Endothelial Cell Dysfunction In Preeclampsia Research Articles

A novel peptide relieves endothelial cell dysfunction inpreeclampsia by regulating the PI3K/mTOR/HIF1α pathway.

Preeclampsia (PE) is a pregnancy-specific complication characterized by hypertension and proteinuria, and it is one of the primary global causes of maternal and perinatal mortality. Poor remodeling of placental arteries and endothelial dysfunction serve important roles in the pathogenesis of PE. Peptide derived from complement C4 A chain (PDCC4) was identified in our previous peptidome analysis of serum from patients with PE. The present study aimed to investigate the effect of PDCC4 on endothelial dysfunction in PE. TNF-α stimulated HUVECs were employed to mimic endothelial dysfunction in PE, and Cell Counting Kit 8 assay, wound healing assay, tube formation assay, RNA-sequencing (seq) and western blot analysis were performed using HUVECs. Moreover, an in vivo model of PE was established using pregnant rats treated with lipopolysaccharide (LPS), and blood pressure monitoring, histopathological examination, ELISA and immunohistochemistry were performed on rats. It was found that TNF-α impaired proliferation, migration and tube formation of HUVECs, but pretreatment with PDCC4 moderated these effects. RNA-seq and western blotting demonstrated that the PI3K/mTOR/HIF1α signaling pathway was activated by PDCC4, and a selective PI3K inhibitor reversed the protective function of PDCC4 on TNF-α stimulated HUVECs. Additionally, PDCC4 alleviated hypertension, histopathological changes of placenta and kidney and the expression levels of endothelial injury markers and inflammatory cytokines induced by LPS in rats. These results suggested that PDCC4 relieved endothelial dysfunction in PE via PI3K/mTOR/HIF1α signaling pathway and may be a potential therapy for PE.

Role of Activin A in the Pathogenesis of Endothelial Cell Dysfunction in Preeclampsia.

This chapter describes the methodologies which may be used in evaluating in vitro endothelial cell dysfunction in preeclampsia.

Up-regulation of CD81 inhibits cytotrophoblast invasion and mediates maternal endothelial cell dysfunction in preeclampsia

Preeclampsia (PE) is initiated by abnormal placentation in the early stages of pregnancy, followed by systemic activation of endothelial cells of the maternal small arterioles in the late second or third trimester (TM) of pregnancy. During normal pregnancy, placental cytotrophoblasts (CTBs) invade the maternal uterine wall and spiral arteries, whereas this process is interrupted in PE. However, it is not known how the malformed placenta triggers maternal endothelial crisis and the associated manifestations. Here, we have focused on the association of CD81 with PE. CD81, a member of the tetraspanin superfamily, plays significant roles in cell growth, adhesion, and motility. The function of CD81 in human placentation and its association with pregnancy complications are currently unknown. In the present study, we have demonstrated that CD81 was preferentially expressed in normal first TM placentas and progressively down-regulated with gestation advance. In patients with early-onset severe PE (sPE), CD81 expression was significantly up-regulated in syncytiotrophoblasts (STBs), CTBs and the cells in the villous core. In addition, high levels of CD81 were observed in the maternal sera of patients with sPE. Overexpressing CD81 in CTBs significantly decreased CTB invasion, and culturing primary human umbilical vein endothelial cells (HUVECs) in the presence of a high dose of exogenous CD81 resulted in interrupted angiogenesis and endothelial cell activation in vitro. Importantly, the phenotype of human PE was mimicked in the CD81-induced rat model.

The NOX2-derived reactive oxygen species damaged endothelial nitric oxide system via suppressed BKCa/SKCa in preeclampsia

The endothelial nitric oxide (NO) system may be damaged in preeclampsia; however, the involved mechanisms are unclear. In this study, we used primary human umbilical vein endothelial cells (HUVECs) to evaluate the endothelial NO system in preeclampsia and to determine the underlying mechanisms that are involved. We isolated and cultured HUVECs from normal and preeclamptic pregnancies and evaluated endothelial NO synthase enzyme (eNOS) expression and NO production. Whole-cell K+ currents and oxidative stress were also determined in normal and preeclamptic HUVECs. Compared with normal HUVECs, eNOS expression, NO production and whole-cell K+ currents in preeclamptic HUVECs were markedly decreased, whereas oxidative stress was significantly increased. The decreased K+ currents were associated with damaged Ca2+-activated K+ (KCa) channels, especially the large (BKCa) and small (SKCa) conductance KCa channels, and were involved in the downregulated eNOS expression in preeclamptic HUVECs. Moreover, the increased oxidative stress detected in preeclamptic HUVECs was mediated by NADPH (nicotinamide adenine dinucleotide phosphate) oxidase 2 (NOX2)-dependent reactive oxygen species overproduction that could downregulate whole-cell K+ currents, eNOS expression and NO production. Taken together, our study indicated that the increased oxidative stress in preeclamptic HUVECs could downregulate the NO system by suppressing BKCa and SKCa channels. Because the damaged NO system was closely related to endothelial dysfunction, this study provides important information to further understand the pathological process of endothelial cell dysfunction in preeclampsia.

