Absolute and Relative Quantification of Placenta-Specific MicroRNAs in Maternal Circulation with Placental Insufficiency-Related Complications

Placental insufficiency related complications are one of the leading causes of maternal and perinatal morbidity and mortality. This study investigated the quantification of placenta-specific microRNAs (miRNAs) in the maternal circulation during gestation in a cohort of women with normally progressing pregnancies, the differentiation between placental insufficiency related complications and normally progressing pregnancies, and the differentiation between placental insufficiency and normally progressing pregnancies during the early stages of gestation. Both absolute and relative quantification of placenta-specific miRNAs (ie, miR-516-5p, miR-517*, miR-518b, miR-520a*, miR-520h, miR-525, and miR-526a) was determined in 50 women with normally progressing pregnancies, 32 with complicated pregnancies [21 with preeclampsia with or without intrauterine growth retardation (IUGR) and 11 with IUGR, and 7 women with pregnancies at various gestational stages who later developed preeclampsia and/or IUGR using real-time PCR and a comparative C-T method relative to normalization factor (ie, geometric mean of ubiquitous miR-16 and let-7d). Both quantification approaches revealed significant increases in extracellular placenta specific miRNA levels over time in women with normally progressing pregnancies; however, they were not able to differentiate between normally progressing and complicated pregnancies at the time of preeclampsia and/or IUGR onset. Nevertheless, significant elevation of extracellular miRNA levels was observed during early gestation (ie, within the 12th to 16th weeks) in pregnancies with later onset of preeclampsia and/or IUGR. Early gestation extracellular miRNA screening can differentiate between women with normally progressing pregnancies and those who may later develop placental insufficiency related complications. (J Mol Diagn 2012, 14:160-167; DOI. 10.1016/j.jmoldx.2011.11.003)