The relationship between lung function, exercise capacity, oxidant and antioxidant response in primary ciliary dyskinesia and cystic fibrosis

Background. There is a need to identify the complex interplay between various physiological mechanisms in primary ciliary dyskinesia (PCD) and cystic fibrosis (CF). The study investigated the interaction between respiratory function, exercise capacity, muscle strength, and inflammatory and oxidant/antioxidant responses in patients with PCD and CF. Methods. The study included 30 PCD patients, 30 CF patients, and 29 age and sex-matched healthy subjects. Exercise capacity was assessed using the modified shuttle walk test (MSWT). Handgrip strength (HGS) was used to evaluate general muscle strength. Oxidative stress-inflammatory parameters were also assessed. Pulmonary function test was performed by spirometry. Regarding the forced expiratory volume in 1 second (FEV1) z-score, patients with PCD and CF were subdivided into normal, mild, and severe/moderate groups. Results. Forced vital capacity (FVC) z-scores were lower in PCD and CF patients than controls. FEV1, FEV1/FVC, peak expiratory flow (PEF), and forced mid expiratory flow (FEF_25-75%) z-scores were lower in PCD than in the other groups. HGS was lower in both mild PCD and normal CF patients relative to the controls. MSWT distance was lower in severe/moderate PCD patients than controls. Catalase (CAT), glutathione S-transferase (GST), glutathione peroxidase (GPx), and malondialdehyde (MDA) levels did not differ significantly among the study groups, but superoxide dismutase (SOD) level in severe/moderate PCD, and glutathione (GSH) level in normal CF were higher than in controls. Interleukin-6 (IL-6) level was higher in patients with normal PCD and CF compared to the controls. IL-1β level was higher in PCD compared to controls. Additionally, correlations among these parameters were also determined in some patient groups. Conclusion. Homeostasis related to respiratory function, aerobic performance, muscle strength, inflammatory response, and oxidant/antioxidant balance were affected in PCD and CF. Evaluating these mechanisms together may contribute to elucidating the pathophysiology of these rare diseases.