Decrease in Nitric Oxide Production as a Key Mediator in the Pathogenesis of Preeclampsia and a Potential Therapeutic Target: A Case-Control 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.

Association of ACE*(Insertion/Deletion) Variant with the Elevated Risk of Preeclampsia Among Gestational Women

The renin-angiotensin-aldosterone system has an indispensable function in the uteroplacental circulation, placental growth, and blood pressure optimization. The angiotensin I converting enzyme (ACE) gene is a critical integrator for electrolyte balance, and water retention, along with inhibiting preeclampsia. The main goal of this pertaining study is to assess the contribution of ACE*(Ins/Del) variant with the susceptibility for preeclampsia with focus on the severity of the disease among gestational hypertensive women. This retrospective study included 225 participants [125 PE gestational women, and 100 normotensive healthy controls] matching with age, and geographical region. PE women classified into 82 early-onset PE women, accompanied with 43 late-onset PE women. Additionally, PE women categorized into 59 mild PE women, together with 66 severe PE women. The genotyping and characterization of ACE*(Ins/Del) variant were applied using the PCR technique. Our findings indicated higher frequency of the ACE*(Del/Del) genotype and ACE*(D allele) with elevated risk of preeclampsia compared to normotensive controls under recessive (OR = 2.09, and p-value = 0.007), and allelic (OR = 1.75, and p-value = 0.012) models. In addition, testing logistic regression revealed that the levels of endothelin-1 and malondialdehyde exposed significant difference for the ACE*(Del/Del) genotype among early-onset and late-onset PE women (p-value = 0.024, and 0.23, respectively). Furthermore, carriers of the ACE*(Del/Del) genotype observed statistically significant with lower sodium concentrations among severe PE women (p-value = 0.034). The ACE*(Del/Del) genotype and ACE*(D allele) were associated with increased risk preeclampsia among gestational women. Furthermore, early-onset PE and late-onset PE were correlated with endothelin-1 and malondialdehyde concentrations among Egyptian women.

Vasodilator Responses of Perivascular Adipose Tissue-Derived Hydrogen Sulfide Stimulated with L-Cysteine in Pregnancy Hypertension-Induced Endothelial Dysfunction in Rats

Endothelium-derived nitric oxide (NO)-induced vasodilation is impaired in pregnancy hypertension. However, the role of perivascular adipose tissue (PVAT)-derived hydrogen sulfide (H2S), as an alternative for counteracting vascular dysfunction, is incompletely clear in hypertensive disorders of pregnancy. Therefore, PVAT-derived H2S-induced vasodilation was investigated in pregnancy hypertension-induced endothelial dysfunction. Non-pregnant (Non-Preg) and pregnant (Preg) rats were submitted (or not) to the deoxycorticosterone (DOCA)-salt protocol and assigned as follows (n = 10/group): Non-Preg, Non-Preg+DOCA, Preg, and Preg+DOCA groups. Systolic blood pressure (SBP), angiogenesis-related factors, determinant levels of H2S (PbS), NO (NOx), and oxidative stress (MDA) were assessed. Vascular changes were recorded in thoracic aortas with PVAT and endothelium (intact and removed layers). Vasorelaxation responses to the substrate (L-cysteine) for the H2S-producing enzyme cystathionine-γ-lyase (CSE) were examined in the absence and presence of CSE-inhibitor DL-propargylglycine (PAG) in thoracic aorta rings pre-incubated with cofactor for CSE (pyridoxal-5 phosphate: PLP) and pre-contracted with phenylephrine. Hypertension was only found in the Preg+DOCA group. Preg+DOCA rats showed angiogenic imbalances and increased levels of MDA. PbS, but not NOx, showed increased levels in the Preg+DOCA group. Pre-incubation with PLP and L-cysteine elevated determinants of H2S in PVAT and placentas of Preg-DOCA rats, whereas no changes were found in the aortas without PVAT. Aortas of Preg-DOCA rats showed that PVAT-derived H2S-dependent vasodilation was greater compared to endothelium-derived H2S, whereas PAG blocked these responses. PVAT-derived H2S endogenously stimulated with the amino acid L-cysteine may be an alternative to induce vasorelaxation in endothelial dysfunction related to pregnancy hypertension.