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Background Interstitial lung abnormalities (ILA) may represent undiagnosed early-stage or subclinical interstitial lung disease (ILD). ILAs are often observed incidentally in patients who subsequently develop clinically overt ILD. There is limited information on consensus definitions for, and the appropriate evaluation of, ILA. Early recognition of patients with ILD remains challenging, yet critically important. Expert consensus could inform early recognition and referral. Research Question Can consensus-based expert recommendations be identified to guide clinicians in the recognition, referral, and follow-up of patients with or at risk of developing early ILDs? Study Design and Methods Pulmonologists and radiologists with expertise in ILD participated in two iterative rounds of surveys. The surveys aimed to establish consensus regarding ILA reporting, identification of patients with ILA, and identification of populations that might benefit from screening for ILD. Recommended referral criteria and follow-up processes were also addressed. Threshold for consensus was defined a priori as ≥ 75% agreement or disagreement. Results Fifty-five experts were invited and 44 participated; consensus was reached on 39 of 85 questions. The following clinically important statements achieved consensus: honeycombing and traction bronchiectasis or bronchiolectasis indicate potentially progressive ILD; honeycombing detected during lung cancer screening should be reported as potentially significant (eg, with the Lung CT Screening Reporting and Data System “S-modifier” [which indicates clinically significant or potentially significant noncancer findings]), recommending referral to a pulmonologist in the radiology report; high-resolution CT imaging and full pulmonary function tests should be ordered if nondependent subpleural reticulation, traction bronchiectasis, honeycombing, centrilobular ground-glass nodules, or patchy ground-glass opacity are observed on CT imaging; patients with honeycombing or traction bronchiectasis should be referred to a pulmonologist irrespective of FVC and diffusion capacity values; and patients with systemic sclerosis should be screened with pulmonary function tests for early-stage ILD. Interpretation Guidance for identifying clinically relevant ILA, with subsequent referral and follow-up, was established. These results lay the foundation for developing practical guidance on managing patients with ILA.

Rationale: Several new drugs for idiopathic pulmonary fibrosis (IPF) are in development. Tools are needed to assess whether these drugs benefit patients on outcomes that matter most to them. Health-related quality of life (HRQL) is one such outcome. It is influenced by many factors, but symptoms and their impacts are two strong drivers. Objectives: To develop a questionnaire to assess symptoms, disease impacts, and HRQL specifically for patients with IPF. Methods: Working with the U.S. Food and Drug Administration through the Drug Development Tool Qualification process, focus groups, concept elicitation, and cognitive debriefing interviews were conducted to inform the development of a 44-item pilot questionnaire. The pilot paper-and-pen questionnaire was migrated to an equivalent electronic version and field-tested in a 14-day study. Response data were subjected to psychometric testing, including exploratory factor analysis, item calibration using item response theory models, test-retest reliability, and validity testing. Measurements and Main Results: A total of 125 patients with IPF (62.4% men) completed the longitudinal study. The mean ± SD age of the cohort was 69 ± 7.60 years, and the mean FVC% predicted was 71 ± 20.0. After factor and item analyses, 35 items were retained, and these comprise the two modules (symptoms and impacts) of the Living with IPF (L-IPF) questionnaire. The L-IPF yields five scales demonstrating good psychometric properties, including correlation with concurrently collected FVC% predicted and the ability to discriminate between patients with differing levels of IPF severity. Conclusions: The L-IPF is a new questionnaire that assesses symptoms, disease impacts, and HRQL in patients with IPF.

Fibrosis is characterized by fibroblast activation, leading to matrix remodeling culminating in a stiff, type I collagen–rich fibrotic matrix. Alveolar epithelial cell (AEC) apoptosis is also a maj...

Chronic lung diseases such as idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD) are associated with changes in extracellular matrix (ECM) composition and abundance affecting the mechanical properties of the lung. This study aimed to generate ECM hydrogels from control, severe COPD [Global Initiative for Chronic Obstructive Lung Disease (GOLD) IV], and fibrotic human lung tissue and evaluate whether their stiffness and viscoelastic properties were reflective of native tissue. For hydrogel generation, control, COPD GOLD IV, and fibrotic human lung tissues were decellularized, lyophilized, ground into powder, porcine pepsin solubilized, buffered with PBS, and gelled at 37°C. Rheological properties from tissues and hydrogels were assessed with a low-load compression tester measuring the stiffness and viscoelastic properties in terms of a generalized Maxwell model representing phases of viscoelastic relaxation. The ECM hydrogels had a greater stress relaxation than tissues. ECM hydrogels required three Maxwell elements with slightly faster relaxation times (τ) than that of native tissue, which required four elements. The relative importance (Ri) of the first Maxwell element contributed the most in ECM hydrogels, whereas for tissue the contribution was spread over all four elements. IPF tissue had a longer-lasting fourth element with a higher Ri than the other tissues, and IPF ECM hydrogels did require a fourth Maxwell element, in contrast to all other ECM hydrogels. This study shows that hydrogels composed of native human lung ECM can be generated. Stiffness of ECM hydrogels resembled that of whole tissue, while viscoelasticity differed.