Intracellular actions of inositol messengers and their relationship with the metabolic syndrome

Metabolic alterations occur along with immunological alterations, abnormal placental development and endothelial cell dysfunction in preeclampsia. Typical features of placental alterations are an inadequate/incomplete trophoblast invasion of maternal spiral arteries and acute atherosis. Phosphoinositide 3-kinase (PI3-K)/Akt signaling pathway holds a pivotal role in intracellular metabolic pathways as it regulates endothelial cell survival, migration, tube formation and nitric oxide production. The inositol second messenger system (myo- inositol and D-chiro inositol) is involved in metabolic and cell signaling pathways. Pyruvate dehydrogenase complex (PDC) is at the interface between glycolysis and the citric acid cycle and is crucial to the generation of ATP, acetyl CoA and NADH by mitochondria. We showed that the putative insulin mediator inositol phosphoglycan containing D-chiro inositol (IPG-P) has a sigmoidal inhibitory action on PDK in addition to its known linear stimulation of PDP. Thus, at critical levels of these mediators this sigmoidal/linear model amplifies the switchover from the inactive to active form of PDC, a ‘push- pull’ system that combined with the hormonal control of IPG-P, indicates a powerful regulatory function via inhibition of PDK. The presence of zinc is of interest in relation to our reported effects of zinc ions on PDP and PDH kinases, and in the context of the cardioprotective effects of zinc on vascular ischemia-reperfusion injury. This resetting of the PDC to the active non-phosphorylated state and formation of acetyl-CoA may be enhanced by the effect of zinc on the activation of enolase in the glycolytic pathway and by the regulation of the phosphorylation state of the insulin receptor and thus downstream pathways favouring the provision of pyruvate from glucose. The counter effect of zinc in depressing acetyl-CoA oxidation is obtained via inhibition of key enzymes of the tricarboxylic acid cycle driving acetyl-CoA towards the lipogenic route. Manganese is present in high concentrations in IPG-A type (containing myo-inositol) and coordinates lipid synthesis via manganese activation of different enzymes. Characterization of the intracellular action of inositol messengers in the context of a metabolic disease like preeclampsia helps to understand the underlying biochemical mechanisms that occur in placenta and endothelial cells.

Role of activin A in the pathogenesis of endothelial cell dysfunction in preeclampsia.

Circulating markers for endothelial activation such as endothelin-1 (ET-1), ICAM-1 and VCAM-1 are elevated in women with preeclampsia. Using human umbilical vein endothelial cells (HUVECs) as an in vitro model of the maternal vasculature, we show that activin A and preeclamptic serum upregulate ET-1, ICAM-1, and VCAM-1 in HUVECs. Further, we show that follistatin, a specific binding protein for activin, mitigates the upregulation of ET-1, ICAM-1 and VCAM-1 in HUVECs exposed to either activin A or preeclamptic serum. These data are consistent with activin A contributing to the pathophysiology of preeclampsia and suggest that therapies targeting activin signalling are worth exploring.

Implication du stress oxydant dans la physiopathologie de la pré-éclampsie : mise au point

Preeclampsia is a leading cause of pregnancy complications and affects 3–7% of pregnant women. Pathophysiology of preeclampsia is still unclear. According to the two-stage model of preeclampsia, the abnormal and hypoperfused placenta (stage 1) releases factors to the bloodstream, which are responsible for the maternal symptoms (stage 2), characterised by a systemic inflammation and endothelial dysfunction. Oxidative stress plays an important role in the pathophysiology of the preeclampsia and could be the common denominator between the two. This review summarizes the current knowledge of a new potential etiology of the disease, with a special focus on oxidative stress. We also review the different factors that have been proposed to cause endothelial cell dysfunction in preeclampsia, and trials investigating the role of antioxidant supplementation in preeclampsia.

