Usefulness of diurnal variation of fractional exhaled nitric oxide for predicting early therapeutic response to asthma treatment.

OBJECTIVE: Fractional exhaled nitric oxide (FeNO) is considered to be an adjunct for asthma management, although its usefulness remains controversial. Therefore, it may be necessary for new approaches to use FeNO for asthma management. We evaluated whether diurnal variations of FeNO can predict response to asthma treatment. METHODS: This pilot study consisted of 22 uncontrolled asthmatics and 16 healthy subjects. FeNO and peak expiratory flow (PEF) were measured by themselves twice daily at home for three weeks (asthmatics) or two weeks (healthy subjects), and daily mean and diurnal variations of FeNO and PEF levels were calculated. In uncontrolled asthmatics, treatment was intensified a week after study entry, and then control status was reevaluated after three to four weeks. Asthmatics were then divided into two groups; good or poor responders. RESULTS: Diurnal variations of FeNO levels, as well as daily mean FeNO and PEF levels, in uncontrolled asthmatics before intensive treatment were significantly higher than those in healthy subjects, regardless of treatment response (p < 0.01). Furthermore, in the good responders, diurnal variations of FeNO levels were significantly decreased in the 1st week (p < 0.05) of intensive treatment, whereas the daily mean FeNO levels significantly dropped in the 2nd week (p < 0.05). In the poor responders, no such changes were observed in FeNO levels. In terms of PEF, only the daily mean levels were significantly elevated after the initiation of intensive treatment, regardless of treatment response. CONCLUSIONS: Diurnal variations of FeNO may contribute to predicting early therapeutic response to asthma treatment.

Hydrogen sulfide as a novel biomarker of asthma and chronic obstructive pulmonary disease.

Hydrogen sulfide (H2S) has recently been recognised as the third important gas-signalling molecule, besides nitric oxide and carbon monoxide. H2S has been reported to be produced by many cell types in mammalian tissues and organs throughout the actions of H2S-generating enzymes or redox reactions between the oxidation of glucose and element of sulfur. Although the pathological role of H2S has not yet been fully elucidated, accumulative data suggest that H2S may have biphasic effects. Briefly, it mainly has anti-inflammatory and antioxidant roles, although it can also have pro-inflammatory effects under certain conditions where rapid release of H2S in tissues occur, such as sepsis. To date, there have been several clinical studies published on H2S in respiratory disorders, including asthma and chronic obstructive pulmonary disease (COPD). According to previous studies, H2S is detectable in serum, sputum, and exhaled breath, although a gold standard method for detection has not yet been established. In asthma and COPD, H2S levels in serum and sputum can vary depending on the underlying conditions such as an acute exacerbation. Furthermore, sputum H2S in particular correlates with sputum neutrophils and the degree of airflow limitation, indicating that H2S has potential as a novel promising biomarker for neutrophilic airway inflammation for predicting current control state as well as future risks of asthma. In the future, concurrent measures of H2S with conventional inflammatory biomarkers (fractional exhaled nitric oxide, eosinophils etc) may provide more useful information regarding the identification of inflammatory phenotypes of asthma and COPD for personalised treatment.

Comparison of fractional exhaled nitric oxide levels measured by different analyzers produced by different manufacturers.

Objective: Fractional exhaled nitric oxide (FeNO) is widely used as a biomarker of allergic airway inflammation. At present, both stationary chemiluminescence and portable electrochemical analyzers produced by different manufacturers are available. However, it remains debatable whether those analyzers are comparable to each other. We compare FeNO levels obtained by different analyzers.Methods: For the first study, 153 subjects were enrolled to compare differences in FeNO levels measured using three analyzers (NA623NP®, NObreath®, and NIOX MINO®) which were produced by different manufacturers. For the second study, 30 subjects were recruited to compare FeNO levels obtained by the two analyzers (NIOX MINO® and NIOX VERO®) produced by the same manufacturer. FeNO was measured twice using each analyzer in random order.Results: FeNO levels obtained using the NIOX MINO® and NObreath® were more variable than those measured using the NA623NP®. There were strong positive correlations in FeNO levels measured by the NA623NP®, NIOX MINO®, and NObreath® (p < 0.001). The NA623NP® and NIOX MINO® provided the highest and lowest FeNO levels, respectively; whereas, those obtained by NObreath® were intermediate. No significant differences were observed in FeNO levels obtained using the NIOX MINO® and NIOX VERO®.Conclusions: FeNO levels measured by the NIOX MINO® and NIOX VERO®, both of which were produced by the same manufacturer, have comparability. However, significant differences in FeNO levels exist when measured by analyzers manufactured by different manufacturers. This should be taken into account for FeNO measurement.

