Follicular bronchiolitis: a rare cause of bronchiolitis obliterans syndrome after lung transplantation: a case report

This case report is the first confirmed case of follicular bronchiolitis (FB), a rare bronchiolar disorder characterized by peribronchiolar lymphoid follicles, in a series of over 400 lung transplantations performed in our center. It is to our knowledge, the first publication describing FB after lung transplantation (LTx), presenting as chronic allograft dysfunction or bronchiolitis obliterans syndrome (BOS).

The role of the IL23/IL17 axis in bronchiolitis obliterans syndrome after lung transplantation

Bronchiolitis obliterans syndrome (BOS) is the leading cause of death after lung transplantation. Treatment is challenging, as the precise pathophysiology remains unclear. We hypothesize that T(H)17 lineage plays a key role in the pathophysiology of BOS by linking T-cell activation to neutrophil influx and chronic inflammation. In a cross-sectional study, bronchoalveolar lavage (BAL) samples of 132 lung transplant recipients were analyzed. Patients were divided in four groups: stable or suffering from infection (INF), acute rejection (AR) or BOS. The upstream T(H)17 skewing (TGF-beta/IL1beta/IL6/IL23), T(H)17 counteracting (IL2), T(H)17 effector cytokine (IL17) and the principal neutrophil-attracting chemokine (IL8), were quantified at the mRNA or protein level in combination with the cell profiles. The BOS group (n = 36) showed an increase in IL1beta protein (x1.5), IL6 protein (x3), transforming growth factor-beta (TGF-beta) mRNA (x3), IL17 mRNA (x20), IL23 mRNA (x10), IL8 protein (x2), IL8 mRNA (x3) and a decrease in IL2 protein (x0.8). The infection group (n = 11) demonstrated an increase in IL1beta protein (x5), IL6 protein (x20), TGF-beta mRNA (x10), IL17 mRNA (x300), IL23 mRNA (x200) and IL8 protein (x6). The acute rejection group (n = 43) only revealed an increase in IL6 protein (x6) and IL8 protein (x2) and a decrease in IL2 protein (x0.7). Lymphocytes and neutrophils were increased in all groups compared to the stable (n = 42). Our findings demonstrate the IL23/IL17 axis to be involved in the pathophysiology of BOS potentially triggering the IL8-mediated neutrophilia. IL6, IL1beta and IL23 seem to be skewing cytokines and IL2 a counteracting cytokine for T(H)17 alignment. The involvement of TGF-beta could not be confirmed, either as T(H)17 steering or as counteracting cytokine.

The role of the IL23/IL17 axis in bronchiolitis obliterans syndrome after lung transplantation

Bronchiolitis obliterans syndrome (BOS) is the leading cause of death after lung transplantation. Treatment is challenging, as the precise pathophysiology remains unclear. We hypothesize that T(H)17 lineage plays a key role in the pathophysiology of BOS by linking T-cell activation to neutrophil influx and chronic inflammation. In a cross-sectional study, bronchoalveolar lavage (BAL) samples of 132 lung transplant recipients were analyzed. Patients were divided in four groups: stable or suffering from infection (INF), acute rejection (AR) or BOS. The upstream T(H)17 skewing (TGF-beta/IL1beta/IL6/IL23), T(H)17 counteracting (IL2), T(H)17 effector cytokine (IL17) and the principal neutrophil-attracting chemokine (IL8), were quantified at the mRNA or protein level in combination with the cell profiles. The BOS group (n = 36) showed an increase in IL1beta protein (x1.5), IL6 protein (x3), transforming growth factor-beta (TGF-beta) mRNA (x3), IL17 mRNA (x20), IL23 mRNA (x10), IL8 protein (x2), IL8 mRNA (x3) and a decrease in IL2 protein (x0.8). The infection group (n = 11) demonstrated an increase in IL1beta protein (x5), IL6 protein (x20), TGF-beta mRNA (x10), IL17 mRNA (x300), IL23 mRNA (x200) and IL8 protein (x6). The acute rejection group (n = 43) only revealed an increase in IL6 protein (x6) and IL8 protein (x2) and a decrease in IL2 protein (x0.7). Lymphocytes and neutrophils were increased in all groups compared to the stable (n = 42). Our findings demonstrate the IL23/IL17 axis to be involved in the pathophysiology of BOS potentially triggering the IL8-mediated neutrophilia. IL6, IL1beta and IL23 seem to be skewing cytokines and IL2 a counteracting cytokine for T(H)17 alignment. The involvement of TGF-beta could not be confirmed, either as T(H)17 steering or as counteracting cytokine.

