Antibacterial activity of high-dose nitric oxide against pulmonary Mycobacterium abscessus disease.

INTRODUCTION: Mycobacterium abscessus is an emerging pulmonary pathogen with limited treatment options. Nitric oxide (NO) demonstrates antibacterial activity against various bacterial species, including mycobacteria. In this study, we evaluated the effect of adjunctive inhaled NO therapy, using a novel NO generator, in a CF patient with pulmonary M. abscessus disease, and examined heterogeneity of response to NO in vitro. METHODS: In the compassionate-use treatment, a 24-year-old CF patient with pulmonary M. abscessus was treated with two courses of adjunctive intermittent NO, first at 160 p.p.m. for 21 days and subsequently by escalating the dose up to 240 p.p.m. for 8 days. Methemoglobin, pulmonary function, 6 min walk distance (6MWD), qualify of life and sputum microbiology were assessed. In vitro susceptibility tests were performed against patient's isolate and comparison clinical isolates and quantified by Hill's slopes calculated from time-kill curves. RESULTS: M. abscessus lung infection eradication was not achieved, but improvements in selected qualify of life domains, lung function and 6MWD were observed during the study. Inhaled NO was well tolerated at 160 p.p.m. Dosing at 240 p.p.m. was stopped due to adverse symptoms, although methemoglobin levels remained within safety thresholds. In vitro susceptibility tests showed a dose-dependent NO effect on M. abscessus susceptibility and significant heterogeneity in response between M. abscessus clinical isolates. The patient's isolate was found to be the least susceptible strain in vitro. CONCLUSION: These results demonstrate heterogeneity in M. abscessus susceptibility to NO and suggest that longer treatment regimens could be required to see the reduction or eradication of more resistant pulmonary strains.

Early effects of roflumilast on insulin sensitivity in adults with prediabetes and overweight/obesity involve age-associated fat mass loss - results of an exploratory study.

PURPOSE: Roflumilast (Daliresp, Daxas) is a FDA-approved phosphodiesterase 4 (PDE4) inhibitor for the treatment of moderate-to-severe chronic obstructive pulmonary disease. In mice and in limited human studies, this oral medication can cause weight loss and improve insulin sensitivity. We set out to determine the mechanism of its effect on insulin sensitivity. PATIENTS AND METHODS: Eight adults with overweight/obesity and prediabetes received roflumilast for 6 weeks. Before and after roflumilast, subjects underwent tests of insulin sensitivity, mixed meal test, body composition, markers of inflammation, and mitochondria function. Dietary intake and physical activity were also assessed. Our primary outcome was the change in peripheral insulin sensitivity, as assessed by the hyper-insulinemic euglycemic clamp. RESULTS: This study was underpowered for the primary outcome. Pre- and post-roflumilast mean peripheral insulin sensitivity were 48.7 and 70.0 mg/g fat free mass/minute, respectively, (P-value=0.18), respectively. Among the mixed meal variables, roflumilast altered glucagon-like peptide 1 (GLP-1) hormone the most, although the average effect was not statistically significant (P=0.18). Roflumilast induced a trend toward significance in 1) decreased energy intake (from 11,095 KJ to 8,4555 KJ, P=0.07), 2) decreased fat mass (from 34.53 to 32.97 kg, P=0.06), 3) decreased total and LDL cholesterol (P=0.06 for both variables), and 4) increased plasma free fatty acids (from 0.40 to 0.50 mEq/L, P=0.09) The interval changes in adiposity and free fatty acid were significantly associated with the subject's age (P-value range= <0.001 to 0.02 for the correlations). Inflammatory and adhesion markers, though unchanged, significantly correlated with one another and with incretin hormones only after roflumilast. CONCLUSION: We demonstrate, for the first time in humans, increasing percentage of fat mass loss from roflumilast with increasing age in adults with prediabetes and overweight/obesity. We also demonstrate novel associations among roflumilast-induced changes in incretin hormones, inflammatory markers, peripheral insulin sensitivity, and adiposity. We conclude that roflumilast's early effects on insulin sensitivity is indirect and likely mediated through roflumilast's prioritization of lipid over glucose handling. CLINICAL TRIALS REGISTRATION: NCT01862029.

