Cyclooxygenase-1 and -2 in human placenta and placental bed after normal and pre-eclamptic pregnancies

Cellular immune responses in the pathophysiology of preeclampsia

Preeclampsia, defined as new-onset hypertension accompanied by proteinuria occurring at 20 weeks of gestation or later, is a leading cause of perinatal morbidity and mortality worldwide. The pathophysiology of this major multi-systemic syndrome includes defective deep placentation, oxidative stress, endothelial dysfunction, the presence of an anti-angiogenic state, and intravascular inflammation, among others. In this review, we provide a comprehensive overview of the cellular immune responses involved in the pathogenesis of preeclampsia. Specifically, we summarize the role of innate and adaptive immune cells in the maternal circulation, reproductive tissues, and at the maternal-fetal interface of women affected by this pregnancy complication. The major cellular subsets involved in the pathogenesis of preeclampsia are regulatory T cells, effector T cells, NK cells, monocytes, macrophages, and neutrophils. We also summarize the literature on those immune cells that have been less characterized in this clinical condition, such as γδ T cells, invariant natural killer T cells, dendritic cells, mast cells, and B cells. Moreover, we discuss in vivo studies utilizing a variety of animal models of preeclampsia to further support the role of immune cells in this disease. Finally, we highlight the existing gaps in knowledge of the immunobiology of preeclampsia that require further investigation. The goal of this review is to promote translational research leading to clinically relevant strategies that can improve adverse perinatal outcomes resulting from the obstetrical syndrome of preeclampsia.

Maternal vitamin D deficiency influences long-chain polyunsaturated fatty acids and pregnancy outcome in association with alterations in one-carbon metabolism

Preeclampsia is a pregnancy-specific disorder, leading to maternal and infant morbidity and mortality. Abnormal placentation has been reported in preeclampsia. Nutrients like vitamin D and long-chain polyunsaturated fatty acids (LCPUFA) are known to play a role in placental development. In an animal model, we have previously demonstrated that maternal vitamin D deficiency increases the thromboxane/prostacyclin ratio and contributes to inflammation and vasoconstriction. We hypothesize that maternal vitamin D status influences placental LCPUFA metabolism through alterations in one carbon metabolism in women with preeclampsia. To test this hypothesis, we recruited 69 normotensive control (NC) women and 50 women with preeclampsia. Women with preeclampsia had lower placental protein and mRNA levels of cystathionine-β-synthase (CBS), higher plasma malondialdehyde (MDA) levels and higher levels of arachidonic acid (AA) and total omega-6 fatty acids in the placenta. Women with preeclampsia also demonstrated higher placental mRNA levels of cyclooxygenase-2 (COX-2) as compared to NC women. Maternal 25(OH)D levels were negatively associated with maternal plasma MDA levels. Placental vitamin D receptor (VDR) levels were positively associated with CBS while maternal MDA levels were positively associated with serum levels of thromboxane-B2 (TXB2) levels. Our findings indicate that vitamin D deficiency increases oxidative stress through alterations in one carbon metabolism to influence pro-inflammatory omega-6 metabolic pathway in the placenta. This study demonstrates a possible mechanism through which vitamin D deficiency can result in an imbalance in the LCPUFA metabolites and contribute to placental inflammation and endothelial dysfunction in preeclampsia.

MicroRNA‑144‑3p may participate in the pathogenesis of preeclampsia by targeting Cox‑2

Preeclampsia remains a major cause of maternal mortality and morbidity worldwide. It is generally accepted that the development of the placenta, including spiral artery remodelling, normal trophoblast cells function and maternal-fetal inflammation-immune interactions, is critical for the pathogenesis of preeclampsia. Several investigations have demonstrated that microRNAs (miRNAs/miRs) in the placenta may be potential molecular markers for diagnosis of preeclampsia. In the current study, the aim was to investigate the expression of miR-144-3p in the placenta of patients with preeclampsia and normal placentas, and to explore the potential target genes. miRNA microarray analysis was performed using three paired placentas (preeclampsia and normal) in order to find differential expression of miRNAs. Following this, miR-144-3p was selected as a differentially expressed miRNA and validated using in situ hybridization to determine the clinical significance in placentas with preeclampsia. A potential target gene of miR-144-3p, cyclooxygenase-2 (Cox-2), was identified by bioinformatics, luciferase reporter assay and western blotting. The expression of Cox-2 was also examined by immunohistochemical staining of samples of placenta from patients with preeclampsia and normal placenta. Western blot analysis was performed to investigate the effect of miR-144-3p on the expression of Cox-2 in HTR-8/SVneo cells in vitro. miR-144-3p was decreased in placentas from patients with preeclampsia. A luciferase reporter assay demonstrated that Cox-2 was a potential miR-144-3p target gene and the result was verified by western blotting. A negative correlation was observed between miR-144-3p and Cox-2 in preeclamptic placenta by immunohistochemical staining and in situ hybridization. Western blot analysis demonstrated that overexpression of miR-144-3p decreased Cox-2 expression by 38.2% in HTR-8/SVneo cells. Understanding the differential expression of miR-144-3p and its association with Cox-2 may aid the exploration of the pathogenesis of preeclampsia, and contribute to the development of miRNA-based therapies in the future.

