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RationaleCongenital Central Hypoventilation Syndrome (CCHS) is characterized by life-threatening sleep hypoventilation, and is caused by PHOX2B gene mutations, most frequently the PHOX2B27Ala/+ mutation, with patients requiring lifelong ventilatory support. It is unclear whether obstructive apneas are part of the syndrome.ObjectivesTo determine whether Phox2b27Ala/+ mice, which present the main symptoms of CCHS and die within hours after birth, also express obstructive apneas, and to investigate potential underlying mechanisms.MethodsApneas were classified as central, obstructive or mixed by using a novel system combining pneumotachography and laser detection of abdominal movement immediately after birth. Several respiratory nuclei involved in airway patency were examined by immunohistochemistry and electrophysiology in brainstem-spinal cord preparation.Measurements and Main ResultsThe median (interquartile range) of obstructive apnea frequency was 2.3/min (1.5-3.3) in Phox2b27Ala/+ pups versus 0.6/min (0.4-1.0) in wildtypes (P < 0.0001). Obstructive apnea duration was 2.7s (2.3-3.9) in Phox2b27Ala/+ pups versus 1.7s (1.1-1.9) in wildtypes (P < 0.0001). Central and mixed apneas presented similar, significant differences. In Phox2b27Ala/+ preparations, the hypoglossal nucleus had fewer (P < 0.05) and smaller (P < 0.01) neurons, compared to wildtypes. Importantly, coordination of phrenic and hypoglossal motor activities was disrupted, as evidenced by the longer and variable delay of hypoglossal with respect to phrenic activity onset (P < 0.001).ConclusionsThe Phox2b27Ala/+ mutation predisposed pups not only to hypoventilation and central apneas, but also to obstructive and mixed apneas, likely due to hypoglossal dysgenesis. These results thus demand attention towards obstructive events in infants with CCHS.

Rationale: Obstructive sleep apnea is recurrent upper airway obstruction caused by a loss of upper airway muscle tone during sleep. The main goal of our study was to determine if designer receptors exclusively activated by designer drugs (DREADD) could be used to activate the genioglossus muscle as a potential novel treatment strategy for sleep apnea. We have previously shown that the prototypical DREADD ligand clozapine-N-oxide increased pharyngeal diameter in mice expressing DREADD in the hypoglossal nucleus. However, the need for direct brainstem viral injections and clozapine-N-oxide toxicity diminished translational potential of this approach, and breathing during sleep was not examined.Objectives: Here, we took advantage of our model of sleep-disordered breathing in diet-induced obese mice, retrograde properties of the adeno-associated virus serotype 9 (AAV9) viral vector, and the novel DREADD ligand J60.Methods: We administered AAV9-hSyn-hM3(Gq)-mCherry or control AAV9 into the genioglossus muscle of diet-induced obese mice and examined the effect of J60 on genioglossus activity, pharyngeal patency, and breathing during sleep.Measurements and Main Results: Compared with control, J60 increased genioglossus tonic activity by greater than sixfold and tongue uptake of 2-deoxy-2-[18F]fluoro-d-glucose by 1.5-fold. J60 increased pharyngeal patency and relieved upper airway obstruction during non-REM sleep.Conclusions: We conclude that following intralingual administration of AAV9-DREADD, J60 can activate the genioglossus muscle and improve pharyngeal patency and breathing during sleep.

Rationale: There is an aspiration to retain increasing numbers of older workers in employment, and strategies to achieve this need to make provision for the increasing prevalence of chronic disease...

Rationale: Leptin treats upper airway obstruction and alveolar hypoventilation in leptin-deficient ob/ob mice. However, obese humans and mice with diet-induced obesity (DIO) are resistant to leptin because of poor permeability of the blood–brain barrier. We propose that intranasal leptin will bypass leptin resistance and treat sleep-disordered breathing in obesity. Objectives: To assess if intranasal leptin can treat obesity hypoventilation and upper airway obstruction during sleep in mice with DIO. Methods: Male C57BL/6J mice were fed with a high-fat diet for 16 weeks. A single dose of leptin (0.4 mg/kg) or BSA (vehicle) were administered intranasally or intraperitoneally, followed by either sleep studies (n = 10) or energy expenditure measurements (n = 10). A subset of mice was treated with leptin daily for 14 days for metabolic outcomes (n = 20). In a separate experiment, retrograde viral tracers were used to examine connections between leptin receptors and respiratory motoneurons. Measurements and Main Results: Acute intranasal, but not intraperitoneal, leptin decreased the number of oxygen desaturation events in REM sleep, and increased ventilation in non-REM and REM sleep, independently of metabolic effects. Chronic intranasal leptin decreased food intake and body weight, whereas intraperitoneal leptin had no effect. Intranasal leptin induced signal transducer and activator of transcription 3 phosphorylation in hypothalamic and medullary centers, whereas intraperitoneal leptin had no effect. Leptin receptor–positive cells were synaptically connected to respiratory motoneurons. Conclusions: In mice with DIO, intranasal leptin bypassed leptin resistance and significantly attenuated sleep-disordered breathing independently of body weight.

