Elevated peripheral airway nitric oxide in bronchiectasis reflects disease severity

Bronchiectasis management in adults: state of the art and future directions

Formerly regarded as a rare disease, bronchiectasis is increasingly recognised. A renewed interest in this disease has led to significant progress in bronchiectasis research. Randomised clinical trials (RCTs) have demonstrated the benefits of airway clearance techniques, inhaled antibiotics and long-term macrolide therapy in bronchiectasis patients. However, the heterogeneity of bronchiectasis remains one of the most challenging aspects of management. Phenotypes and endotypes of bronchiectasis have been identified to help find "treatable traits" and partially overcome disease complexity. The goals of therapy for bronchiectasis are to reduce the symptom burden, improve quality of life, reduce exacerbations and prevent disease progression. We review the pharmacological and non-pharmacological treatments that can improve mucociliary clearance, reduce airway inflammation and tackle airway infection, the key pathophysiological features of bronchiectasis. There are also promising treatments in development for the management of bronchiectasis, including novel anti-inflammatory therapies. This review provides a critical update on the management of bronchiectasis focusing on treatable traits and recent RCTs.

Clinical Values of Nitric Oxide Parameters from the Respiratory System

BACKGROUND

Fractional exhaled nitric oxide (FENO) concentration reliably reflects central airway inflammation, but it is not sensitive to changes in the NO dynamics in the lung periphery. By measuring FENO at several different flow rates one can estimate alveolar NO concentration (C_ANO), bronchial NO flux (J_awNO), bronchial wall NO concentration (C_awNO) and the bronchial diffusivity of NO (D_awNO).

OBJECTIVE

We aimed to describe the current knowledge and clinical relevance of NO parameters in different pulmonary diseases.

METHODS

We conducted a systematic literature search to identify publications reporting NO parameters in subjects with pulmonary or systemic diseases affecting the respiratory tract. A narrative review was created for those with clinical relevance.

RESULTS

Estimation of pulmonary NO parameters allows for differentiation between central and peripheral inflammation and a more precise analysis of central airway NO output. C_ANO seems to be a promising marker of parenchymal inflammation in interstitial lung diseases and also a marker of tissue damage and altered gas diffusion in chronic obstructive pulmonary disease and systemic diseases affecting the lung. In asthma, C_ANO can detect small airway involvement left undetected by ordinary FENO measurement. Additionally, C_awNO and D_awNO can be used in asthma to assess if FENO is increased due to enhanced inflammatory activity (increased C_awNO) or tissue changes related to bronchial remodelling (altered D_awNO).

CONCLUSION

NO parameters may be useful for diagnosis, prediction of disease progression and prediction of treatment responses in different parenchymal lung and airway diseases. Formal trials to test the added clinical value of NO parameters are needed.

Clinical features associated with a doctor-diagnosis of bronchiectasis in the Severe Asthma Network in Italy (SANI) registry

BACKGROUND

Several severe asthma comorbidities have been identified: an emerging one is bronchiectasis. We evaluated the frequency of bronchiectasis on severe asthma in a real-life setting, through the 'Severe Asthma Network Italy' (SANI) registry.

METHODS

SANI registry encompasses demographic, clinical, functional and inflammatory data of Italian severe asthmatics. Data obtained by the enrolled patients were analyzed, focusing the attention on those patients with concomitant clinically relevant bronchiectasis.

RESULTS

About 15.5% patients have bronchiectasis. Bronchiectasis diagnosis was associated with a higher prevalence of chronic rhinosinusitis with nasal polyps (54.6% vs. 38%, p = 0.001) and higher serum IgE levels (673.4 vs. 412.1 kUI/L, p = 0.013). Patients with bronchiectasis had worse asthma control (ACT: 16.7 vs 18.2, p = 0.013), worse quality of life (AQLQ: 4.08 vs. 4.60, p = 0.02) and lower lung function (FEV₁% predicted 67.3 vs. 75.0, p = 0.002). A higher rate of severe asthma exacerbations in the previous 12 months (85.2% vs. 61.5%, p < 0.001) was found in patients with bronchiectasis.

