Pathophysiology of the clinical manifestations of preeclampsia

Elevation of urinary adipsin in preeclampsia: correlation with urine protein concentration and the potential use for a rapid diagnostic test

Early diagnosis and treatment of preeclampsia are essential for prevention of seizure development and fetus maturation. Although various methods have been developed for predicting or monitoring the onset of preeclampsia, a simple assay that can be used as a home or point of care test remains unavailable. We attempted to find a urinary protein that could be used as a biomarker for developing such a test. Urinary samples were collected from 124 preeclampsia and 135 healthy pregnant women for screening using a protein array technology and quantification by ELISA. A urinary protein, adipsin, was found significantly increased, and the adipsin creatinine ratio was closely correlated with the urinary 24-hour protein in patients with preeclampsia. When combined with the increased diastolic blood pressure (≥90 mm Hg), the sensitivity was 90.3% and the specificity reached 100.0% for preeclampsia diagnosis. We then developed a laminar flow immunoassay for rapid diagnosis, and the sensitivity and specificity were 89.04% and 100%, respectively, when combined with increased diastolic blood pressure. Because of the easiness of sample collection, assay conduction, and result interpretation, this urine test can be potentially used as a home test for monitoring preeclampsia onset for high-risk pregnant women and as a rapid test for a preliminary diagnosis for emergency patients at hospitals.

The heme oxygenases: important regulators of pregnancy and preeclampsia

The heme oxygenase system has long been believed to act largely as a housekeeping unit, converting prooxidant free heme from heme protein degradation into the benign bilirubin for conjugation and safe excretion. In recent decades, however, heme oxygenases have emerged as important regulators of cardiovascular function, largely through the production of their biologically active metabolites: carbon monoxide, bilirubin, and elemental iron. Even more recently, a number of separate lines of evidence have demonstrated an important role for the heme oxygenases in the establishment and maintenance of pregnancy. Early preclinical and clinical studies have associated defects in the heme oxygenase with the obstetrical complication preeclampsia, as well as failure to establish adequate placental blood flow, an underlying mechanism of the disorder. Several recent preclinical studies have suggested, however, that the heme oxygenase system could serve as a valuable therapeutic tool for the management of preeclampsia, which currently has few pharmacological options. This review will summarize the role of heme oxygenases in pregnancy and highlight their potential in advancing the management of patients with preeclampsia.

Risks of gestational diabetes and preeclampsia over the last decade in a cohort of Alberta women

OBJECTIVES

The incidence of gestational diabetes mellitus (GDM) is increasing. However, less is known about the incidence of preeclampsia (PE) and whether it is affected by the presence of GDM. We sought to document the population-level incidence of GDM and PE during the last decade and examine the association between GDM and PE after accounting for established risk factors.

METHODS

We selected a population-based cohort retrospectively using data from the Alberta Perinatal Health Program registry. Logistic regression was used to examine the association between GDM and PE after adjusting for baseline characteristics.

RESULTS

Of 426 296 deliveries between 2000 and 2009, 422 672 were in women without pre-existing diabetes. Among these women, the incidence of GDM increased from 3.1% in 2000 to 4.6% in 2009 (P < 0.01), while the incidence of PE remained stable at approximately 1.3% per year. The incidence of PE was significantly higher in women with GDM than in those without GDM (2.6% vs. 1.2%; P < 0.01). After adjustment, women with GDM had a 90% higher risk of PE than those without GDM (OR 1.9; 95% CI 1.7 to 2.1). Other significant risk factors for PE were age, obesity, nulliparity, multifetal gestation, pre-existing hypertension, and chronic kidney disease.

CONCLUSION

In this contemporary population-based study spanning 10 years, there was a significant increase in the incidence of GDM over time. The higher incidence of PE in women with GDM than in normoglycemic women suggests a need for heightened surveillance and monitoring of women with GDM for the development of PE.

Placental ischemia induces changes in gene expression in chorionic tissue

Preeclampsia is a serious and common hypertensive complication of pregnancy, affecting ~5 to 8 % of pregnancies. The underlying cause of preeclampsia is believed to be placental ischemia, which causes secretion of pathogenic factors into the maternal circulation. While a number of these factors have been identified, it is likely that others remain to be elucidated. Here, we have utilized a relevant preclinical rodent model of placental ischemia-induced hypertension, the reduced uterine perfusion pressure (RUPP) model, to determine the effect of chronic placental ischemia on the underlying chorionic tissue and placental villi. Tissue from control and RUPP rats were isolated on gestational day 19 and mRNA from these tissues was subjected to microarray analysis to determine differential gene expression. At a statistical cutoff of p < 0.05, some 2,557 genes were differentially regulated between the two groups. Interestingly, only a small subset (22) of these genes exhibited changes of greater than 50 % versus control, a large proportion of which were subsequently confirmed using qRT-PCR analysis. Network analysis indicated a strong effect on inflammatory pathways, including those involving NF-κB and inflammatory cytokines. Of the most differentially expressed genes, the predominant gene classes were extracellular remodeling proteins, pro-inflammatory proteins, and a coordinated upregulation of the prolactin genes. The functional implications of these novel factors are discussed.

