Differential inflammatory response to inhaled lipopolysaccharide targeted either to the airways or the alveoli in man

Targeting transitioning lung monocytes/macrophages as treatment strategies in lung disease related to environmental exposures

BACKGROUND

Environmental/occupational exposures cause significant lung diseases. Agricultural organic dust extracts (ODE) and bacterial component lipopolysaccharide (LPS) induce recruited, transitioning murine lung monocytes/macrophages, yet their cellular role remains unclear.

METHODS

CCR2 RFP+ mice were intratracheally instilled with high concentration ODE (25%), LPS (10 μg), or gram-positive peptidoglycan (PGN, 100 μg) for monocyte/macrophage cell-trafficking studies. CCR2 knockout (KO) mice and administration of intravenous clodronate liposomes strategies were employed to reduce circulating monocytes available for lung recruitment following LPS exposure. Lung tissues and bronchoalveolar lavage fluid (BALF) were collected. Pro-inflammatory and/or pro-fibrotic cytokines, chemokines, and lung extracellular matrix mediators were quantitated by ELISA. Infiltrating lung cells including monocyte/macrophage subpopulations, neutrophils, and lymphocytes were characterized by flow cytometry. Lung histopathology, collagen content, vimentin, and post-translational protein citrullination and malondialdehyde acetaldehyde (MAA) modification were quantitated. Parametric statistical tests (one-way ANOVA, Tukey'smultiple comparison) and nonparametric statistical (Kruskal-Wallis, Dunn's multiple comparison) tests were used following Shapiro-Wilk testing for normality.

RESULTS

Intratracheal instillation of ODE, LPS, or PGN robustly induced the recruitment of inflammatory CCR2+ CD11cintCD11bhi monocytes/macrophages and both CCR2+ and CCR2- CD11c-CD11bhi monocytes at 48 h. There were also increases in CCR2+ CD4+ and CD8+ T cells and NK cells. Despite reductions in LPS-induced lung infiltrating CD11cintCD11bhi cells (54% reduction), CCR2 knockout (KO) mice were not protected against LPS-induced inflammatory and pro-fibrotic consequences. Instead, compensatory increases in lung neutrophils and CCL2 and CCL7 release occurred. In contrast, the depletion of circulating monocytes through the administration of intravenous clodronate (vs. vehicle) liposomes 24 h prior to LPS exposure reduced LPS-induced infiltrating CD11cintCD11bhi monocyte-macrophage subpopulation by 59% without compensatory changes in other cell populations. Clodronate liposome pre-treatment significantly reduced LPS-induced IL-6 (66% reduction), matrix metalloproteinases (MMP)-3 (36%), MMP-8 (57%), tissue inhibitor of metalloproteinases (61%), fibronectin (38%), collagen content (22%), and vimentin (40%). LPS-induced lung protein citrullination and MAA modification, post-translational modifications implicated in lung disease, were reduced (39% and 48%) with clodronate vs. vehicle liposome.

CONCLUSION

Highly concentrated environmental/occupational exposures induced the recruitment of CCR2+ and CCR2- transitioning monocyte-macrophage and monocyte subpopulations and targeting peripheral monocytes may reduce the adverse lung consequences resulting from exposures to LPS-enriched inhalants.

Characterization of the lung microbiome and inflammatory cytokine levels in women exposed to environmental risk factors: A pilot study

INTRODUCTION

Lung microbiome dysbiosis affects the immune system balance and promotes lung inflammation. We aimed to characterize and compare the lung bacteriome composition and the cytokine profile in women with normal lung function exposed to risk factors for chronic lung diseases (tobacco smoking and biomass-burning smoke exposure).

METHODS

We included women with biomass-burning smoke exposure (BE, n = 11) and current smokers women (TS, n = 10). The bacteriome composition was performed in induced sputum, sequencing the 16 rRNA gene. Cytokine levels were measured using enzyme-linked immunosorbent assay multiplex assay in the supernatant of induced sputum. For quantitative variables, we used medians and minimum and maxim values. For the amplicon sequence variants (ASV) differential abundance testing between groups.

RESULTS

At the taxa level, the phylum Proteobacteria was found in a higher proportion in the TS group concerning BE (p = .045); however, after the false discovery rate adjustment, this difference was not retained (p = .288). We found a higher concentration of IL-1β in the TS group than in the BE group (248.6 vs. 177.9 pg/mL, p = .010). Women with high biomass-burning smoke exposure in an hour per day had a positive correlation with the abundance of Bacteroidota (ρ = 0.71, p = .014) and Fusobacteriota (ρ = 0.73, p = .011). FEV1/FVC had a positive correlation with an abundance of Bacteroidota, Proteobacteria, and Fusobacteria (ρ = 0.74, p = .009, ρ = 0.85, p = .001, and ρ = 0.83, p = .001, respectively). In tobacco smoking, women had a positive correlation (ρ = 0.77, p = .009) between cigarettes per day and Firmicutes' abundance.

CONCLUSION

Compared to biomass-burning smoke-exposed women, current smokers have poor lung function and high levels of IL-1β in sputum. Women with biomass-burning smoke exposure present an increased abundance of Bacteroidota and Fusobacteriota.

Association of exacerbation phenotype with the sputum microbiome in chronic obstructive pulmonary disease patients during the clinically stable state

Background

Chronic obstructive pulmonary disease (COPD) is a progressive, life-threatening lung disease with increasing prevalence and incidence worldwide. Increasing evidence suggests that lung microbiomes might play a physiological role in acute exacerbations of COPD. The objective of this study was to characterize the association of the microbiota and exacerbation risk or airflow limitation in stable COPD patients.

