Placental transcriptome analysis of hypertensive pregnancies identifies distinct gene expression profiles of preeclampsia superimposed on chronic hypertension

The pathogenesis of preeclampsia superimposed on chronic hypertension is poorly understood relative to preeclampsia occurring in pregnant people without chronic hypertension. Placental transcriptomes in pregnancies complicated by de novo preeclampsia and superimposed preeclampsia have not been previously compared. Overall design: The goal of this study is to investigate the transcriptomes of placentas from different types of hypertensive pregnancies. We identified pregnant people in the University of Michigan Biorepository for Understanding Maternal and Pediatric Health with hypertensive disorders affecting singleton, euploid gestations (N=36) along with non-hypertensive control subjects (N=12). Subjects were grouped as: (1) normotensive (N=12), (2) chronic hypertensive (N=13), (3) preterm preeclampsia with severe features (N=5), (4) term preeclampsia with severe features (N=11), (5) preterm superimposed preeclampsia (N=3), or (6) term superimposed preeclampsia (N=4). Bulk RNA sequencing of paraffin-embedded placental tissue was performed.