Bronchoscopic assessment of airway retention time of aerosolized xylitol

Randomized controlled study of aerosolized hypertonic xylitol versus hypertonic saline in hospitalized patients with pulmonary exacerbation of cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) lung disease is characterized by chronic bacterial infection and recurrent pulmonary exacerbations. Xylitol is a 5-carbon sugar that can lower the airway surface salt concentration and augment innate immunity. We examined the safety and efficacy of aerosolized xylitol use for 2 weeks in subjects hospitalized with a pulmonary exacerbation of CF.

METHODS

In a 2-week study, 60 subjects with cystic fibrosis and FEV₁ > 30% predicted were enrolled to receive aerosolized 7% hypertonic saline (4 ml) or 15% xylitol (5 ml) twice a day for 14 days. Outcomes assessed included change from baseline in FEV₁% predicted, change in sputum microbial density, revised CF quality of life questionnaire including the respiratory symptom score, time to next hospitalization for a pulmonary exacerbation, and frequency of adverse events.

RESULTS

59 subjects completed the study (one subject in the saline group withdrew before any study product administration). No significant differences were noted between the 2 arms in mean changes in lung function, sputum microbial density for Pseudomonas aeruginosa and Staphylococcus aureus, body weight, quality of life, and frequency of adverse events.

CONCLUSIONS

Aerosolized hypertonic xylitol was well-tolerated among subjects hospitalized for CF pulmonary exacerbation. Future studies examining efficacy for long term use in patients with CF lung disease would be worthwhile. The clinical trial registration number for this study is NCT00928135.

Current trends in topical therapies for chronic rhinosinusitis: update and literature review

INTRODUCTION

Chronic rhinosinusitis (CRS) affects millions of patients worldwide. The disease is multifactorial with influences including anatomic factors, immunological disturbances, and altered sinonasal microbiome. Although oral medications are effective in controlling some symptoms, they are associated with side effects and long-term use is not ideal. Thus, topical therapies have emerged as an alternative delivery method for localized, high-concentration medication with less side effects. Areas covered: This is a review of the various topical therapies available or under investigation for the management of CRS. Common medications such as saline, steroids, and antimicrobials will be discussed. Furthermore, additives including manuka honey, xylitol, surfactant, N-chlorotaurine, Dead Sea salt, and sodium hyaluronate will be addressed. Innovations in topical therapies, such as drug-eluting biomaterials and photodynamic therapy, will also be reviewed. Expert opinion: Although topical therapies provide a high dose of active substance at the site of disease, their efficacy in CRS is not clear. Topical saline and intranasal steroids appear to consistently demonstrate therapeutic benefits. However, other topical medications require further investigation to determine long-term clinical efficacy and safety. A better understanding of their effects on the sinonasal mucociliary system is needed before they become the standard of care in CRS.

Topical anti-infective sinonasal irrigations: update and literature review

BACKGROUND

Sinonasal anti-infective irrigations have emerged as a promising therapeutic modality in the comprehensive management of chronic rhinosinusitis (CRS), particularly in the context of recalcitrant disease. The purpose of this article was to delineate the current spectrum of topical anti-infective therapies available and evaluate their role in the treatment of CRS.

METHODS

A systematic literature review was performed on all studies investigating the use of topical antimicrobial solutions in the medical therapy of CRS. Anti-infective irrigations were stratified into topical antibacterial, antifungal, and additive preparations according to their composition and respective microbicidal properties.

RESULTS

The use of topical antibiotic irrigations has been supported by low-level studies in the treatment of refractory CRS, with optimal results achieved in patients who have undergone prior functional endoscopic sinus surgery and received culture-directed therapy. Multiple evidence-based reviews have not established any clinical benefit with the administration of topical antifungals, and their use is not currently recommended in the management of routine CRS. Topical additives including surfactants may be beneficial as adjunctive treatment for recalcitrant CRS, but additional research is needed to investigate their efficacy in comparison with other agents and establish safety profiles.

