Impaction of factors associated with oxidative stress on the pathogenesis of gestational hypertension and preeclampsia: A Chinese patients based study

The Nitrate-Nitrite-Nitric Oxide Pathway: Potential Role in Mitigating Oxidative Stress in Hypertensive Disorders of Pregnancy

Hypertensive diseases of pregnancy (HDPs) represent a global clinical challenge, affecting 5-10% of women and leading to complications for both maternal well-being and fetal development. At the heart of these complications is endothelial dysfunction, with oxidative stress emerging as a pivotal causative factor. The reduction in nitric oxide (NO) bioavailability is a vital indicator of this dysfunction, culminating in blood pressure dysregulation. In the therapeutic context, although antihypertensive medications are commonly used, they come with inherent concerns related to maternal-fetal safety, and a percentage of women do not respond to these therapies. Therefore, alternative strategies that directly address the pathophysiology of HDPs are required. This article focuses on the potential of the nitrate-nitrite-NO pathway, abundantly present in dark leafy greens and beetroot, as an alternative approach to treating HDPs. The objective of this review is to discuss the prospective antioxidant role of nitrate. We hope our discussion paves the way for using nitrate to improve endothelial dysfunction and control oxidative stress, offering a potential therapy for managing HDPs.

Quercetin stimulates trophoblast fusion via the mitochondrial function

The fusion of mononuclear trophoblasts into multinucleate syncytiotrophoblasts is the critical event in the process of syncytialization, and its dysregulation can lead to pregnancy complications, notably hypertensive disorders of pregnancy (HDP). Oxidative stress may disrupt trophoblast syncytialization in HDP. Specifically, placentas with HDP exhibit impaired mitochondria, giving rise to the generation of reactive oxygen species (ROS) and subsequent oxidative stress. Quercetin, a bioflavonoid known for its antioxidant and anti-aging properties, has the potential to mitigate oxidative stress during trophoblast syncytialization. However, the precise mechanism underlying the action of quercetin in these processes remains to be elucidated. To explore the impact of quercetin on syncytialization, mitochondrial function, and ROS generation, cyclic AMP-stimulated BeWo cells were treated with quercetin. The expression of markers associated with cell fusion, mitochondrial function, and oxidative stress was determined using qPCR and western blotting. Additionally, morphological syncytialization and mitophagy (mitochondrial degradation) were assessed by immunofluorescence analysis. Our results revealed that quercetin increased the expression of syncytialization markers and promoted cell fusion. Furthermore, this compound also upregulated markers associated with mitophagy and mitochondrial fusion, which are corroborated by visual evidence of mitophagy through the fluorescence microscope. Cell fusion naturally stimulated ROS generation, which was attenuated by quercetin. Quercetin downregulated the expression of NRF2 and HO-1 during syncytialization, while increasing the expression of sirtuin1/3/6, which are known to play essential roles in antioxidant responses. In conclusion, quercetin effectively regulates mitochondrial function through its antioxidant properties and the suppression of ROS generation, ultimately promoting trophoblast fusion, suggesting that the flavonoid has the potential to ameliorate pregnancy-related disorder stemming from placental dysplasia.

Modulation of NRF2/KEAP1 Signaling in Preeclampsia

Placentation is a key and tightly regulated process that ensures the normal development of the placenta and fetal growth. Preeclampsia (PE) is a hypertensive pregnancy-related disorder involving about 5-8% of all pregnancies and clinically characterized by de novo maternal hypertension and proteinuria. In addition, PE pregnancies are also characterized by increased oxidative stress and inflammation. The NRF2/KEAP1 signaling pathway plays an important role in protecting cells against oxidative damage due to increased reactive oxygen species (ROS) levels. ROS activate NRF2, allowing its binding to the antioxidant response element (ARE) region present in the promoter of several antioxidant genes such as heme oxygenase, catalase, glutathione peroxidase and superoxide dismutase that neutralize ROS, protecting cells against oxidative stress damages. In this review, we analyze the current literature regarding the role of the NRF2/KEAP1 pathway in preeclamptic pregnancies, discussing the main cellular modulators of this pathway. Moreover, we also discuss the main natural and synthetic compounds that can regulate this pathway in in vivo and in vitro models.

