A chitinase-like protein in the lung and circulation of patients with severe asthma

Phenotype of asthma related with high serum periostin levels

BACKGROUND

Asthma is a heterogeneous disease composed of various phenotypes. Periostin, a molecule inducible with interleukin (IL)-4 or IL-13 in bronchial epithelial cells, is a biomarker of "TH2-high" asthma. The objective of this study is to examine whether the serum periostin concentrations are correlated with the severity, specific phenotype(s), or comorbidity of asthma.

METHODS

Serum concentrations of periostin were measured in 190 Japanese asthmatic patients and 11 healthy controls. The protocol was registered under UMIN 000002980 in the clinical trial registry.

RESULTS

The serum concentrations of periostin were significantly higher (P = 0.014) in asthmatics [70.0 (54.0-93.5) ng/ml] than in healthy subjects [57.0 (39.0-63.0) ng/ml], though we found no correlation between serum periostin concentrations and treatment steps required to control asthma. To characterize "high-periostin" phenotype(s), the patients with asthma were divided among tertiles based on the serum concentrations of periostin. The high-periostin group was older at onset of asthma (P = 0.04), had a higher prevalence of aspirin intolerance (P = 0.04) or concomitant nasal disorders (P = 0.03-0.001), higher peripheral eosinophil counts (P < 0.001), and lower pulmonary function (P = 0.02-0.07). The serum concentrations of periostin were particularly high in asthmatic patients complicated by chronic rhinosinusitis with nasal polyps and olfactory dysfunction. In contrast, neither atopic status, control status of asthma, nor quality of life were related with the "high-periostin" phenotype.

CONCLUSION

Elevated periostin concentrations in serum were correlated with a specific phenotype of eosinophilic asthma, late-onset and often complicated by obstructive pulmonary dysfunction and nasal disorders.

Neutrophil-to-lymphocyte ratio, calprotectin and YKL-40 in patients with chronic obstructive pulmonary disease: correlations and 5-year mortality - a cohort study

Background

Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation and progressive decline in pulmonary function. Neutrophil-to-lymphocyte ratio (NLR), YKL-40 and calprotectin are biomarkers of inflammation and predict mortality in patients with different inflammatory diseases. We aimed to investigate the correlation between levels of these three biomarkers and neutrophil granulocyte and lymphocyte count in patients with moderate to very severe COPD stratified by use of systemic glucocorticoids. Furthermore, we studied the ability of these biomarkers to predict all-cause mortality.

Methods

386 patients with moderate to very severe COPD were followed prospectively for 10 years. Patients were divided into two groups according to systemic glucocorticoid use at baseline. Correlations between biomarkers were assessed by Spearman’s Rho, and mortality was evaluated in uni- and multivariate Cox regression analyses with hazard ratios (HR) and 95% confidence intervals (CI).

Results

Plasma calprotectin was positively correlated with neutrophil granulocyte count and NLR. No significant association was found between plasma YKL-40 and the cellular biomarkers, irrespective of glucocorticoid treatment. In the group not treated with systemic glucocorticoids, plasma calprotectin [HR 1.002 (95% CI 1.000 – 1.004)], NLR [HR 1.090 (1.036 – 1.148)] and lymphocyte count [HR 0.667 (0.522 – 0.851)] were significantly associated with higher mortality. In the group treated with systemic glucocorticoids, higher plasma YKL-40 was significantly associated with mortality in univariate Cox regression analysis [HR 1.006 (1.003 – 1.008)].

Conclusions

Calprotectin was related to neutrophil granulocyte count and NLR in patients with moderate to very severe COPD in stable phase and not in treatment with systemic glucocorticoids. Lymphopenia, higher plasma calprotectin and higher NLR were independent predictors of increased all-cause mortality in this group. Our data also suggests that treatment with systemic glucocorticoids has a significant impact on the ability of inflammatory biomarkers to predict all-cause mortality.

Trial registration

ClinicalTrials.gov NCT00132860.

IL-17 and neutrophils: unexpected players in the type 2 immune response

The study of immunity to helminth infection has been central to understanding the function of type 2 cytokines and their targets. Although type 2 cytokines are considered anti-inflammatory and promote tissue repair, they also contribute to allergy and fibrosis. Here, we utilise data from helminth infection models, to illustrate that IL-17 and neutrophils, typically associated with pro-inflammatory responses, are intimately linked with type 2 immunity. Neutrophils work with IL-4Rα-activated macrophages to control incoming larvae but this comes at a cost of enhanced tissue damage. Chitinase like proteins (CLPs) bridge these diverse outcomes, inducing both protective IL-17 and reparative Th2 responses. Dysregulation of CLPs, IL-17 and neutrophils likely contribute to disease severity and pathology associated with type 2 immunity.

Cross-talk between human mast cells and bronchial epithelial cells in plasminogen activator inhibitor-1 production via transforming growth factor-β1

Previous reports suggest that plasminogen activator inhibitor-1 (PAI-1) promotes airway remodeling and that human and mouse mast cells (MCs) are an important source of PAI-1. In the present study we investigated MC-epithelial cell (EC) interactions in the production of PAI-1. We stimulated the human MC line LAD2 with IgE-receptor cross-linking and collected the supernatants. We incubated the human bronchial EC line BEAS-2B with the LAD2 supernatants and measured the level of PAI-1. When the supernatants from IgE-stimulated LAD2 were added to BEAS-2B, there was a significant enhancement of PAI-1 production by BEAS-2B. When we treated the MC supernatants with a transforming growth factor (TGF)-β1 neutralizing antibody, the MC-derived induction of PAI-1 from BEAS-2B was completely abrogated. Although TGF-β1 mRNA was constitutively expressed in resting LAD2, it was not highly induced by IgE-mediated stimulation. Nonetheless, active TGF-β1 protein was significantly increased in LAD2 after IgE-mediated stimulation. Active TGF-β1 produced by primary cultured human MCs was significantly reduced in the presence of a chymase inhibitor, suggesting a role of MC chymase as an activator of latent TGF-β1. This study indicates that stimulation of human MCs by IgE receptor cross-linking triggers activation of TGF-β1, at least in part via chymase, which in turn induces the production of PAI-1 by bronchial ECs. Our data suggest that human MCs may play an important role in airway remodeling in asthma as a direct source of PAI-1 and by activating bronchial ECs to produce further PAI-1 via a TGF-β1-mediated activation pathway.

The role of chitin, chitinases, and chitinase-like proteins in pediatric lung diseases

Chitin, after cellulose, the second most abundant biopolymer on earth, is a key component of insects, fungi, and house-dust mites. Lower life forms are endowed with chitinases to defend themselves against chitin-bearing pathogens. Unexpectedly, humans were also found to express chitinases as well as chitinase-like proteins that modulate immune responses. Particularly, increased levels of the chitinase-like protein YKL-40 have been associated with severe asthma, cystic fibrosis, and other inflammatory disease conditions. Here, we summarize and discuss the potential role of chitin, chitinases, and chitinase-like proteins in pediatric lung diseases.

YKL-40 protein correlates with the phenotype of asthma

Purpose

YKL-40 is a chitinase-like protein found to correlate with asthma as well as numerous infectious and autoimmune diseases or cancer. The aim of the present study was to investigate the role of YKL-40 as a possible marker of asthma and its associations with factors differentiating phenotypes of asthma.

Methods

The study group comprised 167 patients, including 116 women and 51 men aged 18–88 years with chronic asthma. The control group comprised 81 healthy individuals, including 50 women and 31 men aged 19–86 years. In every participant, medical history was taken; spirometry and skin prick tests were performed. YKL-40 was determined in sera by means of ELISA test.

