Cigarette smoke decreases the expression of secretory component in human bronchial epithelial cells, in vitro.

Epithelial secretory component (SC) is thought to be essential for immunologic protection of the respiratory tract from viral and bacterial infection, since it transports polymeric IgA from the basolateral to the luminal surface of epithelial cells. We have hypothesized that recurrent infection in airways of cigarette smokers is at least partly a consequence of cigarette smoke-induced downregulation of the expression and/or release of SC from airway epithelial cells, subsequently resulting in decreased transcytosis of secretory IgA to the airway lumen. To test this hypothesis, we have cultured human bronchial epithelial cells (HBEC) from surgical tissues and exposed these for 20 minutes to either air or cigarette smoke. Following exposure to cigarette smoke the HBEC cultures were incubated for a further period of up to 24 h, during which time separate cultures were processed by immunocytochemistry for the presence of SC, in a time-dependent manner. The stained HBEC cultures were evaluated by colour image analysis for the percentage of total cells staining for SC. Exposure to cigarette smoke significantly decreased the percentage of total HBEC staining for secretory component from a baseline value (median and interquartile[IQ]1, IQ3) of 35.9% (26.5, 41.6) to 15.7% (8.2, 25.4; p < 0.05) 1 h after exposure, compared with exposure to air. The percentage of cells staining for secretory component were further reduced to 5.3% (3.3, 6.4; p < 0.01), 6 h after exposure, compared to exposure to air. After incubation for 24 h following exposure to cigarette smoke, there was gross cell damage and the cells were not suitable for immunocytochemical analysis. These results suggest that short-term exposure to cigarette smoke may compromise the immune barrier function of the airway mucosa by decreasing the expression and/or release of epithelial SC, thereby decreasing the transcytosis of IgA necessary for inactivating the microbial pathogens in the airway lumen.

Interaction of cigarette smoke and house dust mite allergens on inflammatory mediator release from primary cultures of human bronchial epithelial cells.

Several studies have shown that exposure to cigarette smoke and/or house dust mite (HDM) can lead to increased airway inflammation in susceptible individuals. The underlying mechanisms, however, are not defined. To investigate the interaction between cigarette smoke and HDM allergen on mediator release from primary cultures of human bronchial epithelial cells. Confluent human bronchial epithelial cell cultures were exposed to cigarette smoke in the absence or presence of HDM allergen and investigated for the release of IL-8, IL-1beta, and sICAM-1. Damage to the epithelial cells themselves was assessed by release of 51Cr. On separate occasions, we investigated the effect of PTL11028, a highly potent and selective Der p1 inhibitor, on HDM allergen-induced release of IL-8, following activation of HDM allergen by incubation with cysteine. The effect of cigarette smoke exposure on the stability of these released mediators in prepared solutions in the absence/presence of reduced glutathione was also studied. Both HDM allergens and short-term (20 min) cigarette smoke exposure led to a significantly increased release of IL-8, IL-1beta and sICAM-1 from the epithelial cell cultures. Longer exposure (1-6 h) to cigarette smoke led to a dramatic decrease in the amount of these mediators detected in the culture medium. Whilst incubation of epithelial cultures with HDM allergen did not cause any significant change in the release of 51Cr from pre-loaded cells, cigarette smoke on its own led to a marked, exposure and incubation-time dependent increase in the release of 51Cr. Incubation with HDM allergen led to a significant, dose and time-dependent increase in the release of IL-8, which was further enhanced when the allergen extract was pre-activated with cysteine. This effect was completely abrogated by PTL11028, a novel Der p1 inhibitor. Prepared solutions of various concentrations of IL-8, IL-1beta and sICAM-1 exposed to cigarette smoke demonstrated a dramatic exposure time-dependent decrease in the detectable amount of these mediators, an effect which was abrogated by GSH. HDM-induced airway inflammation may include Der p-mediated release of inflammatory mediators from epithelial cells. Additionally, short-term cigarette smoke exposure may induce airway inflammation by release of inflammatory mediators from these cells, an effect which may be potentiated by Der p allergens. Longer term cigarette smoke exposure may cause damage to epithelial cells and changes in the structure of inflammatory mediators.