Objectives To establish a framework by which experts define disease subsets in systemic sclerosis associated interstitial lung disease (SSc-ILD). Methods A conceptual framework for subclinical, clinical and progressive ILD was provided to 83 experts, asking them to use the framework and classify actual SSc-ILD patients. Each patient profile was designed to be classified by at least four experts in terms of severity and risk of progression at baseline; progression was based on 1-year follow-up data. A consensus was reached if ≥75% of experts agreed. Experts provided information on which items were important in determining classification. Results Forty-four experts (53%) completed the survey. Consensus was achieved on the dimensions of severity (75%, 60 of 80 profiles), risk of progression (71%, 57 of 80 profiles) and progressive ILD (60%, 24 of 40 profiles). For profiles achieving consensus, most were classified as clinical ILD (92%), low risk (54%) and stable (71%). Severity and disease progression overlapped in terms of framework items that were most influential in classifying patients (forced vital capacity, extent of lung involvement on high resolution chest CT [HRCT]); risk of progression was influenced primarily by disease duration. Conclusions Using our proposed conceptual framework, international experts were able to achieve a consensus on classifying SSc-ILD patients along the dimensions of disease severity, risk of progression and progression over time. Experts rely on similar items when classifying disease severity and progression: a combination of spirometry and gas exchange and quantitative HRCT.

Pulmonary fibrosis is a pathologic process associated with scarring of the lung interstitium. Interstitial lung diseases (ILDs) encompass a large and heterogenous group of disorders, a number of which are characterized by progressive pulmonary fibrosis that leads to respiratory failure and death. Idiopathic pulmonary fibrosis (IPF) has been described as an archetype of progressive fibrosing ILD, and the development of pirfenidone and nintedanib has been a major breakthrough in the treatment of patients with this deadly disease. Both drugs principally target scar-forming fibroblasts and have been shown to significantly slow down the accelerated decline of lung function by approximately 50%. In addition, nintedanib has been approved for patients with other progressive fibrosing ILDs and systemic sclerosis-associated ILD. However, there is still no cure for pulmonary fibrosis and no meaningful improvement of symptoms or quality of life has been shown. Advancement in research, such as the advent of single cell sequencing technology, has identified additional pathologic cell populations beyond the fibroblast which could be targeted for therapeutic purposes. The preclinical and clinical development of novel drug candidates is hampered by profound challenges such as a lack of sensitive clinical outcomes or suitable biomarkers that would provide an early indication of patient benefit. With the availability of these anti-fibrotic treatments, it has become even more difficult to demonstrate added efficacy, in particular in short-term clinical studies. Patient heterogeneity and the paucity of biomarkers of disease activity further complicate clinical development. It is conceivable that future treatment of pulmonary fibrosis will need to embrace more precision in treating the right patient at the right time, explore novel measures of efficacy, and likely combine treatment options.

Background Hospitalizations are common among patients with idiopathic pulmonary fibrosis (IPF). We investigated the impact of hospitalizations on outcomes in patients with IPF. Methods The IPF-PRO Registry is an observational US registry that enrolled patients with IPF that was diagnosed or confirmed at the enrolling center in the previous 6 months. Associations between patient characteristics and hospitalization, and between hospitalization and mortality, were analyzed using Cox regression models. Results A total of 1002 patients with IPF were enrolled into the IPF-PRO Registry. Over a median follow-up time of 23.7 months (maximum: 67.0 months), 568 patients (56.7%) had at least one hospitalization. Of these patients, 319 (56.2%) had at least one respiratory-related hospitalization and 120 (21.1%) had at least one hospitalization with ventilatory support. Younger age (HR 0.68 [95% CI 0.55, 0.84] per 5-year increase for patients Conclusions Data from the IPF-PRO Registry demonstrate that hospitalizations are common among patients with IPF. The risk of mortality during hospitalization or within 90 days of discharge was high, particularly among patients who were hospitalized for a respiratory cause or received ventilatory support. Trial registration ClinicalTrials.gov, NCT01915511. Registered 5 August 2013, https://clinicaltrials.gov/ct2/show/NCT01915511

