Human Lung Airway Research Articles

Photon-Counting Detector CT Radiological-Histological Correlation in Cadaveric Human Lung Nodules and Airways.

The aim of this study was to compare the performances of photon-counting detector computed tomography (PCD-CT) and energy-integrating detector computed tomography (EID-CT) for visualizing nodules and airways in human cadaveric lungs. Previously obtained 20 cadaveric lungs were scanned, and images were prospectively acquired by EID-CT and PCD-CT at a radiation dose with a noise level equivalent to the diagnostic reference level. PCD-CT was scanned with ultra-high-resolution mode. The EID-CT images were reconstructed with a 512 matrix, 0.6-mm thickness, and a 350-mm field of view (FOV). The PCD-CT images were reconstructed at 3 settings: PCD-512: same as EID-CT; PCD-1024-FOV350: 1024 matrix, 0.2-mm thickness, 350-mm FOV; and PCD-1024-FOV50: 1024 matrix, 0.2-mm thickness, 50-mm FOV. Two specimens per lung were examined after hematoxylin and eosin staining. The CT images were evaluated for nodules on a 5-point scale and for airways on a 4-point scale to compare the histology. The Wilcoxon signed rank test with Bonferroni correction was performed for statistical analyses. Sixty-seven nodules (1321 μm; interquartile range [IQR], 758-3105 μm) and 92 airways (851 μm; IQR, 514-1337 μm) were evaluated. For nodules and airways, scores decreased in order of PCD-1024-FOV50, PCD-1024-FOV350, PCD-512, and EID-CT. Significant differences were observed between series other than PCD-1024-FOV350 versus PCD-1024-FOV50 for nodules (PCD-1024-FOV350 vs PCD-1024-FOV50, P = 0.063; others P < 0.001) and between series other than EID-CT versus PCD-512 for airways (EID-CT vs PCD-512, P = 0.549; others P < 0.005). On PCD-1024-FOV50, the median size of barely detectable nodules was 604 μm (IQR, 469-756 μm) and that of barely detectable airways was 601 μm (IQR, 489-929 μm). On EID-CT, that of barely detectable nodules was 837 μm (IQR, 678-914 μm) and that of barely detectable airways was 1210 μm (IQR, 674-1435 μm). PCD-CT visualized small nodules and airways better than EID-CT and improved with high spatial resolution and potentially can detect submillimeter nodules and airways.

Effect of microplastics deposition on human lung airways: A review with computational benefits and challenges

Microplastics have become omnipresent in the environment, including the air we inhale, the water we consume, and the food we eat. Despite limited research, the accumulation of microplastics within the human respiratory system has garnered considerable interest because of its potential implications for health. This review offers a comprehensive examination of the impacts stemming from the accumulation of microplastics on human lung airways and explores the computational benefits and challenges associated with studying this phenomenon. The existence of microplastics in the respiratory system can lead to a range of adverse effects. Research has indicated that microplastics can induce inflammation, oxidative stress, and impaired lung function. Furthermore, the small size of microplastics allows them to penetrate deep into the lungs, reaching the alveoli, where gas exchange takes place. This raises concerns about long-term health consequences, such as the development of respiratory diseases and the potential for translocation to other organs. Computational approaches have been instrumental in understanding the impact of microplastic deposition on human lung airways. Computational models and simulations enable the investigation of particle dynamics, deposition patterns, and interaction mechanisms at various levels of complexity. However, studying microplastics in the lung airways using computational methods presents several challenges. The complex anatomy and physiological processes of the respiratory system require accurate representation in computational models. Obtaining relevant data for model validation and parameterization remains a significant hurdle. Additionally, the diverse nature of microplastics, including variations in size, shape, and chemical composition, poses challenges in capturing their full range of behaviours and potential toxicological effects.

Interleukin 31 receptor α promotes smooth muscle cell contraction and airway hyperresponsiveness in asthma

Asthma is a chronic inflammatory airway disease characterized by airway hyperresponsiveness (AHR), inflammation, and goblet cell hyperplasia. Multiple cytokines, including IFNγ, IL-4, and IL-13 are associated with asthma; however, the mechanisms underlying the effects of these cytokines remain unclear. Here, we report a significant increase in the expression of IL-31RA, but not its cognate ligand IL-31, in mouse models of allergic asthma. In support of this, IFNγ, IL-4, and IL-13 upregulated IL-31RA but not IL-31 in both human and mice primary airway smooth muscle cells (ASMC) isolated from the airways of murine and human lungs. Importantly, the loss of IL-31RA attenuated AHR but had no effect on inflammation and goblet cell hyperplasia in mice challenged with allergens or treated with IL-13 or IFNγ. We show that IL-31RA functions as a positive regulator of muscarinic acetylcholine receptor 3 expression, augmenting calcium levels and myosin light chain phosphorylation in human and murine ASMC. These findings identify a role for IL-31RA in AHR that is distinct from airway inflammation and goblet cell hyperplasia in asthma.

