Mucociliary and long-term particle clearance in airways of patients with immotile cilia

Hypoxia-induced cystic fibrosis transmembrane conductance regulator dysfunction is a universal mechanism underlying reduced mucociliary transport in sinusitis

INTRODUCTION

Hypoxia due to sinus obstruction is a major pathogenic mechanism leading to sinusitis. The objective of the current study is to define the electrophysiologic characteristics of hypoxia in vitro and in vivo.

METHODS

Cystic fibrosis bronchoepithelial cells expressing wild-type cystic fibrosis transmembrane conductance regulator (CFTR) and human sinonasal epithelial cells were exposed to 1% or atmospheric O2 for 24 h. Time-dependent production of cytoplasmic free radicals was measured. Cells were subjected to Ussing chamber and patch clamp technique where CFTR currents were recorded in whole-cell and cell-attached mode for single channel studies. Indices of mucociliary transport (MCT) were measured using micro-optical coherence tomography. In a rabbit hypoxic maxillary sinus model, tissue oxygenation, relative mRNA expression of HIF-1α, pH, sinus potential difference (SPD), and MCT were determined.

RESULTS

Ussing chamber (p < 0.05), whole-cell (p < 0.001), and single channel patch-clamp (p < 0.0001) showed significant inhibition of Cl- currents in hypoxic cells. Cytoplasmic free radicals showed time-dependent elevation peaking at 4 h (p < 0.0001). Airway surface liquid (p < 0.0001), periciliary liquid (p < 0.001), and MCT (p < 0.01) were diminished. Co-incubation with the free radical scavenger glutathione negated the impact of hypoxia on single channel currents and MCT markers. In sinusitis rabbits, mucosa exhibited low tissue oxygenation (p < 0.0001), increased HIF1α mRNA (p < 0.05), reduced pH (p < 0.01), and decreased MCT (p < 0.001). SPD measurements demonstrated markedly diminished transepithelial Cl- transport (p < 0.0001).

CONCLUSION

Hypoxia induces severe CFTR dysfunction via free radical production causing reduced MCT in vitro and in vivo. Improved oxygenation is critical to reducing the impact of persistent mucociliary dysfunction.

Aerosolization of poly(sulfobetaine) microparticles that encapsulate therapeutic antibodies

Pulmonary delivery of protein therapeutics poses significant challenges that have not been well addressed in the research literature or practice. In fact, there is currently only one commercial protein therapeutic that is delivered through aerosolization and inhalation. In this study, we propose a drug delivery strategy that enables a high-concentration dosage for the pulmonary delivery of antibodies as an aerosolizable solid powder with desired stability. We utilized zwitterionic polymers for their promising properties as drug delivery vehicles and synthesized swellable, biodegradable poly(sulfo-betaine) (pSB) microparticles. The microparticles were loaded with Immunoglobulin G (IgG) as a model antibody. We quantified the microparticle size and morphology, and the particles were found to have an average diameter of 1.6 μm, falling within the optimal range (~1-5 μm) for pulmonary drug delivery. In addition, we quantified the impact of the crosslinker to monomer ratio on particle morphology and drug loading capacity. The results showed that there is a trade-off between desired morphology and drug loading capacity as the crosslinker density increases. In addition, the particles were aerosolized, and our data indicated that the particles remained intact and retained their initial morphology and size after aerosolization. The combination of morphology, particle size, antibody loading capacity, low cytotoxicity, and ease of aerosolization support the potential use of these particles for pulmonary delivery of protein therapeutics.

Climate change, air quality, and respiratory health: a focus on particle deposition in the lungs

This review article delves into the multifaceted relationship between climate change, air quality, and respiratory health, placing a special focus on the process of particle deposition in the lungs. We discuss the capability of climate change to intensify air pollution and alter particulate matter physicochemical properties such as size, dispersion, and chemical composition. These alterations play a significant role in influencing the deposition of particles in the lungs, leading to consequential respiratory health effects. The review paper provides a broad exploration of climate change's direct and indirect role in modifying particulate air pollution features and its interaction with other air pollutants, which may change the ability of particle deposition in the lungs. In conclusion, climate change may play an important role in regulating particle deposition in the lungs by changing physicochemistry of particulate air pollution, therefore, increasing the risk of respiratory disease development.

Gene Therapy for Immunoglobulin E, Complement-Mediated, and Eosinophilic Disorders

Immunoglobulin E, complement, and eosinophils play an important role in host defense, but dysfunction of each of these components can lead to a variety of human disorders. In this review, we summarize how investigators have adapted gene therapy and antisense technology to modulate immunoglobulin E, complement, and/or eosinophil levels to treat these disorders.

Alcohol-Induced Mucociliary Dysfunction: Role of Defective CFTR Channel Function

Excessive alcohol use is thought to increase the risk of respiratory infections by impairing mucociliary clearance (MCC). In this study, we investigate the hypothesis that alcohol reduces the function of CFTR, the protein that is defective in individuals with cystic fibrosis, thus altering mucus properties to impair MCC and the airway's defense against inhaled pathogens.

Methods

Sprague Dawley rats with wild type CFTR (+/+), matched for age and sex, were administered either a Lieber-DeCarli alcohol diet or a control diet with the same number of calories for eight weeks. CFTR activity was measured using nasal potential difference (NPD) assay and Ussing chamber electrophysiology of tracheal tissue samples. In vivo MCC was determined by measuring the radiographic clearance of inhaled Tc99 particles and the depth of the airway periciliary liquid (PCL) and mucus transport rate in excised trachea using micro-optical coherence tomography (μOCT). The levels of rat lung MUC5b and CFTR were estimated by protein and mRNA analysis.

Results

Alcohol diet was found to decrease CFTR ion transport in the nasal and tracheal epithelium in vivo and ex vivo. This decrease in activity was also reflected in partially reduced full-length CFTR protein levels but not, in mRNA copies, in the lungs of rats. Furthermore, alcohol-fed rats showed a significant decrease in MCC after 8 weeks of alcohol consumption. The trachea from these rats also showed reduced PCL depth, indicating a decrease in mucosal surface hydration that was reflected in delayed mucus transport. Diminished MCC rate was also likely due to the elevated MUC5b expression in alcohol-fed rat lungs.

Conclusions

Excessive alcohol use can decrease the expression and activity of CFTR channels, leading to reduced airway surface hydration and impaired mucus clearance. This suggests that CFTR dysfunction plays a role in the compromised lung defense against respiratory pathogens in individuals who drink alcohol excessively.

Primary Ciliary Dyskinesia: A Rare and Often Underdiagnosed Disease

Primary ciliary dyskinesia (PCD) is a rare autosomal recessive disease with clinical features of ear, sinus, and pulmonary infections that overlap with common respiratory illnesses of childhood. It is a progressive disorder that has significant influence on quality of life, lung function, and survival. Given the considerable overlap of symptoms between common illnesses and PCD, a high index of suspicion by primary care providers is needed to consider the diagnosis. There is not a single "gold standard" diagnostic test for PCD and multiple diagnostic methods coupled with specialized expertise is often needed to make the diagnosis. Patients with PCD also have comorbidities requiring a multidisciplinary approach for optimal clinical management. It is important for primary care physicians to recognize the PCD clinical phenotype and have a diagnostic framework for these patients. [Pediatr Ann. 2022;51(2):e82-e85.].