Objective Systemic sclerosis (SSc) is associated with interstitial lung disease (ILD) and pulmonary hypertension (PH). This study was undertaken to determine the prevalence, characteristics, treatment, and outcomes of PH in a cohort of patients with SSc-associated ILD. Methods Patients with SSc-associated ILD on high-resolution computed tomography (HRCT) were included in a prospective observational cohort. Patients were screened for PH based on a standardized screening algorithm and underwent right-sided heart catheterization (RHC) if indicated. PH classification was based on hemodynamic findings and the extent of ILD on HRCT. Summary statistics and survival using the Kaplan-Meier method were calculated. Results Of the 93 patients with SSc-associated ILD included in the study, 76% were women and 65.6% had diffuse cutaneous SSc. The mean age was 54.9 years, and the mean SSc disease duration was 8 years. Twenty-nine patients (31.2%) had RHC-proven PH; of those 29 patients, 24.1% had PAH, 55.2% had World Health Organization (WHO) Group III PH, 34.5% had WHO Group III PH with pulmonary vascular resistance >3.0 Wood units, 48.3% had a PH diagnosis within 7 years of SSc onset, 82.8% received therapy for ILD, and 82.8% received therapy for PAH. The survival rate 3 years after SSc-associated ILD diagnosis for all patients was 97%. The survival rate 3 years after PH diagnosis for those with SSc-associated ILD and PH was 91%. Conclusion In a large cohort of patients with SSc-associated ILD, a significant proportion of patients had coexisting PH, which often occurs early after SSc diagnosis. Most patients were treated with ILD and PAH therapies, and survival was good. Patients with SSc-associated ILD should be evaluated for coexisting PH.

Rationale: Idiopathic pulmonary fibrosis (IPF) causes considerable global morbidity and mortality, and its mechanisms of disease progression are poorly understood. Recent observational studies have reported associations between lung dysbiosis, mortality, and altered host defense gene expression, supporting a role for lung microbiota in IPF. However, the causal significance of altered lung microbiota in disease progression is undetermined. Objectives: To examine the effect of microbiota on local alveolar inflammation and disease progression using both animal models and human subjects with IPF. Methods: For human studies, we characterized lung microbiota in BAL fluid from 68 patients with IPF. For animal modeling, we used a murine model of pulmonary fibrosis in conventional and germ-free mice. Lung bacteria were characterized using 16S rRNA gene sequencing with novel techniques optimized for low-biomass sample load. Microbiota were correlated with alveolar inflammation, measures of pulmonary fibrosis, and disease progression. Measurements and Main Results: Disruption of the lung microbiome predicts disease progression, correlates with local host inflammation, and participates in disease progression. In patients with IPF, lung bacterial burden predicts fibrosis progression, and microbiota diversity and composition correlate with increased alveolar profibrotic cytokines. In murine models of fibrosis, lung dysbiosis precedes peak lung injury and is persistent. In germ-free animals, the absence of a microbiome protects against mortality. Conclusions: Our results demonstrate that lung microbiota contribute to the progression of IPF. We provide biological plausibility for the hypothesis that lung dysbiosis promotes alveolar inflammation and aberrant repair. Manipulation of lung microbiota may represent a novel target for the treatment of IPF.

Rationale and objectives To determine the utility of routine postbronchoscopy chest radiography to detect pneumothorax. Materials and Methods This retrospective quality improvement cohort study was approved by the Institutional Review Board. All outpatients (n = 1443) who underwent protocol-driven postbronchoscopy chest radiography in one health system from January 2010 to July 2017 were identified by electronic medical record query. The prevalence of pneumothorax (with 95% confidence intervals [CI]) and clinical outcome were determined following coded review of chest radiography reports and review of the electronic medical record. The effect of smoking and lung disease on risk of pneumothorax was determined with Chi Square tests. Results Of 1443 subjects undergoing interventional bronchoscopy, 6% (93/1443) were current smokers, 35% (505/1442) were former smokers, and 35% (540/1443) had known lung disease. Pneumothorax prevalence was 3.4% (49/1443; 95% CI: 2.6%–4.5%) following any intervention and 4.1% (42/1032; 95% CI: 3.9%–5.5%) following transbronchial intervention. In those without known pre-existing pneumothorax or a confirmed false positive diagnosis, the real overall pneumothorax rate was 2.9% (42/1443; 95% CI: 2.1%–3.9%). The risk of pneumothorax did not differ based on smoking history (p = 0.99) or history of lung disease (p = 0.19). Of 49 subjects with pneumothorax, 13 were symptomatic, and 10 had a change in management including chest tube placement (N = 2), inpatient admission (N = 3), and/or observation (N = 7). No pneumothorax-related intervention was performed in asymptomatic patients. Conclusion Pneumothorax following interventional outpatient bronchoscopy is uncommon, usually asymptomatic, and often clinically insignificant. Asymptomatic postbronchoscopy patients are very low risk and may not need routine imaging.

