Assessment of l-arginine asymmetric 1 dimethyl (ADMA) in early-onset and late-onset (severe) preeclampsia

Early and late-onset preeclampsia: effects of DDAH2 polymorphisms on ADMA levels and association with DDAH2 haplotypes

Objective

To examine whether the DDAH2 promoter polymorphisms -1415G/A (rs2272592), -1151A/C (rs805304) and -449G/C (rs805305), and their haplotypes, are associated with PE compared with normotensive pregnant women, and whether they affect ADMA levels in these groups.

Methods

A total of 208 pregnant women were included in the study and classified as early-onset (N=57) or late-onset PE (N =49), and as normotensive pregnant women (N = 102).

Results

Pregnant with early-onset PE carrying the GC and GG genotypes for the DDAH2 -449G/C polymorphism had increased ADMA levels (P=0.01). No association of DDAH2 polymorphisms with PE in single-locus analysis was found. However, the G-C-G haplotype was associated with the risk for late-onset PE.

Conclusion

It is suggested that DDAH2 polymorphisms could affect ADMA levels in PE, and that DDAH2 haplotypes may affect the risk for PE.

Evaluation of oxidative stress markers in subtypes of preeclampsia: A systematic review and meta-analysis

Studies about oxidative stress biomarkers revealed different phenotypes between early and late preeclampsia (PE). Despite that, there is extensive evidence of oxidative stress in investigations that combinate forms different of preeclampsia. This study reviews the oxidative stress profile in the PE subtypes and evaluates which markers are altered in the blood and placental tissue. A search was conducted in databases such as MEDLINE, EMBASE, LILACS, and Web of Science without restricting the year and language of publication. The quality of the studies was evaluated by the Newcastle-Ottawa scale and Joanna Briggs Institute for analytical Cross-Sectional Studies. After 13,319 screened records, 65 were included in the systematic review. The markers of stress oxidative of damage and reactive species were those selected, such as malondialdehyde (MDA), lipid peroxide, advanced protein oxidation products, carbonyl protein, 8-hydroxy-2'-deoxyguanosine, total oxidant status, hydrogen peroxide, nitric oxide (NO). We described the antioxidant activity, including the superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase, free glutathione, and total antioxidant capacity (TAC). We results demonstrated that oxidative stress is related to pathophysiology of PE, there were increased lipid peroxidation in the blood and placenta, and in blood a reduction of NO levels and of TAC, like lower enzymatic activity of GPx, CAT in PE, and SOD in mild PE. In addition, altered levels of MDA in the placenta and blood show that placental changes have repercussions on the clinical syndrome and are related to the severity of the disease.

Decreased nitric oxide content mediated by asymmetrical dimethylarginine and protein l-arginine methyltransferase 3 in macrophages induces trophoblast apoptosis: a potential cause of recurrent miscarriage

STUDY QUESTION

Is the protein l-arginine methyltransferase 3 (PRMT3)/asymmetrical dimethylarginine (ADMA)/nitric oxide (NO) pathway involved in the development of recurrent miscarriage (RM), and what is the potential mechanism?

SUMMARY ANSWER

Elevated levels of PRMT3 and ADMA inhibit NO formation in the decidua, thereby impairing the functions of trophoblast cells at the maternal-foetal interface.

WHAT IS KNOWN ALREADY

Decreased NO bioavailability is associated with RM. ADMA, an endogenous inhibitor of nitric oxide synthase (NOS), is derived from the methylation of protein arginine residues by PRMTs and serves as a predictor of mortality in critical illness.

STUDY DESIGN, SIZE, DURATION

A total of 145 women with RM and 149 healthy women undergoing elective termination of an early normal pregnancy were enrolled. Ninety-six female CBA/J, 24 male DBA/2 and 24 male BALB/c mice were included. CBA/J × DBA/2 matings represent the abortion group, while CBA/J × BALB/c matings represent the normal control group. The CBA/J pregnant mice were then categorised into four groups: (i) normal + vehicle group (n = 28), (ii) abortion + vehicle group (n = 28), (iii) normal + SGC707 (a PRMT3 inhibitor) group (n = 20) and (iv) abortion + SGC707 group (n = 20). All injections were made intraperitoneally on Days 0.5, 3.5 and 6.5 of pregnancy. Decidual tissues were collected on Days 8.5, 9.5 and 10.5 of gestation. The embryo resorption rates were calculated on Day 9.5 and Day 10.5 of gestation.

