Differential expression of miRNAs are associated with the insulin signaling pathway in preeclampsia and gestational hypertension

Expression analysis of microRNAs and cytokine mRNAs in pregnancies complicated by gestational hypertension

OBJECTIVES

Gestational hypertension (GH1) is one of the most common pregnancy-related complications, however, there is still insufficient knowledge about its development and molecular changes. The aim of our study was to examine the expression of miR-17, miR-29a and miR-181a, as well as TNF-α, IL-1β, IL-6 and IL-17 in women with GH and to investigate possible correlations between these parameters.

STUDY DESIGN

The study included 64 pregnant women, placed either in the control or the GH group. Quantitative real-time PCR (qPCR2) was used to determine expression levels of microRNAs and cytokines' mRNAs.

MAIN OUTCOME MEASURES

Expression levels of miRNAs (miR-17, miR-29a and miR-181a) and proinflammatory cytokines mRNAs (TNF-α, IL-1β, IL-6 and IL-17) in women with gestational hypertension were compared to the control group (healthy pregnant women).

RESULTS

No significant changes in microRNAs expression level were found between compared groups. TNF-α was significantly upregulated in the GH group compared to controls. Expression levels of other investigated cytokines did not differ between examined groups. ROC curve analysis indicated that TNF-α does not show sufficient ability to discriminate between CG and GH patients. TNF-α was significantly positively correlated with IL-1β and IL-17 and negatively correlated with miR-181a.

CONCLUSIONS

Our results point to the involvement of proinflamatory cytokines in gestational hypertension. Although increased expression of TNF-α was found in the GH group, this cytokine did not show sufficient ability to discriminate between GH and healthy pregnancies.

Circulating miRNAs and Preeclampsia: From Implantation to Epigenetics

In this review, we comprehensively present the literature on circulating microRNAs (miRNAs) associated with preeclampsia, a pregnancy-specific disease considered the primary reason for maternal and fetal mortality and morbidity. miRNAs are single-stranded non-coding RNAs, 20-24 nt long, which control mRNA expression. Changes in miRNA expression can induce a variation in the relative mRNA level and influence cellular homeostasis, and the strong presence of miRNAs in all body fluids has made them useful biomarkers of several diseases. Preeclampsia is a multifactorial disease, but the etiopathogenesis remains unclear. The functions of trophoblasts, including differentiation, proliferation, migration, invasion and apoptosis, are essential for a successful pregnancy. During the early stages of placental development, trophoblasts are strictly regulated by several molecular pathways; however, an imbalance in these molecular pathways can lead to severe placental lesions and pregnancy complications. We then discuss the role of miRNAs in trophoblast invasion and in the pathogenesis, diagnosis and prediction of preeclampsia. We also discuss the potential role of miRNAs from an epigenetic perspective with possible future therapeutic implications.

The role and expression of pro/antiangiogenic factors and microRNAs in gestational hypertension and pre-eclampsia

OBJECTIVE

Pre-eclampsia and gestational hypertension are two common hypertensive disorders of pregnancy with pre-eclampsia accounting for high foetal and maternal morbidity and mortality rate. These disorders have an unknown aetiology and their hypertensive and end-organ pathophysiology may present too late in pregnancy. This makes the identification of early detection and differentiation markers vital. MicroRNAs have strongly been associated with pregnancy and their imbalance has been associated with the angiogenic dysregulation seen in pre-eclampsia. This study assesses the expression of pro- and antiangiogenic factors and their corresponding microRNAs in the maternal circulation of patients with pre-eclampsia and gestational hypertension.

STUDY DESIGN

We analyzed angiogenic factors expression (sEng, TGF-β, VEGF) normalized against housekeeping gene β-actin and microRNAs (miRs: 210, 29B, 126) normalized against miR U6, potentially associated with pre-eclampsia and gestational hypertension using the targeted qPCR technique. These analytes were examined from early-onset (<34 weeks) (EOPE) (n = 12), late-onset (>34 weeks) (LOPE) (n = 12) pre-eclampsia, gestational hypertension (GH) (n = 12) and two gestationally matched normotensive groups (NG1 and 2) (n = 12) each in South African women of African ancestry. Group comparisons of experimental vs. control groups were assessed using t-test analysis for significance and represented as fold change expression.