A randomized, double-blind, crossover comparison among cetirizine, levocetirizine, and ucb 28557 on histamine-induced cutaneous responses in healthy adult volunteers.

BACKGROUND: Cetirizine is a highly efficacious and long-acting second-generation H1-receptor antagonist for the treatment of allergic diseases, such as allergic rhinitis and chronic idiopathic urticaria, in adults and children. Pharmacologic studies have demonstrated that cetirizine, a racemate mixture composed of equal amounts of two enantiomers, does not undergo hepatic metabolism to any significant level. The enantiomers are excreted mainly unchanged, predominantly in the urine and to a lesser extent in the faeces. METHODS: The pharmacologic activity and potency of the two enantiomers of cetirizine in the management of allergic skin conditions were investigated by studying the effect of treatment with 5.0 mg cetirizine; 2.5 mg levocetirizine, the (R)-enantiomer; and 2.5 mg ucb 28557, the (S)-enantiomer, on histamine-induced wheal and flare response in 18 healthy volunteers. Each treatment was administered as a single oral dose in randomized, double-blind, and crossover manner, and the efficacy of treatment was assessed over a period of 32 h, as per cent inhibition of the histamine-induced wheal and flare areas before treatment. Blood and urine samples were collected in a time-dependent manner and analyzed for the total amounts of each study drug, to elucidate their pharmacokinetic profiles. RESULTS: Both cetirizine and levocetirizine caused a marked inhibition of histamine-induced wheal and flare, whereas ucb 28557 was inactive in this model. Inhibition of the wheal response observed for cetirizine and levocetirizine was apparent by 1 h after dosage and lasted for mean durations of 24.4 and 28.4 h, respectively. In addition, the response for cetirizine and levocetirizine became maximal by 6 h after treatment, rising to 79.5% and 83.8%. Similarly, cetirizine and levocetirizine also markedly inhibited the histamine-induced flare response. This effect was evident for both drugs by 1 h after dosage and lasted over a mean period of 28.4 and 26.0 h, respectively, for cetirizine and levocetirizine. The inhibitory effect of these compounds on histamine-induced flare response was also maximal by approximately 6 h after dosage, peaking at 88.5%) and 83.6%, respectively. Statistical evaluation showed that cetirizine and levocetirizine were equivalent for maximum inhibition of histamine-induced wheal and flare. However, levocetirizine was found to be superior to cetirizine when area under the curve was compared. In contrast, ucb 28557 was not found to inhibit histamine-induced wheal and flare responses at any time during the study period. Plasma concentrations of levocetirizine were found to be approximately double those of ucb 28557 at 4 and 8 h after dosing, and 50-60% of the drugs were excreted unchanged in urine over a period of 32 h. CONCLUSIONS: The finding that, in this model, levocetirizine 2.5 mg has comparable antihistaminic activity to cetirizine 5 mg, whereas its other enantiomer ucb 28557 has no pharmacodynamic effect, suggests that the antihistaminic properties of cetirizine observed in the management of allergic skin conditions are likely to be attributable to levocetirizine.

Effect of Variable Inspiratory Flow Rate on the Performance of the Budesonide Rhinocort Turbuhaler™.