PARTICIPANTS/MATERIALS, SETTING, METHODS

NO concentration, ADMA content, NOS activity, expression levels of NOS and PRMTs in decidual tissues were determined using conventional assay kits or western blotting. PRMT3 expression was further analysed in decidual stromal cells, macrophages and natural killer cells. A co-culture system between decidual macrophages (DMs) and HTR-8/SVneo trophoblasts was constructed to study the roles of the PRMT3/ADMA/NO signalling pathway. Trophoblast apoptosis was analysed via Annexin V-fluorescein isothiocyanate/propidium iodide staining. CBA/J × DBA/2 mouse models were used to investigate the effects of SGC707 on embryo resorption rates.

MAIN RESULTS AND THE ROLE OF CHANCE

Our results show that NO concentration and NOS activity were decreased, but ADMA content and PRMT3 expression were increased in the decidua of RM patients. Moreover, compared with the normal control subjects, PRMT3 expression was significantly up-regulated in the macrophages but not in the natural killer cells or stromal cells of the decidua from RM patients. The inhibition of PRMT3 results in a significant decrease in ADMA accumulation and an increase in NO concentration in macrophages. When co-cultured with DMs, which were treated with SGC707 and ADMA, trophoblast apoptosis was suppressed and induced, respectively. In vivo experiments revealed that the administration of SGC707 reduced the embryo resorption rate of CBA/J × DBA/2 mice.

LIMITATIONS, REASONS FOR CAUTION

All sets of experiments were not performed with the same samples. The main reason is that each tissue needs to be reserved for clinical diagnosis and only a small piece of each tissue can be cut and collected for this study.

WIDER IMPLICATIONS OF THE FINDINGS

Our results indicate that the PRMT3/ADMA/NO pathway is a potential marker and target for the clinical diagnosis and therapy of RM.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the National Key Research and Development Program of China (2017YFC1001401), National Natural Science Foundation of China (81730039, 82071653, 81671460, 81971384 and 82171657) and Shanghai Municipal Medical and Health Discipline Construction Projects (2017ZZ02015). The authors have declared no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Endothelial dysfunction biomarkers in sickle cell disease: is there a role for ADMA and PAI-1?

Within the spectrum of sickle cell disease (SCD) are sickle cell anemia (SCA), presence of hemoglobin SS (HbSS), hemoglobin SC disease (HbSC), and sickle cell β-thalassemia (Sβ-thal). Asymmetric dimethylarginine (ADMA) competitively inhibits the binding of arginine to NOS, reducing NO production. In patients with HbSS, increased levels of ADMA have been reported, as well as changes in many hemostatic biomarkers, including the plasminogen activator inhibitor type 1 (PAI-1). We hypothesized that high levels of ADMA and PAI-1 may be associated with more severe SCD. Thus, ADMA and PAI-1 levels were determined in 78 individuals including 38 adult patients with SCD and 40 control subjects. Higher levels of ADMA were shown in HbSS and Sβ-thal patients compared to controls. Concerning PAI-1, all patients showed high levels of PAI-1 compared to controls. As a role of NO in the pathogenesis of SCD has already been established, we concluded that high levels of ADMA should compromise, at least in part, NO synthesis, resulting in endothelial dysfunction. Elevated plasma levels of PAI-1 in all patients may indicate not only endothelial dysfunction but also a hypofibrinolytic state favoring thrombotic complications. Finally, high levels of ADMA and PAI-1 may be associated with more severe SCD.

Activation of arginase II by asymmetric dimethylarginine and homocysteine in hypertensive rats induced by hypoxia: a new model of nitric oxide synthesis regulation in hypertensive processes?

