The direct effect of hyperosmolar agents on ciliary beating of human bronchial epithelial cells

Exploring the appropriate dose of nebulized hypertonic saline for bronchiolitis: a dose-response meta-analysis

Nebulized hypertonic saline (HS) has gathered increasing attention in bronchiolitis. This study aims to evaluate the relationship between the dose of nebulized HS and the effects on bronchiolitis. Five electronic databases-PubMed, EMBASE, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, and ISRCTN-were searched until May 2021. Randomized controlled trials (RCTs) that investigated the effect of HS on bronchiolitis were included. A total of 35 RCTs met the eligibility criteria. HS nebulization may shorten the length of stay (LOS) in hospital (mean difference -0.47, 95% CI -0.71 to -0.23) and improve the 24-hour, 48-hour, and 72-hour Clinical Severe Score (CSS) in children with bronchiolitis. The results showed that there was no significant difference between 3% HS and the higher doses (>3%) of HS in LOS and 24-hour CSS. Although the dose-response meta-analysis found that there may be a linear relationship between different doses and effects, the slope of the linear model changed with different included studies. Besides, HS nebulization could reduce the rate of hospitalization of children with bronchiolitis (risk ratio 0.88, 95% CI 0.78 to 0.98), while the trial sequential analysis indicated the evidence may be insufficient and potentially false positive. This study showed that nebulized HS is an effective and safe therapy for bronchiolitis. More studies are necessary to be conducted to evaluate the effects of different doses of HS on bronchiolitis.

Rapid changes in mucociliary transport in the tracheal epithelium caused by unconditioned room air or nebulized hypertonic saline and mannitol are not determined by frequency of beating cilia

Background

Inspired air is heated and humidified in the nose before it reaches lower airways. This mechanism is bypassed during tracheostomy, directly exposing the airways to colder and drier air from the environment, known to negatively affect mucociliary transport; however, little is known about how quickly mucociliary transport deteriorates. This study determines the short-term effect of flowing room air and nebulized hypertonic saline and mannitol on mucociliary transport in the trachea. In an ovine perfused in vitro tracheal model (N = 9) the epithelium was exposed to 25 L/min of flow, heated to lamb body temperature (38 °C) and fully saturated with water vapor as the control, followed by either room air (22 °C and 50% relative humidity) or nebulized solutions of NaCl 7% and mannitol 20% up to 1 min for a short duration, until mucociliary transport had visually changed. Mucus transport velocity (MTV) and cilia beat frequency (CBF) were continuously measured with video-microscopy.

Results

Exposing the tracheal epithelium to air heated to body temperature and fully humidified had stable MTV 9.5 ± 1.1 mm/min and CBF 13.4 ± 0.6 Hz. When exposed to flow of room air, MTV slowed down to 0.1 ± 0.1 mm/min in 2.0 ± 0.4 s followed by a decrease in CBF to 6.7 ± 1.9 Hz, after 2.3 ± 0.8 s. Both MTV and CBF recovered to their initial state when heated and humidified air-flow was re-introduced. Exposing the tracheal epithelium to nebulized hypertonic saline and nebulized mannitol for 1 min increased MTV without a subsequent increase in CBF.

Conclusions

This study demonstrates mucociliary transport can deteriorate within seconds of exposing the tracheal epithelium to flowing room air and increase rapidly when exposed to nebulized hypertonic solutions. The reduction in MTV precedes slowing of CBF with room air and MTV increases without a subsequent increase in CBF during the nebulization. Their relationship is non-linear and a minimum CBF of approximately 6 Hz is required for MTV > 0, while MTV can reach 10.9 mm/min without CBF increasing. Clinically these findings indicate a potential rapid detrimental effect of breathing with non-humidified air via bypassed upper airways and the short-term effects of nebulized osmotic agents that increase MTV.

