NO synthesis in the airway epithelium is regulated by nitric oxide synthase 2 (NOS2). NOS2 expression is negatively regulated by the Rho GTPases, which are over-expressed in CF and may also play a role in the inflammatory dysregulation characteristic of the lung disease. Inhibition of the Rho GTPases with 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoAR) inhibitors, such as simvastatin (Zocor®), increases NOS2 protein expression in CF airway epithelial cells. The statins have also been shown to have potent systemic anti-inflammatory effects, many of which may be pertinent to CF. We propose to test the hypothesis that HMG-CoAR inhibitors, such as simvastatin, have the potential to correct abnormalities in NO production and decrease inflammation in the airways of patients with CF. The following specific aims will be pursued in this application: 1) To determine the effect of simvastatin treatment on exhaled nitric oxide (eNO) concentrations in subjects with CF; 2) To determine the effect of simvastatin treatment on inflammation and NOS2 production in the airway of subjects with CF, as determined by quantitative RT-PCR for IL-6, IL-8, and NOS2 mRNA in nasal epithelial cells; 3) To determine if quantitative RT-PCR measurements on nasal epithelial cells might be used as a surrogate marker of lower airway inflammation by comparing the measures obtained from nasal epithelial scrapes with inflammatory measurements obtained from induced sputum.