Dornase alfa for cystic fibrosis

Association between extracellular DNA levels, markers of inflammation and left ventricular mass index in children with chronic kidney disease

Chronic kidney disease (CKD) is associated with chronic low-grade inflammation, but the primary factors triggering this inflammation remain unclear. Extracellular or cell-free DNA (exDNA) originates from virtually all tissues, being released during cell death, and stimulates the innate immune system. Our study was designed as an observational, cross-sectional cohort study of children with CKD (both before and after kidney transplantation) and controls to analyze associations between exDNA, markers of inflammation, and cardiovascular health. Extracellular DNA (total, nuclear, and mitochondrial) was analyzed in plasma using fluorometry and real-time PCR. We found that children with CKD after kidney transplantation had higher concentrations of total and nuclear extracellular DNA (total exDNA and nc_exDNA) in plasma compared to controls. In univariate analysis, levels of interleukin-6 (IL-6), antimicrobial peptide cathelicidin (LL-37), soluble vascular cell adhesion molecule-1 (VCAM-1) and left ventricular mass index (LVMI) were positively correlated with total exDNA and nc_exDNA concentrations. Multivariate analysis revealed LVMI as the only independent variable associated with high levels of both total exDNA and nc_exDNA. We believe that our results contribute new knowledge to the pathogenesis of CKD and its complications and may help identify new treatment targets.

Neutrophil diversity and function in health and disease

Neutrophils, the most abundant type of granulocyte, are widely recognized as one of the pivotal contributors to the acute inflammatory response. Initially, neutrophils were considered the mobile infantry of the innate immune system, tasked with the immediate response to invading pathogens. However, recent studies have demonstrated that neutrophils are versatile cells, capable of regulating various biological processes and impacting both human health and disease. Cytokines and other active mediators regulate the functional activity of neutrophils by activating multiple receptors on these cells, thereby initiating downstream signal transduction pathways. Dysfunctions in neutrophils and disruptions in neutrophil homeostasis have been implicated in the pathogenesis of numerous diseases, including cancer and inflammatory disorders, often due to aberrant intracellular signaling. This review provides a comprehensive synthesis of neutrophil biological functions, integrating recent advancements in this field. Moreover, it examines the biological roles of receptors on neutrophils and downstream signaling pathways involved in the regulation of neutrophil activity. The pathophysiology of neutrophils in numerous human diseases and emerging therapeutic approaches targeting them are also elaborated. This review also addresses the current limitations within the field of neutrophil research, highlighting critical gaps in knowledge that warrant further investigation. In summary, this review seeks to establish a comprehensive and multidimensional model of neutrophil regulation, providing new perspectives for potential clinical applications and further research.

What Is a Biofilm? Lessons Learned from Interactions with Immune Cells

Biofilms are unique, multicellular life forms that challenge our understanding of the microbial functioning. The last decades of research on biofilms have allowed us to better understand their importance in the context of both health and various pathologies in the human body, although many knowledge gaps hindering their correct comprehension still exist. Biofilms are classically described as mushroom-shaped structures attached to the substrate; however, an increasing body of evidence shows that their morphology in clinical conditions may differ significantly from that classically presented. Although this may result partly from the unique physicochemical conditions within the host, the interaction between microbes and immune cells during development of a biofilm should not be underestimated. The current Opinion confronts the classical view on biofilms with the latest scientific research describing the vitality of interactions with immune cells as a modulator of the biofilm phenotype and behavior in clinical conditions.

Dysregulated neutrophil extracellular traps and haemostatic biomarkers as diagnostic tools and therapeutic targets in periprosthetic joint infection

Aims

Bacterial infection activates neutrophils to release neutrophil extracellular traps (NETs) in bacterial biofilms of periprosthetic joint infections (PJIs). The aim of this study was to evaluate the increase in NET activation and release (NETosis) and haemostasis markers in the plasma of patients with PJI, to evaluate whether such plasma induces the activation of neutrophils, to ascertain whether increased NETosis is also mediated by reduced DNaseI activity, to explore novel therapeutic interventions for NETosis in PJI in vitro, and to evaluate the potential diagnostic use of these markers.

Methods

We prospectively recruited 107 patients in the preoperative period of prosthetic surgery, 71 with a suspicion of PJI and 36 who underwent arthroplasty for non-septic indications as controls, and obtained citrated plasma. PJI was confirmed in 50 patients. We measured NET markers, inflammation markers, DNaseI activity, haemostatic markers, and the thrombin generation test (TGT). We analyzed the ability of plasma from confirmed PJI and controls to induce NETosis and to degrade in vitro-generated NETs, and explored the therapeutic restoration of the impairment to degrade NETs of PJI plasma with recombinant human DNaseI. Finally, we assessed the contribution of these markers to the diagnosis of PJI.

Results

Patients with confirmed PJI had significantly increased levels of NET markers (cfDNA (p < 0.001), calprotectin (p < 0.001), and neutrophil elastase (p = 0.022)) and inflammation markers (IL-6; p < 0.001) in plasma. Moreover, the plasma of patients with PJI induced significantly more neutrophil activation than the plasma of the controls (p < 0.001) independently of tumour necrosis factor alpha. Patients with PJI also had a reduced DNaseI activity in plasma (p < 0.001), leading to a significantly impaired degradation of NETs (p < 0.001). This could be therapeutically restored with recombinant human DNaseI to the level in the controls. We developed a model to improve the diagnosis of PJI with cfDNA, calprotectin, and the start tail of TGT as predictors, though cfDNA alone achieved a good prediction and is simpler to measure.

