Lung Compartments Research Articles

Targeting Immune Cells.

The respiratory tract with its vast surface area and very thin air-blood tissue barrier presents an extremely large interface for potential interaction with xenobiotics such as inhaled pathogens or medicaments. To protect its large and vulnerable surface, the lung is populated with several different types of immune cells. Pulmonary epithelial cells, macrophages and dendritic cells are key players in shaping the innate and adaptive immune response. Due to their localization, they represent a frontline of cell populations that are among the first to come in contact with inhaled xenobiotics. Furthermore, depending on the lung compartment they populate, these cells show a large variety in morphology, phenotype, and function. These unique characteristics make those cell populations ideal targets for specific immunomodulators that are designed for inhalation. Depending on cell population or lung compartment targeting, a specific immune response may be triggered or modulated. The purpose of a potent carrier for pulmonary immunomodulation is, first, to efficiently target a specific immunocompetent cell and, second, to affect its role in generating an immune response. Immunomodulation may occur at different levels of immune cell-antigen interaction, i.e. antigen uptake, trafficking, processing and presentation. Inhalation of nanosized carriers for drugs or vaccines shows great potential for both prophylactic and therapeutic approaches in order to modulate immune responses locally or systemically, due to the specific deposition and targeting properties of nanoparticles. Immune responses triggered by nanosized particles may be either immunostimulatory or immunosuppressive and depending on the specific purpose, stimulation or suppression may either be desired or unwanted. Meticulous analysis of immunomodulatory potential, pharmacologic and toxicologic testing of inhalable nanocarriers is required in order to find novel and optimal approaches for prophylaxis and therapy of pulmonary diseases. The design and characterization of such nanoparticles requires well-coordinated interdisciplinary research among engineers, biologists and clinicians.

Toxicokinetic modelling of the synthetic cannabinoid 5F-MDMB-P7AICA and its main metabolite in pigs following pulmonary administration.

Since their emergence on the drug market, synthetic cannabinoids (SC) are still gaining increasing importance in forensic toxicology. The representatives of the so-called new psychoactive substances have in common that they have not undergone preclinical safety studies. Hence, knowledge on toxicokinetic (TK) data is sparse. As an alternative to human studies not being allowed for ethical reasons, a sophisticated pig model was applied in the present study to assess the TK of the SC 5F-MDMB-P7AICA. Pigs pulmonarily received 5F-MDMB-P7AICA via an ultrasonic nebulizer. The parent compound and its main metabolite 5F-MDMB-P7AICA dimethyl butanoic acid were determined in serum and whole blood using liquid chromatography-tandem mass spectrometry. Obtained data was analysed by population (pop) TK modelling. The final pop TK model parameters for pigs were upscaled via allometric scaling techniques for the prediction of human exposure. The serum concentration-time profiles of the parent and the pop TK analysis revealed that a 4-compartment model best describes the TK data. The administration of the aerosol into the lung compartment follows zero-order kinetics. A transit compartment was further included to accurately describe the time delay between detection of the parent and the metabolite. Despite the different structure, TK parameters were found to be comparable to other examined SC. The predictions of human SC exposure suggest that multiple administration of 5F-MDMB-P7AICA substantially enhances the window of detection. The simulations pose extrapolation of the data used for model development with respect to dose linearity and allometric scaling to humans.

Lymphangioleiomyomatosis: A Review.

