Secretion of prostaglandins and endothelin-1 by decidual endothelial cells from normal and preeclamptic pregnancies: comparison with human umbilical vein endothelial cells

In vitro migration of cytotrophoblasts through a decidual endothelial cell monolayer: the role of matrix metalloproteinases

Deficient trophoblast invasion is a major feature of pre-eclampsia. In vitro studies suggest that in normal pregnancy, maternal cells may play a role in controlling trophoblast invasion, although the exact nature of the regulatory interactions between these cells is not fully understood. To examine the effect of maternal-placental cell interactions on matrix metalloproteinase (MMP) secretion and endovascular cytotrophoblast migration in normal pregnancy and in pre-eclampsia, we performed co-culture experiments using cytotrophoblasts from normal pregnancies, together with decidual endothelial cells from both normal and preeclamptic pregnancies. Cells were incubated on semi-permeable membranes with or without phorbol 12-myristate 13-acetate (PMA). Results showed that third trimester cytotrophoblasts are migratory under basal conditions and display a different MMP profile from decidual endothelial cells. Co-culture did not damage either cell type and resulted in reduced latent MMP-9 secretion and reduced cytotrophoblast migration. Although PMA upregulated MMPs in decidual endothelial cells, it had no effect on cytotrophoblast MMP secretion. PMA, however, reduced cytotrophoblast migration. Pre-eclamptic decidual endothelial cells showed reduced MMP-1 secretion, but overall were not different in co-culture from normal endothelial cells. This study demonstrates the effectiveness of a bilayer co-culture model to study maternal-foetal cell interactions and provides evidence that maternal cells may contribute to the control of endovascular cytotrophoblast invasion.

Modulation of prostacyclin and thromboxane secretion by cytotrophoblasts from normal and pre-eclamptic human pregnancies

We and others have previously observed an imbalance in cytotrophoblast secretion of the vasoactive prostanoids prostacyclin and thromboxane A(2) in pre-eclampsia. To examine the effects of potential modulators of this imbalance, cytotrophoblasts isolated from normal and pre-eclamptic pregnancies were incubated in the presence of lipopolysaccharide, the calcium ionophore A23187, tumour necrosis factor alpha, or interleukin 1beta, with or without the cyclo-oxygenase inhibitor, indomethacin. Further incubations included the drugs tranylcypromine, a prostacyclin synthetase inhibitor (0.1, 10 microM ), or the thromboxane synthetase inhibitor, pirmagrel (0.001, 1 microM ). Results showed that cytotrophoblasts from pre-eclamptic pregnancies had increased thromboxane production and significant stimulation of prostacyclin production by lipopolysaccharide and calcium ionophore. Lipopolysaccharide stimulated thromboxane production in normal cytotrophoblasts, while indomethacin almost completely inhibited production of both prostanoids. Tranylcypromine mildly inhibited prostacyclin production in normal cytotrophoblasts only, whereas pirmagrel strongly inhibited thromboxane production in a dose-related manner, with reciprocal increase in prostacyclin production occurring in cytotrophoblasts from pre-eclamptic pregnancies. This study confirmed that cytotrophoblasts from pre-eclamptic women had increased thromboxane production and showed that pirmagrel, at the relatively low dose of 0.001 microM, was able to normalize the imbalance of thromboxane and prostacylin production and may therefore warrant further investigation as a treatment for pre-eclampsia.

In vitro human decidual endothelial cell thromboxane secretion in preeclampsia is not abnormal

OBJECTIVES

The aims of this study were to describe levels of thromboxane secretion by decidual endothelial cells from normal pregnancies and to determine whether decidual endothelial cell secretion of thromboxane, implicated in the causation of the hypertension and vasoconstriction of preeclampsia, is increased in this disorder.

METHODS

We measured thromboxane generation by cultured decidual endothelial cells from 13 normal pregnancies (NDEC) and 13 pregnancies complicated by preeclampsia (PEDEC), compared with a control population of 6 normal human umbilical vein endothelial cells (HUVEC). Responses to stimulation by bacterial lipopolysaccharide (LPS), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1 beta (IL-1 beta) were examined.

MAIN OUTCOME MEASURES

Thromboxane B2 levels in supernatants of cultured endothelial cells.

RESULTS

The level of secretion over 24 h in culture by NDEC [14 (7-26) pg/10(6) cells] was approximately 25% that of HUVEC [63 (49-70) pg/10(6) cells]. Levels achieved in response to all stimuli examined were consistently lower in NDEC than in HUVEC (p < 0.01). Proportional stimulation by LPS and TNF-alpha was comparable in HUVEC and NDEC, whereas NDEC displayed a greater increase (25-fold) than HUVEC (10-fold) in response to IL-1 beta (p < 0.01). There were no significant differences between decidual endothelial cells from normotensive and preeclamptic women in basal secretion of thromboxane or in responses to the stimuli examined.

CONCLUSIONS

In vitro thromboxane secretion by decidual endothelial cells is lower than that of HUVEC, and responsiveness to specific stimuli may be quantitatively different. These findings emphasize the importance of examining endothelial cells from the involved maternal vascular bed if intrauterine vascular pathophysiological events are to be clarified. No significant differences were noted in decidual endothelial cell thromboxane secretion between normal and preeclamptic subjects.

Imbalance between the endothelial cell-derived contracting factors prostacyclin and angiotensin II and nitric oxide/cyclic GMP in human primary varicosis

1. The role of the endothelium in the vasomotor control of human veins in the lower extremity is little understood. We tested the hypothesis that the production of relaxing and contracting factors is altered in endothelial cells from varicose saphenous veins which may predispose to the decreased vessel tone observed in primary varicosis. 2. We determined the intracellular accumulation of guanosine 3':5'-cyclic monophosphate cyclic GMP; a measure of nitric oxide production and the release of endothelin and prostacyclin (measured as its stable metabolite 6-keto-prostaglandin F1alpha) from cultured cells derived from the long saphenous veins of patients with primary varicosis (Varicose saphena group, n = 27) or from patients undergoing coronary artery bypass surgery (Healthy saphena group, n = 22). In addition, levels of endothelin, angiotensin II, bradykinin, cyclic GMP and cyclic AMP in plasma from patients with primary varicosis and healthy volunteers (n = 8-11 in each group) were determined. 3. Although basal cyclic GMP levels were similar, more cyclic GMP accumulated in response to histamine (1-100 micromol l[-1]) in cells from varicose saphenous veins (0.75 +/- 0.1 pmol per well) than in cells from veins without varicosis (0.27 +/- 0.05 pmol per well). Furthermore, the relaxant potency of nitroprusside (1 nmol l(-1) - 300 micromol l[-1]) in vitro was higher for varicose veins (mean EC50 = 5.9 micromol l(-1); n = 8) than healthy veins (mean EC50 = 20.0 micromol l(-1); n = 7). 4. The production of prostacyclin was significantly less in cells from varicose than healthy saphenous veins (66 +/- 8.7 and 121 +/- 20.1 nmol g(-1) protein), but the production of endothelin was similar in both groups. Prostacyclin (3 nmol l(-1) 30 micromol l[-1]) consistently contracted rings of varicose saphenous vein in vitro with a mean EC50 value of 10-20 micromol l(-1) (n = 7); the maximum tension generated was approximately 50% of that of a completely depolarizing solution of K+ (120 mmol l[-1]). 5. In plasma from patients with varicose veins, levels of cyclic GMP were higher than in healthy controls (9.2 +/- 0.03 and 7.2 +/- 0.02 nmol l[-1]), levels of angiotensin II were lower (81 +/- 11.5 and 147 +/- 21.7 pmol l[-1]), and levels of endothelin, cyclic AMP, and bradykinin were not different. 6. It is concluded that endothelial cells from diseased saphenous veins secrete less constrictor mediators than cells from healthy veins and that in diseased veins the nitric oxide/cyclic GMP system is up-regulated which may shift the balance of vasoactive factors towards vasodilatation and contribute to the development of primary varicosis.