The therapeutic potential of antioxidants, ER chaperones, NO and H2S donors, and statins for treatment of preeclampsia

Current Approaches and Innovations in Managing Preeclampsia: Highlighting Maternal Health Disparities

Preeclampsia (PE) is a major cause of maternal mortality and morbidity, affecting 3-6% of pregnancies worldwide and ranking among the top six causes of maternal deaths in the U.S. PE typically develops after 20 weeks of gestation and is characterized by new-onset hypertension and/or end-organ dysfunction, with or without proteinuria. Current management strategies for PE emphasize early diagnosis, blood pressure control, and timely delivery. For prevention, low-dose aspirin (81 mg/day) is recommended for high-risk women between 12 and 28 weeks of gestation. Magnesium sulfate is also advised to prevent seizures in preeclamptic women at risk of eclampsia. Emerging management approaches include antiangiogenic therapies, hypoxia-inducible factor suppression, statins, and supplementation with CoQ10, nitric oxide, and hydrogen sulfide donors. Black women are at particularly high risk for PE, potentially due to higher rates of hypertension and cholesterol, compounded by healthcare disparities and possible genetic factors, such as the APOL1 gene. This review explores current and emerging strategies for managing PE and addresses the underlying causes of health disparities, offering potential solutions to improve outcomes.

Exploring the Lifeline: Unpacking the Complexities of Placental Vascular Function in Normal and Preeclamptic Pregnancies

The proper development and function of the placenta are essential for the success of pregnancy and the well-being of both the fetus and the mother. Placental vascular function facilitates efficient fetal development during pregnancy by ensuring adequate gas exchange with low vascular resistance. This review focuses on how placental vascular function can be compromised in the pregnancy pathology preeclampsia, and conversely, how placental vascular dysfunction might contribute to this condition. While the maternal endothelium is widely recognized as a key focus in preeclampsia research, this review emphasizes the importance of understanding how this condition affects the development and function of the fetal placental vasculature. The placental vascular bed, consisting of microvasculature and macrovasculature, is discussed in detail, as well as structural and functional changes associated with preeclampsia. The complexity of placental vascular reactivity and function, its mediators, its impact on placental exchange and blood distribution, and how these factors are most affected in early-onset preeclampsia are further explored. These factors include foremost lipoproteins and their cargo, oxygen levels and oxidative stress, biomechanics, and shear stress. Challenges in studying placental pathophysiology are discussed, highlighting the necessity of innovative research methodologies, including ex vivo experiments, in vivo imaging tools, and computational modeling. Finally, an outlook on the potential of drug interventions targeting the placental endothelium to improve placental vascular function in preeclampsia is provided. Overall, this review highlights the need for further research and the development of models and tools to better understand and address the challenges posed by preeclampsia and its effects on placental vascular function to improve short- and long-term outcomes for the offspring of preeclamptic pregnancies. © 2024 American Physiological Society. Compr Physiol 14:5763-5787, 2024.

Hydrogen sulfide and its role in female reproduction

Hydrogen sulfide (H2S) is a gaseous signaling molecule produced in the body by three enzymes: cystathionine-β-synthase (CBS), cystathionine-γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3-MST). H2S is crucial in various physiological processes associated with female mammalian reproduction. These include estrus cycle, oocyte maturation, oocyte aging, ovulation, embryo transport and early embryo development, the development of the placenta and fetal membranes, pregnancy, and the initiation of labor. Despite the confirmed presence of H2S-producing enzymes in all female reproductive tissues, as described in this review, the exact mechanisms of H2S action in these tissues remain in most cases unclear. Therefore, this review aims to summarize the knowledge about the presence and effects of H2S in these tissues and outline possible signaling pathways that mediate these effects. Understanding these pathways may lead to the development of new therapeutic strategies in the field of women's health and perinatal medicine.

Protein persulfidation: Rewiring the hydrogen sulfide signaling in cell stress response

The past few decades have witnessed significant progress in the discovery of hydrogen sulfide (H₂S) as a ubiquitous gaseous signaling molecule in mammalian physiology, akin to nitric oxide and carbon monoxide. As the third gasotransmitter, H₂S is now known to exert a wide range of physiological and cytoprotective functions in the biological systems. However, endogenous H₂S concentrations are usually low, and its potential biologic mechanisms responsible have not yet been fully clarified. Recently, a growing body of evidence has demonstrated that protein persulfidation, a posttranslational modification of cysteine residues (RSH) to persulfides (RSSH) elicited by H₂S, is a fundamental mechanism of H₂S-mediated signaling pathways. Persulfidation, as a biological switch for protein function, plays an important role in the maintenance of cell homeostasis in response to various internal and external stress stimuli and is also implicated in numerous diseases, such as cardiovascular and neurodegenerative diseases and cancer. In this review, the biological significance of protein persulfidation by H₂S in cell stress response is reviewed providing a framework for understanding the multifaceted roles of H₂S. A mechanism-guided perspective can help open novel avenues for the exploitation of therapeutics based on H₂S-induced persulfidation in the context of diseases.

miR-515-5p suppresses trophoblast cell invasion and proliferation through XIAP regulation in preeclampsia

MicroRNAs (miRNAs) are non-coding small RNA molecules that can be secreted into the circulation and which exist in remarkably stable forms. Circulating miRNAs regulate numerous biological process and are aberrantly expressed in pathological conditions. Differentially expressed circulating miRNAs have received attention as potential biomarkers for many diseases. In this study, we revealed that miR-515-5p was significantly upregulated in maternal serum from preeclampsia patients in comparison to normal pregnant women. Bioinformatics prediction and a dual-luciferase reporter gene assay revealed that miR-515-5p directly targets the X-linked inhibitor of apoptosis protein (XIAP) 3'-untranslated region. In addition, the overexpression of miR-515-5p inhibited the proliferation and invasion of HTR-8/SVneo trophoblast cells. The decreased XIAP expression and reduced epithelial-mesenchymal transition (EMT) were observed in the preeclamptic placenta. Collectively, miR-515-5p may play critical roles in the pathogenesis of preeclampsia through suppression of XIAP, and serum miR-515-5p may act as a potential biomarker for preeclampsia.

Maternal obesity: new placental paradigms unfolded

The prevalence of maternal obesity is increasing at an alarming rate, and is providing a major challenge for obstetric practice. Adverse effects on maternal and fetal health are mediated by complex interactions between metabolic, inflammatory, and oxidative stress signaling in the placenta. Endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR) are common downstream pathways of cell stress, and there is evidence that this conserved homeostatic response may be a key mediator in the pathogenesis of placental dysfunction. We summarize the current literature on the placental cellular and molecular changes that occur in obese women. A special focus is cast onto placental ER stress in obese pregnancy, which may provide a novel link for future investigation.

