Background: The action of plasma from women affected by gestational hypertension (GH) on nitric oxide synthase (NOS) activity in cultured human umbilical vein endothelial cells (HUVECs) was evaluated in the present study, together with the effect on cytosolic calcium, on Na+, K+-ATPase activity and on membrane fluidity.
Methods: At 80% confluence, cultured HUVECs were incubated for 3 h at 37 degreesC with fresh culture medium (control samples) or with 20% (v/v) plasma (from five healthy non-pregnant women, five healthy pregnant women and five pregnant women affected by GH).
Results: After incubation with GH plasma, we observed a significant reduction in NOS activity, intracellular calcium concentrations and Na+, K+-ATPase activity.
Conclusions: The present work gives further support to the hypothesis that a circulating factor in gestational hypertension, possibly produced by the fetoplacental unit, causes dysfunction of the vascular endothelial cells and NO reduction, resulting in a loss of vascular refractoriness to vasoactive agents.