A numerical study on sedimentation effect of dust, smoke and traffic particle deposition in a realistic human lung

Inhalation of pollutants can be deadly for respiratory health, as toxic pollutants can penetrate the deep lungs which could occur severe respiratory infection and lead to life-threatening respiratory diseases. The excessive presence of pollutants in the environment increases the concern of potential respiratory health hazards. To date, a microscopic understanding of the sedimentation effect on dust, smoke and traffic (pollutant) particles transported to the airways is missing in the literature. This first-ever study aims to analyse the sedimentation effect in various directions of pollutant particle transport in airways. This study also quantitatively explains how particle size, density, and physical exercise impact pollutant particle transport and deposition (TD) in the human lung airways. The contribution of the sedimentation effect is largely independent of particle size. The sedimentation effect can also be found significant at the trachea region when the fluid flow is horizontal. Overall, traffic particles with large diameters and high flow rates are deposited in the upper lung, whereas dust particles with large diameters and high flow rates are deposited in the deep lung. It is expected that 79.1 % of the particles will reach the deep lung. The difference between the deposition rates of the horizontal and vertical lungs reduces if the particle size reduces, the flow rate increases or the particle density reduces. The deposition rate of a horizontal lung for the heaviest particles (traffic) at 15 L/min flow rate is about 4.5 % higher than that of a vertical lung with the same flow rate.

How microplastics are transported and deposited in realistic upper airways?

Microplastics are tiny plastic debris in the environment from industrial processes, various consumer items, and the breakdown of industrial waste. Recently, microplastics have been found for the first time in the airways, which increases the concern about long-term exposure and corresponding impacts on respiratory health. To date, a precise understanding of the microplastic transport to the airways is missing in the literature. Therefore, this first-ever study aims to analyze the microplastic transport and deposition within the upper lung airways. A computational fluid dynamics-discrete phase model approach is used to analyze the fluid flow and microplastic transport in airways. The sphericity concept and shape factor values are used to define the non-spherical microplastics. An accurate mesh test is performed for the computational mesh. The numerical results report that the highly asymmetric and complex morphology of the upper airway influences the flow fields and microplastic motion along with the flow rate and microplastic shape. The nasal cavity, mouth-throat, and trachea have high pressure, while a high flow velocity is observed at the area after passing the trachea. The flow rates, shape, and size of microplastics influence the overall deposition pattern. A higher flow rate leads to a lower deposition efficiency for all microplastic shapes. The nasal cavity has a high deposition rate compared to other regions. The microplastic deposition hot spot is calculated for shape and size-specific microplastic at various flow conditions. The findings of this study and more case-specific analysis will improve the knowledge of microplastic transport in airways and benefit future therapeutics development. The future study will be focused on the effect of various microplastic shapes on the human lung airways under the healthy and diseased airways conditions.

35 2D-Hexagonal Boron Nitride and Lung Exposure: Exploring Long-Term Effects in Healthy Versus Asthmatic Human Lung in Vitro Model

Abstract Inhalation is one of the most pertinent routes of exposure to nanoscale materials in occupational settings. Hexagonal boron nitride (hBN) is an emerging 2D material attracting significant attention due to its superior electrical, chemical, and thermal properties. For a successful commercial application of 2D-hBN, it is of key importance to understand their safety in occupational settings. However, long-term toxicity profile of this material is largely unknown. Here, an investigation of how 2D-hBN (obtained from Graphene Flagship consortium) interacts with lung cells of healthy versus diseased individuals has been performed. We used air−liquid interface-based exposure models to investigate the potential long-term toxicity of 2D-hBN in human lung airway epithelial cells (Calu-3) and 3D reconstituted airway epithelia (MucilairTM) of healthy and asthmatic subjects. Our results revealed that 2D-hBN was taken up by cells but did not trigger cytotoxicity at occupationally relevant repeated dose exposure for five weeks. However, screening of an immuno-cytokine/chemokine panel indicated an enhanced release of certain cytokines after exposure to 2D-hBN. In addition, we observed a pronounced intracellular accumulation of lipids in lipid droplets after exposure to 2D-hBN. Since lipid intermediates can play important roles in immune-cell activation and the development of lung diseases, we are currently analysing whether 2D-hBN induces alterations in lipid composition in healthy and asthmatic cells by applying global lipidomic profiling. Overall, our data indicate a potential correlation of certain lipid accumulation with enhanced immune signaling, highlighting the need for further studies to understand if 2D-hBN can sensitize for or aggravate pulmonary diseases.

