BRONCHOSPASM CAUSED BY ACETYLCYSTEINE IN CHILDREN WITH BRONCHIAL ASTHMA

Glutathione and bicarbonate nanoparticles improve mucociliary transport in cystic fibrosis epithelia

INTRODUCTION

Cystic fibrosis (CF) airway disease is characterized by thick mucus and impaired mucociliary transport (MCT). Loss of functional cystic fibrosis transmembrane receptor (CFTR) leads to acidification and oxidation of airway surface mucus. Replacing bicarbonate (HCO3 -) topically fails due to rapid reabsorption and neutralization, while the scavenging antioxidant, glutathione sulfhydryl (GSH), is also rapidly degraded. The objective of this study is to investigate GSH/NaHCO3 nanoparticles as novel strategy for CF airway disease.

METHODS

GSH/NaHCO3 poly (lactic-co-glycolic acid) nanoparticles were tested on primary CF (F508del/F508del) epithelial cultures to evaluate dose-release curves, surface pH, toxicity, and MCT indices using micro-optical coherence tomography. In vivo tests were performed in three rabbits to assess safety and toxicity. After 1 week of daily injections, histopathology, computed tomography (CT), and blood chemistries were performed and compared to three controls. Fluorescent nanoparticles were injected into a rabbit with maxillary sinusitis and explants visualized with confocal microscopy.

RESULTS

Sustained release of GSH and HCO3 - with no cellular toxicity was observed over 2 weeks. Apical surface pH gradually increased from 6.54 ± 0.13 (baseline) to 7.07 ± 0.10 (24 h) (p < 0.001) and 6.87 ± 0.05 at 14 days (p < 0.001). MCT, ciliary beat frequency, and periciliary liquid were significantly increased. When injected into the maxillary sinuses of rabbits, there were no changes to histology, CT, or blood chemistries. Nanoparticles penetrated rabbit sinusitis mucus on confocal microscopy.

CONCLUSION

Findings suggest that GSH/NaHCO3 - nanoparticles are a promising treatment option for viscous mucus in CF and other respiratory diseases of mucus obstruction such as chronic rhinosinusitis.

Mucolytic treatment of chronic rhinosinusitis in a murine model of primary ciliary dyskinesia

Background: Genetic defects in motile cilia cause primary ciliary dyskinesia (PCD), a rare disease with no specific therapeutics. Individuals with PCD often have impaired fertility and laterality defects and universally suffer from upper and lower airway diseases. Chronic rhinosinusitis is a universal feature of PCD, and mucus accumulation and subsequent infections of the sinonasal cavity cause significant morbidity in individuals with PCD. Despite this, there are no approved treatments that specifically target mucus. Objective: The goals of this study were to determine whether computed tomography (CT) imaging could be used to quantify mucus accumulation and whether the use of a mucolytic agent to reduce disulfide cross-links present in mucins would improve the effectiveness of nasal lavage at removing mucus in a murine model of PCD. Methods: Adult mice with a deletion of the axonemal dynein Dnaic1 were imaged using CT scanning to characterize mucus accumulation. The animals were then treated by nasal lavage with saline, with/without the disulfide-reducing agent tris(2-carboxyethyl)phosphine. Post-treatment CT scans were used to quantify improvement in the sinonasal cavity. Results: Mucus accumulation in the nasal cavity was readily quantified by CT. Compared to sham-treated control animals, nasal lavage with/without a mucolytic agent resulted in a significant reduction of accumulated mucus (p < 0.01). Treatment with the mucolytic agent showed a greater reduction of accumulated mucus than treatment with saline alone. Conclusion: The results suggest that inclusion of a mucolytic agent may increase the effectiveness of nasal lavage at reducing mucus burden in PCD.

Role of the mucins in pathogenesis of COPD: implications for therapy

Introduction: Evidence accumulated in the last decade has started to reveal the enormous complexity in the expression, interactions and functions of the large number of different mucins present in the different compartments of the human lower airways. This occurs both in normal subjects and in COPD patients in different clinical phases and stages of severity.Areas covered: We review the known physiological mechanisms that regulate mucin production in human lower airways of normal subjects, the changes in mucin synthesis/secretion in COPD patients and the clinical efficacy of drugs that modulate mucin synthesis/secretion.Expert opinion: It is evident that the old simplistic concept that mucus hypersecretion in COPD patients is associated with negative clinical outcomes is not valid and that the therapeutic potential of 'mucolytic drugs' is under-appreciated due to the complexity of the associated molecular network(s). Likewise, our current knowledge of the effects of the drugs already available on the market that target mucin synthesis/secretion/structure in the lower airways is extremely limited and often indirect and more well-controlled clinical trials are needed in this area.

