Association between the maternal serum levels of 19 eicosanoids and pre-eclampsia

Associations of maternal blood metal concentrations with plasma eicosanoids among pregnant women in Puerto Rico

BACKGROUND/AIM

Heavy metals are known to induce oxidative stress and inflammation, and the association between metal exposure and adverse birth outcomes is well established. However, there lacks research on biomarker profiles linking metal exposures and adverse birth outcomes. Eicosanoids are lipid molecules that regulate inflammation in the body, and there is growing evidence that suggests associations between plasma eicosanoids and pregnancy outcomes. Eicosanoids may aid our understanding of etiologic birth pathways. Here, we assessed associations between maternal blood metal concentrations with eicosanoid profiles among 654 pregnant women in the Puerto Rico PROTECT birth cohort.

METHODS

We measured concentrations of 11 metals in whole blood collected at median 18 and 26 weeks of pregnancy, and eicosanoid profiles measured in plasma collected at median 26 weeks. Multivariable linear models were used to regress eicosanoids on metals concentrations. Effect modification by infant sex was explored using interaction terms.

RESULTS

A total of 55 eicosanoids were profiled. Notably, 12-oxoeicosatetraenoic acid (12-oxoETE) and 15-oxoeicosatetraenoic acid (15-oxoETE), both of which exert inflammatory activities, had the greatest number of significant associations with metal concentrations. These eicosanoids were associated with increased concentrations of Cu, Mn, and Zn, and decreased concentrations of Cd, Co, Ni, and Pb, with the strongest effect sizes observed for 12-oxoETE and Pb (β:-33.5,95 %CI:-42.9,-22.6) and 15-oxoETE and Sn (β:43.2,95 %CI:11.4,84.1). Also, we observed differences in metals-eicosanoid associations by infant sex. Particularly, Cs and Mn had the most infant sex-specific significant associations with eicosanoids, which were primarily driven by female fetuses. All significant sex-specific associations with Cs were inverse among females, while significant sex-specific associations with Mn among females were positive within the cyclooxygenase group but inverse among the lipoxygenase group.

CONCLUSION

Certain metals were significantly associated with eicosanoids that are responsible for regulating inflammatory responses. Eicosanoid-metal associations may suggest a role for eicosanoids in mediating metal-induced adverse birth outcomes.

Bioactive lipid mediators in plasma are predictors of preeclampsia irrespective of aspirin therapy

There are few early biomarkers to identify pregnancies at risk of preeclampsia (PE) and abnormal placental function. In this cross-sectional study, we utilized targeted ultra-performance liquid chromatography-ESI MS/MS and a linear regression model to identify specific bioactive lipids that serve as early predictors of PE. Plasma samples were collected from 57 pregnant women prior to 24-weeks of gestation with outcomes of either PE (n = 26) or uncomplicated term pregnancies (n = 31), and the profiles of eicosanoids and sphingolipids were evaluated. Significant differences were revealed in the eicosanoid, (±)11,12 DHET, as well as multiple classes of sphingolipids; ceramides, ceramide-1-phosphate, sphingomyelin, and monohexosylceramides; all of which were associated with the subsequent development of PE regardless of aspirin therapy. Profiles of these bioactive lipids were found to vary based on self-designated race. Additional analyses demonstrated that PE patients can be stratified based on the lipid profile as to PE with a preterm birth linked to significant differences in the levels of 12-HETE, 15-HETE, and resolvin D1. Furthermore, subjects referred to a high-risk OB/GYN clinic had higher levels of 20-HETE, arachidonic acid, and Resolvin D1 versus subjects recruited from a routine, general OB/GYN clinic. Overall, this study shows that quantitative changes in plasma bioactive lipids detected by ultra-performance liquid chromatography-ESI-MS/MS can serve as an early predictor of PE and stratify pregnant people for PE type and risk.