Particle Deposition in Large-Scale Human Tracheobronchial Airways Predicted by Single-Path Modelling.

The health effects of particles are directly related to their deposition patterns (deposition site and amount) in human airways. However, estimating the particle trajectory in a large-scale human lung airway model is still a challenge. In this work, a truncated single-path, large-scale human airway model (G3-G10) with a stochastically coupled boundary method were employed to investigate the particle trajectory and the roles of their deposition mechanisms. The deposition patterns of particles with diameters (dp) of 1-10 μm are investigated under various inlet Reynolds numbers (Re = 100-2000). Inertial impaction, gravitational sedimentation, and combined mechanism were considered. With the increasing airway generations, the deposition of smaller particles (dp < 4 μm) increased due to gravitational sedimentation, while that of larger particles decreased due to inertial impaction. The obtained formulas of Stokes number and Re can predict the deposition efficiency due to the combined mechanism in the present model, and the prediction can be used to assess the dose-effect of atmospheric aerosols on the human body. Diseases in deeper generations are mainly attributed to the deposition of smaller particles under lower inhalation rates, while diseases at the proximal generations mainly result from the deposition of larger particles under higher inhalation rates.

Nanoparticle transport and deposition in a heterogeneous human lung airway tree: An efficient one path model for CFD simulations

Understanding nano-particle inhalation in human lung airways helps targeted drug delivery for treating lung diseases. A wide range of numerical models have been developed to analyse nano-particle transport and deposition (TD) in different parts of airways. However, a precise understanding of nano-particle TD in large-scale airways is still unavailable in the literature. This study developed an efficient one-path numerical model for simulating nano-particle TD in large-scale lung airway models. This first-ever one-path numerical approach simulates airflow and nano-particle TD in generations 0–11 of the human lung, accounting for 93% of the whole airway length. The one-path model enables the simulation of particle TD in many generations of airways with an affordable time. The particle TD of 5 nm, 10 nm and 20 nm particles is simulated at inhalation flow rates for two different physical activities: resting and moderate activity. It is found that particle deposition efficiency of 5 nm particles is 28.94% higher than 20 nm particles because of the higher dispersion capacity. It is further proved that the diffusion mechanism dominates the particle TD in generations 0–11. The deposition efficiency decreases with the increase of generation number irrespective of the flow rate and particle size. The effects of the particle size and flow rate on the escaping rate of each generation are opposite to the corresponding effects on the deposition rate. The quantified deposition and escaping rates at generations 0–11 provide valuable guidelines for drug delivery in human lungs.

Cellular mechanisms involved in the pathogenesis of airway remodeling in chronic lung disease

ABSTRACT Background Airway epithelial cells and lung fibroblasts play an important role in the development of chronic lung disease, but the exact mechanisms responsible have not been clarified. Our objective was to investigate the involvement of these cells in the inflammatory response associated to chronic lung disease. Methods Human lung fibroblasts and airway epithelial cells were challenged with Interleukin-1β and hypoxia, and with inhibitory (simvastatin) stimuli of the inflammatory response. Expression of markers of local inflammation ((IL-8, monocyte chemoattractant protein-1 (MCP-1), factor-κB1 (NF-κB1)), systemic inflammation ((C-reactive protein (CRP) and serum amyloid A (SAA)) and proteases matrix metalloproteinase (MMP) 9 and 12 were assessed by PCR and ELISA. Apoptosis/necrosis was analyzed by flow cytometry. Results Our results showed that the lung fibroblasts had a higher expression of local and systemic inflammation and protease activity markers when they were treated with IL-1β compared to airway epithelial cells. Under hypoxic conditions, we observed a decrease in systemic inflammation in lung fibroblasts, which was further attenuated by simvastatin. Conclusion The lung fibroblasts seem to be the main initially stimulated cells that could potentially trigger the inflammatory response, and be responsible for the eventual onset of chronic lung disease. The involvement of IL-1ß stimulation in systemic inflammatory and proteinase imbalance biomarkers is higher in lung fibroblasts. Apoptosis is not a predominant mechanism in these cells.

Preclinical evaluation of thin convex probe endobronchial ultrasound-guided transbronchial needle aspiration for intrapulmonary lesions.

