American journal of respiratory and critical care medicine
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Am. J. Respir. Crit. Care Med. · Feb 2020
Disease Progression Modeling in Chronic Obstructive Pulmonary Disease.
Rationale: The decades-long progression of chronic obstructive pulmonary disease (COPD) renders identifying different trajectories of disease progression challenging. Objectives: To identify subtypes of patients with COPD with distinct longitudinal progression patterns using a novel machine-learning tool called "Subtype and Stage Inference" (SuStaIn) and to evaluate the utility of SuStaIn for patient stratification in COPD. Methods: We applied SuStaIn to cross-sectional computed tomography imaging markers in 3,698 Global Initiative for Chronic Obstructive Lung Disease (GOLD) 1-4 patients and 3,479 controls from the COPDGene (COPD Genetic Epidemiology) study to identify subtypes of patients with COPD. ⋯ Individuals with early changes were 2.5 times more likely to meet COPD diagnostic criteria at follow-up. Conclusions: We demonstrate two distinct patterns of disease progression in COPD using SuStaIn, likely representing different endotypes. One third of healthy smokers have detectable imaging changes, suggesting a new biomarker of "early COPD."
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Am. J. Respir. Crit. Care Med. · Feb 2020
General and Organ Fat Assessed by Magnetic Resonance Imaging and Respiratory Outcomes in Childhood.
Rationale: Obesity has been implicated as a pathogenic factor in asthma, but the underlying role of general and organ fat is unclear. Objectives: We hypothesized that organ fat, rather than the total fat mass, increases the risk of asthma. Methods: In a population-based prospective cohort study among 5,421 children aged 10 years, we measured general fat including body mass index and fat mass index by dual-energy X-ray absorptiometry, and organ fat including subcutaneous fat index, visceral fat index, pericardial fat index, and liver fat fraction by magnetic resonance imaging. ⋯ Higher visceral fat index, independent of fat mass index, was associated with higher FVC (z-score difference [95% CI], 0.07 [0.03 to 0.10]), lower FEV1/FVC (z-score difference [95% CI], -0.05 [-0.09 to -0.01]), and higher risk of asthma (odds ratio, 1.20; 95% CI, 1.01 to 1.43 per SD score increase). No other organ fat measures were independently associated with lung function or asthma. Conclusions: The obesity-asthma link is driven mainly by visceral fat, independent of total fat mass; therefore, abdominal fat might contribute to asthma development.
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Am. J. Respir. Crit. Care Med. · Feb 2020
Nasal Pneumococcal Density Is Associated with Microaspiration and Heightened Human Alveolar Macrophage Responsiveness to Bacterial Pathogens.
Rationale: Pneumococcal pneumonia remains a global health problem. Colonization of the nasopharynx with Streptococcus pneumoniae (Spn), although a prerequisite of infection, is the main source of exposure and immunological boosting in children and adults. However, our knowledge of how nasal colonization impacts on the lung cells, especially on the predominant alveolar macrophage (AM) population, is limited. ⋯ Similarly, AM-heightened opsonophagocytic capacity was correlated with nasopharyngeal pneumococcal density (r = 0.61, P = 0.025). Conclusions: Our findings demonstrate that nasal colonization with pneumococcus and microaspiration prime AMs, leading to brisker responsiveness to both pneumococcus and unrelated bacterial pathogens. The relative abundance of AMs in the alveolar spaces, alongside their potential for nonspecific protection, render them an attractive target for novel vaccines.