The diagnostic impact of fractional exhaled nitric oxide for asthmatic cough in nontuberculous mycobacterial pulmonary disease.

BACKGROUND: Measurement of exhaled nitric oxide (FeNO) is a potentially useful diagnostic test for asthma. However, no study has explored the relationship between FeNO and respiratory symptoms of nontuberculous mycobacterial pulmonary disease (NTM-PD) complicated with asthma. The objective of this study was to assess the utility of measuring FeNO levels in patients with NTM-PD complicated by asthma. METHODS: In this single-center retrospective cohort study, 140 NTM-PD patients with FeNO measured were enrolled. We selected NTM-PD patients who complicated with asthma as the NTM+BA group, defined using the following criteria: NTM patients with symptoms consistent with asthma, and NTM patients with symptomatic improvement after diagnostic therapy with ICS ± a long-acting beta 2-agonist (LABA). We then calculated a diagnostic cutoff point to distinguish between the NTM+BA groups and the NTM groups (all others). High-resolution computed tomography (HRCT) images were evaluated using the CT scoring system and their association with FeNO was examined. RESULTS: A total of 89 patients were included in the study. (31 in the NTM+BA group and 58 in the NTM group). Compared with the NTM group, the NTM+BA group had higher rates of allergic disease (51.6% vs. 22.4%; p=0.0085) and higher FeNO values (median, 23 [interquartile range {IQR}, 15.0-43.0] ppb vs. median, 17 [IQR, 11.8-23.0] ppb; p=0.015). With diagnostic asthma care using mainly ICS/LABA with reference to the FeNO, most patients (91.0%, 20/22) in the NTM-preceding subgroup in the NTM+BA group demonstrated a prompt improvement of their symptoms and AFB culture findings did not worsen (Culture positive rate (%): Pre-treatment: 59.1% vs. Post-treatment: 40.9%, p=0.3660) at 6 months after starting diagnostic therapy. The optimal diagnostic cutoff point of FeNO to distinguish between the two groups was calculated as 21.5 ppb by the ROC curve (sensitivity 75%, specificity 71.93%, p<0.0001; area under the curve: 0.7989). No significant correlation was observed between FeNO and the severity of CT images in the patients. CONCLUSIONS: A certain number of patients with NTM-PD showed exacerbated respiratory symptoms due to asthmatic complications. Elevated FeNO levels suggest asthma complications, even in patients with NTM.

Laryngeal widening and adequate ventilation by expiratory pressure load training improve aerobic capacity in COPD: a randomised controlled trial.

RATIONALE: Despite strategies acting on peripheral airway obstruction in chronic obstructive pulmonary disease (COPD), exercise intolerance remains inadequately improved. We hypothesised that laryngeal narrowing is a potential treatment target of expiratory pressure load training (EPT) to improve exercise intolerance in COPD. METHODS: The effect of 3-month EPT was assessed in 47 patients with COPD divided into Global Initiative for Chronic Obstructive Lung Disease (GOLD) mild-to-moderate (I-II) and severe-to-very severe (III-IV), randomly allocating 1:1 to EPT or control groups. The primary outcome was endurance time in the constant work rate exercise test in GOLD III-IV patients. RESULTS: Compared with controls, EPT increased: (1) endurance time, with estimated treatment effect: +703 (95% CI: 379 to 1031) s, p=0.0008 (GOLD I-II); +390 (95% CI: 205 to 574) s, p=0.0006 (GOLD III-IV); (2) peak oxygen uptake (p=0.0086 in GOLD I-II; p=0.0004 in GOLD III-IV); (3) glottic dilatation ratio at maximum collapse on laryngoscopy in the submaximal exercise (p=0.0062 in GOLD I-II; p=0.0001 in GOLD III-IV); and (4) the inflection point of expiratory tidal volume relative to minute ventilation during the incremental exercise (p=0.0015 in GOLD I-II; p=0.0075 in GOLD III-IV). Across GOLD grades, the responses of glottic dilatation ratio at maximum collapse and the expiratory tidal volume at the inflection point were selected as more influential variables correlating with the improvement in peak oxygen uptake and endurance time, respectively. CONCLUSION: These results show that EPT improved aerobic capacity and endurance time with larger laryngeal widening and adequate ventilation despite advanced COPD. TRIAL REGISTRATION NUMBER: UMIN000041250.

Virulence of Mycobacterium intracellulare clinical strains in a mouse model of lung infection - role of neutrophilic inflammation in disease severity.

