Activation by histamine of bronchial epithelial cells from nonasthmatic subjects

The effect of H1 antagonists carebastine and olopatadine on histamine induced expression of CC chemokines in cultured human nasal epithelial cells

BACKGROUND

CC chemokines have been shown to play an important role in inducing selective recruitment of inflammatory cells into local allergic inflammatory sites. CC chemokines are also known as histamine releasing factors. We previously showed that histamine enhances transcription of CC chemokines from nasal mucosa which leads to further induction of histamine release. This cyclic cascade may cause prolonged allergic inflammation. The aim of this study is to clarify the relationship between histamine and CC chemokine production by using human nasal epithelial cells (HNECs) and to examine the potential of H1 receptor (H1R) antagonists in new therapeutic approaches for the treatment of nasal allergy.

METHODS

HNECs were isolated from the nasal turbinates of patients diagnosed with nasal allergy. HNEC monolayers were cultured for 48 hours with or without histamine (10(-3) to 10(-5) mol/L). Furthermore, an H1R antagonist, either carebastine or olopatadine, was added to the supernatant (10(-3) to 10(-7) mol/L) 30 minutes before incubation with histamine. The expression of Regulated on Activation, Normal T-cell Expressed and Secreted (RANTES) and monocyte chemotactic protein-1 (MCP-1) in the culture media were measured by ELISA.

RESULTS

The release of RANTES and MCP-1 was significantly upregulated by histamine compared with the control group. Both carebastine and olopatadine inhibited the release of CC chemokine production to the control level in both groups.

CONCLUSIONS

This study suggests that the interaction between histamine and CC chemokines may prolong allergic inflammation in human nasal mucosa. We also demonstrate the potential use of H1R antagonists in new therapeutic approaches to the treatment of nasal allergy through inhibiting this histamine-CC chemokine interaction.

Effects of fexofenadine on T-cell function in a murine model of allergen-induced airway inflammation and hyperresponsiveness

There is renewed interest in antihistamines for the treatment of allergic asthma. A growing body of literature has shown that the newer compounds can affect inflammatory cell accumulation and cytokine/chemokine production. In a murine model of allergen-induced airway inflammation and hyperresponsiveness, the ability of fexofenadine to affect these outcomes was tested in a primary sensitization and challenge model and after treatment of donor mice before the adoptive transfer of T cells into recipients receiving limited allergen exposure. Mice were sensitized and challenged with allergen (ovalbumin). Airway function after inhaled methacholine was monitored in parallel to the assessment of tissue and airway inflammation and cytokine production. In further experiments, lung T lymphocytes from sensitized/challenged donor mice were transferred into naive recipients before limited airway challenge with the allergen. Administration of fexofenadine before challenge but after sensitization was effective in preventing tissue eosinophilia and airway hyperresponsiveness. Moreover, the treatment of donor mice with fexofenadine before transfer of lung T cells effectively prevented airway hyperresponsiveness and eosinophilia in naive mice exposed to limited airway challenge. These data therefore support the potential for fexofenadine in the treatment of allergen-induced airway hyperresponsiveness and inflammation.

H1-receptors: localization and role in airway physiology and in immune functions

Histamine H(1)-receptors are involved in the pathologic processes of allergy. Clinical trials of H(1)-receptor antagonists have demonstrated the efficacy of these agents in reducing the sneezing, pruritus, and rhinorrhea associated with allergic rhinitis. In the lung, H(1)-receptors mediate the bronchoconstrictive effects of histamine and increase vascular permeability, which lead to plasma exudation. H(1)-receptors are present on T cells, B cells, monocytes, and lymphocytes, and stimulation of these receptors induces pro-inflammatory effects. It has been suggested that a signal from the H(1)-receptor contributes to the antigen receptor-mediated signaling pathways that induce proliferative responses and lead to the production of cytokines and antibodies by T cells and B cells, respectively. It would appear, therefore, that the H(1)-receptor has a wider role in inflammatory processes than simply mediating the actions of histamine.

