Current Challenges in Chronic Bronchial Infection in Patients with Chronic Obstructive Pulmonary Disease

Poly(sebacic acid) microparticles loaded with azithromycin as potential pulmonary drug delivery system: Physicochemical properties, antibacterial behavior, and cytocompatibility studies

Recurrent bacterial infections are a common cause of death for patients with cystic fibrosis and chronic obstructive pulmonary disease. Herein, we present the development of the degradable poly(sebacic acid) (PSA) microparticles loaded with different concentrations of azithromycin (AZ) as a potential powder formulation to deliver AZ locally to the lungs. We characterized microparticle size, morphology, zeta potential, encapsulation efficiency, interaction PSA with AZ and degradation profile in phosphate buffered saline (PBS). The antibacterial properties were evaluated using the Kirby-Bauer method against Staphylococcus aureus. Potential cytotoxicity was evaluated in BEAS-2B and A549 lung epithelial cells by the resazurin reduction assay and live/dead staining. The results show that microparticles are spherical and their size, being in the range of 1-5 μm, should be optimal for pulmonary delivery. The AZ encapsulation efficiency is nearly 100 % for all types of microparticles. The microparticles degradation rate is relatively fast - after 24 h their mass decreased by around 50 %. The antibacterial test showed that released AZ was able to successfully inhibit bacteria growth. The cytotoxicity test showed that the safe concentration of both unloaded and AZ-loaded microparticles was equal to 50 μg/ml. Thus, appropriate physicochemical properties, controlled degradation and drug release, cytocompatibility, and antibacterial behavior showed that our microparticles may be promising for the local treatment of lung infections.

Isolation of Pseudomonas aeruginosa in Stable Chronic Obstructive Pulmonary Disease Patients-Should We Treat It?

Chronic obstructive pulmonary disease (COPD) is one of the most frequent inflammatory diseases of the airways [...].

The Impact of Chronic Bronchial Infection in COPD: A Proposal for Management

Up to 50% of patients with chronic obstructive pulmonary disease (COPD) in stable state may carry potentially pathogenic microorganisms (PPMs) in their airways. The presence of PPMs has been associated with increased symptoms, increased risk and severity of exacerbations, a faster decline in lung function and impairment in quality of life. Although some clinical trials have demonstrated a reduction in exacerbations in patients chronically treated with systemic antibiotics, particularly macrolides, the selection of patients was based on the previous frequency of exacerbations and not on the presence of PPMs in their airways. Therefore, unlike in bronchiectasis, there is a lack of evidence-based recommendations for assessment and treatment of the presence of PPMs in either single or repeated isolations in COPD. In this article, we propose that chronic bronchial infection (CBI) in COPD be defined as the isolation of the same PPM in at least three sputum samples separated by more than one month; we review the impact of CBI on the natural course of COPD and suggest a course of action in patients with a single isolation of a PPM or suspected CBI. Antibiotic treatment in stable COPD should be recommended based on four main criteria: a) the presence of comorbid bronchiectasis, b) the demonstration of a single or multiple isolation of the same PPM, c) the clinical impact of CBI on the patients, and d) the type of PPM, either Pseudomonas aeruginosa or non-pseudomonal PPM. These recommendations are derived from evidence generated in patients with bronchiectasis and, until new evidence specifically obtained in COPD is available, they may help in the management of these challenging patients with COPD. Existing evidence suggests that inhaled therapy is insufficient to manage patients with moderate-to-severe COPD, frequent exacerbations, and CBI. New studies must be conducted in this particularly demanding population.

Decalogue for the selection of oral antibiotics for lower respiratory tract infections

Lower respiratory tract infections, including chronic obstructive pulmonary disease exacerbations (COPD-E) and community acquired pneumonia (CAP), are one of the most frequent reasons for consultation in primary care and hospital emergency departments, and are the cause of a high prescription of antimicrobial agents. The selection of the most appropriate oral antibiotic treatment is based on different aspects and includes to first consider a bacterial aetiology and not a viral infection, to know the bacterial pathogen that most frequently cause these infections and the frequency of their local antimicrobial resistance. Treatment should also be prescribed quickly and antibiotics should be selected among those with a quicker mode of action, achieving the greatest effect in the shortest time and with the fewest adverse effects (toxicity, interactions, resistance and/or ecological impact). Whenever possible, antimicrobials should be rotated and diversified and switched to the oral route as soon as possible. With these premises, the oral treatment guidelines for mild or moderate COPD-E and CAP in Spain include as first options beta-lactam antibiotics (amoxicillin and amoxicillin-clavulanate and cefditoren), in certain situations associated with a macrolide, and relegating fluoroquinolones as an alternative, except in cases where the presence of Pseudomonas aeruginosa is suspected.