A Serological Biomarker of Versican Degradation is Associated with Mortality Following Acute Exacerbations of Idiopathic Interstitial Pneumonia.

BACKGROUND: Idiopathic interstitial pneumonia (IIP) is characterized by an increased rate of extracellular matrix (ECM) remodeling resulting in fibrosis. Acute exacerbations of IIP represent periods of increased disease activity, thus we hypothesized that ECM remodeling was altered during acute exacerbations and investigated this by serological neo-epitope biomarkers. METHODS: Patients who were sequentially admitted to the hospital with acute exacerbations of IIP were retrospectively analyzed for ECM remodeling at time of exacerbation (AE-IIP) and at clinical stability (S-IIP). Biomarkers released by matrix metalloproteinase-mediated degradation of collagen type I (C1M), III (C3M), IV (C4M), and VI (C6M), elastin (ELM7), versican (VCANM), biglycan (BGM), and C-reactive protein (CRPM) were assessed in serum by competitive ELISAs utilizing neo-epitope specific monoclonal antibodies. RESULTS: Sixty-eight patients at AE-IIP and 29 at S-IIP were included in this retrospective analysis. Of these, 28 and 11 patients, respectively, had idiopathic pulmonary fibrosis. At AE-IIP, serum levels of C4M (p = 0.002) and C6M (p = 0.024) were increased as compared with S-IIP, while ELM7 (p = 0.024) and VCANM (p < 0.0001) were decreased. Lower VCANM levels at AE-IIP were associated with increased risk of mortality (HR 0.64 [95% CI 0.43-0.94], p = 0.022). CONCLUSIONS: The ECM remodeling profile was significantly altered during acute exacerbations of IIP, and a biomarker of versican degradation was related to mortality outcome. These results indicate that biomarkers of ECM remodeling may be useful in the non-invasive evaluation of acute exacerbations of IIP. Especially versican degradation, as measured serologically by VCANM, may have prognostic potential and help guide treatment for acute exacerbations.

The clinical role of fractional exhaled nitric oxide in asthma control.

BACKGROUND: The potential role and characteristics of fractional exhaled nitric oxide (FeNO) remain unclear in the treatment of asthma. OBJECTIVE: To explore the clinical role of FeNO in asthmatic treatment. METHODS: We evaluated whether the mean or change of FeNO levels in the treatment period is associated with other conventional control parameters and predicted some clinical outcomes of asthma. We retrospectively analyzed the mean and percentage change of FeNO levels in the first 5 measurements at our hospital. RESULTS: The study found a significantly strong correlation between FeNO level at diagnosis and the largest changes of FeNO values from diagnosis. No significant correlations were observed between FeNO levels and other parameters (Asthma Control Test [ACT] score or forced expiratory volume in one second [FEV1]) in mean and percentage change of values under treatment of asthma; however, significant positive correlations were found between ACT scores and FEV1. The mean FeNO level revealed a significant negative correlation with an annual change in FEV1 in individuals with asthma who were followed up for more than 2 years. Both the mean ACT score and percent predicted FEV1 revealed a significant negative correlation with occasional use of systemic corticosteroids. CONCLUSION: During conventional treatment of asthma, the largest changes of FeNO values from diagnosis were strongly correlated with FeNO levels at diagnosis. As for the unlikely conventional parameters, no significant associations were observed between FeNO levels and deterioration of asthma during the treatment periods. An elevated mean FeNO level may be a marker of decreased lung function in individuals with asthma.

Japanese guidelines for adult asthma 2017.

Adult bronchial asthma is characterized by chronic airway inflammation, and presents clinically with variable airway narrowing (wheezes and dyspnea) and cough. Long-standing asthma induces airway remodeling, leading to intractable asthma. The number of patients with asthma has increased; however, the number of patients who die of asthma has decreased (1.2 per 100,000 patients in 2015). The goal of asthma treatment is to enable patients with asthma to attain normal pulmonary function and lead a normal life, without any symptoms. A good relationship between physicians and patients is indispensable for appropriate treatment. Long-term management by therapeutic agents and elimination of the causes and risk factors of asthma are fundamental to its treatment. Four steps in pharmacotherapy differentiate between mild and intensive treatments; each step includes an appropriate daily dose of an inhaled corticosteroid, varying from low to high levels. Long-acting ß2-agonists, leukotriene receptor antagonists, sustained-release theophylline, and long-acting muscarinic antagonist are recommended as add-on drugs, while anti-immunoglobulin E antibody and oral steroids are considered for the most severe and persistent asthma related to allergic reactions. Bronchial thermoplasty has recently been developed for severe, persistent asthma, but its long-term efficacy is not known. Inhaled ß2-agonists, aminophylline, corticosteroids, adrenaline, oxygen therapy, and other approaches are used as needed during acute exacerbations, by choosing treatment steps for asthma in accordance with the severity of exacerbations. Allergic rhinitis, eosinophilic chronic rhinosinusitis, eosinophilic otitis, chronic obstructive pulmonary disease, aspirin-induced asthma, and pregnancy are also important issues that need to be considered in asthma therapy.

