Concentration-dependent effects of mometasone furoate and dexamethasone on foetal lung fibroblast functions involved in airway inflammation and remodeling

Asthmatic lung fibroblasts promote type 2 immune responses via endoplasmic reticulum stress response dependent thymic stromal lymphopoietin secretion

Lung fibroblasts contribute to asthma pathology partly through modulation of the immune environment in the airway. Tumor necrosis factor-α (TNFα) expression is upregulated in asthmatic lungs. How asthmatic lung fibroblasts respond to TNFα stimulation and subsequently regulate immune responses is not well understood. Endoplasmic reticulum (ER) stress and unfolded protein responses (UPR) play important roles in asthma, but their functional roles are still under investigation. In this study, we investigated TNFα-induced cytokine production in primary lung fibroblasts from asthmatic vs. non-asthmatic human subjects, and downstream effects on type 2 immune responses. TNFα significantly upregulated IL-6, IL-8, C-C motif chemokine ligand 5 (CCL5), and thymic stromal lymphopoietin (TSLP) mRNA expression and protein secretion by lung fibroblasts. Asthmatic lung fibroblasts secreted higher levels of TSLP which promoted IL-33-induced IL-5 and IL-13 production by peripheral blood mononuclear cells. TNFα exposure enhanced expression of ER stress/UPR pathways in both asthmatic and non-asthmatic lung fibroblasts, especially inositol-requiring protein 1α in asthmatics. ER stress/UPR inhibitors decreased IL-6, CCL5, and TSLP protein secretion by asthmatic lung fibroblasts. Our data suggest that TNFα and lung fibroblasts form an important axis in asthmatic lungs to promote asthmatic inflammation that can be attenuated by inhibiting ER stress/UPR pathway.

Bidirectional interaction of airway epithelial remodeling and inflammation in asthma

Asthma is a chronic disease of the airways that has long been viewed predominately as an inflammatory condition. Accordingly, current therapeutic interventions focus primarily on resolving inflammation. However, the mainstay of asthma therapy neither fully improves lung function nor prevents disease exacerbations, suggesting involvement of other factors. An emerging concept now holds that airway remodeling, another major pathological feature of asthma, is as important as inflammation in asthma pathogenesis. Structural changes associated with asthma include disrupted epithelial integrity, subepithelial fibrosis, goblet cell hyperplasia/metaplasia, smooth muscle hypertrophy/hyperplasia, and enhanced vascularity. These alterations are hypothesized to contribute to airway hyperresponsiveness, airway obstruction, airflow limitation, and progressive decline of lung function in asthmatic individuals. Consequently, targeting inflammation alone does not suffice to provide optimal clinical benefits. Here we review asthmatic airway remodeling, focusing on airway epithelium, which is critical to maintaining a healthy respiratory system, and is the primary defense against inhaled irritants. In asthma, airway epithelium is both a mediator and target of inflammation, manifesting remodeling and resulting obstruction among its downstream effects. We also highlight the potential benefits of therapeutically targeting airway structural alterations. Since pathological tissue remodeling is likewise observed in other injury- and inflammation-prone tissues and organs, our discussion may have implications beyond asthma and lung disease.

New targets for resolution of airway remodeling in obstructive lung diseases

Airway remodeling (AR) is a progressive pathological feature of the obstructive lung diseases, including asthma and chronic obstructive pulmonary disease (COPD). The pathology manifests itself in the form of significant, progressive, and (to date) seemingly irreversible changes to distinct respiratory structural compartments. Consequently, AR correlates with disease severity and the gradual decline in pulmonary function associated with asthma and COPD. Although current asthma/COPD drugs manage airway contraction and inflammation, none of these effectively prevent or reverse features of AR. In this review, we provide a brief overview of the features and putative mechanisms affecting AR. We further discuss recently proposed strategies with promise for deterring or treating AR.

Mometasone Furoate Suppresses PMA-Induced MUC-5AC and MUC-2 Production in Human Airway Epithelial Cells

BACKGROUND

Mucus hypersecretion from airway epithelium is a characteristic feature of airway inflammatory diseases. Tumor necrosis factor α (TNF-α) regulates mucin synthesis. Glucocorticoids including mometasone fuorate (MF) have been used to attenuate airway inflammation. However, effects of MF on mucin production have not been reported.

