Plasma YKL-40 and NGAL are useful in distinguishing ACO from asthma and COPD

Neutrophil gelatinase-associated lipocalin as a potential biomarker for equine asthma

BACKGROUND

Studies in people have found neutrophil gelatinase-associated lipocalin (NGAL) concentrations are increased in asthma and can be used to distinguish between asthma subtypes. NGAL has not yet been investigated in equine asthma (EA).

OBJECTIVES

To investigate the ability of NGAL concentrations in bronchoalveolar lavage (BAL) fluid and serum to distinguish between control horses, horses with mild-moderate EA (MEA) and horses with severe EA (SEA).

STUDY DESIGN

Retrospective cross-sectional study.

METHODS

Details of endoscopic examination including tracheal mucus score (TMS, scale 0-5) and BAL cytology performed on 227 horses were extracted from records and NGAL concentrations were measured on stored serum and BAL fluid samples. The horses were divided into groups (control group n = 73, MEA n = 98, SEA n = 56) based on clinical signs and BAL cytology results. Differences between groups were evaluated with the Mann-Whitney test and correlation between BAL NGAL, serum NGAL, and BAL cytology were evaluated using Spearman's correlation.

RESULTS

BAL NGAL concentrations were higher in EA than in control horses (median: 25.6 and 13.3 μg/L, respectively, p < 0.001). Concentrations of NGAL in BAL differed between groups, with higher concentrations in MEA than in control horses (median: 18.5 and 13.3 μg/L, respectively, p < 0.001), and higher concentrations in SEA than in MEA horses (median: 54.1 and 18.5 μg/L, respectively, p < 0.001). BAL NGAL concentration differed between horses with TMS ≤2 an >2 (median 15.6 and 21.1 μg/L, respectively, p = 0.004). No differences were found in serum NGAL concentration between any of the groups.

MAIN LIMITATION

Only 66 of the 227 (29%) horses had haematology and serum NGAL measured.

CONCLUSION

BAL NGAL concentration differed between control and EA and reflected severity of disease. These results justify further research into the potential of NGAL as a biomarker of EA.

Serum MMP3 and IL1-RA levels may be useful biomarkers for detecting asthma and chronic obstructive pulmonary disease overlap in patients with asthma

Background

Asthma and chronic obstructive pulmonary disease (COPD) overlap (ACO) is characterized by concurrent features of asthma and COPD. Since disease pathogenesis, severities, and treatments differ between asthma and ACO, it is important to differentiate them.

Objective

To clarify and compare the characteristics of ACO and asthma and identify the serum biomarkers for differentiating them, especially in older patients.

Methods

This study used the data of 639 participants from the nationwide cohort study, the NHOM-Asthma study, an asthma registry in Japan, with complete information on smoking history, respiratory function, and serum biomarkers. ACO was defined as the self-reported comorbidity of COPD or emphysema, or with obstructive pulmonary function and smoking history (pack-years≥10). The clinical characteristics of patients with ACO and asthma without COPD were compared. The serum biomarkers for differentiation were examined using receiver operating characteristic curves and multivariable analysis. The associations between the biomarkers and age were also analyzed.

Results

Of the 639 asthma patients, 125 (19.6%) were diagnosed with ACO; these patients were older and male-dominant and had a higher prevalence of comorbidities such as hypertension, diabetes, and stroke. Among the serum biomarkers that were significantly different between ACO and asthma without COPD, the YKL-40/CHI3L1, MMP3, and IL-1RA levels showed a high area under the curve for discriminating ACO. Only the MMP3 and IL-1RA levels were significantly higher among ACO patients, regardless of age and sex; the YKL-40/CHI3L1 levels were not different due to the effect of age.

Conclusion

MMP3 and IL-1RA may be useful serum biomarkers for distinguishing ACO from asthma.

Airway inflammatory changes in the lungs of patients with asthma-COPD overlap (ACO): a bronchoscopy endobronchial biopsy study

BACKGROUND

Although asthma and chronic obstructive pulmonary disease (COPD) are two distinct chronic airway inflammatory diseases, they often co-exist in a patient and the condition is referred to as asthma-COPD overlap (ACO). Lack of evidence regarding the inflammatory cells in ACO airways has led to their poor prognosis and treatment. The objective of this endobronchial biopsy (EBB) study was to enumerate inflammatory cellular changes in the airway wall of ACO compared with asthma, COPD current smokers (CS) and ex-smokers (ES), normal lung function smokers (NLFS), and non-smoker controls (HC).

METHODS

EBB tissues from 74 patients were immunohistochemically stained for macrophages, mast cells, eosinophils, neutrophils, CD8+ T-cells and CD4+ T-cells. The microscopic images of stained tissues were evaluated in the epithelium, reticular basement membrane (RBM) cells/mm RBM length, and lamina propria (LP) cells/mm2 up to a depth of 120 µM using the image analysis software Image-Pro Plus 7.0. The observer was blinded to the images and disease diagnosis. Statistical analysis was performed using GraphPad Prism v9.

RESULTS

The tissue macrophages in ACO were substantially higher in the epithelium and RBM than in HC (P < 0.001 for both), COPD-ES (P < 0.001 for both), and -CS (P < 0.05 and < 0.0001, respectively). The ACO LP macrophages were significantly higher in number than COPD-CS (P < 0.05). The mast cell numbers in ACO were lower than in NLFS (P < 0.05) in the epithelium, lower than COPD (P < 0.05) and NLFS (P < 0.001) in RBM; and lower than  HC (P < 0.05) in LP. We noted lower eosinophils in ACO LP than HC (P < 0.05) and the lowest neutrophils in both ACO and asthma. Furthermore, CD8+ T-cell numbers increased in the ACO RBM than HC (P < 0.05), COPD-ES (P < 0.05), and NLFS (P < 0.01); however, they were similar in number in epithelium and LP across groups. CD4+ T-cells remained lower in number across all regions and groups.

