ABSTRACT
Oxidants, inflammation, repair, fibrosis, proteolysis and tissue remodelling Following chronic exposure to oxidants in cigarette smoke and other inhaled noxious agents, patients with COPD have an amplified inflammatory response in the airways and lung parenchyma (Figure 2.1). Epithelial cell injury and macrophage activation cause release of chemotactic factors that recruit neutrophils from the circulation. Macrophages and neutrophils then release proteases, with involvement of matrix metalloproteinases (MMPs) and neutrophil elastase (NE) which break down connective tissue. Cytotoxic CD8+ T cells may also be involved in this inflammatory cascade. Over many years of injury, cycles of inflammation and repair occur which may result in resolution, but which can be associated with proteolysis, fibrosis, and both airway and parenchymal remodelling.