Clinical syndromes associated with acquired antithrombin deficiency via microvascular leakage and the related risk of thrombosis

Antithrombin (AT) is a 65kDa glycoprotein belonging to a group of inhibitory factors known as serpins (serine protease inhibitors). It plays a critical role in the inhibition of coagulation and inflammation processes within the environment of the vascular endothelium. Inadequate levels of functional AT in plasma results in an increased risk of thrombotic events, both venous and arterial. AT deficiency can be inherited or acquired. Congenital AT deficiency is the most severe inherited thrombophilic condition with an odds ratio of 20 for the increased risk of venous thrombosis. Acquired AT deficiency occurs in a variety of physiologic and pathologic medical conditions with similar risks of increased thrombosis. In this article, we review clinical settings characterized by an acquired AT deficiency largely or partly subsequent to protein microvascular leakage. Other different mechanisms of AT depletion are implied in some clinical conditions together with endothelial loss, and, therefore, outlined. In addition, we provide a description of the current knowledge on the specific mechanisms underlying endothelial AT leakage and on the consequences of this protein decrease, specifically looking at thrombosis. We identify potential directions of research that might prove useful in patients with acquired AT deficiency.

Recent insights into the pathophysiology of preeclampsia

Preeclampsia, characterized by new-onset gestational hypertension and proteinuria, is a common and serious complication of pregnancy. Evidence from both animal and human studies has implicated placental ischemia and hypoxia as a central causative factor in the etiology of the disorder. The ischemic placenta in turn initiates a cascade of secondary effector mechanisms, including altered proangiogenic and antiangiogenic factor balance, increase in maternal oxidative stress and endothelial and immunological dysfunction. The full elucidation of these mechanisms will hopefully lead to a more complete understanding of the etiology of preeclampsia and lead to successful therapeutic intervention through the targeted disruption of new and novel pathways.

Gestational diabetes and hypertensive disorders of pregnancy as vascular risk signals: an overview and grading of the evidence

The occurrence of common pregnancy-related medical disorders identifies women at high risk of developing future vascular disease. Systematic reviews of cohort studies demonstrate that gestational diabetes confers a 7-fold risk increase for type 2 diabetes, and preeclampsia confers a 1.8-fold risk increase for type 2 diabetes and 3.4-fold risk increase for hypertension. Gestational diabetes and hypertensive disorders of pregnancy (HDP) increase the risk of premature vascular disease, but the 2-fold risk increase associated with preeclampsia is only partially explained by the development of traditional vascular risk factors. Despite the compelling evidence for gestational diabetes and HDP as vascular risk indicators, there are no published Canadian vascular prevention guidelines that recognize these postpartum women. In contrast, the 2011 American Heart Association guidelines on cardiovascular disease in women include gestational diabetes and HDP in their vascular risk assessment. Studies indicate that the importance surveillance of vascular risk factors in these women after pregnancy is underappreciated by the women themselves and their physicians. Although a prudent diet and physically active lifestyle were demonstrated to reduce diabetes risk in women with a gestational diabetes history in the American Diabetes Prevention Program trial, adoption of these health behaviours is low; qualitative studies confirm a need for tailored strategies that address barriers and provide social support. Further research is also needed on approaches to reduce vascular risk in women with a history of gestational diabetes and HDP. Otherwise, an early window of opportunity for chronic disease prevention in young, high-risk women will be missed.

Urinary neutrophil gelatinase-associated lipocalin (NGAL) excretion increases in normal pregnancy but not in preeclampsia

Neutrophil gelatinase-associated lipocalin (NGAL) serum values have been shown to increase in preeclampsia. The goal of the present study was to evaluate changes in urinary NGAL concentrations during uncomplicated pregnancy and in cases of preeclampsia and hypertension.

Fifty-one pregnant women who developed preeclampsia and 28 diagnosed with essential or gestational hypertension were investigated for urinary NGAL concentrations during pregnancy. As controls, 100 healthy pregnant women with uncomplicated singleton pregnancies were randomly selected. Urinary NGAL as well as urinary creatinine and albumin were measured by a standardized clinical chemistry platform (ARCHITECT

Urinary NGAL concentrations increased during pregnancy in healthy pregnant women, whereas this increase was not detected in preeclampsia. In order to correct for diuresis, spot urine concentrations were also determined as NGAL/creatinine ratio. NGAL/creatinine ratio in pregnancy week 36–38 was significantly lower in preeclampsia than in healthy pregnant women or pregnant women with hypertension. NGAL urinary concentrations did not correlate with albumin concentration in urine.

Urinary NGAL is not a valuable early biomarker for preeclampsia.

Matrix metalloproteinases as drug targets in preeclampsia

Preeclampsia is an important syndrome complicating pregnancy. While the pathogenesis of preeclampsia is not entirely known, poor placental perfusion leading to widespread maternal endothelial dysfunction is accepted as a major mechanism. It has been suggested that altered placental expression of matrix metalloproteinases (MMPs) may cause shallow cytotrophoblastic invasion and incomplete remodeling of the spiral arteries. MMPs are also thought to link placental ischemia to the cardiovascular alterations of preeclampsia. In fact, MMPs may promote vasoconstriction and surface receptors cleavage affecting the vasculature. Therefore, the overall goal of this review article is to provide an overview of the pathophisiology of preeclampsia, more specifically regarding the role of MMPs in the pathogenesis of preeclampsia and the potential of MMP inhibitors as therapeutic options.

