Immunological aspects of pre-eclampsia

Placental Senescence and the Two-Stage Model of Preeclampsia

In this review, we summarize how an increasingly stressed and aging placenta contributes to the maternal clinical signs of preeclampsia, a potentially lethal pregnancy complication. The pathophysiology of preeclampsia has been conceptualized in the two-stage model. Originally, highlighting the importance of poor placentation for early-onset preeclampsia, the revised two-stage model explains late-onset preeclampsia as well, which is often preceded by normal placentation. We discuss how cellular senescence in the placenta may fit with the framework of the revised two-stage model of preeclampsia pathophysiology and summarize potential cellular and molecular mechanisms, including effects on placental and maternal endothelial function. Cellular senescence may occur in response to inflammatory processes and oxidative, mitochondrial, or endoplasmic reticulum stress and chronic stress induce accelerated, premature placental senescence. In preeclampsia, both circulating and tissue-based senescence markers are present. We suggest that aspirin prophylaxis, commonly recommended from the first trimester onward for women at risk of preeclampsia, may affect placentation and possibly mechanisms of placental senescence, thus attenuating the risk of preeclampsia developing clinically. We propose that biomarkers of placental dysfunction and senescence may contribute to altered preventive strategies, including discontinuation of aspirin at week 24-28 depending on placenta-associated biomarker risk stratification.

Evaluating Current Molecular Techniques and Evidence in Assessing Microbiome in Placenta-Related Health and Disorders in Pregnancy

The microbiome is of great interest due to its potential influence on the occurrence and treatment of some human illnesses. It may be regarded as disruptions to the delicate equilibrium that humans ordinarily maintain with their microorganisms or the microbiota in their environment. The focus of this review is on the methodologies and current understanding of the functional microbiome in pregnancy outcomes. We present how novel techniques bring new insights to the contemporary field of maternal-fetal medicine with a critical analysis. The maternal microbiome in late pregnancy has been extensively studied, although data on maternal microbial changes during the first trimester are rare. Research has demonstrated that, in healthy pregnancies, the origin of the placental microbiota is oral (gut) rather than vaginal. Implantation, placental development, and maternal adaptation to pregnancy are complex processes in which fetal and maternal cells interact. Microbiome dysbiosis or microbial metabolites are rising as potential moderators of antenatal illnesses related to the placenta, such as fetal growth restriction, preeclampsia, and others, including gestational diabetes and preterm deliveries. However, because of the presence of antimicrobial components, it is likely that the bacteria identified in placental tissue are (fragments of) bacteria that have been destroyed by the placenta's immune cells. Using genomic techniques (metagenomics, metatranscriptomics, and metaproteomics), it may be possible to predict some properties of a microorganism's genome and the biochemical (epigenetic DNA modification) and physical components of the placenta as its environment. Despite the results described in this review, this subject needs further research on some major and crucial aspects. The phases of an in utero translocation of the maternal gut microbiota to the fetus should be explored. With a predictive knowledge of the impacts of the disturbance on microbial communities that influence human health and the environment, genomics may hold the answer to the development of novel therapies for the health of pregnant women.

Pregnancy-specific responses to COVID-19 revealed by high-throughput proteomics of human plasma

BACKGROUND

Pregnant women are at greater risk of adverse outcomes, including mortality, as well as obstetrical complications resulting from COVID-19. However, pregnancy-specific changes that underlie such worsened outcomes remain unclear.

METHODS

Plasma samples were collected from pregnant women and non-pregnant individuals (male and female) with (n = 72 pregnant, 52 non-pregnant) and without (n = 29 pregnant, 41 non-pregnant) COVID-19. COVID-19 patients were grouped as asymptomatic, mild, moderate, severe, or critically ill according to NIH classifications. Proteomic profiling of 7,288 analytes corresponding to 6,596 unique protein targets was performed using the SOMAmer platform.

RESULTS

Herein, we profile the plasma proteome of pregnant and non-pregnant COVID-19 patients and controls and show alterations that display a dose-response relationship with disease severity; yet, such proteomic perturbations are dampened during pregnancy. In both pregnant and non-pregnant state, the proteome response induced by COVID-19 shows enrichment of mediators implicated in cytokine storm, endothelial dysfunction, and angiogenesis. Shared and pregnancy-specific proteomic changes are identified: pregnant women display a tailored response that may protect the conceptus from heightened inflammation, while non-pregnant individuals display a stronger response to repel infection. Furthermore, the plasma proteome can accurately identify COVID-19 patients, even when asymptomatic or with mild symptoms.

CONCLUSION

This study represents the most comprehensive characterization of the plasma proteome of pregnant and non-pregnant COVID-19 patients. Our findings emphasize the distinct immune modulation between the non-pregnant and pregnant states, providing insight into the pathogenesis of COVID-19 as well as a potential explanation for the more severe outcomes observed in pregnant women.

Women´s experiences of preeclampsia as a condition of uncertainty: a qualitative study

Background

Preeclampsia is a severe condition that annually affects about 3–8% of pregnancies worldwide. Preeclampsia is thereby one of the most common pregnancy complications for both mother and child. Despite that, there is limited research exploring the women´s perspective of experiencing preeclampsia.

Aim

The aim of this study was to describe women´s experiences of preeclampsia to improve the support and care given during and after pregnancy.

Methods

A qualitative descriptive interview study was undertaken. Nine women, diagnosed with preeclampsia, were recruited from a maternity unit in southern Sweden. The descriptive phenomenological method according to Amadeo Giorgi was used to analyse the data.

Results

The women´s experiences of PE were expressed as A condition of uncertainty, meaning that it was an unexpected and unknown situation. This main result consisted of 1) incomprehensible diagnosis message, 2) ambivalent feeling when the unexpected happens, 3) confusing contradictory messages, 4) appreciated support from the midwife, 5) need for continuous information. The nature of preeclampsia can sometimes deteriorate rapidly both for the mother and/or the child, often resulting in conversion from a planned vaginal spontaneous delivery to an emergency Caesarean section. The women narrated diffuse symptoms, and they experienced that they got contradictory information from different health care professionals regarding the severity of their disease. Detailed and continuous information is requested throughout the course of the disease, and the postpartum period.

Conclusion

This qualitative study reveal a need for improved clinical management. Health care professionals must be aware that women and their partners need detailed, consistent and repeated information about severity and prognosis to diminish the condition of uncertainty, confusion and fearful experience. The clinical implication would be a standardized preeclampsia education for pregnant women early on in the pregnancy, to raise awareness of preeclamptic symptoms. Furthermore, there is a need for harmonized guidelines and individualized support to the woman and her partner both at the antenatal care and the maternity ward and inpatient care at the hospital.

Placental Syndromes-A New Paradigm in Perinatology

Placental syndromes include pregnancy loss, fetal growth restriction, preeclampsia, preterm delivery, premature rupture of membranes, placental abruption and intrauterine fetal demise. This paper discusses the common etiopathogenesis of those syndromes and the role of angiogenic biomarkers in their development. Pregnancy implantation, placental development and maternal adaptation are complex processes in which fetal and maternal cells interact. The syncytiotrophoblast, trophoblast, uterine natural killer cells and regulatory T cells interfere and interact in all the above-mentioned processes. The proper angioneogenesis and vasculogenesis of the placenta, as well as maternal circulatory adaptation, are dependent on angiogenic factor expression. Insufficient maternal immunotolerance, dysregulation in uterine natural killer or regulatory T cell function, syncytiotrophoblast and trophoblast ischemia and hypoxia or impaired balance in angiogenic factors are all related to the occurrence of placental syndromes. Differences in the time of impairment onset and its intensity and correlation with other dysfunctions result in the development of a specific syndrome. The clinical manifestations in the form of a combination of specific symptoms determine the diagnosis. However, they are just symptoms of an underlying complex trophoblast disorder.