Type III IFN-lambda mRNA expression in sputum of adult and school-aged asthmatics

BACKGROUND

The increased susceptibility of asthmatics to rhinovirus infection has recently been related to deficient IFN-lambda 1 (IL-29) and IFN-lambda 2/3 (IL-28) production by bronchial epithelial cells and macrophages.

OBJECTIVES

Here, we studied IFN-lambda mRNA expression in the airways of stable asthmatics in comparison with healthy subjects and in relation to asthma symptoms, non-invasive parameters of airway inflammation and lung function parameters.

METHODS

Airway cells were obtained by sputum induction, in 14 healthy and 35 asthmatic adults and 12 asthmatic school-aged children. IFN-lambda was studied at the mRNA level by quantitative RT-PCR.

RESULTS

Asthmatic adults have increased sputum IL-28 mRNA but similar IL-29 mRNA expression in comparison with healthy subjects. In asthmatics, both sputum IL-28 and IL-29 mRNA expression correlate with the sputum CD3 gamma mRNA expression (reflecting infiltrated T cells). IL-28 (but not IL-29) mRNA levels correlate with the relative and absolute number of eosinophils present in the sputum sample. Sputum IL-29 mRNA (but not IL-28) correlates negatively with asthma symptoms in steroid-naive patients and is significantly higher in steroid-treated than in steroid-naive patients. Finally, both IL-28 and IL-29 mRNA levels are higher in asthmatic children than in asthmatic adults.

CONCLUSION

Our results show that asthmatic subjects have substantial type III IFN-lambda mRNA levels in the airways. Our data furthermore suggest that IL-29 could have an immunoprotective role in the lower airways.

Gastro-oesophageal reflux and aspiration of gastric contents in adult patients with cystic fibrosis

BACKGROUND

Gastro-oesophageal reflux (GOR) is increased in cystic fibrosis (CF), but its prevalence, characteristics, association with gastric aspiration and respiratory impact are not well characterised. We investigated acid and weakly acidic reflux, aspiration and respiratory symptoms/function in adult CF patients.

METHODS

Thirty-three CF patients [19 men; 29 (18-55) years, [10 post-lung transplant (LTx)] underwent impedance-pH monitoring for detection of acid (pH<4) and weakly acid GOR (pH 4-7). In 16 patients cough was objectively recorded with oesophageal manometry, and the symptom association probability (SAP) was calculated. Saliva and bronchoalveolar lavage fluid (BALF) were tested for bile acids.

RESULTS

Twenty-eight patients had increased GOR (21 acid, 5 weakly acidic and 2 acid+weakly acidic) and 10 had a positive SAP for reflux cough. GOR parameters were similar in non-LTx and post-LTx CF patients. The sequence reflux cough was significantly more common than cough reflux. Sixteen of 38 patients had bile acids in saliva and 6/10 in BALF and this was almost exclusively observed in patients with genotype DF508/DF508. Only 12/28 with increased GOR and 9/22 with bile acids in saliva/BALF had typical reflux symptoms. There was a positive correlation (r = 0.53, p = 0.03) between oesophageal acid exposure and cough. SAP-positive patients with for reflux cough had a lower lung function than SAP-negative patients.

CONCLUSION

Increased GOR is prevalent in CF and not secondary to cough. Acid GOR is common, but weakly acidic GOR may also occur. CF patients have a high risk of aspiration and reflux seems to be associated with more cough and poorer lung function. Outcome studies with intense anti-reflux therapy are needed to confirm the deleterious role of reflux in CF progression.

Sinonasal pathology in nonallergic asthma and COPD: 'united airway disease' beyond the scope of allergy

BACKGROUND

In contrast to the epidemiological and clinical association between allergic rhinitis and asthma, upper airway inflammation is less characterized in patients with nonatopic asthma and virtually unexplored in chronic obstructive pulmonary disease (COPD). Here, sinonasal pathology is studied in patients with allergic asthma, nonallergic asthma and COPD.