Effect of cilomilast (Ariflo) on TNF-alpha, IL-8, and GM-CSF release by airway cells of patients with COPD

BACKGROUND

Inflammation in chronic obstructive pulmonary disease (COPD) is characterised by increased neutrophilic infiltration of the airways. Cilomilast, a novel selective phosphodiesterase 4 inhibitor in clinical development for COPD treatment, exerts anti-inflammatory effects. The ability of cilomilast to inhibit the release of neutrophil chemoattractants such as tumour necrosis factor (TNF)-alpha, interleukin (IL)-8, and granulocyte-macrophage colony stimulating factor (GM-CSF) by bronchial epithelial cells and sputum cells isolated from 10 patients with COPD, 14 normal controls, and 10 smokers was investigated.

METHODS

Bronchial epithelial cells obtained by bronchial brushing and sputum cells isolated from induced sputum samples were cultured for 24 hours in the presence or absence of cilomilast (1 micro M). After incubation the supernatants were harvested and the levels of mediators measured by ELISA. Chemotactic activity in supernatants was also measured using a Boyden chamber.

RESULTS

TNF-alpha and IL-8 release by bronchial epithelial cells and sputum cells was higher in patients with COPD than in controls (p<0.0001) and smokers (p<0.0001). GM-CSF was only detectable in sputum cell supernatants and its level was higher in patients with COPD than in controls and smokers (p<0.0001, respectively). Cilomilast significantly reduced TNF-alpha release by bronchial epithelial cells and sputum cells (p=0.005) and GM-CSF release by sputum cells (p=0.003), whereas IL-8 release was not statistically inhibited. Supernatants of sputum cells and bronchial epithelial cells treated with cilomilast significantly decreased neutrophil chemotaxis (p<0.006 and p<0.008, respectively).

CONCLUSIONS

Cilomilast inhibits the production of some neutrophil chemoattractants by airway cells. This drug may play a role in the resolution of neutrophilic inflammation associated with COPD and cigarette smoke.

Safety and cellular assessment of bronchial brushing in airway diseases

Bronchial brushing is a useful method for morphological and functional studies of bronchial epithelial cells (BECs) in various diseases. This technique has been found to be generally safe, but its safety in asthma and chronic bronchitis has not been fully assessed. The purpose of this study was to determine 1, whether bronchial brushing is a safe method in asthmatic and chronic bronchitis patients of differing severity and 2, to characterize the BECs obtained in terms of number, viability and purity. We evaluated 25 asthmatics of variable severity, 19 chronic bronchitis patients and 26 normal volunteers. Bronchoscopy and bronchial brushing were performed in a standardized manner by the same investigator. Safety was assessed by clinical follow-up of all subjects; continuous monitoring of arterial oxygen saturation during the procedure with a digital oximeter was carried out in a subsample of subjects. No complications were observed clinically during the procedure. There was a minimal fall in arterial oxygen saturation without a significant difference between the three groups of subjects. A consistent number of BECs was recovered and their viability, assessed by the trypan blue exclusion test, in asthmatics and chronic bronchitis patients was significantly lower than in controls (P < 0.05). Bronchial brushing is well tolerated and may be a valuable method of obtaining BECs in asthmatic and chronic bronchitis patients.

IL-4 induces ICAM-1 expression in human bronchial epithelial cells and potentiates TNF-alpha

Interleukin (IL)-4 is thought to contribute to the Th2 type of immune response and hence the development of allergic reactions such as asthma. In asthmatic patients, the airway epithelium expresses increased amounts of the cell surface adhesion molecule intercellular adhesion molecule (ICAM)-1 (CD54). One cytokine capable of inducing ICAM-1 in airway epithelial cells, tumor necrosis factor-alpha (TNF-alpha), is present in asthma. This study evaluated if IL-4 either alone or together with TNF-alpha costimulation might modulate CD54 expression by human bronchial epithelial cells (HBECs). CD54 positivity increased in response to IL-4 (16 +/- 2% positive vs. 3 +/- 1%, P < 0.01); greater induction of CD54 resulted from TNF-alpha (45 +/- 2%, P < 0.001). Costimulation with TNF-alpha plus IL-4 further augmented expression (56 +/- 1%, P < 0.05). Immunoperoxidase results were confirmed by flow cytometry. RT-PCR revealed no increase in ICAM-1 mRNA expression under control conditions or after stimulation with IL-4 alone. TNF-alpha increased IL-4 mRNA, and IL-4 potentiated this. Functionally, IL-4 augmented the adhesion of THP-1 monocyte/macrophage cells to monolayers of HBECs both alone and in the presence of TNF-alpha. We conclude that 1) IL-4 augments epithelial cell ICAM-1 expression, 2) IL-4 potentiates the adhesion of THP-1 monocyte/macrophage cells to epithelial cells, and 3) modulation of epithelial cell ICAM-1 expression by IL-4 may play a role in the immunopathology of bronchial asthma.