Lymphangioleiomyomatosis is a rare multisystem disorder belonging to the family of neoplasms exhibiting perivascular epithelioid differentiation. It primarily affects women of childbearing age. The disease is characterized by a proliferation of smooth muscle-like cells (lymphangioleiomyomatosis cells) within all lung compartments, leading to cystic parenchymal destruction and, in some cases, respiratory failure. These cells carry mutations in one or both tuberous sclerosis (TSC) genes and coexpress smooth muscle and melanocytic markers. Female hormones, particularly estrogens, influence the course of the disease. Symptoms of lymphangioleiomyomatosis vary significantly among patients, ranging from exertional dyspnea and coughing to chest pain and recurrent pneumothorax. To present the latest advancements in the understanding of disease pathogenesis and diagnosis, illustrate the pathologic and radiologic findings, provide a reference for pathologists and other health care professionals, briefly discuss recent evidence-based therapeutic approaches, and emphasize the importance of adopting a multidisciplinary approach to diagnosis and optimization of patient care. A comprehensive review of pertinent medical literature published in the last 30 years, focusing on publications written in the English language, was performed. Despite the recent significant advancements in the understanding and management of lymphangioleiomyomatosis, there are still significant gaps in our knowledge of its pathophysiology and the role of the immune system in the genesis and progression of the disease. The current changes in diagnostic algorithms favor the adoption of minimally invasive procedures as the standard of care. As a result, the clinical laboratory will play a larger role in the diagnosis of lymphangioleiomyomatosis, and surgical pathologists will likely be less involved in the diagnosis of pulmonary lymphangioleiomyomatosis than they currently are.

Uncovering cell-type-specific immunomodulatory variants and molecular phenotypes in COVID-19 using structurally resolved protein networks

Immunomodulatory variants that lead to the loss or gain of specific protein interactions often manifest only as organismal phenotypes in infectious disease. Here, we propose a network-based approach to integrate genetic variation with a structurally resolved human protein interactome network to prioritize immunomodulatory variants in COVID-19. We find that, in addition to variants that pass genome-wide significance thresholds, variants at the interface of specific protein-protein interactions, even though they do not meet genome-wide thresholds, are equally immunomodulatory. The integration of these variants with single-cell epigenomic and transcriptomic data prioritizes myeloid and Tcell subsets as the most affected by these variants across both the peripheral blood and the lung compartments. Of particular interest is a common coding variant that disrupts the OAS1-PRMT6 interaction and affects downstream interferon signaling. Critically, our framework is generalizable across infectious disease contexts and can be used to implicate immunomodulatory variants that do not meet genome-wide significance thresholds.

What is the Link between Lung Involvement and Anti-CCP Antibodies in Rheumatoid Arthritis: A Cross-sectional Study.

In Rheumatoid Arthritis (RA), pulmonary involvement is one of the most frequent extra-articular manifestations. Several studies have demonstrated an association between RA-related lung disease and the positivity of anti-cyclic citrullinated peptide (anti-CCP) antibodies. Our aim is to describe the frequency of pulmonary involvement in the RA population and investigate the association between anti-CCP antibodies and diverse lung compartment involvement in RA patients. An observational retrospective cross-sectional study was conducted, during which data were collected from the medical records of the patients with RA who had been tested for anti-CCP antibodies and had thoracic high resolution computerized tomography (HRCT) evaluation from January 2011 to March 2022. The univariate and multivariate analyses using logistic regression models was performed to calculate odds ratios (ORs) with 95% CIs. A total of 390 patients with RA were included, the mean age of patients was 58.99 ± 12.44 years, with a predominance of females (85.9%). Two hundred and fifty-two (64.6%) patients were positive for anti-CCP antibodies. The frequency of RA-related lung diseases was 14.4% (n=56). The different manifestations observed in the thoracic HRCT included Nodules (67.9%), Interstitial lung disease (ILD) (28.6%), bronchiectasis (25%), fibrosis (21.4%), obliterative bronchiolitis (7.1%), and pleuritis (1.8%). In univariate and multivariate analysis, pulmonary involvement was associated with positive anti-CCP antibodies with an odds ratio (OR) of 5.25 (95% CI: 2.17-12.70, p < 0.0001). The study demonstrated a positive association between anti-CCP antibodies and pulmonary involvement in RA and highlighted the importance of tight monitoring in RA patients with positive anti-CCP for pulmonary complications.

Pulmonary Administration of TLR2/6 Agonist after Allergic Sensitization Inhibits Airway Hyper-Responsiveness and Recruits Natural Killer Cells in Lung Parenchyma.

