Shigeo Muro

High sensitivity C-reactive protein in asthma

Asthma is characterised by chronic inflammation of the airways, but the relevance of high-sensitivity assays for C-reactive protein (hs-CRP), which are known to be a sensitive marker of low-grade systemic inflammation, has not been fully studied in asthma. The objective was to examine serum hs-CRP levels in patients with asthma and their relationship to clinical characteristics and degree of airway inflammation. Serum hs-CRP levels were cross-sectionally examined in steroid-naive (n = 22) and steroid-inhaling (n = 23) adult patients with asthma and healthy controls (n = 14). All were nonsmokers. Serum hs-CRP levels were significantly increased in steroid-naive patients (mean±sd 1.33±1.48 mg·L−1) compared with controls (0.21±0.30 mg·L−1), but not in patients on inhaled corticosteroid. Among steroid-naive patients, serum hs-CRP levels significantly negatively correlated with indices of pulmonary function (forced expiratory volume in one second/forced vital capacity and forced mid-expiratory flow) and positively with sputum eosinophil count. Among patients on inhaled corticosteroid, hs-CRP levels did not correlate with any indices. In conclusion, an increase in serum C-reactive protein levels measured by high-sensitivity assays may be associated with airflow obstruction and airway inflammation, and may serve as a surrogate marker of airway inflammation in asthma.

CT Scan Findings of Emphysema Predict Mortality in COPD

BACKGROUND Emphysematous change as assessed by CT imaging has been reported to correlate with COPD prognostic factors such as FEV(1) and diffusing capacity of the lung for carbon monoxide (Dlco). However, few studies have assessed the relationship between CT scan assessment and COPD mortality from mild to severe stages of the disease. In this study, we analyzed this relationship in patients with various stages of COPD. METHODS Two hundred and fifty-one outpatients with stable COPD were included in the study. CT scan and pulmonary function tests were performed at study entry in a single institution. The percentage of low attenuation area was measured to quantitatively evaluate emphysematous change with a custom-made software. Prognostic data also were collected, and the median follow-up time was 8 years. RESULTS Of the 251 patients, 79 died, with 40 classified as respiratory deaths not involving lung cancer. Univariate Cox analysis revealed that emphysematous change as assessed by CT scan, lung function, age, or BMI were significantly correlated with mortality. Multivariate analysis revealed that emphysematous change as assessed by CT scan had the best association with mortality. CONCLUSIONS Emphysematous change as assessed by CT scan predicts respiratory mortality in outpatients with various stages of COPD.

Impact of gastro-oesophageal reflux disease symptoms on COPD exacerbation

Background: The association between gastro-oesophageal reflux disease (GORD) and chronic obstructive pulmonary disease (COPD) exacerbation has so far remained unclear. Objective: To prospectively establish the clinical significance of GORD symptoms on exacerbation. Methods: 82 patients with COPD and 40 age matched controls were enrolled in this study. Symptoms were evaluated by a questionnaire using the Frequency Scale for the Symptoms of GORD (FSSG). Patients with COPD were prospectively surveyed for 6 months, and episodes of exacerbation were identified using a diary based on modified Anthonisen’s criteria. Exhaled breath condensate (EBC) pH was measured in both groups, and induced sputum was evaluated in patients with COPD. Results: Positive GORD symptoms were reported in 22 (26.8%) patients with COPD and in five (12.5%) controls (p = 0.10). The frequency of exacerbations was significantly associated with the FSSG score (p = 0.03, r = 0.24, 95% CI 0.02 to 0.43). Multiple regression analysis revealed that GORD symptoms were significantly associated with the occurrence of exacerbations (p<0.01; relative risk 6.55, 95% CI 1.86 to 23.11). EBC pH was inversely correlated with FSSG score in both groups (p = 0.01, r = –0.37, 95% CI –0.55 to −0.14 in patients with COPD, and p<0.01, r = –0.45, 95% CI –0.67 to −0.16 in control subjects). Conclusions: GORD symptoms were identified as an important factor associated with COPD exacerbation.

