Effects of low doses of inhaled fluticasone propionate on inflammation and remodelling in persistent-mild asthma

Advances in asthma pathophysiology: stepping forward from the Maurizio Vignola experience

Maurizio Vignola was a superb and innovative researcher, who wrote seminal papers on the biology of airway epithelium in asthma. Inflammation and remodelling were the main topics of his research, mostly conducted in biopsy specimens from patients with asthma of variable severity, encompassing the entire spectrum of the disease from mild to severe asthma. His observations contributed to define the biology of asthma as we know it today, and opened the way to the personalised treatment of asthma. His group has successfully continued to investigate the biology and clinical aspects of bronchial asthma, with major interest in the clinical use of biomarkers to monitor disease activity, and in the development of new therapeutic perspectives. This review summarises the latest work on these topics proudly conducted by Maurizio's closest collaborators. The results indicate significant progress in our understanding of asthma in the last 10 years, in particular increased knowledge of the complex interaction between inflammatory and remodelling pathways, improved recognition of biological and clinical asthma phenotypes, and development of new treatment strategies, especially for patients with severe corticosteroid-resistant asthma.

Biomarkers may help to define disease phenotypes and new treatment strategies for asthmahttp://ow.ly/G2Fl6

Deregulation of apoptosis mediators' p53 and bcl2 in lung tissue of COPD patients

Abnormal apoptotic events in chronic obstructive pulmonary disease (COPD) subvert cellular homeostasis and may play a primary role in its pathogenesis. However, studies in human subjects are limited.

p53 and bcl2 protein expression was measured by western blot on lung tissue specimens from 43 subjects (23 COPD smokers and 20 non-COPD smokers), using beta-actin as internal control. Additionally, p53 and bcl2 expression patterns were evaluated by immunohistochemistry in formalin-fixed, paraffin-embedded lung tissue sections from the same individuals.

Western blot analysis showed statistically significant increased p53 protein levels in COPD smokers in comparison with non-COPD smokers (p = 0.038), while bcl2 protein levels were not statistically different between the two groups. Lung immunohistochemistry showed increased ratio of positive p53-stained type II pneumocytes/total type II pneumocytes in COPD smokers compared to non-COPD smokers (p = 0.01), whereas the p53 staining ratio in alveolar macrophages and in lymphocyte-like cells did not differ statistically between the two groups. On the other hand, bcl2 expression did not differ between the two groups in all three cell types.

The increased expression of pro-apoptotic p53 in type II pneumocytes of COPD patients not counterbalanced by the anti-apoptotic bcl2 could reflect increased apoptosis in the alveolar epithelium of COPD patients. Our results confirm previous experiments and support the hypothesis of a disturbance in the balance between the pro- and anti-apoptotic mediators in COPD.

Complexities of diagnosis and treatment of allergic respiratory disease in the elderly

Atopic diseases such as rhinitis and asthma are relatively common in children and young adults. However, many patients aged >65 years are also affected by these disorders. Indeed, the literature suggests that between 3-12% and 4-13% of individuals in this age range have allergic rhinitis and asthma, respectively. However, these numbers are most likely underestimates because atopic diseases are frequently not considered in older patients. The diagnosis of both allergic rhinitis and asthma in older patients is more difficult than in younger patients because of a wide differential diagnosis of other diseases that can produce similar symptoms and must be excluded. Furthermore, treatment of these disorders is complicated by the potential for drug interactions, concern about the adverse effects of medications, in particular corticosteroids, and the lack of drug trials specifically targeting treatment of older patients with allergic rhinitis and asthma.

