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Exercise-induced hypoxia is an index of the severity of interstitial lung disease. We hypothesized that desaturation during a 6-minute walk test would predict mortality for patients with usual interstitial pneumonia (n = 83) and nonspecific interstitial pneumonia (n = 22). Consecutive patients with biopsy-proven disease performed a 6-minute walk test between January 1996 and December 2001. Desaturation was defined as a fall in oxygen saturation to 88% or less during the 6-minute walk test. Desaturation was common (44 of 83 usual interstitial pneumonia and 8 of 22 nonspecific interstitial pneumonia; chi square, p = 0.39). Patients with usual interstitial pneumonia or nonspecific interstitial pneumonia who desaturated had a significantly higher mortality than patients who did not desaturate (respective log-rank tests, p = 0.0018, p = 0.0089). In patients with usual interstitial pneumonia, the presence of desaturation was associated with an increased hazard of death (hazard ratio, 4.2; 95% confidence interval, 1.40, 12.56; p = 0.01) after adjusting for age, sex, smoking, baseline diffusion capacity for carbon monoxide, FVC, and resting saturation. We conclude that knowledge of desaturation during a 6-minute walk test adds prognostic information for patients with usual interstitial pneumonia and nonspecific interstitial pneumonia.

Rationale: Primary graft dysfunction (PGD) is the main cause of early morbidity and mortality after lung transplantation. Previous studies have yielded conflicting results for PGD risk factors. Objectives: We sought to identify donor, recipient, and perioperative risk factors for PGD. Methods: We performed a 10-center prospective cohort study enrolled between March 2002 and December 2010 (the Lung Transplant Outcomes Group). The primary outcome was International Society for Heart and Lung Transplantation grade 3 PGD at 48 or 72 hours posttransplant. The association of potential risk factors with PGD was analyzed using multivariable conditional logistic regression. Measurements and Main Results: A total of 1,255 patients from 10 centers were enrolled; 211 subjects (16.8%) developed grade 3 PGD. In multivariable models, independent risk factors for PGD were any history of donor smoking (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.2-2.6; P ¼ 0.002); FI O 2 during allograft reperfusion (OR, 1.1 per 10% increase in FI O 2 ; 95% CI, 1.0-1.2; P ¼ 0.01); single lung transplant (OR, 2; 95% CI, 1.2-3.3; P ¼ 0.008); use of cardiopulmonary bypass (OR, 3.4; 95% CI, 2.2-5.3; P , 0.001); overweight (OR, 1.8; 95% CI, 1.2-2.7; P ¼ 0.01) and obese (OR, 2.3; 95% CI, 1.3-3.9; P ¼ 0.004) recipient body mass index; preoperative sarcoidosis (OR, 2.5; 95% CI, 1.1-5.6; P ¼ 0.03) or pulmonary arterial hypertension (OR, 3.5; 95% CI, 1.6-7.7; P ¼ 0.002); and mean pulmonary artery pressure (OR, 1.3 per 10 mm Hg increase; 95% CI, 1.1-1.5; P , 0.001). PGD was significantly associated with 90-day (relative risk, 4.8; absolute risk increase, 18%; P , 0.001) and 1-year (relative risk, 3; absolute risk increase, 23%; P , 0.001) mortality. Conclusions: We identified grade 3 PGD risk factors, several of which are potentially modifiable and should be prioritized for future research aimed at preventative strategies. Clinical trial registered with www.clinicaltrials.gov (NCT 00552357). What This Study Adds to the FieldWe performed a multicenter, prospective cohort study of 1,255 lung transplant recipients across 10 US transplant centers. We identified receipt of an organ from a donor with any smoking history, elevated FI O 2 during allograft reperfusion, preoperative sarcoidosis or pulmonary arterial hypertension, use of cardiopulmonary bypass, single lung transplant, large-volume blood product transfusion, elevated pulmonary arterial pressures, and overweight or obese recipient body habitus as risk factors for grade 3 PGD. Several of these risk factors are potentially modifiable, and thus may suggest preventative strategies, whereas other risk factors should be prioritized for future mechanistic research efforts.