Soluble fms-like tyrosine kinase-1 and soluble endoglin in HIV-associated preeclampsia

OBJECTIVE

Preeclampsia is characterized by endothelial dysfunction combined with increased concentrations of sFlt1, which antagonizes the biological effects of VEGF and PlGF, and of sEng, which antagonizes TGFβ1. This angiogenic imbalance may have a role in its etiology. This study evaluated the expression of VEGF, PlGF, sFlt1 and sEng amongst third trimester pregnancies in women with HIV-associated pre-eclampsia.

METHOD

Serum and placental tissue were obtained from 76 pregnancies in women who were normotensive and HIV negative (N-) or positive (N+), and in women who were pre-eclamptic and HIV negative (P-) or positive (P+). The serum and placental samples were quantitatively evaluated using ELISAs and RT-PCR respectively.

RESULTS

Placental sFlt1 expression differed significantly between the N- and P- groups (p=0.001). Similarly, sEng expression differed between the N- and P- groups (p=0.001). No significant effect was shown between HIV status and pregnancy. Serum sFlt1 (p=0.02) and sEng (p=0.001) were up-regulated in the P- compared to the N- groups. Similarly, no significant effect was shown between HIV status and pregnancy. Both VEGF and PlGF did not differ significantly between groups. Notably, sEng expression was elevated in both placenta and serum, whilst placental sFlt1 differed from serum. A weak but significant correlation between serum and placental concentration for sFlt1, sEng and PlGF (r=0.26, p=0.031; r=0.42, p<0.001 and r=-0.3, p=0.014) was observed.

CONCLUSIONS

This novel study demonstrates an up-regulation of serum sFlt1 and sEng in preeclamptic compared to normotensive groups irrespective of the HIV status of the pregnancy. This implicates a contributory role of sFlt1 and sEng in preeclampsia development. The serum reduction of sFlt1 and sEng within the HIV positive compared to HIV negative cohorts may imply a neutralization of the immune hyperreactivity of preeclampsia.

Impaired renal function and increased urinary isoprostane excretion in Ghanaian women with pre-eclampsia

Background

The cause of pre-eclampsia remains largely unknown, but oxidative stress (an imbalance favoring oxidant over antioxidant forces) has been implicated in contributing to the clinical symptoms of hypertension and proteinuria. Assessment of oxidative stress in pre-eclampsia using urinary isoprostane has produced conflicting results, and it is likely that renal function may affect isoprostane excretion. The aim of this study was to determine the role of oxidative stress in the pathophysiology of pre-eclampsia and to assess the effect of renal function on isoprostane excretion in pre-eclampsia in the Ghanaian population.

Methods

This was a case-controlled study, comprising 103 pre-eclamptic women and 107 normal pregnant controls and conducted at the Korle-Bu Teaching Hospital between December 2006 and May 2007. The study participants were enrolled in the study after meeting the inclusion criteria and signing their written informed consent. Oxidative stress was determined by measuring urinary excretion of isoprostane and total antioxidant capacity using an enzyme-linked immunosorbent assay technique. Renal function was assessed by calculating the estimated glomerular filtration rate using the Modification of Diet in Renal Disease formula.

Results

The pre-eclampsia group had significantly (P = 0.0006) higher urinary isoprostane excretion (2.81 ± 0.14 ng/mg creatinine) than the control group (2.01 ± 0.18 ng/mg creatinine) and a significantly (P = 0.0008) lower total antioxidant power (1.68 ± 0.05 mM) than the control group (1.89 ± 0.04 mM). Urinary isoprostane excretion showed a positive correlation with both mean arterial pressure (r = 0.261) and microalbuminuria (r = 0.510) in the pre-eclampsia cases. The pre-eclampsia group had a significantly lower estimated glomerular filtration rate than the control group (P < 0.001), indicating more renal impairment.

Conclusion

The increased urinary excretion of isoprostanes and decreased total antioxidant power in the in pre-eclampsia group suggest increased production of oxidants and depletion and/or reduction of maternal antioxidants. Increased oxidative stress may be important in the pathophysiology of pre-eclampsia by contributing to endothelial dysfunction, proteinuria, and hypertension.

From preeclampsia to renal disease: a role of angiogenic factors and the renin-angiotensin aldosterone system?

Complicating up to 8% of pregnancies, preeclampsia is the most common glomerular disease worldwide and remains a leading cause of infant and maternal morbidity and mortality. Although the exact pathogenesis of this syndrome of hypertension and proteinuria is still incomplete, a consistent line of evidence has identified an imbalance of proangiogenic and anti-angiogenic proteins as a key factor in the development of preeclampsia. Furthermore, more attention has been recently addressed to the renin-angiotensin aldosterone system (RAAS), to provide understanding on the hypertension of preeclampsia. The imbalance of the RAAS and the imbalance between angiogenic and anti-angiogenic factors, which may be both common to preeclampsia and chronic kidney disease (CKD), might explain why a history of preeclampsia predisposes women to develop CKD. In this review, we briefly describe the characteristics of preeclampsia with a focus on the mechanisms of angiogenesis and the RAAS and its role in the pathogenesis of preeclampsia. Our main focus will be on the intriguing association between preeclampsia and the subsequent increased risk of developing CKD and on the potential mechanisms by which the risk of CKD is elevated in women with a history of preeclampsia.

