Peroxisome Proliferator-Activated Receptor alpha (PPAR alpha) down-regulation in cystic fibrosis lymphocytes

Background: PPARs exhibit anti-inflammatory capacities and are potential modulators of the inflammatory response. We hypothesized that their expression and/or function may be altered in cystic fibrosis (CF), a disorder characterized by an excessive host inflammatory response. Methods: PPARα, β and γ mRNA levels were measured in peripheral blood cells of CF patients and healthy subjects via RT-PCR. PPARα protein expression and subcellular localization was determined via western blot and immunofluorescence, respectively. The activity of PPARα was analyzed by gel shift assay. Results: In lymphocytes, the expression of PPARα mRNA, but not of PPARβ, was reduced (-37%; p < 0.002) in CF patients compared with healthy persons and was therefore further analyzed. A similar reduction of PPARα was observed at protein level (-26%; p < 0.05). The transcription factor was mainly expressed in the cytosol of lymphocytes, with low expression in the nucleus. Moreover, DNA binding activity of the transcription factor was 36% less in lymphocytes of patients (p < 0.01). For PPARα and PPARβ mRNA expression in monocytes and neutrophils, no significant differences were observed between CF patients and healthy persons. In all cells, PPARγ mRNA levels were below the detection limit. Conclusion: Lymphocytes are important regulators of the inflammatory response by releasing cytokines and antibodies. The diminished lymphocytic expression and activity of PPARα may therefore contribute to the inflammatory processes that are observed in CF

Azithromycin reduces spontaneous and induced inflammation in ΔF508 cystic fibrosis mice

BACKGROUND: Inflammation plays a critical role in lung disease development and progression in cystic fibrosis. Azithromycin is used for the treatment of cystic fibrosis lung disease, although its mechanisms of action are poorly understood. We tested the hypothesis that azithromycin modulates lung inflammation in cystic fibrosis mice. METHODS: We monitored cellular and molecular inflammatory markers in lungs of cystic fibrosis mutant mice homozygous for the ΔF508 mutation and their littermate controls, either in baseline conditions or after induction of acute inflammation by intratracheal instillation of lipopolysaccharide from Pseudomonas aeruginosa, which would be independent of interactions of bacteria with epithelial cells. The effect of azithromycin pretreatment (10 mg/kg/day) given by oral administration for 4 weeks was evaluated. RESULTS: In naive cystic fibrosis mice, a spontaneous lung inflammation was observed, characterized by macrophage and neutrophil infiltration, and increased intra-luminal content of the pro-inflammatory cytokine macrophage inflammatory protein-2. After induced inflammation, cystic fibrosis mice combined exaggerated cellular infiltration and lower anti-inflammatory interleukin-10 production. In cystic fibrosis mice, azithromycin attenuated cellular infiltration in both baseline and induced inflammatory condition, and inhibited cytokine (tumor necrosis factor-α and macrophage inflammatory protein-2) release in lipopolysaccharide-induced inflammation. CONCLUSION: Our findings further support the concept that inflammatory responses are upregulated in cystic fibrosis. Azithromycin reduces some lung inflammation outcome measures in cystic fibrosis mice. We postulate that some of the benefits of azithromycin treatment in cystic fibrosis patients are due to modulation of lung inflammation

Cytokines and inflammatory mediators do not indicate acute infection in cystic fibrosis

Various treatment regimens and difficulties with research design are encountered with cystic fibrosis (CF) because no standard diagnostic criteria exist for defining acute respiratory exacerbations. This study evaluated the role of serial monitoring of concentrations of selected cytokines and inflammatory mediators in serum and sputum as predictors of respiratory exacerbation, as useful outcome measures for CF, and to guide therapy. Interleukin-8 (IL-8), tumor necrosis factor alpha (TNF-α), neutrophil elastase-α-l-protease inhibitor complex (NE complex), protein, and α-1- protease inhibitor (α-1-PI) were measured in serum and sputum collected from CF patients during respiratory exacerbations and periods of well-being. Levels of NE complex, protein, and α-1-PI in sputum rose during respiratory exacerbations and fell after institution of antibiotic therapy (P = 0.078, 0.001, and 0.002, respectively). Mean (± standard error of the mean) levels of IL-8 and TNF-α were extremely high in sputum (13,780 ± 916 and 249.4 ± 23.5 ng/liter, respectively) but did not change significantly with clinical deterioration of the patient (P > 0.23). IL-8 and TNF-α were generally undetectable in serum, and therefore these measures were unhelpful. Drop in forced expiratory volume in 1 s was the only clinical or laboratory parameter that was close to being a determinant of respiratory exacerbation (P = 0.055). This study provides evidence of intense immunological activity occurring continually within the lungs of adult CF patients. Measurement of cytokines and inflammatory mediators in CF sputum is not helpful for identifying acute respiratory exacerbations