METHODS

Effects of MF and budesonide (BUD) on the phorbol-12-myristate-13-acetate (PMA)-induction of mucin and TNF-α in human airway epithelial cells (NCI-H292) were investigated in the present study. Confluent NCI-H292 cells were pretreated with PMA (200 nM) for 2 hours. Subsequently, the cells were stimulated with MF (1-500 ng/mL) or BUD (21.5 ng/mL) for 8 hours. Dexamethasone (1 µg/mL) was used as the positive control. Real-time polymerase chain reaction was used to determine MUC2 and MUC5AC mRNA levels. The level of total mucin, MUC2, MUC5AC, and TNF-α in culture supernatants were measured using enzyme-linked immunosorbent assay.

RESULTS

MF and BUD significantly suppressed MUC2 and MUC5AC gene expression in PMA-stimulated NCI-H292 cells. The inhibitory effects of the two steroid drugs were also observed in the production of total mucin, MUC2 and MUC5AC proteins, and TNF-α.

CONCLUSION

Our findings demonstrated that MF and BUD attenuated mucin and TNF-α production in PMA-induced human airway epithelial cells.

Concomitant inhibition of primary equine bronchial fibroblast proliferation and differentiation by selective β2-adrenoceptor agonists and dexamethasone

Altered airway cell proliferation plays an important role in the pathogenesis of human bronchial asthma and chronic obstructive pulmonary disease (COPD) as well as the equine recurrent airway obstruction (RAO) with consistent changes, i.e. narrowing the airway wall, explained by proliferation and differentiation of fibroblasts. In permanent cell lines, it has been suggested that β2-adrenoceptor agonists and glucocorticoids regulate cell proliferation via the β2-adrenoceptor pathway; indeed, no study was carried out in fresh isolated primary equine bronchial fibroblasts (EBF). We characterized the β-adrenoceptors in EBF, and compared effects of long-acting (clenbuterol) and short-acting (salbutamol and isoproterenol) β2-agonists and dexamethasone on proliferation, differentiation and collagen synthesis. High density (Bmax; 5037±494 sites/cell) of β2-adrenoceptor subtype was expressed in EBF. β2-agonists inhibited concentration-dependently EBF proliferation with potency of clenbuterol>salbutamol »isoproterenol which was inhibited by ICI 118.551 and propranolol but not by CGP 20712A. In contrast, dexamethasone alone inhibited less EBF proliferation, but the effect was high when dexamethasone was combined with β2-agonists. Transforming growth factor-β1 (TGF-β1) increased transformation of fibroblasts into myofibroblasts, which was inhibited by clenbuterol and dexamethasone alone and drug combination resulted in high inhibition rate. Collagen synthesis in EBF was rather hampered by dexamethasone than by β-agonists. Collectively, the expression of β2-adrenoceptor subtype in EBF and the anti-proliferative effect of clenbuterol suggest that β2-adrenoceptors are growth inhibitory and anti-fibrotic in EBF. These β2-agonist effects in EBF were synergistically enhanced by dexamethasone, providing the additive effects of glucocorticoids to counteract airway remodelling and morbidity of asthma and RAO.

Plasmacytoid dendritic cells in allergic asthma and the role of inhaled corticosteroid treatment

BACKGROUND

Plasmacytoid dendritic cells (pDCs) infiltrate sites of acute Th2-dominant inflammation, but their role in allergic asthma remains unclear.

OBJECTIVE

To characterize circulating pDCs from patients with allergic asthma outside their respective allergen season.

METHODS

Adhesion molecules, co-stimulatory molecules, immunoglobulin receptors and chemokine receptors were quantified on blood pDCs from 20 patients with allergic asthma and 18 healthy controls using flow cytometry. In addition, IL-6-, TNF-α- and IFN-α-secretion were analysed after stimulating isolated pDCs with TLR7- and TLR9-ligands.

RESULTS

Plasmacytoid dendritic cells from patients with allergic asthma showed an increased expression of chemokine receptors involved in inflamed tissue homing such as CCR2, CCR4, CCR9, CCR10, CXCR2, CXCR5 and CXCR6, while the expression of the lymph node homing receptor CXCR3 was down-regulated. In addition, these pDCs exhibited a higher expression of activation markers and Th2-associated molecules such as CD40, CD62L, CD64 and FcεRIα. In contrast, TLR7-mediated IL-6-, TNF-α- and IFN-α-secretion was significantly reduced in pDCs from patients with asthma. The TLR9-mediated cytokine response was only suppressed in those patients who were treated with inhaled corticosteroids (ICS) during previous allergen seasons. The same effect was observed for CD54 and OX40L expression.

