Mucus Clearance Research Articles

Axonemal structures reveal mechanoregulatory and disease mechanisms

Motile cilia and flagella beat rhythmically on the surface of cells to power the flow of fluid and to enable spermatozoa and unicellular eukaryotes to swim. In humans, defective ciliary motility can lead to male infertility and a congenital disorder called primary ciliary dyskinesia (PCD), in which impaired clearance of mucus by the cilia causes chronic respiratory infections1. Ciliary movement is generated by the axoneme, a molecular machine consisting of microtubules, ATP-powered dynein motors and regulatory complexes2. The size and complexity of the axoneme has so far prevented the development of an atomic model, hindering efforts to understand how it functions. Here we capitalize on recent developments in artificial intelligence-enabled structure prediction and cryo-electron microscopy (cryo-EM) to determine the structure of the 96-nm modular repeats of axonemes from the flagella of the alga Chlamydomonas reinhardtii and human respiratory cilia. Our atomic models provide insights into the conservation and specialization of axonemes, the interconnectivity between dyneins and their regulators, and the mechanisms that maintain axonemal periodicity. Correlated conformational changes in mechanoregulatory complexes with their associated axonemal dynein motors provide a mechanism for the long-hypothesized mechanotransduction pathway to regulate ciliary motility. Structures of respiratory-cilia doublet microtubules from four individuals with PCD reveal how the loss of individual docking factors can selectively eradicate periodically repeating structures.

Personalising airway clearance in chronic suppurative lung diseases: a scoping review.

Personalised airway clearance techniques are commonly recommended to augment mucus clearance in chronic suppurative lung diseases. It is unclear what current literature tells us about how airway clearance regimens should be personalised. This scoping review explores current research on airway clearance technique in chronic suppurative lung diseases, to establish the extent and type of guidance in this area, identify knowledge gaps and determine the factors which physiotherapists should consider when personalising airway clearance regimens. Systematic searching of online databases (MEDLINE, EMBASE, CINAHL, PEDro, Cochrane, Web of Science) was used to identify full-text publications in the last 25 years that described methods of personalising airway clearance techniques in chronic suppurative lung diseases. Items from the TIDieR framework provided a priori categories which were modified based on the initial data to develop a "Best-fit" framework for data charting. The findings were subsequently transformed into a personalisation model. A broad range of publications were identified, most commonly general review papers (44%). The items identified were grouped into seven personalisation factors: physical, psychosocial, airway clearance technique (ACT) type, procedures, dosage, response and provider. As only two divergent models of ACT personalisation were found, the personalisation factors identified were then used to develop a model for physiotherapists. The personalisation of airway clearance regimens is widely discussed in the current literature, which provides a range of factors that should be considered. This review summarises the current literature, organising findings into a proposed airway clearance personalisation model, to provide clarity in this field.

Long-Term High Flow Nasal Cannula Therapy in Primary and Secondary Bronchiectasis.

Bronchiectasis is the consequence of chronic bronchial inflammation, inappropriate mucus clearance, bacterial colonization, and recurrent or chronic infection. High flow therapy (HFT) is a type of non-invasive respiratory therapy, usually delivered through a nasal cannula interface (HFNC). It delivers heated and humidified air with a stable fraction of inspired oxygen and a wide range of possible flow rates. Determine the effectiveness of HFNC as add-on therapy in adult primary and secondary bronchiectasis with frequent acute exacerbations (AEs) and/or hospitalizations. This is a single-center crossover study on long-term home therapy with HFNC in adult bronchiectasis. Pharmacological therapy included pulse therapy with mucolytics and bronchodilators. After one year, all patients were switched to additional HFNC. The temperature range was 31-37 °C. The flow range was 35-60 L/m. FiO2 was 0.21. Seventy-eight patients completed the follow-up; 54% were females; the median age was 70 years (IQR 60-76). The etiology of bronchiectasis was mainly post-infective (51%), COPD related (26%), and congenital (11%). AEs at baseline were 2.81 (±2.15). A significant reduction in AEs was observed after 24 months with a mean of 0.45 (±0.66) (f-ratio value 79.703. p-value < 0.00001). No significant difference was observed after HFNC therapy on FEV1 (2.39 ± 0.87 vs. 2.55 ± 0.82; f-ratio 0.79. p-value 0.45) and FVC (2.73 ± 0.88 vs. 2.84 ± 0.90; f-ratio 0.411. p-value 0.66). A significant reduction in mMRC score was observed after HFNC therapy (2.40 ± 0.81 vs. 0.97 ± 0.97 at 2 months vs. 0.60 ± 0.78 at 24 months; f-ratio value 95.512. p-value < 0.00001). HFNC is a well-tolerated add-on therapy for adult bronchiectasis. Dyspnea improved after 2 months and further after 2 years. The exacerbation rate decreased during the 2 years follow-up. No significant difference was observed in lung function.

