Maternal serum dyslipidemia occurs early in pregnancy in women with mild but not severe preeclampsia

Characteristics of Serum Lipid Metabolism among Women Complicated with Hypertensive Disorders in Pregnancy: A Retrospective Cohort Study in Mainland China

Background

Altered maternal serum lipid metabolism is associated with hypertensive disorders in pregnancy (HDP). However, its range in pregnancy and characteristic among different subgroups of HDPs are unclear.

Methods

Pregnant women with HDP who underwent antenatal care and delivered in Obstetrics and Gynecology Hospital of Fudan University during January 2018 to August 2022 were enrolled. The levels of total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDLC), low-density lipoprotein cholesterol (LDLC), apolipoprotein (Apo)-A, B, and E, free fatty acids (FFA), and small and dense low-density lipoprotein cholesterol (sdLDL) were measured during 4-16 weeks and 28-42 weeks of pregnancy.

Results

A total of 2648 pregnant women were diagnosed with HDP, 1,880 of whom were enrolled for final analysis, including 983 (52.3%) preeclampsia (PE), 676 (36.0%) gestational hypertension (GH), and 221 (11.7%) chronic hypertension (CH). For all HDPs, serum TC, TG, LDLC, HDLC, Apo-A, Apo-B, Apo-E, and sdLDL increased significantly during pregnancy, while FFA decreased significantly. Notably, the levels of TC, LDLC, Apo-B, and sdLDL in PE group were equal to or lower than those in CH group at 4-16 weeks of pregnancy, but increased greatly during pregnancy (P < 0.05).

Conclusions

Maternal serum lipid levels changed through pregnancy among women with HDPs. Women complicated with PE seem to have undergone a more significant serum lipid change compared to those with GH or CH.

Postpartum microvascular functional alterations following severe preeclampsia

Preeclampsia is associated with adverse maternal health outcomes later in life. Vascular endothelial dysfunction has been previously described following preeclampsia. We hypothesized that microvascular endothelial dysfunction associated with preeclampsia persists postpartum and may identify those at greatest risk of future cardiovascular disease. The objective of this study was to examine postpartum microvascular endothelial function in women after a pregnancy complicated by preeclampsia. Women with previous preeclampsia (n = 30) and normotensive controls (n = 30) between 6 mo and 5 yr postpartum were recruited. Severity of preeclampsia [severe (n = 16) and mild (n = 14)] was determined by standardized chart review. Microvascular reactivity in the forearm was measured with laser speckle contrast imaging, coupled with iontophoresis; endothelium-dependent and endothelium-independent vasodilation was induced with 1% acetylcholine and sodium nitroprusside solutions, respectively. A postocclusive reactive hyperemia test assessed vasodilatory response following three minutes of suprasystolic (200 mmHg) occlusion with a mechanized cuff. Women with prior severe preeclampsia exhibited significantly higher vasodilation to acetylcholine and sodium nitroprusside compared to controls (P < 0.01; P = 0.03) and prior mild preeclampsia (P = 0.03; P < 0.01). Neither the degree of postocclusive reactive hyperemia (P = 0.98), nor time to return halfway to baseline [OR = 1.026 (0.612, 1.72); P = 0.92], differed between preeclampsia and controls. In conclusion, severe preeclampsia is associated with heightened postpartum microvascular endothelium-dependent and endothelium-independent vasoreactivity. These changes, or a common antecedent, may be linked to postpartum alterations in vascular function that predispose women to disease after preeclampsia. Further investigation should identify the contributing mechanism and the degree to which it could be amenable to medical intervention.NEW & NOTEWORTHY We examine maternal microvascular function after preeclampsia, identifying heightened endothelium-dependent and endothelium-independent microvascular reactivity following severe disease. Our study represents a noteworthy addition to the existing literature with the use of a novel imaging modality, vascular perturbation, postpartum time point, and patient population with differentiation of preeclampsia into severe and nonsevere subtypes. These results represent a novel addition to the growing clinical and academic understanding of maternal health outcomes following preeclampsia.

Maternal lipid profile and risk of pre-eclampsia in African pregnant women: A systematic review and meta-analysis

INTRODUCTION

Some studies have reported the association between maternal serum lipid profile abnormalities and pre-eclampsia. However, many studies have reported controversial results. Hence, this systematic review and meta-analysis was planned to generate summarized evidence on the association between maternal serum lipid profiles and pre-eclampsia in African women.