OBJECTIVE: To investigate the effect of variable nasal inspiratory flow rates in vitro on total drug delivery and deposition patterns of budesonide delivered from the Rhinocort Turbuhaler™. METHODS: The total dose of budesonide delivered at flow rates of 15, 30 and 60 L/min and the particle size distribution of the delivered drug at flow rates of 28 and 60 L/min were determined at regular intervals throughout the life of six Rhinocort Turbuhalers™, each containing 200 × 100µ,g doses of budesonide. The delivered dose was determined by drawing individual doses of budesonide through separate G0120 Filtrete electrostatic filters. Acascade impactor was used to determine the particle size distribution of the delivered drug. RESULTS: The amount of budesonide delivered from each Turbuhaler™ device was variable throughout the life of the devices and was dependent on the inspiratory flow rate. Variability was greatest at the lower flow rates and decreased slightly with increasing inspiratory flow rate. Similarly, the particle size distribution of budesonide throughout the cascade impactor was variable and dependent on the flow rate. CONCLUSION: This study suggested that the efficiency of the Rhinocort Turbuhaler™ device in the management of allergic rhinitis may be influenced by the severity of nasal symptoms, particularly rhinorrhoea and nasal blockage, which determine the peak nasal inspiratory flow rates in symptomatic individuals.

Effect of cigarette smoke on the permeability and IL-1beta and sICAM-1 release from cultured human bronchial epithelial cells of never-smokers, smokers, and patients with chronic obstructive pulmonary disease.

Although cigarette smoking is of paramount importance in the development of chronic obstructive pulmonary disease (COPD), only a small proportion of smokers develop the disease. We tested the hypothesis that the response of the bronchial epithelium to cigarette smoke (CS) differs in patients with COPD. Such a difference might explain in part why only some cigarette smokers develop the disease. We established primary explant cultures of human bronchial epithelial cells (HBEC) from biopsy material obtained from never-smokers who had normal pulmonary function, smokers with normal pulmonary function, and smokers with COPD, and exposed these for 20 min to CS or air. Measurements were subsequently made over a period of 24 h of transepithelial permeability and release of interleukin (IL)-1beta and soluble intercellular adhesion molecule-1 (sICAM-1). In addition, intracellular reduced glutathione (GSH) levels were measured after 24 h incubation. Exposure to CS increased the permeability of these cultures in all study groups, but the most marked effect was observed in cultures from patients with COPD (mean increase, 85.5%). The smallest CS-induced increase in the permeability was observed in HBEC cultured from smokers with normal pulmonary function (mean, 25.0%), and this was significantly lower than that of HBEC from never-smokers (mean, 53.4%) (P<0.001). Compared with exposure to air, exposure to CS led to a significantly increased release of these mediators from cultures of the never-smoker group (mean 250.0% increase in IL-1beta and mean 175.3% increase in sICAM-1 24 h after exposure) and COPD group (mean 383.3% increase in IL-1beta and mean 97.4% increase in sICAM-1 24 h after exposure). In contrast, CS exposure did not influence significantly the release of either mediator from the cells of smokers with normal pulmonary function. Levels of intracellular GSH were significantly higher in cultures of HBEC derived from smokers, both those with normal pulmonary function and those with COPD, compared with cultures from healthy never-smokers. Exposure to CS significantly decreased the concentration of intracellular GSH in all cultures. However, the fall in intracellular GSH was significantly greater in cells from patients with COPD (mean 72.9% decrease) than in cells from never-smokers (mean 61.4% decrease; P = 0.048) or smokers with normal pulmonary function (mean 43.9% decrease; P = 0.02). These results suggest that whereas smokers with or without COPD demonstrate increased levels of GSH within bronchial epithelial cell cultures, those with COPD have a greater susceptibility to the effects of CS in reducing GSH levels and causing increased permeability and release of proinflammatory mediators such as IL-1beta and sICAM-1.

Airway epithelial cells, cytokines, and pollutants.