Classical interpretation of cystic fibrosis (CF) lung disease pathogenesis suggests that infection initiates disease progression, leading to an exuberant inflammatory response, excessive mucus, and ultimately bronchiectasis. Although symptomatic antibiotic treatment controls lung infections early in disease, lifelong bacterial residence typically ensues. Processes that control the establishment of persistent bacteria in the CF lung, and the contribution of noninfectious components to disease pathogenesis, are poorly understood.To evaluate whether continuous antibiotic therapy protects the CF lung from disease using a ferret model that rapidly acquires lethal bacterial lung infections in the absence of antibiotics.CFTR (cystic fibrosis transmembrane conductance regulator)-knockout ferrets were treated with three antibiotics from birth to several years of age and lung disease was followed by quantitative computed tomography, BAL, and histopathology. Lung disease was compared with CFTR-knockout ferrets treated symptomatically with antibiotics.Bronchiectasis was quantified from computed tomography images. BAL was evaluated for cellular differential and features of inflammatory cellular activation, bacteria, fungi, and quantitative proteomics. Semiquantitative histopathology was compared across experimental groups. We demonstrate that lifelong antibiotics can protect the CF ferret lung from infections for several years. Surprisingly, CF animals still developed hallmarks of structural bronchiectasis, neutrophil-mediated inflammation, and mucus accumulation, despite the lack of infection. Quantitative proteomics of BAL from CF and non-CF pairs demonstrated a mucoinflammatory signature in the CF lung dominated by Muc5B and neutrophil chemoattractants and products.These findings implicate mucoinflammatory processes in the CF lung as pathogenic in the absence of clinically apparent bacterial and fungal infections.

RATIONALE: Cleaning tasks may imply exposure to chemical agents with potential harmful effects to the respiratory system, and increased risk of asthma and respiratory symptoms among professional cleaners and in persons cleaning at home has been reported. Long-term consequences of cleaning agents on respiratory health are, however, not well described.OBJECTIVES: This study aimed to investigate long-term effects of occupational cleaning and cleaning at home on lung function decline and airway obstruction.METHODS: The European Community Respiratory Health Survey (ECRHS) investigated a multicenter population-based cohort at three time points over 20 years. A total of 6,235 participants with at least one lung function measurement from 22 study centers, who in ECRHS II responded to questionnaire modules concerning cleaning activities between ECRHS I and ECRHS II, were included. The data were analyzed with mixed linear models adjusting for potential confounders.MEASUREMENTS AND MAIN RESULTS: As compared with women not engaged in cleaning (ΔFEV1 = -18.5 ml/yr), FEV1 declined more rapidly in women responsible for cleaning at home (-22.1; P = 0.01) and occupational cleaners (-22.4; P = 0.03). The same was found for decline in FVC (ΔFVC = -8.8 ml/yr; -13.1, P = 0.02; and -15.9, P = 0.002; respectively). Both cleaning sprays and other cleaning agents were associated with accelerated FEV1 decline (-22.0, P = 0.04; and -22.9, P = 0.004; respectively). Cleaning was not significantly associated with lung function decline in men or with FEV1/FVC decline or airway obstruction.CONCLUSIONS: Women cleaning at home or working as occupational cleaners had accelerated decline in lung function, suggesting that exposures related to cleaning activities may constitute a risk to long-term respiratory health.

Studies of excised lungs show that significant airway attrition in the "quiet" zone occurs early in chronic obstructive pulmonary disease (COPD).To determine if the total number of airways quantified in vivo using computed tomography (CT) reflects early airway-related disease changes and is associated with lung function decline independent of emphysema in COPD.Participants in the multicenter, population-based, longitudinal CanCOLD (Canadian Chronic Obstructive Lung Disease) study underwent inspiratory/expiratory CT at visit 1; spirometry was performed at four visits over 6 years. Emphysema was quantified as the CT inspiratory low-attenuation areas below -950 Hounsfield units. CT total airway count (TAC) was measured as well as airway inner diameter and wall area using anatomically equivalent airways.Participants included never-smokers (n = 286), smokers with normal spirometry at risk for COPD (n = 298), Global Initiative for Chronic Obstructive Lung Disease (GOLD) I COPD (n = 361), and GOLD II COPD (n = 239). TAC was significantly reduced by 19% in both GOLD I and GOLD II compared with never-smokers (P 0.0001) and by 17% in both GOLD I and GOLD II compared with at-risk participants (P 0.0001) after adjusting for low-attenuation areas below -950 Hounsfield units. Further analysis revealed parent airways with missing daughter branches had reduced inner diameters (P 0.0001) and thinner walls (P 0.0001) compared with those without missing daughter branches. Among all CT measures, TAC had the greatest influence on FEVTAC may reflect the airway-related disease changes that accumulate in the "quiet" zone in early/mild COPD, indicating that TAC acquired with commercially available software across various CT platforms may be a biomarker to predict accelerated COPD progression.