Extracellular matrix-inspired inhalable aerogels for rapid clearance of pulmonary tuberculosis

Tuberculosis (TB) remains a leading cause of death from a single infectious agent, and limiting the spread of multidrug-resistant TB (MDR-TB) is now an urgent global health priority. Essential to the persistence of this disease is the ability of Mycobacterium tuberculosis (Mtb) to circumvent host defenses by infecting lung macrophages to create a cellular niche for its survival and proliferation. This has urged the development of new therapeutic strategies that act through mechanisms distinct from conventional antibiotics, and thus are effective against MDR bacteria, while being able to efficiently kill persister Mtb cells in infected host macrophages. Here, we report a new class of gel-like microparticle aerosols, or 'aerogels', designed to exploit metabolic vulnerabilities of Mtb pathogens and TB-infected macrophages to enable preferential delivery of synergistic peptide-antibiotic combinations for potent and rapid antitubercular therapy. This is achieved by formulating aerogels through the supramolecular assembly of a de novo designed anti-TB peptide and the extracellular matrix (ECM)-derived polysaccharide, hyaluronic acid (HA). Importantly, HA serves as a nutrient source for Mtb cells during tissue invasion and proliferation, and is recognized by CD44 receptors highly expressed on lung macrophages during TB infection. By exploiting this metabolic substrate for pathogen targeting, HA aerogels are shown to avidly bind and kill both drug-sensitive and drug-resistant mycobacteria, while being efficiently internalized into macrophage host cells in vitro and in vivo to clear Mtb persisters. This multifaceted bioactivity suggests aerogels may serve as a versatile inhalable platform upon which novel biomaterials-enabled therapeutics can be developed to rapidly clear pulmonary MDR-TB.

Ultrafine particles altered gut microbial population and metabolic profiles in a sex-specific manner in an obese mouse model

Emerging evidence has highlighted the connection between exposure to air pollution and the increased risk of obesity, metabolic syndrome, and comorbidities. Given the recent interest in studying the effects of ultrafine particle (UFP) on the health of obese individuals, this study examined the effects of gastrointestinal UFP exposure on gut microbial composition and metabolic function using an in vivo murine model of obesity in both sexes. UFPs generated from light-duty diesel engine combustion of petrodiesel (B0) and a petrodiesel/biodiesel fuel blend (80:20 v/v, B20) were administered orally. Multi-omics approaches, including liquid chromatography-mass spectrometry (LC-MS) based targeted metabolomics and 16S rRNA gene sequence analysis, semi-quantitatively compared the effects of 10-day UFP exposures on obese C57B6 mouse gut microbial population, changes in diversity and community function compared to a phosphate buffer solution (PBS) control group. Our results show that sex-specific differences in the gut microbial population in response to UFP exposure can be observed, as UFPs appear to have a differential impact on several bacterial families in males and females. Meanwhile, the alteration of seventy-five metabolites from the gut microbial metabolome varied significantly (ANOVA p < 0.05) across the PBS control, B0, and B20 groups. Multivariate analyses revealed that the fuel-type specific disruption to the microbial metabolome was observed in both sexes, with stronger disruptive effects found in females in comparison to male obese mice. Metabolic signatures of bacterial cellular oxidative stress, such as the decreased concentration of nucleotides and lipids and increased concentrations of carbohydrate, energy, and vitamin metabolites were detected. Furthermore, blood metabolites from the obese mice were differentially affected by the fuel types used to generate the UFPs (B0 vs. B20).

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.

Mucociliary Respiratory Epithelium Integrity in Molecular Defense and Susceptibility to Pulmonary Viral Infections

Mucociliary defense, mediated by the ciliated and goblet cells, is fundamental to respiratory fitness. The concerted action of ciliary movement on the respiratory epithelial surface and the pathogen entrapment function of mucus help to maintain healthy airways. Consequently, genetic or acquired defects in lung defense elicit respiratory diseases and secondary microbial infections that inflict damage on pulmonary function and may even be fatal. Individuals living with chronic and acute respiratory diseases are more susceptible to develop severe coronavirus disease-19 (COVID-19) illness and hence should be proficiently managed. In light of the prevailing pandemic, we review the current understanding of the respiratory system and its molecular components with a major focus on the pathophysiology arising due to collapsed respiratory epithelium integrity such as abnormal ciliary movement, cilia loss and dysfunction, ciliated cell destruction, and changes in mucus rheology. The review includes protein interaction networks of coronavirus infection-manifested implications on the molecular machinery that regulates mucociliary clearance. We also provide an insight into the alteration of the transcriptional networks of genes in the nasopharynx associated with the mucociliary clearance apparatus in humans upon infection by severe acute respiratory syndrome coronavirus-2.

Application of green tea catechins, polysaccharides, and flavonol prevent fine dust induced bronchial damage by modulating inflammation and airway cilia

Airborne fine dust particles (FDPs) have been identified as major toxins in air pollution that threaten human respiratory health. While searching for an anti-FDP reagent, we found that green tea extract (GTE) and fractions rich in flavonol glycosides (FLGs) and crude tea polysaccharides (CTPs) had protective effects against FDP-stimulated cellular damage in the BEAS-2B airway epithelial cell line. The GTE, FLGs, and CTPs significantly increased viability and lowered oxidative stress levels in FDP-treated cells. Combined treatment with GTE, FLGs, and CTPs also exerted synergistic protective effects on cells and attenuated FDP-induced elevations in inflammatory gene expression. Moreover, the green tea components increased the proportion of ciliated cells and upregulated ciliogenesis in the airway in FDP-stimulated BEAS-2B cells. Our findings provide insights into how natural phytochemicals protect the airway and suggest that green tea could be used to reduce FDP-induced airway damage as an ingredient in pharmaceutical, nutraceutical, and also cosmeceutical products.

Airway Hygiene in Children and Adults for Lowering Respiratory Droplet Exposure in Clean and Dirty Air

Respiratory illness threatens the learning potential of hundreds of millions of children around the world. We find in a human volunteer study involving three sites and 253 volunteers that respiratory droplets — of the size and nature to potentially contain COVID-19, influenza, allergens and other contaminants — diminish in number on exhalation by up to 99% via the “airway hygiene” administration of a nasal saline rich in calcium. Exhaled particles were significantly higher and efficacy of airway hygiene greatest at the site (Bangalore India) with highest fine particle ambient air burden. We argue for the use of airway hygiene for pandemic and post-pandemic global learning.

An Embryonic Zebrafish Model to Screen Disruption of Gut-Vascular Barrier upon Exposure to Ambient Ultrafine Particles

Epidemiological studies have linked exposure to ambient particulate matter (PM) with gastrointestinal (GI) diseases. Ambient ultrafine particles (UFP) are the redox-active sub-fraction of PM2.5, harboring elemental and polycyclic aromatic hydrocarbons from urban environmental sources including diesel and gasoline exhausts. The gut-vascular barrier (GVB) regulates paracellular trafficking and systemic dissemination of ingested microbes and toxins. Here, we posit that acute UFP ingestion disrupts the integrity of the intestinal barrier by modulating intestinal Notch activation. Using zebrafish embryos, we performed micro-gavage with the fluorescein isothiocynate (FITC)-conjugated dextran (FD10, 10 kDa) to assess the disruption of GVB integrity upon UFP exposure. Following micro-gavage, FD10 retained in the embryonic GI system, migrated through the cloaca. Conversely, co-gavaging UFP increased transmigration of FD10 across the intestinal barrier, and FD10 fluorescence occurred in the venous capillary plexus. Ingestion of UFP further impaired the mid-intestine morphology. We performed micro-angiogram of FD10 to corroborate acute UFP-mediated disruption of GVB. Transient genetic and pharmacologic manipulations of global Notch activity suggested Notch regulation of the GVB. Overall, our integration of a genetically tractable embryonic zebrafish and micro-gavage technique provided epigenetic insights underlying ambient UFP ingestion disrupts the GVB.

Chronic rhinosinusitis: phenotypes and endotypes

PURPOSE OF REVIEW

Chronic rhinosinusitis (CRS) is a broad classification of airway inflammation that affects a significant portion of the population. The current model of delineating patients suffering from CRS is dated and is no longer as simple as the presence of polyps or no polyps. Continued advances in the endotype descriptions of CRS have allowed for new phenotypic descriptions that aid in driving management and research efforts.

RECENT FINDINGS

Geographic differences exist between patient presentations, which require a molecular evaluation of the driving forces. Increased understanding of these differences allows for patient-specific treatment decisions.

SUMMARY

New descriptions of CRS phenotypes allow for more targeted therapy for patients, particularly to those with difficult to control disease. The previously broad classification of CRS with or without nasal polyps is no longer sufficient at driving these treatment decisions.

