MicroRNAs (
miRNAs) are short non-coding RNAs that regulate gene expression at the post-transcriptional level. While mostly intracellular, a portion of cellular
miRNAs is released to the circulation and their level in the plasma is altered in certain pathological conditions such as
cancer, and also during pregnancy. We examined the circulating levels of a set of trophoblastic
miRNAs, which we recently found to be regulated by
hypoxia, in the plasma of pregnant women with
fetal growth restriction (FGR). Pregnancy was associated with increased plasma levels of several placenta-specific
miRNAs, compared to non-pregnant controls. Among pregnant women, the overall levels of
miRNA species that we analyzed were increased by 1.84-fold (p < or = 0.01) in plasma of women with pregnancies complicated by FGR, but decreased in FGR placentas by 24% (p < or = 0.01) compared to values from uncomplicated pregnancies. Together, our results show that plasma concentration of
miRNAs is regulated in pregnancy, and that FGR is associated with increased circulating
miRNA levels, highlighting the need to explore plasma
miRNAs as potential
biomarkers for
placental diseases.