METHODS

Four electronic databases such as; PubMed, Hinari, Google Scholar, and African Journals Online were searched for studies published in English. Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument and Newcastle-Ottawa Scale were used for data extraction and quality assessment of the included studies. The meta- regression analysis was performed by Stata 14 software. The standardized mean difference (SMD) values of lipid profiles were computed to assess their association with pre-eclampsia at 95% CI.

RESULTS

In this review a total of 15 observational studies were included. The mean values of triglyceride (TG), total cholesterol (TC), low density lipoprotein- cholesterol (LDL-c) and very low density lipoprotein- cholesterol (VLDL-c) were significantly higher in pre-eclamptic women as compared with normotensive pregnant women (TG = 229.61±88.27 and 147.00 ± 40.47, TC = 221.46 ± 45.90 and 189.67 ± 39.18, LDL = 133.92 ± 38.77 and 112.41 ± 36.08, VLDL = 41.44 ± 19.68 and 26.64 ± 7.87), respectively. The serum high density lipoprotein cholesterol (HDL-c) level was lower, but it is not statistically significant (HDL-c = 51.02 ± 16.01 and 61.80 ± 25.63) in pre-eclamptic women as compared with controls. The pooled standardized mean difference (SMD) of TG, TC, LDL-C and VLDL-C were significantly increased in pre-eclamptic women as compared with normotensive pregnant women with the SMD of (TG = 1.65 (1.10, 2.21), TC = 0.84 (0.40, 1.29), LDL-C = 0.95 (0.46, 1.45) and VLDL-C = 1.27 (0.72, 1.81)) at 95% CI, respectively, but the pooled SMD of HDL-cholesterol was decreased in pre-eclamptic women as compared with normotensive pregnant women (SMD = -0.91 (95% CI: -1.43, -0.39).

CONCLUSIONS

In this review, the maternal serum levels of TG, TC, LDL-c and VLDL-c were significantly associated with the risk of preeclampsia. However, HDL- cholesterol was not significantly associated but it was lower in pre-eclamptic women. Further, large scale prospective studies should verify these outcomes and it is recommended that lipid profiles should be included as a routine diagnostic test for pre-eclamptic women.

Non-fasting lipids detection and their significance in pregnant women

BACKGROUND

The majority of pregnant women present an increase in lipids. To investigate the influence of the non-fasting state in the lipid and lipoprotein profile in pregnancy, we have aimed to assess the dynamic change of serum lipid and lipoprotein profile with serum glucose in pregnancy to contrast the differences between fasting and non-fasting state.

METHODS

Forty-five pregnant women and 41 controls were included in our study. All serum samples were assayed for TC, TG, HDL-C, LDL-C, ApoB, ApoA-1, Lp(a), sdLDL, and Glu concentrations. The comparison between pregnant women and controls (fasting and 2 h after breakfast), differences of these measurement results at three point-in-time, the associations between the concentrations of serum lipid and some maternal and fetus characteristics was conducted with statistical analysis.

RESULTS

Except Glu (p < 0.001), there were no significant differences of all lipids between three point-in-time in pregnant women (p > 0.1). The statistically higher levels were found in fasting TC (p = 0.003), TG (p = 0.019), LDL-C (p = 0.002), ApoB (p = 0.001), ApoA1 (p = 0.013) and sdLDL (p < 0.001) of pregnant women compared with controls. Besides, the statistically significances were also found in 2-h TC (p = 0.001), LDL-C (p = 0.001), ApoB (p < 0.001), Glu (p = 0.013), ApoA-1 (p = 0.009) and sdLDL (p < 0.001) of pregnant women compared with controls. Otherwise, in non-fasting status (2 h after breakfast), pregnancy complication was relevant to TC (p = 0.041), HDL-C (p = 0.014), Glu (p = 0.004). Delivery mode was relevant to TC (p = 0.012), HDL-C (p = 0.013), LDL-C (p = 0.026), ApoA-1 (p = 0.012), and sdLDL (p = 0.044). BMI was relevant to TG (p = 0.027).

CONCLUSION

We have suggested the non-fasting lipids detection can be used for estimate lipid metabolism in pregnant women.

