Oxidative Stress in Cystic Fibrosis: Dietary and Metabolic Factors
Lisa G. Wood, BSc (Hons), Dominic A. Fitzgerald, MBBS, PhD, Peter G. Gibson, MBBS, David M. Cooper, MBBS, Clare E. Collins, PhD, and Manohar L. Garg, PhD
Discipline of Nutrition and Dietetics, University of Newcastle (L.G.W., M.L.G.), Department of Paediatrics (D.A.F., D.M.C.), Airway Research Centre, Department of Respiratory Medicine (P.G.G.), Department of Dietetics (C.E.C.), John Hunter Children’s Hospital, Newcastle, Department of Respiratory Medicine, New Children’s Hospital, Sydney (D.A.F.), New South Wales, AUSTRALIA [ndmg@medicine.newcastle.edu.au]
Objective: To examine oxidative stress in CF by measuring 8-iso-PGF2 and antioxidant defenses, in relation to dietary intake, immune function and clinical status.
Methods: We measured total plasma concentrations of 8-iso-PGF2 and dietary antioxidants (vitamin E, C, -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-PGF2 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-PGF2 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, -carotene, p = 0.001). 8-iso-PGF2 correlated negatively with plasma vitamin E, C and -carotene concentrations. 8-iso-PGF2 concentration correlated with duration since last oral antibiotic treatment in the CF group.
Conclusion: Oxidative stress is increased and related to clinical status 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.