Study on p38 mitogen activated protein kinase in vascular endothelial cells dysfunction in preeclampsia

To study expression and activation of p38 mitogen activated protein kinase (MAPK) in vascular endothelial cells dysfunction in preeclampsia. From Sept. 2009 to Mar. 2010, 54 pregnant women underwent deliveries in the First Affiliated Hospital of Chongqing Medical University were enrolled in this study, including 20 patients in mild preeclampsia group, 16 patients in severe preeclampsia group and 18 women with term cesarean section without perinatal complications as control group. Placental endothelial cells were labeled by CD₃₄ to assay microvessel density (MVD) of each group. Immunohistochemical SP and western blot were used to detect localization and expression of p-p38 MAPK protein, respectively. The levels of sera soluble fms-like tyrosine kinase-1 (sFlt-1) and soluble endoglin (sEng) were measured by ELISA. (1) The MVD of placenta were 103 ± 3 in control group, 81 ± 5 in mild preeclampsia group and 63 ± 4 in severe group, respectively, which showed statistical difference among each group (P < 0.05). (2) The expression of p38 MAPK protein were 0.84 ± 0.05 in control group, 0.90 ± 0.14 in mild group and 0.86 ± 0.18 in severe group, which did not reach remarkable difference among each group (P > 0.05). The expression of p-p38 MAPK protein were 0.13 ± 0.05 in control group, 0.59 ± 0.12 in mild group and 1.16 ± 0.18 in severe group, which show statistical difference among each group (P < 0.05). (3) The localization of p-p38 was in trophoblast, endothelial cells and a few stromal cells in placenta. (4) The level of sFlt-1 and sEng: (1) The concentration of sFlt-1 and sEng were (5.2 ± 0.3) and (10.9 ± 0.4) µg/L in control group, (12.5 ± 1.2) and (20.4 ± 5.3) µg/L in mild group and (19.3 ± 3.0) and (29.5 ± 3.7) µg/L in severe group. When drawing paired comparison in those groups, the differences showed statistical difference (P < 0.05). (2) There were positive correlations between p-p38 MAPK protein levels and the concentrations of serum sFlt-1, sEng in preeclampsia groups (r = 0.68, P < 0.05; r = 0.87, P < 0.05). The remarkable activation of the p38 MAPK in the placenta of patients with preeclampsia induced the increased levels of sFlt-l and sEng in maternal serum, which confer the injury of vascular endothelial cells that caused the significant decline of MVD in placentas. p38 MAPK signaling might be one of the key pathways in vascular endothelial cell dysfunction in preeclampsia.

Can exercise prevent preeclampsia?

Can exercise prevent preeclampsia?

Protein composition of microparticles shed from human placenta during placental perfusion: Potential role in angiogenesis and fibrinolysis in preeclampsia

Shedding of syncytiotrophoblast microparticles (MPs) from placenta to maternal blood occurs in normal pregnancy and is enhanced during preeclampsia (PE). The syncytiotrophoblast synthesizes plasminogen activator inhibitors (PAIs) which regulate fibrinolysis, as well as soluble forms of the fms-like tyrosine kinase (sFlt-1) and endoglin, which exert anti-angiogenic actions. An increase in the ratio of PAI-1/PAI-2 and elevated levels of sFlt-1 and sEng in maternal serum are linked to placental damage and maternal endothelial cell dysfunction in PE. The goal of the current study was to determine whether MPs released to maternal perfusate during dual perfusion contain these factors associated with placental pathophysiology in PE. Initially, high levels of alkaline phosphatase activity and Annexin V binding were found in MPs isolated by sequential centrifugation of maternal perfusates at 10,000 and 150,000×g(10 K and 150 K MPs), indicating their plasma membrane origin. ELISA revealed the presence of these factors at the following relative levels: Eng>PAI-2⋙PAI-1>sFlt-1. Based on comparisons of their concentration in perfusates, MPs, and MP-free 150 K supernatants, we determined that MPs constitute a significant portion of Eng released by placenta. Flow cytometric analysis of 10 K MPs supported the levels of expression found by ELISA and indicated that Eng and PAI-2 were almost exclusively localized to the surface of MPs, a site with biological potential. These results indicate that MPs shed from the syncytial surface express factors which may alter the fibrinolytic and angiogenic balance at the maternal–fetal interface and play a role in the pathophysiology of PE.