The airway epithelium is a complex physicochemical barrier that plays a pivotal role in host defense. Epithelial cells have been shown to be a rich source of several classes of modulatory compounds, of which the cytokines form the largest group and possibly play the most important role in the etiology of airway disease. Evidence suggests that there are differences in the airway epithelial cells of individuals with and without respiratory disease, both with regard to (1) their capacity to express and release different types and quantities of specific cytokines and (2) their reactivity to inhaled irritants. Consequently, it is tempting to speculate that differences in epithelial cell function are an important determinant of the predisposition to respiratory disease. However, whether the differences are a result of an intrinsic defect, an acquired property due to the disease process itself, or a combination of the two, remains to be determined. In view of advances that have been made in the understanding of the putative underlying mechanisms in airway diseases, it should be possible to formulate novel therapeutic agents in the form of specific monoclonal antibodies directed against specific proinflammatory cytokines. Mills PR, Davies RJ, Devalia JL. Airway epithelial cells, cytokines, and pollutants.

Effect of antihistamines on epithelial cells.

Antihistamines have mostly been used in the management of allergic rhinitis, primarily for their symptomatic relief. Recent studies, however, have suggested that the non-sedating second-generation antihistamines also possess anti-inflammatory activity, and consequently may be useful in the management of inflammation in allergic airways disease. Several in vivo studies have demonstrated that antihistamines decrease inflammatory cell infiltration in allergic disease, mediator release from mast/basophil cells, and the expression of adhesion molecules on epithelial cells. Similarly, in vitro studies have demonstrated that antihistamines decrease the migration and activation of eosinophils and the release of pro-inflammatory mediators from mast/basophil cells, induced by immunological and non-immunological stimuli. More recent evidence suggests that the antihistamines may modulate airway inflammation by influencing the activity of airway epithelial cells, which due to their spatial arrangement and predominance in the airways, are thought to play a pivotal role in the aetiology of airway disease. We and others have demonstrated that antihistamines attenuate allergen- or chemical-induced expression and/or release of mediators which influence the activity of inflammatory cells, such as eosinophils, mast cells, basophils and lymphocytes, known to be involved in the pathogenesis of allergic airway diseases. Collectively, these studies suggest that second-generation H1-histamine receptor antagonists may have potential use either as safe anti-inflammatory alternatives to corticosteroids, or as rescue medication in combination with corticosteroids, for the management of severe airway disease.

The effect of exposure to ozone and nitrogen dioxide on the airway response of atopic asthmatics to inhaled allergen: dose- and time-dependent effects.

Eleven mild atopic asthmatic patients were exposed for 6 h, in randomized order, to air, 100 ppb O3, 200 ppb NO2, and 100 ppb O3 + 200 ppb NO2, followed immediately by bronchial allergen challenge. Subsequently 10 of these patients were exposed for 3 h to air, 200 ppb O3, 400 ppb NO2, and 200 ppb O3 + 400 ppb NO2, followed immediately by bronchial allergen challenge. All exposures were carried out in an environmental chamber, with intermittent moderate exercise, and a minimal interval of 2 wk. Exposure for 6 h to 100 ppb O3, 200 ppb NO2, and 100 ppb O3 + 200 ppb NO2 did not lead to any significant increase in the airway response of these individuals to inhaled allergen, when compared with exposure for 6 h to air. In contrast, exposure for 3 h to 200 ppb O3, 400 ppb NO2, and 200 ppb O3 + 400 ppb NO2 significantly decreased the dose of allergen (in log cumulative breath units [CBU]) required to decrease FEV1 by 20% (allergen PD20FEV1), compared with exposure to air (geometric mean CBU: 3.0 for air versus 2.66 for O3 [p = 0.002]; 2.78 for NO2 [p = 0. 018]; 2.65 for O3 + NO2 [p = 0.002]). These results suggest that the pollutant-induced changes in airway response of mild atopic asthmatics to allergen may be dependent on a threshold concentration rather than the total amount of pollutant inhaled over a period of time.

Effect of loratadine on nitrogen dioxide-induced changes in electrical resistance and release of inflammatory mediators from cultured human bronchial epithelial cells.

