Induction of heme oxygenase-1 attenuates sFlt-1-induced hypertension in pregnant rats

Preeclampsia (PE) is one of the leading causes of fetal and maternal morbidity, affecting 5–10% of all pregnancies, and lacks an effective treatment. The exact etiology of the disorder is unclear, but placental ischemia has been shown to be a central causative agent. In response to placental ischemia, the antiangiogenic protein fms-like tyrosine kinase-1 (sFlt-1), a VEGF antagonist, and reactive oxygen species are secreted, leading to the maternal syndrome. One promising therapeutic approach to treat PE is through manipulation of the heme oxygenase-1 (HO-1) protein. It has been previously reported that HO-1 and carbon monoxide downregulate sFlt-1 production in vitro, and we have recently shown that HO-1 induction significantly attenuates placental ischemia-induced hypertension, partially through normalization of the sFlt-1-to-VEGF ratio in the placenta. The purpose of this study was to determine whether HO-1 induction would have beneficial effects independently of sFlt-1 suppression. To that end, pregnant...