Methods

The sputum microbiota from 78 COPD outpatients during periods of clinical stability was investigated using 16S rRNA V3-V4 amplicon sequencing. The microbiome profiles were compared between patients with different risks of exacerbation, i.e., the low risk exacerbator (LRE) or high risk exacerbator (HRE) groups, and with different airflow limitation severity, i.e., mild to moderate (FEV1 ≥ 50; PFT I) or severe to very severe (FEV1 < 50; PFT II).

Results

The bacterial diversity (Chao1 and observed OTUs) was significantly decreased in the HRE group compared to that in the LRE group. The top 3 dominant phyla in sputum were Firmicutes, Actinobacteria, and Proteobacteria, which were similar in the HRE and LRE groups. At the genus level, compared to that in the LRE group (41.24%), the proportion of Streptococcus was slightly decreased in the HRE group (28.68%) (p = 0.007). However, the bacterial diversity and the proportion of dominant bacteria at the phylum and genus levels were similar between the PFT I and PFT II groups. Furthermore, the relative abundances of Gemella morbillorum, Prevotella histicola, and Streptococcus gordonii were decreased in the HRE group compared to those in the LRE group according to linear discriminant analysis effect size (LEfSe). Microbiome network analysis suggested altered bacterial cooperative regulation in different exacerbation phenotypes. The proportions of Proteobacteria and Neisseria were negatively correlated with the FEV1/FVC value. According to functional prediction of sputum bacterial communities through Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) analysis, genes involved in lipopolysaccharide biosynthesis and energy metabolism were enriched in the HRE group.

Conclusion

The present study revealed that the sputum microbiome changed in COPD patients with different risks of exacerbation. Additionally, the bacterial cooperative networks were altered in the HRE patients and may contribute to disease exacerbation. Our results provide evidence that sputum microbiome community dysbiosis is associated with different COPD phenotypes, and we hope that by understanding the lung microbiome, a potentially modifiable clinical factor, further targets for improved COPD therapies during the clinically stable state may be elucidated.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-02788-4.

Noninvasive Monitoring of the Response of Human Lungs to Low-Dose Lipopolysaccharide Inhalation Challenge Using MRI: A Feasibility Study

BACKGROUND

Development of antiinflammatory drugs for lung diseases demands novel methods for noninvasive assessment of inflammatory processes in the lung.

PURPOSE

To investigate the feasibility of hyperpolarized ¹²⁹ Xe MRI, ¹ H T₁ time mapping, and dynamic contrast-enhanced (DCE) perfusion MRI for monitoring the response of human lungs to low-dose inhaled lipopolysaccharide (LPS) challenge compared to inflammatory cell counts from induced-sputum analysis.

STUDY TYPE

Prospective feasibility study.

POPULATION

Ten healthy volunteers underwent MRI before and 6 hours after inhaled LPS challenge with subsequent induced-sputum collection.

FIELD STRENGTH/SEQUENCES

1.5T/hyperpolarized ¹²⁹ Xe MRI: Interleaved multiecho imaging of dissolved and gas phase, ventilation imaging, dissolved-phase spectroscopy, and chemical shift saturation recovery spectroscopy. ¹ H MRI: Inversion recovery fast low-angle shot imaging for T₁ mapping, time-resolved angiography with stochastic trajectories for DCE MRI.

ASSESSMENT

Dissolved-phase ratios of ¹²⁹ Xe in red blood cells (RBC), tissue/plasma (TP) and gas phase (GP), ventilation defect percentage, septal wall thickness, surface-to-volume ratio, capillary transit time, lineshape parameters in dissolved-phase spectroscopy, ¹ H T₁ time, blood volume, flow, and mean transit time were determined and compared to cell counts.

STATISTICAL TESTS

Wilcoxon signed-rank test, Pearson correlation.

RESULTS

The percentage of neutrophils in sputum was markedly increased after LPS inhalation compared to baseline, P = 0.002. The group median RBC-TP ratio was significantly reduced from 0.40 to 0.31, P = 0.004, and ¹ H T₁ was significantly elevated from 1157.6 msec to 1187.8 msec after LPS challenge, P = 0.027. DCE MRI exhibited no significant changes in blood volume, P = 0.64, flow, P = 0.17, and mean transit time, P = 0.11.

DATA CONCLUSION

Hyperpolarized ¹²⁹ Xe dissolved-phase MRI and ¹ H T₁ mapping may provide biomarkers for noninvasive assessment of the response of human lungs to LPS inhalation. By its specificity to the alveolar region, hyperpolarized ¹²⁹ Xe MRI together with ¹ H T₁ mapping adds value to sputum analysis.

LEVEL OF EVIDENCE

1 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:1669-1676.

Endotoxin and particulate matter emitted by livestock farms and respiratory health effects in neighboring residents

BACKGROUND

Living in livestock-dense areas has been associated with health effects, suggesting airborne exposures to livestock farm emissions to be relevant for public health. Livestock farm emissions involve complex mixtures of various gases and particles. Endotoxin, a pro-inflammatory agent of microbial origin, is a constituent of livestock farm emitted particulate matter (PM) that is potentially related to the observed health effects. Quantification of livestock associated endotoxin exposure at residential addresses in relation to health outcomes has not been performed earlier.