Upregulation of exofacial peroxiredoxin-thioredoxin system of lymphocytes and monocytes in preeclampsia

OBJECTIVES

An imbalanced redox homeostasis resulting in oxidative stress is present in preeclampsia. Peroxiredoxin-1 (PRDX1) and thioredoxin-1 (TRX1) regulatory enzymes are also contributing to the redox homeostasis, but were not investigated so far in preeclampsia. Thus, we have aimed to characterize PRDX1, TRX1 and oxidative stress biomarkers in blood samples of pregnant women with preeclampsia.

STUDY DESIGN

Twelve patients with preeclampsia (PE) were enrolled into the study. Seven third trimester healthy pregnant women (HP) were accepted as control group.

MAIN OUTCOME MEASURES

Peripheral venous blood samples of healthy and preeclamptic pregnant women were analyzed. Plasma level of advanced oxidation protein products (AOPP) was determined by spectrophotometry. The exofacial PRDX1 and TRX1 expression of lymphocytes and monocytes was detected by flow cytometry.

RESULTS

The plasma AOPP level was significantly higher in preeclampsia compared to the healthy pregnant group. Significantly higher percentage of PRDX1 and TRX1 expressing lymphocytes and monocytes were detected in the blood samples of preeclamptic women compared to healthy pregnant controls. The ratio of circulating PRDX1 and TRX1 expressing lymphocytes and monocytes showed a significant inverse correlation with the birth weight of newborns.

CONCLUSIONS

We have revealed that the level of advanced oxidation protein products is increased and the exofacial peroxiredoxin-1 and thioredoxin-1 system in lymphocytes and monocytes is upregulated in preeclampsia. In addition, the ratio of peroxiredoxin-1 and thioredoxin-1 positive circulating lymphocytes and monocytes correlates inversely with the neonatal birth weight, which finding indicates that pregnancies complicated by intrauterine growth restriction are accompanied by a higher level of oxidative stress.

Oleuropein Attenuates Oxidative Stress in Human Trophoblast Cells

Olive-derived bioactive compound oleuropein was evaluated against damage induced by hydrogen peroxide in human trophoblast cells in vitro, by examining the changes in several markers implicated in oxidative stress interactions in the placenta. Trophoblast HTR-8/SVneo cells were preincubated with OLE at 10 and 100 µM and exposed to H₂O₂, as a model of oxidative stress. Protein and lipid peroxidation, as well as antioxidant enzymes' activity, were determined spectrophotometrically, and DNA damage was evaluated by comet assay. iNOS protein expression was assessed by Western blot, while the mRNA expression of pro- and anti-apoptotic genes BAX and BCL2 and transcription factor NFE2L2, as well as cytokines IL-6 and TNF α were determined by qPCR. Oleuropein demonstrated cytoprotective effects against H₂O₂ in trophoblast cells by significantly improving the antioxidant status and preventing protein and lipid damage, as well as reducing the iNOS levels. OLE reduced the mRNA expression of IL-6 and TNF α, however, it did not influence the expression of NFE2L2 or the BAX/BCL2 ratio after H₂O₂ exposure. Oleuropein per se did not lead to any adverse effects in HTR-8/SVneo cells under the described conditions, confirming its safety in vitro. In conclusion, it significantly attenuated oxidative damage and restored antioxidant functioning, confirming its protective role in trophoblast.

Role of microRNAs in trophoblast invasion and spiral artery remodeling: Implications for preeclampsia

It is now well-established that microRNAs (miRNAs) are important regulators of gene expression. The role of miRNAs in placental development and trophoblast function is constantly expanding. Trophoblast invasion and their ability to remodel uterine spiral arteries are essential for proper placental development and successful pregnancy outcome. Many miRNAs are reported to be dysregulated in pregnancy complications, especially preeclampsia and they exert various regulatory effects on trophoblasts. In this review, we provide a brief overview of miRNA biogenesis and their mechanism of action, as well as of trophoblasts differentiation, invasion and spiral artery remodeling. We then discuss the role of miRNAs in trophoblasts invasion and spiral artery remodeling, focusing on miRNAs that have been thoroughly investigated, especially using multiple model systems. We also discuss the potential role of miRNAs in the pathogenesis of preeclampsia.

