Patients with cystic fibrosis (CF) show elevated levels of oxidative stress in their serum, according to a study published in Antioxidants. These levels tended to increase with patient age and the severity of the disease.

Elevated levels of both protein and lipid oxidation products were detected in patients with CF, compared to healthy controls, during the study. The promising biomarker for protein oxidation, 3-nitrotyrosine, which is formed when reactive peroxynitrite molecules cause the nitration of protein and free tyrosine residues, was significantly elevated in the CF group (0.13 ± 0.02 vs 0.11 ± 0.01 nmol/mg protein; P =.0001).

In addition, some biomarkers of lipid peroxidation were found to be elevated in the patients with CF. Malondialdehyde (MDA) levels in CF patients were 3.47 ± 0.5 μmol/L compared to 3.17 ± 0.28 μmol/L in healthy controls (P =.025). The levels of 8-isoprostane were also found to be elevated, with values of 110.71 ± 35.74 pg/mL in patients compared to 85.18 ± 37.33 pg/mL in controls (P =.024).

When divided into subcategories of disease severity, the total antioxidant capacity (TAC) measured by both ABTS assay and ferric reducing antioxidant power assay (FRAP) were found to be statistically lower between patients in the severe CF category and healthy controls (P =.031 and P =.03, respectively). Patients with moderate or severe CF had significantly higher levels of 8-isoprostane and 3-nitrotyrosine compared to healthy controls. Thiol group concentrations were also found to be reduced in those with severe CF, compared to those with mild CF and healthy controls.

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Weak to moderate correlations between age and advanced oxidation protein products (AOPP; R=0.47; P =.003), 3-nitrotyrosine (R=0.373; P =.025) and MDA (R=0.368; P =.025) were found.

Patients with CF and bacterial infections also showed changes in oxidative stress levels. Active infection with Pseudomonas aeruginosa resulted in an elevation in 3-nitrotyrosine levels (P <.05) and infection with Staphylococcus aureus was linked to decreases in thiol group levels (P <.05).

“In summary, elevated levels of oxidative stress, including products of protein and lipid oxidation, as well as decreased total antioxidant capacity, were found in the serum of people with CF. Moreover, the level of oxidative stress increased with age and severity of the disease,” the authors concluded.

A total of 42 patients with CF (20 female and 22 male) and 16 healthy controls (10 female and 6 male) were included in the study. No difference was observed in terms of age and height were observed between the 2 groups, however, the CF group had statistically lower weight (P <.05) and BMI (P <.01) than the healthy controls.


Galiniak S, Mołoń M, Rachel M. Links between disease severity, bacterial infections and oxidative stress in cystic fibrosis. Antioxidants. 2022;11(5):887. doi:10.3390/antiox11050887