Targeted and untargeted metabolomic approach for GDM diagnosis

Gestational diabetes mellitus (GDM) is a disorder which manifests itself for the first time during pregnancy and is mainly connected with glucose metabolism. It is also known that fatty acid profile changes in erythrocyte membranes and plasma could be associated with obesity and insulin resistance. These factors can lead to the development of diabetes. In the reported study, we applied the untargeted analysis of plasma in GDM against standard glucose-tolerant (NGT) women to identify the differences in metabolomic profiles between those groups. We found higher levels of 2-hydroxybutyric and 3-hydroxybutyric acids. Both secondary metabolites are associated with impaired glucose metabolism. However, they are products of different metabolic pathways. Additionally, we applied lipidomic profiling using gas chromatography to examine the fatty acid composition of cholesteryl esters in the plasma of GDM patients. Among the 14 measured fatty acids characterizing the representative plasma lipidomic cluster, myristic, oleic, arachidonic, and α-linoleic acids revealed statistically significant changes. Concentrations of both myristic acid, one of the saturated fatty acids (SFAs), and oleic acid, which belong to monounsaturated fatty acids (MUFAs), tend to decrease in GDM patients. In the case of polyunsaturated fatty acids (PUFAs), some of them tend to increase (e.g., arachidonic), and some of them tend to decrease (e.g., α-linolenic). Based on our results, we postulate the importance of hydroxybutyric acid derivatives, cholesteryl ester composition, and the oleic acid diminution in the pathophysiology of GDM. There are some evidence suggests that the oleic acid can have the protective role in diabetes onset. However, metabolic alterations that lead to the onset of GDM are complex; therefore, further studies are needed to confirm our observations.

Functional and pathological role of 15-Lipoxygenase and its metabolites in pregnancy and pregnancy-associated complications

Maternal lipid metabolism status during pregnancy may have pivotal effects on a healthy pregnancy, the progression of labor, and childbirth. Based on evidence, changes in maternal lipid profile and metabolism is related to various alterations in fetal metabolic status, fat mass, birth weight and can result in serious maternal and fetal complications. 15-lipoxygenase accounts as a key enzyme in metabolizing polyunsaturated fatty acids that generate various inflammatory lipid metabolites. The possible involvement of 15- lipoxygenase and its metabolites in the inflammatory process, cell proliferation and death, and immune response has been postulated. The indicative role of the 15- lipoxygenase enzymatic pathway in the implantation process, stages of pregnancy, embryogenesis, organogenesis, progression of labor, pregnancy period, and pregnancy-associated complications is remarkable. Accordingly, this study will review the research conducted on the role of 15- lipoxygenase in different reproductive tissues, and its pathological role in pregnancy-related diseases to provide more insight regarding the emerging role of 15-lipoxygenase in normal pregnancy.

Longitudinal assessment of leukotriene B4, lipoxin A4, and resolvin D1 plasma levels in pregnant women with risk factors for preeclampsia

OBJECTIVES

We carried out a longitudinal study to compare leukotriene B4 (LTB4), lipoxin A4 (LXA4), and resolvin D1 (RvD1) levels in pregnant women with risk factors for PE - who did (N = 11) or did not develop (N = 17) this clinical condition.

DESIGN & METHODS

For both groups, plasma levels of the lipid mediators were measured using immunoassays at 12-19, 20-29, and 30-34 weeks of gestation.

RESULTS

LTB4 tended to be upregulated throughout gestation in women who developed PE. Moreover, this increase was significant at 30-34 weeks. Although LXA4 levels also tended to be higher in the PE group, this difference was not significant for the evaluated gestational periods. Pregnant women with PE had lower RvD1 levels and a low RvD1/LTB4 ratio at 30-34 weeks, compared to those in the normotensive pregnant women. Contrarily, RvD1 levels increased at weeks 12-19 in pregnant women who developed PE. Particularly, LXA4 and RvD1 levels were higher at 30-34 weeks than those at 20-29 weeks considering both groups of women. We observed an interaction between the gestational outcome and the gestational period in case of RvD1.