Matrix metalloproteinase-9 (MMP-9) in allergic nasal polyps

Matrix metalloproteinases (MMPs) are known to play important roles in the invasion of nasal mucosa by inflammatory cells through degradation of extracellular matrix. Matrix metalloproteinase-9 (MMP-9) is considered to play a role in the pathogenesis of nasal polyp. The aim of the present study was to compare plasma MMP-9 levels of patients with nasal polyp of different etiologic origins, those with allergic nasal polyp (ANP) and non-allergic nasal polyp (NANP). In all, 29 patients (20 NANP and 9 ANP) and 20 healthy subjects were included in this study. Plasma MMP-9 levels were measured using ELISA. Plasma MMP-9 levels were higher (p<0.05) in ANP patients than in NANP patients and controls. In the group with ANP, plasma MMP-9 levels showed a positive correlation (p<0.05) with eosinophil counts. Plasma MMP-9 levels of NANP patients and control groups were similar (p>0.05). Moreover, that the highest levels of MMP-9 were in ANP patients may indicate the usefulness of this parameter in differentiating between the different etiologic origins of nasal polyp. Further studies are required to elaborate on the relationship between MMP-9 levels and allergic reactions.

Airway remodeling is correlated with obstruction in children with severe asthma

BACKGROUND

Severe asthma may involve an irreversible obstructive pattern, and structural changes in bronchial airways are believed to play a key role in this context. The aim of the present study was to compare airway remodeling in severe asthmatic children with or without obstructive pattern.

METHODS

Two groups of children with severe asthma and persistent symptoms, 5-14 years old were included, 15 with persistent obstructive pattern (group O) and 10 without obstructive pattern (group N). Persistent obstructive pattern was defined as a forced expiratory volume in 1 s (FEV(1)) less than 80% of the predicted value after a course of systemic corticosteroids and no significant improvement after bronchodilator. We examined bronchial biopsies by pathological and immunochemical methods and quantified airway smooth muscle (ASM) and mucus gland areas, reticular basement membrane (RBM) thickening, distance between ASM and RBM, muscle light chain kinase (MLCK) expression and number of vessels (CD31 expression).

RESULTS

Surface area of ASM (P = 0.009), MLCK expression (P = 0.03) and number of vessels (P = 0.0008) were increased in group O compared with group N. Distance of RBM-ASM was shorter in group O (P = 0.007). FEV(1) negatively correlated with ASM area (r = -0.6; P = 0.002), MLCK expression (r = -0.45; P = 0.02) and CD31 expression (r = -0.7; P = 0.0003), and positively correlated with the distance of RBM-ASM (r = 0.5; P = 0.007).

CONCLUSIONS

Structural abnormalities of airway remodeling are present in children with severe asthma. Only an increase in surface area of ASM and the density of the vascular network are more pronounced in children with persistent obstructive pattern, while RBM thickening is similar. These results are concordant with longitudinal studies which emphasize the precocity of bronchial obstruction.

Matrix metalloproteases in vernal keratoconjunctivitis, nasal polyps and allergic asthma

BACKGROUND

Allergic conditions in different organs share many similarities in their inflammatory response. Vernal keratoconjunctivitis (VKC), asthma and nasal polyps exhibit several similar, but site-specific mucosal structural changes. The aim of the study was to investigate whether matrix metalloproteases contribute to different tissue remodelling aspects in different organs.

METHODS

Mucosal biopsies were obtained from conjunctiva of healthy donors, tarsal conjunctiva of vernal patients, bronchi of non-asthmatic subjects, bronchi of mild stable asthmatic patients, nasal mucosa of non-allergic donors and nasal polyps of allergic patients. Distribution of metalloprotease-1, -3, -9, -13, tissue inhibitor of metalloproteases-1, collagens I and III and the presence of eosinophils and CD4+ cells were evaluated by immunohistochemistry.

RESULTS

Collagens were highly diffuse in the giant papillae of VKC and in nasal polyps, and yet less increased in the subepithelium of asthmatic patients. Immunostaining for metalloprotease-1, -3, -9 and -13 was significantly higher in VKC compared with normal conjunctiva. Metalloprotease-9 staining was higher in the stroma of polyps vs. normal nasal mucosa, and only metalloprotease-13 was significantly more expressed in asthmatic vs. non-asthmatic subjects. Metalloprotease-9 immunostaining was more intense in vernal compared with other tissues. In all pathological tissues, metalloprotease-9-positive staining was in association with eosinophils and CD4+ cells.

CONCLUSIONS

Expression of metalloproteases may play an important role in inducing the structural changes seen in VKC, nasal polyps and asthma. Tissue remodelling and gelatinase immunoexpression was more dramatic in giant papillae of vernal patients compared with other tissue sites of chronic allergic inflammation.

