Biomarkers in Exhaled Breath Condensate Are Not Predictive for Pulmonary Exacerbations in Children with Cystic Fibrosis: Results of a One-Year Observational Study

The Non-Invasive Detection of Pulmonary Exacerbations in Disorders of Mucociliary Clearance with Breath Analysis: A Systematic Review

Background: Disorders of mucociliary clearance, such as cystic fibrosis (CF), primary ciliary dyskinesia (PCD) and bronchiectasis of unknown origin, are characterised by periods with increased respiratory symptoms, referred to as pulmonary exacerbations. These exacerbations are hard to predict and associated with lung function decline and the loss of quality of life. To optimise treatment and preserve lung function, there is a need for non-invasive and reliable methods of detection. Breath analysis might be such a method. Methods: We systematically reviewed the existing literature on breath analysis to detect pulmonary exacerbations in mucociliary clearance disorders. Extracted data included the study design, technique of measurement, definition of an exacerbation, identified compounds and diagnostic accuracy. Results: Out of 244 identified articles, 18 were included in the review. All studies included patients with CF and two also with PCD. Age and the definition of exacerbation differed between the studies. There were five that measured volatile organic compounds (VOCs) in exhaled breath using gas chromatography with mass spectrometry, two using an electronic nose and eleven measured organic compounds in exhaled breath condensate. Most studies showed a significant correlation between pulmonary exacerbations and one or multiple compounds, mainly hydrocarbons and cytokines, but the validation of these results in other studies was lacking. Conclusions: The detection of pulmonary exacerbations by the analysis of compounds in exhaled breath seems possible but is not near clinical application due to major differences in results, study design and the definition of an exacerbation. There is a need for larger studies, with a longitudinal design, international accepted definition of an exacerbation and validation of the results in independent cohorts.

Mapping targetable inflammation and outcomes with cystic fibrosis biomarkers

Cystic fibrosis is characterized by an overly exuberant neutrophilic inflammatory response to pathogens and other stimuli that starts very early in disease. The overwhelming nature of this response is a primary cause of remodeling and destruction of the airways, suggesting that anti-inflammatory therapies could be beneficial in CF. However, finding therapies that can effectively reduce the inflammatory response without compromising host defenses remains elusive. New approaches towards mapping inflammatory targets promise to aid in developing novel therapeutic strategies and improve outcomes in individuals with CF.

Clinically Promising Biomarkers in Cystic Fibrosis Pulmonary Exacerbations

Cystic fibrosis is a complex genetic disease hallmarked by repetitive infectious exacerbations that leads to destruction of airway architecture, acute on chronic inflammatory changes, and deterioration in lung function. Predicting an exacerbation may help preempt some of these changes by the initiation of swift antibiotic and anti-inflammatory therapy. A search for biomarkers that could predict exacerbations or help guide duration of antibiotic therapy is being aggressively sought. In this review, we discuss the most recent and promising biomarkers that hopefully will assist in the future management of the CF patient.

Special considerations for the treatment of pulmonary exacerbations in children with cystic fibrosis

INTRODUCTION

Cystic fibrosis (CF) is a disease characterized by recurrent flares of respiratory symptoms, known as pulmonary exacerbations (PExs), which have a cumulative, detrimental effect on lung function decline and overall mortality. Although much research has been done on the effects of PExs in adults with CF, considerably less is known about these events in young children with CF. Areas covered: This review describes the typical presentation of PExs in children and their impact on long-term clinical outcomes. Traditional and new monitoring techniques, such as pulmonary function testing using multiple breath washout, radiographic modalities and microbiological screening methods are reviewed. Finally, the choice, administration and duration of antimicrobial treatment as well as the potential use of antiviral therapy is discussed. Expert commentary: Although it is now well recognized that a significant proportion of patients do not recover their lung function following PExs, to date, little progress has been made to improve outcomes in this group. Additional therapies, to complement antimicrobials, may be required to treat infection and inflammation during PExs. Trials of anti-inflammatories such as corticosteroids or other novel drugs need to be done in the setting of PExs with the goal of complete lung function recovery for all individuals with CF.