CONCLUSION

These results suggest that the ACO airway tissue inflammatory cellular profile differed from the contributing diseases of asthma and COPD with a predominance of macrophages.

YKL-40 as a possible marker of neutrophilic asthma

Asthma is a heterogeneous chronic disorder of the airways, with inflammation and bronchial hyperresponsiveness as its major underlying phenomena. Asthmatics vary in terms of inflammation pattern, concomitant pathologies, and factors aggravating the course of the disease. As a result, there is a need for sensitive and specific biomarkers that could facilitate diagnosing asthma as well as phenotyping in everyday practice. Chitinases and chitinase-like proteins (CLPs) seem promising in this field. Chitinases are evolutionarily conserved hydrolases that degrade chitin. In contrast, CLPs bind chitin but do not have degrading activity. Mammalian chitinases and CLPs are produced by neutrophils, monocytes, and macrophages in response to parasitic or fungal infections. Recently, several questions have been raised about their role in chronic airway inflammation. Several studies demonstrated that overexpression of CLP YKL-40 was associated with asthma. Moreover, it correlated with exacerbation rate, therapy resistance, poor control of symptoms, and, inversely, with FEV₁. YKL-40 facilitated allergen sensitization and IgE production. Its concentration was elevated in bronchoalveolar lavage fluid after an allergen challenge. It was also found to promote the proliferation of bronchial smooth muscle cells and correlate with subepithelial membrane thickness. Thus, it may be involved in bronchial remodeling. Associations between YKL-40 and particular asthma phenotypes remain unclear. Some studies showed that YKL-40 correlates with blood eosinophilia and FeNO, suggesting a role in T2-high inflammation. Quite the opposite, cluster analyses revealed the highest upregulation in severe neutrophilic asthma and obesity-associated asthma. The main limitation in the practical application of YKL-40 as a biomarker is its low specificity. High serum levels of YKL-40 were also found in COPD and several malignancies, in addition to infectious and autoimmune diseases. To conclude, the level of YKL-40 correlates with asthma and some clinical features in the whole asthmatic population. The highest levels are found in neutrophilic and obesity-related phenotypes. However, due to its low specificity, the practical application of YKL-40 remains uncertain but could be useful in phenotyping, especially when combined with other biomarkers.

Clinical Indicators for Asthma-COPD Overlap: A Systematic Review and Meta-Analysis

Background

Some clinical indicators have been reported to be useful in differentiating asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO) from pure asthma/COPD, but the results were inconsistent. This study aims to evaluate the diagnostic value of these indicators for ACO.

Methods

Databases of PubMed, EMBASE, Ovid and Web of Science were retrieved. Pooled standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated in random-effects models.

Results

48 eligible studies were included. The pooled results indicated, compared with pure asthma, ACO patients had lower levels of forced expiratory volume in the first second (FEV₁)% predicted (pred) (SMD=−1.09, 95% CI −1.3 to −0.87), diffusion lung capacity for carbon monoxide (DLCO)% pred (SMD=−0.83, 95% CI −1.24 to −0.42), fractional exhaled nitric oxide (FeNO) (SMD=−0.23, 95% CI −0.36 to −0.11), and higher levels of induced sputum neutrophil (SMD = 0.51, 95% CI 0.21 to 0.81), circulating YKL-40 (SMD = 0.96, 95% CI 0.27 to 1.64). However, relative to COPD alone, ACO patients had higher levels of FEV₁% pred (SMD = 0.15, 95% CI 0.05 to 0.26), DLCO% pred (SMD = 0.38, 95% CI 0.16 to 0.6), FeNO (SMD = 0.59, 95% CI 0.40 to 0.78), serum total immunoglobulin (Ig)E (SMD = 0.42, 95% CI 0.1 to 0.75), blood eosinophil (SMD = 0.44, 95% CI 0.29 to 0.59), induced sputum eosinophil (SMD = 0.62, 95% CI 0.42 to 0.83), and lower levels of induced sputum neutrophil (SMD=−0.48, 95% CI −0.7 to −0.27), circulating YKL-40 (SMD=−1.09, 95% CI −1.92 to −0.26).

Conclusion

Compared with pure asthma/COPD, ACO patients have different levels of FEV₁% pred, DLCO% pred, FeNO, serum total IgE, blood eosinophil, induced sputum eosinophil/neutrophil, and circulating YKL-40, which could be helpful to establish a clinical diagnosis of ACO.

Neutrophil gelatinase-associated lipocalin as a prognostic biomarker of severe acute respiratory distress syndrome

Neutrophil gelatinase-associated lipocalin (NGAL) is produced in the bronchial and alveolar cells of inflamed lungs and is regarded as a potential prognostic biomarker in various respiratory diseases. However, there are no studies on patients with acute respiratory distress syndrome (ARDS). NGAL levels in serum and bronchoalveolar lavage (BAL) were measured at baseline and on day 7 in 110 patients with ARDS. Baseline NGAL levels were significantly higher in ARDS patients than in healthy controls (serum 25 [14.5–41] vs. 214 [114.5–250.3] ng/mL; BAL 90 [65–115] vs. 211 [124–244] ng/mL). In ARDS, baseline NGAL levels in serum and BAL were significantly higher in non-survivors than in survivors (p < 0.001 and p = 0.021, respectively). Baseline NGAL levels showed a fair predictive power for intensive care unit (ICU) mortality (serum area under the curve (AUC) 0.747, p < 0.001; BAL AUC 0.768, p < 0.001). In a multivariate Cox regression analysis, the baseline serum NGAL level (> 240 ng/mL) was significantly associated with ICU mortality (hazard ratio [HR] 5.39, 95% confidence interval [CI] 2.67–10.85, p < 0.001). In particular, day 7 NGAL was significantly correlated with day 7 driving pressure (serum r = 0.388, BAL r = 0.702), and 28 ventilator-free days (serum r = − 0.298, BAL r = − 0.297). Baseline NGAL has good prognostic value for ICU mortality in patients with ARDS. NGAL can be a biomarker for ventilator requirement, as it may be indicative of potential alveolar epithelial injury.