Segmental antigen challenge increases fibronectin in bronchoalveolar lavage fluid

Fibronectin may contribute to asthma pathogenesis by recruitment and activation of inflammatory cells, and by promotion of subepithelial fibrosis. Fibronectin is produced by several types of airway cells, including epithelial cells, fibroblasts, and alveolar macrophages. To test the hypothesis that antigen-induced airway inflammation is associated with increased local generation of fibronectin, segmental bronchoprovocation (SBP) with antigen and saline was performed in 17 atopic patients. Bronchoalveolar lavage (BAL) was performed at 5 min and 48 h after segmental challenge with saline or antigen. Fibronectin concentrations in BAL fluid, measured by enzyme-linked immunosorbent assay (ELISA), increased more than 5-fold 48 h after antigen challenge (65 [47 to 110] versus 407 [240 to 697] ng/ml, median and 25 to 75% interquartiles, p < 0.05). Fibronectin concentrations 48 h after antigen challenge correlated with histamine concentrations 5 min after antigen challenge and numbers of eosinophils, neutrophils, macrophages, and total cells in BAL fluid 48 h after antigen challenge. BAL was more enriched in fibronectin 48 h after challenge than would be predicted solely from increased permeability of plasma proteins. Western blot analysis showed that fibronectin in BAL fluid was largely intact and contained the extra domain-A (ED-A) splice variant of cellular fibronectin, indicative of local production. We conclude that antigen challenge in atopic subjects causes increased production of fibronectin by airway cells and speculate that this response may contribute to airway remodeling in allergic inflammation.

Fenspiride inhibits histamine-induced responses in a lung epithelial cell line

Using the human lung epithelial WI26VA4 cell line, we investigated the capacity of fenspiride, an anti-inflammatory drug with anti-bronchoconstrictor properties, to interfere with histamine-induced intracellular Ca2+ increase and eicosanoid formation. Histamine and a histamine H1 receptor agonist elicited a rapid and transient intracellular Ca2+ increase (0-60 s) in fluo 3-loaded WI26VA4 cells. This response was antagonized by the histamine H1 receptor antagonist, diphenhydramine, the histamine H2 receptor antagonist, cimetidine, having no effect. Fenspiride (10(-7)-10(-5) M) inhibited the histamine H1 receptor-induced Ca2+ increase. In addition, histamine induced a biphasic increase in arachidonic acid release. The initial rise (0-30 s), a rapid and transient arachidonic acid release, was responsible for the histamine-induced intracellular Ca2+ increase. In the second phase release (15-60 min), a sustained arachidonic acid release appeared to be associated with the formation of cyclooxygenase and lipoxygenase metabolites. Fenspiride (10(-5) M) abolished both phases of histamine-induced arachidonic acid release. These results suggest that anti-inflammatory and antibronchoconstrictor properties of fenspiride may result from the inhibition of these effects of histamine.

Reduction of soluble ICAM-1 levels in nasal secretion by H1-blockers in seasonal allergic rhinitis

ICAM-1, a transmembrane glycoprotein promoting adhesion in immunologic and inflammatory reactions, was found to be increased on nasal epithelial cells of patients with allergic rhinitis. Loratadine, an H1-blocker, was found to reduce in vitro the expression of ICAM-1 on nasal epithelial cells. A double-blind, parallel-group study was carried out during the pollen season to compare the effect of two H1-blockers, cetirizine (10 mg OD) and loratadine (10 mg OD), on the release of soluble ICAM-1 in nasal secretions. A group of untreated patients was used as a control group. sICAM-1 was measured by enzyme immunoassay before and after 2 weeks of treatment. Symptoms were significantly decreased in the actively treated groups. sICAM-1 levels were unchanged in the control group but were significantly reduced in the two treated groups (P < 0.015, Wilcoxon's W test). This study shows that two H1-blockers, loratadine and cetirizine, have a similar effect on sICAM-1 released in nasal secretions during the pollen season.