Maternal serum lipid in women with preeclampsia in Lagos: a case control study

Objective: This was to determine the serum lipid profile of preeclamptic women and their association with severity of preeclampsia.Methods: This was a case control study conducted at the Lagos University Teaching Hospital, Lagos, Nigeria. Blood samples for serum lipid estimation were collected after an overnight fast. The National Cholesterol Education Program - Adult Treatment Panel (ATP) III criteria were used to define dyslipidemia.Results: Two hundred forty women participated in the study. The mean total cholesterol of preeclamptic and normotensive women was 309.9 ± 10.4 mg/dl and 237 ± 6.8 mg/dl, respectively. Both groups of women had higher than normal mean levels of triglycerides (TG) (203.3 ± 11.0 mg/dl versus 157.5 ± 7.1 mg/dl); low-density lipoprotein (LDL)-c (156.5 ± 11.0 mg/dl versus 109.7 ± 6.9 mg/dl); high-density lipoprotein (HDL)-c (63.2 ± 2.5 mg/dl versus 55.4 ± 1.8 mg/dl) and very low-density lipoprotein (VLDL) (39.5 ± 2.0 mg/dl versus 31.5 ± 1.4 mg/dl). Fewer women with preeclampsia had isolated hypertriglyceridemia (95 versus 99%). Maternal serum total cholesterol (TC), TG, and LDL was significantly (p < .001) higher in severe, compared to mild preeclampsia. Pearson's correlation indicated that all lipids, including total cholesterol (r = 0.406) had positive correlation with preeclampsia.Conclusion: There is elevated serum lipid in pregnancy irrespective of preeclampsia developing. The positive correlation of maternal serum lipids to preeclampsia suggests a casual relationship.

Failure of physiologic transformation of spiral arteries, endothelial and trophoblast cell activation, and acute atherosis in the basal plate of the placenta

BACKGROUND

Failure of physiologic transformation of spiral arteries has been reported in preeclampsia, fetal growth restriction, fetal death, and spontaneous preterm labor with intact or ruptured membranes. Spiral arteries with failure of physiologic transformation are prone to develop atherosclerotic-like lesions of atherosis. There are striking parallels between preeclampsia and atherosclerotic disease, and between lesions of atherosis and atherosclerosis. Endothelial activation, identified by intercellular adhesion molecule-1 expression, is present in atherosclerotic-like lesions of heart transplantation, and is considered a manifestation of rejection. Similarly, endothelial activation/dysfunction has been implicated in the pathophysiology of atherosclerosis and preeclampsia. Intercellular adhesion molecule-1-overexpressing-activated endothelial cells are more resistant to trophoblast displacement than nonactivated endothelium, and may contribute to shallow spiral artery trophoblastic invasion in obstetrical syndromes having failure of physiologic transformation.

OBJECTIVE

We sought to determine whether failure of spiral artery physiologic transformation was associated with activation of interstitial extravillous trophoblasts and/or spiral artery endothelium and presence of acute atherosis in the placental basal plate.

STUDY DESIGN

A cross-sectional study of 123 placentas (19-42 weeks' gestation) obtained from normal pregnancies (n = 22), preterm prelabor rupture of membranes (n = 26), preterm labor (n = 23), preeclampsia (n = 27), intrauterine fetal death (n = 15), and small for gestational age (n = 10) was performed. Failure of spiral artery physiologic transformation and presence of cell activation was determined using immunohistochemistry of placental basal plates containing a median of 4 (minimum: 1; maximum: 9) vessels per placenta. Endothelial/trophoblast cell activation was defined by the expression of intercellular adhesion molecule-1. Investigators examining microscopic sections were blinded to clinical diagnosis. Pairwise comparisons among placenta groups were performed with Fisher exact test and Wilcoxon rank sum test using a Bonferroni-adjusted level of significance (.025).

