Oxidative stress in cystic fibrosis: dietary and metabolic factors

Abstract

Objective: To examine oxidative stress in CF by measuring 8-iso-PGF2alpha and antioxidant defenses, in relation to dietary intake, immune function and clinical status.

Methods: We measured total plasma concentrations of 8-iso-PGF2alpha and dietary antioxidants (vitamin E, vitamin C, beta-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-PGF2alpha 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-PGF2alpha 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, beta-carotene, p = 0.001). 8-iso-PGF2alpha correlated negatively with plasma vitamin E, C and beta-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.