Comparative ovicidal activity of Moringa oleifera leaf extracts on Fasciola gigantica eggs.

BACKGROUND: Fasciolosis is an important zoonotic disease affecting the productive performance of farm animals in Egypt. AIM: The aim of the present study was comparing the ovicidal effect of different extracts as an alcoholic (Methanolic and Ethanolic) and aqueous Moringa oleifera leaf extracts on Fasciola gigantica non-embryonated and developed eggs. MATERIALS AND METHODS: Tested concentrations of extracts ranged from 12.5 to 800 mg/ml. Nitroxynil was used as reference drug with a dose of 100 mg/ml. RESULTS: M. oleifera alcoholic and aqueous extracts showed a concentration-dependent ovicidal effect on F. gigantica non-embryonated and developed eggs. Based on LC50 values, water extract showed the highest ovicidal activity since it registered the lowest values of 2.6 mg/ml on non-embryonated eggs. Non-embryonated eggs were more susceptible to aqueous extract than developed eggs. On the other hand, the developed eggs were more susceptible to ethanolic extract than non-embryonated eggs even the lowest LC50 (12.38 mg/ml). CONCLUSION: M. oleifera leaf extracts especially aqueous extract could be a promising step in the field of controlling fascioliasis. Further, in vivo studies are needed to enlighten the therapeutic potential of M. oleifera extracts in treating F. gigantica infection.

The presence of atypical mycobacteria in the mouthwashes of normal subjects: role of tap water and oral hygiene.

BACKGROUND: The nontuberculous mycobacteria (NTM) have been found in different environmental sources. They tend to colonize different body surfaces and secretions. The purpose of this study is to evaluate the presence of NTM in the oral cavity of healthy individuals and its relationship to tap water or oral hygiene. MATERIALS AND METHODS: One hundred sixty-seven healthy subjects were recruited. Three consecutive early morning mouthwashes using tap water were performed and examined for the presence of Mycobacterium tuberculosis (MTB) and NTM. In addition we obtained mouthwashes from 30 control healthy individuals with good oral hygiene using sterile water and examined these for the presence of MTB and NTM. RESULTS: NTM was isolated from the mouthwash of 44 (26.3%) subjects that used tap water. On the other hand, NTM was isolated from the mouthwash of 10 (33%) subjects that used sterile water. Age, gender, social class oral hygiene and the regular use of toothbrush made no statistically significant differences in the isolation rate of NTM. CONCLUSION: The rate of isolation of NTM from mouthwash is high in normal subjects. It is independent of oral hygiene, the use of tap water or teeth brushing. Smear-positive sputum could be NTM rather than M. tuberculosis. Tuberculosis polymerase chain reaction or culture confirmation is essential in developing countries to avoid the unnecessary use of antituberculosis therapy when the clinical suspicion is very low.

Intratracheal cocaine induced myocardial infarction: an unusual complication of fibreoptic bronchoscopy.

A 73 year old man developed chest pains 5 minutes after fibreoptic bronchoscopy. The procedure had been performed without sedation following an intratracheal injection of 5 ml 2.5% cocaine solution and xylocaine spray to the pharynx for topical anaesthesia. A 12-lead electrocardiogram showed an evolving anterior myocardial infarction. Cardiac catheterisation revealed coronary artery spasm in the proximal left anterior descending artery at the site of non-significant plaque disease. The risk factors, mechanisms, and treatment of cocaine induced myocardial infarction following intratracheal injections are discussed.

Effect of ozone and nitrogen dioxide on the permeability of bronchial epithelial cell cultures of non-asthmatic and asthmatic subjects.

