Applicable predictive factors extracted from peak flow trajectory for the prediction of asthma exacerbation

BACKGROUND

Real-time asthma exacerbation prediction and acute asthma attack detection are essential for patients with severe asthma. Peak expiratory flow (PEF) exhibits a potential for use in long-term asthma self-monitoring. However, the method for processing PEF calculations remains to be clarified.

OBJECTIVE

To develop clinically applicable novel exacerbation predictors calculated using PEF records.

METHODS

Previously proposed exacerbation predictors, including the slope of PEF, percentage predicted PEF, percentage best PEF, the highest PEF over the lowest PEF within specific periods, and PEF coefficient of variation, in addition to a novel indicator delta PEF moving average (ΔMA), defined as the difference between 14-day and 3-day average PEF values, along with moving average (MA) adjusted for PEF reference (%ΔMA), were verified using the Hokkaido-based Investigative Cohort Analysis for Refractory Asthma data of 127 patients with severe asthma from whom 73,503 PEF observations were obtained. Receiver operating characteristic curves for all predictors were drawn, and the corresponding areas under the curve (AUCs) were computed. Regression analysis for MA and percentage MA were conducted.

RESULTS

The most outstanding performance was shown by ΔMA and %ΔMA, with AUC values of 0.659 and 0.665 in the univariate model, respectively. When multivariate models were incorporated with random intercepts for individual participants, the AUC for ΔMA and %ΔMA increased to 0.907 and 0.919, respectively.

CONCLUSION

The MA and percentage MA are valuable indicators that should be considered when deriving predictors from the PEF trajectory for monitoring exacerbations in patients with severe asthma.

TRIAL REGISTRATION

The Hokkaido-based Investigative Cohort Analysis for Refractory Asthma was registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN ID: 000003254). https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000003917.

Apoptosis inhibitor of macrophage (AIM)/CD5L is involved in the pathogenesis of COPD

BACKGROUND

Alveolar macrophages (AMs) and AM-produced matrix metalloprotease (MMP)-12 are known to play critical roles in the pathogenesis of chronic obstructive pulmonary disease (COPD). The apoptosis inhibitor of the macrophages (AIM)/CD5 molecule-like (CD5L) is a multifunctional protein secreted by the macrophages that mainly exists in the blood in a combined form with the immunoglobulin (Ig)M pentamer. Although AIM has both facilitative and suppressive roles in various diseases, its role in COPD remains unclear.

METHODS

We investigated the role of AIM in COPD pathogenesis using porcine pancreas elastase (PPE)-induced and cigarette smoke-induced emphysema mouse models and an in vitro model using AMs. We also analyzed the differences in the blood AIM/IgM ratio among nonsmokers, healthy smokers, and patients with COPD and investigated the association between the blood AIM/IgM ratio and COPD exacerbations and mortality in patients with COPD.

RESULTS

Emphysema formation, inflammation, and cell death in the lungs were attenuated in AIM-/- mice compared with wild-type (WT) mice in both PPE- and cigarette smoke-induced emphysema models. The PPE-induced increase in MMP-12 was attenuated in AIM-/- mice at both the mRNA and protein levels. According to in vitro experiments using AMs stimulated with cigarette smoke extract, the MMP-12 level was decreased in AIM-/- mice compared with WT mice. This decrease was reversed by the addition of recombinant AIM. Furthermore, an analysis of clinical samples showed that patients with COPD had a higher blood AIM/IgM ratio than healthy smokers. Additionally, the blood AIM/IgM ratio was positively associated with disease severity in patients with COPD. A higher AIM/IgM ratio was also associated with a shorter time to the first COPD exacerbation and higher all-cause and respiratory mortality.

CONCLUSIONS

AIM facilitates the development of COPD by upregulating MMP-12. Additionally, a higher blood AIM/IgM ratio was associated with poor prognosis in patients with COPD.

TRIAL REGISTRATION

This clinical study, which included nonsmokers, healthy smokers, and smokers with COPD, was approved by the Ethics Committee of the Hokkaido University Hospital (012-0075, date of registration: September 5, 2012). The Hokkaido COPD cohort study was approved by the Ethics Committee of the Hokkaido University School of Medicine (med02-001, date of registration: December 25, 2002).

Stronger Associations of Centrilobular Than Paraseptal Emphysema With Longitudinal Changes in Diffusing Capacity and Mortality in COPD

BACKGROUND

The factors associated with longitudinal changes in diffusing capacity remain unclear among patients with COPD. Centrilobular emphysema (CLE) and paraseptal emphysema (PSE) are major emphysema subtypes that may have distinct clinical-physiological impacts in these patients.

RESEARCH QUESTION

Are CLE and PSE differently associated with longitudinal changes in diffusing capacity and mortality in patients with COPD?

STUDY DESIGN AND METHODS

This pooled analysis included 399 patients with COPD from two prospective observational COPD cohorts. CLE and PSE were visually assessed on CT scan according to the Fleischner Society statement. The diffusing capacity and transfer coefficient of the lung for carbon monoxide (Dlco and KCO) and FEV1 were evaluated at least annually over a 5-year period. Mortality was recorded over 10 years. Longitudinal changes in FEV1, Dlco, and KCO and mortality were compared between mild or less severe and moderate or more severe CLE and between present and absent PSE in each Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage.

RESULTS

The Dlco and KCO decline was weakly associated with FEV1 and greater in GOLD stage 3 or higher than in GOLD stages 1 and 2. Furthermore, moderate or more severe CLE, but not present PSE, was associated with steeper declines in Dlco for GOLD stages 1 and 3 or higher and KCO for all GOLD stages independent of age, sex, height, and smoking history. The moderate or more severe CLE, but not present PSE, was associated with additional FEV1 decline and higher 10-year mortality among patients with GOLD stage 3 or higher.

INTERPRETATION

A CT scan finding of moderate or more severe CLE, but not PSE, was associated with a subsequent accelerated impairment in diffusing capacity and higher long-term mortality in severe GOLD stage among patients with COPD.

Clinical characteristics and natural course of chronic obstructive pulmonary disease and/or asthma in Japanese patients: a summary report of two Hokkaido-based cohort studies

Chronic obstructive pulmonary disease (COPD) and asthma are the most common chronic airway diseases and are characterized by chronic airway inflammation and airflow limitation. Japanese patients with COPD or asthma have characteristics different from those of Westerners. Therefore, understanding the characteristics and clinical course of Japanese patients with COPD and those with asthma, particularly severe asthma, is critical for their management and appropriate treatment. The Hokkaido COPD cohort and Hokkaido-based Investigative Cohort Analysis for Refractory Asthma (Hi-CARAT) are high-quality cohort studies of COPD and asthma in the Japanese population and provide valuable data. This report summarizes the clinical findings from the two cohort studies and provides data for more appropriate management of Japanese patients with COPD and/or asthma. Overall, 279 patients with COPD were followed up for up to 10 years in the Hokkaido COPD cohort study, and 127 with severe asthma were followed up for up to 6 years in the Hi-CARAT study. Seventy-nine patients with mild-to-moderate asthma provided baseline data for the Hi-CARAT study. In each disease, several distinct factors, including systemic status and non-pulmonary factors, were associated with important clinical outcomes, such as lung function decline, exacerbations, impaired quality of life, and mortality. Therefore, multifaceted evaluation based on the characteristics of the Japanese population is necessary for the management of COPD and asthma.

Subtyping emphysematous COPD by respiratory volume change distributions on CT

BACKGROUND

There is considerable heterogeneity among patients with emphysematous chronic obstructive pulmonary disease (COPD). We hypothesised that in addition to emphysema severity, ventilation distribution in emphysematous regions would be associated with clinical-physiological impairments in these patients.

OBJECTIVE

To evaluate whether the discordance between respiratory volume change distributions (from expiration to inspiration) in emphysematous and non-emphysematous regions affects COPD outcomes using two cohorts.

METHODS

Emphysema was quantified using a low attenuation volume percentage on inspiratory CT (iLAV%). Local respiratory volume changes were calculated using non-rigidly registered expiratory/inspiratory CT. The Ventilation Discordance Index (VDI) represented the log-transformed Wasserstein distance quantifying discordance between respiratory volume change distributions in emphysematous and non-emphysematous regions.

RESULTS

Patients with COPD in the first cohort (n=221) were classified into minimal emphysema (iLAV% <10%; n=113) and established emphysema with high VDI and low VDI groups (n=46 and 62, respectively). Forced expiratory volume in 1 s (FEV₁) was lower in the low VDI group than in the other groups, with no difference between the high VDI and minimal emphysema groups. Higher iLAV%, more severe airway disease and hyperventilated emphysematous regions in the upper-middle lobes were independently associated with lower VDI. The second cohort analyses (n=93) confirmed these findings and showed greater annual FEV₁ decline and higher mortality in the low VDI group than in the high VDI group independent of iLAV% and airway disease on CT.

CONCLUSION

Lower VDI is associated with severe airflow limitation and higher mortality independent of emphysema severity and airway morphological changes in patients with emphysematous COPD.