Background Hypersensitivity pneumonitis (HP) is an interstitial lung disease with a better prognosis, on average, than idiopathic pulmonary fibrosis (IPF). We compare survival time and pulmonary function trajectory in patients with HP and IPF by radiologic phenotype. Methods HP (n = 117) was diagnosed if surgical/transbronchial lung biopsy, BAL, and exposure history results suggested this diagnosis. IPF (n = 152) was clinically and histopathologically diagnosed. All participants had a baseline high-resolution CT (HRCT) scan and FVC % predicted. Three thoracic radiologists documented radiologic features. Survival time is from HRCT scan to death or lung transplant. Cox proportional hazards models identify variables associated with survival time. Linear mixed models compare post-HRCT scan FVC % predicted trajectories. Results Subjects were grouped by clinical diagnosis and three mutually exclusive radiologic phenotypes: honeycomb present, non-honeycomb fibrosis (traction bronchiectasis and reticulation) present, and nonfibrotic. Nonfibrotic HP had the longest event-free median survival (> 14.73 years) and improving FVC % predicted (1.92%; 95% CI, 0.49-3.35; P = .009). HP with non-honeycomb fibrosis had longer survival than IPF (> 7.95 vs 5.20 years), and both groups experienced a significant decline in FVC % predicted. Subjects with HP and IPF with honeycombing had poor survival (2.76 and 2.81 years, respectively) and significant decline in FVC % predicted. Conclusions Three prognostically distinct, radiologically defined phenotypes are identified among patients with HP. The importance of pursuing a specific diagnosis (eg, HP vs IPF) among patients with non-honeycomb fibrosis is highlighted. When radiologic honeycombing is present, invasive diagnostic testing directed at determining the diagnosis may be of limited value given a uniformly poor prognosis.

The lung's unique extracellular matrix (ECM), while providing structural support for cells, is critical in the regulation of developmental organogenesis, homeostasis and injury-repair responses. The ECM, via biochemical or biomechanical cues, regulates diverse cell functions, fate and phenotype. The composition and function of lung ECM become markedly deranged in pathological tissue remodeling. ECM-based therapeutics and bioengineering approaches represent promising novel strategies for regeneration/repair of the lung and treatment of chronic lung diseases. In this review, we assess the current state of lung ECM biology, including fundamental advances in ECM composition, dynamics, topography, and biomechanics; the role of the ECM in normal and aberrant lung development, adult lung diseases and autoimmunity; and ECM in the regulation of the stem cell niche. We identify opportunities to advance the field of lung ECM biology and provide a set recommendations for research priorities to advance knowledge that would inform novel approaches to the pathogenesis, diagnosis, and treatment of chronic lung diseases.

Idiopathic pulmonary fibrosis (IPF) is a disease of progressive scarring caused by excessive extracellular matrix (ECM) deposition and activation of α-SMA-expressing myofibroblasts. Human antigen R (HuR) is an RNA binding protein that promotes protein translation. Upon translocation from the nucleus to the cytoplasm, HuR functions to stabilize messenger RNA (mRNA) to increase protein levels. However, the role of HuR in promoting ECM production, myofibroblast differentiation, and lung fibrosis is unknown. Human lung fibroblasts (HLFs) treated with transforming growth factor β1 (TGF-β1) showed a significant increase in translocation of HuR from the nucleus to the cytoplasm. TGF-β-treated HLFs that were transfected with HuR small interfering RNA had a significant reduction in α-SMA protein as well as the ECM proteins COL1A1, COL3A, and FN1. HuR was also bound to mRNA for ACTA2, COL1A1, COL3A1, and FN. HuR knockdown affected the mRNA stability of ACTA2 but not that of the ECM genes COL1A1, COL3A1, or FN. In mouse models of pulmonary fibrosis, there was higher cytoplasmic HuR in lung structural cells compared to control mice. In human IPF lungs, there was also more cytoplasmic HuR. This study is the first to show that HuR in lung fibroblasts controls their differentiation to myofibroblasts and consequent ECM production. Further research on HuR could assist in establishing the basis for the development of new target therapy for fibrotic diseases, such as IPF.