Rationale: Primary graft dysfunction (PGD) is the main cause of early morbidity and mortality after lung transplantation. Previous studies have yielded conflicting results for PGD risk factors. Objectives: We sought to identify donor, recipient, and perioperative risk factors for PGD. Methods: We performed a 10-center prospective cohort study enrolled between March 2002 and December 2010 (the Lung Transplant Outcomes Group). The primary outcome was International Society for Heart and Lung Transplantation grade 3 PGD at 48 or 72 hours posttransplant. The association of potential risk factors with PGD was analyzed using multivariable conditional logistic regression. Measurements and Main Results: A total of 1,255 patients from 10 centers were enrolled; 211 subjects (16.8%) developed grade 3 PGD. In multivariable models, independent risk factors for PGD were any history of donor smoking (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.2-2.6; P ¼ 0.002); FI O 2 during allograft reperfusion (OR, 1.1 per 10% increase in FI O 2 ; 95% CI, 1.0-1.2; P ¼ 0.01); single lung transplant (OR, 2; 95% CI, 1.2-3.3; P ¼ 0.008); use of cardiopulmonary bypass (OR, 3.4; 95% CI, 2.2-5.3; P , 0.001); overweight (OR, 1.8; 95% CI, 1.2-2.7; P ¼ 0.01) and obese (OR, 2.3; 95% CI, 1.3-3.9; P ¼ 0.004) recipient body mass index; preoperative sarcoidosis (OR, 2.5; 95% CI, 1.1-5.6; P ¼ 0.03) or pulmonary arterial hypertension (OR, 3.5; 95% CI, 1.6-7.7; P ¼ 0.002); and mean pulmonary artery pressure (OR, 1.3 per 10 mm Hg increase; 95% CI, 1.1-1.5; P , 0.001). PGD was significantly associated with 90-day (relative risk, 4.8; absolute risk increase, 18%; P , 0.001) and 1-year (relative risk, 3; absolute risk increase, 23%; P , 0.001) mortality. Conclusions: We identified grade 3 PGD risk factors, several of which are potentially modifiable and should be prioritized for future research aimed at preventative strategies. Clinical trial registered with www.clinicaltrials.gov (NCT 00552357). What This Study Adds to the FieldWe performed a multicenter, prospective cohort study of 1,255 lung transplant recipients across 10 US transplant centers. We identified receipt of an organ from a donor with any smoking history, elevated FI O 2 during allograft reperfusion, preoperative sarcoidosis or pulmonary arterial hypertension, use of cardiopulmonary bypass, single lung transplant, large-volume blood product transfusion, elevated pulmonary arterial pressures, and overweight or obese recipient body habitus as risk factors for grade 3 PGD. Several of these risk factors are potentially modifiable, and thus may suggest preventative strategies, whereas other risk factors should be prioritized for future mechanistic research efforts.

Background The lung microbiome’s contribution to IPF pathogenesisis unknown. Using COMET-IPF (Correlating Outcomes with biochemical Markers to Estimate Time-progression in Idiopathic Pulmonary Fibrosis), the goal of this study was to determine whether unique microbial signatures would associate with disease progression. Methods IPF subjects within four years of diagnosis aged 35–80 were eligible for inclusion. Subjects were followed for up to a maximum of 80 weeks. This completed observational study is registered with ClinicalTrials.gov, number NCT01071707. Progression-free survival was defined as death, acute exacerbation, lung transplant, or decline in FVC of 10% or DLCO of 15%.DNA was isolated from 55 bronchoscopic alveolar lavage (BAL) samples. 454 pyrosequencing was used to assign operational taxonomic units (OTUs) based on a 3% sequence divergence. Adjusted Cox models identified OTUs significantly associated with progression-free survival at a p<0·10 level. These OTUs were then used in principal components (PC) analysis. The association between PCs and microbes with high factor loadings from the PC analysis and progression-free survival were examined via Cox regression analyses. Findings Mean FVC was 70·1% and mean DLCO 42·3 %predicted. Significant associations with disease progression were noted with increased % relative abundance of two OTUs identified by PC analysis, a Streptococcus OTU. (p<0·0009) and a Staphylococcus OTU(p=0·01). Strength of associations using PCs versus two OTUs alone was similar. Threshold analysis helped define a cut point for % relative abundance for each OTU associated with progression-free survival, >3·9% for the Streptococcus OTU, HR 10·19 (95% CI 2·94, 35·35; p=0·0002) and >1·8% for the Staphylococcus OTU, HR 5·06 (1·71, 14·93; p=0·003). Interpretation These preliminary data suggest IPF disease progression is associated with presence of specific members within the Staphylococcus and Streptococcus genera.

SummaryThe 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.

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BackgroundMultiple independent culture-based studies have identified the presence of Pseudomonas aeruginosa in respiratory samples as a positive risk factor for bronchiolitis obliterans syndrome (BOS). Yet, culture-independent microbiological techniques have identified a negative association between Pseudomonas species and BOS. Our objective was to investigate whether there may be a unifying explanation for these apparently dichotomous results.MethodsWe performed bronchoscopies with bronchoalveolar lavage (BAL) on lung transplant recipients (46 procedures in 33 patients) and 26 non-transplant control subjects. We analyzed bacterial communities in the BAL fluid using qPCR and pyrosequencing of 16S rRNA gene amplicons and compared the culture-independent data with the clinical metadata and culture results from these subjects.FindingsRoute of bronchoscopy (via nose or via mouth) was not associated with changes in BAL microbiota (p = 0.90). Among the subjects with positive Pseudomonas bacterial culture, P. aeruginosa was also identified by culture-independent methods. In contrast, a distinct Pseudomonas species, P. fluorescens, was often identified in asymptomatic transplant subjects by pyrosequencing but not detected via standard bacterial culture. The subject populations harboring these two distinct pseudomonads differed significantly with respect to associated symptoms, BAL neutrophilia, bacterial DNA burden and microbial diversity. Despite notable differences in culturability, a global database search of UM Hospital Clinical Microbiology Laboratory records indicated that P. fluorescens is commonly isolated from respiratory specimens.InterpretationWe have reported for the first time that two prominent and distinct Pseudomonas species (P. fluorescens and P. aeruginosa) exist within the post-transplant lung microbiome, each with unique genomic and microbiologic features and widely divergent clinical associations, including presence during acute infection.