Asthma is a chronic lung disease with persistent airway inflammation, bronchial hyper-reactivity, mucus overproduction, and airway remodeling. Antagonizing T2 responses by triggering the immune system with microbial components such as Toll-like receptors (TLRs) has been suggested as a therapeutic concept for allergic asthma. The aim of this study was to evaluate the effect of a TLR2/6 agonist, FSL-1 (Pam2CGDPKHPKSF), administered by intranasal instillation after an allergic airway reaction was established in the ovalbumin (OVA) mouse model and to analyze the role of natural killer (NK) cells in this effect. We showed that FSL-1 decreased established OVA-induced airway hyper-responsiveness and eosinophilic inflammation but did not reduce the T2 or T17 response. FSL-1 increased the recruitment and activation of NK cells in the lung parenchyma and modified the repartition of NK cell subsets in lung compartments. Finally, the transfer or depletion of NK cells did not modify airway hyper-responsiveness and eosinophilia after OVA and/or FSL-1 treatment. Thus, the administration of FSL-1 reduces airway hyper-responsiveness and bronchoalveolar lavage eosinophilia. However, despite modifications of their functions following OVA sensitization, NK cells play no role in OVA-induced asthma and its inhibition by FSL-1. Therefore, the significance of NK cell functions and localization in the airways remains to be unraveled in asthma.

CARETestLung: A mechanical test lung with Configurable airway Resistance, lung Elastance, and breathing efforts

A mechanical test lung is a crucial tool in accurately simulating patient-specific physiological responses of patients undergoing mechanical ventilation (MV), which, in turn, offer clinicians insight into lung mechanics during MV. In particular, it can be used to facilitate better methods to identify optimal ventilator settings, modes for individual patients by providing a platform to experiment with different MV settings. This addresses the challenge of optimising MV settings caused by variability in pathological conditions and the progression of respiratory disease over time within patients. However, the accessibility and cost of versatile test lungs limit widespread adoption in clinical settings, underscoring the need for affordable alternatives. This paper presents detailed instructions for the design and construction of a replicable, cost-effective mechanical test lung. The design features 3 subsystems: 1) the lung compartment; 2) the airway; and 3) a spontaneous breathing system. A detailed tests series shows its ability to replicate clinically realistic lung elastance values ranging from 25 to 85 cmH2O/L and airway resistance values from 10 to 45 cmH2O·s/L. It can also simulate a range of clinically realistic spontaneous breathing patterns. These capabilities yield pressure and flow ventilation data comparable to certified clinical test lungs across diverse scenarios, as well as matching clinically observed behaviours and dynamics. This accessible and versatile test lung offers valuable opportunities for optimising MV settings and advancing patient care, as well as its use in developing a range of physiological models for model-based decision support.

Concurrent TB and HIV therapies effectively control clinical reactivation of TB during co-infection but fail to eliminate chronic immune activation.

The majority of Human Immunodeficiency Virus (HIV) negative individuals exposed to Mycobacterium tuberculosis (Mtb) control the bacillary infection as latent TB infection (LTBI). Co-infection with HIV, however, drastically increases the risk to progression to tuberculosis (TB) disease. TB is therefore the leading cause of death in people living with HIV (PLWH) globally. Combinatorial antiretroviral therapy (cART) is the cornerstone of HIV care in humans and reduces the risk of reactivation of LTBI. However, the immune control of Mtb infection is not fully restored by cART as indicated by higher incidence of TB in PLWH despite cART. In the macaque model of co-infection, skewed pulmonary CD4+ TEM responses persist, and new TB lesions form despite cART treatment. We hypothesized that regimens that concurrently administer anti-TB therapy and cART would significantly reduce TB in co-infected macaques than cART alone, resulting in superior bacterial control, mitigation of persistent inflammation and lasting protective immunity. We studied components of TB immunity that remain impaired after cART in the lung compartment, versus those that are restored by concurrent 3 months of once weekly isoniazid and rifapentine (3HP) and cART in the rhesus macaque (RM) model of LTBI and Simian Immunodeficiency Virus (SIV) co-infection. Concurrent administration of cART + 3HP did improve clinical and microbiological attributes of Mtb/SIV co-infection compared to cART-naïve or -untreated RMs. While RMs in the cART + 3HP group exhibited significantly lower granuloma volumes after treatment, they, however, continued to harbor caseous granulomas with increased FDG uptake. cART only partially restores the constitution of CD4 + T cells to the lung compartment in co-infected macaques. Concurrent therapy did not further enhance the frequency of reconstituted CD4+ T cells in BAL and lung of Mtb/SIV co-infected RMs compared to cART, and treated animals continued to display incomplete reconstitution to the lung. Furthermore, the reconstituted CD4+ T cells in BAL and lung of cART + 3HP treated RMs exhibited an increased frequencies of activated, exhausted and inflamed phenotype compared to LTBI RMs. cART + 3HP failed to restore the effector memory CD4+ T cell population that was significantly reduced in pulmonary compartment post SIV co-infection. Concurrent therapy was associated with the induction of Type I IFN transcriptional signatures and led to increased Mtb-specific TH1/TH17 responses correlated with protection, but decreased Mtb-specific TNFa responses, which could have a detrimental impact on long term protection. Our results suggest the mechanisms by which Mtb/HIV co-infected individuals remain at risk for progression due to subsequent infections or reactivation due of persisting defects in pulmonary T cell responses. By identifying lung-specific immune components in this model, it is possible to pinpoint the pathways that can be targeted for host-directed adjunctive therapies for TB/HIV co-infection.