BACKGROUND: Recent studies have demonstrated that some antihistamines can attenuate histamine-induced release of inflammatory mediators from bronchial epithelial cells. OBJECTIVE: The purpose of study was to test the hypothesis that loratadine may influence pollution-induced inflammation of the airways by modulating epithelial membrane integrity and the synthesis and/or release of inflammatory mediators from airway epithelial cells. METHODS: We have cultured human bronchial epithelial cell (HBEC) cultures from surgical explants and investigated the effect of loratadine on NO2-induced changes in both electrical resistance of HBEC cultures and release of IL-8, RANTES, and soluble intercellular adhesion molecule-1 (sICAM-1) from these cells after exposure for 6 hours to either air or 400 ppb NO2. RESULTS: Exposure for 6 hours to NO2 significantly decreased the electrical resistance of HBEC cultures by 18.1% from baseline (P <.05). Incubation with 0.25 to 25 micromol/L loratadine did not alter the NO2-induced decrease in the electrical resistance of HBEC cultures. NO2 also significantly increased the release of IL-8 from a control value of 52.5 pg/microgram cellular protein to 81.9 pg/microgram cellular protein (P <.05), RANTES from a control value of 0.023 pg/microgram cellular protein to 0.062 pg/microgram cellular protein (P <.05), and sICAM-1 from a control value of 7.7 pg/microgram cellular protein to 16.3 pg/microgram cellular protein (P <.05). The NO2-induced release of all 3 mediators was significantly attenuated by incubation of HBECs with 25 micromol/L loratadine. Incubation with 2.5 micromol/L loratadine also significantly attenuated the NO2-induced release of RANTES and sICAM-1, but not IL-8. CONCLUSIONS: These results suggest that loratadine has the potential to reduce airway inflammation by modulating the release of inflammatory cytokines from airway epithelial cells.

Cigarette smoke potentiates house dust mite allergen-induced increase in the permeability of human bronchial epithelial cells in vitro.

Although studies have suggested that exposure to cigarette smoke (CS) may be associated with the development of atopy, the mechanisms underlying this are not clearly understood. It has been suggested that CS impairs the barrier function of the airway epithelium, leading to increased access of allergens such as those of the house dust mite (HDM) Dermatophagoides pteronyssinus (Der p) to antigen-presenting cells, with subsequent allergic sensitization. In order to test this hypothesis, we established primary explant cultures of human bronchial epithelial cells (HBEC) in cell culture inserts, and exposed these for 20 min, 1 h, 3 h, and 6 h to CS or air in the absence or presence of 300 ng/ml Der p, and then further incubated the cultures over a period of 24 h. The HBEC cultures were assessed for changes in permeability as measured by changes in: (1) electrical resistance (ER); and (2) passage of 14C-labeled bovine serum albumin (14C-BSA) and Der p allergens across the HBEC cultures. We also assessed the effects of protease inhibitors and the antioxidant glutathione (GSH) in this experimental system. Damage to HBEC cultures was assessed by the release of [51Cr]sodium chromate from prelabeled cells, and by release of lactate dehydrogenase (LDH). Twenty minutes of exposure to CS as compared with exposure to air did not significantly alter either the ER or passage of 14C-BSA across the HBEC cultures. In contrast, incubation with Der p led to a significant increase in the permeability of HBEC cultures, an effect that was enhanced by exposure to CS but was abrogated by the specific protease inhibitors and GSH. Passage of Der p was also increased by exposure to CS. Exposure of HBEC cultures to CS led to a significant release of 51Cr and LDH from these cells as compared with cells exposed to air. This effect was augmented further when HBEC cultures were incubated with Der p. Exposure of HBEC cultures for 1 h, 3 h, and 6 h to CS led to a markedly significant dose- and time-dependent increase in the permeability of these cells. These results suggest that exposure to CS significantly enhances Der p-induced decreases in electrical resistance and the increased passage across HBEC cultures of 14C-BSA and of the Der p allergen itself.

Differences between cytokine release from bronchial epithelial cells of asthmatic patients and non-asthmatic subjects: effect of exposure to diesel exhaust particles.