Ciliary functional analysis: Beating a path towards standardization

Primary ciliary dyskinesia is an inherited disorder in which respiratory cilia are stationary, or beat in a slow or dyskinetic manner, leading to impaired mucociliary clearance and significant sinopulmonary disease. One diagnostic test is ciliary functional analysis using digital high-speed video microscopy (DHSV), which allows real-time analysis of complete ciliary function, comprising ciliary beat frequency (CBF) and ciliary beat pattern (CBP). However, DHSV lacks standardization. In this paper, the current knowledge of DHSV ciliary functional analysis is presented, and recommendations given for a standardized protocol for ciliary sample collection and processing. A proposal is presented for a quantitative and qualitative CBP evaluation system, to be used to develop international consensus agreement, and future DHSV research areas are identified.

Transcriptomic response of primary human airway epithelial cells to flavoring chemicals in electronic cigarettes

The widespread use of electronic cigarettes (e-cigarettes or e-cig) is a growing public health concern. Diacetyl and its chemical cousin 2,3-pentanedione are commonly used to add flavors to e-cig; however, little is known about how the flavoring chemicals may impair lung function. Here we report that the flavoring chemicals induce transcriptomic changes and perturb cilia function in the airway epithelium. Using RNA-Seq, we identified a total of 163 and 568 differentially expressed genes in primary normal human bronchial epithelial (NHBE) cells that were exposed to diacetyl and 2,3-pentanedione, respectively. DAVID pathway analysis revealed an enrichment of cellular pathways involved in cytoskeletal and cilia processes among the set of common genes (142 genes) perturbed by both diacetyl and 2,3-pentanedione. Consistent with this, qRT-PCR confirmed that the expression of multiple genes involved in cilia biogenesis was significantly downregulated by diacetyl and 2,3-pentanedione in NHBE cells. Furthermore, immunofluorescence staining showed that the number of ciliated cells was significantly decreased by the flavoring chemicals. Our study indicates that the two widely used e-cig flavoring chemicals impair the cilia function in airway epithelium and likely contribute to the adverse effects of e-cig in the lung.

Airway Epithelial Cell Cilia and Obstructive Lung Disease

Airway epithelium is the first line of defense against exposure of the airway and lung to various inflammatory stimuli. Ciliary beating of airway epithelial cells constitutes an important part of the mucociliary transport apparatus. To be effective in transporting secretions out of the lung, the mucociliary transport apparatus must exhibit a cohesive beating of all ciliated epithelial cells that line the upper and lower respiratory tract. Cilia function can be modulated by exposures to endogenous and exogenous factors and by the viscosity of the mucus lining the epithelium. Cilia function is impaired in lung diseases such as COPD and asthma, and pharmacologic agents can modulate cilia function and mucus viscosity. Cilia beating is reduced in COPD, however, more research is needed to determine the structural-functional regulation of ciliary beating via all signaling pathways and how this might relate to the initiation or progression of obstructive lung diseases. Additionally, genotypes and how these can influence phenotypes and epithelial cell cilia function and structure should be taken into consideration in future investigations.

The effect of drugs and other compounds on the ciliary beat frequency of human respiratory epithelium

BACKGROUND

Cilia in the human respiratory tract play a critical role in clearing mucus and debris from the airways. Their function can be affected by a number of drugs or other substances, many of which alter ciliary beat frequency (CBF). This has implications for diseases of the respiratory tract and nasal drug delivery. This article is a systematic review of the literature that examines 229 substances and their effect on CBF.

METHODS

MEDLINE was the primary database used for data collection. Eligibility criteria based on experimental design were established, and 152 studies were ultimately selected. Each individual trial for the substances tested was noted whenever possible, including concentration, time course, specific effect on CBF, and source of tissue.

RESULTS

There was a high degree of heterogeneity between the various experiments examined in this article. Substances and their general effects (increase, no effect, decrease) were grouped into six categories: antimicrobials and antivirals, pharmacologics, human biological products, organisms and toxins, drug excipients, and natural compounds/other manipulations.