Inhalable drug-loaded silk fibroin carriers for pulmonary drug delivery.

The design and development of engineered micro and nano-carriers offering superior therapeutic performance compared to traditional delivery forms, are crucial in pharmaceutical research. Aerosolization and inhalation of carriers with improved solubility/stability of insoluble drugs, has huge potential for targeted drug delivery (DD) in various pulmonary diseases. Indeed, dedicated carriers must meet specific dimensional rules for proper lung delivery. Particles between 2-10 μm in size are normally deposited in the tracheobronchial region, while particles of 0.5-2 μm may be properly deposited in the alveoli. In this work, we report the development of inhalable nanostructured carries made of a 'green' bio-inspired polymer from aqueous solutions, i.e. silk fibroin (SF), efficiently loaded with a hydrophobic drug, i.e. the thyroid hormone levothyroxine (L-T4), a drug for the treatment of idiopathic pulmonary fibrosis. The aim is to optimize a standard method for the synthesis of SF-based nanocarriers with controlled size and shape, where a fine control of their geometrical properties is aimed at efficiently controlling the pulmonary DD. L-T4 loaded SF particles were synthesized through a one-pot co-precipitation method. Optimized systems were determined by varying the chemo-physical parameters during the synthesis. Ethylenediaminetetraacetic acid (EDTA) was used to remove CaCO3 cores. The proposed synthesis routes have led to two SF structures, whose structural heterogeneity and nanostructured morphology have been demonstrated using fluorescence microscopy, DLS, SEM and EDX. Two systems with varying shape and size have been obtained: (i) a flat disk-like SF structure with an irregular surface and an in-plane length of about 1-2 μm; (ii) solid SF nanospheres, obtained using ethylene glycol as additive, showing two size populations (main diameters of 0.5 μm and 1.7 μm). Solid nanospherical systems, in particular, show a tendency to arrange into agglomerates that, when loosely bound into smaller particles, can facilitate the delivery at the alveoli. Both formulations exhibited similar drug loading efficiencies, evaluated by HPLC analysis. However, SF nanospheres showed greater in vitro drug release after 24 hours. The demonstrated control over the characteristics imparted to the proposed DD systems may be critical to select the most suitable size/shape to achieve high rates of delivery to the appropriate lung compartment.

Ronapreve (REGN-CoV; casirivimab and imdevimab) reduces the viral burden and alters the pulmonary response to the SARS-CoV-2 Delta variant (B.1.617.2) in K18-hACE2 mice using an experimental design reflective of a treatment use case.

