The study found that a protein called kisspeptin (KiSS-1) is higher in placentas from women with preeclampsia and that this higher level makes placental cells less able to invade, which may contribute to the disease.

The expression of KiSS-1, MMP-9 and MMP-2 mRNAs and proteins was studied in placentas of women with preeclampsia (PE, n=47) and women of normal pregnancy (NP; n=30). In addition, KiSS-1 mRNA expression as well as cell growth, proliferation and invasion were examined in JAR cells (human trophoblast cell line) transfected with pcDNA3-KiSS-1vector. Expression of KiSS-1 mRNA and protein was higher (p<0.05) in women with PE compared with that of NP women. In contrast, expression of MMP-9 and MMP-2 was lower (p<0.05) in PE than in NP women. KiSS-1 mRNA was detected in JAR cells successfully transfected with pcDNA3-KiSS-1 gene (JAR-K1, JAR-K2, JAR-K3). KiSS-1 mRNA was not detected in JAR cells transfected with pcDNA3 gene (JAR-P1, JAR-P2) and non-transfected JAR cells. No difference (p>0.05) was observed in cell growth among these three cell types. Invasion ability was significantly lower (p<0.01) in JAR-K1, JAR-K2 and JAR-K3 cells compared to JAR-P cells and non-transfected JAR cells. Overexpression of KiSS-1 and insufficient expression of MMP-9 and MMP-2 in placenta were demonstrated in women with PE. The data suggests that KiSS-1 gene plays an important role in inhibiting trophoblast invasion during placental development.