Phospholipase C sensitive FVII activity and FVII antigen in hypertriglyceridemia

An increase in factor VII coagulant activity (FVIIc) was found in patients with high thrombotic risk and in hyperlipidemias, namely in Fredrickson's types IIb and IV. This elevation was correlated with the level of total cholesterol and triglyceride concentrations. It has been suggested that this increase is due to higher FVII coagulant activity related to the formation of a complex between factor VII (FVII) and phospholipids, since it was shown that FVIIc returns to normal levels after incubation of plasma with phospholipase C. In this respect we have studied the activity of FVII before and after phospholipase C plasma treatment and FVII related antigen (FVIIag) in patients with types IIa, IIb and IV hyperlipidemias. An elevation of FVIIc was found in hyperlipidemic patients compared to normal controls. FVIIag values were also higher in type IV patients, implicating an increase in FVII total concentration and not only an activation of FVII. Furthermore, Phospholipase C action on patients' plasma samples lowered FVIIc to levels very similar to those of FVIIag. In normal controls the same action was noted and it seems therefore likely that the proposed phospholipid contribution to FVIIc hyperactivity plays only a minor role in FVII changes in primary hyperlipidemia. Instead, FVIIag increase seems to be the major mechanism of FVII increase in primary hypertriglyceridemic patients.