimulate human lung fibroblasts to secrete interleukin-8.

Following lung injury, red blood cells (RBC) may interact with extracellular matrix (ECM). Fibroblasts, the resident cell in the ECM, have the capacity to produce and secrete a variety of mediators including interleukin-8 (IL-8). In the present study we hypothesized that RBC, or soluble factors released from them, may stimulate IL-8 production by fibroblasts. Fibroblasts were cultured in a three-dimensional collagen gel culture system in the presence or absence of RBC or conditioned medium from RBC (RBC-CM). IL-8 release from fibroblasts was significantly increased when cultured with RBC or RBC-CM and both tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) further stimulated this IL-8 secretion. The enhanced production of IL-8 within fibroblasts was accompanied by increased IL-8 mRNA expression. To evaluate whether RBC-fibroblast interaction may lead to recruitment of neutrophils, a functional migration assay was performed. RBC and RBC-CM, in the presence of IL-1beta and TNF-alpha, increased the transmigration of neutrophils. Our results indicate that RBC, when interacting with ECM, may participate in the recruitment of inflammatory cells by stimulating fibroblasts to secrete IL-8. This might be an important mechanism regulating tissue repair after injury.

Red blood cells stimulate fibroblast-mediated contraction of three dimensional collagen gels in co-culture.

OBJECTIVE AND DESIGN: Following injury, red blood cells (RBC) may interact with extracellular matrix (ECM). In the present study we hypothesised that RBC, and soluble factors from RBC, might mediate remodelling of ECM by affecting fibroblast-mediated contraction of three dimensional collagen gels. MATERIALS AND METHODS: Human lung fibroblasts (HFL-1), were cultured together with isolated RBC, conditioned medium from RBC (RBC-CM) and hemolysed RBC in type I collagen gels. Gel contraction was determined by an image analyser. RESULTS: Both RBC, RBC-CM and hemolysed RBC stimulated gel contraction by fibroblasts (P < 0.001), compared to fibroblasts alone. The RBC-CM stimulated (P < 0.01) gel contraction in a time and concentration dependent manner. A similar effect was observed when supernatant from hemolysed RBC was tested. The production of fibronectin was increased (P < 0.01) in the co-culture system, compared to fibroblasts cultured alone. CONCLUSIONS: The present study shows that RBC can interact with mesenchymal cells in vitro. The ability of RBC to modulate fibroblast-mediated contraction in vitro, might therefore be an important mechanism regulating repair processes after injury.

Determination of cardiac involvement in sarcoidosis by magnetic resonance imaging and Doppler echocardiography.

OBJECTIVES: To elucidate whether cardiac magnetic resonance imaging (MRI) could be useful in disclosing structural changes in the myocardium in sarcoidosis patients and to relate echo-Doppler derived indices of left ventricular function to electrocardiogram (ECG) findings. DESIGN: The MRI was performed in 18 consecutive patients with sarcoidosis. Left ventricular ejection fraction (LVEF), i.e. systolic function, was estimated echocardiographically by Simpson's two-dimensional method (n = 16). Diastolic function was estimated by age-corrected Doppler-derived indices: isovolumetric relaxation time (IVRT), deceleration time (DT) and early filling/atrial contraction ratio (E/A ratio). RESULTS: Eleven patients had conduction defects or dysrhythmias (ECG+) whilst seven patients had a normal ECG (ECG-). In two patients, high signalling, contrast-enhanced, isolated regions, suggestive of deposits, were seen in the left ventricular myocardium on MRI. Both these patients had abnormal ECGs and signs of systolic and/or diastolic dysfunction on echocardiography. LVEF was subnormal in seven of 10 of the ECG+ patients and in two of six of the ECG-. Signs of diastolic dysfunction were found in 59% and 56% of the measurements in the ECG+ and ECG- patients, respectively. CONCLUSION: We conclude (i) that myocardial deposits on MRI in sarcoidosis patients have a high specificity for cardiac involvement but a rather low sensitivity; (ii) that a substantial proportion of sarcoidosis patients with abnormal ECGs have echocardiographic signs of systolic and/or diastolic dysfunction.

Cigarette smoke inhibits human bronchial epithelial cell repair processes.

