Relationship between fibrinolytic and metabolic variables: a study in patients attending a lipid clinic

We investigated the relationship between plasma levels of metabolic and fib rinolytic variables in 163 fasted patients attending a lipid clinic. Of the se patients, 118 had hypertriglyceridaemia (HTG) and 45 had normotriglyceri daemia (NTG). In HTG, basal fibrinolytic activity, ie tissue plasminogen ac tivator (t-PA) activity, was impaired as a result of high plasminogen activ ator inhibitor type 1 (PAI-1) antigen and activity Multiple stepwise regres sion analysis identified insulin and triglyceride levels as independent det erminants of plasma PAI-1 levels (R-2 = 0.18; P = 0.0001). When the patient s were stratified into tertiles according to their levels of triglyceride a nd insulin, PAI-1 antigen levels were found to increase with rising levels of triglyceride in each insulin tertile. In contrast, the increase of PAI-1 with rising insulin levels was evident in the highest triglyceride tertile . In addition, subjects in the lowest tertile of both triglyceride and insu lin had the lowest PAI-1 antigen levels, and subjects in the highest tertil e of both triglyceride and insulin had the highest levels of PAI-1. Both ba sal and stimulated levels of t-PA antigen were significantly higher in HTG than in NTG. Multiple stepwise regression analysis identified triglyceride level as the sole major determinant of t-PA antigen levels (R2 = 0.13; P = 0.00003). The observation that both insulin and triglycerides correlate wit h PAI-1, whereas triglycerides were involved only in the increased secretio n of t-PA, suggests that these two proteins are regulated by different mech anisms.