RESULTS

The relative expression in group comparisons showed significant (p < 0.05) fold change of VEGF, TGF-β, sEng and miR126 in the EOPE vs. NG1. The GH vs. NG1 exhibited significant changes in VEGF, TGF-β, miR126, miR210 and miR29B. The LOPE vs. NG2 showed significant relative expression in all the angiogenic factors (VEGF, TGF-β and sEng). The GH vs. NG2 showed significant expression in VEGF and miR29B. The LOPE vs. EOPE showed significant fold changes in VEGF and miR210. Finally, only the GH vs. EOPE showed significant differences in miR210 and miR29B (p < 0.05).

CONCLUSION

This study provides better insights into angiogenic factors and microRNAs specificity to the subtypes of gestational hypertensive disorders in pregnancy. Relative expression analysis of angiogenic factors and microRNAs showed possible novel characteristics of gestational hypertension, and potential common molecular and pathological profiles with pre-eclampsia. Furthermore, we postulate that sEng and miR29B could be early detection markers for pre-eclampsia and gestational hypertension, respectively.

The Role of Placental Non-Coding RNAs in Adverse Pregnancy Outcomes

Non-coding RNAs (ncRNAs) are transcribed from the genome and do not encode proteins. In recent years, ncRNAs have attracted increasing attention as critical participants in gene regulation and disease pathogenesis. Different categories of ncRNAs, which mainly include microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), are involved in the progression of pregnancy, while abnormal expression of placental ncRNAs impacts the onset and development of adverse pregnancy outcomes (APOs). Therefore, we reviewed the current status of research on placental ncRNAs and APOs to further understand the regulatory mechanisms of placental ncRNAs, which provides a new perspective for treating and preventing related diseases.

An Investigation of Exosome Concentration and Exosomal microRNA (miR-155 and miR-222) Expression in Pregnant Women with Gestational Hypertension and Preeclampsia

Introduction

Hypertensive disorders of pregnancy are characterized by widespread maternal endothelial dysfunction. Elevated secretion of exosomes has been associated with endothelial dysfunction. Exosomes play a role in cell-cell communication by transferring microRNAs. These microRNAs are associated with the pathogenesis of hypertensive disorders of pregnancy through the regulation of endothelial function. This study characterizes exosomes and determines exosomal miR-155 and miR-222 expression levels in women with gestational hypertension (GH) and preeclampsia (PE).

Methods

Exosomes were isolated and thereafter characterised using NTA, microscopy and ELISA. Results: Exosomes were elevated in the serum of pregnant women with GH and PE (P<0.05). The circulating exosomes and placental exosomes were increased in both GH and PE (P<0.0001). The exosomal miR-155 increased in PE but not in GH (P < 0.05). MiR-222 decreased in PE (P < 0.05).

Discussion

Elevated exosomes in pregnant women with GH and PE may be indicative of exosomes being potential biomarkers for both GH and PE. The difference in the exosomal miR-155 and miR-222 expression in PE and GH suggested that these two disorders have different pathological pathways.

Comparison of the Chemical Components, Efficacy and Mechanisms of Action of Chrysanthemum morifolium Flower and Its Wild Relative Chrysanthemum indicum Flower against Liver-Fire Hyperactivity Syndrome of Hypertension via Integrative Analyses

To clarify the differences in the clinical application scope of Chrysanthemum morifolium flower (CMF) and Chrysanthemum indicum flower (CIF), two herbs of similar origin, an integrated strategy of network pharmacology, molecular pharmacology, and metabolomics was employed, with a view to investigating the commonalities and dissimilarities in chemical components, efficacy and mechanisms of action. Initial HPLC-Q-TOF-MS analysis revealed that CMF and CIF had different flavonoid constituents. The biological processes underlying the therapeutic effects of CMF and CIF on liver-fire hyperactivity syndrome of hypertension (LFHSH) were predicted to be related to inflammatory response, fatty acid production, and other pathways based on network pharmacology analysis. ELISA, molecular docking, Western blot, and metabolomics techniques showed similar effects of CMF and CIF in lowering blood pressure, resistance to tissue, organ and functional damage, and dyslipidemia. However, distinct effects were found in the regulation of inflammatory response, PI3K-Akt and NF-κB signaling pathways, lipid anabolism, renin-angiotensin system, and metabolic abnormalities. The comparable efficacies of CMF and CIF, despite having distinct mechanisms of action, may be attributed to the integration and counteraction of their different regulating capabilities on the above anti-LFHSH mechanisms. This study offers a vital platform for assessment of differential and precise applications of herbs of close origin with similar but slightly different medicinal properties, and provides a research strategy for bridging Chinese medicine and modern precision medicine.