CONCLUSIONS

We report an increased expression of activation markers, and Th2-associated molecules, and an increased migratory potential of circulating pDCs in allergic asthma. These changes are accompanied by a reduced TLR7-mediated cytokine response. In addition, our results suggest a longterm impact of ICS treatment on the characteristics of circulating pDCs.

Dexamethasone and salbutamol stimulate human lung fibroblast proliferation

BACKGROUND

Asthma is characterized by bronchial hyperreactivity and airway remodeling. Subepithelial fibrosis, a feature of remodeling, is accompanied by activation of fibroblasts to myofibroblasts, with excessive proliferation and increased collagen, extracellular matrix protein, and profibrogenic cytokine production. Mast cells are important in the development of asthma and its fibrotic changes.

OBJECTIVE

In this study, we aimed to investigate the direct effect of the drugs most frequently used in asthma, that is, glucocorticosteroids (dexamethasone) and shortacting β(2)-agonists (salbutamol), on human lung fibroblast proliferation when unstimulated or activated by mast cells or eotaxin.

METHODS

Subconfluent human fetal lung or bronchial fibroblasts were incubated with different concentrations of the drugs (24 h) 6 activators, and [(3)H]-Thymidine was added (24 h) to measure their proliferation. IL-6 production in the supernatants of confluent monolayers cultured in the presence of the drugs or forskolin (24 h) was analyzed by enzyme-linked immunosorbent assay.

RESULTS

Both drugs alone and in the presence of the activators enhanced fibroblast proliferation in a seemingly synergistic way for both fetal and bronchial fibroblasts. Dexamethasone was found to decrease IL-6 production, while salbutamol increased it.

CONCLUSIONS

These observations if corroborated by in vivo data may possibly account for the deleterious effect of long-term therapy with β(2)-bronchodilators and inhaled glucocorticosteroids on the natural history of asthma.

Remodeling in asthma

Airway remodeling encompasses the structural alterations in asthmatic compared with normal airways. Airway remodeling in asthmatic patients involves a wide array of pathophysiologic features, including epithelial changes, increased smooth muscle mass, increased numbers of activated fibroblasts/myofibroblasts, subepithelial fibrosis, and vascular changes. Multiple cytokines, chemokines, and growth factors released from both inflammatory and structural cells in the airway tissue create a complex signaling environment that drives these structural changes. However, recent investigations have changed our understanding of asthma from a purely inflammatory disease to a disease in which both inflammatory and structural components are equally involved. Several reports have suggested that asthma primarily develops because of serious defects in the epithelial layer that allow environmental allergens, microorganisms, and toxins greater access to the airway tissue and that can also stimulate the release of mediators from the epithelium, thus contributing to tissue remodeling. Lung-resident fibroblasts and smooth muscle cells have also been implicated in the pathogenesis of airway remodeling. Remodeling is assumed to result in persistent airflow limitation, a decrease in lung function, and airway hyperresponsiveness. Asthmatic subjects experience an accelerated decrease in lung function compared with healthy subjects, which is proportionally related to the duration and severity of their disease.

Mometasone and desloratadine additive effect on eosinophil survival and cytokine secretion from epithelial cells

Background

Although antihistamines and topical corticosteroids are used in combination to treat allergic rhinitis, their additive effect has not been yet demonstrated. The aim was investigate the antiinflammatory additive effect of mometasone and desloratadine on cytokine and sICAM-1 secretion by epithelial cells, and on eosinophil survival stimulated by human epithelial cells secretions from nasal mucosa and polyps.

Methods

Epithelial cells obtained from nasal mucosa or polyps were stimulated with 10% fetal bovine serum in presence of mometasone (10^-11M-10^-5M) with/without desloratadine (10^-5M). Cytokine and sICAM-1 concentrations in supernatants were measured by ELISA. Peripheral blood eosinophils were incubated during 4 days with epithelial cell secretions with (10^-11M-10^-5M) and/or desloratadine (10^-5M) and survival assessed by Trypan blue. Results are expressed as percentage (mean ± SEM) compared to control.