BACKGROUND: Recent evidence suggests that the airways of asthmatics are more susceptible to adverse effects of air pollutants than the airways of non-asthmatics, but the underlying mechanisms are not clear. METHODS: We have cultured bronchial epithelial cells (HBEC) from biopsies of atopic mild asthmatic patients and non-atopic non-asthmatic subjects, and investigated constitutive and diesel exhaust particles (DEP)-induced release of several pro-inflammatory mediators. RESULTS: HBEC of asthmatic patients constitutively released significantly greater amounts of IL-8, GM-CSF and sICAM-1 than HBEC of non-asthmatic subjects. RANTES was only released by HBEC of asthmatic patients. Incubation of the asthmatic cultures with 10 micrograms/ml DEP significantly increased the release of IL-8, GM-CSF and sICAM-1 after 24 h. In contrast, only the higher concentrations of 50-100 micrograms/ml DEP significantly increased the release of IL-8 and GM-CSF from HBEC of non-asthmatics. CONCLUSIONS: These results suggest that the increased sensitivity of the airways of asthmatics to air pollutants such as DEP may, at least in part, be a consequence of greater constitutive and pollutant-induced release of specific pro-inflammatory mediators from their bronchial epithelial cells.

Effect of fluticasone propionate aqueous nasal spray on allergen-induced inflammatory changes in the nasal airways of allergic rhinitics following exposure to nitrogen dioxide.

BACKGROUND: The authors have recently demonstrated that prior exposure for 6 h to 400 p.p.b. nitrogen dioxide significantly enhances the early phase response of eosinophils in the nasal airways of allergic rhinitics to subsequent allergen provocation. OBJECTIVE: To investigate whether treatment with fluticasone propionate aqueous nasal spray (FP) can alter the inflammatory response in the nasal airways under these conditions. METHODS: Sixteen allergic, rhinitic patients were recruited for this double-blind, randomized, cross-over study and received either topical FP 200 microg once daily or matched placebo for 4 weeks. At the end of treatment, all underwent nasal lavage followed by a 6 h exposure to 400 p.p.b. NO2. Following exposure to NO2, nasal allergen challenge was performed and nasal lavage repeated. After a 4 week washout period, patients were given alternate treatment and tested as above. RESULTS: Analysis of eosinophil cationic protein (ECP) in lavage samples from patients treated with placebo, demonstrated that this was significantly increased from a median value of 2.3 ng/mL (range: 1.0-7.1) to 15.1 ng/mL (range: 1.5-40.0; P = 0.001) following exposure to NO2 and allergen challenge. However, in patients treated with FP, ECP concentrations only increased from 3.3 ng/mL (range: 0.2-9.2) to 5.1 ng/mL (range: 0.3-20.0; P = 0.034) following exposure to NO2 and allergen challenge. The difference of the changes in ECP concentration between the placebo and the FP-treated group was significant (P = 0.003). Similarly, there was a significant increase in the number of eosinophils in nasal lavage after exposure to NO2 and allergen challenge in the placebo group, and this increase was inhibited in FP group (P = 0.002). CONCLUSION: These results suggest that FP influences NO2- and allergen-induced changes in eosinophil function, as well as eosinophil number in the nasal airway of allergic rhinitics.

Involvement of superoxide and nitric oxide on airway inflammation and hyperresponsiveness induced by diesel exhaust particles in mice.

