Up-regulation of peroxisome proliferator-activated receptor γ in perennial allergic rhinitis

Objectives: To investigate the expression of peroxisome proliferator-activated receptor γ (PPAR-γ) messenger RNA and protein and to localize the PPAR-γ protein in the nasal mucosa of patients with allergic rhinitis and control subjects. Design: Prospective study. Setting: Tertiary academic institution. Patients: Twenty patients with perennial allergic rhinitis and 20 matched nonallergic patients. Interventions: Inferior turbinate mucosa samples were obtained from 20 patients with perennial allergic rhinitis and 20 matched nonallegic patients. Peroxisome proliferator-activated receptor γ messenger RNA was extracted from the inferior turbinate mucosae, and then reverse transcription-polymerase chain reaction was performed. Western blot testing was used to analyze differences in PPAR-γ protein expression levels between patients with allergic rhinitis and normal controls, and the PPAR-γ protein was localized immunohistochemically. Results: The expression levels of PPAR-γ messenger RNA and protein in the nasal mucosa was significantly increased in patients with perennial allergic rhinitis compared with controls. Peroxisome proliferator-activated receptor γ protein was expressed in the epithelium, infiltrating inflammatory cells, and submucosal glands. Conclusions: Peroxisome proliferator-activated receptor γ is expressed in the human nasal mucosa and is up-regulated in perennial allergic rhinitis. These results suggest a possible contribution for PPAR-γ in chronic inflammation of the nasal mucosa in perennial allergic rhinitis.