METHODS

Ninety patients with stable bronchial disease were included in the study, of which 35 were diagnosed with allergic asthma, 24 with nonallergic asthma and 31 with COPD. Concurrently, 61 control subjects without pulmonary disease were included and matched for age and smoking habits respectively with the asthma and the COPD group. Sinonasal symptoms were evaluated on a visual analogue scale and rhinosinusitis-related impairment of quality of life was assessed with the sino-nasal outcome test-22 (SNOT-22) questionnaire. Nasal mucosal abnormalities were quantified with nasal endoscopy and nasal secretions collected for measuring inflammatory mediators.

RESULTS

Allergic asthmatics, nonallergic asthmatics and COPD patients reported more nasal symptoms than their respective control subjects, had a higher SNOT-22 score and presented more mucosal abnormalities in the nose. Nasal secretions of both allergic and nonallergic asthmatics contained higher levels of eotaxin, G-CSF, IFN-gamma and MCP-1 than controls. Allergic asthmatics had higher nasal IP-10 levels as well. COPD-patients had higher nasal levels of eotaxin, G-CSF and IFN-gamma than controls.

CONCLUSION

Patients with allergic and nonallergic asthma and COPD show increased nasal symptoms and more nasal inflammation. Hence, our data confirm the 'united airways' concept to be beyond the scope of allergic asthma.

Gastro-oesophageal reflux and gastric aspiration in lung transplant patients with or without chronic rejection

Acid gastro-oesophageal reflux (GOR) and gastric aspiration have been labelled as risk factors for chronic rejection bronchiolitis obliterans syndrome (BOS) after lung transplantation (LTx). The present study aimed to further characterise GOR (both acid and nonacid) and the degree of gastric aspiration in LTx recipients both with and without BOS. Impedance-pH recordings were used for GOR detection. Pepsin and bile acid levels were measured in bronchoalveolar lavage fluid (BALF). A total of 48% of patients had increased GOR, of which 27% had exclusively increased nonacid reflux. Cystic fibrosis patients had the highest prevalence of GOR. Pepsin was found in BALF of all patients and bile acids in BALF of 50% of the patients. Patients with BOS had neither increased GOR nor elevated pepsin in BALF. However, 70% of the patients with BOS had bile in BALF compared with 31% of stable patients. Proton pump inhibitor (PPI) treatment reduced acid reflux but did not affect nonacid reflux. Moreover, pepsin and bile levels in BALF were not reduced by PPI. One-half of the lung transplant patients had increased reflux, and nonacid reflux was common. Gastric aspiration occurred in most lung transplant patients. Pepsin was a more general marker and bile acids a more specific marker that might be associated with bronchiolitis obliterans syndrome. Proton pump inhibitor treatment did not prevent nonacid reflux and gastric aspiration.

Transient airway colonization is associated with airway inflammation after lung transplantation

Lower airway tract colonization may trigger neutrophil-mediated airway inflammation. We investigated whether transient airway colonization influences airway inflammation and pulmonary function after lung transplantation (LTx). In this retrospective study, stable LTx patients with consecutive broncho-alveolar lavages (BAL), the first colonized and the second noncolonized, were included to create a Pooled group (P, n=32) and a Gram Negative (GN, n=14), Gram Positive (GP, n=9) and Fungi (F, n=9) subgroup. Similarly, LTx patients with consecutive, noncolonized BAL samples were included as Control group (C, n=19). BAL analysis (cell counts, IL6, IL8) and forced expiratory volume (FEV(1)) were compared between groups. In the P group and the GN subgroup, colonized BAL samples showed a significant increase in total cells, neutrophilia and IL8-concentration and a significant decrease in FEV(1), even when compared with the matched samples of the C group. A significant increase in neutrophilia was observed in the GP subgroup, but no other significant difference was found either in the GP and F subgroup or the C group. IL6 levels were not significantly different between groups. Transient airway colonization, especially with Pseudomonas-like GN bacteria, in stable LTx patients may be associated with IL8-dependent neutrophilic airway inflammation and a, albeit subtle, decrease in FEV(1).

Improved diagnosis of gastro-oesophageal reflux in patients with unexplained chronic cough

BACKGROUND

Symptoms, oesophageal pHmetry and proton pump inhibitor treatment are used for diagnosing gastro-oesophageal reflux-related cough. Weakly acidic reflux is now increasingly associated with reflux symptoms such as regurgitation or chest pain.

AIM

To study the association between weakly acidic reflux and cough in a selected, large group of patients with unexplained chronic cough.

