Endothelial cell disruption drives increased blood-brain barrier permeability and cerebral edema in the Dahl SS/jr rat model of superimposed preeclampsia

Review: The potential role of placental extracellular vesicles in blood-brain barrier disruption and neuroinflammation in preeclampsia

Preeclampsia is a complex pregnancy disorder characterized by hypertension and multisystem organ damage, notably affecting the liver, kidneys, and brain. Eclampsia, a severe form of preeclampsia, is marked by the sudden onset of generalized tonic-clonic seizures. Brain complications, including eclampsia, are responsible for 60-70 % of preeclampsia-related maternal deaths, particularly in low-income regions. Despite the significant impact of brain complications in preeclampsia, their underlying pathophysiology remains unclear. Evidence suggests that brain edema in preeclampsia and eclampsia results from disruption of the blood-brain barrier (BBB). Although direct analysis of the BBB is challenging, in vitro studies indicate that plasma from women with preeclampsia can compromise the BBB, with the specific circulating factors involved still unidentified. Among the potential culprits, recent findings highlight placental-derived small extracellular vesicles (PDsEVs) as key players in BBB disruption observed in preeclampsia. This review examines the role of PDsEVs in the pathophysiology of brain edema associated with preeclampsia, emphasizing areas for future research, including neuroinflammation and neuron dysfunction. Additionally, we discuss the protective role of magnesium sulfate in these processes.

Inhibitory effect of exercise on elevated blood pressure and fetal growth restriction during pregnancy in Dahl salt-sensitive rats

Exercise is effective in preventing gestational hypertension, but its mechanism remains unclear. This study investigates the effects of exercise on Dahl salt-sensitive (DSS) rats, which develop elevated blood pressure and fetal growth restriction during pregnancy. DSS rats were divided into exercise and non-exercise groups, with Sprague-Dawley rats as controls. Exercise consisted of voluntary running, starting 4 weeks prior to pregnancy until the last trimester. Cardiovascular parameters, molecular characteristics of the brain and placenta, and fetal conditions were evaluated. Exercise significantly improved elevated blood pressure at early pregnancy and was associated with improved baroreceptor reflex gain. Gene expression analysis in the rostral ventrolateral medulla (RVLM) showed exercise-induced downregulation of nitric oxide synthase and upregulation of superoxide dismutase. These genetic changes suggest that exercise impacts circulatory regulation mechanisms, contributing to blood pressure improvement. In addition, placental analysis revealed a marked increase in placental growth factor expression due to exercise. In conclusion, exercise alleviates elevated blood pressure at early gestation and fetal growth restriction in DSS rats. Genetic modifications in the RVLM may play a critical role in exercise-induced cardiovascular improvements. This study highlights the potential of exercise as a therapeutic approach for managing gestational elevated blood pressure and fetal growth restriction and provides insights into its underlying mechanisms.

Guidelines for assessing maternal cardiovascular physiology during pregnancy and postpartum

Maternal mortality rates are at an all-time high across the world and are set to increase in subsequent years. Cardiovascular disease is the leading cause of death during pregnancy and postpartum, especially in the United States. Therefore, understanding the physiological changes in the cardiovascular system during normal pregnancy is necessary to understand disease-related pathology. Significant systemic and cardiovascular physiological changes occur during pregnancy that are essential for supporting the maternal-fetal dyad. The physiological impact of pregnancy on the cardiovascular system has been examined in both experimental animal models and in humans. However, there is a continued need in this field of study to provide increased rigor and reproducibility. Therefore, these guidelines aim to provide information regarding best practices and recommendations to accurately and rigorously measure cardiovascular physiology during normal and cardiovascular disease-complicated pregnancies in human and animal models.

Mucormycosis during COVID-19 era: A retrospective assessment

In a retrospective view, this review examines the impact of mucormycosis on health workers and researchers during the COVID era. The diagnostic and treatment challenges arising from unestablished underlying pathology and limited case studies add strain to healthcare systems. Mucormycosis, caused by environmental molds, poses a significant threat to COVID-19 patients, particularly those with comorbidities and compromised immune systems. Due to a variety of infectious Mucorales causes and regionally related risk factors, the disease's incidence is rising globally. Data on mucormycosis remains scarce in many countries, highlighting the urgent need for more extensive research on its epidemiology and prevalence. This review explores the associations between COVID-19 disease and mucormycosis pathology, shedding light on potential future diagnostic techniques based on the fungal agent's biochemical components. Medications used in ICUs and for life support in ventilated patients have been reported, revealing the challenge of managing this dual onslaught. To develop more effective treatment strategies, it is crucial to identify novel pharmacological targets through "pragmatic" multicenter trials and registries. In the absence of positive mycology culture data, early clinical detection, prompt treatment, and tissue biopsy are essential to confirm the specific morphologic features of the fungal agent. This review delves into the history, pathogens, and pathogenesis of mucormycosis, its opportunistic nature in COVID or immunocompromised individuals, and the latest advancements in therapeutics. Additionally, it offers a forward-looking perspective on potential pharmacological targets for future drug development.

