Alterations in Antioxidant Micronutrient Concentrations in Placental Tissue, Maternal Blood and Urine and the Fetal Circulation in Pre-eclampsia.

Trace elements such as selenium and zinc are vital components of many enzymes, including endogenous antioxidants, and can interact with each other. Women with pre-eclampsia, the hypertensive disease of pregnancy, have been reported as having changes in some individual antioxidant trace elements during pregnancy, which are related to maternal and fetal mortality and morbidity. We hypothesised that examination of the three compartments of (a) maternal plasma and urine, (b) placental tissue and (c) fetal plasma in normotensive and hypertensive pregnant women would allow identification of biologically significant changes and interactions in selenium, zinc, manganese and copper. Furthermore, these would be related to changes in the angiogenic markers, placental growth factor (PlGF) and Soluble Fms-Like Tyrosine Kinase-1 (sFlt-1) concentrations. Venous plasma and urine were collected from healthy non-pregnant women (n = 30), normotensive pregnant controls (n = 60) and women with pre-eclampsia (n = 50) in the third trimester. Where possible, matched placental tissue samples and umbilical venous (fetal) plasma were also collected. Antioxidant micronutrient concentrations were measured by inductively coupled plasma mass-spectrometry. Urinary levels were normalised to creatinine concentration. Plasma active PlGF and sFlt-1 concentrations were measured by ELISA. Maternal plasma selenium, zinc and manganese were all lower in women with pre-eclampsia (p < 0.05), as were fetal plasma selenium and manganese (p < 0.05 for all); maternal urinary concentrations were lower for selenium and zinc (p < 0.05). Conversely, maternal and fetal plasma and urinary copper concentrations were higher in women with pre-eclampsia (p < 0.05). Differences in placental concentrations varied, with lower overall levels of selenium and zinc (p < 0.05) in women with pre-eclampsia. Maternal and fetal PlGF were lower and sFlt-1 higher in women with pre-eclampsia; maternal plasma zinc was positively correlated with maternal plasma sFlt-1 (p < 0.05). Because of perceptions that early- and late-onset pre-eclampsia have differing aetiologies, we subdivided maternal and fetal data accordingly. No major differences were observed, but fetal sample sizes were small following early-onset. Disruption in these antioxidant micronutrients may be responsible for some of the manifestations of pre-eclampsia, including contributing to an antiangiogenic state. The potential benefits of mineral supplementation, in women with deficient intakes, during pregnancy to reduce pre-eclampsia remain an important area for experimental and clinical research.

Fetal cardiac dysfunction in intrahepatic cholestasis of pregnancy is associated with elevated serum bile acid concentrations.

BACKGROUND & AIMS: Intrahepatic cholestasis of pregnancy (ICP) is associated with an increased risk of stillbirth. This study aimed to assess the relationship between bile acid concentrations and fetal cardiac dysfunction in patients with ICP who were or were not treated with ursodeoxycholic acid (UDCA). METHODS: Bile acid profiles and NT-proBNP, a marker of ventricular dysfunction, were assayed in umbilical venous serum from 15 controls and 76 ICP cases (36 untreated, 40 UDCA-treated). Fetal electrocardiogram traces were obtained from 43 controls and 48 ICP cases (26 untreated, 22 UDCA-treated). PR interval length and heart rate variability (HRV) parameters were measured in 2 behavioral states (quiet and active sleep). RESULTS: In untreated ICP, fetal total serum bile acid (TSBA) concentrations (r = 0.49, p = 0.019), hydrophobicity index (r = 0.20, p = 0.039), glycocholate concentrations (r = 0.56, p = 0.007) and taurocholate concentrations (r = 0.44, p = 0.039) positively correlated with fetal NT-proBNP. Maternal TSBA (r = 0.40, p = 0.026) and alanine aminotransferase (r = 0.40, p = 0.046) also positively correlated with fetal NT-proBNP. There were no significant correlations between maternal or fetal serum bile acid concentrations and fetal HRV parameters or NT-proBNP concentrations in the UDCA-treated cohort. Fetal PR interval length positively correlated with maternal TSBA in untreated (r = 0.46, p = 0.027) and UDCA-treated ICP (r = 0.54, p = 0.026). Measures of HRV in active sleep and quiet sleep were significantly higher in untreated ICP cases than controls. HRV values in UDCA-treated cases did not differ from controls. CONCLUSIONS: Elevated fetal and maternal serum bile acid concentrations in untreated ICP are associated with an abnormal fetal cardiac phenotype characterized by increased NT-proBNP concentration, PR interval length and HRV. UDCA treatment partially attenuates this phenotype. LAY SUMMARY: The risk of stillbirth in intrahepatic cholestasis of pregnancy (ICP) is linked to the level of bile acids in the mother which are thought to disrupt the baby's heart rhythm. We found that babies of women with untreated ICP have abnormally functioning hearts compared to those without ICP, and the degree of abnormality is closely linked to the level of harmful bile acids in the mother and baby's blood. Babies of women with ICP who received treatment with the drug UDCA do not have the same level of abnormality in their hearts, suggesting that UDCA could be a beneficial treatment in some ICP cases, although further clinical trials are needed to confirm this.