The Role of Placental Oxidative Stress and Lipid Peroxidation in Preeclampsia

Preeclampsia is a complex multisystem disorder exclusively seen in human species that is characterized by hypertension and proteinuria. This disorder has the highest maternal and fetal morbidity and mortality of all pregnancy-related complications. Growing evidence suggests that placental oxidative stress is involved in the etiopathogenesis of preeclampsia. Reduced perfusion as a result of abnormal placentation leads to ischemia reperfusion injury to the placenta. Placental oxidative stress, which results from the ischemia reperfusion injury, is being increasingly reported to be involved in the etiopathogenesis of preeclampsia. It has been proposed as a promoter of lipid peroxidation and the endothelial cell dysfunction that is commonly seen in this condition. Although preeclampsia is characterized by increased lipid peroxidation and diminished antioxidant capacity, there is no consensus regarding causality of lipid peroxidation in preeclampsia. In this article, we address the question of the biologic association of lipid peroxidation and preeclampsia. Lipid peroxidation and leukocyte activation may play a pivotal role in endothelial cell dysfunction. We also review the different factors that have been proposed to cause endothelial cell dysfunction in preeclampsia, trials investigating the role of antioxidant supplementation in preeclampsia, and the lack of consensus among the trials. Additional longitudinal studies are necessary to determine if the various oxidative stress biomarkers estimated early in pregnancy can be narrowed to a single marker for predicting preeclampsia. Obstetricians & Gynecologists, Family Physicians. After completion of this article, the reader should be able to recall that placental oxidative stress is involved in the etiopathogenesis of preeclampsia, state that placental oxidative stress results from ischemic reperfusion injury, and explain that ischemic reperfusion injury is a promoter of lipid peroxidation and endothelial cell dysfunction seen in preeclampsia.

Generation of Reactive Oxygen Species by Neutrophils and Endothelial Cell Injury in Normal and Preeclamptic Pregnancies

The aim of this study was to investigate the role of neutrophil-derived reactive oxygen species on endothelial cell dysfunction in preeclampsia. We first assessed the correlation between nitrite and superoxide anion production in normal nonpregnant (n=10), normal pregnant (n=15), and preeclamptic women (n=12). We then examined neutrophil-mediated oxygen radical damage to human umbilical vein endothelial cells in vitro. Neutrophil superoxide release was measured by cytochrome C reduction; nitrite release was measured by the modified Griess reaction, and endothelial cell injury was measured by 51Cr release. N-formyl-methionyl-leucyl-phenylalanine-stimulated superoxide release by neutrophils was significantly increased in women with preeclampsia compared with the other 2 groups. Nitrite release by neutrophils was significantly decreased in preeclampsia compared with normal pregnancy. When neutrophils were pretreated with superoxide dismutase, nitrite release by neutrophils did not differ between normal pregnancy and preeclampsia, suggesting that excess superoxide anion in preeclampsia could reduce bioavailability of nitric oxide through neutrophil autocrine function. Neutrophil-mediated endothelial cell injury was significantly greater in women with preeclampsia than in the other 2 groups. Hydrogen peroxide was important in neutrophil-mediated endothelial cell injury in preeclampsia as catalase inhibited endothelial cell injury. When neutrophils were pretreated with NG-nitro-L-arginine methyl ester, neutrophil-mediated endothelial cell injury in preeclampsia was decreased, indicating a role for peroxynitrite formation as a mechanism of endothelial cell injury. In conclusion, the modulation of neutrophils causing superoxide production to dominate over nitrite release provides a reasonable explanation for endothelial cell dysfunction in preeclampsia.

Semicarbazide-sensitive amine oxidase in pre-eclampsia: no relation with markers of endothelial cell activation

Background: Semicarbazide sensitive amine-oxidase (SSAO) is an adhesion molecule and thought to play a role in endothelial cell dysfunction (ECD). SSAO has never been associated with markers of ECD. Pre-eclampsia (PE) is, like the early stages of atherosclerosis, characterised by ECD. SSAO could contribute to ECD in PE. Methods: Plasma samples were obtained in 14 pre-eclamptic patients and 14 matched controls. In these SSAO-activity, von Willebrand factor (vWF) levels and ED1 fibronectin levels were determined. Placental tissue was collected of 12 pre-eclamptic pregnancies, 8 preterm deliveries and 12 term controls. In these samples, SSAO activity was assessed. In a subset of these placentas, immunohistochemical staining was performed for SSAO, ICAM-1 and VCAM-1. Results: Plasma SSAO activity was not significantly different between pre-eclamptic subjects and controls. VWF and ED1 fibronectin were both significantly increased in the pre-eclamptic subjects. There was no correlation between SSAO activity and vWF or ED1 fibronectin levels. Placental SSAO activity was not different between pre-eclamptic pregnancies, preterm deliveries and term controls. There was strong staining of SSAO in vascular smooth muscle cells (VSM) and moderate staining of trophoblast in all three groups. Endothelial cell expression of SSAO was only seen in term controls and the placentas of pre-eclamptic patients. There was no association between the expression of SSAO, ICAM-1 or VCAM-1 in the placentas of pre-eclamptic patients. Conclusion: SSAO expression and activity are not related to markers of ECD.