We previously demonstrated that chronic intratracheal instillation of diesel exhaust particles (DEP) induces airway inflammation and hyperresponsiveness in the mouse, and that these effects were partially reversed by the administration of superoxide dismutase (SOD). In the present study, we have investigated the involvement of superoxide in DEP-induced airway response by analyzing the localization and activity of two enzymes: (1) a superoxide producer, NADPH cytochrome P-450 reductase (P-450 reductase), and (2) a superoxide scavenger, SOD, in the lungs of the exposed mice and controls. P-450 reductase was detected mainly in ciliated cells and clara cells: its activity was increased by the repeated intratracheal instillation of DEP. While CuZn-SOD and Mn-SOD were also present in the airway epithelium, their activity was significantly decreased following DEP instillation. Exposure to DEP doubled the level of nitric oxide (NO) in the exhaled air. DEP exposure also increased the level of constitutive NO synthase (cNOS) in the airway epithelium and inducible NO synthase (iNOS) in the macrophages. Pretreatment with N-G-monomethyl L-arginine, a nonspecific inhibitor of NO synthase, significantly reduced the airway hyperresponsiveness induced by DEP. These results indicate that superoxide and NO may each contribute to the airway inflammation and hyperresponsiveness induced by the repeated intratracheal instillation of DEP in mice.

Comparison of ciliary activity and inflammatory mediator release from bronchial epithelial cells of nonatopic nonasthmatic subjects and atopic asthmatic patients and the effect of diesel exhaust particles in vitro.

BACKGROUND: Recent studies have suggested that asthmatic patients may be more susceptible to the adverse effects of air pollutants, including diesel exhaust particles (DEP). The underlying mechanisms, however, are not clear. METHODS: We cultured bronchial epithelial cells from bronchial biopsy specimens of well-characterized groups of nonatopic, nonasthmatic individuals and atopic patients with mild asthma and compared the ciliary beat frequency (CBF) and release of IL-8, GM-CSF, regulated on activation, normal T-cell expressed and secreted (RANTES), and soluble intercellular adhesion molecule-1 (sICAM-1) from these cells both before and after exposure for 24 hours to 10 to 100 micrograms/mL DEP in vitro. RESULTS: The baseline CBF was not found to be significantly different in the bronchial epithelial cell cultures of nonasthmatic and asthmatic individuals. Incubation with DEP significantly attenuated the CBF of both the nonasthmatic and asthmatic bronchial epithelial cell cultures at all concentrations of DEP investigated and were maximal (55.5% and 45.2%, respectively) after incubation with 100 micrograms/mL DEP. The bronchial epithelial cell cultures of asthmatic patients constitutively released significantly greater amounts of IL-8, GM-CSF, and sICAM-1 than bronchial epithelial cell cultures of nonasthmatic subjects. The cultures of only asthmatic patients additionally released RANTES. Incubation of the asthmatic cultures with 10 micrograms/mL DEP significantly increased the release of IL-8 (from 102.0 to 167.8 pg/micrograms cellular protein; P <.01), GM-CSF (from 0.43 to 1.87 pg/micrograms cellular protein; P <.01), and sICAM-1 (from 14.7 to 38.1 pg/micrograms cellular protein; P <.02) after 24 hours. Incubation with 50 to 100 micrograms/mL DEP, however, significantly decreased the release of IL-8 and RANTES from these cultures. In contrast, only the higher concentrations of 50 to 100 micrograms/mL DEP significantly increased release of IL-8 (from 37.9 to 71.5 pg/micrograms cellular protein; P <.05) and GM-CSF (from 0.06 to 0. 34 pg/micrograms cellular protein; P <.05) from the bronchial epithelial cells of nonasthmatic individuals. CONCLUSIONS: These results suggest that bronchial epithelial cells of asthmatic subjects are different from bronchial epithelial cells of nonasthmatic subjects with regard to the amounts and types of proinflammatory mediators they can release and that the increased sensitivity of bronchial epithelial cells of asthmatic subjects to DEP may possibly result in exacerbation of their disease symptoms.

The effect of diesel exhaust particles on cell function and release of inflammatory mediators from human bronchial epithelial cells in vitro.

