Robert J. Davies

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.

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.

BACKGROUNDnRecent 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.nnnMETHODSnWe 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.nnnRESULTSnThe 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.nnnCONCLUSIONSnThese 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 inhaled beclomethasone dipropionate on expression of proinflammatory cytokines and activated eosinophils in the bronchial epithelium of patients with mild asthma

Increasing evidence suggests that cytokines play a role in airway inflammation by attracting and activating inflammatory cells. This may lead to epithelial cell damage and airway hyperresponsiveness. Bronchial provocative concentration of histamine causing a 20% fall in forced expiratory volume in 1 second was measured in patients with mild asthma, and bronchial biopsy specimens were stained for granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-8, and activated eosinophils (EG2) in the bronchial epithelium. The effect of inhaled beclomethasone dipropionate was also assessed in a placebo-controlled double-blind manner. There was a correlation between GM-CSF expression and EG2-staining cells (r = 0.484 p < 0.05) in the epithelium. Provocative concentration of histamine causing a 20% fall in forced expiratory volume in 1 second was correlated with GM-CSF expression (r = -0.462, p < 0.05). Treatment with inhaled beclomethasone dipropionate 500 micrograms twice a day led to a significant decrease in both the expression of GM-CSF (p < 0.01) and IL-8 (p < 0.02) and the number of EG2-staining cells (p < 0.01) in the epithelium. The changes in GM-CSF (r = 0.798, p < 0.01) and IL-8 (r = 0.653, p < 0.02) expression were correlated with the changes in EG2-staining cells after treatment. These results suggest that GM-CSF may influence eosinophil activation in the epithelium in vivo and participate in the etiology of bronchial hyperresponsiveness in mild asthma. Also, beclomethasone dipropionate may inhibit eosinophil activation partly by downregulating the expression of GM-CSF and IL-8 in the bronchial epithelium.

Effect of six-hour exposure to nitrogen dioxide on early-phase nasal response to allergen challenge in patients with a history of seasonal allergic rhinitis

BACKGROUNDnRecent studies have suggested that exposure to air pollutants may enhance the airway responsiveness of susceptible individuals to inhaled allergen.nnnMETHODSnTo investigate the effect of exposure to nitrogen dioxide (NO2) on nasal airways resistance (NAR) and inflammatory mediators in nasal lavage fluid, eight subjects with a history of seasonal allergic rhinitis, who were tested out of season, were exposed in a randomized single-blind, crossover study to either air or 400 ppb NO2 for 6 hours. The changes in NAR and eosinophil cationic protein (ECP), mast cell tryptase (MCT), neutrophil myeloperoxidase (MPO), and interleukin-8 (IL-8) in nasal lavage fluid before and after exposure were evaluated. Another group of eight subjects with a history of seasonal allergic rhinitis were also randomized to exposure to air or 400 ppb NO2 for 6 hours and then challenged with allergen, before evaluation for changes in NAR and changes in ECP, MCT, MPO, and IL-8 in nasal lavage fluid.nnnRESULTSnExposure to air or NO2 did not alter either NAR or the levels of ECP, MCT, MPO, or IL-8 in nasal lavage fluid. Allergen challenge after exposure to both air and NO2 significantly (p < 0.05) increased levels of MCT, but not MPO and IL-8 in the nasal lavage fluid. In addition, allergen challenge after exposure to NO2 but not air, significantly increased levels of only ECP in nasal lavage fluid (p < 0.05).nnnCONCLUSIONSnThese results suggest that acute exposure to NO2 at concentrations found at the curbside in heavy traffic during episodes of pollution, may prime eosinophils for subsequent activation by allergen in individuals with a history of seasonal allergic rhinitis.

A comparison of cytokine release from epithelial cells cultured from nasal biopsy specimens of atopic patients with and without rhinitis and nonatopic subjects without rhinitis

BACKGROUNDnRecent studies have suggested that airway epithelial cells of atopic and nonatopic individuals may differ in their ability to produce proinflammatory cytokines.nnnMETHODSnWe have cultured human nasal epithelial cells (NECs) as confluent explant cultures from nasal biopsy specimens of well-characterized nonatopic normal volunteers without rhinitis (n = 8), atopic volunteers without rhinitis (n = 9), and atopic patient volunteers with rhinitis (n = 10) and measured the amounts of IL-1 beta, IL-8, granulocyte-macrophage colony-stimulating factor, tumor necrosis factor-alpha, and RANTES released spontaneously into the culture medium by these cells in vitro. NECs from patients with allergic rhinitis were cultured from biopsy specimens obtained on two different occasions, during and after the pollen season.nnnRESULTSnIn general, NECs from atopic individuals released significantly greater amounts of IL-1 beta, IL-8, granulocyte-macrophage colony-stimulating factor, tumor necrosis factor-alpha, and RANTES than NECs from nonatopic individuals. IL-8 was released in greatest quantity and IL-1 beta in lowest quantity, regardless of whether the NECs were derived from atopic or nonatopic volunteers. Of the atopic individuals, NECs of atopic patients with rhinitis naturally exposed to pollen released greater quantities of all these cytokines, compared with NECs of atopic patients with rhinitis and atopic patients without rhinitis who were not exposed to allergen.nnnCONCLUSIONSnThese results suggest that NECs of atopic individuals, who are genetically predisposed to upper airway disease, release increased amounts of proinflammatory cytokines and that natural exposure to allergen enhances the release of these cytokines, exacerbating the symptoms of allergic disease.

