Cilia and Mucociliary Clearance

Interplay of Mycobacterium abscessus and Pseudomonas aeruginosa in experimental models of coinfection: Biofilm dynamics and host immune response

The incidence of infection by nontuberculous mycobacteria, mainly Mycobacterium abscessus, is increasing in patients with cystic fibrosis and other chronic pulmonary diseases, leading to an accelerated lung function decline. In most cases, M. abscessus coinfects Pseudomonas aeruginosa, the most common pathogen in these conditions. However, how these two bacterial species interact during infection remains poorly understood. This study explored their behaviour in three relevant pathogenic settings: dual-species biofilm development using a recently developed method to monitor individual species in dual-species biofilms, coinfection in bronchial epithelial cells, and in vivo coinfection in the Galleria mellonella model. The results demonstrated that both species form stable mixed biofilms and reciprocally inhibit single-biofilm progression. Coinfections in bronchial epithelial cells significantly decreased cell viability, whereas in G. mellonella, coinfections induced lower survival rates than individual infections. Analysis of the immune response triggered by each bacterium in bronchial epithelial cell assays and G. mellonella larvae revealed that P. aeruginosa induces the overexpression of proinflammatory and melanization cascade responses, respectively. In contrast, M. abscessus and P. aeruginosa coinfection significantly inhibited the immune response in both models, resulting in worse consequences for the host than those generated by a single P. aeruginosa infection. Overall, this study highlights the novel role of M. abscessus in suppressing immune responses during coinfection with P. aeruginosa, emphasizing the clinical implications for the management of cystic fibrosis and other pulmonary diseases. Understanding these interactions could inform the development of new therapeutic strategies to mitigate the severity of coinfections in vulnerable patients.

Unique immune and other responses of human nasal epithelial cells infected with H5N1 avian influenza virus compared to seasonal human influenza A and B viruses

Highly pathogenic avian influenza (HPAI) virus (e.g. H5N1) infects the lower airway to cause severe infections, and constitute a prime candidate for the emergence of disease X. The nasal epithelium is the primary portal of entry for respiratory pathogens, serving as the airway's physical and immune barrier. While HPAI virus predominantly infects the lower airway, not much is known about its interactions with the nasal epithelium. Hence, we sought to elucidate and compare the differential responses of the nasal epithelium against HPAI infection that may contribute to its pathology, and to identify critical response markers. We infected human nasal epithelial cells (hNECs) cultured at the air-liquid interface from multiple healthy donors with clinical isolates of major human seasonal influenza viruses (H1N1, H3N2, influenza B) and HPAI H5N1. The infected cells were subjected to virologic, transcriptomic and secretory protein analyses. While less adapted to infecting the nasal epithelium, HPAI H5N1 elicited unique host responses unlike seasonal influenza. Interestingly, H5N1 infection of hNECs induced responses indicative of subdued antiviral activity (e.g. reduced expression of IFNβ, and inflammasome mediators, IL-1α and IL-1β); decreased wound healing; suppressed re-epithelialization; compromised epithelial barrier integrity; diminished responses to oxidative stress; and increased transmembrane solute and ion carrier gene expression. These unique molecular changes in response to H5N1 infection may represent potential targets for enhancing diagnostic and therapeutic strategies for better surveillance and management of HPAI infection in humans.

Magnetic pillar induced Poiseuille-like flow in microfluidic channels with viscous and viscoelastic fluids

Mucociliary clearance in mammals serves as the primary defense mechanism for removing particulate matter deposited in the pulmonary airways. Dysfunctions in this process are linked to serious respiratory diseases and can hinder effective drug delivery to the lungs. Microfluidic systems have emerged as a promising alternative for replicating lung functions in non-cellular physiological environments, offering a more controllable approach compared to in vivo and in vitro assays. Here we present a microfluidic platform featuring a closed-loop circular microchannel, integrating a thousand 75 μm-high magnetic pillars arranged in a square array. Made of polydimethylsiloxane and loaded with iron microparticles, the pillars are studied using scanning electron microscopy and magnetometry; their internal structure and bending response to a magnetic field are quantitatively analyzed. Using a combination of experimental data and finite element simulations, we found that the magnetic torque induced by permanent magnets dominates over magnetic force, generating fluid flow in the microchannel. Under the application of a rotating field, the time-dependent deflection of the pillars closely mimics the behavior of lung cilia, exhibiting alternating effective and recovery strokes. The velocity profiles of viscous and viscoelastic fluids are examined, and shown to display Poiseuille-type flow. By varying the viscosity of the fluids across four orders of magnitude, we identified a transition in propulsion regimes between viscous and elastic-driven flows. This active microfluidic platform offers a promising approach for modeling mucociliary clearance in drug delivery applications.

A comparative approach to bony changes in maxillary and frontal sinuses as indicators of upper respiratory health

OBJECTIVE

The central aspect of this study is to provide a detailed comparison of bony changes in the maxillary and frontal sinuses in human skeletal remains in an effort to assist researchers record lesions and assist with potential diagnoses.

MATERIALS

198 adult human remains from a medieval Avar population from Vienna, Austria.

METHODS

Analysis of bony changes using an endoscopic multifunctional camera with an ultra-small lens and adjustable LED lights.

RESULTS

Most common findings in both the maxillary and frontal sinuses are "pitting" and "white pitted bone". However, significant differences between the maxillary and frontal sinuses regarding the frequency and variation of bony lesions exist.

CONCLUSION

The maxillary sinuses exhibited significantly greater prevalence of bony changes compared to the frontal sinuses but frontal sinuses, which generally are less frequently affected by inflammatory, malignant, or benign lesions, may ultimately provide more informative insights in paleopathological studies concerning the health of the upper airways than the maxillary sinuses.

SIGNIFICANCE

Considering that most paleopathological studies on paranasal sinuses focus primarily on the maxillary sinuses, this study provides comparative data on the diversity of bony changes found in the frontal sinuses as a means to assist paleopathological recording and potentially eventual diagnosis.

LIMITATIONS

The lack of knowledge about the pathophysiological mechanisms underlying individual bony features complicates interpretation, particularly in paleopathological studies.

SUGGESTIONS FOR FURTHER RESEARCH

A further examination of all paranasal sinuses (including the sphenoid sinuses and ethmoidal cells) is recommended.

Pulmonary hazards of nanoplastic particles: a study using polystyrene in in vitro models of the alveolar and bronchial epithelium

BACKGROUND

Nanoplastics (NPs) are released into the environment through the degradation of plastic objects, leading to human exposure. Due to their small size, concerns have been raised about the potential hazards to the respiratory tract, as ultrafine and nanoparticles are known to penetrate till the alveolar regions of the lungs, potentially impairing their functions. Thus, in the present study, we used model polystyrene nanoparticles doped with the fluorescent metal europium (PS-Eu) to enhance the understanding of NPs hazard and investigate adverse outcomes associated with exposure in human lungs using alveolar (A549) and bronchial (Calu-3) cell models grown in 2D and 3D submerged conditions or quasi air-liquid interface (ALI) conditions (3D).

RESULTS

Briefly, after in-dept physicochemical characterization of the particles, we assessed their impact on ROS production, cell viability (AlamarBlue and lactate dehydrogenase assays) and barrier integrity (lucifer yellow assay and TEER measurement), finding no negative effects in either model. However, in alveolar cells, particles increased acidic organelle activity. Transmission electron microscopy and Raman microscopy showed, in both models, a dose- and cell-dependent particle uptake with PS-Eu accumulating in numerous and large endo-lysosomes, which, in transwells-grown A549 cells, often contained also lamellar bodies (LBs), organelles involved in surfactants storage and secretion. After extensively quantifying surfactant proteins (SP) in the pellet and supernatant fractions of treated A549 cells, we observed a significant reduction in several members of this family, including surfactant protein B, which is crucial for lamellar body formation and surface tension regulation in the lungs. In quasi-ALI Calu-3 cultures instead, PS-Eu significantly upregulated interleukin 6 (IL-6) and increased transforming growth factor beta β (TGF-β), zonula occludens 1 (ZO-1), and mucin (MUC) 5B mRNA expressions causing a moderate proinflammatory response.

CONCLUSION

Our results show that PS-Eu exposure does not induce acute cytotoxicity in these models, but affects cell-specific functions like surfactant, mucin, and cytokine production. This underscores the limitations of relying solely on standard cytotoxicity tests for particle hazard assessment and highlights the importance of investigating cell function-specific signaling pathways. To support researchers in hazard assessment, we propose specific classes of biomarkers to test in in vitro lung models.