BackgroundConventional flexible bronchoscopy has not achieved the high diagnostic yield for intrapulmonary lesions as seen with image-guided transthoracic biopsy. A thin convex probe endobronchial ultrasound bronchoscope (TCP-EBUS) with a 5.9-mm tip was designed to improve peripheral access over conventional EBUS bronchoscopes to facilitate real-time sampling of intrapulmonary lesions under ultrasound guidance.MethodsTCP-EBUS was inserted into the distal airways of ex-vivo human lungs to assess bronchial accessibility relative to clinically available bronchoscopes. The short- (≤1 h) and medium-term (≤10 d) safety of TCP-EBUS insertion and EBUS-guided transbronchial needle aspiration (TBNA) using a 25-gauge needle were evaluated physiologically and radiologically in live pigs. TCP-EBUS-guided TBNA feasibility was assessed in-vivo with pig intrapulmonary pseudo-tumors and ex-vivo with resected human lung cancer specimens.ResultsFor bronchial accessibility, TCP-EBUS demonstrated greater reach than the 6.6-mm convex probe endobronchial ultrasound (CP-EBUS) in all bronchi, as well as surpassed a 5.5-mm conventional bronchoscope in 63% (131/209) and a 4.8-mm conventional bronchoscope in 27% (57/209) of assessed bronchi. The median bronchial generation and the mean diameter of bronchi TCP-EBUS reached was 4 (range, 3–7) and 3.3±0.7 mm, respectively. No major complications related to TCP-EBUS-guided TBNA in distal airways were observed in the live pigs. Scattered mucosal erythema of the bronchial walls was observed immediately after TCP-EBUS insertion; this self-resolved by day 10. TCP-EBUS could successfully reach and visualize intrapulmonary targets via ultrasound, with no difficulty in needle deployment or sampling.ConclusionsTCP-EBUS has the potential to facilitate safe real-time transbronchial sampling of intrapulmonary lesions in the central and middle lung fields.

Abstract 778: Dysregulation of alternative mRNA splicing by oncogenic KRAS in lung adenocarcinoma

Abstract Alternative mRNA splicing is dysregulated in many cancers including lung adenocarcinoma. These aberrant splicing events can sometimes be explained by mutations in splice sites or splicing factors. However, the majority of mis-splicing in cancers remains unexplained. We hypothesize that oncogenic signaling pathways play a role in regulating alternative splicing. In this study, we focus on mRNA splicing activity regulated by the Ras signaling cascade, which is frequently mutated in cancers. These pathways offer avenues for therapeutic modulation through small molecule inhibitors.We took a global proteomic and transcriptomic approach to study the effects of oncogenic Ras signaling on RNA splicing in vitro. Specifically, we performed LC-MS/MS and RNA-seq profiling on normal human lung airway epithelial (AALE) cells overexpressing wild-type or mutant KRAS or RIT1 (N = 3 replicates per allele). Phosphorylation of splicing factors was preferentially downregulated in KRASmut cells compared to KRASWT cells, suggesting that oncogenic KRAS signaling regulates splicing factor activity. Additionally, of the 2227 and 2452 skipped exon (SE) events in KRASG12V and KRASQ61H cells, respectively, compared to KRASWT overexpressing cells, 1013 events were shared between the two mutants. This statistically significant overlap (p &amp;lt; 0.001, hypergeometric test) indicates that KRAS has a role in splicing regulation that is disrupted when the protein is mutated. To determine how KRAS-regulated splicing activity compared to other signaling proteins and oncogenes, we also profiled the whole transcriptomes of isogenic A549 lung adenocarcinoma cell lines overexpressing 86 wild-type or variant alleles across 27 genes implicated in lung cancers (N = 4 to 8 replicates per allele). Of all pairs of mutant and wild-type alleles tested, KRASmut cells compared to KRASWT overexpressing cells exhibited the second highest levels of alternative splicing, behind only RNA binding protein RBM45 and its mutant allele RBM45M126I. In particular, ten SE events were observed to be differentially regulated in a KRAS dependent manner in both AALE and A549 cells. One of these 10 events is the differential splicing of the Myc Associated Zinc Finger (MAZ) protein to increase the expression of its splice variant that acts as a negative regulator of transcription. As MAZ regulates expression of KRAS, this splice variant may be a mechanism for the cell to modulate wild-type KRAS levels in the presence of KRAS mutants. Our proteomic and transcriptomic profiling in lung epithelial and lung adenocarcinoma cells uncovers splicing factor activity and mRNA splicing events regulated by oncogenic KRAS. With further studies of the alternative splicing events described, it will be possible to design or repurpose therapies in order to target aberrant splicing caused by disrupted Ras signaling and its downstream effectors. Citation Format: April Lo, Maria McSharry, Alice H. Berger. Dysregulation of alternative mRNA splicing by oncogenic KRAS in lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 778.

