Hepatic and splanchnic metabolism of plasma proteolytic enzymes before, during, and after clamping of the hepatic artery and portal vein.
Parameters of the kallikrein-kinin, fibrinolytic, and coagulation systems before (control), during, and after occlusion of the hepatic artery and the portal vein were studied in anesthetized pigs. Hepatic synthesis was observed for kallikrein, plasmin, and plasminogen. The other factors, prekallikrein, kallikrein inhibitor, alpha 2-antiplasmin, prothrombin, and antithrombin-III were all released by the liver and underwent partial hepatic inactivation. The splanchnic area showed a significant synthesis of antithrombin-III. After 90 min of hepatic arterial occlusion, the hepatic release of all factors declined, and synthesis of kallikrein, plasmin, and plasminogen fell an average of 54%. The inactivation of prekallikrein and alpha 2-antiplasmin was increased and the splanchnic synthesis of antithrombin-III fell. Portal vein blood flow fell by 38%. After 15 min of portal vein occlusion (combined occlusion of the hepatic artery and portal vein) the splanchnic area started to synthetize kallikrein and the hepatic inflow of kallikrein increased by more than 50%. Splanchnic metabolism of other factors was also altered, but after revascularization of the hepatic artery changes were mostly insignificant. Hepatic synthesis of kallikrein and plasmin remained depressed after reperfusion, and that of plasminogen fell to zero. After this short period of occlusion of the hepatic artery and portal vein, plasma concentrations of prekallikrein, plasmin, and alpha 2-antiplasmin were decreased, causing a state of fibrinolysis. A role for kallikrein/bradykinin in hepatic blood flow regulation is proposed and implications of these observations for liver transplantation are discussed.
Omland
E
E
Department of Surgery B, National Hospital, Rikshospitalet, Oslo, Norway.
Mathisen
O
O
D000818:Animals; D001157:Arterial Occlusive Diseases / Q000201:enzymology / Q000378:metabolism; D003250:Constriction; D010450:Endopeptidases / Q000097:blood*; D006439:Hemodynamics; D006499:Hepatic Artery / Q000601:surgery*; D008099:Liver / Q000201:enzymology*; D016031:Liver Transplantation; D011169:Portal Vein / Q000601:surgery*; D013152:Splanchnic Circulation / Q000502:physiology*; D013552:Swine; D013997:Time Factors
D010450:Endopeptidases