Advances in Molecular Research of Tracheobronchial Tree Aging: A Systematic Review

Aging affects all tissues in an organism, including the tracheobronchial tree, with structural and functional changes driven by mechanisms such as oxidative stress, cellular senescence, epigenetic modifications, mitochondrial dysfunction, and telomere shortening. Airway aging can be accelerated by intrinsic or extrinsic factors. This review brings together information from the literature on the molecular changes occurring in all layers of the tracheobronchial airway wall. It examines the biomolecular changes associated with aging in the mucosa, submucosa, cartilage, and smooth muscle of the airways. At the mucosal level, aging reduces ciliary function and disrupts mucin homeostasis, impairing mucociliary clearance and contributing to chronic respiratory diseases such as COPD (Chronic Obstructive Pulmonary Disease). Cellular senescence and oxidative stress drive extracellular matrix remodeling and chronic inflammation. Airway cartilage undergoes age-related changes in collagen and fibronectin composition, leading to increased stiffness, while heightened MMP (Matrix Metalloproteinases) activity exacerbates ECM (extracellular matrix) degradation. In airway smooth muscle, aging induces changes in calcium signaling, hypertrophy, and the secretion of pro-inflammatory mediators, further perpetuating airway remodeling. These changes impair respiratory function and increase susceptibility to chronic respiratory conditions in the elderly. By consolidating current knowledge, this review aims to provide a comprehensive overview of the molecular changes occurring in the respiratory tract with aging and to highlight new molecular perspectives for future research on this topic.

Influence of Bifurcation Morphology on Exercise-Induced PAH Deposition in the Lungs: A Computational Modeling Approach for Air Quality Research

This study examines the influence of lung geometry, physical activity intensity, and aerosol concentration on the deposition efficiencies (DEs) of particulate matter with surface-bound polycyclic aromatic hydrocarbons (PM-PAHs) in human lung generations 3-6. Two-phase flows were effected in ANSYS 2020R2 platform using planar and orthogonal lung geometries, with two levels of physical activities, 4 metabolic equivalents (4 METs), and 8 METs. Aerosol concentrations of 0.95 μg‧m-3, 1.57 μg‧m-3, and 2.04 μg‧m-3 represent rural, urban, and industrial areas, respectively. Relative differences in DEs for 1 μm, 3.2 μm, and 5.6 μm exhibit variations between the two geometries with ranges of 0%-84.4% for 4 METs and 1.2%-50.7% for 8 METs. The first carina region was the most significant hotspot for the 5.6 μm particles. On the other hand, the 1 μm and 3.2 μm aerosols infiltrated and deposited evenly at the lower sections of the lungs. Regarding PM-PAHs doses, spatial variations indicate an industrial > urban > rural hierarchy. This investigation suggests that individuals in industrial and urban locations should manage the intensity of their outdoor activities to minimize exposure to PM-PAHs. These findings are instrumental for public health interventions aimed at reducing exposure to PM-PAHs and preventing associated health problems.

Centriolar defects underlie a primary ciliary dyskinesia phenotype in an adenylate kinase 7 deficient ciliated epithelium

The skin of Xenopus embryos contains numerous multiciliated cells (MCCs), which collectively generate a directed fluid flow across the epithelial surface essential for distributing the overlaying mucous. MCCs develop into highly specialized cells to generate this flow, containing approximately 150 evenly spaced centrioles that give rise to motile cilia. MCC-driven fluid flow can be impaired when ciliary dysfunction occurs, resulting in primary ciliary dyskinesia (PCD) in humans. Mutations in a large number of genes (∼50) have been found to be causative to PCD. Recently, studies have linked low levels of Adenylate Kinase 7 (AK7) gene expression to patients with PCD; however, the mechanism for this link remains unclear. Additionally, AK7 mutations have been linked to multiple PCD patients. Adenylate kinases modulate ATP production and consumption, with AK7 explicitly associated with motile cilia. Here we reproduce an AK7 PCD-like phenotype in Xenopus and describe the cellular consequences that occur with manipulation of AK7 levels. We show that AK7 localizes throughout the cilia in a DPY30 domain-dependent manner, suggesting a ciliary function. Additionally, we find that AK7 overexpression increases centriole number, suggesting a role in regulating centriole biogenesis. We find that in AK7-depleted embryos, cilia number, length, and beat frequency are all reduced, which in turn significantly decreases the tissue-wide mucociliary flow. Additionally, we find a decrease in centriole number and an increase in sub-apical centrioles, implying that AK7 influences both centriole biogenesis and docking, which we propose underlie its defect in ciliogenesis. We find that both the AK domain and the DPY30 domain are required for proper centriole regulation. We propose that AK7 plays a role in PCD by impacting centriole biogenesis and apical docking, ultimately leading to ciliogenesis defects that impair mucociliary clearance.

Peptides: potential delivery systems for mRNA

mRNA-based therapies have broad applications in various disease treatments and have been applied in protein replacement therapy, gene editing, and vaccine development. Numerous research studies have been carried out aiming to increase the stability of mRNA, improve its translational efficiency, and reduce its immunogenicity. However, given mRNA's large molecular size and strong electronegativity, the safety and efficient delivery of mRNA into the target cells remains the critical rate-limiting step in current mRNA drug development. Various nanocarriers, such as liposomes, lipid nanoparticles, polyetherimide, and mesoporous silica nanoparticles, have been employed for mRNA delivery in the past few decades. Among them, peptides have demonstrated great potential as promising carrier candidates for mRNA delivery due to their high cell membrane permeability, good biocompatibility, definite chemical structure, and ease of preparation. Here, peptide-based mRNA delivery systems are systematically analyzed, including their construction strategies, mechanisms of action in mRNA delivery, and the application limitations or challenges. It is hoped that this review will guide the design, optimization, and applications of peptide carriers in mRNA-based drug development.

Upper Respiratory Microbiome in Vasculitis

The pathogenesis of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), such as granulomatosis with polyangiitis, is not well understood. These diseases cause significant inflammation in the upper airway. The nares and upper airway are host to many commensal microbes as well as a frequent site of exposure to pathogenic microbes. This review explores the association between upper airway microbial dysregulation and AAV. The role of Staphylococcus aureus colonization as a possible driver of disease is discussed, as well as recent work exploring how fluctuations in the abundance and diversity of commensal microbes are related to vasculitis and risk of flare.

Exploring the influence of vaping on the pharmacokinetic fate of inhaled therapeutics

The surge of electronic cigarette use in Australia, especially amongst the younger population, raises significant concerns about its impact on respiratory health. This review focuses on the detrimental effects of vaping on pulmonary function, delving into oxidative stress, ventilation-perfusion mismatching, as well as cellular damage. Our findings show that e-cigarette use adversely affects the pharmacokinetics of inhaled therapies, reducing efficacy through impaired drug distribution, clearance and absorption, as well as alterations in metabolism. These negative effects mirror the impacts of traditional cigarette smoking, posing a severe health risk not only to individuals who vape, but also to those with pre-existing respiratory conditions. Despite its perception as a safer alternative, its consequence on pulmonary health is becoming increasingly evident with issues such as nicotine addiction and emerging evidence that even short-term exposure to e-cigarette aerosols impairs lung function, potentially paving the way for chronic respiratory diseases. This underscores an urgent need for further research on its long-term implications, particularly for individuals relying on inhalation therapies, emphasising the need for informed public health strategies and guiding clinical practice to safeguard respiratory health in this rapidly evolving landscape.

Scalable Laser Manufacturing of High-Aspect-Ratio Superhydrophobic and Ferromagnetic Microcilia Arrays for Aqueous Droplet Transportation

Biological cilia exhibit metachronal movements that enable the expulsion of substances such as mucus and bacterial cells. Inspired by biological cilia, significant progress has been made in recent years in the development of artificial cilia. In particular, magnetic actuation has emerged as a prominent strategy for real-time, remote-controlled manipulation, offering noninvasive and reversible operation without inducing irreversible damage. However, the fabrication of artificial microcilia is currently constrained by limitations in achieving high aspect ratios, cost-effectiveness, and scalable production. In this study, advanced laser manufacturing is used to drill porous silicon (Si) templates, successfully demolding microcilia with a high aspect ratio (exceeding 9). By integrating silicon dioxide (SiO2) nanoparticles, a superhydrophobic surface is achieved with a hierarchical micro-nano structure. The experiments demonstrated that these structured microcilia not only exhibit remarkable durability but also maintain long-term superhydrophobicity. Furthermore, by blending with magnetic iron (II, III) oxide (Fe3O4) nanoparticles, superhydrophobic magnetic microcilia arrays (SMMA) are developed, enabling droplet transportation on their surface controlled by an external magnetic field. These artificial microcilia have potential applications in biomedical devices, self-cleaning anti-fouling surfaces, and human sensing technologies.