Airway Mucus and Asthma: The Role of MUC5AC and MUC5B

Asthma is characterized by mucus abnormalities. Airway epithelial hyperplasia and metaplasia result in changes in stored and secreted mucin and the production of a pathologic mucus gel. Mucus transport is impaired, culminating in mucus plugging and airway obstruction—a major cause of morbidity in asthma. The polymeric mucins MUC5AC and MUC5B are integral components of airway mucus. MUC5AC and MUC5B gene expression is altered in asthma, and recent work sheds light on their contribution to asthma pathogenesis. Herein, we review our current understanding of the role of MUC5AC and MUC5B in mucus dysfunction in asthma.

Management of Pulmonary Disease in Patients with Cystic Fibrosis

Cystic fibrosis is the most common, life-shortening autosomal recessive disease, affecting approximately 1 in 3400 live births in the United States. Gastrointestinal and pulmonary manifestations are most common. With the introduction of pancreatic enzyme and vitamin supplementation, lung disease accounts for the vast majority of morbidity and mortality in patients with cystic fibrosis. The lungs of cystic fibrosis patients are essentially normal at birth but demonstrate evidence of airway inflammation and infection in early infancy. A vicious cycle of inflammation, infection and obstruction ultimately leads to destruction of airways, impairment of gas exchange and death.

Current pharmacological management of pulmonary disease targets reducing airway obstruction, controlling infection and more recently, controlling inflammation. An increased recovery of unusual and highly resistant bacteria from patients with more advanced disease has been observed. Aggressive treatment of acute pulmonary exacerbations with combination antibiotic therapy for two to three weeks has shown pronounced beneficial effects. The routine use of prophylactic antistaphylococcal antibiotics is still controversial.

Although current pharmacologic treatment is symptomatic, new agents are being developed and studied that target the underlying defect in the CFTR protein. This review focuses on current pharmacologic management of pulmonary disease in patients with cystic fibrosis and the role of new agents emerging for the treatment of this disease.

Appropriateness in allergic respiratory diseases health care in Italy: definitions and organizational aspects

In a historical period in which sustainability of the National Health Service is mandatory because of the international economical situation, the limited available resources at national level and the tendency of passing from a “population medicine” model towards the concept of “individualized medicine”, the debate on appropriateness of medical and surgical procedures is of central importance. The choosing wisely campaign, started in United States in 2012 and then spread all over the world, tries to summarize which are the most inappropriate procedures for each medical and surgical speciality; as far as allergic respiratory diseases, the most relevant Italian societies and the American Academy defined the allergological procedures with the highest probability of inappropriateness. In Italy, a recent decree of the Ministry of Health defined a list of more than 200 procedures that will be considered as inappropriate in certain conditions; many of these procedures concern allergology, including allergic respiratory diseases. In this commentary we discuss the above mentioned decree and the concept of appropriateness in the field of allergic respiratory diseases, trying to figure out some practical considerations based on the current health resources available in the field of allergology in Italy.

Preventive nebulization of mucolytic agents and bronchodilating drugs in invasively ventilated intensive care unit patients (NEBULAE): study protocol for a randomized controlled trial

Background

Preventive nebulization of mucolytic agents and bronchodilating drugs is a strategy aimed at the prevention of sputum plugging, and therefore atelectasis and pneumonia, in intubated and ventilated intensive care unit (ICU) patients. The present trial aims to compare a strategy using the preventive nebulization of acetylcysteine and salbutamol with nebulization on indication in intubated and ventilated ICU patients.

Methods/Design

The preventive nebulization of mucolytic agents and bronchodilating drugs in invasively ventilated intensive care unit patients (NEBULAE) trial is a national multicenter open-label, two-armed, randomized controlled non-inferiority trial in the Netherlands. Nine hundred and fifty intubated and ventilated ICU patients with an anticipated duration of invasive ventilation of more than 24 hours will be randomly assigned to receive either a strategy consisting of preventive nebulization of acetylcysteine and salbutamol or a strategy consisting of nebulization of acetylcysteine and/or salbutamol on indication. The primary endpoint is the number of ventilator-free days and surviving on day 28. Secondary endpoints include ICU and hospital length of stay, ICU and hospital mortality, the occurrence of predefined pulmonary complications (acute respiratory distress syndrome, pneumonia, large atelectasis and pneumothorax), and the occurrence of predefined side effects of the intervention. Related healthcare costs will be estimated in a cost-benefit and budget-impact analysis.