Difference of Serum Cytokine Profile in Allergic Asthma Patients According to Disease Severity

Purpose

Allergic asthma is a heterogeneous disease with complex underlying mechanisms. Cytokines are key mediators in immune system and potential indicators of disease status. The aim of this study is to compare the difference of serum cytokine profile in allergic asthma patients with different disease severity and explore candidate biomarkers for disease monitoring and targeting therapeutic agents.

Patients and Methods

A total of 40 allergic asthmatics (mild, n=22; moderate-to-severe, n=18) were included in this study. Serum samples, lung function and exhaled nitric oxide data were collected from each subject. A Meso Scale Discovery (MSD) electrochemiluminescence platform was applied to access serum levels of 33 cytokines. Serum cytokine profile was compared between mild and moderate-to-severe allergic asthmatics, and the correlation between serum cytokine levels, lung function and exhaled nitric oxide were analyzed.

Results

Moderate-to-severe allergic asthmatics displayed higher levels of eotaxin-1, eotaxin-2, MCP-1, MCP-2, MCP-3, YKL-40 and lower IL-23, IL-31 and TRAIL in serum in comparison with mild allergic asthmatics. Serum YKL-40, eotaxin-1 and MCP-1 had the best ability to discriminate mild and moderate-to-severe allergic asthmatics, with an AUC of 0.833, 0.811 and 0.760. Serum IP-10 was positively correlated with FeNO levels, while FnNO displayed a strong positive correlation with serum IL-25.

Conclusion

Compared with mild allergic asthmatics, significant increase in serum eotaxin-1, eotaxin-2, MCP-1, MCP-2, MCP-3, YKL-40 and decrease in serum IL-23, IL-31 and TRAIL was noted in moderate-to-severe allergic asthmatics. YKL-40, eotaxin-1 and MCP-1 might be candidate biomarkers in reflecting severity in allergic asthma patients.

Proteomics analysis reveals suppression of IL-17 signaling pathways contributed to the therapeutic effects of Jia-Wei Bu-Shen-Yi-Qi formula in a murine asthma model

BACKGROUND

Jia-Wei Bu-Shen-Yi-Qi formula (JWBSYQF), a Chinese herbal formula, is a commonly used prescription for treating asthma patients. However, the targeted proteins associated with JWBSYQF treatment remain unknown.

PURPOSE

Present study aims to evaluate the therapeutic efficacy of JWBSYQF and identify the targeted proteins in addition to functional pathways.

STUDY DESIGN

The ovalbumin (OVA)-induced murine asthma model was established to explore the therapeutic effect of JWBSYQF treatment. Proteomic profiling and quantifications were performed using data-independent acquisition (DIA) methods. Differentially expressed proteins (DEPs) were validated via western blot (WB) and immunohistochemistry (IHC).

METHODS

A murine asthma model was made by OVA sensitization and challenge, and JWBSYQF (2.25, 4.50, 9,00 g/kg body weight) or dexamethasone (1 mg/ kg body weight) were administered orally. Airway hyperresponsiveness (AHR) to methacholine (Mch), inflammatory cell counts and classification in bronchoalveolar lavage fluid (BALF), lung histopathology, and cytokine levels were measured. Furthermore, DIA proteomic analyses were performed to explore the DEPs targeted by JWBSYQF and were further validated by WB and IHC.

RESULTS

Our results exhibited that JWBSYQF attenuated AHR which was mirrored by decreased airway resistance and increased lung compliance. In addition, JWBSYQF-treated mice showed reduced inflammatory score, mucus hypersecretion, as well as reduced the number of BALF leukocytes along with decreased content of BALF Th2 inflammatory cytokines (IL-4, IL-5, IL-13) and serum IgE. Proteomics analysis identified 704 DEPs between the asthmatic mice and control group (MOD vs CON), and 120 DEPs between the JWBSYQF-treatment and the asthmatic mice (JWB-M vs MOD). A total of 33 overlapped DEPs were identified among the three groups. Pathway enrichment analysis showed that DEPs were significantly enriched in IL-17 signaling pathway, in which DEPs, Lcn2, TGF-β1, Gngt2, and Ppp2r5e were common DEPs between three experimental groups. WB and IHC results further validated expressional levels and tendency of these proteins. Our results also showed that JWBSYQF affects mitogen activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) signaling pathways, that are activated by IL-17 signaling.

CONCLUSION

The present study suggested that JWBSYQF could attenuate AHR and airway inflammation in OVA-induced asthmatic mice. In addition, proteomics analysis revealed that suppression of IL-17 signaling pathways contributes to the therapeutic effects of JWBSYQF.

Serum YKL-40 Levels Predict Endotypes and Associate with Postoperative Recurrence in Patients with Chronic Rhinosinusitis with Nasal Polyps

Background

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a global health concern with high heterogeneity and rate of postoperative recidivation. YKL-40 is a pivotal pro-inflammatory mediator to promote Th2 immune response which is involved in many inflammatory diseases. This study aimed to investigate the predictive value of serum YKL-40 in CRSwNP endotypes and postoperative recurrence.

Methods

We recruited 80 primary CRSwNP, 40 recurrent CRSwNP patients and 40 healthy controls (HCs) in this study, and the serum and tissue specimens were collected. The middle turbinate mucosa tissue collected from patients undergoing septoplasty was used as control. Serum YKL-40 concentrations were detected by enzyme-linked immunosorbent assay (ELISA), and tissue YKL-40 mRNA and protein levels were examined using quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC). The difference of YKL-40 expression was compared among different group. Multivariate analysis and receiver operating characteristic (ROC) curve were performed to evaluate the value of serum YKL-40 in discriminating eosinophilic CRSwNP (eCRSwNP) and predicting postoperative recurrence.