Relationships of computed tomography-based small vessel indices of the lungs with ventilation heterogeneity and high transfer coefficients in non-smokers with asthma

Background: The mechanism of high transfer coefficients of the lungs for carbon monoxide (Kco) in non-smokers with asthma is explained by the redistribution of blood flow to the area with preserved ventilation, to match the ventilation perfusion. Objectives: To examine whether ventilation heterogeneity, assessed by pulmonary function tests, is associated with computed tomography (CT)-based vascular indices and Kco in patients with asthma. Methods: Participants were enrolled from the Hokkaido-based Investigative Cohort Analysis for Refractory Asthma (Hi-CARAT) study that included a prospective asthmatic cohort. Pulmonary function tests including Kco, using single breath methods; total lung capacity (TLC), using multiple breath methods; and CT, were performed on the same day. The ratio of the lung volume assessed using single breath methods (alveolar volume; V_A) to that using multiple breath methods (TLC) was calculated as an index of ventilation heterogeneity. The volume of the pulmonary small vessels <5 mm² in the whole lung (BV5 volume), and number of BV5 at a theoretical surface area of the lungs from the plural surface (BV5 number) were evaluated using chest CT images. Results: The low V_A/TLC group (the lowest quartile) had significantly lower BV5 number, BV5 volume, higher BV5 volume/BV5 number, and higher Kco compared to the high V_A/TLC group (the highest quartile) in 117 non-smokers, but not in 67 smokers. Multivariable analysis showed that low V_A/TLC was associated with low BV5 number, after adjusting for age, sex, weight, lung volume on CT, and CT emphysema index in non-smokers (not in smokers). Conclusion: Ventilation heterogeneity may be associated with low BV5 number and high Kco in non-smokers (not in smokers). Future studies need to determine the dynamic regional system in ventilation, perfusion, and diffusion in asthma.

Blood eosinophil count variability in chronic obstructive pulmonary disease and severe asthma

BACKGROUND

Blood eosinophils are essential biomarkers that vary substantially over time in patients with COPD and asthma. However, no study has identified the changes and effects in the changes of the blood eosinophil counts over time in both diseases. This study aimed to demonstrate blood eosinophil variability in patients with COPD and severe asthma based on these backgrounds.

METHODS

A total of 172 patients with COPD from the Hokkaido COPD cohort study and 96 patients with severe asthma from the Hokkaido Severe Asthma Cohort Study, whose blood eosinophil counts were measured annually over a 3-year period, were analyzed. The factors contributing to consistently high or low blood eosinophil counts were examined in each cohort. The stability of the eosinophil classification (<150, 150-299, ≥300 cells/μL) was compared based on the number of asthma-like features in patients with COPD and the smoking status in patients with severe asthma.

RESULTS

Among all the patients, the most stable range of baseline blood eosinophil counts differed between the two diseases, with <150 cells/μL in COPD and ≥300 cells/μL in severe asthma. In COPD, the number of asthma-like features (bronchodilator reversibility, blood eosinophilia, and atopy) affects the blood eosinophil count variation patterns. In severe asthma, smoking status did not affect the blood eosinophil count variation patterns.

CONCLUSIONS

We identified variations in the blood eosinophil counts and their contributing factors in patients with COPD and severe asthma.

Differential role of mucus plugs in asthma: Effects of smoking and association with airway inflammation

BACKGROUND

The physiological importance of mucus plugs in computed tomography (CT) imaging is being increasingly recognized. However, whether airway inflammation and smoking affect the association between mucus plugs and clinical-physiological outcomes in asthma remains to be elucidated. The objective of this study is to examine how airway inflammation and/or smoking affect the correlation of CT-based mucus plug scores with exacerbation frequency and airflow limitation indices in asthma.

METHODS

A total of 168 patients with asthma who underwent chest CT and sputum evaluation were enrolled and classified in eosinophilic asthma (EA; n = 103) and non-eosinophilic asthma (NEA; n = 65) groups based on sputum eosinophil percentage (cut-off: 3%). The mucus plug score was defined as the number of lung segments with mucus plugs seen on CT.

RESULTS

More mucus plugs were detected on CT scans in the EA group than in the NEA group, regardless of smoking status. Mucus plug score and exacerbation frequency during one year after enrollment were significantly associated in the EA group but not in the NEA group after adjusting for demographics, blood eosinophil count, and fractional exhaled nitric oxide. Mucus plug score was associated with percentage of predicted forced expiratory volume in 1 s in non-smoking individuals in the EA and NEA group and in smoking individuals in the EA group but not in the NEA group after adjusting for demographics.

CONCLUSIONS

The association of mucus plug score with exacerbation frequency and reduced lung function may vary due to airway inflammatory profile and smoking status in asthma.

Association of longitudinal changes in quality of life with comorbidities and exacerbations in patients with severe asthma

BACKGROUND

Quality of life (QoL) assessment is important in the management of severe asthma, and comorbidities and/or exacerbations may affect longitudinal QoL. However, there are few reports on the longitudinal assessment of QoL in patients with asthma over multiple years and its related factors. This study aimed to clarify the relationship of longitudinal changes in QoL with comorbidities and/or exacerbations during a prolonged observation period in patients with severe asthma.

METHODS

A total of 105 subjects who participated in the Hokkaido-based Investigative Cohort Analysis for Refractory Asthma (Hi-CARAT) with a six-year follow-up were analyzed. QoL was assessed annually, using the Standardized Asthma Quality of Life Questionnaire, and the subjects were divided into three groups: (1) persistently good QoL, (2) persistently poor QoL, and (3) fluctuating QoL. Assessed comorbidities comprised depression, gastroesophageal reflux disease, and excessive daytime sleepiness (EDS), a key symptom of obstructive sleep apnea.

RESULTS

Of 105 subjects with severe asthma, 53 (50%) were classified in the persistently good QoL group, 10 (10%) in the persistently poor QoL group, and 42 (40%) in the fluctuating QoL group. The persistently poor QoL group was associated with shorter time to hospitalization due to exacerbation and the presence of multiple comorbidities. In addition, the presence of EDS was an independent contributor to the fluctuating QoL group compared to the persistently good QoL group.

CONCLUSIONS

The presence of multiple comorbidities and hospitalization due to exacerbation contribute to longitudinal changes in QoL in patients with severe asthma.

Further evidence for association of YKL-40 with severe asthma airway remodeling

BACKGROUND

The chitinase-like protein YKL-40 is associated with airflow limitation on spirometry and airway remodeling in patients with asthma. It remains unclear whether YKL-40 is associated with morphologic changes in the airways and parenchyma or with future progression of airflow limitation in severe asthma.

OBJECTIVE

To evaluate the association of circulating YKL-40 levels with morphologic changes in the airways and parenchyma and with longitudinal progression of airflow limitation.

METHODS

The patients were participants in the Hokkaido Severe Asthma Cohort Study (n = 127), including smokers. This study consisted of 2 parts. In analysis 1, we analyzed associations between circulating YKL-40 levels and several asthma-related indices, including computed tomography-derived indices of proximal wall area percentage, the complexity of the airways (airway fractal dimension), and the parenchyma (exponent D) cross-sectionally (n = 97). In analysis 2, we evaluated the impact of circulating YKL-40 levels on forced expiratory volume in 1 second (FEV₁) decline longitudinally for a 5-year follow-up (n = 103).

RESULTS

Circulating YKL-40 levels were significantly associated with proximal wall area percentage and airway fractal dimension (r = 0.25, P = .01; r = -0.22, P = .04, respectively), but not with exponent D. The mean annual change in FEV₁ was -33.7 (± 23.3) mL/y, and the circulating YKL-40 level was a significant independent factor associated with annual FEV₁ decline (β = -0.24, P = .02), even after controlling for exponent D (β = -0.26, P = .01).

CONCLUSION

These results provide further evidence for the association of YKL-40 with the pathogenesis of airway remodeling in severe asthma.

Annual Body Weight Change and Prognosis in Chronic Obstructive Pulmonary Disease

Purpose

Low body mass index (BMI) has been reported to be associated with poor prognosis in patients with chronic obstructive pulmonary disease (COPD). In contrast, a detailed analysis of the association between body weight change over time and prognosis is not sufficient, particularly in Japanese patients with COPD who have been reported to be much thinner compared to Westerners. This study aimed to investigate the relationship between annual body weight change and long-term prognosis in Japanese patients with COPD in two independent cohorts.

Patients and Methods

We analyzed 279 patients with COPD who participated in the Hokkaido COPD cohort study as a discovery cohort. We divided participants into three groups according to quartiles of annual body weight change calculated by the data from the first 5 years: weight loss group (<-0.17 kg/year), no change group (−0.17 to ≤0.20 kg/year), and weight gain group (>0.20 kg/year). The association between annual body weight change and prognosis was replicated in the Kyoto University cohort (n = 247).

Results

In the Hokkaido COPD cohort study, the weight loss group had significantly worse mortality than the other groups, whereas there was no difference in BMI at baseline. In the multivariate analysis, annual body weight change was an independent risk factor for all-cause mortality, which was confirmed in the Kyoto University cohort.

Conclusion

Annual body weight loss is associated with poor prognosis in Japanese patients with COPD, independent of baseline BMI. Longitudinal assessment of body weight is important for the management of COPD.

