Azithromycin fails to reduce increased expression of neutrophil-related cytokines in primary-cultured epithelial cells from cystic fibrosis mice.

Background: Beneficial effects of azithromycin in cystic fibrosis (CF) have been reported, however, its mechanism of action remains unclear. The present study aimed at investigating the effect of azithromycin on CF airway epithelial cells.
Methods: Primary cultures of purified tracheal epithelial cells from F508del and normal homozygous mice were established. Responses to lipopolysaccharide from Pseudomonas aeruginosa (LPS, 0.1 microg/ml) on mRNA expression of neutrophil-related chemokines, pro- and anti-inflammatory cytokines were investigated in the presence or the absence of azithromycin (1 microg/ml).
Results: CF airway epithelial cells showed upregulation of MIP-2 and KC responses to LPS, and azithromycin failed to downregulate these responses. In contrast, in CF cells, azithromycin increased KC and TNF-alpha expression under non-stimulated and LPS-stimulated conditions, respectively. In non-CF cells, the macrolide potentiated the LPS response on MIP-2 and on IL-10.
Conclusions: Airway epithelial cells contribute to the dysregulated immune processes in CF. Azithromycin rather stimulates cytokine expression in CF airway epithelial cells.