Bronchoalveolar Lavage Markers Research Articles

Key inflammatory markers in bronchoalveolar lavage predict bronchiectasis progression in young children with CF

IntroductionInflammation appears early in cystic fibrosis (CF) pathogenesis, with specific elevated inflammatory markers in bronchoalveolar lavage fluid (BALF) correlating with structural lung disease.Our aim was to identify markers of airway inflammation able to predict bronchiectasis progression over two years with high sensitivity and specificity. MethodsChildren with CF with two chest computed tomography (CT) scans and bronchoscopies at a two-year interval were included (n= 10 at 1 and 3 years and n= 27 at 3 and 5 years). Chest CTs were scored for increase in bronchiectasis (Δ%Bx), using the PRAGMA-CF score. BALF collected with the first CT scan were analyzed for neutrophil% (n= 36), myeloperoxidase (MPO) (n= 25), neutrophil elastase (NE) (n= 26), and with a protein array for inflammatory and fibrotic markers (n= 26). ResultsMPO, neutrophil%, and inducible T-cell costimulator ligand (ICOSLG), but not clinical characteristics, correlated significantly with Δ%Bx. Evaluation of neutrophil%, NE, MPO, interleukin-8 (IL-8), ICOSLG, and hepatocyte growth factor (HGF), for predicting an increase of > 0.5% of Δ%Bx in two years, showed that IL-8 had the best sensitivity (82%) and specificity (73%). Neutrophil%, ICOSLG and HGF had sensitivities of 85, 82, and 82% and specificities of 59, 67 and 60%, respectively. The odds ratio for risk of >0.5% Δ%Bx was higher for IL-8 (12.4) than for neutrophil%, ICOSLG, and HGF (5.9, 5.3, and 6.7, respectively). Sensitivity and specificity were lower for NE and MPO). ConclusionsHigh levels of IL-8, neutrophil%, ICOSGL and HGF in BALF may be good predictors for progression of bronchiectasis in young children with CF.

Genetic Deletion of Mmp9 Does Not Reduce Airway Inflammation and Structural Lung Damage in Mice with Cystic Fibrosis-like Lung Disease.

Elevated levels of matrix metalloprotease 9 (MMP-9) and neutrophil elastase (NE) are associated with bronchiectasis and lung function decline in patients with cystic fibrosis (CF). MMP-9 is a potent extracellular matrix-degrading enzyme which is activated by NE and has been implicated in structural lung damage in CF. However, the role of MMP-9 in the in vivo pathogenesis of CF lung disease is not well understood. Therefore, we used β-epithelial Na+ channel-overexpressing transgenic (βENaC-Tg) mice as a model of CF-like lung disease and determined the effect of genetic deletion of Mmp9 (Mmp9-/-) on key aspects of the pulmonary phenotype. We found that MMP-9 levels were elevated in the lungs of βENaC-Tg mice compared with wild-type littermates. Deletion of Mmp9 had no effect on spontaneous mortality, inflammatory markers in bronchoalveolar lavage, goblet cell metaplasia, mucus hypersecretion and emphysema-like structural lung damage, while it partially reduced mucus obstruction in βENaC-Tg mice. Further, lack of Mmp9 had no effect on increased inspiratory capacity and increased lung compliance in βENaC-Tg mice, whereas both lung function parameters were improved with genetic deletion of NE. We conclude that MMP-9 does not play a major role in the in vivo pathogenesis of CF-like lung disease in mice.

Activation of angiotensin II type‐2 receptor protects against cigarette smoke‐induced COPD

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death globally. Cumulative evidence has implicated renin-angiotensin system (RAS) in the pathogenesis of COPD. This study aimed to investigate potential protective effects of angiotensin II type-2 receptor (AT2R) activation in cigarette smoke (CS)-induced COPD models and alveolar macrophages. Compound 21 (C21), a selective and potent non-peptide small molecule AT2R agonist, was evaluated for anti-inflammatory, anti-oxidative and anti-remodeling activities in a two-week (acute) and an eight-week (chronic) CS-induced COPD models. C21 inhibited CS-induced increases in macrophage and neutrophil counts, pro-inflammatory cytokines and oxidative damage markers in bronchoalveolar lavage (BAL) fluid, and TGF-β1 in lung tissues, from COPD models. C21 restored phosphatase activities and reduced phospho-p38 MAPK, phospho-ERK and p65 subunit of NF-κB levels in CS-exposed lung tissues. C21 also suppressed CS-induced increases in α-Sma, Mmp9, Mmp12and hydroxyproline levels in lung tissues, and neutrophil elastase activity in BAL fluid. C21 modulated RAS in CS-exposed lungs by downregulating Ang II but upregulating Ang-(1-7) and Mas receptor levels. C21 prevented CS-induced emphysema and improved lung functions in chronic COPD model. In conclusion, AT2R agonist C21 facilitates protective effects against CS-induced COPD, and provide strong evidence for further exploration of AT2R agonist effects on CS-induced alveolar macrophages.