Increased Placental Cell Senescence and Oxidative Stress in Women with Pre-Eclampsia and Normotensive Post-Term Pregnancies.

Up to 11% of pregnancies extend to post-term with adverse obstetric events linked to pregnancies over 42 weeks. Oxidative stress and senescence (cells stop growing and dividing by irreversibly arresting their cell cycle and gradually ageing) can result in diminished cell function. There are no detailed studies of placental cell senescence markers across a range of gestational ages, although increased levels have been linked to pre-eclampsia before full term. This study aimed to determine placental senescence and oxidative markers across a range of gestational ages in women with uncomplicated pregnancies and those with a diagnosis of pre-eclampsia. Placentae were obtained from 37 women with uncomplicated pregnancies of 37-42 weeks and from 13 cases of pre-eclampsia of 31+2-41+2 weeks. The expression of markers of senescence, oxidative stress, and antioxidant defence (tumour suppressor protein p16INK4a, kinase inhibitor p21, interleukin-6 (IL-6), NADPH oxidase 4 (NOX4), glutathione peroxidases 1, 3, and 4 (GPx1, GPx3, and GPx4), placental growth factor (PlGF), and soluble fms-like tyrosine kinase-1 (sFlt-1)) genes was measured (quantitative real-time PCR). Protein abundance of p16INK4a, IL-6, NOX4, 8-hydroxy-2'-deoxy-guanosine (8-OHdG), and PlGF was assessed by immunocytochemistry. Placental NOX4 protein was higher in post-term than term deliveries and further increased by pre-eclampsia (p < 0.05 for all). P21 expression was higher in post-term placentae (p = 0.012) and in pre-eclampsia (p = 0.04), compared to term. Placental P16INK4a protein expression was increased post-term, compared to term (p = 0.01). In normotensive women, gestational age at delivery was negatively associated with GPx4 and PlGF (mRNA and protein) (p < 0.05 for all), whereas a positive correlation was seen with placental P21, NOX4, and P16INK4a (p < 0.05 for all) expression. Markers of placental oxidative stress and senescence appear to increase as gestational age increases, with antioxidant defences diminishing concomitantly. These observations increase our understanding of placental health and may contribute to assessment of the optimal gestational age for delivery.

Increased maternal and fetal cholesterol efflux capacity and placental CYP27A1 expression in preeclampsia.

Preeclampsia is a pregnancy-specific condition that leads to increased cardiovascular risk in later life. A decrease in cholesterol efflux capacity is linked to CVD. We hypothesized that in preeclampsia there would be a disruption of maternal/fetal plasma to efflux cholesterol, as well as differences in the concentrations of both placental sterol 27-hydroxylase (CYP27A1) and apoA1 binding protein (AIBP). Total, HDL-, and ABCA1-mediated cholesterol effluxes were performed with maternal and fetal plasma from women with preeclampsia and normotensive controls (both n = 17). apoA1 and apoE were quantified by chemiluminescence, and 27-hydroxycholesterol (27-OHC) by GC-MS. Immunohistochemistry was used to determine placental expression/localization of CYP27A1, AIBP, apoA1, apoE, and SRB1. Maternal and fetal total and HDL-mediated cholesterol efflux capacities were increased in preeclampsia (by 10-20%), but ABCA1-mediated efflux was decreased (by 20-35%; P < 0.05). Maternal and fetal apoE concentrations were higher in preeclampsia. Fetal plasma 27-OHC levels were decreased in preeclamptic samples (P < 0.05). Placental protein expression of both CYP27A1 and AIBP were localized around fetal vessels and significantly increased in preeclampsia (P = 0.04). Placental 27-OHC concentrations were also raised in preeclampsia (P < 0.05). Increased HDL-mediated cholesterol efflux capacity and placental CYP27A1/27-OHC could be a rescue mechanism in preeclampsia, to remove cholesterol from cells to limit lipid peroxidation and increase placental angiogenesis.

Human placental renin-angiotensin system in normotensive and pre-eclamptic pregnancies at high altitude and after acute hypoxia-reoxygenation insult.