BACKGROUND: Although epidemiological as well as in vivo exposure studies suggest that ozone (O3) and nitrogen dioxide (NO2) may play a role in airway diseases such as asthma, the underlying mechanisms are not clear. OBJECTIVE: Our aim was to investigate the effect of O3 and NO2 on the permeability of human bronchial epithelial cell (HBEC) cultures obtained from non-atopic non-asthmatic (non-asthmatics) and atopic mild asthmatic (asthmatics) individuals. METHODS: We cultured HBECs from bronchial biopsies of non-asthmatics and asthmatics, and exposed these for 6 h to air, 10 to 100 parts per billion (p.p.b.) O3, or to 100 to 400 p.p.b. NO2, and assessed changes in electrical resistance (ER) and movement of 14C-BSA across the cell cultures. RESULTS: Although exposure to either O3 or NO2 did not alter the permeability of HBEC cultures of non-asthmatics, 10 to 100 p.p.b. O3 and 400 p.p.b. NO2 significantly decreased the ER of HBEC cultures of asthmatics, when compared with exposure to air. Additionally, 10, 50 and 100 p.p.b. O3 led to a significant increase in the movement of 14C-BSA across asthmatic HBEC cultures, after 6 h of exposure (medians = 1.73%; P < 0.01, 1.50%; P < 0.05 and 1.53%, P < 0.05, respectively), compared with air exposed cultures (median = 0.89%). Similarly, exposure for 6 h to both 200 and 400 p.p.b. NO2 significantly increased the movement of 14C-BSA across asthmatic HBEC cultures, when compared with air exposure. A comparison of data obtained from the two study groups demonstrated that 10 to 100 p.p.b. O3- and 200 to 400 p.p.b. NO2-induced epithelial permeability was greater in cultures of asthmatics compared with non-asthmatics. CONCLUSION: These results suggest that HBECs of asthmatics may be more susceptible to the deleterious effects of these pollutants. Whether in patients with asthma the greater susceptibility of bronchial epithelial cells to O3 and NO2 contributes to the development of the disease, or is a secondary characteristic of this condition, remains to be determined.

Effect of ozone and nitrogen dioxide on the release of proinflammatory mediators from bronchial epithelial cells of nonatopic nonasthmatic subjects and atopic asthmatic patients in vitro.

BACKGROUND: Although studies have suggested that ozone (O3) and nitrogen dioxide (NO2) may play a role in the pathogenesis of asthma, the underlying mechanisms are not clear. OBJECTIVE: We aimed to investigate the effects of O3 and NO2 on the release of IL-8, GM-CSF, RANTES, and soluble intercellular adhesion molecule 1 (sICAM-1) from human bronchial epithelial cells (HBECs) of nonatopic nonasthmatic subjects (nonasthmatic subjects) and atopic subjects with mild asthma (asthmatic subjects) in vitro. METHODS: We cultured HBECs from bronchial biopsy specimens of nonasthmatic and asthmatic subjects; exposed these for 6 hours to air, 10 to 100 ppb O3, or 100 to 400 ppb NO2; and analyzed the release of IL-8, GM-CSF, RANTES, and sICAM-1 after 24 hours' incubation. RESULTS: There was no significant difference between the constitutive release of IL-8, GM-CSF, and sICAM-1 from HBECs of asthmatic and nonasthmatic subjects. RANTES was detected only in HBECs derived from asthmatic subjects. Exposure of HBECs of asthmatic subjects to both 50 to 100 ppb O3 and 200 to 400 ppb NO2 significantly increased the release of IL-8, GM-CSF, RANTES, and sICAM-1 from these cells after 24 hours of incubation. However, 50 to 100 ppb O3 and 200 to 400 ppb NO2 led to a significant increase in release of only IL-8 and sICAM-1 from HBECs of nonasthmatic subjects after 24 hours' incubation. A comparison between the pollutant-induced release of mediators demonstrated that 100 ppb O3-induced release of GM-CSF and sICAM-1 was significantly greater in HBECs of asthmatic subjects (medians, 0.59 and 27.4 pg/microg cellular protein, respectively) than in HBECs of nonasthmatic subjects (medians, 0.27 and 14.4 pg/microg cellular protein, respectively; P < .02). CONCLUSION: These results suggest that O3 and NO2 may modulate airway diseases, such as asthma, by increasing the release of inflammatory mediators from bronchial epithelial cells and that the cells of asthmatic subjects may be more susceptible to the adverse effects of these pollutants.

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.

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.

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.

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.

The effect of nedocromil sodium on human airway epithelial cell-induced eosinophil chemotaxis and adherence to human endothelial cell in vitro.