A Review of Nanotechnology for Treating Dysfunctional Placenta

The placenta plays a significant role during pregnancy. Placental dysfunction contributes to major obstetric complications, such as fetal growth restriction and preeclampsia. Currently, there is no effective treatment for placental dysfunction in the perinatal period, and prophylaxis is often delivered too late, at which point the disease manifestation cannot be prevented. However, with recent integration of nanoscience and medicine to perform elaborate experiments on the human placenta, it is expected that novel and efficient nanotherapies will be developed to resolve the challenge of managing placental dysfunction. The advent of nanomedicine has enabled the safe and targeted delivery of drugs using nanoparticles. These smart nanoparticles can load the necessary therapeutic substances that specifically target the placenta, such as drugs, targeting molecules, and ligands. Packaging multifunctional molecules into specific delivery systems with high targeting ability, diagnosis, and treatment has emerged as a novel theragnostic (both therapeutic and diagnostic) approach. In this review, the authors discuss recent advances in nanotechnology for placental dysfunction treatment. In particular, the authors highlight potential candidate nanoparticle-loaded molecules that target the placenta to improve utero-placental blood flow, and reduce reactive oxygen species and oxidative stress. The authors intend to provide basic insight and understanding of placental dysfunction, potential delivery targets, and recent research on placenta-targeted nanoparticle delivery systems for the potential treatment of placental dysfunction. The authors hope that this review will sensitize the reader for continued exploration of novel nanomedicines.

Failure of physiological transformation and spiral artery atherosis: their roles in preeclampsia

Physiological transformation with remodeling of the uteroplacental spiral arteries is key to a successful placentation and normal placental function. It is an intricate process that involves, but is not restricted to, complex interactions between maternal decidual immune cells and invasive trophoblasts in the uterine wall. In normal pregnancy, the smooth muscle cells of the arterial tunica media of uteroplacental spiral arteries are replaced by invading trophoblasts and fibrinoid, and the arterial diameter increases 5- to 10-fold. Poor remodeling of the uteroplacental spiral arteries is linked to early-onset preeclampsia and several other major obstetrical syndromes, including fetal growth restriction, placental abruption, and spontaneous preterm premature rupture of membranes. Extravillous endoglandular and endovenous trophoblast invasions have recently been put forth as potential contributors to these syndromes as well. The well-acknowledged disturbed extravillous invasion of maternal spiral arteries in preeclampsia is summarized, as are briefly novel concepts of disturbed extravillous endoglandular and endovenous trophoblast invasions. Acute atherosis is a foam cell lesion of the uteroplacental spiral arteries associated with poor remodeling. It shares some morphologic features with early stages of atherosclerosis, but several molecular differences between these lesions have also recently been revealed. Acute atherosis is most prevalent at the maternal-fetal interface, at the tip of the spiral arteries. The localization of acute atherosis downstream of poorly remodeled arteries suggests that alterations in blood flow may trigger inflammation and foam cell development. Acute atherosis within the decidua basalis is not, however, confined to unremodeled areas of spiral arteries or to hypertensive disorders of pregnancy and may even be present in some clinically uneventful pregnancies. Given that foam cells of atherosclerotic lesions are known to arise from smooth muscle cells or macrophages activated by multiple types of inflammatory stimulation, we have proposed that multiple forms of decidual vascular inflammation may cause acute atherosis, with or without poor remodeling and/or preeclampsia. Furthermore, we propose that acute atherosis may develop at different gestational ages, depending on the type and degree of the inflammatory insult. This review summarizes the current knowledge of spiral artery remodeling defects and acute atherosis in preeclampsia. Some controversies will be presented, including endovascular and interstitial trophoblast invasion depths, the concept of 2-stage trophoblast invasion, and whether the replacement of maternal spiral artery endothelium by fetal endovascular trophoblasts is permanent. We will discuss the role of acute atherosis in the pathophysiology of preeclampsia and short- and long-term health correlates. Finally, we suggest future opportunities for research on this intriguing uteroplacental interface between the mother and fetus.

Placenta in the Critically Ill Mother

The placenta is a temporary, multifunctional organ composed of both maternal and fetal components. It maintains homeostasis to ensure the growth of the fetus and well-being of the mother. Abnormalities in placental development have been known to be responsible for several disorders of pregnancy. Conditions coincident with pregnancy can upset the homeostasis and result in critical illness, which can greatly impact placental function and in turn affect the fetus. Decreased blood flow, acidemia, hypercarbia, and hypoxia seen in critically ill pregnant mothers can result in fetal death. Understanding the physiological changes and functioning of the maternal-fetal-placental unit will aid in better management of critically ill mothers.

How to cite this article

Taggarsi DA, Krishna B. Placenta in the Critically Ill Mother. Indian J Crit Care Med 2021;25(Suppl 3):S200-S205.

Longitudinal profile of sHLA-G during pregnancy and its association with small for gestational age births in North Indian pregnant females: A nested case-control study

PROBLEM

Small for gestational age (SGA) neonates are vulnerable to various long and short-term adverse health consequences. The expression of HLA-G in the placenta is crucial for establishment and maintenance of pregnancy. Its aberrant expression could lead to perturbed immunological interactions in the placenta which could be associated with SGA births. The objective of this study was to assess the difference in the trajectories of soluble HLA-G in maternal sera during pregnancy between women delivering SGA and appropriate for gestational age (AGA) neonates.

METHOD OF STUDY

Soluble HLA-G was estimated in the maternal sera collected at different time points in pregnancy of North-Indian pregnant females delivering SGA (N = 23) or AGA (N = 17) neonates using sandwich ELISA. Linear mixed models were built and compared to study the association between sHLA-G levels during pregnancy and SGA births.

RESULTS

No significant difference was observed in the sHLA-G trajectories during pregnancy in mothers delivering SGA as compared to those delivering AGA (P-value = .5677). A trend towards higher sHLA-G levels at the first trimester of pregnancy (< 14 weeks of gestation) was observed in mothers delivering SGA neonates (Median = 41.71, IQR = 21.31-71.38) as compared to those delivering AGA neonates (Median = 37.58, IQR = 19.05-73.57).

CONCLUSION

During pregnancy, sHLA-G trajectories do not differ significantly between mothers delivering SGA and those delivering AGA neonates. However, sHLA-G trends towards higher levels during early pregnancy in mothers delivering SGA neonates.