Exhaled nitric oxide and inducible nitric oxide synthase gene polymorphism in Japanese asthmatics.

BACKGROUND: Inducible nitric oxide synthase (iNOS) induced by inflammatory cytokines and iNOS activity in bronchial epithelial cells is a major determinant of fractional exhaled nitric oxide (FeNO) levels. The aim of this study was to investigate the association of iNOS promoter gene polymorphisms and FeNO levels in Japanese asthmatics before the introduction of asthma treatment. METHODS: Asthmatics were recruited from Fukushima Medical University Hospital. Genotyping of the pentanucleotide repeat (CCTTT)n and seven previously detected single nucleotide polymorphisms (SNPs) in the iNOS promoter lesion was performed. The relationships between the genotypes and FeNO levels before the introduction of asthma treatment were compared. RESULTS: In 91 asthmatics, the number of microsatellite repeats ranged from 9 to 20 and showed a bimodal distribution. According to this distribution, asthmatics were divided into two groups: genotypes with at least one long allele with more than 14 repeats (L/s or L/L) and genotypes with both short alleles with 14 or fewer repeats (s/s). No significant differences were observed in each parameter between the two groups. The mean FeNO level before treatment was significantly higher in the L/s or L/L subjects than in the s/s subjects. After treatment, the lowest FeNO level did not differ between the two groups. Three SNPs detected in the Japanese subjects were not associated with FeNO levels. CONCLUSIONS: The number of CCTTT repeats in the iNOS promoter region was associated with FeNO levels in asthmatics before treatment, suggesting the importance of iNOS genotype in the clinical application of FeNO for asthmatics.

Serum Syndecan-4 as a Possible Biomarker in Patients With Acute Pneumonia.

BACKGROUND: Syndecan-4 is a transmembrane heparan sulfate proteoglycan expressed in a variety of cells, and glycosaminoglycan side chains of syndecan-4 bind to several proteins, suggesting several biological functions. However, the role of syndecan-4 in acute bacterial pneumonia has not yet been elucidated. METHODS: Serum syndecan-4 levels were measured in patients with acute pneumonia, and the relationships between serum syndecan-4 levels and clinical parameters were analyzed. Next, we treated wild-type and syndecan-4-deficient mice with Streptococcus pneumoniae intranasally and analyzed the phenotype of syndecan-4-deficient mice. RESULTS: In the patients with acute pneumonia, serum syndecan-4 levels were significantly higher than in the healthy volunteers and correlated negatively with the pneumonia severity score. In addition, in patients who improved with short-term antibiotic therapy, serum syndecan-4 levels were higher on admission and gradually increased during antibiotic therapy. Furthermore, in syndecan-4-deficient mice, the survival rate was significantly worse, and total neutrophil counts in bronchoalveolar lavage fluid, bacterial counts in blood, and plasma levels of inflammatory cytokines were significantly higher than in wild-type mice. CONCLUSIONS: These results suggest that syndecan-4 has an anti-inflammatory function in acute pneumonia and could serve as a useful biomarker in these patients.

Association of asthma education with asthma control evaluated by asthma control test, FEV1, and fractional exhaled nitric oxide.

BACKGROUND: Asthma education is an important adjunct for asthma control although the way asthma education affects asthma outcomes is poorly understood. The asthma control test (ACT), forced expiratory volume in 1 s (FEV(1)), and fractional exhaled nitric oxide (FeNO) have all been used as markers of asthma control. However, the use of FeNO as a surrogate marker remains controversial. OBJECTIVES: (i) To examine whether asthma education is associated with asthma control; (ii) to compare absolute levels and changes of ACT, FEV(1), and FeNO over a year; and (iii) to evaluate whether FeNO can be used as an additional marker of asthma control. METHODS: Fifty asthmatics with poor adherence (12 mild, 21 moderate, and 17 severe) received asthma education at study entry. Medications were unchanged for the first 3 months, and ACT, FEV(1), and FeNO measurements were recorded at entry, 3, 6, and 12 months. Asthma control was assessed at each visit and patients were categorized as either "stable" or "unstable" asthmatics according to the global initiative for asthma (GINA) guidelines. RESULTS: A significant decrease in FeNO and increase in ACT score were noted in the stable asthmatic group at 3 months (p < .001), and this persisted over 12 months. Significant correlations were seen between changes (Δ) in FeNO, ACT, and FEV(1) over time. However, significant correlations between the absolute levels were not maintained over 12 months. A decrease of ≥18.6% in FeNO and a ≥3-point increase in ACT score (sensitivity: 80% and 73.3% and specificity: 83.3% and 87.5%, respectively) were associated with stable asthma control although the absolute levels were not. CONCLUSIONS: Asthma education may be useful to achieve stable control. In addition, changes rather than absolute levels of FeNO and ACT may be better markers of asthma control.