Results

Fetal bovine serum stimulated IL-6, IL-8, GM-CSF and sICAM-1 secretion. In mucosa and polyp epithelial cells, mometasone inhibited this induced secretion while desloratadine inhibited IL-6 and IL-8. The combination of 10^-5M desloratadine and 10^-9M mometasone reduced IL-6 secretion (48 ± 11%, p < 0.05) greater extent than mometasone alone (68 ± 10%) compared to control (100%). Epithelial cell secretions induced eosinophil survival from day 1 to 4, this effect being inhibited by mometasone. At day 4, the combination of mometasone (10^-11M) and desloratadine (10^-5M) provoked an increased inhibition of eosinophil survival induced by cell secretions (27 ± 5%, p < 0.01) than mometasone (44 ± 7%) or desloratadine (46 ± 7%) alone.

Conclusions

These results suggest that the combination of desloratadine and mometasone furoate have a greater antinflammatory effect in an in vitro model of eosinophil inflammation than those drugs administered alone.

Dexamethasone and Salbutamol Stimulate Human Lung Fibroblast Proliferation

Background

Asthma is characterized by bronchial hyperreactivity and airway remodeling. Subepithelial fibrosis, a feature of remodeling, is accompanied by activation of fibroblasts to myofibroblasts, with excessive proliferation and increased collagen, extracellular matrix protein, and profibrogenic cytokine production. Mast cells are important in the development of asthma and its fibrotic changes.

Objective

In this study, we aimed to investigate the direct effect of the drugs most frequently used in asthma, that is, glucocorticosteroids (dexamethasone) and shortacting β₂-agonists (salbutamol), on human lung fibroblast proliferation when unstimulated or activated by mast cells or eotaxin.

Methods

Subconfluent human fetal lung or bronchial fibroblasts were incubated with different concentrations of the drugs (24 h) 6 activators, and [³H]-Thymidine was added (24 h) to measure their proliferation. IL-6 production in the supernatants of confluent monolayers cultured in the presence of the drugs or forskolin (24 h) was analyzed by enzyme-linked immunosorbent assay.

Results

Both drugs alone and in the presence of the activators enhanced fibroblast proliferation in a seemingly synergistic way for both fetal and bronchial fibroblasts. Dexamethasone was found to decrease IL-6 production, while salbutamol increased it.

Conclusions

These observations if corroborated by in vivo data may possibly account for the deleterious effect of long-term therapy with β₂-bronchodilators and inhaled glucocorticosteroids on the natural history of asthma.

The roles of transforming growth factor-β₁ and vascular endothelial growth factor in the tracheal granulation formation

BACKGROUND

Acquired tracheal stenosis is common in patients with a long-term tracheostomy and granulation is one of the most commonly observed lesions in benign airway stenosis. The aim of this study was to investigate the mechanisms of tracheal granulation formation and find the potential therapeutic targets to prevent the granulation formation.

RESULTS

In granulation tissue obtained from patients during interventional bronchoscopy for the relief of airway obstruction, increased expression of transforming growth factor (TGF)-β₁ and vascular endothelial growth factor (VEGF), as well as increased numbers of fibroblasts, was found by immunohistochemical staining. TGF-β₁ expression was detected in both the epithelial and submucosal layers. The highest levels of VEGF and vimentin expression occurred in the submucosal layers. In comparison with the control, significantly increased numbers of small vessels were observed in the submucosal layers of the granulation tissue. In vitro, TGF-β₁ stimulated production of VEGF by cultured fibroblasts at both the mRNA and protein level. VEGF siRNA treatment resulted in a significant decrease of TGF-β₁-induced VEGF production. SIS3, a selective Smad3 inhibitor, and UO126 both inhibited p44/42 MAP kinase phosphorylation and attenuated subsequent VEGF production by fibroblasts. A low concentration of erythromycin (1 μg/ml), but not dexamethasone (100 μM), inhibited TGF-β₁-induced VEGF production.

CONCLUSION

This study provides important information that facilitates an understanding, at least in part, of the mechanisms of granulation formation. Targeting these mediators and cells may help to prevent the formation of granulation tissue in long-term tracheostomy or prolonged endotracheal intubation patients.

Lower sensitivity of nasal polyp fibroblasts to glucocorticoid anti-proliferative effects

BACKGROUND

Treatment with glucocorticoids (GCs) is the cornerstone of nasal polyp (NP) therapy, but some patients respond poorly to them. Fibroblasts are involved in both inflammation and remodelling of NP. We aimed to evaluate whether NP fibroblasts are less sensitive to GCs' anti-proliferative and anti-inflammatory effects, compared to nasal mucosa (NM) fibroblasts.

