Serum Free Radical Scavenging Capacity Profiles of Patients with Chronic Obstructive Pulmonary Disease

Oxidative stress is an important mechanism for the development and progression of chronic obstructive pulmonary disease (COPD). It may also contribute to systemic manifestation in patients with COPD. Reactive oxygen species (ROS) including free radicals play a crucial role in oxidative stress in COPD. The aims of this study were to determine serum scavenging capacity profile against multiple free radicals and to evaluate its correlation with pathophysiology, exacerbations, and prognosis in patients with COPD.

Serum scavenging capacity profile against multiple free radicals comprising hydroxyl radical (^•OH), superoxide radical (O₂ ^-•), alkoxy radical (RO^•), methyl radical (^•CH₃), alkylperoxyl radical (ROO^•), and singlet oxygen (¹O₂) was assessed using the multiple free-radical scavenging method in 37 patients with COPD (mean age, 71 years; mean forced expiratory volume in 1 s, 55.2% predicted). The severity of emphysema was evaluated by Goddard classification on chest computed tomography. Exacerbations were recorded prospectively for 1 year and the overall mortality was assessed 5 years after the initial assessment.

^•OH scavenging capacity was significantly decreased (p < 0.05) and O₂ ^-• and ^•CH₃ scavenging capacity tended to decrease in patients with COPD compared to that in healthy controls. On the other hand, ROO^• scavenging capacity tended to increase. In addition, RO^• scavenging capacity was associated with severity of emphysema (p < 0.05) and exacerbation frequency (p < 0.02). There was a difference in the profile of the scavenging capacity between survived and deceased patients with COPD for 5 years after initial assessment.

Characteristic profile of free radical scavenging capacity can provide insight into the pathophysiology and prognosis of patients with COPD.