With some exceptions, global policymakers have recommended against the use of existing monoclonal antibodies in COVID-19 due to loss of neutralization of newer variants. The purpose of this study was to investigate the impact of Ronapreve on compartmental viral replication using paradigms for susceptible and insusceptible variants. Virological efficacy and impact on pathogenicity was assessed in K18-hACE2 mice inoculated with either the Delta or BA.1 Omicron variants. Ronapreve reduced sub-genomic viral RNA levels in lung and nasal turbinate, 4 and 6 days post-infection, for the Delta variant but not the Omicron variant. It also blocked brain infection, which is seen with high frequency in K18-hACE2 mice after Delta variant infection. At day 6, the inflammatory response to lung infection with the Delta variant was altered to a multifocal granulomatous inflammation in which the virus appeared to be confined. The current study provides evidence of an altered tissue response to SARS-CoV-2 after treatment with a monoclonal antibody combination that retains neutralization activity. These data demonstrate that experimental designs that reflect treatment use cases are achievable in animal models for monoclonal antibodies. Extreme caution should be taken when interpreting prophylactic experimental designs that may not be representative of treatment.IMPORTANCEFollowing the emergence of the SARS-CoV-2 Omicron variant, the WHO recommended against the use of Ronapreve in its COVID-19 treatment guidelines due to a lack of efficacy based on current pharmacokinetic-pharmacodynamic understanding. However, the continued use of Ronapreve, specifically in vulnerable patients, was advocated by some based on in vitro neutralization data. Here, the virological efficacy of Ronapreve was demonstrated in both the lung and brain compartments using Delta as a paradigm for a susceptible variant. Conversely, a lack of virological efficacy was demonstrated for the Omicron variant. Comparable concentrations of both monoclonal antibodies were observed in the plasma of Delta- and Omicron-infected mice. This study made use of a reliable murine model for SARS-CoV-2 infection, an experimental design reflective of treatment, and demonstrated the utility of this approach when assessing the effectiveness of monoclonal antibodies.

#1356 Kidney phenotype in interstitial lung disease associated with ANCA-vasculitis: European Multicentre Study

Abstract Background and Aims Interstitial lung disease (ILD) in ANCA-associated vasculitis (AAV) has the appearance of a progressive fibrotic disease on imaging and primarily affects the interstitial lung compartment and is usually associated with MPO-ANCA. Whether patients with AAV-ILD display a similar fibrotic pattern in their kidneys is unclear. Method A European multicentre retrospective study included patients with AAV-ILD. The diagnosis of ILD was confirmed by a CT chest pattern of usual interstitial pneumonia (UIP), non-specific interstitial pneumonia (NSIP), organising pneumonia or chronic hypersensitivity pneumonia. We aimed to determine if kidney involvement in AAV-ILD exhibited a more fibrotic pattern compared to AAV-related nephritis without ILD, using data from the Cambridge AAV cohort. Results 135 patients with AAV-ILD were included; 94 (70%) had also kidney involvement, in whom the mean age was 71 ± 11 years and 87% MPO-ANCA positive. The ILD diagnosis preceded AAV in 17%, 64% presented concurrently with kidney involvement, 20% with pulmonary haemorrhage. The most common lung radiological pattern was UIP (67%). At presentation, the median glomerular filtration rate (GFR) was 27 ml/min per 1.73 m2 (interquartile range 12-50), with a median albumin-to creatinine ratio 23 mg/mmol (IQR 10-97). Among 72 patients with available kidney biopsy, the most prevalent Berden class was focal in 45%, followed by mixed in 33%, crescentic in 18% and sclerotic in 4%. Although, the prevalence of Berden classes did not significantly differ between ILD-nephritis and no ILD-nephritis groups, the former group had a higher baseline GFR (p = 0.05), lower albuminuria level (p = 0.002), higher percentage of normal glomeruli (p = 0.027), lower glomerular necrosis percentage (p = 0.002) and higher interstitial fibrosis score (p = 0.049). Within five years, the ILD-nephritis group demonstrated renal recovery, as indicated by an adjusted mean delta GFR of 13.4 ml/min per 1.73 m2, without a significant difference compared to the no ILD-nephritis group. Over a median follow-up of 4.9 years (IQR 2-9), the progression to end-stage kidney disease (ESKD) was comparable between the groups. However, notably, the ILD-nephritis group experienced significantly poorer survival rates (mean 10.9 years vs 17.9 years, log-rank p &amp;lt; 0.001). Conclusion In AAV-ILD, kidney involvement is often characterized by fewer inflammatory and a higher prevalence of fibrotic lesions than on non-ILD-AAV. Despite initial differences in renal pathology and kidney function between these groups, both demonstrated similar risks of progressing to ESKD. Nevertheless, it's crucial to underscore the significant influence of ILD on the overall outcomes of AAV patients with kidney involvement.

