Patients and study samples
Eighty-five placentas were obtained from women who underwent cesarean delivery at the General Hospital of Ningxia Medical
University between 2017 and 2021. PE was defined as a systolic blood
pressure ≥140 mmHg and a diastolic blood pressure ≥90 mmHg in two
consecutive measurements taken at least 6 h apart, along with
proteinuria (≥0.3 g/24 h) after 20 weeks of gestation. Placentas from
non-PE pregnancy volunteers (pregnant controls (PCs), n=40), with no
medical history or medication usage, served as controls.Placentas in the PE pregnancy group (n=45) were obtained from
pregnant patients who delivered with early-onset PE (<34 weeks
gestation). The exclusion criteria included multiple gestations, fetal
congenital malformations/chromosomal abnormalities, recent infection,
antiphospholipid antibodies, trauma, drug/alcohol abuse during
pregnancy, hypertension that had been discovered before 20 weeks,
thrombophilia with a history of PE, receiving
anticoagulant/antiaggregation therapy, smoking, and incomplete
data from pregnant women’s obstetric examinations. Placentas were
collected from the central part within 10 min of cesarean delivery,
avoiding macroscopic areas of infarction and calcification. After
rinsing briefly in saline, the samples were frozen at -80°C or fixed in
polyformaldehyde until further analyses. All experiments were conducted
following the protocol approved by the Clinical Research Ethics
Committee of Ningxia Medical University (NO. 2017-083), and informed
consent was obtained from all patients.