title: Downregulation of peroxisome proliferator-activated receptors (PPARs) in nasal polyposis.
abstract: BACKGROUND
  Peroxisome proliferator-activated receptor (PPAR) alpha, betadelta and gamma are nuclear receptors activated by fatty acid metabolites. An anti-inflammatory role for these receptors in airway inflammation has been suggested.
  
  
  METHODS
  Nasal biopsies were obtained from 10 healthy volunteers and 10 patients with symptomatic allergic rhinitis. Nasal polyps were obtained from 22 patients, before and after 4 weeks of local steroid treatment (fluticasone). Real-time RT-PCR was used for mRNA quantification and immunohistochemistry for protein localization and quantification.
  
  
  RESULTS
  mRNA expression of PPARalpha, PPARbetadelta, PPARgamma was found in all specimens. No differences in the expression of PPARs were obtained in nasal biopsies from patients with allergic rhinitis and healthy volunteers. Nasal polyps exhibited lower levels of PPARalpha and PPARgamma than normal nasal mucosa and these levels were, for PPARgamma, further reduced following steroid treatment. PPARgamma immunoreactivity was detected in the epithelium, but also found in smooth muscle of blood vessels, glandular acini and inflammatory cells. Quantitative evaluation of the epithelial immunostaining revealed no differences between nasal biopsies from patients with allergic rhinitis and healthy volunteers. In polyps, the PPARgamma immunoreactivity was lower than in nasal mucosa and further decreased after steroid treatment.
  
  
  CONCLUSIONS
  The down-regulation of PPARgamma, in nasal polyposis but not in turbinates during symptomatic seasonal rhinitis, suggests that PPARgamma might be of importance in long standing inflammations.
authors.affiliation: Department of Otorhinolaryngology, Lund University, Malmö University Hospital, Malmö, Sweden. Lars-Olaf.Cardell@med.lu.se
authors.forename: Lars-Olaf
authors.initials: LO
authors.lastname: Cardell
authors.forename: Magnus
authors.initials: M
authors.lastname: Hägge
authors.forename: Rolf
authors.initials: R
authors.lastname: Uddman
authors.forename: Mikael
authors.initials: M
authors.lastname: Adner
mesh_terms: D000328:Adult; D000368:Aged; D015536:Down-Regulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009297:Nasal Mucosa / Q000378:metabolism*; D009298:Nasal Polyps / Q000209:etiology / Q000378:metabolism* / Q000473:pathology*; D047492:Peroxisome Proliferator-Activated Receptors / Q000378:metabolism*; D006255:Rhinitis, Allergic, Seasonal / Q000150:complications / Q000378:metabolism* / Q000473:pathology*
chemical_list: D047492:Peroxisome Proliferator-Activated Receptors