A novel form of factor VII in plasma from men at risk for cardiovascular disease.

In the Northwick Park Heart Study high activity of the coagulation factor VII was associated with cardiovascular deaths. We confirm here that men at high risk for such disease have increased levels of factor VII activity and demonstrate for the first time that this is due to a phospholipid-factor VII complex in their plasma. This complex increases the specific activity of its factor VII significantly. It is not inhibited by a neutralizing antiserum to thromboplastin and thus does not represent a factor VII-thromboplastin complex. Gel filtration data suggest an apparent Mr of 66-72 000 for the complex. Factor VII in this phospholipid complex is more sensitive than native factor VII to the serine protease inhibitor diisopropyl-fluorophosphate, consistent with a more accessible active site conformation (and a higher specific activity) for factor VII in the complex. The level of phospholipid-factor VII complex showed a significant positive correlation with plasma triglycerides and correlation of borderline significance with cholesterol.