Tsuyoshi Oguma

Increased periostin associates with greater airflow limitation in patients receiving inhaled corticosteroids.

BACKGROUND Periostin, an extracellular matrix protein, contributes to subepithelial thickening in asthmatic airways, and its serum levels reflect airway eosinophilic inflammation. However, the relationship between periostin and the development of airflow limitation, a functional consequence of airway remodeling, remains unknown. OBJECTIVE We aimed to determine the relationship between serum periostin levels and pulmonary function decline in asthmatic patients on inhaled corticosteroid (ICS) treatment. METHODS Two hundred twenty-four asthmatic patients (average age, 62.3 years) treated with ICS for at least 4 years were enrolled. Annual changes in FEV1, from at least 1 year after the initiation of ICS treatment to the time of enrollment or later (average, 16.2 measurements over 8 years per individual), were assessed. At enrollment, clinical indices, biomarkers that included serum periostin, and periostin gene polymorphisms were examined. Associations between clinical indices or biomarkers and a decline in FEV1 of 30 mL or greater per year were analyzed. RESULTS High serum periostin levels (≥ 95 ng/mL) at enrollment, the highest treatment step, higher ICS daily doses, a history of admission due to asthma exacerbation, comorbid or a history of sinusitis, and ex-smoking were associated with a decline in FEV1 of 30 mL or greater per year. Multivariate analysis showed that high serum periostin, the highest treatment step, and ex-smoking were independent risk factors for the decline. Polymorphisms of periostin gene were related to higher serum periostin levels (rs3829365) and a decline in FEV1 of 30 mL or greater per year (rs9603226). CONCLUSIONS Serum periostin appears to be a useful biomarker for the development of airflow limitation in asthmatic patients on ICS.

Impact of Exacerbations on Emphysema Progression in Chronic Obstructive Pulmonary Disease

RATIONALE Low-attenuation areas assessed by computed tomography reflect the extent of pathological emphysema and correlate with airflow limitation and mortality in patients with chronic obstructive pulmonary disease. The cumulative size distribution of low-attenuation area clusters follows a power law characterized by an exponent, D. The values of D reflect the complexity of the terminal airspace geometry and sensitively detect alveolar structural changes. Exacerbations of chronic obstructive pulmonary disease have a negative impact on lung function and prognosis. However, the impact on emphysema progression remains unclear. OBJECTIVES We investigated the relationship between exacerbation and emphysema progression assessed by computed tomography in patients with chronic obstructive pulmonary disease. METHODS Exacerbations were prospectively recorded for 2 years. Annual changes in computed tomography parameters of emphysema were compared between patients with and without a history of exacerbations. MEASUREMENTS AND MAIN RESULTS In patients with exacerbations, increases in the percentage of low-attenuation areas and decreases in D were greater than in patients without exacerbations. To interpret these results, we established a novel simulation model and found that not only enlargement of preexisting low-attenuation areas but also coalescence of adjoining low-attenuation areas due to alveolar wall destruction caused emphysema progression in patients with exacerbations. CONCLUSIONS This is the first longitudinal study to demonstrate that exacerbations are involved in emphysema progression in patients with chronic obstructive pulmonary disease. Emphysema progression should be evaluated as part of the outcomes of exacerbations in the management of chronic obstructive pulmonary disease.

Relationship between small airway function and health status, dyspnea and disease control in asthma.

Background: Small airways play important roles in the pathophysiology of asthma. However, relationships between small airway involvement and health status and dyspnea have not been investigated. Objectives: It was the aim of this study to assess the relationships between proximal and peripheral airway functions and health status, dyspnea and disease control in patients with asthma, using impulse oscillometry (IOS). Methods: We performed IOS, spirometry and assessment of health status (Asthma Quality of Life Questionnaire and St. George’s Respiratory Questionnaire), dyspnea (Baseline Dyspnea Index) and disease control (Asthma Control Questionnaire) in 65 asthmatics and evaluated their relationships. Results: Peripheral airway function as evaluated by IOS [R5–R20 (the fall in resistance from 5 to 20 Hz) and X5 (reactance at 5 Hz)], in addition to the proximal airway index (R20), significantly correlated with health status, dyspnea and disease control. Multiple regression analyses revealed that peripheral airway function significantly contributes to these, independently of the proximal airway index. In contrast, forced expiratory volume in 1 s did not significantly contribute to health status or dyspnea. Conclusions: IOS correlated better with clinical symptoms and asthma control than spirometry in patients with asthma. Peripheral and proximal airway functions as assessed separately by IOS independently contribute to health status, dyspnea and disease control, indicating that peripheral airways also represent an important therapeutic target.

