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The disease origins of idiopathic pulmonary fibrosis (IPF), which occurs at higher rates in certain races/ethnicities, are not understood. The highest rates occur in white persons of European descent, particularly those with light skin, who are also susceptible to lysosomal organelle dysfunction of the skin leading to fibroproliferative disease . We had observed clinically that the vast majority of patients with IPF had light-colored eyes, suggesting a phenotypic characteristic.We pursued this observation through a research database from the USA Veterans Administration, a population that has a high occurrence of IPF due to predominance of elderly male smokers. Using this medical records database, which included facial photos, we compared the frequency of light (blue, green, hazel) and dark (light brown, brown) eyes among white patients diagnosed with IPF compared with a control group of lung granuloma only (no other radiologic evidence of interstitial lung disease).Light eye color was significantly more prevalent in patients with IPF than in the control group with lung granuloma [114/147 (77.6%) versus 129/263 (49.0%], p 0.001), indicating that light-colored eyes are a phenotype associated with IPF .We provide evidence that light eye color is predominant among white persons with IPF.

The ontogenetic composition of tissue-resident macrophages following injury, environmental exposure, or experimental depletion can be altered upon re-establishment of homeostasis. However, the impact of altered resident macrophage ontogenetic milieu on subsequent immune responses is poorly understood. Hence, we assessed the effect of macrophage ontogeny alteration following return to homeostasis on subsequent allergic airway responses to house dust mites (HDM). Using lineage tracing, we confirmed alveolar and interstitial macrophage ontogeny and their replacement by bone marrow-derived macrophages following LPS exposure. This alteration in macrophage ontogenetic milieu reduced allergic airway responses to HDM challenge. In addition, we defined a distinct population of resident-derived interstitial macrophages expressing allergic airway disease genes, located adjacent to terminal bronchi, and reduced by prior LPS exposure. These findings support that the ontogenetic milieu of pulmonary macrophages is a central factor in allergic airway responses and has implications for how prior environmental exposures impact subsequent immune responses and the development of allergy.

Hyperpolarized xenon 129 MRI and spectroscopy are sensitive to abnormal interstitial barrier uptake and red blood cell transfer in participants with nonspecific interstitial pneumonia.

Asthma is a common respiratory disease currently affecting more than 300 million worldwide and is characterized by airway inflammation, hyperreactivity, and remodeling. It is a heterogeneous disease consisting of corticosteroid-sensitive T-helper cell type 2-driven eosinophilic and corticosteroid-resistant, T-helper cell type 17-driven neutrophilic phenotypes. One pathway recently described to regulate asthma pathogenesis is cholesterol trafficking. Scavenger receptors, in particular SR-BI (scavenger receptor class B type I), are known to direct cellular cholesterol uptake and efflux. We recently defined SR-BI functions in pulmonary host defense; however, the function of SR-BI in asthma pathogenesis is unknown. To elucidate the role of SR-BI in allergic asthma, SR-BI-sufficient (SR-BI

RATIONALE: The development of novel therapies for idiopathic pulmonary fibrosis (IPF) has brought increased attention to the population burden of disease. However, little is known about the epidemiology of IPF among U.S. Veterans. OBJECTIVES: This study examines temporal trends in incidence and prevalence, patient characteristics, and risk factors associated with IPF among a national cohort of U.S. Veterans. METHODS: We used data from the Veterans Health Administration (VHA) electronic health record system to describe the incidence, prevalence, and geographic distribution of IPF between January 1, 2010, and December 31, 2019. We evaluated patient characteristics associated with IPF using multivariate logistic regression. RESULTS: Among 10.7 million Veterans who received care from the VHA between 2010 and 2019, 139,116 (1.26%) were diagnosed with IPF. Using a narrow case definition of IPF, the prevalence increased from 276 cases per 100,000 in 2010 to 725 cases per 100,000 in 2019. The annual incidence increased from 73 cases per 100,000 person-years in 2010 to 210 cases per 100,000 person-years in 2019. Higher absolute incidence and prevalence rates were noted when a broader case definition of IPF was used. Risk factors associated with IPF among Veterans included older age, White race, tobacco use, and rural residence. After accounting for interactions, the average marginal difference in IPF prevalence between males and females was small. There was significant geographic heterogeneity of disease across the United States. CONCLUSIONS: This study is the first comprehensive epidemiologic analysis of IPF among the U.S. Veteran population. The incidence and prevalence of IPF among Veterans has increased over the past decade. The effect of sex on risk of IPF was attenuated once accounting for other risk factors. The geographic distribution of disease is heterogeneous across the United States with rural residence associated with higher odds of IPF. The reasons for these trends deserve further study.