Daily versus intermittent corticosteroids for the treatment of mild persistent asthma

Asthma is a chronic disease of the airways in which inflammation causes bronchial hyper-reactivity and attacks of wheezing, dyspnea and chest tightness that are triggered by various agents. It requires both acute treatment of the paroxistical respiratory symptoms with reliever medications and maintenance treatment, which is aimed at achieving an optimal disease control and consists of controller medications with regimens and dosages that are tailored according to disease severity. Inhaled steroids represent the main controller medication and are recommended to be given even in mild asthma on a daily basis in order to improve lung function, reduce asthma exacerbations and symptoms, and improve the quality of life. Intermittent regimens could also be used and the currently discussed study compares these two regimens in terms of clinical efficacy.

Optimized dialysis and protease inhibition of sputum dithiothreitol supernatants

RATIONALE

Dithiothreitol (DTT) is commonly used to liquefy induced sputum samples before assessment of cytology, but causes reduction of disulfide bonds and denaturation of proteins.

OBJECTIVES

To process sputum supernatants containing DTT to enable quantification of cytokines and chemokines.

METHODS

A standard solution of 22 pooled chemokines and cytokines was incubated with DTT at the concentrations used during sputum liquefaction and then dialyzed under 20 different denaturant and redox conditions.

MEASUREMENTS AND MAIN RESULTS

After incubation of the standard solution with DTT there was loss of detectable protein mediators on immunoassay, but optimized dialysis permitted recovery of chemokines to 96 +/- 4% and cytokines to 91 +/- 6%. Optimized dialysis of DTT supernatants from subjects with asthma covering a range of severities (n = 35) was performed in the presence of a cocktail of protease inhibitors and demonstrated significantly elevated levels of the chemokine CXCL10 (IFN-gamma-inducible protein-10), CXCL8 (IL-8), and CCL3 (macrophage inflammatory protein-1alpha); with lower but significantly elevated levels of CCL2 (monocyte chemotactic protein-1), CCL11 (eotaxin), and CCL5 (regulated on activation, normal T-cell expressed and secreted) in severe asthma. In sputum from subjects with severe asthma there were also significantly elevated levels of IL-4, IL-5, IL-13, tumor necrosis factor-alpha, IL-6, granulocyte-macrophage colony-stimulating factor, and IL-12(p40).

CONCLUSIONS

The technique of optimized dialysis and protease inhibition of sputum DTT supernatants aids the detection of chemokines and cytokines. The detection of elevated levels of particular sputum chemokines and cytokines in individual patients may provide a rationale for specific therapies.

Airway remodeling and lack of bronchodilator response in steroid-resistant asthma

BACKGROUND

Steroid-resistant (SR) asthma is characterized by airway inflammation that fails to resolve despite treatment with corticosteroids, raising concerns that resistance to steroid therapy in asthma could lead to airway remodeling.

OBJECTIVE

We sought to determine whether SR asthma is accompanied by decreased airflow reversibility and could lead to airway remodeling.

METHODS

Spirometric results were evaluated for 40 asthmatic patients defined as having SR or steroid-sensitive (SS) asthma on the basis of a 1-week course of oral prednisone. Twenty-three asthmatic patients underwent bronchoscopy with collection of bronchoalveolar lavage (BAL) fluid to analyze markers of airway remodeling in BAL fluid and cells.

RESULTS

Prednisone significantly improved FEV(1) percent predicted in SS asthma (62.0% +/- 10.9% [mean +/- SD] to 79.4% +/- 11.3%, P < .001) but not in SR asthma (66.9% +/- 10.0% to 65.9% +/- 12.1%). The bronchodilator response was significantly greater in the SS than in the SR group (Delta FEV(1) percent predicted, 33.5% +/- 22.5% vs 15.2% +/- 7.9%; P = .001), regardless of inhaled corticosteroid use. No difference in amounts of matrix metalloproteinase (MMP) 9, PMN elastase, or vascular endothelial growth factor was found in BAL fluid from both groups. Tissue inhibitor of metalloproteinases (TIMP) 1 levels were, however, significantly less in BAL fluid of patients with SR asthma compared with those in patients with SS asthma (921.9 +/- 313.4 vs 2267.0 +/- 456.8 pg/mL, P < .05), resulting in significantly higher MMP-9/TIMP-1 ratios in the BAL fluid of patients with SR asthma (0.24 +/- 0.04 vs 0.11 +/- 0.03, P < .01). Finally, dexamethasone treatment induced TIMP-1 mRNA in BAL fluid cells from patients with SS asthma (P < .01) but not in cells from patients with SR asthma.

