Microbial Dysregulation of the Gut-Lung Axis in Bronchiectasis.

Rationale: Emerging data support the existence of a microbial "gut-lung" axis that remains unexplored in bronchiectasis. Methods: Prospective and concurrent sampling of gut (stool) and lung (sputum) was performed in a cohort of n = 57 individuals with bronchiectasis and subjected to bacteriome (16S rRNA) and mycobiome (18S Internal Transcribed Spacer) sequencing (total, 228 microbiomes). Shotgun metagenomics was performed in a subset (n = 15; 30 microbiomes). Data from gut and lung compartments were integrated by weighted similarity network fusion, clustered, and subjected to co-occurrence analysis to evaluate gut-lung networks. Murine experiments were undertaken to validate specific Pseudomonas-driven gut-lung interactions. Results: Microbial communities in stable bronchiectasis demonstrate a significant gut-lung interaction. Multibiome integration followed by unsupervised clustering reveals two patient clusters, differing by gut-lung interactions and with contrasting clinical phenotypes. A high gut-lung interaction cluster, characterized by lung Pseudomonas, gut Bacteroides, and gut Saccharomyces, is associated with increased exacerbations and greater radiological and overall bronchiectasis severity, whereas the low gut-lung interaction cluster demonstrates an overrepresentation of lung commensals, including Prevotella, Fusobacterium, and Porphyromonas with gut Candida. The lung Pseudomonas-gut Bacteroides relationship, observed in the high gut-lung interaction bronchiectasis cluster, was validated in a murine model of lung Pseudomonas aeruginosa infection. This interaction was abrogated after antibiotic (imipenem) pretreatment in mice confirming the relevance and therapeutic potential of targeting the gut microbiome to influence the gut-lung axis. Metagenomics in a subset of individuals with bronchiectasis corroborated our findings from targeted analyses. Conclusions: A dysregulated gut-lung axis, driven by lung Pseudomonas, associates with poorer clinical outcomes in bronchiectasis.

Heterogeneity of weight gain after initiation of Elexacaftor/Tezacaftor/Ivacaftor in people with cystic fibrosis.

BACKGROUND: The introduction of the novel therapy, Elexacaftor/Tezacaftor/Ivacaftor (ETI) has been effective in improving weight gain in both clinical trials and real-world studies. However, the magnitude of this effect appears to be heterogeneous across patient subgroups. This study aims to identify potential determinants of heterogeneity in weight gain following 6-month ETI therapy. METHODS: We conducted a multicenter, prospective cohort study enrolling 92 adults with CF at two major CF centers in Italy with follow-up visit at one month and six months from ETI initiation. The treatment's effect on weight changes was evaluated using mixed effect regression models that included subject-specific random intercepts and fixed effects for potential predictors of treatment response, time and a predictor-by-time interaction term. RESULTS: The mean weight gain at six months from the start of treatment was 4.6 kg (95% CI: 2.3-6.9) for the 10 patients with underweight, 3.2 kg (95% CI: 2.3-4.0) for the 72 patients with normal weight, and 0.7 kg (95% CI: -1.6-3.0) for the 10 patients with overweight. After six months of ETI treatment, 8 (80%) of the patients with underweight transitioned to the normal weight category, while 11 (15.3%) of the normal-weight patients became overweight. The major determinants of heterogeneity in weight gain were the baseline BMI and the presence of at least one CFTR residual function mutation, explaining 13% and 8% of the variability, respectively. CONCLUSIONS: Our results indicate that ETI is highly effective in improving weight gain in underweight subjects with CF. However, our data also suggests the need for close monitoring of excess weight gain to prevent potential cardiometabolic complications.

Walking the path of treatable traits in interstitial lung diseases.