Update on Streptococcus suis Research and Prevention in the Era of Antimicrobial Restriction: 4th International Workshop on S. suis

Streptococcus suis is a swine pathogen and a zoonotic agent afflicting people in close contact with infected pigs or pork meat. Sporadic cases of human infections have been reported worldwide. In addition, S. suis outbreaks emerged in Asia, making this bacterium a primary health concern in this part of the globe. In pigs, S. suis disease results in decreased performance and increased mortality, which have a significant economic impact on swine production worldwide. Facing the new regulations in preventive use of antimicrobials in livestock and lack of effective vaccines, control of S. suis infections is worrisome. Increasing and sharing of knowledge on this pathogen is of utmost importance. As such, the pathogenesis and epidemiology of the infection, antimicrobial resistance, progress on diagnosis, prevention, and control were among the topics discussed during the 4th International Workshop on Streptococcus suis (held in Montreal, Canada, June 2019). This review gathers together recent findings on this important pathogen from lectures performed by lead researchers from several countries including Australia, Canada, France, Germany, Japan, Spain, Thailand, The Netherlands, UK, and USA. Finally, policies and recommendations for the manufacture, quality control, and use of inactivated autogenous vaccines are addressed to advance this important field in veterinary medicine.

Induction of systemic immunity through nasal-associated lymphoid tissue (NALT) of mice intranasally immunized with Brucella abortus malate dehydrogenase-loaded chitosan nanoparticles

Infection with Brucella abortus causes contagious zoonosis, brucellosis, and leads to abortion in animals and chronic illness in humans. Chitosan nanoparticles (CNs), biocompatible and nontoxic polymers, acts as a mucosal adjuvant. In our previous study, B. abortus malate dehydrogenase (Mdh) was loaded in CNs, and it induced high production of pro-inflammatory cytokines in THP-1 cells and systemic IgA in BALB/C mice. In this study, the time-series gene expression analysis of nasal-associated lymphoid tissue (NALT) was performed to identify the mechanism by which Mdh affect the target site of nasal immunization. We showed that intranasal immunization of CNs-Mdh reduced cell viability of epithelial cells and muscle cells at first 1 h, then induced cellular movement of immune cells such as granulocytes, neutrophils and lymphocytes at 6h, and activated IL-6 signaling pathway at 12h within NALT. These activation of immune cells also promoted signaling pathway for high-mobility group box 1 protein (HMGB1), followed by the maturation of DCs required for mucosal immunity. The CNs also triggered the response to other organism and inflammatory response, showing it is immune-enhancing adjuvant. The ELISA showed that significant production of specific IgA was detected in the fecal excretions and genital secretions from the CNs-Mdh-immunized group after 2 weeks-post immunization. Collectively, these results suggest that B. abortus Mdh-loaded CNs triggers activation of HMGB1, IL-6 and DCs maturation signaling within NALT and induce production of systemic IgG and IgA.

Viral Coinfection Replaces Effects of Suilysin on Streptococcus suis Adherence to and Invasion of Respiratory Epithelial Cells Grown under Air-Liquid Interface Conditions

Streptococcus suis is an important zoonotic pathogen which can infect humans and pigs worldwide, posing a potential risk to global public health. Suilysin, a pore-forming cholesterol-dependent cytolysin, is considered to play an important role in the pathogenesis of S. suis infections. It is known that infection with influenza A viruses may favor susceptibility to secondary bacterial infection, resulting in more severe disease and increased mortality. However, the molecular mechanisms underlying these coinfections are incompletely understood. Applying highly differentiated primary porcine respiratory epithelial cells grown under air-liquid interface (ALI) conditions, we analyzed the contribution of swine influenza viruses (SIV) to the virulence of S. suis, with a special focus on its cytolytic toxin, suilysin. We found that during secondary bacterial infection, suilysin of S. suis contributed to the damage of well-differentiated respiratory epithelial cells in the early stage of infection, whereas the cytotoxic effects induced by SIV became prominent at later stages of infection. Prior infection by SIV enhanced the adherence to and colonization of porcine airway epithelial cells by a wild-type (wt) S. suis strain and a suilysin-negative S. suis mutant in a sialic acid-dependent manner. A striking difference was observed with respect to bacterial invasion. After bacterial monoinfection, only the wt S. suis strain showed an invasive phenotype, whereas the mutant remained adherent. When the epithelial cells were preinfected with SIV, the suilysin-negative mutant also showed an invasion capacity. Therefore, we propose that coinfection with SIV may compensate for the lack of suilysin in the adherence and invasion process of suilysin-negative S. suis.

Induction of Th2-related immune responses and production of systemic IgA in mice intranasally immunized with Brucella abortus malate dehydrogenase loaded chitosan nanoparticles

The aim of this study was to investigate the induction of mucosal immune responses by an important Brucella abortus antigen, malate dehydrogenase (Mdh), loaded in mucoadhesive chitosan nanoparticles (CNs) and immunized intranasally in a BALB/c mouse model. The production of cytokines was investigated in human leukemic monocyte cells (THP-1 cells) after stimulation with the nanoparticles. Mdh-loaded CNs (CNs-Mdh) induced higher interleukin (IL)-6 production than unloaded antigens and TF loaded CNs (CNs-TF). Using ELISpot to quantify cytokines and antibody-secreting cells in the intranasally immunized mice, IL-4 and IgG-secreting cells were found to be significantly increased at 4 weeks and 6 weeks post-immunization in the CNs-Mdh immunized group, respectively. Increases in Mdh-specific IgG, IgG1, and IgG2a antibodies were confirmed at 6 weeks after immunization, indicating a predominant IgG1 response. Analysis of the mucosal immune response in the intranasally immunized mice revealed, Mdh-specific IgA and total IgA in the nasal washes, genital secretions, fecal extracts and sera that were remarkably increased in the CNs-Mdh-immunized group compared to the CNs-TF-immunized group except total IgA of nasal wash. Therefore, the results indicated that the intranasal immunization of CNs-loaded B. abortus Mdh antigen effectively induced antigen-specific mucosal immune responses through the elicitation of Th2-related immune responses.

Resveratrol and ivacaftor are additive G551D CFTR-channel potentiators: therapeutic implications for cystic fibrosis sinus disease

BACKGROUND

Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene result in defective Cl^- transport and cause chronic bacterial infections in the upper and lower airways of cystic fibrosis (CF) patients. Ivacaftor is a CFTR potentiator that improves Cl^- transport in CF patients with at least 1 copy of the G551D mutation. Resveratrol is also a potent CFTR potentiator that increases determinants of mucociliary transport. The objective of this study is to determine whether resveratrol and ivacaftor improve Cl^- secretion in G551D CFTR over either agent alone.

METHODS

Fisher rat thyroid cells (FRT) transfected with G551D CFTR and human sinonasal epithelial cells (HSNE) containing the CFTR G551D mutation were subjected to pharmacologic manipulation of transepithelial ion transport in Ussing chambers. Activity was further evaluated using whole-cell patch clamp methods in G551D FRT cells.

RESULTS

In G551D FRT cells, resveratrol (100 μM) and ivacaftor (10 μM) significantly increased Cl^- transport (change in short-circuit current, δI_SC = μA/cm² ) compared with single-agent and dimethylsulfoxide vehicle controls (resveratrol + ivacaftor 4.97 ± 0.57 vs ivacaftor 0.74 ± 0.12 vs resveratrol 2.96 ± 0.52 vs control 0.74 ± 0.12; p < 0.001). Maximal Cl^- secretion (20 μM forskolin) was also significantly enhanced (p < 0.0001). Activity was confirmed in G551D HSNE (resveratrol + ivacaftor 4.48 ± 0.39 vs ivacaftor 1.05 ± 0.11 vs. resveratrol 0.84 ± 0.3 vs control, 0.0 ± 0.02; p < 0.001), and whole-cell patch clamp analysis in G551D FRT cells (resveratrol + ivacaftor -2535 ± 179.3 pA vs ivacaftor -1408.9 ± 101.3 pA vs resveratrol; -766.2 ± 71.2 pA; p < 0.0001).

CONCLUSION

Additive improvement in G551D CFTR-mediated Cl^- secretion suggests that resveratrol could enhance ivacaftor therapy in these patients and improve CF-related rhinosinusitis.