Combinatorial Analysis of Circulating Biomarkers and Maternal Characteristics for Preeclampsia Prediction in the First and Third Trimesters in Asia

We aim to establish a prediction model for pregnancy outcomes through a combinatorial analysis of circulating biomarkers and maternal characteristics to effectively identify pregnant women with higher risks of preeclampsia in the first and third trimesters within the Asian population. A total of two hundred and twelve pregnant women were screened for preeclampsia through a multicenter study conducted in four recruiting centers in Taiwan from 2017 to 2020. In addition, serum levels of sFlt-1/PlGF ratio, miR-181a, miR-210 and miR-223 were measured and transformed into multiples of the median. We thus further developed statistically validated algorithmic models by designing combinations of different maternal characteristics and biomarker levels. Through the performance of the training cohort (0.848 AUC, 0.73−0.96 95% CI, 80% sensitivity, 85% specificity, p < 0.001) and the validation cohort (0.852 AUC, 0.74−0.98 95% CI, 75% sensitivity, 87% specificity, p < 0.001) from one hundred and fifty-two women with a combination of miR-210, miR-181a and BMI, we established a preeclampsia prediction model for the first trimester. We successfully identified pregnant women with higher risks of preeclampsia in the first and third trimesters in the Asian population using the established prediction models that utilized combinatorial analysis of circulating biomarkers and maternal characteristics.

The Relationship between Angiogenic Factors and Energy Metabolism in Preeclampsia

Antiangiogenic factors are currently used for the prediction of preeclampsia. The present study aimed to evaluate the relationship between antiangiogenic factors and lipid and carbohydrate metabolism in maternal plasma and placenta. We analyzed 56 pregnant women, 30 healthy and 26 with preeclampsia (including early and late onset). We compared antiangiogenic factors soluble Fms-like Tyrosine Kinase-1 (sfLt-1), placental growth factor (PlGF), and soluble endoglin (sEng)), lipid and carbohydrate metabolism in maternal plasma, and lipid metabolism in the placenta from assays of fatty acid oxidation, fatty acid esterification, and triglyceride levels in all groups. Antiangiogenic factors sFlt-1, sFlt-1/PlGF ratio, and sEng showed a positive correlation with triglyceride, free fatty acid, and C-peptide maternal serum levels. However, there was no relationship between angiogenic factors and placental lipid metabolism parameters. Free fatty acids were predictive of elevated sFlt-1 and sEng, while C-peptide was predictive of an elevated sFlt1/PlGF ratio. The findings in this study generate a model to predict elevated antiangiogenic factor values and the relationship between them with different products of lipid and carbohydrate metabolism in maternal serum and placenta in preeclampsia.

Preeclamptic Women Have Disrupted Placental microRNA Expression at the Time of Preeclampsia Diagnosis: Meta-Analysis

Introduction: Preeclampsia (PE) is a pregnancy-associated, multi-organ, life-threatening disease that appears after the 20th week of gestation. The aim of this study was to perform a systematic review and meta-analysis to determine whether women with PE have disrupted miRNA expression compared to women who do not have PE. Methods: We conducted a systematic review and meta-analysis of studies that reported miRNAs expression levels in placenta or peripheral blood of pregnant women with vs. without PE. Studies published before October 29, 2021 were identified through PubMed, EMBASE and Web of Science. Two reviewers used predefined forms and protocols to evaluate independently the eligibility of studies based on titles and abstracts and to perform full-text screening, data abstraction and quality assessment. Standardized mean difference (SMD) was used as a measure of effect size. Results: 229 publications were included in the systematic review and 53 in the meta-analysis. The expression levels in placenta were significantly higher in women with PE compared to women without PE for miRNA-16 (SMD = 1.51,95%CI = 0.55-2.46), miRNA-20b (SMD = 0.89, 95%CI = 0.33-1.45), miRNA-23a (SMD = 2.02, 95%CI = 1.25-2.78), miRNA-29b (SMD = 1.37, 95%CI = 0.36-2.37), miRNA-155 (SMD = 2.99, 95%CI = 0.83-5.14) and miRNA-210 (SMD = 1.63, 95%CI = 0.69-2.58), and significantly lower for miRNA-376c (SMD = -4.86, 95%CI = -9.51 to -0.20). An increased level of miRNK-155 expression was found in peripheral blood of women with PE (SMD = 2.06, 95%CI = 0.35-3.76), while the expression level of miRNA-16 was significantly lower in peripheral blood of PE women (SMD = -0.47, 95%CI = -0.91 to -0.03). The functional roles of the presented miRNAs include control of trophoblast proliferation, migration, invasion, apoptosis, differentiation, cellular metabolism and angiogenesis. Conclusion: miRNAs play an important role in the pathophysiology of PE. The identification of differentially expressed miRNAs in maternal blood creates an opportunity to define an easily accessible biomarker of PE.