Establishing a Xanthan Gum-Locust Bean Gum Mucus Mimic for Cystic Fibrosis Models: Yield Stress and Viscoelasticity Analysis

Airway mucus plays a critical role in respiratory health, with diseases such as cystic fibrosis (CF) being characterized by mucus that exhibits increased viscosity and altered viscoelasticity. In vitro models that emulate these properties are essential for understanding the impact of CF mucus on airway function and for the development of therapeutic strategies. This study characterizes a mucus mimic composed of xanthan gum and locust bean gum, which is designed to exhibit the rheological properties of CF mucus. Mucus concentrations ranging from 0.07% to 0.3% w/v were tested to simulate different states of bacterial infection in CF. Key rheological parameters, including yield stress, storage modulus, loss modulus, and viscosity, were measured using an HR2 rheometer with strain sweep, oscillation frequency, and flow ramp tests. The results show that increasing the concentration enhanced the mimic's elasticity and yield stress, with values aligning with those reported for CF mucus in pathological states. These findings provide a quantitative framework for tuning the rheological properties of mucus in vitro, allowing for the simulation of CF mucus across a range of concentrations. This mucus mimic is cost-effective, readily cross-linked, and provides a foundation for future studies examining the mechanobiological effects of mucus yield stress on epithelial cell layers, particularly in the context of bacterial infections and airway disease modeling.

Development and Characterization of a Primary Ciliated Porcine Airway Model for the Evaluation of In Vitro Mucociliary Clearance and Mucosal Drug Delivery

Background/Objectives: In vitro models play a crucial role in preclinical respiratory research, enabling the testing and screening of mucosal formulations, dosage forms, and inhaled drugs. Mucociliary clearance (MCC) is an essential defense mechanism in mucosal drug delivery but is often impaired in respiratory diseases. Despite its importance, standardized in vitro MCC assays are rarely reported. Furthermore, many published methods primarily measure cilia beat frequency (CBF), which requires high-speed cameras that are not accessible to all laboratories. Therefore, this study aimed to develop a physiologically relevant, differentiated in vitro model of the respiratory epithelium that incorporates both beating cilia and functional MCC. We chose porcine airway mucosa as an alternative to human tissue due to ethical considerations and limited availability. The established model is designed to provide a reproducible and accessible method for a broad range of research laboratories. Methods: The previously published tracheal mucosal primary cell (TMPC DS) model, derived from porcine tissue, lacked the presence of beating cilia, which are crucial for effective MCC analysis. For accurate MCC assessment, beating cilia are essential as they play a key role in mucus clearance. To address this limitation, the here-described ciliated tracheal mucosal primary cell (cTMPC) model was developed. cTMPCs were isolated from porcine tissue and cultured under air-liquid interface (ALI) conditions for 21 days to promote differentiation. This model was evaluated for cell morphology, tight junction formation, ciliated and mucus-producing cells, barrier function, gene expression, and tracer/IgG transport. MCC and the model's suitability for standardized MCC assays were assessed using an inverted microscope. In contrast to the TMPC DS model, which lacked beating cilia and thus could not support MCC analysis, the cTMPC model allows for comprehensive MCC studies. Results: The developed differentiated in vitro model demonstrated key structural and functional features of the respiratory epithelium, including well-differentiated cell morphology, tight junction integrity, ciliated and mucus-producing cells, and effective barrier function. Functional MCC was observed, confirming the model's potential for standardized clearance assays. Conclusions: This differentiated in vitro model closely replicates the structural and functional characteristics of in vivo airways. It provides a valuable platform for studying mucociliary clearance, toxicology, drug uptake, and evaluating mucosal formulations and dosage forms in respiratory research.

Compound screening in human airway basal cells identifies Wnt pathway activators as potential pro-regenerative therapies

Regeneration of the airway epithelium restores barrier function and mucociliary clearance following lung injury and infection. The mechanisms regulating the proliferation and differentiation of tissue-resident airway basal stem cells remain incompletely understood. To identify compounds that promote human airway basal cell proliferation, we performed phenotype-based compound screening of 1429 compounds (from the ENZO and Prestwick Chemical libraries) in 384-well format using primary cells transduced with lentiviral luciferase. A total of 17 pro-proliferative compounds were validated in independent donor cell cultures, including the antiretroviral therapy agent abacavir and several Wnt signalling pathway-activating compounds. The effects of compounds on proliferation were further explored in colony formation and 3D organoid assays. Structurally and functionally related compounds that more potently induced Wnt pathway activation were investigated. One such compound, 1-azakenpaullone, induced Wnt target gene activation and basal cell proliferation in mice. Our results demonstrate the pro-proliferative effect of small-molecule Wnt pathway activators on airway basal cells. These findings contribute to the rationale to develop novel approaches to modulate Wnt signalling during airway epithelial repair.

Assessment of liquid media requirements for storing and evaluating respiratory cilia motility

Mucociliary clearance is critical for maintaining normal lung function. Respiratory cilia which drive mucociliary clearance are commonly studied by measuring cilia beat frequency (CBF). There is currently significant variation within the literature regarding what is a normal value for CBF, this may be due in part to the large variety of liquid media used to suspend, maintain, and image ciliated cells. This study aimed to conduct a thorough examination to assess how media choice influences respiratory cilia motility. To accomplish this, Adult C57/BL6 mouse trachea samples were incubated in eight commonly used liquid media including: Saline, Dulbecco's Phosphate-Buffered Saline (DPBS), Hanks' Balanced Salt Solution (HBSS), Medium 199 (M199), Dulbecco's Modified Eagle's Medium (DMEM), Roswell Park Memorial Institute Medium (RPMI), Minimum Essential Medium (MEM), and Leibovitz's L-15 Medium (L-15); with or without 10% FBS supplementation. The effects of storage time (0-12 hours) and storage temperature (4 °C or room temperature) were also assessed. All media except saline were found to be equally effective in maintaining cilia function in airway samples that were freshly harvested and immediately imaged. Saline, however, significantly reduced the number of cells with motile cilia. A more complex pattern emerged when samples were stored before imaging. In saline, cilia function was significantly impaired after just one hour of storage. Samples stored in all other media showed strong maintenance of motile cilia function, with only minor changes. Notably, cilia function was better preserved with storage at 4 °C, while room temperature storage generally led to significant increases in CBF, especially in media containing FBS. Lastly, FBS supplementation was essential for maintaining cilia motility in L-15 media, as L-15 without FBS resulted in significant decreases in cilia motility following storage at either 4 °C or room temperature. In conclusion, saline should only be used if cilia are to be imaged immediately, as cilia stored in saline quickly lose motile function. All other commonly used media appear equally capable of maintaining motile cilia function for up to 12 hours when stored at 4 °C. Surprisingly, DPBS was just as effective as more expensive media in preserving ciliated samples. Storing ciliated tissue at room temperature generally leads to increased CBF, particularly in media containing FBS. Finally, L-15 media alone specifically requires the addition of 10% FBS to maintain cilia motility. These findings provide a valuable foundation for standardizing the handling, collection, and transport of ciliated samples for motile cilia assessment.

Air pollution and its impact on cancer incidence, cancer care and cancer outcomes

Air pollution is an under-recognised global health threat linked to an increased risk of cancers and is due primarily to the burning of fossil fuels. This review provides a high-level overview of the associations between outdoor and indoor air pollution and cancer risk and outcomes. Outdoor air pollutants are largely due to the burning of fossil fuels from human activities, although there is growing data implicating outdoor pollution from wildfire smoke. Indoor air pollution is primarily caused by burning solid fuel sources such as wood, coal and charcoal for household cooking and heating. There is a growing number of pieces of evidence linking exposure to pollution and the risk of developing cancers. The strongest evidence is seen on the positive association of air pollution, particularly particulate matter 2.5 with lung cancer. Emerging data implicate exposure to pollutants in the development of breast, gastrointestinal and other cancers. The mechanisms underlying these associations include oxidative stress, inflammation and direct DNA damage facilitated by pollutant absorption and distribution in the body. References were identified through a PubMed search for articles published in 2000 to October 2024 using the terms 'air pollution' or 'pollutants' and 'carcinoma' or ''cancer'. Air pollution poses significant risks to health. Its health impacts, including cancer risks, are often underestimated. Hazardous pollutants have been studied in several epidemiological cohort studies. Despite the mounting evidence, air pollution is often overlooked in predictive cancer risk models and public health intervention.

Development of a 3D bioengineered human lung submucosal gland ductal airway model to study mucociliary clearance in vitro

Mucociliary clearance (MCC) is critical in maintaining lung health and preventing respiratory infections. MCC is impaired in people with cystic fibrosis, due to accumulation of thick, sticky mucus resulting from defective cystic fibrosis transmembrane conductance regulator channel function. In this study, we developed a unique 3D lung submucosal gland ductal airway model utilizing primary human submucosal gland epithelial cells, which enables the formation of physiologically relevant architecture of the ductal epithelium including ciliary cells within a 3D bioprinted scaffold. Our observation demonstrates that this model not only enables the fabrication of human lung submucosal gland ductal airway-like structure mimicking in vivo physiology, also facilitates quantitative measurement of patient-specific MCC and determines pharmacological effects. Our results suggest that this model could be a valuable tool for understanding mechanisms underlying impaired MCC and testing the efficacy of novel therapeutic strategies for the treatment of respiratory diseases such as cystic fibrosis.