The role of α2-adrenergic receptors in hypertensive preeclampsia: A hypothesis

Preeclampsia, a major disorder of human pregnancy, manifests as persistent hypertension and proteinuria presenting after 20 weeks of pregnancy. Multiple systemic symptoms might be associated with preeclampsia including thrombocytopenia, liver impairment, pulmonary edema, and cerebral disturbances. However, vascular dysfunction remains the core pathological driver of preeclampsia. Defective placental implantation followed by dysfunctional placental spiral artery development promotes a hypoxic environment. Massive endothelial dysfunction characterized by reduced vasodilation, augmented vasoconstriction, and increased vascular permeability and inflammation ensues. Interestingly, the same signaling and inflammatory pathways implicated in preeclampsia appear to be shared with other vascular disorders involving alteration of α₂ -AR function. The role of α₂ -ARs in the regulation of microcirculatory function has long been recognized, thus raising the question of whether they are involved in the pathogenesis of vascular dysfunction in preeclampsia. Here, we review possible interplay between signaling and inflammatory pathways common to preeclampsia and α₂ -AR function/regulation. We speculate on the potential contribution of these receptors to the observed phenotype and the potential role for their pharmacological modulators as therapeutic interventions with preeclampsia.

Serum protein marker panel for predicting preeclampsia

BACKGROUND

Preeclampsia is a multi-system disorder in pregnancy which has no effective treatment. The diagnosis of preeclampsia is based on clinical presentation and routine laboratory tests.

OBJECTIVE

This study aimed at identifying serum protein markers for diagnosis of preeclampsia and predicting its severe features.

STUDY DESIGN

In total, 172 pregnant women were enrolled in this study including 110 subjects with preeclampsia and 62 normotensive subjects. Eleven serum proteins (VEGF, sFlt-1, sEndoglin, PlGF, sEGFR, prolactin, PTX3, PAI-1, NGAL, IL-27, COX-2) were assessed using Luminex multiplex immunoassay and ELISA.

RESULTS

The levels of seven proteins (sFlt-1, VEGF, sEndoglin, sEGFR, PlGF, NGAL, COX-2) correlated with preeclampsia, and 4 proteins (VEGF, sEndoglin, PlGF, sEGFR) were identified as independent factors associated with preeclampsia. The levels of three proteins (sEndoglin, PTX3, sFlt-1) correlated with severe features of preeclampsia, and three variables (serum creatinine, platelet count and sEndoglin) were identified as independent factors in predicting severe features of preeclampsia.

CONCLUSIONS

A combination of serum protein markers (VEGF, sEndoglin, PlGF, sEGFR) and clinical variables (serum creatinine, platelet count and sEndoglin) could be used as analytical tool in diagnosis of preeclampsia and its severe features, respectively. Serum sEGFR, a novel biomarker in preeclampsia, may be involved in the pathogenesis of preeclampsia.

Selective Targeting of a Novel Vasodilator to the Uterine Vasculature to Treat Impaired Uteroplacental Perfusion in Pregnancy

Fetal growth restriction (FGR) in pregnancy is commonly caused by impaired uteroplacental blood flow. Vasodilators enhance uteroplacental perfusion and fetal growth in humans and animal models; however, detrimental maternal and fetal side effects have been reported. We hypothesised that targeted uteroplacental delivery of a vasodilator would enhance drug efficacy and reduce the risks associated with drug administration in pregnancy. Phage screening identified novel peptides that selectively accumulated in the uteroplacental vasculature of pregnant mice. Following intravenous injection, the synthetic peptide CNKGLRNK selectively bound to the endothelium of the uterine spiral arteries and placental labyrinth in vivo; CNKGLRNK-decorated liposomes also selectively bound to these regions. The nitric oxide donor 2-[[4-[(nitrooxy)methyl]benzoyl]thio]-benzoic acid methyl ester (SE175) induced significant relaxation of mouse uterine arteries and human placental arteries in vitro; thus, SE175 was encapsulated into these targeted liposomes and administered to healthy pregnant C57BL/6J mice or endothelial nitric oxide synthase knockout (eNOS-/-) mice, which exhibit impaired uteroplacental blood flow and FGR. Liposomes containing SE175 (0.44mg/kg) or PBS were administered on embryonic (E) days 11.5, 13.5, 15.5 and 17.5; fetal and placental weights were recorded at term and compared to mice injected with free PBS or SE175. Targeted uteroplacental delivery of SE175 had no effect on fetal weight in C57BL/6J mice, but significantly increased fetal weight and mean spiral artery diameter, and decreased placental weight, indicative of improved placental efficiency, in eNOS-/- mice; free SE175 had no effect on fetal weight or spiral artery diameter. Targeted, but not free SE175 also significantly reduced placental expression of 4-hydroxynonenal, cyclooxygenase-1 and cyclooxygenase-2, indicating a reduction in placental oxidative stress. These data suggest that exploiting vascular targeting peptides to selectively deliver SE175 to the uteroplacental vasculature may represent a novel treatment for FGR resulting from impaired uteroplacental perfusion.

