Asymmetric dimethylarginine levels in preeclampsia - Systematic review and meta-analysis

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.

Extracellular Vesicles Derived from Human Umbilical Cord MSC Improve Vascular Endothelial Function in In Vitro and In Vivo Models of Preeclampsia through Activating Arginine Metabolism

Endothelial cell damage is an important feature of preeclampsia (PE). Human umbilical mesenchymal stem-cell-derived extracellular vesicles (HUMSCs-derived EVs) have been shown to have therapeutic effects on a variety of diseases and tissue damage. However, the therapeutic effect of HUMSCs-derived EVs on endothelial injury in PE remains unclear. This study explored the possible mechanism of HUMSCs-derived EVs in the treatment of endothelial cell injury. Tumor necrosis factor α- and lipopolysaccharide-induced endothelial dysfunction models were used to evaluate the therapeutic effect of HUMSCs-derived EVs on endothelial injury. We further constructed PE mouse models to explore the function of HUMSCs-derived EVs in vivo. The changes of metabolites in endothelial cells after HUMSCs-derived EVs treatment were analyzed by metabolomics analysis and further validated by cell experiments. HUMSCs-derived EVs treatment can alleviate endothelial cell injury in PE, involving cell proliferation, migration, angiogenesis, and anti-inflammatory. Importantly, administration of HUMSCs-derived EVs improves hypertension and proteinuria in PE mice, alleviates kidney damage, and promotes vascularization in the placenta. Furthermore, metabolomics analysis found that the arginine metabolic pathway is activated after HUMSCs-derived EVs treatment. We also observed increased arginine level, nitric oxide content, and nitric oxide synthase activity, and further experiments proved that activating the arginine metabolic pathway could alleviate endothelial dysfunction. Our results reveal that HUMSCs-derived EVs could ameliorate PE endothelial dysfunction by activating the arginine metabolic pathway and may serve as a therapeutic method for treating PE.

Early prediction of pre-eclampsia using circulating placental exosomes: Newer insights

Pre-eclampsia (PE), a multifactorial de novo hypertensive pregnancy disorder, is one of the leading causes of foeto-maternal morbidity and mortality. Currently, antihypertensive drugs are the first-line therapy for PE and evidence suggests that low-dose aspirin initiated early in high risk pregnancies may reduce the risk of development or severity of PE. However, an early prediction of this disorder remains an unmet clinical challenge. Several potential serum biomarkers associated with maternal immunoregulation and placental angiogenesis have been evaluated but are ineffective and inconsistent for early prediction. Although placental biomarkers would be more specific and sensitive in predicting the risk of PE, accessing the placenta during pregnancy is not feasible. Circulating placental exosomes (pEXO), originating from foeto-maternal interface, are being evaluated as the placenta's surrogate and the best source of non-invasive placental biomarkers. pEXO appear in the maternal circulation starting from six weeks of gestation and its dynamic biological cargo across pregnancy is associated with successful pregnancy outcomes. Therefore, monitoring changes in pEXO expression profiles could provide new insights into the prediction, diagnosis and treatment of PE. This narrative review comprehensively summarizes the available literature on the candidate predictive circulating biomarkers evaluated for PE to date. In particular, the review elucidates the current knowledge of distinct molecular signatures emanating from pEXO in pre-eclamptic women to support the discovery of novel early predictive biomarkers for effective intervention and management of the disease.

Advances in preeclampsia testing

Preeclampsia is a multisystem hypertensive disorder and one of the leading causes of maternal and fetal morbidity and mortality. The clinical hallmarks such as hypertension and proteinuria, and additional laboratory tests currently available including liver enzyme testing, are neither specific nor sufficiently sensitive. Therefore, biomarkers for timely and accurate identification of patients at risk of developing preeclampsia are extremely valuable to improve patient outcomes and safety. In this chapter, we will first discuss the clinical characteristics of preeclampsia and current evidence of the role of angiogenic factors, such as placental growth factor (PlGF) and soluble FMS like tyrosine kinase 1 (sFlt-1) in the pathogenesis of preeclampsia. Second, we will review the clinical practice guidelines for preeclampsia diagnostic criteria and their recommendations on laboratory testing. Third, we will review the currently available PlGF and sFlt-1 assays in terms of their methodologies, analytical performance, and clinical diagnostic values. Finally, we will discuss the future research needs from both an analytical and clinical perspective.

