Relationships Among Bacteria, Upper Airway, Lower Airway, and Systemic Inflammation in COPD

Nasal biomarkers of immune function differ based on smoking and respiratory disease status

Respiratory biomarkers have the potential to identify airway injury by revealing inflammatory processes within the respiratory tract. Currently, there are no respiratory biomarkers suitable for clinical use to identify patients that warrant further diagnostic work-up, counseling, and treatment for toxic inhalant exposures or chronic airway disease. Using a novel, noninvasive method of sampling the nasal epithelial lining fluid, we aimed to investigate if nasal biomarker patterns could distinguish healthy nonsmoking adults from active smokers and those with chronic upper and lower airway disease in this exploratory study. We compared 28 immune mediators from healthy nonsmoking adults (n = 32), former smokers with COPD (n = 22), chronic rhinosinusitis (CRS) (n = 22), and smoking adults without airway disease (n = 13). Using ANOVA, multinomial logistic regressions, and weighted gene co-expression network analysis (WGCNA), we determined associations between immune mediators and each cohort. Six mediators (IL-7, IL-10, IL-13, IL-12p70, IL-15, and MCP-1) were lower among disease groups compared to healthy controls. Participants with lower levels of IL-10, IL-12p70, IL-13, and MCP-1 in the nasal fluid had a higher odds of being in the COPD or CRS group. The cluster analysis identified groups of mediators that correlated with disease status. Specifically, the cluster of IL-10, IL-12p70, and IL-13, was positively correlated with healthy and negatively correlated with COPD groups, and two clusters were correlated with active smoking. In this exploratory study, we preliminarily identified groups of nasal mucosal mediators that differed by airway disease and smoking status. Future prospective, age-matched studies that control for medication use are needed to validate these patterns and determine if nasosorption has diagnostic utility for upper and lower airway disease or injury.

A Systematic Review and Meta-Analysis of the Prevalence and Impact of Pulmonary Bacterial Colonisation in Stable State Chronic Obstructive Pulmonary Disease (COPD)

Background: Half of acute exacerbations of COPD are due to bacterial infection, and the other half are likely influenced by microbial colonisation. The same organisms commonly cultured during acute exacerbations are often found in the sputum of patients during stability. A robust assessment of the prevalence of potentially pathogenic microorganisms (PPMs) in the sputum of stable COPD patients may help to inform the targeted prevention of exacerbation by these organisms. Methods: A systematic review and meta-analysis was carried out to determine the prevalence of PPMs in patients with COPD in the stable state. Meta-analysis of prevalence was carried out using the Freeman–Tukey double arcsine transformation random effects model, and sub-group analysis was performed for sputum modality. Prevalence of total and individual PPMs was calculated from patient-level data from individual studies. Results: Pooled prevalence of PPMs identified by sputum culture was found to be 41% (95% CI 36–47%). Significant heterogeneity was found across all studies, which can likely be attributed to inconsistent measuring and reporting of PPMs. The most commonly reported organisms were H. influenzae, M catarrhalis, S. pneumoniae, S. aureus, and P. aeruginosa. Declining lung function was weakly correlated with prevalence of PPMs. Conclusion: The airways of patients with COPD are colonised with PPMs during the stable state in almost half of patients. A complex relationship likely exists between the microbiome in the stable state and the phenotype of COPD patients. Targeted microbial therapy for preventing exacerbations of COPD should carefully consider the stable microbiome as well as the exacerbated.

Influence of Hypoxia on the Epithelial-Pathogen Interactions in the Lung: Implications for Respiratory Disease

Under normal physiological conditions, the lung remains an oxygen rich environment. However, prominent regions of hypoxia are a common feature of infected and inflamed tissues and many chronic inflammatory respiratory diseases are associated with mucosal and systemic hypoxia. The airway epithelium represents a key interface with the external environment and is the first line of defense against potentially harmful agents including respiratory pathogens. The protective arsenal of the airway epithelium is provided in the form of physical barriers, and the production of an array of antimicrobial host defense molecules, proinflammatory cytokines and chemokines, in response to activation by receptors. Dysregulation of the airway epithelial innate immune response is associated with a compromised immunity and chronic inflammation of the lung. An increasing body of evidence indicates a distinct role for hypoxia in the dysfunction of the airway epithelium and in the responses of both innate immunity and of respiratory pathogens. Here we review the current evidence around the role of tissue hypoxia in modulating the host-pathogen interaction at the airway epithelium. Furthermore, we highlight the work needed to delineate the role of tissue hypoxia in the pathophysiology of chronic inflammatory lung diseases such as asthma, cystic fibrosis, and chronic obstructive pulmonary disease in addition to novel respiratory diseases such as COVID-19. Elucidating the molecular mechanisms underlying the epithelial-pathogen interactions in the setting of hypoxia will enable better understanding of persistent infections and complex disease processes in chronic inflammatory lung diseases and may aid the identification of novel therapeutic targets and strategies.