Results

The serum YKL-40 levels in CRSwNP patients were higher than HCs, especially in eCRSwNP patients (p < 0.05). The elevated YKL-40 levels positively correlated with blood eosinophil percentage, tissue eosinophil counts and percentages (p < 0.05). The serum YKL-40 levels in recurrent CRSwNP patients were markedly enhanced than primary CRSwNP patients (p < 0.05). The YKL-40 mRNA and protein levels were significantly elevated in CRSwNP patients compared to HCs, especially in eCRSwNP and recurrent CRSwNP group. Multivariate analysis and ROC curve exhibited that serum YKL-40 might be a promising indicator in distinguishing CRSwNP endotypes and predicting postoperative recurrence.

Conclusion

Our data suggested that YKL-40 might be unregulated in CRSwNP and associated with mucosal eosinophilia and recurrence. Serum YKL-40 appeared to a novel biomarker for predicting CRSwNP endotypes and postoperative recurrence of CRSwNP.

Association between YKL-40 and asthma: a systematic meta-analysis

PURPOSE

Many studies have shown that chitinase-3-like protein 1 (CHI3L1), also known as YKL-40, is associated with asthma. The purpose of this meta-analysis was to evaluate the role of serum YKL-40 in the diagnosis and differential diagnosis of asthma, severity grading, and determination of disease state.

METHODS

The PubMed, Ovid, and Cochrane databases were searched. A total of 17 articles involving 5696 subjects were included in this meta-analysis.

RESULTS

The results showed that the level of YKL-40 was significantly higher in asthmatic patients than in the normal group regardless of age and residential location, and increased with severity and acute exacerbation (p < 0.05). YKL-40 levels were significantly different between chronic obstructive pulmonary disease (COPD) and asthma, and also between asthma-COPD overlap syndrome (ACO) and asthma (p < 0.05).

CONCLUSION

YKL-40 may act as a potential serological marker for the diagnosis of asthma, assessment of severity, indicator of the disease state, and differential diagnosis of COPD, ACO, and asthma.

Current Knowledge of Asthma-COPD Overlap (ACO) Genetic Risk Factors, Characteristics, and Prognosis

Asthma-COPD overlap (ACO) is a newly identified phenotype of chronic obstructive airway diseases with shared asthma and COPD features. Patients with ACO are poorly defined, and some evidence suggests that they have worse health outcomes and greater disease burden than patients with COPD or asthma. Generally, there is no evidence-based and universal definition for ACO; several consensus documents have provided various descriptions of the phenotype. In addition, the mechanisms underlying the development of ACO are not fully understood. Whether ACO is a distinct clinical entity with its particular discrete genetic determinant different from asthma and COPD alone or an intermediate phenotype with overlapping genetic markers within asthma and COPD spectrum of obstructive airway disease remains unproven. This review summarizes the current knowledge of the genetic risk factors, characteristics, and prognosis of ACO.

Mechanisms and biomarkers of airway epithelial cell damage in asthma: A review

Bronchial asthma is a heterogeneous disease with complex pathological mechanisms representing different phenotypes, including severe asthma. The airway epithelium is a major site of complex pathological changes in severe asthma due, in part, to activation of inflammatory and immune mechanisms in response to noxious agents. Current imaging procedures are unable to accurately measure epithelial and airway remodeling. Damage of airway epithelial cells occurs is linked to specific phenotypes and endotypes which provides an opportunity for the identification of biomarkers reflecting epithelial, and airway, remodeling. Identification of patients with more severe epithelial disruption using biomarkers may also provide personalised therapeutic opportunities and/or markers of successful therapeutic intervention. Here, we review the evidence for ongoing epithelial cell dysregulation in the pathogenesis of asthma, the sentinel role of the airway epithelium and how understanding these molecular mechanisms provides the basis for the identification of candidate biomarkers for asthma prediction, prevention, diagnosis, treatment and monitoring.

ACO (Asthma-COPD Overlap) Is Independent from COPD, a Case in Favor: A Systematic Review

Asthma and chronic obstructive pulmonary disease (COPD) are now recognized to be able to co-exist as asthma-COPD overlap (ACO). It is clinically relevant to evaluate whether patients with COPD concurrently have components of asthma in primary care. This is because: (i) ACO is a relatively common condition among asthma (over 40 years of age) or COPD irrespective of its diagnosis criteria; (ii) patients with ACO can have higher frequency of exacerbation and more rapid decline in lung function than those with asthma or COPD; and (iii) asthmatic features such as eosinophilic airway inflammation are promising indicators for prediction of inhaled corticosteroid-responsiveness in COPD. The aim of this review to evaluate diagnostic markers for ACO. We searched PubMed for articles related to ACO published until 2020. Articles associated with diagnostic biomarkers were included. We identified a total of 25 studies, some of which have revealed that a combination of biomarkers such as fractional exhaled nitric oxide and serum immunoglobulin E is useful to discern type 2 inflammation in the airways of COPD. Here, we review the current understanding of the clinical characteristics, biomarkers and molecular pathophysiology of ACO in the context of how ACO can be differentiated from COPD.

