Systemic inflammation and oxidative stress in bronchiectasis-associated sarcopenia

Sarcopenia has recently been associated with bronchiectasis. We hypothesised that inflammation and oxidative stress are elevated in both systemic and muscle compartments in patients with bronchiectasis-associated sarcopenia, even in the absence of acute exacerbations.

We analysed proinflammatory and redox balance biomarkers in blood (ELISA) and vastus lateralis (VL) muscle tissue (immunoblotting, real-time PCR) from 20 sarcopenic patients with stable bronchiectasis and 10 healthy controls. All participants underwent clinical and functional assessments. Exploratory associations between clinical parameters and biological markers were also examined.

Compared to controls, bronchiectasis patients exhibited a decline in body mass index, fat-free mass index, muscle function (upper and lower limbs), lung function and exercise capacity, whereas a significant rise in plasma levels of the biomarkers vascular endothelial growth factor, transforming growth factor-β1, interleukin (IL)-6, IL-8, IL-1β, tumour necrosis factor-α, myeloperoxidase, reactive carbonyls, superoxide dismutase (SOD) activity and glutathione (GSH) was observed. Positive correlations were encountered between inflammatory cytokines and leukocytes and neutrophils, while negative associations were observed between sarcopenia degree and SOD activity and GSH plasma levels. In VL, levels of the analysed biomarkers did not differ between patients and controls.

Increased inflammation and oxidative stress in the systemic compartment, but not in muscle, were observed in sarcopenic patients with mild-to-moderate bronchiectasis, and were also associated with impaired muscle and nutritional status. These findings emphasise the importance of a holistic treatment approach that addresses both pulmonary and systemic manifestations of the disease. Interventions targeting inflammation and oxidative stress, including rehabilitation and antioxidant therapies, may help improve outcomes and warrant further investigation as potential therapeutic strategies.