METHODS

A total of 100 patients with chronic cough (77 'off' and 23 'on' a proton pump inhibitor) were studied using impedance-pHmetry for reflux detection and manometry for objective cough monitoring. Symptom Association Probability (SAP) Analysis characterized the reflux-cough association.

RESULTS

Acid reflux could be a potential mechanism for cough in 45 patients (with either heartburn, high acid exposure or +SAP for acid reflux). Weakly acidic reflux could be a potential mechanism for cough in 24 patients (with either increased oesophageal volume exposure, increased number of weakly acidic reflux or +SAP for weakly acidic reflux). Reflux could not be identified as a potential mechanism for cough in 31 patients.

CONCLUSION

A positive association between cough and weakly acidic reflux was found in a significant subgroup of patients with unexplained chronic cough. Impedance-pH-manometry identified patients in whom cough can be related to reflux that would have been disregarded using the standard diagnostic criteria for acid reflux.

Macrolides inhibit IL17-induced IL8 and 8-isoprostane release from human airway smooth muscle cells

Lung transplantation is hampered by bronchiolitis obliterans syndrome (BOS), although recently azithromycin treatment has a published response rate of about 42% in patients with established BOS. We linked this improvement to a reduction in airway neutrophilia and IL8. In the present study, we further investigated the intracellular mechanisms of azithromycin, looking at the possible involvement of mitogen-activated-protein kinases (MAPK) and oxidative stress. Simultaneously, currently used immunosuppressive agents were investigated. Human primary airway smooth muscle cells were stimulated with IL17 and incubated with increasing concentrations of steroids, immunosuppressive agents (tacrolimus, cyclosporine and rapamycin) or macrolides (erythromycin and azithromycin). We measured supernatant IL8 protein, 8-isoprostane and cell lysate MAPK. IL17-induced IL8 production was decreased by both erythromycin and azithromycin. In nonstimulated condition, IL8 production only increased at the highest dose of azithromycin. Dexamethasone failed to attenuate IL8 production, whereas immunosuppressive agents significantly increased IL8 production in both IL17-stimulated and nonstimulated conditions. 8-isoprostane production and MAPK activation proved to be decreased by the macrolides. We conclude that macrolides (but not steroids/immunosuppressive agents) inhibit IL17-induced IL8 production in human primary airway smooth muscle cells via a reduction in MAPK activation and 8-isoprostane production. In BOS patients, these phenomena may explain the anti-inflammatory effects of azithromycin.

The role of interleukin-17 during acute rejection after lung transplantation

Acute rejection (AR) is an important complication that can occur after lung transplantation and constitutes a risk factor for bronchiolitis obliterans syndrome, which is characterised by a neutrophilic airway inflammation. The specific aim of this study was to investigate the role of interleukin (IL)-17, which promotes chemotaxis of neutrophils by inducing IL-8 production, in AR. Cell differentials, mRNA and protein levels were quantified in bronchoalveolar lavages (BALs) taken from patients at 28 and 90 days after lung transplantation. The patient's rejection status was assessed by transbronchial biopsy. An AR was found in nine out of the 26 patients examined, 28 days after transplantation. The number of BAL neutrophils and lymphocytes were increased in these patients. IL-17 mRNA and protein levels in the BAL were increased in patients with AR. Analysis of BAL obtained at day 90 after transplantation, demonstrated that the increase in IL-17 had disappeared, whereas the increase in neutrophils and lymphocytes persisted. These data showed that interleukin-17 is temporarily upregulated in bronchoalveolar lavage during acute rejection. The number of lymphocytes and neutrophils are increased in bronchoalveolar lavage during acute rejection and may persist up to 2 months after acute rejection. These findings suggest that interleukin-17 is important in the pathophysiology of acute lung rejection.

The pH of exhaled breath condensate of patients with allograft rejection after lung transplantation