BACKGROUND: Mycobacterium intracellulare is a major etiological agent of Mycobacterium avium-intracellulare pulmonary disease (MAC-PD). However, the characteristics of the virulence of M. intracellulare and the in vivo chemotherapeutic efficacy remain unclear. In this study, we examined the virulence of nine M. intracellulare strains with different clinical phenotypes and genotypes in C57BL/6 mice. RESULTS: We classified three types of virulence phenotypes (high, intermediate, and low) based on the kinetics of the bacterial load, histological lung inflammation, and neutrophilic infiltration. High virulence strains showed more severe neutrophilic infiltration in the lungs than intermediate and low virulence strains, with 6.27-fold and 11.0-fold differences of the average percentage of neutrophils in bronchoalveolar lavage fluid, respectively. In particular, the high virulence strain M.i.198 showed the highest mortality in mice, which corresponded to the rapid progression of clinical disease. In mice infected with the drug-sensitive high virulence strain M019, clarithromycin-containing chemotherapy showed the highest efficacy. Monotherapy with rifampicin exacerbated lung inflammation with increased lymphocytic and neutrophilic infiltration into the lungs. CONCLUSIONS: The virulence phenotypes of clinical strains of M. intracellulare were diverse, with high virulence strains being associated with neutrophilic infiltration and disease progression in infected mice. These high virulence strains were proposed as a useful subject for in vivo chemotherapeutic experiments.

Characterization and cluster analyses of elderly asthma in comparison with nonelderly patients with asthma in Japan.

BACKGROUND: Asthma is a heterogeneous disease with multiple phenotypes that are useful in precision medicine. As the population ages, the elderly asthma (EA, aged ≥ 65 years) population is growing, and EA is now a major health problem worldwide. OBJECTIVE: To characterize EA and identify its phenotypes. METHODS: In adult patients with asthma (aged ≥ 18 years) who had been diagnosed with having asthma at least 1 year before study enrollment, 1925 were included in the NHOM-Asthma (registered in UMIN-CTR; UMIN000027776), and the data were used for this study, JFGE-Asthma (registered in UMIN-CTR; UMIN000036912). Data from EA and non-EA (NEA) groups were compared, and Ward's minimum-variance hierarchical clustering method and principal component analysis were performed. RESULTS: EA was characterized by older asthma onset, longer asthma duration and smoking history, more comorbidities, lower pulmonary function, less atopic, lower adherence, and more hospital admissions because of asthma. In contrast, the number of eosinophils, total immunoglobulin E level, oral corticosteroid use, and asthma control questionnaire scores were equivalent between EA and NEA. There were 3 distinct phenotypes in EA, which are as follows: EA1: youngest, late onset, short duration, mild; EA2: early onset, long duration, atopic, low lung function, moderate; and EA3: oldest, eosinophilic, overweight, low lung function, most severe. The classification factors of the EA phenotypes included the age of onset and asthma control questionnaire-6. Similarities were observed between EA and NEA phenotypes after principal component analysis. CONCLUSION: The EA in Japan may be unique because of the population's high longevity. Characterization of EA phenotypes from the present cohort indicated the need for distinct precision medicine for EA. TRIAL REGISTRATION: JFGE-Asthma registered in UMIN-CTR (https://www.umin.ac.jp/ctr/); UMIN000036912.

Nationwide survey of refractory asthma with bronchiectasis by inflammatory subtypes.

RATIONALE: Bronchiectasis and bronchiolitis are differential diagnoses of asthma; moreover, they are factors associated with worse asthma control. OBJECTIVE: We determined clinical courses of bronchiectasis/bronchiolitis-complicated asthma by inflammatory subtypes as well as factors affecting them. METHODS: We conducted a survey of refractory asthma with non-cystic fibrosis bronchiectasis/bronchiolitis in Japan. Cases were classified into three groups, based on the latest fractional exhaled NO (FeNO) level (32 ppb for the threshold) and blood eosinophil counts (320/µL for the threshold): high (type 2-high) or low (type 2-low) FeNO and eosinophil and high FeNO or eosinophil (type 2-intermediate). Clinical courses in groups and factors affecting them were analysed. RESULTS: In total, 216 cases from 81 facilities were reported, and 142 were stratified: 34, 40 and 68 into the type 2-high, -intermediate and -low groups, respectively. The frequency of bronchopneumonia and exacerbations requiring antibiotics and gram-negative bacteria detection rates were highest in the type 2-low group. Eighty-seven cases had paired latest and oldest available data of FeNO and eosinophil counts; they were analysed for inflammatory transition patterns. Among former type 2-high and -intermediate groups, 32% had recently transitioned to the -low group, to which relatively low FeNO in the past and oral corticosteroid use contributed. Lastly, in cases treated with moderate to high doses of inhaled corticosteroids, the frequencies of exacerbations requiring antibiotics were found to be higher in cases with more severe airway lesions and lower FeNO. CONCLUSIONS: Bronchiectasis/bronchiolitis-complicated refractory asthma is heterogeneous. In patients with sputum symptoms and low FeNO, airway colonisation of pathogenic bacteria and infectious episodes are common; thus, corticosteroids should be carefully used.