Normalizing salt content by mixing native human airway mucus samples normalizes sample rheology.

Across the globe, millions of people are affected by muco-obstructive pulmonary diseases like cystic fibrosis, asthma, and chronic obstructive pulmonary disease. In MOPDs, the airway mucus becomes hyperconcentrated, increasing viscoelasticity and impairing mucus clearance. Research focused on treatment of MOPDs requires relevant sources of airway mucus both as a control sample type and as a basis for manipulation to study the effects of additional hyperconcentration, inflammatory milieu, and biofilm growth on the biochemical and biophysical properties of mucus. Endotracheal tube mucus has been identified as a prospective source of native airway mucus given its several advantages over sputum and airway cell culture mucus such as ease of access and in vivo production that includes surface airway and submucosal gland secretions. Still, many ETT samples suffer from altered tonicity and composition from either dehydration, salivary dilution, or other contamination. Herein, the biochemical compositions of ETT mucus from healthy human subjects were determined. Samples were characterized in terms of tonicity, pooled, and restored to normal tonicity. Salt-normalized ETT mucus exhibited similar concentration-dependent rheologic properties as originally isotonic mucus. This rheology agreed across spatial scales and with previous reports of the biophysics of ETT mucus. This work affirms previous reports of the importance of salt concentration on mucus rheology and presents methodology to increase yield native airway mucus samples for laboratory use and manipulation.

An operative framework to model mucus clearance in silico by coupling cilia motion with the liquid environment.

Mucociliary clearance is the first defense mechanism of the respiratory tract against inhaled particles. This mechanism is based on the collective beating motion of cilia at the surface of epithelial cells. Impaired clearance, either caused by malfunctioning or absent cilia, or mucus defects, is a symptom of many respiratory diseases. Here, by exploiting the lattice Boltzmann particle dynamics technique, we develop a model to simulate the dynamics of multiciliated cells in a two-layer fluid. First, we tuned our model to reproduce the characteristic length- and time-scales of the cilia beating. We then check for the emergence of the metachronal wave as a consequence of hydrodynamic mediated correlations between beating cilia. Finally, we tune the viscosity of the top fluid layer to simulate the mucus flow upon cilia beating, and evaluate the pushing efficiency of a carpet of cilia. With this work, we build a realistic framework that can be used to explore several important physiological aspects of mucociliary clearance.

Active cycle of breathing technique for cystic fibrosis.

People with cystic fibrosis (CF) experience chronic airway infections as a result of mucus buildup within the lungs. Repeated infections often cause lung damage and disease. Airway clearance therapies aim to improve mucus clearance, increase sputum production, and improve airway function. The active cycle of breathing technique (ACBT) is an airway clearance method that uses a cycle of techniques to loosen airway secretions including breathing control, thoracic expansion exercises, and the forced expiration technique. This is an update of a previously published review. To compare the clinical effectiveness of ACBT with other airway clearance therapies in CF. We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched clinical trials registries and the reference lists of relevant articles and reviews. Date of last search: 29 March 2021. We included randomised or quasi-randomised controlled clinical studies, including cross-over studies, comparing ACBT with other airway clearance therapies in CF. Two review authors independently screened each article, abstracted data and assessed the risk of bias of each study. We used GRADE to assess our confidence in the evidence assessing quality of life, participant preference, adverse events, forced expiratory volume in one second (FEV1) % predicted, forced vital capacity (FVC) % predicted, sputum weight, and number of pulmonary exacerbations. Our search identified 99 studies, of which 22 (559 participants) met the inclusion criteria. Eight randomised controlled studies (259 participants) were included in the analysis; five were of cross-over design. The 14 remaining studies were cross-over studies with inadequate reports for complete assessment. The study size ranged from seven to 65 participants. The age of the participants ranged from six to 63 years (mean age 18.7 years). In 13 studies follow up lasted a single day. However, there were two long-term randomised controlled studies with follow up of one to three years. Most of the studies did not report on key quality items, and therefore, have an unclear risk of bias in terms of random sequence generation, allocation concealment, and outcome assessor blinding. Due to the nature of the intervention, none of the studies blinded participants or the personnel applying the interventions. However, most of the studies reported on all planned outcomes, had adequate follow up, assessed compliance, and used an intention-to-treat analysis. Included studies compared ACBT with autogenic drainage, airway oscillating devices (AOD), high-frequency chest compression devices, conventional chest physiotherapy (CCPT), positive expiratory pressure (PEP), and exercise. We found no difference in quality of life between ACBT and PEP mask therapy, AOD, other breathing techniques, or exercise (very low-certainty evidence). There was no difference in individual preference between ACBT and other breathing techniques (very low-certainty evidence). One study comparing ACBT with ACBT plus postural exercise reported no deaths and no adverse events (very low-certainty evidence). We found no differences in lung function (forced expiratory volume in one second (FEV1) % predicted and forced vital capacity (FVC) % predicted), oxygen saturation or expectorated sputum between ACBT and any other technique (very low-certainty evidence). There were no differences in the number of pulmonary exacerbations between people using ACBT and people using CCPT (low-certainty evidence) or ACBT with exercise (very low-certainty evidence), the only comparisons to report this outcome. There is little evidence to support or reject the use of the ACBT over any other airway clearance therapy and ACBT is comparable with other therapies in outcomes such as participant preference, quality of life, exercise tolerance, lung function, sputum weight, oxygen saturation, and number of pulmonary exacerbations. Longer-term studies are needed to more adequately assess the effects of ACBT on outcomes important for people with cystic fibrosis such as quality of life and preference.