Background Recent studies demonstrate that antifibrotic drugs previously reserved for idiopathic pulmonary fibrosis (IPF) may slow progression in other interstitial lung diseases (ILDs), creating an urgent need for tools that can sensitively assess disease activity, progression, and therapy response across ILDs. Hyperpolarized xenon 129 (

Ozone (O3) is a criteria air pollutant known to increase the morbidity and mortality of cardiopulmonary diseases. This occurs through a pulmonary inflammatory response characterized by increased recruitment of immune cells into the airspace, pro-inflammatory cytokines, and pro-inflammatory lipid mediators. Recent evidence has demonstrated sex-dependent differences in the O3-induced pulmonary inflammatory response. However, it is unknown if this dimorphic response is evident in pulmonary lipid mediator metabolism. We hypothesized that there are sex-dependent differences in lipid mediator production following acute O3 exposure. Male and female C57BL/6J mice were exposed to 1 part per million O3 for 3 h and were necropsied at 6 or 24 h following exposure. Lung lavage was collected for cell differential and total protein analysis, and lung tissue was collected for mRNA analysis, metabololipidomics, and immunohistochemistry. Compared with males, O3-exposed female mice had increases in airspace neutrophilia, neutrophil chemokine mRNA, pro-inflammatory eicosanoids such as prostaglandin E2, and specialized pro-resolving mediators (SPMs), such as resolvin D5 in lung tissue. Likewise, precursor fatty acids (arachidonic and docosahexaenoic acid; DHA) were increased in female lung tissue following O3 exposure compared with males. Experiments with ovariectomized females revealed that loss of ovarian hormones exacerbates pulmonary inflammation and injury. However, eicosanoid and SPM production were not altered by ovariectomy despite depleted pulmonary DHA concentrations. Taken together, these data indicate that O3 drives an increased pulmonary inflammatory and bioactive lipid mediator response in females. Furthermore, ovariectomy increases susceptibility to O3-induced pulmonary inflammation and injury, as well as decreases pulmonary DHA concentrations.

The lung mucosa functions as a principal barrier between the body and inhaled environmental irritants and pathogens. Precise and targeted surveillance mechanisms are required at this lung-environment interface to maintain homeostasis and preserve gas exchange. This is performed by the innate immune system, a germline-encoded system that regulates initial responses to foreign irritants and pathogens. Environmental pollutants, such as particulate matter (PM), Ozone (O(3)), and other products of combustion (NO(2), SO(3), etc.) both stimulate and disrupt the function of the innate immune system of the lung, leading to the potential for pathologic consequences. PURPOSE OF REVIEW: The purpose of this review is to explore recent discoveries and investigations into the role of the innate immune system in responding to environmental exposures. This focuses on mechanisms by which the normal function of the innate immune system is modified by environmental agents leading to disruptions in respiratory function. RECENT FINDINGS: This is a narrative review of mechanisms of pulmonary innate immunity and the impact of environmental exposures on these responses. Recent findings highlighted in this review are categorized by specific components of innate immunity including epithelial function, macrophages, pattern recognition receptors, and the microbiome. Overall, the review supports broad impacts of environmental exposures to alterations to normal innate immune functions and have important implications for incidence and exacerbations of lung disease. SUMMARY: The innate immune system plays a critical role in maintaining pulmonary homeostasis in response to inhaled air pollutants. As many of these agents are unable to be mitigated, understanding their mechanistic impact is critical to develop future interventions to limit their pathologic consequences.

Defining responses of the structural and immune cells in biologic systems is critically important to understanding disease states and responses to injury. This requires accurate and sensitive methods to define cell types in organ systems. The principal method to delineate the cell populations involved in these processes is flow cytometry. Although researchers increasingly use flow cytometry, technical challenges can affect its accuracy and reproducibility, thus significantly limiting scientific advancements. This challenge is particularly critical to lung immunology, as the lung is readily accessible and therefore used in preclinical and clinical studies to define potential therapeutics. Given the importance of flow cytometry in pulmonary research, the American Thoracic Society convened a working group to highlight issues and technical challenges to the performance of high-quality pulmonary flow cytometry, with a goal of improving its quality and reproducibility.