A functioning placental renin-angiotensin system (RAS) appears necessary for uncomplicated pregnancy and is present during placentation, which occurs under low oxygen tensions. Placental RAS is increased in pre-eclampsia (PE), characterised by placental dysfunction and elevated oxidative stress. We investigated the effect of high altitude hypoxia on the RAS and hypoxia-inducible factors (HIFs) by measuring mRNA and protein expression in term placentae from normotensive (NT) and PE women who delivered at sea level or above 3100 m, using an explant model of hypoxia-reoxygenation to assess the impact of acute oxidative stress on the RAS and HIFs. Protein levels of prorenin (P = 0.049), prorenin receptor (PRR; P = 0.0004), and angiotensin type 1 receptor (AT1R, P = 0.006) and type 2 receptor (AT2R, P = 0.002) were all significantly higher in placentae from NT women at altitude, despite mRNA expression being unaffected. However, mRNA expression of all RAS components was significantly lower in PE at altitude than at sea level, yet PRR, angiotensinogen (AGT) and AT1R proteins were all increased. The increase in transcript and protein expression of all the HIFs and NADPH oxidase 4 seen in PE compared to NT at sea level was blunted at high altitude. Experimentally induced oxidative stress stimulated AGT mRNA (P = 0.04) and protein (P = 0.025). AT1R (r = 0.77, P < 0.001) and AT2R (r = 0.81, P < 0.001) mRNA both significantly correlated with HIF-1ß, whilst AT2R also correlated with HIF-1α (r = 0.512, P < 0.013). Our observations suggest that the placental RAS is responsive to changes in tissue oxygenation: this could be important in the interplay between reactive oxygen species as cell-signalling molecules for angiogenesis and hence placental development and function.

Maternal selenium, copper and zinc concentrations in pregnancy associated with small-for-gestational-age infants.

Pregnancy during adolescence increases the risk of adverse pregnancy outcome, especially small-for-gestational-age (SGA) birth, which has been linked to micronutrient deficiencies. Smoking has been shown to be related to lower micronutrient concentrations. Different ethnicities have not been examined. We used a subset from a prospective observational study, the About Teenage Eating study consisting of 126 pregnant adolescents (14-18-year-olds) between 28 and 32 weeks gestation. Micronutrient status was assessed by inductively coupled mass spectrometry. Smoking was assessed by self-report and plasma cotinine, and SGA was defined as infants born <10th corrected birthweight centile. The main outcome measures were as follows: (1) maternal plasma selenium, copper and zinc concentrations in adolescent mothers giving birth to SGA vs. appropriate-for-gestational-age (AGA) infants; and (2) comparison of micronutrient concentrations between women of different ethnicities and smoking habits. The plasma selenium {mean ± standard deviation (SD) [95% confidence interval (CI)]} concentration was lower in the SGA [n = 19: 49.4 ± 7.3 (CI: 45.9, 52.9) µg L(-1)] compared with the AGA [n = 107: 65.1 ± 12.5 (CI: 62.7, 67.5) µg L(-1); P < 0.0001] group. Smoking mothers had a lower selenium concentration compared with non-smokers (P = 0.01) and Afro-Caribbean women had higher selenium concentrations compared with White Europeans (P = 0.02). Neither copper nor zinc concentrations varied between groups. Low plasma selenium concentration in adolescent mothers could contribute to the risk of delivering an SGA infant, possibly through lowering placental antioxidant defence, thus directly affecting fetal growth. Differences in plasma selenium between ethnicities may relate to variation in nutritional intake, requiring further investigation.

Alterations of Placental Sodium in Preeclampsia: Trophoblast Responses.

BACKGROUND: Evidence suggests that increasing salt intake in pregnancy lowers blood pressure, protecting against preeclampsia. We hypothesized that sodium (Na+) evokes beneficial placental signals that are disrupted in preeclampsia. METHODS: Blood and urine were collected from nonpregnant women of reproductive age (n=26) and pregnant women with (n=50) and without (n=55) preeclampsia, along with placental biopsies. Human trophoblast cell lines and primary human trophoblasts were cultured with varying Na+ concentrations. RESULTS: Women with preeclampsia had reduced placental and urinary Na+ concentrations, yet increased urinary angiotensinogen and reduced active renin, aldosterone concentrations, and osmotic response signal TonEBP (tonicity-responsive enhancer binding protein) expression. In trophoblast cell cultures, TonEBP was consistently increased upon augmented Na+ exposure. Mechanistically, inhibiting Na+/K+-ATPase or adding mannitol evoked the TonEBP response, whereas inhibition of cytoskeletal signaling abolished it. CONCLUSIONS: Enhanced Na+ availability induced osmotic gradient-dependent cytoskeletal signals in trophoblasts, resulting in proangiogenic responses. As placental salt availability is compromised in preeclampsia, adverse systemic responses are thus conceivable.

Is the atherosclerotic phenotype of preeclamptic placentas due to altered lipoprotein concentrations and placental lipoprotein receptors? Role of a small-for-gestational-age phenotype.