OBJECTIVES

We aimed to assess exposure-response relations for a range of respiratory endpoints and atopic sensitization in relation to livestock farm associated PM₁₀ and endotoxin levels.

METHODS

Self-reported respiratory symptoms of 12,117 persons participating in a population-based cross-sectional study were analyzed. For 2494 persons, data on lung function (spirometry) and serologically assessed atopic sensitization was additionally available. Annual-average PM₁₀ and endotoxin concentrations at home addresses were predicted by dispersion modelling and land-use regression (LUR) modelling. Exposure-response relations were analyzed with generalized additive models.

RESULTS

Health outcomes were generally more strongly associated with exposure to livestock farm emitted endotoxin compared to PM₁₀. An inverse association was observed for dispersion modelled exposure with atopic sensitization (endotoxin: p = .004, PM₁₀: p = .07) and asthma (endotoxin: p = .029, PM₁₀: p = .022). Prevalence of respiratory symptoms decreased with increasing endotoxin concentration at the lower range, while at the higher range prevalence increased with increasing concentration (p < .05). Associations between lung function parameters with exposure to PM₁₀ and endotoxin were not statistically significant (p > .05).

CONCLUSIONS

Exposure to livestock farm emitted particulate matter is associated with respiratory health effects and atopic sensitization in non-farming residents. Results indicate endotoxin to be a potentially plausible etiologic agent, suggesting non-infectious aspects of microbial emissions from livestock farms to be important with respect to public health.

Pulmonary neutrophilia caused by absence of the NF-κB member RelB is dampened by exposure to cigarette smoke

Inflammation is a response to injury and infection. Although protective under physiological conditions, excessive and persistent inflammation is linked to numerous diseases. As the lungs are continuously exposed to the external environment, the respiratory system is particularly liable to damage from inflammation. RelB is a member of the non-canonical NF-κB pathway that may control lung inflammation caused by cigarette smoke (CS), a leading cause of morbidity and mortality worldwide. Our lab has previously shown that RelB protects against CS-induced inflammation in vitro, leading us to hypothesize that RelB would protect against acute CS-induced pulmonary inflammation in vivo. We exposed wild-type (Relb+/+) and RelB-deficient mice (Relb-/-) mice to room air or to CS and found that CS exposure caused a sustained decrease in pulmonary granulocytes in Relb-/- mice that was predominated by a decrease in neutrophils. Pulmonary inflammation caused by other irritants, including chlorine, ovalbumin (OVA; to mimic features of asthma) and lipopolysaccharide (LPS) was not controlled by RelB. Differential cytokine analysis suggests that alterations in chemotactic cytokines do not fully account for the CS-specific decrease in neutrophils in Relb-/- mice. Flow cytometric analysis of the bronchoalveolar lavage and bone marrow cells also reveal that it is unlikely that the sustained decrease is caused by excessive cell death or decreased hematopoiesis from the bone marrow. Overall, our results indicate that RelB regulates acute CS-induced pulmonary inflammation. Understanding how RelB regulates CS-induced inflammation may potentiate the discovery of new therapeutic strategies for many of the inflammatory diseases caused by CS.

Effects of ozonation on the activity of endotoxin and its inhalation toxicity in reclaimed water

Aerosolized reclaimed water can cause inflammatory responses in lung after inhalation, and endotoxin has been identified as the main inducer. Since the effects of disinfection treatments on endotoxins had conflicting results, this study explored the changes of endotoxin activity and inflammation inducing ability of reference endotoxin, gram-negative bacteria solutions and reclaimed water after ozonation respectively, and found that LAL assay based endotoxin activity and mouse inhalation exposure based inflammation examination had inconsistent results. The excessive ozone could not remove the endotoxin activity, but was able to reduce the inflammation inducing ability of free endotoxin. When treating on gram-negative strains, ozone first released the cell-bound endotoxin and caused the dramatic increase of endotoxin activity. But for the inflammatory response, despite the rapid increase at the very beginning, it immediately dropped back with further ozonation. The endotoxin aggregate size was proposed as a key regulator of the toxicity of endotoxin, which was modified by ozone oxidation. In real reclaimed water, insufficient ozone significantly enhanced the inflammatory response, but when the ozone dosages were large enough, the inflammation could be drawn back to the original level, which was consistent with the observations from pure endotoxin and bacteria. This work demonstrates that the endotoxin activity cannot predict the endotoxin-induced toxicity of ozone treated water, and low dosage of ozone treatment may even increase the health risk of reclaimed water.

Anti-inflammatory activities and potential mechanisms of phenolic acids isolated from Salvia miltiorrhiza f. alba roots in THP-1 macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

The roots of Salvia miltiorrhiza f. alba (Lamiaceae) (RSMA) are used as the Danshen, a traditional Chinese medicine, to treat the vascular diseases at local clinics, especially for the remedy of thromboangiitis obliterans (TAO) more than 100 years. Phenolic acids are one of the major effective constituents of RSMA, and some studies have linked phenolic acids with anti-inflammatory functions.

AIM OF THE STUDY

The purpose of this research was to isolate phenolic acids from RSMA and investigate their anti-inflammatory effects and potential mechanisms.