CONCLUSIONS

The imbalance among LTB4, LXA4, and RvD1 levels in these preeclamptic women is consistent with the excessive inflammation that underlies the pathogenesis of PE. Although our data highlight the potential for the use of these lipid mediators as clinical markers for PE development, future longitudinal studies must be carried out to confirm these findings.

Changes in erythrocyte membrane epoxyeicosatrienoic, dihydroxyeicosatrienoic, and hydroxyeicosatetraenoic acids during pregnancy

AIMS

Pregnancy is associated with numerous changes in physiological and metabolic processes to ensure successful progression to full term. One such change is the alteration of arachidonic acid (AA) metabolism and formation of eicosanoids. This study explores the changes in AA metabolites formed through the cytochrome P450 mediated pathway to epoxyeicosatrienoic (EET), dihydroxyeicosatrienoic (DHET), and hydroxyeicosatetraenoic (HETE) acids which have been implicated in blood pressure regulation and inflammatory responses that are important for a healthy pregnancy.

MAIN METHODS

The study determines circulating levels of EETs, DHETs and HETEs extracted from erythrocyte membranes and measured by mass spectroscopy during the progression of a normal pregnancy. Blood samples, from 25 women, were collected at three time points including 25-28 weeks gestation, 28-32 weeks gestation, and the non-pregnant control at 3-4 months postpartum.

KEY FINDINGS

Results demonstrate that healthy pregnancy is associated with significant increases in 8,9-DHET, 11,12-DHET and 14,15-DHET and a decrease in trans 8,9-EET during 28-32 weeks gestation compared to 3-4 months postpartum. These differences are likely due to several mechanisms including an increase in soluble epoxide hydrolase activity, a decrease in glutathione conjugation, and altered cytochrome P450 enzyme expression and/or activity that occurs during pregnancy.

SIGNIFICANCE

Metabolism of AA through the cytochrome P450 pathway generates physiologically important eicosanoids that could play an important role in the progression of a healthy pregnancy. Establishing the changes that occur during normal pregnancy may, in the future, help in early detection of pregnancy complications including preeclampsia.

The Role of Arachidonic and Linoleic Acid Derivatives in Pathological Pregnancies and the Human Reproduction Process

The aim of the available literature review was to focus on the role of the proinflammatory mediators of AA and LA derivatives in pathological conditions related to reproduction and pregnancy. Arachidonic (AA) and linoleic acid (LA) derivatives play important roles in human fertility and the course of pathological pregnancies. Recent studies have demonstrated that uncontrolled inflammation has a significant impact on reproduction, spermatogenesis, endometriosis, polycystic ovary syndrome (PCOS) genesis, implantation, pregnancy and labor. In addition, cyclooxygenase-mediated prostaglandins and AA metabolite levels are higher in women’s ovarian tissue when suffering from PCOS. It has been demonstrated that abnormal cyclooxygenase-2 (COX-2) levels are associated with ovulation failure, infertility, and implantation disorders and the increase in 9-HODE/13-HODE was a feature recognized in PCOS patients. Maintaining inflammation without neutrophil participation allows pregnant women to tolerate the fetus, while excessive inflammatory activation may lead to miscarriages and other pathological complications in pregnancies. Additionally AA and LA derivatives play an important role in pregnancy pathologies, e.g., gestational diabetes mellitus, preeclampsia (PE), and fetal growth, among others. The pathogenesis of PE and other pathological states in pregnancy involving eicosanoids have not been fully identified. A significant expression of 15-LOX-1,2 was found in women with PE, leading to an increase in the synthesis of AA and LA derivatives, such as hydroxyeicozatetraenoic acids (HETE) and hydroxyoctadecadiene acids (HODE). Synthesis of the metabolites 5-, 8-, 12-, and 15-HETE increased in the placenta, while 20-HETE increased only in umbilical cord blood in women with preeclampsia compared to normal pregnancies. In obese women with gestational diabetes mellitus (GDM) an increase in epoxygenase products in the cytochrome P450 (CYP) and the level of 20-HETE associated with the occurrence of insulin resistance (IR) were found. In addition, 12- and 20-HETE levels were associated with arterial vasoconstriction and epoxyeicosatrienoic acids (EETs) with arterial vasodilatation and uterine relaxation. Furthermore, higher levels of 5- and 15-HETE were associated with premature labor. By analyzing the influence of free fatty acids (FFA) and their derivatives on male reproduction, it was found that an increase in the AA in semen reduces its amount and the ratio of omega-6 to omega-3 fatty acids showed higher values in infertile men compared to the fertile control group. There are several studies on the role of HETE/HODE in relation to male fertility. 15-Hydroperoxyeicosatetraenoic acid may affect the integrity of the membrane and sperm function. Moreover, the incubation of sperm with physiologically low levels of prostaglandins (PGE2/PGF2α) improves the functionality of human sperm. Undoubtedly, these problems are still insufficiently understood and require further research. However, HETE and HODE could serve as predictive and diagnostic biomarkers for pregnancy pathologies (especially in women with risk factors for overweight and obesity). Such knowledge may be helpful in finding new treatment strategies for infertility and the course of high-risk pregnancies.