Discussion

The NEBULAE trial is the first randomized controlled trial powered to investigate whether preventive nebulization of acetylcysteine and salbutamol shortens the duration of ventilation in critically ill patients.

Trial registration

NCT02159196, registered on 6 June 2014.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-015-0865-0) contains supplementary material, which is available to authorized users.

Mucolytics for intubated asthmatic children: a national survey of United kingdom paediatric intensive care consultants

Aim. The extent to which mucolytics are utilised in mechanically ventilated asthmatic children is unknown. We sought to establish current practice in the United Kingdom (UK) including choice of mucolytic, dose, and frequency of utilisation. Methods. A national electronic survey was distributed to UK consultants during April and May 2014. We were able to identify 168 PICU consultants at 25 institutions to whom we were able to electronically distribute a survey, representing an estimated 81% of UK NHS PICU consultants. Results. Replies were received from 87 consultants at 21 institutions (response rate = 52%). Recombinant human DNase (rhDNase) does get administered by 63% of clinicians, with 54% and 19% that administer hypertonic saline or N-acetylcysteine, respectively. Of those that do administer rhDNase the majority (48%) dilute it with 0.9% saline and blindly administer it, whereas 35% administer rhDNase under bronchoscopic guidance and 17% judge the necessity for bronchoscopy according to clinical severity. 25 respondents described 7 different methods to calculate rhDNase dose. A majority (87%) of respondents expressed an interest to consider enrolling patients into an RCT that evaluates rhDNase. Conclusion. Significant variation exists regarding the necessity for mucolytics, choice of agent, optimal route, and dose in intubated asthmatic children.

Secretion properties, clearance, and therapy in airway disease

Chronic airway diseases like cystic fibrosis, chronic bronchitis, asthma, diffuse panbronchiolitis, and bronchiectasis are all associated with chronic inflammation. The airway mucosa responds to infection and inflammation in part by surface mucous (goblet) cell and submucosal gland hyperplasia and hypertrophy with mucus hypersecretion. Products of inflammation including neutrophil derived DNA and filamentous actin, effete cells, bacteria, and cell debris all contribute to mucus purulence and, when this is expectorated it is called sputum. Mucus is usually cleared by ciliary movement, and sputum is cleared by cough.

These airway diseases each are associated with the production of mucus and sputum with characteristic composition, polymer structure, and biophysical properties. These properties change with the progress of the disease making it possible to use sputum analysis to identify the potential cause and severity of airway diseases. This information has also been important for the development of effective mucoactive therapy to promote airway hygiene.

"Pills" and the air passages

Aspiration of a medication in the airways in any form produces a variety of adverse effects, both local and systemic. Furthermore, specific reaction of the airways to each type of pill strongly affects the outcome. It is crucial for pulmonologists and emergency medicine specialists to acknowledge this clinical entity. In addition, airways have been increasingly used to deliver medications such as insulin and prostacycline. These aerosolized medications can also cause local as well as systemic side effects. We review the local and systemic reactions of these "pills" accessing the airways either by incidental aspiration or iatrogenic administration. We address clinical presentation, mechanism of injury, diagnosis, and management of complications of these pills in the air passages.

Acetylcysteine and carbocysteine for acute upper and lower respiratory tract infections in paediatric patients without chronic broncho-pulmonary disease

BACKGROUND

Acetylcysteine and carbocysteine are the most commonly prescribed mucolytic drugs in Brazil and many European and African countries. To our knowledge, no systematic review has been published on their efficacy and safety for acute upper and lower respiratory tract infections (RTIs) in children without chronic broncho-pulmonary disease.

OBJECTIVES

The objective was to assess the efficacy and safety and to establish a benefit-risk ratio of acetylcysteine and carbocysteine as symptomatic treatments for acute upper and lower RTIs in paediatric patients without chronic broncho-pulmonary disease.

SEARCH METHODS

We searched CENTRAL (2013, Issue 2), MEDLINE (1966 to February week 3, 2013), EMBASE (1980 to March 2013), Micromedex (2010), Pascal (1987 to 2004) and Science Citation Index (1974 to March 2013).