RESULTS

We found that 87% (94/108) of placentas having spiral arteries with failure of physiologic transformation (actin-positive and cytokeratin-negative) in the basal plate, and 0% (0/15) of placentas having only spiral arteries with complete physiologic transformation (cytokeratin-positive and actin-negative), had arterial endothelial and/or interstitial extravillous trophoblasts reactive with the intercellular adhesion molecule-1 activation marker (P < .001). A significant correlation (R² = 0.84) was found between expression of spiral artery endothelial and interstitial extravillous trophoblast intercellular adhesion molecule-1 (P < .001) in activated placentas. Lesions of atherosis were found in 31.9% (30/94) of placentas with complete and/or partial failure of physiologic transformation of spiral arteries that were intercellular adhesion molecule-1-positive, in none of the 14 placentas with failure of physiologic transformation that were intercellular adhesion molecule-1-negative, and in none of the 15 placentas with complete spiral artery physiologic transformation without failure (P = .001). All placentas (30/30, 100%) with atherosis were identified in placentas having concomitant spiral artery endothelial and interstitial extravillous trophoblast activation.

CONCLUSION

Failure of spiral artery physiologic transformation in the placental basal plate is associated with interstitial extravillous trophoblast and arterial endothelial activation along with increased frequency of spiral artery atherosis. These findings may be used to improve the characterization of different disorders of the placental bed such as in refining the existing tools for the early prediction of risk for preterm, preeclamptic, and other abnormal pregnancies.

Shared biomarkers between female diastolic heart failure and pre-eclampsia: a systematic review and meta-analysis

Evidence accumulates for associations between hypertensive pregnancy disorders and increased cardiovascular risk later. The main goal of this study was to explore shared biomarkers representing common pathogenic pathways between heart failure with preserved ejection fraction (HFpEF) and pre‐eclampsia where these biomarkers might be potentially eligible for cardiovascular risk stratification in women after hypertensive pregnancy disorders. We sought for blood markers in women with diastolic dysfunction in a first literature search, and through a second search, we investigated whether these same biochemical markers were present in pre‐eclampsia.This systematic review and meta‐analysis presents two subsequent systematic searches in PubMed and EMBASE. Search I yielded 3014 studies on biomarkers discriminating women with HFpEF from female controls, of which 13 studies on 11 biochemical markers were included. Cases had HFpEF, and controls had no heart failure. The second search was for studies discriminating women with pre‐eclampsia from women with non‐hypertensive pregnancies with at least one of the biomarkers found in Search I. Search II yielded 1869 studies, of which 51 studies on seven biomarkers were included in meta‐analyses and 79 studies on 12 biomarkers in systematic review.Eleven biological markers differentiated women with diastolic dysfunction from controls, of which the following 10 markers differentiated women with pre‐eclampsia from controls as well: C‐reactive protein, HDL, insulin, fatty acid‐binding protein 4, brain natriuretic peptide, N terminal pro brain natriuretic peptide, adrenomedullin, mid‐region pro adrenomedullin, cardiac troponin I, and cancer antigen 125.Our study supports the hypothesis that HFpEF in women shares a common pathogenic background with pre‐eclampsia. The biomarkers representing inflammatory state, disturbances in myocardial function/structure, and unfavourable lipid metabolism may possibly be eligible for future prognostic tools.

[Relationship between lipid alterations during pregnancy and adverse pregnancy outcomes]

Lipids play an important role during pregnancy, and in this period major changes occur in lipoprotein metabolism. During the third trimester plasma cholesterol and triglyceride levels are substantially increased, returning to normal after delivery. Described associations between increased morbidity during pregnancy and excessive increases in plasma cholesterol and triglycerides. For this reason we have reviewed the relationship between lipid alterations, preeclampsia, gestational diabetes and preterm birth. The overall metabolic control can improve pregnancy outcomes, and the assessment of supraphysiological changes in lipid profile will classify pregnancy risk at a higher level, which would entail a stricter control.

Associations between maternal lipid profile and pregnancy complications and perinatal outcomes: a population-based study from China

Background

Dyslipidemia in pregnancy are associated with gestational diabetes mellitus (GDM), preeclampsia, preterm birth and other adverse outcomes, which has been extensively studied in western countries. However, similar studies have rarely been conducted in Asian countries. Our study was aimed at investigating the associations between maternal dyslipidemia and adverse pregnancy outcomes among Chinese population.