Abnormal lymphangiogenesis in idiopathic pulmonary fibrosis with insights into cellular and molecular mechanisms.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, debilitating respiratory disease whose pathogenesis is poorly understood. In IPF, the lung parenchyma undergoes extensive remodeling. We hypothesized that lymphangiogenesis is part of lung remodeling and sought to characterize pathways leading to lymphangiogenesis in IPF. We found that the diameter of lymphatic vessels in alveolar spaces in IPF lung tissue correlated with disease severity, suggesting that the alveolar microenvironment plays a role in the lymphangiogenic process. In bronchoalveolar lavage fluid (BALF) from subjects with IPF, we found short-fragment hyaluronic acid, which induced migration and proliferation of lymphatic endothelial cells (LECs), processes required for lymphatic vessel formation. To determine the origin of LECs in IPF, we isolated macrophages from the alveolar spaces; CD11b(+) macrophages from subjects with IPF, but not those from healthy volunteers, formed lymphatic-like vessels in vitro. Our findings demonstrate that in the alveolar microenvironment of IPF, soluble factors such as short-fragment hyaluronic acid and cells such as CD11b(+) macrophages contribute to lymphangiogenesis. These results improve our understanding of lymphangiogenesis and tissue remodeling in IPF and perhaps other fibrotic diseases as well.

MMP1 and MMP7 as potential peripheral blood biomarkers in idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a chronic progressive fibrotic lung disease associated with substantial morbidity and mortality. The objective of this study was to determine whether there is a peripheral blood protein signature in IPF and whether components of this signature may serve as biomarkers for disease presence and progression. METHODS AND FINDINGS: We analyzed the concentrations of 49 proteins in the plasma of 74 patients with IPF and in the plasma of 53 control individuals. We identified a combinatorial signature of five proteins-MMP7, MMP1, MMP8, IGFBP1, and TNFRSF1A-that was sufficient to distinguish patients from controls with a sensitivity of 98.6% (95% confidence interval [CI] 92.7%-100%) and specificity of 98.1% (95% CI 89.9%-100%). Increases in MMP1 and MMP7 were also observed in lung tissue and bronchoalveolar lavage fluid obtained from IPF patients. MMP7 and MMP1 plasma concentrations were not increased in patients with chronic obstructive pulmonary disease or sarcoidosis and distinguished IPF compared to subacute/chronic hypersensitivity pneumonitis, a disease that may mimic IPF, with a sensitivity of 96.3% (95% CI 81.0%-100%) and specificity of 87.2% (95% CI 72.6%-95.7%). We verified our results in an independent validation cohort composed of patients with IPF, familial pulmonary fibrosis, subclinical interstitial lung disease (ILD), as well as with control individuals. MMP7 and MMP1 concentrations were significantly higher in IPF patients compared to controls in this cohort. Furthermore, MMP7 concentrations were elevated in patients with subclinical ILD and negatively correlated with percent predicted forced vital capacity (FVC%) and percent predicted carbon monoxide diffusing capacity (DLCO%). CONCLUSIONS: Our experiments provide the first evidence for a peripheral blood protein signature in IPF to our knowledge. The two main components of this signature, MMP7 and MMP1, are overexpressed in the lung microenvironment and distinguish IPF from other chronic lung diseases. Additionally, increased MMP7 concentration may be indicative of asymptomatic ILD and reflect disease progression.

Progressive preclinical interstitial lung disease in rheumatoid arthritis.