Numerical study of nano and micro pollutant particle transport and deposition in realistic human lung airways

For respiratory health risk assessment, it is essential to evaluate the transportation and deposition (TD) of pollutant particles in human lung airways, which are responsible for lung diseases. Studies to date improved the knowledge of the particle TD in airways. However, the understanding of the TD of different pollutant particles in realistic airways has not been fully understood. This study investigates TD of three types of pollutant particles: traffic, smoke and dust, with various sizes ranging from nano- to micro-scales in the mouth–throat and tracheobronchial lung airways of a human lung using computational fluid dynamics (CFD). Three different physical activities are considered: sleeping, resting, and intense breathing, corresponding to inhalation flow rates of Qin = 15, 30 and 60 L/min, respectively. Nearly 99.8% of 10-μm traffic particles are deposited in the upper lung airways considered here. However, the TD efficiency of 10-μm dust particles is reduced to 64.28% due to the reduction in particle density. Nanoparticles have a much smaller deposition efficiency than microparticles because impaction effect of microparticles is stronger. Only less than 10% of 5-nm traffic particles are deposited in the airways for all three flow rates, allowing over 90% of particles to reach the deep lung. An important finding is that the effects of density on the particle TD of nanoparticles are much weaker than that of microparticles. At 15 L/min flow rate, the difference between the deposition efficiencies of the heaviest traffic particles and the lightest dust particles is only 3.5%. The effects of particle density on the deposition efficiencies of nano- and micro-particles are different from each other because impaction and diffusion dominate the TD of nano- and micro-particles, respectively. Density only affects impaction significantly but has little effect on diffusion.

Medicinal Plants Used for Management of Asthma in FCT, Abuja and Its Environs

&#x0D; Aim: Asthma is a condition that affects the airways in human lungs. It causes its (lungs) inflammation and hyper-responsiveness. Conventional therapies used in its management are expensive and have been found to come with undesirable side effects. The use of herbal remedies in treating the disease is widespread especially in local communities with little or no access to primary health care. This indigenous knowledge on the cure of asthma is gradually being lost among the populace. This study is aimed at documenting local remedies used in the management of asthma.&#x0D; Methodology: Ethnobotanical survey was carried out in Federal Capital Territory (FCT)- Abuja and surrounding communities, among Traditional Medicine Practitioners (TMPs), Herb’s sellers and elderly in the community using semi-structured questionnaire and interview methods. Data were analysed using descriptive statistics and ethnobotany index.&#x0D; Results: 80 respondents were interviewed, 58 of them laid claims to knowledge about medicinal plants used in asthma management. Majority of the respondents are Traditional Medicine Practitioners (48%). 59 plants species belonging to 38 plant families was documented with most belonging to the Moraceae plant family (10%). The recipes mentioned were mostly prepared as decoctions which are taken orally with a case of two being by smoking and inhalation. &#x0D; Conclusion: This study has shown that the Federal Capital Territory and settlements within its environ are blessed with medicinal plants used in the management of asthma which serve as a cheap and alternative source of remedy for the local populace and as well, being a repository for scientific inquest that may lead to yet another drug discovery from plant origin used in the management of asthma.

Aerosol Particle Transport and Deposition in Upper and Lower Airways of Infant, Child and Adult Human Lungs

Understanding transportation and deposition (TD) of aerosol particles in the human respiratory system can help clinical treatment of lung diseases using medicines. The lung airway diameters and the breathing capacity of human lungs normally increase with age until the age of 30. Many studies have analyzed the particle TD in the human lung airways. However, the knowledge of the nanoparticle TD in airways of infants and children with varying inhalation flow rates is still limited in the literature. This study investigates nanoparticle (5 nm ≤ dp ≤ 500 nm) TD in the lungs of infants, children, and adults. The inhalation air flow rates corresponding to three ages are considered as Qin=3.22 L/min (infant), 8.09 L/min (Child), and Qin=14 L/min (adult). It is found that less particles are deposited in upper lung airways (G0–G3) than in lower airways (G12–G15) in the lungs of all the three age groups. The results suggest that the particle deposition efficiency in lung airways increases with the decrease of particle size due to the Brownian diffusion mechanism. About 3% of 500 nm particles are deposited in airways G12–G15 for the three age groups. As the particle size is decreased to 5 nm, the deposition rate in G12–G15 is increased to over 95%. The present findings can help medical therapy by individually simulating the distribution of drug-aerosol for the patient-specific lung.