Early COPD: current evidence for diagnosis and management

Chronic obstructive pulmonary disease (COPD) affects one-tenth of the world's population and has been identified as a major global unmet health need by the World Health Organisation, which predicts that within 10 years, COPD will become the third leading cause of death. Despite active research, there have been no recent major strides in terms of disease modifying treatment for COPD; smoking cessation remains the only intervention known to alter disease progression and improve mortality. As established COPD is a key driver of disease burden, earlier diagnosis coupled with disease-modifying intervention carries promise as a route to address this global health priority. The concept of early COPD is emerging as an area of focus for research and consideration of new treatment modalities, as it has been hypothesised that intervention at this stage may potentially halt or reverse the disease process. However, at present, a globally accepted criteria for defining early COPD does not exist. Several studies propose small airways disease as the earliest stage in the development of COPD, and this has been demonstrated to be a precursor to development of emphysema and to correlate with subsequent development of airflow obstruction. However, treatment strategies for early disease, which pre-date the development of airflow obstruction, remain uncertain. This review addresses the rationale and current evidence base for the diagnosis and treatment of early COPD and highlights the challenges of implementing trials and clinical pathways to address COPD earlier in the life course, particularly in the absence of a universally accepted definition of COPD.The reviews of this paper are available via the supplemental material section.

Effect of Nasal Anti-Inflammatory Treatment in Chronic Obstructive Pulmonary Disease

Background

Sinonasal inflammation and symptoms are often underdiagnosed in chronic obstructive pulmonary disease (COPD) patients. So far, it is not known to what extent anti-inflammatory nasal treatment may reduce sinonasal symptoms in COPD patients. This study was designed to examine the effects of nasal anti-inflammatory treatment on sinonasal symptoms and cough in COPD patients.

Methods

Thirty-three COPD patients on stable bronchial therapy (salmeterol/fluticasone propionate 50/500 mg b.i.d. for >6 weeks) were randomized to receive fluticasone furoate (FF) or placebo nasal spray at 110 μg once daily for 12 weeks. Sinonasal symptoms and cough were monitored at baseline, at 6 and 12 weeks of treatment, and at 4 weeks after cessation of the treatment using a visual analog scale. Levels of cytokines were measured in nasal secretions.

Results

In contrast to the placebo group (n = 13), FF patients (n = 14) reported less nasal blockage (10.62 ± 4.21 mm versus 36.57 ± 8.01 mm; p = 0.0026), postnasal drip (1.46 ± 0.29 score versus 2.83 ± 0.38 score; p = 0.03), and nasal discharge (0.23 ± 0.12 score versus 1.77 ± 0.43 score; p = 0.01) after 6 weeks of treatment compared with baseline, which was still present at 12 weeks. FF patients reported less cough compared with baseline (25.54 ± 4.46 mm versus 36.79 ± 5.75 mm; p = 0.04), which was not the case in the placebo group (49.58 ± 10.44 mm versus 42.00 ± 8.05 mm; p = 0.38). Nine of 14 patients in the FF group (64%) reported slight to total relief of nasal symptoms, and this subgroup had a significant decrease in IL-8 levels in nasal secretions after 6 weeks of treatment (850.7 ± 207.2 pg/mL versus 1608 ± 696.5 pg/mL; p = 0.03) compared with baseline.

Conclusion

Nasal FF treatment in COPD patients significantly reduced sinonasal symptoms, in parallel with reduced IL-8 in nasal secretion levels and cough.

Airway Epithelial Cell Cilia and Obstructive Lung Disease

Airway epithelium is the first line of defense against exposure of the airway and lung to various inflammatory stimuli. Ciliary beating of airway epithelial cells constitutes an important part of the mucociliary transport apparatus. To be effective in transporting secretions out of the lung, the mucociliary transport apparatus must exhibit a cohesive beating of all ciliated epithelial cells that line the upper and lower respiratory tract. Cilia function can be modulated by exposures to endogenous and exogenous factors and by the viscosity of the mucus lining the epithelium. Cilia function is impaired in lung diseases such as COPD and asthma, and pharmacologic agents can modulate cilia function and mucus viscosity. Cilia beating is reduced in COPD, however, more research is needed to determine the structural-functional regulation of ciliary beating via all signaling pathways and how this might relate to the initiation or progression of obstructive lung diseases. Additionally, genotypes and how these can influence phenotypes and epithelial cell cilia function and structure should be taken into consideration in future investigations.