Pulmonary delivery of polyplexes for combined PAI-1 gene silencing and CXCR4 inhibition to treat lung fibrosis

This report describes the development of polyplexes based on CXCR4-inhibiting poly(ethylenimine) derivative (PEI-C) for pulmonary delivery of siRNA to silence plasminogen activator inhibitor-1 (siPAI-1) as a new combination treatment of pulmonary fibrosis (PF). Safety and delivery efficacy of the PEI-C/siPAI-1 polyplexes was investigated in vitro in primary lung fibroblasts isolated from mice with bleomycin-induced PF. Biodistribution analysis following intratracheal administration of fluorescently labeled polyplexes showed prolonged retention in the lungs. Treatment of mice with bleomycin-induced PF using the PEI-C/siPAI-1 polyplexes resulted in a significant down-regulation of the PAI-1 expression and decreased collagen deposition in the lung. The results of this study provide first evidence of the potential benefits of combined inhibition of CXCR4 and PAI-1 in the pulmonary treatment of PF.

The role of mucus on drug transport and its potential to affect therapeutic outcomes

A layer of mucus covers the surface of all wet epithelia throughout the human body. Mucus is a hydrogel mainly composed of water, mucins (glycoproteins), DNA, proteins, lipids, and cell debris. This complex composition yields a tenacious viscoelastic hydrogel that lubricates and protects the exposed epithelia from external threats and enzymatic degradation. The natural protective role of mucus is nowadays acknowledged as a major barrier to be overcome in non-invasive drug delivery. The heterogeneity of mucus components offers a wide range of potential chemical interaction sites for macromolecules, while the mesh-like architecture given to mucus by the intermolecular cross-linking of mucin molecules results in a dense network that physically, and in a size-dependent manner, hinders the diffusion of nanoparticles through mucus. Consequently, drug diffusion, epithelial absorption, drug bioavailability, and ultimately therapeutic outcomes of mucosal drug delivery can be attenuated.

Assessment of acquired mucociliary clearance defects using micro-optical coherence tomography

BACKGROUND

Dehydration of airway surface liquid (ASL) disrupts normal mucociliary clearance (MCC) in sinonasal epithelium, which may lead to chronic rhinosinusitis (CRS). Abnormal chloride (Cl^- ) transport is one such mechanism that contributes to this disorder and can be acquired secondary to environmental perturbations, such as hypoxia at the tissue surface. The objective of this study was to assess the technological feasibility of the novel micro-optical coherence tomography (μOCT) imaging technique for investigating acquired MCC defects in cultured human sinonasal epithelial (HSNE) cells.

METHODS

Primary HSNE cell cultures were subjected to a 1% oxygen environment for 12 hours to induce acquired cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction. Ion transport characteristics were assessed with pharmacologic manipulation in Ussing chambers. ASL, periciliary fluid (PCL), and ciliary beat frequency (CBF) were evaluated using μOCT.

RESULTS

Amiloride-sensitive transport (ΔI_SC ) was greater in cultures exposed to hypoxia (hypoxia: -13.2 ± 0.6 μA/cm² ; control: -6.5 ± 0.1 μA/cm² ; p < 0.01), whereas CFTR-mediated anion transport was significantly diminished (hypoxia: 28.6 ± 0.3 μA/cm² ; control: 36.2 ± 1.6 μA/cm² ; p < 0.01), consistent with acquired CFTR dysfunction and sodium hyperabsorption. Hypoxia diminished all markers of airway surface function microanatomy as observed with μOCT, including ASL (hypoxia: 5.0 ± 0.4 μm; control: 9.0 ± 0.9 μm; p < 0.01) and PCL depth (hypoxia: 2.5 ± 0.1 μm; control: 4.8 ± 0.3 μm; p < 0.01), and CBF (hypoxia: 8.7 ± 0.3 Hz; control: 10.2 ± 0.3 Hz; p < 0.01).

CONCLUSION

Hypoxia-induced defects in epithelial anion transport in HSNE led to predictable effects on markers of MCC measured with novel μOCT imaging. This imaging method represents a technological leap forward and is feasible for assessing acquired defects impacting the airway surface.

A novel two-step sequential bioaccessibility test for potentially toxic elements in inhaled particulate matter transported into the gastrointestinal tract by mucociliary clearance

A novel two-step sequential extraction has been developed to assess the bioaccessibility of As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn in airborne particulate matter following inhalation and transport into the human gastrointestinal tract by mucociliary clearance. A new artificial mucus fluid (AMF) was used to determine the bioaccessible potentially toxic element (PTE) fraction in the upper airways, in sequence with the simplified bioaccessibility extraction test (SBET) or the stomach phase of the unified bioaccessibility method (gastric fluid only) (UBMG). Filter dynamic measurement system TX40 filters smeared with soil reference material (BGS RM 102) were used as test samples. Analysis was performed by ICP-MS. Comparison between results obtained for soil alone and when the soil was supported on TX40 filters indicated that the presence of the substrate did not affect the extraction efficiency, although a large Zn blank was detected. The sequential AMF→SBET extraction liberated similar amounts of Fe, Mn, Ni and Zn to the SBET alone; but significantly less Cd; and significantly more As, Cr, Cu and Pb. The sequential AMF→UBMG extraction liberated similar amounts of Cd, Cr, Mn and Zn to the UBMG alone, but significantly less As, Fe and Ni; and significantly more Cu and Pb. Enhanced extractability was due to the greater quantities of exchangeable ions and complexing agents present. Adoption of a two-step sequential extraction (AMF followed by either the SBET or the UBMG) is recommended because it is more representative of biological conditions and avoids overestimation or underestimation of bioaccessible PTE concentrations.

Graphical Abstract

A randomised controlled trial on the effect of inhaled hypertonic saline on quality of life in primary ciliary dyskinesia

Hypertonic saline inhalation lowers airway mucous viscosity. Increased cough transportability may improve quality of life (QoL) in primary ciliary dyskinesia (PCD).In this randomised controlled trial (RCT), PCD patients received twice-daily inhalations of hypertonic (7%) saline or isotonic (0.9%) saline for 12 weeks, with 4 weeks washout during crossover. Primary outcome was change in QoL measured by the St George's Respiratory Questionnaire (SGRQ) total score. Secondary outcomes were SGRQ subscores, Quality of Life Questionnaire-Bronchiectasis (QoL-B) scores, lower respiratory tract infection symptoms, exacerbations, spirometry, systemic and sputum inflammatory markers, adherence, and adverse events.There was no significant change in median (interquartile range) SGRQ total score between hypertonic saline (-2.6 (-9.0-1.5)) and isotonic saline (-0.3 (-8.1-6.1)) in 22 patients (age range 22-73 years) (p=0.38). QoL-B Health Perception scale improved with hypertonic saline (p=0.03). Adverse events occurred more frequently with hypertonic saline, but were mild.12 weeks of inhaled hypertonic saline did not improve SGRQ total score in adult PCD patients in this RCT, but the sample size was small. On the secondary and more disease-specific end-point of the QoL-B, a significant improvement was observed in the Health Perception scale. This study found little evidence to support the hypothesis that hypertonic saline improves QoL in PCD patients. We advise the use of disease-specific outcome measures in future trials.

Ambient Ultrafine Particle Ingestion Alters Gut Microbiota in Association with Increased Atherogenic Lipid Metabolites

Ambient particulate matter (PM) exposure is associated with atherosclerosis and inflammatory bowel disease. Ultrafine particles (UFP, d_p < 0.1–0.2 μm) are redox active components of PM. We hypothesized that orally ingested UFP promoted atherogenic lipid metabolites in both the intestine and plasma via altered gut microbiota composition. Low density lipoprotein receptor-null (Ldlr^−/−) mice on a high-fat diet were orally administered with vehicle control or UFP (40 μg/mouse/day) for 3 days a week. After 10 weeks, UFP ingested mice developed macrophage and neutrophil infiltration in the intestinal villi, accompanied by elevated cholesterol but reduced coprostanol levels in the cecum, as well as elevated atherogenic lysophosphatidylcholine (LPC 18:1) and lysophosphatidic acids (LPAs) in the intestine and plasma. At the phylum level, Principle Component Analysis revealed significant segregation of microbiota compositions which was validated by Beta diversity analysis. UFP-exposed mice developed increased abundance in Verrocomicrobia but decreased Actinobacteria, Cyanobacteria, and Firmicutes as well as a reduced diversity in microbiome. Spearman’s analysis negatively correlated Actinobacteria with cecal cholesterol, intestinal and plasma LPC18:1, and Firmicutes and Cyanobacteria with plasma LPC 18:1. Thus, ultrafine particles ingestion alters gut microbiota composition, accompanied by increased atherogenic lipid metabolites. These findings implicate the gut-vascular axis in a atherosclerosis model.

