Giuseppina Chiappara

Evaluation of apoptosis of eosinophils, macrophages, and T lymphocytes in mucosal biopsy specimens of patients with asthma and chronic bronchitis

BACKGROUND Apoptosis regulates inflammatory cell survival, and its reduction contributes to the chronicity of an inflammatory process. Apoptosis is controlled by suppressing or inducing genes, such as bcl-2 and p53, respectively. OBJECTIVE We sought to assess apoptosis of eosinophils, macrophages, and T lymphocytes in bronchial biopsy specimens from asthmatic subjects and to examine its regulation by evaluating the expression of B-cell lymphoma leukemia-2 (Bcl-2) and P53 proteins. We also sought to explore the relationships between cell apoptosis and GM-CSF, a cytokine able to increase eosinophil and macrophage survival. METHODS Apoptosis in eosinophils, macrophages, and T lymphocytes was evaluated in bronchial biopsy specimens obtained from 30 asthmatic subjects, 26 subjects with chronic bronchitis, and 15 control subjects by combining the terminal deoxynucleotidyl transferase-mediated dNTP nick end-labeling technique and immunohistochemistry. The expression of P53, Bcl-2, and GM-CSF was studied through immunohistochemistry by using specific mAbs. RESULTS The number of apoptotic eosinophils and macrophages was lower in subjects with asthma than in those with chronic bronchitis (P <.007 and P <.001, respectively) and inversely correlated with the clinical severity of asthma (P <.001 and P <.002, respectively). Few T lymphocytes were apoptotic in all groups studied. In asthma GM-CSF+ cells correlated with the number of nonapoptotic eosinophils and macrophages (P =.0001) and with the severity of the disease (P <.003). In asthma Bcl-2+ cells were higher than in control subjects and subjects with chronic bronchitis (P <.002 and P <.015, respectively), they outnumbered P53+ cells, and they correlated with the number of T lymphocytes (P <.001) and with the severity of the disease (P <.003). CONCLUSION Airway inflammation in asthma is associated with an enhanced survival of different cell types caused by reduced apoptosis.

Leptin and leptin receptor expression in asthma.

BACKGROUND The adipokine leptin is a potential new mediator for bronchial epithelial homeostasis. Asthma is a chronic inflammatory disease characterized by airway remodeling that might affect disease chronicity and severity. TGF-beta is a tissue growth factor the dysregulation of which is associated with airway remodeling. OBJECTIVE We sought to determine whether a bronchial epithelial dysfunction of the leptin/leptin receptor pathway contributes to asthma pathogenesis and severity. METHODS We investigated in vitro the presence of leptin/leptin receptor on human bronchial epithelial cells. Then we studied the effect of TGF-beta and fluticasone propionate on leptin receptor expression. Finally, the role of leptin on TGF-beta release and cell proliferation was analyzed. Ex vivo we investigated the presence of leptin/leptin receptor in the epithelium of bronchial biopsy specimens from subjects with asthma of various severities and from healthy volunteers, and some features of airway remodeling, such as reticular basement membrane (RBM) thickness and TGF-beta expression in the epithelium, were assessed. RESULTS In vitro bronchial epithelial cells express leptin/leptin receptor. TGF-beta decreased and fluticasone propionate increased leptin receptor expression, and leptin decreased the spontaneous release of TGF-beta and increased cell proliferation. Ex vivo the bronchial epithelium of subjects with mild, uncontrolled, untreated asthma showed a decrease expression of leptin and its receptor and an increased RBM thickness and TGF-beta expression when compared with values seen in healthy volunteers. Furthermore, severe asthma was associated with a reduced expression of leptin and its receptor and an increased RBM thickness with unaltered TGF-beta expression. CONCLUSIONS Decreased expression of leptin/leptin receptor characterizes severe asthma and is associated with airway remodeling features.

Does leptin play a cytokine-like role within the airways of COPD patients?