Sphingolipids as a new factor in the pathomechanism of preeclampsia - Mass spectrometry analysis

Objective(s) and design

The aim of the study was to analyse a panel of 11 sphingolipids in plasma and three blood fractions (platelet-poor plasma, platelets and red blood cells) of women with mild preeclampsia.

Materials and methods

We recruited 21 women between 25–40 weeks gestation with diagnosed mild preeclampsia to the study group and 36 healthy women with uncomplicated pregnancies, who corresponded with the study group according to gestational age, to the control group. To assess the concentration of 11 sphingolipids in the blood plasma and blood fractions, we used ultra-high performance liquid chromatography coupled with triple quadrupole mass spectrometry (UHPLC/MS/MS).

Results

We showed a significant increase in the concentration of eight sphingolipids in the plasma of women with preeclampsia in comparison to the control group: Sph (p = 0.0032), S1P (p = 0.0289), C20-Cer (p < 0.0001), C18-Cer (p < 0.0001), C16-Cer (p = 0.012), C18:1-Cer (p = 0.003), C22-Cer (p = 0.0071), and C24:1-Cer (p = 0.0085).

Conclusion

We showed that selected sphingolipids, especially C20-Cer and C18-Cer, are totally new factors in the pathomechanism of PE and that these bioactive lipids may play an important role in apoptosis and autophagy.

Alterations in eicosanoid composition during embryonic development in the chorioallantoic membrane of the American alligator (Alligator mississippiensis) and domestic chicken (Gallus gallus)

Eicosanoids are signaling lipids known to regulate several physiological processes in the mammalian placenta, including the initiation of parturition. Though all amniotes construct similar extraembryonic membranes during development, the composition and function of eicosanoids in extraembryonic membranes of oviparous reptiles is largely unknown. The majority of effort placed in eicosanoid investigations is typically targeted toward defining the role of specific compounds in disease etiology; however, comprehensive characterization of several pathways in eicosanoid synthesis during development is also needed to better understand the complex role of these lipids in comparative species. To this end, we have examined the chorioallantoic membrane (CAM) of the American alligator (Alligator mississippiensis) and domestic chicken (Gallus gallus) during development. Previously, our lab has demonstrated that the CAM of several oviparous species shared conserved steroidogenic activity, a feature originally attributed to mammalian amniotes. To further explore this, we have developed a liquid chromatography/tandem mass spectrometry method that is used here to quantify multiple eicosanoids in the CAM of two oviparous species at different stages of development. We identified 18 eicosanoids in the alligator CAM; the cyclooxygenase (COX) pathway showed the largest increase from early development to later development in the alligator CAM. Similarly, the chicken CAM had an increase in COX products and COX activity, which supports the LC-MS/MS analyses. Jointly, our findings indicate that the CAM tissue of an oviparous species is capable of eicosanoid synthesis, which expands our knowledge of placental evolution and introduces the possibility of future comparative models of placental function.

Reduced Maternal Erythrocyte Long Chain Polyunsaturated Fatty Acids Exist in Early Pregnancy in Preeclampsia

The present prospective study examines proportions of maternal erythrocyte fatty acids across gestation and their association with cord erythrocyte fatty acids in normotensive control (NC) and preeclamptic pregnancies. We hypothesize that maternal fatty acid status in early pregnancy influences fetal fatty acid stores in preeclampsia. 137 NC women and 58 women with preeclampsia were included in this study. Maternal blood was collected at 3 time points during pregnancy (16-20th weeks, 26-30th weeks and at delivery). Cord blood was collected at delivery. Fatty acids were analyzed using gas chromatography. The proportions of maternal erythrocyte α-linolenic acid, docosahexaenoic acid, nervonic acid, and monounsaturated fatty acids (MUFA) (p < 0.05 for all) were lower while total n-6 fatty acids were higher (p < 0.05) at 16-20th weeks of gestation in preeclampsia as compared with NC. Cord 18:3n-3, 22:6n-3, 24:1n-9, MUFA, and total n-3 fatty acids (p < 0.05 for all) were also lower in preeclampsia as compared with NC. A positive association was observed between maternal erythrocyte 22:6n-3 and 24:1n-9 at 16-20th weeks with the same fatty acids in cord erythrocytes (p < 0.05 for both) in preeclampsia. Our study for the first time indicates alteration in maternal erythrocyte fatty acids at 16th weeks of gestation which is further reflected in cord erythrocytes at delivery in preeclampsia.

