[Relationship of S100B protein expression and the pathogenesis of early-onset and late-onset preeclampsia].

OBJECTIVE: To investigate the relationship of S100B protein expression and the pathogenesis of early-onset and late-onset preeclampsia. METHODS: Sixty patients with preeclampsia who received caesarean section at Qingdao Municipal Hospital from October 2010 to September 2011 were enrolled in this study. Thirty cases were early-onset preeclampsia (referred as early-onset preeclampsia group, < 34 weeks), and the other 30 cases were late-onset preeclampsia (referred as late-onset preeclampsia group, ≥ 34 weeks). Thirty women who received caesarean section because of pelvic structural deformities, breech presentation, macrosomia and social factors were included as the control group. The expression of S100B mRNA in the placenta was detected by reverse transcription (RT)-PCR. The expression of S100B protein in the placenta was detected by immunohistochemistry. RESULTS: (1) S100B mRNA was expressed in the trophoblasts of preeclampsia and control groups. The expression of S100B mRNA in early-onset preeclampsia group (0.73 ± 0.11) was significantly higher than the control group (0.58 ± 0.08) and late-onset preeclampsia group (0.64 ± 0.10, P < 0.05). There was no significant difference between late-onset preeclampsia group and the control group (P > 0.05). (2) S100B protein was expressed in the plasma membrane and cytoplasm of the trophoblasts, correlated positively with the brownish yellow and brown particles inside the cells. It was expressed in all the three groups. Immunohistochemistry revealed that the expression of S100B protein in the placenta of early-onset preeclampsia group was 100% (30/30), significantly higher than those of late-onset preeclampsia group and the control group, in which the positive rate were 70% (21/30) and 63% (19/30) respectively (P < 0.05). There was no difference between late-onset preeclampsia group and the control group (P > 0.05). CONCLUSION: Early-onset and late-onset preeclampsia may have different etiology and pathogenesis. S100B may be a factor in the pathogenesis of early-onset preeclampsia.