Primary and Secondary Intracerebral Hemorrhage in Pregnant and Nonpregnant Young Adults by SMASH-UP Criteria

BACKGROUND

Intracerebral hemorrhage (ICH) is a major cause of maternal morbidity, but its pathophysiology is poorly characterized. We investigated characteristics of pregnancy-associated ICH (P-ICH), compared with ICH in similar aged nonpregnant adults of both sexes.

METHODS AND RESULTS

We performed a retrospective analysis of 134 adults aged 18 to 44 years admitted to our center with nontraumatic ICH from January 1, 2012, to December 31, 2021. We compared ICH characteristics among 3 groups: those with P-ICH (pregnant or within 12 months of end of pregnancy); nonpregnant women; and men. We categorized ICH pathogenesis according to a modified scheme, SMASH-UP (structural, medications, amyloid angiopathy, systemic, hypertension, undetermined, posterior reversible encephalopathy syndrome/reversible cerebral vasoconstriction syndrome), and calculated odds ratios and 95% CIs for primary (spontaneous small-vessel) ICH versus secondary ICH (structural lesions or coagulopathy related), using nonpregnant women as the reference. We also compared specific ICH pathogenesis by SMASH-UP criteria and functional outcomes between groups. Of 134 young adults with nontraumatic ICH, 25 (19%) had P-ICH, of which 60% occurred postpartum. Those with P-ICH had higher odds of primary ICH compared with nonpregnant women (adjusted odds ratio, 4.5 [95% CI, 1.4-14.7]). The odds of primary ICH did not differ between men and nonpregnant women. SMASH-UP pathogenesis for ICH differed significantly between groups (P<0.001). While the in-hospital mortality rate was lowest in the P-ICH group (4%) compared with nonpregnant women (13%) and men (24%), 1 in 4 patients with P-ICH were bedbound and dependent at the time of discharge.

CONCLUSIONS

In our cohort of young adults with ICH, 1 in 5 was pregnancy related. P-ICH differed in pathogenesis compared with non-pregnancy-related ICH in young adults, suggesting unique pathophysiology.

Blood-Brain Barrier Dysfunction in Hypertensive Disorders of Pregnancy

PURPOSE OF REVIEW

The incidence of hypertensive disorders of pregnancy (HDP), especially preeclampsia has increased significantly over the last two decades. Patients with these disorders often report cerebral and visual symptoms, which are listed as potential diagnosis criteria for preeclampsia, if accompanied by new-onset hypertension. Recent studies indicate that cerebral complications in HDP patients are associated with a compromised blood-brain barrier (BBB). The purpose of this review is to highlight the recent literature focused on the BBB in HDP, identify gaps in knowledge, and discuss future directions in this research area.

RECENT FINDINGS

Majority of the studies addressing BBB changes in HDP are focused on preeclampsia. Recent studies show that hypertension induces increased association of perivascular macrophages/microglia to the cerebral vessels, increased circulating extracellular vesicles, and decreased autoregulation of cerebral blood flow. There is a critical need for more animal studies targeted to protecting the BBB and preventing cerebrovascular complications in the context of HDP. More clinical studies are needed that investigate both the short- and long-term interplay between each HDP subtype and BBB and cognitive function.

AT1-AA Infusion during Pregnancy Impairs CBF Autoregulation Postpartum

Preeclampsia (PE), new-onset hypertension during pregnancy alongside organ dysfunction, is a leading cause of morbidity and mortality for the mother and fetus. PE women have activated B cells that produce agonistic autoantibodies to the angiotensin II type 1 receptor (AT1-AA). AT1-AA impairs cerebral blood flow (CBF) autoregulation during pregnancy. Although AT1-AA often remains elevated up to 8 years postpartum, AT1-AA's effect on CBF autoregulation postpartum is unknown. This study examined whether elevated AT1-AA during pregnancy impairs CBF autoregulation postpartum and if this was augmented by infusion of AT1-AA postpartum. AT1-AA was infused into 12-week-old timed-pregnant Sprague Dawley rats beginning on gestational day 14. Uterine artery resistance index (UARI) was measured on gestational day 18 as a measure of endothelial dysfunction associated with PE. Dams were allowed to deliver. One group was given a second infusion of AT1-AA (50% perinatal dose mimicking levels observed in postpartum PE women) at 9 weeks postpartum. After postpartum week 10, mean arterial pressure (MAP) was measured in conscious rats and CBF autoregulation was measured by laser Doppler flowmetry. AT1-AA during pregnancy increased UARI (P<0.05). AT1-AA during pregnancy did not affect MAP postpartum but did impair CBF autoregulation postpartum. Infusion of AT1-AA postpartum significantly elevated blood pressure (P<0.01) but did not further impair CBF autoregulation. This study demonstrates that circulating AT1-AA during pregnancy causes impairment of CBF autoregulation well into the postpartum period indicating that elevated AT1-AA leads to long-term cerebrovascular consequences. Targeting AT1-AA may prevent cerebrovascular effects associated with PE during pregnancy and postpartum.

