Rationale: Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation caused by emphysema and/or airway narrowing. Computed tomography has been widely used to assess emphysema severity, but less attention has been paid to the assessment of airway disease using computed tomography. Conclusions:We are the first to use three-dimensional computed tomography to demonstrate that airflow limitation in COPD is more closely related to the dimensions of the distal (small) airways than proximal (large) airways.
Emphysema severity is independently associated with a rapid annual decline in FEV1 in COPD. Sustainers and Rapid decliners warrant specific attention in clinical practice.
Pulmonary macrophages are one of the sources of various antioxidant and detoxification enzymes for which NF-E2-related factor 2 (Nrf2) is a key transcriptional factor. Although Nrf2 deficiency reportedly induces severe emphysema in mice exposed to cigarette smoke (CS), no reports have studied Nrf2 regulation in chronic obstructive pulmonary disease (COPD). In this study, Nrf2 activation in response to CS was evaluated in human alveolar macrophages, and age-related differences in CS-induced Nrf2 regulation in mouse alveolar macrophages were determined. Furthermore, Nrf2 mRNA levels in human macrophages harvested by bronchoalveolar lavage or laser capture microdissection were measured. CS induced nuclear Nrf2 accumulation and up-regulation of Nrf2 target genes without substantial changes in Nrf2 mRNA levels in human alveolar macrophages. In humans, the Nrf2 mRNA level in lavaged macrophages of young subjects (n = 14) was independent of smoking status; however, the Nrf2 mRNA level was down-regulated in the lavaged macrophages of older current smokers (n = 14) compared with older nonsmokers (n = 9) (P < 0.001). Among older subjects, the macrophage Nrf2 mRNA level was inversely correlated with oxidized glutathione and carbonylated albumin levels in bronchoalveolar lavage fluid. In mice, aging suppressed the CS-induced up-regulation of Nrf2 target genes, as well as Nrf2, in alveolar macrophages. Furthermore, the Nrf2 mRNA level was decreased in laser capture microdissection-retrieved macrophages obtained from subjects with COPD (n = 10) compared with control subjects (n = 10) (P = 0.001). In conclusion, CS induces Nrf2 activation in macrophages, and Nrf2 expression is decreased in the macrophages of older current smokers and patients with COPD.
Background: Airflow limitation in chronic obstructive pulmonary disease (COPD) is caused by a mixture of small airway disease and emphysema, the relative contributions of which may vary among patients. Phenotypes of COPD classified purely based on severity of emphysema are not well defined and may be different from the classic phenotypes of ''pink puffers'' and ''blue bloaters''. Methods: To characterise clinical phenotypes based on severity of emphysema, 274 subjects with COPD were recruited, excluding those with physician-diagnosed bronchial asthma. For all subjects a detailed interview of disease history and symptoms, quality of life (QOL) measurement, blood sampling, pulmonary function tests before and after inhalation of salbutamol (0.4 mg) and high-resolution CT scanning were performed. Results: Severity of emphysema visually evaluated varied widely even among subjects with the same stage of disease. No significant differences were noted among three groups of subjects classified by severity of emphysema in age, smoking history, chronic bronchitis symptoms, blood eosinophil count, serum IgE level or bronchodilator response. However, subjects with severe emphysema had significantly lower body mass index (BMI) and poorer QOL scores, evaluated using St George's Respiratory Questionnaire (SGRQ), than those with no/mild emphysema (mean (SD) BMI 21.2 (0.5) vs 23.5 (0.3) kg/m 2 , respectively; SGRQ total score 40 (3) vs 28 (2), respectively; p,0.001 for both). These characteristics held true even if subjects with the same degree of airflow limitation were chosen. Conclusions: The severity of emphysema varies widely even in patients with the same stage of COPD, and chronic bronchitis symptoms are equally distributed irrespective of emphysema severity. Patients with the phenotype in which emphysema predominates have lower BMI and poorer health-related QOL.
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. @ERSpublications Impaired health-related quality of life and weight loss are independent risk factors for COPD exacerbations
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