BACKGROUND: Early detection and treatment for interstitial lung disease (ILD) in patients with rheumatoid arthritis (RA) may ameliorate disease progression. The objective of this study was to identify asymptomatic lung disease and potential therapeutic targets in patients having RA and preclinical ILD (RA-ILD). METHODS: Sixty-four adults with RA and 10 adults with RA and pulmonary fibrosis (RAPF) were referred to the National Institutes of Health, Bethesda, Maryland, and underwent high-resolution computed tomography (HRCT) and pulmonary physiology testing. Proteins capable of modulating fibrosis were quantified in alveolar fluid. RESULTS: Twenty-one of 64 patients (33%) having RA without dyspnea or cough had preclinical ILD identified by HRCT. Compared with patients without lung disease, patients with RA-ILD had statistically significantly longer histories of cigarette smoking (P< .001), increased frequencies of crackles (P= .02), higher alveolar-arterial oxygen gradients (P= .004), and higher HRCT scores (P< .001). The HRCT abnormalities progressed in 12 of 21 patients (57%) with RA-ILD. The alveolar concentrations of platelet-derived growth factor-AB and platelet-derived growth factor-BB were statistically significantly higher in patients having RA-ILD (mean [SE], 497.3 [78.6] and 1473 [264] pg/mL, respectively) than in patients having RA without ILD (mean [SE], 24.9 [42.4] and 792.7 [195.0] pg/mL, respectively) (P< .001 and P=.047, respectively). The concentrations of interferon gamma and transforming growth factor beta(2) were statistically significantly lower in patients having RAPF (mean [SE], 5.59 [1.11] pg/mL and 0.94 [0.46] ng/mL, respectively) than in patients having RA without ILD (mean [SE], 14.1 [1.9] pg/mL and 2.30 [0.39] ng/mL, respectively) (P=.001 and P=.006, respectively) or with preclinical ILD (mean [SD], 11.4 [2.6] pg/mL and 3.63 [0.66] ng/mL, respectively) (P=.04 and P=.007, respectively). Compared with patients having stable RA-ILD, patients having progressive RA-ILD had statistically significantly higher frequencies of treatment using methotrexate and higher alveolar concentrations of interferon gamma and transforming growth factor beta(1) (P=.046, P=.04, and P=.04, respectively). CONCLUSIONS: Asymptomatic preclinical ILD, which is detectable by HRCT, may be prevalent and progressive among patients having RA. Cigarette smoking seems to be associated with preclinical ILD in patients having RA, and treatment using methotrexate may be a risk factor for progression of preclinical ILD. Quantification of alveolar proteins indicates that potential pathogenic mechanisms seem to differ in patients having RA-ILD and symptomatic RAPF.

Early interstitial lung disease in familial pulmonary fibrosis.

RATIONALE: Identification of early, asymptomatic interstitial lung disease (ILD) in populations at risk of developing idiopathic pulmonary fibrosis (IPF) may improve the understanding of the natural history of IPF. OBJECTIVES: To determine clinical, radiographic, physiologic, and pathologic features of asymptomatic ILD in family members of patients with familial IPF. METHODS: One hundred sixty-four subjects from 18 kindreds affected with familial IPF were evaluated for ILD. Bronchoalveolar lavage fluid cells were analyzed using flow cytometry. Lung biopsies were performed in six subjects with asymptomatic ILD. MEASUREMENTS AND MAIN RESULTS: High-resolution computed tomography abnormalities suggesting ILD were identified in 31 (22%) of 143 asymptomatic subjects. Subjects with asymptomatic ILD were significantly younger than subjects with known familial IPF (P < 0.001) and significantly older than related subjects without lung disease (P < 0.001). A history of smoking was identified in 45% of subjects with asymptomatic ILD and in 67% of subjects with familial IPF; these percentages were significantly higher than that of related subjects without lung disease (23%) (P = 0.02 and P < 0.001, respectively). Percentages of activated CD4(+) lymphocytes were significantly higher in bronchoalveolar lavage fluid cells from subjects with asymptomatic ILD compared with related subjects without lung disease (P < 0.001). Lung biopsies performed in subjects with asymptomatic ILD revealed diverse histologic subtypes. CONCLUSIONS: Asymptomatic ILD in individuals at risk of developing familial IPF can be identified using high-resolution computed tomography scan of the chest, especially in those with a history of smoking. Lung biopsies from individuals in this cohort with early asymptomatic lung disease demonstrate various histologic subtypes of ILD.

Impairment of alveolar macrophage transcription in idiopathic pulmonary fibrosis.

RATIONALE: Alveolar macrophages are inflammatory cells that may contribute to the pathogenesis of idiopathic pulmonary fibrosis (IPF), which is characterized by excessive alveolar aggregation of cells and extracellular matrix proteins. OBJECTIVES: To identify potential molecular mechanisms of IPF. METHODS: To examine large-scale gene expression, messenger RNA isolated from alveolar macrophages and peripheral blood mononuclear cells from subjects with IPF and normal volunteers was hybridized to cDNA filters. MEASUREMENTS AND MAIN RESULTS: We showed that in IPF there is global down-regulation of gene expression in alveolar macrophages but not in blood monocytes. Nuclear run-on and pulse-chase studies showed that alveolar macrophages had significantly reduced transcription (p < 0.01). No significant difference in RNA degradation was found between subjects with IPF and normal volunteers. Western blot analyses revealed that concentrations of transcription factor II-H, a general transcription factor, were significantly lower in alveolar macrophages from subjects with IPF than in those from normal volunteers (p = 0.012). CONCLUSIONS: Impaired transcription in IPF is associated with decreased concentrations of transcription factor II-H in alveolar macrophages and may alter the intraalveolar milieu in IPF.