Methods

Data were derived from 934 pairs of non-diabetic mothers and neonates between 2010 and 2011. Serum blood samples were assayed for fasting total cholesterol (TC), triglycerides (TG), high-density lipoprotein-cholesterol (HDL-C), and low-density lipoprotein-cholesterol (LDL-C) concentrations during the first, second and third trimesters. The present study explored the associations between maternal lipid profile and pregnancy complications and perinatal outcomes. The pregnancy complications included GDM, preeclampsia and intrahepatic cholestasis of pregnancy (ICP); the perinatal outcomes included preterm birth, small/large for gestational age (SGA/LGA) infants and macrosomia. Odds ratios (ORs) and 95 % confidence intervals (95 % CIs) were calculated and adjusted via stepwise logistic regression analysis. Optimal cut-off points were determined by ROC curve analysis.

Results

After adjustments for confounders, every unit elevation in third-trimester TG concentration was associated with increased risk for GDM (OR = 1.37, 95 % CI: 1.18-1.58), preeclampsia (OR = 1.50, 95 % CI: 1.16-1.93), ICP (OR = 1.28, 95 % CI: 1.09-1.51), LGA (OR = 1.13, 95 % CI: 1.02-1.26), macrosomia (OR = 1.19, 95 % CI: 1.02-1.39) and decreased risk for SGA (OR = 0.63, 95 % CI: 0.40-0.99); every unit increase in HDL-C concentration was associated with decreased risk for GDM and macrosomia, especially during the second trimester (GDM: OR = 0.10, 95 % CI: 0.03-0.31; macrosomia: OR = 0.25, 95 % CI: 0.09-0.73). The optimal cut-off points for third-trimester TG predicting GDM, preeclampsia, ICP, LGA and SGA were separately ≥3.871, 3.528, 3.177, 3.534 and ≤2.530 mmol/L. The optimal cut-off points for third-trimester HDL-C identifying GDM, macrosomia and SGA were respectively ≤1.712, 1.817 and ≥2.238 mmol/L.

Conclusions

Among Chinese population, maternal high TG in late pregnancy was independently associated with increased risk of GDM, preeclampsia, ICP, LGA, macrosomia and decreased risk of SGA. Relative low maternal HDL-C during pregnancy was significantly associated with increased risk of GDM and macrosomia; whereas relative high HDL-C was a protective factor for both of them.

Prognostic Value of Cardiovascular Disease Risk Factors Measured in the First-Trimester on the Severity of Preeclampsia

Recent studies have suggested that preeclampsia and cardiovascular disease may share common mechanisms. The purpose of this prospective nested case-controlled study was to characterize a variety of cardiovascular disease risk factors measured during the first trimester of pregnancy in predicting subsequent outcomes and the severity of preeclampsia.We ascertained the severity of preeclampsia at the onset of the disease, and the presence of intrauterine growth restriction (IUGR). We compared first trimester maternal serum cardiovascular disease risk factors in preeclampsia subjects versus normal pregnancies, early-onset versus late-onset preeclampsia, and preeclampsia with IUGR versus without IUGR. To identify the prognostic value of independent predictors on the severity of preeclampsia, we calculated the area under the receiver operating characteristics curve (AUC) using logistic regression analysis.There were 134 cases of preeclampsia and 150 uncomplicated pregnancies, and preeclampsia cases were classified as early-onset (53 cases) or late-onset (81 cases), or as with IUGR (44 cases) or without IUGR (90 cases). Among the cardiovascular disease risk factors, maternal serum high-sensitive C-reactive protein (hsCRP) and homocysteine were predictors of both early-onset preeclampsia and preeclampsia with IUGR. For the detection of early onset preeclampsia or preeclampsia with IUGR, the AUC for the combination model (0.943 and 0.952, respectively) was significantly higher than with serum hsCRP or serum homocysteine only.Patients with preeclampsia can be subdivided into different severities according to time of onset and fetal weight. Cardiovascular risk factors distinguish a subgroup of these patients.