By interfering with the ability of airway epithelial cells to support repair processes, cigarette smoke could contribute to alterations of airway structures and functions that characterize chronic obstructive pulmonary disease (COPD). The current study assessed the ability of cigarette smoke extract (CSE) to alter human airway epithelial cell chemotaxis, proliferation, and contraction of three-dimensional collagen gels, a model of extracellular matrix remodeling. The volatile components contained in cigarette smoke, acetaldehyde and acrolein, were able to inhibit all three processes. Nonvolatile components contained within lyophilized CSE also inhibited chemotaxis but displayed no activity in the other two bioassays. CSE also inhibited the ability of airway epithelial cells to release transforming growth factor (TGF)-beta and fibronectin. Exogenous fibronectin was unable to restore epithelial cell contraction of collagen gels. Exogenous TGF-beta partially restored the ability of airway epithelial cells to contract collagen gels and to produce fibronectin. This supports a role for inhibition of TGF-beta release in mediating the inhibitory effects of cigarette smoke. Taken together, the results of the current study suggest that epithelial cells present in the airways of smokers may be altered in their ability to support repair responses, which may contribute to architectural disruptions present in the airways in COPD associated with cigarette smoking.

Interactions between monocytes and smooth-muscle cells can lead to extracellular matrix degradation.

BACKGROUND: Chronic infiltration of the airway wall with inflammatory cells characterizes both asthma and chronic bronchitis. Remodeling of the airway wall is also a feature of both diseases. OBJECTIVE: We hypothesized that collagen degradation may take place during coculture of monocytes with smooth-muscle cells (SMCs) and that this degradation might be altered by agents that modify the inflammatory regimen. METHODS: Monocytes (4.5 x 10(5)/mL) were cast into collagen gels containing human airway SMCs (4.5 x 10(5)/mL) and released into serum-free Dulbecco's modified Eagle's medium containing neutrophil elastase. Collagen content was quantified as total insoluble hydroxyproline on day 5. Zymography and immunoblotting were used to detect matrix metalloproteinases. RESULTS: Monocytes cocultured with SMCs in 3-dimensional native type I collagen gels produced TNF-alpha and IL-1beta and resulted in collagen degradation (30.5 vs 17.9 mg per gel) through inducing matrix metalloproteinase 1, 2, and 9 by means of SMCs. PGE(2) was significantly increased in coculture (0.9 vs 10.5 ng/mL). Indomethacin (1 micromol/L) completely inhibited PGE(2) production but augmented collagen degradation (17.9 vs 2.3 microg per gel), and this was blocked by the addition of exogenous PGE(2). Dexamethasone also inhibited collagen degradation in coculture. CONCLUSION: The current study supports the concept that interactions among cells present in the airway inflammatory milieu that characterize airway disease can lead to alterations in tissue structure and suggests mechanisms by which therapeutic strategies can be designed to modify tissue remodeling.

Collaborative interactions between neutrophil elastase and metalloproteinases in extracellular matrix degradation in three-dimensional collagen gels.

BACKGROUND: Extended culture of monocytes and fibroblasts in three-dimensional collagen gels leads to degradation of the gels (see linked study in this issue, "Fibroblasts and monocytes contract and degrade three-dimensional collagen gels in extended co-culture"). The current study, therefore, was designed to evaluate production of matrix-degrading metalloproteinases by these cells in co-culture and to determine if neutrophil elastase could collaborate in the activation of these enzymes. Since co-cultures produce prostaglandin E2 (PGE2), the role of PGE2 in this process was also evaluated. METHODS: Blood monocytes from healthy donors and human fetal lung fibroblasts were cast into type I collagen gels and maintained in floating cultures for three weeks. Matrix metalloproteinases (MMPs) were assessed by gelatin zymography (MMPs 2 and 9) and immunoblotting (MMPs 1 and 3). The role of PGE2 was explored by direct quantification, and by the addition of exogenous indomethacin and/or PGE2. RESULTS: Gelatin zymography and immunoblots revealed that MMPs 1, 2, 3 and 9 were induced by co-cultures of fibroblasts and monocytes. Neutrophil elastase added to the medium resulted in marked conversion of latent MMPs to lower molecular weight forms consistent with active MMPs, and was associated with augmentation of both contraction and degradation (P < 0.01). PGE2 appeared to decrease both MMP production and activation. CONCLUSION: The current study demonstrates that interactions between monocytes and fibroblasts can mediate tissue remodeling.