Binding of Aspergillus fumigatus spores to lung epithelial cells and basement membrane proteins: relevance to the asthmatic lung

BACKGROUND

Aspergillus fumigatus is an opportunistic pathogen to which asthmatic subjects are particularly susceptible. The ability of spores of A fumigatus to bind to pulmonary cells and basement membrane proteins was investigated to determine the mechanisms involved in this susceptibility.

METHODS

Cells of the A549 pulmonary epithelial cell line or purified basement membrane proteins were immobilised on the wells of microtitre plates. They were then exposed to spores of A fumigatus in suspension, with or without various pretreatments of the spores, cells, and proteins. Adherent spores were counted by light microscopy.

RESULTS

Spores of A fumigatus bound in a concentration dependent manner to A549 epithelial cells and pretreatment of cells with interferon gamma (2500 units/ml) caused a significant doubling of spore binding. Binding of spores to A549 cells was inhibited by about a third by pre-incubation of the spores with fibrinogen (100 micrograms/ml). Spores bound specifically to extracellular matrix (ECM) components laid down by A549 cells, and pretreatment of the ECM components with hydrogen peroxide (25-80 microM) enhanced spore binding by approximately one third. They also bound specifically and in a saturable manner to purified fibrinogen, fibronectin, laminin, type I collagen, and type IV collagen. Pre-incubation of spores with Arg-Gly-Asp tripeptide (RGD; 50-200 micrograms/ ml) inhibited binding to fibronectin and type I collagen by 50%.

CONCLUSIONS

This study suggests that the presence of activated epithelial cells and the exposure of basement membrane that occurs in asthma, together with oxidant stress, may facilitate the colonisation of the asthmatic lung by A fumigatus. The RGD sequence may be involved in spore binding to some ECM proteins. Free fibrinogen may protect against binding of A fumigatus spores to the pulmonary epithelium.

Intercellular adhesion molecule-1

The intercellular adhesion molecule (ICAM) 1 is an Ig-like cell adhesion molecule expressed by several cell types, including leukocytes and endothelial cells. It can be induced in a cell-specific manner by several cytokines, for example, tumor necrosis factor-alpha, interleukin-1, and interferon-gamma, and inhibited by glucocorticoids. Its ligands are the membrane-bound integrin receptors LFA-1 and Mac-1 on leukocytes, CD43, the soluble molecule fibrinogen, the matrix factor hyaluronan, rhinoviruses, and Plasmodium falciparum malaria-infected erythrocytes. ICAM-1 expression is predominantly transcriptionally regulated. The ICAM-1 promoter contains several enhancer elements, among them a novel kappa B element which mediates effects of 12-O-tetradecanoylphorbol-13-acetate, interleukin-1, lipopolysaccharide, tumor necrosis factor-alpha, and glucocorticoids. Expression regulation is cell specific and depends on the availability of cytokine/hormone receptors, signal transduction pathways, transcription factors, and posttranscriptional modification. ICAM-1 plays a role in inflammatory processes and in the T-cell mediated host defense system. It functions as a costimulatory molecule on antigen-presenting cells to activate MHC class II restricted T-cells, and on other cell types in association with MHC class I to activate cytotoxic T-cells. ICAM-1 on endothelium plays an important role in migration of (activated) leukocytes to sites of inflammation. ICAM-1 is shed by the cell and detected in plasma as sICAM-1. Regulation and significance of sICAM-1 are as yet unclear, but sICAM-1 is increased in many pathological conditions. ICAM-1 may play a pathogenetic role in rhinovirus infections. Derangement of ICAM-1 expression probably contributes to the clinical manifestations of a variety of diseases, predominantly by interfering with normal immune function. Among these are malignancies (e.g., melanoma and lymphomas), many inflammatory disorders (e.g., asthma and autoimmune disorders), atherosclerosis, ischemia, certain neurological disorders, and allogeneic organ transplantation. Interference with ICAM-1 leukocyte interaction using mAbs, soluble ICAM-1, antisense ICAM-1 RNA, and in the case of melanoma mAb-coupled immunotoxin, may offer therapeutic possibilities in the future. Integration of knowledge concerning membrane-bound and soluble ICAM-1 into a single functional system is likely to contribute to elucidating the immunoregulatory function of ICAM-1 and its pathophysiological significance in various disease entities.