Acute Atherosis of the Uterine Spiral Arteries: Clinicopathologic Implications

Acute atherosis is unique vascular changes of the placenta associated with poor placentation. It is characterized by subendothelial lipid-filled foam cells, fibrinoid necrosis of the arterial wall, perivascular lymphocytic infiltration, and it is histologically similar to early-stage atherosclerosis. Acute atherosis is rare in normal pregnancies, but is frequently observed in non- transformed spiral arteries in abnormal pregnancies, such as preeclampsia, small for gestational age (SGA), fetal death, spontaneous preterm labor and preterm premature rupture of membranes. In preeclampsia, spiral arteries fail to develop physiologic transformation and retain thick walls and a narrow lumen. Failure of physiologic transformation of spiral arteries is believed to be the main cause of uteroplacental ischemia, which can lead to the production of anti-angiogenic factors and induce endothelial dysfunction and eventually predispose the pregnancy to preeclampsia. Acute atherosis is more frequently observed in the spiral arteries of the decidua of the placenta (parietalis or basalis) than in the decidual or myometrial segments of the placental bed. The presence and deeper location of acute atherosis is associated with poorer pregnancy outcomes, more severe disease, earlier onset of preeclampsia, and a greater frequency of SGA neonates in patients with preeclampsia. Moreover, the idea that the presence of acute atherosis in the placenta may increase the risk of future cardiovascular disease in women with a history of preeclampsia is of growing concern. Therefore, placental examination is crucial for retrospective investigation of pregnancy complications and outcomes, and accurate placental pathology based on universal diagnostic criteria in patients with abnormal pregnancies is essential for clinicopathologic correlation.

Metabolic syndrome in preeclampsia women in gorgan

The aim of study was to assess the metabolic syndrome in preeclampsia women. The study was performed on 50 women. The metabolic syndrome prevalence was 66%. Serum glucose, triglyceride and LDL-cholesterol levels significantly were increased and HDL- cholesterol level significantly was decreased in metabolic syndrome patients. These patients showed high prevalence of components of the syndrome. Our results show the importance of dyslipidemia in preeclampsia in overweight and obese women. Preeclampsia and cardiovascular disease are important problems for the health of women. It may be useful to give a treat to people with a high-normal blood pressure in early pregnancy.

Lipid profile in nonobese pregnant women with polycystic ovary syndrome: a prospective controlled clinical study

Alterations in lipid pattern and increased risk for obstetric/neonatal complications have been observed in patients with polycystic ovary syndrome (PCOS). Pregnancy leads to physiologic changes in lipoprotein metabolism, and alterations in lipid profile have been related with adverse pregnancy outcomes. Based on these considerations, the aim of the present prospective controlled clinical study was to test the hypothesis that the changes in the lipid profile in patients with PCOS during pregnancy are characteristic and potentially related to the increased risk of obstetric/neonatal complications. One hundred and fifty nonobese PCOS women and 150 age- and body mass index (BMI)-matched healthy controls were enrolled. Serum lipids, glucose, insulin, and androgens levels were serially assayed in all subjects before and throughout pregnancy. Serum low-density lipoprotein (LDL) and triglyceride (TG) concentrations were significantly (P<0.05) higher in PCOS group than in healthy controls at each assessment. Throughout pregnancy, serum LDL and TG levels increased significantly (P<0.05) in both groups, although the change from pre-pregnancy values was significantly (P<0.05) greater in PCOS patients than in healthy controls. A significant (P<0.05) relationship was observed between serum LDL and TG changes and changes in both insulin sensitivity indexes and androgen levels in PCOS patients alone. After adjusting for maternal age, pre-pregnancy BMI and lipid levels, body weight gain, and insulin-resistance markers, serum TG concentrations during pregnancy were directly and independently associated with obstetric complications in both groups, whereas serum LDL levels only in PCOS patients. We can conclude that nonobese PCOS patients had specific changes in lipid profile during pregnancy, and that the lipid pattern typical of PCOS may account for the more frequent adverse pregnancy outcomes. PCOS-related hormonal and metabolic features, such as insulin resistance and high androgen levels, may mediate this phenomenon.

Why does a high-fat diet induce preeclampsia-like symptoms in pregnant rats

Changes in neurotransmitter levels in the brain play an important role in epilepsy-like attacks after pregnancy-induced preeclampsia-eclampsia. Metabotropic glutamate receptor 1 participates in the onset of lipid metabolism disorder-induced preeclampsia. Pregnant rats were fed with a high-fat diet for 20 days. Thus, these pregnant rats experienced preeclampsia-like syndromes such as tension and proteinuria. Simultaneously, metabotropic glutamate receptor 1 mRNA and protein expressions were upregulated in the rat hippocampus. These findings indicate that increased sion of metabotropic glutamate receptor 1 promotes the occurrence of high-fat diet-induced preeclampsia in pregnant rats.