Conclusion

We confirmed that patients with PJI have an increased level of NETosis in plasma. Their plasma both induced NET release and had an impaired ability to degrade NETs mediated by a reduced DNaseI activity. This can be therapeutically restored in vitro with the approved Dornase alfa, Pulmozyme, which may allow novel methods of treatment. A combination of NETs and haemostatic biomarkers could improve the diagnosis of PJI, especially those patients in whom this diagnosis is uncertain.

DNA-sensing inflammasomes cause recurrent atherosclerotic stroke

The risk of early recurrent events after stroke remains high despite currently established secondary prevention strategies1. Risk is particularly high in patients with atherosclerosis, with more than 10% of patients experiencing early recurrent events1,2. However, despite the enormous medical burden of this clinical phenomenon, the underlying mechanisms leading to increased vascular risk and recurrent stroke are largely unknown. Here, using a novel mouse model of stroke-induced recurrent ischaemia, we show that stroke leads to activation of the AIM2 inflammasome in vulnerable atherosclerotic plaques via an increase of circulating cell-free DNA. Enhanced plaque inflammation post-stroke results in plaque destabilization and atherothrombosis, finally leading to arterioarterial embolism and recurrent stroke within days after the index stroke. We confirm key steps of plaque destabilization also after experimental myocardial infarction and in carotid artery plaque samples from patients with acute stroke. Rapid neutrophil NETosis was identified as the main source of cell-free DNA after stroke and NET-DNA as the causative agent leading to AIM2 inflammasome activation. Neutralization of cell-free DNA by DNase treatment or inhibition of inflammasome activation reduced the rate of stroke recurrence after experimental stroke. Our findings present an explanation for the high recurrence rate after incident ischaemic events in patients with atherosclerosis. The detailed mechanisms uncovered here provide clinically uncharted therapeutic targets for which we show high efficacy to prevent recurrent events. Targeting DNA-mediated inflammasome activation after remote tissue injury represents a promising avenue for further clinical development in the prevention of early recurrent events.

The continuing need for dornase alfa for extracellular airway DNA hydrolysis in the era of CFTR modulators

INTRODUCTION

The availability of cystic fibrosis transmembrane conductance regulator (CFTR) modulators opens the possibility of discontinuing some chronic pulmonary therapies to decrease cystic fibrosis (CF) treatment burden. However, CFTR modulators may not adequately address neutrophilic inflammation, which contributes to a self-perpetual cycle of viscous CF sputum, airway obstruction, inflammation, and lung function decline.

AREAS COVERED

This review discusses the emerging role of neutrophil extracellular traps in CF and its role in CF sputum viscosity, airway obstruction, and inflammation, based on a literature search of PubMed (1990-present). We summarize clinical trials and real-world studies that support the efficacy of dornase alfa (Pulmozyme) in improving lung function and reducing pulmonary exacerbation in people with CF (PwCF), and we discuss the potential role of dornase alfa in reducing airway inflammation. We also examine the findings of short-term trials evaluating the discontinuation of mucoactive therapy in PwCF receiving CFTR modulators.

EXPERT OPINION

Long-term studies are needed to assess the impact of discontinuing mucoactive therapy in PwCF who are clinically stable while receiving CFTR modulatory therapy. Treatment decisions should take into account the severity of underlying lung disease. People with advanced CF will likely require ongoing mucoactive therapy.

Systemic mechanisms of necrotic cell debris clearance

Necrosis is an overarching term that describes cell death modalities caused by (extreme) adverse conditions in which cells lose structural integrity. A guaranteed consequence of necrosis is the production of necrotic cell remnants, or debris. Necrotic cell debris is a strong trigger of inflammation, and although inflammatory responses are required for tissue healing, necrotic debris may lead to uncontrolled immune responses and collateral damage. Besides local phagocytosis by recruited leukocytes, there is accumulating evidence that extracellular mechanisms are also involved in necrotic debris clearance. In this review, we focused on systemic clearance mechanisms present in the bloodstream and vasculature that often cooperate to drive the clearance of cell debris. We reviewed the contribution and cooperation of extracellular DNases, the actin-scavenger system, the fibrinolytic system and reticuloendothelial cells in performing clearance of necrotic debris. Moreover, associations of the (mis)functioning of these clearance systems with a variety of diseases were provided, illustrating the importance of the mechanisms of clearance of dead cells in the organism.

[Primary ciliary dyskinesia]

Primary ciliary dyskinesia (PCD) is a rare genetic disorder with a variable clinical phenotype that is accompanied by reduced motility of the cilia in the respiratory tract and numerous other organs. This leads to various characteristic symptoms and disease manifestations, primarily affecting the lungs (chronic persistent productive cough, bronchiectasis), the nose and paranasal sinuses (chronic persistent rhinitis or rhinosinusitis) as well as the middle ear (chronic otitis media, middle ear effusion). Moreover, PCD is associated with impaired fertility or lateralization defects (situs anomalies, congenital heart defects). The diagnostics of PCD are complex and require a combination of several sophisticated instrument-based diagnostic procedures. Through thorough history taking and evaluation, suspected cases can be comparatively well identified based on typical clinical features and referred to further diagnostics. In recent years, molecular genetic analysis through panel diagnostics or whole exome and whole genome sequencing, has gained in importance as this enables affected individuals to participate in disease-specific and genotype-specific clinical trials. Although the current treatment is purely symptomatic, the earliest possible diagnosis is crucial for connecting patients to specialized PCD centers, which can have a significant impact on the clinical course of the affected individuals.