Smoking and human immunodeficiency virus 1 (HIV-1) infection are risk factors for chronic obstructive pulmonary disease (COPD), which is among the most common comorbid conditions in people living with HIV-1. HIV-1 infection leads to persistent expansion of CD8(+) T cells, and CD8(+) T cell–mediated inflammation has been implicated in COPD pathogenesis. In this study, we investigated the effects of HIV-1 infection and smoking on T-cell dynamics in patients at risk of COPD. BAL fluid, endobronchial brushings, and blood from HIV-1 infected and uninfected nonsmokers and smokers were analyzed by flow cytometry, and lungs were imaged by computed tomography. Chemokines were measured in BAL fluid, and CD8(+) T-cell chemotaxis in the presence of cigarette smoke extract was assessed in vitro. HIV-1 infection increased CD8(+) T cells in the BAL fluid, but this increase was abrogated by smoking. Smokers had reduced BAL fluid concentrations of the T cell–recruiting chemokines CXCL10 and CCL5, and cigarette smoke extract inhibited CXCL10 and CCL5 production by macrophages and CD8(+) T-cell transmigration in vitro. In contrast to the T cells in BAL fluid, CD8(+) T cells in endobronchial brushings were increased in HIV-1–infected smokers, which was driven by an accumulation of effector memory T cells in the airway mucosa and an increase in tissue-resident memory T cells. Mucosal CD8(+) T-cell numbers inversely correlated with lung aeration, suggesting an association with inflammation and remodeling. HIV-1 infection and smoking lead to retention of CD8(+) T cells within the airway mucosa.

Hyperpolarized (129)Xe MRI has emerged as a novel means to evaluate pulmonary function via 3D mapping of ventilation, interstitial barrier uptake, and RBC transfer. However, the physiological interpretation of these measurements has yet to be firmly established. Here, we propose a model that uses the three components of (129)Xe gas-exchange MRI to estimate accessible alveolar volume (V(A)), membrane conductance, and capillary blood volume contributions to DL(CO). (129)Xe ventilated volume (VV) was related to V(A) by a scaling factor k(V) = 1.47 with 95% confidence interval [1.42, 1.52], relative (129)Xe barrier uptake (normalized by the healthy reference value) was used to estimate the membrane-specific conductance coefficient k(B) = 10.6 [8.6, 13.6] mL/min/mmHg/L, whereas normalized RBC transfer was used to calculate the capillary blood volume-specific conductance coefficient k(R) = 13.6 [11.4, 16.7] mL/min/mmHg/L. In this way, the barrier and RBC transfer per unit volume determined the transfer coefficient K(CO), which was then multiplied by image-estimated V(A) to obtain DL(CO). The model was built on a cohort of 41 healthy subjects and 101 patients with pulmonary disorders. The resulting (129)Xe-derived DL(CO) correlated strongly (R(2) = 0.75, P < 0.001) with the measured values, a finding that was preserved within each individual disease cohort. The ability to use (129)Xe MRI measures of ventilation, barrier uptake, and RBC transfer to estimate each of the underlying constituents of DL(CO) clarifies the interpretation of these images while enabling their use to monitor these aspects of gas exchange independently and regionally. NEW & NOTEWORTHY The diffusing capacity for carbon monoxide (DL(CO)) is perhaps one of the most comprehensive physiological measures used in pulmonary medicine. Here, we spatially resolve and estimate its key components—accessible alveolar volume, membrane, and capillary blood volume conductances—using hyperpolarized (129)Xe MRI of ventilation, interstitial barrier uptake, and red blood cell transfer. This image-derived DL(CO) correlates strongly with measured values in 142 subjects with a broad range of pulmonary disorders.

BackgroundIncreased exposure to Ozone (O3) is associated with adverse health effects in individuals afflicted with respiratory diseases. Surfactant protein-A (SP-A), encoded bySP-A1andSP-A2, is the largest protein component in pulmonary surfactant and is functionally impaired by O3-oxidation.ObjectiveWe used humanized SP-A2 transgenic mice with allelic variation corresponding to a glutamine (Q) to lysine (K) amino acid substitution at position 223 in the lectin domain to determine the impact of this genetic variation in regards to O3exposure.MethodsMice were exposed to 2ppm O3or Filtered Air (FA) for 3 hours and 24 hrs post-challenge pulmonary function tests and other parameters associated with inflammation were assessed in the bronchoalveolar lavage (BAL) fluid and lung tissue. Additionally, mouse tracheal epithelial cells were cultured and TEER measurements recorded for each genotype to determine baseline epithelial integrity.ResultsCompared to FA, O3exposure led to significantly increased sensitivity to methacholine challenge in all groups of mice. SP-A2 223Q variant mice were significantly protected from O3-induced AHR compared to SP-A-/-and SP-A2 223K mice. Neutrophilia was observed in all genotypes of mice post O3-exposure, however, SP-A2 223Q mice had a significantly lower percentage of neutrophils compared to SP-A-/-mice. Albumin levels in BAL were unchanged in O3-exposed SP-A2 223Q mice compared to their FA controls, while levels were significantly increased in all other genotypes of O3-exposed mice. SP-A 223Q MTECS has significant higher TEER values than all other genotypes, and WT MTECS has significantly higher TEER than the SP-A KO and SP-A 223K MTECS.SignificanceTaken together, our study suggests that expression of a glutamine (Q) as position 223 in SP-A2, as opposed to expression of lysine (K), is more protective in acute exposures to ozone and results in attenuated O3-induced AHR, neutrophilia, and vascular permeability.