Exploring the role of LC-PUFA metabolism in pregnancy complications

Maternal nutrition during pregnancy plays a significant role in growth and development of the placenta and influencing pregnancy outcome. Suboptimal nutritional status during early gestational period compromises the normal course of pregnancy leading to adverse maternal and fetal outcomes. Omega-3 and omega-6 long chain polyunsaturated fatty acids (LC-PUFA) are important for the growth and development of the placenta. Maternal fatty acids and their metabolites influence the normal course of pregnancy by regulating cell growth and development, cell signaling, regulate angiogenesis, modulate inflammatory responses and influence various structural and functional processes. Alterations in LC-PUFA and their metabolites may result in inadequate spiral artery remodeling or placental angiogenesis leading to structural and functional deficiency of the placenta which contributes to several pregnancy complications like preeclampsia, gestational diabetes mellitus, intrauterine growth restriction, and results in adverse birth outcomes. In this review, we summarize studies examining the role of fatty acids and their metabolites in pregnancy. We also discuss the possible molecular mechanisms through which LC-PUFA influences placental growth and development. Studies have demonstrated that omega-3 fatty acid supplementation lowers the incidence of preterm births, but its effect on reducing pregnancy complications are inconclusive.

Serum leukotriene B4 and hydroxyeicosatetraenoic acid in the prediction of pre-eclampsia

INTRODUCTION

Pre-eclampsia (PE) affects 2-8% of pregnancies worldwide. Despite identification of numerous possible biomarkers, accurate prediction and early diagnosis of PE remain challenging. We examined the potential of leukotriene B4 (LTB4) and 15-hydroxyeicosatetraenoic acid (15(S)-HETE) as biomarkers of PE by comparing serum levels at three gestational age (GA) groups between normotensive pregnancies and asymptomatic women who subsequently developed preterm or term-PE.

METHODS

This is a case-control study drawn from a prospective study of adverse pregnancy outcomes with serum samples collected at 19-24 weeks (n = 48), 30-34 weeks (n = 101) and 35-37 weeks (n = 54) GA. LTB4 and 15(S)-HETE levels were determined by ELISA. Serum level multiples of the median (MoM) were compared between normal and PE-pregnancies. Association between LTB4 and 15(S)-HETE and GA at delivery was investigated with Cox proportional-hazards models.

