Alveolar Macrophages from Overweight/Obese Subjects with Asthma Demonstrate a Proinflammatory Phenotype

• Published in: American journal of respiratory and critical care medicine Vol. 186; no. 5; pp. 404 - 411
• Main Authors: LUGOGO, Njira L, HOLLINGSWORTH, John W, KRAFT, Monica, HOWELL, Druhan L, QUE, Loretta G, FRANCISCO, Dave, CHURCH, Tony D, POTTS-KANT, Erin N, INGRAM, Jennifer L, YING WANG, JUNG, Sin-Ho
• Format: Journal Article
• Language: English
• Published: New York, NY American Thoracic Society 01.09.2012
• Subjects: Adolescent; Adult; Aged; Analysis of Variance; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Asthma; Asthma - etiology; Asthma - immunology; Asthma - metabolism; Biological and medical sciences; Biomarkers - metabolism; Body fat; Body mass index; Bronchoalveolar Lavage Fluid - chemistry; Bronchoalveolar Lavage Fluid - immunology; Bronchoalveolar Lavage Fluid - microbiology; Bronchoscopy; Case-Control Studies; Cells, Cultured; Chronic obstructive pulmonary disease, asthma; Cytokines; Cytokines - metabolism; Disease; Enzyme-Linked Immunosorbent Assay; Female; Genotype & phenotype; Granulocytes; Humans; Inflammation; Intensive care medicine; Lavage; Leptin - metabolism; Linear Models; Lipopolysaccharides - immunology; Macrophages, Alveolar - metabolism; Male; Medical sciences; Middle Aged; Obesity; Obesity - complications; Obesity - immunology; Obesity - metabolism; Overweight; Overweight - complications; Overweight - immunology; Overweight - metabolism; Pathogenesis; Phenotype; Pneumology; Proteins; Steroids; Tumor necrosis factor-TNF; Young Adult; Human; Obesity; Lung disease; Intensive care; Respiratory disease; Cytokine; Nutrition disorder; Immunity; Asthma; Overweight; environmental lung disease; Phenotype; innate immunity; Leptin; tumor necrosis factor-α; Lipopolysaccharide; Bronchus disease; Tumor necrosis factor β; Obstructive pulmonary disease; Nutritional status; Tumor necrosis factor α; Resuscitation; Macrophage
• ISSN: 1073-449X; 1535-4970
• DOI: 10.1164/rccm.201109-1671OC

Obesity is associated with increased prevalence and severity of asthma. Adipose tissue macrophages can contribute to the systemic proinflammatory state associated with obesity. However, it remains unknown whether alveolar macrophages have a unique phenotype in overweight/obese patients with asthma. We hypothesized that leptin levels would be increased in the bronchoalveolar lavage fluid from overweight/obese subjects and, furthermore, that leptin would alter the response of alveolar macrophages to bacterial LPS. Forty-two subjects with asthma and 46 healthy control subjects underwent research bronchoscopy. Bronchoalveolar lavage fluid from 66 was analyzed for the level of cellular inflammation, cytokines, and soluble leptin. Cultured primary macrophages from 22 subjects were exposed to LPS, leptin, or leptin plus LPS. Cytokines were measured in the supernatants. Leptin levels were increased in overweight/obese subjects, regardless of asthma status (P = 0.013), but were significantly higher in overweight/obese subjects with asthma. Observed levels of tumor necrosis factor-α were highest in overweight/obese subjects with asthma. Ex vivo studies of primary alveolar macrophages indicated that the response to LPS was most robust in alveolar macrophages from overweight/obese subjects with asthma and that preexposure to high-dose leptin enhanced the proinflammatory response. Leptin alone was sufficient to induce production of proinflammatory cytokines from macrophages derived from overweight/obese subjects with asthma. Ex vivo studies indicate that alveolar macrophages derived from overweight/obese subjects with asthma are uniquely sensitive to leptin. This macrophage phenotype, in the context of higher levels of soluble leptin, may contribute to the pathogenesis of airway disease associated with obesity.