Fig. 1

Events caused by oxidative stress and reactive oxygen species (ROS) production in patients with COPD. Oxidative stress occurs in response to inhaled oxidants from environmental sources and excess production of cellular ROS, leading to an imbalance between oxidants and antioxidants in favour of oxidants. The ROS cause lipid peroxidation and oxidative damage to proteins and DNA, as well as activation of cells and signal transduction pathways that trigger inflammatory mediator release and protease activation, which sustain the oxidative stress. AP-1 activated protein-1, COPD chronic obstructive pulmonary disease, COX-2 cyclooxygenase-2, cPLA₂ cytosolic phospholipase A2, c-Src cellular Src (a non-receptor tyrosine kinase protein), DNA deoxyribonucleic acid, EGFR epidermal growth factor receptor, ICAM-1 intracellular adhesion molecule-1, MAPK mitogen-activated protein kinase, MMP-9 matrix metalloproteinase 9, NF-κB nuclear factor-κappaB, PDGFR platelet-derived growth factor receptor, PI3Kδ phosphoinositide-3-kinase-delta, PKC protein kinase C, ROS reactive oxygen species, VCAM-1 vascular cell adhesion molecule 1