Results

Mean serum YKL-40 level was 59.7 ng/ml (53.6–65.7 ng/ml; 95 % CI) with significant difference between asthmatics and healthy controls (mean values: 66.8 ± 53.8 vs. 44.9 ± 29.4 ng/ml; p < 0.001). In asthmatics, the level was significantly higher in subgroup with poor control of symptoms and exacerbations (91.8 ± 57.1 ng/ml) compared to stable asthmatics (59.6 ± 50.8 ng/ml; p < 0.001) as well as in atopic compared to non-atopic asthmatics (77.2 ± 53.9 vs. 61.1 ± 57.8 ng/ml; p < 0.001). Mean YKL-40 level in obese asthmatics was 135.6 ng/ml compared to 50.0 ng/ml in non-obese (p < 0.001). When phenotypes of early-onset atopic, late-onset non-atopic, and obesity-related asthma were compared, YKL-40 levels were 80.62 ± 46.9, 51.5 ± 24.9, and 168.1 ± 71.5 ng/ml, respectively (p < 0.05).

Conclusion

Although YKL-40 is not a specific marker for asthma, it correlates with some clinical features such as exacerbation, level of control, atopy, and obesity.

Exacerbating factors induce different gene expression profiles in peripheral blood mononuclear cells from asthmatics, patients with chronic obstructive pulmonary disease and healthy subjects

BACKGROUND

Despite several common phenotypic features, chronic obstructive pulmonary disease (COPD) and severe asthma differ with regard to their causative factors and pathophysiology. Both diseases may be exacerbated by environmental factors, however, the molecular profiles of disease episodes have not been comprehensively studied. We identified differences in gene and protein expression profiles expressed by peripheral blood mononuclear cells (PBMC) of COPD patients, patients with atopic asthma and healthy subjects when challenged with exacerbating factors in vitro: lipopolysaccharide (LPS), house dust mite (HDM) and cat allergen.

METHODS

PBMC isolated from patients with severe atopic asthma and COPD, as well as healthy subjects were stimulated with rDer p 1 DG, rFel d 1 DG and LPS. The changes in the expression of 47 genes belonging to five groups (phospholipase A2, eicosanoids, transcription factors, cytokines and airway remodeling) were studied using TaqMan low density array cards. Immunoblotting was used to study relative protein expression.

RESULTS

rDer p 1 significantly up-regulated the expression of PLA2G4A, PLA2G6, PLA2G15, CYSLTR1, LB4R2, PTGS1, PTGS2, FOXP1, GATA3, HDAC2, IREB2, PPARG, STAT4, TSLP and CHI3L1 genes in asthmatics in comparison to healthy subjects. LPS induced significant expression of ANXA1 and LTA4H in asthmatics when compared to COPD patients and healthy subjects. SOX6,STAT4 and IL1RL1 were induced in COPD after LPS stimulation. Analysis of protein expression revealed a pattern similar to mRNA expression.

CONCLUSIONS

LPS-induced exacerbation of asthma and COPD is characterized by differential expression of selected genes in PBMC. HDM allergen changed the expression profile of inflammatory genes between patients with asthma of atopic origin and healthy controls.

Dipeptidyl-peptidase 10 as a genetic biomarker for the aspirin-exacerbated respiratory disease phenotype

BACKGROUND

Aspirin-exacerbated respiratory disease (AERD) is an endotype of severe and eosinophilic adult asthma characterized by chronic rhinosinusitis with nasal polyps and hypersensitivity to aspirin and/or nonsteroidal anti-inflammatory drugs. A genetic contribution of dipeptidyl-peptidase 10 (DPP10) to asthma susceptibility and lung function decline has been reported. However, little is known about the role of DPP10 in the pathogenesis of AERD.

OBJECTIVE

To identify genetic variants of DPP10 that confer susceptibility to AERD or severe asthma.

METHODS

A case-control association study of DPP10 gene polymorphisms was performed in 3 groups of patients: 274 with AERD, 272 with aspirin-tolerant asthma, and 99 normal healthy controls. The rs17048175 single-nucleotide polymorphism was targeted based on a preliminary genomewide association study using an Affymetrix genomewide human single-nucleotide polymorphism array in a Korean population. DPP10, 15-hydroxyeicosatetraenoic acid, and YKL-40/chitinase-3-like protein were measured by enzyme-linked immunosorbent assay in sera taken from the study subjects.

RESULTS

There was a significant association between rs17048175 and the AERD phenotype, but not with aspirin-tolerant asthma. The DPP10 level was significantly higher in sera from patients with AERD compared with patients with aspirin-tolerant asthma and control subjects (P = .021 and P < .001, respectively). In addition, there was a significant difference of serum DPP10 level according to the single-nucleotide polymorphism (P = .001). Serum DPP10 level showed a strong correlation with 15-hydroxyeicosatetraenoic acid (r = 0.226, P = .017) and YKL-40 (r = 0.364, P = .004).

CONCLUSION

This study suggests a genetic contribution of rs17048175 to DPP10 in eosinophilic inflammation induction in the airways and to AERD susceptibility.

YKL-40 is correlated with FEV1 and the asthma control test (ACT) in asthmatic patients: influence of treatment

Background

YKL-40 is also called chitinase-3-like-1 (CHI3L1) protein and may be a marker for asthma. The aims of the present study were to investigate whether serum YKL-40 levels are stable or decreased in patients with asthma after appropriate treatment and to evaluate the correlation of YKL-40 levels with lung function and asthma control test (ACT) results.

Methods

A total of 103 asthmatic patients (mean age 33.1 ± 0.9 years) with diagnosed asthma were enrolled in our study. All patients underwent a detailed clinical examination and completed the ACT questionnaire, serum YKL-40 measurement, and spirometry before (visit 1) and 8 weeks after initiation of treatment (visit 2).

Results

At the follow-up, the median serum YKL-40 level was significantly decreased compared to the levels at visit 1 (75.2 [55.8-86.8] ng/ml versus 54.5 [46.4-58.4] ng/ml, p < 0.001). The serum YKL-40 level was negatively correlated with %FEV₁ (r = -0.37, p < 0.001) and ACT score (r = -0.26, p = 0.007) at visit 1. The change in serum YKL-40 levels between the visits was significantly correlated with changes in FEV₁ (r = -0.28, p = 0.006) and ACT score (r = -0.22, p = 0.037). Patients with elevated YKL-40 levels had significantly greater corticosteroid use than patients with lower levels.

Conclusions

YKL-40 was reduced in the serum of asthmatic patients after appropriate treatment, and the levels correlated with improvements in %FEV₁ and ACT. High levels of serum YKL-40 may be refractory to current asthma treatments.

Trial registration

ChiCTR-OCC-13003316

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2466-15-1) contains supplementary material, which is available to authorized users.

Identification of neutrophil activation markers as novel surrogate markers of CF lung disease

Background and aims

Cystic Fibrosis (CF) lung disease is characterized by progressively declining lung function and represents a major factor contributing to the high morbidity and mortality associated with CF. However, apart from spirometry, respiratory disease surrogate markers reliably indicating CF lung disease and the occurrence of pulmonary exacerbations (PEx) are still lacking. Within this study, we aimed to identify new experimental biomarkers for the detection of CF lung disease.

Methods

54 adult and 26 pediatric CF patients were included in the study and serum concentrations of MMP-1, -2, -8, -9, -13, TIMP-1, TIMP-2, YKL-40, hyaluronic acid, procollagen III peptide were quantified by ELISA. CF lung disease was diagnosed by lung function test, PEx was defined based on a clinical scoring established by Rosenfeld in 2001.

Results

Adults and children with moderate to severe CF lung disease exhibited significantly increased serum expression of MMP-8, MMP-9, YKL-40 and TIMP-1. Further, MMP-8, MMP-9 and YKL-40 were significantly increased in adult CF patients suffering from PEx compared to those without clinical signs of respiratory exacerbation. MMP-8, MMP-9, YKL-40, and TIMP-1 serum levels were unaffected by the presence or absence of CF liver disease or pancreatic insufficiency.

Conclusions

MMP-8, MMP-9, and YKL-40 might serve as novel non-invasive biomarkers of CF lung disease and PEx.