Comparison of low attenuation areas on computed tomographic scans between inner and outer segments of the lung in patients with chronic obstructive pulmonary disease: incidence and contribution to lung function

BACKGROUND The low attenuation areas on computed tomographic (CT) scans have been reported to represent emphysematous changes of the lung. However, the regional distribution of emphysema between the inner and outer segments of the lung has not been adequately studied. In this study the regional distribution of low attenuation areas has been compared by quantitative CT analysis and the contribution of the regional distribution to pulmonary function tests evaluated in patients with chronic obstructive pulmonary disease (COPD). METHODS Chest CT images and the results of pulmonary function tests were obtained from 73 patients with COPD. The lung images were divided into inner and outer segments in the upper (cranial), middle, and lower (caudal) sections. The percentage ratio of low attenuation area to corresponding lung area (LAA%) was then calculated. The LAA% of each segment was also compared with the results of pulmonary function tests. RESULTS The mean (SD) LAA% of the inner segment was 39.1 (18.5) compared with 28.1 (13.2) for the outer segment (p<0.0001). Linear and multiple regression analyses revealed that airflow limitation is closely correlated with the inner segment LAA% of the lower lung. In contrast, the carbon monoxide transfer factor is closely correlated with the inner segment LAA% of the upper lung. CONCLUSION Low attenuation areas on CT scans are more often found in the inner segment of the lung than in the outer segment, and the contribution of the inner segment to pulmonary function tests may be greater than the outer segment.

Relationship Between Pulmonary Emphysema and Osteoporosis Assessed by CT in Patients With COPD

BACKGROUND Osteoporosis is one of the important systemic features of COPD. Although COPD itself is regarded as one risk factor for osteoporosis, the relationship between the extent of emphysema and reduced bone density is still unclear. Our first aim was therefore to measure vertebral bone density and the percentage of low-attenuation area (LAA%) in the lungs using chest CT scans in COPD patients. Our second aim was to investigate the relationships among CT scan measurements, anthropometric parameters, and pulmonary function. METHODS Chest CT scans and pulmonary function tests were performed in 65 male patients with COPD. Using CT images, the CT scan density of the thoracic and lumbar vertebrae (T4, T7, T10, and L1) and the LAA% were measured quantitatively, and their correlations were analyzed. RESULTS Linear regression analyses revealed that LAA% had a significant negative correlation with bone mineral density (BMD) [r = -0.522]. In addition, multiple regression analysis showed that only LAA% and body mass index (BMI) were predictive of BMD among age, BMI, smoking index, FEV(1), arterial blood gas, and LAA%. CONCLUSIONS The extent of pulmonary emphysema significantly correlated with reduced bone density. Our study suggested that COPD itself could be a risk factor for osteoporosis and that chest CT scanning is useful for the management of COPD as a systemic disease.

Effects of obstructive sleep apnea syndrome on serum aminotransferase levels in obese patients

PURPOSE Obesity has been associated with obstructive sleep apnea and hepatic steatosis. We investigated the effects of obstructive sleep apnea and treatment with nasal continuous positive airway pressure (CPAP) on serum aminotransferase levels in obese patients. METHODS We studied 40 obese men with obstructive sleep apnea syndrome. None had hepatitis B antigen or C antibody, autoimmune disease, or an excessive intake of alcohol. Serum levels of aspartate aminotransferase, alanine aminotransferase, triglyceride, glucose, insulin, and leptin were determined in the afternoon and in the morning immediately after sleep, before and after nasal CPAP treatment. RESULTS Aminotransferase levels were abnormal in 35% (n = 14) of patients. Before treatment, mean (+/- SD) aspartate aminotransferase levels were higher in the morning than in the previous afternoon (presleep, 34 +/- 20 IU/L; postsleep, 39 +/- 28 IU/L; P = 0.006). The overnight mean increases in aminotransferase levels were less marked after the first night of nasal CPAP treatment (aspartate aminotransferase: from 6 +/- 11 IU/L to 2 +/- 6 IU/L, P = 0.0003; alanine aminotransferase: from 5 +/- 9 IU/L to 2 +/- 6 IU/L, P = 0.006). Leptin levels (n = 23) decreased significantly after treatment (P = 0.0002), whereas insulin resistance (calculated by the homeostasis model assessment method) and triglyceride levels were unchanged. Improvements in aspartate and alanine aminotransferase levels were maintained after 1 and 6 months of nasal CPAP treatment. CONCLUSION Nasal CPAP therapy may have beneficial effects on serum aminotransferase abnormalities in obese patients who have obstructive sleep apnea.