The Predictive Value of miR-16, -29a and -134 for Early Identification of Gestational Diabetes: A Nested Analysis of the DALI Cohort

Early identification of gestational diabetes mellitus (GDM) aims to reduce the risk of adverse maternal and perinatal outcomes. Currently, no circulating biomarker has proven clinically useful for accurate prediction of GDM. In this study, we tested if a panel of small non-coding circulating RNAs could improve early prediction of GDM. We performed a nested case-control study of participants from the European multicenter ‘Vitamin D and lifestyle intervention for GDM prevention (DALI)’ trial using serum samples from obese pregnant women (BMI ≥ 29 kg/m²) entailing 82 GDM cases (early- and late- GDM), and 41 age- and BMI-matched women with normal glucose tolerance (NGT) throughout pregnancy (controls). Anthropometric, clinical and biochemical characteristics were obtained at baseline (<20 weeks of gestation) and throughout gestation. Baseline serum microRNAs (miRNAs) were measured using quantitative real time PCR (qPCR). Elevated miR-16-5p, -29a-3p, and -134-5p levels were observed in women, who were NGT at baseline and later developed GDM, compared with controls who remained NGT. A combination of the three miRNAs could distinguish later GDM from NGT cases (AUC 0.717, p = 0.001, compared with fasting plasma glucose (AUC 0.687, p = 0.004)) as evaluated by area under the curves (AUCs) using Receiver Operator Characteristics (ROC) analysis. Elevated levels of individual miRNAs or a combination hereof were associated with higher odds ratios of GDM. Conclusively, circulating miRNAs early in pregnancy could serve as valuable predictive biomarkers of GDM.

NFKB1-mediated downregulation of microRNA-106a promotes oxidative stress injury and insulin resistance in mice with gestational hypertension

This study intended to investigate the role of NFKB1 in oxidative stress injury and insulin resistance in gestational hypertension (GH) mice. Following establishment of a GH mouse model by high-fat diet, NFKB1, miR-106a, and FLOT2 expression was detected in liver of mice. After NFKB1, miR-106a, and FLOT2 were altered in GH mice by lentiviral vector, oxidative stress markers in liver tissues were examined by colorimetry, and insulin resistance was assessed by fasting blood glucose and fasting insulin levels. Next, hepatocytes were isolated from GH mice and treated with miR-106a mimic, inhibitor or siRNA, followed by determination of hepatocyte apoptosis and the expression of inflammation- and apoptosis-related factors. Evaluation of the correlations among NFKB1, miR-106a, and FLOT2 were conducted. Liver of GH mice harbored NFKB1 and FLOT2 upregulation and miR-106a downregulation. miR-106a was transcriptionally inhibited by NFKB1, and negatively targeted FLOT2. Oxidative stress injury and insulin resistance in GH mice and apoptosis and inflammation of hepatocytes from GH mice were decreased after silencing NFKB1 or FLOT2 or overexpressing miR-106a. These findings provided evidence demonstrating the inhibitory effect of NFKB1 silencing on oxidative stress injury and insulin resistance in GH mice via miR-106a upregulation and FLOT2 downregulation.

