Cytotoxic effects of soluble factor in preeclamptic sera on human trophoblasts

Evidence indicating abnormal biological behavior of trophoblasts has been seen in preeclamptic patients, but the mechanism is still unknown. We have previously shown that endothelial injury and neutrophil activation are-induced by certain factors in preeclamptic sera. We investigated the effect of sera from eight preeclamptic and 11 normal pregnant women on cellular proliferation and viability of trophoblasts. using H-3-thymidine incorporation and the trypan-blue dye exclusion test, respectively. Five of eight preeclamptic sera, but none of the normal pregnant sera, inhibited H-3-thymidine incorporation. The trypan-blue test revealed the sera reduced cellular viability. Gel permeation showed that the greatest growth-inhibitory activity corresponded to a molecular weight of 50 kDa. The serum-mixing test revealed this permeation and inhibitory preeclamptic sera suppressed the growth-promoting activity of normal pregnant sera in a dose-dependent manner. These results suggested the presence of certain factors in some preeclamptic sera that can affect cellular behavior of human trophoblasts.