title: Imbalance of endogenous prostanoids in moderate-to-severe asthma.
abstract: BACKGROUND
  Inhalation studies suggested "protective" roles of exogenous prostaglandin E2, but the clinical relevance of endogenous prostanoids in asthma is poorly known. The objective of this study is to measure sputum levels of prostanoids in asthmatic patients to correlate with clinical indices.
  
  
  METHODS
  Mild (n = 41) or moderate-to-severe (19) asthmatics and 27 normal controls were examined for pulmonary function (FEV1and mid-forced expiratory flow), sputum cell differentials, and sputum levels of prostaglandins D2, E2, F2α, and thromboxane B2measured by sandwich enzyme immunoassay.
  
  
  RESULTS
  Each prostanoid level did not differ among the three groups. Sputum number of bronchial epithelial cells was greater in moderate-to-severe asthmatics than in the other two groups, suggesting epithelial desquamation. Levels of prostaglandin F2α, D2, and thromboxane B2positively correlated with the severity of airflow obstruction in the 60 asthmatic patients, whereas prostaglandin E2levels were unrelated to pulmonary function. The ratio of combined "contractile" prostanoids (prostaglandin D2/prostaglandin F2α/thromboxane B2) to prostaglandin E2was 2.5-fold greater in moderate-to-severe asthmatics than in controls (p = 0.001) or in mild asthmatics (p = 0.0002) but did not differ between the latter two groups. In the two asthmatic groups combined, this ratio positively correlated with the sputum number of epithelial cells. The combined "contractile" prostanoids levels positively correlated with prostaglandin E2levels in controls and in mild asthmatics but not in moderate-to-severe asthmatics.
  
  
  CONCLUSIONS
  An imbalance in production, breakdown, or both between prostaglandin E2and other prostanoids possibly due to epithelial damage may be involved in the pathogenesis of moderate-to-severe asthma.
authors.affiliation: Department of Respiratory Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Takemura
authors.affiliation: Department of Respiratory Medicine, Kyoto University, Kyoto, Japan; Department of Respiratory Medicine, Allergy and Clinical Immunology, Nagoya City University, School of Medical Sciences, Nagoya, Japan. Electronic address: a.niimi@med.nagoya-cu.ac.jp.
authors.forename: Akio
authors.initials: A
authors.lastname: Niimi
authors.affiliation: Department of Respiratory Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Hisako
authors.initials: H
authors.lastname: Matsumoto
authors.affiliation: Department of Respiratory Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Ueda
authors.affiliation: Department of Respiratory Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Yamaguchi
authors.affiliation: Department of Respiratory Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Matsuoka
authors.affiliation: Department of Respiratory Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Makiko
authors.initials: M
authors.lastname: Jinnai
authors.affiliation: Thoracic Medicine, National Heart & Lung Institute, Imperial College, London, UK.
authors.forename: Kian Fan
authors.initials: KF
authors.lastname: Chung
authors.affiliation: Department of Respiratory Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Michiaki
authors.initials: M
authors.lastname: Mishima
mesh_terms: D000328:Adult; D001249:Asthma / Q000188:drug therapy* / Q000378:metabolism*; D005260:Female; D005540:Forced Expiratory Flow Rates; D006801:Humans; D008297:Male; D008875:Middle Aged; D011453:Prostaglandins / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D012720:Severity of Illness Index; D013183:Sputum
chemical_list: D011453:Prostaglandins
keywords: Asthma; Epithelial damage; Induced sputum; Prostaglandin; Thromboxane