High-fiber diets attenuate emphysema development via modulation of gut microbiota and metabolism.

Dietary fiber functions as a prebiotic to determine the gut microbe composition. The gut microbiota influences the metabolic functions and immune responses in human health. The gut microbiota and metabolites produced by various dietary components not only modulate immunity but also impact various organs. Although recent findings have suggested that microbial dysbiosis is associated with several respiratory diseases, including asthma, cystic fibrosis, and allergy, the role of microbiota and metabolites produced by dietary nutrients with respect to pulmonary disease remains unclear. Therefore, we explored whether the gut microbiota and metabolites produced by dietary fiber components could influence a cigarette smoking (CS)-exposed emphysema model. In this study, it was demonstrated that a high-fiber diet including non-fermentable cellulose and fermentable pectin attenuated the pathological changes associated with emphysema progression and the inflammatory response in CS-exposed emphysema mice. Moreover, we observed that different types of dietary fiber could modulate the diversity of gut microbiota and differentially impacted anabolism including the generation of short-chain fatty acids, bile acids, and sphingolipids. Overall, the results of this study indicate that high-fiber diets play a beneficial role in the gut microbiota-metabolite modulation and substantially affect CS-exposed emphysema mice. Furthermore, this study suggests the therapeutic potential of gut microbiota and metabolites from a high-fiber diet in emphysema via local and systemic inflammation inhibition, which may be useful in the development of a new COPD treatment plan.

Effects of treatment with long-acting muscarinic antagonists (LAMA) and long-acting beta-agonists (LABA) on lung function improvement in patients with bronchiectasis: an observational study.

BACKGROUND: Patients with bronchiectasis are often treated with bronchodilators such as long-acting muscarinic antagonists (LAMA) or long-acting beta-agonists (LABA) for their symptoms, but empirical evidence supporting such practice is sparse. We evaluated the effect of LAMA and LABA on lung function improvement in patients with bronchiectasis. METHODS: Using the in-house patient database at a tertiary referral hospital in Seoul, South Korea, we extracted data from patients diagnosed as bronchiectasis with computed tomography (CT) scan and treated with LAMA, LABA, or both. Patients with asthma, chronic obstructive pulmonary disease (COPD) or a history of cigarette smoking were excluded, and a subgroup analysis was performed in patients who did not receive concurrent treatments such as antibiotics, mucolytics or systemic steroids that may affect lung function improvement. RESULTS: A total of 230 patients (males: 32.6%, median age: 60 years) were analyzed. Their mean forced expiratory volume in 1 second (FEV1) was 53.3% of the predicted value [standard deviation (SD), 15.3]. The patients received LAMA (n=95), LABA (n=36), or both (LAMA-LABA; n=99), after which their FEV1 values were increased by 0.102 liters (SD, 0.208; P<0.001), 0.133 liters (SD, 0.181; P<0.001), and 0.122 liters (SD, 0.230; P<0.001), respectively. In a subgroup of 97 patients who did not receive concurrent treatments, the FEV1 was increased by with 0.107 liters (SD, 0.167; P<0.001), 0.165 liters (SD, 0.209; P=0.005), and 0.165 liters (SD, 0.187; P<0.001) in the LAMA, LABA, and LAMA-LABA groups, respectively. Baseline FEV1 had a significant negative correlation with response to bronchodilator treatment in the total patient cohort (R=-0.242, P<0.001) and the subgroup of patients without concurrent treatments (R=-0.386, P<0.001). CONCLUSIONS: Treatment with bronchodilators such as LAMA or LABA was effective in improving lung function in patients with bronchiectasis, regardless of concurrent treatments that also improve lung function. These data may support the use of LAMA and LABA in patients with bronchiectasis.

In Vitro MIC Values of Rifampin and Ethambutol and Treatment Outcome in Mycobacterium avium Complex Lung Disease.

Although it is known that the in vitro MICs of rifampin and ethambutol are poorly correlated with the clinical response in Mycobacterium avium complex (MAC) lung disease (MAC-LD), evidence for this is limited. This study investigated the association between treatment outcome and the in vitro MICs of rifampin and ethambutol in patients with MAC-LD. Among patients diagnosed with macrolide-susceptible MAC-LD between January 2008 and December 2013, 274 patients who were treated with a standard regimen for ≥12 months until August 2017 and whose in vitro MIC results were available were enrolled at a tertiary referral center in South Korea. The MICs of antimicrobial agents were determined using the broth microdilution method. The mean age of the included patients was 60.4 years. The overall treatment success rate was 79.6% (218/274 patients) and tended to decrease with increasing MICs of rifampin and ethambutol, particularly at MICs of ≥8 µg/ml. Treatment success rate was significantly different between MAC isolates with MICs of ≥8 µg/ml for rifampin and ethambutol and those with MICs of <8 µg/ml for rifampin and/or ethambutol (64.9% versus 85.3%, P < 0.001). Multivariate analysis showed that an MIC of ≥8 µg/ml for both drugs and initial sputum acid-fast bacillus (AFB) smear positivity were independent risk factors for an unfavorable response (adjusted odds ratio [OR] = 3.154, 95% confidence interval [CI] = 1.641 to 6.063, and P = 0.001 for an MIC of ≥8 µg/ml; adjusted OR = 2.769, 95% CI = 1.420 to 5.399, and P = 0.003 for initial sputum AFB smear positivity). These findings suggest that the in vitro MICs of rifampin and ethambutol may be related to treatment outcome in MAC-LD.

Improvement in Ventilation-Perfusion Mismatch after Bronchoscopic Lung Volume Reduction: Quantitative Image Analysis.

Purpose To evaluate whether bronchoscopic lung volume reduction (BLVR) increases ventilation and therefore improves ventilation-perfusion (V/Q) mismatch. Materials and Methods All patients provided written informed consent to be included in this study, which was approved by the Institutional Review Board (2013-0368) of Asan Medical Center. The physiologic changes that occurred after BLVR were measured by using xenon-enhanced ventilation and iodine-enhanced perfusion dual-energy computed tomography (CT). Patients with severe emphysema plus hyperinflation who did not respond to usual treatments were eligible. Pulmonary function tests, the 6-minute walking distance (6MWD) test, quality of life assessment, and dual-energy CT were performed at baseline and 3 months after BLVR. The effect of BLVR was assessed with repeated-measures analysis of variance. Results Twenty-one patients were enrolled in this study (median age, 68 years; mean forced expiratory volume in 1 second [FEV1], 0.75 L ± 0.29). After BLVR, FEV1 (P < .001) and 6MWD (P = .002) improved significantly. Despite the reduction in lung volume (-0.39 L ± 0.44), both ventilation per voxel (P < .001) and total ventilation (P = .01) improved after BLVR. However, neither perfusion per voxel (P = .16) nor total perfusion changed significantly (P = .49). Patients with lung volume reduction of 50% or greater had significantly better improvement in FEV1 (P = .02) and ventilation per voxel (P = .03) than patients with lung volume reduction of less than 50%. V/Q mismatch also improved after BLVR (P = .005), mainly owing to the improvement in ventilation. Conclusion The dual-energy CT analyses showed that BLVR improved ventilation and V/Q mismatch. This increased lung efficiency may be the primary mechanism of improvement after BLVR, despite the reduction in lung volume. © RSNA, 2017 Online supplemental material is available for this article.