New Ideas for the Prevention and Treatment of Preeclampsia and Their Molecular Inspirations

Preeclampsia (PE) is a pregnancy-specific disorder affecting 4-10% of all expectant women. It greatly increases the risk of maternal and foetal death. Although the main symptoms generally appear after week 20 of gestation, scientific studies indicate that the mechanism underpinning PE is initiated at the beginning of gestation. It is known that the pathomechanism of preeclampsia is strongly related to inflammation and oxidative stress, which influence placentation and provoke endothelial dysfunction in the mother. However, as of yet, no "key players" regulating all these processes have been discovered. This might be why current therapeutic strategies intended for prevention or treatment are not fully effective, and the only effective method to stop the disease is the premature induction of delivery, mostly by caesarean section. Therefore, there is a need for further research into new pharmacological strategies for the treatment and prevention of preeclampsia. This review presents new preventive methods and therapies for PE not yet recommended by obstetrical and gynaecological societies. As many of these therapies are in preclinical studies or under evaluation in clinical trials, this paper reports the molecular targets of the tested agents or methods.

Diagnostic biomolecules and combination therapy for pre-eclampsia

Pre-eclampsia (PE), associated with placental malperfusion, is the primary reason for maternal and perinatal mortality and morbidity that can cause vascular endothelial injury and multi-organ injury. Despite considerable research efforts, no pharmaceutical has been shown to stop disease progression. If women precisely diagnosed with PE can achieve treatment at early gestation, the maternal and fetal outcomes can be maximally optimized by expectant management. Current diagnostic approaches applying maternal characteristics or biophysical markers, including blood test, urine analysis and biophysical profile, possess limitations in the precise diagnosis of PE. Biochemical factor research associated with PE development has generated ambitious diagnostic targets based on PE pathogenesis and dissecting molecular phenotypes. This review focuses on current developments in biochemical prediction of PE and the corresponding interventions to ameliorate disease progression, aiming to provide references for clinical diagnoses and treatments.

Evaluation of the predictive values of elevated serum L-homoarginine and dimethylarginines in preeclampsia

L-homoarginine (hARG) is involved in nitric oxide biosynthesis, but its role and concentration in preeclampsia (PE) have not been fully revealed. The purpose of this study was to develop and validate a feasible clinical assay to quantify serum hARG, arginine (ARG), asymmetric (ADMA) and symmetric dimethylarginines (SDMA) levels by LC-MS/MS and investigate their differences at different stages of pregnancy with or without preeclampsia. Serum samples were collected from 84 pregnant women without complications (controls), 84 with mild preeclampsia (MPE), and 81 with severe preeclampsia (SPE) at various gestation stages (before the 20th week, during the 20th-28th week or after the 28th week of gestation). No significant difference in ARG levels was observed between PE and controls at any stage (P > 0.05). The serum hARG levels and hARG/ADMA ratios of MPE before the 20th week were higher than those of controls (P < 0.001). ADMA levels of MPE were higher than those of controls during the 20th-28th week (P < 0.01). SDMA levels of SPE were higher than those of MPE (P < 0.01) and controls (P < 0.05) after the 28th week. Elevated serum hARG before the 20th week was identified as an independent predictor for PE (OR = 1.478, 95% CI 1.120-1.950). ROC curve analysis showed serum hARG before the 20th week had a good potential to predict MPE (AUC = 0.875, 95% CI 0.759-0.948). In conclusion, our study indicated that elevated serum hARG and dimethylarginine levels detected by LC-MS/MS might serve as potential biomarkers for the early prediction of PE.