The Potent Antioxidant MitoQ Protects Against Preeclampsia During Late Gestation but Increases the Risk of Preeclampsia When Administered in Early Pregnancy

Aims: Although preeclampsia (PE) has been attributed to excessive oxidative stress (OS) in the placenta, mild antioxidants failed to prevent PE in clinical trials. As mitochondria are a major source of OS, this study assessed the potential of a potent mitochondria-targeting antioxidant MitoQ in the prevention of PE. Results: Placentas from women with PE and from reduced uterine perfusion pressure (RUPP) mice demonstrated significantly higher OS, along with increased mitochondrial damage and compromised glutathione peroxidase (GPx) activities. MitoQ administration during late gestation alleviated RUPP-induced PE; whereas early-pregnancy MitoQ treatment not only exacerbated blood pressure, fetal growth restriction, and proteinuria but also reduced the labyrinth/spongiotrophoblast ratio and blood sinuses in the labyrinth. Invasion (Matrigel transwell) and migration (wound healing assay) of trophoblasts were greatly improved by 1 μM hydrogen peroxide (H₂O₂), but this improvement was abolished by MitoQ or MitoTempo. Mild OS enhanced the expression of miR-29b-3p, which regulates five genes involved in viability and mobility, in HTR8-S/Vneo cells. Innovation and Conclusions: Although the potent mitochondrial-targeting antioxidant MitoQ protects against hypertension and kidney damage induced by RUPP in mice when administered in late gestation, it exacerbates the PE-like phenotype when given in early gestation by interfering with placenta formation because mild OS is required to stimulate trophoblast proliferation, invasion, and migration. Eliminating trophoblastic OS during early pregnancy may lead to compromised placentation and a risk of diseases of placental origin. Therefore, antioxidant therapy for pregnant women should be carefully considered.

The two-stage placental model of preeclampsia: An update

Early-onset preeclampsia has been linked to poor placentation and fetal growth restriction, whereas late-onset preeclampsia was suggested to result from maternal factors. We have proposed an alternative model, suggesting that both early- and late-onset preeclampsia result from placental syncytiotrophoblast stress. This stress represents a common endpoint of several Stage 1 processes, promoting the clinical stage 2 of preeclampsia (new-onset hypertension and proteinuria or other signs of end-organ dysfunction), but the causes and timing of placental malperfusion differ. We have suggested that late-onset preeclampsia, without evidence of poor spiral artery remodelling, may be secondary to intraplacental (intervillous) malperfusion due to mechanical restrictions. As the growing placenta reaches its size limit, malperfusion and hypoxia occurs. This latter pathway reflects what is observed in postmature or multiple pregnancies. Our revised two-stage model accommodates most risk factors for preeclampsia including primiparity, chronic pre-pregnancy disease (e.g. obesity, diabetic-, chronic hypertensive-, and some autoimmune diseases), and pregnancy risk factors (e.g. multiple or molar pregnancies, gestational diabetes or hypertension, and low circulating Placental Growth Factor). These factors may increase the risk of progressing to the second stage of preeclampsia (both early- and late-onset) by affecting one of or both pathways leading to Stage 1, as well as potentially accelerating the steps towards Stage 2, including priming the maternal cardiovascular susceptibility to inflammatory factors shed by the placenta. This paper reviews previous preeclampsia findings and concepts, which fit with the revised two-stage model, and argues that "maternal" preeclampsia does not exist, as all preeclampsia requires a placenta.

Extracellular vesicles generated by placental tissues ex vivo: A transport system for immune mediators and growth factors

PROBLEM

To study the mechanisms of placenta function and the role of extracellular vesicles (EVs) in pregnancy, it is necessary to develop an ex vivo system that retains placental cytoarchitecture and the primary metabolic aspects, in particular the release of EVs and soluble factors. Here, we developed such a system and investigated the pattern of secretion of cytokines, growth factors, and extracellular vesicles by placental villous and amnion tissues ex vivo.

METHODS OF STUDY

Placental villous and amnion explants were cultured for 2 weeks at the air/liquid interface and their morphology and the released cytokines and EVs were analyzed. Cytokines were analyzed with multiplexed bead assays, and individual EVs were analyzed with recently developed techniques that involved EV capture with magnetic nanoparticles coupled to anti-EV antibodies and flow cytometry.

RESULTS

Ex vivo tissues (i) remained viable and preserved their cytoarchitecture; (ii) maintained secretion of cytokines and growth factors; (iii) released EVs of syncytiotrophoblast and amnion epithelial cell origins that contain cytokines and growth factors.

CONCLUSION

A system of ex vivo placental villous and amnion tissues can be used as an adequate model to study placenta metabolic activity in normal and complicated pregnancies, in particular to characterize EVs by their surface markers and by encapsulated proteins. Establishment and benchmarking the placenta ex vivo system may provide new insight in the functional status of this organ in various placental disorders, particularly regarding the release of EVs and cytokines. Such EVs may have a prognostic value for pregnancy complications.

Vitamin D deficiency and pre-eclampsia in Colombia: PREVitD study

PURPOSE

Pre-eclampsia is a multisystem disorder characterized by new-onset hypertension and proteinuria during pregnancy. Pre-eclampsia remains a major cause of maternal death in low-income countries. Vitamin D has a very diverse biological role in cardiovascular diseases. This study will evaluate the association of vitamin D levels and relevance to pre-eclampsia.

METHODS

We conducted a case-control study of women recruited from the GenPE (Genetics and Pre-eclampsia) Colombian registry. This is a multicenter case-control study conducted in eight Colombian cities. 25-Hydroxyvitamin D (25(OH)D) concentration was measured using liquid-chromatography-tandem mass spectrometry from 1013 women with pre-eclampsia and 1015 mothers without pre-eclampsia (controls).

RESULTS

Fifty-two percent of women with pre-eclampsia were vitamin D deficient. The 25(OH)D concentrations were significantly lower in the pre-eclampsia (mean 29.99 ng/mL; 95% CI: 29.40-30.58 ng/mL) group compared to controls (mean 33.7 ng/mL; 95% CI: 33.20-34.30 ng/mL). In the unadjusted model, maternal vitamin D deficiency, defined by maternal 25(OH)D concentration <30 ng/mL, was associated with an increased probability of suffering from pre-eclampsia (OR 2.10; 95% CI, 1.75-2.51). After adjusting for covariates, a similarly increased probability of having pre-eclampsia was observed (OR 2.18; 95% CI, 1.80-2.64) among women with vitamin D deficiency, relative to controls.

CONCLUSION

Although the results suggest that low maternal concentrations of 25(OH)D increase pre-eclampsia risk, this evidence may not be indicative of a causal association. Future studies are needed to confirm a definite causal relationship between concentrations of vitamin D and the risk of pre-eclampsia, by means of powered clinical trials.

Immunological Tolerance, Pregnancy, and Preeclampsia: The Roles of Semen Microbes and the Father

Although it is widely considered, in many cases, to involve two separable stages (poor placentation followed by oxidative stress/inflammation), the precise originating causes of preeclampsia (PE) remain elusive. We have previously brought together some of the considerable evidence that a (dormant) microbial component is commonly a significant part of its etiology. However, apart from recognizing, consistent with this view, that the many inflammatory markers of PE are also increased in infection, we had little to say about immunity, whether innate or adaptive. In addition, we focused on the gut, oral and female urinary tract microbiomes as the main sources of the infection. We here marshall further evidence for an infectious component in PE, focusing on the immunological tolerance characteristic of pregnancy, and the well-established fact that increased exposure to the father's semen assists this immunological tolerance. As well as these benefits, however, semen is not sterile, microbial tolerance mechanisms may exist, and we also review the evidence that semen may be responsible for inoculating the developing conceptus (and maybe the placenta) with microbes, not all of which are benign. It is suggested that when they are not, this may be a significant cause of PE. A variety of epidemiological and other evidence is entirely consistent with this, not least correlations between semen infection, infertility and PE. Our view also leads to a series of other, testable predictions. Overall, we argue for a significant paternal role in the development of PE through microbial infection of the mother via insemination.