Clinical significance of serum hyaluronan in chronic fibrotic interstitial pneumonia.

BACKGROUND AND OBJECTIVE: Hyaluronan is an important constituent of the extracellular matrix in lungs, and growing evidence demonstrates its important biological properties in the lung. However, its role in interstitial pneumonia remains to be fully clarified. The goal of this study was to clarify the role of hyaluronan in interstitial pneumonia. METHODS: Hyaluronan in serum and bronchoalveolar lavage (BAL) fluid of chronic interstitial pneumonia (CIP) patients was measured, and the correlation with clinical parameters was determined. In addition, the correlation between hyaluronan in serum and clinical parameters was analysed in patients with acute exacerbation of interstitial pneumonia (IP-AE). RESULTS: When compared with healthy controls, serum hyaluronan was significantly greater in patients with CIP and was positively correlated with serum biomarkers of inflammation and fibrosis, such as C-reactive protein and surfactant protein-D. In BAL fluid, the amount of hyaluronan was positively correlated with the percentage of inflammatory cells and the amount of CXCL8. When compared with CIP patients, patients with IP-AE had significantly greater amounts of serum hyaluronan, and patients with the highest serum hyaluronan had the worst 60-day outcomes. CONCLUSIONS: This work suggests that serum hyaluronan may be a clinically useful biomarker of interstitial pneumonia and suggests the possibility that hyaluronan is involved in the pathogenesis of interstitial pneumonia by recruiting inflammatory cells into the lungs.

Syndecan-4 regulates early neutrophil migration and pulmonary inflammation in response to lipopolysaccharide.

Proteoglycans (PGs) and their associated glycosaminoglycan side chains are effectors of inflammation, but little is known about changes to the composition of PGs in response to lung infection or injury. The goals of this study were to identify changes to heparan sulfate PGs in a mouse model of gram-negative pneumonia, to identify the Toll-like receptor adaptor molecules responsible for these changes, and to determine the role of the heparan sulfate PG in the innate immune response in the lungs. We treated mice with intratracheal LPS, a component of the cell wall of gram-negative bacteria, to model gram-negative pneumonia. Mice treated with intratracheal LPS had a rapid and selective increase in syndecan-4 mRNA that was regulated through MyD88-dependent mechanisms, whereas expression of several other PGs was not affected. To determine the role of syndecan-4 in the inflammatory response, we exposed mice deficient in syndecan-4 to LPS and found a significant increase in neutrophil numbers and amounts of CXC-chemokines and total protein in bronchoalveolar lavage fluid. In studies performed in vitro, macrophages and epithelial cells treated with LPS had increased expression of syndecan-4. Studies performed using BEAS-2B cells showed that pretreatment with heparin and syndecan-4 decreased the expression of CXCL8 mRNA in response to LPS and TNF-α. These findings indicate that the early inflammatory response to LPS involves marked up-regulation of syndecan-4, which functions to limit the extent of pulmonary inflammation and lung injury.

Exhaled nitric oxide (FeNO) as a non-invasive marker of airway inflammation.

Nitric oxide (NO), previously very famous for being an environmental pollutant in the field of pulmonary medicine, is now known as the smallest, lightest, and most famed molecule to act as a biological messenger. Furthermore, recent basic researches have revealed the production mechanisms and physiological functions of nitric oxide in the lung, and clinical researches have been clarifying its tight relation to airway inflammation in asthma. On the bases of this knowledge, fractional nitric oxide (FeNO) has now been introduced as one of the most practical tools for the diagnosis and management of bronchial asthma.

Virtual bronchoscopic navigation combined with endobronchial ultrasound to diagnose small peripheral pulmonary lesions: a randomised trial.