Distinct macrophage phenotypes in allergic and nonallergic lung inflammation

Chronic exposure to farm environments is a risk factor for nonallergic lung disease. In contrast to allergic asthma, in which type 2 helper T cell (Th2) activation is dominant, exposure to farm dust extracts (FDE) induces Th1/Th17 lung inflammation, associated with neutrophil infiltration. Macrophage influx is a common feature of both types of lung inflammation, allergic and nonallergic. However, macrophage functions and phenotypes may vary according to their polarized state, which is dependent on the cytokine environment. In this study, we aimed to characterize and quantify the lung macrophage populations in two established murine models of allergic and nonallergic lung inflammation by means of fluorescence-activated cell sorting and immunohistochemistry. We demonstrated that, whereas in allergic asthma M2-dominant macrophages predominated in the lungs, in nonallergic inflammation M1-dominant macrophages were more prevalent. This was confirmed in vitro using a macrophage cell line, where FDE exerted a direct effect on macrophages, inducing M1-dominant polarization. The polarization of macrophages diverged depending on the exposure and inflammatory status of the tissue. Interfering with this polarization could be a target for treatment of different types of lung inflammation.

Novel biomarkers for asthma stratification and personalized therapy

A stepwise pharmacological treatment is currently recommended for all asthma patients and is personalized mainly on disease severity, aiming for the lowest disease-controlling step. Nevertheless, asthma comprises several related pathologies with similar clinical manifestations resulting from distinct underlying mechanisms. Therefore novel biomarkers could lead to asthma stratification and thus improve upon the current stepwise approach. The aim of this review is to update the reader with regard to different assays proposed in the recent asthma literature for measuring potential biomarkers for patient stratification and treatment personalization. Promising biomarkers are sputum eosinophils, serum periostin and exhaled nitric oxide. Periostin could differentiate between Th2-high and Th2-low asthma (Th2-high patients are more responsive to glucocorticoids) and the less-defined asthma types which often present a therapeutic challenge. Several other biomarkers, mainly cytokines, leukotrienes and exhaled air components, can be quantified in body fluids and exhaled breath and could also be useful for asthma stratification.

New treatment and markers of prognosis for idiopathic pulmonary fibrosis: lessons learned from translational research

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial lung disease with increasing prevalence, high mortality rates and poor treatment options. The diagnostic process is complex and often requires an interdisciplinary approach between different specialists. Information gained over the past 10 years of intense research resulted in improved diagnostic algorithms, a better understanding of the underlying pathogenesis and the development of new therapeutic options. Specifically, the change from the traditional concept that viewed IPF as a chronic inflammatory disorder to the current belief that is primarily resulting from aberrant wound healing enabled the identification of novel treatment targets. This increased the clinical trial activity dramatically and resulted in the approval of the first IPF-specific therapy in many countries. Still, the natural history and intrinsic behavior of IPF are very difficult to predict. There is an urgent need for new therapies and also for development and validation of prognostic markers that predict disease progression, survival and also response to antifibrotic drugs. This review provides an up to date summary of the most relevant clinical trials, novel therapeutic drug targets and outlines a spectrum of potential prognostic biomarkers for IPF.

Antigen-specific over-expression of human cartilage glycoprotein 39 on CD4+ CD25+ forkhead box protein 3+ regulatory T cells in the generation of glucose-6-phosphate isomerase-induced arthritis

Human cartilage gp-39 (HC gp-39) is a well-known autoantigen in rheumatoid arthritis (RA). However, the exact localization, fluctuation and function of HC gp-39 in RA are unknown. Therefore, using a glucose-6-phosphate isomerase (GPI)-induced model of arthritis, we investigated these aspects of HC gp-39 in arthritis. The rise in serum HC gp-39 levels was detected on the early phase of GPI-induced arthritis (day 7) and the HC gp-39 mRNA was increased significantly on splenic CD4(+) T cells on day7, but not on CD11b(+) cells. Moreover, to identify the characterization of HC gp-39(+) CD4(+) T cells, we assessed the analysis of T helper (Th) subsets. As a result, HC gp-39 was expressed dominantly in CD4(+) CD25(+) forkhead box protein 3 (FoxP3)(+) refulatory T cells (T(reg)), but not in Th1, Th2 or Th17 cells. Furthermore, to investigate the effect of HC gp-39 to CD4(+) T cells, T cell proliferation assay and cytokine production from CD4(+) T cells using recombinant HC gp-39 was assessed. We found that GPI-specific T cell proliferation and interferon (IFN)-γ or interleukin (IL)-17 production were clearly suppressed by addition of recombinant HC gp-39. Antigen-specific over-expression of HC gp-39 in splenic CD4(+) CD25(+) FoxP3(+) T(reg) cells occurs in the induction phase of GPI-induced arthritis, and addition of recombinant HC gp-39 suppresses antigen-specific T-cell proliferation and cytokine production, suggesting that HC gp-39 in CD4(+) T cells might play a regulatory role in arthritis.

Establishment of a quantitative PCR system for discriminating chitinase-like proteins: catalytically inactive breast regression protein-39 and Ym1 are constitutive genes in mouse lung

BACKGROUND

Mice and humans produce chitinase-like proteins (CLPs), which are highly homologous to chitinases but lack chitinolytic activity. Mice express primarily three CLPs, including breast regression protein-39 (BRP-39) [chitinase 3-like-1 (Chi3l1) or 38-kDa glycoprotein (gp38k)], Ym1 (Chi3l3) and Ym2 (Chi3l4). Recently, CLPs have attracted considerable attention due to their increased expression in a number of pathological conditions, including asthma, allergies, rheumatoid arthritis and malignant tumors. Although the exact functions of CLPs are largely unknown, the significance of their increased expression levels during pathophysiological states needs to be determined. The quantification of BRP-39, Ym1 and Ym2 is an important step in gaining insight into the in vivo regulation of the CLPs.

METHODS

We constructed a standard DNA for quantitative real-time PCR (qPCR) by containing three CLPs target fragments and five reference genes cDNA in a one-to-one ratio. We evaluated this system by analyzing the eight target cDNA sequences. Tissue cDNAs obtained by reverse transcription from total RNA from four embryonic stages and eight adult tissues were analyzed using the qPCR system with the standard DNA.

RESULTS

We established a qPCR system detecting CLPs and comparing their expression levels with those of five reference genes using the same scale in mouse tissues. We found that BRP-39 and Ym1 were abundant in the mouse lung, whereas Ym2 mRNA was abundant in the stomach, followed by lung. The expression levels of BRP-39 and Ym1 in the mouse lung were higher than those of two active chitinases and were comparable to glyceraldehyde-3-phosphate dehydrogenase, a housekeeping gene which is constitutively expressed in all tissues.

CONCLUSION

Our results indicate that catalytically inactive BRP-39 and Ym1 are constitutive genes in normal mouse lung.

Adult asthma biomarkers

PURPOSE OF REVIEW

A variety of novel asthma treatments have been developed based on phenotypes, and the clinical trial results show promising responses. This review summarizes the current knowledge of biomarkers for the determination of asthma phenotypes.

RECENT FINDINGS

Eosinophilic inflammation is the most focused phenotype because most novel asthma treatments have targeted T-helper type 2 (Th2) pathway. Fractional-exhaled nitric oxide (FeNO) is a new method that represents an eosinophilic airway inflammation with a significant correlation with sputum eosinophilia and asthma severity instead of sputum eosinophil count that easily influenced by corticosteroid therapy. However, some reports indicated the discordance between treatment response or adjustment and FeNO levels. Serum periostin is a strong serum biomarker for eosinophilic airway inflammation and an indicator of Th2-targeted therapy (such as lebrikizumab or omalizumab) and airflow limitation. YKL-40 is associated with asthma severity and airway remodeling. In addition, genetic and metabolomic approaches have been made to determine asthma phenotypes and severity.

SUMMARY

Biomarkers such as FeNO and serum periostin represent eosinophilic airway inflammation, together with eosinophil-derived neurotoxin and osteopontin (OPN) needed more replication studies. Periostin, YKL-40, OPN and some metabolites (choline, arginine, acetone and protectin D1) are related to asthma severity and airflow limitation.