Occurrence of COVID-19 in cystic fibrosis patients: a review

Cystic fibrosis (CF) is a genetic ailment caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. This autosomal recessive disorder is characterized by diverse pathobiological abnormalities, such as the disorder of CFTR channels in mucosal surfaces, caused by inadequate clearance of mucus and sputum, in addition to the malfunctioning of mucous organs. However, the primary motive of mortality in CF patients is pulmonary failure, which is attributed to the colonization of opportunistic microorganisms, formation of resistant biofilms, and a subsequent decline in lung characteristics. In December 2019, the World Health Organization (WHO) declared the outbreak of the radical coronavirus disease 2019 (COVID-19) as a worldwide public health crisis, which unexpectedly spread not only within China but also globally. Given that the respiration system is the primary target of the COVID-19 virus, it is crucial to investigate the impact of COVID-19 on the pathogenesis and mortality of CF patients, mainly in the context of acute respiratory distress syndrome (ARDS). Therefore, the goal of this review is to comprehensively review the present literature on the relationship between cystic fibrosis, COVID-19 contamination, and development of ARDS. Several investigations performed during the early stages of the virus outbreak have discovered unexpected findings regarding the occurrence and effectiveness of COVID-19 in individuals with CF. Contrary to initial expectancies, the rate of infection and the effectiveness of the virus in CF patients are lower than those in the overall population. This finding may be attributed to different factors, including the presence of thick mucus, social avoidance, using remedies that include azithromycin, the fairly younger age of CF patients, decreased presence of ACE-2 receptors, and the effect of CFTR channel disorder on the replication cycle and infectivity of the virus. However, it is important to notice that certain situations, which include undergoing a transplant, can also doubtlessly boost the susceptibility of CF patients to COVID-19. Furthermore, with an increase in age in CF patients, it is vital to take into account the prevalence of the SARS-CoV-2 virus in this population. Therefore, ordinary surveillance of CF patients is vital to evaluate and save the population from the capability of transmission of the virus given the various factors that contribute to the spread of the SARS-CoV-2 outbreak in this precise organization.

Ceragenin-mediated disruption of Pseudomonas aeruginosa biofilms

BACKGROUND

Microbial biofilms, as a hallmark of cystic fibrosis (CF) lung disease and other chronic infections, remain a desirable target for antimicrobial therapy. These biopolymer-based viscoelastic structures protect pathogenic organisms from immune responses and antibiotics. Consequently, treatments directed at disrupting biofilms represent a promising strategy for combating biofilm-associated infections. In CF patients, the viscoelasticity of biofilms is determined mainly by their polymicrobial nature and species-specific traits, such as Pseudomonas aeruginosa filamentous (Pf) bacteriophages. Therefore, we examined the impact of microbicidal ceragenins (CSAs) supported by mucolytic agents-DNase I and poly-aspartic acid (pASP), on the viability and viscoelasticity of mono- and bispecies biofilms formed by Pf-positive and Pf-negative P. aeruginosa strains co-cultured with Staphylococcus aureus or Candida albicans.

METHODS

The in vitro antimicrobial activity of ceragenins against P. aeruginosa in mono- and dual-species cultures was assessed by determining minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC). Inhibition of P. aeruginosa mono- and dual-species biofilms formation by ceragenins alone and in combination with DNase I or poly-aspartic acid (pASP) was estimated by the crystal violet assay. Additionally, the viability of the biofilms was measured by colony-forming unit (CFU) counting. Finally, the biofilms' viscoelastic properties characterized by shear storage (G') and loss moduli (G"), were analyzed with a rotational rheometer.

RESULTS

Our results demonstrated that ceragenin CSA-13 inhibits biofilm formation and increases its fluidity regardless of the Pf-profile and species composition; however, the Pf-positive biofilms are characterized by elevated viscosity and elasticity parameters.

CONCLUSION

Due to its microbicidal and viscoelasticity-modifying properties, CSA-13 displays therapeutic potential in biofilm-associated infections, especially when combined with mucolytic agents.

Mucoactive drugs and multiple applications in pulmonary disease therapy

Mucus is a complex polymeric hydrogel that serves as a critical defense in several organs. In the lungs, it provides a formidable barrier against inhaled particles such as microorganisms. In addition, mucus is essential for normal lung physiology, as it promotes immune tolerance and facilitates a normal commensal pulmonary microbiome. Hypersecretion of airway mucus is a characteristic of numerous respiratory diseases, such as Chronic Obstructive Pulmonary Disease (COPD) and Cystic Fibrosis (CF), and creates pulmonary obstruction, limiting the effectiveness of inhaled therapies. Due to those alterations, therapeutic strategies must be optimal to limit airway obstruction and restore pulmonary function. Mucoactive drugs are common therapeutic options and are classified into different groups depending on their modes of action, i.e., expectorants, mucokinetics, mucoregulators and mucolytics. This review focuses on mucoactive drugs and their modes of action. A special focus will be made on two challenging pulmonary pathologies: COPD and CF, and on their clinical studies conducted with mucoactive drugs.

Expert group recommendation on inhaled mucoactive drugs in pediatric respiratory diseases: an Indian perspective

Background

Currently, there are no guidelines or consensus statements about the usage of inhaled mucoactive drugs in pediatric respiratory disease conditions from an Indian perspective.

Objective

To develop a practical consensus document to help pediatricians in clinical decision-making when choosing an appropriate mucoactive drug for the management of specific respiratory disease conditions.