Modulation of pulmonary immune functions by the Pseudomonas aeruginosa secondary metabolite pyocyanin

Pseudomonas aeruginosa is a prevalent opportunistic Gram-negative bacterial pathogen. One of its key virulence factors is pyocyanin, a redox-active phenazine secondary metabolite that plays a crucial role in the establishment and persistence of chronic infections. This review provides a synopsis of the mechanisms through which pyocyanin exacerbates pulmonary infections. Pyocyanin induces oxidative stress by generating reactive oxygen and nitrogen species which disrupt essential defense mechanisms in respiratory epithelium. Pyocyanin increases airway barrier permeability and facilitates bacterial invasion. Pyocyanin also impairs mucociliary clearance by damaging ciliary function, resulting in mucus accumulation and airway obstruction. Furthermore, it modulates immune responses by promoting the production of pro-inflammatory cytokines, accelerating neutrophil apoptosis, and inducing excessive neutrophil extracellular trap formation, which exacerbates lung tissue damage. Additionally, pyocyanin disrupts macrophage phagocytic function, hindering the clearance of apoptotic cells and perpetuating inflammation. It also triggers mucus hypersecretion by inactivating the transcription factor FOXA2 and enhancing the IL-4/IL-13-STAT6 and EGFR-AKT/ERK1/2 signaling pathways, leading to goblet cell metaplasia and increased mucin production. Insights into the role of pyocyanin in P. aeruginosa infections may reveal potential therapeutic strategies to alleviate the severity of infections in chronic respiratory diseases including cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD).

Optical Imaging of Cilia in the Head and Neck

Background/Objectives: Cilia are hair-like organelles with various mechanosensory and chemosensory functions. In particular, motile cilia generate directional fluid flow important for multiple processes. Motile ciliopathies have serious clinical implications, including developmental and respiratory disorders. Evaluating the most suitable imaging methods for studying ciliary structure and function has great clinical significance. Methods: Here, we provide an overview of ciliary function, imaging modalities, and applications in ciliopathic diseases. Results: Optical imaging has become a crucial tool for studying ciliary structure and function, providing high-resolution, non-invasive imaging capabilities that are valuable for in vivo applications. Optical coherence tomography (OCT) is well suited for the visualization of ciliary anatomy and quantitative studies of microfluidic flow. Conclusions: A deeper understanding of ciliary biology can lead to novel approaches in diagnosing, treating, and monitoring ciliopathies, contributing to more effective and individualized care.

Structure and function relationships of mucociliary clearance in human and rat airways

Mucociliary clearance is a vital defense mechanism of the human airways, protecting against harmful particles and infections. When this process fails, it contributes to respiratory diseases like chronic obstructive pulmonary disease (COPD) and asthma. While advances in single-cell transcriptomics have revealed the complexity of airway composition, much of what we know about how airway structure impacts clearance relies on animal studies. This limits our ability to create accurate human-based models of airway diseases. Here we show that the airways in female rats and in humans exhibit species-specific differences in the distribution of ciliated and secretory cells as well as in ciliary beat, resulting in significantly higher clearance effectiveness in humans. We further reveal that standard lab-grown cultures exhibit lower clearance effectiveness compared to human airways, and we identify the underlying structural differences. By combining diverse experiments and physics-based modeling, we establish universal benchmarks to assess human airway function, interpret preclinical models, and better understand disease-specific impairments in mucociliary clearance.

The (re)emergence of aerosol delivery: Treatment of pulmonary diseases and its clinical challenges

Aerosol delivery represents a rapid and non-invasive way to directly reach the lungs while escaping the hepatic first-pass effect. The development of pulmonary drugs for respiratory diseases such as cystic fibrosis, lung infections, pulmonary fibrosis or lung cancer requires an enhanced understanding of the relationships between the natural physiology of the respiratory system and the pathophysiology of these conditions. This knowledge is crucial to better predict and thereby control drug deposition. Moreover, aerosol administration faces several challenges, including the pulmonary tract, immune system, mucociliary clearance, the presence of fluid on the airway surfaces, and, in some cases, bacterial colonisation. Each of them directly influences on the bioavailability of the active molecule. In addition to these challenges, particle size and the device used to administer the treatment are critical factors that can significantly impact the biodistribution of the drugs. Nanoparticles are very promising in the development of new formulations for aerosol drug delivery, as they can be fine-tuned to reach the entire pulmonary tract and overcome the difficulties encountered along the way. However, to properly assess drug delivery, preclinical studies need to be more thorough to efficiently enhance drug delivery.

Mucociliary cell type compositions - bridging the gap between genes and emergent tissue functions

When multiple cell types are brought together to form a tissue-specific collective, the combination of cell functions and cell-cell interactions leads to novel behaviors and properties beyond the simple addition of individual features, often referred to as emergent tissue functions. During evolution, functional adaptations in organs are significantly influenced by changes in cell type compositions, and in diseases, aberrations in cell type compositions result in impaired organ functions. Investigating the mechanisms that regulate cell type compositions could elucidate an important organizational meta-level that bridges gene functions and cellular features de facto facilitating the emergence of collective cell behaviors and novel tissue functions. Due to their unique evolutionary positioning and diverse functions, mucociliary epithelia could provide an optimal system to unravel principle mechanisms of adaptations in cell type compositions that facilitate the evolution of new or optimization of existing tissue functions, and could reveal novel entry points to counteract human diseases. An integrative investigation of signaling, transcriptional, epigenetic and morphogenetic mechanisms across a broad range of mucociliary tissues with different specialized cells and cell type compositions can help us to connect gene functions and contributions to self-organized behaviors in cell collectives determining emergent tissue functions. Taking such route moving forward has the potential to unravel novel principles in mucociliary self-organization and to reveal broadly applicable principles underlying the generation and modification of emergent tissue functions across species and organ systems.

Nano Approaches to Nucleic Acid Delivery: Barriers, Solutions, and Current Landscape

Nucleic acid (NA) therapy holds tremendous potential for treating a wide range of genetic diseases by the delivery of therapeutic genes into target cells. However, significant challenges exist in safely and effectively delivering these genes to their intended locations. Viral vectors, though efficient, pose risks such as immunogenicity and mutagenesis. This has resulted in growing interest in non-viral, nanoparticle-based NA delivery systems. This review article describes various physiological barriers to NA delivery and explores nanoparticle-based NA delivery systems, including bioengineered nanoparticles, peptides, lipid nanoparticles, and polymeric nanoparticles, highlighting their unique features to overcome in vivo barriers for NA delivery. While these nanoparticle-based NA delivery systems offer a promising alternative to viral vectors, challenges related to cytotoxicity, reproducible synthesis, and cost need to be addressed. The current clinical landscape of NA delivery is also discussed, emphasizing the need for safer, scalable, and cost-effective solutions. Nanoparticles represent a promising future in NA therapy, with the possibility of developing clinically relevant, non-toxic, stable, and non-immunogenic delivery vehicles, paving the way for broader therapeutic applications and improved clinical outcomes.

The Therapeutic Potential of Myo-Inositol in Managing Patients with Respiratory Diseases

Respiratory diseases are major health concerns worldwide. Chronic respiratory diseases (CRDs) are the third leading cause of death worldwide and some of the most common are chronic obstructive pulmonary disease (COPD), asthma, occupational lung diseases, and pulmonary hypertension. Despite having different etiology and characteristics, these diseases share several features, such as a persistent inflammatory state, chronic oxidative stress, impaired mucociliary clearance, and increased alveolar surface tension. CRDs are not curable; however, various forms of treatment, that help restore airway patency and reduce shortness of breath, can improve daily life for people living with these conditions. In this regard myo-inositol may represent a valid therapeutic adjuvant approach due to its properties. Being a redox balancer, an inflammation modulator, and, most importantly, a component of pulmonary surfactant, it may improve lung function and counteract symptoms associated with respiratory diseases, as recently evidenced in patients with COPD, COVID-19, asthma, and bronchiectasis. The aim of this review is to evaluate the potential therapeutic role of myo-inositol supplementation in the management of patients with respiratory diseases.

AggreBots: configuring CiliaBots through guided, modular tissue aggregation

Ciliated biobots, or CiliaBots, are a class of engineered multicellular tissues that are capable of self-actuated motility propelled by the motile cilia located on their exterior surface. Correlations have been observed between CiliaBot motility patterns and their morphology and cilia distribution. However, precise control of these structural parameters to generate desired motility patterns predictably remains lacking. Here, we developed a novel Aggregated CiliaBot (AggreBot) platform capable of producing designer motility patterns through spatially controlled aggregation of epithelial spheroids made from human airway cells (referred to as CiliaBot Building Blocks or CBBs), yielding AggreBots with configurable geometry and distribution of active cilia. Guided multi-CBB aggregation led to the production of rod-, triangle-, and diamond-shaped AggreBots, which consistently effected greater motility than traditional single-spheroid CiliaBots. Furthermore, CBBs were found to maintain internal boundaries post-aggregation through the combined action of pathways controlling cellular fluidity and tissue polarity. This boundary fidelity, combined with the use of CBBs with immotile cilia due to mutations in the CCDC39 gene, allowed for the generation of hybrid AggreBots with precision control over the coverage and distribution of active cilia, further empowering control of motility patterns. Our results demonstrate the potential of AggreBots as self-propelling biological tissues through the establishment of morphological "levers" by which alterations to tissue motility can be theoretically planned and experimentally verified.