Kidney biopsy in pregnancy: evidence for counselling? A systematic narrative review

BACKGROUND

Kidney diseases, which have a prevalence of 3% in women of childbearing age, are increasingly encountered in pregnancy. Glomerulonephritis may develop or flare up in pregnancy, and a differential diagnosis with pre-eclampsia may be impossible on clinical grounds. Use of kidney biopsy is controversial, but a systematic review has not been carried out to date.

OBJECTIVES

To review the literature on kidney biopsy in pregnancy, with a focus on indications, risks and timing.

SEARCH STRATEGY

Medline, Embase, CHINAL and the Cochrane Library were searched in September 2012, with 'pregnancy' and 'kidney biopsy' used as MESH and free terms, for the period 1980-2012. Results were filtered for 'human' if this option was available.

SELECTION CRITERIA

Biopsies during pregnancy and within 2 months after delivery. Case reports (fewer than five cases) and kidney grafts were excluded. Paper selection was performed in duplicate.

DATA COLLECTION AND ANALYSIS

Data were extracted in duplicate. The high heterogeneity in study design necessitated that the review be narrative, except for data on adverse events, which were analysed with regard to the timing of kidney biopsy.

MAIN RESULTS

Of 949 references, 39 were selected, providing data on 243 biopsies in pregnancy and 1236 after delivery (timing was unclear in 106 women). The main aims of the studies were to define morphology in pre-eclampsia (23 studies), to carry out a risk-benefit analysis of kidney biopsy (11 studies), and to investigate pregnancy-related acute kidney injury (five studies). Four cases of major bleeding complications occurred at 23-26 weeks of gestation. Relevant complications were observed in 7% of women during pregnancy and 1% after delivery (P = 0.001). Kidney biopsy performed for the diagnosis of glomerulonephritis or pre-eclampsia led to therapeutic changes in 66% of cases.

AUTHORS' CONCLUSIONS

The evidence on kidney biopsy in pregnancy is heterogeneous, but a significantly higher risk of complications (relative to postpartum biopsy) was found, with a possible peak at around 25 gestational weeks.

Maternal and pregnancy-related death: causes and frequencies in an autopsy study population

BACKGROUND

Maternal deaths during pregnancy, both from pregnancy-related or other causes, are rare in Western industrialized countries. In this study we report maternal and pregnancy-related deaths in a large autopsy population focusing on medical history, autopsy findings and histological examinations.

MATERIALS AND METHODS

Medico-legal autopsy files (n = 11,270) from the Institute of Legal Medicine and Forensic Sciences, University Medical Centre Charité, University of Berlin, and the State Institute of Legal and Social Medicine, Berlin, from 2005 to 2010 were reviewed. All female cases between 15 and 49 years were checked for maternal and pregnancy-related death, and deaths of pregnant women from non-natural causes were also included. Fatalities that met the chosen criteria were classified as "direct gestational death," "indirect gestational death" or "non-gestational death."

RESULTS

13 female fatalities (0.12 %) met the chosen criteria (median age 28 years ± 6.87 SD). Eight (61.5 %) women died in-hospital, four (30.8 %) at home, and one woman died in public. Three cases (23.1 %) were "non-gestational deaths," and one case (7.7 %) remained unclear after autopsy and additional examinations. Of the remaining nine cases, six cases (46.5 %) were "direct gestational deaths," and two cases (15.4 %) were "indirect gestational deaths." One case (7.7 %) was not to be defined as "late maternal death," but the cause of death seemed to be directly related to previous gestation ["(very) late maternal death"].

CONCLUSION

Maternal deaths during pregnancy, both from pregnancy-related or other causes, remain an uncommon event in routine forensic autopsy practice. We report on the collection and analysis of maternal and pregnancy-related deaths in a large autopsy population, with particular attention to the phenomenology of pregnancy, pathophysiological changes in different organ systems and their detection, and the forensic autopsy assessment.

Preeclampsia - Aetiology, Current Diagnostics and Clinical Management, New Therapy Options and Future Perspectives

Preeclampsia is a multisystem disease for which the exact causes have not yet been sufficiently clarified. However, in the past few years it has become clear that a placental imbalance between angiogenic and anti-angiogenic proteins is the decisive pathogenetic factor for the occurrence of preeclampsia. With the possibility to measure these angiogenic factors (sFlt-1/PlGF ratio) in maternal blood full new diagnostic possibilities have been opened that enable the certain diagnosis or exclusion of the diseases as well as a short-term prognosis to be made. In secondary prevention the current data situation for ASA confirms a moderate but measurable utility. The management concept depends on gestational age. In the case of early clinical manifestations (< 34th week of pregnancy) the clinical management in a perinatal centre remains unchanged with foeto-maternal monitoring and induction of pulmonary maturation, symptomatic therapy under careful blood pressure lowering and determination of the optimal delivery time. A balance must be made here between foetal immaturity and maternal risks upon prolongations. The pathomechanism of anti-angiogenic overload with sFlt-1 provides a starting point for first therapeutic interventions. The present article gives an overview of current diagnostic options and presents possible future therapeutic perspectives for discussion.