Atherosis of spiral arteries in uteroplacental beds from preeclamptic women resemble those of atherosclerosis, characterized by increased plasma lipids and lipoproteins. We hypothesized that: 1) lipoprotein receptors/transporters in the placenta would be upregulated in preeclampsia, associated with increased maternal and fetal lipoprotein concentrations; and 2) expression of these would be reduced in preeclamptic placentae from women delivering small-for-gestational-age (SGA) infants. Placental biopsies and maternal and umbilical serum samples were taken from 27 normotensive and 24 preeclamptic women. Maternal/umbilical cord serum LDL, HDL, total cholesterol, and triglycerides were measured. Placental mRNA expression of lipoprotein receptors/transporters were quantified using quantitative RT-PCR. Protein localization/expression of LDL receptor-related protein 1 (LRP-1) in the preeclamptic placentae with/without SGA was measured by immunohistochemistry. Placental mRNA expression of all genes except paraoxonase-1 (PON-1), microsomal triglyceride transfer protein (MTTP), and protein disulfide isomerase family A member 2 (PDIA2) were observed. No differences for any lipoprotein receptors/transporters were found between groups; however, in the preeclamptic group placental LRP-1 expression was lower in SGA delivering mothers (n = 7; P = 0.036). LRP-1 protein was localized around fetal vessels and Hofbauer cells. This is the first detailed study of maternal/fetal lipoprotein concentrations and placental lipoprotein receptor mRNA expression in normotensive and preeclamptic pregnancies. These findings do not support a role of altered lipid metabolism in preeclampsia, but may be involved in fetal growth.

The differential placental expression of ERp44 and pre-eclampsia; association with placental zinc, the ERAP1 and the renin-angiotensin-system.

INTRODUCTION: Endoplasmic reticulum resident protein 44 (ERp44) is a zinc-metalloprotein, regulating Endoplasmic reticulum aminopeptidase 1 (ERAP1) and Angiotensin II (Ang II). We explored placental ERp44 expression and components of the renin-angiotensin-system (RAS) in pre-eclampsia (PE), correlating these to ERAP1 expression and placental zinc concentrations. METHODS: Placental tissue, taken at time of delivery in normotensive women or women with PE (n = 12/group), were analysed for ERp44, AT1R, AT2R and AT4R by qPCR. Protein ERp44 expression was measured by immunohistochemistry and compared to previously measured ERAP1 expression. Placental zinc was measured by inductively-coupled-mass-spectrometry. RESULTS: ERp44 gene/protein expression were increased in PE (P < 0.05). AT1R expression was increased (P = 0.02) but AT4R decreased (P = 0.01) in PE, compared to normotensive controls. A positive association between ERp44 and AT2R expression was observed in all groups. ERp44 was negatively correlated with ERAP1 protein expression in all samples. Placental zinc concentrations were lower in women with PE (P = 0.001) and negatively associated with ERp44 gene expression. DISCUSSION: Increased placental ERp44 could further reduce ERAP1 release in PE, potentially preventing release of Ang IV and thus lowering levels of Ang IV which consequently diminishes the possibility of counterbalancing the activity of vasoconstrictive, Ang II. The lower placental zinc may contribute to dysfunction of the ERp44/ERAP1 complex, exacerbating the hypertension in PE.

Reduced Brain Cortex Angiogenesis in the Offspring of the Preeclampsia-Like Syndrome.

BACKGROUND: Children from pregnancies affected by preeclampsia have an increased risk of cognitive and behavioral alterations via unknown pathophysiology. We tested the hypothesis that preeclampsia generated reduced brain cortex angiogenesis in the offspring. METHODS: The preeclampsia-like syndrome (PELS) mouse model was generated by administering the nitric oxide inhibitor NG-nitroarginine methyl ester hydrochloride. Confirmatory experiments were done using 2 additional PELS models. While in vitro analysis used mice and human brain endothelial cells exposed to serum of postnatal day 5 pups or umbilical plasma from preeclamptic pregnancies, respectively. RESULTS: We report significant reduction in the area occupied by blood vessels in the motor and somatosensory brain cortex of offspring (postnatal day 5) from PELS compared with uncomplicated control offspring. These data were confirmed using 2 additional PELS models. Furthermore, circulating levels of critical proangiogenic factors, VEGF (vascular endothelial growth factor), and PlGF (placental growth factor) were lower in postnatal day 5 PELS. Also we found lower VEGF receptor 2 (KDR [kinase insert domain-containing receptor]) levels in mice and human endothelial cells exposed to the serum of postnatal day 5 PELS or fetal plasma of preeclamptic pregnancies, respectively. These changes were associated with lower in vitro angiogenic capacity, diminished cell migration, larger F-actin filaments, lower number of filopodia, and lower protein levels of F-actin polymerization regulators in brain endothelial cells exposed to serum or fetal plasma of offspring from preeclampsia. CONCLUSIONS: Offspring from preeclampsia exhibited diminished brain cortex angiogenesis, associated with lower circulating VEGF/PlGF/KDR protein levels, impaired brain endothelial migration, and dysfunctional assembly of F-actin filaments. These alterations may predispose to structural and functional alterations in long-term brain development.