MATERIALS AND METHODS

Nine already known compounds were obtained from RSMA. Their structures were elucidated through the spectroscopic analysis and comparing the reported data. The anti-inflammatory effects and potential mechanisms were investigated in LPS-stimulated THP-1 cells, using salvianolic acid B (SalB) as the positive control. The enzyme-linked immunosorbent assays (ELISA) were used to determine the secretory protein levels of interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). And quantitative real-time polymerase chain reaction (qRT-PCR) was used to analyze the mRNA levels of these inflammatory cytokines. The expression of TLR4, p65, p-p65, IκBα, and p-IκBα were measured using western blot.

RESULTS

All these compounds, except for rosmarinic acid (5) and isosalvianolic acid (6) for IL-6 protein levels, rosmarinic acid-o-β-D-glucopyranoside (3) for IL-6 mRNA, and rosmarinic acid-o-β-D-glucopyranoside (3), rosmarinic acid (5) and isosalvianolic acid (6) for TNF-α mRNA levels, remarkably inhibited the production of TNF-α, IL-1β, and IL-6 at the concentration of 5 and 25 μM in the mRNA and protein levels. Lithospermic acid (7) showed the strongest inhibitory effect among them and was similar to that of SalB. In particular, lithospermic acid (7) and SalB markedly downregulated the expressions of TLR4, p-p65, and p-IκBα induced by LPS in THP-1 macrophages.

CONCLUSIONS

All the phenolic acids displayed anti-inflammatory properties and the potential mechanisms involved the TLR4/NF-κB signal pathway. Results of this study indicate that phenolic acids may be effective constituents of RSMA to treat vascular diseases associated with inflammation.

Pre-natal and post-natal exposure to pet ownership and lung function in children: The Seven Northeastern Cities Study

To evaluate the association between pre-natal and post-natal exposure to pet ownership and lung function in children, a cross-sectional study named Seven Northeastern Cities (SNEC) study was conducted. In this study, children's lung function including the forced expiratory volume in 1 second (FEV₁ ), forced vital capacity (FVC), maximal mid-expiratory flow (MMEF), and peak expiratory flow (PEF) were measured by spirometers, and pet ownership situations were collected by questionnaire. Analyzed by multiple logistic regression and generalized linear modeling, we found that for all subjects, pet exposure in the first 2 years of life was significantly associated with lung function impairment of FVC<85% predicted (adjusted odds ratio [aOR]=1.28; 95% confidence interval [CI]: 1.01, 1.63). For current pet exposure, the increased odds of lung function impairment ranged from 35% (aOR=1.35; 95%CI: 1.12, 1.62) for FVC<85% predicted to 57% (aOR=1.57; 95%CI: 1.29, 1.93) for FEV₁ <85% predicted. The in utero exposure was not related to lung function impairment. Compared with other pets, higher odds were observed among children with dogs. When stratified by gender, girls with current pet exposure were more likely to have lung function impairment than boys. It implies self-reported exposures to pets were negatively associated with lung function among the children under study.

AT-RvD1 modulates the activation of bronchial epithelial cells induced by lipopolysaccharide and Dermatophagoides pteronyssinus

Bronchial epithelial cells are essential to airways homeostasis; however, they are also involved in exacerbation of airway inflammatory responses of patients with conditions such as asthma. Dermatophagoides pteronyssinus (Dp), the most important allergen, and lipopolysaccharide (LPS), both of which are present in house dust mites (HDM), can activate immune and structural cells (such as bronchial epithelial cells) and modulate the airway inflammation in asthma patients. Resolvin D1 (RvD1) and its epimer aspirin-triggered-resolvin D1 (AT-RvD1) are lipid mediators that are produced during the resolution of inflammation and demonstrate anti-inflammatory and pro-resolution effects in several experimental models including experimental models of allergic airway inflammation. Here, we evaluated the effects of AT-RvD1 (10^-12-10^-10 M) on human bronchial epithelial cells (BEAS-2B) stimulated with LPS (2μg/ml) or Dp (10μg/ml). After 24h, the C-C motif chemokine ligand 2 (CCL-2) production was increased in cells that had been stimulated with LPS and Dp compared to the control. However, AT-RvD1 (10^-11 and 10^-10 M) significantly reduced the concentration of CCL-2 in a manner that was dependent on the N-formyl peptide receptor 2 (FPR2/ALX) and nuclear factor kappa B (NF-κB) pathways in cells stimulated with LPS or Dp compared to controls. In addition, AT-RvD1 reduced the phosphorylation of signal transducer and activator of transcription (STAT)6 and STAT1 in cells stimulated with Dp and LPS, respectively. In conclusion, AT-RvD1 demonstrated significant anti-inflammatory effects in bronchial epithelial cells that were stimulated with LPS or Dp, which provides new perspectives for therapeutic strategies to control inflammatory airway diseases.

Holi colours contain PM10 and can induce pro-inflammatory responses

Background

At Holi festivals, originally celebrated in India but more recently all over the world, people throw coloured powder (Holi powder, Holi colour, Gulal powder) at each other. Adverse health effects, i.e. skin and ocular irritations as well as respiratory problems may be the consequences. The aim of this study was to uncover some of the underlying mechanisms.

Methods

We analysed four different Holi colours regarding particle size using an Electric field cell counting system. In addition, we incubated native human cells with different Holi colours and determined their potential to induce a pro-inflammatory response by quantifying the resulting cytokine production by means of ELISA (Enzyme Linked Immunosorbent Assay) and the resulting leukocyte oxidative burst by flow cytometric analysis. Moreover, we performed the XTT (2,3-Bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) and Propidium iodide cytotoxicity tests and we measured the endotoxin content of the Holi colour samples by means of the Limulus Amebocyte Lysate test (LAL test).