“Pulmonary function tests” reflect a number of various studies designed to evaluate the mechanics of airflow, lung volumes, and diffusing capacity of the lung. Although ordered fairly routinely, it is critical that the ordering physician understand what test is being ordered, what data they will receive back, how to interpret the data, and how to use the data to change management. Because pulmonary function studies can be physically demanding on a patient, it is important to only perform those tests that will help the clinician with prognostication or with determining changes in therapy. Pulmonary function tests are never diagnostic yet provide data to help clinicians manage their patients better. This chapter will focus on the role of pulmonary function testing in management of patients with systemic sclerosis.

Introduction: The INMARK trial investigated effects of nintedanib on blood biomarkers in subjects with IPF. Aim: To investigate the effect of nintedanib on markers of epithelial damage. Methods: Subjects (n=346) with IPF and FVC ≥80% predicted were randomised 1:2 to receive nintedanib 150 mg bid or placebo double-blind for 12 weeks, followed by open-label nintedanib for 40 weeks. Blood samples were taken at weeks 4, 8, 12, 16, 20, 24, 36, and 52. We assessed the rate of change (slope) in log10-transformed CA-125 and CA19-9 (two markers of epithelial damage) from baseline to week 12 using random coefficient regression and changes in log10-transformed CA-125 and CA19-9 over 52 weeks using a mixed model for repeated measures. Results: The adjusted rate of change in CA-125 levels from baseline to week 12 was significantly different for nintedanib vs placebo (difference -0.046 U/mL/month [95% CI ‑0.056, -0.035]; p Conclusion: CA-125 may be a biomarker of response to nintedanib in patients with IPF.

Introduction: In the INSTAGE trial in subjects with IPF and severely impaired gas exchange, nintedanib plus sildenafil had a numerically greater effect on FVC decline vs nintedanib alone, with more a pronounced effect in subjects with emphysema. Aim: Examine biomarkers of inflammation, cell damage and extracellular matrix (ECM) turnover by presence of emphysema in the INSTAGE trial. Methods: Subjects with IPF and DLco ≤35% predicted were randomised to receive nintedanib 150 mg bid plus sildenafil 20 mg tid or nintedanib 150 mg bid plus placebo. We analysed fold changes from baseline in biomarkers over 24 weeks in subjects with and without emphysema at baseline (determined based on qualitative assessment of an HRCT scan by investigators). Results: In total, 273 subjects were treated. Treatment effects were most notably different between emphysema subgroups for VICM, KL-6 and SP-D. Reductions in VICM (marker of ECM turnover) were observed with nintedanib plus sildenafil vs nintedanib alone only in subjects without emphysema. Reductions in KL-6 and SP-D (markers of epithelial injury) were observed with nintedanib plus sildenafil vs nintedanib alone only in subjects with emphysema. Conclusion: In the INSTAGE trial, nintedanib plus sildenafil reduced markers of epithelial injury vs nintedanib alone in subjects with emphysema and reduced VICM, a marker of ECM turnover, in subjects without emphysema.

Fibrosis is characterized by fibroblast activation, leading to matrix remodeling culminating in a stiff, type I collagen–rich fibrotic matrix. Alveolar epithelial cell (AEC) apoptosis is also a major feature of fibrogenesis, and AEC apoptosis is sufficient to initiate a robust lung fibrotic response. TGF-β (transforming growth factor-β) is a major driver of fibrosis and can induce both AEC apoptosis and fibroblast activation. We and others have previously shown that changes in extracellular matrix stiffness and composition can regulate the cellular response to TGF-β. In the present study, we find that type I collagen signaling promotes TGF-β–mediated fibroblast activation and inhibits TGF-β–induced AEC death. Fibroblasts cultured on type I collagen or fibrotic decellularized lung matrix had augmented activation in response to TGF-β, whereas AECs on cultured on type I collagen or fibrotic lung matrix were more resistant to TGF-β–induced apoptosis. Both of these responses were mediated by integrin α(2)β(1), a major collagen receptor. AECs treated with an α(2) integrin inhibitor or with deletion of α(2) integrin had loss of collagen-mediated protection from apoptosis. We found that mice with fibroblast-specific deletion of α(2) integrin were protected from fibrosis whereas mice with AEC-specific deletion of α(2) integrin had more lung injury and a greater fibrotic response to bleomycin. Intrapulmonary delivery of an α(2) integrin–activating collagen peptide inhibited AEC apoptosis in vitro and in vivo and attenuated the fibrotic response. These studies underscore the need for a thorough understanding of the divergent response to matrix signaling.