CONCLUSION

severe asthma associated with bronchiectasis represents a particularly severe asthma variant, possibly driven by an eosinophilic endotype. We, therefore, suggest that bronchiectasis should necessarily be assessed in severe asthmatic patients.

The role of non-invasive modalities for assessing inflammation in patients with non-cystic fibrosis bronchiectasis

INTRODUCTION

Bronchiectasis is a heterogeneous entity, taking into account clinical characteristics, inflammatory response, effectiveness of treatment and frequency of exacerbations. In stable state non-cystic fibrosis (non-CF) bronchiectasis, little is known about non-invasive techniques used for evaluating airway inflammation in obstructive airway diseases.

OBJECTIVES

We sought to evaluate the associations between induced sputum and clinical/radiologic characteristics, and the differences between biomarkers expressing Th1 and Th2 response in patients with non-CF bronchiectasis and to compare our findings with a previously studied population of patients with asthma and COPD.

METHODS

We evaluated prospectively collected data from subjects with bronchiectasis. Comparisons were made between clinical, radiographic and physiologic characteristics, as well as induced sputum markers using appropriate statistical tools. We compared the levels of sputum markers with those of a previously studied cohort of asthma and COPD patients.

RESULTS

We enrolled 40 subjects (21men, mean age 63.5yrs) with bronchiectasis. Fifteen subjects (37.5%) had a neutrophilic phenotype, 7 (17.5%) had an eosinophilic phenotype, 3 (12.5%) had a mixed neutrophilic-eosinophilic phenotype and 15 (37.5%) had a paucigranulocytic phenotype. Subjects with sputum neutrophilia had more severe bronchiectasis in HRCT and higher levels of IL-8 in sputum, whereas subjects with eosinophilia had higher levels of FeNO, greater bronchodilator reversibility and higher sputum IL-13. Sputum IL-8 levels were higher in subjects exhibiting frequent exacerbations and correlated with neutrophils in sputum (r=0.799), the extent of bronchiectasis in HRCT (r=0.765) and post-bronchodilator FEV₁ (r=-0.416). Sputum IL-13 levels correlated with sputum eosinophils (r=0.656) and bronchodilator reversibility (r=0.441). Neutrophilic bronchiectasis exhibited comparable IL-8 levels to COPD, whereas eosinophilic bronchiectasis showed significantly lower IL-13 levels compared to asthma.

CONCLUSIONS

Sputum cell counts and IL-8 and IL-13 correlate with distinct clinical and functional measurements of disease severity and therefore may have a role for non-invasively assessing inflammation in non-cystic fibrosis bronchiectasis.

Advanced diagnostic studies: exhaled breath and sputum analyses

AIM

: The present paper aims to review the advantages and limitations of sputum cell counts and exhaled nitric oxide (FeNO) levels in the investigation of occupational asthma (OA).

METHODS

The American College of Chest physicians held a course on occupational and Environmental Lung Diseases in Toronto in 2013. A summary of the session on non-invasive measures of airway inflammation in OA is presented here.

RESULTS

Occupational asthma is associated with an increase in sputum eosinophil percentage during periods at work or after positive specific inhalation challenges. Changes in FeNO are less sensitive than sputum eosinophil counts for predicting OA.

CONCLUSIONS

In settings where this tool is available, sputum eosinophil counts may complement the current investigation of OA. The interpretation of FeNO remains sometimes difficult. The phenotypes of patients who may benefit from this measure needs to be better defined.

Neutrophil elastase gene polymorphisms: modulators of response to therapy in childhood bronchiectasis?

BACKGROUND

The aim of this study was to investigate polymorphisms in the promoter region of the neutrophil elastase (ELANE) gene as potential modulators of the therapeutic response in children with idiopathic bronchiectasis.

METHODS

The study included 48 children between 5 and 17 years old who were diagnosed with idiopathic bronchiectasis based on high-resolution computed tomography of the thorax. In all patients therapy included administration of antibiotics, anti-inflammatory drugs, expectorants, and postural drainage. Response to therapy was evaluated by the change in FeNO levels before and after administration of therapy. The ELANE promoter region polymorphisms were analyzed by PCR-direct DNA sequencing.

