Summary

Tissue plasminogen activator (t-PA) and plasminogen activator inhibitor 1 (PAI-1) directly influence thrombus formation and degradation and thus risk for arterial thrombosis. We report here results from a genetic analysis of plasma t-PA and PAI-1 levels in a large population-based sample from the PREVEND study in Groningen, the Netherlands (n=2,527). We measured polymorphisms from genes of the fibrinolytic system, the reninangiotensin system (RAS), and the bradykinin system.We found that males had higher levels of natural-log transformed t-PA, and PAI-1 (P < 0.01) compared to females.When stratifying females by menopausal status, PAI-1 levels were only significantly different between pre-menopausal females and males (p<0.001). Furthermore, we found that age, body mass index, and waist-to-hip ratio were significant predictors of t-PA and PAI-1 in both females and males, and that the regression relationships between these factors and plasma t-PA and PAI-1 were dependent on gender.In addition,we found that the PAI-1 4G/5G polymorphism was a significant predictor of PAI-1 levels in both females and males, that the angiotensin II type I receptor A1166C was a significant predictor of t-PA and PAI-1 levels in females, and that the bradykinin receptor B2 58CT polymorphism was a significant predictor of t-PA levels in females. In conclusion, this large population- based study showed that t-PA and PAI-1 levels are determined by several demographic and genetic factors involved in the fibrinolytic, RAS and bradykinin system. In addition, the results support the idea that the biology of t-PA and PAI-1 is different between females and males.