Bronchoalveolar Lavage Markers of Inflammation Early Post Lung-Transplant are Associated with CLAD and Death

Bronchoalveolar Lavage Markers of Inflammation Early Post Lung-Transplant are Associated with CLAD and Death

The role of eosinophils in sepsis and acute respiratory distress syndrome: a scoping review.

PurposeSeptic shock and acute respiratory distress syndrome (ARDS) are characterized by a dysregulated immune host response that may respond to steroid therapy. Eosinophils contribute to type 2 inflammation that often responds to steroid therapy; their role in immune dysregulation and outcomes in sepsis and ARDS is unclear.SourceA systematic search of Cochrane Library, MEDLINE, and EMBASE was performed from inception to 9 September 2020. The search comprised the following terms: eosinophils, sepsis, septic shock, and ARDS. Two reviewers independently screened abstracts and texts and extracted data on disease severity and clinical outcomes.Principal findingsThirty-nine studies were identified: 30 evaluated serum eosinophil count in sepsis, one evaluated eosinophil activity in sepsis, three assessed bronchoalveolar lavage (BAL) eosinophil count in ARDS, four assessed eosinophil activity in ARDS, and one assessed peripheral eosinophil count in ARDS. Eleven studies showed an association between eosinopenia and sepsis, and eight studies found persistent eosinopenia at > 48 hr of intensive care unit admission to predict mortality and readmission in septic patients. Three studies found BAL eosinophil count to be low in ARDS, although one found that levels rose in late-phase ARDS. Three studies found eosinophil activity markers in BAL to be high in ARDS and correlate with ARDS severity.ConclusionPersistent peripheral eosinopenia is a marker of bacterial sepsis and is independently associated with poor outcomes. Bronchoalveolar lavage eosinophil counts are low in early-phase ARDS, but increase in late-phase ARDS, while elevated markers of eosinophil activity correlate with ARDS severity. Further studies understanding the mechanisms leading to eosinopenia in sepsis and increased eosinophil activity in ARDS are needed.Supplementary InformationThe online version of this article (10.1007/s12630-021-01920-8) contains supplementary material, which is available to authorized users.

Activation of angiotensin II type-2 receptor protects against cigarette smoke-induced COPD

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death globally. Cumulative evidence has implicated renin-angiotensin system (RAS) in the pathogenesis of COPD. This study aimed to investigate potential protective effects of angiotensin II type-2 receptor (AT2R) activation in cigarette smoke (CS)-induced COPD models. Compound 21 (C21), a selective and potent non-peptide small molecule AT2R agonist, was evaluated for anti-inflammatory, anti-oxidative and anti-remodeling activities in a two-week (acute) and an eight-week (chronic) CS-induced COPD models. C21 inhibited CS-induced increases in macrophage and neutrophil counts, pro-inflammatory cytokines and oxidative damage markers in bronchoalveolar lavage (BAL) fluid, and TGF-β1 in lung tissues, from COPD models. C21 restored phosphatase activities and reduced phospho-p38 MAPK, phospho-ERK and p65 subunit of NF-κB levels in CS-exposed lung tissues. C21 also suppressed CS-induced increases in α-Sma, Mmp9, Mmp12 and hydroxyproline levels in lung tissues, and neutrophil elastase activity in BAL fluid. C21 modulated RAS in CS-exposed lungs by downregulating Ang II but upregulating Ang-(1–7) and Mas receptor levels. C21 prevented CS-induced emphysema and improved lung functions in chronic COPD model. We report here for the first time the protective effects of AT2R agonist C21 against CS-induced COPD, and provide strong evidence for further development of AT2R agonist for the treatment of COPD.