Long-Term Risk of Mortality Associated with Isolation of Pseudomonas aeruginosa in COPD: A Systematic Review and Meta-Analysis

Background

Chronic bronchial infection is frequent in chronic obstructive pulmonary disease (COPD), but the impact of the isolation of pathogenic bacteria, and in particular Pseudomonas aeruginosa (PA) in respiratory samples on the prognosis of COPD is unclear.

Methods

We conducted a systematic review of prognostic studies including patients with isolation of PA in sputum in stable state or during exacerbations of COPD. The main outcomes were all-cause mortality, respiratory mortality, and number and severity of future exacerbations. Data were expressed as hazard ratio (HR) (95% confidence interval [CI]) whenever possible.

Results

Of 2773 studies, eight were finally included (23,228 individuals). The mean age ranged from 65.5 to 73 years. Six studies reported data for all-cause mortality. The adjusted risk of death was almost double in patients with PA isolation (HR 1.95, 95% CI, 1.34 to 2.84; quality of evidence moderate). Patients with PA isolation showed a three times higher adjusted risk of readmission at 30 days after discharge (OR 3.60, 95% CI, 3.60 to 12.03, 1 study; quality of evidence very low), and more than double adjusted risk of death and hospitalization at two years (HR 2.80, 95% CI, 2.20 to 3.56, 1 study; quality of evidence very low).

Conclusion

There is moderate certainty that the isolation of PA in sputum is associated with an adjusted increased risk of death in patients with COPD.

Spanish COPD Guidelines (GesEPOC) 2021: Updated Pharmacological treatment of stable COPD

The Spanish COPD Guidelines (GesEPOC) were first published in 2012, and since then have undergone a series of updates incorporating new evidence on the diagnosis and treatment of COPD. GesEPOC was drawn up in partnership with scientific societies involved in the treatment of COPD and the Spanish Patients' Forum. Their recommendations are based on an evaluation of the evidence using GRADE methodology, and a narrative description of the evidence in areas in which GRADE cannot be applied. In this article, we summarize the recommendations on the pharmacological treatment of stable COPD based on 9 PICO questions. COPD treatment is a 4-step process: 1) diagnosis, 2) determination of the risk level, 3) initial and subsequent inhaled therapy, and 4) identification and management of treatable traits. For the selection of inhaled therapy, high-risk patients are divided into 3 phenotypes: non-exacerbator, eosinophilic exacerbator, and non-eosinophilic exacerbator. Some treatable traits are general and should be investigated in all patients, such as smoking or inhalation technique, while others affect severe patients in particular, such as chronic hypoxemia and chronic bronchial infection. COPD treatment is based on long-acting bronchodilators with single agents or in combination, depending on the patient's risk level. Eosinophilic exacerbators must receive inhaled corticosteroids, while non-eosinophilic exacerbators require a more detailed evaluation to choose the best therapeutic option. The new GesEPOC also includes recommendations on the withdrawal of inhaled corticosteroids and on indications for alpha-1 antitrypsin treatment. GesEPOC offers a more individualized approach to COPD treatment tailored according to the clinical characteristics of patients and their level of complexity.

Development and multimodal characterization of an elastase-induced emphysema mouse disease model for the COPD frequent bacterial exacerbator phenotype

Chronic obstructive pulmonary disease (COPD) patients undergo infectious exacerbations whose frequency identifies a clinically meaningful phenotype. Mouse models have been mostly used to separately study both COPD and the infectious processes, but a reliable model of the COPD frequent exacerbator phenotype is still lacking. Accordingly, we first established a model of single bacterial exacerbation by nontypeable Haemophilus influenzae (NTHi) infection on mice with emphysema-like lesions. We characterized this single exacerbation model combining both noninvasive in vivo imaging and ex vivo techniques, obtaining longitudinal information about bacterial load and the extent of the developing lesions and host responses. Bacterial load disappeared 48 hours post-infection (hpi). However, lung recovery, measured using tests of pulmonary function and the disappearance of lung inflammation as revealed by micro-computed X-ray tomography, was delayed until 3 weeks post-infection (wpi). Then, to emulate the frequent exacerbator phenotype, we performed two recurrent episodes of NTHi infection on the emphysematous murine lung. Consistent with the amplified infectious insult, bacterial load reduction was now observed 96 hpi, and lung function recovery and disappearance of lesions on anatomical lung images did not happen until 12 wpi. Finally, as a proof of principle of the use of the model, we showed that azithromycin successfully cleared the recurrent infection, confirming this macrolide utility to ameliorate infectious exacerbation. In conclusion, we present a mouse model of recurrent bacterial infection of the emphysematous lung, aimed to facilitate investigating the COPD frequent exacerbator phenotype by providing complementary, dynamic information of both infectious and inflammatory processes.

