Postprandial triglycerides and blood coagulation

Most of our lifetime we spend in the postprandial state. Postprandial trigl yceridemia may represent a procoagulant state involving disturbances of bot h blood coagulation and fibrinolysis, in particular due to elevation of the plasma levels of activated factor VII (VIIa) and plasminogen activator inh ibitor (PAI-1). Therefore. disturbances of the hemostatic system might, at least partly, account for by the link between hypertriglyceridemia and coro nary heart disease (CHD). - Factor VIIa is the first enzyme of the blood co agulation system and serves a priming function for triggering of the clotti ng cascade. The coagulant activity of factor VII (VIIc, total activity of f actor VII in plasma) was identified as an independent predictor of myocardi al infarction in initially healthy middle-aged men. and particularly of Fat al coronary events. and both serum cholesterol and triglyceride concentrati ons correlated positively with the VIIc level. Addition of fat to diet has been consistently shown to cause a rapid conversion of the factor VII zymog en into its active form (VIIa) whereas the concentration of total protein i s unaffected. Postprandial activation of factor VII is dependent on lipolyt ic activity and it is mainly supported by large triglyceride-rich lipoprote in of the VLDL class. Studies in vivo with specific coagulation factor-defi cient patients indicate that factor IX is essential for the postprandial ac tivation of factor VII. The basal generation of thrombin seems to be unaffe cted by increased plasma levels of VIIa. However, since VIla-tissue factor complex is responsible for the initiation of the coagulation cascade, incre ased generation of VIIa in the post prandial state would increase the poten tial for thrombin production in the event of plaque rupture. - Plasminogen activator inhibitor-1 (PAI-1) is the major physiological inhibitor of the p lasminogen activators in the circulation and thereby the: principal inhibit or of the fibrinolytic system. Postprandial triglyceridemia has been observ ed in many. not all. studies to increase PAI-1 plasma levels, which would f urther strengthen the chances of thrombotic occlusion of a vessel after rup ture of an atherosclerotic plaque.