Gestation Related Gene Expression of the Endocannabinoid Pathway in Rat Placenta

Mammalian placentation is a vital facet of the development of a healthy and viable offspring. Throughout gestation the placenta changes to accommodate, provide for, and meet the demands of a growing fetus. Gestational gene expression is a crucial part of placenta development. The endocannabinoid pathway is activated in the placenta and decidual tissues throughout pregnancy and aberrant endocannabinoid signaling during the period of placental development has been associated with pregnancy disorders. In this study, the gene expression of eight endocannabinoid system enzymes was investigated throughout gestation. Rat placentae were obtained at E14.25, E15.25, E17.25, and E20, RNA was extracted, and microarray was performed. Gene expression of enzymes Faah, Mgll, Plcd4, Pld1, Nat1, Daglα, and Ptgs2 was studied (cohort 1, microarray). Biological replication of the results was performed by qPCR (cohort 2). Four genes showed differential expression (Mgll, Plcd4, Ptgs2, and Pld1), from mid to late gestation. Genes positively associated with gestational age were Ptgs2, Mgll, and Pld1, while Plcd4 was downregulated. This is the first comprehensive study that has investigated endocannabinoid pathway gene expression during rat pregnancy. This study provides the framework for future studies that investigate the role of endocannabinoid system during pregnancy.

Mono-ethylhexyl phthalate stimulates prostaglandin secretion in human placental macrophages and THP-1 cells

BACKGROUND

Diethylhexyl phthalate (DEHP) is widely used as a plasticizer in polyvinyl chloride products. DEHP exposure, which is widespread in the US, increases preterm birth risk; however, the mechanisms driving this relationship are unclear. Because cyclooxygenase-2 (COX-2) dependent prostaglandin synthesis is implicated in preterm birth, we evaluated effects of mono-2-ethylhexyl phthalate (MEHP), the active metabolite of DEHP, on prostaglandin E2 (PGE2) synthesis and COX expression in human placental macrophages (PM). In addition, responses in PM were compared to those in a human macrophage-like cell line, THP-1.

METHODS

PM and THP-1 cells were treated for 2, 4, 8, or 24 h with MEHP concentrations ranging from 10 to 180 micromolar. PGE2 concentrations were assessed in culture medium using ELISA, and COX expression was determined by western blot.

RESULTS

Treatment of PM and THP-1 cells with 180 micromolar MEHP for 24 h significantly increased PGE2 release. Co-treatment of PMs or THP-1 cells with 180 micromolar MEHP and the non-selective COX inhibitor indomethacin reduced MEHP-stimulated PGE2 production. Similarly, co-treatment of PM and THP-1 cells with the COX-2 selective inhibitor NS-398 resulted in a significant decrease in PGE2, suggesting that MEHP-stimulated PGE2 is dependent specifically on increased COX-2 expression. Western blot analysis revealed a significant increase in COX-2 expression in PM and THP-1 cells treated with 180 micromolar MEHP, and no changes in COX-1 expression, supporting the role of COX-2 in MEHP-stimulated PGE2 synthesis.

CONCLUSIONS

The findings from this study are the first to demonstrate phthalate-stimulated PGE2 synthesis in PM and warrant future studies into COX-2-dependent prostaglandin synthesis as a mechanism of toxicant-associated preterm birth.

Aspirin inhibits expression of sFLT1 from human cytotrophoblasts induced by hypoxia, via cyclo-oxygenase 1

INTRODUCTION

Elevated circulating soluble FLT1 (sFLT1) levels seen in preeclampsia may play a role in its development. Aspirin is recommended for prevention of preeclampsia. We hypothesized that aspirin may inhibit the production of sFlt1.

METHODS

Placentas from women with and without preeclampsia were collected. Primary cytotrophoblasts (CTBs) were cultured from normal placentas and treated with aspirin, sc-560, a COX1 inhibitor or celecoxib, a COX2 inhibitor. The expression of sFLT1, FLT1, COX1 and COX2 was studied. The effect of aspirin on sFlt1 expression was also studied in HEK293 cells and in HTR-8/SVNeo cells.

RESULTS

The expression of sFLT1 was increased in preeclamptic placentas compared to control placentas and the expression and release of sFLT1 increased in CTBs exposed to 2% O2 compared to controls. Aspirin at 3 and 12 mM concentration reduced the expression and release of sFLT1 in CTBs. Aspirin also inhibited sFlt1 expression from HTR-8/SVNeo and HEK293 cells. Sc-560, but not celecoxib, reduced sFLT1 expression and release from CTBs. Aspirin and sc-560 also reduced hypoxia-induced FLT1 mRNA expression and inhibited COX1 mRNA in CTBs.

DISCUSSION

This study confirms that sFLT1 expression is increased in preeclamptic placentas and in CTBs exposed to hypoxia. Aspirin inhibits the production sFLT1 in CTBs and in HTR-8/SVNeo. Sc-560 recapitulated the effects of aspirin on sFLT1 expression and release in CTBs suggesting that the aspirin effect may be mediated via inhibition of COX1. The study increases our understanding of the mechanisms regulating sFlt1 expression and provides a plausible explanation for the effect of aspirin to prevent preeclampsia.

Prostaglandin pathway gene expression in human placenta, amnion and choriodecidua is differentially affected by preterm and term labour and by uterine inflammation

Background

Elucidation of the biochemical pathways involved in activation of preterm and term human labour would facilitate the development of effective management and inform judgements regarding the necessity for preterm tocolysis and post-term induction. Prostaglandins act at all stages of human reproduction, and are potentially activators of labour.