Potentiation of long-acting \u03b22-agonist and glucocorticoid responses in human airway epithelial cells by modulation of intracellular cAMP

IntroductionOver 300 million people in the world live with asthma, resulting in 500,000 annual global deaths with future increases expected. It is estimated that around 50–80% of asthma exacerbations are due to viral infections. Currently, a combination of long-acting beta agonists (LABA) for bronchodilation and glucocorticoids (GCS) to control lung inflammation represent the dominant strategy for the management of asthma, however, it is still sub-optimal in 35–50% of moderate-severe asthmatics resulting in persistent lung inflammation, impairment of lung function, and risk of mortality. Mechanistically, LABA/GCS combination therapy results in synergistic efficacy mediated by intracellular cyclic adenosine monophosphate (cAMP).HypothesisIncreasing intracellular cAMP during LABA/GCS combination therapy via inhibiting phosphodiesterase 4 (PDE4) and/or blocking the export of cAMP by ATP Binding Cassette Transporter C4 (ABCC4), will potentiate anti-inflammatory responses of mainstay LABA/GCS therapy.MethodsExpression and localization experiments were performed using in situ hybridization and immunohistochemistry in human lung tissue from healthy subjects, while confirmatory transcript and protein expression analyses were performed in primary human airway epithelial cells and cell lines. Intervention experiments were performed on the human airway epithelial cell line, HBEC-6KT, by pre-treatment with combinations of LABA/GCS with PDE4 and/or ABCC4 inhibitors followed by Poly I:C or imiquimod challenge as a model for viral stimuli. Cytokine readouts for IL-6, IL-8, CXCL10/IP-10, and CCL5/RANTES were quantified by ELISA.ResultsUsing archived human lung and human airway epithelial cells, ABCC4 gene and protein expression were confirmed in vitro and in situ. LABA/GCS attenuation of Poly I:C or imiquimod-induced IL-6 and IL-8 were potentiated with ABCC4 and PDE4 inhibition, which was greater when ABCC4 and PDE4 inhibition was combined. Modulation of cAMP levels had no impact on LABA/GCS modulation of Poly I:C-induced CXCL10/IP-10 or CCL5/RANTES.ConclusionModulation of intracellular cAMP levels by PDE4 or ABCC4 inhibition potentiates LABA/GCS efficacy in human airway epithelial cells challenged with viral stimuli. The data suggest further exploration of the value of adding cAMP modulators to mainstay LABA/GCS therapy in asthma for potentiated anti-inflammatory efficacy.

Activation of Tenofovir Alafenamide and Sofosbuvir in the Human Lung and Its Implications in the Development of Nucleoside/Nucleotide Prodrugs for Treating SARS-CoV-2 Pulmonary Infection.

ProTide technology is a powerful tool for the design of nucleoside/nucleotide analog prodrugs. ProTide prodrug design improves cell permeability and enhances intracellular activation. The hydrolysis of the ester bond of a ProTide is a determinant of the intracellular activation efficiency and final antiviral efficacy of the prodrug. The hydrolysis is dictated by the catalytic activity and abundance of activating enzymes. The antiviral agents tenofovir alafenamide (TAF) and sofosbuvir (SBV) are typical ProTides. Both TAF and SBV have also been proposed to treat patients with COVID-19. However, the mechanisms underlying the activation of the two prodrugs in the lung remain inconclusive. In the present study, we profiled the catalytic activity of serine hydrolases in human lung S9 fractions using an activity-based protein profiling assay. We evaluated the hydrolysis of TAF and SBV using human lung and liver S9 fractions and purified enzymes. The results showed that CatA and CES1 were involved in the hydrolysis of the two prodrugs in the human lung. More specifically, CatA exhibited a nearly 4-fold higher hydrolytic activity towards TAF than SBV, whereas the CES1 activity on hydrolyzing TAF was slightly lower than that for SBV. Overall, TAF had a nearly 4-fold higher hydrolysis rate in human lung S9 than SBV. We further analyzed protein expression levels of CatA and CES1 in the human lung, liver, and primary cells of the two tissues using proteomics data extracted from the literature. The relative protein abundance of CatA to CES1 was considerably higher in the human lung and primary human airway epithelial cells than in the human liver and primary human hepatocytes. The findings demonstrated that the high susceptivity of TAF to CatA-mediated hydrolysis resulted in efficient TAF hydrolysis in the human lung, suggesting that CatA could be utilized as a target activating enzyme when designing antiviral ester prodrugs for the treatment of respiratory virus infection.

