Reactive Oxygen Species in Peripheral Blood and Sputum Neutrophils During Bacterial and Nonbacterial Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Abstract

Chronic airway inflammation can be mediated by an enhanced neutrophil oxidative burst. However, the role of bacteria in the pathogenesis of chronic obstructive pulmonary disease (COPD) exacerbations is highly controversial. The aim of this study was to evaluate the production of reactive oxygen species (ROS) in peripheral blood and sputum neutrophils during bacterial and nonbacterial acute exacerbations of COPD (AECOPD). A total of 40 patients with AECOPD, 10 healthy nonsmokers, and 10 "healthy" smokers were enrolled into the study. Peripheral blood and sputum samples were obtained during exacerbation and after recovery. Neutrophils were isolated by high-density gradient centrifugation and magnetic separation. ROS production by neutrophils was investigated after stimulation with phorbol-myristate-acetate and Staphylococcus aureus bacteria. ROS production by neutrophils was assessed as the mean fluorescent intensity using a flow cytometer. IL-8 levels in serum and induced sputum were determinant by ELISA. Spontaneous ROS production was significantly higher in neutrophils from the patients with bacterial AECOPD as compared with nonbacterial AECOPD and stable COPD (P <0.05). ROS production stimulated with PMA and with Staphylococcus aureus was significantly higher in neutrophils isolated from the patients with bacterial AECOPD as compared with nonbacterial and stable COPD (P <0.05). The serum and induced sputum IL-8 levels were significantly increased in the patients with bacterial AECOPD than nonbacterial AECOPD, stable COPS, and "healthy" smokers and nonsmokers (P <0.05) and higher in the induced sputum as the compared with serum in all studied groups (P <0.05). Enlarge CRP level was documented during AECOPD than in all other groups (P <0.05). A markedly increased ROS production in sputum neutrophils during bacterial AECOPD shows an inflammatory response reflecting enhanced local inflammation, which can be mediated by bacterial colonization.

Shared mechanisms of multimorbidity in COPD, atherosclerosis and type-2 diabetes: the neutrophil as a potential inflammatory target

“…ROS are known to cause damage in biological systems, including within settings of chronic inflammation [147], and are linked to ageing as described by the free radical theory of ageing [148]. Neutrophils have enhanced ROS responses in patients with COPD, especially with bacterially induced exacerbations [149,150]. Raised markers of oxidative stress have been identified in the sputum and plasma of patients with COPD, related to increased ROS and also decreased antioxidant activity [151].…”

Impaired Blood Neutrophil Function in the Frequent Exacerbator of Chronic Obstructive Pulmonary Disease: A Proof-of-Concept Study

“…Blood neutrophils also show an altered pattern of activity in the stable state in COPD, with impaired chemotaxis and reduced intracellular reactive oxygen species (ROS) production [14–16]. Evidence of further systemic immune dysregulation occurs during exacerbations with circulating neutrophils displaying up-regulation of inflammation-related genes, enhanced expression of cell adhesion molecules and elevated production of elastase and ROS [17–20]. Despite an abundance of data supporting the hypothesis that neutrophils are key effector cells in the development and progression of COPD [13], we could find no studies assessing blood neutrophil function of COPD patients according to exacerbation history.…”

Increased Reactive Oxygen Species (ROS) as Aberrant Neutrophil Function among Healthy Smokers with High Cigarette Smoking Profile and Chronic Obstructive Pulmonary Disease Patients

“…16,22 Viatkus and colleagues reported that increased ROS production of peripheral blood and sputum-derived neutrophils among COPD were associated with the exacerbation of COPD. 23,24 Although plenty of data suggest that tobacco use is one of the main factors contributing to COPD and respiratory tract inflammation, approximately 20% of smokers developed disease. [2][3][4] This work aims to determine the phenotypic change of circulating neutrophils, including intracellular ROS and phagocytosis among different tobacco consumption smokers compared to COPD patients.…”

“…The quantity of ROS was traced using 2´,7´-dichlorofluorescin diacetate (DCFH-DA). 16,23 Briefly, polymorphonuclear cells were removed from heparinized blood by density gradient centrifugation (Isoprep TM ). Neutrophils were collected by 3% dextran sedimentation.…”