Large-scale plasma proteomics can reveal distinct endotypes in chronic obstructive pulmonary disease and severe asthma

BACKGROUND

Chronic airway diseases including chronic obstructive pulmonary disease (COPD) and asthma are heterogenous in nature and endotypes within are underpinned by complex biology. This study aimed to investigate the utility of proteomic profiling of plasma combined with bioinformatic mining, and to define molecular endotypes and expand our knowledge of the underlying biology in chronic respiratory diseases.

METHODS

The plasma proteome was evaluated using an aptamer-based affinity proteomics platform (SOMAscan®), representing 1238 proteins in 34 subjects with stable COPD and 51 subjects with stable but severe asthma. For each disease, we evaluated a range of clinical/demographic characteristics including bronchodilator reversibility, blood eosinophilia levels, and smoking history. We applied modified bioinformatic approaches used in the evaluation of RNA transcriptomics.

RESULTS

Subjects with COPD and severe asthma were distinguished from each other by 365 different protein abundancies, with differential pathway networks and upstream modulators. Furthermore, molecular endotypes within each disease could be defined. The protein groups that defined these endotypes had both known and novel biology including groups significantly enriched in exosomal markers derived from immune/inflammatory cells. Finally, we observed associations to clinical characteristics that previously have been under-explored.

CONCLUSION

This investigational study evaluating the plasma proteome in clinically-phenotyped subjects with chronic airway diseases provides support that such a method can be used to define molecular endotypes and pathobiological mechanisms that underpins these endotypes. It provided new concepts about the complexity of molecular pathways that define these diseases. In the longer term, such information will help to refine treatment options for defined groups.

One-Year In Situ Incubation of Pyrite at the Deep Seafloor and Its Microbiological and Biogeochemical Characterizations

In this study, we performed a year-long in situ incubation experiment on a common ferrous sulfide (Fe-S) mineral, pyrite, at the oxidative deep seafloor in the hydrothermal vent field in the Izu-Bonin arc, Japan, and characterized its microbiological and biogeochemical properties to understand the microbial alteration processes of the pyrite, focusing on Fe(II) oxidation. The microbial community analysis of the incubated pyrite showed that the domain Bacteria heavily dominated over Archaea compared with that of the ambient seawater, and Alphaproteobacteria and Gammaproteobacteria distinctively codominated at the class level. The mineralogical characterization by surface-sensitive Fe X-ray absorption near-edge structure (XANES) analysis revealed that specific Fe(III) hydroxides (schwertmannite and ferrihydrite) were locally formed at the pyrite surface as the pyrite alteration products. Based on the Fe(III) hydroxide species and proportion, we thermodynamically calculated the pH value at the pyrite surface to be pH 4.9 to 5.7, indicating that the acidic condition derived from pyrite alteration was locally formed at the surface against neutral ambient seawater. This acidic microenvironment at the pyrite surface might explain the distinct microbial communities found in our pyrite samples. Also, the acidity at the pyrite surface indicates that the abiotic Fe(II) oxidation rate was much limited at the pyrite surface kinetically, 3.9 × 103- to 1.6 × 105-fold lower than that in the ambient seawater. Moreover, nanoscale characterization of microbial biomolecules using carbon near-edge X-ray absorption fine-structure (NEXAFS) analysis showed that the sessile cells attached to pyrite excreted the acidic polysaccharide-rich extracellular polymeric substances at the pyrite surface, which can lead to the promotion of biogenic Fe(II) oxidation and pyrite alteration. IMPORTANCE Pyrite is one of the most common Fe-S minerals found in submarine hydrothermal environments. Previous studies demonstrated that the Fe-S mineral can be a suitable host for Fe(II)-oxidizing microbes in hydrothermal environments; however, the details of microbial Fe(II) oxidation processes with Fe-S mineral alteration are not well known. The spectroscopic and thermodynamic examination in the present study suggests that a moderately acidic pH condition was locally formed at the pyrite surface during pyrite alteration at the seafloor due to proton releases with Fe(II) and sulfidic S oxidations. Following previous studies, the abiotic Fe(II) oxidation rate significantly decreases with a decrease in pH, but the biotic (microbial) Fe(II) oxidation rate is not sensitive to the pH decrease. Thus, our findings clearly suggest that the pyrite surface is a unique microenvironment where abiotic Fe(II) oxidation is limited and biotic Fe(II) oxidation is more prominent than that in neutral ambient seawater.

Parenchymal destruction in asthma: Fixed airflow obstruction and lung function trajectory

BACKGROUND

Fixed airflow obstruction (FAO) in asthma, particularly in nonsmokers, is generally believed to be caused by airway remodeling. However, parenchymal destruction may also contribute to FAO and longitudinal decline in forced expiratory volume in 1 second (FEV₁).

OBJECTIVES

To evaluate parenchymal destruction, we used emphysema indices, exponent D, and low-attenuation area percentage (LAA%) on computed tomography (CT), and test whether the parenchymal destruction and airway disease are independently associated with FAO and FEV₁ decline in both smoking and nonsmoking asthma.

METHODS

Exponent D, LAA%, wall area percentage at segmental airways, and airway fractal dimension (AFD) in those with asthma were measured on inspiratory CT and compared to those in patients with chronic obstructive pulmonary disease (COPD).

RESULTS

Exponent D was lower and LAA% was higher in COPD (n = 42) and asthma with FAO (n = 101) than in asthma without FAO (n = 88). The decreased exponent D and increased LAA% were associated with FAO regardless of smoking status or asthma severity. In multivariable analysis, decreased exponent D and increased LAA% were associated with an increased odds ratio of FAO and decreased FEV₁, irrespective of wall area percentage and airway fractal dimension. Moreover, decreased exponent D affected the longitudinal decline in FEV₁ in those with severe asthma, independent of smoking status.

CONCLUSIONS

Patients with asthma with FAO showed parenchymal destruction regardless of smoking status and asthma severity. Parenchymal destruction was associated with an accelerated FEV₁ decline, suggesting the involvements of both airway and parenchyma in the pathophysiology of a subgroup of asthma.

Combined assessment of pulmonary arterial enlargement and coronary calcification predicts the prognosis of patients with chronic obstructive pulmonary disease

INTRODUCTION

In chronic obstructive pulmonary disease (COPD), chest computed tomography (CT) provides clinically important cardiovascular findings, which include diameter of pulmonary artery (PA), its ratio to the diameter of the aorta (PA:A ratio), and coronary artery calcium score (CACS). The clinical importance of these cardiovascular findings has not been fully assessed in Japan, where cardiovascular morbidity and/or mortality is reported to be much less compared with Western counterparts.

METHODS

PA diameter and PA:A ratio were measured in 172 and 130 patients with COPD who enrolled in the Hokkaido COPD cohort study and the Kyoto University cohort, respectively. CACS was measured in 131 and 128 patients in each cohort.

RESULTS

While the highest quartile group in PA diameter was associated with higher all-cause mortality compared to the lowest quartile group in both cohorts, individual assessments of PA:A ratio and CACS were not associated with the long-term clinical outcomes. When PA diameter and CACS were combined, patients with PA enlargement (diameter >29.5 mm) and/or coronary calcification (score >440.8) were associated with higher all-cause mortality in both cohorts.

CONCLUSION

Combined assessment of PA enlargement and CACS was associated with poor prognosis, which provides a clinical advantage in management of patients with COPD even in geographical regions with lower risk of cardiovascular diseases.

A Comparative Evaluation of Computed Tomography Images for the Classification of Spirometric Severity of the Chronic Obstructive Pulmonary Disease with Deep Learning

Recently, deep learning applications in medical imaging have been widely applied. However, whether it is sufficient to simply input the entire image or whether it is necessary to preprocess the setting of the supervised image has not been sufficiently studied. This study aimed to create a classifier trained with and without preprocessing for the Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification using CT images and to evaluate the classification accuracy of the GOLD classification by confusion matrix. According to former GOLD 0, GOLD 1, GOLD 2, and GOLD 3 or 4, eighty patients were divided into four groups (n = 20). The classification models were created by the transfer learning of the ResNet50 network architecture. The created models were evaluated by confusion matrix and AUC. Moreover, the rearranged confusion matrix for former stages 0 and ≥1 was evaluated by the same procedure. The AUCs of original and threshold images for the four-class analysis were 0.61 ± 0.13 and 0.64 ± 0.10, respectively, and the AUCs for the two classifications of former GOLD 0 and GOLD ≥ 1 were 0.64 ± 0.06 and 0.68 ± 0.12, respectively. In the two-class classification by threshold image, recall and precision were over 0.8 in GOLD ≥ 1, and in the McNemar–Bowker test, there was some symmetry. The results suggest that the preprocessed threshold image can be possibly used as a screening tool for GOLD classification without pulmonary function tests, rather than inputting the normal image into the convolutional neural network (CNN) for CT image learning.

One-year clinically important deterioration and long-term clinical course in Japanese patients with COPD: a multicenter observational cohort study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease with a complex progression of many clinical presentations, and clinically important deterioration (CID) has been proposed in the Western studies as a composite endpoint of disease progression. The aim of this study was to investigate the relationships between 1-year CID and the following long-term clinical outcomes in Japanese patients with COPD who have been reported to have different characteristics compared to the Westerners.

