Syncytiotrophoblast microvesicles released from pre-eclampsia placentae exhibit increased tissue factor activity.

BACKGROUND: Pre-eclampsia is a complication of pregnancy associated with activation of coagulation. It is caused by the placenta, which sheds increased amounts of syncytiotrophoblast microvesicles (STBM) into the maternal circulation. We hypothesized that STBM could contribute to the haemostatic activation observed in pre-eclampsia. METHODOLOGY/PRINCIPAL FINDINGS: STBM were collected by perfusion of the maternal side of placentae from healthy pregnant women and women with pre-eclampsia at caesarean section. Calibrated automated thrombography was used to assess thrombin generation triggered by STBM-borne tissue factor in platelet poor plasma (PPP). No thrombin was detected in PPP alone but the addition of STBM initiated thrombin generation in 14/16 cases. Pre-eclampsia STBM significantly shortened the lag time (LagT, P = 0.01) and time to peak thrombin generation (TTP, P = 0.005) when compared to normal STBM. Blockade of tissue factor eliminated thrombin generation, while inhibition of tissue factor pathway inhibitor significantly shortened LagT (p = 0.01) and TTP (P<0.0001), with a concomitant increase in endogenous thrombin potential. CONCLUSIONS/SIGNIFICANCE: STBM triggered thrombin generation in normal plasma in a tissue factor dependent manner, indicating that TF activity is expressed by STBM. This is more pronounced in STBM shed from pre-eclampsia placentae. As more STBM are shed in pre-eclampsia these observations give insight into the disordered haemostasis observed in this condition.

Acute and chronic Chlamydia pneumoniae infection in pregnancy complicated with preeclampsia.

OBJECTIVE: To investigate whether Chlamydia pneumoniae (Cp) infection is more common in women whose current pregnancy is complicated with preeclampsia (PE) as compared to pregnant women without PE. METHODS: Thirty pregnant women with PE and 30 pregnant women without PE were studied between 29 and 30 weeks of gestation. The presence of an acute or chronic Cp infection was determined by the estimations of serum IgG, IgM, and IgA Cp antibodies. RESULTS: None of the women were diagnosed as having acute Cp infection. Prevalence of chronic Cp infection was 53 and 66% in the PE and control groups, respectively (X(2), p = 0.068). CONCLUSION: Chronic Cp infection is not more common in women whose pregnancy is complicated with PE as compared to pregnant women without PE. Therefore, no association between Cp infection and PE can be established.