The Study Of The Bidirectional Transfer Of Fetomaternal Plasma DNA In Preeclampsia

Objective To quantitative analyze the bidirectional transfer within fetomaternal plasma free DNA and study the relationship with preeclampsia. To analyze the effects of the bidirectional free DNA traffic in the development and prognosis of preeclampsia.Methods Using a polymerase chain reaction (PCR) assay to screen the informative mother-baby pairs of which the pregnant women who carrying male babies and delivered in hospital, including 60 examples of preeclampsia (study group) and normal pregnancy (control group) respectively. The transfer from mother-to-fetus or fetus-to-mother was determined by detecting the inserting/deletion polymorphisms involving the glutathione S-transferase M1 (GSTM1) and angiotensin-converting enzyme genes (ACE). The fetus-to-mother transfer of plasma DNA in pregnant women was studied using a fluorescence quantitative PCR (FQ-PCR) assay for sex-determining region Y (SRY) gene. For mother-to-fetus transfer, FQ-PCR assays for the insertion/deletion polymorphisms involving the GSTM1 and ACE genes were used. At the same time, radioimmunity assay was used to detect theβ-chorionic- gonadotropin hormone (β-HCG).Results①A total of 52 informative mother-baby pairs were selected in all of 120 pairs. In the study group, there were 12 pairs of the mild degree of preeclampsia and 15 pairs of the severe degree of preeclampsia. The control group included 25 informative mother-baby pairs.②In the plasma fraction, fetal DNA was detected in 100% of maternal plasma (52 of 52). Compared with the control group, the mean fractional concentration in the group of the mild and severe degree of preeclampsia appeared significantly difference among groups (P<0.001). The free fetal DNA concentration in preeclampsia was higher than which in the normal pregnancy.③Of the 27 informative mother-baby pairs, maternal DNA was detected only 10 pairs, including 4 pairs of mild degree of preeclampsia and 6 pairs of severe degree of preeclampsia. But 8 pairs in the control group were detected the maternal DNA. In the study group, the median fractional concentration was higher than the control group. The difference among groups was significance (P<0.05). The free maternal DNA concentration in preeclampsia was higher than which in the normal pregnancy.④In comparision with normal pregnancy, the concentration ofβ-HCG in preeclampsia was significantly higher (P<0.001).⑤Both the mother-to-fetus or fetus-to-mother transfer of plasma DNA had positive relationship withβ-HCG (P<0.01). But there appeared to be no relationship between the fetus-to-mother and mother-to-fetus transfer of plasma DNA (P>0.05).Conclusions①The concentration of the bidirectional transfer of feto-maternal plasma DNA in preeclampsia was higher than normal pregnancy. It might have the correlation with the increasing apoptosis of trophoblastic cells in placenta. So the increasing of free DNA might mean that the damage of placenta had relationship with preeclampsia, and resulted the increasing changes between fetus and mother at last.②The bidirectional transfer of feto-maternal free DNA have the relationship with preeclampsia. These results also raise the possibility that measure- ment of circulating DNA may prove useful as a marker for the diagnosis and/or monitoring of preeclampsia.③The concentration of the bidirectional transfer of feto-maternal plasma DNA had relationship with the concentration ofβ-HCG. Both of them could be used as the index of prediction and /or monitoring of preeclampsia. It suggested that preeclampsia was associated with metabolism disturbances of circulating DNA.