Placental specific mRNA in the maternal circulation are globally dysregulated in pregnancies complicated by fetal growth restriction.

CONTEXT: Fetal growth restriction (FGR) is a leading cause of perinatal mortality, yet no reliable screening test exists. Placental specific mRNA in the maternal circulation may reflect changes in the placental transcriptome in FGR and could be a novel biomarker for FGR.

OBJECTIVE

The aim of the study was to identify placental specific RNA detectable in the maternal circulation and examine whether they are differentially expressed in severe preterm FGR.

DESIGN

In silico screening was used to identify placental specific RNAs. Their expression in cases of severe FGR vs controls was examined in both maternal blood and placenta by microarray, RT-PCR, and in situ hybridization.

RESULTS

Via in silico analysis, we identified 137 genes very highly expressed in the placenta relative to other tissues. Using microarray, we found that they were detectable in the maternal blood and were globally dysregulated with preterm FGR; 75 genes (55%) had a ≥1.5-fold differential expression compared to controls. Eight genes (ERVWE-1, PSG1, PLAC4, TAC3, PLAC3, CRH, CSH1, and KISS1) were validated by RT-PCR to be significantly increased in both maternal blood and placenta in a larger cohort of severe FGR compared to controls. In situ hybridization confirmed PAPPA2 and ERVWE-1 localized to the syncytiotrophoblast.

CONCLUSION

There is global differential expression of placental specific mRNA in the maternal blood in pregnancies complicated by severe preterm FGR. Placental specific mRNA in maternal blood may represent a new class of biomarkers for preterm FGR.