Endogenous airway acidification, as assessed by the condensate pH, has been implicated in the pathophysiology of inflammatory airway diseases such as cystic fibrosis and asthma. The aim of this study was to investigate the pH of condensate in patients after lung transplantation (LTX). From the cohort of transplanted patients at our center, 83 patients (9 heart-lung transplantation, 48 double-lung transplantation, 26 single-lung transplantation) were recruited and analyzed in a cross-sectional manner: 26 patients were diagnosed with chronic rejection or bronchiolitis obliterans syndrome (BOS), 7 patients were diagnosed with acute rejection (AR) while 50 patients had no evidence of rejection according to the International Society for Heart and Lung Transplantation criteria. The condensate pH was significantly reduced in patients with BOS and AR when compared to patients without rejection and control subjects (5.8 +/- 0.5 and 6.2 +/- 0.4 versus 6.6 +/- 0.4 and 6.5 +/- 0 .4, respectively; p < 0.05). Moreover, there was a significant correlation between condensate pH levels and the BOS grade (r =-0.62; p < 0.01), the FEV(1) (r = 0.39; p < 0.01) and the total cell and neutrophil count in bronchoalveolar lavage fluid (r =-0.39 and r =-0.56, respectively; p < 0.01). Airway acidification occurs in BOS and may directly or indirectly reflect airway inflammation in patients with allograft rejection after LTX. Measuring condensate pH might thus be a new tool for the evaluation of rejection in lung transplant patients.

Evaluation of airway inflammation by quantitative Th1/Th2 cytokine mRNA measurement in sputum of asthma patients

BACKGROUND

Asthma is a chronic inflammatory disorder of the airways driven by T cell activation. Th2 cells and their cytokines are thought to play a role in the pathophysiology of allergic as well as non-allergic asthma.

METHODS

Airway cells were obtained by sputum induction from 15 healthy and 39 asthmatic individuals and the airway T cell cytokine profiles (interleukin (IL)-4, IL-5, IL-13, IL-10 and interferon (IFN)-gamma) at the mRNA level were studied by real time RT-PCR.

RESULTS

Asthma patients had increased expression of IL-5 (p = 0.001) and IL-13 (p = 0.03) mRNA in sputum compared with non-asthmatic controls. IL-4 mRNA and IFN-gamma mRNA were detectable in the sputum of 44% and 21% of patients, respectively, but not in controls. Sputum IL-10 mRNA levels did not differ significantly between patients and controls. Sputum mRNA expression levels of IL-4, IL-5, and IL-13 were significantly correlated with the percentage of eosinophils and were higher in subjects with allergic asthma than in those with non-allergic asthma (p = 0.03, p = 0.02 and p = 0.0002, respectively); they did not differ between mild asthmatic subjects and those with moderate to severe asthma. In contrast, IFN-gamma mRNA expression was higher in non-allergic than in allergic patients (p = 0.04) and higher in patients with moderate to severe asthma than in those with mild asthma (p<0.01). Sputum IL-5 mRNA levels (but not the other cytokine mRNA levels) were also correlated with exhaled nitric oxide (eNO) and with bronchial hyperreactivity expressed as the histamine concentration resulting in a 20% decrease in forced expiratory volume in 1 second.

CONCLUSION

Real time RT-PCR analysis of mRNA in induced sputum confirms a predominance of Th2 cytokines in both allergic and non-allergic asthma. IL-5 levels reflect eosinophil infiltration as well as eNO levels and hyperreactivity, and levels of the Th1 cytokine IFN-gamma indicate asthma severity. The technique is a promising tool for use in further studies of asthma severity and disease activity.

Is it bronchiolitis obliterans syndrome or is it chronic rejection: a reappraisal?

Chronic rejection (obliterative bronchiolitis) is the single most important cause of chronic allograft dysfunction and late mortality after lung transplantation. As this condition is difficult to prove using biopsy specimens, a clinical term, bronchiolitis obliterans syndrome (BOS) has been in use for >10 yrs to describe the progressive decrease of pulmonary function. However, before diagnosing a patient as having BOS, based on a sustained and progressive decrease in forced expiratory volume in one second and/or forced mid-expiratory flow between 25-75% of forced vital capacity, different confounding factors have to be eliminated. Treatment of BOS mainly consists of an increase or a change in the immunosuppressive drug regimen, which may lead to more pronounced infectious complications. Recently, two new options have become available to treat patients with BOS, treatment of gastro-oesophageal reflux and azithromycin. In the present paper, the authors give an overview of the current data on these two modalities, which may lead to a restoration of the pulmonary function in some of the patients, illustrating once more the fact that bronchitis obliterans syndrome is not always a manifestation of chronic rejection.