Hypertensive Disorders of Pregnancy and Fetal Growth Restriction: Clinical Characteristics and Placental Lesions and Possible Preventive Nutritional Targets

Background: The purpose of this study was to describe the placental lesions in pregnancies complicated by hypertensive disorders (HDP) and/or fetal growth restriction (FGR) and in uneventful control pregnancies. Methods: This is a case control study that included singleton pregnancies with HDP and normally grown fetus (HDP-AGA fetus), with HDP and FGR, early FGR, late FGR, and uneventful pregnancies. Feto-placental Doppler velocimetry and sFlt-1/PlGF ratio were performed. Placental histology was evaluated blinded according to the Amsterdam Consensus criteria. Results: Placental lesions with maternal vascular malperfusion (MVM) were significantly more frequent in HDP-FGR and early FGR (92% and 83%). MVM were significantly associated with abnormal feto-placental Doppler parameters, especially in early FGR. Delayed villous maturation (DVM) was associated with late FGR (83%). HDP-AGA fetus cases presented a heterogeneous pattern of placental lesions, including 60% of cases with MVM, but were not associated with abnormal Doppler feto-placental velocimetry. Conclusions: We found a prevalence of placental maternal vascular malperfusion in HDP-FGR and early FGR groups. These lesions were also associated with abnormal, anti-, and angiogenic markers. Conversely HDP-AGA fetus and late FGR presented more heterogeneous placental lesions not severe enough to cause feto-placental Doppler anomalies. These conditions are likely associated with different etiologies, such as maternal pre-pregnancy risk factors for metabolic syndrome. These findings suggest a possible preventive nutritional approach in addition to low-dose aspirin in pregnant women with predisposing factors for HDP-AGA fetuses and late FGR.

The importance of nutrition in pregnancy and lactation: lifelong consequences

Most women in the United States do not meet the recommendations for healthful nutrition and weight before and during pregnancy. Women and providers often ask what a healthy diet for a pregnant woman should look like. The message should be “eat better, not more.” This can be achieved by basing diet on a variety of nutrient-dense, whole foods, including fruits, vegetables, legumes, whole grains, healthy fats with omega-3 fatty acids that include nuts and seeds, and fish, in place of poorer quality highly processed foods. Such a diet embodies nutritional density and is less likely to be accompanied by excessive energy intake than the standard American diet consisting of increased intakes of processed foods, fatty red meat, and sweetened foods and beverages. Women who report “prudent” or “health-conscious” eating patterns before and/or during pregnancy may have fewer pregnancy complications and adverse child health outcomes. Comprehensive nutritional supplementation (multiple micronutrients plus balanced protein energy) among women with inadequate nutrition has been associated with improved birth outcomes, including decreased rates of low birthweight. A diet that severely restricts any macronutrient class should be avoided, specifically the ketogenic diet that lacks carbohydrates, the Paleo diet because of dairy restriction, and any diet characterized by excess saturated fats. User-friendly tools to facilitate a quick evaluation of dietary patterns with clear guidance on how to address dietary inadequacies and embedded support from trained healthcare providers are urgently needed.

Recent evidence has shown that although excessive gestational weight gain predicts adverse perinatal outcomes among women with normal weight, the degree of prepregnancy obesity predicts adverse perinatal outcomes to a greater degree than gestational weight gain among women with obesity. Furthermore, low body mass index and insufficient gestational weight gain are associated with poor perinatal outcomes. Observational data have shown that first-trimester gain is the strongest predictor of adverse outcomes. Interventions beginning in early pregnancy or preconception are needed to prevent downstream complications for mothers and their children. For neonates, human milk provides personalized nutrition and is associated with short- and long-term health benefits for infants and mothers. Eating a healthy diet is a way for lactating mothers to support optimal health for themselves and their infants.

Elevated expression of galectin-3, thioredoxin and thioredoxin interacting protein in preeclampsia

OBJECTIVES

Preeclampsia (PE) is a pregnancy-related syndrome characterized by the onset of hypertension and proteinuria that can lead to end-organ dysfunction. Galectin-3 (Gal-3) is involved in cell growth, differentiation, inflammation and fibrosis. Thioredoxin (TXN) acts as antioxidant enzyme in several cellular processes, regulating inflammation and inhibiting apoptosis. TXNIP is an endogenous inhibitor of TXN. We evaluated changes in the inflammatory response of Gal-3, TXN, and TXNIP at the level of maternal blood, placenta, and umbilical cord blood of women with PE.

STUDY DESIGN

Ten women with PE and 20 with normal pregnancy (NP) were recruited during admission for delivery. Blood samples were obtained from parturients and umbilical cords, and placental tissue for analysis.

RESULTS

Gal-3 and TXNIP mRNA expression were higher in maternal plasma in PE group compared to NP and were lower in cord blood plasma and placentas in the PE group. In the PE group, TXN/TXNIP mRNA ratio was higher in cord blood plasma (2.07) compared to maternal plasma (1.09). TXN/TXNIP placental protein ratio was similar between PE (0.89) and NP (0.79). ELISA demonstrated that Gal-3 levels in maternal serum were significantly higher in the PE vs. the NP group.

CONCLUSIONS

Pro-inflammatory changes were expressed by high Gal-3 and TXNIP mRNA in maternal blood of PE women, but not in their placental and cord blood samples. These findings may imply that the placenta has a role in protecting the fetus from the damages of inflammatory response, which is more common in PE than in NP.

Hydrogen sulfide content in pregnant women with preeclampsia in late gestation and their newborns

We examined 70 women who were 22-40 weeks pregnant and their newborns. Of these, 15 women with moderate PE made up group 1, 22 women with severe PE-group 2, and 55 women with uncomplicated pregnancy without hypertensive disorders - the control group. Blood was collected from women when they were admitted to the clinic, and blood was taken from newborns for 3-5 days of life. The concentration of hydrogen sulfide was determined by the method of K. Qu et al [17]. There was a decrease in the level of hydrogen sulfide in the blood serum of women whose pregnancy was complicated by severe preeclampsia. In newborns born to mothers with preeclampsia, an increase in the concentration of hydrogen sulfide was detected in the blood, which is probably a compensatory reaction aimed at restoring vascular homeostasis during early postnatal adaptation.