BACKGROUND: Bronchoscopy using endobronchial ultrasound (EBUS) can help to diagnose small peripheral pulmonary lesions. However, although biopsy sites can be confirmed, a bronchoscope cannot be guided in EBUS. Virtual bronchoscopic navigation (VBN) can guide a bronchoscope with virtual images, but its value has not been confirmed. METHODS: This prospective multicentre study examines the value of VBN-assisted EBUS for diagnosing small peripheral pulmonary lesions. 199 patients with small peripheral pulmonary lesions (diameter ≤30 mm) were randomly assigned to VBN-assisted (VBNA) or non-VBN-assisted (NVBNA) groups. A bronchoscope was introduced into the target bronchus of the VBNA group using the VBN system. Sites of specimen sampling were verified using EBUS with a guide sheath under fluoroscopy. RESULTS: The diagnostic yield was higher for the VBNA than for the NVBNA group (80.4% vs 67.0%; p = 0.032). The duration of the examination and time elapsed until the start of sample collection were reduced in the VBNA compared with the NVBNA group (median (range), 24.0 (8.7-47.0) vs 26.2 (11.6-58.6) min, p = 0.016) and 8.1 (2.8-39.2) vs 9.8 (2.3-42.3) min, p = 0.045, respectively). The only adverse event was mild pneumothorax in a patient from the NVBNA group. CONCLUSIONS: The diagnostic yield for small peripheral pulmonary lesions is increased when VBN is combined with EBUS. Clinical trial number UMIN000000569.

Uteroglobulin-related protein 1 and severity of respiratory syncytial virus infection in children admitted to hospital.

There are several reports suggesting that genetic factors contribute to the severity of infection with the respiratory syncytial virus (RSV). Infants hospitalized with lower respiratory tract infection (LRTI) due to RSV are at a significantly increased risk for both recurrent wheezing and childhood asthma. Uteroglobin-related protein 1 (UGRP1) is a secretory protein expressed in the airways, and speculated to have anti-inflammatory activity. The presence of the -112G/A polymorphism in the UGRP1 promoter was found to have a significant correlation with asthma phenotype. Also plasma UGRP1 levels were shown to be associated both with this polymorphism and the severity of asthma. The study population consisted of 62 previously healthy infants, ≤12 months of age, who were hospitalized with RSV LRTI, and a control group of 99 healthy adults. Genotyping was performed by restriction fragment length polymorphism. UGRP1 serum levels were determined using ELISA. There were no significant differences in the overall distribution of UGRP1 -112G/A polymorphism genotypes or alleles between the hospitalized infants and healthy adults. A comparison of serum UGRP1 concentration measured at the time of admission and discharge between patients with and without the -112A allele revealed that there was no relation between the presence of the -112A allele and serum UGRP1 in hospitalized infants with RSV infection. Furthermore, there was no relationship between severity of RSV infection and genotype or serum UGRP1 concentration. These results suggest that UGRP1 does not have a major role in the development of severe RSV infection.

Validation study of asthma screening criteria based on subjective symptoms and fractional exhaled nitric oxide.

BACKGROUND: In the latest Global Initiative for Asthma guideline, neither sputum eosinophilia nor fractional exhaled nitric oxide (FeNO) have been evaluated prospectively as an aid in asthma diagnosis, but these measurements are being evaluated for potential use in determining optimal treatment. OBJECTIVE: To report criteria for screening asthma using subjective symptoms and FeNO levels and results of a prospective validation study using these criteria. METHODS: Sixty-one outpatients with recurrent cough, wheezing, or dyspnea underwent measurements of FeNO levels, pulmonary function, methacholine airway responsiveness, and inflammatory cells in induced sputum. The sensitivity, specificity, and concordance achieved using the FeNO-based criteria (at least 1 of the following subjective symptoms: recurrent cough, wheezing, or dyspnea and/or FeNO level ≥ 40 ppb) were analyzed and compared with the values obtained using conventional asthma diagnostic criteria, which includes subjective symptoms with any 2 of the following conditions: airway hyperresponsiveness, reversible airflow limitation, and eosinophilia in induced sputum. RESULTS: Of the 61 patients, 41 were diagnosed as having asthma by the conventional criteria, and 33 were diagnosed as having asthma by the FeNO-based criteria, which showed a sensitivity of 78.6%, a specificity of 89.5%, and a concordance rate of 0.62. Nine of 42 patients were misdiagnosed as not having asthma by FeNO-based criteria (mean [SD] FeNO level, 23.9 [8.0] ppb). Seven of 9 patients were diagnosed as having nonatopic asthma according to IgE levels. CONCLUSIONS: Asthma may be accurately diagnosed in daily practice on the basis of subjective symptoms and FeNO levels, particularly in atopic patients.