METHODS

Among Japanese patients with COPD enrolled in the Hokkaido COPD cohort study, 259 patients who did not drop out within the first year were analyzed in this study. Two definitions of CID were used. Definition 1 comprised ≥ 100 mL decrease in forced expiratory volume in 1 s (FEV₁), ≥ 4-unit increase in St George's Respiratory Questionnaire (SGRQ) score from baseline, or moderate or severe exacerbation. For Definition 2, the thresholds for the FEV₁ and SGRQ score components were doubled. The presence of CID was evaluated within the first year from enrollment, and analyzed the association of the presence of CID with following 4-year risk of exacerbations and 9-year mortality.

RESULTS

Patients with CID using Definition 1, but not any single CID component, during the first year had a significantly worse mortality compared with those without CID. Patients with CID using Definition 2 showed a similar trend on mortality, and had a shorter exacerbation-free survival compared with those without CID.

CONCLUSIONS

Adoption of CID is a beneficial and useful way for the assessment of long-term disease progression and clinical outcomes even in Japanese population with COPD. The definition of CID might be optimized according to the characteristics of COPD population and the observation period for CID.

Factors for the Variability of Three Acceptable Maximal Expiratory Flow-Volume Curves in Chronic Obstructive Pulmonary Disease

Background

Generally, the maximal expiratory flow–volume (MEFV) curve must be measured for the diagnosis and staging of chronic obstructive pulmonary disease (COPD). As this test is effort dependent, international guidelines recommend that three acceptable trials are required for each test. However, no study has examined the magnitude and factors for the variability in parameters among three acceptable trials.

Methods

We evaluated the intra-individual variations in several parameters among three acceptable MEFV curves obtained at one-time point in patients with COPD (n = 28, stage 1; n = 36, stage 2; n = 21, stages 3–4). Next, the factors for such variations were examined using forced expiratory volume in 1 second (FEV₁) and forced vital capacity (FVC).

Results

The averages of coefficient of variation (CV) for FEV₁ and FVC were 2.0% (range: 1.0–3.0%) and 1.6% (0.9–2.2%), respectively. Both parameters were significantly better than peak expiratory flow rate, forced expiratory flow at 50% of expired FVC, and forced expiratory flow at 75% of expired FVC (CVs: 5.0–6.9%). A higher spirometric stage was significantly associated with higher CVs for FVC and FEV_1, and older age was significantly correlated with a higher variation in FEV₁ alone. Furthermore, a significantly inverse association was observed between emphysema severity, and the CVs for FEV₁, but not that for FVC, regardless of spirometric stage.

Conclusion

Both FVC and FEV₁ are highly reproducible; nevertheless, older age, lower FEV₁ at baseline, and non-emphysema phenotype are factors for a higher variability in FEV₁ in patients with COPD.

Annual Fractional Exhaled Nitric Oxide Measurements and Exacerbations in Severe Asthma

Purpose

Fractional exhaled nitric oxide (FENO) reflects eosinophilic inflammation of the airways. However, the significance of longitudinal assessment of FENO, including its variability, in the clinical course of severe asthma remains unclear. The aim of this study is to examine the association between long-term changes in FENO and the development of exacerbations in severe asthma.

Patients and Methods

Among the severe asthma patients enrolled in the Hokkaido Severe Asthma Cohort Study, 100 patients with severe asthma who completed a 3-year follow-up in which FENO was measured annually were included. According to the FENO level at baseline, 1 year, and 2 years, the patients were classified into three groups: the sustained high group (≥50 ppb at all three visits), the sustained low group (<25 ppb at all three visits), and the intermediate group (other). Subjects in the intermediate group were further classified into two groups based on the median value of the coefficient of variation (CV) of FENO during the 3 years (high CV and low CV intermediate groups).

Results

The sustained high group experienced shorter exacerbation-free survival and more frequent exacerbations than the sustained low group (median number of exacerbation events, 3 vs 0, p = 0.01). In the intermediate group, the high CV group experienced shorter exacerbation-free survival than the low CV group, and the CV of FENO was an independent contributing factor to the development of exacerbations.

Conclusion

Persistence of FENO above 50 ppb over the years as well as the presence of large variations in FENO levels was associated with the development of exacerbations in patients with severe asthma.

Unique Mortality Profile in Japanese Patients with COPD: An Analysis from the Hokkaido COPD Cohort Study

Purpose

Causes of death may be unique and different in Japanese patients with COPD because they are generally older, thinner, experience fewer exacerbations, and live longer than those in other countries. We investigated the detailed mortality profile in the Hokkaido COPD cohort study, which completed a 10-year follow-up with a very low dropout rate.

Patients and Methods

We prospectively examined the 10-year natural history in 279 Japanese patients with COPD (GOLD 1, 26%; GOLD 2, 45%; GOLD 3, 24%; and GOLD 4, 5%). The majority of patients were male, and the average age at baseline was 69 years old. About 95% of all patients had accurate mortality data. The risk factors for mortality were also analyzed.

Results

During the 10 years, 112 patients (40%) died. Their median survival time was 6.1 years (interquartile range: 4.7–7.9 years), and age at death was 79 ± 6 years old (mean ± SD). Respiratory diseases, including pneumonia, were the leading causes of death in 45 (40%), followed by lung cancer in 24 (21%), other cancers in 18 (16%), and cardiovascular diseases in 12 (11%). In particular, lung cancer-related death was equally distributed across all COPD stages, with a higher proportion of lung cancer in the relatively younger generation (<64 years old). Older age at baseline, lower BMI, and severer emphysema were significant risk factors for all-cause mortality.

Conclusion

The unique mortality profile observed in this study should be considered when designing strategies for the management of patients with COPD in any geographic region.

Per cent low attenuation volume and fractal dimension of low attenuation clusters on CT predict different long-term outcomes in COPD

BACKGROUND

Fractal dimension (D) characterises the size distribution of low attenuation clusters on CT and assesses the spatial heterogeneity of emphysema that per cent low attenuation volume (%LAV) cannot detect. This study tested the hypothesis that %LAV and D have different roles in predicting decline in FEV₁, exacerbation and mortality in patients with COPD.

METHODS

Chest inspiratory CT scans in the baseline and longitudinal follow-up records for FEV₁, exacerbation and mortality prospectively collected over 10 years in the Hokkaido COPD Cohort Study were examined (n=96). The associations between CT measures and long-term outcomes were replicated in the Kyoto University cohort (n=130).

RESULTS

In the Hokkaido COPD cohort, higher %LAV, but not D, was associated with a greater decline in FEV₁ and 10-year mortality, whereas lower D, but not %LAV, was associated with shorter time to first exacerbation. Multivariable analysis for the Kyoto University cohort confirmed that lower D at baseline was independently associated with shorter time to first exacerbation and that higher LAV% was independently associated with increased mortality after adjusting for age, height, weight, FEV₁ and smoking status.

CONCLUSION

These well-established cohorts clarify the different prognostic roles of %LAV and D, whereby lower D is associated with a higher risk of exacerbation and higher %LAV is associated with a rapid decline in lung function and long-term mortality. Combination of %LAV and fractal D may identify COPD subgroups at high risk of a poor clinical outcome more sensitively.

Serum Alpha-1 Antitrypsin Levels and the Clinical Course of Chronic Obstructive Pulmonary Disease

Purpose

Alpha-1 antitrypsin deficiency is associated with the development of chronic obstructive pulmonary disease (COPD), whereas increased levels of serum alpha-1antitrypsin occur in response to inflammation. The effects of alpha-1 antitrypsin levels on the clinical course of COPD had been unclear. We investigated the association of serum alpha-1 antitrypsin levels with the clinical course of COPD patients based on data from a 10-year prospective cohort study.

Patients and methods

We analyzed 278 COPD patients who participated in the Hokkaido COPD cohort study and who did not meet the criteria for alpha-1 antitrypsin deficiency. We divided the subjects into 3 groups according to quartiles of serum alpha-1 antitrypsin levels at baseline: lower group (<116 mg/dL, n = 66); middle group (116 to ≤141 mg/dL, n = 145); and higher group (>141 mg/dL, n = 67). The annual change in forced expiratory volume in 1 s (FEV₁) and events of COPD exacerbation were monitored during the first 5 years, and mortality was followed-up during the entire 10 years.

Results

At baseline, the higher group showed lower body mass index; higher computed tomography emphysema score; lower diffusing capacity; higher levels of acute-phase proteins; and higher blood neutrophil counts. Longitudinal analyses revealed that in the higher group, the annual decline in FEV₁ was rapid and the 10-year mortality was higher, but there was no association between serum alpha-1 antitrypsin levels and time to first exacerbation.

Conclusion

COPD subjects with higher serum alpha-1 antitrypsin levels were associated with a worse systemic inflammation status and higher 10-year mortality.

Identification of chronic obstructive pulmonary disease subgroups in 13 Asian cities

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a heterogeneous condition that can differ in its clinical manifestation, structural changes and response to treatment.

OBJECTIVE

To identify subgroups of COPD with distinct phenotypes, evaluate the distribution of phenotypes in four related regions and calculate the 1-year change in lung function and quality of life according to subgroup.