Comparative genomic analysis of Mycobacterium intracellulare: implications for clinical taxonomic classification in pulmonary Mycobacterium avium-intracellulare complex disease.

BACKGROUND: Mycobacterium intracellulare is a representative etiological agent of emerging pulmonary M. avium-intracellulare complex disease in the industrialized countries worldwide. The recent genome sequencing of clinical strains isolated from pulmonary M. avium-intracellulare complex disease has provided insight into the genomic characteristics of pathogenic mycobacteria, especially for M. avium; however, the genomic characteristics of M. intracellulare remain to be elucidated. RESULTS: In this study, we performed comparative genomic analysis of 55 M. intracellulare and related strains such as M. paraintracellulare (MP), M. indicus pranii (MIP) and M. yonogonense. Based on the average nucleotide identity, the clinical M. intracellulare strains were phylogenetically grouped in two clusters: (1) the typical M. intracellulare (TMI) group, including ATCC13950 and virulent M.i.27 and M.i.198 that we previously reported, and (2) the MP-MIP group. The alignment of the genomic regions was mostly preserved between groups. Plasmids were identified between groups and subgroups, including a plasmid common among some strains of the M.i.27 subgroup. Several genomic regions including those encoding factors involved in lipid metabolism (e.g., fadE3, fadE33), transporters (e.g., mce3), and type VII secretion system (genes of ESX-2 system) were shown to be hypermutated in the clinical strains. M. intracellulare was shown to be pan-genomic at the species and subspecies levels. The mce genes were specific to particular subspecies, suggesting that these genes may be helpful in discriminating virulence phenotypes between subspecies. CONCLUSIONS: Our data suggest that genomic diversity among M. intracellulare, M. paraintracellulare, M. indicus pranii and M. yonogonense remains at the subspecies or genovar levels and does not reach the species level. Genetic components such as mce genes revealed by the comparative genomic analysis could be the novel focus for further insight into the mechanism of human pathogenesis for M. intracellulare and related strains.

Characteristic chest CT findings for progressive cavities in Mycobacterium avium complex pulmonary disease: a retrospective cohort study.

BACKGROUND: Although cavities are an important finding in Mycobacterium avium complex pulmonary disease (MAC-PD), there is little information regarding the types of cavities that indicate disease progression. This study was performed to identify cavity characteristics that were associated with disease progression in patients with MAC-PD. METHODS: This retrospective cohort study included 97 patients presenting with MAC-PD with cavities between December 2006 and June 2016. We compared initial and final computed tomography (CT) findings, classified 52 and 45 patients in the progressive and non-progressive cavity groups, respectively, and examined the progression-related imaging features in initial CT images. A progressive cavity was defined by more than two-fold increase in internal diameter or emergence of a new cavity around the initial cavity. RESULTS: Patients in the progressive group were older (p < 0.001), had a lower body mass index (p = 0.043), and showed higher diabetes complication rates (p = 0.005). The initial CT in the progressive group showed a longer maximum internal diameter of the cavity (p < 0.001) and higher rates of cavities close to the chest wall (p < 0.001), multiple cavities (p = 0.023), consolidation around the cavity (p < 0.001), atelectasis (p = 0.011), and pleural thickening (p < 0.001). Multivariable logistic regression analysis revealed that the maximum internal diameter of the cavity (odds ratio [OR]: 1.11, 95% confidence interval [CI]: 1.02-1.21; p=0.012) and consolidation around the cavity (OR: 16.15, 95% CI: 4.05-64.46; p < 0.001) were significantly associated with progressive cavities. In cavities with a maximum internal diameter of ≥10 mm and simultaneous consolidation, the probability of progression was as high as 96.2%. The 10-year mortality rates in the progressive and non-progressive cavity groups were 46.7 and 9.8% (p < 0.001), respectively, while the 10-year respiratory failure rates were 28.1 and 0%, respectively (p < 0.001). CONCLUSIONS: Large cavity size and consolidation on CT showed strong relationships with disease progression, which led to respiratory failure and high mortality rate.

The impact of adjuvant surgical treatment of nontuberculous mycobacterial pulmonary disease on prognosis and outcome.