Interstitial lung diseases (ILDs) are complex and heterogeneous diseases. The use of traditional diagnostic classification in ILD can lead to suboptimal management, which is worsened by not considering the molecular pathways, biological complexity, and disease phenotypes. The identification of specific "treatable traits" in ILDs, which are clinically relevant and modifiable disease characteristics, may improve patient's outcomes. Treatable traits in ILDs may be classified into four different domains (pulmonary, aetiological, comorbidities, and lifestyle), which will facilitate identification of related assessment tools, treatment options, and expected benefits. A multidisciplinary care team model is a potential way to implement a "treatable traits" strategy into clinical practice with the aim of improving patients' outcomes. Multidisciplinary models of care, international registries, and the use of artificial intelligence may facilitate the implementation of the "treatable traits" approach into clinical practice. Prospective studies are needed to test potential therapies for a variety of treatable traits to further advance care of patients with ILD.

Treatable traits and challenges in the clinical management of non-tuberculous mycobacteria lung disease in people with cystic fibrosis.

INTRODUCTION: Over the last ten years an increasing prevalence and incidence of non-tuberculous mycobacteria (NTM) has been reported among patients with cystic fibrosis (CF) Viviani (J Cyst Fibros, 15(5):619-623, 2016). NTM pulmonary disease has been associated with negative clinical outcomes and often requires pharmacological treatment. Although specific guidelines help clinicians in the process of diagnosis and clinical management, the focus on the multidimensional assessment of concomitant problems is still scarce. MAIN BODY: This review aims to identify the treatable traits of NTM pulmonary disease in people with CF and discuss the importance of a multidisciplinary approach in order to detect and manage all the clinical and behavioral aspects of the disease. The multidisciplinary complexity of NTM pulmonary disease in CF requires careful management of respiratory and extra-respiratory, including control of comorbidities, drug interactions and behavioral factors as adherence to therapies. CONCLUSIONS: The treatable trait strategy can help to optimize clinical management through systematic assessment of all the aspects of the disease, providing a holistic treatment for such a multi-systemic and complex condition.

Non-tuberculous mycobacteria lung disease due to Mycobacterium chimaera in a 67-year-old man treated with immune checkpoint inhibitors for lung adenocarcinoma: infection due to dysregulated immunity?

Immune checkpoint inhibitors (ICIs) are drugs growingly employed in cancer immunotherapy which have significantly improved the prognosis of several tumours. ICIs act by restoring the "exhausted" immune system and increasing the number of T cells active against pathogens losing tolerogenic signalling, which has been linked to an increased risk of infectious events. We present the case of a 67-year-old man with locally advanced lung adenocarcinoma treated with the anti-PD-L1 durvalumab. Three months after immunotherapy started, an apparent radiological progression was found with elements suggesting a parenchymal superinfection associated with weight loss, asthenia, and sputum emission. A bronchoalveolar lavage resulted positive for Mycobacterium chimaera, and treatment with amikacin iv (for eight weeks) and daily azithromycin, ethambutol, and rifampicin was started. Thirteen months after treatment started, the patient is alive with a stable lung condition. The case highlights the risk of non-tuberculous mycobacteria lung disease (NTM-LD) in patients receiving ICIs treatment. We hypothesise that durvalumab induced an exaggerated immune response toward the mycobacteria, leading to immunopathology and overt clinical manifestations. Clinicians should be aware of this possibility in patients receiving ICIs developing new signs/symptoms related to the respiratory tract, especially in countries with a high prevalence of NTM-LD.

Unplanned pregnancies following the introduction of elexacaftor/tezacaftor/ivacaftor therapy in women with cystic fibrosis.

Cystic fibrosis (CF) causes infertility and subfertility due to various factors, including altered cervical mucus, delayed puberty, and hormonal imbalances. With the introduction of the CFTR modulator therapy elexacaftor-tezacaftor-ivacaftor, we have observed an increase in unplanned pregnancies among women undergoing ETI treatment in our CF center, despite repeated recommendations for strict fertility monitoring. It appears that these pregnancies are more likely attributed to reduced attention to the possibility of conception rather than contraceptive failure. The perception of subfertility developed by women with CF over time, before the era of modulators, can influence their long-term habits and lead to the underuse of contraceptive methods. While further research is needed to fully understand the effects of ETI on fertility, healthcare providers should be attentive to the fertility concerns of women with CF, particularly those treated with modulators in adulthood.