Terfenadine exerts antiallergic activity reducing ICAM-1 expression on nasal epithelial cells in patients with pollen allergy

BACKGROUND

Rhinoconjunctivitis caused by pollen allergy is characterized by typical signs and symptoms and mucosal infiltration by inflammatory cells during the pollen season. It has recently been demonstrated that the adhesion molecule system is deeply involved in cell-to-cell interaction during the inflammatory response which follows allergic reactions.

OBJECTIVE

The aim of the present study (placebo-controlled, double-blind, randomized) was the evaluation of the antiallergic activity of Terfenadine in the model of the allergic rhinitis due to natural pollen exposure.

METHODS

Two groups of patients with pollen allergy were enrolled in this study. Ten patients were treated with Terfenadine (120 mg/die) for 7 days and 10 with placebo. Evaluation criteria were: (a) clinical: signs and symptoms (recorded daily in a diary card by patients); (b) cytological: inflammatory cell count (neutrophils, eosinophils, metachromatic cells) from nasal lavage at T0 and T7; (c) immunocytochemical: ICAM-1/CD54 expression on nasal epithelial cells at T0 and T7; and (d) mediators dosage (ECP-MPO) on nasal lavage at T0 and T7.

RESULTS

As opposed to the placebo group, patients treated with Terfenadine showed a significant improvement of both symptoms (P < 0.022) and signs P < 0.001), a significant reduction of inflammatory cells infiltrate (P < 0.005), of ECP levels (P < 0.002) and ICAM-1 expression on nasal epithelial cells (P < 0.005).

CONCLUSIONS

In conclusion, these data demonstrate that Terfenadine exerts antiallergic activity since it is able to reduce inflammatory cell infiltrate and downregulates ICAM-1 expression.

Inhibitory activity of loratadine and descarboethoxyloratadine on expression of ICAM-1 and HLA-DR by nasal epithelial cells

Nasal epithelial cells represent the first barrier against noxious agents and allergens. In allergic rhinitis, these cells are activated and histamine may be involved in this activation. Loratadine and one of its active metabolites, descarboethoxyloratadine, were studied for their ability to reduce the activation of nasal epithelial cells by histamine. Nasal turbinates or polyps were removed during surgery from 19 subjects, and nasal epithelial cells were recovered after enzymatic digestion. The in vitro activation of epithelial cells with histamine using an optimal dose (1 microM) and an optimal time (24 h) of incubation was studied, and the effect of loratadine or descarboethoxyloratadine (10 microM) was investigated. The expression of membrane markers (intercellular adhesion molecule-1 (ICAM-1) and a human leukocyte class II antigen (HLA-DR) was assessed by immunocytochemical analysis using an alkaline-antialkaline phosphatase (APAAP) system. The spontaneous expression of both markers was not significantly different in cells recovered from nasal turbinates or polyps, and there was a highly significant increase in the numbers of cells expressing ICAM-1 and HLA-DR following incubation with histamine. Loratadine or descarboethoxyloratadine significantly blocked these effects. This study shows a new possible antiallergic effect of H1-blockers and suggests that their effects on epithelial cells may be relevant in vivo.

Quantification and localization of HLA-DR and intercellular adhesion molecule-1 (ICAM-1) molecules on bronchial epithelial cells of asthmatics using confocal microscopy

An increased expression of HLA-DR and ICAM-1 molecules on bronchial epithelial cells has been observed in asthmatic patients. The aim of this study was to evaluate the localization and to quantify the spontaneous expression of HLA-DR and ICAM-1 on bronchial epithelial cells recovered by bronchial brushing of nine asthmatics and nine controls. Epithelial cells constituted over 95% of cells recovered as shown using an anti-cytokeratin MoAb. Expression of HLA-DR and ICAM-1 was studied using indirect immunofluorescence and confocal microscopy. The intensity of fluorescence of epithelial cells expressing HLA-DR and ICAM-1 was significantly (P < 0.003) increased in asthmatics. In asthmatics, but not in controls, the expression of both molecules was localized in the cytoplasm on the apicolateral portions of the cells. This study shows an up-regulation in the expression of HLA-DR and ICAM-1 molecules by bronchial epithelial cells from asthmatics and a localization of these molecules within the cell.