CONCLUSION

Organisms, toxins, and drug excipients tend to show a cilioinhibitory effect, whereas substances in all other categories had mixed effects. All studies examined were in vitro experiments, and application of the results in vivo is confounded by several factors. The data presented in this article should be useful in future respiratory research and examination of compounds for therapeutic and drug delivery purposes.

Duration of action of hypertonic saline on mucociliary clearance in the normal lung

Inhalation of hypertonic saline (HS) acutely enhances mucociliary clearance (MC) in both health and disease. In patients with cystic fibrosis (CF), repeated use of HS causes a sustained improvement in MC as well as clinical benefit. The pharmacodynamic duration of activity on MC may be an important determinant of its therapeutic potential in other airways diseases. Before moving toward testing the clinical benefits of HS for non-CF indications, we sought to assess the duration of pharmacodynamic effects of HS in healthy subjects by performing radiotracer clearance studies at baseline, 30-min post-HS administration, and 4-h post-HS administration. Indeed, acceleration of MC was observed when measured 30 min after HS inhalation. This acceleration was most pronounced in the first 30 min after inhaling the radiotracer in the central lung region (mean Ave30Clr = 15.5 vs. 8.6% for 30-min post-HS treatment vs. mean baseline, respectively, P < 0.005), suggesting that acute HS effects were greatest in the larger bronchial airways. In contrast, when MC was measured 4 h after HS administration, all indices of central lung region MC were slower than at baseline: Ave30Clr = 5.9% vs. 8.6% (P = 0.10); Ave90Clr = 12.4% vs. 16.8% (P < 0.05); clearance through 3 h = 29.4 vs. 43.7% (P < 0.002); and clearance through 6 h = 39.4 vs. 50.2% (P < 0.02). This apparent slowing of MC in healthy subjects 4-h post-HS administration may reflect depletion of airway mucus following acute HS administration.

Efficacy and adverse effects of drugs used to treat adult cystic fibrosis

INTRODUCTION

Cystic fibrosis (CF) is an autosomal recessive disease and is the most commonly seen monogenetic disease in Caucasians. The disease has various manifestations resulting from the abnormal thick secretions, most common being chronic lung infection and airway obstruction. Many new promising drugs have appeared on the horizon over the years. This review here is an attempt to bring together the various treatments being used to prolong and enhance the quality of life of CF patients.

AREAS COVERED

A literature review of published as well as ongoing clinical trials, meta-analysis and systematic reviews regarding the drugs used in CF management was carried out using PubMed and Ovid databases.

EXPERT OPINION

New concepts have been formed and some positive results in this direction have already led to the approval of cystic fibrosis transmembrane conductance regulator potentiator drug. Gene therapy and stem cell therapy are under development. The current therapies such as dornase alfa and pancreatic enzymes targeting the symptoms continue to evolve as they play an important complementary role. Development of new simple and cost-effective markers, which help assess the efficacy and safety of these constantly emerging new drugs, is also being investigated.

Genetics, diagnosis, and future treatment strategies for primary ciliary dyskinesia

INTRODUCTION

Primary ciliary dyskinesia (PCD) is a genetically heterogeneous recessive disorder resulting in chronic oto-sino-pulmonary disease. While PCD is estimated to occur in 1 in 20,000 individuals, fewer than 1,000 patients in the US have a well-established diagnosis.

AREAS COVERED

We provide an overview of the clinical manifestations of PCD, describe the evolution of diagnostic methods, and critique the literature on management of PCD.

EXPERT OPINION

Although interest in clinical studies in non-CF bronchiectasis has increased in recent years, some of whom enroll patients with PCD, the literature regarding therapy for PCD as a distinct entity is lacking, as the numbers are small, and there have been no sub-analyses published. However, with improved screening and diagnostic methods, the development of clinical and research consortiums, and actively enrolling registries of PCD patients, the environment is conducive to perform longitudinal studies of disease course and therapeutic studies to alter that course.