Rationale: Macrophages are the most abundant immune cell in the alveoli and small airways and are traditionally viewed as a homogeneous population during health. Whether distinct subsets of airspace macrophages are present in healthy humans is unknown. Single-cell RNA sequencing allows for examination of transcriptional heterogeneity between cells and between individuals. Understanding the conserved repertoire of airspace macrophages during health is essential to understanding cellular programing during disease. Objectives: We sought to determine the transcriptional heterogeneity of human cells obtained from BAL of healthy adults. Methods: Ten subjects underwent bronchoscopy with BAL. Cells from lavage were subjected to single-cell RNA sequencing. Unique cell populations and putative functions were identified. Transcriptional profiles were compared across individuals. Measurements and Main Results: We identify two novel subgroups of resident airspace macrophages—defined by proinflammatory and metallothionein gene expression profiles. We define subsets of monocyte-like cells and compare them with peripheral blood mononuclear cells. Finally, we compare global macrophage and monocyte programing between males and females. Conclusions: Healthy human airspaces contain multiple populations of myeloid cells that are highly conserved between individuals and between sexes. Resident macrophages make up the largest population and include novel subsets defined by inflammatory and metal-binding profiles. Monocyte-like cells within the airspaces are transcriptionally aligned with circulating blood cells and include a rare population defined by expression of cell–matrix interaction genes. This study is the first to delineate the conserved heterogeneity of airspace immune cells during health and identifies two previously unrecognized macrophage subsets.

Background: Epidemiological studies support the hypothesis that diabetes alters pulmonary responses to air pollutants like ozone (O3). The mechanism(s) underlying these associations and potential links among diabetes, O3, and lung inflammation and remodeling are currently unknown. Objectives: The goal was to determine whether pulmonary responses to repetitive ozone exposures are exacerbated in murine strains that are hyperglycemic and insulin resistant. Methods: Normoglycemic and insulin-sensitive C57BL/6J mice; hyperglycemic, but mildly insulin-resistant, KK mice; and hyperglycemic and markedly insulin-resistant KKAy mice were used for ozone exposure studies. All animals were exposed to filtered air (FA) or repetitive ozone (0.5 ppm O3, 4 h/d, for 13 consecutive weekdays). Tissue analysis was performed 24 h following the final exposure. This analysis included bronchoalveolar lavage (BAL) for cell and fluid analysis, and tissue for pathology, immunohistology, mRNA, and hydroxyproline. Results: Following repetitive O3 exposure, higher bronchoalveolar lavage fluid inflammatory cells were observed in all mice (KKAy>KK>C57BL/6), with a notable influx of neutrophils and eosinophils in KK and KKAy mice. Although the lungs of O3-exposed C57BL/6J and KK mice had minimal centriacinar histological changes without fibrosis, the lungs of O3-exposed KKAy mice contained marked epithelial hyperplasia in proximal alveolar ducts and adjacent alveoli with associated centriacinar fibrosis. Fibrosis in O3-exposed KKAy lungs was confirmed with immunohistochemistry, tissue hydroxyproline content, and tissue mRNA expression of fibrosis-associated genes (Ccl11, Il13, and Mmp12). Immunofluorescence staining and confocal microscopy revealed alterations in the structure and composition of the airway and alveolar epithelium in regions of fibrosis. Discussion: Our results demonstrate that in diabetic animal strains repetitive ambient ozone exposure led to early and exaggerated pulmonary inflammation and remodeling. Changes in distal and interstitial airspaces and the activation of Th2 inflammatory and profibrotic pathways in experimental animals provide a preliminary, mechanistic framework to support the emerging epidemiological associations among air pollution, diabetes, and lung disease. https://doi.org/10.1289/EHP7255

