Effect of Simvastatin on CF Airway Inflammation

Individuals with cystic fibrosis (CF) have persistent infection in the airways, which the body attempts to fight by recruiting immune cells (neutrophils) to the lung. The immune system and neutrophils are unable to completely kill the bacteria, and the response to the infection leads to inflammation (swelling) of the airways and lung damage. Nitric oxide (NO) has anti-bacterial and anti-inflammatory properties in the lung. NO production is decreased in CF patients, and may contribute to the persistent infection and inflammation. Increasing the production of NO in the airways of CF patients may help decrease this inflammation and infection. Rho GTPases are molecules in the cells that line the airways that decrease the protein that makes nitric oxide (NOS). Rho proteins also increase inflammation in these cells. Rho proteins are increased in CF cells, and may partially explain the low NO and high inflammation seen in CF. Blocking the Rho protein in CF cells increases NOS, which can then produce more NO. The Rho protein can be inhibited with a drug, simvastatin (Zocor®). Simvastatin is used by millions of people to lower their cholesterol, is very safe, has few side-effects and is approved for use in children greater than 10 years of age. We propose that treating CF patients with simvastatin will increase NO produced (exhaled NO), and may decrease airway inflammation. If simvastatin has these expected effects in CF, it would be another drug that has potential to become a new therapy to fight the debilitating lung damage of the disease.