Combined inhaled salbutamol and mannitol therapy for mucus hyper-secretion in pulmonary diseases

This study focuses on the co-engineering of salbutamol sulphate (SS), a common bronchodilator, and mannitol (MA), a mucolytic, as a potential combination therapy for mucus hypersecretion. This combination was chosen to have a synergic effect on the airways: the SS will act on the β2-receptor for relaxation of smooth muscle and enhancement of ciliary beat frequency, whilst mannitol will improve the fluidity of mucus, consequently enhancing its clearance from the lung. A series of co-spray-dried samples, containing therapeutically relevant doses of SS and MA, were prepared. The physico-chemical characteristics of the formulations were evaluated in terms of size distribution, morphology, thermal and moisture response and aerosol performance. Additionally, the formulations were evaluated for their effects on cell viability and transport across air interface Calu-3 bronchial epithelial cells, contractibility effects on bronchial smooth muscle cells and cilia beat activity using ciliated nasal epithelial cells in vitro. The formulations demonstrated size distributions and aerosol performance suitable for inhalation therapy. Transport studies revealed that the MA component of the formulation enhanced penetration of SS across the complex mucus layer and the lung epithelia cells. Furthermore, the formulation in the ratios of SS 10(-6) and MA 10(-3) M gave a significant increase in cilia beat frequency whilst simultaneously preventing smooth muscle contraction associated with mannitol administration. These studies have established that co-spray dried combination formulations of MA and SS can be successfully prepared with limited toxicity, good aerosol performance and the ability to increase ciliary beat frequency for improving the mucociliary clearance in patients suffering from hyper-secretory diseases, whilst simultaneously acting on the underlying smooth muscle.

Effect of inhaled dry powder mannitol on mucus and its clearance

Insufficient hydration at the airway surface can make mucus adherent and poorly cleared. Cough, the major mechanism of mucus clearance in disease, is ineffective when mucus is adhesive. Inhaled mannitol creates an osmotic drive for water to move into the airway lumen. The consequent increased hydration of the airway surface decreases the adherence of mucus to the epithelium, facilitates the coupling of mucus and cilia thereby increasing mucus clearance. Inhaled mannitol also promotes effective coughing and stimulates mucociliary clearance. The beneficial effect of mannitol on mucus and its clearance has been demonstrated in patients with asthma, bronchiectasis and cystic fibrosis. Inhaled dry powder mannitol (Bronchitol™) is promising to be an effective treatment for the clearance of retained airway secretions.

Treatment for sulfur mustard lung injuries; new therapeutic approaches from acute to chronic phase

Objective

Sulfur mustard (SM) is one of the major potent chemical warfare and attractive weapons for terrorists. It has caused deaths to hundreds of thousands of victims in World War I and more recently during the Iran-Iraq war (1980–1988). It has ability to develop severe acute and chronic damage to the respiratory tract, eyes and skin. Understanding the acute and chronic biologic consequences of SM exposure may be quite essential for developing efficient prophylactic/therapeutic measures. One of the systems majorly affected by SM is the respiratory tract that numerous clinical studies have detailed processes of injury, diagnosis and treatments of lung. The low mortality rate has been contributed to high prevalence of victims and high lifetime morbidity burden. However, there are no curative modalities available in such patients. In this review, we collected and discussed the related articles on the preventive and therapeutic approaches to SM-induced respiratory injury and summarized what is currently known about the management and therapeutic strategies of acute and long-term consequences of SM lung injuries.

Method

This review was done by reviewing all papers found by searching following key words sulfur mustard; lung; chronic; acute; COPD; treatment.

Results

Mustard lung has an ongoing pathological process and is active disorder even years after exposure to SM. Different drug classes have been studied, nevertheless there are no curative modalities for mustard lung.

Conclusion

Complementary studies on one hand regarding pharmacokinetic of drugs and molecular investigations are mandatory to obtain more effective treatments.