Rationale: Interstitial macrophages (IMs) and airspace macrophages (AMs) play critical roles in lung homeostasis and host defense, and are central to the pathogenesis of a number of lung diseases. However, the absolute numbers of macrophages and the precise anatomic locations they occupy in the healthy human lung have not been quantified. Objectives: To determine the precise number and anatomic location of human pulmonary macrophages in nondiseased lungs and to quantify how this is altered in chronic cigarette smokers. Methods: Whole right upper lobes from 12 human donors without pulmonary disease (6 smokers and 6 nonsmokers) were evaluated using design-based stereology. CD206 (cluster of differentiation 206)-positive/CD43(+) AMs and CD206(+)/CD43(−) IMs were counted in five distinct anatomical locations using the optical disector probe. Measurements and Main Results: An average of 2.1 × 10(9) IMs and 1.4 × 10(9) AMs were estimated per right upper lobe. Of the AMs, 95% were contained in diffusing airspaces and 5% in airways. Of the IMs, 78% were located within the alveolar septa, 14% around small vessels, and 7% around the airways. The local density of IMs was greater in the alveolar septa than in the connective tissue surrounding the airways or vessels. The total number and density of IMs was 36% to 56% greater in the lungs of cigarette smokers versus nonsmokers. Conclusions: The precise locations occupied by pulmonary macrophages were defined in nondiseased human lungs from smokers and nonsmokers. IM density was greatest in the alveolar septa. Lungs from chronic smokers had increased IM numbers and overall density, supporting a role for IMs in smoking-related disease.

Ozone causes airway hyperresponsiveness, a defining feature of asthma. We have reported that the gut microbiome contributes to sex differences in ozone-induced airway hyperresponsiveness. Altering dietary fiber affects the gut microbiome. The purpose of this study was to determine the effects of dietary fiber on pulmonary responses to ozone and whether these effects differ by sex. We fed male and female mice fiber-free diets or diets enriched in one of two types of dietary fiber, cellulose and pectin, for 3 days before ozone exposure. Compared with control diets or pectin-enriched diets, cellulose-enriched diets attenuated ozone-induced airway hyperresponsiveness in male but not female mice. In contrast, fiber-free diets augmented responses to ozone in female but not male mice. Analysis of 16S rRNA sequencing of fecal DNA also indicated sex differences in the impact of dietary fiber on the gut microbiome and identified bacterial taxa that were associated with ozone-induced airway hyperresponsiveness. Our data suggest that microbiome-based therapies such as prebiotics may provide an alternative therapeutic strategy for air pollution–triggered asthma, but they indicate that such therapeutics may need to be tailored differently for males and females.

Lung disease causes significant morbidity and mortality, and is exacerbated by environmental injury, for example through lipopolysaccharide (LPS) or ozone (O3). Toll-like receptors (TLRs) orchestrate immune responses to injury by recognizing pathogen- or danger-associated molecular patterns. TLR4, the prototypic receptor for LPS, also mediates inflammation after O3, triggered by endogenous hyaluronan. Regulation of TLR4 signaling is incompletely understood. TLR5, the flagellin receptor, is expressed in alveolar macrophages, and regulates immune responses to environmental injury. Using in vivo animal models of TLR4-mediated inflammations (LPS, O3, hyaluronan), we show that TLR5 impacts the in vivo response to LPS, hyaluronan and O3. We demonstrate that immune cells of human carriers of a dominant negative TLR5 allele have decreased inflammatory response to O3 exposure ex vivo and LPS exposure in vitro. Using primary murine macrophages, we find that TLR5 physically associates with TLR4 and biases TLR4 signaling towards the MyD88 pathway. Our results suggest an updated paradigm for TLR4/TLR5 signaling., eLife digest Immune cells in the lung help guard against infections. On the surface of these cells are proteins called TLR receptors that recognize dangerous molecules or DNA from disease-causing microbes such as bacteria. When the immune cells detect these invaders, the TLR receptors spring into action and trigger an inflammatory response to destroy the microbes. This inflammation usually helps the lung clear infections. But it can also be harmful and damage the lung, for example when inflammation is caused by non-infectious substances such as pollutants in the atmosphere. There are several TLR receptors that each recognize a specific molecule. In 2010, researchers showed that the receptor TLR4 is responsible for causing inflammation in the lung after exposure to pollution. Another receptor called TLR5 also helps activate the immune response in the lung. But it was unclear whether this receptor also plays a role in pollution-linked lung damage. Now, Hussain, Johnson, Sciurba et al. – including one of the researchers involved in the 2010 study – have investigated the role of TLR5 in immune cells from the lungs of humans and mice. The experiments showed that TLR5 works together with TLR4 and helps trigger an inflammatory response to both pollutants and bacteria. Hussain et al. found that people lacking a working TLR5 receptor (which make up 3–10% of the population) are less likely to experience lung inflammation when exposed to pollution or bacterial proteins that activate TLR4. These findings suggest that people without TLR5 may be protected from pollution-induced lung injury. Further research into the role of TLR5 could help develop genetic tests for identifying people who are more sensitive to damage from pollution. This information could then be used to determine the likelihood of a patient experiencing certain lung diseases.