Respiratory Assist Devices in Pulmonary Rehabilitation.

Patients with advanced lung disease, especially patients with COPD, suffer from dyspnea at rest that worsens during the performance of even limited physical activities. The causes of dyspnea are multifactorial and are related to structural changes found in the parenchymal compartment of the lung as well as the airway and pulmonary vasculature. Alterations in any of the lung compartments may have negative consequences for the physiological performance of exercise. Respiratory assist devices that attenuate the pathophysiological derangements induced by the underlying lung disease, and/or unload the increased work of breathing, can enhance the performance of exercise, and help to produce more robust training effects in patients with lung disease. Herein we review the data that examines these approaches using respiratory assist devices to improve exercise outcomes in patients with COPD.

Differential Gene Expression in Porcine Lung Compartments after Experimental Infection with Mycoplasma hyopneumoniae.

Mycoplasma hyopneumoniae (Mhyo) is the causative agent of porcine enzootic pneumonia (EP), as well as one of the main pathogens involved in the porcine respiratory disease complex. The host-pathogen interaction between Mhyo and infected pigs is complex and not completely understood; however, improving the understanding of these intricacies is essential for the development of effective control strategies of EP. In order to improve our knowledge about this interaction, laser-capture microdissection was used to collect bronchi, bronchi-associated lymphoid tissue, and lung parenchyma from animals infected with different strains of Mhyo, and mRNA expression levels of different molecules involved in Mhyo infection (ICAM1, IL-8, IL-10, IL-23, IFN-α, IFN-γ, TGF-β, and TNF-α) were analyzed by qPCR. In addition, the quantification of Mhyo load in the different lung compartments and the scoring of macroscopic and microscopic lung lesions were also performed. Strain-associated differences in virulence were observed, as well as the presence of significant differences in expression levels of cytokines among lung compartments. IL-8 and IL-10 presented the highest upregulation, with limited differences between strains and lung compartments. IFN-α was strongly downregulated in BALT, implying a relevant role for this cytokine in the immunomodulation associated with Mhyo infections. IL-23 was also upregulated in all lung compartments, suggesting the potential involvement of a Th17-mediated immune response in Mhyo infections. Our findings highlight the relevance of Th1 and Th2 immune response in cases of EP, shedding light on the gene expression levels of key cytokines in the lung of pigs at a microscopic level.

The Role of Lung Density in the Voxel-Based Dosimetry of 90Y-TARE Evaluated with the Voxel S-Value (VSV) Method and Fast Monte Carlo Simulation