SELECTION CRITERIA

To study efficacy, we used randomised controlled trials (RCTs) comparing the use of acetylcysteine or carbocysteine versus placebo, either alone or as an add-on therapy. To study safety, we used trials comparing acetylcysteine or carbocysteine versus active treatment or no treatment and case reports.

DATA COLLECTION AND ANALYSIS

In this review update two review authors (YD, MC), with help from a colleague, extracted data and assessed trial quality. We performed a subgroup analysis of children younger than two years of age.

MAIN RESULTS

We included six trials involving 497 participants to study efficacy. They showed some benefit (e.g. reduction of cough at day seven) from mucolytic agents, although differences were of little clinical relevance. No conclusion was drawn about the subgroup of infants younger than two years because data were unavailable. Thirty-four studies, including the previous six trials involving 2064 children, were eligible to study safety. Overall safety was good but very few data were available to evaluate safety in infants younger than two years. However, 59 cases of paradoxically increased bronchorrhoea observed in infants were reported to the French pharmacovigilance system.

AUTHORS' CONCLUSIONS

The results have to be interpreted with caution because they are based on a limited number of participants included in studies whose methodological quality is questionable. Acetylcysteine and carbocysteine seem to have a limited efficacy and appear to be safe in children older than two years. These results should take into consideration the fact that acetylcysteine and carbocysteine are prescribed for self limiting diseases (for example, acute cough, bronchitis). Given strong concerns about safety, these drugs should only be used for acute upper and lower RTIs in the context of a RCT with regards to children younger than two years.

Acetylcysteine and carbocysteine for acute upper and lower respiratory tract infections in paediatric patients without chronic broncho-pulmonary disease

BACKGROUND

Acetylcysteine and carbocysteine are the most commonly prescribed mucolytic drugs in many European countries. To our knowledge, no systematic review has been published on their efficacy and safety for acute upper and lower respiratory tract infections (ARTIs) in children without chronic broncho-pulmonary disease.

OBJECTIVES

The objective was to assess the efficacy and safety and to establish a benefit-risk ratio of acetylcysteine and carbocysteine as symptomatic treatments for ARTIs in children without chronic broncho-pulmonary disease.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, issue 4) which contains the Acute Respiratory Infections (ARI) Group's Specialized Register, MEDLINE (1966 to 2008), EMBASE (1980 to 2008); Micromedex (2008), Pascal (1987 to 2004), and Science Citation Index (1974 to 2008).

SELECTION CRITERIA

To study efficacy, we used randomised controlled trials (RCTs) comparing the use of acetylcysteine or carbocysteine versus placebo either alone or as an add-on therapy.To study safety, we also used trials comparing the use of acetylcysteine or carbocysteine versus active treatment or no treatment and case reports.

DATA COLLECTION AND ANALYSIS

At least two review authors extracted data and assessed trial quality. We performed a subgroup analysis of children younger than two years of age.

MAIN RESULTS

Six trials involving 497 participants were included to study efficacy. They showed some benefit from mucolytic agents, although differences were of little clinical relevance. No conclusion was drawn about the subgroup of infants younger than two years because the data were unavailable. Thirty-four studies including the previous six trials involving 2064 children were eligible to study safety. Overall safety was good but very few data were available to evaluate safety in infants younger than two years. However, 48 cases of paradoxically increased bronchorrhoea observed in infants were reported to the French pharmacovigilance system.

AUTHORS' CONCLUSIONS

The results of this review have to be interpreted with caution because it was based on a limited number of participants included in studies whose methodological quality is questionable. Acetylcysteine and carbocysteine seem to have a limited efficacy and appear to be safe in children older than two years. These results should take into consideration the fact that acetylcysteine and carbocysteine are prescribed for self-limiting diseases (for example, acute cough, bronchitis). Regarding children younger than two years, given concerns about safety, these drugs should only be used for ARTIs in the context of an RCT.

Pharmacotherapy of impaired mucociliary clearance in non-CF pediatric lung disease. A review of the literature

Mucoactive agents are used to treat a variety of lung diseases involving impaired mucociliary clearance or mucus hypersecretion. The mucoactive agents studied most frequently are N-acetylcysteine (NAC), recombinant human DNase (rhDNase), and hypertonic saline. Studies on the efficacy of these have been mainly conducted in adults, and in patients with cystic fibrosis (CF). The exact role of mucoactive agents in children with non-CF lung disease is not well established. We present an overview of the current literature reporting clinical outcome measures of treatment with NAC, rhDNase, and hypertonic saline in children.