Physiology and pathophysiology of mucus and mucolytic use in critically ill patients

Airway mucus is a highly specialised secretory fluid which functions as a physical and immunological barrier to pathogens whilst lubricating the airways and humifying atmospheric air. Dysfunction is common during critical illness and is characterised by changes in production rate, chemical composition, physical properties, and inflammatory phenotype. Mucociliary clearance, which is determined in part by mucus characteristics and in part by ciliary function, is also dysfunctional in critical illness via disease related and iatrogenic mechanisms. The consequences of mucus dysfunction are potentially devastating, contributing to prolonged ventilator dependency, increased risk of secondary pneumonia, and worsened lung injury. Mucolytic therapies are designed to decrease viscosity, improve expectoration/suctioning, and thereby promote mucus removal. Mucolytics, including hypertonic saline, dornase alfa/rhDNase, nebulised heparin, carbocisteine/N-Acetyl cysteine, are commonly used in critically ill patients. This review summarises the physiology and pathophysiology of mucus and the existing evidence for the use of mucolytics in critically ill patients and speculates on journey to individualised mucolytic therapy.

Comparison of air-liquid interface transwell and airway organoid models for human respiratory virus infection studies

Introduction

Complex in vitro respiratory models, including air-liquid interface (ALI) transwell cultures and airway organoids, have emerged as promising tools for studying human respiratory virus infections. These models address several limitations of conventional two-dimensional cell line and animal models. However, the lack of standardized protocols for the application of these models in infection studies limits the possibilities for comparing results across different research groups. Therefore, we applied a collaborative approach to harmonize several aspects of experimental methodology between different research laboratories, aiming to assess the comparability of different models of human airway epithelium in the context of respiratory viral infections.

Methods

In this study, we compared three different models of human respiratory epithelium: a primary human bronchial epithelial cell-derived ALI transwell model, and two airway organoid models established from human airway- and lung-derived adult stem cells. We first assessed the presence of various differentiated cell types using immunofluorescence microscopy. Using a shared stock of influenza A virus, we then assessed viral growth kinetics, epithelial cytokine responses, and serum-mediated inhibition of infection.

Results

The presence of club, goblet, and ciliated cells was confirmed in all models. We observed similar viral replication kinetics with a >4-log increase in virus titre across all models using a TCID50 assay. Following infection, a reproducible antiviral cytokine response, including a consistent increase in CXCL10, IL-6, IFN-λ1, IFN-λ2/3, and IFN-β, was detected across all models. Finally, neutralization was assessed by pre-incubation of virus with human serum. Reduced viral replication was observed across all models, resulting in a 3- to 6-log decrease in virus titres as quantified by TCID50.

Discussion

In conclusion, all three models produced consistent results regardless of the varying cell sources, culturing approaches, and infection methods. Our collaborative efforts to harmonize infection experiments and compare ALI transwell and airway organoid models described here aid in advancing our understanding and improving the standardization of these complex in vitro respiratory models for future studies.

The Effect of Laryngeal Dehydration and Nebulized Osmotic Agents on the Voice

OBJECTIVE

This study investigates the effects of dehydration induced by dry air breathing and the nebulization of various osmotic agents on vocal parameters, including perceptual, acoustic, and electroglottographic measures.

METHODS

Thirty normophonic females (age x̅ = 26, SD = 1.67) participated over three consecutive days. On the first day, the baseline data were meticulously collected before the participants underwent a 22-minute session of transoral dry air breathing. Immediately after this desiccation protocol, measurements were taken to establish the initial effects. Subsequently, one of three osmotic agents was randomly selected for each participant. These agents included hypotonic distilled water, 0.9% isotonic saline, and 3% hypertonic saline. Each participant then underwent a 10-minute nebulization session with 5 mL of the assigned osmotic agent. The process was repeated on the second and third days. Each day, the participants again experienced the 22-minute transoral dry air breathing session. The evaluations were performed by Borg CR-10 (perceived vocal effort), electroglottography (EGG), voice onset time (VOT), nasalance score (NS), and cepstral peak prominence analyses with CAPE-V sentences (s).

RESULTS

No statistically significant differences were found in the EGG parameters between the preliminary recordings, post transoral medical-grade dry air protocol, and after each of task-hypotonic, task-isotonic, and task-hypertonic. Following the transoral medical-grade dry air protocol, both /s1/-CPP and /s5/-CPP values decreased compared with the preliminary recordings. Only /s1/-CPP values increased after the 0.9% isotonic saline nebulization. NS from preliminary measurements was higher for both oronasal and nasal texts compared with scores after the dry air protocol and nebulization. Voiceless plosive VOT values decreased solely after the 0.9% isotonic saline nebulization. Participants' Borg CR-10 scores increased after transoral medical-grade dry air protocol and decreased after nebulization with distilled water and 0.9% isotonic saline.

CONCLUSIONS

Isotonic saline and distilled water nebulization protocols demonstrated a trend toward mitigating the adverse effects of the transoral medical-grade dry air inhalation protocol on vocal parameters.

Enhanced Macrophage Uptake of Spray-Dried Phosphatidylserine-Loaded Microparticles for Pulmonary Drug Delivery Applications

Macrophages are an integral part of the innate immune system and act as a first line of defense to pathogens; however, macrophages can be reservoirs for pathogens to hide and replicate. Tuberculosis, influenza virus, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are common diseases whose pathogens are uptaken into macrophages. Current treatments for diseases such as these are limited by the therapeutic delivery method, which typically involves systemic delivery in large, frequent doses. This study aims to overcome this limitation via the development of an inhalable dry powder microparticle (MP) formulation capable of targeted drug delivery to alveolar macrophages in addition to controlled release of a therapeutic. A simple one-step spray drying method was used to synthesize acetalated dextran (Ac-Dex) MP loaded with the model therapeutic, curcumin, and 1,2-dipalmitoyl-sn-glycero-3-phospho-L-serine (DPPS), which is a phospholipid that induces ligand-receptor mediated macrophage phagocytosis. The resulting MP exhibited significantly more uptake by RAW 264.7 macrophages in comparison to MP without DPPS, and it was shown that DPPS-mediated uptake was macrophage specific. The particles exhibited pH-responsive release and in vitro aerosol dispersion analysis confirmed the MP can be effectively aerosolized for pulmonary delivery. Overall, the described MP has the potential to improve treatment efficacy for macrophage-associated diseases.

Epithelial and immune transcriptomic characteristics and possible regulatory mechanisms in asthma exacerbation: insights from integrated studies

Background

Asthma exacerbation significantly contribute to disease mortality and result in heightened health care expenditures. This study was aimed at gaining important new insights into the heterogeneity of epithelial and immune cells and elucidating key regulatory genes involved in the pathogenesis of asthma exacerbation.

Methods

Functional enrichment, pseudotime, metabolism and cell-cell communication analyses of epithelial cells and immune cells in single-cell RNA sequencing (scRNA-seq) dataset were applied. Immune infiltration analysis was performed in bulk RNA sequencing (bulk RNA-seq) dataset. Key regulatory genes were obtained by taking the intersection of the differentially expressed genes (DEGs) between control and asthma group in epithelial cells, immune cells and bulk RNA-seq data. Asthma animal and in vitro cell line models were established to verify the key regulatory genes expression by employing quantitative reverse transcription polymerase chain reaction (qRT-PCR).

Results

ScRNA-seq analysis identified 7 epithelial subpopulations and 14 distinct immune cell types based on gene expression profiles. Further analysis demonstrated that these cells manifested high heterogeneity at the levels of functional variations, dynamics, communication patterns and metabolic changes. Notably, TMPRSS11A, TUBA1A, SCEL, ICAM4, TMPRSS11B, IGFBP2, CLC, NFAM1 and F13A1 were identified as key regulatory genes of asthma. The results of the qRT-PCR demonstrated that the 9 key regulatory genes were involved in asthma.

Conclusions

We systematically explored epithelial and immune characteristics in asthma exacerbation and identified 9 key regulatory genes underlying asthma occurrence and progression, which may be valuable for providing new insights into the cellular and molecular mechanisms driving asthma exacerbations.

