Circulating microRNA expression as predictor of preeclampsia and its severity

Preeclampsia (PE) is a pregnancy syndrome characterized by hypertension and proteinuria, and a leading cause of maternal and fetal morbidity and mortality, with poorly defined pathophysiological mechanisms remain. Circulating microRNAs (miRNAs) are small, noncoding RNA molecules, which negatively regulate gene expression, and considered as promising biomarkers for PE. The objective of the study was to evaluate circulating miRNA signatures in women with PE compared to healthy women, and in women sub-grouped per PE severity. This study assessed miRNA expression profile in the plasma of 15 women with PE (7 mild and 8 severe) compared to 7 women with uncomplicated pregnancies. Circulating miRNA was extracted from maternal plasma, and the differential expression of 84 miRNA species were determined using customized pathway-focused miRNA profiler kits. A set of 7 miRNAs that were differentially expressed in PE patients and in mild vs. severe PE cases subgroups. These included miR-215, miR-155, miR-650, miR-210, miR-21 which were upregulated, and miR-18a, miR-19b1 were downregulated in women with PE compared to control women, and between women with severe PE compared to mild PE. In addition, four novel miRNAs comprising miR-518b and miR-29a which were upregulated, and miR-144, miR-15b which were downregulated in severe PE compared to mild PE. This study for the first time presents the differential expression profile of circulating miRNAs according to the severity of the disease. The results confirm the contribution of miRNA to PE pathogenesis, as well as being predictors of the severity of PE.