Introduction: The INMARK trial investigated biomarkers as predictors of disease progression in patients with IPF and preserved lung volume. Aim: To assess the association between baseline values of biomarkers of extracellular matrix turnover, inflammation and epithelial dysfunction and disease progression in the INMARK trial. Methods: Subjects with IPF and FVC ≥80% predicted were randomised 1:2 to receive nintedanib 150 mg bid or placebo for 12 weeks followed by open-label nintedanib for 40 weeks. The association between baseline levels of biomarkers and the proportion of subjects with disease progression (absolute decline in FVC ≥10% predicted or death) over 52 weeks was assessed in the placebo group using a logistic regression analysis with the baseline value of the biomarker as a linear covariate. Results: A total of 230 subjects (mean [SD] baseline FVC 98.0 [12.6]% predicted) received placebo for 12 weeks followed by open-label nintedanib for 40 weeks, of whom 70 (30.4%) had disease progression over 52 weeks. Baseline C-reactive protein degraded by MMP-1/8 (CRPM), collagen 3 degraded by MMP-9 (C3M), C-reactive protein (CRP), Krebs von den Lungen-6 (KL-6) and surfactant protein D (SP-D) were significantly associated with disease progression over 52 weeks (Table). Conclusions: Levels of CRPM, C3M, CRP, KL-6 and SP-D may be predictors of disease progression in patients with IPF and limited FVC impairment.

Idiopathic pulmonary fibrosis (IPF) is a progressive and heterogeneous interstitial lung disease of unknown origin with a low survival rate. There are few treatment options available due to the fact that mechanisms underlying disease progression are not well understood, likely because they arise from dysregulation of complex signaling networks spanning multiple tissue compartments. To better characterize these networks, we used systems-focused data-driven modeling approaches to identify cross-tissue compartment (blood and bronchoalveolar lavage) and temporal proteomic signatures that differentiated IPF progressors and non-progressors. Partial least squares discriminant analysis identified a signature of 54 baseline (week 0) blood and lung proteins that differentiated IPF progression status by the end of 80 weeks of follow-up with 100% cross-validation accuracy. Overall we observed heterogeneous protein expression patterns in progressors compared to more homogenous signatures in non-progressors, and found that non-progressors were enriched for proteomic processes involving regulation of the immune/defense response. We also identified a temporal signature of blood proteins that was significantly different at early and late progressor time points (p

Poster-Abstract

Summary The current study aimed to understand the developmental mechanisms regulating bud tip progenitor cells in the human fetal lung, which are present during branching morphogenesis, and to use this information to induce a bud tip progenitor-like population from human pluripotent stem cells (hPSCs) in vitro. We identified cues that maintained isolated human fetal lung epithelial bud tip progenitor cells in vitro and induced three-dimensional hPSC-derived organoids with bud tip-like domains. Bud tip-like domains could be isolated, expanded, and maintained as a nearly homogeneous population. Molecular and cellular comparisons revealed that hPSC-derived bud tip-like cells are highly similar to native lung bud tip progenitors. hPSC-derived epithelial bud tip-like structures survived in vitro for over 16 weeks, could be easily frozen and thawed, maintained multilineage potential, and successfully engrafted into the airways of immunocompromised mouse lungs, where they persisted for up to 6 weeks and gave rise to several lung epithelial lineages., Graphical Abstract, Highlights • Fgf7, CHIR-99021, and RA support growth of human lung bud tip progenitors in vitro • These factors induce lung bud tip progenitor-like organoids from hPSCs in vitro • hPSC-derived organoids are highly similar to human fetal bud tip progenitors • hPSC-derived bud tip organoids engraft into the injured murine airway, In this article, Jason Spence and colleagues identify a core signaling network that maintains isolated human epithelial lung bud tip progenitors in vitro and that induces a bud tip-like population from hPSCs. They show that iPSC-derived bud tip progenitors can engraft into an injured mouse airway, contribute to re-epithelialization, and differentiate into multiple lung epithelial lineages.