METHODS

Using clinical characteristics, we performed factor analysis and hierarchical cluster analysis in a cohort of 1676 COPD patients from 13 Asian cities. We compared the 1-year change in forced expiratory volume in one second (FEV1), modified Medical Research Council dyspnoea scale score, St George's Respiratory Questionnaire (SGRQ) score and exacerbations according to subgroup derived from cluster analysis.

RESULTS

Factor analysis revealed that body mass index, Charlson comorbidity index, SGRQ total score and FEV1 were principal factors. Using these four factors, cluster analysis identified three distinct subgroups with differing disease severity and symptoms. Among the three subgroups, patients in subgroup 2 (severe disease and more symptoms) had the most frequent exacerbations, most rapid FEV1 decline and greatest decline in SGRQ total score.

CONCLUSION

Three subgroups with differing severities and symptoms were identified in Asian COPD subjects.

Prospective predictors of exacerbation status in severe asthma over a 3-year follow-up

BACKGROUND

A predisposition to exacerbations is being recognized as a distinct phenotype with "previous exacerbations" representing the strongest clinical factor associated with future exacerbation. Thus, to identify additional novel biomarkers associated with asthma exacerbations, "past exacerbation status" must be included as a confounding factor.

OBJECTIVE

This study aimed to characterize the clinical and biomarker features associated with asthma exacerbations in severe asthma.

METHODS

We evaluated clinical parameters from 105 severe asthmatics yearly for 3 years, as well as their exacerbation status. We classified the subjects into 3 groups: (i) consistent non-exacerbators (CNE, subjects who did not experience any exacerbation over the 3-year period); (ii) consistent frequent exacerbators (CFE, subjects with frequent exacerbation, defined as those who had 2 or more exacerbations within 1 year, throughout the 3-year period); and (iii) intermittent exacerbators (IE). We conducted multivariate analysis for comparisons among the groups for multiple factors, including several Th2-related biomarkers, in addition to the "past exacerbation status."

RESULTS

Thirty-nine subjects were classified as CNE, 15 as CFE, and 51 as IE. Frequent exacerbations in the previous year predicted exacerbations for the following year (P < .001). Among the several Th2-related biomarkers, only FeNO was associated with exacerbation status. When we analysed the data after the second visit, the impact of FeNO on predicting future exacerbation remained significant, even after considering the exacerbation status during the first year (P < .05).

CONCLUSIONS AND CLINICAL RELEVANCE

Measurement of FeNO has a significant potential to predict future asthma exacerbation, which is independent of the "past exacerbation history."

Transfer coefficients better reflect emphysematous changes than carbon monoxide diffusing capacity in obstructive lung diseases

The overlap between asthma and chronic obstructive pulmonary disease (COPD) has attracted the interest of pulmonary physicians; thus, measurement of carbon monoxide diffusion capacity (DLco) and/or transfer coefficients (Kco, DLco/V_A) may become valuable in clinical settings. How these parameters behave in chronic obstructive lung diseases is poorly understood. We predicted that Kco might more accurately reflect emphysematous changes in the lungs than DLco. We examined DLco and Kco in nonsmokers and smokers with asthma and investigated their relationships with forced expiratory volume in 1 s (%FEV₁) by group. We then selected nonsmokers (As-NS) and smokers with asthma (As-Sm) in both groups and those with COPD while controlling for the degree of airflow limitation across groups. Emphysema volumes [%lung attenuation volume (%LAV)] and percentage of cross-sectional area of small pulmonary vessels <5 mm² (%CSA_<5) were measured by computed tomography. In As-NS, %Kco was significantly higher when FEV₁% was reduced, but such a correlation was not seen in As-Sm. %Kco successfully differentiated among the three groups when airflow limitation levels were matched. However, %DLc, was significantly reduced only in patients with COPD. Both %LAV and %CSA_<5 were better correlated with %Kco than with %DLco. There was discordance between %DL_CO and %Kco in As-Sm, which was not seen in As-NS. Overall, %Kco better reflects emphysematous changes in obstructive lung diseases than %DLco. NEW & NOTEWORTHY Despite differing behaviors of %Kco and %DLco in several diseases, the characteristics of these parameters have not been fully examined in smokers with asthma. Here, we demonstrated that %Kco is a more sensitive parameter of pathophysiology, better reflecting emphysematous changes in chronic obstructive lung diseases overall, compared with %DLco. Thus, more precise interpretations of %DLco and %Kco may provide clues for understanding the pathophysiology of obstructive lung diseases.

Relationship of annual change in bone mineral density with extent of emphysematous lesions and pulmonary function in patients with COPD

Background

Osteoporosis is a well-known comorbidity in COPD. It is associated with poor health status and prognosis. Although the exact pathomechanisms are unclear, osteoporosis is suggested to be either a comorbidity due to shared risk factors with COPD or a systematic effect of COPD with a cause-effect relationship. This study aimed to evaluate whether progression of osteoporosis is synchronized with that of COPD.

Materials and methods

Data from 103 patients with COPD included in the Hokkaido COPD cohort study were analyzed. Computed tomography (CT) attenuation values of thoracic vertebrae 4, 7, and 10 were measured using custom software, and the average value (average bone density; ABD_4,7,10) was calculated. The percentage of low attenuation volume (LAV%) for each patient was also calculated for evaluation of emphysematous lesions. Annual change in thoracic vertebral CT attenuation, which is strongly correlated with dual-energy X-ray absorptiometry-measured bone mineral density, was compared with that in FEV_1.0 or emphysematous lesions.

Results

In the first CT data set, ABD_4,7,10 was significantly correlated with age (ρ=-0.331; p=0.0006), body mass index (BMI; ρ=0.246; p=0.0136), St George's Respiratory Questionnaire (SGRQ) activity score (ρ=-0.248; p=0.0115), eosinophil count (ρ=0.229; p=0.0198), and LAV% (ρ=-0.372; p=0.0001). However, ABD_4,7,10 was not associated with FEV_1.0. After adjustment for age, BMI, SGRQ activity score, and eosinophil count, no significant relationship was found between ABD_4,7,10 and LAV%. Annual change in ABD_4,7,10 was not associated with annual change in LAV% or FEV_1.0.

Conclusion

Progression of osteoporosis and that of COPD are not directly related or synchronized with each other.

Asthma-like Features and Clinical Course of Chronic Obstructive Pulmonary Disease. An Analysis from the Hokkaido COPD Cohort Study

RATIONALE

Some patients with chronic obstructive pulmonary disease (COPD) have asthma-like features, such as significant bronchodilator reversibility, blood eosinophilia, and/or atopy, even if they are not clinically diagnosed as having asthma. However, the clinical significance of asthma-like features overlapping with COPD remains unclear.

OBJECTIVES

The aim of this study was to assess the effect of asthma-like features on the clinical course of patients with COPD who were adequately treated and followed-up over 10 years.

METHODS

A total of 268 patients with COPD who had been clinically considered as not having asthma by respiratory specialists were included in this study. The asthma-like features included in this study were bronchodilator reversibility (ΔFEV₁, ≥12% and ≥200 ml), blood eosinophilia (≥300 cells/μl), and atopy (positive specific IgE for any inhaled antigen). The annual changes in post-bronchodilator FEV₁ and COPD exacerbations were monitored during the first 5 years, and mortality was followed during the entire 10 years of the study.

MEASUREMENTS AND MAIN RESULTS

Fifty-seven subjects (21%) had bronchodilator reversibility, 52 (19%) had blood eosinophilia, and 67 (25%) had atopy. Subjects with blood eosinophilia had significantly slower annual post-bronchodilator FEV₁ decline; bronchodilator reversibility and atopy did not affect the annual post-bronchodilator FEV₁ decline, and none of the asthma-like features was associated with development of COPD exacerbation. Even if subjects had two or more asthma-like features, they displayed annual post-bronchodilator FEV₁ declines and exacerbation rates similar to those of subjects with one or zero asthma-like features, as well as a lower 10-year mortality rate (P = 0.02).

CONCLUSIONS

The presence of asthma-like features was associated with better clinical course in patients with COPD receiving appropriate treatment.

GENETIC INTERACTIONS BETWEEN ADRB2 AND PTGER4 ON RESPONSES TO SALMETEROL OR MONTELUKAST IN JAPANESE PATIENTS WITH MILD PERSISTENT ASTHMA

BACKGROUND

Long-acting β₂-agonists (LABA) and leukotriene receptor antagonists (LTRA) are two principal agents that can be added to inhaled corticosteroids (ICS) for patients with asthma that is not adequately controlled by ICS alone. In our previous study, the Gly16Arg genotype of the β₂-adrenergic receptor (ADRB2) gene did not influence the differential bronchodilator effect of salmeterol versus montelukast as an add-on therapy to ICS within 16 weeks of follow-up (the J-Blossom study).

METHODS

We examined if genes encoding CYSLTR1, CYSLTR2, PTGER2 or PTGER4 could explain differential responses to salmeterol versus montelukast using the participants of the J-Blossom study. This study included 76 patients with mild-to-moderate asthma. The difference in peak expiratory flow (PEF) (ΔPEF, l/min) after 16 weeks of treatment with salmeterol (ΔPEFsal) versus montelukast (ΔPEFmon) was associated with the genotypes at each of 4 genes. In addition, multivariate analyses were used to identify a gene-gene interaction between ADRB2 gene and each of these 4 genes.