WS04.1 Inflammatory markers in BronchoAlveolar Lavage as risk factors for early cystic fibrosis Lung disease: the I-BALL study

WS04.1 Inflammatory markers in BronchoAlveolar Lavage as risk factors for early cystic fibrosis Lung disease: the I-BALL study

Bronchoalveolar Lavage Markers of Inflammation Early Post Lung-Transplant are Associated with CLAD and Death

Surveillance bronchoscopies with bronchoalveolar lavage (BAL) and transbronchial biopsies (TBB) are used in the evaluation of patients after lung transplant to detect acute cellular rejection (ACR) or infection. We have previously shown that a focused BAL protein signature early post-transplant may predict CLAD or death in a subset of clinically-stable patients with A1 ACR. The aim of the current study was to determine whether similar BAL markers would have similar predictive characteristics irrespective of ACR grade. The cohort consisted of all adult, first, bilateral lung transplants performed 2010-2017. Clinical status was categorized as unstable or stable based on presence or absence of ≥10% concurrent drop in FEV1. Clinically-stable patients with grade AX TBB (which are not routinely treated at our center, thus avoiding the confounding effect of ACR treatment) during the first-year post-transplant, not preceded by ACR (grade A≥1 or grade B≥1) were included. IL6, S100A8, IL10, TNF-receptor1, IL-1α, pentraxin3 and CXCL10, previously shown to be associated with worse outcomes, were measured in the BAL using a multiplex bead assay. Association with subsequent CLAD or death was assessed using Cox proportional hazards models adjusted for age, sex, native lung disease, and CMV-mismatch. 107 patients matched the inclusion criteria with a stable AX occurring at a median time of 188 days (IQR 96-279) post-transplant. Median time from AX TBB to CLAD or death was 462 (IQR 330, 928) and 582 days (IQR 251-1410), respectively. In multivariable models, levels of CXCL10 and IL10 were associated with both CLAD development and death while IL6, S100A8 and pentraxin3 were only associated with death (P<0.05 for all). A focused BAL protein signature in clinically-stable patients with ungradable TBB, early post-transplant, may be informative in determining a subset of patients who are at increased risk for worse outcome and may benefit from a more aggressive management strategy.

Diagnosis of Fungal Infections. A Systematic Review and Meta-Analysis Supporting American Thoracic Society Practice Guideline

Rationale: Prompt diagnosis of invasive fungal infections is important because of the associated morbidity and mortality; however, diagnosis is challenging because of the nonspecific symptoms and radiographic findings.Objectives: To conduct a systematic review and meta-analysis of studies that evaluated the diagnostic accuracy of serum and bronchoalveolar lavage (BAL) galactomannan (GM) and serum or BAL polymerase chain reaction (PCR) in patients with suspected invasive aspergillosis (IA), β-d-glucan in critically ill patients at risk for candidiasis or candidemia, and serology testing and antigen detection in patients with endemic mycoses (histoplasmosis, blastomycosis, and coccidioidomycosis).Methods: Studies were selected and appraised by pairs of reviewers. Bivariate random effects meta-analysis was used to generate pooled sensitivity, specificity, and diagnostic likelihood ratios.Results: Serum GM in patients with impaired immunity suspected of having IA had sensitivity of 0.71 (95% confidence interval [CI], 0.64-0.78) and specificity of 0.89 (95% CI, 0.84-0.92). A cutoff of 1 optical density index yielded optimal sensitivity and specificity. BAL GM in patients with impaired immunity suspected of having IA had sensitivity of 0.84 (95% CI, 0.73-0.91) and specificity of 0.88 (95% CI, 0.81-0.91). Serum or whole-blood PCR in immunocompromised patients with suspected IA had sensitivity of 0.81 (95% CI, 0.73-0.86) and specificity of 0.79 (95% CI, 0.68-0.86). BAL PCR in patients at high risk for IA had high sensitivity of 0.90 (95% CI, 0.77-0.96) and specificity of 0.96 (95% CI, 0.93-0.98) for diagnosing IA. β-d-glucan assay in patients in the intensive care unit at risk for invasive candidiasis or candidemia had sensitivity of 0.81 (95% CI, 0.74-0.86) and specificity of 0.60 (95% CI, 0.49-0.71). Data on diagnostic accuracy of antigen detection and serology testing for endemic mycoses were limited and heterogeneous (varied according to test, patient immunity, and suspected endemic disease).Conclusions: The diagnosis of invasive fungal infections remains a challenge. Various serum and BAL markers can aid in diagnosis. This evidence supports the development of clinical practice recommendations by the American Thoracic Society.