Effects of aldosterone on the human placenta: Insights from placental perfusion studies.

INTRODUCTION: In pregnancy, aldosterone is linked to maternal plasma volume expansion, improved fetal and placental growth/angiogenesis and reduced maternal blood pressure. Aldosterone levels are low in women with pre-eclampsia. Given the placental growth properties of aldosterone in pregnancy, we hypothesised that increased aldosterone improves placental function ex vivo. We applied aldosterone in the dual human placenta perfusion model and analysed specific regulatory markers. METHODS: A single cotyledon was perfused using a trimodal perfusion setup consisting of a control phase (CP; basic perfusion medium (BPM) alone) and two consecutive experimental phases (EP1/EP2; BPM supplemented with 1.5 x 10-9M and 1.5 x 10-7M aldosterone, respectively). CP and EP1/EP2 were conducted in closed circuits lasting 2 h each. Quality/time control perfusions using BPM alone were performed for 360 min to distinguish time-dependent effects from aldosterone-related effects. Perfusates were assessed for control parameters (pH/pO2/pCO2/glucose/lactate/creatinine/antipyrine). Maternal perfusates were analysed for placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1), interleukin-10 (IL-10) and tumour necrosis factor-alpha (TNF-α) using ELISAs. mRNA expression of abovementioned factors was measured by qPCR in post-perfusion tissue. RESULTS: Data from quality/time control perfusions indicated that TNF-α and IL-10 release continuously increased over time. Contrary, in the trimodal perfusion setup the application of aldosterone decreased TNF-α secretion (P < 0.05, EP1/EP2 vs CP, 120 min) and increased PlGF release (P < 0.05, EP1 vs CP, 90/120 min) into the maternal perfusates. mRNA expression followed similar trends, but did not reach significance. DISCUSSION: Our ex vivo placental perfusion data suggest that increasing aldosterone promotes anti-inflammatory and pro-angiogenic factors, which could positively contribute to healthy pregnancy outcomes.

Maternal, Fetal, and Placental Selectins in Women With Pre-eclampsia; Association With the Renin-Angiotensin-System.

Selectins [endothelial (E), platelet (P), and leucocytes (L)] are a class of cell adhesion molecules, stimulated in response to inflammation. Pre-eclampsia is characterized by inflammation, and angiotensin II is pro-inflammatory. We hypothesized that circulating maternal and fetal concentrations and placental expression of selectins would be increased in women with pre-eclampsia and would be associated with the angiotensin receptors (AT1R and AT2R). Maternal and fetal blood and placental tissue was collected at delivery from White European normotensive controls (n = 17) and women with pre-eclampsia (n = 17). Soluble (s) E-, P- and L-selectin protein concentrations were measured by ELISA and placental protein expression was examined by immunohistochemistry. Maternal sE-selectin concentrations were increased in pre-eclampsia (P < 0.001); conversely fetal sE- and sP-selectin levels were lower in pre-eclampsia (P < 0.05 for both). Staining was mainly localized to the syncytiotrophoblast for all selectins. E-selectin expression was increased, while P-selectin was decreased in placental from pre-eclampsia (P < 0.05 for both); no differences were observed for L-selectin expression. Both E- and L-selectin were positively correlated (P < 0.008; P < 0.02) with AT2R placental expression, whilst P-selectin was negatively associated with AT1R (P < 0.005), all only in the pre-eclampsia group. This novel study reports maternal, fetal and placental expression of selectins in pre-eclampsia. The increased E-selectins reflect the endothelial dysfunction, characteristic of pre-eclampsia. In contrast, the reduced P-selectins and the positive association of placental AT2Rs with both E-and L-selectin in pre-eclampsia could be a protective mechanism to limit the endothelial dysfunction.

The Differential Expression of ERAP1/ERAP2 and Immune Cell Activation in Pre-eclampsia.