PRECLINICAL EVALUATION OF THIN CONVEX PROBE ENDOBRONCHIAL ULTRASOUND-GUIDED TRANSBRONCHIAL NEEDLE ASPIRATION FOR INTRAPULMONARY LESIONS

TOPIC: Procedures TYPE: Original Investigations PURPOSE: A prototype thin convex probe endobronchial ultrasound scope (TCP-EBUS; distal outer diameter [OD] 5.9 mm; Olympus Medical Systems Corp., Japan) was developed to enable access to distal airways and diagnose intrapulmonary lesions. The objective of this study was to evaluate the potential clinical utility of TCP-EBUS by preclinically assessing its bronchial accessibility, the feasibility of EBUS-guided transbronchial needle aspiration (EBUS-TBNA) of intrapulmonary targets, as well as its short- and medium-term safety. METHODS: For bronchial accessibility, the TCP-EBUS was inserted into the distal airways of ex-vivo human lungs (n=5). TCP-EBUS was compared with several clinically-available bronchoscopes (BF-H190 bronchoscope, OD 5.5 mm; BF-Q190 bronchoscope, OD 4.8 mm; BF-Y0063 CP-EBUS scope, OD 6.6 mm, Olympus Medical Systems Corp., Japan). The maximum reach, in terms of bronchial generation, for each scope was documented using fluoroscopy and bronchoscopy. To quantify the minimum diameter of the distal airway accessed by the TCP-EBUS, an agarose-barium sulfate mixture was injected transbronchially to mark the bronchus where the TCP-EBUS could reach, followed by cone-beam CT to measure the diameter radiographically (n=3). For intrapulmonary lesion EBUS-TBNA feasibility, an agarose-barium mixture was injected transbronchially into the lungs in a live pig to create pseudo-tumor targets; successful EBUS-TBNA was based on retrieval of dyed agarose material. The short- (≤1 hr) and medium-term (≤10 d) safety of TCP-EBUS insertion and EBUS-TBNA in the periphery were observed physiologically and radiologically (fluoroscopy, computed tomography [CT]) in live pigs (n=5). RESULTS: For bronchial accessibility, TCP-EBUS demonstrated greater reach than the standard CP-EBUS in all bronchi, as well as surpassed the 5.5 mm-bronchoscope in 62.7% (131/209) and the 4.8 mm-bronchoscope in 27.2% (57/209) of assessed bronchi. The median bronchial generation and the mean diameter of bronchi TCP-EBUS reached was 4 (range 3-7) and 3.3±0.7 mm, respectively. No difficulties with EBUS-TBNA of intrapulmonary pseudo-tumors were observed. No major complications related to TCP-EBUS-TBNA in distal airways were observed in the five pigs. Scattered mucosal erythema of the bronchial walls was observed immediately after TCP-EBUS insertion in all pigs; this self-resolved by day 10. One pig developed an inflammatory scar in the right upper lobe by day 10. CONCLUSIONS: TCP-EBUS insertion appears to be safe and improves access to the distal airways. It has the potential to facilitate EBUS-TBNA of intrapulmonary lesions in the central and middle lung fields. CLINICAL IMPLICATIONS: Ultrasound-guided real-time sampling for intrapulmonary lesions located in the inner two-thirds lung fields may be safely conducted with the TCP-EBUS bronchoscope. DISCLOSURES: No relevant relationships by Masato Aragaki, source=Web Response No relevant relationships by Nicholas Bernards, source=Web Response No relevant relationships by Harley Chan, source=Web Response No relevant relationships by Zhenchian Chen, source=Admin input No relevant relationships by Andrew Effat, source=Web Response No relevant relationships by Alexander Gregor, source=Web Response No relevant relationships by Terunaga Inage, source=Web Response No relevant relationships by TSUKASA ISHIWATA, source=Web Response No relevant relationships by Tomonari Kinoshita, source=Web Response No relevant relationships by Yamato Motooka, source=Web Response no disclosure on file for Koichiro Tatsumi; No relevant relationships by Hideki Ujiie, source=Web Responseresearch support relationship with Olympus Corporation Please note: $5001 - $20000 by Kazuhiro Yasufuku, source=Web Response, value=Grant/Research Consultant relationship with Olympus America Inc Please note: $1001 - $5000 by Kazuhiro Yasufuku, source=Web Response, value=Consulting fee Consultant relationship with Medtronic Please note: $1001 - $5000 by Kazuhiro Yasufuku, source=Web Response, value=Consulting fee Consultant relationship with Johnson and Johnson Please note: $1001 - $5000 by Kazuhiro Yasufuku, source=Web Response, value=Consulting fee Consultant relationship with Auris Surgical Robotics Please note: $1001 - $5000 by Kazuhiro Yasufuku, source=Web Response, value=Consulting fee