Endothelial FOS expression and pre-eclampsia

OBJECTIVE

To study gene expression profiles in human endothelial cells incubated with plasma from women who developed pre-eclampsia and women with normotensive pregnancies.

DESIGN

A case-control study.

SETTING

A longitudinal nested case-control study within three maternity units.

POPULATION

A mixed obstetric population attending maternity hospitals in Glasgow.

METHODS

Plasma was obtained at both 16 and 28 weeks of gestation from 12 women: six women subsequently developed pre-eclampsia (cases) and six women, matched for age, body mass index (BMI) and parity, remained normotensive (controls). Human umbilical vein endothelial cells (HUVECs) were incubated with plasma for 24 hour before RNA isolation.

MAIN OUTCOME MEASURES

Gene expression profiles were compared between the two gestational time points using Illumina(®) HumanHT-12 v4 Expression BeadChips. Differential mRNA expression observed in microarray experiments were validated using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR), and gene networks were analysed using Ingenuity(®) pathway analysis.

RESULTS

There was a significant difference in the expression of 25 genes following incubation with plasma from controls, and an increase in the expression of 11 genes following incubation with plasma from cases, with no overlap between the two groups (false discovery rate, FDR < 0.05). There was a 3.74-fold (FDR < 0.001) increase in the expression of the c-Fos gene (FOS) when HUVECs were incubated with control plasma from 16 and 28 weeks of gestation, with no significant difference between the two time points with plasma from cases. Similar findings for FOS were obtained by qRT-PCR.

CONCLUSIONS

Plasma from women who subsequently develop pre-eclampsia appears to contain factors that lead to the dysregulation of FOS in endothelial cells during pregnancy. Reduced expression of c-Fos may lead to impaired vasculogenesis, and thereby contribute to the development of pre-eclampsia.

Hypertension in pregnancy

Hypertension complicates 5% to 7% of all pregnancies. A subset of preeclampsia, characterized by new-onset hypertension, proteinuria, and multisystem involvement, is responsible for substantial maternal and fetal morbidity and is a marker for future cardiac and metabolic disease. This American Society of Hypertension (ASH) position paper summarizes the clinical spectrum of hypertension in pregnancy, focusing on preeclampsia. Recent research breakthroughs relating to etiology are briefly reviewed. Topics include classification of the different forms of hypertension during pregnancy, and status of the tests available to predict preeclampsia, and strategies to prevent preeclampsia and to manage this serious disease. The use of antihypertensive drugs in pregnancy, and the prevention and treatment of the convulsive phase of preeclampsia, eclampsia, with intravenous MgSO(4) is also highlighted. Of special note, this guideline article, specifically requested, reviewed, and accepted by ASH, includes solicited review advice from the American College of Obstetricians and Gynecologists.

Effects of angiogenic factors, antagonists, and podocyte injury on development of proteinuria in preeclampsia

Proteinuria is universal to all patients with preeclampsia. We examined the urinary podocytes in women with preeclampsia (n = 14), gestational hypertension (n = 14), and normal pregnancy. Maternal serum and urinary concentrations of vascular endothelial growth factor (VEGF), placental growth factor (PlGF), and the antiangiogenic factor soluble fms-like tyrosine kinase 1 (sFlt-1) were detected. These concentrations were used to evaluate the urinary excretion of podocytes and the alteration of angiogenic factors and to assess their relationships to proteinuria in preeclampsia. Our studies suggest that the urinary podocyte number and angiogenic factors are correlated with random urine albumin/creatinine ratio and blood pressure. Receiver-operating characteristic (ROC) curves of serum and urinary PlGF and the PlGF/sFlt-1 ratio as well as the presence of podocyturia confirmed their usefulness in distinguishing preeclamptic and normotensive pregnant women. In addition, combinations of serum or urinary PlGF or podocyturia tests in parallel or in series provided the best clue for identifying patients with preeclampsia. We considered that the dysregulation of angiogenic factors and its subsequent podocyte injury may contribute to the mechanism of proteinuria development in preeclampsia.

Maternal exposure to moderate ambient carbon monoxide is associated with decreased risk of preeclampsia

OBJECTIVE

Carbon monoxide (CO) in cigarette smoke may be the mechanism by which tobacco use during pregnancy decreases the risk of the development of preeclampsia. We attempted to test this hypothesis by examining the effect of maternal exposure to ambient CO on preeclampsia.

STUDY DESIGN

Births that occurred between 2004 and 2009 in the Canadian province of Ontario were extracted from the data. Study subjects were divided into 4 groups according to quartiles of CO concentration that were based on maternal residence. Adjusted odds ratio and 95% confidence interval were used to estimate the independent effect of CO on preeclampsia.

RESULTS

Rates of preeclampsia were 2.32%, 1.97%, 1.59%, and 1.26%, respectively, in the first, second, third, and fourth quartile of CO concentration. The inverse association between CO concentration and preeclampsia risk remained the same after adjustment for several important confounding factors.

CONCLUSION

Maternal exposure to moderate ambient CO is associated independently with a decreased risk of preeclampsia.