The Pathogenesis and Influencing Factors of Adult Hypertension Based on Structural Equation Scanning

Explore the pathogenesis and influencing factors of adult hypertension based on structural equation scanning. Using a multistage random sampling method, randomly select 2 community health service centers in each administrative area of a certain city and conduct a sample survey of residents in the community. According to the predetermined sample size n, multiply by 1.3 (1.3n) to draw a sample. Community doctors and medical students who have been uniformly trained form an investigation team draw up a questionnaire by consulting the literature, seek expert opinions, and then make changes based on the questions in the preinvestigation. Experiment result shows that the average systolic blood pressure of the experimental subjects was 126.13 + 15.36 mmHg and the average diastolic blood pressure was 79.52 + 8.81 mmHg; males are higher than females and increase with age. The prevalence rate of hyperemia is 26.3%, and the prevalence rate of prehypertension among the survey subjects is 55.4%; that of males (62.6%) is higher than that of females (49.2%). The prevalence of isolated systolic hypertension was 7.5%, and that of men (6.9%) was lower than that of women (7.9%). The awareness rate of hypertension was 66.5%, and the treatment rate of hypertension was 62.7%; the control rate of hypertension was 13.2%, and the control rate of hypertension treatment was 25.7%; all the abovementioned rates are higher for women than for men, and they all tend to increase with age which proved that being overweight is a risk factor for hypertension, dyslipidemia, and hypertension. Hypertension, dyslipidemia, and family history of hypertension are risk factors for hypertension. There is a positive correlation between hypertension and dyslipidemia.

Association of Keap1 (rs11085735) polymorphism and lncRNA MEG3 hypermethylation status with the risk of preeclampsia

Background

Preeclampsia (PE) is one of the complications of pregnancy. The pathogenesis of PE has not been completely understood. The aims of the present study were to investigate the role of Keap1 (rs11085735) variants and the methylation status of long non-coding RNA (lncRNA) MEG3 in the risk of PE.

Methods

In a case–control study, 150 pregnant women, including 75 PE patients and 75 healthy pregnant women recruited from Western Iran with Kurdish ethnic background, were studied for Keap1 variants using polymerase chain reaction‐restriction fragment length polymorphism (PCR-RFLP). The methylation status of lncRNA MEG3 was investigated using methylation-specific PCR (MSP) among 50 preeclamptic patients and 50 controls.

Results

The frequency of Keap1 A allele was significantly lower (5.3%) in preeclamptic patients compared to controls (12.7%, p = 0.024). The frequencies of hemimethylated (UM) and full methylated (MM) lncRNA MEG3 were 94 and 6% (p = 0.04), respectively, in all patients, 86.4, and 13.6% (p = 0.04), respectively, in patients with severe preeclampsia and 98 and 0% in controls. The frequency of full methylated lncRNA MEG3 was 14.3% in early-onset preeclampsia and 2.8% in late-onset preeclampsia (p = 0.12). Patients with PE had significantly higher levels of liver biomarkers (including ALT, AST, ALP, and total bilirubin) and lower PLT counts compared to healthy pregnant women.

Conclusion

The present study suggests the presence of hypermethylation status of lncRNA MEG3 in preeclampsia that might contribute to the pathogenesis and development of preeclampsia. Also, Keap1 rs11085735 polymorphism might be involved in the risk of preeclampsia.

Oxidative Stress in Arterial Hypertension (HTN): The Nuclear Factor Erythroid Factor 2-Related Factor 2 (Nrf2) Pathway, Implications and Future Perspectives

Arterial hypertension (HTN) is one of the most prevalent entities globally, characterized by increased incidence and heterogeneous pathophysiology. Among possible etiologies, oxidative stress (OS) is currently extensively studied, with emerging evidence showing its involvement in endothelial dysfunction and in different cardiovascular diseases (CVD) such as HTN, as well as its potential as a therapeutic target. While there is a clear physiological equilibrium between reactive oxygen species (ROS) and antioxidants essential for many cellular functions, excessive levels of ROS lead to vascular cell impairment with decreased nitric oxide (NO) availability and vasoconstriction, which promotes HTN. On the other hand, transcription factors such as nuclear factor erythroid factor 2-related factor 2 (Nrf2) mediate antioxidant response pathways and maintain cellular reduction-oxidation homeostasis, exerting protective effects. In this review, we describe the relationship between OS and hypertension-induced endothelial dysfunction and the involvement and therapeutic potential of Nrf2 in HTN.