Mucopenetrating Janus Nanoparticles For Field-Coverage Oral Cancer Chemoprevention

IntroductionOral squamous cell carcinoma (OSCC), is associated with high morbidity and mortality. Preemptive interventions have been postulated to provide superior therapeutic options, but their implementation has been restricted by the availability of broadly applicable local delivery systems.MethodsWe address this challenge by engineering a delivery vehicle, Janus nanoparticles (JNP), that combine the dual mucoadhesive properties of a first cationic chitosan compartment with a second hydrophobic poly(lactide-co-glycolide) release compartment. JNP are designed to avoid rapid mucus clearance while ensuring stable loading and controlled release of the IL-6 receptor antagonist, tocilizumab (TCZ).ResultsThe JNP featured defined and monodispersed sizes with an average diameter of 327 nm and a PDI of 0.245, high circularities above 0.90 and supported controlled release of TCZ and effective internalization by oral keratinocytes. TCZ released from JNP retained its biological activity and effectively reduced both, soluble and membrane-bound IL-6Rα (71% and 50%). In full-thickness oral mucosal explants, 76% of the JNP breached the stratum corneum and in 41% were observed in the basal cell layer indicating excellent mucopenetrating properties. When tested in an aggressive OSCC xenograft model, TCZ-loaded JNP showed high levels of xenograft inhibition and outperformed all control groups with respect to inhibition of tumor cell proliferation, reduction in tumor size and reduced expression of the proto-oncogene ERG.ConclusionBy combining critically required, yet orthogonal properties within the same nanoparticle design, the JNP in this study, demonstrate promise as precision delivery platforms for intraoral field-coverage chemoprevention, a vastly under-researched area of high clinical importance.

Bronchoscopy Findings of Severe and Critical COVID-19 Patients Treated in ICU: A Year of Experience in a Developing Country.

Bronchoscopy procedure in patients with COVID-19 poses significant challenges, especially in a developing country with limited resources. We aim to describe the clinical characteristics of severe and critical COVID-19 patients treated in an intensive care unit (ICU) and their bronchoscopy findings. We performed a retrospective analysis of clinical data of ICU patients with COVID-19 treated and received bronchoscopy procedures. This study retrospectively included all consecutive patients who underwent bronchoscopy at a teaching hospital in Depok, Indonesia, from May, 2020, until May, 2021. A total of 57 bronchoscopy procedures in 54 patients were performed in this study. Primary procedure indications were retained mucus (68.4%) and ventilatory support weaning failure (15.8%). Bronchoscopic findings were mostly hyperaemic mucosa (95.00%) and purulent secretion (50.90%). Microbiological findings from bronchoalveolar samples were Acinetobacter baumanii, Klebsiella pneumoniae, and Candida albicans (33.3%, 26.6%, and 10.5%, respectively). The most common fungal isolated were Candida albicans (28%), followed by Candida tropicalis (16%) and Aspergillus sp. (8%). The overall length of hospital stay was 24 days, and the in-ICU stay was 22.06 ± 10.99 days. The patients' survival of 28-days postprocedural outcome was 25.9% (14 subjects). Follow-up found that 20.4% of patients survived after sixty days of hospitalization. Diagnostic and therapeutic bronchoscopy in ICU patients with COVID-19 was safe and feasible to perform in developing countries with limited resources. It could help bronchial mucous clearance and confirm microbiological infection. The procedures should be strictly performed for patients with indications and comply with safety standards.