Cyclooxygenase-2/Prostaglandin D2/CRTH2 Pathway Mediates Double-Stranded RNA-Induced Enhancement of Allergic Airway Inflammation

Respiratory RNA viruses responsible for the common cold often worsen airway inflammation and bronchial responsiveness, two characteristic features of human asthma. We studied the effects of dsRNA, a nucleotide synthesized during viral replication, on airway inflammation and bronchial hyperresponsiveness in murine models of asthma. Intratracheal instillation of poly I:C, a synthetic dsRNA, increased the airway eosinophilia and enhanced bronchial hyperresponsiveness to methacholine in OVA-sensitized, exposed rats. These changes were associated with induction of cyclooxygenase-2 (COX-2) expression and COX-2-dependent PGD2 synthesis in the lungs, particularly in alveolar macrophages. The direct intratracheal instillation of PGD2 enhanced the eosinophilic inflammation in OVA-exposed animals, whereas pretreatment with a dual antagonist against the PGD2 receptor-(CRTH2) and the thromboxane A2 receptor, but not with a thromboxane A2 receptor-specific antagonist, nearly completely eliminated the dsRNA-induced worsening of airway inflammation and bronchial hyperresponsiveness. CRTH2-deficient mice had the same degree of allergen-induced airway eosinophilia as wild-type mice, but they did not exhibit a dsRNA-induced increase in eosinophil accumulation. Our data demonstrate that COX-2-dependent production of PGD2 followed by eosinophil recruitment into the airways via a CRTH2 receptor are the major pathogenetic factors responsible for the dsRNA-induced enhancement of airway inflammation and responsiveness.

Dysregulated synthesis of protectin D1 in eosinophils from patients with severe asthma

BACKGROUND Protectin D1 (PD1) is an anti-inflammatory and proresolving lipid mediator biosynthesized from the omega-3 fatty acid docosahexaenoic acid (DHA). Exogenous PD1 conferred protection against eosinophilic inflammation in animals with experimental asthma, although its endogenous cellular source and functions in human airways are of interest. OBJECTIVE We sought to investigate the synthesizing capacity of PD1 in eosinophils from healthy subjects and patients with severe asthma and its direct effects on eosinophil functions. METHODS Human eosinophil-derived metabolites of arachidonic acid and DHA were analyzed with liquid chromatography-tandem mass spectrometry-based lipidomic analysis. The biological activities of PD1 on the function of human eosinophils, including chemotaxis, adhesion molecule expressions, degranulation, superoxide anion generation, or survival, were examined. RESULTS We identified PD1 as one of the main anti-inflammatory and proresolving molecules synthesized in human eosinophils. PD1, in nanomolar concentrations, suppressed the chemotaxis induced by CCL11/eotaxin-1 or 5-oxo-eicosatetraenoic acid and modulated the expression of the adhesion molecules CD11b and L-selectin, although it had no effects on the degranulation, superoxide anion generation, or survival of the eosinophils. Compared with the cells harvested from healthy subjects, we observed a prominent decrease in the biosynthesis of PD1 by eosinophils from patients with severe asthma, even in presence of DHA. CONCLUSION These observations are a first indication that activated human eosinophils represent a major source of PD1, which can act as a self-resolving machinery in eosinophilic inflammation, whereas the production of PD1 is impaired in patients with severe asthma.

TLR3-Mediated Synthesis and Release of Eotaxin-1/CCL11 from Human Bronchial Smooth Muscle Cells Stimulated with Double-Stranded RNA

Respiratory infections with RNA viruses, such as rhinovirus or respiratory syncytial virus, are a major cause of asthma exacerbation, accompanied by enhanced neutrophilic and/or eosinophilic inflammation of the airways. We studied the effects of dsRNA synthesized during RNA virus replication, and of its receptor, TLR3, on the synthesis of eosinophilic chemokines in bronchial smooth muscle cells (BSMC). Synthetic dsRNA, polyinosinic-cystidic acid (poly(I:C)), induced the synthesis of eosinophilic chemokines, eotaxin-1/CCL11 and RANTES/CCL5, from primary cultures of human BSMC, and IL-4 increased synergistically the synthesis of poly(I:C)-induced CCL11. A robust eosinophil chemotactic activity was released from BSMC stimulated with poly(I:C) and IL-4, which was mostly inhibited by preincubation with an anti-CCL11, but not with an anti-CCL5 Ab. Although the immunoreactivity of TLR3 was detectable on the cellular surface of BSMC by flow cytometric analysis, pretreatment with an anti-TLR3-neutralizing Ab failed to block the poly(I:C)-induced synthesis of CCL11. We have determined by confocal laser-scanning microscopy that the immunoreactivity of TLR3 was aggregated intracellularly in poly(I:C)-stimulated BSMC, colocalizing with fluorescein-labeled poly(I:C). The synthesis of CCL11 was prominently inhibited by the transfection of TLR3-specific small interfering RNA or by bafilomycin A1, an endosomal acidification inhibitor, further supporting the essential role played by intracellular TLR3 in the synthesis of poly(I:C)-induced CCL11 in BSMC. In conclusion, these observations suggest that, by activating intracellular TLR3 in BSMC, respiratory RNA virus infections stimulate the production of CCL11 and enhance eosinophilic inflammation of the airways in the Th2-dominant microenvironment.