BACKGROUND: Lung resection in patients with nontuberculous mycobacterial pulmonary disease (NTM-PD) has been reported to be associated with favorable outcomes. However, little is known regarding the risk and prognostic factors for refractory and recurrent cases. We aimed to evaluate the overall impact and benefit of adjuvant lung surgery by comparing NTM-PD patients who underwent adjuvant lung resection with those treated exclusively with antibiotics. We also investigated the efficacy of serum IgA antibody against glycopeptidolipid (GPL) core antigen (GPL core antibody) to monitor disease activity and predict the recurrence of disease after adjuvant lung resection. METHODS: We retrospectively evaluated the clinical characteristics and surgical outcomes of 35 patients surgically treated for NTM-PD. Furthermore, we compared surgically treated patients and control patients treated exclusively with antibiotics who were matched statistically 1:1 using a propensity score calculated from age, sex, body mass index, and radiologic features of disease. RESULTS: In the surgically treated patients, the median age was 58 (interquartile range, 47-65) years and 65.7% were female. Twenty-eight patients had Mycobacterium avium complex. Operations comprised four pneumonectomies, two bilobectomies, one bilobectomy plus segmentectomy, 17 lobectomies, two segmentectomies, and nine lobectomies plus segmentectomies. Postoperative complications occurred in seven patients (20%), there were no operative deaths, and 33 (94.3%) patients achieved negative sputum culture conversion. Refractory and recurrent cases were associated with remnant bronchiectasis, contralateral shadows, and positive acid-fast bacilli staining or culture. Of 28 statistically matched pairs, long-term sustained negative culture conversion was observed in 23 (82.2%) surgical group patients and in 14 (50.0%) non-surgical group patients (0.0438). The mortality rate was lower in the surgical group, but did not reach statistical significance (one in the surgical group and four in the non-surgical group, p = 0.3516). GPL core antibody was correlated with disease activity and recurrence. CONCLUSIONS: NTM-PD patients who underwent adjuvant lung resection experienced overall favorable outcomes and achieved sputum culture conversion more frequently. Long-term mortality may have been reduced by this procedure, and the level of GPL core antibody was shown to be a good clinical indicator of disease activity after surgery.

Pulmonary disease caused by a newly identified mycobacterium: Mycolicibacterium toneyamachuris: a case report.

BACKGROUND: Non-tuberculous mycobacterial pulmonary disease (NTM-PD) is becoming a significant health burden. Recent advances in analysis techniques have allowed the accurate identification of previously unknown NTM species. Here, we report a case of NTM-PD caused by a newly identified mycobacteria in an immunocompetent patient. CASE PRESENTATION: A 44-year-old woman was referred to our hospital due to the frequent aggravation of her chronic respiratory symptoms, with NTM-PD-compatible computed tomography findings. Unidentified mycobacterium was repeatedly isolated from respiratory specimens and we diagnosed her as NTM-PD of unidentified mycobacterium. Subsequent whole-genome analysis revealed that the unidentified mycobacterium was a novel mycobacterium genetically close to Mycolicibacterium mucogenicum. We started combination therapy with clarithromycin, moxifloxacin, amikacin, and imipenem/cilastatin, referring to drug sensitivity test results and observed its effect on M. mucogenicum infection. Her symptoms and radiological findings improved significantly. CONCLUSION: We report a case of NTM-PD caused by a newly identified mycobacteria, Mycolicibacterium toneyamachuris, genetically close to M. mucogenicum. This pathogenic mycobacterium showed different characteristics from M. mucogenicum about clinical presentation and drug sensitivity. The clinical application of genomic sequencing will advance the identification and classification of pathogenic NTM species, and enhance our understanding of mycobacterial diseases.

Human airway trypsin-like protease enhances interleukin-8 synthesis in bronchial epithelial cells by activating protease-activated receptor 2.

Human airway trypsin-like protease (HAT) localizes at human bronchial epithelial cells (HBECs). HAT enhanced release of interleukin-8 (IL-8) from HBECs at 10-100 mU/mL and the enhanced release was almost completely abolished by 50 µM leupeptin, a serine protease inhibitor. Previous reports suggested that HAT displays its physiological functions via protease-activated receptor 2 (PAR2). In the present study, we examined the mechanism whereby HAT upregulates IL-8 synthesis in HBECs with a focus on PAR2. Northern blot analysis revealed that HAT enhanced IL-8 mRNA expression at concentrations of 10-100 mU/mL. PAR2 activating peptide (PAR2 AP) also enhanced IL-8 release and IL-8 mRNA expression in HBECs at 50-1,000 µM at similar levels as HAT. Knockdown of PAR2 mRNA by siRNA methods showed that PAR2 mRNA expression was significantly depressed in primary HBECs, and both HAT- and PAR2 AP-induced IL-8 mRNA elevation was significantly depressed in PAR2 siRNA-transfected HBECs. Additionally, HAT cleaved the PAR2 activating site (R36-S37 bond) of synthetic PAR2 N-terminal peptide. These results indicate that HAT stimulates IL-8 synthesis in airway epithelial cells via PAR2 and could help to amplify inflammation in chronic respiratory tract disease.