Methods

A committee of nine experts with significant experience in pediatric respiratory disease conditions and a microbiological expert constituted the panel. An electronic search of the PubMed/MEDLINE, Cochrane Library, Scopus, and Embase databases was undertaken to identify relevant articles. Various combinations of keywords such as inhaled, nebulized, mucoactive, mucolytic, mucokinetic, expectorants, mucoregulators, mucociliary clearance, respiratory disorders, pediatric, cystic fibrosis (CF), non-CF bronchiectasis, acute wheezing, asthma, primary ciliary dyskinesia (PCD), critically ill, mechanical ventilation, tracheomalacia, tracheobronchomalacia, esophageal atresia (EA), tracheoesophageal fistula (TEF), acute bronchiolitis, sputum induction, guideline, and management were used. Twelve questions were drafted for discussion. A roundtable meeting of experts was conducted to arrive at a consensus. The level of evidence and class of recommendation were weighed and graded.

Conclusions

Inhaled mucoactive drugs (hypertonic saline, dry powder mannitol, and dornase alfa) can enhance mucociliary clearance in children with CF. Experts opined that hypertonic saline could be beneficial in non-CF bronchiectasis, acute bronchiolitis, and PCD. The current state of evidence is inadequate to support the use of inhaled mucoactive drugs in asthma, acute wheezing, tracheomalacia, tracheobronchomalacia, and EA with TEF.

The natriuretic peptide receptor agonist osteocrin disperses Pseudomonas aeruginosa biofilm

Biofilms are highly tolerant to antimicrobials and host immune defense, enabling pathogens to thrive in hostile environments. The diversity of microbial biofilm infections requires alternative and complex treatment strategies. In a previous work we demonstrated that the human Atrial Natriuretic Peptide (hANP) displays a strong anti-biofilm activity toward Pseudomonas aeruginosa and that the binding of hANP by the AmiC protein supports this effect. This AmiC sensor has been identified as an analog of the human natriuretic peptide receptor subtype C (h-NPRC). In the present study, we evaluated the anti-biofilm activity of the h-NPRC agonist, osteocrin (OSTN), a hormone that displays a strong affinity for the AmiC sensor at least in vitro. Using molecular docking, we identified a pocket in the AmiC sensor that OSTN reproducibly docks into, suggesting that OSTN might possess an anti-biofilm activity as well as hANP. This hypothesis was validated since we observed that OSTN dispersed established biofilm of P. aeruginosa PA14 strain at the same concentrations as hANP. However, the OSTN dispersal effect is less marked than that observed for the hANP (-61% versus -73%). We demonstrated that the co-exposure of P. aeruginosa preformed biofilm to hANP and OSTN induced a biofilm dispersion with a similar effect to that observed with hANP alone suggesting a similar mechanism of action of these two peptides. This was confirmed by the observation that OSTN anti-biofilm activity requires the activation of the complex composed by the sensor AmiC and the regulator AmiR of the ami pathway. Using a panel of both P. aeruginosa laboratory reference strains and clinical isolates, we observed that the OSTN capacity to disperse established biofilms is highly variable from one strain to another. Taken together, these results show that similarly to the hANP hormone, OSTN has a strong potential to be used as a tool to disperse P. aeruginosa biofilms.

Drug delivery strategies for antibiofilm therapy

Although new antibiofilm agents have been developed to prevent and eliminate pathogenic biofilms, their widespread clinical use is hindered by poor biocompatibility and bioavailability, unspecific interactions and insufficient local concentrations. The development of innovative drug delivery strategies can facilitate penetration of antimicrobials through biofilms, promote drug dispersal and synergistic bactericidal effects, and provide novel paradigms for clinical application. In this Review, we discuss the potential benefits of such emerging techniques for improving the clinical efficacy of antibiofilm agents, as well as highlighting the existing limitations and future prospects for these therapies in the clinic.

Airway clearance in patients with neuromuscular disease

Airway clearance is a critical component of both maintenance of respiratory health and management of acute respiratory illnesses. The process of effective airway clearance begins with the recognition of secretions in the airway and culminates in expectoration or swallowing. There are multiple points on this continuum at which neuromuscular disease causes impaired airway clearance. This can result in an otherwise mild upper respiratory illness progressing unabated from an easily managed condition to a severe, life-threatening lower respiratory illness requiring intensive therapy for patient recovery. Even during periods of relative health, airway protective mechanisms can be compromised, and patients may have difficulty managing average quantities of secretions. This review summarizes airway clearance physiology and pathophysiology, mechanical and pharmacologic treatment modalities, and provides a practical approach for managing secretions in patients with neuromuscular disease. Neuromuscular disease is an umbrella term used to describe disorders that involve dysfunction of peripheral nerves, the neuromuscular junction, or skeletal muscle. Although this paper specifically reviews airway clearance pertaining to those with neuromuscular diseases (e.g., muscular dystrophy, spinal muscular atrophy, myasthenia gravis), most of its content is relevant to the management of patients with central nervous system disorders such as chronic static encephalopathy caused by trauma, metabolic or genetic abnormalities, congenital infection, or neonatal hypoxic-ischemic injury.

Air-Liquid interface cultures to model drug delivery through the mucociliary epithelial barrier

Epithelial cells from mucociliary portions of the airways can be readily grown and expanded in vitro. When grown on a porous membrane at an air-liquid interface (ALI) the cells form a confluent, electrically resistive barrier separating the apical and basolateral compartments. ALI cultures replicate key morphological, molecular and functional features of the in vivo epithelium, including mucus secretion and mucociliary transport. Apical secretions contain secreted gel-forming mucins, shed cell-associated tethered mucins, and hundreds of additional molecules involved in host defense and homeostasis. The respiratory epithelial cell ALI model is a time-proven workhorse that has been employed in various studies elucidating the structure and function of the mucociliary apparatus and disease pathogenesis. It serves as a critical milestone test for small molecule and genetic therapies targeting airway diseases. To fully exploit the potential of this important tool, numerous technical variables must be thoughtfully considered and carefully executed.