RESULTS

Although none of 4 genes were associated with ΔPEFsal-ΔPEFmon in the univariate analyses, multivariate analysis showed that PTGER4 gene, interacting with ADRB2 Gly16Arg, was associated with ΔPEFsal-ΔPEFmon (p=0.0032).

CONCLUSION

Our findings suggested that the interactions between two genetic loci at ADRB2 and PTGER4 is important in determining the differential response to salmeterol versus montelukast in patients with chronic adult asthma.

Computed tomography (CT)-assessed bronchodilation induced by inhaled indacaterol and glycopyrronium/indacaterol in COPD

BACKGROUND

Our previous studies suggested that the site of bronchodilation on CT might differ between inhaled β2 agonists and inhaled anticholinergics in COPD.

AIM

To assess and compare the bronchodilation effects of inhaled indacaterol and glycopyrronium/indacaterol by airway generation in large airways using CT.

METHODS

CT scans at full inspiration and pulmonary function tests were done in 25 patients with moderate-severe COPD before and 4-5 weeks after daily inhalation of indacaterol and again another 4-5 weeks after inhalation of glycopyrronium/indacaterol. Airway inner luminal area (Ai) at the 3rd (segmental) to 6th generation of 8 selected bronchi, a total of 32 sites, in the right lung was analyzed on 3 occasions. Our proprietary software enables us to select the same airways and the same measurement sites for comparison, with simultaneous confirmation using two screens on the computer.

RESULTS

The overall increase of Ai (ΔAi, %) averaged at all 32 measurement sites induced by glycopyrronium/indacaterol had a significant correlation with FEV1 improvement (r = 0.7466, p < 0.0001). Both ΔAi, % with indacaterol and ΔAi, % with additional glycopyrronium were significant at the 3rd to 6th generations. Remarkable increases in ΔAi, % were found at the 5th and 6th generations in several subjects with indacaterol or additional glycopyrronium. There were no significant site-differences in the bronchodilation pattern caused by indacaterol and by glycopyrronium/indacaterol at any of the 3rd to 6th generations.

CONCLUSIONS

Additional bronchodilation with glycopyrronium was demonstrated by CT at the 3rd to 6th generations, with no site-specific differences in bronchodilation between indacaterol and glycopyrronium/indacaterol. This study was registered in the UMIN Clinical Trials Registry (UMIN-CTR) system (http://www.umin.ac.jp/. ID. UMIN000012043).

Limited reduction of ferrihydrite encrusted by goethite in freshwater sediment

Many physical and chemical processes control the extent of Fe(III) oxyhydroxide reduction by dissimilatory Fe(III)-reducing bacteria. The surface precipitation of secondary Fe minerals on Fe(III) oxyhydroxides limits the extent of microbial Fe(III) reduction, but this phenomenon has not yet been observed in nature. This paper reports the observation of secondary Fe-mineral (goethite) encrustation on ferrihydrite surface within freshwater sediment up to 10 cm deep. The sediment surface was characterized by the predominance of ferrihydrites with biogenic stalks and sheaths. An Fe(II)-oxidizing bacterium (Gallionellaceae) was detected by 16S rRNA gene analysis at sediment depths of 1 and 2 cm. Fe(2+) concentration in the sediment pore water was relatively higher at 2-4 cm depths. The 16S rRNA genes affiliated with dissimilatory Fe(III)-reducing bacteria were detected at 1, 2, and 4 cm depths. The results of the Fe K-edge extended X-ray absorption fine structure (EXAFS) analysis suggested the presence of goethite and siderite at depths below 3 cm. However, the change in the Fe-mineral composition was restricted to sediment depths between 3 and 4 cm, despite the presence of abundant ferrihydrite at depths below 4 cm. An increase in CH4 concentration was observed at deeper than 6 cm. Stable isotopic analysis of CH4 in the pore water indicated that acetoclastic CH4 occurred at depths below 7 cm. Transmission electron microscope observations suggested the presence of goethite and siderite on stalks and sheaths at depths below 3 cm. Results from conversion electron yield EXAFS analysis suggested that goethite dominated at 10 cm depth, thereby indicating that ferrihydrite was encrusted by goethite at this depth. Moreover, the incomplete reduction of ferrihydrite below depths of 4 cm was not due to the lack of organic carbon, but was possibly due to the surface encrustation of goethite on ferrihydrite.

[Lessons from the Hokkaido COPD cohort study]

Hokkaido COPD cohort study is a carefully-designed, well-conducted, prospective observational 10 year-long study, which ended early in 2015. We have obtained a number of clinically-relevant novel findings, some of which are as follows. Severity of emphysema was highly varied even in those individuals whose airflow limitation is comparable. The annual change in forced expiratory volume in 1 second (FEV1) over 5 years was also widely varied with normal distribution among the subjects under appropriate treatment. Some patients maintained their pulmonary function for a long time, and others showed a rapid decline. Emphysema severity, but not pulmonary function, was independently associated with such an inter-subject variation in the annual decline in FEV1. When we explored any biomarkers for predicting the FEV1 decline, a lower leptin/adiponectin ratio alone emerged as an explanatory parameter for the rapid decline, and this was also confirmed in an independent Danish cohort study of different ethnicity. Monitoring of quality of life (QOL), using SGRQ scores, also provided interesting observations. The annual change in total score reflected that of FEV1 decline during the follow-up period. However, activity component in QOL deteriorated in almost all the subjects, while symptom component rather improved in many of the patients under appropriate treatment.

[FACTORS ASSOCIATED WITH THE PRESENCE OF ALLERGEN-SPECIFIC IgE RESPONSES IN ASTHMA PATIENTS WHO HAD NO IgE RESPONSES DETECTABLE BY MAST-26]

AIM

To elucidate the characteristics of patients with asthma who have specific IgE responses to inhaled allergens detected by ImmunoCAP, which is not detectable by MAST-26.

METHODS

A total of 168 patients with adult asthma who reside in the Kanto region were recruited. Levels of total serum IgE and allergen specific IgE antibodies towards 14 common inhaled allergens (MAST-26) were measured. Among these samples, 48 patients with no detectable allergen-specific IgE (group A) and 44 patients with strong sensitization to Dermatophagoides farinae (group B) were selected for further assessment of their sensitization to inhaled allergens such as cockroach and moth using ImmunoCAP.

RESULTS

In group A, ImmunoCAP detected specific IgE responses to some inhaled allergens in 27.1% of the patients. The strongest predictive factor for the presence of allergen-specific IgE responses detected by ImmunoCAP was elevated levels of total serum IgE (p=0.0007). In group B, the presence of IgE responses specific to cockroach or moth by ImmunoCAP were found in 27.8% or 52.3% of the patients, respectively. The predictive factor for the presence of these positive IgE responses was also elevated levels of total serum IgE (p=0.0003).

CONCLUSION

Asthma patients with no detectable specific IgE responses to any inhaled allergens by MAST-26 may be still sensitized to common inhaled allergens, including cockroach and moth. Thus, the presence of allergen-specific IgE responses may be re-assessed by ImmunoCAP in patients with asthma, especially when patients have higher levels of total serum IgE.

Differential changes in quality of life components over 5 years in chronic obstructive pulmonary disease patients

BACKGROUND

The aim of the study was to examine the longitudinal change in quality of life components of patients with chronic obstructive pulmonary disease (COPD).

METHODS

In the Hokkaido COPD Cohort Study, 261 subjects were appropriately treated and followed over 5 years with a 74% follow-up rate at the end. The longitudinal changes in St George's Respiratory Questionnaire (SGRQ) scores were annually evaluated with forced expiratory volume in 1 second (FEV1). The subjects were classified into the rapid decliners, slow decliners, and sustainers based on ΔFEV1/year.

RESULTS

The activity component of SGRQ generally deteriorated over time, and its annual decline was the greatest in the rapid decliners (<25th percentile). In contrast, the symptom component improved significantly year by year in the sustainers (>75 percentile), and it did not deteriorate even in the rapid decliners. Of the baseline data, predictors for worsening of the activity component were older age and lower body mass index. Larger reversibility was related to symptom component improvement. Of the follow-up data, ΔFEV1/year was the best predictor for worsening of the components of SGRQ. Continuous smoking was another factor for worsening of the activity component. For the symptom component, a history of exacerbation by admission definition was the determinant of its deterioration, whereas use of beta agonists was related to improvement.

CONCLUSION

The longitudinal changes of quality of life and their determinants are markedly different and independent between its components. The activity component of SGRQ generally deteriorated over years, while the symptom component rather improved in some patients with COPD under appropriate treatment.

Association of the CAT-262C>T polymorphism with asthma in smokers and the nonemphysematous phenotype of chronic obstructive pulmonary disease

BACKGROUND

Catalase (CAT) is a part of the active antioxidant defense system and has been studied with regard to its association with asthma and chronic obstructive pulmonary disease (COPD), which are heterogeneous obstructive pulmonary diseases characterized by chronic airway inflammation. We hypothesized that the CAT gene might be involved in the common pathogenesis underlying asthma and COPD.

OBJECTIVE

To evaluate the association of CAT polymorphisms with specific phenotypes of asthma and COPD to identify the common underlying pathophysiologic mechanisms of these 2 diseases.