Serum Neutrophil Gelatinase-associated Lipocalin (NGAL) Is Elevated in Patients with Asthma and Airway Obstruction

Neutrophilic airway inflammation is one of the features of severe asthma. Neutrophil gelatinase-associated lipocalin (NGAL), or lipocalin-2, is a glycoprotein associated with neutrophilic inflammation and can be detected in blood. Recently, blood NGAL levels have been reported to be elevated in chronic obstructive pulmonary disease. However, the clinical significance of serum NGAL levels in patients with asthma has not been elucidated. The aim of this study was to explore the association between serum NGAL level and clinical parameters in patients with asthma. Sixty-one non-smoking people with stable asthma were enrolled in this study. All patients underwent blood collection and pulmonary function tests. The associations between serum NGAL levels and clinical parameters were analyzed retrospectively. Serum NGAL levels in patients with asthma and obstructive ventilatory defect were higher than those in patients with asthma without obstructive ventilatory defect (76.4±51.4 ng/mL vs. 39.3±27.4 ng/mL, P=0.0019). Serum NGAL levels were correlated with forced expired flow at 50% of vital capacity %predicted and forced expired flow at 75% of vital capacity %predicted (r=-0.3373, P=0.0078 and r=-0.2900, P=0.0234, respectively). Results of a multiple regression analysis demonstrated that serum NGAL level was independently associated with obstructive ventilatory defect. Serum NGAL levels were elevated in patients with asthma and obstructive ventilatory defect. NGAL may be involved in airway remodeling possibly mediated by neutrophilic inflammation in asthma.

Assessment of Inflammatory Markers in Children with Cow's Milk Allergy Treated with a Milk-Free Diet

Background: The aim of the study was to establish whether the use of a strict milk-free diet in children with cow’s milk allergy, resulting in the resolution of clinical symptoms of the disease, also extinguishes the inflammatory reaction induced by the allergy. Methods: We examined 64 children (aged 3–6 years) with a diagnosed cow’s milk allergy who had been treated with an elimination diet for at least six months and showed remission of the disease’s clinical symptoms as a result of the treatment. The control group consisted of 30 healthy children of the same age following an unrestricted age-appropriate diet. Concentrations of cytokines, calprotectin, and adipokines (leptin, resistin, chemerin, neutrophilic lipocalin associated with gelatinase—NGAL) were determined in the serum samples obtained from the studied children by immunoenzymatic assays. Results: Patients with CMA had significantly higher median values of serum IL-6, TNF-α, resistin, chemerin and NGAL in comparison to the healthy children (p < 0.05, p < 0.001, p < 0.05, p < 0.01, p < 0.001, respectively). Serum concentrations of IL-10, leptin, calprotectin and CRP as well as in WBC count were in the same range in both studied groups. We observed direct statistically significant correlations between levels of IL-10 and CRP (p = 0.005), IL-10 and WBC (p = 0.045), TNF-α and WBC (p = 0.038), calprotectin and WBC (p < 0.001), chemerin and CRP (p < 0.001) as well as between NGAL and WBC (p = 0.002) in children with CMA. Conclusion: The use of a strict milk-free diet by children with CMA, resulting in the resolution of clinical symptoms of the disease, does not seem to extinguish the inflammation induced by the allergy. The findings of this study—elevated IL-6, TNF-α, resistin, chemerin and NGAL levels in patients with CMA—suggest that these parameters seem to be involved in the generation of a low-grade proinflammatory environment observed in cow‘s milk allergy and could be used to monitor the effectiveness of treatment.

Treatment options in type-2 low asthma

Monoclonal antibodies targeting IgE or the type-2 cytokines interleukin (IL)-4, IL-5 and IL-13 are proving highly effective in reducing exacerbations and symptoms in people with severe allergic and eosinophilic asthma, respectively. However, these therapies are not appropriate for 30-50% of patients in severe asthma clinics who present with non-allergic, non-eosinophilic, "type-2 low" asthma. These patients constitute an important and common clinical asthma phenotype, driven by distinct, yet poorly understood pathobiological mechanisms. In this review we describe the heterogeneity and clinical characteristics of type-2 low asthma and summarise current knowledge on the underlying pathobiological mechanisms, which includes neutrophilic airway inflammation often associated with smoking, obesity and occupational exposures and may be driven by persistent bacterial infections and by activation of a recently described IL-6 pathway. We review the evidence base underlying existing treatment options for specific treatable traits that can be identified and addressed. We focus particularly on severe asthma as opposed to difficult-to-treat asthma, on emerging data on the identification of airway bacterial infection, on the increasing evidence base for the use of long-term low-dose macrolides, a critical appraisal of bronchial thermoplasty, and evidence for the use of biologics in type-2 low disease. Finally, we review ongoing research into other pathways including tumour necrosis factor, IL-17, resolvins, apolipoproteins, type I interferons, IL-6 and mast cells. We suggest that type-2 low disease frequently presents opportunities for identification and treatment of tractable clinical problems; it is currently a rapidly evolving field with potential for the development of novel targeted therapeutics.

Asthma-Chronic Obstructive Pulmonary Disease Overlap

Asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO) defines a subgroup of patients with asthma who have persistent airflow obstruction or patients with COPD who may exhibit variable airflow limitation and/or evidence of type 2 inflammation. Additional investigations are needed to determine whether ACO represents a distinct disorder with unique underlying pathophysiology, whether ACO patients should be managed differently from those with asthma or COPD, and whether the diagnosis affects long-term outcomes. This article presents the data about the clinical features of ACO, the current information regarding the underlying pathophysiology of the syndrome, and current understanding of therapeutic options.

Role of Type2 Inflammatory Biomarkers in Chronic Obstructive Pulmonary Disease

Airway inflammation in chronic obstructive pulmonary disease (COPD) is typically thought to be driven by Type1 immune responses, while Type2 inflammation appears to be present in definite proportions in the stable state and during exacerbations. In fact, some COPD patients showed gene expression of Type2 inflammation in the airway, and this subset was associated with the inhaled corticosteroid (ICS) response. Interestingly enough, the relationship between COPD and diseases associated with Type2 inflammation from the perspective of impaired lung development is increasingly highlighted by recent epidemiologic studies on the origin of COPD. Therefore, many researchers have shown an interest in the prevalence and the role of existent Type2 biomarkers such as sputum and blood eosinophils, exhaled nitric oxide fraction, and atopy, not only in asthma but also in COPD. Although the evidence about Type2 biomarkers in COPD is inconsistent and less robust, Type2 biomarkers have shown some potential when analyzing various clinical outcomes or therapeutic response to ICS. In this article, we review the existent and emerging Type2 biomarkers with clinically higher applicability in the management of COPD.