RESULTS

Serum LTB4 levels were lower in women of East-Asian ethnicity, higher in women with PE history, and increased with GA in normotensive pregnancies, but not in PE. LTB4 was elevated at 19-24 weeks in women who developed preterm-PE. There was a negative association between LTB4 MoM and interval between sampling and delivery with PE at 19-24 weeks only. Serum 15(S)-HETE levels were not influenced by GA at testing and were elevated in women of South-Asian ethnicity. Median 15(S)-HETE levels were unchanged in preterm and term-PE at any GA.

DISCUSSION

LTB4 was higher at 19-24 weeks in pregnancies that developed preterm-PE versus unaffected pregnancies, suggesting it is a potentially useful predictive marker of preterm PE in the second trimester.

Inflammation with the participation of arachidonic (AA) and linoleic acid (LA) derivatives (HETEs and HODEs) is necessary in the course of a normal reproductive cycle and pregnancy

Data on arachidonic (AA) and linoleic (LA) acid derivatives and their role in the reproductive cycle are limited. In order to systematize these reports, 54 scientific investigations were analyzed, which revealed the important role of AA and LA in the planning and course of pregnancy. Ovulation, menstruation, pregnancy, and childbirth are strongly related to the occurrence of physiological inflammatory reactions. Ovulation and menstruation are cyclic tissue remodeling processes that cause changes in the synthesis of inflammation mediators, such as prostaglandins and leukotrienes. Thus, the cyclooxygenase (COX) and lipoxygenase-5 (5-LOX) pathway for AA transformation is activated. Only the absence of neutrophils during this process differentiates an embryo implantation from a standard inflammatory response. It has been found that in COX-2 deficiency conditions, incorrect embryo implantation and decidual reaction occur; therefore, the mechanism associated with the activation of the nuclear factor (NF)-κB pathway seems to play an important role in the course of embryo implantation. In addition, 12/15-LOX may be key modulators of uterine activity during the implantation process. According to the current state of knowledge, AA derivatives synthesized throughout the cytochrome P450 (CYP) and LOX pathways play a special role in the late pregnancy period. Decreased 5-HETE levels have been related to slowing down the progression of labor, while 11-HETE and 15-HETrE to its acceleration. It has been also proven that renal 20-HETE contents undergo significant changes in the late pregnancy period, which are caused by an increase in their adrenal medulla and vascular synthesis, leading to decrease of blood pressure and an increase of sodium excretion, finally conditioning a normal course of labor.

Pre-eclampsia is associated with reduced resolvin D1 and maresin 1 to leukotriene B4 ratios in the plasma

PROBLEM

Omega-3 and omega-6 fatty acids can be endogenously converted into mediators with pro-inflammatory (eg, leukotriene B4/LTB4) or anti-inflammatory/pro-resolving activities (eg, resolvin D1/RvD1 and maresin 1/MaR1). Recent data indicate an imbalance of LTB4 and MaR1 levels in pre-eclampsia (PE), but the relative production of these mediators, including RvD1, and the role of these mediators in the disease pathogenesis remain unclear. Therefore, this study aimed to investigate the plasma levels of LTB4, RvD1, and MaR1 in pregnant women with or without PE and non-pregnant controls and their association with clinical/laboratory parameters of PE women.

METHOD OF STUDY

LTB4, RvD1, and MaR1 plasma levels were measured by competitive enzyme immunoassay in 19 non-pregnant, 20 normotensive pregnant, and 21 PE women.

RESULTS

Plasma concentrations of LTB4 were higher and RvD1 were lower in PE women than in normotensive pregnant women, who presented higher levels of LTB4 and similar levels of RvD1 to non-pregnant women. MaR1 levels did not differ among the groups. Pre-eclampsia women had decreased RvD1/LTB4 and MaR1/LTB4 ratios. Considering only the PE group, positive correlations were observed among all the mediators tested, between LTB4 and white blood cell count and between RvD1 and creatinine levels. However, all lipid mediators correlated negatively with body mass index before pregnancy. LTB4 also correlated negatively with maternal age.