The leptin-leptin receptor system might be up-regulated in the airways of chronic obstructive pulmonary disease (COPD). In bronchial biopsies obtained from normal subjects and smokers, with and without COPD, the present study examined leptin and leptin-receptor expression and their co-localisation in airway and inflammatory cells. Combining immunohistochemistry with terminal deoxynucleotidyl transferase dUTP nick end-labelling techniques, apoptosis in airway and inflammatory cells and in leptin and leptin-receptor expressing cells was investigated. In the epithelial cells both leptin and leptin-receptor expression was higher in normal subjects than in smokers and COPD subjects. By contrast, in the sub-mucosa, leptin was over-expressed in COPD when compared with normal subjects and smokers. Leptin and its receptor were co-localised, mainly with activated T cells (CD45R0) and CD8+ T lymphocytes. In smokers, apoptosis was found in some inflammatory cells, whereas in COPD inflammatory cells, leptin and leptin-receptor positive cells were not apoptotic. Leptin expression was related to COPD severity and assessed using the Global initiative for Chronic Obstructive Lung Disease classification. In conclusion, the present study shows an increased leptin expression in bronchial mucosa of chronic obstructive pulmonary disease patients, associated with airway inflammation and airflow obstruction.

Inflammatory features of nasal mucosa in smokers with and without COPD

Background: To investigate whether nasal and bronchial inflammation coexists in chronic obstructive pulmonary disease (COPD), nasal and bronchial biopsy specimens from seven control subjects, seven smokers without COPD, and 14 smokers with COPD were studied. Methods: Nasal and bronchial biopsy specimens were taken from the same patients during bronchoscopy and squamous cell metaplasia and the thickness of the epithelium and basement membrane were measured. The numbers of eosinophils (EG2), neutrophils (elastase), macrophages (CD68), and CD8 T lymphocytes (CD8/144B) were assessed by immunohistochemistry. Results: Smokers with and without COPD had squamous metaplasia in the nasal and bronchial epithelium. In all groups the thickness of the nasal epithelium was greater than that of the bronchial epithelium. The thickness of the basement membrane was similar in nasal and bronchial biopsy specimens from smokers with and without COPD, but was greater in the bronchi than in the nasal epithelium of controls. Eosinophil number was higher in the nasal and bronchial mucosa of smokers without COPD than in smokers with COPD or controls. Neutrophil number was higher in the nasal and bronchial mucosa of smokers with COPD than in smokers without COPD or controls. CD8 T lymphocyte numbers were similar in smokers with and without COPD and higher than in controls. There were fewer macrophages in nasal and bronchial biopsy specimens from smokers without COPD than in those with COPD. Conclusion: Nasal and bronchial inflammation coexists in smokers and is characterised by infiltration of CD8 T lymphocytes. In smokers without COPD this feature is associated with an increased number of eosinophils, while in those with COPD it is linked to an increased number of neutrophils in both nasal and bronchial biopsy specimens.

Heat shock protein-27 protects human bronchial epithelial cells against oxidative stress–mediated apoptosis: possible implication in asthma

Abstract Inflammation of the human bronchial epithelium, as observed in asthmatics, is characterized by the selective death of the columnar epithelial cells, which desquamate from the basal cells. Tissue repair initiates from basal cells that resist inflammation. Here, we have evaluated the extent of apoptosis as well as the Hsp27 level of expression in epithelial cells from bronchial biopsy samples taken from normal and asthmatic subjects. Hsp27 is a chaperone whose expression protects against oxidative stress. We report that in asthmatic subjects the basal epithelium cells express a high level of Hsp27 but no apoptotic morphology. In contrast, apoptotic columnar cells are devoid of Hsp27 expression. Moreover, we observed a decreased resistance to hydrogen peroxide–induced apoptosis in human bronchial epithelial 16–HBE cells when they were genetically modified to express reduced levels of Hsp27.

Beta defensin-2 is reduced in central but not in distal airways of smoker COPD patients.

Background Altered pulmonary defenses in chronic obstructive pulmonary disease (COPD) may promote distal airways bacterial colonization. The expression/activation of Toll Like receptors (TLR) and beta 2 defensin (HBD2) release by epithelial cells crucially affect pulmonary defence mechanisms. Methods The epithelial expression of TLR4 and of HBD2 was assessed in surgical specimens from current smokers COPD (s-COPD; n = 17), ex-smokers COPD (ex-s-COPD; n = 8), smokers without COPD (S; n = 12), and from non-smoker non-COPD subjects (C; n = 13). Results In distal airways, s-COPD highly expressed TLR4 and HBD2. In central airways, S and s-COPD showed increased TLR4 expression. Lower HBD2 expression was observed in central airways of s-COPD when compared to S and to ex-s-COPD. s-COPD had a reduced HBD2 gene expression as demonstrated by real-time PCR on micro-dissected bronchial epithelial cells. Furthermore, HBD2 expression positively correlated with FEV1/FVC ratio and inversely correlated with the cigarette smoke exposure. In a bronchial epithelial cell line (16 HBE) IL-1β significantly induced the HBD2 mRNA expression and cigarette smoke extracts significantly counteracted this IL-1 mediated effect reducing both the activation of NFkB pathway and the interaction between NFkB and HBD2 promoter. Conclusions This study provides new insights on the possible mechanisms involved in the alteration of innate immunity mechanisms in COPD.

