Trophoblast Apoptosis in Placentas from Pregnancies Complicated by Preeclampsia

Aims: To assess trophoblast apoptosis separately in the cytotrophoblast, syncytiotrophoblast, total villous trophoblast, syncytial knots and syncytial knot formation, and to investigate the expression of apoptotic factors Fas ligand (FasL), Bcl-2 and proliferation marker Ki-67 in the trophoblast of placentas from preeclamptic patients. Methods: The study included placental samples from 25 preeclamptic and 25 normal pregnancies. For the detection of apoptosis and proliferation, antibody M30 and antibody against Ki-67 antigen were used. Expression of FasL and Bcl-2 was assessed using semi-quantitative HSCORE method. Syncytial knots were expressed as the number of syncytial knots per individual villus and as the total number of syncytial knots in each placental sample. Results: Trophoblast apoptosis, number of syncytial knots per individual villus and the total number of syncytial knots in each placental sample were significantly higher in preeclamptic placentas than in control group placentas. FasL expression was significantly less, and Bcl-2 expression significantly greater in the villus trophoblast among the study subjects compared with controls. There was no difference in the trophoblast proliferation between groups. Conclusion: Our findings might suggest that increased apoptosis and syncytial knot formation combined with reduced FasL expression could be involved in pathophysiological mechanisms of preeclampsia. Copyright (C) 2011 S. Karger AG, Basel