Epithelial cell death markers in bronchoalveolar lavage correlate with chronic lung allograft dysfunction subtypes and survival in lung transplant recipients-a single-center retrospective cohort study.

Chronic lung allograft dysfunction (CLAD) remains the leading cause of late death after lung transplantation. Epithelial injury is thought to be a key event in the pathogenesis of CLAD. M30 and M65 are fragments of cytokeratin-18 released specifically during epithelial cell apoptosis and total cell death, respectively. We investigated whether M30 and M65 levels in bronchoalveolar lavage (BAL) correlate with CLAD subtypes: restrictive allograft syndrome (RAS) versus bronchiolitis obliterans syndrome (BOS). BALs were obtained from 26 patients with established CLAD (10 RAS, 16 BOS) and 19 long-term CLAD-free controls. Samples with concurrent infection or acute rejection were excluded. Protein levels were measured by ELISA. Variables were compared using Kruskal-Wallis, Mann-Whitney U test and Chi-squared tests. Association of M30 and M65 levels with post-CLAD survival was assessed using a Cox PH models. M65 levels were significantly higher in RAS compared to BOS and long-term CLAD-free controls and correlated with worse post-CLAD survival. Lung epithelial cell death is enhanced in patients with RAS. Detection of BAL M65 may be used to differentiate CLAD subtypes and as a prognostic marker in patients with established CLAD. Understanding the role of epithelial cell death in CLAD pathogenesis may help identify new therapeutic targets to improve outcome.

Bronchoalveolar Lavage Cytokine Profiles Reflect Involvement in Pulmonary Recovery After Pulmonary Hypertension in a Pig Model of Endotoxin‐Induced Acute Lung Injury

We previously demonstrated in a pig model of acute lung injury (ALI) with endotoxin (ETX)‐induced pulmonary hypertension (PHN) that different cytokines in the circulation appear to mediate pulmonary vasoactivity vs alveolar gas exchange. Despite improvements in PHN and blood gas exchange, serum cytokine levels remain elevated several hours after ETX exposure. With prolonged elevated levels of cytokines, it would be logical that some would be involved in pulmonary recovery from ETX.We sought to further explore the relationship between cytokines and ALI by evaluating lung cytokine levels after ETX‐induced ALI. We tested the hypothesis that cytokine profiles in bronchoalveolar lavage (BAL) specimens several hours after ETX exposure would reflect a reparative response and be different from the blood cytokine profile seen at the initiation of inflammation.Anesthetized Yorkshire cross piglets (n = 17, 7.5 ± 0.2 kg body weight) were catheterized and baseline hemodynamics and blood gases were assessed. E. coli ETX was administered (up to 35,000 units i.v.) and titrated to achieve ALI criteria of PaO2/FiO2 less than 350 mmHg. Pulmonary to systemic vascular resistance ratios (PVR/SVR) were elevated in pigs receiving ETX (0.49 ± 0.04, n = 12) compared to controls (0.20 ± 0.01, n = 5). Blood was obtained every 2–4 hours for blood gases and cytokine profiles (Milliplex MAP for Luminex, MagPix). After 16 hours, BAL was performed for cytokine profiles. Hemodynamic measurements and cytokine levels remained constant in the control group.Compared to controls, blood TNF‐alpha levels remain elevated for 6–10 hours after ETX exposure (p &lt;0.05), while other cytokine levels returned to baseline levels within 2–6 hours. In contrast, BAL obtained 12–16 hours after ETX exposure, showed IL‐2 (0.97 ± 0.11 vs 0.58 ± 0.11 pg/ml, p&lt;0.057), IL‐4 (1.17 ± 0.13 vs 0.59 ± 0.05 pg/ml, p&lt;0.015), and IL‐8 (418 ± 62 vs 167 ± 40 pg/ml, p&lt;0.026) to remain elevated in ETX versus control pigs, respectively.Multiple regression analysis was performed to determine which BAL markers may be related to changes in pulmonary vasoconstriction versus gas exchange. BAL obtained 12–16 hours after ALI compared against PVR/SVR levels during the ALI period showed that PVR/SVR was negatively related to BAL IL‐1b and positively related to BAL IL‐8 and IL‐1a (r = 0.91, p&lt;0.0013). PaO2/FiO2 during early ALI was negatively related to IL‐8 and IL‐6, and positively correlated with IL‐1b, IL‐12, and TNF‐alpha (r = 0.940, p&lt;0.0001) in BAL specimens. The association of elevated BAL IL‐8 with more severe PHN and hypoxemia is consistent with IL‐8 functioning as a chemotactic factor to cause cell migration to inflamed regions of the lung. The prolonged elevation of BAL cytokines specific to regulation of tissue regeneration may serve as good markers for assessment of lung injury severity long after blood circulating cytokine levels have normalized.Support or Funding InformationThis project was funded by the US Army Medical Command. The views expressed in this abstract are those of the authors and do not reflect the official policy or position of the Department of the Army, Department of Defense, or the U.S. Government.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Subacute inhalation toxicity study of synthetic amorphous silica nanoparticles in Sprague-Dawley rats