Inhaled corticosteroids have been shown to decrease exacerbations in patients with moderate to severe chronic obstructive pulmonary disease (COPD). Their effects in patients with milder airflow obstruction remain unclear.This was an analysis of exacerbations in the SUMMIT (Study to Understand Mortality and Morbidity) study.In a double-blind, randomized controlled trial, once-daily inhaled placebo, fluticasone furoate (FF; 100 μg), vilanterol (VI; 25 μg), or the combination of FF/VI was administered. The primary outcome was all-cause mortality. Exacerbations of COPD were an additional predefined endpoint. A total of 1,368 centers in 43 countries and 16,485 patients with moderate COPD and heightened cardiovascular risk were included in the study.Compared with placebo, FF/VI reduced the rate of moderate and/or severe exacerbations by 29% (95% confidence interval [CI], 22-35; P 0.001) and the rate of hospitalized exacerbations by 27% (95% CI, 13-39; P 0.001). These relative effects were similar regardless of whether subjects had a history of exacerbation in the year before the study or an FEVPatients with moderate chronic airflow obstruction experienced a reduction in exacerbations with FF/VI compared with placebo, irrespective of a history of exacerbations or baseline FEV

Oral appliances (OAs) are commonly used as an alternative treatment to continuous positive airway pressure for patients with obstructive sleep apnea (OSA). However, OAs have variable success at reducing the apnea-hypopnea index (AHI), and predicting responders is challenging. Understanding this variability may lie with the recognition that OSA is a multifactorial disorder and that OAs may affect more than just upper-airway anatomy/collapsibility.The objectives of this study were to determine how OA alters AHI and four phenotypic traits (upper-airway anatomy/collapsibility and muscle function, loop gain, and arousal threshold), and baseline predictors of which patients gain the greatest benefit from therapy.In a randomized crossover study, 14 patients with OSA attended two sleep studies with and without their OA. Under each condition, AHI and the phenotypic traits were assessed. Multiple linear regression was used to determine independent predictors of the reduction in AHI.OA therapy reduced the AHI (30 ± 5 vs. 11 ± 2 events/h; P 0.05), which was driven by improvements in upper-airway anatomy/collapsibility under passive (1.9 ± 0.7 vs. 4.7 ± 0.6 L/min; P 0.005) and active conditions (2.4 ± 0.9 vs. 6.2 ± 0.4 L/min; P 0.001). No changes were seen in muscle function, loop gain, or the arousal threshold. Using multivariate analysis, baseline passive upper-airway collapsibility and loop gain were independent predictors of the reduction in AHI (rOur findings suggest that OA therapy improves the upper-airway collapsibility under passive and active conditions. Importantly, a greater response to therapy occurred in those patients with a mild anatomic compromise and a lower loop gain.

Lower FEV1 is associated with increased prevalence of atherosclerosis; however, causal mechanisms remain elusive.To determine if systemic endothelial dysfunction mediates the association between reduced FEV1 and increased atherosclerosis.Brachial artery endothelial function, pulmonary function, coronary artery calcium, and carotid plaque were assessed in 231 Pittsburgh SCCOR (Specialized Centers for Clinically Oriented Research) study participants; peripheral arterial endothelial function, pulmonary function, and coronary artery calcium were assessed in 328 HeartSCORE (Heart Strategies Concentrating on Risk Evaluation) study participants.Lower FEV1 was independently associated with increased atherosclerosis in both cohorts (per 25% lower % predicted FEV1: odds ratio [OR], 1.76; 95% confidence interval [CI], 1.30-2.40; P 0.001 for carotid plaque in SCCOR participants) (per 25% lower % predicted FEV1: OR, 1.35; 95% CI, 1.02-1.77; P = 0.03 for coronary artery calcium in HeartSCORE participants). Similarly, reduced endothelial function was independently associated with increased atherosclerosis in both cohorts (per SD lower endothelial function: OR, 1.30; 95% CI, 1.01-1.67; P = 0.04 for carotid plaque in SCCOR participants) (per SD lower endothelial function: OR, 1.38; 95% CI, 1.09-1.76; P = 0.008 and OR, 1.41; 95% CI, 1.07-1.86; P = 0.01 for coronary artery calcium in SCCOR and HeartSCORE participants, respectively). However, there was no association between endothelial dysfunction and FEV1, FEV1/FVC, low-attenuation area/visual emphysema, and diffusing capacity in SCCOR participants, and between endothelial dysfunction and FEV1 or FEV1/FVC in HeartSCORE participants (all P 0.05). Adjusting the association between FEV1 and atherosclerosis for endothelial dysfunction had no impact.Endothelial dysfunction does not mediate the association between airflow limitation and atherosclerosis. Instead, airflow limitation and endothelial dysfunction seem to be unrelated and mutually independent predictors of atherosclerosis.