© 2017 by the American Thoracic Society. Rationale: Differences in the lung microbial community influence idiopathic pulmonary fibrosis (IPF) progression. Whether the lung microbiome influences IPF host defense remains unknown. Objectives: To explore the host immune response and microbial interaction in IPF as they relate to progression-free survival (PFS), fibroblast function, and leukocyte phenotypes. Methods: Paired microarray gene expression data derived from peripheral blood mononuclear cells as well as 16S ribosomal RNA sequencing data from bronchoalveolar lavage obtained as part of the COMET-IPF (Correlating Outcomes with Biochemical Markers to Estimate Time-Progression in Idiopathic Pulmonary Fibrosis) study were used to conduct association pathway analyses. The responsiveness of paired lung fibroblasts to Toll-like receptor 9 (TLR9) stimulation by CpG-oligodeoxynucleotide (CpG-ODN) was integrated into microbiome-gene expression association analyses for a subset of individuals. The relationship between associated pathways and circulating leukocyte phenotypes was explored by flow cytometry. Measurements and Main Results: Down-regulation of immune response pathways, including nucleotide-binding oligomerizationdomain (NOD)-, Toll-, and RIG1-like receptor pathways, was associated with worse PFS. Ten of the 11 PFS-associated pathways correlated with microbial diversity and individual genus, with species accumulation curve richness as a hub. Higher species accumulation curve richness was significantly associated with inhibition of NODs and TLRs, whereas increased abundance of Streptococcus correlated with increased NOD-like receptor signaling. In a network analysis, expression of up-regulated signaling pathways was strongly associated with decreased abundance of operational taxonomic unit 1341 (OTU1341; Prevotella) among individuals with fibroblasts responsive to CpG-ODN stimulation. The expression of TLR signaling pathways was also linked to CpG-ODN responsive fibroblasts, OTU1341 (Prevotella), and Shannon index of microbial diversity in a network analysis. Lymphocytes expressing C-X-C chemokine receptor 3 CD8 significantly correlated with OTU1348 (Staphylococcus). Conclusions: These findings suggest that host-microbiome interactions influence PFS and fibroblast responsiveness.

Background Surgical lung biopsy (SLB) is invasive and not possible in all patients with undiagnosed interstitial lung disease (ILD). We hypothesized that transbronchial biopsy (TBB) findings combined with clinical and high-resolution CT (HRCT) data leads to a confident diagnosis congruent to SLB and therefore avoids the need for SLB in some patients. Methods We evaluated 33 patients being investigated for suspected ILD who underwent HRCT, TBB, and SLB. First, clinicians, radiologists, and a pathologist reviewed the clinical information and HRCT and TBB findings. Clinicians were asked to provide a diagnosis and were also asked if SLB was needed for a more confident diagnosis. Subsequently, the clinical, HRCT, and SLB data were reviewed, and the same participants were asked to provide a final diagnosis. Clinician consensus and overall agreement between TBB- and SLB-based diagnoses were calculated. Results Four patients had definite usual interstitial pneumonia (UIP) on HRCT and would not be considered for biopsy using current guidelines. Of the 29 patients without a definitive HRCT diagnosis, the clinicians felt confident of the diagnosis (ie, would not recommend SLB) in six cases. In these cases, there was 100% agreement between TBB and SLB diagnoses. UIP was the most common diagnosis (n = 3) and was associated with an HRCT diagnosis of possible UIP/nonspecific interstitial pneumonia-like. Agreement was poor (33%) between TBB and SLB diagnoses when confidence in the TBB diagnosis was low. Conclusions Information from TBB, when combined with clinical and HRCT data, may provide enough information to make a confident and accurate diagnosis in approximately 20% to 30% of patients with ILD.

Summary With the recent development of two effective treatments for patients with idiopathic pulmonary fibrosis, an accurate diagnosis is crucial. The traditional approach to diagnosis emphasises the importance of thorough clinical and laboratory evaluations to exclude secondary causes of disease. High-resolution CT is a critical initial diagnostic test and acts as a tool to identify patients who should undergo surgical lung biopsy to secure a definitive histological diagnosis of usual interstitial pneumonia pattern. This diagnostic approach faces several challenges. Many patients with suspected idiopathic pulmonary fibrosis present with atypical high-resolution CT characteristics but are unfit for surgical lung biopsy, therefore preventing a confident diagnosis. The state of the art suggests an iterative, multidisciplinary process that incorporates available clinical, laboratory, imaging, and histological features. Recent research has explored genomic techniques to molecularly phenotype patients with interstitial lung disease. In the future, clinicians will probably use blood-specific or lung-specific molecular markers in combination with other clinical, physiological, and imaging features to enhance diagnostic efforts, refine prognostic recommendations, and influence the initial or subsequent treatment options. There is an urgent and increasing need for well designed, large, prospective studies measuring the effect of different diagnostic approaches. Ultimately, this will help to inform the development of guidelines and tailor clinical practice for the benefit of patients.