Axl receptor blockade protects from invasive pulmonary aspergillosis in mice

Aspergillus fumigatus is a sporulating fungus found ubiquitously in the environment, which is quickly contained in the immunocompetent host but can cause lethal invasive aspergillosis in the immunocompromised host. We have recently demonstrated that Axl (one member of the Tyro3, Axl, Mertk receptor family) is a key regulator of antiviral immune responses in the lung. In this study, we investigated the role of Axl in antifungal immunity in a model of invasive pulmonary aspergillosis (IPA). In this model, Aspergillus fumigatus conidia were administered into the lungs of neutrophil-depleted mice, and the mice were monitored for survival, lung inflammatory response, and fungal clearance. The lethal effect of IPA was significantly reduced in anti-Axl mAb-treated mice compared with IgG control-treated mice. Targeting Axl significantly inhibited pulmonary inflammation, including the expression of IL-1β, IL-6, TNF-α, and chitinase-like proteins in whole lung. Further, anti-Axl mAb treatment significantly increased M1 macrophages that highly expressed inducible NO synthase and decreased M2 macrophages that expressed Arginase 1 and were found in inflammatory zone protein (Fizz1). More importantly, anti-Axl mAb treatment significantly increased the number of IFN-γ-producing T cells and NK cells compared with the IgG control group during IPA. Together, our results demonstrate that the Axl mAb treatment is protective during invasive aspergillosis in neutropenic mice. Collectively, these data suggest a potential deleterious role for Axl during primary immune responses directed against A. fumigatus and novel therapeutic strategy for IPA.

Serum YKL-40 concentrations are elevated and correlated with disease severity in patients with obstructive sleep apnea syndrome

Abstract Inflammation plays a critical role in the pathogenesis of obstructive sleep apnea syndrome (OSAS). YKL-40 is a novel biomarker of systemic inflammation. We aim to detect serum YKL-40 concentrations in OSAS patients and to clarify their relationship with clinical severity of the disease. We enrolled 159 OSAS patients and 104 healthy controls. The presence and severity of OSAS was assessed by Apnea-hypopnea index (AHI). Serum YKL-40 concentrations were detected by enzyme-linked immunosorbent assay (ELISA). We demonstrated that serum YKL-40 concentrations were significantly elevated in OSAS patients than those in controls. Multivariate logistic regression including all variables revealed that YKL-40 was the significant and independent predictor for the present of OSAS. In OSAS patients, there is a significant positive correlation between increments in serum YKL-40 concentrations and severity of OSAS. Serum YKL-40 concentrations were independently and significantly correlated with AHI scores. These results suggest that YKL-40 could be used as a potential biomarker for predicting the development and progression of OSAS.

The effects of lebrikizumab in patients with mild asthma following whole lung allergen challenge

Background

Interleukin 13 (IL13) is a T-helper type 2 (Th2) cytokine associated with inflammation and pathology in allergic diseases such as bronchial asthma. We have shown that treatment with lebrikizumab, an anti-IL13 monoclonal antibody, significantly improves prebronchodilator forced expiratory volume in 1 s (FEV₁) in a subset of subjects with uncontrolled asthma.

Objective

To evaluate efficacy and safety of lebrikizumab in subjects with mild asthma who underwent bronchial allergen challenge.

Methods

Twenty-nine subjects were randomized 1: 1–5 mg/kg lebrikizumab (n = 13) or placebo (n = 16) administered subcutaneously every 4 weeks over 12 weeks, a total of four doses. Primary efficacy outcome was late asthmatic response (LAR) at Week 13, defined as area under the curve of FEV₁ measured 2–8 h following inhaled allergen challenge. Serum biomarkers were measured to verify IL13 pathway inhibition and identify patients with an increased response to lebrikizumab.

Results

At Week 13, the LAR in lebrikizumab subjects was reduced by 48% compared with placebo subjects, although this was not statistically significant (95% confidence interval, −19%, 90%). Exploratory analysis indicated that lebrikizumab-treated subjects with elevated baseline levels of peripheral blood eosinophils, serum IgE, or periostin exhibited a greater reduction in LAR compared with subjects with lower baseline levels of these biomarkers. Lebrikizumab exerted systemic effects on markers of Th2 inflammation, reducing serum immunoglobulin E (IgE), chemokine ligands 13 and 17 by approximately 25% (P < 0.01). Lebrikizumab was well tolerated.

Conclusion and Clinical Relevance

Lebrikizumab reduced the LAR in subjects with mild asthma. Clinical trial number NCT00781443.

CHI3L1 plays a role in cancer through enhanced production of pro-inflammatory/pro-tumorigenic and angiogenic factors

Elevated serum levels of a glycoprotein known as chitinase-3-like protein 1 (CHI3L1) have been correlated with poor prognosis and shorter survival of patients with cancer and inflammatory diseases. The biological and physiological functions of CHI3L1 in cancer have not yet been completely elucidated. In this review, we describe the role of CHI3L1 in inducing pro-inflammatory/pro-tumorigenic and angiogenic factors that could promote tumor growth and metastasis.

CHI3L1 polymorphisms associate with asthma in a Taiwanese population

BACKGROUND

A genome-wide association study uncovered Chitinase 3 like 1 (CHI3L1) as a candidate gene for asthma susceptibility. CHI3L1, which encodes the YKL-40 protein, is associated with asthma in Western European and American populations and with atopy in a Korean population. However, asthma-associated polymorphisms remain unknown for a Taiwanese population.

METHODS

We enrolled 628 adult asthmatic patients and 1:1 age-sex matched community-based controls in southern Taiwan and performed a combined effect sizes analysis to test if CHI3L1 polymorphisms were related to genetic risks for asthma in the Asian population. Ten tagSNP polymorphisms for the CHI3L1 gene were selected from the HapMap database and genotyped using a TaqMan allelic discrimination assay.

RESULTS

Adjusted odds ratios of the CHI3L1 rs1538372 CC genotype (aOR = 1.97, 95% CI: 1.23-3.14) and the rs10399931 GG genotype (aOR = 1.77, 95% CI: 1.13-2.77) were significantly associated with asthma in the Taiwanese populations. Predictive values of forced expiratory volume in the first second of the forced vital capacity (12.37%, P = 0.03) and of forced vital capacity (12.10%, P = 0.036) decreased in conjunction with an increase in YKL-40 levels among CHI3L1 rs1538372 CC carriers; these values were 16.1% (P = 0.004) and 14.5% (P = 0.011), respectively, among CHI3L1 rs10399931 GG carriers. Furthermore, steroid use by asthma patients did not affect serum YKL-40 levels, but both polymorphisms had significant effects on YKL-40 levels in asthma patients who used steroids.

CONCLUSIONS

Our findings suggest that the CHI3L1 polymorphisms rs1538372 and rs10399931 can be used as genetic markers for predicting asthma risk in the Taiwanese population.

Increased expression of YKL-40 in mild and moderate/severe persistent allergic rhinitis and its possible contribution to remodeling of nasal mucosa

BACKGROUND

Prominent expression of YKL-40 has been associated with pathological conditions characterized by tissue remodeling. We determined the expression level and distribution pattern of YKL-40 in allergic nasal mucosa and evaluated the effect of YKL-40 on the proliferation and migration of fibroblasts, the production of the mediators related to tissue remodeling, and collagen production. Additionally, the cytokine-driven regulation of YKL-40 expression was evaluated in cultured epithelial cells.

METHODS

The expression of YKL-40 in normal, mild, and moderate/severe allergic nasal mucosa was evaluated using real-time polymerase chain reaction (PCR), Western blot, and immunohistochemistry. Fibroblast migration was observed using a scratch wound method, and proliferation was determined by the MTT methods. Expression of proteoglycans, transforming growth factor (TGF) beta1, MMP2, MMP9, TIMP1, TIMP2, and collagen concentration were analyzed in fibroblasts treated with YKL-40. The expression levels of YKL-40 in cultured epithelial cells were examined after stimulation with mediators including Th2 cytokines, interferon (IFN)gamma, and TNF-alpha with real-time PCR and ELISA.