CONCLUSION

Bronchodilator reversibility is impaired in SR asthma and is associated with a shift in MMP-9/TIMP-1 ratio caused by inability of steroids to enhance TIMP-1 production, potentially promoting proteolytic activity in airways of patients with SR asthma and contributing to chronic airway remodeling.

CLINICAL IMPLICATIONS

SR asthma might lead to irreversible airways disease.

Mild asthma: an expert review on epidemiology, clinical characteristics and treatment recommendations

This review is the synthesis of a working group on mild asthma. Mild asthma includes intermittent and persistent mild asthma according to the Global Initiative for Asthma (GINA) classification, and affects between 50% and 75% of asthmatic patients. Mild asthma is more frequent, more symptomatic, and less well controlled in children than in adults. Cohort studies from childhood to adulthood show that asthma severity usually remains stable over time. Nevertheless, mild asthma can lead to severe exacerbations, with a frequency ranging from 0.12 to 0.77 per patient-year. Severe exacerbations in mild asthma represent 30-40% of asthma exacerbations requiring emergency consultation. In mild asthma, inflammation and structural remodelling are constant, of varying intensity, but nonspecific. Therapy with inhaled corticosteroids (ICS) decreases bronchial inflammation, but has only a slight effect on structural remodelling, and, when stopped, inflammation immediately recurs. Permanent low-dose ICS therapy is the reference treatment for persistent mild asthma. Effectiveness is to be reassessed at 3 months, and if it is insufficient the patient is no longer considered mildly asthmatic, and treatment has to be stepped up. As mild asthma is the most frequent form of the disease, diagnosis and management require physicians' particular attention.

The effect of inhaled budesonide and formoterol on bronchial remodeling and HRCT features in young asthmatics

Asthma is a chronic disease that may cause remodeling of the airways. We aimed to observe the effects of the combined use of inhaled budesonide and formoterol on both the reversibility of remodeling and structural changes in the airways. Thirty-six male patients (age range, 20-31) with mild-to-moderate persistent asthma were given inhaled formoterol and budesonide treatment for three months. Bronchial diameter (BD) and bronchial wall thickness (BWT), as measured by high-resolution computerized tomography, and reticular basement membrane thickness (RBMT), assessed in bronchoscopic biopsy specimens, were compared with pretreatment findings. Twenty-two age-matched male controls were also enrolled. BDs of the patients were significantly smaller than in the controls, whereas BWT and RBMT were greater. After three months BWT and RBMT of the subsegmental airways significantly decreased and BD increased. There was a prominent eosinophilic and lymphocytic infiltration in the bronchial mucosa of the asthmatics, and the eosinophilic infiltration significantly improved with treatment. Both serum total IgE and eosinophil counts were related to eosinophilic infiltration in the biopsy samples (r = 0.494 and r = 0.463, respectively). FEV(1) was positively correlated with the diameters of the segmental and subsegmental airways (r = 0.491 and r = 0.265, respectively) and negatively correlated with BWT of the subsegmental airways (r = -0.293) and with the RBMT of both the segmental and subsegmental airways (r = -0.597 and r = -0.590, respectively). We suggest that treatment with inhaled formoterol and budesonide may reverse increased RBMT and BWT as part of remodeling in patients with asthma.

Can we treat airway remodeling?

Asthma is a chronic disease that has been associated with structural changes of the airway wall. These changes lead to decreased reversibility of airway obstruction and have been understood as poorly reversible. Recent studies have proved that even some of the processes involved in airway remodeling may be reversible with early detection of the disease and appropriate anti inflammatory treatment. New treatments should be directed not only against inflammation itself but also against these chronic changes.