A Bacterial Quorum Sensing Regulated Protease Inhibits Host Immune Responses by Cleaving Death Domains of Innate Immune Adaptors.

Innate immune adaptor proteins are critical components of the innate immune system that propagate pro-inflammatory responses from their upstream receptors, and lead to pathogen clearance from the host. Bacterial pathogens have developed strategies to survive inside host cells without triggering the innate immune surveillance in ways that are still not fully understood. Here, it is reported that Pseudomonas aeruginosa induces its quorum sensing mechanism after macrophage engulfment. Further investigation of its secretome identified a quorum sensing regulated product, LasB, is responsible for innate immune suppression depending on the MyD88-mediated signaling. Moreover, it is showed that this specific type of pathogen-mediated innate immune suppression is due to the enzymatic digestion of the death domains of the innate immune adaptors, mainly MyD88, and attributed to LasB's large substrate binding groove. Lastly, it is demonstrated that the secretion of LasB from P. aeruginosa directly contributed to MyD88 degradation within macrophages. Hence, it is discovered an example of bacterial quorum sensing-regulated cellular innate immune suppression by direct cleavage of immune adaptors.

Bronchiectasis and cough: An old relationship in need of renewed attention.

Bronchiectasis is an increasingly recognised respiratory condition with limited therapeutic options and a complex spectrum of clinical manifestations that invariably includes chronic cough. As the primary presentation of bronchiectasis in most cases, chronic cough and its mechanistic underpinnings are of central importance but remain poorly understood in this setting. Bronchiectasis is also increasingly identified as an underlying cause of chronic cough highlighting the interrelationship between the two conditions that share overlapping clinical features. Several therapeutic approaches have illustrated positive effects on bronchiectasis-associated cough, however, more focused treatment of heterogeneous cough subtypes may yield better outcomes for patients. A current challenge is the identification of bronchiectasis and cough endophenotypes that may allow improved patient stratification and more targeted therapeutic matching of the right treatment to the right patient. Here we discuss the complex disease phenotypes of bronchiectasis and their interrelationship with cough while considering current and emerging treatment options. We discuss some key cough promoters in bronchiectasis including infection, allergy and immune dysfunction.

Inhaled nanomaterials and the respiratory microbiome: clinical, immunological and toxicological perspectives.

Our development and usage of engineered nanomaterials has grown exponentially despite concerns about their unfavourable cardiorespiratory consequence, one that parallels ambient ultrafine particle exposure from vehicle emissions. Most research in the field has so far focused on airway inflammation in response to nanoparticle inhalation, however, little is known about nanoparticle-microbiome interaction in the human airway and the environment. Emerging evidence illustrates that the airway, even in its healthy state, is not sterile. The resident human airway microbiome is further altered in chronic inflammatory respiratory disease however little is known about the impact of nanoparticle inhalation on this airway microbiome. The composition of the airway microbiome, which is involved in the development and progression of respiratory disease is dynamic, adding further complexity to understanding microbiota-host interaction in the lung, particularly in the context of nanoparticle exposure. This article reviews the size-dependent properties of nanomaterials, their body deposition after inhalation and factors that influence their fate. We evaluate what is currently known about nanoparticle-microbiome interactions in the human airway and summarise the known clinical, immunological and toxicological consequences of this relationship. While associations between inhaled ambient ultrafine particles and host immune-inflammatory response are known, the airway and environmental microbiomes likely act as intermediaries and facilitate individual susceptibility to inhaled nanoparticles and toxicants. Characterising the precise interaction between the environment and airway microbiomes, inhaled nanoparticles and the host immune system is therefore critical and will provide insight into mechanisms promoting nanoparticle induced airway damage.

Understanding COPD-overlap syndromes.

INTRODUCTION: Chronic obstructive pulmonary disease accounts for a large burden of lung disease. It can 'overlap' with other respiratory diseases including bronchiectasis, fibrosis and obstructive sleep apnea (OSA). While COPD alone confers morbidity and mortality, common features with contrasting clinical outcomes can occur in COPD 'overlap syndromes'. Areas covered: Given the large degree of heterogeneity in COPD, individual variation to treatment is adopted based on its observed phenotype, which in turn overlaps with features of other respiratory disease states such as asthma. This is coined asthma-COPD overlap syndrome ('ACOS'). Other examples of such overlapping clinical states include bronchiectasis-COPD ('BCOS'), fibrosis-COPD ('FCOS') and OSA-COPD ('OCOS'). The objective of this review is to highlight similarities and differences between the COPD-overlap syndromes in terms of risk factors, pathophysiology, diagnosis and potential treatment differences. Expert commentary: As a consequence of COPD overlap syndromes, a transition from the traditional 'one size fits all' treatment approach is necessary. Greater treatment stratification according to clinical phenotype using a precision medicine approach is now required. In this light, it is important to recognize and differentiate COPD overlap syndromes as distinct disease states compared to individual diseases such as asthma, COPD, fibrosis or bronchiectasis.

Radiological abnormalities associated with Aspergillus colonization in a cystic fibrosis population.