Serum antibody profiles in individuals with latent Mycobacterium tuberculosis infection.

One-third of the world's humans has latent tuberculosis infection (LTBI), representing a large pool of potentially active TB. Recent LTBI carries a higher risk of disease progression than remote LTBI. Recent studies suggest important roles of antibodies in TB pathology, prompting us to investigate serum antibody profiles in a cohort with LTBI. In this single-center prospective observational study, we analyzed IgG-antibody concentrations against five major Mycobacterium tuberculosis (Mtb) antigens (including 6 kDa early secretory antigenic target (ESAT6), CFP10, and antigen 85A, which are expressed mainly in the growth phase; and mycobacterial DNA-binding protein 1 (MDP1) and alpha-crystallin like protein (Acr), which are expressed in the dormant phases) in individuals with recent (n=13) or remote (n=12) LTBI, no Mtb infection (n=19), or active TB (n=15). Antibody titers against ESAT6 and MDP1 were significantly higher in individuals with recent LTBI than in those with no Mtb infection or remote LTBI. All pairwise antibody titers against these five major antigens were significantly correlated throughout the stages of Mtb infection. Five individuals with recent LTBI had significantly higher antibody titers against ESAT6 (P = 0.03), Ag85A (P = 0.048), Acr (P = 0.057), and MDP1 (P = 0.0001) than in individuals with remote LTBI; they were also outside the normal range (+2 SDs). One of these individuals was diagnosed with active pulmonary TB at 18-month follow-up examination. These findings indicated that concentrations of antibodies against both multiplying and dormant Mtb are higher in recent LTBI and that individuals with markedly higher antibody titers may be appropriate candidates for prophylactic therapy.

The association between erythromycin monotherapy for Mycobacterium avium complex lung disease and cross-resistance to clarithromycin: A retrospective case-series study.

Long-term, low-dose erythromycin monotherapy, based on the anti-inflammatory effects of macrolides, has been reported to have the potential to suppress the exacerbation of Mycobacterium avium complex (MAC) lung disease with less toxicity. It remains unclear whether erythromycin monotherapy induces cross-resistance to clarithromycin, a key drug for MAC. To clarify this point, we conducted a retrospective, single-center, case-series study on patients with MAC lung disease who underwent erythromycin monotherapy for at least 6 months. Drug susceptibility tests, before and after erythromycin treatment initiation, were analyzed. Thirty-three patients were included in our study. All 33 patients showed susceptibility to clarithromycin for MAC both before and after erythromycin monotherapy. There was no significant difference in clarithromycin minimum inhibitory concentrations between before and after erythromycin treatment (median difference = 0 µg/ml; P = .313, Wilcoxon's signed-rank test). We conclude that erythromycin monotherapy for MAC lung disease may not induce cross-resistance to clarithromycin.

Levels of Antibody against Glycopeptidolipid Core as a Marker for Monitoring Treatment Response in Mycobacterium avium Complex Pulmonary Disease: a Prospective Cohort Study.

The diagnosis of Mycobacterium avium complex pulmonary disease (MAC-PD) is sometimes complicated and time-consuming. A serodiagnostic kit that measures the serum levels of IgA antibodies against the glycopeptidolipid (GPL) core is commercially available and has good diagnostic accuracy for MAC-PD. However, the significance of measurement of GPL core IgA antibody levels in monitoring for chemotherapy response in patients with MAC-PD was not well investigated. Thirty-four treatment naive MAC-PD patients who were started on multidrug chemotherapy were enrolled. Their antibody levels were prospectively measured at regular intervals. The relationships between their antibody levels and the therapeutic outcomes were examined. The patients were classified into three groups (conversion, recurrence, and nonconversion) based on the bacteriological outcomes after chemotherapy. There were no significant differences in the antibody levels before treatment between the culture conversion (n = 19), recurrence (n = 7), and nonconversion (n = 8) groups (P = 0.9881). The levels decreased significantly after the chemotherapy (P < 0.0001). Recurrence and/or worsening of chest radiography findings were observed in cases whose antibody levels subsequently increased after cessation of the chemotherapy. No significant difference in the percent decrease in antibody levels by the chemotherapy was observed between the culture conversion and recurrence groups (P = 0.9338). The initial antibody levels are not a predictor of therapeutic outcomes, and also the percent decrease in antibody levels is not a sufficient indicator of the cessation of chemotherapy. However, serial measurements of antibody levels may allow objective monitoring of disease activity in individual MAC-PD patients.