Results

We show here that all tested Holi colours consist to more than 40 % of particles with an aerodynamic diameter smaller than 10 μm, so called PM10 particles (PM, particulate matter). Two of the analysed Holi powders contained even more than 75 % of PM10 particles.

Furthermore we demonstrate in cell culture experiments that Holi colours can induce the production of the pro-inflammatory cytokines TNF-α (Tumor necrosis factor-α), IL-6 (Interleukine-6) and IL-1β (Interleukine-1β). Three out of the four analysed colours induced a significantly higher cytokine response in human PBMCs (Peripheral Blood Mononuclear Cells) and whole blood than corn starch, which is often used as carrier substance for Holi colours. Moreover we show that corn starch and two Holi colours contain endotoxin and that certain Holi colours display concentration dependent cytotoxic effects in higher concentration. Furthermore we reveal that in principle Holi colours and corn starch are able to generate an oxidative burst in human granulocytes and monocytes. In Holi colour 1 we detected a fungal contamination.

Conclusions

Some of the observed unwanted health effects of Holi colours might be explained by the high content of PM10 particles in conjunction with the possible induction of a pro-inflammatory response and an oxidative leukocyte burst.

Inflammation induced by inhaled lipopolysaccharide depends on particle size in healthy volunteers

AIMS

In drug development, the anti-inflammatory properties of new molecules in the lung are currently tested using the inhaled lipopolysaccharide (LPS) model. The total and regional lung bioavailability of inhaled particles depends significantly on their size. The objective of the present study was to compare inflammatory responses in healthy volunteers after the inhalation of LPS of varying droplet size.

METHODS

Three nebulizers were characterized by different droplet size distributions [mean mass median aerodynamic diameters: Microcirrus (2.0 μm), MB2 (3.2 μm) and Pari (7.9 μm)]. Participants inhaled three boluses of a 20 μg (technetium 99 m-labelled) solution of LPS, randomly delivered by each nebulizer. We measured the lung deposition of the nebulized LPS by gamma-scintigraphy, while blood and sputum biomarkers were evaluated before and after challenges.

RESULTS

MB2 and Pari achieved greater lung deposition than Microcirrus [171.5 (±72.9) and 217.6 (±97.8) counts pixel^-1 , respectively, vs. 67.9 (±20.6) counts pixel^-1 ; P < 0.01]. MB2 and Pari caused higher levels of blood C-reactive protein and more total cells and neutrophils in sputum compared with Microcirrus (P < 0.05). C-reactive protein levels correlated positively with lung deposition (P < 0.01).

CONCLUSIONS

Inhalation of large droplets of LPS gave rise to greater lung deposition and induced a more pronounced systemic and bronchial inflammatory response than small droplets. The systemic inflammatory response correlated with lung deposition. NCT01081392.

Prediction of survival of diffuse large B-cell lymphoma patients via the expression of three inflammatory genes

Currently, several gene-expression signatures that were used to predict survival of diffuse large B-cell lymphoma (DLBCL) patients, showed a restriction on the practical work for lack of convenient operation. In this study, we screened inflammatory genes whose expression correlated with survival of DLBCL and established a predictive model including IL6, IL1A and CSF3 through multivariate Cox regression based on the expression of these three genes. We validated the model at protein level in our clinical serum cohort composed of 101 patients of DLBCL and 50 healthy controls and 534 DLBCL patients at mRNA level from three independent Gene Expression Omnibus (GEO) data sets. We found our model to be independent of the International Prognostic Index (IPI), moreover, it can augment the predictive power of IPI. In summary, our three-gene model is sufficient to predict survival of DLBCL patients via measuring the concentration of three inflammatory cytokines in peripheral blood.

Dissociation between systemic and pulmonary anti-inflammatory effects of dexamethasone in humans

Aims

The local pulmonary inflammatory response has a different temporal and qualitative profile compared with the systemic inflammatory response. Although glucocorticoids substantially downregulate the systemic release of acute‐phase mediators, it is not clear whether they have comparable inhibitory effects in the human lung compartment. Therefore, we compared the anti‐inflammatory effects of a pure glucocorticoid agonist, dexamethasone, on bronchoalveolar lavage and blood cytokine concentrations in response to bronchially instilled endotoxin.

Methods

In this randomized, double‐blind and placebo‐controlled trial, 24 volunteers received dexamethasone or placebo and had endotoxin instilled into a lung segment and saline instilled into a contralateral segment, followed by bronchoalveolar lavage.

Results

Bronchially instilled endotoxin induced a local and systemic inflammatory response. Dexamethasone strongly blunted the systemic interleukin (IL) 6 and C‐reactive protein release. In sharp contrast, dexamethasone left the local release of acute‐phase mediators in the lungs virtually unchanged: bronchoalveolar lavage levels of IL‐6 were only 18% lower and levels of IL‐8 were even higher with dexamethasone compared with placebo, although the differences between treatments were not statistically significant (P = 0.07 and P = 0.08, respectively). However, dexamethasone had inhibitory effects on pulmonary protein extravasation and neutrophil migration.

Conclusions

The present study demonstrated a remarkable dissociation between the systemic anti‐inflammatory effects of glucocorticoids and its protective effects on capillary leak on the one hand and surprisingly low anti‐inflammatory effects in the lungs on the other.

