Endoplasmic reticulum stress is induced in the human placenta during labour.

Placental endoplasmic reticulum (ER) stress has been postulated in the pathophysiology of pre-eclampsia (PE) and intrauterine growth restriction (IUGR), but its activation remains elusive. Oxidative stress induced by ischaemia/hypoxia-reoxygenation activates ER stress in vitro. Here, we explored whether exposure to labour represents an in vivo model for the study of acute placental ER stress. ER stress markers, GRP78, P-eIF2α and XBP-1, were significantly higher in laboured placentas than in Caesarean-delivered controls localised mainly in the syncytiotrophoblast. The similarities to changes observed in PE/IUGR placentas suggest exposure to labour can be used to investigate induction of ER stress in pathological placentas.This study was funded by the Wellcome Trust (Grant No. 084804/2/08/Z) in UK and Ter Meulen Fund, Royal Netherlands Academy of Arts and Sciences in Netherlands.This is the final published version. It originally appeared online at http://www.sciencedirect.com/science/article/pii/S0143400414008340#