Preeclampsia-Associated lncRNA INHBA-AS1 Regulates the Proliferation, Invasion, and Migration of Placental Trophoblast Cells

Preeclampsia is believed to be caused by impaired placentation with insufficient trophoblast invasion, leading to impaired uterine spiral artery remodeling and angiogenesis. However, the underlying molecular mechanism remains unknown. We recently carried out transcriptome profiling of placental long noncoding RNAs (lncRNAs) and identified 383 differentially expressed lncRNAs in early-onset severe preeclampsia. Here, we are reporting our identification of lncRNA INHBA-AS1 as a potential causal factor of preeclampsia and its downstream pathways that may be involved in placentation. We found that INHBA-AS1 was upregulated in patients and positively correlated with clinical severity. We systematically searched for potential INHBA-AS1-binding transcription factors and their targets in databases and found that the targets were enriched with differentially expressed genes in the placentae of patients. We further demonstrated that the lncRNA INHBA-AS1 inhibited the invasion and migration of trophoblast cells through restraining the transcription factor CENPB from binding to the promoter of TNF receptor-associated factor 1 (TRAF1). Therefore, we have identified the dysregulated pathway "INHBA-AS1-CENPB-TRAF1" as a contributor to the pathogenesis of preeclampsia through prohibiting the proliferation, invasion, and migration of trophoblasts during placentation.

Association of lncRNA SH3PXD2A-AS1 with preeclampsia and its function in invasion and migration of placental trophoblast cells

Accumulating evidence suggests that the pathogenesis of preeclampsia involves poor placentation caused by insufficient trophoblast invasion and impaired uterine spiral artery remodeling, yet the underlying molecular mechanism remains unclear. We carried out transcriptome profiling on placentae from preeclamptic patients and normal subjects, and identified about four hundred long non-coding RNAs differentially expressed in placentae of patients with early-onset severe preeclampsia. Here, we report our identification of lncRNA SH3PXD2A-AS1 as a potential causal factor for this disease and its downstream pathways involved in placentation. We found that expression level of SH3PXD2A-AS1 in the placentae is positively correlated with clinical severity of the patients. We demonstrated that SH3PXD2A-AS1 inhibited invasion and migration through recruiting CCCTC-binding factor (CTCF) to the promoters of SH3PXD2A and CCR7 to inhibit their transcription. Therefore, we conclude that the upregulation of lncRNA SH3PXD2A-AS1 may contribute to the pathogenesis of preeclampsia through prohibiting trophoblast invasion during placentation.

From animal models to patients: the role of placental microRNAs, miR-210, miR-126, and miR-148a/152 in preeclampsia

Placental microRNAs (miRNAs) regulate the placental transcriptome and play a pathological role in preeclampsia (PE), a hypertensive disorder of pregnancy. Three PE rodent model studies explored the role of placental miRNAs, miR-210, miR-126, and miR-148/152 respectively, by examining expression of the miRNAs, their inducers, and potential gene targets. This review evaluates the role of miR-210, miR-126, and miR-148/152 in PE by comparing findings from the three rodent model studies with in vitro studies, other animal models, and preeclamptic patients to provide comprehensive insight into genetic components and pathological processes in the placenta contributing to PE. The majority of studies demonstrate miR-210 is upregulated in PE in part driven by HIF-1α and NF-κBp50, stimulated by hypoxia and/or immune-mediated processes. Elevated miR-210 may contribute to PE via inhibiting anti-inflammatory Th2-cytokines. Studies report an up- and downregulation of miR-126, arguably reflecting differences in expression between cell types and its multifunctional capacity. MiR-126 may play a pro-angiogenic role by mediating the PI3K-Akt pathway. Most studies report miR-148/152 family members are upregulated in PE. Evidence suggests they may inhibit DNA methylation of genes involved in metabolic and inflammatory pathways. Given the genetic heterogeneity of PE, it is unlikely that a single placental miRNA is a suitable therapeutic target for all patients. Investigating miRNAs in PE subtypes in patients and animal models may represent a more appropriate approach going forward. Developing methods for targeting placental miRNAs and specific placental cell types remains crucial for research seeking to target placental miRNAs as a novel treatment for PE.