Effect of inhaled endotoxin on mucociliary clearance and airway inflammation in mild smokers and nonsmokers

BACKGROUND

In healthy nonsmokers, inhaled endotoxin [lipopolysaccharide (LPS)] challenge induces airway neutrophilia and modifies innate immune responses, but the effect on mucociliary clearance (MCC), a key host defense response, is unknown. Although smokers are chronically exposed to LPS through inhaled tobacco smoke, the acute effect of inhaled LPS on both MCC and airway inflammation is also unknown. The purpose of this study was to determine the effect of inhaled LPS on MCC in nonsmokers and mild smokers with normal pulmonary function.

METHODS

We performed an open-label inhalational challenge with 20,000 endotoxin units in healthy adult nonsmokers (n=18) and young adult, mild smokers (n=12). At 4 hr post LPS challenge, we measured MCC over a period of 2 hr, followed by sputum induction to assess markers of airway inflammation.

RESULTS

No significant changes in spirometry occurred in either group following LPS challenge. Following LPS, MCC was significantly (p<0.05) slowed in nonsmokers, but not in smokers [MCC=10±9% (challenge) vs. 15±8% (baseline), MCC=14±9% (challenge) vs. 16±10% (baseline), respectively]. Both groups showed a significant (p<0.05) increase in sputum neutrophils 6 hr post LPS challenge versus baseline. Although there was no correlation between the increased neutrophilia and depressed MCC post LPS in the nonsmokers, baseline neutrophil concentration predicted the LPS-induced decrease in MCC in the nonsmokers, i.e., lower baseline neutrophil concentration was associated with greater depression in MCC with LPS challenge (p<0.05).

CONCLUSIONS

These data show that a mild exposure to endotoxin acutely slows MCC in healthy nonsmokers. MCC in mild smokers is unaffected by mild endotoxin challenge, likely due to preexisting effects of cigarette smoke on their airway epithelium.

Soluble CD44 and vascular endothelial growth factor levels in patients with acute primary angle closure

PURPOSE

Acute elevation of intraocular pressure (IOP) in acute primary angle closure (APAC) can cause huge damage to the variable cells in the eye; however, the mechanisms that connect the two processes still remain unclear. In this study, we aim to evaluate the levels of soluble CD44 (sCD44) and vascular endothelial growth factor (VEGF) in the aqueous humour of acute primary angle closure patients.

METHODS

This study included 24 eyes of 24 APAC patients (11 eyes with current APAC and 13 eyes with previous APAC) and 15 eyes of 15 cataract subjects. Clinical data were acquired, and aqueous humour was collected. The levels of sCD44 and VEGF in the aqueous humour were determined by ELISA and magnetic bead immunoassay technique.

RESULTS

The concentrations of the sCD44 and VEGF in the current APAC were 9.9 ± 8.8 ng/ml and 2440.2 ± 2107.1 ng/ml, respectively, which were significantly higher when compared to the previous APAC group (p = 0.001) and cataract (p < 0.001); however, there were no significant differences between the group with previous APAC and with cataract. Higher IOP was associated with higher concentration of sCD44 (Rho = 0.617, p = 0.001). The concentration of the VEGF in aqueous humour of APAC patients was closely related to the sCD44 levels (Rho = 0.752, p < 0.001).

CONCLUSION

After acute increase of IOP in the APAC, the level of sCD44 and VEGF increased significantly in the aqueous humour. The damage due to high IOP may therefore be mediated through the release of sCD44.

Elevated exhaled leukotriene B₄ in the small airway compartment in children with asthma

BACKGROUND

Inflammatory processes in the asthmatic lung involve the large and small airway and alveolar sites. Leukotriene B4 (LTB₄) is an important disease marker, but its role in inflammation of the small airways in asthma has not been established yet.

OBJECTIVE

To distinguish between large and small airway or alveolar LTB₄ concentrations in children with asthma using the new technique of fractionated exhaled breath condensate sampling.

METHODS

Sixty-eight children (9-17 years old, 33 children with asthma and 35 controls) underwent fractional exhaled nitric oxide (FeNO) measurements, lung function testing, and collection of fractionated exhaled breath condensate using a capnograph-based approach. The LTB₄ concentrations in the small airway or alveolar and large airway fractions were correlated to disease status, lung function impairment, and clinical parameters.

RESULTS

Children with asthma had significantly higher LTB₄ concentrations in the small airway or alveolar fraction than controls (5.58 pg/mL; 95% interquartile range [IQR], 2.0-11.77 pg/mL; vs 2.0 pg/mL; 95% IQR, 2.0-6.2 pg/mL; P = .003). No difference was found between the groups in the large airway fraction. Children with obstructive lung function impairment (forced expiratory volume in 1 second z score <-1.65) had increased small airway or alveolar LTB₄ concentrations compared with children without impairment (2.0 pg/mL; 95% IQR, 2.0-9.21 pg/mL; vs 18.32 pg/mL; 95% IQR, 3.7-23.02 pg/mL; P = .04). Children with asthma but without pathologic obstructive lung function still had higher LTB₄ concentrations than controls (5.57 pg/mL; 95% IQR, 2.00-10.60 pg/mL; vs 2.00 pg/mL; 95% IQR, 2.00-6.20 pg/mL; P = .01).

CONCLUSION

LTB₄ is detectable and elevated in the small airway or alveolar fraction of exhaled breath condensate in pediatric asthma. Because of the possibility of detecting elevated levels in patients without lung function impairment in controlled disease, it may be used as a noninvasive marker of small airways disease; however, future long-term studies are needed.