RESULTS

According to the predicted activity of ELANE genotypes, subjects were divided into two groups: low/intermediate activity (n = 18) and high activity (n = 30). Subjects in the group with high-activity genotype had higher initial FeNO levels and this difference was statistically significant (t = 2.906; p = 0.006). The difference between FeNO levels before and after therapy was also statistically significantly higher in children with high-activity genotype (t = 3.329; p = 0.002). Statistically significant correlation was observed between the change in FeNO levels and ELANE genotypes (r = 0.350; p = 0.015).

CONCLUSION

Children with high-activity genotype had higher initial FeNO levels and showed better response to therapy than children with low/intermediate-activity genotypes.

Measurement of fractional exhaled nitric oxide in stable bronchiectasis

Background

Fractional exhaled nitric oxide (FeNO) can be measured easily, rapidly, and noninvasively for the assessment of airway inflammation, particularly mediated by eosinophil, such as asthma. In bronchiectasis (BE), the pathogenesis has been known as chronic airway inflammation and infection with abnormal airway dilatation; however, there are little studies to evaluate the role of FeNO in BE.

Methods

From March 2010 to February 2012, 47 patients with BE, diagnosed by high resolution computed tomography (HRCT), performed FeNO, compared with asthma and chronic obstructive pulmonary disease (COPD). All patients carried out a complete blood count including eosinophil count, chemistry, sputum examination, and spirometry, if indicated. A retrospective analysis was performed to elucidate the clinical role of FeNO in BE patients.

Results

The mean FeNO levels in patients with BE was 18.8±1.5 part per billion (ppb), compared to 48.0±6.4 and 31.0±4.3 in those with asthma and COPD, respectively (p<0.001). The FeNO levels tended to increase along with the disease severity scores by HRCT; however, it was statistically not significant. FeNO in BE with a co-infection of nontuberculous mycobacteria was the lowest at 17.0±3.5 ppb among the study population.

Conclusion

FeNO in BE was lower than other chronic inflammatory airway diseases, particularly compared with asthma. For clinical application of FeNO in BE, more large-scaled, prospective studies should be considered.

Clinical application of exhaled nitric oxide measurement in pediatric lung diseases

Fractional exhaled nitric oxide (FeNO) is a non invasive method for assessing the inflammatory status of children with airway disease. Different ways to measure FeNO levels are currently available. The possibility of measuring FeNO levels in an office setting even in young children, and the commercial availability of portable devices, support the routine use of FeNO determination in the daily pediatric practice. Although many confounding factors may affect its measurement, FeNO is now widely used in the management of children with asthma, and seems to provide significantly higher diagnostic accuracy than lung function or bronchial challenge tests. The role of FeNO in airway infection (e.g. viral bronchiolitis and common acquired pneumonia), in bronchiectasis, or in cases with diffuse lung disease is less clear. This review focuses on the most recent advances and the current clinical applications of FeNO measurement in pediatric lung disease.

The immune response and its therapeutic modulation in bronchiectasis

Bronchiectasis (BC) is a chronic pulmonary disease with tremendous morbidity and significant mortality. As pathogen infection has been advocated as a triggering insult in the development of BC, a central role for the immune response in this process seems obvious. Inflammatory cells are present in both the airways as well as the lung parenchyma, and multiple mediators of immune cells including proteases and cytokines or their humoral products are increased locally or in the periphery. Interestingly, a defect in the immune system or suppression of immune response during conditions such as immunodeficiency may well predispose one to the devastating effects of BC. Thus, the outcome of an active immune response as detrimental or protective in the pathogenesis of BC may be dependent on the state of the patient's immunity, the severity of infection, and the magnitude of immune response. Here we reassess the function of the innate and acquired immunity in BC, the major sites of immune response, and the nature of the bioactive mediators. Furthermore, the potential link(s) between an ongoing immune response and structural alterations accompanying the disease and the success of therapies that can modulate the nature and extent of immune response in BC are elaborated upon.