FOLATE METABOLISM AND PREECLAMPSIA

Preeclampsia (PE) is a multisystem disorder of human pregnancy, affecting about 6% of all pregnancies worldwide, and is one of the leading causes of maternal and infant morbidity and mortality. Despite decades of research into the pathogenesis of this complex disease, the underlying mechanisms remain unclear. As a result, the options for prevention and management of PE are limited. In recent years, there has been a growing body of evidence suggesting that folate deficiency is associated with PE, and folic acid supplementation may reduce the risk of developing PE in certain populations. Folate contributes to cell division and growth, and folate metabolism is involved in a large number of physiological and pathophysiological processes in human development. Sufficient supply of folate is therefore particularly important during pregnancy. Nevertheless, the exact mechanisms of folic acid deficiency increasing the risk of developing PE are still unclear. This article reviews what is understood about the aetiology of PE and the relationship between folate metabolism and PE so as to enhance further discussions on the subject.

A successful term pregnancy using in-center intensive quotidian hemodialysis

A 30-year-old woman with stage V chronic kidney disease presented at 7 weeks gestation. She had no uremic symptoms; however, blood urea nitrogen (BUN) was 33.6 mg/dL. Because of the well-established negative relationship between BUN and fetal outcomes, dialysis was initiated with a nocturnal home hemodialysis (NHD)-like prescription performed in-center for logistical reasons. She received 36 hours per week of dialysis. Following the initiation of renal replacement therapy, the predialysis BUN was within the normal physiologic range. The patient had an uncomplicated pregnancy with delivery of a healthy 3000 g infant at 39 weeks gestation. This case adds to the growing literature that supports more intensive dialysis in the pregnant women than was previously recommended. This dose of dialysis should be offered to women in an in-center setting if nocturnal home hemodialysis is not available or feasible.

Endothelin as a final common pathway in the pathophysiology of preeclampsia: therapeutic implications

PURPOSE OF REVIEW

Preeclampsia remains a major health concern in the United States and worldwide. Recent research has begun to shed light on the underlying mechanisms responsible for the symptoms of preeclampsia, and may provide new avenues for therapy for the preeclamptic patient.

RECENT FINDINGS

The central role of placental ischemia in the manifestation of preeclampsia has provided new understanding for the origin of pathogenic factors in the preeclamptic patient. The release of soluble factors into the maternal bloodstream from the ischemic placenta is now recognized as a central mechanism in disease manifestation. Specifically, the importance of the vascular endothelial growth factor antagonist soluble fms-like tyrosine kinase and immune factors as factors regulating maternal endothelial dysfunction has become widely acknowledged. Furthermore, mounting evidence implicates the signaling protein endothelin-1 as the final converging factor in the multifaceted cascades that are responsible for the symptomatic manifestation of preeclampsia. Endothelin-1, as a final common pathway in the pathogenic cascade of preeclampsia, presents an intriguing new therapeutic approach for preeclamptic patients.

SUMMARY

Identification of antiangiogenic, autoimmune, and inflammatory factors produced in response to placental ischemia have provided potential new avenues for future research into novel therapies for the preeclamptic patient, and suggest new therapeutic avenues for the treatment of preeclampsia.

A model of preeclampsia in rats: the reduced uterine perfusion pressure (RUPP) model

Preeclampsia is defined as new-onset hypertension with proteinuria after 20 wk gestation and is hypothesized to be due to shallow trophoblast invasion in the spiral arteries thus resulting in progressive placental ischemia as the fetus grows. Many animal models have been developed that mimic changes in maternal circulation or immune function associated with preeclampsia. The model of reduced uterine perfusion pressure in pregnant rats closely mimics the hypertension, immune system abnormalities, systemic and renal vasoconstriction, and oxidative stress in the mother, and intrauterine growth restriction found in the offspring. The model has been successfully used in many species; however, rat and primate are the most consistent in comparison of characteristics with human preeclampsia. The model suffers, however, from lack of the ability to study the mechanisms responsible for abnormal placentation that ultimately leads to placental ischemia. Despite this limitation, the model is excellent for studying the consequences of reduced uterine blood flow as it mimics many of the salient features of preeclampsia during the last weeks of gestation in humans. This review discusses these features.

Postpartum amaurosis in a woman with severe preeclampsia

The maternal and perinatal fetal prognosis of preeclampsia depends on the gestational age of the fetus at onset, the severity of the disease, the quality of care, and the presence of pre-existent medical conditions. One of the uncommon effects of severe preeclampsia on the eye is sudden loss of vision. The present case report is of a woman with severe preeclampsia exacerbated by delivery that coursed with difficult-to-control arterial hypertension and reversible cortical amaurosis without impaired consciousness or seizures.

Induction of heme oxygenase-1 shifts the balance from proinjury to prosurvival in the placentas of pregnant rats with reduced uterine perfusion pressure