In recent years, the increase in blood pressure at high altitudes has become an interesting topic among high-altitude researchers. In our animal studies using Wistar rats, we observed the existence of two rat populations that exhibit differential physiological responses during hypoxic exposure. These rats were classified as hypoxia-induced hypertensive rats and nonhypertensive rats. A decrease in nitric oxide levels was reported in different hypertension models associated with increased concentrations of asymmetric dimethylarginine (ADMA) and homocysteine, and we recently described an increase in arginase type II expression under hypoxia. ADMA and homocysteine decrease nitric oxide (NO) bioavailability; however, whether ADMA and homocysteine have a regulatory effect on arginase activity and therefore regulate another NO synthesis pathway is unknown. Therefore, the aim of this study was to measure basal ADMA and homocysteine levels in hypoxia-induced hypertensive rats and evaluate their effect on arginase II activity. Our results indicate that hypoxia-induced hypertensive rats presented lower nitric oxide concentrations than nonhypertensive rats, associated with higher concentrations of homocysteine and ADMA. Hypoxia-induced hypertensive rats also presented lower dimethylarginine dimethylaminohydrolase-2 and cystathionine β-synthase levels, which could explain the high ADMA and homocysteine levels. In addition, we observed that both homocysteine and ADMA had a significant effect on arginase II activation in the hypertensive rats. Therefore, we suggest that ADMA and homocysteine have dual regulatory effects on NO synthesis. The former has an inhibitory effect on eNOS, and the latter has a secondary activating effect on arginase II. We propose that arginase II is activated by AMDA and homocysteine in hypoxia-induced hypertensive rats.

Maternal serum levels of asymmetric dimethylarginine in normal and preeclamptic pregnancies

The study aims to investigate maternal serum levels of asymmetric dimethylarginine (ADMA) in preeclampsia. Serum samples were collected from 57 women with preeclamptic pregnancies and 30 women with normal pregnancies during the third trimester. ADMA levels were measured with the ELISA method. ADMA levels in preeclamptic pregnancies were significantly higher when compared with normal pregnancies (2.35 ± 3.20 nmol/l versus 0.35 ± 0.10 nmol/l; p < .05). ADMA levels show a significant positive correlation with systolic and diastolic pressure, urea, and creatinine but a negative correlation with proteinuria. ADMA levels have a significant strong correlation with PE. ADMA levels are significantly higher in preeclamptic pregnancy compared with normal pregnancy.

Utility of time of onset of hypertension, ADMA and TAS in predicting adverse neonatal outcome in hypertensive disorders of pregnancy

Background: Limited studies have been conducted to evaluate the utility of indices for the prediction of the adverse neonatal outcomes in hypertensive disorders of pregnancy (HDP).Method: A total of 174 pregnant women with HDP (gestational hypertension, late onset preeclampsia, and early onset preeclampsia) and 49 controls were sampled during the third trimester. Preterm birth, low birth weight, fetal, and infant mortality and low Apgar scores were assessed.Results: Multivariate analysis confirmed systolic blood pressure (SBP), time of onset of hypertension (TOH), and total antioxidant status (TAS) as predictors of preterm births; TOH and diastolic blood pressure (DBP) to be predictors of low birth weight babies; TOH and asymmetric dimethyl arginine (ADMA) as predictors of fetal mortality and babies with low Apgar at 5 min. We found TOH as the single best predictor for adverse neonatal outcomes.Conclusion: This study identified TOH as an important predictor of most of the adverse neonatal outcomes.

Adipokines and Endothelium Dysfunction Markers in Pregnant Women with Gestational Hypertension

Objective

The aim of the study was to evaluate the levels of adipokines such as adiponectin and leptin as well as soluble intercellular adhesion molecule-1 (sICAM-1) and endogenous NOS inhibitor-asymmetric dimethylarginine (ADMA), as the endothelium dysfunction markers in pregnant women with gestational hypertension (GH).

Patients and Methods

Adiponectin, leptin, sICAM-1, and ADMA concentrations were measured in a group of 34 patients with GH and in 32 healthy pregnant women between the 24^th and 34^th week of gestation with ELISA tests.

Results

The patients with GH compared with healthy ones were characterized by significantly higher BMI (28.09 ± 7.90 vs. 22.34 ± 4.21 kg/m², p=0.016) and higher concentrations of leptin (45.89 ± 35.91 vs. 24.09 ± 24.40 ng/mL, p=0.006). sICAM-1 levels were also higher in the GH group but without the statistical significance (264.51 ± 50.99 vs. 232.56 ± 43.3 ng/ml, p=0.057). There were no significant differences between groups in adiponectin (8.79 ± 8.67 vs. 7.90 ± 3.71 μg/mL, p=0.46, NS) and ADMA (0.57 ± 0.26 vs. 0.60 ± 0.24 μmol/L, p=0.68, NS) levels. The significant correlation between leptin levels and BMI value was observed only in patients with GH (R = 0.56, p=0.02).