(1) Background: In 90Y-TARE treatments, lung-absorbed doses should be calculated according to the manufacturer’s instructions, using the MIRD-scheme. This scheme is derived from the assumption that 90Y-microspheres deliver the dose in a water-equivalent medium. Since the density of the lungs is quite different from that of the liver, the absorbed dose to the lungs could vary considerably, especially at the liver/lungs interface. The aim of this work is to compare the dosimetric results obtained by two dedicated software packages implementing a water-equivalent dose calculation and a Monte Carlo (MC) simulation, respectively. (2) Methods: An anthropomorphic IEC phantom and a retrospective selection of 24 patients with a diagnosis of HCC were taken into account. In the phantom study, starting from a 90Y-PET/CT acquisition, the liver cavity was manually fixed with a uniform activity concentration on PET series, while the lung compartment was manually expanded on a CT series to simulate a realistic situation in which the liver and lungs are adjacent. These steps were performed by using MIM 90Y SurePlan. Then, a first simulation was carried out with only the liver cavity filled, while a second one was carried out, in which the lung compartment was also manually fixed with a uniform activity concentration corresponding to 10% lung shunt fraction. MIM 90Y SurePlan was used to obtain Voxel S-Value (VSV) approach dose values; instead, Torch was used to obtain MC approach dose values for both the phantom and the patients. (3) Results: In the phantom study, the percentage mean dose differences (∆D%) between VSV and MC in the first and second simulation, respectively were found to be 1.2 and 0.5% (absolute dose variation, ∆D, of 0.7 and 0.3 Gy) for the liver, −56 and 70% (∆D of −0.3 and −16.2 Gy) for the lungs, and −48 and −60% (∆D of −4.3 and −16.5 Gy) for the Liver/Lungs Edge region. The patient study reports similar results with ∆D% between VSV and MC of 7.0%, 4.1% and 6.7% for the whole liver, healthy liver, and tumor, respectively, while the result was −61.2% for the left lung and −61.1% for both the right lung and lungs. (4) Conclusion: Both VSV and MC allowed accurate radiation dose estimation with small differences (&lt;7%) in regions of uniform water-equivalent density (i.e., within the liver). Larger differences between the two methods (&gt;50%) were observed for air-equivalent regions in the phantom simulation and the patient study.

A systems toxicology approach for identification of disruptions in cholesterol homeostasis after aggregated exposure to mixtures of perfluorinated compounds in humans.

Per- and polyfluoroalkyl substances (PFAS) are used in various household and industrial products. In humans, positive associations were reported between PFAS, including perfluorsulfonic acid and perfluorooctanoic acid, and cholesterol, a cardiometabolic risk factor. Animal studies show the opposite. Human-centered approaches are needed to better understand the effects of PFAS mixtures on cholesterol. Here, a systems toxicology approach is described, using a gene-centered cholesterol biokinetic model. PFAS exposure-gene expression relations from published data were introduced into the model. An existing PFAS physiologically based kinetic model was augmented with lung and dermal compartments and integrated with the cholesterol model to enable exposure-effect modeling. The final model was populated with data reflecting lifetime mixture exposure from: tolerable weekly intake values; the environment; high occupational exposures (ski waxing, PFAS industry). Results indicate that low level exposures (tolerable weekly intake, environmental) did not change cholesterol. In contrast, occupational exposures clearly resulted in internal PFAS exposure and disruption of cholesterol homeostasis, largely in line with epidemiological observations. Despite model limitations (eg, dynamic range, directionality), changes in cholesterol homeostasis were predicted for ski waxers, hitherto unknown from epidemiological studies. Here, future studies involving lipid metabolism could improve risk assessment.

Performance Evaluation of a Mechanical Test Lung Prototype for Lung Mechanics Research

Due to the inherent non-linearity and variability of the human respiratory system, predicting the physiological response of patients undergoing mechanical ventilation (MV) treatment is challenging. This unpredictability, both within and between patients, contributes to the lack of clear guidelines for optimising MV settings within standardised clinical protocols. A clinically realistic mechanical test lung would offer clinicians the opportunity to test MV settings to identify optimal configurations. However, there is currently no active test lung featuring a spontaneous breathing system and versatile, clinically realistic lung mechanics. This study presents a mechanical test lung prototype, comprising three subsystems the: 1) lung compartment; 2) airway; and 3) spontaneous breathing system. Multiple experiments demonstrate its ability to provide continuous lung elastance spanning 25 to 85 cmH2O/L and respiratory resistances ranging from 10 to 45 cmH2O·s/L. Further, it can simulate spontaneous breathing with diverse respiratory patterns, with high similarity compared to certified clinical test lungs across various scenarios, as well as clinical data.

