[Interaction of proteases and their inhibitors in the pathogenesis of pancreatitis]

It was confirmed that esterolytic activity was significantly elevated in plasma of patients with acute pancreatitis, which correlated better with the stage of the disease than serum amylase level. Using the several column chromatography procedures, pancreatic kallikrein, trypsin and pancreatic elastase were separated and purified from alpha 2-macroglobulin (alpha 2-M) fractions of patients plasma with acute pancreatitis. From this this result, it was confirmed that kallikrein was liberated into the blood stream from the pancreas during attacks of acute pancreatitis and the liberated kallikrein combined with alpha 2-M. Furthermore, the coexistence of trypsin is required for the complex formation of alpha 2-M and pancreatic kallikrein. It was speculated that alpha 2-M might be decomposed by the excessive amount of elastase, and consequently, might release all of its combining enzymes into the blood stream. In the present study, the activation mechanism of fibrinolytic enzyme system in plasma by human pancreatic elastase was investigated. Elastase not only converted the co-existing plasminogen to low molecular weight plasminogen which could be easily activated by the activators, but also inhibited alpha 2-M and alpha 2-plasmin inhibitor, and consequently, induced the activation of the fibrinolytic enzyme system in plasma. Furthermore, it was also confirmed that elastase could activate plasma kallikreinogen to kallikrein.