Conclusions

The higher levels of leptin in pregnant women with gestational hypertension may be suggestive of the role of leptin in GH development. As the patients in the GH group had higher BMI, hyperleptinemia may link obesity with gestational hypertension. The significance of leptin as the predictive marker of GH development could be implied. It could be postulated that the higher levels of sICAM-1 in the GH patients, although not statistically significant, could reflect some impairment of the endothelium function occurring in GH regardless of BMI. The comparable adiponectin levels in GH and healthy pregnant patients and the lack of its correlation with BMI may indicate the occurrence of a protective mechanism in pregnancy maintaining its concentration and preserving from the consequences of the decrease in its levels in overweight and obese patients. Since ADMA levels were similar in GH and healthy pregnant women, ADMA seems not to be involved in GH pathogenesis, suggesting that NO synthesis is not impaired in this pregnancy complication. As the data on the gestational hypertension pathogenesis and its correlations with adipokines and markers of the endothelium dysfunction are limited, further studies on this issue are warranted.

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 Role of Nitric Oxide, ADMA, and Homocysteine in The Etiopathogenesis of Preeclampsia-Review

Preeclampsia is a serious, pregnancy-specific, multi-organ disease process of compound aetiology. It affects 3–6% of expecting mothers worldwide and it persists as a leading cause of maternal and foetal morbidity and mortality. In fact, hallmark features of preeclampsia (PE) result from vessel involvement and demonstrate maternal endothelium as a target tissue. Growing evidence suggests that chronic placental hypoperfusion triggers the production and release of certain agents that are responsible for endothelial activation and injury. In this review, we will present the latest findings on the role of nitric oxide, asymmetric dimethylarginine (ADMA), and homocysteine in the etiopathogenesis of preeclampsia and their possible clinical implications.

Altered methylation and expression patterns of genes regulating placental nitric oxide pathway in patients with severe preeclampsia

Pre-eclampsia is a common pregnancy disorder syndrome whose molecular mechanism is not clear. Nitric oxide (NO) is a key regulator of placentation. Reduction of NO has previously been associated with endothelial dysfunction in pre-eclamptic women. Therefore, we measured expression and methylation of some placental genes that were involved in NO pathway like named ARG II, PRMT1 and DDAH2 in pre-eclampsia and normal pregnancies in order to determine whether impairment of expression of these genes in the pre-eclamptic placenta could contribute to development of disease. ARG II, PRMT1 expressions as well as DDAH2 expression and methylation, in placentas collected from 59 patients with preeclampsia and 40 normotensive pregnancies were measured using real-time PCR and methylation specific PCR, respectively. The relationship among ARG II, PRMT1 and DDAH2 expressions was analyzed statistically. ARG II expression was increased, PRMT1 expression was not significantly changed. DDAH2 expression was decreased and qualitative methylation patterns were 32/59 and 21/40 in placentas from patients with pre-eclampsia compared with control group, respectively. The alterations in ARG II and DDAH2 expressions in pre-eclampsia patients maybe correlated with decreased eNOS expression. These findings indicate that ARG II and DDAH2 may be involved in pre-eclampsia pathogenesis and could be potential therapeutic targets for this disease.

Resolution of inflammation pathways in preeclampsia-a narrative review

Preeclampsia (PE) is one of the leading causes of maternal morbidity and mortality worldwide. This disease is believed to occur in two stages with placental dysfunction in early pregnancy leading to maternal clinical findings after 20 weeks of gestation, as consequence of systemic inflammation, oxidative stress, and endothelial dysfunction. Much evidence suggests that PE women display an overshooting inflammatory response throughout pregnancy due to an unbalanced regulation of innate and adaptive immune responses. Recently, it has been suggested that dysregulation of endogenous protective pathways might be associated with PE etiopathogenesis. Resolution of inflammation is an active process coordinated by mediators from diverse nature that regulate key cellular events to restore tissue homeostasis. Inadequate or insufficient resolution of inflammation is believed to play an important role in the development of chronic inflammatory diseases, like PE. In this narrative review, we discuss possible pro-resolution pathways that might be compromised in PE women, which could be targets to novel therapeutic strategies in this disease.