Lymphocyte infiltration and thickness of the nasal mucous membrane in perennial and seasonal allergic rhinitis

We have used immunocytochemical techniques to study infiltration by lymphocytes in biopsy specimens of the nasal mucosal membrane in 24 atopic patients and 10 normal volunteers. Twelve patients had perennial rhinitis and 12 had seasonal allergic rhinitis (SR) to grass pollen. Biopsy specimens were taken both in and out of the pollen season in patients with SR. Biopsy specimens were strained with the indirect immunoperoxidase technique and monoclonal antibodies to CD3, CD4, CD8, CD22, and CD25. T helper cells (CD4+) and CD24+ cells were significantly more numerous in patients exposed to allergen (those with perennial rhinitis and SR in season) compared with normal volunteers, whereas values for SR out of season were intermediate. The thickness of the nasal epithelium was significantly (p < 0.05) greater in biopsy specimens from patients with perennial rhinitis (mean, 51.43 microns) than in those from patients with SR in season (median, 32.44 microns). These results suggest that in allergic rhinitis, natural exposure to allergen is accompanied by increased infiltration of the nasal mucous membrane by T-helper and CD25+ cells.

The expression of intercellular adhesion molecule-1 and the beta 1-integrins in asthma

Expression of intercellular adhesion molecule-1 (ICAM-1) appears to be important to the development of bronchial hyperresponsiveness and eosinophilia in Ascaris sensitized monkeys. Beta 1-integrins are expressed on epithelial cells, and may contribute to adherence of epithelial cells to the basement membrane. The aim of this study was to determine whether adhesion receptor expression was altered in human asthmatic bronchial epithelium. Using monoclonal antibody staining, we have examined the expression of ICAM-1 and the alpha 1-alpha 6-subunits of the beta 1-integrin family in bronchial mucosal biopsies from 33 asthmatic and 13 nonasthmatic subjects. The epithelium was positive for ICAM-1 in 26 out of 33 asthmatics, although negative in all 13 nonasthmatics. ICAM-1 expression was not associated with bronchial responsiveness or with medication requirements. Beta 1-integrin staining showed that alpha 2-, alpha 3- and alpha 6-subunits stained the epithelium in all cases. Alpha 4 staining was weakly positive in the epithelium in five asthmatics. Alpha 5 staining was weak in asthmatics and normals. Alpha 4 and alpha 6-subunits also stained inflammatory cells. Epithelial upregulation of ICAM-1 is present in asthma. Beta 1-integrins with alpha 2-, alpha 3- and alpha 6-subunits appear to be constitutively expressed in bronchial epithelium.

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.

Occupational asthma caused by low molecular weight chemical agents

Industrial lung diseases have been recognized for many cenruries, but the occurrence of occupational asthma has received attention only in the last five or six decade:s. During this time the increasing importance, complexity, and diversity of industrial processes have greatly multiplied both the number and nature of materials encountered at the work place. One of the earliest reports of occupational asthma described its occurrence in people exposed to the dried residue of the castor bean.’ Since that time many other organic dusts have been incriminated as causes of asthma in industry. These include, among others, dusts from the green coffee bean,* the enzymes of Bacillus subtilis in the detergent industry,3 and papain from the plant Carica papaya.4 In these cases there is little doubt that allergic mechanisms are involved since affected individuals show positive intradermal or prick tests to dust extracts and have specific serum IgE antibodies to the high molecular weight protein antigens. Further, in the detergent industry, asthma occurs more frequently among atopic employees,5 adding further support for the involvement of IgE-mediated type I allergic mechanisms. In 1945, occupational asthma due to simple inorganic chemicals was reported in a comprehensive study which revealed a high frequency of this disease among workers in metal refineries handling the com-

10 – Epithelial Cells

Publisher Summary nThis chapter discusses the morphology of the airway epithelium. Ciliated cells, the predominant cell type in the airway epithelium, are characterized by electron-lucent cytoplasm and are responsible for propelling the tracheobronchial secretion toward the pharynx. The presence of the basal cells contributes to the pseudostratified appearance of the epithelium in the large bronchi and trachea and is thought to play a role in the attachment of superficial cells to the airway basement membrane. The chapter discusses several possible mechanisms that explain the ways epithelial abnormalities can lead to increased bronchial reactivity, including (1) increased permeability to allergen, (2) changes in osmolarity of the bronchial surface lining fluid, (3) exposure of sensory nerve fibers to irritants and potentiation of local axon reflexes, (4) increased production of inflammatory mediators and reduction of putative protective mediators, and (5) modulation of the immune system. The chapter also presents several epithelial cell–derived mediators, including nitric oxide (NO), endothelin, lipid mediators, and cytokines.