Although some studies have shown that long-term treatment of asthmatics with nedocromil sodium can reduce airway hyperresponsiveness and improve symptoms and lung function, the mechanisms underlying its effects are not well understood. We have investigated the effect of nedocromil sodium on eosinophil chemotaxis, eosinophil adherence to human endothelial cells and release of soluble intercellular adhesion molecule-1 (sICAM-1) from endothelial cells, induced by conditioned medium collected from cultured human bronchial epithelial cells. Conditioned medium significantly increased eosinophil chemotaxis from a baseline median value of 2.1 (range 1.9-4.5) cells-high power field(-1) (HPF) to 10.5 (range 7.8-12.3) cells-HPF(-1) (p<0.05). Similarly, conditioned medium significantly increased eosinophil adherence to endothelial cells from a baseline value of 9 (range 8-12)% to 23 (range 21-30)% (p<0.05). Nedocromil sodium, at 10(-5) M concentration, significantly attenuated the eosinophil chemotaxis and adherence induced by conditioned medium. Conditioned medium also significantly increased the release of sICAM-1 from endothelial cells, from a baseline value of 11.5 (range 8.1-15.4) pg x microg(-1) protein to 67.6 (range 55.6-73.5) pg x microg(-1) protein (p<0.05). This was significantly attenuated by anti-tumour necrosis factor-alpha (TNF-alpha), anti-interleukin-1beta (IL-1beta) and 10(-5) M nedocromil sodium. These findings suggest that human bronchial epithelial cell-derived mediators may potentiate eosinophil activity, and that this can be modulated by nedocromil sodium, suggesting a possible mechanism underlying its anti-inflammatory effect.

New insights into the understanding of asthma.

The prevalence of asthma is increasing, despite better understanding of its pathogenesis and improved treatments. During the past 10 years, the perception of asthma has shifted from a disease primarily characterized by altered smooth muscle function to one mainly characterized by chronic inflammation. This article reviews the evidence supporting the relationship of inflammation in both the upper and lower airways, focusing on intermittent seasonal disease as well as on the more chronic and severe forms of asthma, including that associated with aspirin intolerance. It also presents evidence to support a pivotal role for the epithelial cell, together with the mast cell and the eosinophil, in initiating and maintaining inflammation in the upper and lower airways.

Allergen-irritant interaction and the role of corticosteroids.

Studies of exposure to air pollutants, such as ozone and nitrogen dioxide (NO2) +/- sulphur dioxide (SO2), have demonstrated that these agents, either individually or in combination, increase the airway response of both asthmatics and allergic rhinitics to inhaled allergen. Other studies have demonstrated that exposure to these pollutants significantly increased the levels of eosinophil cationic protein (ECP) in the nasal secretions of both asthmatics and allergic rhinitics, suggesting that pollutants may prime eosinophils for subsequent activation by allergen. More recently, our studies have demonstrated that treatment with inhaled corticosteroids, such as fluticasone propionate, significantly attenuated pollution+ allergen-induced release of ECP in allergic rhinitics. Although the mechanisms underlying the potentiating effects of pollutants on allergen-induced changes in the airways of allergic individuals are not fully understood, in vitro studies have suggested that airway epithelial cells may play an important role, since they can synthesize a variety of cytokines and adhesion molecules which influence the activity of eosinophils and other inflammatory cells. Studies of nasal epithelial cells cultured from biopsies of atopic rhinitic and atopic non-rhinitic individuals have shown that they constitutively release significantly greater quantities of pro-inflammatory cytokines than nasal epithelial cells of non-atopic individuals, and that the release of these cytokines is greater from cells of atopic rhinitics during the pollen season. Furthermore, exposure of the cells of rhinitics to ozone led to an even greater release of these cytokines, and this effect was attenuated by treatment with fluticasone propionate and beclomethasone dipropionate.

Nedocromil sodium and airway inflammation in vivo and in vitro.