New Models of Pregnancy-Associated Hypertension

Pregnancy-associated hypertensive disorders are leading causes of maternal and fetal mortality. These include: pre-pregnancy hypertension that persists throughout gestation (chronic/preexisting hypertension), de novo hypertension that is diagnosed after 20 weeks of gestation and resolves after birth (gestational hypertension), de novo hypertension that is diagnosed after 20 weeks of gestation with or without proteinuria and end-organ damage (preeclampsia and eclampsia), and chronic hypertension with superimposed preeclampsia during gestation. Preeclampsia is the most severe form of these disorders. Animal models have been developed by employing surgical, genetic, and pharmacological approaches in order to recapitulate the maternal symptoms of preeclampsia and other hypertensive disorders of pregnancy. The scope of this brief review is to present an up-to-date synthesis of our knowledge of experimental models of pregnancy-associated hypertensive disorders. Novel models, defined in this review as characterized within the last 5 years, will be described and critically discussed. In this review, we will also discuss established experimental models of pregnancy-associated hypertensive disorders in the context of their contribution to new advances in our knowledge about the pathophysiology of these disorders and potential therapeutics. Emphasis will be placed on animal models of preeclampsia; however, models of other hypertensive disorders in pregnancy will also be reviewed.

Altered Endothelial Nitric Oxide Signaling as a Paradigm for Maternal Vascular Maladaptation in Preeclampsia

PURPOSE OF REVIEW

The goal of this review is to present the newest insights into what we view as a central failure of cardiovascular adaptation in preeclampsia (PE) by focusing on one clinically significant manifestation of maternal endothelial dysfunction: nitric oxide signaling. The etiology, symptoms, and current theories of the PE syndrome are described first, followed by a review of the available evidence, and underlying causes of reduced endothelial nitric oxide (NO) signaling in PE.

RECENT FINDINGS

PE maladaptations include, but are not limited to, altered physiological stimulatory inputs (e.g., estrogen; VEGF/PlGF; shear stress) and substrates (L-Arg; ADMA), augmented placental secretion of anti-angiogenic and inflammatory factors such as sFlt-1 and Eng, changes in eNOS (polymorphisms, expression), and reduced bioavailability of NO secondary to oxidative stress. PE is a complex obstetrical syndrome that is associated with maternal vascular dysfunction. Diminished peripheral endothelial vasodilator influence in general, and of NO signaling specifically, are key in driving disease progression and severity.

Inhibitors of the Hydrolytic Enzyme Dimethylarginine Dimethylaminohydrolase (DDAH): Discovery, Synthesis and Development

Dimethylarginine dimethylaminohydrolase (DDAH) is a highly conserved hydrolytic enzyme found in numerous species, including bacteria, rodents, and humans. In humans, the DDAH-1 isoform is known to metabolize endogenous asymmetric dimethylarginine (ADMA) and monomethyl arginine (l-NMMA), with ADMA proposed to be a putative marker of cardiovascular disease. Current literature reports identify the DDAH family of enzymes as a potential therapeutic target in the regulation of nitric oxide (NO) production, mediated via its biochemical interaction with the nitric oxide synthase (NOS) family of enzymes. Increased DDAH expression and NO production have been linked to multiple pathological conditions, specifically, cancer, neurodegenerative disorders, and septic shock. As such, the discovery, chemical synthesis, and development of DDAH inhibitors as potential drug candidates represent a growing field of interest. This review article summarizes the current knowledge on DDAH inhibition and the derived pharmacokinetic parameters of the main DDAH inhibitors reported in the literature. Furthermore, current methods of development and chemical synthetic pathways are discussed.

Intercellular Adhesion Molecule and Endogenous NOS Inhibitor: Asymmetric Dimethylarginine in Pregnant Women with Gestational Diabetes Mellitus

OBJECTIVE

The aim of the study was to evaluate the concentrations of soluble intercellular adhesion molecule-1 (s-ICAM-1) and endogenous NOS inhibitor, asymmetric dimethylarginine (ADMA), as markers of endothelium dysfunction in patients with gestational diabetes mellitus (GDM).

PATIENTS AND METHODS

The levels of s-ICAM-1 and ADMA were analysed in the group of 56 patients with GDM and compared to 25 healthy pregnant women. The concentrations of s-ICAM-1 and ADMA were measured in serum using ELISA tests.