METHODS

Fibroblasts were obtained from NP (n = 8) from asthmatic patients undergoing endoscopic surgery and NM (n = 8) from patients undergoing nasal corrective surgery. Fibroblasts were stimulated with DMEM at 0.5% or 5% FBS, or TGF-β (5 ng/ml), with or without dexamethasone (10(-11) to 10(-5)M) for different times. Cell proliferation, collagen mRNA expression and IL-6 and IL-8 release were measured.

RESULTS

After 3-days, dexamethasone dose-dependently inhibited proliferation of NM (p < 0.001) but not that of NP fibroblasts. Dexamethasone (10(-6)M) reduced by 25% the proliferation of NM fibroblasts. Dexamethasone also inhibited proliferation of NM (p < 0.01) but not that of NP fibroblasts at 5-days. TGF-β induced collagen-1α1, -1α2, and -3α1 mRNA levels in both NM and NP fibroblasts (p < 0.05), and dexamethasone did not alter TGF-β-induced collagen mRNA levels in either fibroblast type at 24 h. Dexamethasone dose-dependently decreased (p < 0.05) FBS-induced IL-6 and IL-8 release in both NM and NP fibroblasts at 4 h, although at 10(-8)M, dexamethasone inhibited cytokine production in NM (p < 0.05) but not in NP fibroblasts.

CONCLUSIONS

This impaired sensitivity of nasal polyp fibroblasts to in vitro glucocorticoid effects concurs in part with the poor clinical response that these nasal polyp patients show to glucocorticoid treatment.

Airway remodelling in asthma: from benchside to clinical practice

Airway remodelling refers to the structural changes that occur in both large and small airways relevant to miscellaneous diseases including asthma. In asthma, airway structural changes include subepithelial fibrosis, increased smooth muscle mass, gland enlargement, neovascularization and epithelial alterations. Although controversial, airway remodelling is commonly attributed to an underlying chronic inflammatory process. These remodelling changes contribute to thickening of airway walls and, consequently, lead to airway narrowing, bronchial hyper-responsiveness, airway edema and mucous hypersecretion. Airway remodelling is associated with poor clinical outcomes among asthmatic patients. Early diagnosis and prevention of airway remodelling has the potential to decrease disease severity, improve control and prevent disease expression. The relationship between structural changes and clinical and functional abnormalities clearly deserves further investigation. The present review briefly describes the characteristic features of airway remodelling observed in asthma, its clinical consequences and relevance for physicians, and its modulation by therapeutic approaches used in the treatment of asthmatic patients.

Mometasone furoate: an effective anti-inflammatory with a well-defined safety and tolerability profile in the treatment of asthma

Inhaled corticosteroids (ICS) are recommended as a controller medication in the most recent Global Initiative for Asthma and the National Heart, Lung and Blood Institute guidelines. Mometasone furoate (MF) is an effective, well-tolerated inhaled steroid and is indicated for the maintenance treatment of adult and adolescent patients (> or = 12 years) with persistent asthma. MF is approved for once or bid maintenance treatment of asthma (in patients previously receiving ICS or bronchodilators). Low systemic bioavailability and high relative binding affinity for the glucocorticoid receptor are properties of MF that allow for a favourable efficacy and tolerability profile. Inhaled MF has been shown to be an effective and well-tolerated controller medication for those patients with mild, moderate or severe persistent asthma. MF has recently been approved by the US regulatory authorities for use in children (4-11 years). Future developments include the combination of MF with the long-acting bronchodilators, formoterol and indacaterol, to provide additional options in the treatment of asthma.

CD44 and Bak expression in IL-6 or TNF-alpha gene knockout mice after whole lung irradiation

To understand the molecular mechanisms that underlie radiation pneumonitis, we examined whether knockout of the TNF or the IL-6 gene could give mice an inherent resistance to radiation in the acute phase of alveolar damage after thoracic irradiation. The temporal expression of inflammation (CD44) and apoptosis (Bak) markers in lung after thoracic irradiation was measured to determine the degree of alveolar damage. At 4 weeks post-irradiation (10 Gy), small inflammatory foci were observed in all mice, but there were no obvious histological differences between control (C57BL/6JSlc), TNF-alpha knockout (TNF KO), and IL-6 knockout (IL-6 KO) mice. However, immunohistochemical analysis of CD44 and Bak expression over a time course of 2 weeks highlighted significant differences between the three groups. C57BL/6JSlc and TNF KO mice had increased numbers of both CD44-positive and Bak-positive cells after irradiation, while the IL-6 KO mice showed stable levels of CD44 and Bak. In conclusion, the radioresistant status of IL-6 KO mice in the acute phase of alveolar damage after irradiation suggested an important role for IL-6 in radiation pneumonitis.