Inhalable Mucociliary-On-Chip System Revealing Pulmonary Clearance Dynamics in Nanodrug Delivery

The development of a inhaled nanodrug delivery assessment platform is crucial for advancing treatments for chronic lung diseases. Traditional in vitro models and commercial aerosol systems fail to accurately simulate the complex human respiratory patterns and mucosal barriers. To address this, we have developed the breathing mucociliary-on-a-chip (BMC) platform, which replicates mucociliary clearance and respiratory dynamics in vitro. This platform allows for precise analysis of drug deposition and penetration, providing critical insights into how liposomes and other nanocarriers interact with lung tissues under various airflow conditions. Our results reveal that liposomes penetrate deeper into the cellular layer under high shear stress, with both static and dynamic airflows distinctly affecting their drug release rates. The BMC platform integrates dynamic inhalation systems with mucociliary clearance functionality, enabling a comprehensive evaluation of drug delivery efficacy. This approach highlights the importance of airflow dynamics in optimizing inhalable nanodrug delivery systems, improving nanocarrier design, and tailoring drug dosages and release strategies. The BMC platform represents a significant advancement in the field of inhaled nanodrug delivery, offering a more accurate and reliable method for assessing the performance of therapies. By providing a detailed understanding of drug interactions with lung tissues, this platform supports the development of personalized inhaled therapies and offers promising strategies for treating pulmonary diseases and advancing nanodrug development.

A 3D Model of the Human Lung Airway for Evaluating Permeability of Inhaled Drugs

Current in vitro cell-based methods, relying on single cell types, have structural and functional limitations in determining lung drug permeability, which is a contributing factor affecting both local and systemic drug levels. To address this issue, we investigated a 3D human lung airway model generated using a cell culture insert, wherein primary human lung epithelial and endothelial cells were cocultured at an air-liquid interface (ALI). To ensure that the cell culture mimics the physiological and functional characteristics of airway tissue, the model was characterized by evaluating several parameters such as cellular confluency, ciliation, tight junctions, mucus-layer formation, transepithelial electrical resistance, and barrier function through assaying fluorescein isothiocyanate-dextran permeability. To understand how the characterized ALI quality attributes influenced the absorption of inhaled drugs through the epithelial-endothelial barrier, we measured the permeability and epithelial intracellular concentrations of albuterol sulfate (AL), formoterol fumarate (FO), and fluticasone furoate (FL). The presented characterization results overall demonstrate that this culture platform mimicked the airway-specific structure and barrier function. An apparent permeability (P app) of 5.7 × 10-6 cm/s and an intracellular concentration below 1% were quantified for AL over 3 h. The P app of FO was 8.5 × 10-6 cm/s, with an intracellular concentration of 3.8%. Due to its high lipophilicity, FL showed a higher intracellular concentration (17.4%) compared to AL and FO, but also a 73.1% loss of the compound over 3 h due to nonspecific binding, with a P app as low as 1.3 × 10-7 cm/s. While the model exhibited physiologically relevant properties, its utility in estimating the permeability of inhaled drugs may be drug-specific, warranting further optimization and study.

Mucosal immune response in biology, disease prevention and treatment

The mucosal immune system, as the most extensive peripheral immune network, serves as the frontline defense against a myriad of microbial and dietary antigens. It is crucial in preventing pathogen invasion and establishing immune tolerance. A comprehensive understanding of mucosal immunity is essential for developing treatments that can effectively target diseases at their entry points, thereby minimizing the overall impact on the body. Despite its importance, our knowledge of mucosal immunity remains incomplete, necessitating further research. The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has underscored the critical role of mucosal immunity in disease prevention and treatment. This systematic review focuses on the dynamic interactions between mucosa-associated lymphoid structures and related diseases. We delve into the basic structures and functions of these lymphoid tissues during disease processes and explore the intricate regulatory networks and mechanisms involved. Additionally, we summarize novel therapies and clinical research advances in the prevention of mucosal immunity-related diseases. The review also addresses the challenges in developing mucosal vaccines, which aim to induce specific immune responses while maintaining tolerance to non-pathogenic microbes. Innovative therapies, such as nanoparticle vaccines and inhalable antibodies, show promise in enhancing mucosal immunity and offer potential for improved disease prevention and treatment.

Pseudomonas aeruginosa pqs Quorum Sensing Mediates Interaction with Mycobacterium abscessus In Vitro

Pseudomonas aeruginosa and Mycobacterium abscessus are opportunistic pathogens that cause severe infections in hospitals, and their co-infections are increasingly reported. The interspecies interactions between these two bacterial species and their potential impacts on infections are largely unexplored. In this study, we first demonstrated that P. aeruginosa inhibits the growth of M. abscessus by iron chelating via pqs quorum sensing. Next, through proteomic analysis, we discovered that the PQS molecule significantly changed a large amount of protein expression in M. abscessus, including proteins involved in the type VII secretion system and iron homeostasis. Furthermore, we revealed that PQS significantly enhanced the production of bacterial membrane vesicles (MVs) by M. abscessus. Our study suggests that the P. aeruginosa PQS can serve as an interspecies signaling molecule to communicate with Mycobacterium and affect their physiology and virulence.

A clinical comparative study of an outpatient treatment group and an endoscopic sinus surgery group for maxillary sinus fungus ball

PURPOSE

This study aimed to clarify the differences in the pathophysiology of maxillary sinus fungus balls (FB) among different case groups and to identify which patients with maxillary sinus FB would be suitable for outpatient procedures.

METHODS

Thirty-four patients diagnosed with maxillary sinus FB between January 2017 and December 2021 were divided into two groups (O and S). We retrospectively compared the clinical and imaging characteristics, and the treatment outcomes between the groups. Group O comprised 12 patients (13 sides) treated in an outpatient clinic and Group S comprised 15 patients (16 sides) treated with endoscopic sinus surgery (ESS).

RESULTS

Compared to Group S, Group O had more patients with an enlarged maxillary sinus membranous portion, and shadows indicative of fungal masses (P < 0.01 and P < 0.05, respectively). In particular, the anteroposterior ratio of the open maxillary sinus membranous area was 0.68 ± 0.16 in Group O and 0.5 ± 0.12 in Group S. After surgery, Group O exhibited greater anteroposterior expansion of the maxillary sinus membranous portion compared to Group S (P < 0.01). Additionally, Group O had more patients with shadows in sinuses other than the maxillary sinus (P < 0.01) and medial displacement of the uncinate process (P < 0.01) than Group S. In addition, Group O required fewer procedures and hospital visits than Group S (P < 0.001 and P < 0.01, respectively).

CONCLUSIONS

Determining the indications for outpatient procedures while considering the pathophysiology of maxillary sinus FB can significantly benefit patients and medical professionals in terms of safety and medical costs.

Incidence, risk factors, and epidemiological trends of tracheal cancer: a global analysis

BACKGROUND

Tracheal cancer is a rare malignancy with limited research but high mortality rates. This study aims to analyse recent data to understand the global burden, trends, and risk factors for tracheal cancer, facilitating improved prevention and treatment strategies.

METHODS

We conducted a study on tracheal cancer using data from the Global Cancer Observatory and the Cancer Incidence in Five Continents databases. We collected information on the incidence of tracheal cancer, risk factors, and the Human Development Index (HDI) at the country level. The univariate linear regression was used to explore the relationship between tracheal cancer and the various risk factors. We utilised joinpoint regression analysis to calculate the Average Annual Percentage Change (AAPC) in tracheal cancer incidence.

RESULTS

The global age-standardised rate of incidence of tracheal cancer was 2.9 per 10 million (3,472 cases in total) in 2022, with the highest regional incidence observed in Central and Eastern Europe (ASR = 9.0) and the highest national incidence in Hungary (12.5). Higher incidence was found among the males (3.8) than females (2.0); among the older adults aged 50-74 (11.9) than the younger population aged 15-49 (1.2). A higher tracheal cancer incidence ratio was associated with higher levels of smoking, alcohol drinking, diabetes, lipid disorders, and HDI. Despite the overall decreasing trends for all population groups (highest decrease in Thailand; AAPC: -15.06, 95% CI: -21.76 to -7.78, p = 0.002), there was an increase in some female populations (highest increase in Colombia, AAPC: 19.28, 95% CI: 16.48 to 22.15, p < 0.001) and younger populations (highest increase in Ireland; AAPC: 29.84, 95% CI: 25.74 to 34.06, p < 0.001).

CONCLUSION

This study provides a comprehensive analysis of tracheal cancer, focusing on risk factors and population-level trends. There has been an overall decreasing trend in the incidence of tracheal cancer, particularly among males and older adults, while the decline is less pronounced in females and younger individuals. Further research is needed to explore the underlying drivers of these epidemiological trends.

Protective effect of interferon type I on barrier function of human airway epithelium during rhinovirus infections in vitro

The airway epithelium provides a crucial barrier against infection with respiratory pathogens. This barrier can be impaired following viral infection, paving the way for bacterial superinfections. Type I interferons (IFNs) are important antiviral mediators, and inhaled formulations of these glycoproteins are considered a potential approach for the treatment of respiratory viral infections. To investigate if type I IFNs can also protect against virus-induced epithelial barrier dysfunction, differentiated primary bronchial epithelial cells were pre-treated with IFN-β1a and subsequently infected with human rhinovirus (HRV) for 24 to 72h. Moreover, to functionally assess the effects of IFN-β1a pre-treatment on barrier integrity, we conducted co-infection experiments, in which cells were initially infected with HRV, and superinfected with Streptococcus pneumoniae 24 to 72 h later. In untreated cells, HRV infection significantly damaged ZO-1 positive tight junctions and cilia, and transiently increased permeability, whereas the barrier of cultures pre-treated with IFN-β1a remained intact. In co-infection experiments, bacteria were able to penetrate deeper into the cell layers of HRV-infected cultures than into those of uninfected cells. IFN-β1a pre-treatment abrogated virus-induced damage to the epithelial barrier. Taken together, these data demonstrate a beneficial effect of IFN-β in protecting epithelial barrier function in addition to its antiviral effects.

