Plasminogen activators and plasminogen activator inhibitors in plasma of premature and term newborns

Objective : To compare the plasminogen activators (tPA, uPA) and their inhibitors (PAI-1, PAI-2) at different gestational ages, related to levels in women at term and non-pregnant women. Methods : Blood samples were obtained by puncture of the umbilical cord vein, in gestational weeks 39–40 ( n = 21), 30–32 ( n = 15), and 27–29 ( n = 9). Analyses of PA and PAI antigen concentrations and of PAI-1 activity were performed. Results : The mean tPA antigen level in term newborn infants was 14.5 μg/l compared to the premature newborns (7.0 μg/l) women at term (7.5 μg/l) and non-pregnant women (2.3 μg/l). PAI-1 activity and PAI-2 antigen concentrations were also higher in term newborn than in premature infants. Conclusions : The plasma levels of the plasminogen activators and inhibitors are higher in term newborn compared with premature newborn infants, reflecting maturation of protein synthesis.