Oxidative Stress in Cystic Fibrosis: Dietary and Metabolic Factors

Abstract

Objective: To examine oxidative stress in CF by measuring 8-iso-PGF2α and antioxidant defenses, in relation to dietary intake, immune function and clinical status.Methods: We measured total plasma concentrations of 8-iso-PGF2α and dietary antioxidants (vitamin E, vitamin C, β-carotene), erythrocyte antioxidant enzyme activities (glutathione peroxidase and superoxide dismutase), lung function and dietary intake in 21 CF subjects and 21 healthy age- and gender-matched controls.Results: Total plasma 8-iso-PGF2α concentration (median [quartile 1–quartile 3]) was significantly higher in CF subjects compared to controls (214 pg/mL (155–331) vs. 135 pg/mL (101–168), p=0.001). Neutrophil, monocyte and total white cell counts were elevated in the CF group and these correlated with 8-iso-PGF2α concentration. Despite similar dietary intake, lower plasma antioxidant concentrations were observed in the CF group (vitamin E, p < 0.001, vitamin C, p=0.004, β-carotene, p=0.001). 8-iso-PGF2α correlated negatively with plasma vitamin E, C and β-carotene concentrations.Conclusion: Oxidative stress is increased in CF patients, despite normal dietary antioxidant intake. The immune response appears to be a key factor causing oxidative stress. Antioxidant intervention aimed at reducing oxidative stress in CF needs to be assessed.