Hypoxia and the integrated stress response promote pulmonary hypertension and preeclampsia: Implications in drug development

Chronic hypoxia is a common cause of pulmonary hypertension, preeclampsia, and intrauterine growth restriction (IUGR). The molecular mechanisms underlying these diseases are not completely understood. Chronic hypoxia may induce the generation of reactive oxygen species (ROS) in mitochondria, promote endoplasmic reticulum (ER) stress, and result in the integrated stress response (ISR) in the pulmonary artery and uteroplacental tissues. Numerous studies have implicated hypoxia-inducible factors (HIFs), oxidative stress, and ER stress/unfolded protein response (UPR) in the development of pulmonary hypertension, preeclampsia and IUGR. This review highlights the roles of HIFs, mitochondria-derived ROS and UPR, as well as their interplay, in the pathogenesis of pulmonary hypertension and preeclampsia, and their implications in drug development.

Elevated Levels of Soluble Axl (sAxl) Regulates Key Angiogenic Molecules to Induce Placental Endothelial Dysfunction and a Preeclampsia-Like Phenotype

Preeclampsia (PE), a severe pregnancy-specific syndrome, is characterized by impaired placental angiogenesis. Although the pathogenesis of this condition remains largely unclear, vascular systemic endothelial injury is thought to be the common contributing factor. Soluble Axl (sAxl), a biomarker of endothelial dysfunction, is known to be abnormally increased in a variety of diseases associated with vascular injury. In a previous study, we found that the plasma levels of sAxl were significantly higher in PE with severe features (sPE) than in pregnant women who did not have PE. The current study aimed to further explore the potential role of sAxl in vascular injury in patients with sPE. We found that the upregulation of sAxl in maternal plasma was positively correlated with the plasma levels of sFlt-1 and negatively correlated with placental NO synthase (eNOS) in women with sPE. Furthermore, elevated levels of sAxl suppressed proliferation and endothelial tube formation and promoted cytotoxicity in human umbilical vein endothelial cells (HUVECs) through the downregulation of p-Akt, p-p70S6K, p-mTOR, and Grb2. Subsequently, we established a pregnant rat model with PE-like characteristics by injecting pregnant rats with an adenovirus expressing sAxl. These rats exhibited a typical PE-like phenotype, including increased blood pressure, proteinuria, and fetal growth restriction, along with abnormal placental and fetal renal morphology. In conclusion, our study demonstrated the role of sAxl in systemic vascular injury through the regulation of the expression of key molecules of angiogenesis and described its potential contribution to the development of sPE.

Impact of resveratrol-mediated increase in uterine artery blood flow on fetal haemodynamics, blood pressure and oxygenation in sheep

NEW FINDINGS

What is the central question of this study? Uterine artery blood flow helps to maintain fetal oxygen and nutrient delivery. We investigated the effects of increased uterine artery blood flow mediated by resveratrol on fetal growth, haemodynamics, blood pressure regulation and oxygenation in pregnant sheep. What is the main finding and its importance? Fetuses from resveratrol-treated ewes were significantly larger and exhibited a haemodynamic profile that might promote peripheral growth. Absolute uterine artery blood flow was positively correlated with umbilical vein oxygen saturation, absolute fetal oxygen delivery and fetal growth. Increasing uterine artery blood flow with compounds such as resveratrol might have clinical significance for pregnancy conditions in which fetal growth and oxygenation are compromised.

ABSTRACT

High placental vascular resistance hinders uterine artery (UtA) blood flow and fetal substrate delivery. In the same group of animals as the present study, we have previously shown that resveratrol (RSV) increases UtA blood flow, fetal weight and oxygenation in an ovine model of human pregnancy. However, the mechanisms behind changes in growth and the effects of increases in UtA blood flow on fetal circulatory physiology have yet to be investigated. Twin-bearing ewes received s.c. vehicle (VEH, n = 5) or RSV (n = 6) delivery systems at 113 days of gestation (term = 150 days). Magnetic resonance imaging was performed at 123-124 days to quantify fetal volume, blood flow and oxygen saturation of major fetal vessels. At 128 days, i.v. infusions of sodium nitroprusside and phenylephrine were administered to study the vascular tone of the fetal descending aorta. Maternal RSV increased fetal body volume (P = 0.0075) and weight (P = 0.0358), with no change in brain volume or brain weight. There was a positive relationship between absolute UtA blood flow and umbilical vein oxygen saturation, absolute fetal oxygen delivery and combined fetal twin volume (all P ≤ 0.05). There were no differences between groups in fetal haemodynamics or blood pressure regulation except for higher blood flow to the lower body in RSV fetuses (P = 0.0170). The observed increase in fetal weight might be helpful in pregnancy conditions in which fetal growth and oxygen delivery are compromised. Further preclinical investigations on the mechanism(s) accounting for these changes and the potential to improve growth in complicated pregnancies are warranted.

Adaptations of the human placenta to hypoxia: opportunities for interventions in fetal growth restriction

BACKGROUND

The placenta is the functional interface between the mother and the fetus during pregnancy, and a critical determinant of fetal growth and life-long health. In the first trimester, it develops under a low-oxygen environment, which is essential for the conceptus who has little defense against reactive oxygen species produced during oxidative metabolism. However, failure of invasive trophoblasts to sufficiently remodel uterine arteries toward dilated vessels by the end of the first trimester can lead to reduced/intermittent blood flow, persistent hypoxia and oxidative stress in the placenta with consequences for fetal growth. Fetal growth restriction (FGR) is observed in ∼10% of pregnancies and is frequently seen in association with other pregnancy complications, such as preeclampsia (PE). FGR is one of the main challenges for obstetricians and pediatricians, as smaller fetuses have greater perinatal risks of morbidity and mortality and postnatal risks of neurodevelopmental and cardio-metabolic disorders.

OBJECTIVE AND RATIONALE

The aim of this review was to examine the importance of placental responses to changing oxygen environments during abnormal pregnancy in terms of cellular, molecular and functional changes in order to highlight new therapeutic pathways, and to pinpoint approaches aimed at enhancing oxygen supply and/or mitigating oxidative stress in the placenta as a mean of optimizing fetal growth.

SEARCH METHODS

An extensive online search of peer-reviewed articles using PubMed was performed with combinations of search terms including pregnancy, placenta, trophoblast, oxygen, hypoxia, high altitude, FGR and PE (last updated in May 2020).