The role of vitamin D in pre-eclampsia: a systematic review

BACKGROUND

The etiology of pre-eclampsia (PE) is not yet fully understood, though current literature indicates an upregulation of inflammatory mediators produced by the placenta as a potential causal mechanism. Vitamin D is known to have anti-inflammatory properties and there is evidence of an inverse relationship between dietary calcium intake and the incidence of PE. Evidence of the role of vitamin D status and supplementation in the etiology and prevention of PE is reviewed in this article along with identification of research gaps to inform future studies.

METHODS

We conducted a structured literature search using MEDLINE electronic databases to identify published studies until February 2015. These sources were retrieved, collected, indexed, and assessed for availability of pregnancy-related data on PE and vitamin D.

RESULTS

Several case-control studies and cross-sectional studies have shown an association between vitamin D status and PE, although evidence has been inconsistent. Clinical trials to date have been unable to show an independent effect of vitamin D supplementation in preventing PE.

CONCLUSIONS

The included clinical trials do not show an independent effect of vitamin D supplementation in preventing PE; however, issues with dose, timing, and duration of supplementation have not been completely addressed.

The emerging role of endothelin-1 in the pathogenesis of pre-eclampsia

Pre-eclampsia (PE) is the most frequently encountered medical complication during pregnancy. It is characterized by a rise in systemic vascular resistance with a relatively low cardiac output and hypovolemia, combined with severe proteinuria. Despite the hypovolemia, renin-angiotensin system (RAS) activity is suppressed and aldosterone levels are decreased to the same degree as renin. This suggests that the RAS is not the cause of the hypertension in PE, but rather that its suppression is the consequence of the rise in blood pressure. Abnormal placentation early in pregnancy is widely assumed to be an important initial event in the onset of PE. Eventually, this results in the release of anti-angiogenic factors [in particular, soluble Fms-like tyrosine kinase-1 (sFlt-1)] and cytokines, leading to generalized vascular dysfunction. Elevated sFlt-1 levels bind and inactivate vascular endothelial growth factor (VEGF). Of interest, VEGF inhibition with drugs like sunitinib, applied in cancer patients, results in a PE-like syndrome, characterized by hypertension, proteinuria and renal toxicity. Both in cancer patients treated with sunitinib and in pregnant women with PE, significant rises in endothelin-1 occur. Multiple regression analysis revealed that endothelin-1 is an independent determinant of the hypertension and proteinuria in PE, and additionally a renin suppressor. Moreover, studies in animal models representative of PE, have shown that endothelin receptor blockers prevent the development of this disease. Similarly, endothelin receptor blockers are protective during sunitinib treatment. Taken together, activation of the endothelin system emerges as an important pathway causing the clinical manifestations of PE. This paper critically addresses this concept, taking into consideration both clinical and preclinical data, and simultaneously discusses the therapeutic consequences of this observation.

Unravelling the theories of pre-eclampsia: are the protective pathways the new paradigm?

Pre-eclampsia is a vascular disorder of pregnancy where anti-angiogenic factors, systemic inflammation and oxidative stress predominate, but none can claim to cause pre-eclampsia. This review provides an alternative to the ‘two-stage model’ of pre-eclampsia in which abnormal spiral arteries modification leads to placental hypoxia, oxidative stress and aberrant maternal systemic inflammation. Very high maternal soluble fms-like tyrosine kinase-1 (sFlt-1 also known as sVEGFR) and very low placenta growth factor (PlGF) are unique to pre-eclampsia; however, abnormal spiral arteries and excessive inflammation are also prevalent in other placental disorders. Metaphorically speaking, pregnancy can be viewed as a car with an accelerator and brakes, where inflammation, oxidative stress and an imbalance in the angiogenic milieu act as the ‘accelerator’. The ‘braking system’ includes the protective pathways of haem oxygenase 1 (also referred as Hmox1 or HO-1) and cystathionine-γ-lyase (also known as CSE or Cth), which generate carbon monoxide (CO) and hydrogen sulphide (H₂S) respectively. The failure in these pathways (brakes) results in the pregnancy going out of control and the system crashing. Put simply, pre-eclampsia is an accelerator–brake defect disorder. CO and H₂S hold great promise because of their unique ability to suppress the anti-angiogenic factors sFlt-1 and soluble endoglin as well as to promote PlGF and endothelial NOS activity. The key to finding a cure lies in the identification of cheap, safe and effective drugs that induce the braking system to keep the pregnancy vehicle on track past the finishing line.

Galectin signature in normal pregnancy and preeclampsia

Members of the galectin family are expressed within the female reproductive tract and have been shown to be involved in multiple biological functions that support the progression of pregnancy. Specific expression patterns of different members of this family have been identified at the maternal decidua and on the placental side. In some cases, mechanisms by which galectins exert their functions have been delineated in adverse pregnancy outcomes. This review summarizes studies on galectins that have been documented to be important for pregnancy maintenance, either supporting the maternal adaptation to pregnancy or the placentation process. In addition, we focus our discussion on the role of galectins in preeclampsia, a specific life-threatening pregnancy disorder.

Inflammation and preeclampsia

No individual can claim credit for all the advances made during his lifetime. However, certain individuals have a far greater influence than others. Prof. Christopher Redman has had a huge role to play in increasing the understanding of the aetiology, pathology, progression and management of preeclampsia. The work he did personally, led in others and stimulated in colleagues, both friend and foe, has helped to progress preeclampsia from a disease that came from nowhere to one that is more understood and safely managed. In this paper, it is the work in immunology that will be concentrated on in a chronological way but this will be linked to other relevant research and clinical practice. The understanding that preeclampsia is a two-stage disease starting in the placenta and progressing systemically has led to greater understanding as well as more questions. The universal role of immunology first as an acceptor within the placental bed then as a disease driver in the systemic circulation emphasises the good and the bad in physiological systems. Prof. Redman has been present in all these areas of discovery and enlightenment as will be described.

Sera from preeclampsia patients elicit symptoms of human disease in mice and provide a basis for an in vitro predictive assay

Early diagnosis and treatment of preeclampsia would significantly reduce maternal and fetal morbidity and mortality. However, its etiology and prediction have remained elusive. Based on the hypothesis that sera from patients with preeclampsia could function as a "blueprint" of causative factors, we describe a serum-based pregnancy-specific mouse model that closely mirrors the human condition as well as an in vitro predictive assay. We show that a single administration of human preeclampsia serum in pregnant IL-10-/- mice induced the full spectrum of preeclampsia-like symptoms, caused hypoxic injury in uteroplacental tissues, and elevated soluble fms-like tyrosine kinase 1 and soluble endoglin, markers thought to be related to the disease. The same serum sample(s) induced a partial preeclampsia phenotype in wild-type mice. Importantly, preeclampsia serum disrupted cross talk between trophoblasts and endothelial cells in an in vitro model of endovascular activity. Disruption of endovascular activity could be documented in serum samples as early as 12 to 14 weeks of gestation from patients who subsequently developed preeclampsia. These results indicate that preeclampsia patient sera can be used to understand the pregnancy-specific disease pathology in mice and can predict the disorder.