Exposure of airway epithelium to bile acids associated with gastroesophageal reflux symptoms: a relation to transforming growth factor-beta1 production and fibroblast proliferation

RATIONALE

Gastroesophageal reflux (GER) is common in patients with various airway diseases. Airway epithelial cells can release growth factors that promote fibroblast proliferation. Exposure of airway epithelium to bile acids may induce a fibrotic response.

OBJECTIVES

To determine how bile acids interact with airway epithelium; particularly, whether transforming growth factor-beta1 secretion and fibroblast proliferation are affected.

METHODS

Induced sputum from patients with asthma, GER, or asthma associated with GER symptoms, or from healthy control subjects was collected. Total bile acids were measured by a spectrophotometric enzymatic assay. The major components of bile acids, chenodeoxycholic acid (CD) and glycochenodeoxycholic acid (GCD), were used to stimulate primary airway epithelial cells. Quantitative polymerase chain reaction and Western blotting were applied for messenger RNA expression and signal pathway analysis, respectively. Conditioned medium following CD stimulation was coincubated with fibroblasts for proliferation study.

RESULTS

The amount of total bile acids in induced sputum was significantly higher in patients with GER and asthma-associated GER symptoms compared to that of healthy control subjects (p<0.005). CD, but not GCD, significantly induced TGF-beta1 production. TGF-beta1 messenger RNA expression was 2.5-fold increased compared to unstimulated cells. This occurred via p38 mitogen-activated protein (MAP) kinase and activating transcription factor-2 activation. Pretreatment with dexamethasone inhibited TGF-beta1 production at both messenger RNA and protein levels by inhibiting p38 MAP kinase phosphorylation. Conditioned medium from CD-treated epithelial cells enhanced fibroblast proliferation.

CONCLUSIONS

Aspiration of bile acids may induce airway fibrosis through the production of TGF-beta1 and fibroblast proliferation. Early intervention to attenuate these processes may reduce fibrogenesis in various airway diseases associated with GER.

Modulation of human lung fibroblast functions by ciclesonide: evidence for its conversion into the active metabolite desisobutyryl-ciclesonide

BACKGROUND

Ciclesonide, an inhaled corticosteroid administered as inactive compound with almost no binding affinity for the glucocorticoid receptor, is clinically effective in asthma being converted by airway epithelial cells into its active metabolite desisobutyryl-(des)-ciclesonide.

AIM

To evaluate whether ciclesonide could directly modulate in vitro bronchial fibroblast functions being converted into des-ciclesonide by these pluripotent cells involved in the regulation of airway inflammation and remodelling.

METHODS

Ciclesonide (0.09-9.0 microM) was added to a human adult lung fibroblast cell line (CCL-202), seeded in medium in the presence of the following cytokines and growth factors: (a) basic fibroblast growth factor (bFGF) for cell proliferation, measured by tritiated thymidine ([3H]TdR) incorporation; (b) tumour necrosis factor (TNF)-alpha, to stimulate intercellular adhesion molecule (ICAM)-1 expression and monocyte chemoattractant protein-1 (MCP-1) and eotaxin release, evaluated by flow cytometry and ELISA, respectively; (c) transforming growth factor (TGF)-beta1, for induction of alpha smooth muscle actin (alpha-SMA) protein expression and modification of the organization of alpha-SMA stress fibres, evaluated by Western blot analysis and fluorescence microscopy.

RESULTS

The presence of ciclesonide in cell cultures induced a significant downregulation of: (a) bFGF-induced fibroblast proliferation and TNF-alpha-induced ICAM-1 expression, at the 0.3-9.0 microM concentrations (p<0.05); (b) TNF-alpha-induced MCP-1 release, at all the concentrations tested (p<0.05); (c) TNF-alpha-induced eotaxin release, at the three highest concentrations (0.9-9.0 microM) (p<0.05); (d) TGF-beta1-induced of alpha-SMA protein expression at the 0.3-3.0 microM concentrations, associated with a reduction in the organization of alpha-SMA stress fibres.