Identification of three exercise-induced mortality risk factors in patients with COPD.

The survival rate of chronic obstructive pulmonary disease (COPD) patients with severely reduced exercise capacity is extremely low. We recently identified three life-threatening pathophysiological conditions during cardiopulmonary exercise testing (CPET): (1) exercise-induced hypoxemia, (2) sympathetic overactivity, and (3) progressive respiratory acidosis at low-intensity exercise. The present prospective observation study aimed to determine whether these parameters constitute risk factors of mortality in moderate-to-very severe COPD. Ninety-six COPD patients were followed-up, monthly, for >3 years. Subsequently, spirometry and CPET were performed to examine parameters of exercise-induced hypoxemia ([PaO2 slope, mmHg/L · min(-1)] = Decrease in PaO2/ΔV˙ O2 (Difference in ΔV˙ O2 between at rest and at peak exercise)), progression of acidosis ([ΔpH/ΔV˙ O2,/L · min(-1)] = Decrease in pH/ΔV˙ O2), and sympathetic overactivity ([Δnorepinephrine (NE)/ΔV˙ O2, ng/mL/L · min(-1)] = Increase in NE/ΔV˙ O2). Univariate analysis revealed a significant association between the three conditions with increased mortality. Kaplan-Meier analysis showed that the quartile combining the steepest PaO2 slope (≤-55 mmHg/ΔV˙ O2 [L/min]), steepest decrease in arterial blood pH (≤ -1.72/ΔV˙ O2 [L/min]), and most rapid increase in plasma NE level (≥ 5.2 ng/VO2 [L/min]) during incremental exercise was associated with higher all-cause mortality. These conditions showed cumulative effects on COPD patients' survival. Multivariate analyses revealed that these three life-threatening factors are also independent predictors of mortality based on age, heart rate and PaO2 at rest, body mass index, and forced expiratory volume in 1 s. Thus, these new exercise-induced mortality risk factors may lead to more efficient pulmonary rehabilitation programs for COPD patients based on patient-specific exercise-induced pathophysiological profiles.

Effects of ghrelin treatment on exercise capacity in underweight COPD patients: a substudy of a multicenter, randomized, double-blind, placebo-controlled trial of ghrelin treatment.

BACKGROUND: The aim of this substudy of the ghrelin treatment, multicenter, randomized, double-blind, placebo-controlled trial was to investigate the effects of ghrelin administration on exercise capacity and the underlying mechanisms in underweight patients with chronic obstructive pulmonary disease (COPD) using cardiopulmonary exercise testing. METHODS: Twenty underweight COPD patients were randomized to pulmonary rehabilitation with intravenous ghrelin (2 µg/kg, n = 10) or placebo (n = 10) twice daily for 3 weeks in a double-blind fashion. The primary outcome was changes in peak oxygen uptake V•o2. Secondary outcomes included changes in exertional cardio-respiratory functions: O2-pulse, physiologic dead space/tidal volume-ratio (VD/VT), ventilatory equivalent for oxygen V•E/V•o2, and ventilatory equivalent for carbon dioxide V•E/V•co2. RESULTS: With incremental exercise, at peak exercise, there was a significant difference in the mean difference (ghrelin minus placebo), i.e., treatment effect in: i) peak V•o2 (1.2 mL/kg/min, 95% CI: 0.2-2.3 mL/kg/min, between-group p = 0.025); ii) V•E/V•o2 (-4.2, 95% CI: -7.9 to -0.5, between-group p = 0.030); iii) V•E/V•co2 (-4.1, 95% CI: -8.2 to -0.1, between-group p = 0.045); iv) VD/VT (-0.04, 95% CI: -0.08 to -0.00, between-group p = 0.041); and v) O2-pulse (0.7 mL/beat, 95% CI: 0.3 to 1.2 mL/beat, between-group p = 0.003). Additionally, repeated-measures analysis of variance (ANOVA) indicated a significant time-course effect of ghrelin versus placebo in the peak V•o2 (p = 0.025). CONCLUSION: Ghrelin administration was associated with improved exertional capacity and improvements in ventilatory-cardiac parameters. TRIAL REGISTRATION: UMIN (University Hospital Medical Information Network in Japan) C000000061.

Effects of oxygen on exertional dyspnoea and exercise performance in patients with chronic obstructive pulmonary disease.