Trophoblast function in normal and preeclamptic pregnancy

Preeclampsia (PE) is a common disease of pregnancy that affects women particularly in their first pregnancies. Current estimates suggest that between 7 and 10% of pregnancies may be complicated by PE. Despite considerable research and medical efforts, the incidence of the disease has not changed substantially in the last century. In severe cases the disease may be life-threatening and is associated with high neonatal mortality and morbidity. Furthermore, therapy is often ineffective and at best treats the disease symptoms rather than the aetiology. One reason for the lack of progress may be that while the disease is generally agreed by most to be due to abnormal implantation and development of the placenta (events which happen in the first trimester) most research efforts have focused on managing and understanding the maternal disease. Since the disease typically appears in the last trimester, many weeks after the likely start of the pathology, it has been difficult to understand the progression of events. However, this picture has improved recently. The purpose here is to review how placental development is affected in PE and describe new insights into the causes. It is hoped that an understanding of the pathogenesis of the placental defects in PE will lead to new efforts towards early diagnosis, before the onset of clinical symptoms, as well as new treatments for these lesions.

TNF-alpha from monocyte of patients with pre-eclampsia-induced apoptosis in human trophoblast cell line

OBJECTIVE

In pre-eclampsia, fetal growth restriction is frequently observed, and the possible involvement of inhibitory substances on trophoblast cell proliferation and differentiation has been suggested. The objective of this study was to investigate the effects humoral factors, such as cytokines, produced in immune cells on proliferation of an immortalized trophoblastic cell line (TCL) that we established.

METHODS

Serum and lymphocyte layers were isolated from the blood of normal pregnant and preeclamptic women. The lymphocyte layer was further fractionated into different immune cell populations by the Stem Sep method. Immortalized trophoblastic cells were cultured with the sera diluted. The cytokine concentrations in the supernatants of lymphocyte cultures were compared between normal pregnancy and pre-eclampsia. The number, DNA content and induced apoptosis were examined on the immortalized trophoblastic cells at the end of culture.

RESULTS

The sera from preeclamptic women significantly inhibited the immortalized trophoblastic cell proliferation in comparison with those from normal pregnancy. Among the lymphocyte fractions, monocytes significantly inhibited the immortalized trophoblastic cell proliferation. The monocytes from preeclamptic women were found to produce higher levels of tumor necrosis factor-alpha (TNF-alpha) in the culture supernatant than those from normal pregnant women. The coculture with the monocytes from preeclamptic women increased the frequency of TUNEL-positive TCL cells. TNF-alpha inhibited immortalized trophoblastic cell proliferation in a dose-dependent manner and induced apoptosis.

CONCLUSION

The present results suggest that monocytes are activated and that cytokines, such as TNF-alpha, which is produced by monocytes, induce apoptosis and inhibit proliferation of trophoblast cells in pre-eclampsia.

Activated T Lymphocytes in Pre-Eclampsia

PROBLEM

The aim of our study was to investigate the activation markets of T CD3(+), T helper CD4(+) and T cytotoxic CD8(+) cells, as well as, the populations of T naïve CD4(+) CD45RA(+), T memory CD4(+) CD45RO(+) and T regulatory lymphocytes in PE and healthy pregnant women.

METHOD OF STUDY

Twenty-five patients with PE and thirty healthy third trimester pregnant women were included in the study. Peripheral blood mononuclear cells were isolated from peripheral blood, stained with monoclonal antibodies and estimated using the flow cytometric method.

RESULTS

The percentages of CD4(+)CD25(+), CD4(+)CD25(dim), CD3(+)HLA-DR(+), CD4(+)HLA-DR(+) and CD8(+)HLA-DR(+) cells did not differ between study groups. The population of T regulatory CD4(+)CD25(bright) lymphocytes was significantly lower in the group of patients with PE when compared with the controls (P < 0.01). The percentages of CD3(+)CD25(+) (P < 0.05), CD8(+)CD25(+) (P < 0.05), CD4(+)45RO(+) (P < 0.01) lymphocytes were significantly higher, while CD4(+)CD45RA(+) (P < 0.01) cells--significantly lower in peripheral blood of patients with PE when compared with the control group.

CONCLUSION

The increased levels of T CD4(+)45RO(+) and T CD8(+) CD25(+) cells can suggest the activation of CD4(+) and CD8(+) T lymphocytes in pre-eclampsia. It seems possible that the activation of T lymphocytes is associated with the deficiency of T regulatory cells in PE.

Recurrent preterm birth

Recurrent preterm birth is frequently defined as two or more deliveries before 37 completed weeks of gestation. The recurrence rate varies as a function of the antecedent for preterm birth: spontaneous versus indicated. Spontaneous preterm birth is the result of either preterm labor with intact membranes or preterm prelabor rupture of the membranes. This article reviews the body of literature describing the risk of recurrence of spontaneous and indicated preterm birth. Also discussed are the factors which modify the risk for recurrent spontaneous preterm birth (a short sonographic cervical length and a positive cervicovaginal fetal fibronectin test). Patients with a history of an indicated preterm birth are at risk not only for recurrence of this subtype, but also for spontaneous preterm birth. Individuals of black origin have a higher rate of recurrent preterm birth.

Maternal and fetal plasma adenosine deaminase, xanthine oxidase and malondialdehyde levels in pre-eclampsia

The aim of this study was to evaluate maternal-fetal plasma adenosine deaminase, xanthine oxidase (ADA, XO) activity and malondialdehyde (MDA) levels and the relationship between them in pre-eclampsia. Maternal and umbilical cord whole blood samples were taken from 29 pre-eclamptic and 33 normal pregnants. The plasma ADA, XO activities as well as MDA levels were assayed by spectrophotometric methods. MDA levels and ADA, XO activities were found to be higher in maternal and fetal plasma in pre-eclamptics than in normal pregnancy. The differences were statistically significant between groups (p < 0.05). Increased maternal-fetal plasma XO and ADA activities, as a marker of immunological disorder, may be related to the pathogenesis of pre-eclampsia. In addition, increased MDA levels may be a reflection of increased oxidative stress in pre-eclamptics and their fetuses.

Placental barrier breakage in preeclampsia: ultrastructural evidence

OBJECTIVE

It is known that the placenta acts as an immunological barrier between the mother and fetal "graft" allowing two antigenically different organisms to tolerate one another. Preeclampsia may be considered as a fetal rejection consequent to severe damage at placental endothelial and syncytiotrophoblast level. In order to verify this placental barrier damage we undertook the present study by electron microscopy.

STUDY DESIGN

14 placentae from preeclaptic women, and the same number of placentae from healthy controls were examined.

RESULTS

The results showed that endothelial cells from preeclamptic placentae express various and severe alterations, consisting of swollen and bulbous cytoplasm, degenerated inter-endothelial junctions with consequent crossing of fetal blood cells outside the vessels.

CONCLUSIONS

These lesions could be the ultrastructural evidence of the placental barrier breakage leading to rejective reaction we presumed to be basis of preeclampsia.

Myeloid and lymphoid dendritic cells in normal pregnancy and pre-eclampsia

The aim of our study was to estimate the populations of peripheral blood myeloid and lymphoid dendritic cells (CD1c+, BDCA-2+) and the CD1c+ : BDCA-2+ ratio in normal pregnant women and in patients with pre-eclampsia. Fifteen women in the first, second and third trimesters of normal pregnancy, and 25 patients with pre-eclampsia were included in the study. The dendritic cells were isolated from peripheral blood, stained with monoclonal antibodies against blood dendritic cell antigens (anti-CD1c, anti-BDCA-2) and estimated using the flow cytometric method. CD1c+ and BDCA-2+ dendritic cells were present in women during all trimesters of physiological pregnancy and in pre-eclamptic patients. It was observed that the numbers of dendritic cells were significantly lower in the second trimester when compared with the first and third trimesters of normal pregnancy. Furthermore, in the second trimester, CD1c+ : BDCA-2+ ratio was higher than in the other trimesters of physiological pregnancy. All populations of dendritic cells and CD1c+ : BDCA-2+ ratio did not differ in the first and third trimesters of normal pregnancy. The percentage of BDCA-2+ dendritic cells was significantly lower in pre-eclampsia in comparison with healthy women in the third trimester of physiological pregnancy, while CD1c+ : BDCA-2+ ratio was significantly higher in pre-eclamptic patients when compared with control groups. We concluded that dendritic cells may be involved in the immune regulation during physiological pregnancy. CD1c+ and BDCA-2+ cells can influence the Th2 phenomenon which is observed during physiological pregnancy. Furthermore, it seems possible that lower BDCA-2+ cells percentage and higher CD1c+ : BDCA-2+ ratio can be associated with increased Th1-type immunity in patients with pre-eclampsia.

