Expression changes of proteins associated with the development of preeclampsia in maternal plasma: A case‐control study

Defective deep placentation, involving abnormal transformation of the spiral arteries in the junctional zone of the myometrium, is known to cause significant obstetric complications, such as preeclampsia (PE), fetal growth restriction, and placental infarction leading to fetal death. Serological biomarkers to predict and diagnose PE would help antenatal care and reduce obstetric complications. To discover candidate PE biomarkers, we first performed global proteomic profiling of three pairs of plasma samples obtained from pregnant women in the early second trimester, who subsequently developed PE, and controls to identify candidate proteins that were abundant in the patients. We further evaluated the changes in the expression of PE‐representing proteins in stored plasma samples of a cohort that subsequently developed PE and their matched controls by MRM‐MS analysis. We identified that both complement C1s subcomponent (C1S) and protein AMBP were elevated in the plasma samples of the PE cohort before the manifestation of clinical disease. We propose that these proteins may be involved in the remodeling process of the spiral arteries even before PE manifestation. These proteins can serve as potential plasma biomarkers to predict the pregnant women having an increased risk of developing PE.