Maternal lipids in pre-eclampsia: innocent bystander or culprit?

Pre-eclampsia continues to be a challenge--to understand the underlying pathogenesis and to prevent or treat in the clinical setting. One area of potential therapies opening up is treatment of maternal lipids and clinical trials are underway using statins in early pre-eclampsia. At present, most potential therapies to treat lipids cannot be recommended for general use in pregnancy and if we were to target maternal lipids to reduce rates of pre-eclampsia, very large numbers of women may need to be treated. Prior to reaching that point, we first need to understand whether maternal lipids are pathogenic in the processes underlying pre-eclampsia. The aim of this review is to examine the role of lipids in the pathogenesis and outcomes of pre-eclampsia, how abnormal lipid genes may be implicated and consider whether treatment of hyperlipidemia has a more general place in the prevention or treatment of pre-eclampsia.

Cardiovascular risk, lipids and pregnancy: preeclampsia and the risk of later life cardiovascular disease

It has been widely thought that the effects of hypertension in pregnancy reversed after delivery and hypertension values returned to their pre-pregnancy level as it was seen as a disease of short duration in otherwise healthy young women. However, recent studies have demonstrated that the principal underlying abnormality, endothelial dysfunction, remains in women who had preeclampsia and that it is this damage that increases the risk of developing cardiovascular disease (CVD) in later life. The contributions of hypertension and dyslipidaemia before and during the pregnancy are also important and contribute to future risk. Serum lipids are complex and change dramatically in pregnancy. In general there is an increase in most plasma lipid components, notably triglycerides, total cholesterol and the major particles of HDL and LDL. Aberrations or exaggerations in this shift (i.e. decrease HDL and a greater increase in LDL) are associated with poor outcomes of pregnancy such as preeclampsia. Long term cardiovascular disease is influenced by preeclampsia and in part potentially by the lipid changes which escalate late in disease. Whether we can influence the risk of preeclampsia by controlling cardiovascular risk factors preceding or during preeclampsia, or cardiovascular disease after preeclampsia is yet to be determined. Ultimately, strategies to control lipid concentrations will only be viable when we understand the safety to the mother at the time of the pregnancy, and to the foetus both immediately and in the very long term. Strategies to control blood pressure are well established in the non-pregnant population, and previous preeclampsia and gestational hypertension should be considered in any cardiovascular risk profile. Whether control of blood pressure in the pregnancy per se is of any longer term benefit is also yet to be determined.

Dimethyl acetals, an indirect marker of the endogenous antioxidant plasmalogen level, are reduced in blood lipids of Sudanese pre-eclamptic subjects whose background diet is high in carbohydrate

In Sudanese women with (n = 60) and without (n = 65) pre-eclampsia, circulating lipids, plasma and red cell saturated and monounsaturated fatty (MUFA) acids and dimethyl acetals (DMAs) were investigated. DMAs are an indirect marker of levels of plasmalogens, endogenous antioxidants, which play a critical role in oxidative protection, and cholesterol homeostasis. The pre-eclamptics had higher C18:1n-9 (p < 0.001) and ΣMUFA (p < 0.01) in plasma free fatty acids, C16:1n-7, C18:1n-9, ΣMUFA; 16:0/16:1n-7 (p < 0.01) in erythrocyte choline phosphoglycerides (ePC) and 16:1n-7, 18:1n-7 and 16:0/16:1n-7 (p < 0.01) in erythrocyte ethanolamine phosphoglycerides (ePE). In contrast, the DMAs 18:0, 18:1 and ΣDMAs in ePE, and 16:0, 18:0 and ΣDMAs in ePC were reduced (p < 0.001) in the pre-eclamptic women. This study of pregnant women with high carbohydrate and low fat background diet suggests pre-eclampsia is associated with oxidative stress and enhanced activity of the microsomal enzyme stearyl-CoA desaturase (delta 9 desaturase), as assessed by palmitic/palmitoleic (C16:0/C16:n-1) and stearic/oleic (C18/C18:1n-9) ratios.

Maternal lipids at mid-pregnancy and the risk of preterm delivery

OBJECTIVE

This study examined associations between maternal lipid levels at mid-pregnancy and preterm delivery, medically indicated or spontaneous.