The expressions of intracellular cytokines in the lymphocytes of preeclamptic patients

PURPOSE

The objective of the study was to investigate the intracellular expressions of T helper 1 (Th1) and Th2 cytokines in peripheral blood T lymhocytes and natural killer (NK) cells of patients with preeclampsia and women with uncomplicated pregnancy.

METHOD OF STUDY

Blood samples were taken from 20 patients with preeclampsia and 16 healthy pregnant women. Mononuclear cells were isolated from peripheral blood and stimulated for 5 hr at 37 degrees C and 5% CO2. Next, the cells were stained with antibodies against surface markers of T-cell subsets and NK cells. After fixation and permeabilization processes, the cells were stained with antibodies against intracellular cytokines--interleukin-2 (Il-2) and interferon-gamma (IFN-gamma) as well as Il-10 and Il-4. The intracellular expressions of Th1 and Th2 cytokines were determined using the flow cytometric method. Statistical analysis was performed using Mann-Whitney U-test.

RESULTS

We found that in patients with preeclampsia the expressions of Il-2 were significantly higher when compared with women with uncomplicated pregnancy. Furthermore, in the group of patients with preeclampsia the expressions of Il-2 were higher in T CD 8+ lymphocytes than in T CD4+ cells. The expressions of IFN-gamma did not differ in CD4+ cells and CD8+ cells in both studied groups but they were higher in NK cells in the study group. The expressions of Il-10 were lower in lymphocytes of preeclamptic patients when compared with controls. The expressions of Il-4 did not differ in both studied groups.

CONCLUSIONS

These results suggest that in patients with preeclampsia there is Th1/Th2 imbalance, with predominant Th1 immunity.

Relationship between plasma malondialdehyde levels and adenosine deaminase activities in preeclampsia

BACKGROUND

Preeclampsia is characterized by endothelial cell dysfunction, and lipid peroxidation and alterations of immune responses may be involved in the pathogenesis of this disease. The aim of the present study was to examine changes in plasma malondialdehyde (MDA) level, an indicator of lipid peroxidation, and adenosine deaminase (ADA) activity, as a marker of T-cell activation in preeclampsia, and evaluated the possible relationship between those parameters in the pathogenesis of preeclampsia.

METHODS

Plasma levels of MDA, an end product of lipid peroxidation induced by reactive oxygen species, and ADA activities were measured in 26 women with preeclampsia and 26 normal pregnancies.

RESULTS

In preeclampsia, plasma MDA level and ADA activity averaged 0.43 +/- 0.03 micromol/l and 15.8 +/- 0.8 U/l, respectively, which were significantly higher than those of normal pregnancy (0.31 +/- 0.02 micromol/l and 9.5 +/ -0.6 U/l, respectively) (P<0.05). In addition, plasma MDA level was positively correlated to ADA activity in preeclampsia (r=0.52, P<0.05).

CONCLUSIONS

These results suggest that enhanced lipid peroxidation and T-cell activation, and the presence of possible interrelationship and cross talk between those parameters may be related at least partly to the pathogenesis of preeclampsia.

Activated protein C in normal human pregnancy and pregnancies complicated by severe preeclampsia: a therapeutic opportunity?

OBJECTIVES

Given the efficacy and safety of recombinant human activated protein C (rhAPC) in the systemic inflammatory response syndrome, this study was designed to review the evidence for a role for APC in the pathogenesis of preeclampsia. Preeclampsia is a proinflammatory and procoagulant state, and it is a pregnancy-specific condition that mimics the systemic inflammatory response syndrome. rhAPC reduces mortality in patients with systemic inflammatory response syndrome and could potentially have a role as disease-modifying therapy in preeclampsia. To determine which patients would be offered rhAPC, the literature pertaining to fetal/neonatal outcomes for preeclampsia remote from term, transplacental transport of protein C, and pregnancy experience with the compound were reviewed.

DATA SOURCES

MEDLINE, review papers, hand searches of relevant nonindexed journals, and the bibliographies of relevant textbooks and articles reviewed.

STUDY SELECTION

Randomized controlled trials were considered to provide the best quality of clinical data. Case-control series were considered over uncontrolled data. Some data were not available in the published literature (e.g., neonatal outcomes at various gestational ages and birthweights after a hypertensive pregnancy; and transplacental transfer of protein C), and these data were determined by us.

DATA EXTRACTION

Data were extracted by systematic review onto data collection sheets. Because of the quality of the data, this review is primarily qualitative.

DATA SYNTHESIS

APC levels fall during normal gestation, returning to normal values by 6 wks postpartum. Limited data suggest that early onset preeclampsia is a state of further, and inappropriate, reduction in APC. Preeclampsia resembles systemic inflammatory response syndrome in this regard. After hypertensive pregnancies, neonates have a 50% chance of intact survival if delivered after 27 + 0 wks of gestation with a birthweight of >600 g. It would seem ethical to offer women with preeclampsia with <50% chance of intact perinatal survival novel and potentially disease-modifying therapy such as rhAPC, especially as there is no transplacental transfer of protein C. Limited evidence would support the use of rhAPC in women with severe postpartum preeclampsia.

CONCLUSIONS

Sufficient data exist to support the use of rhAPC in phase II clinical studies for women with either early onset preeclampsia or severe or deteriorating postpartum disease.

The expression and concentrations of Fas/APO-1 (CD95) antigen in patients with severe pre-eclampsia

PROBLEM

Apoptosis has been proposed as a mechanism for maintaining homeostasis in the immune system. Activated lymphocytes are removed by a Fas/FasL-mediated programmed cell death process called activation induced cell death (AICD). The aim of the study was to investigate surface Fas antigen (APO-1, CD95) expression on T lymphocytes and NK cells and also soluble Fas antigen concentrations in pre-eclamptic patients and healthy pregnant women.

MATERIALS AND METHODS

Sixteen pre-eclamptic patients and 18 healthy pregnant women were studied. Peripheral blood lymphocytes were isolated, labeled by direct staining with anti-CD95 monoclonal antibodies and analyzed using the flow cytometric method. Furthermore, the concentrations of soluble CD95 molecule in serum of patients with severe pre-eclampsia and women with uncomplicated pregnancy were measured using ELISA method.

RESULTS

We found that Fas antigen expression and fluorescence intensity on T CD8+ lymphocytes were higher in patients with severe pre-eclampsia in comparison with healthy pregnant women (P<0.05). Furthermore, the concentrations of soluble CD95 molecule were higher in the group of pre-eclamptic patients when compared to controls (P<0.001).