RESULTS

The expression of YKL-40 was up-regulated in allergic rhinitis and distributed in superficial epithelium, submucosal glands, and vascular endothelium, in addition to infiltrating cells. TGF-beta1, TIMP1, MMP9, and biglycan were up-regulated in fibroblasts on stimulation with YKL-40, accompanying increased proliferation and migration, and collagen production. IL-13, IFN-gamma, and TNF-alpha induced the increased production of YKL-40 in cultured epithelial cells.

CONCLUSION

YKL-40 is up-regulated in mild and moderate/severe persistent allergic rhinitis, and its expression can be regulated differentially by different cytokines, possibly contributing to the remodeling of nasal mucosa in allergic rhinitis.

Graphene oxide attenuates Th2-type immune responses, but augments airway remodeling and hyperresponsiveness in a murine model of asthma

Several lines of evidence indicate that exposure to nanoparticles (NPs) is able to modify airway immune responses, thus facilitating the development of respiratory diseases. Graphene oxide (GO) is a promising carbonaceous nanomaterial with unique physicochemical properties, envisioned for a multitude of medical and industrial applications. In this paper, we determined how exposure to GO modulates the allergic pulmonary response. Using a murine model of ovalbumin (OVA)-induced asthma, we revealed that GO, given at the sensitization stage, augmented airway hyperresponsiveness and airway remodeling in the form of goblet cell hyperplasia and smooth muscle hypertrophy. At the same time, the levels of the cytokines IL-4, IL-5, and IL-13 were reduced in broncho-alveolar lavage (BAL) fluid in GO-exposed mice. Exposure to GO during sensitization with OVA decreased eosinophil accumulation and increased recruitment of macrophages in BAL fluid. In line with the cytokine profiles, sensitization with OVA in the presence of GO stimulated the production of OVA-specific IgG2a and down-regulated the levels of IgE and IgG1. Moreover, exposure to GO increased the macrophage production of the mammalian chitinases, CHI3L1 and AMCase, whose expression is associated with asthma. Finally, molecular modeling has suggested that GO may directly interact with chitinase, affecting AMCase activity, which has been directly proven in our studies. Thus, these data show that GO exposure attenuates Th2 immune response in a model of OVA-induced asthma, but leads to potentiation of airway remodeling and hyperresponsiveness, with the induction of mammalian chitinases.

Plasma levels of the proinflammatory chitin-binding glycoprotein YKL-40, variation in the chitinase 3-like 1 gene (CHI3L1), and incident cardiovascular events

Background

YKL‐40, encoded by the chitinase 3‐like 1 (CHI3L1) gene, is a chitinase‐like protein involved in innate immune function hypothesized to play a role in the progression of atherosclerosis that may have differential roles in myocardial infarction (MI), as compared to stroke.

Methods and Results

In a nested case‐control study conducted within a prospective cohort of 23 294 initially healthy women of European ancestry, we (1) measured plasma concentration of YKL‐40 among 359 participants who subsequently developed cardiovascular events and among 359 age‐, smoking‐, and hormone replacement therapy–matched participants who remained free of disease during 17 years of follow‐up, (2) compared effects of YKL‐40 on vascular risk to that associated with 3 alternative inflammatory biomarkers (high‐sensitivity C‐reactive protein) ([hsCRP], soluble intracellular adhesion molecule 1, and fibrinogen), and (3) evaluated the role of 41 single‐nucleotide polymorphisms (SNPs) in the chitinase 3‐like 1 gene (CHI3L1) as determinants of YKL‐40 levels and incident vascular events. YKL‐40 levels were higher in women with hypertension, diabetes, and obesity and correlated modestly with high‐density lipoprotein cholesterol, triglycerides, and hsCRP, but not with low‐density lipoprotein cholesterol. Baseline YKL‐40 level was significantly associated with incident thromboembolic stroke with a magnitude of effect (a 40% per quartile increase in odds ratio [OR], P=0.019) comparable to that of hsCRP (a 52% per quartile increase in OR, P=0.006). By contrast, no significant association was observed between YKL‐40 and incident MI. Genetic variation in CHI3L1 was strongly associated with YKL‐40 levels; however, in this sample set, we did not observe a statistically significant association between genotype and future vascular events.

Conclusions

Among initially healthy U.S. women, plasma levels of the proinflammatory chitenase‐like protein, YKL‐40, were influenced by environmental as well as genetic factors and predicted incident thromboembolic stroke, but not MI, a differential effect consistent with limited previous data.

The chitinase-like protein YKL-40 is not a useful biomarker for severe persistent asthma in children

BACKGROUND

The chitinase-like protein YKL-40 is thought to play a role in inflammation and tissue remodeling. In adults with severe asthma, YKL-40 is expressed in the airway and YKL-40 levels are elevated in the serum.

OBJECTIVE

To compare YKL-40 levels in children with severe persistent asthma with those in adults with severe persistent asthma and to determine whether YKL-40 levels correlate with increasing asthma severity in childhood asthma.

METHODS

In this prospective, cross-sectional study, 23 adults and 19 children with severe persistent asthma, 23 children with moderate persistent asthma, and 19 children with mild persistent asthma were enrolled. The following data were collected on each patient: spirometry, exhaled nitric oxide, percutaneous skin testing results to aeroallergens, peripheral eosinophils, serum IgE levels, and serum YKL-40 levels.

RESULTS

Compared with adults, children with severe persistent asthma had significantly lower YKL-40 levels, higher values for forced vital capacity and forced expiration volume in 1 second, higher serum IgE levels, and higher exhaled nitric oxide levels. YKL-40 levels did not correlate with increasing asthma severity in the pediatric cohort.

CONCLUSION

Severe persistent asthma in childhood is not associated with elevated YKL-40 levels, unlike in adults with severe persistent asthma. YKL-40 is not a useful biomarker for asthma severity in childhood asthma.

Chitinase 3-like 1 suppresses injury and promotes fibroproliferative responses in Mammalian lung fibrosis

Epithelial injury, alternative macrophage accumulation, and fibroproliferation coexist in the lungs of patients with idiopathic pulmonary fibrosis (IPF). Chitinase 3-like 1 (CHI3L1) is a prototypic chitinase-like protein that has been retained over species and evolutionary time. However, the regulation of CHI3L1 in IPF and its ability to regulate injury and/or fibroproliferative repair have not been fully defined. We demonstrated that CHI3L1 levels were elevated in patients with IPF. High levels of CHI3L1 are associated with progression--as defined by lung transplantation or death--and with scavenger receptor-expressing circulating monocytes in an ambulatory IPF population. In preterminal acute exacerbations of IPF, CHI3L1 levels were reduced and associated with increased levels of apoptosis. We also demonstrated that in bleomycin-treated mice, CHI3L1 expression was acutely and transiently decreased during the injury phase and returned toward and eventually exceeded baseline levels during the fibrotic phase. In this model, CHI3L1 played a protective role in injury by ameliorating inflammation and cell death, and a profibrotic role in the repair phase by augmenting alternative macrophage activation, fibroblast proliferation, and matrix deposition. Using three-dimensional culture system of a human fibroblast cell line, we found that CHI3L1 is sufficient to induce low grade myofibroblast transformation. In combination, these studies demonstrate that CHI3L1 is stimulated in IPF, where it represents an attempt to diminish injury and induce repair. They also demonstrate that high levels of CHI3L1 are associated with disease progression in ambulatory patients and that a failure of the CHI3L1 antiapoptotic response might contribute to preterminal disease exacerbations.

Serum YKL-40 levels and chitotriosidase activity in patients with beta-thalassemia major

BACKGROUND

YKL-40 association with human disease has been the object of many years of investigation. β-thalassemia patients are affected by hepatic siderosis, which determines a fibrotic process and tissue remodelling. Chitotriosidase has been found to be increased in thalassemic patients returning to normal in patients submitted to bone marrow transplantation. YKL-40 is associated with macrophage activation in liver and in other tissues. The aim of the study was to analyse the level of serum YKL-40 and plasma chitotriosidase activity of patients with beta-thalassemia to assess whether their expression correlates with liver disease and degree of liver siderosis.

