Proteinase-antiproteinase imbalance

There are several other factors that may play a role in the development of emphysema in ai-PI-sufficient individuals, however, one can conclude that the proteinase-antiproteinase imbalance is involved, as in the case of hereditary emphysema. If the protective shield of the lung is diminished either due to oxidative or proteolytic inactivation of inhibitors, then uncontrolled elastinolytic activity will occur resulting in tissue damage (Fig. 1). This protective shield can... 

Proteinases and antiproteinases are part of the normal protective and repair mechanisms in the lungs. The imbalance of proteinase-antiproteinase activity in COPD is a result of either increased production or activity of destructive proteinases or inactivation or reduced production of protective antiproteinases. AAT (an antiproteinase) inhibits trypsin, elastase, and several other proteolytic enzymes. Deficiency of AAT results in unopposed proteinase activity, which promotes destruction of alveolar walls and lung parenchyma, leading to emphysema. 

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