Synthetic amorphous silica nanoparticles (SiNPs) are one of the most applied nanomaterials and are widely used in a broad variety of industrial and biomedical fields. However, no recent long-term inhalation studies evaluating the toxicity of SiNPs are available and results of acute studies are limited. Thus, we conducted a subacute inhalation toxicity study of SiNPs in Sprague-Dawley rats using a nose-only inhalation system. Rats were separated into four groups and target concentrations selected in this study were as follows: control (fresh air), low- (0.407 ± 0.066 mg/m3), middle- (1.439 ± 0.177 mg/m3) and high-concentration group (5.386 ± 0.729 mg/m3), respectively. The rats were exposed to SiNPs for four consecutive weeks (6 hr/day, 5 days/week) except for control group of rats which received filtered fresh air. After 28-days of inhalation exposure to SiNPs, rats were sacrificed after recovery periods of one, seven and 28 days. Although there were minimal toxic changes such as temporary decrease of body weight after exposure, increased levels of red blood cells (RBCs) and hemoglobin (Hb) concentration, the lung histopathological findings and inflammatory markers in bronchoalveolar lavage (BAL) fluid including polymorphonuclear (PMN) leukocyte, lactate dehydrogenase (LDH), albumin and protein did not show significant changes at any recovery period. The results of this study suggest that the subacute inhalation of SiNPs had no toxic effects on the lung of rats at the concentrations and selected time points used in this study.

Persistent effects of Libby amphibole and amosite asbestos following subchronic inhalation in rats.

BackgroundHuman exposure to Libby amphibole (LA) asbestos increases risk of lung cancer, mesothelioma, and non-malignant respiratory disease. This study evaluated potency and time-course effects of LA and positive control amosite (AM) asbestos fibers in male F344 rats following nose-only inhalation exposure.MethodsRats were exposed to air, LA (0.5, 3.5, or 25.0 mg/m3 targets), or AM (3.5 mg/m3 target) for 10 days and assessed for markers of lung inflammation, injury, and cell proliferation. Short-term results guided concentration levels for a stop-exposure study in which rats were exposed to air, LA (1.0, 3.3, or 10.0 mg/m3), or AM (3.3 mg/m3) 6 h/day, 5 days/week for 13 weeks, and assessed 1 day, 1, 3, and 18 months post-exposure. Fibers were relatively short; for 10 mg/m3 LA, mean length of all structures was 3.7 μm and 1 % were longer than 20 μm.ResultsTen days exposure to 25.0 mg/m3 LA resulted in significantly increased lung inflammation, fibrosis, bronchiolar epithelial cell proliferation and hyperplasia, and inflammatory cytokine gene expression compared to air. Exposure to 3.5 mg/m3 LA resulted in modestly higher markers of acute lung injury and inflammation compared to AM. Following 13 weeks exposure, lung fiber burdens correlated with exposure mass concentrations, declining gradually over 18 months. LA (3.3 and 10.0 mg/m3) and AM produced significantly higher bronchoalveolar lavage markers of inflammation and lung tissue cytokines, Akt, and MAPK/ERK pathway components compared to air control from 1 day to 3 months post-exposure. Histopathology showed alveolar inflammation and interstitial fibrosis in all fiber-exposed groups up to 18 months post-exposure. Positive dose trends for incidence of alveolar epithelial hyperplasia and bronchiolar/alveolar adenoma or carcinoma were observed among LA groups.ConclusionsInhalation of relatively short LA fibers produced inflammatory, fibrogenic, and tumorigenic effects in rats which replicate essential attributes of asbestos-related disease in exposed humans. Fiber burden, inflammation, and activation of growth factor pathways may persist and contribute to lung tumorigenesis long after initial LA exposure. Fiber burden data are being used to develop a dosimetry model for LA fibers, which may provide insights on mode of action for hazard assessment.Electronic supplementary materialThe online version of this article (doi:10.1186/s12989-016-0130-z) contains supplementary material, which is available to authorized users.

