Apoptosis, proliferation and Fas ligand expression in placental trophoblast from pregnancies complicated by HELLP syndrome or pre‐eclampsia

Objective. To investigate apoptosis, proliferation and Fas ligand expression of placental trophoblast in the hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome and in pre‐eclampsia (PE), and to compare this with normal pregnancies. Design. Prospective study. Setting. University hospital in Croatia. Sample. Placentae from women with HELLP syndrome ( n =10), PE ( n =10) and normal pregnancies ( n =10). Methods. The HELLP syndrome was diagnosed with platelets <100×10 9 /L, aspartate aminotransferase (AST) and alanine transaminase (ALT) >70U/L and lactic acid dehydrogenase (LDH) > 600U/L. Pre‐eclampsia was diagnosed at blood pressure >140/90mmHg, with proteinuria >300mg/L/24hours. For detection of apoptosis and proliferation in villous trophoblast, antibodies M30 and Ki‐67 were used. Expression of Fas ligand was assessed using immunohistochemistry and the semiquantitative HSCORE method. Main Outcome Measures. Apoptosis, proliferation and Fas ligand expression in villous trophoblast. Results. Apoptosis, proliferation and Fas ligand expression were higher in villous trophoblast in HELLP syndrome than in the PE group ( p =0.015, p =0.018 and p =0.002, respectively) and the control group ( p =0.000, p =0.012 and p =0.049, respectively). Placentae from the PE group had higher levels of apoptosis ( p =0.019), lower Fas ligand expression ( p =0.029) and no difference in proliferation ( p =0.887) compared with the control group. Conclusions. There is an increase in apoptosis, proliferation and Fas ligand expression in placentae from women with HELLP syndrome compared with placentae from PE and normal pregnancies. Our findings indicate the possibility of differential mechanisms behind HELLP syndrome and PE.