title: Effects of obesity and bariatric surgery on airway hyperresponsiveness, asthma control, and inflammation.
abstract: BACKGROUND
  Asthma in obese subjects is poorly understood, and these patients are often refractory to standard therapy.
  
  
  OBJECTIVE
  We sought to gain insights into the pathogenesis and treatment of asthma in obese subjects by determining how obesity and bariatric surgery affect asthma control, airway hyperresponsiveness (AHR), and markers of asthmatic inflammation.
  
  
  METHODS
  We performed a prospective study of (1) asthmatic and nonasthmatic patients undergoing bariatric surgery compared at baseline and (2) asthmatic patients followed for 12 months after bariatric surgery.
  
  
  RESULTS
  We studied 23 asthmatic and 21 nonasthmatic patients undergoing bariatric surgery. At baseline, asthmatic patients had lower FEV(1) and forced vital capacity and lower numbers of lymphocytes in bronchoalveolar lavage fluid. After surgery, asthmatic participants experienced significant improvements in asthma control (asthma control score, 1.55 to 0.74; P < .0001) and asthma quality of life (4.87 to 5.87, P < .0001). Airways responsiveness to methacholine improved significantly (methacholine PC(20), 3.9 to 7.28, P = .03). There was a statistically significant interaction between IgE status and change in airways responsiveness (P for interaction = .01). The proportion of lymphocytes in bronchoalveolar lavage fluid and the production of cytokines from activated peripheral blood CD4(+) T cells increased significantly.
  
  
  CONCLUSIONS
  Bariatric surgery improves AHR in obese asthmatic patients with normal serum IgE levels. Weight loss has dichotomous effects on airway physiology and T-cell function typically involved in the pathogenesis of asthma, suggesting that obesity produces a unique phenotype of asthma that will require a distinct therapeutic approach.
authors.affiliation: Department of Medicine, University of Vermont College of Medicine, Burlington, VT 05405, USA. Anne.dixon@vtmednet.org
authors.forename: Anne E
authors.initials: AE
authors.lastname: Dixon
authors.forename: Richard E
authors.initials: RE
authors.lastname: Pratley
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Forgione
authors.forename: David A
authors.initials: DA
authors.lastname: Kaminsky
authors.forename: Laurie A
authors.initials: LA
authors.lastname: Whittaker-Leclair
authors.forename: Laurianne A
authors.initials: LA
authors.lastname: Griffes
authors.forename: Jayanthi
authors.initials: J
authors.lastname: Garudathri
authors.forename: Danielle
authors.initials: D
authors.lastname: Raymond
authors.forename: Mathew E
authors.initials: ME
authors.lastname: Poynter
authors.forename: Janice Y
authors.initials: JY
authors.lastname: Bunn
authors.forename: Charles G
authors.initials: CG
authors.lastname: Irvin
mesh_terms: D000328:Adult; D001249:Asthma / Q000150:complications* / Q000276:immunology / Q000503:physiopathology / Q000517:prevention & control*; D050110:Bariatric Surgery / Q000379:methods*; D016535:Bronchial Hyperreactivity; D001992:Bronchoalveolar Lavage Fluid; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007249:Inflammation; D008297:Male; D016210:Methacholine Chloride / Q000494:pharmacology; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000601:surgery*; D011446:Prospective Studies; D012129:Respiratory Function Tests; D016896:Treatment Outcome; D015431:Weight Loss
chemical_list: D016210:Methacholine Chloride