Lung bioaccessibility of contaminants in particulate matter of geological origin

Human exposure to particulate matter (PM) has been associated with adverse health effects. While inhalation exposure to airborne PM is a prominent research subject, exposure to PM of geological origin (i.e., generated from soil/soil-like material) has received less attention. This review discusses the contaminants in PM of geological origin and their relevance for human exposure and then evaluates lung bioaccessibility assessment methods and their use. PM of geological origin can contain toxic elements as well as organic contaminants. Observed/predicted PM lung clearance times are long, which may lead to prolonged contact with lung environment. Thus, certain exposure scenarios warrant the use of in vitro bioaccessibility testing to predict lung bioavailability. Limited research is available on lung bioaccessibility test development and test application to PM of geological origin. For in vitro tests, test parameter variation between different studies and concerns about physiological relevance indicate a crucial need for test method standardization and comparison with relevant animal data. Research is recommended on (1) developing robust in vitro lung bioaccessibility methods, (2) assessing bioaccessibility of various contaminants (especially polycyclic aromatic hydrocarbons (PAHs)) in PM of diverse origin (surface soils, mine tailings, etc.), and (3) risk characterization to determine relative importance of exposure to PM of geological origin.

Nasal immunization with mannan-decorated mucoadhesive HPMCP microspheres containing ApxIIA toxin induces protective immunity against challenge infection with Actinobacillus pleuropneumoiae in mice

The development of subunit mucosal vaccines requires an appropriate delivery system or an immune modulator such as an adjuvant to improve antigen immunogenicity. The nasal route for vaccine delivery by microparticles has attracted considerable interest, although challenges such as the rapid mucociliary clearance in the respiratory mucosa and the low immunogenicity of subunit vaccine still remain. Here, we aimed to develop mannan-decorated mucoadhesive thiolated hydroxypropylmethyl cellulose phthalate (HPMCP) microspheres (Man-THM) that contain ApxIIA subunit vaccine - an exotoxin fragment as a candidate for a subunit nasal vaccine against Actinobacillus pleuropneumoniae. For adjuvant activity, mucoadhesive thiolated HPMCP microspheres decorated with mannan could be targeted to the PRRs (pathogen recognition receptors) and mannose receptors (MR) of antigen presenting cells (APCs) in the respiratory immune system. The potential adjuvant ability of Man-THM for intranasal immunization was confirmed by in vitro and in vivo experiments. In a mechanistic study using APCs in vitro, it was found that Man-THM enhanced receptor-mediated endocytosis by stimulating the MR of APCs. In vivo, the nasal vaccination of ApxIIA-loaded Man-THM in mice resulted in higher levels of mucosal sIgA and serum IgG than mice in the ApxIIA and ApxIIA-loaded THM groups due to the specific recognition of the mannan in the Man-THM by the MRs of the APCs. Moreover, ApxIIA-containing Man-THM protected immunized mice when challenged with strains of A. pleuropneumoniae serotype 5. These results suggest that mucoadhesive Man-THM may be a promising candidate for a nasal vaccine delivery system to elicit systemic and mucosal immunity that can protect from pathogenic bacteria infection.

Treatment recommendations in Primary Ciliary Dyskinesia

Primary Ciliary Dyskinesia (PCD) is a rare heterogenic disorder leading to significant respiratory morbidity. Health-care providers who treat PCD must familiarize themselves with recommended treatment strategies. However, most of the treatments recommended in PCD have been extrapolated from cystic fibrosis (CF) and non-CF bronchiectasis literature. Mainstays of therapy are reviewed in detail, and should include at a minimum: regular airway clearance, routine microbiological surveillance, antibiotic treatment for pulmonary exacerbation, and health vaccinations. This review summarizes both medical and surgical pulmonary treatment considerations, as well as recommendations for the integration of non-pulmonary subspecialty care in the management of PCD.

Diagnosis, monitoring, and treatment of primary ciliary dyskinesia: PCD foundation consensus recommendations based on state of the art review

Primary ciliary dyskinesia (PCD) is a genetically heterogeneous, rare lung disease resulting in chronic oto-sino-pulmonary disease in both children and adults. Many physicians incorrectly diagnose PCD or eliminate PCD from their differential diagnosis due to inexperience with diagnostic testing methods. Thus far, all therapies used for PCD are unproven through large clinical trials. This review article outlines consensus recommendations from PCD physicians in North America who have been engaged in a PCD centered research consortium for the last 10 years. These recommendations have been adopted by the governing board of the PCD Foundation to provide guidance for PCD clinical centers for diagnostic testing, monitoring, and appropriate short and long-term therapeutics in PCD patients.

Cilia dysfunction in lung disease

A characteristic feature of the human airway epithelium is the presence of ciliated cells bearing motile cilia, specialized cell surface projections containing axonemes composed of microtubules and dynein arms, which provide ATP-driven motility. In the airways, cilia function in concert with airway mucus to mediate the critical function of mucociliary clearance, cleansing the airways of inhaled particles and pathogens. The prototypical disorder of respiratory cilia is primary ciliary dyskinesia, an inherited disorder that leads to impaired mucociliary clearance, to repeated chest infections, and to the progressive destruction of lung architecture. Numerous acquired lung diseases are also marked by abnormalities in both cilia structure and function. In this review we summarize current knowledge regarding airway ciliated cells and cilia, how they function to maintain a healthy epithelium, and how disorders of cilia structure and function contribute to inherited and acquired lung disease.

Primary ciliary dyskinesia assessment by means of optical flow analysis of phase-contrast microscopy images

Primary ciliary dyskinesia implies cilia with defective or total absence of motility, which may result in sinusitis, chronic bronchitis, bronchiectasis and male infertility. Diagnosis can be difficult and is based on an abnormal ciliary beat frequency (CBF) and beat pattern. In this paper, we present a method to determine CBF of isolated cells through the analysis of phase-contrast microscopy images, estimating cilia motion by means of an optical flow algorithm. After having analyzed 28 image sequences (14 with a normal beat pattern and 14 with a dyskinetic pattern), the normal group presented a CBF of 5.2 ± 1.6 Hz, while the dyskinetic patients presented a 1.9 ± 0.9 Hz CBF. The cutoff value to classify a dyskinetic specimen was set to 3.45 Hz (sensitivity 0.86, specificity 0.93). The presented methodology has provided excellent results to objectively diagnose PCD.

Comparison of cystic fibrosis transmembrane conductance regulator (CFTR) and ciliary beat frequency activation by the CFTR Modulators Genistein, VRT-532, and UCCF-152 in primary sinonasal epithelial cultures

IMPORTANCE

Pharmacologic activation of mucociliary clearance (MCC) represents an emerging therapeutic strategy for patients with chronic rhinosinusitis, even in the absence of congenital mutations of the CFTR gene. Drug discovery efforts have identified small molecules that activate the cystic fibrosis transmembrane conductance regulator (CFTR), including potentiators under development for treatment of cystic fibrosis.

OBJECTIVE

To evaluate the properties of CFTR modulators and their effects on ciliary beat frequency (CBF) in human sinonasal epithelium (HSNE).

DESIGN

Primary HSNE cultures (wild type and F508del/F508del) were used to compare stimulation of CFTR-mediated Cl- conductance and CBF by the CFTR modulators genistein, VRT-532, and UCCF-152.

MAIN OUTCOMES AND MEASURES

Increase in CFTR-dependent anion transport and CBF.