BACKGROUND AND OBJECTIVE: The results of studies on the oxygen response in patients with COPD should provide important clues to the pathophysiology of exertional dyspnoea. We investigated the exercise responses to hyperoxia in relation to dyspnoea profile, as well as cardiopulmonary, acidotic and sympathetic parameters in 35 patients with stable COPD (mean FEV(1) 46% predicted). METHODS: This was a single-blind trial, in which patients breathed 24% O(2) or compressed air (CA) in random order during two incremental cycle exercise tests. RESULTS: PaO(2) and PaCO(2) were higher (P < 0.0001 and P < 0.05, respectively) at each exercise point while patients were breathing 24% O(2) compared with CA. At a standardized time point near peak exercise, use of O(2) resulted in reduced plasma lactate and plasma noradrenaline concentrations (P < 0.01). Peak minute ventilation/indirect maximum voluntary ventilation was similar while breathing 24% O(2) and CA. At peak exercise, the dyspnoea score, pH and plasma noradrenaline concentrations were similar while breathing 24% O(2) and CA. The dyspnoea-ratio (%) of Δoxygen uptake (peak minus resting oxygen uptake) curve reached a break point that occurred at a similar exercise point while breathing 24% O(2) or CA. CONCLUSIONS: Regardless of whether they breathed CA or 24% O(2) , patients with COPD did not develop ventilatory compensation for exertional acidosis, and the pH values measured were similar. Hyperoxia during a standardized exercise protocol did not alter the pattern of exertional dyspnoea in these patients, compared with breathing CA, although hyperoxia resulted in miscellaneous effects.

Long-Term Prognosis and Antimycobacterial Glycolipid Antibody as Biomarker in Mycobacterium avium-intracellulare Complex Pulmonary Disease.

Clinical characteristics and outcomes of multidrug chemotherapy have been used as the main prognostic factors for Mycobacterium avium-intracellulare complex pulmonary disease (MAC-PD) over the last decade; however, no useful prognostic biomarkers have been reported. The aim is to ascertain whether the serum antibody titers could include useful prognostic predictors of MAC-PD. Ninety-four patients with MAC-PD were enrolled and regularly followed up with for more than 5 years or until death. Cox proportional hazard regression and receiver operating characteristic (ROC) curve analyses were used to identify predictors of mortality in this prospective observational study. According to treatment outcomes, 85 patients completed follow-up and were classified into four groups. Seventeen patients (20%) died during follow-up (median, 10.1 years; interquartile range, 8.1 to 12.4 years). All 11 patients with MAC-PD-specific death were included in the 14 patients of the group nonresponsive to the multidrug chemotherapy. They had significantly higher anti-Mycobacterium glycolipid (MBGL) antibody titers than those in the other groups and a significantly (P < 0.0001) poorer survival prognosis. The anti-MBGL antibody titers also served as a negative prognostic factor. A cutoff score of 7, which was calculated by clinical poor prognostic characteristics and anti-MBGL antibody titers, differentiated the nonresponse group and the other groups at baseline (sensitivity, specificity, and area under the curve: 92.9%, 81.7%, and 0.95, respectively). In conclusion, anti-MBGL antibody titers were useful to assess the refractory MAC-PD. The predictions of treatment outcome and mortality become more accurate by using anti-MBGL antibody and clinical poor prognostic characteristics together. IMPORTANCE The natural history of MAC-PD is challenging to predict in immunocompetent patients at diagnosis, and the current multidrug chemotherapy options are not strong enough to eliminate mycobacteria from the lungs. Therefore, the diagnosis of MAC-PD does not necessarily lead to the decision to start chemotherapy. We have also observed refractory patients in clinical practice, who were resistant to multiple-drug chemotherapy and showed persistent excretion of MAC bacilli and progressive worsening of chest radiographic findings until death. We have reported that the measurements of anti-MBGL antibody titers helped assess refractory MAC-PD in this study. Furthermore, the predictions of treatment outcome and mortality become more accurate by using the anti-MBGL antibody in addition to clinical poor prognostic characteristics, which were older age, lower body mass index, the positive results of a smear test for acid-fast bacteria (AFB), and presence of cavitary disease.

Increased Oxygen Extraction by Pulmonary Rehabilitation Improves Exercise Tolerance and Ventilatory Efficiency in Advanced Chronic Obstructive Pulmonary Disease.