Airway, but not serum or urinary, levels of YKL-40 reflect inflammation in early cystic fibrosis lung disease

BackgroundCystic fibrosis (CF) lung disease begins in early life and is progressive with the major risk factor being an exaggerated inflammatory response. Currently, assessment of neutrophilic inflammation in early cystic fibrosis (CF) lung disease relies on bronchoalveolar lavage (BAL). The chitinase-like protein YKL-40 is raised in sputum and serum of adults with CF. We investigated YKL-40 in BAL, serum and urine to determine whether this reflected inflammation and infection in young children with CF.MethodsYKL-40 was measured in matched samples of BAL, serum and urine obtained from 36 infants and young children with CF participating in an early surveillance program. Levels were compared to clinical data and markers of inflammation detected in the lung.ResultsYKL-40 in BAL correlated with pulmonary infection [β=1.30 (SE 0.34), p < 0.001] and BAL markers of inflammation [macrophage number: r2 = 0.34, p < 0.001; neutrophil number: r2 = 0.74, p < 0.001; neutrophil elastase: r2 = 0.47, p < 0.001; CXCL8: r2 = 0.45, p < 0.001; IL-β: r2 = 0.62, p < 0.001]. YKL-40 was detectable in serum but levels did not correlate with BAL levels in the same individuals (r2 = 0.04, p = 0.14) or with inflammatory markers. YKL-40 was below the limit of detection in urine (30 pg/ml).ConclusionsThis study demonstrates that levels of the chitinase-like protein YKL-40 reflect airway inflammation and infection in early CF lung disease. The lack of increased YKL-40 in serum in the absence of systemic inflammation limits the benefit of this potential biomarker in early disease.

S94 Tumour Necrosis Factor receptor 1 inhibition using a novel inhaled human antibody reduces inflammation in a human model of lung injury induced by inhaled lipopolysaccharide; a randomised placebo-controlled clinical trial

Introduction and ObjectivesTumour Necrosis Factor receptor 1 (TNFR1) transduces the pro-inflammatory activity of TNF-α, whereas signalling through TNFR2 may contribute to tissue repair. Attenuation of TNFR1 signalling, whilst simultaneously preserving...

Metformin Attenuates the Exacerbation of the Allergic Eosinophilic Inflammation in High Fat-Diet-Induced Obesity in Mice

A positive relationship between obesity and asthma has been well documented. The AMP-activated protein kinase (AMPK) activator metformin reverses obesity-associated insulin resistance (IR) and inhibits different types of inflammatory responses. This study aimed to evaluate the effects of metformin on the exacerbation of allergic eosinophilic inflammation in obese mice. Male C57BL6/J mice were fed for 10 weeks with high-fat diet (HFD) to induce obesity. The cell infiltration and inflammatory markers in bronchoalveolar lavage (BAL) fluid and lung tissue were evaluated at 48 h after ovalbumin (OVA) challenge. HFD obese mice displayed peripheral IR that was fully reversed by metformin (300 mg/kg/day, two weeks). OVA-challenge resulted in higher influx of total cell and eosinophils in lung tissue of obese mice compared with lean group. As opposed, the cell number in BAL fluid of obese mice was reduced compared with lean group. Metformin significantly reduced the tissue eosinophil infiltration and prevented the reduction of cell counts in BAL fluid. In obese mice, greater levels of eotaxin, TNF-α and NOx, together with increased iNOS protein expression were observed, all of which were normalized by metformin. In addition, metformin nearly abrogated the binding of NF-κB subunit p65 to the iNOS promoter gene in lung tissue of obese mice. Lower levels of phosphorylated AMPK and its downstream target acetyl CoA carboxylase (ACC) were found in lung tissue of obese mice, which were restored by metformin. In separate experiments, the selective iNOS inhibitor aminoguanidine (20 mg/kg, 3 weeks) and the anti-TNF-α mAb (2 mg/kg) significantly attenuated the aggravation of eosinophilic inflammation in obese mice. In conclusion, metformin inhibits the TNF-α-induced inflammatory signaling and NF-κB-mediated iNOS expression in lung tissue of obese mice. Metformin may be a good pharmacological strategy to control the asthma exacerbation in obese individuals.