Clinical tools and biomarkers to predict preeclampsia

Preeclampsia is pregnancy-specific, and significantly contributes to maternal, and perinatal morbidity and mortality worldwide. An effective predictive test for preeclampsia would facilitate early diagnosis, targeted surveillance and timely delivery; however limited options currently exist. A first-trimester screening algorithm has been developed and validated to predict preterm preeclampsia, with poor utility for term disease, where the greatest burden lies. Biomarkers such as sFlt-1 and placental growth factor are also now being used clinically in cases of suspected preterm preeclampsia; their high negative predictive value enables confident exclusion of disease in women with normal results, but sensitivity is modest. There has been a concerted effort to identify potential novel biomarkers that might improve prediction. These largely originate from organs involved in preeclampsia's pathogenesis, including placental, cardiovascular and urinary biomarkers. This review outlines the clinical imperative for an effective test and those already in use and summarises current preeclampsia biomarker research.

Longitudinal Changes of One-Carbon Metabolites and Amino Acid Concentrations during Pregnancy in the Women First Maternal Nutrition Trial

BACKGROUND

Maternal dietary restriction and supplementation of one-carbon (1C) metabolites can impact offspring growth and DNA methylation. However, longitudinal research of 1C metabolite and amino acid (AA) concentrations over the reproductive cycle of human pregnancy is limited.

OBJECTIVE

To investigate longitudinal 1C metabolite and AA concentrations prior to and during pregnancy and the effects of a small-quantity lipid-based nutrition supplement (LNS) containing >20 micronutrients and prepregnancy BMI (ppBMI).

METHODS

This study was an ancillary study of the Women First Trial (NCT01883193, clinicaltrials.gov) focused on a subset of Guatemalan women (n = 134), 49% of whom entered pregnancy with a BMI ≥25 kg/m2. Ninety-five women received LNS during pregnancy (+LNS group), while the remainder did not (-LNS group). A subset of women from the Pakistan study site (n = 179) were used as a replication cohort, 124 of whom received LNS. Maternal blood was longitudinally collected on dried blood spot (DBS) cards at preconception, and at 12 and 34 wk gestation. A targeted metabolomics assay was performed on DBS samples at each time point using LC-MS/MS. Longitudinal analyses were performed using linear mixed modeling to investigate the influence of time, LNS, and ppBMI.

RESULTS

Concentrations of 23 of 27 metabolites, including betaine, choline, and serine, changed from preconception across gestation after application of a Bonferroni multiple testing correction (P < 0.00185). Sixteen of those metabolites showed similar changes in the replication cohort. Asymmetric and symmetric dimethylarginine were decreased by LNS in the participants from Guatemala. Only tyrosine was statistically associated with ppBMI at both study sites.

CONCLUSIONS

Time influenced most 1C metabolite and AA concentrations with a high degree of similarity between the 2 diverse study populations. These patterns were not significantly altered by LNS consumption or ppBMI. Future investigations will focus on 1C metabolite changes associated with infant outcomes, including DNA methylation. This trial was registered at clinicaltrials.gov as NCT01883193.

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.

Use of Nutraceuticals in Angiogenesis-Dependent Disorders

The term of angiogenesis refers to the growth of new vessels from pre-existing capillaries. The phenomenon is necessary for physiological growth, repair and functioning of our organs. When occurring in a not regulated manner, it concurs to pathological conditions as tumors, eye diseases, chronic degenerative disorders. On the contrary insufficient neovascularization or endothelial disfunction accompanies ischemic and metabolic disorders. In both the cases an inflammatory and oxidative condition exists in supporting angiogenesis deregulation and endothelial dysfunction. The use of nutraceuticals with antioxidant and anti-inflammatory activities can be a therapeutic option to maintain an adequate vascularization and endothelial cell proper functioning or to blunt aberrant angiogenesis. A revision of the updated literature reports on nutraceuticals to guide endothelial cell wellness and to restore physiological tissue vascularization is the objective of this paper. The critical aspects as well as lacking data for human use will be explored from a pharmacological perspective.