OUTCOMES

Trophoblast differentiation and placental establishment are governed by oxygen availability/hypoxia in early pregnancy. The placental response to late gestational hypoxia includes changes in syncytialization, mitochondrial functions, endoplasmic reticulum stress, hormone production, nutrient handling and angiogenic factor secretion. The nature of these changes depends on the extent of hypoxia, with some responses appearing adaptive and others appearing detrimental to the placental support of fetal growth. Emerging approaches that aim to increase placental oxygen supply and/or reduce the impacts of excessive oxidative stress are promising for their potential to prevent/treat FGR.

WIDER IMPLICATIONS

There are many risks and challenges of intervening during pregnancy that must be considered. The establishment of human trophoblast stem cell lines and organoids will allow further mechanistic studies of the effects of hypoxia and may lead to advanced screening of drugs for use in pregnancies complicated by placental insufficiency/hypoxia. Since no treatments are currently available, a better understanding of placental adaptations to hypoxia would help to develop therapies or repurpose drugs to optimize placental function and fetal growth, with life-long benefits to human health.

Current Researches, Rationale, Plausibility, and Evidence Gaps on Metformin for the Management of Hypertensive Disorders of Pregnancy

Hypertensive disorders of pregnancy (HDP) are a group of morbid pregnancy complications, with preeclampsia (PE) being the most common subclassification among them. PE affects 2%–8% of pregnancies globally and threatens maternal and fetal health seriously. However, the only effective treatment of PE to date is the timely termination of pregnancy, albeit with increased perinatal risks. Hence, more emerging therapies for PE management are in urgent need. Originally introduced as the first-line therapy for type 2 diabetes mellitus, metformin (MET) has now been found in clinical trials to significantly reduce the incidence of gestational hypertension and PE in pregnant women with PE-related risks, including but not limited to pregestational diabetes mellitus, gestational diabetes mellitus, polycystic ovary syndrome, or obesity. Additionally, existing clinical data have preliminarily ensured the safety of taking MET during human pregnancies. Relevant lab studies have indicated that the underlying mechanism includes angiogenesis promotion, endothelial protection, anti-inflammatory effects, and particularly protective effects on trophoblast cells against the risk factors, which are beneficial to placental development. Together with its global availability, easy administration, and low cost, MET is expected to be a promising option for the prevention and treatment of PE. Nevertheless, there are still some limitations in current studies, and the design of the relevant research scheme is supposed to be further improved in the future. Herein, we summarize the relevant clinical and experimental researches to discuss the rationale, safety, and feasibility of MET for the management of HDP. At the end of the article, gaps in current researches are proposed. Concretely, experimental MET concentration and PE models should be chosen cautiously. Besides, the clinical trial protocol should be further optimized to evaluate the reduction in the prevalence of PE as a primary endpoint. All of those evidence gaps may be of guiding significance to improve the design of relevant experiments and clinical trials in the future.

Ovine uterine artery hydrogen sulfide biosynthesis in vivo: effects of ovarian cycle and pregnancy†

Uterine vasodilation dramatically increases during the follicular phase of the estrous cycle and pregnancy, which are estrogen-dominant physiological states. Uterine vasodilation is believed to be mainly controlled by local uterine artery (UA) production of vasodilators and angiogenic factors. The extremely potent vasodilator and proangiogenic hydrogen sulfide (H2S) is synthesized via metabolizing L-cysteine by cystathionine β-synthase (CBS) and cystathionine γ-lyase (CTH). This study was designed to determine if UA H2S production increases with augmented expression and/or activity of CBS and/or CTH during the ovarian cycle and pregnancy in sheep. Uterine arteries from intact nonpregnant (NP) luteal and follicular phase and late (130-135 days, term ≈ 145 days) pregnant (P) ewes were collected; endothelium-enriched proteins (UAendo) and endothelium-denuded smooth muscle (UAvsm) were mechanically prepared for accessing CBS and CTH proteins by immunoblotting; their cellular localization was determined by semi-quantitative immunofluorescence microscopy. H2S production was measured by the methylene blue assay. Immunoblotting revealed that CBS but not CTH protein was greater in P > > > NP follicular > luteal UAendo and UAvsm (P < 0.001). H2S production was greater in P > > > NP UAendo and UAvsm (P < 0.01). Pregnancy-augmented UAendo and UAvsm H2S production was inhibited by the specific CBS but not CTH inhibitor. CBS and CTH proteins were localized to both endothelium and smooth muscle; however, only CBS protein was significantly greater in P vs NP UA endothelium and smooth muscle. Thus, ovine UA H2S production is significantly augmented via selectively upregulating endothelium and smooth muscle CBS during the follicular phase and pregnancy in vivo.

Exploring the beneficial effects and possible mechanisms of repeated episodes of whole-body hypoxic perconditioning in rat model of preeclampsia

AIM

The study explored the beneficial effects of repeated episodes of whole body hypoxic perconditioning (WHPC) on preeclampsia (PE)-like symptoms in rats.

MATERIAL AND METHODS

PE was induced by administration of L-NAME (75 mg/kg) and WHPC was performed by exposing rats to low O₂ (8%) and normal O₂ of 10 min each in four alternate cycles.

RESULTS

L-NAME induced PE like symptoms in rats along with a decrease in the cystathionine-β-synthase (CBS) activity in the placental tissue, plasma levels of H₂S and NO metabolites in pregnant rats. Two (GD9, GD14) and three episodes (GD9, GD14 and GD18) of WHPC improved PE-like symptoms with an increase in CBS activity and H₂S levels. CBS inhibitor, amino-oxyacetic acid abolished the beneficial effects of three episodes of WHPC; while H₂S donor, 4-methylbenzenecarbothioamide, 4-MBC attenuated PE-like symptoms.

CONCLUSION

WHPC attenuates L-NAME-induced PE-like symptoms due to increase in CBS activity and H₂S-production.

Mangiferin ameliorates placental oxidative stress and activates PI3K/Akt/mTOR pathway in mouse model of preeclampsia

Preeclampsia is an inflammatory disease which can induce oxidative stress in placenta. Oxidative stress in preeclampsia is regulated by the phosphatidylinositol-3-kinase/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway. Mangiferin, an anti-oxidative molecule, is reported to ameliorate oxidative stress in the kidney and brain through activating the PI3K/Akt/mTOR pathway. We aimed to investigate the effects of mangiferin in a mouse model of preeclampsia, which was induced by phosphatidylserine/dioleoyl-phosphatidycholine (PS/PC) from day 5 to 17 of pregnancy. The female pregnant mice were divided into five groups according to drug treatment. Animals received mangiferin orally at doses of 10, 20, 40 mg/kg/day from day 0.5 to 17. In preeclampsia mouse model, elevated systolic blood pressure and proteinuria were ameliorated by mangiferin treatment. Mangiferin attenuated fms-like tyrosine kinase-1 and placental growth factor expression and oxidative stress in both blood and placenta of preeclampsia mice. The suppressed PI3K/Akt/mTOR pathway in placenta was activated by mangiferin treatment. This study demonstrates that mangiferin ameliorates placental oxidative stress and activates PI3K/Akt/mTOR pathway in a mouse model of preeclampsia.