Nebulised hypertonic saline for cystic fibrosis

BACKGROUND

Hypertonic saline enhances mucociliary clearance and may lessen the destructive inflammatory process in the airways. This is an update of a previously published review.

OBJECTIVES

To investigate efficacy and tolerability of nebulised hypertonic saline treatment in people with cystic fibrosis (CF) compared to placebo or other treatments that enhance mucociliary clearance.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Cystic Fibrosis Trials Register, comprising references identified from comprehensive electronic database searches, handsearches of relevant journals and abstract books of conference proceedings. We also searched ongoing trials databases. Most recent search: 25 April 2022.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials assessing hypertonic saline compared to placebo or other mucolytic therapy, for any duration or dose regimen in people with CF (any age or disease severity).

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed all identified trials and data, and assessed trial quality. We assessed the certainty of the evidence using GRADE. For cross-over trials we stipulated a one-week washout period. We planned to use results from a paired analysis in the review, but this was only possible in one trial. For other cross-over trials, we chose to treat the trials as if they were parallel.

MAIN RESULTS

We included 24 trials (1318 participants, aged one month to 56 years); we excluded 29 trials, two trials are ongoing and six are awaiting classification. We judged 15 of the 24 included trials to have a high risk of bias due to participants' ability to discern the taste of the solutions. Hypertonic saline 3% to 7% versus placebo (stable disease) We are uncertain whether the regular use of nebulised hypertonic saline in stable lung disease leads to an improvement in forced expiratory volume in one second (FEV1) % predicted at four weeks, (mean difference (MD) 3.30%, 95% confidence interval (CI) 0.71 to 5.89; 4 trials, 246 participants; very low-certainty evidence). In preschool children we found no difference in lung clearance index (LCI) at four weeks, but a small improvement after 48 weeks of treatment with hypertonic saline compared to isotonic saline (MD -0.60, 95% CI -1.00 to -0.19; 2 trials, 192 participants). We are also uncertain whether hypertonic saline made a difference to mucociliary clearance, pulmonary exacerbations or adverse events compared to placebo. Hypertonic saline versus control (acute exacerbation) Two trials compared hypertonic saline to control, but only one provided data. There may be little or no difference in lung function measured by FEV1 % predicted after hypertonic saline compared to isotonic saline (MD 5.10%, 95% CI -14.67 to 24.87; 1 trial, 130 participants). Neither trial reported any deaths or measures of sputum clearance. There were no serious adverse events. Hypertonic saline versus rhDNase Three trials compared a similar dose of hypertonic saline to recombinant deoxyribonuclease (rhDNase); two trials (61 participants) provided data for inclusion in the review. We are uncertain whether there was an effect of hypertonic saline on FEV1 % predicted after three weeks (MD 1.60%, 95% CI -7.96 to 11.16; 1 trial, 14 participants; very low-certainty evidence). At three months, rhDNase may lead to a greater increase in FEV1 % predicted than hypertonic saline (5 mL twice daily) at 12 weeks in participants with moderate to severe lung disease (MD 8.00%, 95% CI 2.00 to 14.00; low-certainty evidence). We are uncertain whether adverse events differed between the two treatments. No deaths were reported. Hypertonic saline versus amiloride One trial (12 participants) compared hypertonic saline to amiloride but did not report on most of our outcomes. The trial found that there was no difference between treatments in measures of sputum clearance (very low-certainty evidence). Hypertonic saline compared with sodium-2-mercaptoethane sulphonate (Mistabron®) One trial (29 participants) compared hypertonic saline to sodium-2-mercaptoethane sulphonate. The trial did not measure our primary outcomes. There was no difference between treatments in any measures of sputum clearance, courses of antibiotics or adverse events (very low-certainty evidence). Hypertonic saline versus mannitol One trial (12 participants) compared hypertonic saline to mannitol, but did not report lung function at relevant time points for this review; there were no differences in sputum clearance, but mannitol was reported to be more 'irritating' (very low-certainty evidence). Hypertonic saline versus xylitol Two trials compared hypertonic saline to xylitol, but we are uncertain whether there is any difference in FEV1 % predicted or median time to exacerbation between groups (very low-certainty evidence). No other outcomes were reported in the review. Hypertonic saline 7% versus hypertonic saline 3% We are uncertain whether there was an improvement in FEV1 % predicted after treatment with 7% hypertonic saline compared with 3% (very low-certainty evidence).

AUTHORS' CONCLUSIONS

We are very uncertain if regular use of nebulised hypertonic saline by adults and children over the age of 12 years with CF results in an improvement in lung function after four weeks (three trials; very low-certainty evidence); there was no difference seen at 48 weeks (one trial; low-certainty evidence). Hypertonic saline improved LCI modestly in children under the age of six years. Evidence from one small cross-over trial in children indicates that rhDNase may lead to better lung function than hypertonic saline at three months; qualifying this, we highlight that while the study did demonstrate that the improvement in FEV1 was greater with daily rhDNase, there were no differences seen in any of the secondary outcomes. Hypertonic saline does appear to be an effective adjunct to physiotherapy during acute exacerbations of lung disease in adults. However, for the outcomes assessed, the certainty of the evidence ranged from very low to low at best, according to the GRADE criteria. The role of hypertonic saline in conjunction with cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy now needs to be considered, and future research needs to focus on this aspect.

Cystic Fibrosis: A Review

Importance

Cystic fibrosis, a genetic disorder defined by variants in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, affects more than 30 000 individuals in the US and approximately 89 000 worldwide. Absent or decreased function of the CFTR protein is associated with multiorgan dysfunction and shortened life expectancy.