Repeated Instruction on Inhalation Technique Improves Adherence to the Therapeutic Regimen in Asthma

Background: Adherence to inhalation therapy is a critical determinant of the success of asthma management. Reasons for nonadherence have been well studied, but reasons for good adherence are poorly understood. Understanding the mechanisms of adherence to inhalation therapy is important in developing strategies to promote adherence. The objective of this study was to assess the factors and mechanisms that contribute to and the clinical outcomes relating to adherence to inhalation therapy. Methods: The factors and outcomes related to adherence to inhalation therapy were examined cross-sectionally in 176 adults with asthma using a self-reported adherence questionnaire that consisted of four items dealing with the use of inhaled controller medications. A 5-point Likert scale was used for the responses to each item. Adherence was assessed based on the overall mean adherence score. Results: Of the 176 patients who were potential participants, 146 (83%) responded with usable information. Significant factors associated with the overall mean adherence score were older age (r = .18, p = .032) and receiving repeated instruction on inhalation techniques (p = .0016). Of the 146 respondents, 25 (17.1%) patients were given repeated verbal instruction or demonstrations of inhalation technique by a respiratory physician. On logistic regression analysis, good adherence to inhalation therapy was significantly related to the receiving of repeated instruction on inhalation technique, with an odds ratio of 2.90 (95% confidence interval 1.07–7.88; p = .037). Furthermore, less intentional nonadherent behavior was reported in patients with repeated instruction on inhalation technique compared to those without it. A significant correlation was found between the overall mean adherence score and the frequency of asthma exacerbations (r = −.19, p = .021), emergency room visits (r = −.19, p = .042), and the health-related quality of life score (St. Georges Respiratory Questionnaire: Total, r = −.22, p = .024; Symptoms, r = −.21, p = .022; Impacts, r = −.20, p = .035). Conclusions: Repeated instruction on inhalation techniques may contribute to adherence to inhalation therapy through decreasing intentional nonadherence. Furthermore, good adherence to the therapeutic regimen may offer good asthma-related outcomes.

Relationships between repeated instruction on inhalation therapy, medication adherence, and health status in chronic obstructive pulmonary disease

Purpose Adherence to inhalation therapy is a critical determinant of the success of chronic obstructive pulmonary disease (COPD) management. However, in practice, nonadherence to inhalation therapy is very common in COPD patients. The effects of adherence to inhalation therapy in COPD have not been fully studied, and less is known about the relationship between medication adherence and quality of life in COPD. Our aim is to assess the factors that contribute to adherence to inhalation therapy and examine their correlation with quality of life. Patients and methods A cross-sectional analysis of 88 COPD patients was performed using a self-reported adherence questionnaire with responses on a 5-point Likert scale. Results Of the 88 patients who were potential participants, 55 (63%) responded with usable information. The only significant factor associated with the overall mean adherence score was receiving repeated instruction about inhalation techniques (P = 0.032). Of the 55 respondents, 22 (40.0%) were given repeated verbal instruction and/or demonstrations of inhalation technique by a respiratory physician. Significant correlations were found between the overall mean adherence score and the health-related quality of life score (St George’s Respiratory Questionnaire: total, r = −0.35, P = 0.023; symptoms, r = −0.43, P = 0.002; impacts, r = −0.35, P = 0.011). Furthermore, patients with repeated instruction showed better quality of life scores than those who did not receive instruction (total, P = 0.030; symptoms, P = 0.038; impacts, P = 0.019). Conclusions Repeated instruction for inhalation techniques may contribute to adherence to therapeutic regimens, which relates to better health status in COPD.