RATIONALE: After repeated cycles of lung infection and inflammation, patients with cystic fibrosis (CF) evolve to respiratory insufficiency. Although histology and imaging have provided descriptive information, a thorough morphometric analysis of end-stage CF lung disease is lacking. OBJECTIVES: To quantify the involvement of small and large airways in end-stage CF. METHODS: Multidetector computed tomography (MDCT) and micro-CT were applied to 11 air-inflated CF explanted lungs and 7 control lungs to measure, count, and describe the airway and parenchymal abnormalities in end-stage CF lungs. Selected abnormalities were further investigated with thin section histology. MEASUREMENTS AND MAIN RESULTS: On MDCT, CF explanted lungs showed an increased median (interquartile range) number (631 [511-710] vs. 344 [277-349]; P = 0.003) and size of visible airways (cumulative airway diameter 217 cm [209-250] vs. 91 cm [80-105]; P < 0.001) compared with controls. Airway obstruction was seen, starting from generation 6 and increasing to 40 to 50% of airways from generation 9 onward. Micro-CT showed that the total number of terminal bronchioles was decreased (2.9/ml [2.6-4.4] vs. 5.3/ml [4.8-5.7]; P < 0.001); 49% were obstructed, and the cross-sectional area of the open terminal bronchioles was reduced (0.093 mm(2) [0.084-0.123] vs. 0.179 mm(2) [0.140-0.196]; P < 0.001). On micro-CT, 41% of the obstructed airways reopened more distally. This remodeling was confirmed on histological analysis. Parenchymal changes were also seen, mostly in a patchy and peribronchiolar distribution. CONCLUSIONS: Extensive changes of dilatation and obstruction in nearly all airway generations were observed in end-stage CF lung disease. ispartof: AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE vol:193 issue:5 pages:516-526 ispartof: location:United States status: published

RationaleIn aging populations, the commonly used Global Initiative for Chronic Obstructive Lung Disease (GOLD) may misclassify normal spirometry as respiratory impairment (airflow obstruction and restrictive pattern), including the presumption of respiratory disease (chronic obstructive pulmonary disease [COPD]).ObjectivesTo evaluate the phenotype of normal spirometry as defined by a new approach from the Global Lung Initiative (GLI), overall and across GOLD spirometric categories.MethodsUsing data from COPDGene (n = 10,131; ages 45-81; smoking history, ≥10 pack-years), we evaluated spirometry and multiple phenotypes, including dyspnea severity (Modified Medical Research Council grade 0-4), health-related quality of life (St. George's Respiratory Questionnaire total score), 6-minute-walk distance, bronchodilator reversibility (FEV1 % change), computed tomography-measured percentage of lung with emphysema (% emphysema) and gas trapping (% gas trapping), and small airway dimensions (square root of the wall area for a standardized airway with an internal perimeter of 10 mm).Measurements and main resultsAmong 5,100 participants with GLI-defined normal spirometry, GOLD identified respiratory impairment in 1,146 (22.5%), including a restrictive pattern in 464 (9.1%), mild COPD in 380 (7.5%), moderate COPD in 302 (5.9%), and severe COPD in none. Overall, the phenotype of GLI-defined normal spirometry included normal adjusted mean values for dyspnea grade (0.8), St. George's Respiratory Questionnaire (15.9), 6-minute-walk distance (1,424 ft [434 m]), bronchodilator reversibility (2.7%), % emphysema (0.9%), % gas trapping (10.7%), and square root of the wall area for a standardized airway with an internal perimeter of 10 mm (3.65 mm); corresponding 95% confidence intervals were similarly normal. These phenotypes remained normal for GLI-defined normal spirometry across GOLD spirometric categories.ConclusionsGLI-defined normal spirometry, even when classified as respiratory impairment by GOLD, included adjusted mean values in the normal range for multiple phenotypes. These results suggest that among adults with GLI-defined normal spirometry, GOLD may misclassify normal phenotypes as having respiratory impairment.