Introduction: Women with preeclampsia (PE) have elevated plasma levels of NT-proBNP. We hypothesized that the placenta may be a source to these elevated levels.
Objectives: Our objectives were to study the plasma levels of NT-proBNP and the protein and mRNA expression of placental BNP in women with early and late onset PE and controls.
Methods: Plasma levels of NT-proBNP were measured in women with early (n=18) and late (n=20) onset PE, in two groups of healthy pregnant women in gestational week 24-32 (n=22) and 36-42 (n=14), and in non-pregnant women (n=20). Placental BNP protein and mRNA was studied with immunohistochemistry and qPCR. Placental release of NT-proBNP was studied with tissue culturing.
Results: Women with early (365 (14-9815) pg/ml) and late (176 (33-2547) pg/ml) onset PE had higher levels of NT-proBNP in plasma than their respective controls (p<0.001). A tendency towards higher plasma levels in early compared to late onset PE was observed (p=0.057). 20 out of 25 placental tissue samples had proBNP mRNA, no differences between the study groups were found. BNP protein was found in maternal spiral arteries and syncytiotrophoblasts. NT-proBNP peptide (6-7pg/ml) was present in medium used for placenta cultures.
Conclusions: Our results suggest that there may be a placental source of NT-proBNP. If this source is responsible for the elevated plasma levels of NT-proBNP in preeclamptic women and what role, if any, BNP/NT-proBNP play in PE pathophysiology remains to be elucidated.
Copyright © 2013. Published by Elsevier B.V.