Treatable Traits in COPD - A Proposed Approach

The well-recognized individual heterogeneity within COPD patients has led to a growing interest in greater personalization in the approach of these patients. Thus, the treatable traits strategy has been proposed as a further step towards precision medicine in the management of chronic airway disease, both in stable phase and acute exacerbations. The aim of this paper is to perform a critical review on the treatable traits strategy and propose a guide to approach COPD patients in the light of this new concept. An innovative stepwise approach is proposed - a multidisciplinary model based on two distinct phases, with the potential to be implemented in both primary care and hospital settings. The first phase is the initial and focused assessment of a selected subset of treatable traits, which should be addressed in all COPD patients in both settings (primary care and hospital). As some patients may present with advanced disease at diagnosis or may progress despite this initial treatment requiring a more specialized assessment, they should progress to a second phase, in which a broader approach is recommended. Beyond stable COPD, we explore how the treatable traits strategy may be applied to reduce the risk of future exacerbations and improve the management of COPD exacerbations. Since many treatable traits have already been related to exacerbation risk, the strategy proposed here represents an opportunity to be proactive. Although it still lacks prospective validation, we believe this is the way forward for the future of the COPD approach.

The Effects of Inhaled Airway Directed Pharmacotherapy on Decline in Lung Function Parameters Among Indigenous Australian Adults With and Without Underlying Airway Disease

BACKGROUND

The trajectory of lung function decline among Indigenous patients with or without underlying chronic airway disease (COPD and concomitant bronchiectasis) and with use of inhaled pharmacotherapy, including inhaled corticosteroids (ICS), has not been reported in the past.

METHODS

Adult Indigenous Australian patients identified to have undergone at least two or more lung function tests (LFTs) between 2012 and 2020 were assessed for changes in the lung function parameters (LFPs) between the first and last recorded LFTs.

RESULTS

Of the total 1350 patients identified to have undergone LFTs, 965 were assessed to fulfil session quality, 115 (n=58 females) were eligible to be included with two or more LFTs. Among the 115 patients, 49% showed radiological evidence of airway diseases, and 77% were on airway directed inhaled pharmacotherapy. Median time between LFTs was 1.5 years (IQR 0.86,5.85), with no significant differences in LFPs noted between first and last LFT. Overall rate of change (mL/year) showed considerable variation for FVC (median -37.55 mL/year [IQR -159.88,92.67]) and FEV1 (-18.74 mL/year [-102.49,71.44]) with minimal change in FEV1/FVC (0.00 ratio/year [-0.03,0.01]). When stratified by inhaled pharmacotherapy group, however, patients using ICS showed significantly greater rate of FEV1 decline (-48.64 mL/year [-110.18,62.5]) compared to those using pharmacotherapy with no ICS (15.46 mL/year [-73.5,74.62]) and those using no pharmacotherapy (-5.76 mL/year [-63.19,67.34]) (p=0.022). Additionally, a greater proportion of these patients reached the threshold for excessive FEV1 decline (64%) compared to those using pharmacotherapy without ICS (44%) and those using no pharmacotherapy (52%).

CONCLUSION

Decline in LFPs occurs commonly among adult Indigenous population, especially, excessive so among those using inhaled pharmacotherapy containing ICS.