Observations

CFTR is an anion channel in the apical membrane of epithelial cells. Loss of function leads to obstructed exocrine glands. Of people with cystic fibrosis in the US, approximately 85.5% have the gene variant F508del. Manifestations of cystic fibrosis in patients with the F508del gene variant begin in infancy with steatorrhea, poor weight gain, and respiratory symptoms (coughing, wheezing). As people with cystic fibrosis age, chronic respiratory bacterial infections cause loss of lung function and bronchiectasis. With the availability of universal newborn screening in multiple countries including the US, many people with cystic fibrosis are asymptomatic at diagnosis. With multidisciplinary care teams that included dietitians, respiratory therapists, and social workers, treatment of cystic fibrosis can slow disease progression. Median survival has improved from 36.3 years (95% CI, 35.1-37.9) in 2006 to 53.1 years (95% CI, 51.6-54.7) in 2021. Pulmonary therapies for patients with cystic fibrosis consist of mucolytics (eg, dornase alfa), anti-inflammatories (eg, azithromycin), and antibiotics (such as tobramycin delivered by a nebulizer). Four small molecular therapies, termed CFTR modulators, that facilitate CFTR production and/or function have received regulatory approval. Examples are ivacaftor and elexacaftor-tezacaftor-ivacaftor. For example, in patients with 1 F508del variant, the combination of ivacaftor, tezacaftor, and elexacaftor improved lung function from -0.2% in the placebo group to 13.6% (difference, 13.8%; 95% CI, 12.1%-15.4%) and decreased the annualized estimated rate of pulmonary exacerbations from 0.98 to 0.37 (rate ratio, 0.37; 95% CI, 0.25-0.55). Improved respiratory function and symptoms have lasted up to 144 weeks in postapproval observational studies. An additional 177 variants are eligible for treatment with the elexacaftor-tezacaftor-ivacaftor combination.

Conclusion

Cystic fibrosis affects approximately 89 000 people worldwide and is associated with a spectrum of disease related to exocrine dysfunction, including chronic respiratory bacterial infections and reduced life expectancy. First-line pulmonary therapies consist of mucolytics, anti-inflammatories, and antibiotics, and approximately 90% of people with cystic fibrosis who are 2 years or older may benefit from a combination of ivacaftor, tezacaftor, and elexacaftor.

Bladder cancer patients have increased NETosis and impaired DNaseI-mediated NET degradation that can be therapeutically restored in vitro

Background

Neutrophils, key players of the immune system, also promote tumor development through the formation of neutrophil extracellular traps (NETs) in a process called NETosis. NETs are extracellular networks of DNA, histones and cytoplasmic and granular proteins (calprotectin, myeloperoxidase, elastase, etc.) released by neutrophils upon activation. NETs regulate tumor growth while promoting angiogenesis and invasiveness, and tumor cells also stimulate NETosis. Although NETosis seems to be increased in cancer patients, an increase of NETs in plasma may also be mediated by an impaired degradation by plasma DNaseI, as evidenced in several immunological disorders like lupus nephritis. However, this has never been evidenced in bladder cancer (BC) patients. Herein, we aimed to evaluate the occurrence of increased NETosis in plasma and tumor tissue of BC patients, to ascertain whether it is mediated by a reduced DNaseI activity and degradation, and to in vitro explore novel therapeutic interventions.

Methods

We recruited 71 BC patients from whom we obtained a plasma sample before surgery and a formalin-fixed paraffin embedded tumor tissue sample, and 64 age- and sex-matched healthy controls from whom we obtained a plasma sample. We measured NETs markers (cell-free fDNA, calprotectin, nucleosomes and neutrophil elastase) and the DNaseI activity in plasma with specific assays. We also measured NETs markers in BC tissue by immunofluorescence. Finally, we evaluated the ability of BC and control plasma to degrade in vitro-generated NETs, and evaluated the performance of the approved recombinant human DNaseI (rhDNaseI, Dornase alfa, Pulmozyme^®, Roche) to restore the NET-degradation ability of plasma. In vitro experiments were performed in triplicate. Statistical analysis was conducted with Graphpad (v.8.0.1).

Results

NETosis occurs in BC tissue, more profusely in the muscle-invasive subtype (P<0.01), that with the worst prognosis. Compared to controls, BC patients had increased NETosis and a reduced DNaseI activity in plasma (P<0.0001), which leads to an impairment to degrade NETs (P<0.0001). Remarkably, this can be therapeutically restored with rhDNaseI to the level of healthy controls.

Conclusion

To the best of our knowledge, this is the first report demonstrating that BC patients have an increased NETosis systemically and in the tumor microenvironment, in part caused by an impaired DNaseI-mediated NET degradation. Remarkably, this defect can be therapeutically restored in vitro with the approved Dornase alfa, thus Pulmozyme^® could become a potential therapeutic tool to locally reduce BC progression.

Use of dornase alfa in pediatric patients without cystic fibrosis

OBJECTIVES

Literature regarding clinical benefits of dornase alfa (DNase) in pediatric patients without cystic fibrosis is lacking. In December 2020, the study institution implemented restrictions to limit DNase use in this patient population. The primary objective was adherence to DNase ordering restrictions. Secondary objectives included length of stay, respiratory function, and use of inhaled mucolytic agents.

METHODS

This single-center retrospective chart review included patients less than 18 years of age who received DNase one year prior to through one year after order restriction implementation. Data collected included patient demographics and respiratory clinical parameters. Dosing regimens for DNase, n-acetylcysteine, and hypertonic saline were collected, as well as changes in length of stay (LOS) and adherence to ordering restrictions.