RATIONALE Patients with asthma demonstrate depletion of the endogenous bronchodilator GSNO and upregulation of GSNOR. OBJECTIVES An exploratory proof of concept clinical study of N6022 in mild asthma to determine the potential bronchoprotective effects of GSNOR inhibition. Mechanistic studies aimed to provide translational evidence of effect. METHODS Fourteen mild asthma patients were treated with intravenous N6022 (5 mg) or placebo and observed for 7 days, with repeated assessments of the provocative dose of methacholine causing a 20% fall in FEV1 (methacholine PC20 FEV1), followed by a washout period and crossover treatment and observation. In vitro studies in isolated eosinophils investigated the effect of GSNO and N6022 on apoptosis. MEASUREMENTS AND MAIN RESULTS This was a negative trial as it failed to reach its primary endpoint, which was change from baseline in methacholine PC20 FEV1 at 24 h. However, our exploratory analysis demonstrated significantly more two dose-doubling increases in PC20 FEV1 for N6022 compared with placebo (21% vs 6%, P

Exposure to ozone (O(3)) induces lung injury, pulmonary inflammation, and alters lipid metabolism. During tissue inflammation, specialized pro-resolving lipid mediators (SPMs) facilitate the resolution of inflammation. SPMs regulate the pulmonary immune response during infection and allergic asthma; however, the role of SPMs in O(3)-induced pulmonary injury and inflammation is unknown. We hypothesize that O(3) exposure induces pulmonary inflammation by reducing SPMs. To evaluate this, male C57Bl/6J mice were exposed to filtered air (FA) or 1 ppm O(3) for 3 h and necropsied 24 h after exposure. Pulmonary injury/inflammation was determined by bronchoalveolar lavage (BAL) differentials, protein, and lung tissue cytokine expression. SPMs were quantified by liquid chromatography tandem mass spectrometry and SPM receptors leukotriene B(4) receptor 1 (BLT-1), formyl peptide receptor 2 (ALX/FPR2), chemokine-like receptor 1 (ChemR23), and SPM-generating enzyme (5-LOX and 12/15-LOX) expression were measured by real time PCR. 24 h post-O(3) exposure, BAL PMNs and protein content were significantly increased compared to FA controls. O(3)-induced lung inflammation was associated with significant decreases in pulmonary SPM precursors (14-HDHA, 17-HDHA), the SPM PDX, and in pulmonary ALX/FPR2, ChemR23, and 12/15-LOX expression. Exogenous administration of 14-HDHA, 17-HDHA, and PDX 1 h prior to O(3) exposure rescued pulmonary SPM precursors/SPMs, decreased proinflammatory cytokine and chemokine expression, and decreased BAL macrophages and PMNs. Taken together, these data indicate that O(3)-mediated SPM reductions may drive O(3)-induced pulmonary inflammation.

Elevated ambient temperatures and extreme weather events have increased the incidence of wildfires world-wide resulting in increased wood smoke particle (WSP). Epidemiologic data suggests that WSP exposure associates with exacerbations of respiratory diseases, and with increased respiratory viral infections. To assess the impact of WSP exposure on host response to viral pneumonia, we performed WSP exposures in rodents followed by infection with mouse adapted influenza (HINI-PR8). C57BL/6 male mice aged 6–8 weeks were challenged with WSP or PBS by oropharyngeal aspiration in acute (single dose) or sub-acute exposures (day 1, 3, 5, 7 and 10). Additional groups underwent sub-acute exposure followed by infection by influenza or heat-inactivated (HI) virus. Following exposures/infection, bronchoalveolar lavage (BAL) was performed to assess for total cell counts/differentials, total protein, protein carbonyls and hyaluronan. Lung tissue was assessed for viral counts by real time PCR. When compared to PBS, acute WSP exposure associated with an increase in airspace macrophages. Alternatively, sub-acute exposure resulted in a dose dependent increase in airspace neutrophils. Sub-acute WSP exposure followed by influenza infection was associated with improved respiratory viral outcomes including reduced weight loss and increased blood oxygen saturation, and decreased protein carbonyls and viral titers. Flow cytometry demonstrated dynamic changes in pulmonary macrophage and T cell subsets based on challenge with WSP and influenza. This data suggests that sub-acute WSP exposure can improve host response to acute influenza infection.