1954. Dynamic PET facilitated Modeling and Novel Antibiotic Regimens for Tuberculous Meningitis due to Multidrug-Resistant Strains

1954. Dynamic PET facilitated Modeling and Novel Antibiotic Regimens for Tuberculous Meningitis due to Multidrug-Resistant Strains

Sox9 is associated with two distinct patterning events during snake lung morphogenesis

The evolutionary forces that allowed species adaptation to different terrestrial environments and led to great diversity in body shape and size required acquisition of innovative strategies of pattern formation during organogenesis. An extreme example is the formation of highly elongated viscera in snakes. What developmental patterning strategies allowed to overcome the space constraints of the snake's body to meet physiological demands? Here we show that the corn snake uses a Sox2-Sox9 developmental tool kit common to other species to generate and shape the lung in two phases. Initially Sox9 was found at low levels at the tip of the primary lung bud during outgrowth and elongation of the bronchial bud, without driving branching programs characteristic of mammalian lungs. Later, Sox9 induction is recapitulated in the formation of an extensive network of radial septae emerging along the elongated bronchial bud that generates the respiratory region. We propose that altogether these represent key patterning events for formation of both the respiratory faveolar and non-respiratory posterior compartments of the snake's lung.

Extracellular Vesicles From Mesenchymal Umbilical Cord Cells Exert Protection Against Oxidative Stress and Fibrosis in a Rat Model of Bronchopulmonary Dysplasia.

Oxidative stress and fibrosis are important stress responses that characterize bronchopulmonary dysplasia (BPD), a disease for which only a therapy but not a cure has been developed. In this work, we investigated the effects of mesenchymal stromal cells-derived extracellular vesicles (MSC-EVs) on lung and brain compartment in an animal model of hyperoxia-induced BPD. Rat pups were intratracheally injected with MSC-EVs produced by human umbilical cord-derived MSC, following the Good Manufacturing Practice-grade (GMP-grade). After evaluating biodistribution of labelled MSC-EVs in rat pups left in normoxia and hyperoxia, oxidative stress and fibrosis investigation were performed. Oxidative stress protection by MSC-EVs treatment was proved both in lung and in brain. The lung epithelial compartment ameliorated glycosaminoglycan and surfactant protein expression in MSC-EVs-injected rat pups compared to untreated animals. Pups under hyperoxia exhibited a fibrotic phenotype in lungs shown by increased collagen deposition and also expression of profibrotic genes. Both parameters were reduced by treatment with MSC-EVs. We established an in vitro model of fibrosis and another of oxidative stress, and we proved that MSC-EVs suppressed the induction of αSMA, influencing collagen deposition and protecting from the oxidative stress. In conclusion, intratracheal administration of clinical-grade MSC-EVs protect from oxidative stress, improves pulmonary epithelial function, and counteracts the development of fibrosis. In the future, MSC-EVs could represent a new cure to prevent the development of BPD.

Route of Francisella tularensis infection informs spatiotemporal metabolic reprogramming and inflammation in mice.

Route of exposure to pathogens can inform divergent disease pathogenesis and mortality rates. However, the features that contribute to these differences are not well established. Host metabolism has emerged as a critical element governing susceptibility and the metabolism of tissue exposure sites are unique. Therefore, specific metabolic niches may contribute to the course and outcome of infection depending on route of infection. In the current study, we utilized a combination of imaging and systems metabolomics to map the spatiotemporal dynamics of the host response to intranasal (i.n.) or intradermal (i.d.) infection of mice using the bacterium Francisella tularensis subsp tularensis (FTT). FTT causes lethal disease through these infection routes with similar inoculation doses and replication kinetics, which allowed for isolation of host outcomes independent of bacterial burden. We observed metabolic modifications that were both route dependent and independent. Specifically, i.d. infection resulted in early metabolic reprogramming at the site of infection and draining lymph nodes, whereas the lungs and associated draining lymph nodes were refractory to metabolic reprogramming following i.n. infection. Irrespective of exposure route, FTT promoted metabolic changes in systemic organs prior to colonization, and caused massive dysregulation of host metabolism in these tissues prior to onset of morbidity. Preconditioning infection sites towards a more glycolytic and pro-inflammatory state prior to infection exacerbated FTT replication within the lungs but not intradermal tissue. This enhancement of replication in the lungs was associated with the ability of FTT to limit redox imbalance and alter the pentose phosphate pathway. Together, these studies identify central metabolic features of the lung and dermal compartments that contribute to disease progression and identify potential tissue specific targets that may be exploited for novel therapeutic approaches.