RESULTS

HSNE cultures were analyzed using pharmacologic manipulation of ion transport (change in short-circuit current [∆ISC]) and high-speed digital imaging (CBF). Activation of CFTR-dependent anion transport was significantly different among agonists (P < .001), with genistein exerting the greatest effect (mean [SD] ∆ISC, genistein, 23.1 [1.8] μA/cm2² > VRT-532, 8.1 [1.0] μA/cm² > UCCF-152, 3.4 [1.4] μA/cm² > control, 0.7 [0.2] μA/cm²; Tukey-Kramer P < .05) in the absence of forskolin. Genistein and UCCF-152 augmented CBF (under submerged conditions) significantly better (Tukey-Kramer P < .05) than cells treated with VRT-532 or dimethyl sulfoxide vehicle control (mean [SD] fold change over baseline, genistein, 1.63 [0.06]; UCCF-152, 1.56 [0.06]; VRT-532, 1.38 [0.08]; control, 1.27 [0.02]). Activation of CBF was blunted in F508del/F508del HSNE cultures.

CONCLUSIONS AND RELEVANCE

The degree of CBF stimulation was not dependent on the magnitude of Cl- secretion, suggesting that different mechanisms of action may underlie MCC activation by these small molecule potentiators. Agents that activate both CFTR-dependent ISC and CBF are particularly attractive as therapeutics because they may address 2 independent pathways that contribute to deficient MCC in chronic rhinosinusitis.

Resveratrol enhances airway surface liquid depth in sinonasal epithelium by increasing cystic fibrosis transmembrane conductance regulator open probability

BACKGROUND

Chronic rhinosinusitis engenders enormous morbidity in the general population, and is often refractory to medical intervention. Compounds that augment mucociliary clearance in airway epithelia represent a novel treatment strategy for diseases of mucus stasis. A dominant fluid and electrolyte secretory pathway in the nasal airways is governed by the cystic fibrosis transmembrane conductance regulator (CFTR). The objectives of the present study were to test resveratrol, a strong potentiator of CFTR channel open probability, in preparation for a clinical trial of mucociliary activators in human sinus disease.

METHODS

Primary sinonasal epithelial cells, immortalized bronchoepithelial cells (wild type and F508del CFTR), and HEK293 cells expressing exogenous human CFTR were investigated by Ussing chamber as well as patch clamp technique under non-phosphorylating conditions. Effects on airway surface liquid depth were measured using confocal laser scanning microscopy. Impact on CFTR gene expression was measured by quantitative reverse transcriptase polymerase chain reaction.

RESULTS

Resveratrol is a robust CFTR channel potentiator in numerous mammalian species. The compound also activated temperature corrected F508del CFTR and enhanced CFTR-dependent chloride secretion in human sinus epithelium ex vivo to an extent comparable to the recently approved CFTR potentiator, ivacaftor. Using inside out patches from apical membranes of murine cells, resveratrol stimulated an ~8 picosiemens chloride channel consistent with CFTR. This observation was confirmed in HEK293 cells expressing exogenous CFTR. Treatment of sinonasal epithelium resulted in a significant increase in airway surface liquid depth (in µm: 8.08+/-1.68 vs. 6.11+/-0.47,control,p<0.05). There was no increase CFTR mRNA.

CONCLUSION

Resveratrol is a potent chloride secretagogue from the mucosal surface of sinonasal epithelium, and hydrates airway surface liquid by increasing CFTR channel open probability. The foundation for a clinical trial utilizing resveratrol as a therapeutic intervention to increase mucociliary transport and airway surface liquid hydration in sinus disease is strongly supported by these findings.

Lung clearance index and high-resolution computed tomography scores in primary ciliary dyskinesia

RATIONALE

Lung clearance index (LCI) is a more sensitive measure of lung function than spirometry in cystic fibrosis (CF) and correlates well with abnormalities in high-resolution computed tomography (HRCT) scanning. We hypothesized LCI would be equally sensitive to lung disease in primary ciliary dyskinesia (PCD).

OBJECTIVES

To test the relationships between LCI, spirometry, and HRCT in PCD and to compare them to the established relationships in CF.

METHODS

Cross-sectional study of 127 patients with CF and 33 patients with PCD, all of whom had spirometry and LCI, of which a subset of 21 of each had HRCT performed. HRCT was scored for individual features and these features compared with physiological parameters.

MEASUREMENTS AND MAIN RESULTS

Unlike in CF, and contrary to our hypothesis, there was no correlation between spirometry and LCI in PCD and no correlation between HRCT features and LCI or spirometry in PCD.

CONCLUSIONS

We show for the first time that HRCT, spirometry, and LCI have different relationships in different airway diseases and that LCI does not appear to be a sensitive test of airway disease in advanced PCD. We hypothesize that this results from dissimilarities between the components of large and small airway disease in CF and PCD. These differences may in part lead to the different prognosis in these two neutrophilic airway diseases.

Superparamagnetic iron oxide nanoparticles (SPIONs)-loaded Trojan microparticles for targeted aerosol delivery to the lung

Targeted aerosol delivery to specific regions of the lung may improve therapeutic efficiency and minimise unwanted side effects. Targeted delivery could potentially be achieved with porous microparticles loaded with superparamagnetic iron oxide nanoparticles (SPIONs)-in combination with a target-directed magnetic gradient field. The aim of this study was to formulate and evaluate the aerodynamic properties of SPIONs-loaded Trojan microparticles after delivery from a dry powder inhaler. Microparticles made of SPIONs, PEG and hydroxypropyl-β-cyclodextrin (HPβCD) were formulated by spray drying and characterised by various physicochemical methods. Aerodynamic properties were evaluated using a next generation cascade impactor (NGI), with or without a magnet positioned at stage 2. Mixing appropriate proportions of SPIONs, PEG and HPβCD allowed Trojan microparticle to be formulated. These particles had a median geometric diameter of 2.8±0.3μm and were shown to be sensitive to the magnetic field induced by a magnet having a maximum energy product of 413.8kJ/m(3). However, these particles, characterised by a mass median aerodynamic diameter (MMAD) of 10.2±2.0μm, were considered to be not inhalable. The poor aerodynamic properties resulted from aggregation of the particles. The addition of (NH4)2CO3 and magnesium stearate (MgST) to the formulation improved the aerodynamic properties of the Trojan particles and resulted in a MMAD of 2.2±0.8μm. In the presence of a magnetic field on stage 2 of the NGI, the amount of particles deposited at this stage increased 4-fold from 4.8±0.7% to 19.5±3.3%. These Trojan particles appeared highly sensitive to the magnetic field and their deposition on most of the stages of the NGI was changed in the presence compared to the absence of the magnet. If loaded with a pharmaceutical active ingredient, these particles may be useful for treating localised lung disease such as cancer nodules or bacterial infectious foci.

Human inhalation exposure to iron oxide particles

In the past decade, many studies have been conducted to determine the health effects induced by exposure to engineered nanomaterials (NMs). Specifically for exposure via inhalation, numerous in vitro and animal in vivo inhalation toxicity studies on several types of NMs have been published. However, these results are not easily extrapolated to judge the effects of inhaling NMs in humans, and few published studies on the human response to inhalation of NMs exist. Given the emergence of more industries utilizing iron oxide nanoparticles as well as more nanomedicine applications of superparamagnetic iron oxide nanoparticles (SPIONs), this review presents an overview of the inhalation studies that have been conducted in humans on iron oxides. Both occupational exposure studies on complex iron oxide dusts and fumes, as well as human clinical studies on aerosolized, micron-size iron oxide particles are discussed. Iron oxide particles have not been described to elicit acute inhalation response nor promote lung disease after chronic exposure. The few human clinical studies comparing inhalation of fine and ultrafine metal oxide particles report no acute changes in the health parameters measured. Taken together existing evidence suggests that controlled human exposure to iron oxide nanoparticles, such as SPIONs, could be conducted safely.