RESULTS

Of 101 total DNase orders, 45 were placed after implementation of ordering restrictions and 16 (36%) met all ordering criteria. Hospital and intensive care unit (ICU) LOS after implementation of restrictions were not significantly different (p = 0.767 and p = 0.219, respectively). There was no significant change in patients' mean oxygenation index (p = 0.252) or FiO2% (p = 0.113) 24 hours after DA administration.

CONCLUSION

Respiratory function did not significantly change after DNase administration. Implementing restrictions on DNase did not impact intensive care unit or hospital LOS. Adherence to DNase ordering restrictions could be improved.

Brazilian guidelines for the pharmacological treatment of the pulmonary symptoms of cystic fibrosis. Official document of the Sociedade Brasileira de Pneumologia e Tisiologia (SBPT, Brazilian Thoracic Association)

Cystic fibrosis (CF) is a genetic disease that results in dysfunction of the CF transmembrane conductance regulator (CFTR) protein, which is a chloride and bicarbonate channel expressed in the apical portion of epithelial cells of various organs. Dysfunction of that protein results in diverse clinical manifestations, primarily involving the respiratory and gastrointestinal systems, impairing quality of life and reducing life expectancy. Although CF is still an incurable pathology, the therapeutic and prognostic perspectives are now totally different and much more favorable. The purpose of these guidelines is to define evidence-based recommendations regarding the use of pharmacological agents in the treatment of the pulmonary symptoms of CF in Brazil. Questions in the Patients of interest, Intervention to be studied, Comparison of interventions, and Outcome of interest (PICO) format were employed to address aspects related to the use of modulators of this protein (ivacaftor, lumacaftor+ivacaftor, and tezacaftor+ivacaftor), use of dornase alfa, eradication therapy and chronic suppression of Pseudomonas aeruginosa, and eradication of methicillin-resistant Staphylococcus aureus and Burkholderia cepacia complex. To formulate the PICO questions, a group of Brazilian specialists was assembled and a systematic review was carried out on the themes, with meta-analysis when applicable. The results obtained were analyzed in terms of the strength of the evidence compiled, the recommendations being devised by employing the GRADE approach. We believe that these guidelines represent a major advance to be incorporated into the approach to patients with CF, mainly aiming to favor the management of the disease, and could become an auxiliary tool in the definition of public policies related to CF.

New insights in pediatrics in 2021: choices in allergy and immunology, critical care, endocrinology, gastroenterology, genetics, haematology, infectious diseases, neonatology, neurology, nutrition, palliative care, respiratory tract illnesses and telemedicine

In this review, we report the developments across pediatric subspecialties that have been published in the Italian Journal of Pediatrics in 2021. We highlight advances in allergy and immunology, critical care, endocrinology, gastroenterology, genetics, hematology, infectious diseases, neonatology, neurology, nutrition, palliative care, respiratory tract illnesses and telemedicine.

Vesicle trafficking and vesicle fusion: mechanisms, biological functions, and their implications for potential disease therapy

Intracellular vesicle trafficking is the fundamental process to maintain the homeostasis of membrane-enclosed organelles in eukaryotic cells. These organelles transport cargo from the donor membrane to the target membrane through the cargo containing vesicles. Vesicle trafficking pathway includes vesicle formation from the donor membrane, vesicle transport, and vesicle fusion with the target membrane. Coat protein mediated vesicle formation is a delicate membrane budding process for cargo molecules selection and package into vesicle carriers. Vesicle transport is a dynamic and specific process for the cargo containing vesicles translocation from the donor membrane to the target membrane. This process requires a group of conserved proteins such as Rab GTPases, motor adaptors, and motor proteins to ensure vesicle transport along cytoskeletal track. Soluble N-ethyl-maleimide-sensitive factor (NSF) attachment protein receptors (SNARE)-mediated vesicle fusion is the final process for vesicle unloading the cargo molecules at the target membrane. To ensure vesicle fusion occurring at a defined position and time pattern in eukaryotic cell, multiple fusogenic proteins, such as synaptotagmin (Syt), complexin (Cpx), Munc13, Munc18 and other tethering factors, cooperate together to precisely regulate the process of vesicle fusion. Dysfunctions of the fusogenic proteins in SNARE-mediated vesicle fusion are closely related to many diseases. Recent studies have suggested that stimulated membrane fusion can be manipulated pharmacologically via disruption the interface between the SNARE complex and Ca²⁺ sensor protein. Here, we summarize recent insights into the molecular mechanisms of vesicle trafficking, and implications for the development of new therapeutics based on the manipulation of vesicle fusion.

Pathogen-Derived Nucleases: An Effective Weapon for Escaping Extracellular Traps

Since the 2004 publication of the first study describing extracellular traps (ETs) from human neutrophils, several reports have shown the presence of ETs in a variety of different animals and plants. ETs perform two important functions of immobilizing and killing invading microbes and are considered a novel part of the phagocytosis-independent, innate immune extracellular defense system. However, several pathogens can release nucleases that degrade the DNA backbone of ETs, reducing their effectiveness and resulting in increased pathogenicity. In this review, we examined the relevant literature and summarized the results on bacterial and fungal pathogens and parasites that produce nucleases to evade the ET-mediated host antimicrobial mechanism.