Efficacy of Pirfenidone and Nintedanib in Interstitial Lung Diseases Other than Idiopathic Pulmonary Fibrosis: A Systematic Review.

Pirfenidone and nintedanib are antifibrotic medications approved for idiopathic pulmonary fibrosis treatment by regulatory agencies and available for clinical use worldwide. These drugs have been shown to reduce the rate of decline in forced vital capacity and the risk of acute exacerbation among patients with idiopathic pulmonary fibrosis. Recent data suggest that different interstitial lung diseases with a progressive pulmonary fibrosis phenotype can share similar pathogenetic and biological pathways and could be amenable to antifibrotic therapies. Indeed, historical management strategies in interstitial lung disease have failed to identify potential treatments once progression has occurred despite available drugs. In this systematic review, we summarized data on the efficacy of pirfenidone and nintedanib in interstitial lung diseases other than idiopathic pulmonary fibrosis as well as ongoing and upcoming clinical trials. We identify two well-designed trials regarding nintedanib demonstrating the efficacy of this drug in slowing disease progression in patients with interstitial lung diseases other than idiopathic pulmonary fibrosis. On the other hand, results on the use of pirfenidone in interstitial lung diseases other than idiopathic pulmonary fibrosis should be interpreted with more caution on the basis of trial limitations. Several randomized control trials are underway to improve the quality of evidence in the interstitial lung disease field.

Pro-resolving and pro-inflammatory fatty acid-derived mediators in sputum of stable state bronchiectasis patients.

BACKGROUND: Bronchiectasis is characterized by neutrophilic inflammation and frequent exacerbations often associated with infections. Lipid mediators play critical roles in the inflammatory response, and the balance between anti-inflammatory and pro-inflammatory mediators could drive to chronic inflammation. The aim of this study was to evaluate the metabolites of docosahexaenoic acid and arachidonic acid in sputum of adults with bronchiectasis defining their associations with clinical data, bacterial load and neutrophil elastase. METHODS: An observational, cross-sectional study was conducted at the bronchiectasis program of the Policlinico Hospital in Milan, Italy, where patients were enrolled. Active neutrophil elastase was measured by enzyme-linked immunosorbent assay, pro-resolving and pro-inflammatory fatty acid-derived mediators were evaluated by mass spectrometry and respiratory pathogens were assessed by real-time PCR. Analysis were performed on sputum collected during stable state and clinical data were also collected. RESULTS: Levels of pro-inflammatory mediators derived from arachidonic acid metabolism showed association with neutrophil elastase, were proportional to Pseudomonas aeruginosa identifications and were linked with radiological gravity index, while the concentrations of pro-resolution mediators derived from docosahexaenoic acid were associated with a better health status, highlighted by the inverse correlation with radiological gravity index, bacterial infections and sputum volume production. CONCLUSION: Pro-inflammatory mediators derived from FA metabolisms are associated with severity of bronchiectasis while DHA-derived metabolites are inversely associated with severity of the disease, which may be used for personized treatment of bronchiectasis.

Lung Microbiome in Idiopathic Pulmonary Fibrosis and Other Interstitial Lung Diseases.

Interstitial lung diseases represent a heterogeneous and wide group of diseases in which factors leading to disease initiation and progression are not fully understood. Recent evidence suggests that the lung microbiome might influence the pathogenesis and progression of interstitial lung diseases. In recent years, the utilization of culture-independent methodologies has allowed the identification of complex and dynamic communities of microbes, in patients with interstitial lung diseases. However, the potential mechanisms by which these changes may drive disease pathogenesis and progression are largely unknown. The aim of this review is to discuss the role of the altered lung microbiome in several interstitial lung diseases. Untangling the host-microbiome interaction in the lung and airway of interstitial lung disease patients is a research priority. Thus, lung dysbiosis is a potentially treatable trait across several interstitial lung diseases, and its proper characterization and treatment might be crucial to change the natural history of these diseases and improve outcomes.