Metabolomic fingerprinting and systemic inflammatory profiling of asthma COPD overlap (ACO)

Background

Asthma-COPD overlap (ACO) refers to a group of poorly studied and characterised patients reporting with disease presentations of both asthma and COPD, thereby making both diagnosis and treatment challenging for the clinicians. They exhibit a higher burden in terms of both mortality and morbidity in comparison to patients with only asthma or COPD. The pathophysiology of the disease and its existence as a unique disease entity remains unclear. The present study aims to determine whether ACO has a distinct metabolic and immunological mediator profile in comparison to asthma and COPD.

Methods

Global metabolomic profiling using two different groups of patients [discovery (D) and validation (V)] were conducted. Serum samples obtained from moderate and severe asthma [n = 34(D); n = 32(V)], moderate and severe COPD [n = 30(D); 32(V)], ACO patients [n = 35(D); 40(V)] and healthy controls [n = 33(D)] were characterized using gas chromatography mass spectrometry (GC-MS). Multiplexed analysis of 25 immunological markers (IFN-γ (interferon gamma), TNF-α (tumor necrosis factor alpha), IL-12p70 (interleukin 12p70), IL-2, IL-4, IL-5, IL-13, IL-10, IL-1α, IL-1β, TGF-β (transforming growth factor), IL-6, IL-17E, IL-21, IL-23, eotaxin, GM-CSF (granulocyte macrophage-colony stimulating factor), IFN-α (interferon alpha), IL-18, NGAL (neutrophil gelatinase-associated lipocalin), periostin, TSLP (thymic stromal lymphopoietin), MCP-1 (monocyte chemoattractant protein- 1), YKL-40 (chitinase 3 like 1) and IL-8) was also performed in the discovery cohort.

Results

Eleven metabolites [serine, threonine, ethanolamine, glucose, cholesterol, 2-palmitoylglycerol, stearic acid, lactic acid, linoleic acid, D-mannose and succinic acid] were found to be significantly altered in ACO as compared with asthma and COPD. The levels and expression trends were successfully validated in a fresh cohort of subjects. Thirteen immunological mediators including TNFα, IL-1β, IL-17E, GM-CSF, IL-18, NGAL, IL-5, IL-10, MCP-1, YKL-40, IFN-γ, IL-6 and TGF-β showed distinct expression patterns in ACO. These markers and metabolites exhibited significant correlation with each other and also with lung function parameters.

Conclusions

The energy metabolites, cholesterol and fatty acids correlated significantly with the immunological mediators, suggesting existence of a possible link between the inflammatory status of these patients and impaired metabolism. The present findings could be possibly extended to better define the ACO diagnostic criteria, management and tailoring therapies exclusively for the disease.

Diagnostic accuracy of periostin in predicting asthma: a systematic review and Meta-analysis

OBJECTIVE

We sought to evaluate the accuracy of periostin for the diagnosis of asthma through a systematic review and meta-analysis.

METHODS

we searched the electronic databases (PubMed, EMBASE, Web of science) to find relevant studies through December 31, 2018. Studies selecting, data extraction and quality assessment were conducted by two researchers independently according to inclusion and exclusion criteria. We used bivariate mixed effects model to conduct the meta-analysis.

RESULTS

A total of 9 studies including 1448 subjects with asthma were analyzed. The pooled sensitivity, specificity, diagnostic odds ratio (DOR) were 0.68 (95% CI, 0.42-0.86), 0.87 (95% CI, 0.76-0.93) and 13.78 (95% CI, 4.64-40.93) respectively. The area under the summary receiver operating curves (SROC) was 0.87 (95% CI, 0.84-0.90). The Spearman correlation coefficient indicated that no threshold effect existed in the included studies. The study design had statistical significance for sensitivity results (p < 0.001) through regression analysis. Heterogeneity might be caused by non-threshold effect.

CONCLUSION

Periostin has moderate accuracy in the diagnosis of asthma.

A robust strategy for proteomic identification of biomarkers of invasive phenotype complexed with extracellular heat shock proteins

As an extension of their orchestration of intracellular pathways, secretion of extracellular heat shock proteins (HSPs) is an emerging paradigm of homeostasis imperative to multicellular organization. Extracellular HSP is axiomatic to the survival of cells during tumorigenesis; proportional representation of specific HSP family members is indicative of invasive potential and prognosis. Further significance has been added by the knowledge that all cancer-derived exosomes have surface-exposed HSPs that reflect the membrane topology of cells that secrete them. Extracellular HSPs are also characteristic of chronic inflammation and sepsis. Accordingly, interrogation of extracellular HSPs secreted from cell culture models may represent a facile means of identifying translational biomarker signatures for targeting in situ. In the current study, we evaluated a simple peptide-based multivalent HSP affinity approach using the Vn96 peptide for low speed pelleting of HSP complexes from bioreactor cultures of cell lines with varying invasive phenotype in xenotransplant models: U87 (glioblastoma multiforme; invasive); HELA (choriocarcinoma; minimally invasive); HEK293T (virally transformed immortalized; embryonic). Proteomic profiling by bottom-up mass spectrometry revealed a comprehensive range of candidate biomarkers including primary HSP ligands. HSP complexes were associated with additional chaperones of prognostic significance such as protein disulfide isomerases, as well as pleiotropic metabolic enzymes, established as proportionally reflective of invasive phenotype. Biomarkers of inflammatory and mechanotransductive phenotype were restricted to the most invasive cell model U87, including chitinase CHI3L1, lamin C, amyloid derivatives, and histone isoforms.