Methods

Expression of 15 genes involved in prostaglandin synthesis, transport and degradation was measured by qPCR using tissue samples from human placenta, amnion and choriodecidua at preterm and full-term vaginal and caesarean delivery. Cellular localisation of eight prostaglandin pathway proteins was determined by immunohistochemistry.

Results

Expression of prostaglandin pathway genes was differentially affected by factors including gestational age at delivery, and the incidence and duration of labour. Chorioamnionitis/deciduitis was associated with upregulation of PTGS2 (prostaglandin-endoperoxide synthase 2 (prostaglandin G/H synthase and cyclooxygenase)), along with the inflammatory genes IL8 (interleukin 8), S100A8 (S100 calcium binding protein A8) and TLR2 (toll-like receptor 2), in amnion and choriodecidua, and with downregulation of CBR1 (carbonyl reductase 1) and HPGD (hydroxyprostaglandin dehydrogenase 15-(NAD)) in choriodecidua. Protein localisation differed greatly between the various maternal and fetal cell types.

Conclusions

Preterm and term labour are associated with distinct prostaglandin pathway expression profiles; inflammation provokes specific changes, unrelated to the presence of labour; spontaneous and induced term labour are indistinguishable.

Maternal high-fat diet alters expression of pathways of growth, blood supply and arachidonic acid in rat placenta

The high fat content in Western diets probably affects placental function during pregnancy with potential consequences for the offspring in the short and long term. The aim of the present study was to compare genome-wide placental gene expression between rat dams fed a high-fat diet (HFD) and those fed a control diet for 3 weeks before conception and during gestation. Gene expression was measured by microarray and pathway analysis was performed. Gene expression differences were replicated by real-time PCR and protein expression was assessed by Western blot analysis. Placental and fetal weights at E17.25 were not altered by exposure to the maternal HFD. Gene pathways targeting placental growth, blood supply and chemokine signalling were up-regulated in the placentae of dams fed the HFD. The up-regulation in messenger RNA expression for five genes Ptgs2 (fatty acid cyclo-oxidase 2; COX2), Limk1 (LIM domain kinase 1), Pla2g2a (phospholipase A2), Itga1 (integrin α-1) and Serpine1 was confirmed by real-time PCR. Placental protein expression for COX2 and LIMK was also increased in HFD-fed dams. In conclusion, maternal HFD feeding alters placental gene expression patterns of placental growth and blood supply and specifically increases the expression of genes involved in arachidonic acid and PG metabolism. These changes indicate a placental response to the altered maternal metabolic environment.

Expression levels of cyclooxygenase-2, tumor necrosis factor-α and inducible NO synthase in placental tissue of normal and preeclamptic pregnancies

OBJECTIVE

Although preeclampsia (PE) is one of the most important problems affecting pregnant women, etiologic factors in its development are still unclear. We aimed to investigate the expression levels of cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α) and inducible NO synthase (iNOS) in preeclamptic and healthy control placentas.

PATIENTS AND METHODS

Placental tissue samples were obtained after delivery from patients diagnosed with PE and from normal-term pregnants and analyzed for COX-2, TNF-α and iNOS expression by immunohistochemistry.

RESULTS

A strong expression of COX-2 was observed in syncytiotrophoblast cells of preeclamptic placentas, which was significantly higher than that of normal placentas (p = 0.005). A mild expression of TNF-α in both normal and preeclamptic syncytiotrophoblasts was seen (p = 0.435). In addition, a strong expression of iNOS in normal syncytiotrophoblasts was found, but the intensity of the iNOS expression was highly reduced in preeclamptic placentas (p = 0.001). No correlation was detected between COX-2, TNF-α and iNOS expression levels.

CONCLUSION

The findings of a decrease of iNOS expression and an increase of COX-2 expression in placenta suggest the existence of functional roles of iNOS and COX-2 in the pathophysiology of PE, probably by contributing to the reduced placental blood flow and increased resistance to flow in the fetomaternal circulation.

Challenges posed to the maternal circulation by pregnancy

In primates, adequate growth of the fetus depends on the development of the uteroplacental unit. On the fetal side, this is achieved by the creation of the vascular network of the placenta. On the maternal side, the transformation of the spiral arteries into saccular nonreactive vessels by the trophoblast provides high blood flow to the intervillous space. Apart from the changes in the uterine arteries, the mother expands her plasma volume – at the expense of stimulating the renin-angiotensin-aldosterone system – and her cardiac output. In the maintaining of normotension in the face of an increased cardiac output and plasma volume, the renin-angiotensin-aldosterone system requires an enhanced vasodilator synthesis. Finally, in the late stages of pregnancy, a normal endothelial function is required to provide an ample margin to the activation provoked by deportation of syncytiotrophoblast fragments/factors to the maternal circulation. These four adaptative processes require various interrelated vasodilator systems. Deficient adaptations cause isolated or proteinuric arterial hypertension, intrauterine growth restriction, preterm delivery, and stillbirths, among others. Moreover, a normal or a defective adaptation to pregnancy influences maternal cardiovascular health in later life, as evidenced by various studies, most of them epidemiological; thus, pregnancy is now considered a stress test to the maternal cardiovascular system. Because of this, women planning to become pregnant should be screened for clinical and biochemical cardiovascular risks. Inversely, women presenting with hypertension in pregnancy should be thoroughly studied to detect and correct cardiovascular risks. The incorporation of the predictive value of a hypertensive pregnancy should help reduce cardiovascular disease in women.