Complex wave’s impact on the cilia-generated flow in a vertical tube with an endoscope

ABSTRACT This research object is focused to discuss the cilia-driven flow along complex wave progression via cilia tips. Suspension of nanocomposites is considered in this analysis to discuss the enhanced heat transfer rate properties of the base fluid blood. The endoscopic tube is inserted into the flow region covered by cilia tips to overcome the cilia disorders. Governed mathematical equations are solved by the Mathematica DSolve command after using lubrication approximation. To see the theoretical consequence of complex cilia movement along the tube, graphical results are plotted for different innovative parameters which are discussed in detail. Streamlines are strategized to see the blood circulation pattern in the presence of the complex cilia waves. From a theoretical point of view, it is noted that complex cilia waves accelerate the fluid circulations more significantly near the ciliated walls. Moreover, the cilia-driven fluid flow has a substantial role in multiple progressions such as clearance of respiratory mucus, right-left pattern in the embryonic node, gamete transport in the oviduct, and cerebrospinal fluid flow.

Core-shell nanosystems designed for effective oral delivery of polypeptide drugs.

The stomach acid degradation, mucus clearance and intestinal epithelial impermeability severely limit the oral delivery of polypeptide drugs. To simultaneously address the three major barriers, novel self-assembled core-shell nanosystems (CA-NPs) were designed. The fabricated shell of citric acid cross-linked carboxymethyl cellulose (CA-CMC) wrapped on core nanoparticles (HA-NPs) maintained the integrity of CA-NPs in the stomach. When CA-NPs passed through the stomach, the CA-CMC shell was gradually degraded to release the core HA-NPs in the intestine. HA-NPs with numerous hydrophilic groups and mannose side chains rapidly penetrated through the mucus layer and efficiently transcellular transported via the glucose transporter (GLUT)-mediated and paracellular transport through reversible opening of tight junctions (TJs) by CA-CMC. The oral bioavailability and therapeutic effects of CA-NPs-loaded polypeptide colistin against Escherichia coli (E. coli) bacteremia in mice were significantly increased compared with the native colistin, respectively. Good safety was observed following oral daily delivery for 14 consecutive days. Thus, CA-NPs may offer a promising strategy for the oral delivery of polypeptide drugs.

MUC5B mobilizes and MUC5AC spatially aligns mucociliary transport on human airway epithelium.

Secreted mucus is a frontline defense against respiratory infection, enabling the capture and swift removal of infectious or irritating agents from the lungs. Airway mucus is composed of two mucins: mucin 5B (MUC5B) and 5AC (MUC5AC). Together, they form a hydrogel that can be actively transported by cilia along the airway surface. In chronic respiratory diseases, abnormal expression of these mucins is directly implicated in dysfunctional mucus clearance. Yet, the role of each mucin in supporting normal mucus transport remains unclear. Here, we generate human airway epithelial tissue cultures deficient in either MUC5B or MUC5AC to understand their individual contributions to mucus transport. We find that MUC5B and MUC5AC deficiency results in impaired and discoordinated mucociliary transport, respectively, demonstrating the importance of each mucin to airway clearance.

Mucolytic and Antioxidant Properties of Carbocysteine as a Strategy in COVID-19 Therapy.

SARS-CoV-2 infection leads to a heterogenous spectrum of clinical conditions ranging from self-limiting upper airway infection to severe respiratory failure. Carbocysteine is a thioether mucolytic with antioxidant and anti-inflammatory activities. Carbocysteine has been shown to have anti-viral effects on human rhinovirus, RSV and the influenza virus as well as interfering with upper airway ciliary motility, the first site of SARS-CoV-2 infection, leading to more effective mucus clearance and potential containment of viral spread towards the lower airway. Positive effects, in terms of limiting superimposed bacterial infection and reducing oxidative stress, have also been documented in COPD patients. Accordingly, Carbocysteine should also be considered in both post-exposure prophylaxis and early-phase treatment of COVID-19 in combination with other agents (monoclonal antibodies, antivirals, non-steroidal anti-inflammatory agents, and inhaled corticosteroids). In this review, we explored the pharmacokinetic and pharmacodynamic aspects of Carbocysteine to delineate its potential therapeutic impact in patients with COVID-19.

