[Relationship between neurokinin B and endothelin-1 and hypertensive disorders complicating pregnancy]

To investigate the relationship between neurokinin B (NKB), endothelin-1 (ET-1) and the pathogenesis of hypertensive disorder complicating pregnancy (HDCP).

22 HDCP, who received antenatal examination in the Department of Obstetrics and Gynecology of Union Hospital of Tongji Medical College in Huazhong University of Science and Technology from March to July in 2005, were selected for the study, including 12 gestational hypertension (gestational hypertension group) and 10 preeclampsia (preeclamptic group); 22 normal pregnant women in the same period were served as control. At different gestational weeks, maternal plasma levels of NKB and ET-1 in three groups were detected by enzyme-linked immunoassay technique, the expression and location of NKB in placenta were examined by immunohistochemical SP, and mRNA expressions of NKB and ET-1 in placenta were measured with RT-PCR method.

(1) At 10 - 14, 20 - 24, and 30 - 34 gestational weeks, the plasma levels of NKB and ET-1 in preeclamptic group were (35.6 +/- 5.2), (17.9 +/- 4.3), (39.5 +/- 4.3), (22.7 +/- 3.6), (47.1 +/- 3.3) and (27.5 +/- 3.5) microg/L, respectively; in the control group they were (22.9 +/- 3.3), (10.7 +/- 5.3), (30.2 +/- 3.4), (13.2 +/- 4.1), (34.6 +/- 4.3) and (16.6 +/- 4.8) microg/L, respectively. There was a significant difference between preeclamptic group and control group (P < 0.05), while there was no significant difference between gestational hypertension group and control group (P > 0.05). (2) Immunohistochemical staining for NKB protein was observed in all groups and was located in the villous syncytiotrophoblast and villous vascular endothelial cells as well as cytoplasm of stromal cells, mostly located in villous syncytiotrophoblast. The expressions of NKB in placenta of preeclamptic group (0.244 +/- 0.020) was significantly higher than that in control group (0.160 +/- 0.012), with a significant difference between the two groups (P < 0.05). However, there was no significant difference between gestational hypertension group (0.162 +/- 0.019) and control group (P > 0.05). (3) The transcription levels of the NKB mRNA (0.97 +/- 0.36) and ET-1 mRNA (0.90 +/- 0.36) in preeclamptic placentas were both significantly higher than those in control groups (0.78 +/- 0.54, 0.65 +/- 0.47, respectively), with a significant difference between the two groups (P < 0.05). But there was no significant difference between gestational hypertension group (0.80 +/- 0.40, 0.70 +/- 0.32, respectively) and control group (P > 0.05). (4) There was an evident positive correlation between plasma NKB and ET-1 levels in preeclampsia (r = 0.79, P < 0.05).

The significantly increased maternal plasma levels of NKB and ET-1 of patients with preeclampsia occur at early pregnancy (10 - 14 gestational weeks) before the onset of clinical symptoms. The change of maternal plasma levels of NKB and ET-1 is closely related to pathogenesis of HDCP.