CONCLUSIONS

These findings suggest that T CD8+ lymphocytes in patients with severe pre-eclampsia can be activated. Moreover, higher concentrations of soluble CD95 antigen can suggest altered possibilities to undergo Fas/FasL-mediated activation induced cell death process of lymphocytes in severe pre-eclampsia.

Nasal continuous positive airway pressure reduces sleep-induced blood pressure increments in preeclampsia

Preeclampsia is the predominant cause of admissions to neonatal intensive care. The diurnal blood pressure pattern is flattened or reversed in preeclampsia. We hypothesized that snoring and partial upper airway obstruction contribute to nocturnal rises in blood pressure. We tested this hypothesis by controlling sleep- induced upper airway flow limitation and snoring with nasal positive pressure. Eleven women with preeclampsia underwent two consecutive polygraphic sleep studies with simultaneous beat-to-beat blood pressure monitoring. Average blood pressure for the night overall and in each sleep stage was calculated. Sleep architecture was similar on the two study nights. Sleep-induced partial upper airway flow limitation occurred in all patients in the initial study. Autosetting nasal continuous positive airway pressure (CPAP) applied at a mean maximal pressure of 6 +/- 1 cm H(2)O eliminated flow limitation throughout sleep on the treatment night. Blood pressure was markedly reduced on the treatment night [(128 +/- 3)/(73 +/- 3)] when compared with the initial nontreatment study night [(146 +/- 6)/(92 +/- 4)], p = (0.007)/(0.002). We conclude that partial upper airway obstruction during sleep in women with preeclampsia is associated with increments in blood pressure, which can be eliminated with the use of nasal CPAP.

Serum levels of ELAM-1, but not CD44, predict the clinical outcome of patients with preeclampsia

OBJECTIVE

Preeclampsia is a severe complication in pregnancy, causing considerable maternal and fetal morbidity and mortality. Experimental evidence indicates that adhesion molecules are key factors of endothelial activation in preeclampsia. The aim of our study was to evaluate if serum levels of adhesion molecules CD44 and ELAM-1 provide clinically useful information as prognostic markers for preeclampsia.

METHODS

A matched-pair study including 43 women with preeclampsia and 43 women with uncomplicated pregnancies was performed. Enzyme-linked immunosorbent assay (ELISA) was used to determine serum levels of CD44 and ELAM-1. Results were correlated with clinical data.

RESULTS

Median serum levels of ELAM-1 in controls and in women with preeclampsia were 8.9 ng/mL (minimum 0, maximum 20.0) and 12.0 ng/mL (minimum 4.0, maximum 27.0), respectively (Kruskal-Wallis test, p = 0.01). In a univariate logistic regression model, ELAM-1 did reveal a significant influence on the odds of presenting with preeclampsia as well as on the odds of premature termination of the pregnancy due to preeclampsia (univariate logistic regression, p = 0.03 and p = 0.01, respectively). The risk of premature termination of the pregnancy was 0.5%, 15.3%, and 80.5% at ELAM-1 serum levels of 0 ng/mL, 10 ng/mL, and 20 ng/mL, respectively. No significant correlation between CD44 serum levels and clinicopathological parameters due to preeclampsia was observed.

CONCLUSIONS

If these results are confirmed in a larger series, ELAM-1 could be used as a prognostic factor in preeclamptic women, allowing early identification and appropriate management of high-risk patients with preeclampsia. It is unlikely that measurement of ELAM-1 will be of value as a screening test.

T helper 1- and T helper 2-type cytokine imbalance in pregnant women with pre-eclampsia

OBJECTIVES

The purpose of our study was to investigate T helper 1/T helper 2 balance in pregnant women with pre-eclampsia.

STUDY DESIGN

18 patients with pre-eclampsia and 20 healthy pregnant women were included in the study. Peripheral blood mononuclear cells (PBMC) were stimulated with phytohaemagglutinin (PHA) for 48 h. Cytokine: interleukin-2 (11-2), interferon-gamma (IFN-gamma) and interleukin-10 (I1-10) concentrations in culture supernatants were determined using the ELISA method. Statistical analysis was performed using a standard non-parametric Mann-Whitney U-test.

RESULTS

We found that in pre-eclamptic patients PHA-stimulated 11-2 and IFN-y production was significantly higher (P<0.001) and I1-10 production significantly lower (P<0.005) in comparison with the control group.

CONCLUSION

These results could suggest that there is Th1/Th2 imbalance in pre-eclamptic patients with predominant Th1-type immunity.

Evaluation of nonspecific immunity and plasma levels of interferon-gamma, interleukin-6 and tumor necrosis factor-alpha in preeclampsia

In this study we evaluated the maternal cell-mediated immune aspects of preeclampsia in terms of phagocytosis and killing of monocytes and polymorphonuclear cells. To evaluate the contribution of cytokines (Cks) in the pathophysiology of preeclampsia, we investigated the plasma levels of interferon-gamma (IFN-gamma), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha), respectively, by an enzyme-linked immunosorbent assay. Data showed that phagocytic and killing activities of monocytes were depressed in preeclamptic and normal pregnancies. At the same time, IFN-gamma plasma levels were undectable in both groups. Conversely, we detected significant levels of TNF-alpha in plasma from preeclamptic and normal pregnancies. Moreover, since in three preeclamptic patients the onset of severe preeclampsia was associated with a sharp increased of TNF-alpha plasma levels, we suggest that an increased production of this CK may be implicated in the pathophysiology of preeclampsia.

Increased incidence of preeclampsia in women conceiving by intrauterine insemination with donor versus partner sperm for treatment of primary infertility

OBJECTIVE

Reports suggest that there is an increased incidence of preeclampsia after a previously normal pregnancy if there is a change in paternity. We hypothesize that there is a higher incidence of preeclampsia (proteinuric hypertension) in women conceiving by intrauterine insemination with donor sperm versus intrauterine insemination with partner sperm.

STUDY DESIGN

This was a retrospective cohort study. In women with primary infertility all pregnancies achieved by either partner or donor intrauterine insemination carried to birth of a fetus (> 20 weeks) were identified. The medical records were examined for the maternal and pregnancy outcome data. The relative risk and 95% confidence interval were calculated for the risk of preeclampsia. The baseline data were compared with t tests, chi 2 analysis and Fisher's exact test where appropriate.

RESULTS

Forty-four patients in the partner intrauterine insemination group and 37 in the donor insemination group were identified as having primary infertility. Three cases of mild preeclampsia were found in the partner insemination program and nine cases of preeclampsia (five severe, four mild) in the donor insemination program (relative risk 1.85, 95% confidence interval 1.20 to 2.85).

CONCLUSIONS

There is a higher incidence of preeclampsia in women conceiving by intrauterine insemination with washed donor sperm compared with intrauterine insemination with washed partner sperm. This supports, indirectly, an immunologic basis for preeclampsia. The antigenic factor would appear to be located on the sperm as opposed to the seminal fluid itself.

Can flow cytometric detection of platelet activation early in pregnancy predict the occurrence of preeclampsia? A prospective study

OBJECTIVES

An increased platelet activation status is present in patients with preeclampsia. Our purpose was (1) to establish by means of flow cytometry whether platelets circulate in an activated state during the first and second trimesters of pregnancy and (2) to establish whether early platelet activation predicts the onset of preeclampsia.