CONCLUSIONS

These data show at cellular level an effective anti-inflammatory activity of ciclesonide on human lung fibroblasts and support the hypothesis that also these cells, in addition to airway epithelial cells, may be involved in converting the parental compound into its active metabolite in the airways.

Intercellular adhesion molecule-1: a consistent inflammatory marker of the cutaneous radiation reaction both in vitro and in vivo

BACKGROUND

Radiation damage to skin is a key diagnostic and prognostic parameter for patients accidentally exposed to radiation. Moreover, skin is a target organ for crucial side-effects of routine radiotherapy. The pathophysiology of the cutaneous radiation reaction is in many respects still unknown. The acute inflammatory radiation reaction of skin has been shown to involve alterations in cell-cell and cell-matrix interactions, which are mediated by cellular adhesion molecules.

OBJECTIVES

To evaluate the effect of ionizing radiation on intercellular adhesion molecule-1 (ICAM-1) expression in human skin cells.

METHODS

Dermal monolayer cells, a three-dimensional skin model and skin biopsies were investigated for ICAM-1 expression after ionizing radiation using flow cytometry, quantitative reverse transcription-polymerase chain reaction and immunohistochemistry. ICAM-1 expression in monolayer cells pretreated with protein kinase inhibitors and dexamethasone prior to irradiation was analysed by flow cytometry.

RESULTS

Using different sources of skin cells, we demonstrated a consistent upregulation of both ICAM-1 mRNA and protein expression by ionizing radiation. Blocking experiments revealed that tumour necrosis factor-alpha, another ICAM-1 inducer, does not account for the effect of radiation. Radiation-induced upregulation of ICAM-1 expression was significantly attenuated by inhibitors to protein kinase C, mitogen-activated protein (MAP) ERK kinase, p38 MAP kinase and phosphatidylinositol 3-kinase. The anti-inflammatory agent dexamethasone suppressed the effect of radiation on ICAM-1 expression, suggesting its usefulness to treat the cutaneous radiation reaction.

CONCLUSIONS

Our data suggest that ICAM-1 is a consistent inflammatory parameter of the cutaneous radiation reaction both in vitro and in vivo that might provide new therapeutic options for diagnosis and treatment of effects of radiation.

Combined fluticasone propionate and salmeterol reduces RSV infection more effectively than either of them alone in allergen-sensitized mice

BACKGROUND

Respiratory syncytial virus (RSV) infection is the major cause of bronchiolitis in infants and is a risk factor for the development of asthma. Allergic asthmatics are more susceptible to RSV infection and viral exacerbation.

METHODS

Since the effectiveness of corticosteroids in treating RSV infection has been controversial, we tested fluticasone propionate (FP) and salmeterol (Sal) alone versus FP plus Sal (FPS) on RSV-induced airway inflammation. Mice were sensitized and challenged with ovalbumin (OVA) and infected with RSV. Following infection they were treated with FP, Sal, or FPS intranasally and airway hyperreactivity (AHR), inflammation and RSV titers were examined.

RESULTS

The group treated with FPS showed significantly lower AHR compared to the group treated with FP or Sal alone. The group treated with FP alone showed slightly decreased (non-significant) AHR compared to controls. Treatment with FPS resulted in significant decreases in the percentage of eosinophils and neutrophils in bronchoalveolar lavage fluid and in lung pathology compared to FP or Sal. FP alone decreased eosinophils but not neutrophils or lymphocytes, while Sal alone decreased eosinophils and neutrophils but not lymphocytes. FPS treatment of mice infected with RSV in the absence of allergen sensitization resulted in a 50% decrease of RSV titer in the lung and a reduction in neutrophils compared to FP or Sal.

CONCLUSION

Together, these results indicate that fluticasone in combination with salmeterol is a more effective treatment for decreasing airway hyperreactivity and inflammation than either of them alone in allergen-sensitized, RSV-infected mice.