Examination of the expression of cyclooxygenase-2 in placenta villi from sufferers of pregnancy induced hypertension

OBJECTIVES

The purpose of this paper is to elucidate the roles of phospholipase A(2) (PLA(2)), cyclooxygenase-2 (COX-2), and prostaglandin I(2) (PGI(2)) synthase in pregnancy induced hypertension (PIH).

METHODS

In placentas from normal pregnant women and pregnant women with severe PIH, the enzyme expression of PLA(2), COX-2, and PGI(2) synthase was measured using real time reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

The expression of each enzyme was compared between normal (n=12) and PIH (n=12) groups. The expression levels of COX-2 and PGI(2) synthase during PIH pregnancy were significantly decreased to about 51% and 68%, respectively, of their values in normal pregnancy. However, the expression of PLA(2) was hardly changed by PIH.

CONCLUSIONS

The decreases in COX-2 and PGI(2) synthase expression in severe PIH placentas may be causal factors in the disruption of the PGI(2)-thromboxane A(2) (TXA(2)) balance in favor of TXA(2). The decrease in COX-2 was more marked than that of PGI(2) synthase.

Chronic infection during placental malaria is associated with up-regulation of cycloxygenase-2

BACKGROUND

Placental malaria (PM) is associated with poor foetal development, but the pathophysiological processes involved are poorly understood. Cyclooxygenase (COX) and lipoxygenase (LOX) which convert fatty acids to prostaglandins and leukotrienes, play important roles in pregnancy and foetal development. COX-2, currently targeted by specific drugs, plays a dual role as it associates with both pre-eclampsia pathology and recovery during infection. The role of COX during PM was questioned by quantifying at delivery COX-1, COX-2, 15-LOX, and IL-10 expression in two groups of malaria infected and uninfected placenta.

METHODS

Placental biopsies were collected at delivery for mRNA isolation and quantification, using real time PCR.

RESULTS

COX-2 and IL-10 mRNAs increased mainly during chronic infections (nine- and five-times, respectively), whereas COX-1 transcripts remained constant. COX-2 over-expression was associated with a higher birth weight of the baby, but with a lower rate of haemoglobin of the mother. It was associated with a macrophage infiltration of the placenta and with a low haemozoin infiltration. In the opposite way, placental infection was associated with lower expression of 15-LOX mRNA. A high degree of haemozoin deposition correlates with low birth weight and decreased expression of COX-2.

CONCLUSION

These data provide evidence that COX-2 and IL-10 are highly induced during chronic infection of the placenta, but were not associated with preterm delivery or low birth weight. The data support the involvement of COX-2 in the recovery phase of the placental infection.

Maternal and fetal fatty acid profile in normal and intrauterine growth restriction pregnancies with and without preeclampsia

The aim of this study was to evaluate maternal and fetal lipid profile in intrauterine growth restriction (IUGR) pregnancies with and without preeclampsia (PE). Thirteen normal pregnancies studied during the third trimester (control M) and 29 at elective cesarean section (control CS) were compared with 18 pregnancies complicated by IUGR (IUGR only) and with seven pregnancies complicated by both IUGR and PE (IUGR-PE). Total plasma fatty acids, triglycerides, cholesterol, and nonesterified fatty acids (NEFA) were determined in maternal and fetal plasma. Nutritional intake was analyzed. IUGR only mothers had lower percentage of linoleic acid (LA) and higher arachidonic acid (AA) than controls, partly explained by higher AA dietary intake. Higher levels of NEFA were observed both in IUGR only and in IUGR-PE mothers whereas triglyceride levels were increased in IUGR-PE mothers only. In IUGR-PE fetuses, LA and AA were significantly decreased, whereas triglyceride and NEFA concentrations were significantly increased compared with normal fetuses. In conclusion, IUGR only is associated with altered fatty acids profile not completely accounted by dietary changes. We hypothesize that the differences observed in IUGR with PE for triglycerides and other lipids could be related to a difference in maternal phenotype.

Placental tissue cyclo-oxygenase 1 and 2 in pre-eclamptic and normal pregnancy

OBJECTIVE

To investigate the activities of the 2 isoforms of prostaglandin synthetic enzyme cyclo-oxygenase (COX), COX-1 and COX-2, in the placental tissue of women with pre-eclampsia and healthy pregnant women. The relationship between placental lipid peroxidation and the activities of COX-1 and COX-2 was also investigated.

METHODS

Tissue specimens were obtained from pre-eclamptic women (20 had severe pre-eclampsia and 38 had mild pre-eclampsia) and 27 healthy pregnant women who underwent cesarean section before the onset of labor. Malondialdehyde (MDA) levels and COX-1 and COX-2 activities were measured in placental tissue homogenates.