We conducted a series of studies investigating the antiinflammatory effects of nedocromil sodium, with particular reference to its effects on human bronchial epithelial cells and eosinophils in vitro and on eosinophils in vivo. Nedocromil sodium produced a dose-related inhibition of ozone-induced IL-8 release from human bronchial epithelial cells and also attenuated the release of granulocyte macrophage colony-stimulating factor, tumor necrosis factor-alpha, and soluble intercellular adhesion molecule 1. The culture medium from human bronchial epithelial cell cultures, containing the proinflammatory cytokines IL-8, granulocyte macrophage colony-stimulating factor, "regulated on activation, normal T expressed and secreted," IL-1 beta, and tumor necrosis factor-alpha, increased eosinophil chemotaxis and eosinophil adhesion to cultured human endothelial cells. The chemotaxis and increased adhesion were blocked in the presence of nedocromil sodium. The drug also abrogated the epithelial cell dysfunction (assessed as ciliary beat frequency) induced by the presence of activated eosinophils and blocked the release of eosinophil cationic protein from the eosinophils. We also conducted a double-blind placebo-controlled study of the effects of regular albuterol 200 micrograms or nedocromil sodium 4 mg, both given four times daily for 16 weeks, on inflammatory cell numbers in bronchial biopsy and bronchoalveolar lavage samples. Assessed in terms of total and activated eosinophils in biopsy samples, inflammation decreased with nedocromil sodium and was significantly different from a deterioration with albuterol, although neither of these changes was significantly different from that with placebo treatment. Levels of eosinophil cationic protein in bronchoalveolar lavage samples showed a similar trend.

Air pollutants and respiratory hypersensitivity.

Epidemiological evidence suggests that an increase in liquid petroleum derived pollutants is associated with exacerbation of allergic airway disease, and that the effects of pollution may occur 1-2 days later. Laboratory based studies have demonstrated that the pollutants responsible for the adverse effects on respiratory health include nitrogen dioxide (NO2), sulphur dioxide (SO2), ozone (O3) and respirable particulates (PM10). More recently, studies of asthmatic individuals exposed to O3, NO2 and a combination of NO2 and SO2 have indicated that these agents increase the airway responsiveness of these individuals to inhaled allergen, and that this effect may be maximal 24 h after exposure to the pollutants. Studies investigating the putative mechanisms underlying the effects of these pollutants suggest that exposure to these agents may lead to perturbation of the airway epithelium and release of pro-inflammatory mediators from the epithelial cells, which then influence the activity of inflammatory cells, such as eosinophils.

The effect of conditioned medium from cultured human bronchial epithelial cells on eosinophil and neutrophil chemotaxis and adherence in vitro.

Several studies have demonstrated that bronchial epithelial cells are capable of synthesizing proinflammatory cytokines that may influence eosinophil and neutrophil activity. We have cultured human bronchial epithelial cells to confluence, as explant cultures, and investigated the effect of conditioned medium from these cells on (1) the chemotaxis of eosinophils and neutrophils and (2) the adherence of these cells to cultured human endothelial cells. Analysis of cytokines, namely interleukin-1 beta (IL-1 beta), interleukin-8 (IL-8), tumor necrosis factor alpha (TNF alpha), granulocyte/macrophage colony-stimulating factor (GM-CSF), and RANTES, which are thought to be involved in these processes, demonstrated that all these cytokines were synthesized and released constitutively from the bronchial epithelial cell cultures. Conditioned medium obtained after 24 h of incubation significantly increased the chemotaxis of eosinophils and neutrophils, from median values of 4.0 cells/per high power field (hpf) (range, 3.0 to 7.0) and 17 cells/hpf (range, 13.0 to 25.0), respectively, for medium 199, to median values of 11.0 cells/hpf (range, 9 to 12; P = 0.005) and 30 cells/hpf (range, 19 to 33; p = 0.01). Whereas anti-GM-CSF and anti-IL-8 neutralizing monoclonal antibodies significantly attenuated the conditioned medium-induced chemotaxis of eosinophils and neutrophils, anti-RANTES neutralizing antibody significantly attenuated the chemotaxis of only eosinophils. Conditioned medium also significantly increased the percentage of eosinophils and neutrophils adhering to endothelial cells in a dose-dependent manner. Both anti-human TNF alpha and anti-human IL-1 beta neutralizing antibodies significantly attenuated the conditioned medium-induced adherence of eosinophils and neutrophils to the endothelial cells and were found to have an additive effect when studied together. Similarly, treatment of endothelial cells with either anti-ICAM-1 or anti-E-selectin, for 1 h before co-culture with eosinophils and neutrophils, significantly attenuated the conditioned medium-induced adherence of both eosinophils and neutrophils to endothelial cells. Treatment of endothelial cells with anti-VCAM-1 attenuated the adherence of eosinophils but not neutrophils. These results suggest that human bronchial epithelial cells, through their ability to generate proinflammatory mediators, are likely to play a role in the pathogenesis of airway disease by influencing chemotaxis and adherence of eosinophils and neutrophils.