Prevalence and serotyping of S. pneumoniae in a large vaccine-naive cohort of adults with cystic fibrosis.

We conducted a prospective, observational study at the Adult CF Center, Ospedale Policlinico, Milano, Italy, from March 2017 to September 2019 to assess the prevalence and serotypes of Streptococcus pneumoniae (SP) in adults with CF naive to pneumococcal vaccination. Spontaneous sputum samples from 129 patients were analyzed for SP DNA and serotyped. SP was found in 24 subjects (19%) and the most common serotypes were 19F (16%), 4 (6%), and 9VA (3%). Higher FEV1 and non-pseudomonas infection significantly associate with SP on sputum. These results define a subgroup of patients that might deserve implementation of microbiological techniques directed to pneumococcal detection.

COVID-19 in Immunocompromised Patients: A Systematic Review.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) was first identified as a novel coronavirus in Wuhan, Hubei province, central China, in December 2019, and is responsible for the 2019-to-present pandemic. According to the most recent data released by the World Health Organization, more than 200 million people have been infected by SARS-CoV-2 so far, and more than 4 million people died worldwide. Although our knowledge on SARS-CoV-2 and COVID-19 is constantly growing, data on COVID-19 in immunocompromised patients are still limited. The aim of the present systematic review is to describe clinical picture, disease severity, proposed treatment regimen, and response to vaccination in patients with different types and severity of immunosuppression.

Diagnosis and Initial Investigation of Bronchiectasis.

Bronchiectasis refers to both the name of a disease and a single radiological appearance that may, or may not, be associated with disease. As chronic respiratory disease, bronchiectasis is characterized by a variable range of signs and symptoms that may overlap with other chronic respiratory conditions. The proper identification of bronchiectasis as a disease in both primary and secondary care is of paramount importance. However, a standardized definition of radiologically and clinically significant bronchiectasis is still missing. Disease heterogeneity is a hallmark of bronchiectasis and applies not only to radiological features and clinical manifestations but also to other aspects of the disease, including the etiological and microbiological diagnosis as well as the evaluation of pulmonary function. Although the guidelines suggest a "minimum bundle" of tests, the diagnostic approach to bronchiectasis is challenging and may be driven by the "treatable traits" approach based on endotypes and biological characteristics. A broad spectrum of diagnostic tests could be used to investigate the etiology of bronchiectasis as well as other pulmonary, extrapulmonary, and environmental traits. Individualizing bronchiectasis workup according to the site of care (e.g., primary, secondary, and tertiary care) could help optimize patients' management and reduce healthcare costs.

Protease-Antiprotease Imbalance in Bronchiectasis.

Airway inflammation plays a central role in bronchiectasis. Protease-antiprotease balance is crucial in bronchiectasis pathophysiology and increased presence of unopposed proteases activity may contribute to bronchiectasis onset and progression. Proteases' over-reactivity and antiprotease deficiency may have a role in increasing inflammation in bronchiectasis airways and may lead to extracellular matrix degradation and tissue damage. Imbalances in serine proteases and matrix-metallo proteinases (MMPs) have been associated to bronchiectasis. Active neutrophil elastase has been associated with disease severity and poor long-term outcomes in this disease. Moreover, high levels of MMPs have been associated with radiological and disease severity. Finally, severe deficiency of α1-antitrypsin (AAT), as PiSZ and PiZZ (proteinase inhibitor SZ and ZZ) phenotype, have been associated with bronchiectasis development. Several treatments are under study to reduce protease activity in lungs. Molecules to inhibit neutrophil elastase activity have been developed in both oral or inhaled form, along with compounds inhibiting dipeptydil-peptidase 1, enzyme responsible for the activation of serine proteases. Finally, supplementation with AAT is in use for patients with severe deficiency. The identification of different targets of therapy within the protease-antiprotease balance contributes to a precision medicine approach in bronchiectasis and eventually interrupts and disrupts the vicious vortex which characterizes the disease.