Quantitative analysis of 8-isoprostane and hydrogen peroxide in exhaled breath condensate

Exhaled breath condensate (EBC) provides a noninvasive means of sampling the lower respiratory tract. Collection of EBC might be useful in the assessment of airway oxidative stress in smokers. The aim of this study was to determine 8-isoprostane and hydrogen peroxide levels in EBC, and, in addition, to investigate the reproducibility of these measurements. EBC samples were collected from 12 healthy male smokers at three time points within 1 week. 8-isoprostane and H2O2 were measured in nonconcentrated EBC using immunochemical and colorimetric assays, respectively. 8-isoprostane and H2O2 were detected in only 36 and 47% of all EBC samples, respectively. It was not possible to calculate the within-subject variation in a reliable manner since only three of the 12 smokers exhibited detectable 8-isoprostane concentrations on all three occasions (mean 4.6 pg x mL(-1); range 3.9-7.7 pg x mL(-1)), whereas H2O2 could not be detected on all three occasions in any of the smokers. Spiking experiments revealed a recovery of 83.5-109.5% for 8-isoprostane and 69.9-129.0%, for H2O2 in fresh EBC samples. It was concluded that levels of 8-isoprostane and hydrogen peroxide cannot be reproducibly assessed in exhaled breath condensate from healthy smokers because of their low concentration and/or the lack of sensitivity of the available assays.

Modulation by cAMP of IL-1beta-induced eotaxin and MCP-1 expression and release in human airway smooth muscle cells

Inflammatory cells, such as eosinophils, seem to be key players in the inflammatory process of asthma. These cells are attracted by chemokines, for example eotaxin and monocyte chemotactic protein (MCP-1). In this study, the authors investigated whether eotaxin and MCP-1 expression and release in human airway smooth muscle cells could be modulated by an increase in intracellular cyclic adenosine monophosphate (cAMP) concentration. The possible involvement of cAMP-dependent protein kinase A (PKA) was also studied. Forskolin, a direct stimulator of adenylyl cyclase, decreased the interleukin (IL)-1beta-induced eotaxin and MCP-1 release by 73+/-8 and 65+/-6%, respectively. 8Bromo-cAMP, a cAMP analogue, similarly decreased the chemokine production by 58+/-9 and 63+/-8% for eotaxin and MCP-1, respectively. Prostaglandin E2, known as an activator of the prostanoid receptors EP2 and EP4, which are positively coupled to adenylyl cyclase, also decreased the IL-1beta-induced eotaxin and MCP-1 production by 57+/-17 and 53+/-4%, respectively. H-89, an inhibitor of PKA, was able to inhibit the decrease in eotaxin and MCP-1 protein release induced by forskolin. Using Western-blot analysis, no effect of cAMP was found on the IL-1beta-induced p38 mitogen-activated protein kinase, extracellular signal-related kinase or cJun N-terminal kinase activation. This study shows that an increase in intracellular cyclic adenosine monophosphate concentration may decrease the interleukin-1beta-induced eotaxin and monocyte chemotactic protein-1 expression and production. This can be inhibited by addition of H-89, an inhibitor of cyclic adenosine monophosphate-dependent protein kinase. No decrease was observed in interleukin-1beta-induced p38 mitogen-activated protein kinase, extracellular signal-related kinase or cJun N-terminal kinase activation. These findings may be important for the further development of new anti-inflammatory drugs.

N-acetylcysteine reduces chemokine release via inhibition of p38 MAPK in human airway smooth muscle cells

Reactive oxygen species are involved in the activation of several mitogen-activated protein kinases (MAPKs), key-players in the production of several cytokines. Therefore the current study investigated whether N-acetylcysteine (NAC), an antioxidative agent, inhibits the interleukin (IL)-1beta-induced expression and production of eotaxin and monocyte chemotactic protein (MCP)-1 in human airway smooth muscle cells (HASMC). NAC (10 mM) decreased the expression of eotaxin and MCP-1, by 46 +/- 11% (n=7) and 87 +/- 4% (n=6), respectively; the eotaxin release was inhibited by 75 +/- 5% (n=7), whereas the MCP-1 release was decreased by 69 +/- 41% (n=10). NAC (1 mM) also decreased the IL-1beta-induced activation of p38 MAPK. Compared with unstimulated cells, a four-fold increase in 8-isoprostane production in IL-1beta-stimulated HASMC was observed, which could be inhibited by NAC in a concentration-dependent way, with a maximum inhibition of 39 +/- 12%, with 1 mM NAC. The present study demonstrated that N-acetylcysteine inhibits the interleukin-1beta-induced eotaxin and monocyte chemotactic protein 1 expression and production due to a decreased activation of p38 mitogen-activated protein kinase. This study has also shown that N-acetylcysteine decreases the interleukin-1beta-induced production of reactive oxygen species, as suggested by a reduction in the 8-isoprostane production.