Kinetics and Optimality of Influenza A Virus Locomotion

Influenza A viruses (IAVs) must navigate through a dense extracellular mucus to infect airway epithelial cells. The mucous layer, composed of glycosylated biopolymers (mucins), presents sialic acid that binds to ligands on the viral envelope and can be irreversibly cleaved by viral enzymes. It was recently discovered that filamentous IAVs exhibit directed persistent motion along their long axis on sialic acid-coated surfaces. This Letter demonstrates through stochastic simulations and mean-field theory, how IAVs harness a "burnt-bridge" Brownian ratchet mechanism for directed persistent translational motion. Importantly, our analysis reveals that equilibrium features of the system primarily control the dynamics, even out of equilibrium, and that asymmetric distribution of ligands on the virus allows for more robust directed transport. We show viruses occupy the optimal parameter range ("Goldilocks zone") for efficient mucous transport, possibly due to the evolutionary adaptation of enzyme kinetics. Our findings suggest novel therapeutic targets and provide insight into possible mechanisms of zoonotic transmission.

HIV-1 Tat Protein and Cigarette Smoke Mediated ADAM17 Upregulation Can Lead to Impaired Mucociliary Clearance

Human immunodeficiency virus type-1 (HIV-1) associated comorbidities account for the majority of poor health outcomes in people living with HIV (PLWH) in the era of antiretroviral therapy. Lung-related comorbidities such as chronic obstructive pulmonary disease (COPD) and bacterial pneumonia are primarily responsible for increased morbidity and mortality in PLWH, even when compensated for smoking. Smokers and COPD patients demonstrate cilia shortening, attenuated ciliary beat frequency (CBF), dysfunctional ciliated cells along with goblet cell hyperplasia, and mucus hypersecretion. This is exacerbated by the fact that almost 60% of PLWH smoke tobacco, which can exacerbate inflammation and mucociliary clearance (MCC) dysfunction. This study shows that HIV Tat alters the microRNAome in airway epithelial cells and upregulates miR-34a-5p with consequent suppression of its target, Sirtuin 1 (SIRT1). SIRT1 is known to suppress Metalloproteinase 17 (ADAM17), a protease activating Notch signaling. HIV and cigarette smoke (CS) upregulate ADAM17. ADAM17 upregulation followed by SIRT1 suppression can lead to decreased ciliation, mucus hypersecretion, and attenuated MCC, a hallmark of chronic bronchitis in smokers and COPD. It is, therefore, essential to understand the pathophysiological mechanism resulting in acquired Notch dysregulation and its downstream impact on HIV-infected smokers.

A nanotechnology driven effectual localized lung cancer targeting approaches using tyrosine kinases inhibitors: Recent progress, preclinical assessment, challenges, and future perspectives

The higher incidence and mortality rate among all populations worldwide explains the unmet solutions in the treatment of lung cancer. The evolution of targeted therapies using tyrosine kinase inhibitors (TKI) has encouraged anticancer therapies. However, on-target and off-target effects and the development of drug resistance limited the anticancer potential of such targeted biologics. The advances in nanotechnology-driven-TKI embedded carriers that offered a new path toward lung cancer treatment. It is the inhalation route of administration known for its specific, precise, and efficient drug delivery to the lungs. The development of numerous TKI-nanocarriers through inhalation is proof of TKI growth. The future scopes involve using potential lung cancer biomarkers to achieve localized active cancer-targeting strategies. The adequate knowledge of in vitro absorption models usually helps establish better in vitro - in vivo correlation/extrapolation (IVIVC/E) to successfully evaluate inhalable drugs and drug products. The advanced in vitro and ex vivo lung tissue/ organ models offered better tumor heterogeneity, etiology, and microenvironment heterogeneity. The involvement of lung cancer organoids (LCOs), human organ chip models, and genetically modified mouse models (GEMMs) has resolved the challenges associated with conventional in vitro and in vivo models. To access potential inhalation-based drugtherapies, biological barriers, drug delivery, device-based challenges, and regulatory challenges must be encountered associated with their development. A proper understanding of material toxicity, size-based particle deposition at active disease sites, mucociliary clearance, phagocytosis, and the presence of enzymes and surfactants are required to achieve successful inhalational drug delivery (IDD). This article summarizes the future of lung cancer therapy using targeted drug-mediated inhalation using TKI.

Biopolymeric Inhalable Dry Powders for Pulmonary Drug Delivery

Natural and synthetic biopolymers are gaining popularity in the development of inhaled drug formulations. Their highly tunable properties and ability to sustain drug release allow for the incorporation of attributes not achieved in dry powder inhaler formulations composed only of micronized drugs, standard excipients, and/or carriers. There are multiple physiological barriers to the penetration of inhaled drugs to the epithelial surface, such as the periciliary layer mucus mesh, pulmonary macrophages, and inflammation and mucus compositional changes resulting from respiratory diseases. Biopolymers may facilitate transport to the epithelial surface despite such barriers. A variety of categories of biopolymers have been assessed for their potential in inhaled drug formulations throughout the research literature, ranging from natural biopolymers (e.g., chitosan, alginate, hyaluronic acid) to those synthesized in a laboratory setting (e.g., polycaprolactone, poly(lactic-co-glycolic acid)) with varying structures and compositions. To date, no biopolymers have been approved as a commercial dry powder inhaler product. However, advances may be possible in the treatment of respiratory diseases and infections upon further investigation and evaluation. Herein, this review will provide a thorough foundation of reported research utilizing biopolymers in dry powder inhaler formulations. Furthermore, insight and considerations for the future development of dry powder formulations will be proposed.

Ciliopathy organoid models: a comprehensive review

Cilia are membrane-bound organelles found on the surface of most mammalian cell types and play numerous roles in human physiology and development, including osmo- and mechanosensation, as well as signal transduction. Ciliopathies are a large group of, usually rare, genetic disorders resulting from abnormal ciliary structure or ciliary dysfunction that have a high collective prevalence. Autosomal dominant or recessive polycystic kidney disease (ADPKD/ARPKD), Bardet-Biedl-Syndrome, and primary ciliary dyskinesia (PCD) are the most frequent etiologies. Rodent and zebrafish models have improved the understanding of ciliopathy pathophysiology. Yet, the limitations of these genetically modified animal strains include the inability to fully replicate the phenotypic heterogeneity found in humans, including variable multiorgan involvement. Organoids, self-assembled three-dimensional cell-based models derived from human induced pluripotent stem cells (iPSCs) or primary tissues, can recapitulate certain aspects of the development, architecture, and function of the target organ "in the dish." The potential of organoids to model patient-specific genotype-phenotype correlations has increased their popularity in ciliopathy research and led to the first preclinical organoid-based ciliopathy drug screens. This review comprehensively summarizes and evaluates current ciliopathy organoid models, focusing on kidney, airway, liver, and retinal organoids, as well as the specific methodologies used for their cultivation and for interrogating ciliary dysfunction.

The impact of airborne particulate matter-based pollution on the cellular and molecular mechanisms in chronic obstructive pulmonary disease (COPD)

Inhalation of particulate matter (PM), one of the many components of air pollution, is associated with the development and exacerbation of chronic respiratory diseases, such as chronic obstructive pulmonary disease (COPD). COPD is one of the leading causes of global mortality and morbidity, with a paucity of therapeutic options and a significant contributor to global health expenditure. This review aims to provide a mechanistic understanding of the cellular and molecular pathways that lead to the development of COPD following chronic PM exposure. Our review describes how the inhalation of PM can lead to lung parenchymal destruction and cellular senescence due to chronic pulmonary inflammation and oxidative stress. Following inhalation of PM, significant increases in a range of pro-inflammatory cytokines, mediated by the nuclear factor kappa B pathway are reported. This review also highlights how the inhalation of PM can lead to deleterious chronic oxidative stress persisting in the lung post-exposure. Furthermore, our work summarises how PM inhalation can lead to airway remodelling, with increases in pro-fibrotic cytokines and collagen deposition, typical of COPD. This paper also accentuates the interconnection and possible synergism between the pathophysiological mechanisms leading to COPD. Our work emphasises the serious health consequences of PM exposure on respiratory health. Elucidation of the cellular and molecular mechanisms can provide insight into possible therapeutic options. Finally, this review should serve as a stark reminder of the need for genuine action on air pollution to decrease the associated health burden on our growing global population.