Sputum neutrophil elastase associates with microbiota and Pseudomonas aeruginosa in bronchiectasis.

INTRODUCTION: Neutrophilic inflammation is a major driver of bronchiectasis pathophysiology, and neutrophil elastase activity is the most promising biomarker evaluated in sputum to date. How active neutrophil elastase correlates with the lung microbiome in bronchiectasis is still unexplored. We aimed to understand whether active neutrophil elastase is associated with low microbial diversity and distinct microbiome characteristics. METHODS: An observational, cross-sectional study was conducted at the bronchiectasis programme of the Policlinico Hospital in Milan, Italy, where adults with bronchiectasis were enrolled between March 2017 and March 2019. Active neutrophil elastase was measured on sputum collected during stable state, microbiota analysed through 16S rRNA gene sequencing, molecular assessment of respiratory pathogens carried out through real-time PCR and clinical data collected. RESULTS: Among 185 patients enrolled, decreasing α-diversity, evaluated through the Shannon entropy (ρ -0.37, p<0.00001) and Pielou's evenness (ρ -0.36, p<0.00001) and richness (ρ -0.33, p<0.00001), was significantly correlated with increasing elastase. A significant difference in median levels of Shannon entropy as detected between patients with neutrophil elastase ≥20 µg·mL-1 (median 3.82, interquartile range 2.20-4.96) versus neutrophil elastase <20 µg·mL-1 (4.88, 3.68-5.80; p<0.0001). A distinct microbiome was found in these two groups, mainly characterised by enrichment with Pseudomonas in the high-elastase group and with Streptococcus in the low-elastase group. Further confirmation of the association of Pseudomonas aeruginosa with elevated active neutrophil elastase was found based on standard culture and targeted real-time PCR. CONCLUSIONS: High levels of active neutrophil elastase are associated to low microbiome diversity and specifically to P. aeruginosa infection.

COVID-19 multidisciplinary high dependency unit: the Milan model.

COVID-19 is a complex and heterogeneous disease. The pathogenesis and the complications of the disease are not fully elucidated, and increasing evidence shows that SARS-CoV-2 causes a systemic inflammatory disease rather than a pulmonary disease. The management of hospitalized patients in COVID-19 dedicated units is advisable for segregation purpose as well as for infection control. In this article we present the standard operating procedures of our COVID-19 high dependency unit of the Policlinico Hospital, in Milan. Our high dependency unit is based on a multidisciplinary approach. We think that the multidisciplinary involvement of several figures can better identify treatable traits of COVID-19 disease, early identify patients who can quickly deteriorate, particularly patients with multiple comorbidities, and better manage complications related to off-label treatments. Although no generalizable to other hospitals and different healthcare settings, we think that our experience and our point of view can be helpful for countries and hospitals that are now starting to face the COVID-19 outbreak.

Correction to: Atypical pathogens in hospitalized patients with community-acquired pneumonia: a worldwide perspective.

An amendment to this paper has been published and can be accessed via the original article.

Prevalence and incidence of bronchiectasis in Italy.