The effect of N-acetylcysteine in patients with non-cystic fibrosis bronchiectasis (NINCFB): study protocol for a multicentre, double-blind, randomised, placebo-controlled trial

BackgroundN-acetylcysteine (NAC), which is specifically involved in airway mucus clearance and antioxidation, is recommended by the treatment guideline for non-cystic fibrosis bronchiectasis (NCFB). However, there is little clinical evidence of its long-term efficacy concerning quality of life (QoL) and exacerbation in patients with NCFB. In addition, the influences of NAC on airway bacterial colonization, chronic inflammation and oxidative stress in NCFB are also unclear.MethodsNINCFB is a prospective, multicentre, double-blind, randomised, placebo-controlled trial that will recruit 119 patients with NCFB and randomly divide them into an NAC group (n = 79) and a control group (n = 40). Participants in the NAC group will receive 600 mg oral NAC twice daily for 52 weeks, while patients in the control group will receive 600 mg placebo twice daily for 52 weeks. The information at baseline will be collected once participants are enrolled. The primary endpoints are the changes in St George’s Respiratory Questionnaire scores and the number of exacerbations in 52 weeks. The secondary endpoints are the 16S rRNA of sputum and the levels of inflammatory factors and oxidative stressors in sputum and serum. Other data related to radiography, lung function tests, number of oral and/or intravenous antibiotic therapies and adverse events (AEs) will also be analysed. Further subgroup analysis distinguished by the severity of disease, severity of lung function, airway bacterial colonization and exacerbation frequency will be performed.DiscussionThe objective of this study is to determine the long-term efficacy of NAC on QoL and exacerbation of NCFB and to explore the effectiveness of NAC for antibiosis, anti-inflammation and antioxidation in NCFB. The study results will provide high-quality clinical proof for the revision and optimization of treatment guidelines and for expert consensus on NCFB treatment.Trial registrationThe trial was registered on the Chinese Clinical Trial Register at April 11, 2020 (chictr.org.cn, ChiCTR2000031817).

404 Why are mucins so gigantic, and is it rational to sever them to aid mucus clearance?

404 Why are mucins so gigantic, and is it rational to sever them to aid mucus clearance?

Preclinical evaluation of the epithelial sodium channel inhibitor AZD5634 and implications on human translation.

Airway dehydration causes mucus stasis and bacterial overgrowth in cystic fibrosis (CF), resulting in recurrent respiratory infections and exacerbations. Strategies to rehydrate airway mucus including inhibition of the epithelial sodium channel (ENaC) have the potential to improve mucosal defense by enhancing mucociliary clearance (MCC) and reducing the risk of progressive decline in lung function. In the current work, we evaluated the effects of AZD5634, an ENaC inhibitor that shows extended lung retention and safety profile as compared with previously evaluated candidate drugs, in healthy and CF preclinical model systems. We found that AZD5634 elicited a potent inhibition of amiloride-sensitive current in non-CF airway cells and airway cells derived from F508del-homozygous individuals with CF that effectively increased airway surface liquid volume and improved mucociliary transport (MCT) rate. AZD5634 also demonstrated efficacious inhibition of ENaC in sheep bronchial epithelial cells, translating to dose-dependent improvement of mucus clearance in healthy sheep in vivo. Conversely, nebulization of AZD5634 did not notably improve airway hydration or MCT in CF rats that exhibit an MCC defect, consistent with findings from a first single-dose evaluation of AZD5634 on MCC in people with CF. Overall, these findings suggest that CF animal models demonstrating impaired mucus clearance translatable to the human situation may help to successfully predict and promote the successful translation of ENaC-directed therapies to the clinic.