METHODS

The -262C>T and -21A>T polymorphisms in the CAT gene were genotyped in 493 individuals with asthma, 265 with COPD, and 1,076 healthy controls. Asthmatic patients were categorized according to smoking status (smokers and nonsmokers) and age at onset (early onset and adult onset) as part of a case-control study. In patients with COPD, visual scoring (computed tomographic score) was assessed to determine emphysema severity, which was used to evaluate associations with CAT gene polymorphisms.

RESULTS

Overall, the -262C>T and -21A>T polymorphisms were not associated with asthma. However, the -262CT+TT genotype was significantly associated with adult-onset asthma in smokers (P = .005), and a significant interaction between smoking status and the effect of -262C>T genotype on asthma were observed (P = .01). In patients with COPD, this genotype was significantly associated with a low computed tomographic score (P = .03), which indicates a nonemphysematous type of COPD.

CONCLUSION

The present study indicates that the CAT gene is involved in the common pathogenesis underlying adult-onset asthma in smokers and the nonemphysematous type of COPD.

Characterization of biogenic iron oxides collected by the newly designed liquid culture method using diffusion chambers

We designed a new culture method for neutrophilic iron-oxidizing bacteria using liquid medium (i) to study the formation and mineralogical characteristics of biogenic iron oxides (BIOS) and (ii) to apply BIOS to various scientific and engineering applications. An iron-oxidizing bacterium, Mariprofundus ferrooxydans PV-1(T) (ATCC, BAA-1020), was cultured using a set of diffusion chambers to prepare a broad anoxic-oxic interface, upon which BIOS formation is typically observed in natural environments. Iron oxide precipitates were generated in parallel with bacterial growth. A scanning electron microscopy analysis indicated that the morphological features of the iron oxide precipitates in the medium (in vitro BIOS) were similar to those of BIOS collected from natural deep-sea hydrothermal environments in the Northwest Eifuku Seamount field in the northern Mariana Arc (in situ BIOS). Further chemical speciation of both the in vitro and in situ BIOS was examined with X-ray absorption fine structure (XAFS). A bulk XAFS analysis showed that the minerals in both BIOS were mainly ferrihydrite and oligomeric stages of amorphous iron oxyhydroxides with edge-sharing octahedral linkages. The amount of in vitro BIOS produced with the diffusion-chamber method was greater than those produced previously with other culture methods, such as gel-stabilized gradient and batch liquid culture methods. The larger yields of BIOS produced with the new culture method will allow us to clarify in the future the mineralization mechanisms during bacterial growth and to examine the physicochemical properties of BIOS, such as their adsorption to and coprecipitation with various elements and substances.

Clinical features and determinants of COPD exacerbation in the Hokkaido COPD cohort study

Exacerbations are among the major factors that may affect the natural history of chronic obstructive pulmonary disease (COPD). The aim was to investigate the clinical characteristics and determinants of COPD exacerbations in our 5-year observational cohort study which had a very low exacerbation frequency. A total of 279 patients with COPD participated in the Hokkaido COPD cohort study, and 268 subjects who had clinical data for multiple visits were analysed. Exacerbation was defined in multiple ways: the patient's subjective complaint, symptom definition, requiring prescription change, requiring antibiotic treatment, or requiring hospital admission. Exacerbation frequency (events per person per year) was 0.78 ± 1.16, 0.24 ± 0.47, 0.20 ± 0.43, 0.13 ± 0.28 and 0.06 ± 0.19 for subjective complaint and symptom, prescription, antibiotic and hospital admission definitions, respectively. Exacerbation events did not significantly affect the annual decline in forced expiratory volume in 1 s. A high St George's Respiratory Questionnaire total score, especially activity score, and a low body mass index were strongly associated with exacerbation-free survival, exacerbation frequency and development of recurrent exacerbations. Despite the low exacerbation frequency in our cohort, impaired health-related quality of life and weight loss were found to be independent risk factors for COPD exacerbations.

Characteristics of stable chronic obstructive pulmonary disease patients in the pulmonology clinics of seven Asian cities

BACKGROUND AND OBJECTIVES

Chronic obstructive pulmonary disease (COPD) is responsible for significant morbidity and mortality worldwide. We evaluated the characteristics of stable COPD patients in the pulmonology clinics of seven Asian cities and also evaluated whether the exposure to biomass fuels and dusty jobs were related to respiratory symptoms, airflow limitation, and quality of life in the COPD patients.

METHODS

This cross-sectional observational study recruited 922 COPD patients from seven cities of Asia. The patients underwent spirometry and were administered questionnaires about their exposure to cigarette smoking, biomass fuels, and dusty jobs in addition to respiratory symptoms and health related quality of life.

RESULTS

Of the patients, there appeared to be variations from city to city in the history of exposure to biomass fuels and dusty jobs and also in respiratory symptoms of cough, phlegm, wheeze, and dyspnea. These symptoms were more frequent in those COPD patients with a history of exposure to biomass fuels than without and those with a history of exposure to dusty jobs than without (P < 0.01 for all comparisons). Airflow limitation was more severe in those COPD patients with a history of exposure to biomass fuels than without (52.2% predicted versus 55.9% of post-bronchodilator forced expiratory volume in 1 second [FEV(1)], P = 0.009); quality of life was poorer in those with exposure to biomass fuels than without (40.4 versus 36.2 of the St George's Respiratory Questionnaire [SGRQ] total score, P = 0.001). Airflow limitation was more severe in those COPD patients with a history of exposure to dusty jobs than without (51.2% predicted versus 57.3% of post-bronchodilator FEV(1), P < 0.001); quality of life was poorer in those with dusty jobs than without (41.0 versus 34.6 of SGRQ score, P = 0.006).

CONCLUSION

In Asian cities, the characteristics of COPD patients vary and the history of exposure to biomass fuels or dusty jobs was related to frequency of symptoms, severe airflow limitation, and poor quality of life.

Annual change in pulmonary function and clinical phenotype in chronic obstructive pulmonary disease

RATIONALE

Although the rate of annual decline in FEV1 is one of the most important outcome measures in chronic obstructive pulmonary disease (COPD), little is known about intersubject variability based on clinical phenotypes.

OBJECTIVES

To examine the intersubject variability in a 5-year observational cohort study, particularly focusing on emphysema severity.

METHODS

A total of 279 eligible patients with COPD (stages I-IV: 26, 45, 24, and 5%) participated. We conducted a detailed assessment of pulmonary function and computed tomography (CT) at baseline, and performed spirometry every 6 months before and after inhalation of bronchodilator. Smoking status, exacerbation, and pharmacotherapy were carefully monitored. Emphysema severity was evaluated by CT and annual measurements of carbon monoxide transfer coefficient.

MEASUREMENTS AND MAIN RESULTS

Using mixed effects model analysis, the annual decline in post-bronchodilator FEV1 was -32±24 (SD) ml/yr (n=261). We classified the subjects of less than the 25th percentile as Rapid decliners, the 25th to 75th percentile as Slow decliners, and greater than the 75th percentile as Sustainers (-63±2, -31±1, and -2±1 [SE] ml/yr). Emphysema severity, but not %FEV1, showed significant differences among the three groups. Multiple logistic regression analysis demonstrated that the Rapid decliners were independently associated with emphysema severity assessed either by CT or carbon monoxide transfer coefficient. The Sustainers displayed less emphysema and higher levels of circulating eosinophils.

CONCLUSIONS

Emphysema severity is independently associated with a rapid annual decline in FEV1 in COPD. Sustainers and Rapid decliners warrant specific attention in clinical practice.

Chronological Change in Pulmonary Vascular Response to Hypoxia in Hepatopulmonary Syndrome

Here we present a case of hepatopulmonary syndrome (HPS) where spontaneous resolution of severe hypoxaemia occurred with the development of pulmonary hypertension over several years after the initial diagnosis of HPS. The pulmonary vascular responses to hypoxia examined before and after the spontaneous resolution of HPS confirmed that the pathogenesis of HPS could be functional and reversible in nature. To the best of our knowledge, this is the first report demonstrating a remarkable change in the pulmonary vascular response to hypoxia before and after the spontaneous resolution of hypoxaemia in HPS.

Comparison of airway remodelling assessed by computed tomography in asthma and COPD

BACKGROUND

Few studies have directly compared airway remodelling assessed by computed tomography (CT) between asthma and chronic obstructive pulmonary disease (COPD). The present study was conducted to determine whether there are any differences between the two diseases with similar levels of airflow limitation under clinically stable conditions.

METHODS

Subjects included older male asthmatic patients (n = 19) showing FEV(1)/FVC <70% with smoking history less than 5-pack/year. Age- and sex-matched COPD patients (n = 28) who demonstrated similar airflow limitation as asthmatic patients and age-matched healthy non-smokers (n = 13) were recruited. Using proprietary software, eight airways were selected in the right lung, and wall area percent (WA%) and airway luminal area (Ai) were measured at the mid-portion of the 3rd to 6th generation of each airway. For comparison, the average of eight measurements per generation was recorded.