Chronic Obstructive Pulmonary Disease Predicts Chronic Rhinosinusitis without Nasal Polyps: A Population-Based Study

Background

Few studies have investigated the relationship between chronic obstructive pulmonary disease (COPD) and chronic rhinosinusitis without nasal polyps (CRSsNP) outcomes. The aim of this study was to investigate the association between COPD and the risk of CRSsNP in a large national sample.

Methods

Patients 15 years or older with a new primary diagnosis of COPD (International Classification of Diseases, Ninth edition [ICD-9], 491, 492, 494, and 496) between 2000 and 2007 were identified from the National Health Insurance Research Database of Taiwan. The patients were compared with sex-, age-, residence-, and insurance premium–matched controls, and both groups were followed up until the end of 2008 for instances of CRSsNP, defined as ICD-9 codes CRS (473, 473.0, 473.1, 473.2, 473.3, 473.8, and 473.9), excluding NP (471, 471.0, 471.1, 471.8, and 471.9). Competing risk-adjusted Cox regression analyses were applied after adjusting for sex, age, residence, insurance premium, steroid use (topical or systemic), hyperlipidemia, diabetes, hypertension, coronary artery disease, hospital admission days, and mortality.

Results

We included 34,029 cases and 34,029 matched controls in this study. Among the 68,058 subjects, 569 developed CRSsNP during a mean (standard deviation [SD]) follow-up period of 5.0 years (SD 2.2 years). COPD was an independent predictor of CRSsNP in the fully adjusted model (hazard ratio = 3.24; 95% CI = 2.65-3.96; p < 0.01).

Conclusion

COPD was associated with an increased risk of CRSsNP in this study population, independent of a number of potential confounding factors.

Nonallergic rhinitis and its association with smoking and lower airway disease: A general population study

BACKGROUND

The cause of nonallergic rhinitis (NAR) and its relation to lower airway disease remains unclear. The purpose of this study was to perform a descriptive analysis of the occurrence of rhinitis in a Danish general population with focus on NAR and its association with smoking and lower airway disease.

METHODS

A population-based, cross-sectional study conducted in Copenhagen, Denmark was performed. A random sample from the general population (n = 7931; age, 18-69 years) was invited to a general health examination including measurements of serum-specific immunoglobulin E (IgE) to common aeroallergens; 3471 (44%) persons were accepted. For further analysis, we divided the population into the following groups: (I) negative specific IgE and no rhinitis (controls); (II) negative specific IgE and rhinitis (NAR); (III) positive specific IgE and rhinitis (allergic rhinitis [AR]); and (IV) positive specific IgE but no rhinitis (sensitized).

RESULTS

We found that NAR was associated with asthma (odds ratio [OR] = 2.51 [1.87-3.37]); chronic bronchitis (OR = 2.27 [1.85-2.79]); current smoking (>15 g/day; OR = 1.57 [1.18-2.08]); lower forced expiratory volume in 1 second/forced vital capacity (FEV(1)/FVC) ratios and reduced FEV(1) values. The association with chronic bronchitis was stronger in NAR than in AR, whereas the opposite was true for asthma. FEV(1)/FVC of <70% was not significantly associated to any group.

CONCLUSION

This epidemiological study indicates that both asthma and chronic bronchitis are important comorbidities in NAR confirming the "united airway" hypothesis, and that smoking might be a significant modulator of disease. Although NAR was significantly associated with poor lung function, no significant association with chronic obstructive pulmonary disease was shown.

COPD: a multifactorial systemic disease

Chronic obstructive pulmonary disease (COPD) has traditionally been considered a disease of the lungs secondary to cigarette smoking and characterized by airflow obstruction due to abnormalities of both airway (bronchitis) and lung parenchyma (emphysema). It is now well known that COPD is associated with significant systemic abnormalities, such as renal and hormonal abnormalities, malnutrition, muscle wasting, osteoporosis, and anemia. However, it is still unclear whether they represent consequences of the pulmonary disorder, or whether COPD should be considered as a systemic disease. These systemic abnormalities have been attributed to an increased level of systemic inflammation. Chronic inflammation, however, may not be the only cause of the systemic effects of COPD. Recent data from humans and animal models support the view that emphysema may be a vascular disease. Other studies have highlighted the role of repair failure, bone marrow abnormality, genetic and epigenetic factors, immunological disorders and infections as potential causes of COPD systemic manifestations. Based on this new evidence, it is reasonable to consider COPD, and emphysema in particular, as 'a disease with a significant systemic component' if not a 'systemic disease' per se. The aim of this review is to give an overview of the most relevant and innovative hypothesis about the extrapulmonary manifestations of COPD.