Effects of endurance training on pulmonary and systemic levels of interleukin-8 in patients with stable COPD

Abstract

Background: Patients with Chronic Obstructive Pulmonary Disease (COPD) may show increased levels of interleukin (IL)-8 (CXCL8). Respiratory physiotherapy may reduce IL-8 in induced sputum, but no information is available about the potential effects of endurance training on systemic or pulmonary levels of IL-8.

Objective: To investigate the effects of endurance training on pulmonary and systemic levels of IL-8 in patients with stable COPD.

Methods: Levels of IL-8 were quantified in plasma and induced sputum (ELISA) in a group of patients with moderate to severe stable COPD (study group [S]: n=6, 64±4 [mean±SD] years, FEV1: 49.5±14.2% pred. post-bd.) before and after an 8 weeks controlled endurance training program, and in a control group ([C]: n=5, 61±5 years, FEV1: 45.4±9.6% pred. post-bd.), who did not perform such a program.

Results: After 8 weeks, levels of IL-8 in plasma (S: from 4.2±4.3 to 3.9±4.0 pg/mL; C: from 4.4±1.2 to 6.5±6.2 pg/mL) and sputum (S: from 2217.1±1555.8 to 4153.2±3024.5 pg/mL; C: from 3012.88±1593.03 to 2599.92±1200.12 to pg/mL), remained unchanged in either group, despite that S showed, respectively, an increase of peak oxygen consumption (from 1.1±0.3 to 1.2±0.3 L/min, p=0.04), and a decrease of lactic acid levels at peak exercise (from 5.5±1.0 to 4.2±0.7 mmol/L, p<0.05).

Conclusions: In patients with stable COPD, a controlled endurance training program does not modify the pulmonary and/or systemic levels of IL-8. Hence, the beneficial effects of physical training cannot be attributed to the reduction of systemic pro-inflammatory cytokines.