Inhibition of calcium-triggered secretion by hydrocarbon-stapled peptides

Membrane fusion triggered by Ca2+ is orchestrated by a conserved set of proteins to mediate synaptic neurotransmitter release, mucin secretion and other regulated exocytic processes1-4. For neurotransmitter release, the Ca2+ sensitivity is introduced by interactions between the Ca2+ sensor synaptotagmin and the SNARE complex5, and sequence conservation and functional studies suggest that this mechanism is also conserved for mucin secretion6. Disruption of Ca2+-triggered membrane fusion by a pharmacological agent would have therapeutic value for mucus hypersecretion as it is the major cause of airway obstruction in the pathophysiology of respiratory viral infection, asthma, chronic obstructive pulmonary disease and cystic fibrosis7-11. Here we designed a hydrocarbon-stapled peptide that specifically disrupts Ca2+-triggered membrane fusion by interfering with the so-called primary interface between the neuronal SNARE complex and the Ca2+-binding C2B domain of synaptotagmin-1. In reconstituted systems with these neuronal synaptic proteins or with their airway homologues syntaxin-3, SNAP-23, VAMP8, synaptotagmin-2, along with Munc13-2 and Munc18-2, the stapled peptide strongly suppressed Ca2+-triggered fusion at physiological Ca2+ concentrations. Conjugation of cell-penetrating peptides to the stapled peptide resulted in efficient delivery into cultured human airway epithelial cells and mouse airway epithelium, where it markedly and specifically reduced stimulated mucin secretion in both systems, and substantially attenuated mucus occlusion of mouse airways. Taken together, peptides that disrupt Ca2+-triggered membrane fusion may enable the therapeutic modulation of mucin secretory pathways.

Our evolving view of neutrophils in defining the pathology of chronic lung disease

Neutrophils are critical components of the body's immune response to infection, being loaded with a potent arsenal of toxic mediators and displaying immense destructive capacity. Given the potential of neutrophils to impart extensive tissue damage, it is perhaps not surprising that when augmented these cells are also implicated in the pathology of inflammatory diseases. Prominent neutrophilic inflammation is a hallmark feature of patients with chronic lung diseases such as chronic obstructive pulmonary disease, severe asthma, bronchiectasis and cystic fibrosis, with their numbers frequently associating with worse prognosis. Accordingly, it is anticipated that neutrophils are central to the pathology of these diseases and represent an attractive therapeutic target. However, in many instances, evidence directly linking neutrophils to the pathology of disease has remained somewhat circumstantial and strategies that have looked to reduce neutrophilic inflammation in the clinic have proved largely disappointing. We have classically viewed neutrophils as somewhat crude, terminally differentiated, insular and homogeneous protagonists of pathology. However, it is now clear that this does not do the neutrophil justice, and we now recognize that these cells exhibit heterogeneity, a pronounced awareness of the localized environment and a remarkable capacity to interact with and modulate the behaviour of a multitude of cells, even exhibiting anti-inflammatory, pro-resolving and pro-repair functions. In this review, we discuss evidence for the role of neutrophils in chronic lung disease and how our evolving view of these cells may impact upon our perceived assessment of their contribution to disease pathology and efforts to target them therapeutically.

Current and Future Treatments in Primary Ciliary Dyskinesia

Primary ciliary dyskinesia (PCD) is a rare genetic ciliopathy in which mucociliary clearance is disturbed by the abnormal motion of cilia or there is a severe reduction in the generation of multiple motile cilia. Lung damage ensues due to recurrent airway infections, sometimes even resulting in respiratory failure. So far, no causative treatment is available and treatment efforts are primarily aimed at improving mucociliary clearance and early treatment of bacterial airway infections. Treatment guidelines are largely based on cystic fibrosis (CF) guidelines, as few studies have been performed on PCD. In this review, we give a detailed overview of the clinical studies performed investigating PCD to date, including three trials and several case reports. In addition, we explore precision medicine approaches in PCD, including gene therapy, mRNA transcript and read-through therapy.

Hypertonic saline in people with cystic fibrosis: review of comparative studies and clinical practice

Cystic fibrosis (CF) is a multisystem disorder, caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. These cause a reduced secretion of chloride, a marked absorption of sodium and, therefore, of water, through the epithelium, resulting in the formation of thickened secretions in organs such as lung or pancreas. These viscous secretions lead to airway obstruction, chronic infection and inflammation resulting in progressive lung damage, bronchiectasis and eventual respiratory failure. Although the average life expectancy has increased over the last 30 years, lung disease is the most common cause of death in people with CF. For these reasons, the improvement of sputum clearance is a major therapeutic aim in CF and early initiation of airway clearance is widely recommended and implemented. Symptomatic mucolytic therapy today is mainly based on inhalation of DNase, hypertonic saline or mannitol, in combination with physiotherapy. Mucolytic agents break down the gel structure of mucus and therefore decrease its elasticity and viscosity, reducing the pulmonary exacerbation frequency and to improve and stabilize lung function. Nevertheless, high quality studies comparing these mucolytic drugs are still few, and the individual experiences of patients and caregivers explain the high variability of their use globally. This review will summarize the current knowledge on hypertonic saline in the treatment of CF lung disease. Furthermore, we report the real-world prescription of inhaled mucolytic agents in CF.

Neutrophil Extracellular Traps in Colorectal Cancer Progression and Metastasis

Neutrophils form sticky web-like structures known as neutrophil extracellular traps (NETs) as part of innate immune response. NETs are decondensed extracellular chromatin filaments comprising nuclear and cytoplasmic proteins. NETs have been implicated in many gastrointestinal diseases including colorectal cancer (CRC). However, the regulatory mechanisms of NET formation and potential pharmacological inhibitors in the context of CRC have not been thoroughly discussed. In this review, we intend to highlight roles of NETs in CRC progression and metastasis as well as the potential of targeting NETs during colon cancer therapy.