The reduction of circulating levels of IL-6 in pregnant women with preeclampsia by magnesium sulphate and nifedipine: In vitro evidence for potential mechanisms

•Levels of IL-6 which were initially increased in preeclampsia were reduced with MgSO4 and nifedipine treatment.•Levels of IL-6 were reduced in the conditioned medium from endothelial cells after phagocytosis of NTD.•MgSO4 decreased the ICAM-1 expression by endothelial cells in vitro.

IntroductionWomen with preeclampsia have elevated levels of inflammatory cytokines including IL-6. IL-6, which is known to activate endothelial cells and induce the production of necrotic trophoblastic debris from the placenta, may be important in the pathogenesis of preeclampsia. MgSO4 is a major therapy for the prevention of seizures in preeclampsia but it has been suggested to also have anti-inflammatory and vasodilatory properties.Methods22 pregnant women with preeclampsia and 68 normotensive controls were recruited and circulating IL-6 levels in these women were measured before MgSO4 and nifedipine treatment and after delivery. In addition, endothelial cells were treated with IL-6 or necrotic trophoblastic debris, generated from first trimester placental explants in the presence or absence of MgSO4in vitro, and cell-surface ICAM-1 was measured by ELISA. The levels of IL-6 in the culture medium were also measured. Furthermore nitric oxide synthetase activity in endothelial cells that had been treated with IL-6 was measured using l-NAME.ResultsCirculating levels of IL-6 in preeclampsia were reduced significantly following administration of MgSO4.In vitro, MgSO4 reversed the activation of endothelial cells induced by IL-6 but not by necrotic trophoblastic debris. The effect of MgSO4 in reversing the IL-6 induced activation of endothelial cells was not dependent upon nitric oxide synthetase. Treating placental explants with MgSO4 prevented the production of necrotic trophoblastic debris induced by IL-6.Discussionwe demonstrated that IL-6 levels drop following treatment with MgSO4 and nifedipine in vivo, and have identified several mechanisms by which this positive effect on IL-6 may occur in vitro.