Using Exhaled Nitric Oxide and Serum Periostin as a Composite Marker to Identify Severe/Steroid-Insensitive Asthma

At present, exhaled nitric oxide (FENO) is a clinically useful biomarker of eosinophilic airway inflammation (1); its levels increase during exacerbation and decrease with inhaled corticosteroid (ICS) treatment (2). Evidence has demonstrated that high FENO levels (>35 ppb) indicate the presence of a highly reactive phenotype among patients with asthma (3), which is useful for the management of patients. Nonetheless, additional markers are required for better characterization of patients with asthma with elevated FENO (>25 ppb), particularly to identify patients who may have steroid resistance (2). Serum periostin is a biomarker of helper T type 2/eosinophilic airway inflammation in asthma (4, 5) distinct from FENO (6). Periostin is a matricellular protein actively involved in airway remodeling (4, 7, 8), with partial steroid resistance (9), although steroid-sensitive aspects were initially highlighted (10). Indeed, high serum periostin levels are associated with refractory eosinophilic inflammation (5) and accelerated decline in pulmonary function in patients with asthma under ICS treatment (11, 12). Importantly, serum periostin levels are relatively stable and less variable than FENO (5, 6), which is advantageous for long-term monitoring of patients with asthma. Therefore, we hypothesized that high serum periostin could be used as a biomarker to efficiently identify ICS-insensitive patients among patients with elevated FENO. In the present study, we demonstrated the reliability of comeasurement of FENO and serum periostin to identify ICS-insensitive patients; they were defined as those with an accelerated decline in FEV1 of at least 30 ml/year (11) or a risk of asthma exacerbations requiring systemic corticosteroid bursts despite adequate ICS treatments in this study. This is a substudy of the Kinki Hokuriku Airway Disease Conference (KiHAC) study that investigated genobiological factors associated with pulmonary function decline in adults with asthma receiving ICS treatment; the patients had undergone 16.26 13.9 FEV1 measurements over 8.06 4.5 years (11). The study protocol (UMIN000002414) was approved by the ethics committee of each participating institution. The present study included the patients who agreed to FENO measurements with a chemiluminescence analyzer (NOA 280; Sievers, Boulder, CO) at enrollment. All patients underwent baseline examination, including a selfcompleted questionnaire, the asthma control test, spirometry, and blood tests at enrollment, as described previously (11). FENO levels were determined at an expiratory flow rate of 50 ml/second, according to the present guidelines (13, 14). The frequency of asthma exacerbation, requiring systemic corticosteroid bursts, was documented for 2 years after enrollment, except for one patient who was lost to follow-up 1 year after enrollment. Serum periostin levels were determined using an enzyme-linked immunosorbent assay at Shino-Test (Kanagawa, Japan), and a cutoff point of 95 ng/ml was used to define high serum periostin (11). Follow-up FENO and serum periostin measurements were not obligatory, but they were measured in several patients on various occasions during the subsequent 2 years (see the online supplement). Statistical analysis was performed with JMP version 9.0 software (SAS Institute Inc., Tokyo, Japan). FENO and serum periostin levels were log-transformed to achieve normal distribution. Pearson correlation coefficients were used to identify relationships between the parameters. Two data sets were compared, using the unpaired t test or Wilcoxon rank-sum test for numerical data and the x test or Fisher exact test for nominal data, as deemed appropriate. The comparison between high and low serum periostin groups or FENO groups regarding an accelerated decline in FEV1 was performed after adjustment for sex, height, age at enrollment, and FEV1 at the first measurement. Logistic regression analysis was performed to estimate the risk of subsequent asthma exacerbations (see the online supplement). Data are presented as means6 SD or percentage. P< 0.05 was considered statistically significant. The FENO levels, determined in 121 patients, were weakly associated with serum periostin levels (Figure 1). This relationship between FENO and serum periostin was stronger when the analysis was confined to patients undergoing treatment step 4 or 5 as

Role of Prostaglandin D2 and Its Receptors in the Pathophysiology of Asthma

Prostaglandin D(2) (PGD(2)) is one of the most abundant lipid mediators present in the airways of asthmatics. However, little was known of the role it plays in the pathophysiology of asthma, until the identification of DP (DP1, PTGDR) and CRTH2 (DP2), two PGD(2)-specific transmembrane receptors with different distribution and intracellular signaling. Pharmacological tools, such as receptor-specific agonists and antagonists, and genetically-engineered mice, which lack either DP or CRTH2, have helped understand the complex effects of PGD(2) in allergic inflammation of the airways. Furthermore, genetic association studies have shown a positive linkage of the genetic polymorphisms in DP and CRTH2, with asthma phenotypes from specific ethnic backgrounds, further highlighting the importance of PGD(2) and its receptors in the pathophysiology of asthma.