Repeatability of and Relationship between Potential COPD Biomarkers in Bronchoalveolar Lavage, Bronchial Biopsies, Serum, and Induced Sputum

Chronic Obstructive Pulmonary Disease (COPD) is a chronic inflammatory disease, primarily affecting the airways. Stable biomarkers characterizing the inflammatory phenotype of the disease, relevant for disease activity and suited to predict disease progression are needed to monitor the efficacy and safety of drug interventions. We therefore analyzed a large panel of markers in bronchoalveolar lavage, bronchial biopsies, serum and induced sputum of 23 healthy smokers and 24 smoking COPD patients (GOLD II) matched for age and gender. Sample collection was performed twice within a period of 6 weeks. Assays for over 100 different markers were validated for the respective matrices prior to analysis. In our study, we found 51 markers with a sufficient repeatability (intraclass correlation coefficient >0.6), most of these in serum. Differences between groups were observed for markers from all compartments, which extends (von-Willebrand-factor) and confirms (e.g. C-reactive-protein, interleukin-6) previous findings. No correlations between lung and serum markers were observed, including A1AT. Airway inflammation defined by sputum neutrophils showed only a moderate repeatability. This could be improved, when a combination of neutrophils and four sputum fluid phase markers was used to define the inflammatory phenotype.In summary, our study provides comprehensive information on the repeatability and interrelationship of pulmonary and systemic COPD-related markers. These results are relevant for ongoing large clinical trials and future COPD research. While serum markers can discriminate between smokers with and without COPD, they do not seem to sufficiently reflect the disease-associated inflammatory processes within the airways.

Atherogenic and pulmonary responses of ApoE- and LDL receptor-deficient mice to sidestream cigarette smoke

Plasma lipoproteins play important roles in the development and progression of atherosclerosis. Two widely used mouse models of experimental atherosclerosis, apolipoprotein E-deficient (ApoE −/−) and LDL receptor-deficient (LDLr −/−) mice, have major differences in lipoprotein characteristics. These include differences in lipoprotein cholesterol distribution, lipoprotein compositions, apoliporoteins distribution, and susceptibility to oxidation. In the present study, we compared pulmonary and cardiovascular responses of ApoE −/− and LDLr −/− mice to sidestream cigarette smoke (SSCS) exposure to determine if strain differences influence their predisposition to SSCS-mediated promotion of atherosclerosis. Female ApoE −/− and LDLr −/− mice were maintained on a saturated fat enriched diet and exposed to SSCS in whole body exposure chambers for 15 weeks (4h/day, 5 days/week). At terminations, the levels of pulmonary injury markers in bronchoalveolar lavage (BAL) fluids from 6 mice per group and atherosclerotic lesion formation in 14 mice per group were analyzed. Total BAL cells and polymorphonuclear leukocytes were not significantly altered by SSCS exposure in both mouse models. Total protein, LDH, and cytokine concentrations in cell-free BAL fluids were also not significantly affected by chronic SSCS exposure in either mouse strain. SSCS significantly reduced surfactant protein D levels in both strains to a similar extent. However, SSCS exposure increased significantly the percent atherosclerotic lesion areas covering aortic intimal surfaces of ApoE −/− (control-25.3±1.52 vs. SSCS-31.9±2.02, p=0.012) as well as in LDLr −/− (control-30.97±1.1 vs. SSCS-36.61±1.7, p=0.028) mice. In contrast, the serum cholesterol concentrations of SSCS-exposed ApoE −/− mice were similar to that of controls (control-1255±85 vs. SSCS-1190±61mg/dl, p=0.552) but increased significantly in SSCS-exposed LDLr −/− mice (control-998±114 vs. SSCS-1577±142mg/dl, p=0.008). These results showing different effects of identical SSCS exposure on plasma cholesterol concentrations in these two mouse models suggest a role of multiple mechanisms in SSCS-induced atherosclerosis.