Exhaled nitric oxide after lung transplantation: impact of the native lung

It has already been demonstrated that exhaled nitric oxide (eNO) is increased in lung transplant patients with chronic rejection, although it is not known whether the diseased native lung after single lung transplantation (SLTx) contributes to the increased eNO values. This study aimed to compare the eNO values in stable lung transplant patients (SLTx versus sequential (S)SLTx and heart (H)LTx) and in patients with established chronic rejection. Altogether, 42 LTx patients (25 females, 13 SLTx, 18 SSLTx, 11 HLTx), with a mean follow-up of 1149 days and a mean age of 44.6 yrs at transplantation, were included. Twenty-six patients had no signs of chronic rejection (five SLTx and 21 SSLTx/HLTx). There was no difference in their eNO values (10.2 in SLTx versus 12.2 (parts per billion) ppb in SSLTx/HLTx). Sixteen patients (eight SLTx and eight SSLTx/HLTx) had a chronic rejection (eight bronchiolitis obliterans syndrome (BOS) potential stage, four BOS stage 1, three BOS stage 2 and one BOS stage 3). Their eNOs were 18.1 (SLTx) and 17.0 (SSLTx/HLTx) ppb, respectively, which were significantly different to the stable LTx patients and showed a trend towards significance for SSLTx/HLTx. There was no significant difference in eNO between the patients with chronic rejection who underwent SLTx and those who underwent SSLTx/HLTx. The diseased native lung after single lung transplantation probably does not contribute much to the exhaled nitric oxide values, either in stable lung transplant patients or in lung transplant patients with chronic rejection.

Mechanisms of interleukin 1beta-induced human airway smooth muscle hyporesponsiveness to histamine. Involvement of p38 MAPK NF-kappaB

We have investigated the effect of IL-1beta on histamine H(1)-receptor (H(1)R)-mediated inositol phosphate (IP) accumulation in human airway smooth muscle cells (HASMC) and on histamine-induced contraction of human bronchial rings. Stimulation of HASMC for 24 h with IL-1beta resulted in significant loss of histamine-induced IP formation, which was associated with a reduction of histamine- induced contraction of IL-1beta-treated human bronchial rings. An inhibitor of NF-kappaB activation, pyrrolidine dithiocarbamate, and a p38 MAPK inhibitor, blocked the IL-1beta-induced H(1)R desensitization, whereas anisomycin, an SAPK/JNK and p38 MAPK activator, mimicked the effect of IL-1beta. IL-1beta has been demonstrated to induce cox-2 expression and PGE(2) synthesis. In our study, indomethacin a cox antagonist, completely inhibited the effect of IL-1beta on H(1)R, whereas exogenously added PGE(2) was able to desensitize H(1)R. Furthermore, H-89, a selective PKA inhibitor, antagonized the effect of IL-1beta. Here, we have demonstrated that IL-1beta desensitizes H(1)R, which involves the activation of p38 MAPK and NF-kappaB, leading to the expression of cox-2 and the synthesis of PGE(2). PGE(2) increases intracellular cAMP resulting in PKA activation, which phosphorylates and functionally uncouples H(1)R. Our results suggest that IL-1beta protects airway smooth muscle against histamine-induced contractile responses and that bronchial hyperreactivity to histamine is not associated with proinflammatory cytokine-induced enhancement in H(1)R signaling.

Epinastine (WAL 801CL) inhibits the electrical field stimulation-induced cholinergic contraction in guinea pig and human airways in vitro

