2.1. Patients and Sample Acquisition

From January 2021 to June 2021, 40 patients with preeclampsia and 34 patients with normal pregnancies (controls) who underwent a cesarean section in the Obstetrics Department of the International Peace Maternity and Child Health Hospital were enrolled in this study. Patients were excluded if they had gestational diabetes or other pregnancy complications, renal disease, multiple pregnancies, thyroid dysfunction, or chronic hypertension. We collected placental tissue samples from all enrolled individuals. The placental tissue was taken from the area near the umbilical cord insertion site and collected rapidly within 30 minutes after cesarean section. These tissue samples were cut into small pieces using sterile scissors, washed with sterile PBS. A portion was snap-frozen in liquid nitrogen and then stored in RNAlater reagent (Thermo Fisher Scientific, USA) at −80°C for RNA extraction and western blotting, and a portion was fixed with formalin and embedded in paraffin for immunohistochemical staining. In this experiment, 5 preeclampsia and 5 normal placental tissues were used for high-throughput sequencing, and the remaining 35 disease groups and 29 control groups were used as the validation of the cell experiment in vitro. The flowchart in Figure 1 illustrates the whole process of this study. This study was approved by the ethics committee of the International Peace Maternal and Child Health Hospital (Approval No. GKLW 2021-23) and has been registered in the Chinese clinical trial registry (http://www.clinicaltrials.gov; registration number: ChiCTR1900027479), and all patients provided written informed consent.

Flowchart of study design.