Pre-eclampsia (PE) is a disorder of pregnancy, often leading to serious and fatal complications. Endoplasmic reticulum aminopeptidase 1 and 2 (ERAP1/ERAP2) are present in the placenta. They are involved in processes regulating blood pressure, angiogenesis, cytokine receptor shedding, and immune recognition. Previous studies have associated both ERAP1/ERAP2 genetic variants with PE, although the underlying mechanisms remain unknown. Less is known about the roles for these enzymes in early placentation, which could be a contributory factor to PE. To ascertain whether ERAP1/ERAP2 change in PE and whether such a change is present before PE is clinically diagnosed, we analyzed mRNA and ERAP1/2 protein expression in the placenta in the early first trimester (8-14 weeks) and at delivery in normotensive or PE women (n = 12/group). Gene expression was analyzed using qPCR, and protein expression and localization were assessed by immunohistochemistry. Additionally, we profiled peripheral immune cells from normotensive and PE (n = 5/group) women for activation and expression of cytotoxic markers using flow cytometry to investigate a possible correlation with placental expression of ERAP1/2. Finally, we characterized the cytokines released from immune cells isolated from normotensive women and those with PE, stimulated ex vivo by JEG-3 trophoblast cells. The ERAP1 protein was significantly upregulated in first trimester placentae compared to placentae at delivery from both normotensive and PE women (p < 0.05): expression of placental ERAP1 protein was also relatively higher in normotensive than PE women. Although the protein expression of both ERAP1/ERAP2 was significantly lower in women with PE compared to normotensive controls (p < 0.05), ERAP2 protein expression remained unchanged in normotensive women at delivery compared to expression in the first trimester. Flow cytometry analysis revealed an increase in activation and cytotoxic natural killer (NK) cells in peripheral blood of PE compared to normotensive women. Intriguingly, there was a notable difference in cytokine release from the activated immune cells when further stimulated by trophoblast cells. The immune cells from PE released elevated expressions of interleukin (IL)-2, IL-4, and most notably, pro-inflammatory IL-13 and IL-17α, inflammatory cytokines tumor necrosis factor (TNF)-α and interferon (IFN)-γ, and granulocyte-macrophage colony-stimulating factor (GM-CSF) compared to normal peripheral blood mononuclear cells (PBMCs). Taken together, these findings suggest that differential lymphocyte activation could be associated with altered ERAP1/ERAP2 expression.

A pilot study of alterations in oxidized angiotensinogen and antioxidants in pre-eclamptic pregnancy.

The oxidation status of angiotensinogen (AGT) may have a critical role in pre-eclampsia. We used a validated, quantitative, mass spectrometry-based method to measure the oxidized and total AGT levels in plasma of pre-eclamptic women (n = 17), normotensive-matched controls (n = 17), and healthy non-pregnant women (n = 10). Measurements of plasma glutathione peroxidase (GPx) activity and serum selenium concentrations were performed as markers of circulating antioxidant capacity. Higher proportions of oxidized AGT in plasma from pre-eclamptic women compared to matched normotensive pregnant controls (P = 0.006), whilst maintaining a similar total plasma AGT concentration were found. In the pre-eclamptic group, blood pressure were correlated with the proportion of oxidized AGT; no such correlation was seen in the normotensive pregnant women. Plasma GPx was inversely correlated with oxidized AGT, and there was an inverse association between serum selenium concentration and the proportion of oxidized AGT. This is the first time that oxidized AGT in human plasma has been linked directly to antioxidant status, providing a mechanism for the enhanced oxidative stress in pre-eclampsia. We now provide pathophysiological evidence that the conversion of the reduced form of AGT to its more active oxidized form is associated with inadequate antioxidant status and could indeed contribute to the hypertension of pre-eclampsia.

Responses of the renin-angiotensin-aldosterone system in pregnant chronic kidney disease patients with and without superimposed pre-eclampsia.

BACKGROUND: Women with chronic kidney disease (CKD) are at increased risk of superimposed pre-eclampsia (SPE). Accurate identification of SPE is challenging. We hypothesized that specific components of the renin-angiotensin-aldosterone system (RAAS) would discriminate between CKD and SPE. The aim of the study was to establish differences in circulating and intrarenal RAAS in women with CKD with and without SPE and compare these to normotensive controls (NCs) and women with pre-eclampsia (PE). METHODS: White European NC women (n = 20), women with PE (n = 9), normotensive CKD without SPE (n = 8) and with SPE (n = 11) were recruited in the third trimester. Plasma renin, plasma and urine total angiotensinogen (AGT) concentrations were quantified by enzyme-linked immunosorbent assay, urinary tetrahydroaldosterone (TH-aldo) concentration by gas chromatography-mass spectrometry and placental growth factor (PlGF) by immunoassay. RESULTS: Urinary TH-aldo:creatinine ratios were lower in women with PE or SPE compared with NC or women with CKD (P < 0.05 for all). The same group differences were observed for plasma active renin and PlGF concentrations (P < 0.05 for all). Urine total AGT was higher in women with PE compared with NC (P < 0.05) and urine TH-aldo:urine AGT was lower (P < 0.05). However, women with SPE had lower urinary AGT concentrations compared with women with PE (P < 0.05). No differences in plasma total AGT were observed between groups. CONCLUSIONS: Women with SPE have a lower urinary TH-aldo:creatinine ratio, lower plasma active renin and lower PlGF concentrations than women with CKD, comparable to women with PE without pre-existing disease, suggestive of similar pathophysiology. These data suggest disruption of the RAAS pathway in SPE similar to PE. Exploration of the predictive value of RAAS components for adverse pregnancy events in women with CKD is required.