Animal studies have reported that diesel exhaust particles (DEP), which constitute an important fraction of particulate air pollution, lead to inflammation and/or damage of the airways. To investigate the mechanisms underlying DEP-induced airway disease in humans, we have cultured human bronchial epithelial cells (HBEC) from surgically obtained bronchial explants and investigated the effects of purified DEP on the permeability and ciliary beat frequency (CBF) of HBEC, and on the release of inflammatory mediators from these cells. Exposure to 10-100 microg/ml DEP and a filtered solution of 50 microg/ml DEP significantly increased the electrical resistance of the cultures, reaching a maximum of 200% over baseline after 6 h incubation with 100 microg/ml DEP. In contrast, movement of 14C-labeled bovine serum albumin across cell cultures was not significantly altered by incubation of HBEC with DEP. Exposure to 50 microg/ml DEP, filtered DEP solution, and 100 migrog/ml DEP significantly attenuated the CBF of these cells by 51%, 33%, and 73%, respectively, from baseline after 24 h incubation. Similarly, 50 microg/ml DEP, filtered DEP solution, and 100 microg/ml DEP significantly increased the release of interleukin-8 from 12.9 pg/microg cellular protein to 41.6, 114.9, and 44.3 pg/microg cellular protein, respectively, after 24 h incubation. The release of granulocyte-macrophage colony stimulating factor (GM-CSF) and soluble intercellular adhesion molecule-1 (sICAM-1) was also significantly increased after exposure for 24 h to 50 microg/ml DEP (GM-CSF from 0.033 pg/microg cellular protein to 0.056 pg/mug cellular protein and sICAM-1 from 7.2 pg/microg cellular protein to 12.5 pg/microg cellular protein). These results suggest that exposure of HBEC to DEP may lead to adverse functional changes and release of proinflammatory mediators from these cells, and that these effects may influence the development of airway disease.

Effect of fexofenadine on eosinophil-induced changes in epithelial permeability and cytokine release from nasal epithelial cells of patients with seasonal allergic rhinitis.

Recent studies have suggested that antihistamines, widely used in the treatment of symptoms of patients with allergic rhinitis, may also possess antiinflammatory properties. The mechanisms underlying this property, however, are not clearly understood. We have cultured epithelial cells from nasal biopsy specimens from patients with seasonal allergic rhinitis outside the pollen season and studied the effect of 0 to 10(-3) mol/L fexofenadine, the main active metabolite of terfenadine, on eosinophil-induced changes in electrical resistance (measure of permeability) and release of proinflammatory mediators from these cells. Additionally, we have studied the effect of this drug on eosinophil chemotaxis and adherence to endothelial cells induced by conditioned medium from these human nasal epithelial cell (HNEC) cultures. Incubation of HNEC in the presence of eosinophils treated with opsonized latex beads significantly decreased the electrical resistance of these cultures, an effect that was abrogated by treatment of the cultures with 10(-9) to 10(-3) mol/L fexofenadine. Similarly, incubation of HNEC in the presence of eosinophils treated with latex beads also significantly increased the basal release of the chemokine "regulated upon activation, normal T cell expressed and secreted" (RANTES) (from 96.0 to 613.0 fg/microg cellular protein; p < 0.05), IL-8 (from 42.0 to 198.5 pg/microg cellular protein; p < 0.05), granulocyte-macrophage colony-stimulating factor (GM-CSF) (from 0.54 to 3.4 pg/microg cellular protein; p < 0.05), and soluble intercellular adhesion molecule-1 (sICAM-1) (from 7.8 to 18.4 pg/microg cellular protein; p < 0.05) from HNEC. The eosinophil-induced release of IL-8, GM-CSF, and sICAM-1 from the HNEC was significantly attenuated by treatment with fexofenadine. Analysis of the effects of conditioned medium from HNEC demonstrated that this significantly increased both eosinophil chemotaxis and adherence to endothelial cells. Addition of 10(-6) to 10(-3) mol/L fexofenadine to the conditioned medium significantly attenuated eosinophil chemotaxis and adherence to endothelial cells. These results suggest that fexofenadine may reduce nasal inflammation by modulating the release of proinflammatory mediators and adhesion molecules from HNEC.