Endoplasmic reticulum stress may activate NLRP3 inflammasomes via TXNIP in preeclampsia

Preeclampsia (PE) development is often associated with placental immune and inflammatory dysregulation, as well as endoplasmic reticulum (ER) stress. However, the mechanisms linking ER stress and inflammatory dysregulation to PE have not been elucidated. It has been reported that thioredoxin-interacting protein (TXNIP), which can bind with and activate the NLR family pyrin domain containing 3 (NLRP3) inflammasome, is a key point in immune regulation. Recent experimental evidence suggests that activated NLRP3 inflammasomes can activate interleukin-1β (IL-1β) production in the placenta of patients with PE. The objective of the current study was to explore if TXNIP plays a critical signaling role linking ER stress with NLRP3 inflammasome activation in PE. We hypothesized that ER stress would induce TXNIP production, which would bind with NLRP3 inflammasomes to activate IL-1β production. These cells showed a higher protein level of NLRP3 and IL-1β, as well as a higher enzymatic activity of caspase-1, indicating enhanced inflammatory dysregulation and ER stress. Cells transfected with TXNIP siRNA showed reduced NLRP3 inflammasome activation. Cells treated with 4-phenylbutyric acid, an inhibitor of ER stress, showed a similar result. Outgrowth of the explant with TXNIP lentivirus in H/R or tunicamycin (inducers of ER stress) was also measured to verify our hypothesis. These findings demonstrated that TXNIP could influence inflammatory dysregulation by mediating ER stress and NLRP3 inflammasome activation in PE. This novel mechanism may further explain the inflammation observed at the maternal-fetal interface, which leads to placental dysfunction in a patient with PE.

Role of vitamin D in influencing angiogenesis in preeclampsia

Objective: Vitamin D plays a key role during pregnancy and is involved in implantation and maintenance of pregnancy. Its deficiency is associated with pregnancy complications like preeclampsia, characterized by abnormal angiogenesis.Method: The current article summarises studies examining the role of vitamin D in pregnancy, with special emphasis on preeclampsia.Results and conclusion: An imbalance in pro- and anti-angiogenic factors is reported in women with preeclampsia. Cell culture studies have demonstrated that vitamin D can influence the process of angiogenesis. However, the role of maternal vitamin D in influencing placental angiogenesis in preeclampsia is unclear and needs to be explored.

Pre-eclampsia: pathophysiology and clinical implications

Pre-eclampsia is a common disorder that particularly affects first pregnancies. The clinical presentation is highly variable but hypertension and proteinuria are usually seen. These systemic signs arise from soluble factors released from the placenta as a result of a response to stress of syncytiotrophoblast. There are two sub-types: early and late onset pre-eclampsia, with others almost certainly yet to be identified. Early onset pre-eclampsia arises owing to defective placentation, whilst late onset pre-eclampsia may center around interactions between normal senescence of the placenta and a maternal genetic predisposition to cardiovascular and metabolic disease. The causes, placental and maternal, vary among individuals. Recent research has focused on placental-uterine interactions in early pregnancy. The aim now is to translate these findings into new ways to predict, prevent, and treat pre-eclampsia.

The effect of statin therapy on endoplasmic reticulum stress

The endoplasmic reticulum (ER) is critical in protein processing and particularly in ensuring that proteins undergo their correct folding to exert their functionality. What is becoming increasingly clear is that the ER may undergo increasing stress brought about by nutrient deprivation, hypoxia, oxidized lipids, point mutations in secreted proteins, cellular differentiation or significant deviation from metabolic set points, and loss of Ca²⁺ homeostasis, with detrimental effects on ER-resident calcium-dependent chaperones, alone or in combination. This results in the unfolded protein response (UPR) that is a repair mechanism to limit the formation of newly damaged proteins until ER homeostasis is restored, though may result in increased cell death. ER stress has been shown to be implicated in a variety of diseases. Statins are well-known cholesterol-lowering drugs and have been extensively reported to possess beneficial cholesterol-independent effects in a variety of human diseases. This review focuses on the concept of ER stress, the underlying molecular mechanisms and their relationship to the pathophysiology and, finally, the role of statins in moderating ER stress and UPR.

The expression of serum sEGFR, sFlt-1, sEndoglin and PLGF in preeclampsia

The objective of this study was to investigate soluble epidermal growth factor receptor (sEGFR), soluble vascular endothelial growth factor receptor 1 (sFlt-1), soluble endoglin (sEndoglin) and placenta growth factor (PLGF) concentrations in normotensive, preterm and term preeclamptic pregnancies' serum and thus to specify the clinical utility of these biochemical markers in monitoring severity and intrauterine growth retardation of preterm preeclampsia. 172 pregnant women were divided into the following groups: preterm preeclampsia, preterm control, term preeclampsia and term control. Preterm preeclampsia patients were stratified with severe feature (n = 50) and without severe feature (n = 22). sEGFR, sEndoglin and PLGF were assessed using Luminex multiplex immunoassay, whilesFlt-1 was assessed using ELISA. sEGFR was significantly lower in preterm preeclampsia than matched control (p < 0.001) and mildly lower in term preeclampsia than matched control (p < 0.01). On contrary, sFlt-1 was significantly higher in preterm preeclampsia than matched control (p < 0.001) and mildly higher in term preeclampsia than matched control (p < 0.01). sFlt-1, sFlt-1/sEGFR and sFlt-1/PLGF were positively correlated with the severity of preterm preeclampsia (P < 0.001, R value ≥ 0.6), especially sFlt-1/sEGFR had the highest R value (R value = 0.711) among them. Furthermore, sEndoglin and the ratio of sEndoglin/sEGFR were associated with neonatal birth weight small for gestational age (SGA, n = 25) in preterm preeclampsia group.

CONCLUSIONS

The ratio of sFlt-1/sEGFR could be used as a novel candidate biochemical marker in monitoring the severity of preterm preeclampsia. sEndoglin and sEGFR may be involved in the pathogenesis of SGA in preterm preelampsia.