Step-Up and Step-Down Treatment Approaches for COPD: A Holistic View of Progressive Therapies

Recent advances in inhaled drugs and a clearer definition of the disease have made the task of managing COPD more complex. Different proposals have been put forward which combine all the available treatments and the different clinical presentations in an effort to select the best therapeutic options for each clinical context. As COPD is a chronic progressive disease, the escalation of therapy has traditionally been considered the most natural way to tackle it. However, the notion of COPD as a constantly progressing disease has recently been challenged and, in specific areas, this points to the possibility of a de-escalation in treatment. In this context, the clinician requires simple, specific recommendations to guide these changes in treatment in their daily clinical practice. To accomplish this, the first step must be a correct evaluation and an accurate initial preliminary diagnosis of the patient's condition. Thereafter, the first escalation in therapy must be introduced with caution as the disease progresses, since clinical trials are not designed with clinical decision-making in mind. During this escalation, three possibilities are open to change the current treatment for a different one within the same family, to increase non-pharmacological interventions or to increase the pharmacological therapies. Beyond that point, a patient with persistent symptoms represents a complex clinical scenario which requires a specialized approach, including the evaluation of different respiratory and non-respiratory comorbidities. Unfortunately, there are few de-escalation studies available, and these are mainly observational in nature. The debate on de-escalation in pharmacological treatment, therefore, involves two main discussion points: the withdrawal of bronchodilators and the withdrawal of inhaled steroids. Altogether, the scheme for modifying treatment must be more personalized than just adding molecules, and the therapeutic response and its conditioning factors should be evaluated at each step before proceeding further.

AIM2 nuclear exit and inflammasome activation in chronic obstructive pulmonary disease and response to cigarette smoke

Introduction

The role inflammasomes play in chronic obstructive pulmonary disease (COPD) is unclear. We hypothesised that the AIM2 inflammasome is activated in the airways of COPD patients, and in response to cigarette smoke.

Methods

Lung tissue, bronchoscopy-derived alveolar macrophages and bronchial epithelial cells from COPD patients and healthy donors; lungs from cigarette smoke-exposed mice; and cigarette smoke extract-stimulated alveolar macrophages from healthy controls and HBEC30KT cell line were investigated. AIM2 inflammasome activation was assessed by multi-fluorescence quantitative confocal microscopy of speck foci positive for AIM2, inflammasome component ASC and cleaved IL-1β. Subcellular AIM2 localization was assessed by confocal microscopy, and immunoblot of fractionated cell lysates. Nuclear localization was supported by in-silico analysis of nuclear localization predicted scores of peptide sequences. Nuclear and cytoplasmic AIM2 was demonstrated by immunoblot in both cellular fractions from HBEC30KT cells.

Results

Increased cytoplasmic AIM2 speck foci, colocalized with cleaved IL-1β, were demonstrated in COPD lungs (n = 9) vs. control (n = 5), showing significant positive correlations with GOLD stages. AIM2 nuclear-to-cytoplasmic redistribution was demonstrated in bronchiolar epithelium in cigarette-exposed mice and in HBEC30KT cells post 24 h stimulation with 5% cigarette smoke extract. Alveolar macrophages from 8 healthy non-smokers responded to cigarette smoke extract with an > 8-fold increase (p < 0.05) of cytoplasmic AIM2 and > 6-fold increase (p < 0.01) of colocalized cleaved IL-1β speck foci, which were also localized with ASC.

Conclusion

The AIM2 inflammasome is activated in the airway of COPD patients, and in response to cigarette smoke exposure, associated with a nuclear to cytoplasmic shift in the distribution of AIM2.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12950-021-00286-4.

Effectiveness and Safety of Inhaled Antibiotics in Patients With Chronic Obstructive Pulmonary Disease. A Multicentre Observational Study

BACKGROUND

We aimed to describe the effectiveness and safety of inhaled antibiotics in chronic obstructive pulmonary disease (COPD) patients, as well as the patient profile in which they are usually prescribed and the patient groups that can most benefit from this treatment.

METHODS

Multicentre retrospective observational cohort study in COPD patients who had received ≥1 dose of inhaled antibiotics in the last 5 years. Clinical data from the two years prior to and subsequent to the start of the treatment were compared.

PRIMARY OUTCOME

COPD exacerbations.

SECONDARY OUTCOMES

side effects, symptomatology (sputum purulence, dyspnoea), microbiological profile and pathogen eradication.