Placental hypoxia/ischemia has been implicated as a central factor in the development of preeclampsia. One particularly useful animal model to study the impact of placental ischemia is the reduced uterine perfusion pressure (RUPP) model. We have previously demonstrated that RUPP animals exhibit elevated placental oxidative stress, which plays an important role in the development of the associated maternal hypertension. Recently, we have demonstrated that cobalt protoporphyrin (CoPP)-mediated induction of heme oxygenase-1 (HO-1) attenuates RUPP-induced oxidative stress and consequent hypertension. However, signaling pathways that are involved in this process are virtually unknown. Here, we show that placentas from RUPP animals exhibit increased phosphorylation of JNK, STAT1, STAT3, and p52shc with a concomitant increase in caspase-3 activation and depletion of intracellular ATP. Treatment with CoPP decreased RUPP-induced phosphorylation of JNK and STAT1, while it increased phosphorylation of ERK and STAT3, leading to decreased caspase-3 activation and restoration of intracellular ATP content. Our data imply that RUPP induces oxidative stress and the consequent injurious state by increasing phosphorylation of mediators of injury (STAT1, JNK) and, to a lesser extent, survival (STAT3, p52shc) in placentas of pregnant rats. HO-1 induction shifts this balance to a prosurvival phenotype by augmenting phosphorylation of the prosurvival ERK and STAT3, while suppressing phosphorylation of JNK and STAT1. This attenuates the resulting injury, as indicated by caspase-3 activation and ATP depletion. These results demonstrate a novel therapeutic activity of HO-1 induction in placental cell survival during ischemia and support the HO-1 pathway as a promising therapeutic target for the management of preeclampsia.

Renal evaluation in women with preeclampsia

BACKGROUND/AIMS

Preeclampsia (PE) is a cause of glomerulopathy worldwide. Urinary retinol-binding protein (RBP) is a marker of proximal tubular dysfunction, albuminuria is an endothelial injury marker, urine protein:creatinine ratio (PCR) may have a predictive value for renal disease later in life, and, recently, podocyturia has been proposed as a sensitive tool in pregnancy, but it needs to be tested. The aim of this study was to evaluate renal involvement in PE and healthy pregnancy.

METHODS

Case-control study with 39 pregnant women assessed after 20 weeks of gestation (25 in the control group, CG, and 14 in the PE group) by performing urinary tests.

RESULTS

Mean (±SD) age and gestational age of the CG were 26.9 ± 6.4 years and 37.1 ± 5.0 weeks, and of the PE group 26.4 ± 6.9 years and 30.6 ± 5.6 weeks, respectively (p = 0.001). Mean (±SD) urinary RBP (p = 0.017), albuminuria (p = 0.002), and urinary albumin concentration (UAC) ratio (p = 0.006) of the CG were 0.4 ± 0.7 mg/l, 7.3 ± 6.9 mg/l, and 8.2 ± 6.7 mg/g and of the PE group 2.0 ± 4.4 mg/l, 2,267.4 ± 2,130.8 mg/l (p = 0.002), and 3,778.9 ± 4,296.6 mg/g (p = 0.006), respectively. Mean (±SD) urine PCR in the PE group was 6.7 ± 6.1 g/g (p < 0.001). No statistical differences were found between podocyturia in the CG and PE group (p = 0.258).

CONCLUSIONS

Urinary RBP, PCR, albuminuria, and UAC ratio were elevated in the PE group in comparison to the CG. Podocyturia did not predict PE.

Endothelin: key mediator of hypertension in preeclampsia

Preeclampsia is a pregnancy-induced hypertensive disorder characterized by proteinuria and widespread maternal endothelial dysfunction. It remains one of the most common disorders in pregnancy and remains one of the leading causes of maternal and fetal morbidity. Recent research has revealed that placental insufficiency, resulting in hypoxia and ischemia, is a central causative pathway in the development of the disorder. In response, the placenta secretes soluble substances into the maternal circulation which are responsible for the symptomatic phase of the disease. Among the most well characterized factors in the disease pathology are the anti-angiogenic protein soluble fms-like tyrosine kinase-1 (sFlt-1), inflammatory cytokines, and agonistic angiotensin II type-1 receptor autoantibodies. Each of these factors has been shown to induce hypertension experimentally through the production of endothelin-1 (ET-1), a powerful vasoconstrictor. Antagonism of the endothelin-A receptor has proved beneficial in numerous animal models of gestational hypertension, and it remains an intriguing target for pharmacological intervention in preeclampsia.

Comparative expression profiles for KiSS-1 and REN genes in preeclamptic and healthy placental tissues

OBJECTIVE

The aim of the present work was to look at differences in the placental tissue expression of KiSS-1 and REN genes from preeclamptic and healthy pregnant women, that could account for a possible synergistic function for both genes in the pathogenesis of preeclampsia.

STUDY DESIGN

This case-control study involved 27 preeclamptic women and 27 normoevolutive pregnant women. cDNA was obtained from placental tissue to carry out qPCR for both KiSS-1 and REN genes in order to compare mRNA expression levels in the studied groups. Statistical analysis showed expression differences that correlate with clinical and/or biochemical variables.

RESULTS

Higher expression for KiSS-1 in PEE vs. control woman (p=0.001) was observed, whereas no difference was observed for REN expression (p=0.300) when all the subjects were included. However, REN expression was significant higher when the samples were stratified according to preeclampsia severity. For 18 mild preeclamptic patients the p-value was p=0.001 compared to their controls, while for the remaining nine with severe preeclampsia the expression became significant (p=0.001).

CONCLUSION

Our results suggest that the high KiSS-1 expression seen in preeclamptic patients is in accordance with its role as an inhibitor of trophoblast invasiveness and maintained until the end of gestation. On the other hand, aggressive therapeutic management and/or severity status of patients have a direct effect on placental REN expression levels, masking the natural high expression of this gene on preeclamptic placental tissue. Therefore it was not possible to establish a real concordant expression profile for KiSS-1 and REN genes.