Oxidative Stress in Preeclampsia and Placental Diseases

Preeclampsia is a persistent hypertensive gestational disease characterized by high blood pressure and proteinuria, which presents from the second trimester of pregnancy. At the cellular level, preeclampsia has largely been associated with the release of free radicals by the placenta. Placenta-borne oxidative and nitrosative stresses are even sometimes considered as the major molecular determinants of the maternal disease. In this review, we present the recent literature evaluating free radical production in both normal and pathological placentas (including preeclampsia and other major pregnancy diseases), in humans and animal models. We then assess the putative effects of these free radicals on the placenta and maternal endothelium. This analysis was conducted with regard to recent papers and possible therapeutic avenues.

Oxidative stress in placental pathology

The most important function of the placenta is the exchange of nutrients and oxygen between a mother and her fetus. To establish a healthy functioning placenta, placentation needs to occur with adequate remodelling of spiral arteries by extravillous trophoblasts. When this process is impaired, the resulting suboptimal and inadequate placenta function results in the manifestation of pregnancy complications. Impaired placenta function can cause preeclampsia and leads to fetal growth restriction due to hypoxia. Presence of hypoxia leads to oxidative stress due to an imbalance between reactive oxygen species and antioxidants, thereby causing damage to proteins, lipids and DNA. In the placenta, signs of morphological adaptation in response to hypoxia can be found. Different placental lesions like maternal or fetal vascular malperfusion or chronic villitis lead to a decreased exchange of oxygen between the mother and the fetus. Clinically, several biomarkers indicative for oxidative stress, e.g. malondialdehyde and reduced levels of free thiols are found. This review aims to give an overview of the causes and (potential) role of placental oxidative stress in the development of placental parenchymal pathology and its clinical consequences. Also, therapeutic options aiming at prevention or treatment of hypoxia of the placenta and fetus are described.

Serum protein marker panel for predicting preeclampsia

BACKGROUND

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSIONS

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

Timing of probiotic milk consumption during pregnancy and effects on the incidence of preeclampsia and preterm delivery: a prospective observational cohort study in Norway

OBJECTIVES

To investigate whether the timing of probiotic milk intake before, during early or late pregnancy influences associations with preeclampsia and preterm delivery.

DESIGN

Population based prospective cohort study.

SETTING

Norway, between 1999 and 2008.

PARTICIPANTS

70 149 singleton pregnancies resulting in live-born babies from the Norwegian Mother and Child Cohort Study (no chronic disease, answered questionnaires, no placenta previa/cerclage/serious malformation of fetus, first enrolment pregnancy). Only nulliparous women (n=37 050) were included in the preeclampsia analysis. Both iatrogenic and spontaneous preterm delivery (between gestational weeks 22+0 and 36+6) with spontaneous term controls (between gestational weeks 39+0 and 40+6) were included in the preterm delivery analysis resulting in 34 458 cases.

MAIN OUTCOME MEASURES

Adjusted OR for preeclampsia and preterm delivery according to consumption of probiotic milk at three different time periods (before pregnancy, during early and late pregnancy).

RESULTS

Probiotic milk intake in late pregnancy (but not before or in early pregnancy) was significantly associated with lower preeclampsia risk (adjusted OR: 0.80 (95% CI 0.68 to 0.94) p-value: 0.007). Probiotic intake during early (but not before or during late pregnancy) was significantly associated with lower risk of preterm delivery (adjusted OR: 0.79 (0.64 to 0.97) p-value: 0.03).

CONCLUSIONS

In this observational study, we found an association between timing of probiotic milk consumption during pregnancy and the incidence of the adverse pregnancy outcomes preeclampsia and preterm delivery. If future randomised controlled trials could establish a causal association between probiotics consumption and reduced risk of preeclampsia and preterm delivery, recommending probiotics would be a promising public health measure to reduce these adverse pregnancy outcomes.

Augmented H2S production via cystathionine-beta-synthase upregulation plays a role in pregnancy-associated uterine vasodilation

Endogenous hydrogen sulfide (H2S) synthesized via metabolizing L-cysteine by cystathionine-beta-synthase (CBS) and cystathionine-gamma-lyase (CSE) is a potent vasodilator and angiogenic factor. The objectives of this study were to determine if human uterine artery (UA) H2S production increases with augmented expression and/or activity of CBS and/or CSE during the menstrual cycle and pregnancy and whether exogenous H2S dilates UA. Uterine arteries from nonpregnant (NP) premenopausal proliferative (pPRM) and secretory (sPRM) phases of the menstrual cycle and pregnant (P) women were studied. H2S production was measured by the methylene blue assay. CBS and CSE mRNAs were assessed by quantitative real-time PCR, and proteins were assessed by immunoblotting and semiquantitative immunofluorescence microscopy. Effects of H2S on rat UA relaxation were determined by wire myography ex vivo. H2S production was greater in NP pPRM and P than NP sPRM UAs and inhibited by the specific CBS but not CSE inhibitor. CBS but not CSE mRNA and protein were greater in NP pPRM and P than NP sPRM UAs. CBS protein was localized to endothelium and smooth muscle and its levels were in a quantitative order of P >NP UAs of pPRM>sPRM. CSE protein was localized in UA endothelium and smooth muscle with no difference among groups. A H2S donor relaxed P > NP UAs but not mesentery artery. Thus, human UA H2S production is augmented with endothelium and smooth muscle CBS upregulation, contributing to UA vasodilation in the estrogen-dominant physiological states in the proliferative phase of the menstrual cycle and pregnancy.

The Mediterranean diet adherence by pregnant women delivering prematurely: association with size at birth and complications of prematurity

Background: The Mediterranean diet (MD) is associated with decreased risk of metabolic syndrome and gestational diabetes due to the anti-inflammatory and antioxidative properties of its components. The aim was to investigate the potential association of MD adherence (MDA) during pregnancy by mothers delivering prematurely, with intrauterine growth as expressed by neonates' anthropometry at birth and complications of prematurity. Participants and methods: This is a single-center, prospective, observational cohort study of 82 women who delivered preterm singletons at post conceptional age (PCA) ≤ 34 weeks and their live-born neonates. Maternal and neonatal demographic and clinical data were recorded. All mothers filled in a food frequency questionnaire, and the MDA score was calculated. Based on 50th centile of MD score, participants were classified into high-MDA and low-MDA groups. Results: The low-MDA mothers had significantly higher pregestational BMI and rates of overweight/obesity (odd ratios (OR) 3.5) and gestational hypertension/preeclampsia (OR 3.8). Neonates in the low-MDA group had significantly higher incidence of intrauterine growth restriction (IUGR) (OR 3.3) and lower z-scores of birth weight and BMI. Regarding prematurity-related complications, the low MDA-group was more likely to develop necrotizing enterocolitis, bronchopulmonary dysplasia, and retinopathy of prematurity (OR 3.2, 1.3, and 1.6, respectively), while they were less likely to develop respiratory distress syndrome (OR 0.49), although the differences were not statistically significant. However, adjustment for confounders revealed MDA as a significant independent predictor of hypertension/preeclampsia, IUGR, birth weight z-score, necrotizing enterocolitis, and bronchopulmonary dysplasia. Conclusions: High MDA during pregnancy may favorably affect intrauterine growth and certain acute and chronic complications of prematurity as well as maternal hypertension/preeclampsia.