CONCLUSION

Topical anti-infective solutions are not recommended as first-line therapy for routine CRS but may be considered as a potential option for patients with refractory CRS who have failed traditional medical and surgical intervention. Additional research is necessary to determine which patient populations would derive the most benefit from each respective irrigation regimen and identify potential toxicities associated with prolonged use.

Protein composition of bronchoalveolar lavage fluid and airway surface liquid from newborn pigs

The airway mucosa and the alveolar surface form dynamic interfaces between the lung and the external environment. The epithelial cells lining these barriers elaborate a thin liquid layer containing secreted peptides and proteins that contribute to host defense and other functions. The goal of this study was to develop and apply methods to define the proteome of porcine lung lining liquid, in part, by leveraging the wealth of information in the Sus scrofa database of Ensembl gene, transcript, and protein model predictions. We developed an optimized workflow for detection of secreted proteins in porcine bronchoalveolar lavage (BAL) fluid and in methacholine-induced tracheal secretions [airway surface liquid (ASL)]. We detected 674 and 3,858 unique porcine-specific proteins in BAL and ASL, respectively. This proteome was composed of proteins representing a diverse range of molecular classes and biological processes, including host defense, molecular transport, cell communication, cytoskeletal, and metabolic functions. Specifically, we detected a significant number of secreted proteins with known or predicted roles in innate and adaptive immunity, microbial killing, or other aspects of host defense. In greatly expanding the known proteome of the lung lining fluid in the pig, this study provides a valuable resource for future studies using this important animal model of pulmonary physiology and disease.

Pharmacokinetic applications of microdevices and microsampling techniques

Pharmacokinetic studies require information regarding drug concentration at numerous time points during the process of absorption, distribution, metabolism and excretion. In order to obtain reproducible and good-quality data, the sampling method is as important as the bioanalytical method. A further difficulty in performing pharmacokinetic studies is related to the limited amount of sample that can be collected in some cases. Since analytical methods should interfere as little as possible with the investigated organism, microsampling techniques are a natural choice for pharmacokinetic studies. Accordingly, microdevices and microsampling approaches have been used increasingly in recent years for a wide variety of analytical applications, including analysis of drugs in biological samples. Such techniques not only reduce the amount of reagents needed for analysis, but are also faster and less disrupting. This review provides a brief overview of contemporary microsampling techniques: collection of small sample aliquots, ultrafiltration, microdialysis, solid-phase microextraction, biosensors and microfluidics. It is concluded that recent developments in microsampling and microdevices promise to streamline pharmacokinetic studies and bring bedside monitoring of therapeutic drugs into clinical practice.

Concentration of the antibacterial precursor thiocyanate in cystic fibrosis airway secretions

A recently discovered enzyme system produces antibacterial hypothiocyanite (OSCN(-)) in the airway lumen by oxidizing the secreted precursor thiocyanate (SCN(-)). Airway epithelial cultures have been shown to secrete SCN(-) in a CFTR-dependent manner. Thus, reduced SCN(-) availability in the airway might contribute to the pathogenesis of cystic fibrosis (CF), a disease caused by mutations in the CFTR gene and characterized by an airway host defense defect. We tested this hypothesis by analyzing the SCN(-) concentration in the nasal airway surface liquid (ASL) of CF patients and non-CF subjects and in the tracheobronchial ASL of CFTR-ΔF508 homozygous pigs and control littermates. In the nasal ASL, the SCN(-) concentration was ~30-fold higher than in serum independent of the CFTR mutation status of the human subject. In the tracheobronchial ASL of CF pigs, the SCN(-) concentration was somewhat reduced. Among human subjects, SCN(-) concentrations in the ASL varied from person to person independent of CFTR expression, and CF patients with high SCN(-) levels had better lung function than those with low SCN(-) levels. Thus, although CFTR can contribute to SCN(-) transport, it is not indispensable for the high SCN(-) concentration in ASL. The correlation between lung function and SCN(-) concentration in CF patients may reflect a beneficial role for SCN(-).