RESULTS

Mean activities for COX-1 and COX-2 were significantly lower in women with severe pre-eclampsia than in healthy controls (P<0.05 and P<0.01, respectively). COX-1 and COX-2 activities were also lower in women with mild pre-eclampsia than in healthy controls, but the difference was of borderline significance (P=0.049 and P=0.059, respectively). The mean placental MDA level was significantly higher in pregnant women with severe and mild pre-eclampsia than in healthy pregnant women (P<0.01 for both). The correlation analysis showed significant negative correlations between MDA and COX-1 (r=-0.44, P<0.001) and MDA and COX-2 (r=-0.45, P<0.001) in the placental tissue of women with pre-eclampsia.

CONCLUSION

These results suggest that COX-1 and COX-2 activities are decreased in the placental tissue of women with pre-eclampsia, probably by oxidative stress.

Animal models of implantation

Implantation is an intricately timed event necessary in the process of viviparous birth that allows mammals to nourish and protect their young during early development. Human implantation begins when the blastocyst both assumes a fixed position in the uterus and establishes a more intimate relationship with the endometrium. Due to the impracticalities of studying implantation in humans, animal models are necessary to decipher the molecular and mechanical events of this process. This review will discuss the differences in implantation between different animal models and describe how these differences can be utilized to investigate discrete implantation stages. In addition, factors that have been shown to be involved in implantation in the human and other various animal models including growth factors, cytokines, modulators of cell adhesion, and developmental factors will be discussed, and examples from each will be given.

Reciprocal expression of peroxisome proliferator-activated receptor-gamma and cyclooxygenase-2 in human term parturition

OBJECTIVE

The objective of this study was to test the hypothesis that peroxisome proliferator activated receptor-gamma (PPAR-gamma) is expressed in intrauterine tissues before active term human parturition, and that its repression is associated with up-regulation of cyclooxygenase-2 (COX-2).

STUDY DESIGN

Specimens were collected from women with term singleton pregnancies after spontaneous labor or cesarean section before labor, prepared for immunoblot and immunohistochemical analysis, and probed for PPAR-gamma or COX-2.

RESULTS

PPAR-gamma expression was prominent in fetal membranes and placenta before active labor. After labor, PPAR-gamma expression was significantly reduced in fetal membranes, but not in placenta. The ratio of COX-2:PPAR-gamma was significantly elevated in fetal membranes with labor. PPAR-gamma immunostaining was prominent in syncytiotrophoblast, extravillous cytotrophoblasts, and cells of the amnion and chorion. COX-2 immunostaining was abundant in the amnion and rare in the placenta.

CONCLUSION

PPAR-gamma is highly expressed in term intrauterine tissues. In fetal membranes, PPAR-gamma levels are reduced once active labor commences, coincidental with a relative increase in COX-2 expression.

COX-2 inhibitors and their role in gynecology

This review summarizes current knowledge about the roles of cyclooxygenases and prostaglandins in reproductive medicine. With the development of COX-2 specific inhibitors, new therapeutic options are available to obstetricians and gynecologists, offering better-tolerated alternatives to conventional NSAIDs. The analgesic effectiveness of COX-2 specific inhibitors is well established, and they are already in use in a range of painful conditions. Both celecoxib and valdecoxib are indicated for the treatment of primary dysmenorrhea, and may be effective in postoperative pain, including hysterectomy, and pain associated with endometriosis. There is also speculation that COX-2 specific inhibitors may be effective tocolytic agents without the risks to the fetus seen with conventional NSAIDs. The role of COX-2 in oncogenesis is also under investigation, and COX-2 specific inhibitors may eventually be used in the prevention and treatment of gynecologic malignancies.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians Learning Objectives: After completion of this article, the reader will be able to describe the two types of cylooxygenase enzymes (COX), to list the effects and side effects of NSAIDs and COX-2 medications, and to outline the various changes in COX expression during pregnancy.

Distribution of cyclooxygenase-2 in eutopic and ectopic endometrium in endometriosis and adenomyosis

The objective of this study was to determine the distribution of cyclooxygenase-2 (COX-2) in eutopic and ectopic endometria in endometriosis and adenomyosis. The subjects were 35 patients with endometriosis diagnosed by laparoscopy, 33 patients with histologically confirmed adenomyosis and 50 female controls with normal fecundity. Expression of COX-2 was immunohistochemically investigated in tissues from eutopic endometrium and myometrium and ectopic endometrium of the wall of ovarian chocolate cysts using polyclonal antibody. Surface epithelial cells, endometrial glandular epithelial cells or stromal cells were assessed. Cells were semi-quantitatively assessed on a scale of 1 to 5 using a nomogram created from positive cell count and the degree of staining. COX-2 expression in surface and glandular epithelia of the control group varied markedly during the menstrual cycle. It was lowest in the early proliferative phase and gradually increased thereafter. It remained high throughout the secretory phase. However, in patients with endometriosis, expression of COX-2 in glandular epithelium was higher than that in the control group, though it varied throughout the menstrual cycle. On the other hand, there was no variation in expression of COX-2 in the adenomyosis group during the menstrual cycle, and it was lower than that in the endometriosis group in all phases. Pronounced COX-2 expression was observed in glandular cells from ectopic endometrial tissue of ovarian chocolate cyst walls in all cases regardless of the menstrual phase. In summary, increased COX-2 expression in eutopic and ectopic endometria was believed to be strongly correlated with pathological abnormalities in these disorders.

