Placenta and Myometrium – The Two Main Sources of Fibrinolytic Components during Pregnancy

Abstract

Objectives: Placenta is a known source of some fibrinolytic components in pregnancy. The aim of the present study is to find out whether myometrium can be a parallel source. Study Design: The study group consisted of 34 women (16 primaparas and 18 multiparas, 39.0 ± 0.2 years) in the 36–40th week of gestation with some obstetric complications: preeclampsia – 11, fetal distress – 9, breech presentation – 3, placenta previa – 1, repeat caesarean birth – 10 cases (20 women were the control group). The strips of myometrium as well as samples of venous blood and placenta were collected at the time of caesarean section. The tissue extracts were prepared. The components of the plasminogen activator system were measured, i.e. tissue plasminogen activator (tPA), urokinase plasminogen activator (uPA), plasminogen activator inhibitor 1 (PAI-1) and plasminogen activator inhibitor 2 (PAI-2). An immunoenzymatic method (ELISA) was used. Spearman and Pearson’s correlation coefficients were the main tools of the statistical analysis. Results: The concentration of the fibrinolytic components in blood plasma, placenta and myometrium were as follows (ng/mg of total protein): tPA: 0.15 ± 0.07 (blood plasma), 0.12 ± 0.05 (placenta), and 1.42 ± 1.02 (myometrium); uPA: 0.01 ± 0.005 (blood plasma), 1.09 ± 0.25 (placenta), and 0.52 ± 0.13 (myometrium); PAI-1: 2.86 ± 0.90 (blood plasma), 30.67 ± 9.31 (placenta), and 22.29 ± 11.29 (myometrium); PAI-2: 2.86 ± 0.90 (blood plasma), 750.89 ± 170.29 (placenta), and 24.84 ± 8.03 (myometrium). Conclusion: Besides placenta, myometrium is another important source of fibrinolytic components in pregnancy.