METHODS

Expression of YKL-40 and chitotriosidase as a marker of inflammation in 69 thalassemic patients were evaluated. We sought to investigate whether these two chitinases could be considered as a significant biomarker to evaluate therapy effectiveness.

RESULTS

Surprisingly we found normal value of YKL-40. We, also, analysed chitotriosidase activity in the same patients that was slightly increased as a consequence of macrophage activation.

CONCLUSIONS

These data would suggest a good treatment for these patients.

Impact of endobronchial allergen provocation on macrophage phenotype in asthmatics

Background

The role of M2 polarized macrophages (MΦ) during the allergic airway inflammation has been discussed in various animal models. However, their presence and relevance during the chronic and acute phase of allergic airway inflammation in humans has not been fully elucidated so far. In the present study we phenotypically characterized macrophages with regard to M2 polarization in mice, a human in vitro and a human ex vivo model with primary lung cells after endobronchial provocation.

Results

Macrophages remained polarized beyond clearance of the acute allergic airway inflammation in mice. Alveolar macrophages of asthmatics revealed increased mRNA expression of CCL13, CCL17 and CLEC10A in response to allergen challenge as well as increased surface expression of CD86. Further, mRNA expression of CCL13, CCL17, and CLEC10A was increased in asthmatics at baseline compared to healthy subjects. The mRNA expression of CCL17 and CLEC10A correlated significantly with the degree of eosinophilia (each P < .01). Furthermore, macrophages from asthmatics released significant amounts of CCL17 protein in vitro which was also found increased in BAL fluid after allergen provocation.

Conclusions

This study supports previous findings of M2 macrophage polarization in asthmatic subjects during the acute course of the allergic inflammation and provides evidence for their contribution to the Th2 inflammation.

Increased expression of chitinase 3-like 1 in aorta of patients with atherosclerosis and suppression of atherosclerosis in apolipoprotein E-knockout mice by chitinase 3-like 1 gene silencing

INTRODUCTION

The purpose of this study was to investigate the changes of chitinase 3-like 1 (CHI3L1) in the aorta of patients with coronary atherosclerosis and to determine whether inhibition of CHI3L1 by lentivirus-mediated RNA interference could stabilize atherosclerotic plaques in apolipoprotein E-knockout (ApoE(-/-)) mice.

METHODS

We collected discarded aortic specimens from patients undergoing coronary artery bypass graft surgery and renal arterial tissues from kidney donors. A lentivirus carrying small interfering RNA targeting the expression of CHI3L1 was constructed. Fifty ApoE(-/-) mice were divided into control group and CHI3L1 gene silenced group. A constrictive collar was placed around carotid artery to induce plaques formation. Then lentivirus was transfected into carotid plaques.

RESULTS

We found that CHI3L1 was overexpressed in aorta of patients with atherosclerosis and its expression was correlated with the atherosclerotic risk factors. After lentivirus transduction, mRNA and protein expression of CHI3L1 were attenuated in carotid plaques, leading to reduced plaque content of lipids and macrophages, and increased plaque content of collagen and smooth muscle cells. Moreover, CHI3L1 gene silencing downregulated the expression of local proinflammatory mediators.

CONCLUSIONS

CHI3L1 is overexpressed in aorta from patients with atherosclerosis and the lentivirus-mediated CHI3L1 gene silencing could represent a new strategy to inhibit plaques progression.

Management of severe asthma in childhood--state of the art and novel perspectives

The majority of children with asthma have mild or moderate disease and can obtain adequate control of symptoms through avoidance of triggering factors and/or with the help of medications. There is still a group of children with severe asthma in whom symptom control is poor depending either on identifiable aggravating factors or on true therapy resistance. These children have a poor quality of life and are limited by the severity of their disease. There is a need for a staged approach to the assessment and treatment of this small but vulnerable and resource-consuming group. The current review will provide an overview of a possible standardized approach to characterize this heterogeneous group of severely sick children including some newly developed ways of assessing asthma severity and potentialities of new asthma therapies. Furthermore, the umbrella term 'problematic severe asthma' is described. The term encompasses children whose severe asthma is due to identifiable exacerbating factors, as well as children who are resistant to any conventional therapeutic approach. Characteristics of these two groups of children are described, as are possible biomarkers and current and emerging diagnostic tools for allergy evaluation. Some recent advances and future possibilities for treatment of severe asthma are also presented in this review.

Improvement in asthma control and inflammation in children undergoing adenotonsillectomy

BACKGROUND

Observational studies suggest that asthma control improves after adenotonsillectomy, but longitudinal studies that correlate the effect of the procedure on the levels of biomarkers associated with airway inflammation are limited.

METHODS

We conducted a longitudinal, observational study on pediatric patients, both with and without asthma, undergoing adenotonsillectomy. Asthma control test (ACT) scores and chitinase activity in the circulation were measured at time of surgery and at 6-mo follow-up.

RESULTS

Sixty-six children with asthma and 64 control subjects were enrolled. Mean ACT scores improved by three points (P < 0.001) after 6 mo. 85% of children with poorly controlled asthma demonstrated an increase in ACT score of at least three points or a decrease in emergency department/urgent care visits, oral corticosteroid courses, or rescue short acting bronchodilator usage. Chitinase activity decreased significantly in asthmatics who improved (P < 0.01). Higher chitinase activity levels at baseline were associated with improved asthma control following surgery (P < 0.01).

CONCLUSION

In children with high preoperative circulating chitinase activity levels, asthma control and healthcare utilization were significantly improved after adenotonsillecotmy. Chitinase activity decreased after surgery in children with improved control. This suggests that adenotonsillectomy modulates chitinase activity, affecting airway inflammation and improving airway disease.

Potential association between TLR4 and chitinase 3-like 1 (CHI3L1/YKL-40) signaling on colonic epithelial cells in inflammatory bowel disease and colitis-associated cancer

Inflammatory bowel disease (IBD) is a group of inflammatory disorders in the small and large intestines. Several studies have proved that persistent and disregulated host/microbial interactions are required for the development of IBD. It is well known that chronic IBD is strongly associated with an increased risk of developing colorectal cancer by 0.5-1% annually, 8-10 years after the initial diagnosis. To detect the tiny dysplasia or early stage of cancer in chronic IBD patients, a tremendous amount of effort is currently directed for improving colonoscopic technology and noninvasive serological marker development. However, there is only a limited amount of data available to understand the exact mechanism of how long term chronic colitis is connected to the development of colorectal tumors. Recently, our group has identified significantly increased expression of chitinase 3-like 1 (CHI3L1) molecule in non-dysplastic mucosa from patients with IBD and remote dysplasia/cancer, compared to patients with IBD without dysplasia or healthy controls. CHI3L1 seems to contribute to the proliferation, migration, and neoplastic progression of colonic epithelial cells (CECs) under inflammatory conditions. Furthermore, the TLR4-mediated intracellular signaling cascade is likely to interact with CHI3L1 signaling in CECs. In this review article, we have concisely summarized the cellular and molecular mechanisms underlining the development of IBD and colitis-associated cancer, with particular focus on the TLR4- and CHI3L1-signaling pathways in CECs.

Asthma exacerbations: predisposing factors and prediction rules

PURPOSE OF REVIEW

Asthma is a multifaceted disease that is associated with decreased lung function, multiple symptoms, varying levels of asthma control, and risk of acute exacerbations. The ability to predict the risk of developing acute exacerbations may improve the management of asthmatics and facilitate identification of these patients for interventional studies.

RECENT FINDINGS

Factors that are associated with different manifestations of asthma differ. Biomarkers that are correlated with airways hyper-responsiveness do not necessarily correlate with risk of future exacerbations. Genetic factors that segregate with exacerbation risk are beginning to emerge. Outcome measures that demonstrate predictive validity have been developed and may facilitate patient management and provide novel clinically meaningful endpoints in clinical trials.

SUMMARY

This review will emphasize underlying factors associated with asthma exacerbations and clinical prediction rules that correlate with the risk of developing severe exacerbations of asthma.

