Flow‐Mediated Dilation is Attenuated in Young Patients with Cystic Fibrosis

Abstract

Cystic fibrosis (CF) is a fatal genetic disorder that affects the lungs as well as multiple biological systems. This study sought to determine if endothelial function, measured by the flow‐mediated dilation (FMD) test, was lower in patients with CF compared to controls. 15 patients with CF and 15 demographically matched controls participated in this study. Overnight fasting blood samples were taken and FMD and spirometry were performed. No differences in age, height, or BMI were observed between patients with CF and controls (all p>0.05). Although lung function was in the normal range, patients with CF had lower FEV1 when compared to healthy controls (92.8±15 vs. 104.5±11 % predicted). In addition, brachial artery FMD was lower in patients with CF compared to controls (5.0±2.7 vs. 7.6±3.1%; p=0.02) which was accompanied by a slightly higher plasma concentration of 8‐ isoprostane (16±2 vs. 12±1 ng/ml; p=0.20) and NOx (48±5 vs. 35±4 uM; p=0.06) and a lower total antioxidant capacity (1.29±0.11 vs. 1.42±0.08 mM; p=0.38) compared to controls. These data indicate that young patients with cystic fibrosis have impaired endothelial function that precedes the decline in pulmonary function. Systemic oxidative stress and inflammation may be a contributor; however, more subjects are needed to elucidate this mechanism.Supported in part by the American Heart Association (R.A.H) and Child Health Discovery Institute (R.A.H).