Increased plasma fatty acid concentrations after respiratory exacerbations are associated with elevated oxidative stress in cystic fibrosis patients

Abstract

Background: Oxidative stress and depleted antioxidant defenses occur in stable cystic fibrosis patients. During acute infection, the balance between oxidants and antioxidants may be further disturbed. Objective: We examined the oxidative stress during acute infection in cystic fibrosis patients by measuring 8-iso-prostaglandin F2α (8-iso-PGF2α) and antioxidant defenses in relation to dietary intake, fatty acid status, immune function, and clinical status. Design: Plasma concentrations of total 8-iso-PGF2α, vitamins E and C, β-carotene, zinc, selenium, and copper; plasma fatty acid compositions; erythrocyte glutathione concentrations; glutathione peroxidase and superoxide dismutase activity; sputum glutathione and 8-iso-PGF2α concentrations; lung function; clinical symptoms; and dietary intake were measured in 15 cystic fibrosis patients before and after 10-14 d of intravenous antibiotic treatment for a pulmonary exacerbation. Results: After treatment, respiratory status improved (percentage of forced expiratory volume in 1 s: 60 ± 6% at baseline compared with 74 ± 7% after treatment, P = 0.01), quality of well-being improved (P = 0.001), and total plasma 8-iso-PGF2α concentrations increased from 469 nmol/L at baseline (interquartile range: 373-554 nmol/L) to 565 nmol/L after treatment (interquartile range: 429-689 nmol/L; P = 0.008). Total energy, fat, carbohydrate, and protein intakes per kilogram body weight also increased; however, dietary antioxidant intake was unchanged. Plasma fatty acid concentrations increased after treatment, strongly correlating with plasma 8-iso-PGF2α concentrations (r = 0.768, P = 0.001). There were no significant changes in white cell counts or plasma concentrations of vitamins E and C or β-carotene. Erythrocyte glutathione peroxidase activity was reduced after treatment, whereas there was no significant change in superoxide dismutase activity. Conclusions: Oxidative stress increased after treatment for pulmonary exacerbations and was strongly linked to increased concentrations of plasma fatty acids. Although intravenous antibiotic therapy and physiotherapy improved lung function within 10-14 d of treatment, the biochemical effects of oxidation continued further. Thus, antioxidant intervention during treatment for and recovery from acute infection in cystic fibrosis should be considered.