Effect of erythromycin on Haemophilus influenzae endotoxin-induced release of IL-6, IL-8 and sICAM-1 by cultured human bronchial epithelial cells.

Although several studies have demonstrated that low-dose, long-term erythromycin treatment is effective in the management of patients with chronic lower respiratory tract infections, such as chronic bronchitis, bronchiolitis and bronchiectasis, the mechanisms underlying the action of erythromycin are not clear. We have cultured human bronchial epithelial cells (HBEC) as explant cultures from surgical tissue, and have investigated the effect of erythromycin on H. influenzae endotoxin (HIE)-induced release of inflammatory mediators in these cultures. Confluent epithelial cell cultures were incubated with 100 micrograms.mL-1 HIE +/- 0.1-10 micrograms.mL-1 erythromycin and were investigated for interleukin-6 (IL-6), interleukin-8 (IL-8) and soluble intercellular adhesion molecule-1 (sICAM-1) released into the culture medium after 24 h. HIE significantly increased the release of IL-6 from 3.9 +/- 1.5 pg.micrograms-1 cellular protein (in control untreated cultures) to 12.1 +/- 1.5 pg.micrograms-1 cellular protein, and IL-8 from 83.7 +/- 8.2 pg.micrograms-1 cellular protein (in control cultures) to 225.7 +/- 44.8 pg.micrograms-1 cellular protein. Similarly, HIE led to a significantly greater release of sICAM-1 from 0.04 +/- 0.01 ng.microgram-1 cellular protein, in control cultures, to 3.8 +/- 0.9 ng.microgram-1 cellular protein. Incubation of the epithelial cultures in the presence of 0.1-10 micrograms.mL-1 erythromycin significantly blocked the HIE-induced release of IL-6, IL-8, and sICAM-1, at all concentrations of erythromycin investigated. Erythromycin also attenuated neutrophil chemotaxis and adhesion to human endothelial cells, mediated by incubation with conditioned medium obtained from HIE-exposed epithelial cell cultures, in vitro. These results suggest that H. influenzae-induced release of inflammatory mediators from airway epithelial cells could contribute to chronic airway inflammation, and that this effect may be modulated by treatment with erythromycin.

Effect of Haemophilus influenzae endotoxin on the synthesis of IL-6, IL-8, TNF-alpha and expression of ICAM-1 in cultured human bronchial epithelial cells.

Although studies of infective lung diseases have demonstrated that Haemophilus influenzae is a major pathogen, the mechanisms underlying pathogenesis by this organism are not clear. We have cultured human bronchial epithelial cells (HBEC) to confluency and have investigated the effect of H. influenzae endotoxin (HIE) on: 1) epithelial permeability, by movement of 14C-bovine serum albumin (14C-BSA) across HBEC and measurement of electrical resistance of HBEC; 2) release of interleukin-6 (IL-6), interleukin-8 (IL-8) and tumour necrosis factor-alpha (TNF-alpha) into the supernatant, by enzyme-linked immunosorbent assay (ELISA); and 3) expression of intercellular adhesion molecule-1 (ICAM-1), by immunofluorescence staining. HIE did not significantly increase the movement of 14C-BSA across HBEC. In contrast, HIE progressively increased the electrical resistance of HBEC, such that this was significant after 24 h. Compared with untreated cells, 10-100 micrograms.ml-1 HIE-treated cells released significantly greater amounts of IL-6, IL-8 and TNF-alpha, after 24 h, which was blocked by 10(-5) M hydrocortisone. Similarly, incubation of HBEC with 10-100 micrograms.ml-1 HIE, significantly increased the total number of ICAM-1 positive cells, which were significantly decreased on incubation of the cells in the presence 10(-5) M hydrocortisone. Conditioned medium from HIE-exposed HBEC lead to significant increase in neutrophil chemotaxis and adhesion to endothelial cells in vitro. These results suggest that HIE may affect epithelial cell function and influence inflammation of the airway mucosa via induction of proinflammatory mediators.