Research Papers: Pathology:
A novel mechanism of angiotensin II-regulated placental vascular tone in the development of hypertension in preeclampsia
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Qinqin Gao1,*, Jiaqi Tang1,*, Na Li1,*, Xiuwen Zhou1,*, Yongmei Li1, Yanping Liu1, Jue Wu1, Yuxian Yang1, Ruixiu Shi1, Axin He1, Xiang Li1, Yingying Zhang1, Jie Chen1, Lubo Zhang2, Miao Sun1 and Zhice Xu1,2
1 Institute for Fetology, First Hospital of Soochow University, Suzhou, China
2 Center for Perinatal Biology, Loma Linda University, Loma Linda, California, USA
* These authors have contributed equally to this work
Zhice Xu, email:
Miao Sun, email:
Keywords: preeclampsia, placenta vascular, angiotensin II, Pathology Section
Received: December 12, 2016 Accepted: February 06, 2017 Published: February 16, 2017
The present study tested the hypothesis that angiotensin II plays a role in the regulation of placental vascular tone, which contributes to hypertension in preeclampsia. Functional and molecular assays were performed in large and micro placental and non-placental vessels from humans and animals. In human placental vessels, angiotensin II induced vasoconstrictions in 78.7% vessels in 155 tests, as referenced to KCl-induced contractions. In contrast, phenylephrine only produced contractions in 3.0% of 133 tests. In non-placental vessels, phenylephrine induced contractions in 76.0% of 67 tests, whereas angiotensin II failed to produce contractions in 75 tests. Similar results were obtained in animal placental and non-placental vessels. Compared with non-placental vessels, angiotensin II receptors and β-adrenoceptors were significantly increased in placental vessels. Compared to the vessels from normal pregnancy, angiotensin II-induced vasoconstrictions were significantly reduced in preeclamptic placentas, which was associated with a decrease in angiotensin II receptors. In addition, angiotensin II and angiotensin converting enzyme in the maternal-placenta circulation in preeclampsia were increased, whereas angiotensin I and angiotensin1-7 concentrations were unchanged. The study demonstrates a selective effect of angiotensin II in maintaining placental vessel tension, which may play an important role in development of hypertension in preeclampsia.
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