Skeletal muscle dysfunction is common in many chronic respiratory diseases. Several clinical and biological factors contribute to its etiology. Acute exacerbations and systemic inflammation and oxidative stress are mostly responsible. Whether patients with bronchiectasis experience limb muscle dysfunction remains to be fully elucidated as well as the underlying mechanisms. In vastus lateralis (VL) of patients (n=20) with bronchiectasis and 10 healthy controls phenotypic features and in blood samples parameters of inflammation and oxidative stress were evaluated along with muscle function (upper and lower limbs). In bronchiectasis patients compared to controls, upper and lower limb muscle function and fast-twitch muscle fiber cross-sectional area were reduced, while systemic levels of myeloperoxidase, TGF-?1, VEGF-A, IL-6, protein carbonylation, superoxide dismutase activity, and reduced glutathione significantly increased. Muscle dysfunction of the upper and lower limbs in bronchiectasis patients is a relevant clinical feature, in which systemic inflammation and oxidative stress together with the predominance of a fast-twitch phenotype underlie its pathophysiology. These findings may have clinical implications when designing specific therapeutic strategies.

Funding: FIS 21/00215 (FEDER, ISC-III), Intensificación INT19, CIBERES (ISC-III), SEPAR-2020.