Evidence of Augmented Intrarenal Angiotensinogen Associated With Glomerular Swelling in Gestational Hypertension and Preeclampsia: Clinical Implications.

Background AGT (angiotensinogen) synthesis occurs in renal proximal tubular epithelial cells, independent from systemic AGT , as a component of the intrarenal renin-angiotensin system. We investigated urinary AGT , as a biomarker for renin-angiotensin system activation, and electrolyte concentrations, in relation to glomerular volume, as a proxy for glomerular endotheliosis in renal biopsy tissue from pregnant normotensive control and hypertensive women. Methods and Results Urine samples were collected from normotensive control (n=10), gestational hypertensive (n=6), and pre-eclamptic (n=16) women at the time a renal biopsy was obtained. Samples were collected from Lund University Hospital between November 1999 and June 2001. Urinary AGT , potassium, and sodium were measured, normalized to urinary creatinine. Mean glomerular volume was estimated from biopsy sections. AGT protein expression and localization were assessed in renal biopsies by immunohistochemistry. Urinary AGT concentrations were higher in hypertensive pregnancies (median, gestational hypertension: 11.3 ng/mmol [interquartile range: 2.8-13.6]; preeclampsia: 8.4 ng/mmol [interquartile range: 4.2-29.1]; normotensive control: 0.6 ng/mmol [interquartile range: 0.4-0.8]; P<0.0001) and showed a positive relationship with estimated mean glomerular volume. Urinary potassium strongly correlated with urinary AGT ( P<0.0001). Although numbers were small, AGT protein was found in both glomeruli and proximal tubules in normotensive control but was present only in proximal tubules in women with hypertensive pregnancy. Conclusions This study shows that pregnant women with gestational hypertension or preeclampsia have increased urinary AGT and potassium excretion associated with signs of glomerular swelling. Our data suggest that the kidneys of women with hypertensive pregnancies and endotheliosis have inappropriate intrarenal renin-angiotensin system activation, which may contribute toward the pathogenesis of hypertension and renal injury.

Diagnostic Indicators of Superimposed Preeclampsia in Women With CKD.

INTRODUCTION: Diagnosis of superimposed preeclampsia in women with chronic kidney disease (CKD) is complicated by the presence of hypertension and proteinuria due to renal disease. The aims of this study were to determine mechanistic links between superimposed preeclampsia and renin-angiotensin system activation, endothelial pathology, complement dysfunction, and tubular injury, and to explore the role of diagnostic indicators of superimposed preeclampsia. METHODS: Plasma and urinary biomarkers derived from the renin-angiotensin system (active renin, angiotensinogen), endothelial glycocalyx (hyaluronan, intercellular adhesion molecule, vascular cell adhesion molecule [VCAM], P-selectin, E-selectin), complement activation (C3a, C5a, complement factor H, C5b-9), and tubular injury (kidney injury molecule-1, urinary lipocalin-2) were quantified in 60 pregnant women with CKD including 15 women at the time of superimposed preeclampsia diagnosis and 45 women who did not develop superimposed preeclampsia, 18 women with preeclampsia, and 20 normal pregnancies. Correlation with placental growth factor was assessed. RESULTS: Plasma concentrations of hyaluronan (67.5 ng/ml vs. 27.5 ng/ml, P = 0.0017, receiver operating characteristic area 0.80) and VCAM (1132 ng/ml vs. 659 ng/ml, P < 0.0001, receiver operating characteristic area 0.86) distinguished women with CKD and superimposed preeclampsia from those without superimposed preeclampsia, and correlated with placental growth factor concentration. The diagnostic discrimination of markers of the renin-angiotensin system was reduced by adjustment for chronic hypertension, antihypertensive drug use, and black ethnicity. Other markers offered limited or no diagnostic discrimination for superimposed preeclampsia. CONCLUSION: This study suggests that endothelial dysfunction contributes to the pathophysiology of superimposed preeclampsia and a diagnostic role for plasma hyaluronan and VCAM is hypothesized.

Postpartum evaluation of cardiovascular disease risk for women with pregnancies complicated by hypertension.