DESIGN

Prospective cohort study.

SETTING

Women were recruited from 52 clinics in five Michigan, USA communities (1998-2004).

POPULATION

Pregnant women were enrolled at 15-27 weeks' gestation and followed to delivery (n=3019).

METHODS

A single blood sample was obtained at study enrollment. Blood lipids, i.e. total cholesterol (TC), high-density lipoprotein (HDLc), low-density lipoprotein (LDLc) cholesterol, and triglycerides (TG), were measured on a sub-cohort (n=1309).

MAIN OUTCOME MEASURES

There were 221 spontaneous, 100 medically indicated preterm deliveries and 988 term deliveries. Polytomous logistic regression models examined relationships among cholesterol levels (Low: <10(th) percentile, Referent: 10(th) -<70(th) percentile, High: ≥70(th) percentile), quartiles of TG (Referent: first quartile) and delivery outcome (Referent: term).

RESULTS

Odds of medically indicated preterm delivery were increased among women with low TC (adjusted odds ratio (aOR)=2.04, 95% confidence interval (CI): 1.12, 3.72), low HDLc (aOR=1.89, 95%CI: 1.04, 3.42) or low LDLc (aOR=1.96, 95%CI: 1.09, 3.54). Odds of spontaneous preterm delivery were increased among women with high TC (aOR=1.51, 95%CI: 1.06, 2.15), high LDLc (aOR=1.42, 95%CI: 0.99, 2.04) or high TG (aOR=1.90, 95%CI: 1.21, 2.97 and aOR=1.72, 95%CI: 1.06, 2.78 for third and fourth quartiles, respectively).

CONCLUSIONS

Extremely low TC, HDLc, and LDLc were associated with a modest increase in risk of medically indicated preterm delivery, whereas high TC, LDLc and TG modestly increased the risk of spontaneous preterm delivery. Further research is needed to uncover explanations for these associations and to identify optimal ranges for maternal lipids.

Triglyceride metabolism in pregnancy

During pregnancy, complex changes occur in lipid profiles. From the 12th week of gestation, phospholipids, cholesterol (total, LDL, HDL), and triglycerides (TG) increase in response to estrogen stimulation and insulin resistance. Transition to a catabolic state favors maternal tissue lipid use as energy sources, thus sparing glucose and amino acids for the fetus. In addition, maternal lipids, that is, cholesterol, are available for fetal use in building cell membranes and as precursor of bile acids and steroid hormones. It is also required for cell proliferation and development of the growing body. Free-fatty acids (FFA), oxidized in the maternal liver as ketone-bodies, represent an alternative fuel for the fetus. Maternal hypertriglyceridemia (vs. other lipids) has many positive effects such as contributing to fetal growth and development and serving as an energy depot for maternal dietary fatty acids. However, increased TG during pregnancy appears to increase risk of preeclampsia and preterm birth. Some have suggested that maternal hypertriglyceridemia has a role in increasing cardiovascular risk later in life. This chapter reviews lipid metabolism during pregnancy to elucidate its effect on fetal growth and its potential role in pregnancy-associated complications and future cardiovascular risk.

Expression of aryl hydrocarbon receptor in human placentas and fetal tissues

The aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, mediates many biological processes, including fetal development. In this study, we examined AhR protein expression in human placentas from normal (N) and severe preeclamptic (sPE) pregnancies, as well as human fetal tissues from the second trimester of pregnancy, using immunohistochemistry and/or Western blot analysis. In the placentas, the AhR immunoreactivity was present primarily in syncytiotrophoblasts. The AhR staining was also seen in endothelium of large blood vessels in villi and endothelium of umbilical cord arteries and veins. No difference in AhR protein levels was found between N and sPE placentas. In fetal tissues, the AhR immunoreactivity was localized in lung, kidney, esophagus, pancreas, liver, testicle, thymus gland, retina, and choroid, mainly in epithelial cells, whereas it was absent in heart, brain, sclera, and thoracic aorta. These findings suggest that the AhR plays a critical role in syncytiotrophoblasts of human placentas and epithelium of many fetal organs. These data also imply that human placentas and those fetal organs with high AhR expression (e.g., lung, kidney, liver, pancreas, and thymus gland) during fetal development are highly susceptible to environmental toxicants such as dioxin.