STUDY DESIGN

Consecutively, 244 pregnant women were included in a prospective study design. Platelets in whole blood samples from the pregnant women in the first trimester, the second trimester, and after delivery were labeled with the following antibodies associated with platelet activation: anti-CD62P (P-selectin, alpha-granule secretion), anti-CD63 (GP53, lysosomal secretion), anti-CD31 (GPIIa', platelet endothelial cell adhesion molecule-1). The surface antigen exposure was determined by double-label flow cytometry with anti-CD42b (GPIb, a platelet-specific monoclonal glycoprotein) to select platelets and platelet-derived materials. Preeclampsia was defined as a diastolic blood pressure > or = 90 mm Hg and proteinuria > or = 0.3 gm in a 24-hour urine sample (International Society for Study of Hypertension in Pregnancy criteria).

RESULTS

Seventeen of 244 patients had preeclampsia (6.9%). Only first-trimester CD63 expression had an area under the curve > 0.5 by receiver-operator characteristic curve analysis and was selected as a possible predictor of preeclampsia. We found a sensitivity of 47% and a specificity of 76% with use of a percentage of activated platelets above 2% as a positive test. Likelihood ratios were 1.94 for positive likelihood and 0.69 for negative likelihood. Univariate logistic regression analysis results were odds ratio 2.8 (95% confidence interval 1.0 to 7.6). Multivariate logistic regression analysis results were odds ratio 2.9 (95% confidence interval 0.92 to 8.9). However, the odds ratio of first antenatal diastolic blood pressure was two to four times higher than the odds ratio of first-trimester CD63 expression. The combination of first-trimester CD63 and first antenatal diastolic blood pressure increases the positive likelihood ratio from 1.94 to 9.4, with a sensitivity of 41%, a specificity of 96%, and a negative likelihood ratio of 0.62.

CONCLUSIONS

Increased first-trimester CD63 expression is an independent risk factor for development of preeclampsia. CD63 expression might be useful to identify a subgroup of patients with a high risk for development of preeclampsia, especially in combination with first-trimester antenatal diastolic blood pressure. This method of patient selection may enable more efficient intervention studies in patients at risk than do the selection methods used so far.

Placental cytokines and the pathogenesis of preeclampsia

The authors explore the hypothesis that tumor necrosis factor-alpha (TNF-alpha) and possibly other inflammatory cytokines are overproduced by the placenta in response to local ischemia/hypoxia contributing to increased plasma levels, and subsequent endothelial activation and dysfunction in the pregnancy disorder, preeclampsia. It is widely held that inadequate trophoblast invasion and physiologic remodeling of spiral arteries initiate placental ischemia/hypoxia in preeclampsia. Furthermore, focal areas of placental hypoxia have been implicated in the production of "toxic" factor(s) by the placenta, which circulate and cause maternal disease. Placental trophoblast cells and fetoplacental macrophages normally produce TNF-alpha and interleukin-1 (IL-1), which are capable of producing endothelial cell activation and dysfunction. Hypoxia has recently been reported to increase TNF-alpha and IL-1 production by term villous explants from the human placenta. Placental cells also express erythropoietin (EPO), which is the prototype molecule for transcriptional regulation by hypoxia in mammals. Interestingly, TNF-alpha and IL-1 have DNA sequence homologous or nearly homologous to the hypoxia-responsive enhancer element of the EPO gene, thus providing a potential, but as of yet, untested molecular link between placental hypoxia and stimulation of cytokine production. Inflammatory cytokines overproduced by the placenta in response to hypoxia may then lead to increased plasma levels and endothelial activation and dysfunction in preeclampsia. The purpose of this short review is to critically evaluate the hypothesis that placental cytokines contribute to the pathogenesis of preeclampsia. Of note, the etiology of the disease presumably related to deficient trophoblast invasion is beyond the scope of this work.

Reduction in erythrocyte complement receptor 1 (CR1, CD35) and decay accelerating factor (DAF, CD55) during normal pregnancy

RBC-membrane CR1 has been assayed in pregnancy and at 48 h postpartum. It has been shown that RBC CR1 is reduced as pregnancy progress, reaching a nadir in the third trimester and that it returns to levels approaching normal within 48 h postpartum. Further, there is a reduced expression of RBC decay accelerating factor (DAF) during pregnancy but no change in expression of RBC CD59. We suggest that the reduction in RBC CR1 and DAF may reflect increased levels of circulating immune complexes and consequent increased complement activation in pregnancy.

Elevations of serum interleukin-12 concentrations in women with severe pre-eclampsia and HELLP syndrome

The objective is to test the hypothesis that serum IL-12 concentrations would be elevated in women with severe pre-eclampsia and HELLP syndrome. The Methods used were as follows: Serum was obtained from women admitted to our Labor and Delivery unit diagnosed with severe pre-eclampsia or HELLP syndrome and normal control patients. IL-12 concentrations in these samples were determined by the use of two different and specific enzyme-linked immunosorbent assays for the p40 subunit and the intact p75 dimer. It was found that serum IL-12 (p40 subunit) concentrations were elevated in women with both severe pre-eclampsia (p = 0.011) or HELLP syndrome (= 0.004). Similar findings were noted for these patients when matched with control patients for maternal age, gestational age, and parity. Eleven women had elevations of serum IL-12 p75 dimer, and 10 of these 11 patients had severe pre-eclampsia or HELLP syndrome. In conclusion, we found that women with severe pre-eclampsia and HELLP syndrome commonly have detectable concentrations of the IL-12 p40 monomer and were more likely than normal control women to have detectable serum IL-12 p75 dimer. While the exact role of IL-12 in hypertensive disease during pregnancy is unclear, our data support the hypothesis that the regulation of IL-12 production and metabolism is abnormal in women with pre-eclampsia and HELLP syndrome, perhaps contributing to the immunologic alterations characteristic of these disorders.

High levels of Lp(a) lipoprotein in a family with cases of severe pre-eclampsia

We report a family with two cases of severe pre-eclampsia/eclampsia in which very high levels of Lp(a) lipoprotein were found. The serum level of Lp(a) lipoprotein is genetically determined and the Lp(a) apolipoprotein has a close homology to plasminogen. Very high levels of Lp(a) lipoprotein might interfere with the fibrinolytic/thrombolytic process in man. A previous report suggested that a high maternal serum Lp(a) lipoprotein level can cause fetal growth retardation, and it is proposed that very high levels might lead to increased deposition of fibrin in the uterine spiral arteries in pregnancy, which is central in the pathogenesis of pre-eclampsia. If confirmed, a very high Lp(a) lipoprotein level could be one risk factor for pre-eclampsia that is genetically determined.

Gestational changes in nitric oxide synthase activity in the rat placenta

OBJECTIVE

To assess the importance of nitric oxide (NO) generated in the placenta on pregnancy, nitric oxide synthase (NOS) activities were measured in the rat placentas of different gestational ages.

MATERIALS AND METHODS

NOS activity was determined by [3H] L-arginine to [3H]-citrulline conversion assay on rat placenta of day 5, 10, 15 and 21 of gestation.

RESULTS

NOS activity distributed both in the soluble and particulate fractions. Inhibition of NOS activity by L-arginine analogs confirmed the substrate specificity. The requirement of calcium/calmodulin for the maximal activity indicated that the rat placenta NOS was of a constitutive calcium/calmodulin dependent isoform. The activities in both fractions were higher in the earlier gestational age placentas, decreasing with progression of gestation, and the lowest in the term placentas.

CONCLUSION

Although NOS activity was detected in the placenta throughout gestation, it was highest in the early gestational age placenta, suggesting a possible significant role of NO in early gestation.