Mechanism of the development of pulmonary emphysema

It is generally accepted that pulmonary emphysema is a consequence of proteinase-antiproteinase imbalance in the lungs, which can be induced by cigarette smoking. Recognition that elastic fiber destruction is probably a central feature in the pathogenesis of smoking-induced emphysema has focused attention on elastolytic enzymes that might be involved. The lungs contain a number of elastolytic enzymes that mainly originate from inflammatory cells such as neutrophils or macrophages that have emigrated into the lungs. Accordingly, it has long been debated which cell and/or which proteinase is mainly responsible for the mechanism of parenchymal destruction associated with cigarette smoking. Structural cells in the lungs such as epithelial cells and endothelial cells may also be involved in cell death and repair. Individual genetic background may regulate the function of these cells in response to cigarette smoke and is related to the susceptibility to pulmonary emphysema.