Body mass index in male patients with COPD: correlation with low attenuation areas on CT

Background: Chronic obstructive pulmonary disease (COPD) is characterised by the presence of airflow limitation caused by loss of lung elasticity and/or airway narrowing. The pathological hallmark of loss of lung elasticity is emphysema, and airway wall remodelling contributes to the airway narrowing. Using CT, these lesions can be assessed by measuring low attenuation areas (LAA) and airway wall thickness/luminal area, respectively. As previously reported, COPD can be divided into airway dominant, emphysema dominant and mixed phenotypes using CT. In this study, it is postulated that a patient’s physique may be associated with the relative contribution of these lesions to airflow obstruction. Methods: CT was used to evaluate emphysema and airway dimensions in 201 patients with COPD. Emphysema was evaluated using percentage of LAA voxels (LAA%) and airway lesion was estimated by percentage wall area (WA%). Patients were divided into four phenotypes using LAA% and WA%. Results: Body mass index (BMI) was significantly lower in the higher LAA% phenotype (ie, emphysema dominant and mixed phenotypes). BMI correlated with LAA% (ρ = −0.557, p<0.0001) but not with WA%. BMI was significantly lower in the emphysema dominant phenotype than in the airway dominant phenotype, while there was no difference in forced expiratory volume in 1 s %predicted between the two. Conclusion: A low BMI is associated with the presence of emphysema, but not with airway wall thickening, in male smokers who have COPD. These results support the concept of different COPD phenotypes and suggest that there may be different systemic manifestations of these phenotypes.

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 of airway wall thickening to an imbalance between matrix metalloproteinase-9 and its inhibitor in asthma

Background: The balance between matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) may be critical in extracellular matrix remodelling, a characteristic of asthmatic airways. An excess of TIMP-1 over MMP-9 has been associated with chronic airflow obstruction but the mechanisms underlying this association remain unknown. Recent computed tomographic (CT) studies indicate that airway wall thickening is associated with chronic airflow obstruction. Methods: Sputum levels of MMP-9, TIMP-1, and their molar ratio were examined in 26 patients with stable asthma and their relationship with pulmonary function and airway wall thickness, assessed by a validated CT technique which measured wall area corrected by body surface area (WA/BSA), the ratio of WA to outer wall area (WA%), and the absolute wall thickness corrected by √BSA of a segmental bronchus (T/√BSA), was examined. Results: Sputum MMP-9 levels were inversely correlated with WA% and TIMP-1 levels were positively correlated with WA/BSA and T/√BSA. The MMP-9/TIMP-1 molar ratio was inversely correlated with WA% and T/√BSA and positively correlated with post-bronchodilator values of mid-forced expiratory flow and maximum expiratory flow at the quartile of lung volume. Conclusion: Excess TIMP-1 may have a pathogenetic role in airway wall thickening in asthmatic patients which may result in chronic airflow obstruction.

Thioredoxin-1 Ameliorates Cigarette Smoke-Induced Lung Inflammation and Emphysema in Mice

Cigarette smoking is associated with the development of inflammatory lung diseases representing major health problems world-wide. We hypothesized that the redox-regulating molecule thioredoxin-1 (TRX), which shows anti-inflammatory, antioxidative, and antiapoptotic effects, could be induced by cigarette smoke (CS) and contribute to protect against CS-induced inflammation and lung destruction. In an acute study, human TRX transgenic mice and C57BL6/J mice were exposed to mainstream CS for 3 days. In the lungs of CS-exposed mice, bronchial epithelial injury and bronchoalveolar lavage neutrophilia were observed. Oxidative stress and apoptosis were enhanced, and the expression of cytokines macrophage inflammatory protein-2 and tumor necrosis factor (TNF)-α was increased 15.3- and 2.4-fold, respectively. Compared with C57BL6/J mice, TRX-transgenic mice had significantly less inflammation, oxidative damage, and apoptosis, as well as decreased levels of matrix metalloprotease-12 mRNA and serum TNF-α. When recombinant human TRX (40 μg/body/day, 3 days) was injected i.p. into CS-exposed C57BL6/J mice, a significant effect to offer protection against CS-induced lung injury was observed through suppression of neutrophil influx. In the chronic study, TRX-transgenic mice and C57BL6/J mice were exposed to CS for 6 months. This chronic exposure caused pulmonary emphysema in C57BL6/J mice accompanying prominent infiltration of macrophages and neutrophils to lung. These pathological changes were significantly suppressed in TRX-transgenic mice. In conclusion, TRX induction ameliorated CS-induced lung inflammation and emphysema in mice. TRX-1 may therefore play a preventive or therapeutic role in lung inflammatory disorders such as chronic obstructive pulmonary disease.