The innate immune components that modulate allergic contact hypersensitivity (CHS) responses are poorly defined. Using human skin from contact dermatitis patients and a mouse model of CHS, we find that hapten allergens disrupt the Arginase1 (Arg1) and inducible NO synthase (iNOS) dynamic in monocytes/macrophages (mono/MΦ), which renders those cells ineffectual in suppressing skin inflammation. Mice lacking Arg1 in MΦ develop increased CHS characterized by elevated ear thickening, mono/MΦ−dominated dermal inflammation, and increased iNOS and IL-6 expression compared with control mice. Treatment of Arg1flox/flox; LysMCre+/− mice with a selective NOS inhibitor or knockout of Nos2, encoding iNOS, significantly ameliorates CHS. Our findings suggest a critical role for Arg1 in mono/MΦ in suppressing CHS through dampening Nos2 expression. These results support that increasing Arg1 may be a potential therapeutic avenue in treating allergic contact dermatitis.

Lung disease causes significant morbidity and mortality, and is exacerbated by environmental injury, e.g. through lipopolysaccharide (LPS) or ozone (O3). Toll-like receptors (TLRs) orchestrate immune responses to injury by recognizing pathogen- or danger-associated molecular patterns. TLR4, the prototypic receptor for LPS, also mediates inflammation after O3, triggered by endogenous hyaluronan. Regulation of TLR4 signaling is incompletely understood. TLR5, the flagellin receptor, is expressed in alveolar macrophages, and regulates immune responses to environmental injury. Using in vivo animal models of TLR4-mediated inflammations (LPS, O3, hyaluronan), we show that TLR5 impacts the in vivo response to LPS, hyaluronan and O3. We demonstrate that immune cells of human carriers of a dominant negative TLR5 allele have decreased inflammatory response to O3 exposure ex vivo and LPS exposure in vitro. Using primary murine macrophages, we find that TLR5 physically associates with TLR4 and biases TLR4 signaling towards the MyD88 pathway. Our results suggest an updated paradigm for TLR4/TLR5 signaling.

Objective: Provide information for pharmacists on idiopathic pulmonary fibrosis (IPF) and its treatment. Study Selection and Data Extraction: All articles with data from randomized controlled trials of nintedanib or pirfenidone were reviewed. Data Synthesis: IPF is a progressive and ultimately fatal interstitial lung disease characterized by decline in lung function and worsening dyspnea. It is uncommon and mainly occurs in individuals aged >60 years, particularly men with a history of smoking. Nintedanib and pirfenidone were approved in the United States for the treatment of IPF in 2014 and received conditional recommendations in the 2015 American Thoracic Society/European Respiratory Society/Japanese Respiratory Society/Latin American Thoracic Association treatment guidelines. These drugs slow the progression of IPF by reducing the rate of decline in lung function. Their adverse event profile is characterized mainly by gastrointestinal events, which can be managed through dose adjustment and symptom management. Management of IPF should also include smoking cessation, vaccinations, and supportive care such as patient education, pulmonary rehabilitation, and the use of supplemental oxygen as well as optimizing the management of comorbidities. Relevance to Patient Care and Clinical Practice: This review provides clinical pharmacists with information on the course of IPF, what can be expected of current treatments, and how to help patients manage their drug therapy. Conclusions: IPF is a progressive disease, but treatments are available that can slow the progression of the disease. Clinical pharmacists can play an important role in the care of patients with IPF through patient education, monitoring medication compliance and safety, ensuring drugs for comorbidities are optimized, and preventive strategies such as immunizations.

Radiation–induced pulmonary fibrosis (RTPF) is a progressive, serious condition in many subjects treated for thoracic malignancies or after accidental nuclear exposure. No biomarker exists for identifying the irradiated subjects most susceptible to pulmonary fibrosis (PF). Previously, we determined that gastrin-releasing peptide (GRP) was elevated within days after birth in newborns exposed to hyperoxia who later developed chronic lung disease. The goal of the current study was to test whether radiation (RT) exposure triggers GRP release in mice and whether this contributes to RTPF in vivo. We determined urine GRP levels and lung GRP immunostaining in mice 0 to 24 after post-thoracic RT (15 Gy). Urine GRP levels were significantly elevated between 24 hours post-RT; GRP-blocking monoclonal antibody 2A11, given minutes post-RT, abrogated urine GRP levels by 6 to 12 hours and also altered phosphoprotein signaling pathways at 24 hours post-RT. Strong extracellular GRP immunostaining was observed in lung at 6 hours post-RT. Mice given one dose of GRP monoclonal antibody 2A11 24 hours post-RT had significantly reduced myofibroblast accumulation and collagen deposition 15 weeks later, indicating protection against lung fibrosis. Therefore, elevation of urine GRP could be predictive of RTPF development. In addition, transient GRP blockade could mitigate PF in normal lung after therapeutic or accidental RT exposure.