Idiopathic pulmonary fibrosis (IPF) is a progressive, fatal interstitial lung disease (ILD) characterized by abnormal extracellular matrix (ECM) remodeling. We hypothesized that ECM remodeling might result in a plasma profile of proteins specific for IPF that could distinguish patients with IPF from other idiopathic ILDs.To identify biomarkers that might assist in distinguishing IPF from non-IPF ILD.We developed a panel of 35 ECM, ECM-related, and lung-specific analytes measured in plasma from 86 patients with IPF (derivation cohort) and in 63 patients with IPF (validation cohort). Comparison groups included patients with rheumatoid arthritis-associated ILD (RA-ILD; n = 33), patients with alternative idiopathic ILDs (a-ILD; n = 41), and healthy control subjects (n = 127). Univariable and multivariable logistic regression models identified biomarkers that differentiated patients with IPF from those with a-ILD. Both continuous and diagnostic threshold versions of biomarkers were considered; thresholds were chosen to maximize summed diagnostic sensitivity and specificity in univariate receiver-operating characteristic curve analysis. A diagnostic score was created from the most promising analytes.Plasma surfactant protein (SP)-D 31 ng/ml, matrix metalloproteinase (MMP)-7 1.75 ng/ml, and osteopontin 6 ng/ml each significantly distinguished patients with IPF from patients with a-ILD, both individually and in a combined index. The odds ratio for IPF when at least one analyte in the index exceeded the threshold was 4.4 (95% confidence interval, 2.0-9.7; P = 0.0003). When at least two analytes were elevated, the odds ratio for IPF increased to 5.0 (95% confidence interval, 2.2-11.5; P = 0.0002).A biomarker index of SP-D, MMP-7, and osteopontin enhanced diagnostic accuracy in patients with IPF compared with those with non-IPF ILD. Our data suggest that this biomarker index may improve diagnostic confidence in IPF.

Introduction: In the INSTAGE trial in patients with IPF and severely impaired gas exchange, decline in forced vital capacity over 24 weeks was numerically lower in patients treated with nintedanib plus sildenafil vs nintedanib alone. Aim: To investigate changes in biomarkers of inflammation, lung cell damage and extracellular matrix turnover in the INSTAGE trial. Methods: Subjects with IPF and DLco ≤35% predicted were randomised to receive nintedanib 150 mg bid plus sildenafil 20 mg tid or nintedanib 150 mg bid plus placebo for 24 weeks. In pre-specified analyses, changes from baseline in biomarkers at week 24 were compared between treatment groups. Results: A total of 273 subjects were treated. Treatment with nintedanib plus sildenafil was associated with statistically significant reductions in collagen 6 degraded by MMP-2/9 (C6M) and citrullinated vimentin degraded by MMP-2/8 (VICM) vs nintedanib alone. The other biomarkers measured were also numerically reduced in patients who received combination therapy vs nintedanib alone but the differences did not reach statistical significance (Table). Conclusions: In the INSTAGE trial, biomarkers relevant to the pathophysiology of IPF were reduced in subjects treated with nintedanib plus sildenafil vs nintedanib alone for 24 weeks. These results support the potential benefits of this combination suggested by clinical endpoints.

Introduction: The INMARK trial investigated blood biomarkers as predictors of disease progression in subjects with IPF and the effect of nintedanib on changes in these biomarkers. Aim: To investigate the effect of nintedanib on changes in biomarkers of extracellular matrix turnover, inflammation and epithelial dysfunction. Methods: Subjects with IPF and FVC ≥80% predicted were randomised 1:2 to receive nintedanib 150 mg bid or placebo for 12 weeks. Absolute changes from baseline in biomarkers at weeks 4 and 12 with nintedanib vs placebo were analysed using a mixed model for repeated measures. Results: A total of 346 subjects (116 randomised to nintedanib, 230 to placebo) were treated. At baseline, mean (SD) FVC was 97.5 (13.5) % predicted. Compared with placebo, nintedanib significantly reduced levels of N-terminal propeptide of type VI collagen (Pro-C6) and surfactant protein D (SP-D), while CRP levels were significantly increased, at weeks 4 and 12 (Table). Levels of these three biomarkers were stable in the placebo group. Pro-C3 levels were significantly increased with nintedanib versus placebo at week 4 but not at week 12. Conclusions: These results suggest that nintedanib may reduce collagen synthesis, as measured by Pro-C6, and epithelial injury, as measured by SP-D, in patients with IPF and limited FVC impairment. Changes in these biomarkers were observed as early as week 4.