Asthma across the ages: knowledge gaps in childhood asthma

The Eunice Kennedy Shriver National Institute of Child Health and Human Development convened an Asthma Group in response to the Best Pharmaceuticals for Children Act. The overall goal of the Best Pharmaceuticals for Children Act Program is to improve pediatric therapeutics through preclinical and clinical drug trials that lead to drug-labeling changes. Although significant advances have been made in the understanding and management of asthma in adults with appropriately labeled medications, less information is available on the management of asthma in children. Indeed, many medications are inadequately labeled for use in children. In general, the younger the child, the less information there is available to guide clinicians. Because asthma often begins in early childhood, it is incumbent on us to continue to address the primary questions raised in this review and carefully evaluate the medications used to manage asthma in children. Meanwhile, continued efforts should be made in defining effective strategies that reduce the risk of exacerbations. If the areas of defined need are addressed in the coming years, namely prevention of exacerbations and progression of disease, as well as primary intervention, we will see continuing reduction in asthma mortality and morbidity along with improved quality of life for children with asthma.

YKL-40 is a Protective Biomarker for Fatty Liver in World Trade Center Particulate Matter-Exposed Firefighters

Background

Serum biomarkers of metabolic syndrome predict abnormal lung function in World Trade Center particulate matter (WTC-PM)-exposed Fire Department of New York (FDNY) rescue workers. In animal models, exposure to ambient PM induces non-alcoholic fatty liver disease (NAFLD), a well-known comorbidity of metabolic syndrome. YKL-40 is an inflammatory biomarker for both liver and lung disease. We tested if YKL-40 is a biomarker for NAFLD in this dust-exposed cohort.

Methods

Using a nested case-control design, we studied 131 FDNY personnel who had Computer Tomography performed within 5 years post 9/11. NAFLD was defined by a liver/spleen attenuation ratio of ≤1. Serum biomarkers, lipid panel and liver function were measured in serum that had been drawn within 6 months of September 11, 2001. YKL-40 and chitotriosidase were assayed by ELISA. We tested biomarker and NAFLD association using logistic regression adjusted for age, BMI, and post-911 lung function.

Results

NAFLD was present in 29/131 (22%) of the cohort. In a multivariable model increasing YKL-40 was protective while increasing triglyceride and alkaline phosphatase were risk factors for NAFLD.

Conclusions

Increased YKL-40 is a protective biomarker in non-alcoholic fatty liver disease. Further studies may reveal a link between PM-induced lung and liver diseases.

Plasma YKL-40 and all-cause mortality in patients with chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is hallmarked by inflammatory processes and a progressive decline of lung function. YKL-40 is a potential biomarker of inflammation and mortality in patients suffering from inflammatory lung disease, but its prognostic value in patients with COPD remains unknown. We investigated whether high plasma YKL-40 was associated with increased mortality in patients with moderate to very severe COPD.

METHODS

Four hundred and ninety-three patients with moderate to very severe COPD were followed prospectively for up to 10 years. Patients were divided into two groups according to plasma YKL-40: concentration higher than the 75th percentile for age-matched healthy subjects (i.e. high levels) and normal levels. Outcome was overall survival (OS) and was evaluated in uni- and multivariate proportional hazards Cox regression analyses and adjusted for factors affecting mortality.

RESULTS

Median plasma YKL-40 was increased in patients with COPD (81 ng/ml, p < 0.001) compared to healthy subjects (40 ng/ml). Patients with high plasma YKL-40 had a hazard ratio (HR) of 1.42 (95% CI: 1.15-1.75, p = 0.001) for all-cause mortality. Multivariate analysis showed that YKL-40 (HR 1.38; 95% CI: 1.11-1.72, p = 0.004), age (HR 1.05; 95% CI: 1.03-1.06, p < 0.0001), Severe COPD (HR 1.35; 95 CI: 1.03-1.76, p = 0.03) very severe COPD (HR 2.19; 95% CI: 1.60 - 2.99 < 0.0001), neutrophil granulocyte count (HR 1.05; 95% CI: 1.01-1.08, p = 0.01), and a smoking history of > 40 years (HR 1.38; 95% CI: 1.11-1.71, p = 0.003) were independent prognostic markers of OS.

CONCLUSION

High plasmaYKL-40 is associated with increased mortality in patients with moderate to very severe COPD, suggesting a role for YKL-40 as a potential biomarker of mortality in this patient group.

Exploring the role of CHI3L1 in "pre-metastatic" lungs of mammary tumor-bearing mice

Elevated levels of chitinase-3-like-1 (CHI3L1) are associated with poor prognosis, shorter recurrence-free intervals and low survival in breast cancer patients. Breast cancer often metastasizes to the lung. We hypothesized that molecules expressed in the “pre-metastatic” lung microenvironment could support the newly immigrant tumor cells by providing growth and angiogenic factors. Macrophages are known to play an important role in tumor growth by releasing pro-angiogenic molecules. Using mouse mammary tumor models, we have previously shown that during neoplastic progression both the mammary tumor cells and splenic macrophages from tumor-bearing mice express higher levels of CHI3L1 compared to normal control mice. However, the role of CHI3L1 in inducing angiogenesis by macrophages at the pulmonary microenvironment to support newly arriving breast cancer cells is not yet known. In this study, we determined the expression of CHI3L1 in bronchoalveolar lavage macrophages and interstitial macrophages in regulating angiogenesis that could support the growth of newly immigrant mammary tumor cells into the lung. Here we show that in vitro treatment of pulmonary macrophages with recombinant murine CHI3L1 resulted in enhanced expression of pro-angiogenic molecules including CCL2, CXCL2, and MMP-9. We and others have previously shown that inhibition of CHI3L1 decreases the production of angiogenic molecules. In this study, we explored if in vivo administration of chitin microparticles has an effect on the expression of CHI3L1 and pro-angiogenic molecules in the lungs of mammary tumor-bearing mice. We show that treatment with chitin microparticles decreases the expression of CHI3L1 and pro-angiogenic molecules in the “metastatic” lung. These studies suggest that targeting CHI3L1 may serve as a potential therapeutic agent to inhibit angiogenesis and thus possibly tumor growth and metastasis.

The influence of chitin on the immune response to the house dust mite allergen Blo T 12

BACKGROUND

Information about the biological properties of Blomia tropicalis allergens is scarce. It is predicted that Blo t 12, an allergen with two described isoforms, contains a chitin-binding domain, similar to that found in peritrophins. Th2 adjuvant properties have been described for chitin. Therefore, it is feasible that binding to this carbohydrate influences its allergenicity. We aimed to evaluate the chitin-binding activity of Blo t 12 isoallergens and its effect on airway inflammation and antibody responses in a murine model of allergen sensitization.

METHODS

Chitin-binding assays were conducted with the recombinant isoallergens Blo t 12.0101 and Blo t 12.0102. BALB/c mice were sensitized via i.p. with any of the two isoforms (alone, with chitin or alum) and then challenged intranasally. Methacholine-induced bronchial hyperreactivity was tested by whole-body plethysmography and lung sections were stained with hematoxylin and eosin and periodic-acid Schiff. Total IgE and allergen-specific IgE, IgG1 and IgG2 levels were measured by ELISA.

RESULTS

The two isoforms bound chitin, but Blo t 12.0101 showed a stronger binding capacity. Both isoforms induced total and allergen-specific IgE, airway hyperreactivity, bronchial inflammation and mucus secretion without any adjuvant; however, when administered with chitin, Blo t 12.0101 induced higher total IgE levels. The IgG1/IgG2a ratio was significantly higher in mice immunized with Blo t 12.0101 than those immunized with Blo t 12.0102. As peritrophins, Blo t 12 was detected in mite feces.

CONCLUSIONS

Blo t 12 isoforms are chitin-binding proteins that induce airway inflammation and bronchial hyperreactivity. However, for Blo t 12.0101, chitin reinforces its effects on total IgE production.