High cyclooxygenase-2 expression in stage IB cervical cancer with lymph node metastasis or parametrial invasion

OBJECTIVE

The enzymes cyclooxygenase (COX)-1 and -2 are necessary for the synthesis of prostaglandins. COX-2 is usually absent in normal cells and is upregulated and expressed as a product of the "immediate early" gene during inflammatory processes. In previous studies, the expression of COX-2 has been shown to be induced by proinflammatory cytokines, and suggestions have been made that overexpression of COX-2 suppresses apoptosis and is directly related to tumor growth. We have attempted to determine a relationship between tumor invasion and metastasis of uterine cervical cancer and COX and apoptosis by comparing the protein expression of apoptosis, COX-1, and COX-2 in tumor tissues.

METHODS

The subjects were 36 patients who were FIGO stage IB uterine cervical cancer patients who underwent surgery at Ajou University Hospital. There were 12 cases with lymph node or parametrial involvement. All tissues were subjected to immunohistochemical staining for COX-1, -2, and TUNEL method for apoptosis detection, and the following results were obtained.

RESULTS

Tumor tissues confirmed by cytokeratin were separated into tumor surface, tumor stroma, and invasion site portions, in which decreased apoptosis was observed in the invasion sites. COX-2 expression was observed in all tumor tissues and was especially strong in the tumor invasion site. Therefore, it is suggested that COX-2 expression may suppress cell apoptosis at the tumor invasion site. When COX-2 expression was investigated according to the groups with regard to the presence of lymph node or parametrial involvement, there was a statistically significant (Mann-Whitney U test) COX-2 expression difference in the tumor invasion site (P value = 0.040) and the tumor stroma (P value = 0. 028).

CONCLUSIONS

In surgically treated stage IB cervical cancer patients, COX-2 was significantly expressed when lymph node or parametrial involvement was present. These results suggest that the expression of COX-2 in stage IB cervical cancer may downregulate apoptotic processes and thus enhance tumor invasion and metastasis.

Studies on the HLA-DRB1 genotypes in Japanese women with severe pre-eclampsia positive and negative for anticardiolipin antibody using a polymerase chain reaction-restriction fragment length polymorphism method

The human leukocyte antigen (HLA)-DR genotype was determined in 54 Japanese women with severe pre-eclampsia in order to elucidate the relationship between HLA-DR antigen systems and pre-eclampsia. The patients were divided into two groups according to positivity for the anticardiolipin antibody (ACA), i.e. one patient group negative for ACA (n = 41) and the other patient group positive for ACA (n = 13). The frequency of each HLA-DRB1 allele in both groups was compared with that in 81 normally fertile Japanese women who had not experienced pre-eclampsia. The genotypes of HLA-DR antigens were determined using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The frequency of DRB1*04 and DRB1*0403 in the patient group positive for the ACA was significantly higher compared with that in the group of normal fertile women (P< 0.05). The frequency of each HLA-DRB1 allele was not significantly different between patient group with pre-eclampsia negative for ACA and group of normal fertile women. These results suggest a difference in the immunogenetic background between the patient groups with severe pre-eclampsia positive and negative for the ACA.

Requirement of nuclear factor kappaB for the constitutive expression of nitric oxide synthase-2 and cyclooxygenase-2 in rat trophoblasts

Recently isolated trophoblasts express nitric oxide synthase 2 (NOS-2) and cyclooxygenase 2 (COX-2), decreasing the levels of the corresponding mRNAs when the cells were maintained in culture. The sustained expression of COX-2 and NOS-2 in trophoblasts was dependent on the activation of nuclear factor kappaB (NF-kappaB) since proteasome inhibitors and antioxidants that abrogated NF-kappaB activity suppressed the induction of both genes. The time-dependent fall of the mRNA levels of NOS-2 and COX-2 paralleled the inhibition of NF-kappaB, determined by electrophoretic mobility shift assays, and the increase of the IkappaBalpha and IkappaBbeta inhibitory proteins. Isolated trophoblasts synthesized reactive oxygen intermediates (ROI), a process impaired after culturing the cells, and that might be involved in the NF-kappaB activation process. Moreover, treatment of recently isolated cells with ROI scavengers suppressed the expression of COX-2 and NOS-2. Challenge of trophoblasts with interleukin-1beta up-regulated the expression of both proteins, an effect that was potentiated by lipopolysaccharide. These results indicate that the physiological expression of NOS-2 and COX-2 in trophoblasts involves a sustained activation of NF-kappaB which inhibition abrogates the inducibility of both genes.