Correlation of Amniotic Fluid Index and Placental Aquaporin 1 Levels in Terms of Preeclampsia

Abstract

Background: Aquaporin 1 (AQP1) plays an important role in regulation of maternal-fetal fluid exchange and amniotic fluid volume. This present study aimed to determine the relationship between amniotic fluid index and placental AQP1 levels in terms of preeclampsia, as well as to reveal possible pathophysiological changes of AQP1 expression under preeclamptic conditions. Methods: Placenta tissues and medical records information were obtained from 389 preeclamptic and 447 uncomplicated pregnancies. Placental AQP1 levels were analyzed by molecular biological methods, DNA methylation in AQP1 gene promotor was determined by targeted bisulfite sequencing assay. Findings: Preeclamptic pregnancy had a greater frequency of oligohydramnios, and higher placental AQP1 levels. There was a significantly inverse correlation between amniotic fluid index and AQP1 levels in preeclamptic placenta. Additionally, the increased AQP1 was correlated with a decreased DNA methylation within the gene promoter. Interpretation:This study was the first description that a greater frequency of oligohydramnios in preeclampsia was strongly associated with reprogrammed AQP1 expression via a DNA methylation-mediated epigenetic mechanism. This study indicated an important role of AQP1-mediated maternal-fetal fluid balance and provided a potential direction for the identification of therapeutic targets for the treatment of abnormalities in preeclamptic amniotic fluid volume. Funding: This study was supported partly by Ministry of Science and Technology of China (2019YFA0802600), National Nature & Science Foundation of China (81873841, 81741024, and 81401244), “333 Project”, “Six one project (LGY2018076)”, “Shuang Chuang Tuan Dui” and Key Discipline “Fetal medicine” of Jiangsu Province, and the Suzhou city “Wei Sheng Ren Cai (GSWS2019029)” program. Declaration of Interest: None to declare. Ethical Approval: First Hospital of Soochow University, Suzhou, China. #302 (05/11/2015).