Characterization of iron deficiency in COPD patiens: implications in exercise tolerance and redox balance in muscle and systemic compartments
Year: 2023
Type: dissertation
Abstract: Chronic obstructive pulmonary disease (COPD) patients may present different types of systemic manifestations. Iron deficiency (ID) (Fe, an essential nutritional element) is common and can negatively affect exercise tolerance and, therefore, their quality of life. The objectives of this thesis were to study the effects of ID on exercise capacity and lung function in patients with severe COPD and muscle dysfunction. Forty COPD patients (n=20 without ID and n=20 with ID) were recruited, from whom blood and muscle specimens (vastus lateralis, VL) were obtained. Lung function, exercise capacity (6-minute walk test, 6MWT), and limb muscle strength were assessed in all patients. In addition, the levels of biomarkers of iron metabolism regulators, oxidative stress (blood and muscle) and muscle architecture was analyzed. Correlations between clinical and biological variables were performed. Besides, in the current thesis, another objective was to evaluate the effect of iron replacement on oxidative stress in ID COPD patients. For this study, 66 ID COPD patients were recruited (n=22 treated with placebo and n=44 treated with ferric carboxymaltose). Biomarkers of iron metabolism and oxidative stress were analyzed in the blood of these patients, before and after treatment. Among all COPD patients (with and without ID), serum ferritin levels correlated with FEV1. In ID COPD patients, their exercise capacity was reduced; likewise, the 6MWT distance was positively associated with iron metabolism regulators (ferritin, hepcidin, and muscle iron content). In the VL of ID patients, the percentage of type I fibers decreased, while the percentage of type II fibers increased. Moreover, in these patients the systemic and muscle levels of pro-oxidant markers were increased, meanwhile antioxidants were reduced. In ID COPD patients, after iron replacement therapy, systemic oxidative stress markers were attenuated. In conclusion, in COPD patients, exercise capacity and lung function are associated with the content of iron metabolism regulators. In addition, in these patients, oxidative stress levels seem to be related to iron availability, increasing in the case of iron deficiency and improving in the case of iron replacement treatment.
Author: Pérez Peiró, Maria
Language: English
Subfield: Hematology
Field: Medicine
Domain: Health Sciences
Open Access status: green
Award: G1262562143
OpenAlex ID: W7064350542