RESULTS

The groups did not differ by baseline descriptors: age (30.75 ± 6.32 versus 28.50 ± 4.95 years, NS) and gestational age (28.96 ± 2.85 versus 29.12 ± 2.96 hbd, NS). The patients with GDM were more obese (BMI 27.93 ± 7.02 versus 22.34 ± 4.21 kg/m(2), p = 0.032) and had higher concentration of C-reactive protein (6.46 ± 6.03 versus 3.18 ± 3.83 mg/L, p = 0.029). In the GDM group the level of ADMA was lower (0.38 ± 0.17 versus 0.60 ± 0.28 μmol/L, p = 0.001) and the level of s-ICAM-1 was significantly higher (289.95 ± 118.12 versus 232.56 ± 43.31 ng/mL, p = 0.036) compared to controls.

CONCLUSIONS

The pregnant women with GDM are characterized by higher concentration of s-ICAM-1 that reflects the activation and dysfunction of the endothelial cells. The decreased ADMA level in GDM patients seems to be preventive in the limitation of NO synthesis caused by the impaired insulin action and the endothelial dysfunction.

Preeclampsia: long-term consequences for vascular health

Preeclampsia (PE) is a pregnancy-specific syndrome and one of the leading causes of preterm birth, neonatal and maternal morbidity and mortality. This disease is characterized by new onset hypertension usually in the third trimester of pregnancy and is sometimes associated with proteinuria, although proteinuria is not a requirement for the diagnosis of PE. In developing countries, women have a higher risk of death due to PE than more affluent countries and one of the most frequent causes of death is high blood pressure and stroke. Although PE only affects approximately 2%-8% of pregnancies worldwide it is associated with severe complications such as eclampsia, hemorrhagic stroke, hemolysis, elevated liver enzymes and low platelets (HELLP syndrome), renal failure and pulmonary edema. Importantly, there is no "cure" for the disease except for early delivery of the baby and placenta, leaving PE a health care risk for babies born from PE moms. In addition, PE is linked to the development of cardiovascular disease and stroke in women after reproductive age, leaving PE a risk factor for long-term health in women. This review will highlight factors implicated in the pathophysiology of PE that may contribute to long-term effects in women with preeclamptic pregnancies.

Is the imbalance between pro-angiogenic and anti-angiogenic factors associated with preeclampsia?

BACKGROUND

Preeclampsia (PE) is a multisystem disease characterized by the development of hypertension and proteinuria. Although PE etiology is not fully known, the placenta seems to play a central role in the development of disease. The inadequate placentation process results in a change in angiogenic factors levels, such as vascular endothelial growth factor (VEGF), placental growth factor (PlGF), soluble form of endoglin (s-Eng) and soluble form of vascular endothelial growth factor receptor type 1 (sFlt-1).

OBJECTIVE

The aim of this review was to clarify if the imbalance between pro-angiogenic and anti-angiogenic factors is associated with PE.

CONCLUSION

It is known that inadequate placentation process is the primary mechanism suggested for PE occurrence and angiogenic factors are involved in this process. The state-of-the-art suggests that progress in grasp the imbalance of pro-angiogenic and anti-angiogenic factors is essential for the improvement of knowledge about PE. The development of prospective, longitudinal studies with serial determinations of these factors throughout pregnancy is needed to better assess the relevance of these markers for understanding the etiology, prevention, diagnosis, prognosis and treatment of this challenging disease.

Molecular mechanisms of maternal vascular dysfunction in preeclampsia

In preeclampsia, as a heterogeneous syndrome, multiple pathways have been proposed for both the causal as well as the perpetuating factors leading to maternal vascular dysfunction. Postulated mechanisms include imbalance in the bioavailability and activity of endothelium-derived contracting and relaxing factors and oxidative stress. Studies have shown that placenta-derived factors [antiangiogenic factors, microparticles (MPs), cell-free nucleic acids] are released into the maternal circulation and act on the vascular wall to modify the secretory capacity of endothelial cells and alter the responsiveness of vascular smooth muscle cells to constricting and relaxing stimuli. These molecules signal their deleterious effects on the maternal vascular wall via pathways that provide the molecular basis for novel and effective therapeutic interventions.