Impact of particle size and surface modification on gold nanoparticle penetration into human placental microtissues

Aim: Nanoparticle-based drug carriers hold great promise for the development of targeted therapies in pregnancy with reduced off-target effects. Here, we performed a mechanistic in vitro study on placental localization and penetration of gold nanoparticles (AuNPs) in dependence of particle size and surface modification. Materials & methods: AuNP uptake and penetration in human placental coculture microtissues was assessed by inductively coupled plasma-mass spectrometry, transmission electron microscopy and laser ablation-inductively coupled plasma-mass spectrometry. Results: Higher uptake and deeper penetration was observed for smaller (3–4 nm) or sodium carboxylate-modified AuNPs than for larger (13–14 nm) or PEGylate AuNPs, which barely passed the trophoblast barrier layer. Conclusion: It is possible to steer placental uptake and penetration of AuNPs by tailoring their properties, which is a prerequisite for the development of targeted therapies in pregnancy.

Maternal Metabolism and Vascular Adaptation in Pregnancy: The PPAR Link

Current therapies for pregnancy-related hypertension and its complications remain inadequate, although an increasing role for maternal susceptibility is becoming evident. Systemic vascular dysfunction in response to imbalances in angiogenic, inflammatory, and constricting factors is implicated in the pathogenesis of gestational hypertension, and growing evidence now links these factors with maternal metabolism. In particular, the crucial role of peroxisome proliferator-activated receptors (PPARs) in maternal vascular adaptation provides further insights into how obesity and gestational diabetes may be linked to pregnancy-induced hypertension and preeclampsia. This is especially important given the rapidly growing prevalence of obesity during pregnancy, and highlights a new approach to treat pregnancy-related hypertension and its complications.

Molecular hydrogen ameliorates several characteristics of preeclampsia in the Reduced Uterine Perfusion Pressure (RUPP) rat model

Oxidative stress plays an important role in the pathogenesis of preeclampsia. Recently, molecular hydrogen (H₂) has been shown to have therapeutic potential in various oxidative stress-related diseases. The aim of this study is to investigate the effect of H₂ on preeclampsia. We used the reduced utero-placental perfusion pressure (RUPP) rat model, which has been widely used as a model of preeclampsia. H₂ water (HW) was administered orally ad libitum in RUPP rats from gestational day (GD) 12-19, starting 2 days before RUPP procedure. On GD19, mean arterial pressure (MAP) was measured, and samples were collected. Maternal administration of HW significantly decreased MAP, and increased fetal and placental weight in RUPP rats. The increased levels of soluble fms-like tyrosine kinase-1 (sFlt-1) and diacron reactive oxygen metabolites as a biomarker of reactive oxygen species in maternal blood were decreased by HW administration. However, vascular endothelial growth factor level in maternal blood was increased by HW administration. Proteinuria, and histological findings in kidney were improved by HW administration. In addition, the effects of H₂ on placental villi were examined by using a trophoblast cell line (BeWo) and villous explants from the placental tissue of women with or without preeclampsia. H₂ significantly attenuated hydrogen peroxide-induced sFlt-1 expression, but could not reduce the expression induced by hypoxia in BeWo cells. H₂ significantly attenuated sFlt-1 expression in villous explants from women with preeclampsia, but not affected them from normotensive pregnancy. The prophylactic administration of H₂ attenuated placental ischemia-induced hypertension, angiogenic imbalance, and oxidative stress. These results support the theory that H₂ has a potential benefit in the prevention of preeclampsia.

Alpha-1 Antitrypsin Prevents the Development of Preeclampsia Through Suppression of Oxidative Stress

Preeclampsia (PE) and its complications have become the leading cause of maternal and fetal morbidity and mortality in the world. And the development of PE is still barely predictable and thus challenging to prevent and manage clinically. Oxidative stress contributes to the development of the disease. Our previous study demonstrated that exogenous Alpha-1 antitrypsin (AAT) played a cytoprotective role in vascular endothelial cell by suppressing oxidative stress. In this study, we aim to investigate whether AAT contributes to the development of PE, and to identify the mechanism behind these effects. We found that AAT levels were significantly decreased in placenta tissues from women with PE compared that of healthy women. Notably, we demonstrate that AAT injection is able to relieve the high blood pressure and reduce urine protein levels in a dose-dependent manner in PE mice. In addition, our results showed that AAT injection exhibited an anti-oxidative stress role by significantly reducing PE mediated-upregulation of ROS, MMP9 and MDA, and increasing the levels of SOD, eNOS, and GPx with increased dosage of AAT. Furthermore, we found that AAT injection inactivated PE mediated activation of PAK/STAT1/p38 signaling. These findings were confirmed in human samples. In conclusion, our study suggests that exogenous AAT injection increases the antioxidants and suppresses oxidative stress, and subsequent prevention of PE development through inactivation of STAT1/p38 signaling. Thus, AAT would become a potential strategy for PE therapy.