Association of pre-eclampsia with common coding sequence variations in the lipoprotein lipase gene.

Marked dyslipidemia may contribute to endothelial cell dysfunction in pre-eclampsia. Carriers of N291S or D9N missense mutations in the lipoprotein lipase (LPL) gene exhibit reductions in LPL activity and are predisposed to dyslipidemia and cardiovascular disease. In Caucasians, the D9N variant is in strong linkage disequilibrium with the - 93T --> G promoter variant. A fourth LPL variant, S447X, is often associated with a beneficial lipid profile. We asked if the N291S and the combination D9N/- 93T --> G variants are more prevalent, and if the S447X variant is less prevalent, in Caucasian women with pre-eclampsia as compared with normal pregnancies. DNA amplification was followed by an allele-specific oligonucleotide ligation assay. Allele frequencies were analyzed with a chi2 table and Yates' correction. The N291S variant was identified in 11.1% of pre-eclamptics as compared with 2.9% of pregnancy controls (p = 0.008). All carriers of D9N were also carriers of - 93T --> G. The D9N/ - 93T --> G combined variant was found in 7.1% of pre-eclamptics as compared with 1.4% of pregnancy controls (p = 0.02). No individuals were carriers of both N291S and D9N/ - 93T --> G. Thus, 18.2% of pre-eclamptics had either of these LPL mutations compared with 4.3% of pregnancy controls (and 4.4% of population controls). The frequency of the S447X variant did not differ among groups. We conclude that carriers of N291S or combined D9N/ - 93T --> G mutations in the LPL gene are at substantially increased risk of pre-eclampsia.

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 μmol O 2 /min per gram of dry weight) than did exposure to sera of matched pregnant and nonpregnant control subjects (0.34 ± 0.08 μmol O 2 /min per gram of dry weight, P < .001, and 0.29 ± 0.03 μmol O 2 /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. (Am J Obstet Gynecol 1998;179:1534-8.)

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 ( R 2 0.42, p < 0.01) and post partum ( R 2 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 ( R 2 0.38, p < 0.02, in 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. (A M J O BSTET G YNECOL 1996;174:975-82.)

Endothelial dysfunction in preeclampsia. Part II: Reducing the adverse consequences of endothelial cell dysfunction in preeclampsia; therapeutic perspectives.

Next to low-dose Aspirin there appear to be several new and promising pharmacologie approaches for reducing the adverse consequences of endothelial cell dysfunction in preeclampsia. Among these are selective thromboxane-A2 synthetase and/or thromboxane-A2 receptor antagonists, stable prostacyclin analogues, selective S(erotonin)2-receptor blockers, nitrovasodilators, glycoprotein IIb/IIIa antagonists, hirudin, and ticlopidine. Early-onset preeclampsia appears to be associated with certain disorders that are likely to provoke an arterial thrombotic process by impairing the normal endothelial cell-platelet interactions. Especially heterozygous hyperhomocysteinemia, protein S deficiency and anticardiolipin antibodies appear to be fairly common. The management of these 3 separate disease entities will be discussed.

The Role of von Willebrand Factor in Pre-Eclampsia

The von Willebrand factor (vWF) has gained considerable interest in recent years as a marker of endothelial cell activation or insult and by virtue of its interactions with platelets and vessel walls. Altered patterns of vWF multimers were found to occur frequently in patients with thrombotic thrombocytopenic purpura in the acute and chronic stages. This disorder shares some clinical and laboratory findings with pre-eclampsia, including thrombocytopenia. Recent studies have also suggested that abnormalities of endothelial cell metabolism play a central role in the pathophysiology of pre-eclampsia. In order to determine if vWF could be instrumental in the disease process and the thrombocytopenia of pre-eclampsia we analyzed the ante- and postpartum structural and functional distribution of vWF. This data was correlated with hematological parameters such as platelet counts and the clinical severity of the disease. We found no consistent changes of vWF in association with thrombocytopenia or clinical severity. However, functional vWF was lower in postpartum samples of severely affected pre-eclamptics as compared to normal controls. This finding may reflect endothelial cell exhaustion after stimulation or cellular injury. Elevated titers of fibrin split products and thrombocytopenia were evident in severe pre-eclampsia, as seen in DIC, despite factor VIII coagulant levels within the normal range. Our data is consistent with the hypothesis of endothelial cell dysfunction in pre-eclampsia. However, the mechanism of thrombocytopenia in this disorder does not appear to be related to alterations in the structure or biological function of vWF.