RESULTS

FEV(1)% predicted and FEV(1)/FVC was similar between asthma and COPD (82.3 ± 3.3% vs. 77.6 ± 1.8% and 57.7 ± 1.6% vs. 57.9 ± 1.4%). At any generation, WA% was larger and Ai was smaller in asthma, both followed by COPD and then controls. Significant differences were observed between asthma and controls in WA% of the 3rd to 5th generation and Ai of any generation, while no differences were seen between COPD and controls. There were significant differences in Ai of any generation between asthma and COPD.

CONCLUSIONS

Airway remodelling assessed by CT is more prominent in asthma compared with age- and sex-matched COPD subjects in the 3rd- to 6th generation airways when airflow limitations were similar under stable clinical conditions.

Bronchodilator efficacy of single doses of indacaterol in Japanese patients with COPD: A randomised, double-blind, placebo-controlled trial

BACKGROUND

Indacaterol is an investigational, novel, inhaled once-daily ultra-long-acting beta-2 agonist for the treatment of chronic obstructive pulmonary disease (COPD). This study evaluated the 24-h bronchodilatory efficacy and safety of indacaterol in Japanese patients with COPD.

METHODS

This Phase-II, randomised, placebo-controlled, crossover study comprised four double-blind, single-dose treatment periods (washout between periods: 14-28 days). Japanese patients aged 40-75 years with moderate-to-severe COPD were randomised to receive single doses of indacaterol (150, 300, or 600 microg) or placebo via a single-dose dry-powder inhaler. Efficacy (primary endpoint: standardised FEV(1)AUC(22-24h)) and safety were assessed for 24 h post-dose in each treatment period.

RESULTS

Of the 50 patients randomised (92% male; mean age, 67.2 years), 45 completed the study. Standardised FEV(1)AUC(22-24h) was significantly higher for all indacaterol doses as compared with placebo, with clinically relevant differences of 130, 160, and 170 mL for 150, 300, and 600 microg, respectively (P < 0.001). The improvement in FEV(1) was seen as early as 5 min post-dose with indacaterol and sustained for 24 h (P < 0.001 vs placebo at all time points). All indacaterol doses were well tolerated and showed no clinically meaningful effect on pulse rate, blood pressure, QTc interval, and laboratory parameters when compared with placebo.

CONCLUSIONS

In the Japanese COPD population studied, single doses of indacaterol (150, 300, and 600 microg) provided sustained 24-h bronchodilation, with onset of action within 5 min post-dose. All doses were well tolerated. These results are consistent with data from Caucasian populations.

Airflow limitation and airway dimensions assessed per bronchial generation in older asthmatics

BACKGROUND

Computed tomography (CT) has been used for non-invasive quantitative assessment of airway dimensions, potentially showing airway remodeling, in asthma. However, most studies have examined either only one airway or only airways in anatomically unidentified cross-sections. Using software capable of precisely identifying the generation of airways and measuring airway dimensions perpendicular to the long axis of airways, we examined, in older patients with stable asthma, how inter-subject variation in airway dimensions correlated among the 3rd to 6th generation of airways, and then examined relationships between airway dimensions of each generation and indices of airflow limitation.

METHODS

Subjects aged ≥55 years old comprised 59 asthmatic patients who underwent CT and pulmonary function tests on the same day. We measured airway wall area (WA%) and inner luminal area (Ai) from the 3rd to the 6th generation of eight bronchi in the right lung.

RESULTS

Excellent correlations were identified for both WA% and Ai among the generations (r = 0.744-0.930 for WA%) when we took the average of all measured bronchi per generation as a personal representative value. Significant correlations of airflow limitation indices with both WA% and Ai/BSA were found at each of the 3rd to 6th generations with similar correlation coefficients (WA% for FEV(1) %predicted, r = -0.410 to -0.556).

CONCLUSIONS

In older patients with stable asthma, airway wall thickening and narrowing might occur in a parallel manner through 3rd to 6th generation airways. Airway dimensions at these areas of airways may thus have significant and similar correlations with indices of airflow limitation.

Relationship between improved airflow limitation and changes in airway calibre induced by inhaled anticholinergic agents in COPD

BACKGROUND

Although airflow limitation improved by inhaled anticholinergic drugs varies among individuals with chronic obstructive pulmonary disease (COPD), the relationship between actual bronchodilation and improved pulmonary function and where in the lung such bronchodilation occurs remains unknown. A study was undertaken to determine the relationship between improved pulmonary function and changes in airway calibre at various sites in the airways in response to inhaled anticholinergic agents in patients with COPD using three-dimensional computed tomography (CT).

METHODS

CT scans were performed at deep inspiration and detailed pulmonary function tests before and 1 week after daily inhalations of tiotropium bromide in 15 patients with clinically stable COPD. The airway luminal area was examined at the third (segmental) to the sixth generations of eight bronchi in the right lung.

RESULTS

Bronchodilation was demonstrated by an overall average increase of 39% in the inner luminal area, and the mean (SE) forced expiratory volume in 1 s (FEV(1)) increased from 1.23 (0.11) l to 1.47 (0.13) l. The magnitude of bronchodilation was closely correlated with improved pulmonary function, particularly with that of FEV(1) (r = 0.843, p<0.001). Such correlations were significant at the fourth to the sixth generation but not at the third generation of bronchi, and the slope of the regression lines became steeper from the third to the sixth generation.

CONCLUSIONS

Inhaled anticholinergic agents induce overall bronchodilation which is in proportion to improvements in FEV(1) in patients with COPD. Bronchodilation at the distal rather than the proximal airways is the determinant of functional improvement.

Effects of green tea polyphenol on methylation status of RECK gene and cancer cell invasion in oral squamous cell carcinoma cells

RECK is a novel tumour suppressor gene that negatively regulates matrix metalloproteinases (MMPs) and inhibits tumour invasion, angiogenesis and metastasis. In the present study, we investigated the effects of epigallocatechin-3-gallate (EGCG), a major polyphenol in green tea, on the methylation status of the RECK gene and cancer invasion in oral squamous cell carcinoma cell lines. Our results showed that treatment of oral cancer cells with EGCG partially reversed the hypermethylation status of the RECK gene and significantly enhanced the expression level of RECK mRNA. Inhibition of MMP-2 and MMP-9 levels was also observed in these cells after treatment with EGCG. Interestingly, EGCG significantly suppressed cancer cell-invasive ability by decreasing the number of invasive foci (P<0.0001) as well as invasion depth (P<0.005) in three-dimensional collagen invasion model. Although further investigation is required to assess the extent of contribution of RECK on MMPs to the suppression of invasive behaviour, these results support the conclusion that EGCG plays a key role in suppressing cell invasion through multiple mechanisms, possibly by demethylation effect on MMP inhibitors such as RECK.

[Evaluation of atopy by antigen specific IGE antibody]

BACKGROUND

Atopy is usually defined as the genetic propensity to produce IgE antibodies (Abs) specific to common environmental allergens. The aim of this study was to evaluate impacts of the number of allergens examined on prevalence of atopy.

METHODS

Subjects comprised 116 healthy controls, 104 patients with asthma, 294 patients with COPD, 64 patients with sarcoidosis and 218 residents of Kamishihoro town. Total serum immunoglobulin E and antigen-specific IgE antibody levels for 26 common allergens were examined. Atopy was defined as positive IgE Abs specific to > or =1 allergen. We serially increased the number of allergens to define atopy from the most common allergens in order of frequency, and changes in prevalence of atopy were evaluated. In residents of Kamishihoro, betula pollen antigen was also examined, as this antigen is very common in the town.

RESULTS

The increasing prevalence of atopy was dramatically reduced relative to the number of allergens examined. Among residents of Kamishihoro town, 5 cases displayed specific IgE Abs to this allergen alone and prevalence of atopy was increased 2.3 percents.

CONCLUSION

When atopy was defined as the production of specific IgE Abs to common allergens, roughly 10 of the most common allergens may cover common environmental allergens.

Functional single nucleotide polymorphisms of the CCL5 gene and nonemphysematous phenotype in COPD patients

It was previously reported that the gain-of-function -28 guanine allele of the promoter single nucleotide polymorphism (SNP; cytosine to guanine substitution of nucleotide -28 (-28C>G)) in the CC chemokine ligand 5 gene (CCL5) was associated with susceptibility to late-onset asthma in patients who developed asthma at age > or =40 yrs. The clinical diagnosis of chronic obstructive pulmonary disease (COPD) includes emphysema and small airway disease, and upregulation of CCL5 has been described in the airways of patients with COPD. It was hypothesised that CCL5 has a genetic impact upon the variable expression of emphysema in patients with COPD. Patients with COPD were studied (n = 267). All of the patients underwent pulmonary high-resolution computed tomography (CT), and visual scoring (CT score) was performed to determine emphysema severity. Three SNPs of CCL5 were genotyped, including -403G>A, -28C>G and 375T>C. A significant difference was found in CT score according to CCL5 genotype; the -28G allele was inversely associated with CT score. When the analysis was confined to 180 patients with bronchial reversibility of <15%, even stronger evidence for this association was noted. Functional single nucleotide polymorphisms in the CC chemokine ligand 5 gene were associated with milder emphysema. Together with previous findings, the present study may identify the CC chemokine ligand 5 gene as part of a common pathway in the pathogenesis of late-onset asthma and chronic obstructive pulmonary disease with milder emphysema.