Chronic obstructive pulmonary disease and asthma-associated Proteobacteria, but not commensal Prevotella spp., promote Toll-like receptor 2-independent lung inflammation and pathology

Recent studies of healthy human airways have revealed colonization by a distinct commensal bacterial microbiota containing Gram-negative Prevotella spp. However, the immunological properties of these bacteria in the respiratory system remain unknown. Here we compare the innate respiratory immune response to three Gram-negative commensal Prevotella strains (Prevotella melaninogenica, Prevotella nanceiensis and Prevotella salivae) and three Gram-negative pathogenic Proteobacteria known to colonize lungs of patients with chronic obstructive pulmonary disease (COPD) and asthma (Haemophilus influenzae B, non-typeable Haemophilus influenzae and Moraxella catarrhalis). The commensal Prevotella spp. and pathogenic Proteobacteria were found to exhibit intrinsic differences in innate inflammatory capacities on murine lung cells in vitro. In vivo in mice, non-typeable H. influenzae induced severe Toll-like receptor 2 (TLR2)-independent COPD-like inflammation characterized by predominant airway neutrophilia, expression of a neutrophilic cytokine/chemokine profile in lung tissue, and lung immunopathology. In comparison, P. nanceiensis induced a diminished neutrophilic airway inflammation and no detectable lung pathology. Interestingly, the inflammatory airway response to the Gram-negative bacteria P. nanceiensis was completely TLR2-dependent. These findings demonstrate weak inflammatory properties of Gram-negative airway commensal Prevotella spp. that may make colonization by these bacteria tolerable by the respiratory immune system.

Disease models of chronic inflammatory airway disease: applications and requirements for clinical trials

PURPOSE OF REVIEW

This review will discuss methodologies and applicability of key inflammatory models of respiratory disease in proof of concept or proof of efficacy clinical studies. In close relationship with these models, induced sputum and inflammatory cell counts will be addressed for phenotype-directed drug development. Additionally, important regulatory aspects regarding noninvestigational medicinal products used in bronchial challenges or clinical inflammatory models of respiratory disease will be highlighted.

RECENT FINDINGS

The recognition of an ever increasing number of phenotypes and endotypes within conditions such as asthma and chronic obstructive pulmonary disease urges phenotyping of study populations already in early clinical phases of drug development. Apart from the choice of a relevant disease model, recent studies show that especially targeted therapies need to be tested in well defined disease subsets for adequate efficacy assessment. Noninvasive biomarkers, especially sputum inflammatory cell counts, aid phenotyping and are useful outcome measures for novel, targeted therapies.

SUMMARY

Disease phenotyping becomes increasingly important for efficient and cost-effective drug development and subsequent disease management. Inflammatory models of respiratory disease combined with sputum biomarkers are important tools in this approach.

Transcompartmental inflammatory responses in humans: IV versus endobronchial administration of endotoxin*

OBJECTIVES

Transcompartmental signaling during early inflammation may lead to propagation of disease to other organs. The time course and the mechanisms involved are still poorly understood. We aimed at comparing acute transcompartmental inflammatory responses in humans following lipopolysaccharide-induced pulmonary and systemic inflammation.

DESIGN

Randomized, double-blind, placebo-controlled, crossover study.

SETTING ICU SUBJECTS

Healthy male volunteers.

INTERVENTIONS

Fifteen volunteers (mean age, 23; SD, 2 yr) received Escherichia coli endotoxin (lipopolysaccharide, 4 ng/kg) IV or endobronchially on two different study days. Groups were evaluated by bronchoalveolar lavage at baseline (0 hr) and 2, 4, 6, 8, or 24 hours postchallenge. Cardiorespiratory variables were continuously recorded throughout the study day, and plasma and bronchoalveolar lavage fluid markers of inflammation were measured.

MEASUREMENTS AND MAIN RESULTS

IV endotoxin elicited a systemic inflammatory response with a time-dependent increase and peak in tumor necrosis factor-α, interleukin-6, and leukocyte counts (all p < 0.001). Furthermore, a delayed (6-8 hr) increase in bronchoalveolar lavage fluid interleukin-6 concentration (p < 0.001) and alveolar leukocyte count (p = 0.03) and a minor increase in bronchoalveolar lavage fluid tumor necrosis factor-α were observed (p = 0.06). Endobronchial endotoxin was followed by progressive alveolar neutrocytosis and increased bronchoalveolar lavage fluid tumor necrosis factor-α, interleukin-6, and albumin (all p < 0.001); a systemic inflammatory response was observed after 2-4 hours, with no change in plasma tumor necrosis factor-α.

CONCLUSIONS

Acute lung or systemic inflammation in humans is followed by a transcompartmental proinflammatory response, the degree and differential kinetics of which suggests that the propagation of inflammation may depend on the primary site of injury.

Advances in device and formulation technologies for pulmonary drug delivery

Inhaled pharmaceuticals are formulated and delivered differently according to the therapeutic indication. However, specific device-formulation coupling is often fickle, and new medications or indications also demand new strategies. The discontinuation of chlorofluorocarbon propellants has seen replacement of older metered dose inhalers with dry powder inhaler formulations. High-dose dry powder inhalers are increasingly seen as an alternative dosage form for nebulised medications. In other cases, new medications have completely bypassed conventional inhalers and been formulated for use with unique inhalers such as the Staccato® device. Among these different devices, integration of software and electronic assistance has become a shared trend. This review covers recent device and formulation advances that are forming the current landscape of inhaled therapeutics.