Diagnostic value of serum neutrophil gelatinase-associated lipocalin, interleukin-6 and anti-citrullinated alpha-enolase peptide 1 for lower respiratory tract infections

OBJECTIVES

The aim of this study was to explore the auxiliary diagnostic value of neutrophil gelatinase-associated lipocalin (NGAL) and anti-citrullinated alpha-enolase peptide 1 (CEP-1) in lower respiratory tract infections (LRTIs).

METHODS

Blood samples were collected from 99 in-patients with LRTIs [62 community-acquired pneumonia (CAP), 14 acute exacerbated chronic obstructive pulmonary diseases (AECOPD), 23 other diseases] and 50 healthy subjects. NGAL, CEP-1 and IL-6 were measured and compared. IL-6 was tested by electrochemiluminescence assay kit on Roche E601 immunology analyzer, CEP-1 was assessed with enzyme-linked immunosorbent assay kit, and NGAL was detected by latex immunoturbidimetric assay kit on Beckman Coulter AU2700.

RESULTS

Compared with healthy controls, NGAL and IL-6 levels were significantly increased in the patients with LRTIs, the area under the curves (AUC) was 0.97 and 0.88 respectively (P < 0.01). The sensitivity and specificity of NGAL at a cut-off of 86 ng/ml were 93.0% and 96.0%, respectively, in which the sensitivity was consistent with IL-6 (P = 0.21) and the specificity was better than IL-6 (P < 0.01). CEP-1 slightly increases in the patient group, however the difference was not significant (P = 0.41). The levels of NGAL and IL-6 was no differences in different diseases, the P-value was 0.50 and 0.29, respectively. LRTIs with and without underlying diseases have similar NGAL and IL-6 values.

CONCLUSIONS

NGAL, rather than CEP-1, may be appealing adjuncts for diagnosis of LRTIs. NGAL proved to be a better biomarker than IL-6.

Eicosanoids metabolized through LOX distinguish asthma-COPD overlap from COPD by metabolomics study

Background and objective

The prevalence of asthma is greater than 20% in patients previously diagnosed with COPD. Patients with asthma–COPD overlap (ACO) are at risk of rapid progression of disease and severe exacerbations. However, in some patients with ACO, a clear distinction from COPD is very difficult by using physiological testing techniques. This study aimed to apply a novel metabolomic approach to identify the metabolites in sera in order to distinguish ACO from COPD.

Methods

In the study, blood samples were collected from patients with COPD, ACO, and healthy controls. Cholamine derivatization-ultrahigh performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) was used to investigate serum metabolites of eicosanoids.

Results

A clear intergroup separation existed between the patients with ACO and those with COPD, while ACO tends to have higher serum metabolic levels of eicosanoids. A robust Orthogonal Projections to Latent Structures-Discriminant Analysis (OPLS-DA) model was found for discriminating between ACO and COPD (R2Y =0.81, Q2=0.79). In addition, there is a significant correlation between some metabolites and clinical indicators, such as hydroxyeicosatetraenoic acids (HETEs), hydroperoxyeicosatetraenoic acids (HPETEs) and FEV1/FVC. The higher values of area under the receiver operating characteristic curves (ROC) of HETEs, which were metabolized from HPETEs through lipoxygenase (LOX), indicated that they should be the potential biomarkers to distinguish ACO from COPD.

Conclusion

Eicosanoids can clearly discriminate different biochemical metabolic profiles between ACO and COPD. The results possibly provide a new perspective to identify potential biomarkers of ACO and may be helpful for personalized treatment.

Airway mycosis in allergic airway disease

The allergic airway diseases, including chronic rhinosinusitis (CRS), asthma, allergic bronchopulmonary mycosis (ABPM) and many others, comprise a heterogeneous collection of inflammatory disorders affecting the upper and lower airways and lung parenchyma that represent the most common chronic diseases of humanity. In addition to their shared tissue tropism, the allergic airway diseases are characterized by a distinct pattern of inflammation involving the accumulation of eosinophils, type 2 macrophages, innate lymphoid cells type 2 (ILC2), IgE-secreting B cells, and T helper type 2 (Th2) cells in airway tissues, and the prominent production of type 2 cytokines including interleukin (IL-) 33, IL-4, IL-5, IL-13, and many others. These factors and related inflammatory molecules induce characteristic remodeling and other changes of the airways that include goblet cell metaplasia, enhanced mucus secretion, smooth muscle hypertrophy, tissue swelling and polyp formation that account for the major clinical manifestations of nasal obstruction, headache, hyposmia, cough, shortness of breath, chest pain, wheezing, and, in the most severe cases of lower airway disease, death due to respiratory failure or disseminated, systemic disease. The syndromic nature of the allergic airway diseases that now include many physiological variants or endotypes suggests that distinct endogenous or environmental factors underlie their expression. However, findings from different perspectives now collectively link these disorders to a single infectious source, the fungi, and a molecular pathogenesis that involves the local production of airway proteinases by these organisms. In this review, we discuss the evidence linking fungi and their proteinases to the surprisingly wide variety of chronic airway and systemic disorders and the immune pathogenesis of these conditions as they relate to environmental fungi. We further discuss the important implications these new findings have for the diagnosis and future therapy of these common conditions.

Chitinase-like protein YKL-40 correlates with inflammatory phenotypes, anti-asthma responsiveness and future exacerbations

Background

Asthma is a heterogeneous chronic airway disease, which may be classified into different phenotypes. YKL-40 is a chitin-binding glycoprotein with unclear functions, but its expression is associated with inflammation and tissue remodeling. However, few studies have explored whether YKL-40 is associated with inflammatory phenotypes of asthma.