Structural changes in airway diseases: characteristics, mechanisms, consequences, and pharmacologic modulation

In airway diseases such as asthma and COPD, specific structural changes may be observed, very likely secondary to an underlying inflammatory process. Although it is still controversial, airway remodeling may contribute to the development of these diseases and to their clinical expression and outcome. Airway remodeling has been described in asthma in various degrees of severity, and correlations have been found between such features as increase in subepithelial collagen or proteoglycan deposits and airway responsiveness. Although the clinical significance of airway remodeling remains a matter of debate, it has been suggested as a potential target for treatments aimed at reducing asthma severity, improving its control, and possibly preventing its development. To date, drugs used to treat airway diseases have a little influence on airway structural changes. More research should be done to identify key changes, valuable treatments, and proper interventional timing to counteract these changes. The potential of novel therapeutic agents to reverse or prevent airway remodeling is an exciting avenue and warrants further evaluation.

Concentration-dependent activity of mometasone furoate and dexamethasone on blood eosinophils isolated from atopic children: modulation of Mac-1 expression and chemotaxis

Treatment of asthma with corticosteroids results in downregulation of eosinophilic airway inflammation. We evaluated in vitro the activity of an "inhaled" corticosteroid, mometasone furoate (MF), and of a "systemic" corticosteroid, dexamethasone (DEX), on eosinophil functions, i.e. adhesion molecule expression and cell chemotaxis. Partially purified blood eosinophils were obtained from 18 asthmatic subjects sensitized to house dust mites. The expression of the macrophage antigen (Mac)-1 (CD11b/CD18) was measured by specific monoclonal antibody (mAb) staining and flow cytometry analysis at baseline or after stimulation with N-formyl-methionyl-leucyl-phenylalanine (fMLP) or with recombinant human (rh) granulocyte macrophage-colony stimulating factor (GM-CSF) plus a mAb anti-human (ah) IgE low affinity receptor [FcepsilonRII or CD23]. Cell chemotaxis toward the complement fragment 5a (C5a) or rh interleukin (IL)-5 was evaluated in Boyden microchambers by light microscopy. Eosinophils showed a significant increase in Mac-1 expression after activation with fMLP or with rh GM-CSF plus ah CD23 mAbs (p<0.05, each comparison) and a remarkable chemotactic response to both C5a or rh IL-5 (p<0.001, each comparison). To test the inhibitory activity of MF and DEX on eosinophil functions, the cells were preincubated for 3 h with four concentrations (0.1, 1, 10 and 100 nM) of each of the two drugs, before being activated by fMLP or by rh GM-CSF plus ah CD23 mAbs or tested with C5a or with rh IL-5. Independently of the stimulus used, both Mac-1 expression and eosinophil migration were effectively downregulated by preincubation with MF or DEX at 1, 10 and 100 nM (p<0.05). The inhibitory activity on cell chemotaxis in response to both C5a or with rh IL-5 was higher for MF than DEX, but only at the highest concentration tested (p<0.05, each comparison). These data demonstrate that concentrations of MF similar to those obtained in vivo are highly effective in inhibiting eosinophil functions involved in airway inflammation.

Rhinovirus infects primary human airway fibroblasts and induces a neutrophil chemokine and a permeability factor

The events linking rhinovirus (RV) infection to airway symptoms are poorly understood. The virus initially infects airway epithelium followed by a vigorous inflammatory response that may entail spread of RV from epithelium to other cells in the airway wall. However, RV has fastidious growth characteristics and to date reproductive infection of primary cells other than human airway epithelium has not been confirmed. Airway fibroblasts are adjacent to and in contact with epithelial cells, play a key role in innate immune responses, and may participate in the evolution of inflammation. To investigate fibroblast actions, we first determined whether RV could infect and replicate in primary culture human lung fibroblasts. RV serotype 16 (RV16) was used to infect fibroblasts grown from lung tissue, and virus infection with replication was demonstrated by a combination of techniques. RT-PCR was used to show an increase in RV transcription; confocal microscopy demonstrated colocalization of the replicative form of RV genome (double-stranded RNA) and RV16 proteins; infectious virus was also recovered from the culture supernatant of infected fibroblasts. Functional consequences of RV infection were next examined. RV infection of fibroblasts was followed by an increase in epithelial neutrophil-activating peptide-78 (ENA-78) mRNA and protein. The permeability factor vascular endothelial growth factor (VEGF) was also induced over a similar time course. These data suggest that interactions between RV and human fibroblasts are feasible, may coordinate neutrophil chemoattraction with enhanced vascular permeability and that fibroblasts may contribute to inflammatory responses following RV infections.