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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.

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.

© 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.

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.

Ineffective repair of a damaged alveolar epithelium has been postulated to cause pulmonary fibrosis. In support of this theory, epithelial cell abnormalities, including hyperplasia, apoptosis, and persistent denudation of the alveolar basement membrane, are found in the lungs of humans with idiopathic pulmonary fibrosis and in animal models of fibrotic lung disease. Furthermore, mutations in genes that affect regenerative capacity or that cause injury/apoptosis of type II alveolar epithelial cells have been identified in familial forms of pulmonary fibrosis. Although these findings are compelling, there are no studies that demonstrate a direct role for the alveolar epithelium or, more specifically, type II cells in the scarring process.To determine if a targeted injury to type II cells would result in pulmonary fibrosis.A transgenic mouse was generated to express the human diphtheria toxin receptor on type II alveolar epithelial cells. Diphtheria toxin was administered to these animals to specifically target the type II epithelium for injury. Lung fibrosis was assessed by histology and hydroxyproline measurement.Transgenic mice treated with diphtheria toxin developed an approximately twofold increase in their lung hydroxyproline content on Days 21 and 28 after diphtheria toxin treatment. The fibrosis developed in conjunction with type II cell injury. Histological evaluation revealed diffuse collagen deposition with patchy areas of more confluent scarring and associated alveolar contraction.The development of lung fibrosis in the setting of type II cell injury in our model provides evidence for a causal link between the epithelial defects seen in idiopathic pulmonary fibrosis and the corresponding areas of scarring.

Rationale: Tissue fibrosis is considered a dysregulated wound-healing response. Fibronectin containing extra type III domain A (EDA) is implicated in the regulation of wound healing. EDA-containing fibronectin is deposited during wound repair, and its presence precedes that of collagen. Objectives: To investigate the role of EDA-containing fibronectin in lung fibrogenesis. Methods: Primary lung fibroblasts from patients with idiopathic pulmonary fibrosis or from patients undergoing resection for lung cancer were assessed for EDA-containing fibronectin and α-smooth muscle actin (α-SMA) expression. Mice lacking the EDA domain of fibronectin and their wild-type littermates were challenged with the bleomycin model of lung fibrosis. Primary lung fibroblasts from these mice were assayed in vitro to determine the contribution of EDA-containing fibronectin to fibroblast phenotypes. Measurements and Main Results: Idiopathic pulmonary fibrosis lung fibroblasts produced markedly more EDA-containing fibronectin and α-SMA than control fibroblasts. EDA-null mice failed to develop significant fibrosis 21 days after bleomycin challenge, whereas wild-type controls developed the expected increase in total lung collagen. Histologic analysis of EDA-null lungs after bleomycin showed less collagen and fewer α-SMA–expressing myofibroblasts compared with that observed in wild-type mice. Failure to develop lung fibrosis in EDA-null mice correlated with diminished activation of latent transforming growth factor (TGF)-β and decreased lung fibroblast responsiveness to active TGF-β in vitro. Conclusions: The data show that EDA-containing fibronectin is essential for the fibrotic resolution of lung injury through TGF-β activation and responsiveness, and suggest that EDA-containing fibronectin plays a critical role in tissue fibrogenesis.

Rationale: Asymptomatic relatives of patients with familial interstitial pneumonia (FIP), the inherited form of idiopathic interstitial pneumonia, carry increased risk for developing interstitial lung disease. Objectives: Studying these at-risk individuals provides a unique opportunity to investigate early stages of FIP pathogenesis and develop predictive models of disease onset. Methods: Seventy-five asymptomatic first-degree relatives of FIP patients (mean age, 50.8 yr) underwent blood sampling and high-resolution chest computed tomography (HRCT) scanning in an ongoing cohort study; 72 consented to bronchoscopy with bronchoalveolar lavage (BAL) and transbronchial biopsies. Twenty-seven healthy individuals were used as control subjects. Measurements and Main Results: Eleven of 75 at-risk subjects (14%) had evidence of interstitial changes by HRCT, whereas 35.2% had abnormalities on transbronchial biopsies. No differences were noted in inflammatory cells in BAL between at-risk individuals and control subjects. At-risk subjects had increased herpesvirus DNA in cell-free BAL and evidence of herpesvirus antigen expression in alveolar epithelial cells (AECs), which correlated with expression of endoplasmic reticulum stress markers in AECs. Peripheral blood mononuclear cell and AEC telomere length were shorter in at-risk individuals than healthy control subjects. The minor allele frequency of the Muc5B rs35705950 promoter polymorphism was increased in at-risk subjects. Levels of several plasma biomarkers differed between at-risk subjects and control subjects, and correlated with abnormal HRCT scans. Conclusions: Evidence of lung parenchymal remodeling and epithelial dysfunction was identified in asymptomatic individuals at risk for FIP. Together, these findings offer new insights into the early pathogenesis of idiopathic interstitial pneumonia and provide an ongoing opportunity to characterize presymptomatic abnormalities that predict progression to clinical disease.

A 57-year-old man underwent high-resolution computed tomography (HRCT) scanning and bronchoscopy as part of an evaluation for dyspnea and exercise intolerance. Physical examination was without abnormalities. Incidental note was made of an air-filled structure (black arrow) medial to the bronchus intermedius (BI) on HRCT (Figure 1). Bronchoscopy revealed normal airways, except for an accessory (cardiac) bronchus (ACB) arising from the BI (Figure 2). Figure 1. Figure 2. ACB occur in up to 0.5% of the general population and usually end as a blind pouch. They may also be associated with small amounts of pulmonary parenchyma. ACB are almost always an incidental finding, although they may be a reservoir of infectious material, source of hemoptysis, or origin of malignancy. The most common location of ACB is the inferomedial wall of the right mainstem bronchus, but can be found arising from the BI as seen in this patient.