Mechanosensitive ATP release maintains proper mucus hydration of airways

The clearance of mucus from the airways protects the lungs from inhaled noxious and infectious materials. Proper hydration of the mucus layer enables efficient mucus clearance through beating of cilia on airway epithelial cells, and reduced clearance of excessively concentrated mucus occurs in patients with chronic obstructive pulmonary disease and cystic fibrosis. Key steps in the mucus transport process are airway epithelia sensing and responding to changes in mucus hydration. We reported that extracellular adenosine triphosphate (ATP) and adenosine were important luminal autocrine and paracrine signals that regulated the hydration of the surface of human airway epithelial cultures through their action on apical membrane purinoceptors. Mucus hydration in human airway epithelial cultures was sensed by an interaction between cilia and the overlying mucus layer: Changes in mechanical strain, proportional to mucus hydration, regulated ATP release rates, adjusting fluid secretion to optimize mucus layer hydration. This system provided a feedback mechanism by which airways maintained mucus hydration in an optimum range for cilia propulsion. Understanding how airway epithelia can sense and respond to changes in mucus properties helps us to understand how the mucus clearance system protects the airways in health and how it fails in lung diseases such as cystic fibrosis.

Pullulan-based nanoparticles as carriers for transmucosal protein delivery

Polymeric nanoparticles have revealed very effective in transmucosal delivery of proteins. Polysaccharides are among the most used materials for the production of these carriers, owing to their structural flexibility and propensity to evidence biocompatibility and biodegradability. In parallel, there is a preference for the use of mild methods for their production, in order to prevent protein degradation, ensure lower costs and easier procedures that enable scaling up. In this work we propose the production of pullulan-based nanoparticles by a mild method of polyelectrolyte complexation. As pullulan is a neutral polysaccharide, sulfated and aminated derivatives of the polymer were synthesized to provide pullulan with a charge. These derivatives were then complexed with chitosan and carrageenan, respectively, to produce the nanocarriers. Positively charged nanoparticles of 180-270 nm were obtained, evidencing ability to associate bovine serum albumin, which was selected as model protein. In PBS pH 7.4, pullulan-based nanoparticles were found to have a burst release of 30% of the protein, which maintained up to 24h. Nanoparticle size and zeta potential were preserved upon freeze-drying in the presence of appropriate cryoprotectants. A factorial design was approached to assess the cytotoxicity of raw materials and nanoparticles by the metabolic test MTT. Nanoparticles demonstrated to not cause overt toxicity in a respiratory cell model (Calu-3). Pullulan has, thus, demonstrated to hold potential for the production of nanoparticles with an application in protein delivery.

Cilia-driven particle and fluid transport over mucus-free mice tracheae

To date, there is only a fragmentary understanding of the fundamental mechanisms of airway mucociliary transport. Application of the latest measurement techniques can aid in deciphering the complex interplay between ciliary beat and airway surface liquid (ASL) transport. In the present study, direct, quasi-simultaneous measurements of the cilia-induced fluid and bead transport were performed to gain a better insight into both transport mechanisms. In this study cilia-induced periciliary liquid (PCL) transport is measured by means of micro Particle Image Velocimetry (μPIV) with neutrally buoyant tracers. Particle Tracking Velocimetry (PTV) with heavier polystyrene-ferrite beads is performed to simulate particle transport. Contrary to recent literature, in which the presence of mucus was deemed necessary to maintain periciliary liquid (PCL) transport, effective particle and fluid transport was measured in our experiments in the absence of mucus. In response to muscarine or ATP stimulation, maximum fluid transport rates of 250 μm/s at 15 μm distance to the tracheal epithelia were measured while bead transport rates over the epithelia surfaces reached 200 μm/s. We estimated that the mean bead transport is dominated by viscous drag compared to inertial fluid forces. Furthermore, mean bead transport velocities appear to be two orders of magnitude larger compared to bead sedimentation velocities. Therefore, beads are expected to closely follow the mean PCL flow in non-ciliated epithelium regions. Based on our results, we have shown that PCL transport can be directly driven by the cilia beat and that the PCL motion may be capable of driving bead transport by fluid drag.

The Novel Dry Extract BNO 1011 Stimulates Chloride Transport and Ciliary Beat Frequency in Human Respiratory Epithelial Cultures

Background

Herbal remedies predate written history and continue to be used more frequently than conventional pharmaceutical medications. The novel dry extract BNO 1011 is based on a combination of five herbs that is used to treat acute and chronic rhinosinusitis. We evaluated the pharmacologic effects of the novel dry extract BNO 1011 on human respiratory epithelial cultures specifically addressing electrolyte transport and cilia beat frequency (CBF).

Methods

Well-differentiated human bronchial epithelial cultures grown at an air–liquid interface were treated on the apical or basolateral surface with varying concentrations of dry extract BNO 1011. Changes in transepithelial sodium and chloride transport were determined in Ussing chambers under voltage-clamped conditions. Changes in CBF were determined using the Sissons-Ammons Video Analysis system (Ammons Engineering, Mt. Morris, MI).

Results

When applied to the apical surface, dry extract BNO 1011 activated forskolin-stimulated chloride secretion and ciliary beat in a dose-dependent fashion. Basolateral application of dry extract BNO 1011 did not alter the measured physiological properties.

Conclusion

Apical application of dry extract BNO 1011 stimulates both chloride secretion and CBF and therefore may augment mucociliary clearance.

Noncovalenly PEGylated CTGF siRNA/PDMAEMA complex for pulmonary treatment of bleomycin-induced lung fibrosis

On the basis of wide biomedical applications of methacrylate polymers, we previously developed noncovalently post-PEGylated ternary complex of siRNA using poly(dimethylamino)ethylmethacrylate (PDMAEMA) and its copolymer with poly(α-methylether-ω-methacrylate-ethyleneglycol) [PMAPEG]. In this work, we investigated the antifibrotic effect of connective tissue growth factor siRNA (siCTGF)/PDMAEMA/PDMAEMA-b-PMAPEG complex for the treatment of bleomycin-induced pulmonary fibrosis. After orotracheal administration to fibrotic Sprague Dawley (SD) model rats, FAM-labeled siCTGF complex was effectively delivered to the cells in the lung. The siCTGF ternary complex resulted in a significant reduction in target gene expression, collagen deposition, inflammatory cytokines production, and drastic attenuation of pulmonary fibrosis in pathophysiological analysis. Furthermore, the survival rate was remarkably increased to the statistically significant level in comparison with the scrambled siCTGF treatment group.

Transepithelial ion transport is suppressed in hypoxic sinonasal epithelium

OBJECTIVES/HYPOTHESIS

Sinonasal respiratory epithelial mucociliary clearance is dependent on the transepithelial transport of ions such as Cl(-) . The objectives of the present study were to investigate the role of oxygen restriction in 1) Cl(-) transport across primary sinonasal epithelial monolayers, 2) expression of the apical Cl(-) channels cystic fibrosis transmembrane conductance regulator (CFTR) and transmembrane protein 16A (TMEM16A), and 3) the pathogenesis of chronic rhinosinusitis.

STUDY DESIGN

In vitro investigation.

METHODS

Murine nasal septal epithelial (MNSE), wild type, and human sinonasal epithelial (HSNE) cultures were incubated under hypoxic conditions (1% O(2) , 5% CO(2) ). Cultures were mounted in Ussing chambers for ion transport measurements. CFTR and TMEM16A expression were measured using quantitative reverse-transcription polymerase chain reaction (RT-PCR).

RESULTS

The change in short-circuit current (ΔI(SC) in microamperes per square centimeter) attributable to CFTR (forskolin-stimulated) was significantly decreased due to a 12-hour hypoxia exposure in both MNSE (13.55 ± 0.46 vs. 19.23 ± 0.18) and HSNE (19.55 ± 0.56 vs. 25.49 ± 1.48 [control]; P < .05). TMEM16A (uridine triphosphate-stimulated transport) was inhibited by 48 hours of hypoxic exposure in MNSE (15.92 ± 2.87 vs. 51.44 ± 3.71 [control]; P < .05) and by 12 hours of hypoxic exposure in HSNE (16.75 ± 0.68 vs. 24.15 ± 1.35 [control]). Quantitative RT-PCR (reported as relative mRNA levels ± standard deviation) demonstrated significant reductions in both CFTR and TMEM16A mRNA expression in MNSE and HSNE owing to airway epithelial hypoxia.