OBJECTIVES: Postpartum stratification of cardiovascular risk for women with pregnancies complicated by pre-eclampsia is challenging. Our aim was to identify potential clinical and biomarker predictors of future cardiovascular risk at six weeks postpartum in women with hypertensive pregnancies. STUDY DESIGN: Prospective longitudinal cohort. MAIN OUTCOME MEASURES: Ten year-Framingham cardiovascular risk scores were calculated for 477 women (94 with gestational hypertension, 288 with pre-eclampsia, 30 with superimposed pre-eclampsia, 51 with chronic hypertension, 14 women with uncomplicated pregnancies). B-type natriuretic peptide (BNP), neutrophil gelatinase-associated lipocalin (NGAL) and placental growth factor (PlGF) were quantified at six weeks postpartum. RESULTS: Framingham cardiovascular risk scores were not higher in women with pregnancies complicated by pre-eclampsia than healthy controls, nor were scores higher in women with pre-existing chronic hypertension complicated with superimposed pre-eclampsia compared with those without superimposed pre-eclampsia. Women with gestational hypertension had higher risk scores than women with pre-eclampsia and healthy controls. Established risk factors of cardiovascular disease including diastolic blood pressure and previously diagnosed chronic hypertension were associated with higher scores, and African ethnicity, parity and estimated glomerular filtration rate also were independently associated with higher Framingham risk scores at six weeks postpartum. PlGF, BNP and NGAL concentrations were not associated with Framingham cardiovascular risk scores after adjustment for independent variables. CONCLUSIONS: A history of pre-eclampsia or superimposed pre-eclampsia in most recent pregnancy was not associated with elevated Framingham risk score at six weeks postpartum. Established clinical predictors may enable risk stratification at six weeks postpartum, which are not enhanced by the biomarkers included in this study.

Born from pre-eclamptic pregnancies predisposes infants to altered cortisol metabolism in the first postnatal year.

Pre-eclampsia leads to disturbed fetal organ development, including metabolic syndrome, attributed to altered pituitary-adrenal feedback loop. We measured cortisol metabolites in infants born from pre-eclamptic and normotensive women and hypothesised that glucocorticoid exposure would be exaggerated in the former. Twenty-four hour urine was collected from infants at months 3 and 12. Cortisol metabolites and apparent enzyme activities were analysed by gas chromatography-mass spectrometry. From 3 to 12 months, excretion of THS, THF and pregnandiol had risen in both groups; THF also rose in the pre-eclamptic group. No difference was observed with respect to timing of the visit or to hypertensive status for THE or total F metabolites (P>0.05). All apparent enzymes activities, except 17α-hydroxylase, were lower in infants at 12 compared to 3 months in the normotensive group. In the pre-eclamptic group, only 11ß-HSD activities were lower at 12 months.17α-hydroxylase and 11ß-HSD activities of tetrahydro metabolites were higher in the pre-eclamptic group at 3 months (P<0.05). 11ß-hydroxylase activity increased in the pre-eclamptic group at 12 months. Cortisol excretion, determined by increased 11ß-hydroxylase, compensates for high 11ß-HSD-dependent cortisol degradation at 3 months and at 12 months counterbalances the reduced cortisol substrate availability in infants born from pre-eclamptic mothers.

Association between maternal micronutrient status, oxidative stress, and common genetic variants in antioxidant enzymes at 15 weeks׳ gestation in nulliparous women who subsequently develop preeclampsia.

Preeclampsia is a pregnancy-specific condition affecting 2-7% of women and a leading cause of perinatal and maternal morbidity and mortality. Deficiencies of specific micronutrient antioxidant activities associated with copper, selenium, zinc, and manganese have previously been linked to preeclampsia at the time of disease. Our aims were to investigate whether maternal plasma micronutrient concentrations and related antioxidant enzyme activities are altered before preeclampsia onset and to examine the dependence on genetic variations in these antioxidant enzymes. Predisease plasma samples (15±1 weeks׳ gestation) were obtained from women enrolled in the international Screening for Pregnancy Endpoints (SCOPE) study who subsequently developed preeclampsia (n=244) and from age- and BMI-matched normotensive controls (n=472). Micronutrient concentrations were measured by inductively coupled plasma mass spectrometry; associated antioxidant enzyme activities, selenoprotein-P, ceruloplasmin concentration and activity, antioxidant capacity, and markers of oxidative stress were measured by colorimetric assays. Sixty-four tag-single-nucleotide polymorphisms (SNPs) within genes encoding the antioxidant enzymes and selenoprotein-P were genotyped using allele-specific competitive PCR. Plasma copper and ceruloplasmin concentrations were modestly but significantly elevated in women who subsequently developed preeclampsia (both P<0.001) compared to controls (median (IQR), copper, 1957.4 (1787, 2177.5) vs 1850.0 (1663.5, 2051.5) µg/L; ceruloplasmin, 2.5 (1.4, 3.2) vs 2.2 (1.2, 3.0) µg/ml). There were no differences in other micronutrients or enzymes between groups. No relationship was observed between genotype for SNPs and antioxidant enzyme activity. This analysis of a prospective cohort study reports maternal micronutrient concentrations in combination with associated antioxidant enzymes and SNPs in their encoding genes in women at 15 weeks׳ gestation that subsequently developed preeclampsia. The modest elevation in copper may contribute to oxidative stress, later in pregnancy, in those women that go on to develop preeclampsia. The lack of evidence to support the hypothesis that functional SNPs influence antioxidant enzyme activity in pregnant women argues against a role for these genes in the etiology of preeclampsia.