BACKGROUND: In cardiopulmonary exercise testing (CPET), oxygen uptake (V'O2) is calculated using the product of minute ventilation (V'E) and the difference between inspiratory and expiratory O2 concentrations (ΔFO2). However, little is known about the response of ΔFO2 to pulmonary rehabilitation (PR). The aim of the present study was (1) to investigate whether PR increases peak V'O2, based on whether ΔFO2 or V'E at peak exercise increase after PR, and (2) to investigate whether an improvement in ΔFO2 correlates with an improvement in ventilatory efficiency. METHODS: A total of 38 patients with severe and very severe COPD, whose PR responses were evaluated by CPET, were retrospectively analyzed. RESULTS: After PR, peak V'O2 was increased in 14 patients. The difference in ΔFO2 at peak exercise following PR correlated with the difference in peak V'O2 (r = 0.4884, p = 0.0019), the difference in V'E/V'CO2-nadir (r = -0.7057, p < 0.0001), and the difference in V'E-V'CO2 slope (r = -0.4578, p = 0.0039), but it did not correlate with the difference in peak V'E. CONCLUSIONS: The increased O2 extraction following PR correlated with improved exercise tolerance and ventilatory efficiency. In advanced COPD patients, a new strategy for improving O2 extraction ability might be effective in those in whom ventilatory ability can be only minimally increased.

Direct Attachment with Erythrocytes Augments Extracellular Growth of Pathogenic Mycobacteria.

Pathogenic intracellular mycobacteria, such as Mycobacterium tuberculosis and Mycobacterium avium, which cause lung diseases, can grow in macrophages. Extracellular mycobacteria have been reported in the lungs, blood, and sputum of patients, indicating the involvement of these pathogens in disease progression. Erythrocytes are involved in the symptoms associated with pulmonary mycobacterial diseases, such as bloody sputum and hemoptysis; however, little attention has been paid to the role of erythrocytes in mycobacterial diseases. Herein, we found that Mycobacterium avium subsp. hominissuis (MAH) and Mycobacterium intracellulare colocalized with erythrocytes at the sites of lung infection, inside capillaries and necrotic areas of granulomas, using histopathological examinations. Electron microscopy showed that MAH adhered and entered human erythrocytes when they were cocultured in vitro. MAH adhered to erythrocytes through complement receptor 1 and cell-surface sialo-glycoproteins. Importantly, MAH grew vigorously without causing any pronounced damage to erythrocytes. This erythrocyte-mediated enhancement of MAH growth occurred extracellularly depending on its direct attachment to erythrocytes. In contrast, MAH failed to multiply inside erythrocytes. Similarly, erythrocytes augmented the growth of other pathogenic mycobacteria, such as M. intracellulare and M. tuberculosis. THP-1 cell-derived human macrophages preferentially phagocytosed erythrocytes that were attached to mycobacteria (compared to bacteria alone), suggesting that erythrocyte-attached mycobacteria are an efficient infectious source for macrophages. Our findings provide new insights into the pathogenesis of mycobacterial diseases and offer an alternative and useful strategy for treating mycobacterial disease. IMPORTANCE Pathogenic mycobacteria, such as Mycobacterium tuberculosis, Mycobacterium avium subsp. hominissuis (MAH), and Mycobacterium intracellulare, cause pulmonary infections as intracellular parasites of lung macrophages and epithelial cells. Here, using histopathological examinations we found that MAH and M. intracellulare colocalized with erythrocytes in lung infection sites. Subsequent studies demonstrated that direct interaction with erythrocytes enhances the extracellular proliferation of mycobacteria based on the following results: 1. MAH adhered and invaded human erythrocytes upon coculture in vitro; 2. MAH adhered to erythrocytes through complement receptor 1 and cell-surface sialo-glycoproteins; 3. MAH rapidly proliferated when directly attached to erythrocytes but not within them; 4. other mycobacteria, such as M. intracellulare and M. tuberculosis, also proliferated in the same way as MAH. The finding that pathogenic mycobacteria grow extracellularly in an erythrocyte-dependent manner is of considerable clinical importance for understanding disease progression and latent infection.

Impact of bronchial wall thickness on airflow obstruction in bronchiectasis.

The association between airflow obstruction and bronchial dilation has been researched in bronchiectasis. However, the impact of bronchial wall thickening on airflow obstruction has not been thoroughly investigated. This study assessed the underlying mechanism of airflow obstruction in bronchiectasis due to abnormal bronchial wall thickening using oscillometry. A total of 98 patients with bronchiectasis were retrospectively reviewed. At the time of diagnosis, spirometric and oscillometric parameters, high-resolution computed tomography scores, and clinical characteristics were collected. The bronchial diameter, bronchial wall thickness, and extent of emphysema were evaluated semi-quantitatively. Correlations between patient data and characteristics were analyzed. Thirty-three patients with airflow obstruction showed higher respiratory resistance, more negative respiratory reactance (Xrs) at 5 Hz (X5), and higher bronchial wall thickness score than those without airflow obstruction. The bronchial wall thickness score negatively affected forced expiration volume in 1 s /forced vital capacity and X5. Abnormal bronchial wall thickening might make Xrs more negative and progress airflow obstruction in bronchiectasis.