A Dormant Microbial Component in the Development of Preeclampsia

Preeclampsia (PE) is a complex, multisystem disorder that remains a leading cause of morbidity and mortality in pregnancy. Four main classes of dysregulation accompany PE and are widely considered to contribute to its severity. These are abnormal trophoblast invasion of the placenta, anti-angiogenic responses, oxidative stress, and inflammation. What is lacking, however, is an explanation of how these themselves are caused. We here develop the unifying idea, and the considerable evidence for it, that the originating cause of PE (and of the four classes of dysregulation) is, in fact, microbial infection, that most such microbes are dormant and hence resist detection by conventional (replication-dependent) microbiology, and that by occasional resuscitation and growth it is they that are responsible for all the observable sequelae, including the continuing, chronic inflammation. In particular, bacterial products such as lipopolysaccharide (LPS), also known as endotoxin, are well known as highly inflammagenic and stimulate an innate (and possibly trained) immune response that exacerbates the inflammation further. The known need of microbes for free iron can explain the iron dysregulation that accompanies PE. We describe the main routes of infection (gut, oral, and urinary tract infection) and the regularly observed presence of microbes in placental and other tissues in PE. Every known proteomic biomarker of "preeclampsia" that we assessed has, in fact, also been shown to be raised in response to infection. An infectious component to PE fulfills the Bradford Hill criteria for ascribing a disease to an environmental cause and suggests a number of treatments, some of which have, in fact, been shown to be successful. PE was classically referred to as endotoxemia or toxemia of pregnancy, and it is ironic that it seems that LPS and other microbial endotoxins really are involved. Overall, the recognition of an infectious component in the etiology of PE mirrors that for ulcers and other diseases that were previously considered to lack one.

Complement Activation in Placental Malaria

Sixty percent of all pregnancies worldwide occur in malaria endemic regions. Pregnant women are at greater risk of malaria infection than their non-pregnant counterparts and have a higher risk of adverse birth outcomes including low birth weight resulting from intrauterine growth restriction and/or preterm birth. The complement system plays an essential role in placental and fetal development as well as the host innate immune response to malaria infection. Excessive or dysregulated complement activation has been associated with the pathobiology of severe malaria and with poor pregnancy outcomes, dependent and independent of infection. Here we review the role of complement in malaria and pregnancy and discuss its part in mediating altered placental angiogenesis, malaria-induced adverse birth outcomes, and disruptions to the in utero environment with possible consequences on fetal neurodevelopment. A detailed understanding of the mechanisms underlying adverse birth outcomes, and the impact of maternal malaria infection on fetal neurodevelopment, may lead to biomarkers to identify at-risk pregnancies and novel therapeutic interventions to prevent these complications.

Pharmacological models and approaches for pathophysiological conditions associated with hypoxia and oxidative stress

Hypoxia is the failure of oxygenation at the tissue level, where the reduced oxygen delivered is not enough to satisfy tissue demands. Metabolic depression is the physiological adaptation associated with reduced oxygen consumption, which evidently does not cause any harm to organs that are exposed to acute and short hypoxic insults. Oxidative stress (OS) refers to the imbalance between the generation of reactive oxygen species (ROS) and the ability of endogenous antioxidant systems to scavenge ROS, where ROS overwhelms the antioxidant capacity. Oxidative stress plays a crucial role in the pathogenesis of diseases related to hypoxia during intrauterine development and postnatal life. Thus, excessive ROS are implicated in the irreversible damage to cell membranes, DNA, and other cellular structures by oxidizing lipids, proteins, and nucleic acids. Here, we describe several pathophysiological conditions and in vivo and ex vivo models developed for the study of hypoxic and oxidative stress injury. We reviewed existing literature on the responses to hypoxia and oxidative stress of the cardiovascular, renal, reproductive, and central nervous systems, and discussed paradigms of chronic and intermittent hypobaric hypoxia. This systematic review is a critical analysis of the advantages in the application of some experimental strategies and their contributions leading to novel pharmacological therapies.

Brain endoplasmic reticulum stress mechanistically distinguishes the saline-intake and hypertensive response to deoxycorticosterone acetate-salt

Endoplasmic reticulum stress has become an important mechanism in hypertension. We examined the role of endoplasmic reticulum stress in mediating the increased saline-intake and hypertensive effects in response to deoxycorticosterone acetate (DOCA)-salt. Intracerebroventricular delivery of the endoplasmic reticulum stress-reducing chemical chaperone tauroursodeoxycholic acid did not affect the magnitude of hypertension, but markedly decreased saline-intake in response to DOCA-salt. Increased saline-intake returned after tauroursodeoxycholic acid was terminated. Decreased saline-intake was also observed after intracerebroventricular infusion of 4-phenylbutyrate, another chemical chaperone. Immunoreactivity to CCAAT homologous binding protein, a marker of irremediable endoplasmic reticulum stress, was increased in the subfornical organ and supraoptic nucleus of DOCA-salt mice, but the signal was absent in control and CCAAT homologous binding protein-deficient mice. Electron microscopy revealed abnormalities in endoplasmic reticulum structure (decrease in membrane length, swollen membranes, and decreased ribosome numbers) in the subfornical organ consistent with endoplasmic reticulum stress. Subfornical organ-targeted adenoviral delivery of GRP78, a resident endoplasmic reticulum chaperone, decreased DOCA-salt-induced saline-intake. The increase in saline-intake in response to DOCA-salt was blunted in CCAAT homologous binding protein-deficient mice, but these mice exhibited a normal hypertensive response. We conclude that (1) brain endoplasmic reticulum stress mediates the saline-intake, but not blood pressure response to DOCA-salt, (2) DOCA-salt causes endoplasmic reticulum stress in the subfornical organ, which when attenuated by GRP78 blunts saline-intake, and (3) CCAAT homologous binding protein may play a functional role in DOCA-salt-induced saline-intake. The results suggest a mechanistic distinction between the importance of endoplasmic reticulum stress in mediating effects of DOCA-salt on saline-intake and blood pressure.

Oxidative stress in preeclampsia and the role of free fetal hemoglobin

Preeclampsia is a leading cause of pregnancy complications and affects 3-7% of pregnant women. This review summarizes the current knowledge of a new potential etiology of the disease, with a special focus on hemoglobin-induced oxidative stress. Furthermore, we also suggest hemoglobin as a potential target for therapy. Gene and protein profiling studies have shown increased expression and accumulation of free fetal hemoglobin in the preeclamptic placenta. Predominantly due to oxidative damage to the placental barrier, fetal hemoglobin leaks over to the maternal circulation. Free hemoglobin and its metabolites are toxic in several ways; (a) ferrous hemoglobin (Fe(2+)) binds strongly to the vasodilator nitric oxide (NO) and reduces the availability of free NO, which results in vasoconstriction, (b) hemoglobin (Fe(2+)) with bound oxygen spontaneously generates free oxygen radicals, and (c) the heme groups create an inflammatory response by inducing activation of neutrophils and cytokine production. The endogenous protein α1-microglobulin, with radical and heme binding properties, has shown both ex vivo and in vivo to have the ability to counteract free hemoglobin-induced placental and kidney damage. Oxidative stress in general, and more specifically fetal hemoglobin-induced oxidative stress, could play a key role in the pathology of preeclampsia seen both in the placenta and ultimately in the maternal endothelium.