Emerging inhalation aerosol devices and strategies: where are we headed?

Novel inhaled therapeutics including antibiotics, vaccines and anti-hypertensives, have led to innovations in designing suitable delivery systems. These emerging design technologies are in urgent demand to ensure high aerosolisation performance, consistent efficacy and satisfactory patient adherence. Recent vibrating-mesh and software technologies have resulted in nebulisers that have remarkably accurate dosing and portability. Alternatively, dry powder inhalers (DPIs) have become highly favourable for delivering high-dose and single-dose drugs with the aid of advanced particle engineering. In contrast, innovations are needed to overcome the technical constrains in drug-propellant incompatibility and delivering high-dose drugs with pressurised metered dose inhalers (pMDIs). This review discusses recent and emerging trends in pulmonary drug delivery systems.

rs2243268 and rs2243274 of Interleukin-4 (IL-4) gene are associated with reduced risk for extrapulmonary and severe tuberculosis in Chinese Han children

Interleukin-4 (IL-4) and IL-10, which are produced by Th2 cells, serve as anti-inflammatory cytokines in the immune responses to tuberculosis (TB). In order to investigate the association between susceptibility to TB and single-nucleotide polymorphisms (SNPs) of the IL-4 and IL-10 genes, a case-control study including 346 TB patients and 374 healthy controls was performed in Chinese Han children in North China. Though no significant differences in the allelic and genotypic distributions of SNPs of these two genes were observed between control group and TB group, rs2243268-A and rs2243274-G of the IL-4 gene were associated with reduced risk of developing extrapulmonary tuberculosis (EPTB) (Prs2243268=0.005 and Prs2243274=0.004) and severe TB (Prs2243268=0.003 and Prs2243274=0.003). The haplotype comprising rs2243268-A and rs2243274-G was found to be a resistance factor against EPTB and severe TB. In addition, after stimulation with inactivated H37Rv, blood samples of the rs2243268 AA+AC carriers showed significantly reduced IL-10 production (P=0.045) compared to the CC carriers. In conclusion, rs2243268-A and rs2243274-G of the IL-4 gene were found to confer resistance to EPTB and severe TB in Chinese Han children.

Airway hyper-responsiveness in lipopolysaccharide-challenged common marmosets (Callithrix jacchus)

Animal models with a high predictive value for human trials are needed to develop novel human-specific therapeutics for respiratory diseases. The aim of the present study was to examine lung-function parameters in marmoset monkeys (Callithrix jacchus) that can be used to detect pharmacologically or provocation-induced AHR (airway hyper-responsiveness). Therefore a custom-made lung-function device that allows application of defined aerosol doses during measurement was developed. It was hypothesized that LPS (lipopolysaccharide)-challenged marmosets show AHR compared with non-challenged healthy subjects. Invasive plethysmography was performed in 12 anaesthetized orotracheally intubated and spontaneously breathing marmosets. Pulmonary data of R_L (lung resistance), C_dyn (dynamic compliance), EF₅₀ (mid-expiratory flow), P_oes (oesophageal pressure), MV (minute volume), respiratory frequency (f) and V_T (tidal volume) were collected. Measurements were conducted under baseline conditions and under MCh (methacholine)-induced bronchoconstriction. The measurement was repeated with the same group of animals after induction of an acute lung inflammation by intratracheal application of LPS. PDs (provocative doses) of MCh to achieve a certain increase in R_L were significantly lower after LPS administration. AHR was demonstrated in the LPS treated compared with the naïve animals. The recorded lung-function data provide ground for pre-clinical efficacy and safety testing of anti-inflammatory substances in the common marmoset, a new translational NHP (non-human primate) model for LPS-induced lung inflammation.

The stimulated innate resistance event in Bordetella pertussis infection is dependent on reactive oxygen species production

The exacerbated induction of innate immune responses in airways can abrogate diverse lung infections by a phenomenon known as stimulated innate resistance (StIR). We recently demonstrated that the enhancement of innate response activation can efficiently impair Bordetella pertussis colonization in a Toll-like receptor 4 (TLR4)-dependent manner. The aim of this work was to further characterize the effect of lipopolysaccharide (LPS) on StIR and to identify the mechanisms that mediate this process. Our results showed that bacterial infection was completely abrogated in treated mice when the LPS of B. pertussis (1 μg) was added before (48 h or 24 h), after (24 h), or simultaneously with the B. pertussis challenge (10(7) CFU). Moreover, we detected that LPS completely cleared bacterial infection as soon as 2 h posttreatment. This timing suggests that the observed StIR phenomenon should be mediated by fast-acting antimicrobial mechanisms. Although neutrophil recruitment was already evident at this time point, depletion assays using an anti-GR1 antibody showed that B. pertussis clearance was achieved even in the absence of neutrophils. To evaluate the possible role of free radicals in StIR, we performed animal assays using the antioxidant N-acetyl cysteine (NAC), which is known to inactivate oxidant species. NAC administration blocked the B. pertussis clearance induced by LPS. Nitrite concentrations were also increased in the LPS-treated mice; however, the inhibition of nitric oxide synthetases did not suppress the LPS-induced bacterial clearance. Taken together, our results show that reactive oxygen species (ROS) play an essential role in the TLR4-dependent innate clearance of B. pertussis.