Numerical simulation of the unsteady flow field in the human pulmonary acinus

Understanding of airflow dynamics in the human pulmonary acinus is important for increasing targeted drug effectiveness and determining the health impact of toxic aerosols. However, there is a lack of quantitative data about the pulmonary airflow in realistic and flexible idealized geometries. This paper aims to numerically analyse the flow field of the pulmonary acinus using the computational fluid dynamics (CFD) model during transient breathing. Three-dimensional models with rhythmically expanding-contracting alveolar walls were developed for representing the pulmonary region of the human lung. Three different breathing scenarios were applied in the CFD simulations. The results showed that the transient flow conditions determined the transitions between flow types. The recirculating flow in the alveoli was observed for all cases and it was determined that its intensity depended on the breathing scenario. The flow velocity in the alveoli was slower than that of the channel flow. As we moved deeper into the lung, the flow pattern inside the alveoli exhibited a radial velocity profile. It was found that the alveolar flow exhibited a typical stenotic channel flow characteristics. As a result, the acinus models used in this study takes into account the alveolar wall motion based on physiological breathing conditions. To simulate or estimate the airflow dynamics, thus, the results obtained in this study can be easily utilized in the human lung airway models.

Aging effects on airflow distribution and micron-particle transport and deposition in a human lung using CFD-DPM approach

Understanding the transportation and deposition (TD) of inhaled aerosol particles in human lung airways is important for health risk assessment and therapeutic efficiency of targeted drug delivery. The particle TD into a human lung depends on lung anatomy, breathing pattern, as well as particle properties. The breathing capacity and lung airway diameters can be reduced by about 10% every 10 years after the age of 50. However, the age-specific particle TD in human lungs, particularly in the aged, has not been well understood in literature. This study investigates the particle TD in the lungs of people aged 50–70 years, using computational fluid dynamics (CFD). A new cutting method that splits the lung model into different sections has been developed as a feasible CFD method to simulate the particle TD in G0 to G14 lung airways. The inhalation of micron scale particles with three diameters (5 μm, 10 μm and 20 μm) and a constant air flow rate in inhalation is considered. It is found that different sized particles are deposited in different generation airways. Nearly 100% of 20 μm particles are deposited in the upper lung airways (G0-G5) and no particles pass through G7. Particles can go into deeper airways as their diameter decreases. When the particle size is decreased to 5 μm, over 48% of particles can pass through G14 and enter the deeper lung airways. An increase in age causes more particles to deposit in the upper airway and fewer particles to enter the deeper airways.

Human Primary Airway Basal Cells Display a Continuum of Molecular Phases from Health to Disease in Chronic Obstructive Pulmonary Disease.

Airway basal cells are crucial for regeneration of the human lung airway epithelium and are believed to be important contributors to chronic obstructive pulmonary disease (COPD) and other lung disorders. To reveal how basal cells contribute to disease and to discover novel therapeutic targets, these basal cells need to be further characterized. In this study, we optimized a flow cytometry-based cell sorting protocol for primary human airway basal cells dependent on cell size and NGFR (nerve-growth factor receptor) expression. The basal cell population was found to be molecularly and functionally heterogeneous, in contrast to cultured basal cells. In addition, significant differences were found, such as KRT14 expression exclusively existing in cultured cells. Also, colony-forming capacity was significantly increased in cultured cells showing a clonal enrichment in vitro. Next, by single-cell RNA sequencing on primary basal cells from healthy donors and patients with Global Initiative for Chronic Obstructive Lung Disease stage IV COPD, the gene expression revealed a continuum ranging from healthy basal cell signatures to diseased basal cell phenotypes. We identified several upregulated genes that may indicate COPD, such as stress response-related genes GADD45B and AHSA1, together with with genes involved in the response to hypoxia, such as CITED2 and SOD1. Taken together, the presence of healthy basal cells in stage IV COPD demonstrates the potential for regeneration through the discovery of novel therapeutic targets. In addition, we show the importance of studying primary basal cells when investigating disease mechanisms as well as for developing future cell-based therapies in the human lung.