OBJECTIVE: To determine if sputum colonization with Aspergillus species in patients with cystic fibrosis (PWCF) correlates with radiological abnormalities and/or a reduction in pulmonary function (FEV1). METHODS: We prospectively evaluated 32 PWCF utilizing high resolution computed tomography (HRCT) of the thorax and pulmonary function testing (PFT). The cohort was assessed as two groups: Aspergillus positive (n=16) and Aspergillus negative (n=16) based on sputum culture for Aspergillus species. A modified Bhalla scoring system was applied to each HRCT scan by two blinded radiologists. RESULTS: Aspergillus positive patients had more severe and significant bronchiectasis compared to those Aspergillus negative (p<0.05). This was most marked in the right upper and lower lobes (RUL, RLL). Total Bhalla score was clinically significant in both groups and approached statistical significance between groups (p=0.063). No difference in pulmonary function between the groups was detected. CONCLUSION: PWCF colonized by Aspergillus species have greater radiological abnormalities undetectable by PFTs. Early radiological evaluation of Aspergillus colonized PWCF is therefore warranted.

Extubation versus tracheostomy in withdrawal of treatment-ethical, clinical, and legal perspectives.

The provision of life-sustaining ventilation, such as tracheostomy to critically ill patients, is commonly performed. However, the utilization of tracheostomy or extubation after a withdrawal of treatment decision is debated. There is a dearth of practical information available to aid clinical decision making because withdrawal of treatment is a challenging scenario for all concerned. This is further complicated by medicolegal and ethical considerations. Care of the "hopelessly ill" patient should be based on daily evaluation and comfort making it impossible to fit into general algorithms. Although respect for autonomy is important in healthcare, it is limited for patients in an unconscious state. Beneficence remains the basis for withdrawing treatment in futile cases and underpins the "doctrine of double effect." This article presents a relevant clinical case of hypoxic brain injury where a question of withdrawal of treatment arose and examines the ethical, clinical, and medicolegal considerations inherent in such cases, including beneficence, nonmaleficence, and the "sanctity of life doctrine." In addition, the considerations of prognosis for recovery, patient autonomy, patient quality of life, and patient family involvement, which are central to decision making, are addressed. The varying legal frameworks that exist internationally regarding treatment withdrawal are also described. Good ethics needs sound facts, and despite the lack of legal foundation in several countries, withdrawal of treatment remains practiced, and the principles described within this article aim to aid clinician decision making during such complex and multifaceted end-of-life decisions.

Diagnosis and management of asthma in older adults.

Despite comprehensive guidelines established by the European Global Initiative for Asthma and the U.S. National Asthma Education and Prevention Program on the diagnosis and management of asthma, its mortality in older adults continues to rise. Diagnostic and therapeutic problems contribute to older patients being inadequately treated. The diagnosis of asthma rests on the history and characteristic pulmonary function testing (PFT) with the demonstration of reversible airway obstruction, but there are unique problems in performing this test in older patients and in its interpretation. This review aims to address the difficulties in performing and interpreting PFT in older patients because of the effects of age-related changes in lung function on respiratory physiology. The concept of "airway remodeling" resulting in "fixed obstructive" PFT and the relevance of atopy in older people with asthma are assessed. There are certain therapeutic issues unique to older patients with asthma, including the increased probability of adverse effects in the setting of multiple comorbidities and issues surrounding effective drug delivery. The use of beta 2-agonist, anticholinergic, corticosteroid, and anti-immunoglobulin E treatments are discussed in the context of these therapeutic issues.

Aspergillus/allergic bronchopulmonary aspergillosis in an Irish cystic fibrosis population: a diagnostically challenging entity.

BACKGROUND: Patients with cystic fibrosis (CF) can become colonized by aspergillus, which can act as an allergen and cause allergic bronchopulmonary aspergillosis (ABPA). OBJECTIVE: To determine the rate of aspergillus colonization and ABPA in a population of Irish patients with CF. METHODS: In 50 consecutive patients with CF who presented with exacerbations, we looked for the presence of aspergillus in their sputum and signs and symptoms of ABPA. RESULTS: Fifteen patients (30%) grew aspergillus species in their sputum cultures. Six patients (12%) had ABPA. Matched for age, sex, genotype, and microbiology, there was no significant difference in forced expiratory volume in the first second (percent predicted, FEV(1)%) in subjects with aspergillus-positive sputum compared to those not colonized with aspergillus. Subjects with ABPA experienced sharp short-term deterioration in lung function (mean 6.7% predicted FEV(1)), which returned to baseline following at least 4 weeks of treatment. CONCLUSIONS: The prevalence of ABPA was 12%. Aspergillus-positive sputum of itself was not a poor prognostic sign in terms of lung function over the 5-year study course. ABPA produces short-term reversible declines in lung function and responds to treatment. The frequency of aspergillus isolates did not correlate with the occurrence of ABPA. A low threshold for the diagnosis of ABPA should be maintained in any patient with CF who does not improve with antibiotics.