Methods

The study had two parts. Study I (n = 115) was a one-year prospective cohort designed to explore the relationship of serum YKL-40 levels with inflammatory phenotypes of asthma at baseline, and during exacerbations. Study II (n = 62) was a four-week prospective cohort designed to define whether serum YKL-40 levels could predict responses to a fixed anti-asthma regimen. YKL-40, IL-6 and CCL22 levels were detected using ELISA, and a sputum inflammatory panel (including IL-1β, IL-5, IL-8 and TNF-α) was assessed using Luminex-based MILLIPLEX assay.

Results

Study I: Serum YKL-40 levels in non-eosinophilic asthma (NEA) i.e. neutrophilic (47.77 [29.59, 74.97] ng/mL, n = 40) and paucigranulocytic (47.36 [28.81, 61.68] ng/mL, n = 31) were significantly elevated compared with eosinophilic asthma (31.05 [22.41, 51.10] ng/mL, n = 44) (P = 0.015). Serum YKL-40levels positively correlated with blood neutrophils, sputum IL-1β and plasma IL-6 but negatively correlated with serum IgE and blood eosinophils (all P ≤ 0.05). Baseline YKL-40 levels predicted moderate to severe exacerbations within a one-year period (aOR = 4.13, 95% CI = [1.08, 15.83]). Study II: Serum YKL-40 was an independent biomarker of negative responses to anti-asthma regimens (adjusted Odds Ratio [aOR] = 0.82, 95% CI = [0.71, 0.96].

Conclusions

These studies show that YKL-40 is a non-type 2 inflammatory signature for NEA, which could predict responsiveness or insensitivity to anti-asthma medications and more exacerbations. Further studies are needed to assess whether monitoring YKL-40 levels could provide potential implications for clinical relevance.

Electronic supplementary material

The online version of this article (10.1186/s12931-019-1051-9) contains supplementary material, which is available to authorized users.

Biomarkers in asthma: state of the art

Asthma is a heterogenous disease characterized by multiple phenotypes driven by different mechanisms. The implementation of precision medicine in the management of asthma requires the identification of phenotype-specific markers measurable in biological fluids. To become useful, these biomarkers need to be quantifiable by reliable systems, reproducible in the clinical setting, easy to obtain and cost-effective. Using biomarkers to predict asthma outcomes and therapeutic response to targeted therapies has a great clinical significance, particularly in severe asthma. In the last years, significant research has been realized in the identification of valid biomarkers for asthma. This review focuses on the existent and emerging biomarkers with clinical higher applicability in the management of asthma.

Neutrophil gelatinase-associated lipocalin as a complementary biomarker for the asthma-chronic obstructive pulmonary disease overlap

Background

There is no standardized definition of the asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO). Although the blood eosinophil count is regarded as a biomarker for identifying ACO, it has no distinct value. This study aimed to measure plasma levels of neutrophil gelatinase-associated lipocalin (NGAL), a potential biomarker for distinguishing between ACO and non-ACO COPD.

Methods

We used the Korean cohort in the COPD in dusty area (CODA) study which included 137 subjects with COPD confirmed by spirometry. We defined ACO by a positive bronchodilator response (forced expiratory volume in 1 s, FEV₁ >12% and >200 mL from baseline) or based on a previous history of asthma. Plasma levels of NGAL were determined by enzyme immunoassay.

Results

Among the 137 subjects, 77 were ACO and 60 were non-ACO COPD. Overall, the plasma NGAL levels were 15.9±7.9 and 15.6±6.6 ng/mL for non-ACO and ACO subjects respectively, and not significantly different. However, NGAL levels were significantly higher in female subjects with ACO (17.0±6.4 vs. 11.1±4.5, P=0.01). In female subjects, NGAL levels showed a good predictive ability to discriminate between ACO and non-ACO COPD [area under the receiver operating characteristic curve (AUROC), 0.77]; the predictive ability was similar to that of the blood eosinophil count (AUROC, 0.79). There was a higher probability of discriminating ACO from non-ACO among subjects in the highest tertile of NGAL levels (odds ratio, 1.72; 95% confidence interval, 0.69-4.28; P for trend =0.01).

Conclusions

NGAL levels were significantly higher in ACO compared to non-ACO COPD in female subjects. After adjusting for gender as a confounding factor, the ability to distinguish ACO was better at higher levels of NGAL.

Combined Assessment of Serum Periostin and YKL-40 May Identify Asthma-COPD Overlap

BACKGROUND

Asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO) has been proposed as a different diagnosis from asthma and COPD. However, little is known about the role of serum biomarkers in ACO.

OBJECTIVE

To evaluate serum periostin, a type 2 biomarker, and serum chitinase-3-like protein 1 (YKL-40), a useful biomarker for COPD, in Japanese patients with asthma, ACO, or COPD, and investigate the role of these biomarkers in identifying ACO.

METHODS

Subjects included Japanese patients with asthma (n = 177), ACO (n = 115), or COPD (n = 61). Serum periostin, YKL-40, and total IgE, blood eosinophils, and fractional exhaled nitric oxide were measured and compared among the patients.

RESULTS

Serum periostin was high in both asthma and ACO, but not in COPD, whereas serum YKL-40 was high in both COPD and ACO, but not in asthma. Serum periostin levels correlated weakly with eosinophil counts in asthma, ACO, and COPD. Multivariate linear regression analysis revealed that older age, lower body mass index, higher eosinophil counts, higher total IgE, and the absence of the diagnosis of COPD were significantly associated with higher periostin levels. Based on cutoff values derived by receiver operating characteristic analysis (periostin: 55.1 ng/mL; YKL-40: 61.3 ng/mL), patients were classified into high or low groups. The proportion of patients with both high serum periostin and YKL-40 levels was significantly higher in ACO than in asthma or COPD.

CONCLUSIONS

Serum periostin levels were comparable between asthma and ACO, whereas YKL-40 was comparable between ACO and COPD. Combined assessment of serum periostin and YKL-40 may identify ACO.