CONCLUSION

Our findings suggest that the PE state results in systemic overproduction of LTB4 in relation to RvD1 and MaR1, and that these lipid mediators may be involved with the disease pathogenesis.

Prediction and associations of preterm birth and its subtypes with eicosanoid enzymatic pathways and inflammatory markers

Endogenous signaling molecules derived from lipids, peptides, and DNA, are important regulators of physiological processes during pregnancy. The effect of their collective impact on preterm birth (delivery < 37 weeks gestation) is understudied. We aimed to characterize the associations and predictive capacity of an extensive panel of eicosanoids, immune biomarkers, oxidative stress markers, and growth factors towards preterm birth and its subtypes. We conducted a cross-sectional study of pregnant women (recruited < 15 weeks gestation) in the LIFECODES birth cohort, which included 58 cases of preterm birth and 115 controls that delivered term. Among the cases there were 31 cases who had a spontaneous preterm birth (cases who had spontaneous preterm labor and/or preterm premature rupture of membranes) and 25 that had preterm birth associated with aberrant placentation (cases who had preeclampsia and/or intrauterine growth restriction) and 2 cases that could not be sufficiently categorized as either. We analyzed single biomarker associations with each preterm birth outcome using multiple logistic regression. Adaptive elastic-net was implemented to perform a penalized multiple logistic regression on all biomarkers simultaneously to identify the most predictive biomarkers. We then organized biomarkers into biological groups and by enzymatic pathways and applied adaptive elastic-net and random forest to evaluate the accuracy of each group for predicting preterm birth cases. The majority of associations we observed were for spontaneous preterm birth, and adaptive elastic-net identified 5-oxoeicosatetraenoic acid, resolvin D1, 5,6-epoxy-eicsatrienoic acid, and 15-deoxy-12,14-prostaglandin J2 as most predictive. Overall, lipid biomarkers performed the best at separating cases from controls compared to other biomarker categories (adaptive elastic-net AUC = 0.78 [0.62, 0.94], random forest AUC = 0.84 [0.72, 0.96]). Among the enzymatic pathways that differentiate eicosanoid metabolites, we observed the highest prediction of overall preterm birth by lipoxygenase metabolites using random forest (AUC = 0.83 [0.69, 0.96]), followed by cytochrome p450 metabolites using adaptive elastic-net (AUC = 0.74 [0.52, 0.96]). In this study we translate biological hypothesis into the language of modern machine learning. Many lipid biomarkers were highly associated with overall and spontaneous preterm birth. Among eicosanoids, lipoxygenase and cytochrome p450 products performed best in identifying overall and spontaneous preterm birth. The combination of lipid biomarkers may have good utility in clinical settings to predict preterm birth.

Targeting STOX1 in the therapy of preeclampsia

INTRODUCTION

Preeclampsia is a major pregnancy disease, explained partly by genetic predispositions. STOX1, a transcription factor discovered in 2005, was the first gene directly associated with genetic forms of the disease. Alterations of STOX1 expression as well as STOX1 variants have also been associated to Alzheimer's disease. These observations make of this gene a putative therapeutic target. Area covered: Two major isoforms (STOX1A and STOX1B) are encoded by the gene and are theoretically able to compete for the same binding site, while only the most complete (STOX1A) is supposed to be able to activate gene expression. This makes the ratio between STOX1A and STOX1B as well as their position inside the cell (nucleus or cytoplasm) crucial to understand how STOX1 functions. STOX1 appears to have multiple gene targets, especially in pathways connected to inflammation, oxidative stress, and cell cycle. Expert opinion: STOX1-directed therapies, could be directed either towards its targets (genes or pathways), or directly at STOX1. For this the addressing of STOX1 to various cell compartments could theoretically be modified; also it could be possible of altering the balance between the two isoforms, through selectively inhibiting one of them, possibly improving the outcomes in severe preeclampsia.