title: Peroxisome proliferator-activated receptor-γ is expressed in eosinophils in nasal polyps.
abstract: BACKGROUND
  Peroxisome proliferator-activated receptor-γ (PPARγ) is a member of the nuclear receptors, which regulate fatty acid metabolites. One of the natural ligands for PPARγ is 15-deoxy-Δ(12,14)-prostaglandin J(2) (15d-PGJ(2)), a major metabolite of prostaglandin D(2) (PGD(2)). Recently, PPARγ has been shown to play an important role in anti-inflammatory reactions, including within-airway allergic diseases, in a mouse model. Our aim was to clarify the expression and localization of PPARγ and PGD(2) synthase, which produces ligands of PPARγ, in nasal polyps by immunohistochemical analysis.
  
  
  METHODS
  Nasal polyps of chronic rhinosinusitis patients (6 asthmatic patients and 6 nonasthmatic patients) were obtained during surgery. May-Grünwald-Giemsa staining was performed to evaluate the eosinophil infiltration of the polyps. To identify the cells expressing PPARγ protein and PGD(2) synthase, double immunostaining was performed using anti-PPARγ antibody, monoclonal antileukocyte antibodies, and PGD(2) synthase antibody.
  
  
  RESULTS
  The number of eosinophils and the number of PPARγ-positive cells in the nasal polyps of the asthmatic patients were significantly higher than those in the nonasthmatic patients. PPARγ was expressed on eosinophils and T cells of the infiltrating cells in the nasal polyps. PGD(2) synthase was also expressed on PPARγ-positive cells.
  
  
  CONCLUSIONS
  PPARγ is involved in nasal polyposis pathogenesis, acting on eosinophils and T cells.
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Akita University Graduate School of Medicine, Akita, Japan. asaka@med.akita-u.ac.jp
authors.forename: Chikara
authors.initials: C
authors.lastname: Asaka
authors.forename: Kohei
authors.initials: K
authors.lastname: Honda
authors.forename: Eiko
authors.initials: E
authors.lastname: Ito
authors.forename: Naoko
authors.initials: N
authors.lastname: Fukui
authors.forename: Junichi
authors.initials: J
authors.lastname: Chihara
authors.forename: Kazuo
authors.initials: K
authors.lastname: Ishikawa
mesh_terms: D001249:Asthma / Q000150:complications / Q000473:pathology; D002452:Cell Count; D004804:Eosinophils / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000378:metabolism; D054834:Lipocalins / Q000378:metabolism; D009298:Nasal Polyps / Q000209:etiology / Q000378:metabolism / Q000473:pathology*; D047495:PPAR gamma / Q000378:metabolism*; D012220:Rhinitis / Q000150:complications / Q000473:pathology; D012852:Sinusitis / Q000150:complications / Q000473:pathology; D013601:T-Lymphocytes / Q000378:metabolism
chemical_list: D054834:Lipocalins; D047495:PPAR gamma; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase