Sera from preeclamptic women increase the content of triglycerides and reduce the release of prostacyclin in cultured endothelial cells

Pathophysiological Insight into Fatty Acid-Binding Protein-4: Multifaced Roles in Reproduction, Pregnancy, and Offspring Health

Fatty acid-binding protein-4 (FABP4), commonly known as adipocyte-fatty acid-binding protein (A-FABP), is a pleiotropic adipokine that broadly affects immunity and metabolism. It has been increasingly recognized that FABP4 dysfunction is associated with various metabolic syndromes, including obesity, diabetes, cardiovascular diseases, and metabolic inflammation. However, its explicit roles within the context of women's reproduction and pregnancy remain to be investigated. In this review, we collate recent studies probing the influence of FABP4 on female reproduction, pregnancy, and even fetal health. Elevated circulating FABP4 levels have been found to correlate with impaired reproductive function in women, such as polycystic ovary syndrome and endometriosis. Throughout pregnancy, FABP4 affects maternal-fetal interface homeostasis by affecting both glycolipid metabolism and immune tolerance, leading to adverse pregnancy outcomes, including miscarriage, gestational obesity, gestational diabetes, and preeclampsia. Moreover, maternal FABP4 levels exhibit a substantial linkage with the metabolic health of offspring. Herein, we discuss the emerging significance and potential application of FABP4 in reproduction and pregnancy health and delve into its underlying mechanism at molecular levels.

Preeclampsia with Intrauterine Growth Restriction Generates Morphological Changes in Endothelial Cells Associated with Mitochondrial Swelling-An In Vitro Study

Pregnancy complicated by preeclampsia (PE) and intrauterine growth restriction (IUGR) promotes endothelial cell (EC) dysfunction. Our in vitro study aimed to evaluate the endothelial cell morphology after acute and chronic exposition to medium supplemented with serum taken from healthy pregnant women and women with IUGR and IUGR with PE. In the same condition, ECs viability, proliferation, reactive oxygen species (ROS) production, and serum concentration of vascular endothelial growth factor (VEGF) were also measured. Pregnant women with IUGR and IUGR with PE-delivered babies with reduced body mass and were characterized in elevated blood pressure, urine protein loss, and reduced level of VEGF. The 24 hours of exposition did not exert any morphological changes in ECs, except the reduction in cell viability, but prolonged exposition resulted in significant morphological changes concerning mostly the swelling of mitochondria with accompanying ROS production, cell autophagy, reduced cell viability, and proliferation only in complicated pregnancies. In conclusion, the sera taken from women with IUGR and IUGR with PE show a detrimental effect on ECs, reducing their viability, proliferation, and generating oxidative stress due to dysfunctional mitochondria. This multidirectional effect might have an adverse impact on the cardiovascular system in women with IUGR and PE.

Endothelial dysfunction in pregnancy metabolic disorders

In recent years, the vascular endothelium has gained attention as a key player in the initiation and development of pregnancy disorders. Endothelium acts as an endocrine organ that preserves the homeostatic balance by responding to changes in metabolic status. However, in metabolic disorders, endothelial cells adopt a dysfunctional function, losing their normal responsiveness. During pregnancy, several metabolic changes occur, in which endothelial function decisively participates. Similarly, when pregnancy metabolic disorders occur, endothelial dysfunction plays a key role in pathogenesis. This review outlines the main findings regarding endothelial dysfunction in three main metabolic pathological conditions observed during pregnancy: gestational diabetes, hypertensive disorders, and obesity and hyperlipidemia. Organ, histological and cellular characteristics were thoroughly described. Also, we focused in discussing the underlying molecular mechanisms involved in the cellular signaling pathways that mediate responses in these pathological conditions.

Preeclampsia and HELLP syndrome, the role of the liver

Preeclampsia is a multisystemic disorder which accounts for the high prevalence of maternal and perinatal morbidity and mortality, especially in middle and low-income countries. Currently, the primary intervention is the urgent delivery of the fetus, hence it would be advantageous to identify those who are likely to develop preeclampsia and the maternal and fetal outcomes. However, an array of risk factors makes these challenging. This review explores the potentials of liver biomarkers in predicting the occurrence and outcome of preeclampsia, which could be beneficial in reducing the burden of the disease. Liver dysfunction in preeclampsia results in a severe condition, hence liver function tests are specific predictors of outcome.

Vascular adaptation in pregnancy and endothelial dysfunction in preeclampsia

Maternal vascular adaptation to pregnancy is critically important to expand the capacity for blood flow through the uteroplacental unit to meet the needs of the developing fetus. Failure of the maternal vasculature to properly adapt can result in hypertensive disorders of pregnancy such as preeclampsia (PE). Herein, we review the endocrinology of maternal adaptation to pregnancy and contrast this with that of PE. Our focus is specifically on those hormones that directly influence endothelial cell function and dysfunction, as endothelial cell dysfunction is a hallmark of PE. A variety of growth factors and cytokines are present in normal vascular adaptation to pregnancy. However, they have also been shown to be circulating at abnormal levels in PE pregnancies. Many of these factors promote endothelial dysfunction when present at abnormal levels by acutely inhibiting key Ca²⁺ signaling events and chronically promoting the breakdown of endothelial cell-cell contacts. Increasingly, our understanding of how the contributions of the placenta, immune cells, and the endothelium itself promote the endocrine milieu of PE is becoming clearer. We then describe in detail how the complex endocrine environment of PE affects endothelial cell function, why this has contributed to the difficulty in fully understanding and treating this disorder, and how a focus on signaling convergence points of many hormones may be a more successful treatment strategy.

Reduced Cellular Glutathione Reductase Activity and Increased Adhesion Molecule Expression in Endothelial Cells Cultured With Maternal Plasma From Women With Preeclampsia

OBJECTIVE

The purpose of the current study was to determine whether maternal circulating components could regulate oxidative status of glutathione redox cycle and adhesion molecule expression in endothelial cells (ECs).

METHODS

Maternal plasma was extracted from venous blood obtained from normal term pregnant women and from women with preeclampsia (PE). Normal and PE pregnancies were defined as American College of Obstetricians and Gynecologists criteria. Confluent ECs were incubated with EC growth medium (EGM) containing 20% plasma from women with normal (n = 8) and PE (n = 8) pregnancies for 4 hours. ECs incubated with EGM only were used as control. EC oxidative status was assessed by measuring cellular glutathione reductase (GR) and glutathione peroxidase (GPx) activities. Adhesion molecule expressions for intercellular adhesion molecule (ICAM), vascular cell adhesion molecule (VCAM), P-selectin, and E-selectin were determined by colorimetric assays detected on EC surface by UV spectrophotometer at OD 450 nm. Data are presented as mean +/- SE and analyzed by analysis of variance (ANOVA). A P value < .05 was set as statistically significant.

RESULTS

Cellular GR activity was reduced approximately 35% in ECs treated with normal plasma and 70% in ECs treated with PE plasma compared to that in untreated control cells: 0.072 +/- 0.014 (P < .05), 0.039 +/- 0.006 (P < .01), versus 0.117 +/- 0.010 U/mg cellular protein, respectively. In contrast, GPx activity was slightly increased in ECs treated with normal plasma and significantly increased in ECs treated with PE plasma compared to that in untreated control cells: 0.059 +/- 0.005, 0.075 +/- 0.012 (P < .05) versus 0.044 +/- 0.002 U/mg cellular protein, respectively. P-selectin, E-selectin, and VCAM expressions were elevated in cells treated with normal plasma but significantly increased in cells treated with PE plasma compared to those of untreated controls: P-selectin--0.18 +/- 0.03, 0.35 +/- 0.04 versus 0.04 +/- 0.01 OD 450 nm, P < .01; E--selectin-0.06 +/- 0.02, 0.10 +/- 0.02 (P < .05) versus 0.03 +/- 0.01 OD 450 nm; VCAM--0.12 +/- 0.02, 0.16 +/- 0.03 (P < .01) versus 0.08 +/- 0.02 OD 450 nm, respectively. There was no difference for ICAM expression in cells treated with normal or PE plasma compared to controls.

CONCLUSIONS

These data suggest that endothelial pro- and anti-oxidative status could be directly affected by circulating components during pregnancy. Reduced cellular GR activity and increased GPx activity accompany increased inflammatory reactions in ECs responding to circulating "toxic" factors in preeclampsia.

Acute Atherosis of the Uterine Spiral Arteries: Clinicopathologic Implications

Acute atherosis is unique vascular changes of the placenta associated with poor placentation. It is characterized by subendothelial lipid-filled foam cells, fibrinoid necrosis of the arterial wall, perivascular lymphocytic infiltration, and it is histologically similar to early-stage atherosclerosis. Acute atherosis is rare in normal pregnancies, but is frequently observed in non- transformed spiral arteries in abnormal pregnancies, such as preeclampsia, small for gestational age (SGA), fetal death, spontaneous preterm labor and preterm premature rupture of membranes. In preeclampsia, spiral arteries fail to develop physiologic transformation and retain thick walls and a narrow lumen. Failure of physiologic transformation of spiral arteries is believed to be the main cause of uteroplacental ischemia, which can lead to the production of anti-angiogenic factors and induce endothelial dysfunction and eventually predispose the pregnancy to preeclampsia. Acute atherosis is more frequently observed in the spiral arteries of the decidua of the placenta (parietalis or basalis) than in the decidual or myometrial segments of the placental bed. The presence and deeper location of acute atherosis is associated with poorer pregnancy outcomes, more severe disease, earlier onset of preeclampsia, and a greater frequency of SGA neonates in patients with preeclampsia. Moreover, the idea that the presence of acute atherosis in the placenta may increase the risk of future cardiovascular disease in women with a history of preeclampsia is of growing concern. Therefore, placental examination is crucial for retrospective investigation of pregnancy complications and outcomes, and accurate placental pathology based on universal diagnostic criteria in patients with abnormal pregnancies is essential for clinicopathologic correlation.

Plasma from preeclamptic women activates endothelial cells via monocyte activation in vitro

In this study we tested whether plasma from preeclamptic women contains factors that can activate endothelial cells in the presence of monocytes in vitro. Plasma from preeclamptic women (n=6), healthy pregnant women (n=6) and nonpregnant women (n=6) was incubated with mono-cultures and co-cultures of human umbilical vein endothelial cells (HUVEC) and monomac-6 monocytes. Reactive oxygen species (ROS) production and ICAM-1 expression were measured using flow cytometry. Whether scavenging of ROS by superoxide dismutase and catalase inhibited HUVEC ICAM-1 expression was also investigated. We found that in HUVEC co-cultured with monomac-6 cells but not in HUVEC cultured alone, ICAM-1 was upregulated after incubation with plasma from preeclamptic women but not plasma from non-pregnant women. Also in co-cultures, monomac-6 ICAM-1 was upregulated by plasma from preeclamptic women, while in both mono- and co-cultures monomac-6 ROS production was upregulated by plasma from pregnant and preeclamptic women, compared with plasma from non-pregnant women. Scavenging of ROS by superoxide dismutase and catalase resulted in a further upregulation of HUVEC ICAM-1 after incubation with plasma from preeclamptic women, compared with incubation without superoxide dismutase and catalase. These results show that endothelial cells in vitro are activated by plasma of preeclamptic women only if they are co-cultured with monocytes. This upregulation appeared not to be due to extracellular ROS production by monocytes or HUVEC, pointing to involvement of other mechanisms. Our data suggest that plasma of preeclamptic women activates monocytes, and that these monocytes subsequently activate endothelial cells.

A potential role for free fatty acids in the pathogenesis of preeclampsia

OBJECTIVE

Pregnant women with the vascular complication of preeclampsia show altered lipid metabolism characterized by elevated circulating triglycerides and nonesterified free fatty acids. We have compared the effect of maternal plasma from women with and without preeclampsia on cultured vascular endothelial cells and determined whether these plasma-induced changes were reproduced with free fatty acid solutions of palmitic, oleic and linoleic acid, representative of circulating levels reported in preeclampsia.

METHODS

Lipid accumulation was quantified by oil-red O staining, apoptosis by terminal dUTP nick-end labelling (TUNEL) and the measurement of mitochondrial redox capacity, and membrane potential recorded using MTT reduction and JC-1 accumulation for human umbilical vein endothelial cells (HUVECs) exposed to plasma and free fatty acids.

RESULTS

Lipid droplet accumulation was significantly increased in cultured HUVECs conditioned with maternal plasma from pregnancies with preeclampsia compared with normal uncomplicated controls. This increase was replicated following exposure to free fatty acids at the combined concentrations defined in preeclampsia. Plasma from these women also caused a significant decrease in mitochondrial dehydrogenase activity, a marked reduction in mitochondrial membrane potential and an increase in apoptosis compared with normal pregnancy. Again these effects were reproduced using free fatty acids in combination at the levels previously associated with preeclampsia.

CONCLUSION

These findings support the concept of a circulating pathogenic factor for preeclampsia and highlight the possibility that this factor is not a single compound but perhaps the combined elevation of the free fatty acids palmitic, oleic and linoleic acid in the maternal circulation.

Free fatty acid profiles in preeclampsia

Preeclampsia has many characteristics similar to the metabolic syndrome. One of these is aberrant lipid metabolism. We studied free fatty acid (FFA) profiles at baseline and after oral glucose load in 21 preeclamptic and 11 normotensive pregnant women. Insulin sensitivity was measured by intravenous glucose tolerance test. We found that serum total FFA concentrations at baseline were 67% higher in preeclamptic than in normotensive pregnancies (P=0.0002). The difference between the two groups was largest in the concentrations of oleic (75%), linoleic (129%) and arachidonic (315%) acids. Oral intake of glucose suppressed total FFA in preeclamptic women by 40% (95% CI 32.1-46.1%, P<0.0001) but only 24% in control women (95% CI 0.01-42.0%, P=0.045). Insulin sensitivity, which in preeclamptic women was 37% lower (P=0.009), was unrelated to total or any individual FFA concentration. We concluded that preeclamptic women have higher circulating FFA concentrations, which despite insulin resistance are suppressed by oral glucose loading.

Serum lecithin: cholesterol acyltransferase activity, HDL2 and HDL3 composition in hypertensive mothers and their small for gestational age newborns

The aim of this study was to determine serum lecithin:cholesterol acyltransferase (LCAT) activity in parallel with HDL2 and HDL3 amounts and composition in pregnancy induced hypertension (PIH) and chronic hypertensive (CH) mothers and in their small for gestational age (SGA) newborns. LCAT activity was assayed by conversion of [3H] cholesterol to labelled cholesteryl ester. HDL2 and HDL3 were separated by ultracentrifugation. At term, cholesterol values were similar in PIH, CH and controls. However, higher levels of triglycerides were observed in PIH and CH (+20% and +21%, respectively) as compared with normotensive control mothers (NC). HDL2 and HDL3-phospholipids, HDL2-cholesterol concentrations and LCAT activity were lower in PIH and CH mothers than in NC mothers. Similar changes were also observed in SGA newborns of PHI mothers and in SGA newborns of CH mothers when compared to appropriate for gestational age newborns of control mothers (AGA-NC). In addition, SGA newborns showed low HDL2 and HDL3 apoA-I contents. Maternal hypertension and foetal intrauterine growth retardation are associated with profound abnormalities in HDL metabolism, consistent with an atherogenic risk. SGA lipoprotein profiles appear to implicate later metabolic diseases.

First trimester sex hormone-binding globulin and subsequent development of preeclampsia or other adverse pregnancy outcomes

OBJECTIVE

To investigate whether first trimester maternal serum sex hormone-binding globulin (SHBG) concentrations are altered in women who subsequently develop preeclampsia or other pregnancy complications.

POPULATION

Women undergoing first trimester combined ultrasound and biochemical screening for chromosomal anomalies. We searched the database and identified 32 pregnancies resulting in miscarriage, 64 pregnancies with preexisting or gestational diabetes mellitus, 107 with fetal growth restriction, 103 with preeclampsia, 64 with pregnancy-induced hypertension, and 26 with spontaneous preterm delivery. We also selected 400 controls from among the population of pregnancies that had a delivery of a normal baby with no pregnancy complications.

METHODS

Maternal serum SHBG concentrations were measured retrospectively using a competitive chemiluminescent immunoassay. The levels between those with normal outcome and those resulting in adverse outcome were compared.

RESULTS

The median maternal serum SHBG concentration was not significantly different from controls, in those that subsequently developed preeclampsia (median MoM 1.05), non-proteinuric hypertension (median MoM 0.94) or preterm delivery (median MoM 1.15). The levels were significantly lower in those with diabetes (median MoM, 0.81 p=0.0005) and those pregnancies resulting in miscarriage (median MoM 0.80, p=0.008).

CONCLUSION

First trimester maternal serum SHBG concentrations are no different from controls in women who subsequently develop preeclampsia, pregnancy-induced hypertension, fetal growth restriction, or preterm delivery. Levels are reduced in those who subsequently miscarry or in those presenting with diabetes.

Lack of proinflammatory effects of free fatty acids on human umbilical cord vein endothelial cells and leukocytes

AIM

To determine whether the free fatty acids (FFAs), oleic, linoleic, and palmitic acid, found elevated before 20 weeks of pregnancy in those women who later develop preeclampsia, induced changes in expression of the vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), or E-selectin in cultured human umbilical cord vein endothelial cells (HUVEC), and integrin subunit CD11b, L-selectin or intracellular reactive oxygen species (ROS) in leukocytes.

METHODS

The VCAM-1, ICAM-1, and E-selectin expression were measured using ELISA in HUVEC after incubation with 100 micromol of either oleic, linoleic, or palmitic acid for 6 hr and 24 hr. The co-reactivity with lipopolysaccharide (LPS), the amount of VCAM-1 mRNA in the cells, and soluble VCAM-1 in the incubation medium were measured as well. Leukocyte adhesion molecules and ROS were measured after incubation with 750 microm of either of the FFAs in a whole blood model using flow cytometry.

RESULTS

No effects of the FFAs tested were found on the HUVEC or leukocyte adhesion molecule expression or intracellular ROS. The only exception to this was palmitic acid incubation, which significantly lowered the VCAM-1 expression in HUVEC after 24-hr incubation and also slowed the decay of VCAM-1 expressed after stimulation with LPS.

CONCLUSIONS

The lack of significant proinflammatory changes of the FFAs tested might indicate that the elevated plasma levels of FFAs seen in preeclampsia most probably are products of the preeclamptic process rather than a causative factor.

Avancées dans la physiopathologie de la pré-éclampsie : place de la réponse inflammatoire

Inflammatory response is a major component in physiopathology of preeclampsia and intra-uterine growth retardation. Endothelium is a main connection between placental ischemia and clinical manifestations during vascular pregnancy complications. In this review recent findings concerning inflammatory response and its links with endothelium are reported. Studies concerning isolated intra-uterine growth retardation confirm the hypothesis of a similar pathophysiology with an activation confined to utero-placental bed or at a lower level. Current information on oxidative stress, atherosclerosis, and apoptosis in vascular pregnancy complications are available in this review. These concepts offer innovative possibilities of treatment.

Lipid-soluble antioxidants and pregnancy: maternal serum levels of coenzyme Q10, alpha-tocopherol and gamma-tocopherol in preeclampsia and normal pregnancy

It has been hypothesized that in preeclampsia, the antioxidant-deficient state may facilitate increased attacks of free radicals, which may result in endothelial cell damage. The purpose of this study was to investigate the association of three lipid-soluble antioxidants, coenzyme Q10, alpha-tocopherol and gamma-tocopherol, with preeclampsia and normal pregnancy. Serum levels of all three antioxidants in 42 women with normal pregnancies, 25 with mild preeclampsia and 28 with severe preeclampsia were measured by high-pressure liquid chromatography. A significant decrease was observed in serum levels of coenzyme Q10 and alpha-tocopherol (p < 0.001 for each by the Kruskal-Wallis rank test) in women with preeclampsia compared to levels in normal pregnancy. gamma-Tocopherol levels were comparable among the different groups. Logistic regression analysis revealed significant association between grades of preeclampsia and both serum coenzyme Q10 and alpha-tocopherol levels (p = 0.000 and 0.030, respectively). Coenzyme Q10 and alpha-tocopherol are potent antioxidants, and the decreased levels of these two antioxidants in preeclampsia may alter the normal redox balance, thereby reducing the ability of antioxidant defenses to protect against free radical damage. This could be a factor in the endothelial cell damage observed in preeclampsia.

Eicosanoids in preeclampsia

Preeclampsia is characterized by an imbalance between two cyclooxygenase metabolites of arachidonic acid, thromboxane and prostacyclin, that favors thromboxane. Because of the biologic actions of these two eicosanoids, this imbalance might explain major clinical symptoms of preeclampsia, such as hypertension, platelet aggregation and reduced uteroplacental blood flow. In the maternal circulation, this imbalance is primarily manifested by decreased production of prostacyclin by endothelial cells. Platelet thromboxane synthesis is only increased in severe preeclampsia. In the placenta and in leukocytes, the imbalance is exacerbated by increased production of thromboxane coupled with decreased production of prostacyclin in both mild and severe preeclampsia. Longitudinal measurements of urinary metabolites of thromboxane and prostacyclin reveal that the thromboxane/prostacyclin imbalance predates the onset of clinical symptoms of preeclampsia. The imbalance between thromboxane and prostacyclin is most likely caused by oxidative stress, which is manifest in preeclampsia by increased lipid peroxidation and decreased antioxidant protection. Oxidative stress may drive this imbalance because lipid peroxides activate the cyclooxygenase enzyme to increase thromboxane synthesis, but at the same time they inhibit prostacyclin synthase to decrease prostacyclin synthesis. Low-dose aspirin therapy (50-150 mg/day) has been considered for the prevention of preeclampsia because it selectively inhibits thromboxane synthesis. Several studies reported dramatic decreases in the incidence of preeclampsia with low-dose aspirin therapy. However, two large multicenter studies reported only modest decreases, which dampened enthusiasm. The two large studies were "intent to treat" studies which included patients who were noncompliant and who discontinued the use of aspirin. In one of the studies for which compliance statistics were available only 53% of the aspirin group had a compliance rate greater than 75%, which raises a question as to whether the effectiveness of aspirin was being tested. Low-dose aspirin therapy should not yet be dismissed for the prevention of preeclampsia, but be reconsidered with emphasis on compliance using doses of aspirin in the range of 100-150 mg/day combined with antioxidants.

Does postprandial storage of triglycerides in endothelial cells contribute to the endothelial dysfunction associated with insulin resistance and fatty diets?

Insulin resistance syndrome is associated with endothelial dysfunction characterized by decreased nitric oxide bioactivity and subnormal endothelium-dependent vasodilation. Excessive exposure to free fatty acids (FFAs) is thought to mediate this dysfunction, at least in part, since free fatty acid overexposure, both in vivo and in vitro, decreases the capacity of endothelial cells to generate bioactive nitric oxide. Yet this endothelial dysfunction tends to correlate, not with fasting FFA levels, but with poor insulin suppressibility of FFA flux postprandially. I propose that triglycerides are synthesized and stored in endothelial cells during the postprandial period, when FFAs and insulin are jointly elevated, and that this triglyceride pool serves as a source of FFA overexposure postabsorptively--thus accounting for the endothelial dysfunction associated with insulin resistance syndrome and the role of excessive postprandial FFA flux in its induction. Since a substantial proportion of postprandial FFA flux derives, not from adipocytes, but from the fat provided by meals, these considerations may help to rationalize the documented clinical utility of very-low-fat diets for management of coronary disease.

Cellular bases for the lipid-related aspects of preeclampsia

Lipid accumulation - in hepatoytes (both subclinically and in acute fatty liver of pregnancy), in the endothelium of placental vessels ("acute atherosis"), and in the bloodstream - has been well established to be a consequence of preeclampsia. Hyperlipidemia (specifically hypertriglyceridemia) has been demonstrated to be a risk factor for the development of preeclampsia. These lipid-related aspects of preeclampsia may appear unrelated, but all are here demonstrated to provide evidence for a causative role for endothelin in the etiology of preeclampsia. Evidence for the potential of endothelin to cause lipid accumulation in hepatocytes and in endothelial cells, by means of activating G protein cascades in these cells, is presented. The capacity of typical free fatty acid constituents of triglycerides to "drive" interacellular G protein cascade-related events is also discussed - which, in this scheme, offers a plausible explanation for hypertriglyceridemia's role as a risk factor for developing preeclampsia. Additional evidence is provided which substantiates endothelin's capacity to cause most of the observed aberrations known to occur in preeclampsia.

Increased endothelial monolayer permeability is induced by serum from women with preeclampsia but not by serum from women with normal pregnancy or that are not pregnant

OBJECTIVE

To determine if endothelial monolayer permeability could be altered by serum from preeclampsia (PE).

METHODS

Confluent normal endothelial cells (ECs) were incubated with 20% serum from nonpregnant females, normal and PE pregnancies or combined with antioxidant superoxide dismutase (SOD) for 8 hr. Confluent PE ECs were incubated with 20% serum from normal pregnancies. EC barrier function of monolayer permeability was accessed by measuring EC electrical resistance (ER) and the leakage of horseradish peroxidase (HRP) passing through EC filters. Plasma concentrations of IL-8 and lipid peroxides by MDA were also measured. We determined 1) if serum from PE could affect EC permeable function; 2) if antioxidant and serum from normal pregnancies could preserve PE EC barrier function; 3) if lipid peroxides and cytokine IL-8 were increased in PE blood samples. Data are presented as mean+/-SE. ANOVA was used for statistical analysis. A p level less than 0.05 was considered statistically different.

RESULTS

1) ER was significantly decreased and HRP passage was significantly increased in ECs incubated with serum from PE compared to serum from non-pregnant and normal pregnant females (ER: 36.30+/-2.60 vs. 51.30+/-4.00 and 53.90+/-5.80 Omega x cm2, p<0.01; HRP: 0.100+/-0.020 vs. 0.014+/-0.002 and 0.022+/-0.007 DeltaOD470 nm, p<0.01, respectively). 2) ER was improved in PE ECs incubated with serum from normal pregnancies compared to controls, 52.28+/-3.13 vs. 34.50+/-3.80 Omega x cm2, p<0.01. 3) SOD attenuated decreased EC ER induced by PE serum, 55.58+/-3.61 Omega x cm2 (SOD+PE serum) vs. 42.34+/-3.24 (control) and 35.46+/-2.44 (PE serum), p<0.01, respectively. 4) Both MDA and IL-8 concentrations were higher in plasma or serum samples from PE than those in samples from nonpregnancies and normal pregnancies, MDA: 28.65+/-1.45 vs. 22.40+/-1.47 and 25.53+/-0.89 micromol/mL, p<0.01; IL-8: 5.35+/-1.08 vs. 1.69+/-0.47 and 2.28+/-0.73 pg/mL, p<0.05, respectively. Conclusions. 1) Sera from PE but not from nonpregnant women or normal pregnancies increase EC monolayer permeability. 2) Increased lipid peroxides and IL-8 are candidates altering EC barrier function. 3) Antioxidant SOD preserves increased EC monolayer permeability induced by PE serum, suggesting that EC oxidative stress may be associated with altered EC barrier function in preeclampsia.

Triglyceride-rich lipoproteins are associated with hypertension in preeclampsia

Disorders of the lipoprotein metabolism are a major cause of endothelial dysfunction that may result in hypertension and proteinuria, clinical hallmarks of preeclampsia (PE). Lipoproteins and low-density lipoprotein (LDL) subfractions were investigated in 15 women with severe PE and compared with 23 women with a normal course of pregnancy. Compared with normal pregnancy, in PE apolipoprotein (apo)B in very low-density lipoprotein was increased by 76% (P = 0.008), and the triglyceride content of intermediate dense lipoproteins (IDL) was increased by 51% (P < 0.001); cholesterol and apoB in LDL were decreased by 26% (P = 0.005) and 23% (P = 0.016), respectively. Although not significant, the LDL profile was dominated by the most buoyant LDL-1. ApoB in the most dense LDL (dLDL), namely LDL-5 and LDL-6, was significantly decreased by 49% (P < 0.001) and 55% (P < 0.001), respectively. Diastolic blood pressure was positively correlated with the triglyceride content of IDL (r = 6.31; P < 0.001 and r = 0.352; P = 0.033 by partial correlation controlling for the presence or absence of PE) and negatively correlated with the concentration of apoB in dLDL (r = -0.500; P = 0.002). In addition, IDL triglycerides correlated negatively with infant birth weight percentile (r = -0.373; P = 0.027) and positively with proteinuria (r = 0.430; P = 0.014). Low birth weight was associated with high IDL triglycerides and low rather than high concentrations of dLDL. Triglyceride-rich remnants are known to cause endothelial dysfunction. Because the triglyceride content of IDL was positively correlated with elevated blood pressure and proteinuria, triglyceride-rich remnant lipoproteins might contribute to the pathophysiology of PE.

Intracellular glutathione and lipid peroxide availability and the secretion of vasoactive substances by human umbilical vein endothelial cells after incubation with TNF-alpha

BACKGROUND

The major pathophysiologic changes observed in preeclampsia suggest that endothelial cell dysfunction plays an important role in this disorder. The pathway mediating to endothelial cell dysfunction is unknown, however, the pathogenesis of preeclampsia is thought to be related to increased oxidative stress and increased vasoconstriction. The concentration of tumor necrosis factor alpha (TNF-alpha), a cytokine produced by macrophages and many other cell types, has been observed to be significantly increased in preeclampsia. It has been hypothesized that TNF-alpha overproduction by the placenta may then may produce an increase in plasma levels and subsequent endothelial dysfunction in preeclampsia. This study investigated the effect of TNF-alpha on glutathione and lipid peroxide levels and on the secretion of vasoactive substances by human umbilical vein endothelial cells (HUVECs).

METHODS

Human umbilical vein endothelial cells were incubated for 24 h in the presence of different concentrations of TNF-alpha (0-1000 pg mL-1) that were shown in an earlier experiment to have no effects on the vitality and proliferation rate of HUVECs. The levels of reduced glutathione (GSH) and lipid peroxides (LPOs), assessed by malondialdehyde and 4-hydroxyalkenal, were measured in endothelial cell lysates. For the measurement of vasoactive substances, levels of prostacyclin (PGI2), determined by 6-keto-prostaglandin F1a, thromboxane A2 (TXA2), measured by thromboxane B2, endothelin-1 (ET-1), and nitric oxide (NO), measured by total nitrite, were assessed in endothelial cell supernatants.

RESULTS

At lower concentrations (10-100 pg mL-1), TNF-alpha increases the intracellular content of LPO and GSH, stimulates the secretion of ET-1 and TXA2, but inhibits the secretion of PGI2 in endothelial cells compared with control cells. At concentration of 1000 pg mL-1, TNF-alpha increases the secretion of PGI2 and TXA2, but it decreases the ET-1 concentration. TNF-alpha has no effect on NO secretion.

CONCLUSION

These findings demonstrate that at concentrations corresponding to values in plasma from preeclamptic women, TNF-alpha induces oxidative stress and results in altered secretion of vasoactive substances in favour of vasoconstrictors in human endothelial cells. We conclude that TNF-alpha may participate in the pathway leading to endothelial cell dysfunction seen in preeclampsia.

Production of vasoactive substances by human umbilical vein endothelial cells after incubation with serum from preeclamptic patients

OBJECTIVE

To determine the in vitro effect of serum from preeclamptic patients on the proliferation, viability and secretion of vasoactive substances by human umbilical vein endothelial cells (HUVEC).

STUDY DESIGN

HUVEC were incubated for 24h with sera from 16 preeclamptic, 19 healthy pregnant and 8 healthy nonpregnant women. Proliferation rates were determined by cell counting and vitality by trypan blue staining. The vasoactive substances, 6-keto-prostaglandin F(1alpha), nitrite and nitrate, and endothelin-1 (ET-1) were measured in endothelial cell supernatants.

RESULTS

The preeclamptic serum had no effect on cell proliferation or vitality compared with control sera. It induced more HUVEC production of ET-1, but not of prostacyclin (PGI2) or nitric oxide compared with control serum.

CONCLUSION

Preeclamptic serum appears to contain a factor(s) that specifically stimulates ET-1 secretion from HUVEC without altering cell growth or vitality.

Endothelial function in myometrial resistance arteries of normal pregnant women perfused with syncytiotrophoblast microvillous membranes

OBJECTIVE

To investigate the effects of syncytiotrophoblast microvillous membranes (STBM) in concentrations, found in vivo in women with pre-eclampsia, on endothelial function in isolated resistance arteries.

SETTING

Department of Obstetrics and Gynaecology, Huddinge University Hospital, Stockholm.

SAMPLE

Twenty-nine myometrial resistance arteries isolated from biopsies of healthy term pregnant women, obtained during caesarean section.

METHODS

The myometrial arteries were mounted in a pressure arteriograph and perfused intraluminally for three hours with STBM (20 to 2000ng/mL) or with erythrocyte membranes or physiological salt solution as controls, all substituted with 0.5% bovine serum albumin. Bradykinin concentration-response curves were performed before and after perfusion.

MAIN OUTCOME MEASURES

The bradykinin concentrationresponse curves were fitted to the Hill equation and maximal dilation and the pEC50 values were determined from these fits. Differences within groups were analysed with a paired Student's t test. Electron microscopic evaluation of the endothelium was performed.

RESULTS

Neither STBM nor erythrocyte membrane perfusion affected maximal dilation or the pEC50 values of the bradykinin concentration-response curves at any concentration. Examination by electron microscopy showed no obvious damage to the endothelium after perfusion with STBM or erythrocyte membranes.

CONCLUSION

Perfusion with STBM in concentrations up to 100 times those reported in pre-eclampsia has no significant effect on bradykinin-mediated dilation in isolated myometrial arteries.

The endothelium: a gynecological and obstetric point of view

The endothelium, long considered merely an inert, semipermeable membrane between blood and the vessel wall, is now viewed as an important, large and highly active endocrine organ which is responsible for a number of vital physiological functions. In this editorial we will discuss the important role of the endothelium and endothelial (dys)function in health and disease, with particular focus on postmenopausal cardiovascular disease and preeclampsia.

Cytosolic triglycerides and oxidative stress in central obesity: the missing link between excessive atherosclerosis, endothelial dysfunction, and beta-cell failure?

Central obesity is increasingly recognized as a risk factor for atherosclerosis and type 2 diabetes mellitus. Here we present a hypothesis that may explain the excess atherosclerosis, endothelial dysfunction and progressive beta-cell failure. Central obesity is associated with increased cytosolic triglyceride stores in non-adipose tissues such as muscles, liver and pancreatic beta-cells. A high cytosolic triglyceride content is accompanied by elevated concentrations of cytosolic long-chain acyl-CoA esters, the metabolically active form of fatty acids. These esters inhibit mitochondrial adenine nucleotide translocators, resulting in an intramitochondrial ADP deficiency. In vitro, such ADP deficiency is a potent stimulator of mitochondrial oxygen free radical production, and we assume that this mechanism is also active in vivo. The decline of organ function with normal ageing is thought to be due, at least partly, to a continuous low-grade mitochondrial oxygen free radical production. In tissues containing increased cytosolic triglyceride stores this process will be accelerated. Tissues with a high-energy demand or poor free radical scavenging capacity, such as pancreatic beta-cells, are likely to be more susceptible to this process. This is how we explain their gradual dysfunctioning in central obesity. Likewise we propose that the enhanced production of oxygen free radicals in endothelial cells, or vascular smooth muscle cells, leads to the increased subendothelial oxidation of LDL and atherosclerosis, as well as to the endothelial dysfunction and microalbuminuria.

Is carbohydrate metabolism altered among women who have undergone a preeclamptic pregnancy?

OBJECTIVE

To compare women after a preeclamptic pregnancy with women after a normal pregnancy with respect to androgenic-anabolic status and carbohydrate and lipid profiles.

METHOD

Twenty-one patients and 22 controls were followed up to 26-119 weeks after delivery. Blood was sampled for analyses of insulin, glucose, insulin growth factor-1, lipids, androgens, sex hormone-binding globulin (SHBG) and uric acid. Anthropometric data and blood pressure were recorded. Data are presented as median and ranges (within parentheses) or mean +/- SEM where appropriate. Comparisons were made by unpaired t test or Mann-Whitney U test, respectively.

RESULTS

Significantly higher values were found in the preeclampsia than in the control group for fasting insulin, fasting glucose, fasting insulin resistance index (FIRI, fasting glucose x fasting insulin/25), serum triglycerides, uric acid and blood pressure. There were no differences in androgen status and IGF-1 levels.

CONCLUSION

Patients with a recent history of preeclampsia demonstrate signs of relative insulin resistance, hypertriglyceridemia and hyperuricemia as well as increased blood pressure as compared with women who had a normal pregnancy. However, in contrast to other women with insulin resistance, they have a normal androgen status.

Interaction of the protein C/protein S anticoagulant system, the endothelium and pregnancy

Normal pregnancy is associated with significant changes in haemostasis, lipid metabolism and endothelial function. This suggests that maternal adaptation in these systems is required for successful pregnancy outcome. A number of acquired and heritable prothrombotic abnormalities are associated with complications in pregnancy. A common feature of these abnormalities is their ability to alter endothelial function or the protein C/protein S system and increase thrombin generation. In this review the normal function of the endothelium and the protein C/protein S system is detailed. The changes which characterize normal and complicated pregnancies are outlined and the evidence for the impact of heritable and acquired disorders of the protein C/protein S system on pre-eclampsia and fetal loss are discussed.

Vascular smooth muscle oxygen consumption is reversibly stimulated by sera from women with preeclampsia

OBJECTIVE

Preeclampsia is a complication of pregnancy that causes maternal vasoconstriction and hypertension. The disease may progress to eclampsia, which is thought to be related to cerebral vasospasm. Although there is evidence for more than one circulating factor that causes endothelial cell dysfunction in preeclampsia, little work has focused on the possibility that vascular smooth muscle function might be directly stimulated by a circulating factor. The aim of this study was to determine whether such a factor or factors could be detected by the vessels.

STUDY DESIGN

Excessive vascular smooth muscle oxygen consumption was used as a screen for metabolic stimulation because pathologic arterial constriction would require oxidative metabolism to generate adenosine triphosphate. De-endothelialized porcine carotid artery (a well-validated model of human arterial contractile function) was exposed to sera from patients with preeclampsia (1:30 dilution) in a sealed chamber with an oxygen electrode, and the rate of oxygen consumption by the tissue was measured. Comparisons with the effects of sera from matched normal pregnant patients and from nonpregnant women were made.

RESULTS

Exposure of vascular smooth muscle to sera from women with preeclampsia for 90 minutes resulted in greater oxygen consumption by the tissue (0.66 +/- 0.16 micromol O2 /min per gram of dry weight) than did exposure to sera of matched pregnant and nonpregnant control subjects (0.34 +/- 0.08 micromol O2 /min per gram of dry weight, P <.001, and 0.29 +/- 0.03 micromol O2 /min per gram of dry weight, P <.001, respectively). This stimulation was completely reversed by rinsing.

CONCLUSIONS

There is a factor in the circulation of women with preeclampsia that has the reversible effect on vascular smooth muscle of accelerating oxygen consumption. We discuss the implications of this observation in terms of known aspects of vascular smooth muscle contractile function.

Pathogenesis of preeclampsia: a comprehensive model

The objective of this review was to provide a comprehensive and practical concept on the pathogenesis of preeclampsia on the basis of the currently available scientific evidence. A MEDLINE search was performed of English-language articles published between 1966 and 1997, supplemented with references cited in relevant research articles. Using our data sources, we developed a scheme describing the sequence of events between implantation and the time of manifest clinical disease characterized by generalized endothelial cell dysfunction. A yet unidentified toxic circulating factor released by the ischemic placenta, is held responsible for the impaired endothelial cell function. Particularly, epidemiological studies point to a concept in which immune maladaptation to the fetal allograft plays a key role in causing defective placentation leading to placental ischaemia. The incidence of preeclampsia in sisters and daughters of women who had had preeclampsia is raised. Disease states with vascular involvement, like chronic hypertension and diabetes mellites, are associated with an increased risk for preeclampsia. Recently subclinical abnormalities in hemostasis, metabolism and volume homeostasis have been described in patients with a history of preeclampsia. Placental ischemia secondary to defective placentation, a prerequisite for the development of preeclampsia, has a multifactorial origin consisting of three major components: immune maladaptation, genetic predisposition, and vascular mediated factors. Probably, a summation of these factors will determine whether a pregnant woman is to develop the syndrome. The recently described subclinical abnormalities in hemostasis, metabolism, and vascular function in patients with a history of preeclampsia might give the clinician the opportunity to reduce the recurrence risk by pharmacotherapeutic intervention.

Preeclamptic nephropathy -- an endothelial lesion. A morphological study with a review of the literature

OBJECTIVE

We investigated wether an endothelial lesion, postulated in pathogenesis of preeclampsia (PE) in general, is also pathogenetically relevant in the characteristic renal lesions of PE, presenting as special glomerular alterations, designated as "preeclamptic nephropathy".

STUDY DESIGN

Renal biopsies of 90 women with PE were analyzed by light microscopy (LM), immunohistology (IH) and electron microscopy (EM). Corresponding with clinical data clinicomorphological correlations were performed.

RESULTS

In IH and EM the altered glomeruli demonstrate an endothelial lesion. Consecutive morphological reactions could be revealed by EM, allowing a subdivision in different stages of disease. The late stage indicates the reversibility of these renal lesions. Close correlations were found between clinical and morphological data. Focal glomerulosclerosis presents a hyperperfusion lesion, developing only facultatively in PE as a result of hyperfiltration.

CONCLUSION

In preeclamptic nephropathy the first morphological substrate of renal changes with the key to pathogenesis presents itself as an endothelial lesion. This results in a disturbance of glomerular basement membrane permeability and in an imbalance of different mediator systems, with dominance of vasoconstrictive reactions but also coagulative-, reparation-, and proliferation-processes, leading to the characteristic glomerular alterations of preeclamptic nephropathy.

Serum from women with preeclampsia partially corrects the abnormal in vitro prostacyclin secretion of preeclamptic villous cytotrophoblasts but not that of prostaglandin E2 or endothelin-1

OBJECTIVE

This study was conducted (1) to determine in vitro placental villous cytotrophoblast secretion of prostacyclin, prostaglandin E2, and endothelin-1, (2) to examine the effect of serum from normal and preeclamptic women on secretion of these vasoactive substances, and (3) to determine whether responses to these sera by cytotrophoblasts from preeclamptic pregnancies are different from those of normal pregnancies.

STUDY DESIGN

Cytotrophoblasts isolated from human placentas collected at cesarean section from normal and preeclamptic women were incubated for 20 hours in 20% (vol/vol) sera from preeclamptic or gestational age-matched normal pregnant women. Levels of prostacyclin (measured as 6-keto-prostaglandin F1alpha), prostaglandin E2, and endothelin-1 were measured in cytotrophoblast supernatants.

RESULTS

In normal pregnancy sera preeclamptic cytotrophoblasts secreted significantly lower amounts of prostacyclin and prostaglandin E2 but higher amounts of endothelin-1 than did normal cytotrophoblasts. In preeclamptic sera the abnormality of prostacyclin secretion by preeclamptic cytotrophoblasts was partially corrected, but there was no effect on prostaglandin E2 or endothelin-1 secretion. Preeclamptic sera had no effect on secretion by normal cytotrophoblasts.

CONCLUSIONS

The differences between normal and preeclamptic cytotrophoblasts in prostacyclin, PGE2, and endothelin-1 secretion and in response to preeclamptic serum suggest altered arachidonic acid metabolism in preeclampsia.

Endothelial adhesion molecules and leukocyte integrins in preeclamptic patients

Endothelial cell activation is important in the pathogenesis of preeclampsia; however, the nature of the activation is unknown. We investigated 22 patients with preeclampsia. 29 normotensive pregnancies, and 18 nonpregnant women to test the hypothesis that serum from preeclamptic patients induces expression of intercellular adhesion molecule-1 (ICAM-1) and vascular adhesion molecule-1 (VCAM-1) and stimulates intracellular free calcium concentrations [Ca2+]i in cultured endothelial cells. We then asked whether the corresponding integrin adhesive counter receptors lymphocyte function-associated antigen-1 (CD11a/CD18), macrophage-1 antigen (CD11b/CD18), p150,95 (CD11c/CD18), and very late activation antigen-4 (CD49/CD29) are increased in patients with preeclampsia. In the pregnant women, the measurements were conducted both before and after delivery. Integrin expression was measured by fluorescent antibody cell sorting analysis using monoclonal antibodies. ICAM-1 and VCAM-1 were analyzed on endothelial cells by enzyme-linked immunosorbent assay. [Ca2+]i was measured with fura 2. Serum from preeclamptic patients increased endothelial cell ICAM-1 expression but not VCAM-1 expression. Preeclamptic patients' serum also increased [Ca2+]i in endothelial cells compared with serum from normal nonpregnant or normal pregnant women. Endothelial cell [Ca2+]i concentrations were correlated with the ICAM-1 expression in preeclamptic patients (r = .80, P < .001) before but not after delivery. Expression of the integrin counter receptors on leukocytes was similarly increased in preclampsia and normal pregnancy compared with the nonpregnant state. The expression decreased significantly after delivery in both groups. Our results demonstrate that serum from preeclamptic women induces increased ICAM-1 surface expression on endothelial cells, while the expression of the integrin counterreceptors was not different. The effect on endothelial cells may be related to an increase in [Ca2+]i. The effect on cultured endothelial cells and the rapid decrease after delivery suggests the presence of a circulating serum factor which increases endothelial cell [Ca2+]i and enhances adhesion molecule expression.

Evidence of endothelial activation and endothelial activators in cord blood of infants of preeclamptic women

OBJECTIVE

In preeclampsia markers of endothelial activation (e.g., increased cellular fibronectin and activities that alter in vitro endothelial function (e.g., stimulation of nitric oxide and prostacyclin generation) are increased in the maternal circulation. We tested preeclamptic infant blood for these markers and activities and correlated these findings with fetal growth.

STUDY DESIGN

Plasma was obtained from 17 term nulliparcus preeclamptic and normal pregnant women and their infants and from 8 additional preeclamptic mother-baby pairs from earlier gestations. Plasma cellular fibronectin and production of nitric oxide and prostacyclin by cultured endothelial cells exposed to 2% plasma were measured.

RESULTS

Cellular fibronectin was higher in maternal plasma of preeclamptic than nonpregnant women (6.1 +/- 0.29 vs 4.2 +/- 0.27 microgram/ml, p < 0.01), as were stimulated endothelial nitric oxide and prostacyclin production (nitric oxide 42.5 +/- 3.9 vs 26.9 +/- 2.3 nmol nitrite/microgram protein/24 hours, p < 0.05; prostacyclin 261.7 +/- 31.2 vs 151.9 +/- 18.7 pg prostaglandin F1 alpha/microgram protein/24 hours, p < 0.05). In the preeclamptic infants cellular fibronectin was also greater (3.3 +/- 0.15 vs 2.6 +/- 0.14 microgram/ml, p < 0.01), as was endothelial nitric oxide production in response to the plasma (24.4 +/- 1.1 vs 21.4 +/- 0.09 mumol/L nmol nitrite/microgram protein/24 hours, p < 0.05). Prostacyclin production was not significantly different. In preeclamptic infants across a wide gestational age there was no correlation of endothelial activation and fetal growth.

CONCLUSIONS

Infants of women with preeclampsia may be affected by endothelial dysfunction, as well as reduced uteroplacental perfusion.

Distinct factors in plasma of preeclamptic women increase endothelial nitric oxide or prostacyclin

The pathogenesis of preeclampsia is proposed to be due to uncharacterized circulating factors that activate endothelial cells. Support for this hypothesis is provided by in vitro activation of endothelial cells by plasma from preeclamptic women, eg, increased nitric oxide and prostacyclin generation. We performed molecular sizing, lipid extraction, and lipoprotein fractionation of plasma from normal pregnant and preeclamptic women and determined the ability of these plasma fractions to increase nitric oxide or prostacyclin generation by endothelial cells. Fractions from plasma of preeclamptic women were consistently more active than fractions from normal pregnant women, although characterization was qualitatively similar. The factors stimulating nitric oxide and prostacyclin were different. The factor (or factors) stimulating nitric oxide generation was extractable by charcoal and present in lipid extracts and lipoprotein isolates with a molecular weight greater that 1.5 million daltons, which is characteristic of a lipoprotein or lipoprotein aggregate. By contrast, activity to stimulate prostacyclin persisted after charcoal stripping or lipoprotein removal, partitioned to the aqueous fraction, and had a molecular weight of approximately 50,000 D. Two distinct factors in the blood of preeclamptic women alter endothelial function in vitro. This information should guide the search for circulating factors contributing to the pathophysiology of preeclampsia.

Fasting serum triglycerides, free fatty acids, and malondialdehyde are increased in preeclampsia, are positively correlated, and decrease within 48 hours post partum

OBJECTIVE

We tested the hypothesis that serum free (nonesterified) fatty acid and triglyceride concentrations are increased in nulliparous women with preeclampsia relative to women with uncomplicated pregnancies and that these lipids decrease post partum, consistent with the known resolution of clinical symptoms. The relationships between serum concentrations of these lipids and the lipid peroxidation metabolite malondialdehyde were also examined.

STUDY DESIGN

Predelivery and 24 to 48 hour postpartum venous blood samples were collected from eight women with preeclampsia and nine women with uncomplicated pregnancies after an 8- to 10-hour fast. Sera were analyzed for concentrations of triglycerides, free fatty acids, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and malondialdehyde.

RESULTS

Antepartum serum triglyceride and free fatty acid concentrations were increased approximately twofold in women with preeclampsia relative to uncomplicated pregnancies (p <0.02 and 0.004, respectively). Total, high-density lipoprotein, and low-density lipoprotein cholesterol concentrations did not differ between groups. Concentrations of all lipids decreased significantly in both groups within 48 hours post partum. However, triglyceride and free fatty acid concentrations remained higher in women with preeclampsia (p<0.006, both variables). Triglyceride and free fatty acid concentrations correlated positively, both ante partum (R2 0.42, p<0.01) and post partum (R2 0.39, p<0.02). Antepartum concentrations of malondialdehyde were 50% higher in women with preeclampsia (p<0.01) and decreased post partum (p <0.02) but did not decrease in controls (p = 0.07). Antepartum serum triglycerides and free fatty acids correlated positively with malondialdehyde concentrations (R2 0.38, p <0.02, both cases).

CONCLUSION

Triglycerides and free fatty acids, but not cholesterol, are increased in preeclampsia and correlate with the lipid peroxidation metabolite malondialdehyde. We speculate that these interactions may contribute to endothelial cell dysfunction in preeclampsia.

Preeclampsia: the effects of serum on endothelial cell prostacyclin, endothelin, and cell membrane integrity

OBJECTIVE

Our purpose was to determine whether serum from women with preeclampsia or gestational hypertension (1) decreased endothelial cell prostacyclin, (2) increased endothelial cell endothelin, and (3) caused endothelial cell damage.

STUDY DESIGN

Production of 6-keto-prostaglandin F1 alpha and endothelin by cultured endothelial cells was measured after 48 hours' incubation with sera from 23 nonpregnant women, 23 normal pregnant women, 12 women with preeclampsia, and 11 women with gestational hypertension. Structure damage of endothelial cells was assessed by a chromium release assay.

RESULTS

Serum from normal pregnant women induced more endothelial prostacyclin but less endothelin than did serum form nonpregnant women (p<0.05). No difference was found between normal pregnant and hypertensive pregnant women for prostacyclin production, but serum of preeclamptic women induced less endothelin production than did that of normal pregnant women (p<0.05). Chromium 51 release by endothelial cells was similar between normal pregnant and hypertensive pregnant groups.

CONCLUSIONS

Serum from preeclamptic women stimulates less endothelin production than does serum from normal pregnant women but does not alter prostacyclin production and is not cytotoxic to endothelial cells after short-term incubation.

Endothelial cell proliferation is suppressed by plasma but not serum from women with preeclampsia

OBJECTIVES

Evidence has been sought for a circulating factor derived from the placenta that suppresses endothelial cell proliferation and hence contributes to the maternal endothelial cell disturbances of preeclampsia.

STUDY DESIGN

The effects of sera and plasmas from women with proteinuric preeclampsia and from matched normal pregnant control women on endothelial cell proliferation were compared. The recovery of endothelial cell inhibitory activity from syncytiotrophoblast microvesicles added to male blood and prepared as plasma or serum was determined to investigate the possible placental origin of the inhibitory factor.

RESULTS

Sera from women with preeclampsia did not inhibit endothelial cell proliferation. In contrast, plasma from preeclamptic women significantly suppressed endothelial cell growth at 20% dilution compared with controls, and suppression was more pronounced in severe preeclampsia. The inhibitory activity of syncytiotrophoblast microvesicles added to blood could not be recovered from serum, only from plasma, which may explain why there was no suppression with sera from preeclamptic women.

CONCLUSIONS

These results confirm that there is a blood-borne endothelial cell suppressive factor in preeclampsia that may be derived from the placenta.

Plasma of preeclamptic women stimulates and then inhibits endothelial prostacyclin

We propose that the dichotomy between the in vivo reduction in intravascular prostacyclin production that occurs in preeclampsia and the in vitro stimulatory effect of plasma from preeclamptic patients on endothelial cell prostacyclin production is due to differential effects of chronic versus acute exposure to the plasma. We studied the acute versus chronic effects of 2% plasma from healthy pregnant and preeclamptic subjects by measuring endothelial prostacyclin production at different time periods after exposure to plasma. To determine whether such effects were specific to prostacyclin, we also measured prostaglandin E2 production. To determine whether chronic changes in prostacyclin production resulted from altered cellular responsiveness, we stimulated cells that had been exposed to plasma for 72 hours with arachidonic acid and measured prostaglandin production. Preliminary characterization of the plasma factor or factors responsible for alterations in prostaglandin production was performed. After 24 hours cells exposed to plasma from preeclamptic women produced more prostacyclin and prostaglandin E2 than cells exposed to plasma from healthy pregnant women. In contrast, after 72 hours exposure to plasma from preeclamptic women resulted in less endothelial cell prostacyclin production than exposure to plasma from healthy pregnant women, but there were no such differences in prostaglandin E2 production. Cells that had been exposed to plasma from preeclamptic women for 72 hours produced less prostacyclin but the same quantity of prostaglandin E2 after stimulation with arachidonic acid than cells exposed to plasma from healthy pregnant women. The plasma factor or factors responsible for altered prostacyclin production were sensitive to heat, acid, and proteases. In contrast to acute exposure, chronic exposure to plasma from preeclamptic women alters endothelial cells to result in decreased prostacyclin production, an observation consistent with in vivo findings.