Epinastine is an antihistamine drug with binding affinities at 5-hydroxytryptamine (5-HT) receptors. The current study was performed to investigate whether epinastine could modulate the cholinergic contraction in guinea pig and human airways in vitro. Isolated guinea pig and human airway preparations were suspended in organ baths containing modified Krebs-Henseleit solution. Electrical field stimulation was applied to elicit cholinergic contractions. Epinastine produced a concentration-dependent inhibition of the cholinergic contraction in guinea pig airways and pretreatment with methysergide (5-HT1/2/7 antagonist) significantly attenuated these inhibitory effects of epinastine. Pretreatment with tropisetron (5-HT3/4 antagonist), ketanserin (5-HT2 antagonist), SDZ216-525 (5-HT1A antagonist) or phentolamine (alpha-adrenergic antagonist) had no effect. Epinastine did not displace the concentration-response curve to acetylcholine. These results suggest that epinastine inhibits the cholinergic contraction in guinea pig airways through stimulation of prejunctional 5-hydroxytryptamine receptors, located to postganglionic cholinergic nerves. Inhibitory effects of epinastine on the cholinergic contraction in human airways in vitro were also demonstrated, which suggests that a similar mechanism might be present in human airways. The pharmacological profile of epinastine, which shows binding affinity at the 5-hydroxytryptamine7 receptor but not at the 5-hydroxytryptamine1 receptor subtypes corroborates the hypothesis that the inhibitory prejunctional 5-hydroxytryptamine receptor on cholinergic nerves is of the 5-hydroxytryptamine7 subtype.

Expression of monocyte chemotactic protein (MCP)-1, MCP-2, and MCP-3 by human airway smooth-muscle cells. Modulation by corticosteroids and T-helper 2 cytokines

We have demonstrated that, in addition to their contractile function, human airway smooth-muscle cells (HASMC) are able to express and to secrete chemokines of the monocyte chemotactic protein (MCP)/ eotaxin subfamily. This group of chemokines is believed to play a fundamental role in the development of allergic airway diseases such as asthma. The expression levels of MCP (MCP-1, -2, and -3) messenger RNA (mRNA) were compared with those of regulated on activation, normal T cells expressed and secreted (RANTES) mRNA in HASMC in culture. HASMC express MCP and RANTES mRNA after stimulation with interleukin (IL)-1beta, tumor necrosis factor-alpha, and interferon-gamma. MCP mRNA was maximal at 8 h, whereas RANTES mRNA expression was delayed to 24 h after stimulation. Further, significant differences were observed in the induction patterns of MCP and RANTES mRNA expression after stimulation with the individual cytokines. Dexamethasone (DEX) significantly inhibited cytokine-induced accumulation of MCP and RANTES mRNA, in contrast to IL-4, IL-10, and IL-13, which had no inhibitory effect on cytokine-induced chemokine expression. The cytokine-induced MCP mRNA expression in HASMC was associated with MCP release, which was inhibited by DEX and post-translationally by IL-4. HASMC can actively participate in the pathogenesis of asthma by the expression and release of chemokines, which are likely to play a critical role in the generation and regulation of the inflammatory response characteristic of allergic airway diseases.

The effects of 5-HT on cholinergic contraction in human airways in vitro

Inhaled 5-hydroxytryptamine (5-HT) causes bronchoconstriction in asthmatics, and 5-HT plasma levels are elevated in asthma. Electrical field stimulation (EFS) of human airways, in vitro, evokes cholinergic contraction mediated by the release of acetylcholine (Ach) from postganglionic cholinergic nerves. The present study investigates whether selective 5-HT agonists and antagonists can modulate EFS-induced cholinergic contraction in human airways in vitro. Human airways, obtained from resections for bronchial carcinoma or organ transplant donors, were suspended under 2-g tension, between two platinum wire electrodes, in carbogenated Krebs solution at 37 degrees C and EFS was applied (1-32 Hz, 50 V, 0.5 ms, 15 s every 4 min) to elicit cholinergic contractions. 5-HT (10 microM-0.3 mM) produced frequency- and concentration-dependent facilitation of cholinergic contraction, but did not displace the concentration/response curve to Ach. Tropisetron (1 microM), a 5-HT3 and 5-HT4 antagonist, completely blocked the facilitatory effect of 5-HT (100 microM), whereas both ondansetron (1 microM) and GR 125478D (1 microM), a selective 5-HT3 and 5-HT4 antagonist, respectively, also attenuated the 5-HT-induced enhancement of cholinergic contraction. This facilitatory effect of 5-HT was partially mimicked by both selective 5-HT3 (2-methyl-5-HT) and 5-HT4 (RS 67333 and 5-methoxytryptamine) agonists. Fluoxetine (10 microM), a 5-HT uptake inhibitor, had no effect on the 5-HT (10-100 microm) induced potentiation of cholinergic contraction. These findings suggest that 5-HT facilitates cholinergic contraction in human airways in vitro through stimulation of both prejunctional 5-HT3 and 5-HT4 receptors. This may implicate a role of 5-HT in asthma.