RESULTS

Of 693 COPD patients analyzed (aged 74.1; 86.3% men; mean FEV₁=43.7%), 71.7% had bronchiectasis and 46.6% presented chronic bronchial infection (CBI) by Pseudomonas aeruginosa (PA). After 1 year of treatment with inhaled antibiotics, there was a significant decrease in the number of exacerbations (-33.3%; P<.001), hospital admissions (-33.3%; P<.001) and hospitalization days (-26.2%; P=.003). We found no difference in effectiveness between patients with or without associated bronchiectasis. Positive patient outcomes were more pronounced in PA-eradicated patients. We found a significant reduction in daily expectoration (-33.1%; P=.024), mucopurulent/purulent sputum (-53.9%; P<.001), isolation of any potentially pathogenic microorganisms (PPM) (-16.7%; P<.001), CBI by any PPM (-37.4%; P<.001) and CBI by PA (-49.8%; P<.001). CBI by any PPM and ≥three previous exacerbations were associated with a better treatment response. 25.4% of patients presented non-severe side-effects, the most frequent of these being bronchospasm (10.5%), dyspnoea (8.8%) and cough (1.7%).

CONCLUSIONS

In COPD patients with multiple exacerbations and/or CBI by any PPM (especially PA), inhaled antibiotics appear to be an effective and safe treatment, regardless of the presence of bronchiectasis.

Comorbid Conditions in Chronic Obstructive Pulmonary Disease: Potential Therapeutic Targets for Unmet Needs

The management of chronic obstructive pulmonary disease (COPD) has improved significantly due to advances in therapeutic agents, but it has also become apparent that there are issues that remain difficult to solve with the current treatment algorithm. COPD patients face a number of unmet needs concerning symptoms, exacerbations, and physical inactivity. There are various risk factors and triggers for these unmet needs, which can be roughly divided into two categories. One is the usual clinical characteristics for COPD patients, and the other is specific clinical characteristics in patients with comorbid conditions, such as asthma, cardiovascular disease, and bronchiectasis. These comorbidities, which are also associated with the diversity of COPD, can cause unmet needs resistance to usual care. However, treatable conditions that are not recognized as therapeutic targets may be latent in patients with COPD. We again realized that treatable traits should be assessed and treated as early as possible. In this article, we categorize potential therapeutic targets from the viewpoint of pulmonary and systemic comorbid conditions, and address recent data concerning the pathophysiological link with COPD and the impact of intervention on comorbid conditions in order to obtain evidence that could enable us to provide personalized COPD management.

A Proposed Approach to Chronic Airway Disease (CAD) Using Therapeutic Goals and Treatable Traits: A Look to the Future

Chronic airflow obstruction affects a wide range of airway diseases, the most frequent of which are asthma, COPD, and bronchiectasis; they are clearly identifiable in their extremes, but quite frequently overlap in some of their pathophysiological and clinical characteristics. This has generated the description of new mixed or overlapping disease phenotypes with no clear biological grounds. In this special article, a group of experts provides their perspective and proposes approaching the treatment of chronic airway disease (CAD) through the identification of a series of therapeutic goals (TG) linked to treatable traits (TT) - understood as clinical, physiological, or biological characteristics that are quantifiable using biomarkers. This therapeutic approach needs validating in a clinical trial with the strategy of identification of TG and treatment according to TT for each patient independently of their prior diagnosis.

Bugs, breathing and blood pressure: microbiota-gut-brain axis signalling in cardiorespiratory control in health and disease

There is clear evidence of physiological effects of the gut microbiota on whole-body function in health and disease. Microbiota-gut-brain axis signalling is recognised as a key player in behavioural disorders such as depression and anxiety. Recent evidence suggests that the gut microbiota affects neurocontrol networks responsible for homeostatic functions that are essential for life. We consider the evidence suggesting the potential for the gut microbiota to shape cardiorespiratory homeostasis. In various animal models of disease, there is an association between cardiorespiratory morbidity and perturbed gut microbiota, with strong evidence in support of a role of the gut microbiota in the control of blood pressure. Interventions that target the gut microbiota or manipulate the gut-brain axis, such as short-chain fatty acid supplementation, prevent hypertension in models of obstructive sleep apnoea. Emerging evidence points to a role for the microbiota-gut-brain axis in the control of breathing and ventilatory responsiveness, relevant to cardiorespiratory disease. There is also evidence for an association between the gut microbiota and disease severity in people with asthma and cystic fibrosis. There are many gaps in the knowledge base and an urgent need to better understand the mechanisms by which gut health and dysbiosis contribute to cardiorespiratory control. Nevertheless, there is a growing consensus that manipulation of the gut microbiota could prove an efficacious adjunctive strategy in the treatment of common cardiorespiratory diseases, which are the leading causes of morbidity and mortality.