Serum based diagnosis of asthma using Raman spectroscopy: an early phase pilot study

The currently prescribed tests for asthma diagnosis require compulsory patient compliance, and are usually not sensitive to mild asthma. Development of an objective test using minimally invasive samples for diagnosing and monitoring of the response of asthma may help better management of the disease. Raman spectroscopy (RS) has previously shown potential in several biomedical applications, including pharmacology and forensics. In this study, we have explored the feasibility of detecting asthma and determining treatment response in asthma patients, through RS of serum. Serum samples from 44 asthma subjects of different grades (mild, moderate, treated severe and untreated severe) and from 15 reference subjects were subjected to Raman spectroscopic analysis and YKL-40 measurements. The force expiratory volume in 1 second (FEV1) values were used as gold standard and the serum YKL-40 levels were used as an additional parameter for diagnosing the different grades of asthma. For spectral acquisition, serum was placed on a calcium fluoride (CaF2) window and spectra were recorded using Raman microprobe. Mean and difference spectra comparisons indicated significant differences between asthma and reference spectra. Differences like changes in protein structure, increase in DNA specific bands and increased glycosaminoglycans-like features were more prominent with increase in asthma severity. Multivariate tools using Principal-component-analysis (PCA) and Principal-component based-linear-discriminant analysis (PC-LDA) followed by Leave-one-out-cross-validation (LOOCV), were employed for data analyses. PCA and PC-LDA results indicate separation of all asthma groups from the reference group, with minor overlap (19.4%) between reference and mild groups. No overlap was observed between the treated severe and untreated severe groups, indicating that patient response to treatment could be determined. Overall promising results were obtained, and a large scale validation study on random subjects is warranted before the routine clinical usage of this technique.

Ovalbumin enhances YKL-40, IL-5, GM-CSF, and eotaxin expression simultaneously in primarily cultured mouse tracheal epithelial cells

Epithelial inflammation and eosinophil infiltration are crucial for the pathogenesis of asthma. Many inflammatory mediators, such as YKL-40, interleukin -5 (IL-5), granulocyte-macrophage colony-stimulating factor (GM-CSF), and eotaxin, are important for the development of allergic airway inflammation. This study is aimed at investigating the impact of treatment with ovalbumin (OVA) on the levels of those inflammatory mediators in primarily cultured mouse tracheal epithelial cells. Mouse tracheal epithelial cells were isolated and identified by immunofluorescent staining; the isolated mouse tracheal epithelial cells expressed cytokeratins. Treatment with OVA for 24 or 48 h significantly increased the relative levels of YKL-40, IL-5, GM-CSF, and eotaxin mRNA transcripts and YKL-40, IL-5, GM-CSF, and eotaxin proteins secreted in the supernatants of cultured cells, as compared with that in the untreated control cells (P < 0.01, P < 0.05, respectively). The levels of YKL-40 expression were correlated positively with the levels of IL-5, GM-CSF, and eotaxin expression in the OVA-treated cells. These data indicated that treatment with OVA simultaneously enhanced YKL-40, IL-5, GM-CSF, and eotaxin expression in the cultured mouse tracheal epithelial cells in vitro. These inflammatory mediators may synergistically contribute to the pathogenesis of allergic inflammation, and this study may help to understand the role of YKL-40 in the pathogenesis of asthma.

Serum biomarkers in elderly asthma

OBJECTIVE

Asthma is usually misdiagnosed and under-treated in the elderly population, resulting in complications and increased severity to the patient. In this review, we describe some of the most important serum markers of asthma studied so far, reporting their outcomes and possible prediction of asthma in the elderly population.

METHODS

The PubMed electronic database was used to search for promising serum biomarkers of asthma studied in original articles published in peer-reviewed journals from 2000 to January 2013.

RESULTS

A total of 13 relevant serum biomarkers were selected, including IgE, CRP, high sensitive CRP, IL-6, IL-8, IL-17, TNF-α, neopterin, serum amyloid A, eosinophil cationic protein, leukolysin, YKL-40 and soluble CD86.

CONCLUSIONS

Although the major focus of treatment and research has been on allergic asthma, several forms of the disease are recognized, such as neutrophilic asthma, which is characteristic of older patients. Different phenotypes imply different treatments and so it becomes important to correctly determine which type of asthma the patient is suffering from. Serum markers capable of supporting a diagnosis of asthma are needed in order to counter mistreatment and misdiagnosis with other obstructive airways disease (OAD) in elderly patients. As convenient as serum markers may seem to be, a marker capable of accurately identifying asthma with sufficient specificity is yet to be found.

The role of macrophages in obstructive airways disease: chronic obstructive pulmonary disease and asthma

Macrophages are a major cellular component of the innate immune system, and play an important role in the recognition of microbes, particulates, and immunogens and to the regulation of inflammatory responses. In the lung, macrophages react with soluble proteins that bind microbial products in order to remove pathogens and particles and to maintain the sterility of the airway tract. Chronic obstructive pulmonary disease and asthma are both obstructive airway diseases that involve chronic inflammation of the respiratory tract which contributes to disease progression. In the case of COPD, there is increasing evidence that lung macrophages orchestrate inflammation through the release of chemokines that attract neutrophils, monocytes and T cells and the release of several proteases. On the other hand, in asthma, it seems that alveolar macrophages are inappropriately activated and are implicated in the development and progression of the disease. In this review we summarize the current basic and clinical research studies which highlight the role of macrophages in asthma and COPD.

Attenuation of allergic airway inflammation in a murine model of asthma by Licochalcone A

CONTEXT

Licochalcone A (Lico A) is a major and biogenetically characteristic chalcone isolated from the root of Xinjiang liquorice, Glycyrrhiza inflata.

OBJECTIVE

We focused on investigating whether Lico A possesses distinct anti-inflammatory activity on a non-infectious mouse model of asthma, and we aimed to elucidate its involvement with the mitogen-activated protein kinases pathway.

METHODS

BALB/c mice that were sensitized and challenged to ovalbumin (OVA) were treated with Lico A (50 mg/kg) 1 h before they were challenged with OVA.

RESULTS

Our study demonstrated that Lico A may effectively inhibit the increase in T-helper type 2 cytokines, such as interleukin (IL)-4, IL-5 and IL-13 in bronchoalveolar lavage fluid, and reduced serum levels of OVA-specific IgE and IgG. Furthermore, Lico A substantially inhibited OVA-induced eosinophilia in lung tissue and mucus hyper-secretion by goblet cells in the airway. Meanwhile, pretreatment with Lico A resulted in a significant reduction in mRNA expression of acidic mammalian chitinase, chitinase 3-like protein 4 (Ym2), E-selectin, Muc5ac, CCL11 and CCR3 in lung tissues and airway hyper-responsiveness to methacholine.

CONCLUSIONS

These findings suggest that Lico A may effectively delay the progression of airway inflammation and could be used as a therapy for patients with allergic airway inflammation.

The chitinase-like protein YKL-40 increases mucin5AC production in human bronchial epithelial cells

Mucus overproduction is an important feature in patients with chronic inflammatory airway diseases. However, the regulatory mechanisms that mediate excessive mucin production remain elusive. Recently, the level of YKL-40, a chitinase-like protein, has been found to be significantly increased in chronic inflammatory airway diseases and has been shown to be associated with the severity of these diseases. In this study, we sought to explore the effect of YKL-40 on mucin5AC (MUC5AC) production in chronic inflammatory airway diseases and the potential signaling pathways involved in this process. We found that elevated YKL-40 levels increased the mRNA and protein expression of MUC5AC in a dose- and time-dependent manner, in association with the phosphorylation of extracellular signal-regulated kinase (ERK) and nuclear factor κB (NF-κB), reflecting their activation. These responses were significantly suppressed by the knockdown of protease-activating receptor 2 (PAR2) with specific small interfering RNA or the inhibitors of ERK and NF-κB. YKL-40-induced MUC5AC overproduction was also effectively attenuated by the inhibitor of focal adhesion kinase (FAK). Taken together, these results imply that YKL-40 can stimulate excessive MUC5AC production through PAR2- and FAK-mediated mechanisms.