SYSTEMIC INFLAMMATION AND OXIDATIVE STRESS IN BRONCHIECTASIS PATIENTS WITH SARCOPENIA: IMPLICATIONS FOR MUSCLE FUNCTION AND PULMONARY REHABILITATION STRATEGIES

Sarcopenia is common in chronic respiratory diseases. Several biological processes are involved in its onset. In the muscles of patients with non-cystic fibrosis bronchiectasis, the underlying mechanisms have not yet been described. We hypothesized that markers of inflammation and oxidative stress are elevated in this patients. To assess nutritional status, pulmonary and muscle function, markers of inflammation and oxidative stress, and correlations between biological and clinical variables. In blood samples from 20 stable patients with bronchiectasis and functionally confirmed sarcopenia and 10 healthy subjects, the following biomarkers were quantified: 1. Oxidants and antioxidants: 3-nitrotyrosine, protein carbonylation, malondialdehyde protein adducts, Trolox equivalent antioxidant capacity (TEAC), reduced glutathione (GSH), superoxide dismutase (SOD) activity, and catalase activity. 2. Systemic inflammation: myeloperoxidase, cyclooxygenase-2 (COX-2), transforming growth factor beta 1 (TGF-β1), vascular endothelial growth factor A (VEGF-A), and interleukin-6 (IL-6), using ELISA. Compared to controls, patients with bronchiectasis showed significantly reduced body composition, lung function, and muscle function (sarcopenia). Systemic levels of inflammation biomarkers, oxidants, and antioxidants were significantly increased in patients. In these patients, quadriceps strength and handgrip strength were negatively correlated with systemic levels of 3-nitrotyrosine (r = -0.558, p = 0.013), SOD (r = -0.454, p = 0.044), and IL-6 (r = -0.520, p = 0.022), respectively. This study demonstrates that in bronchiectasis, sarcopenia affects both upper and lower limb muscles. The increased systemic levels of oxidative stress and inflammation, along with their correlations with muscle strength, suggest these factors are likely involved in the pathophysiology. These findings could be important for designing therapeutic strategies in pulmonary rehabilitation.