Potential role of intermedin/adrenomedullin 2 in early embryonic development in rats

Adrenomedullin2 (ADM2), also referred to as Intermedin (IMD) is expressed in trophoblast cells in human placenta and enhances the invasion and migration of first trimester HTR-8/SV-neo cells. Recently we demonstrated that infusion of IMD antagonist in pregnant rats causes feto-placental growth restriction suggesting a role for IMD in maintaining a successful pregnancy. Therefore, this study was undertaken to assess if IMD has a functional role in embryo implantation in a rat model. We show that IMD mRNA is expressed in rat implantation sites and its expression is significantly higher on day 15 in placenta compared to days 18-22. Infusion of IMD antagonist IMD₁₇₋₄₇ from day 3 of pregnancy causes a significant decrease in the weights of day 9 implantation sites as well as serum levels of 17β-estradiol, progesterone, nitric oxide and serum MMP2 and MMP9 gelatinase activity. Further, expression of MMP2, MMP9, VEGF and PLGF protein levels are significantly downregulated in the implantation sites of IMD antagonist treated rats. This study suggests a potential involvement of IMD in regulating the factors that are critical for implantation and growth of the embryo and thus in establishment of normal rat pregnancy.

Detection of global DNA methylation and paternally imprinted H19 gene methylation in preeclamptic placentas

Preeclampsia (PE) is a severe hypertensive disorder associated with pregnancy; despite substantial research effort in the past several years, the etiology of PE is still unclear. The role of epigenetic factors in the etiology of PE, including DNA methylation, has been poorly characterized. In the present study, we investigated global DNA methylation as well as DNA methylation of the paternally imprinted H19 gene in preeclamptic placentas. Using 5-methylcytosine immunohistochemistry and Alu and LINE-1 repeat pyrosequencing, we found that the global DNA methylation level and the DNA (cytosine-5) methyltransferase 1 mRNA level were significantly higher in the early-onset preeclamptic placentas when compared with the normal controls. Data from methylation-sensitive high resolution melting demonstrated hypermethylation of the promoter region of the H19 gene, and results of real-time PCR showed decreased mRNA expression of H19 gene in the early-onset preeclamptic placentas as compared with the normal controls. Our results suggest that abnormal DNA methylation during placentation might be involved in the pathophysiology of PE, especially early-onset preeclampsia.

A historical overview of preeclampsia-eclampsia

Preeclampsia is a hypertensive, multisystem disorder of pregnancy whose etiology remains unknown. Although management is evidence-based, preventative measures/screening tools are lacking, treatment remains symptomatic, and delivery remains the only cure. Past hypotheses/scientific contributions have influenced current understanding of preeclampsia pathophysiology and guided management strategies and classification criteria. To provide insight into how past hypotheses/scientific contributions have shaped current practice trends, this article provides a historical overview of preeclampsia-eclampsia.

Increased expression of matrix metalloproteinase-1 in systemic vessels of preeclamptic women: a critical mediator of vascular dysfunction

This study was conducted to determine the following: (1) whether matrix metalloproteinase-1 (MMP-1) is increased in systemic vessels of preeclamptic women, (2) whether this increase might be mediated by neutrophils, and (3) whether MMP-1 could be responsible for vascular dysfunction. Omental arteries and plasma were collected from healthy pregnant and preeclamptic women. Omental arteries were evaluated for gene and protein expression of MMP-1, collagen type 1α, tissue inhibitor of metalloproteinase-1, and vascular reactivity to MMP-1. Gene and protein expression levels were also evaluated in human vascular smooth muscle cells (VSMCs) co-cultured with activated neutrophils, reactive oxygen species, or tumor necrosis factor α. Vessel expression of MMP-1 and circulating MMP-1 levels were increased in preeclamptic women, whereas vascular expression of collagen or tissue inhibitor of metalloproteinase-1 were down-regulated or unchanged. In cultured VSMCs, the imbalance in collagen-regulating genes of preeclamptic vessels was reproduced by treatment with neutrophils, tumor necrosis factor α, or reactive oxygen species. Chemotaxis studies with cultured cells revealed that MMP-1 promoted recruitment of neutrophils via vascular smooth muscle release of interleukin-8. Furthermore, MMP-1 induced vasoconstriction via protease-activated receptor-1, whose expression was significantly increased in omental arteries of preeclamptic women and in VSMCs co-cultured with neutrophils. Collectively, these findings disclose a novel role for MMP-1 as a mediator of vasoconstriction and vascular dysfunction in preeclampsia.

Hypertension in special populations: chronic kidney disease, organ transplant recipients, pregnancy, autonomic dysfunction, racial and ethnic populations

The benefits of appropriate blood pressure (BP) control include reductions in proteinuria and possibly a slowing of the progressive loss of kidney function. Overall, medication therapy to lower BP during pregnancy should be used mainly for maternal safety because of the lack of data to support an improvement in fetal outcome. The major goal of hypertension treatment in those with baroreceptor dysfunction is to avoid the precipitous, severe BP elevations that characteristically occur during emotional stimulation. The treatment of hypertension in African Americans optimally consists of comprehensive lifestyle modifications along with pharmacologic treatments, most often with combination, not single-drug, therapy.