Pregnancy-associated cardiac dysfunction and the regulatory role of microRNAs

Many crucial cardiovascular adaptations occur in the body during pregnancy to ensure successful gestation. Maladaptation of the cardiovascular system during pregnancy can lead to complications that promote cardiac dysfunction and may lead to heart failure (HF). About 12% of pregnancy-related deaths in the USA have been attributed to HF and the detrimental effects of cardiovascular complications on the heart can be long-lasting, pre-disposing the mother to HF later in life. Indeed, cardiovascular complications such as gestational diabetes mellitus, preeclampsia, gestational hypertension, and peripartum cardiomyopathy have been shown to induce cardiac metabolic dysfunction, oxidative stress, fibrosis, apoptosis, and diastolic and systolic dysfunction in the hearts of pregnant women, all of which are hallmarks of HF. The exact etiology and cardiac pathophysiology of pregnancy-related complications is not yet fully deciphered. Furthermore, diagnosis of cardiac dysfunction in pregnancy is often made only after clinical symptoms are already present, thus necessitating the need for novel diagnostic and prognostic biomarkers. Mounting data demonstrates an altered expression of maternal circulating miRNAs during pregnancy affected by cardiovascular complications. Throughout the past decade, miRNAs have become of growing interest as modulators and biomarkers of pathophysiology, diagnosis, and prognosis in cardiac dysfunction. While the association between pregnancy-related cardiovascular complications and cardiac dysfunction or HF is becoming increasingly evident, the roles of miRNA-mediated regulation herein remain poorly understood. Therefore, this review will summarize current reports on pregnancy-related cardiovascular complications that may lead to cardiac dysfunction and HF during and after pregnancy in previously healthy women, with a focus on the pathophysiological role of miRNAs.

The role of epigenetic changes in preeclampsia

Preeclampsia (PE) is a disorder affecting 2-10% of pregnancies and has a major role for perinatal and maternal mortality and morbidity. PE can be occurred by initiation of new hypertension combined with proteinuria after 20 weeks gestation, as well as various reasons such as inflammatory cytokines, poor trophoblast invasion can be related with PE disease. Environmental factors can cause epigenetic changes including DNA methylation, microRNAs (miRNAs), and histone modification that may be related to different diseases such as PE. Abnormal DNA methylation during placentation is the most important epigenetic factor correlated with PE. Moreover, changes in histone modification like acetylation and also the effect of overregulation or low regulation of miRNAs or long noncoding RNAs on variety signaling pathways can be resulted in PE. The aim of this review is to describe of studies about epigenetic changes in PE and its therapeutic strategies.

Angiogenesis, Lymphangiogenesis, and the Immune Response in South African Preeclamptic Women Receiving HAART

Purpose of the review: This review highlights the role of angiogenesis, lymphangiogenesis, and immune markers in human immunodeficiency virus (HIV)-associated preeclamptic (PE) pregnancies in an attempt to unravel the mysteries underlying the duality of both conditions in South Africa. Recent findings: Studies demonstrate that HIV-infected pregnant women develop PE at a lower frequency than uninfected women. In contrast, women receiving highly active anti-retroviral therapy (HAART) are more inclined to develop PE, stemming from an imbalance of angiogenesis, lymphangiogenesis, and immune response. Summary: In view of the paradoxical effect of HIV infection on PE development, this study examines angiogenesis, lymphangiogenesis, and immune markers in the highly HIV endemic area of KwaZulu-Natal. We believe that HAART re-constitutes the immune response in PE, thereby predisposing women to PE development. This susceptibility is due to an imbalance in the angiogenic/lymphangiogenic/immune response as compared to normotensive pregnant women. Further large-scale studies are urgently required to investigate the effect of the duration of HAART on PE development.

Epigenetic modification: a regulatory mechanism in essential hypertension

Essential hypertension (EH) is a multifactorial disease of the cardiovascular system that is influenced by the interplay of genetic, epigenetic, and environmental factors. The molecular dynamics underlying EH etiopathogenesis is unknown; however, earlier studies have revealed EH-associated genetic variants. Nevertheless, this finding alone is not sufficient to explain the variability in blood pressure, suggesting that other risk factors are involved, such as epigenetic modifications. Therefore, this review highlights the potential contribution of well-defined epigenetic mechanisms in EH, specifically, DNA methylation, post-translational histone modifications, and microRNAs. We further emphasize global and gene-specific DNA methylation as one of the most well-studied hallmarks among all epigenetic modifications in EH. In addition, post-translational histone modifications, such as methylation, acetylation, and phosphorylation, are described as important epigenetic markers associated with EH. Finally, we discuss microRNAs that affect blood pressure by regulating master genes such as those implicated in the renin-angiotensin-aldosterone system. These epigenetic modifications, which appear to contribute to various cardiovascular diseases, including EH, may be a promising research area for the development of novel future strategies for EH prevention and therapeutics.