Sex differences clearly exist in incidence, susceptibility, and severity of airway disease and in pulmonary responses to air pollutants such as ozone (O3). Prior rodent O3 exposure studies demonstrate sex-related differences in the expression of lung inflammatory mediators and signaling. However, whether or not sex modifies O3-induced airway physiologic responses remains less explored. To address this, we exposed 8- to 10-week-old male and female C57BL/6 mice to either 1 or 2 ppm O3 or filtered air (FA) for 3 h. At 12, 24, 48, and 72 h following exposure, we assessed airway hyperresponsiveness to methacholine (MCh), bronchoalveolar lavage fluid cellularity, cytokines and total protein/albumin, serum progesterone, and whole lung immune cells by flow cytometry. Male mice generated consistent airway hyperresponsiveness to MCh at all time points following exposure. Alternatively, females had less consistent airway physiologic responses to MCh, which were more variable between individual experiments and did not correlate with serum progesterone levels. Bronchoalveolar lavage fluid total cells peaked at 12 h and were persistently elevated through 72 h. At 48 h, bronchoalveolar lavage cells were greater in females versus males. Bronchoalveolar lavage fluid cytokines and total protein/albumin increased following O3 exposure without sex differences. Flow cytometry of whole lung tissue identified dynamic O3-induced immune cell changes also independent of sex. Our results indicate sex differences in acute O3-induced airway physiology responses and airspace influx without significant difference in other injury and inflammation measures. This study highlights the importance of considering sex as a biological variable in acute O3-induced airway physiology responses.

Background The epidemiology of Interstitial Lung Diseases (ILD) in the Veterans Health Administration (VHA) is presently unknown. Research question Describe the incidence/prevalence, clinical characteristics, and outcomes of ILD patients within the Veteran’s Administration Mid-Atlantic Health Care Network (VISN6). Study design and methods A multi-center retrospective cohort study was performed of veterans receiving hospital or outpatient ILD care from January 1, 2008 to December 31st, 2015 in six VISN6 facilities. Patients were identified by at least one visit encounter with a 515, 516, or other ILD ICD-9 code. Demographic and clinical characteristics were summarized using median, 25th and 75th percentile for continuous variables and count/percentage for categorical variables. Characteristics and incidence/prevalence rates were summarized, and stratified by ILD ICD-9 code. Kaplan Meier curves were generated to define overall survival. Results 3293 subjects met the inclusion criteria. 879 subjects (26%) had no evidence of ILD following manual medical record review. Overall estimated prevalence in verified ILD subjects was 256 per 100,000 people with a mean incidence across the years of 70 per 100,000 person-years (0.07%). The prevalence and mean incidence when focusing on people with an ILD diagnostic code who had a HRCT scan or a bronchoscopic or surgical lung biopsy was 237 per 100,000 people (0.237%) and 63 per 100,000 person-years respectively (0.063%). The median survival was 76.9 months for 515 codes, 103.4 months for 516 codes, and 83.6 months for 516.31. Interpretation This retrospective cohort study defines high ILD incidence/prevalence within the VA. Therefore, ILD is an important VA health concern.

Previous studies of the lung microbiome have focused on characterizing the community and attempts to understand the role of community membership concerning disease or exposures such as cigarette smoke. However, we still lack an understanding of two critical aspects of the lung microbiome: the origin of the community members and their fate. As we continue to better understand how the lung microbiome influences human health, it is essential to determine how the environment shapes the lung microbiome membership. Using a pig model, we explored the relationship that the surrounding environment has on the resident lung bacteria by collecting environmental samples (soil, air, water, feed) to compare with lung samples (swab, lavage, and tissue). Results suggest that airborne bacteria make up the highest portion of the lung microbiome. Furthermore, bacteria from samples taken from the bronchioles can be correctly identified by which farm they originated, whereas those from alveolar samples are indistinguishable. The findings suggest that while the environment may shape the microbiome of the bronchioles, a distinct community exists within the alveoli. Our findings expand upon the current understanding of the lung microbiome and provide a model of how microbial communities within the lung relate to their surrounding environment.