CONCLUSIONS

Sinonasal epithelial CFTR and TMEM16A-mediated Cl(-) transport and mRNA expression were robustly decreased in an oxygen-restricted environment. These findings indicate that persistent hypoxia may lead to acquired defects in sinonasal Cl(-) transport in a fashion likely to confer mucociliary dysfunction in chronic rhinosinusitis.

Resveratrol has salutary effects on mucociliary transport and inflammation in sinonasal epithelium

OBJECTIVE/HYPOTHESIS

Therapeutic agents that enhance mucociliary transport (via stimulation of transepithelial Cl- secretion) and inhibit inflammation could provide considerable advantages over conventional treatments for chronic rhinosinusitis (CRS). The objectives of the present study were to investigate whether the polyphenolic compound resveratrol promotes transepithelial Cl- transport and inhibits KC/IL-8 secretion in sinonasal epithelium.

STUDY DESIGN

In vitro and in vivo study.

METHODS

Transepithelial Cl- transport was investigated in primary murine nasal septal (MNSE) and human sinonasal epithelial (HSNE) cultures. In vivo activity was also measured using the murine nasal potential difference assay. CFTR R-domain phosphorylation and cAMP levels were examined as a test of cAMP/PKA-dependent activation. In vitro LPS-induced KC/IL-8 secretion was quantified and compared to a panel of intranasal steroids.

RESULTS

Resveratrol(100 μM) significantly increased CFTR-mediated Cl- transport (change in short-circuit current, ΔI(SC) ) in both MNSE (13.51 ± 0.77 vs. 4.4 ± 0.66 [control]; P < .05) and HSNE (12.28 ± 1.08 vs. 0.69 ± 0.32 [control]; P < .05). Cl- secretion across in vivo murine nasal epithelium was also enhanced (-4 ± 1.8 vs. -0.8 ± 1.7mV [control], P < .05). There was no increase in cellular cAMP or CFTR R-domain phosphorylation detected. Resveratrol also significantly inhibited KC/IL-8 secretion in a dose-dependent fashion (pg/mL) in MNSE (181 ± 39[100 μM) vs. 94 ± 16 [200 μM] vs. 16 ± 22 [500 μM] vs. 1195 ± 355 [LPS control]; P < .001). The compound robustly abrogated KC/IL-8 secretion when compared to ciclesonide (765 ± 139), triamcinolone (561 ± 124), and budesonide (742 ± 428), but had similar activity to fluticasone proprionate (65 ± 47). Similar effects were demonstrated in HSNE (975 ± 244 [100 μM] vs. 1825 ± 144 [LPS control]; P < .001) with inhibition comparable to fluticasone proprionate (785 ± 277).

CONCLUSIONS

These in vitro and in vivo findings indicate resveratrol is a potent Cl- secretagogue and anti-inflammatory agent. Future clinical trials for CRS are warranted.

Exposure to cigarette smoke condensate reduces calcium activated chloride channel transport in primary sinonasal epithelial cultures

OBJECTIVES/HYPOTHESIS

The cystic fibrosis transmembrane conductance regulator (CFTR) serves as a predominant Cl(-) transport conduit in airway epithelium and is inhibited by cigarette smoke in vitro and in vivo. Activation of secondary Cl(-) transport pathways through calcium-activated Cl(-) channels (CaCC) has been postulated as a mechanism to bypass defects in CFTR-mediated transport. Because it is not known whether CaCCs are also inhibited by tobacco exposure, the current study was designed to investigate the effect of cigarette smoke condensate (CSC) on CaCC transport.

STUDY DESIGN

In vitro study.

METHODS

Well-characterized primary murine nasal septal epithelial (MNSE) and human sinonasal epithelial (HSNE) cultures were exposed to CSC in Ussing chambers. We monitored CaCC short-circuit current through stimulation of P2Y purinergic receptors with uridine triphosphate or adenosine triphosphate and selective inhibition of the CFTR-dependent secretory pathway. Characterization of CaCC current was also accomplished in primary airway cells derived from transgenic CFTR(-/-) (knockout) murine models.

RESULTS

Change in CaCC-mediated current (DeltaI(SC) representing transepithelial Ca-mediated Cl(-) secretion in muA/cm(2)) was significantly decreased in CSC-exposed wild type MNSE when compared to controls (32.8 +/- 4.6 vs. 47.5 +/- 2.3; respectively; P < .02). A similar effect was demonstrated in CFTR(-/-) MNSE cultures (33.4 +/- 2.8 vs. 38.6 +/- 2.0; P < .05>. HSNE cultures also had a significant reduction in I(SC) (16.1 +/- 0.6 vs. 22.7 +/- 0; P = .008).

CONCLUSIONS

CSC affects multiple pathways fundamental to airway ion transport, including both cyclic adenosine monophosphate and calcium activated Cl(-) transport. Inhibition of Cl(-) transport may contribute to common diseases of the airways, such as chronic rhinosinusitis and chronic obstructive pulmonary disease.

The bioflavonoid compound, sinupret, stimulates transepithelial chloride transport in vitro and in vivo

OBJECTIVES/HYPOTHESIS

Dehydration of airway surface liquid (ASL) disrupts normal mucociliary clearance in sinonasal epithelium leading to chronic rhinosinusitis. Abnormal chloride (Cl(-)) transport is one mechanism that contributes to this disorder, as demonstrated by the disease cystic fibrosis. Identifying safe compounds that stimulate transepithelial Cl(-) transport is critical to improving hydration of the ASL and promoting mucociliary transport. Sinupret (Bionorica, LLC, San Clemente, CA), a combination of naturally occurring bioflavonoids, is a widely used treatment for respiratory ailments in Europe. However, the effects of Sinupret on target respiratory epithelium have yet to be fully investigated. The present study evaluated the mechanisms underlying this bioflavonoid therapeutic on transepithelial Cl(-) transport in respiratory epithelium.

STUDY DESIGN

In vitro and in vivo investigation.

METHODS

Well characterized murine nasal septal epithelial (MNSE) cultures, and murine nasal potential difference (NPD) techniques were used to evaluate the effects of Sinupret on Cl(-) secretion.

RESULTS

The change in Sinupret-stimulated current (Delta I(SC) expressed as microA/cm(2)) in MNSE, representing Cl(-) secretion, was significantly increased when compared to controls (19.04 + or - 1.67 microA/cm(2) vs. 1.8 + or - 0.35 microA/cm(2), respectively; P = .00005). Transepithelial Cl(-) transport measured in the murine NPD in vivo assay (n = 42) was also significantly enhanced when compared to controls (-0.8 mV vs. -0.9 mV; P = .0004). Importantly, Sinupret-stimulated Cl(-) transport was substantially more robust in vivo than forskolin, a compound among the strongest known cystic fibrosis transmembrane conductance regulator activators (-3.8 mV vs. -1.65 mV; P = .01).

CONCLUSIONS

Sinupret strongly activates transepithelial Cl(-) secretion through a mechanism known to hydrate the ASL of respiratory epithelium. This is one means by which the medication is likely to exert therapeutic benefit.

Magnetometric evaluation of toxicities of chemicals to the lungs and cells

Because the lungs are exposed to airborne hazardous materials, alveolar macrophages (AMs) play a major role in defending against the exposure to various noxious chemical substances. In this study, we reviewed magnetometric investigations of the effects of various chemicals on the lungs and AMs. Magnetometry, using magnetite as an indicator, was used to evaluate the effects of certain chemicals on the lung and AMs. A rapid decrease of the remanent magnetic field after the cessation of external magnetization, a phenomenon called relaxation, was impaired when the lungs and macrophages were exposed to toxic substances. The delayed in vivo relaxation observed in the lungs exposed to magnetite and gallium arsenide was almost identical to the in vitro relaxation observed in the AMs exposed to the same materials. Delayed relaxation was observed in the AMs exposed to silica dust; various fibers, such as chrysotile and some man-made mineral fibers; and toxic arsenic and cadmium compounds. The extracellular release of lactate dehydrogenase activity was found in the AMs exposed to the chemicals. Relaxation is attributed to the cytoskeleton-driven rotation of phagosomes containing magnetite. While the exact mechanism of delayed relaxation due to exposure to harmful chemicals remains to be clarified, cell magnetometry appears to be useful for the safety screening of chemical substances.