Apoptosis and airway inflammation in asthma

Asthma is a disease characterized by a chronic inflammation of the airways and by structural alterations of bron-chial tissues, often referred to as airway remodelling. The development of chronic airway inflammation in asthma depends upon the continuous recruitment of inflammatory cells from the bloodstream towards the bronchial mucosa and by their subsequent activation. It is however increasingly accepted that mechanisms involved in the regulation of the survival and apoptosis of inflammatory cells may play a central role in the persistent inflammatory process characterizing this disease. Increased cellular recruitment and activation, enhanced cell survival and cell:cell interactions are therefore the key steps in the development of chronic airway inflammation in asthma, and represent the major causes for tissue damge, repair and remodelling.

Theophylline suppresses the release of tumour necrosis factor-alpha by blood monocytes and alveolar macrophages

The purpose of this study was to evaluate the effect of theophylline on tumour necrosis factor-alpha (TNF-alpha) release by human blood monocytes (BMo), and rat BMo and alveolar macrophages (AM). BMo and AM were incubated in the absence or presence of theophylline, and the cell-free supernatants were harvested and tested for TNF-alpha activity by bioassay. Theophylline dose-dependently reduced TNF-alpha release by human BMo: significant inhibition was observed at 100 microns (41 +/- 5.9% of controls) and at 50 microns (59 +/- 4.8% of controls), while the inhibitory activity of theophylline at 10 microns (71 +/- 8.9% of controls) was not statistically significant. This activity was maximal at 2 h and declined at 4 h (59 +/- 5.2% of controls) and 24 h (89 +/- 3.1% of controls). Northern analysis performed on ribonucleic acid (RNA) extracted from human BMo demonstrated that theophylline was able to reduce TNF-alpha gene expression. Comparable levels of inhibition of TNF-alpha release were observed on rat BMo and AM (rat BMo 42 +/- 4.9% of controls; rat AM 38 +/- 1.7% of controls), suggesting that BMo and AM are equally susceptible to suppression of TNF-alpha release induced by theophylline. These results indicate that theophylline suppresses TNF-alpha release by mononuclear phagocytes. Since TNF-alpha is involved in the pathogenesis of bronchial hyperresponsiveness and asthma, our results suggest that the therapeutic activity of theophylline might be partly related to its effect on TNF-alpha release.

Clinical Benefits of 7 Years of Treatment with Omalizumab in Severe Uncontrolled Asthmatics

Rationale. Severe asthma is characterized by inadequate symptom control and by high rate of inflammation despite high doses of steroids. Omalizumab, a recombinant humanized monoclonal anti-IgE, provides a new therapeutic strategy in severe allergic asthma. Aims. This study was aimed to assess whether long-term treatment with omalizumab improved clinical control in severe asthmatics. Methods. We investigated omalizumab effects on asthma outcomes evaluating seven severe allergic asthmatic patients who were treated for 7 years with add-on omalizumab. Number of exacerbations, use of antibiotics, additional asthma medications (systemic steroids, nebulized steroids and bronchodilators), and spirometry were analyzed before and after omalizumab treatment. Results. Omalizumab was well tolerated by all the studied patients. It improved FEV1 and FEV1/FVC ratio and reduced symptom score, asthma exacerbations, use of antibiotics, and use of nebulized steroids, bronchodilators, and oral corticosteroids. These effects were evident after 4 years of treatment and more pronounced after 7 years of treatment. Conclusions. This study underlines the utility of a long-term treatment with omalizumab to improve asthma clinical outcomes in severe asthmatics.

Variable p‐CREB expression depicts different asthma phenotypes

Background:  Chromatin modification may play a role in inflammatory gene regulation in asthma. Cyclic adenosine mono‐phosphate response element‐binding protein (CREB), with the specific co‐activator, the CREB‐binding protein (CBP), contributes to the acetylation of chromatin and to the transcription of pro‐inflammatory genes.