BACKGROUND: The understanding of the epidemiology of bronchiectasis is still affected by major limitations with very few data published worldwide. The aim of this study was to estimate the epidemiological burden of bronchiectasis in Italy in the adult population followed-up by primary care physicians. METHODS: This study analyzed data coming from a large primary care database with 1,054,376 subjects in the period of time 2002-2015. Patients with bronchiectasis were selected by the use of International Statistical Classification of Diseases, 9th revision, Clinical Modification codes (ICD-9-CM). RESULTS: Patients with bronchiectasis were more likely to have a history of tuberculosis (0.47% vs. 0.06%, p < 0.0001), had higher rates of asthma (16.6% vs. 6.2%, p < 0.0001), COPD (23.3% vs. 6.4%, p < 0.0001) and rheumatoid arthritis (1.9% vs. 0.8%, p < 0.0001). The prevalence and incidence of bronchiectasis in primary care in Italy in 2015 were 163 per 100,000 population and 16.3 per 100,000 person-years, respectively. Prevalence and incidence increased with age and overall rates were highest in men over 75 years old. Prevalence and incidence computed after the exclusion of patients with a diagnosis of either asthma or COPD is 130 per 100,000 and 11.1 cases per 100,000 person-years, respectively. CONCLUSIONS: Bronchiectasis is not a rare condition in Italian adult population. Further studies are needed to confirm our results and provide a better insight on etiology of bronchiectasis in Italy. TRIAL REGISTRATION: not applicable.

From Ivacaftor to Triple Combination: A Systematic Review of Efficacy and Safety of CFTR Modulators in People with Cystic Fibrosis.

Over the last years CFTR (cystic fibrosis transmembrane conductance regulator) modulators have shown the ability to improve relevant clinical outcomes in patients with cystic fibrosis (CF). This review aims at a systematic research of the current evidence on efficacy and tolerability of CFTR modulators for different genetic subsets of patients with CF. Two investigators independently performed the search on PubMed and included phase 2 and 3 clinical trials published in the study period 1 January 2005-31 January 2020. A final pool of 23 papers was included in the systematic review for a total of 4219 patients. For each paper data of interest were extracted and reported in table. In terms of lung function, patients who had the most beneficial effects from CFTR modulation were those patients with one gating mutation receiving IVA (ivacaftor) and patients with p.Phe508del mutation, both homozygous and heterozygous, receiving ELX/TEZ/IVA (elexacaftor/tezacaftor/ivacaftor) had the most relevant beneficial effects in term of lung function, pulmonary exacerbation decrease, and symptom improvement. CFTR modulators showed an overall favorable safety profile. Next steps should aim to systematize our comprehension of scientific data of efficacy and safety coming from real life observational studies.

Prevalence and Etiology of Community-acquired Pneumonia in Immunocompromised Patients.

BACKGROUND: The correct management of immunocompromised patients with pneumonia is debated. We evaluated the prevalence, risk factors, and characteristics of immunocompromised patients coming from the community with pneumonia. METHODS: We conducted a secondary analysis of an international, multicenter study enrolling adult patients coming from the community with pneumonia and hospitalized in 222 hospitals in 54 countries worldwide. Risk factors for immunocompromise included AIDS, aplastic anemia, asplenia, hematological cancer, chemotherapy, neutropenia, biological drug use, lung transplantation, chronic steroid use, and solid tumor. RESULTS: At least 1 risk factor for immunocompromise was recorded in 18% of the 3702 patients enrolled. The prevalences of risk factors significantly differed across continents and countries, with chronic steroid use (45%), hematological cancer (25%), and chemotherapy (22%) the most common. Among immunocompromised patients, community-acquired pneumonia (CAP) pathogens were the most frequently identified, and prevalences did not differ from those in immunocompetent patients. Risk factors for immunocompromise were independently associated with neither Pseudomonas aeruginosa nor non-community-acquired bacteria. Specific risk factors were independently associated with fungal infections (odds ratio for AIDS and hematological cancer, 15.10 and 4.65, respectively; both P = .001), mycobacterial infections (AIDS; P = .006), and viral infections other than influenza (hematological cancer, 5.49; P < .001). CONCLUSIONS: Our findings could be considered by clinicians in prescribing empiric antibiotic therapy for CAP in immunocompromised patients. Patients with AIDS and hematological cancer admitted with CAP may have higher prevalences of fungi, mycobacteria, and noninfluenza viruses.