Atrial natriuretic peptide protects against Staphylococcus aureus-induced lung injury and endothelial barrier dysfunction

Lung inflammation and alterations in endothelial cell (EC) permeability are key events to development of acute lung injury (ALI). Protective effects of atrial natriuretic peptide (ANP) have been shown against inflammatory signaling and endothelial barrier dysfunction induced by gram-negative bacterial wall liposaccharide. We hypothesized that ANP may possess more general protective effects and attenuate lung inflammation and EC barrier dysfunction by suppressing inflammatory cascades and barrier-disruptive mechanisms shared by gram-negative and gram-positive pathogens. C57BL/6J wild-type or ANP knockout mice (Nppa-/-) were treated with gram-positive bacterial cell wall compounds, Staphylococcus aureus-derived peptidoglycan (PepG) and/or lipoteichoic acid (LTA) (intratracheal, 2.5 mg/kg each), with or without ANP (intravenous, 2 μg/kg). In vitro, human pulmonary EC barrier properties were assessed by morphological analysis of gap formation and measurements of transendothelial electrical resistance. LTA and PepG markedly increased pulmonary EC permeability and activated p38 and ERK1/2 MAP kinases, NF-κB, and Rho/Rho kinase signaling. EC barrier dysfunction was further elevated upon combined LTA and PepG treatment, but abolished by ANP pretreatment. In vivo, LTA and PepG-induced accumulation of protein and cells in the bronchoalveolar lavage fluid, tissue neutrophil infiltration, and increased Evans blue extravasation in the lungs was significantly attenuated by intravenous injection of ANP. Accumulation of bronchoalveolar lavage markers of LTA/PepG-induced lung inflammation and barrier dysfunction was further augmented in ANP-/- mice and attenuated by exogenous ANP injection. These results strongly suggest a protective role of ANP in the in vitro and in vivo models of ALI associated with gram-positive infection. Thus ANP may have important implications in therapeutic strategies aimed at the treatment of sepsis and ALI-induced gram-positive bacterial pathogens.

Elevated mRNA levels of CTLA-4, FoxP3, and Granzyme B in BAL, but not in blood, during acute rejection of lung allografts

Introduction Regulatory T cells (Tregs) have been related to acute rejection as have the cytotoxic T cells, their immunological counterpart. High expression of cytotoxic markers has been related to acute rejection incidents following both kidney and intestine transplantation, while the correlation between FoxP3 expression and acute rejection is still being debated. Some studies have been performed on blood samples from lung-transplanted patients, while others have investigated the local immune response in the lungs by analysing broncho-alveolar-lavage (BAL) fluids or biopsies. Biopsies are considered the gold standard in diagnosis of acute rejection. Aim The aim was to measure the expression of both Treg (FoxP3, CD25 and CTLA-4) and cytotoxic (granzyme B, granulysin, and perforin) markers in BAL and blood samples from lung-transplanted patients to investigate the possible relation of expression and acute rejection incidents in order to develop a non-invasive diagnostic method for acute rejection. Materials and methods 24 lung-transplanted patients were included in this 6-month cross-section study. BAL and blood samples were analysed for FoxP3, CD25, CTLA-4, granzyme B, granulysin, perforin, CD4 and CD8 mRNA by QRT-PCR with glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as primary reference. Results We demonstrate that the mRNA levels in BAL relative to GAPDH of nearly all markers are elevated during acute rejection; CTLA-4, FoxP3, and granzyme B significantly, while a strong tendency is seen among the others. No significant differences were detected in blood. Conclusion CTLA-4, FoxP3 and Granzyme B mRNA levels are elevated during acute rejection in BAL, but not in blood, following lung transplantation, indicating that evaluation of Treg and cytotoxic marker expression in BAL can be used in the assessment of allograft rejection state.