Expression And Significance Of IGF-II And KiSS-1 In The Placenta Of Women With Preeclampsia

Background: Preeclampsia (PE) belongs to hypertensive disorder complicating pregnancy (HDCP) and the pathogenesis of preeclampsia is still unknown. Its etiology is always the hot issue of the research in the obstetric field. Extravillous trophoblasts of normal placenta deeply invade the decidua, the inner one-third of the myometrium (interstitial invasion) and the maternal spiral arteries (endovascular invasion), leading to morphological and functional changes known as"vascular remoulding". PE is associated with abnormally shallow cytotrophoblast invasion. Its vascular remoulding in the spiral arteties is confined to the decidual portion. Placental bed's spiral arteries escape entirely from endovascular trophoblast invasion. This doesn't cause an increase in the luminal width of the spiral arteries, which results in a deficient blood and oxygen supply to the placenta. Insulin-like growth factor-II (IGF-II) and KiSS-1 are expressed in trophoblasts of placenta. IGF-II and KiSS-1, which is related to cytotrophoblast invasion, may be involved in the pathogenesis of PE.Objectives: The study is aimed to evaluate expression and significance of IGF-II and KiSS-1 in placenta of pregnant women with PE. Methods:1. The microstructural changes in placentas from 25 cases of normal pregnant women and 40cases of pregnant women with PE were detected through microscopic examination of HE stained slices.2. The expression of IGF-II and KiSS-1 protein were detected by immunohistochemical S-P method in placentas from 25 cases of normal pregnant women and 40cases of pregnant women with PE.3. Forty women with PE, which within fifteen mild PE, twenty-five severe PE were enrolled in this study. Twenty-five healthy pregnancies were recruited as the control group. Placenta tissues were obtained from the PE and the healthy control groups for analysis of the IGF-II mRNA and KiSS-1 mRNA expression by using the quantitative reverse transcriptase-polymerase chain reaction (RT-PCR).Results:1. Under the microscopic examination, swelling villi, findings of fibrinoid necrosis of villi, hyperplasia of syncytial knots and cytotrophoblast, the smaller intervessel space, and deficiency of vasculo-syncytial membrane were detected easily in the placenta of preeclampsia. However, these microstructural changes were fewer in the normal placenta.2. The distribution of IGF-II and KiSS-1 protein in placenta of PE group was similar to that of normal group. IGF-II protein was found in the plasma and matrices of villous cytotrophoblast, villous syncytiotrophoblast and amnio-chorion; While KiSS-1 protein was found in the plasma or on the membrane of villous syncytiotrophoblast and villous stroma. The quantity of IGF-II protein in mild and serious group of PE was significantly lower than that in control group (P<0.05 and P<0.01, respectively).The expression of IGF- II protein decreased as the PE progressed. The quantity of KiSS-1 protein in mild and serious group of PE was significantly higher than that in control group (P<0.05 and P<0.01, respectively). The expression of KiSS-1 protein increased as the PE progressed. 3. Compared with normal group, the expression level of IGF-II mRNA in mild PE group and severe PE group were significantly lower (P<0.05); While the expression level of KiSS-1 mRNA in severe PE group were significantly higher than that of the normal group and mild PE group(P<0.05).Conclusion:1. The histologic abnormalities of placentas from women with PE are the adaptation response of villous trophoblast to ischemia and hypoxic conditions.2. Compared with normal group, the expression of IGF-II protein and IGF-II mRNA decreased as the PE progressed, which indicates that decreased IGF-II expression may be related to the pathogenesis of PE.3. Compared with normal group, the expression of KiSS-1 protein and KiSS-1mRNA increased as the PE progressed, which suggests that increased KiSS-1 expression may be related to the pathogenesis of PE.4. IGF-II and KiSS-1 are expressed in trophoblasts of placenta. IGF-II and KiSS-1, which are related to cytotrophoblast invasion, may be involved in the pathogenesis of PE.