Characterization of a primary cellular airway model for inhalative drug delivery in comparison with the established permanent cell lines CaLu3 and RPMI 2650

Purpose

For optimization of respiratory drug delivery, the selection of suitable in vitro cell models plays an important role in predicting the efficacy and safety of (bio)pharmaceutics and pharmaceutical formulations. Therefore, an in-depth comparison of different primary and permanent in vitro cellular airway models was performed with a focus on selecting a suitable model for inhalative antibodies.

Methods

Primary cells isolated from the porcine trachea were compared with the established human cell lines CaLu3 and RPMI 2650. The in vitro models were characterized for different epithelial markers by real-time quantitative polymerase chain reaction, which provides insight into the cellular composition of each model. For a few selected markers, the results from RT-qPCR were confirmed via immunofluorescence. Barrier integrity was assessed by transepithelial electrical resistance measurements and FITC-dextran permeability.

Results

Primary cell models retain key features of the respiratory epithelium, e.g., the formation of a tight epithelial barrier, mucin production, and the presence of club/basal cells. Furthermore, the expression of Fc receptors in the primary cell models closely resembles that in respiratory mucosal tissue, an essential parameter to consider when developing therapeutic antibodies for inhalation.

Conclusion

The study underlines the importance of selecting wisely appropriate in vitro models. Despite the greater effort and variability in cultivating primary airway cells, they are far superior to permanent cells and a suitable model for drug development.

Supplementary Information

The online version contains supplementary material available at 10.1007/s44164-024-00079-y.

Aspiration after Critical Illness: Role of Endotracheal Tube, Tracheostomy, and Swallowing Disorders

Swallowing is a complex process that involves over 50 muscles and nerves and has two critical roles: passing food from the oral cavity through the pharynx and into the esophagus and preventing contents from entering the airway. If a patient's swallowing physiology or airway protective mechanisms are disturbed, the airways and the lungs have innate defense systems to protect against injury and infection. However, critically ill patients are more likely to develop dysphagia, which is an impairment or malfunction in any aspect of the swallowing mechanism, due to the numerous interventions they undergo. When airway reflexes fail, commonly in the presence of dysphagia, aspiration can occur, which is the entry of a fluid or solid below the level of the true vocal cords. If left unmanaged, dysphagia has been associated with aspiration pneumonia, pneumonitis, airway obstruction, delayed enteral nutrition, prolonged length of intensive care unit (ICU) and hospital stay, reduced quality of life, and even death; in some cases, dysphagia is an independent risk factor for mortality. It is important to routinely assess dysphagia in all critically ill patients using a multimodal approach, including systematic assessments, scoring indices, trained specialists, and ICU nurses. Several interventions are crucial for preventing and managing dysphagia and its associated problems. Further research is necessary to help determine the best ways to prevent and manage pulmonary aspiration in critically ill patients. Several interventions are essential in preventing and managing dysphagia and the sequelae of swallowing dysfunction. Further research is needed to help elucidate the best way to avoid and manage pulmonary aspiration in critically ill patients.

Local and systemic effects of microplastic particles through cell damage, release of chemicals and drugs, dysbiosis, and interference with the absorption of nutrients

Microplastic particles (MPs) have been detected in a variety of environmental samples, including soil, water, food, and air. Cellular studies and animal exposures reported that exposure to MPs composed of different polymers might result in adverse effects at the portal of entry (local) or throughout the body (systemic). The most relevant routes of particle uptake into the body are oral and respiratory exposure. This review describes the various processes that may contribute to the adverse effects of MPs. Only MPs up to 5 µm were found to cross epithelial barriers to a significant extent. However, MPs may also exert a detrimental impact on human health by acting at the epithelial barrier and within the lumen of the orogastrointestinal and respiratory tract. The potential for adverse effects on human health resulting from the leaching, sorption, and desorption of chemicals, as well as the impact of MPs on nutritional status and dysbiosis, are reviewed. In vitro models are suggested as a means of (1) assessing permeation, (2) determining adverse effects on cells of the epithelial barrier, (3) examining influence of digestive fluids on leaching, desorption, and particle properties, and (4) role of microbiota-epithelial cell interactions. The contribution of these mechanisms to human health depends upon exposure levels, which unfortunately have been estimated very differently.

Sensory artificial cilia for in situ monitoring of airway physiological properties

Continuously monitoring human airway conditions is crucial for timely interventions, especially when airway stents are implanted to alleviate central airway obstruction in lung cancer and other diseases. Mucus conditions, in particular, are important biomarkers for indicating inflammation and stent patency but remain challenging to monitor. Current methods, reliant on computational tomography imaging and bronchoscope inspection, pose risks due to radiation and lack the ability to provide continuous real-time feedback outside of hospitals. Inspired by the sensing ability of biological cilia, we report wireless sensing mechanisms in sensory artificial cilia for detecting mucus conditions, including viscosity and layer thickness, which are crucial biomarkers for disease severity. The sensing mechanism for mucus viscosity leverages external magnetic fields to actuate a magnetic artificial cilium and sense its shape using a flexible strain-gauge. Additionally, we report an artificial cilium with capacitance sensing for mucus layer thickness, offering unique self-calibration, adjustable sensitivity, and range, all enabled by external magnetic fields. To enable prolonged and wireless data access, we integrate Bluetooth Low Energy communication and onboard power, along with a wearable magnetic actuation system for sensor activation. We validate our method by deploying the sensor independently or in conjunction with an airway stent within a trachea phantom and sheep trachea ex vivo. The proposed sensing mechanisms and devices pave the way for real-time monitoring of mucus conditions, facilitating early disease detection and providing stent patency alerts, thereby allowing timely interventions and personalized care.

An in vitro study of the impact of IL-17A and IL-22 on ciliogenesis in nasal polyps epithelium via the Hippo-YAP pathway

BACKGROUND

Cilia loss and impaired motile ciliary functions are among the typical pathological features of chronic rhinosinusitis with nasal polyps (CRSwNP). IL17A and IL22 are the canonical cytokines of type 3 inflammation, exhibiting similar functional effects on epithelial cells. In this study, we sought to examine the effects of IL17A and IL22 on ciliated cells and investigate the potential involvement of Hippo-YAP signaling in their influence on ciliogenesis.

METHODS

We assessed both the mRNA and protein expression levels of IL17A and IL22 in nasal tissues obtained from patients with CRSwNP and compared them to those from healthy controls. To further explore the impact of IL17A and IL22, we established a primary human nasal epithelial cell model using different concentrations (2 ng/mL, 10 ng/mL, 50 ng/mL) for a duration of 28 days in an air-liquid interface culture. Additionally, we employed the inhibitor verteporfin to investigate whether IL17A and IL22 exert their effects on ciliated cells via the Hippo-YAP pathway.

RESULTS

The mRNA and protein levels of IL17A and IL22 in CRSwNP were significantly higher than those in healthy controls, revealing a robust correlation between IL17A and IL22. YAP was highly expressed in the nucleus of ciliated cells in CRSwNP and displayed a positive correlation with clinical symptoms. Both IL17A and IL22 were found to reduce the number of ciliated cells. IL17A, but not IL22, suppressed ciliogenesis by disrupting the proper development and docking of the basal body of ciliated cells, resulting in motile ciliary dysfunctions. Furthermore, the expression of YAP within the nucleus of ciliated cells gradually declined as these cells reached the final stage of differentiation. However, this process was obstructed by IL17A only. YAP inhibitors, such as verteporfin, markedly reversed the effects of IL17A by increasing the proportion of ciliated cells, suppressing nuclear YAP expression in these cells, and enhancing ciliary beating frequency.

CONCLUSIONS

Both IL17A and IL22 are overexpressed in nasal epithelium of CRSwNP, which is associated with the impairment of epithelial cell differentiation. Furthermore, IL17A has been shown to exert a disruptive effect on morphogenesis of motile cilia via activation of YAP.

Review of epidemiological and toxicological studies on health effects from ingestion of asbestos in drinking water

Asbestos is a group of naturally occurring fibrous minerals that were commonly used in the construction of cement pipes for drinking water distribution systems. These pipes deteriorate and can release asbestos fibers into drinking water, raising concerns about potential risk to human health. The objective of this work was to synthesize human, animal, and in vitro evidence on potential health risks due to ingested asbestos in drinking water and evaluate the weight of evidence (WoE) of human health risk. A systematic review of epidemiological evidence was conducted, along with critical review of animal and in vitro evidence, followed by WoE evaluation that integrated human, animal, and in vitro evidence. The systematic review included 17 human studies with health outcomes mostly related to various cancer sites, with the majority focusing on the gastrointestinal system. The WoE evaluation resulted in very low levels of confidence or insufficient evidence of a health effect for cancers in 15 organ systems and for three non-cancer endpoints. While eight studies reported possible associations with stomach cancer in males, few high-quality studies were available to verify a causal relationship. Based on high-quality animal studies, an increased risk for cancer or non-cancer endpoints was not supported, aligning with findings from human studies. Overall, the currently available body of evidence is insufficient to establish a clear link between asbestos contamination in drinking water and adverse health effects. Due to the lack of both high-quality epidemiological studies and a validated kinetic model for ingested asbestos, additional research on this association is warranted.