Expert consensus on the application of inhalation therapy in pulmonary rehabilitation in China

As an important component of disease management, pulmonary rehabilitation delays disease progression, alleviates symptoms, improves exercise tolerance and quality of life (QOL) in patients with chronic respiratory diseases (CRDs) and other types of respiratory dysfunction. Due to the disease characteristics of patients with respiratory dysfunction, patients generally have problems such as reduced exercise tolerance and impaired airway mucus clearance capability during pulmonary rehabilitation. Inhalation therapy has a unique and significant role in the treatment of respiratory diseases, complementing and promoting each other with pulmonary rehabilitation. Rational application of inhalation therapy can effectively prevent and treat the loss of exercise tolerance and improve the effect of airway clearance in pulmonary rehabilitation,while pulmonary rehabilitation techniques can help to improve the strength of inspiratory muscles, patient self-management, and improve the safety and effectiveness of inhalation therapy. However, there are still difficulties in clinical application due to different knowledge systems of clinical medicine and rehabilitation medicine. In order to further promote the discipline integration and better guide clinical practice,the Respiratory Branch of the Chinese Geriatrics Society (CGS) and the China Rehabilitation Hospital Association (CRHA) organized respiratory and rehabilitation experts to jointly formulate the Chinese expert consensus on the application of inhalation therapy in pulmonary rehabilitation.

Short-acting inhaled bronchodilators for cystic fibrosis.

Short-acting inhaled bronchodilators for cystic fibrosis.

Beneficial short-term effect of autogenic drainage on peripheral resistance in childhood cystic fibrosis disease

BackgroundAirway clearance techniques are supposed to be a necessary adjunct for the enhancement of impaired peripheral clearance in cystic fibrosis (CF). The objective was to assess the effect of one physiotherapy session (autogenic drainage: AD) on mucus clearance (sputum wet weight) and impulse oscillometry system (IOS) indices, including those obtained from extended Resistance-Inertance-Compliance (eRIC) modelling, considering the degree of bronchial congestion.MethodsThirty children with CF (median age: 12.7 years) in a stable condition prospectively underwent IOS measurements at baseline and after AD. They were divided in two groups: with (visual analog scale of bronchial congestion by the physiotherapist ≥ 5/10) and without (scale < 5/10) bronchial congestion. Paired-comparison of the effects of AD on airway resistance measurements was done with Wilcoxon test.ResultsThe congestion scale correlated with the wet weight of sputum production during the session (Pearson test: p < 0.0001, R = 0.66). Ten children had bronchial congestion and 20 were without congestion. In the whole group, R5–20 Hz significantly decreased after AD (P = 0.049), which was related to a decrease in the children with congestion (P = 0.025), whereas it was not significantly modified in the children without congestion (P = 0.327). The eRIC model allowed the calculation of the peripheral resistance of the respiratory system, which also decreased in the children with congestion (P = 0.037), however, not modified in the children without congestion (P = 0.390).ConclusionOne session of autogenic drainage has the ability to decrease peripheral resistance obtained from IOS measurements, more specifically in children with CF with moderate to severe bronchial congestion.Trial registrationClinicalTrials.gov Identifier: NCT04094441.

Pulsated Herschel-Bulkley flows in two-dimensional channels: A model for mucus clearance devices

Mucus is a complex biological fluid covering the human respiratory tract and protecting the bronchial epithelium from fine particles and pathogens. In pathological conditions, it typically tends to dehydrate, becoming viscous, sticky and difficult to evacuate by natural mechanisms. Various devices to aid in the clearance of airways based on the use of pressure waves are being developed, and in that context there is a strong need to better understand the interactions between mucus and oscillating pressure waves. This paper investigates the interactions between a yield stress shear-thinning/thickening fluid and different types of pressure waves in a two-dimensional channel.

Effect of airway clearance therapies on mucociliary clearance in adults with cystic fibrosis: A randomized controlled trial.

Cystic fibrosis (CF) is an inherited disorder causing impaired mucociliary clearance within the respiratory tract, and is associated with bronchiectasis, chronic respiratory infections, and early death. Airway clearance therapies have long been a cornerstone of management of individuals with CF, although evidence supporting their use is lacking. We designed a randomized controlled trial to quantitatively compare the effects of different forms of airway clearance on mucociliary clearance. Three different physiotherapy methods to augment cough-clearance were studied in addition to cough-clearance alone: high-frequency chest-wall oscillating vest, oscillatory positive expiratory pressure, and whole-body vibration. We used gamma scintigraphy after inhalation of radiolabeled particles to quantify mucus clearance before, during, and after physiotherapy. As secondary endpoints, we measured concentrations of small molecules in exhaled breath that may impact mucus clearance. Ten subjects were enrolled and completed study procedures. No differences were identified between any method of airway clearance, including cough clearance alone. We did identify changes in certain small molecule concentrations in exhaled breath following airway clearance. Due to the limitations of this study, we do not believe the negative results suggest a change in clinical practice with regard to airway clearance. Findings pertaining to small molecules in exhaled breath may serve as future opportunities for study.