Preeclampsia history and postpartum risk of cerebrovascular disease and cognitive impairment: Potential mechanisms

Hypertensive disorders of pregnancy such as preeclampsia, eclampsia, superimposed preeclampsia, and gestational hypertension are major causes of fetal and maternal morbidity and mortality. Women with a history of hypertensive pregnancy disorders have increased risk of stroke and cognitive impairments later in life. Moreover, women with a history of preeclampsia have increased risk of mortality from diseases including stroke, Alzheimer's disease, and cardiovascular disease. The underlying pathophysiological mechanisms are currently not fully known. Here, we present clinical, epidemiological, and preclinical studies focused on evaluating the long-term cerebrovascular and cognitive dysfunction that affect women with a history of hypertensive pregnancy disorders and discuss potential underlying pathophysiological mechanisms.

Stigmasterol protects human brain microvessel endothelial cells against ischemia-reperfusion injury through suppressing EPHA2 phosphorylation

Stigmasterol is a plant sterol with anti-apoptotic, anti-oxidative and anti-inflammatory effect through multiple mechanisms. In this study, we further assessed whether it exerts protective effect on human brain microvessel endothelial cells (HBMECs) against ischemia-reperfusion injury and explored the underlying mechanisms. HBMECs were used to establish an in vitro oxygen and glucose deprivation/reperfusion (OGD/R) model, while a middle cerebral artery occlusion (MCAO) model of rats were constructed. The interaction between stigmasterol and EPHA2 was detected by surface plasmon resonance (SPR) and cellular thermal shift assay (CETSA). The results showed that 10 μmol·L^-1 stigmasterol significantly protected cell viability, alleviated the loss of tight junction proteins and attenuated the blood-brain barrier (BBB) damage induced by OGD/R in thein vitro model. Subsequent molecular docking showed that stigmasterol might interact with EPHA2 at multiple sites, including T692, a critical gatekeep residue of this receptor. Exogenous ephrin-A1 (an EPHA2 ligand) exacerbated OGD/R-induced EPHA2 phosphorylation at S897, facilitated ZO-1/claudin-5 loss, and promoted BBB leakage in vitro, which were significantly attenuated after stigmasterol treatment. The rat MCAO model confirmed these protective effects in vivo. In summary, these findings suggest that stigmasterol protects HBMECs against ischemia-reperfusion injury by maintaining cell viability, reducing the loss of tight junction proteins, and attenuating the BBB damage. These protective effects are at least meditated by its interaction with EPHA2 and inhibitory effect on EPHA2 phosphorylation.

Preeclampsia and the Kidney: Pathophysiology and Clinical Implications

Preeclampsia and other hypertensive disorders of pregnancy are major contributors to maternal morbidity and mortality worldwide. This group of disorders includes chronic hypertension, gestational hypertension, preeclampsia, preeclampsia superimposed on chronic hypertension, and eclampsia. The body undergoes important physiological changes during pregnancy to allow for normal placental and fetal development. Several mechanisms have been proposed that may lead to preeclampsia, including abnormal placentation and placental hypoxia, impaired angiogenesis, excessive pro-inflammatory response, immune system imbalance, abnormalities of cellular senescence, alterations in regulation and activity of angiotensin II, and oxidative stress, ultimately resulting in upregulation of multiple mediators of endothelial cell dysfunction leading to maternal disease. The clinical implications of preeclampsia are significant as there are important short-term and long-term health consequences for those affected. Preeclampsia leads to increased risk of preterm delivery and increased morbidity and mortality of both the developing fetus and mother. Preeclampsia also commonly leads to acute kidney injury, and women who experience preeclampsia or another hypertensive disorder of pregnancy are at increased lifetime risk of chronic kidney disease and cardiovascular disease. An understanding of normal pregnancy physiology and the pathophysiology of preeclampsia is essential to develop novel treatment approaches and manage patients with preeclampsia and hypertensive disorders of pregnancy. © 2023 American Physiological Society. Compr Physiol 13:4231-4267, 2023.

Pial Vessel-Associated Microglia/Macrophages Increase in Female Dahl-SS/Jr Rats Independent of Pregnancy History

As the resident immune cells of the central nervous system, microglia have a wide range of functions such as surveillance, phagocytosis, and signaling through production of chemokines and cytokines. Recent studies have identified and characterized macrophages residing at the meninges, a series of layers surrounding the brain and spinal cord. While perivascular microglia within the brain parenchyma increase following chronic hypertension, there are no reports of changes at the meninges, and specifically, associated with the pial vasculature. Thus, we used female Sprague Dawley and Dahl salt-sensitive (SS/Jr) rat brains, stained for ionized calcium-binding adapter molecule (Iba1), and characterized microglia/macrophages associated with pial vessels in the posterior brain. Results indicate that Iba1+ pial vessel-associated microglia (PVAM) completely surrounded the vessels in brains from the Dahl-SS/Jr rats. PVAM density was significantly higher and distance between PVAMs lower in Dahl-SS/Jr compared to the Sprague Dawley rat brains. Pregnancy history did not affect these findings. While the functional role of these cells are not known, we contextualize our novel findings with that of other studies assessing or characterizing myeloid cells at the borders of the CNS (meninges and choroid plexus) and perivascular macrophages and propose their possible origin in the Dahl-SS/Jr model of chronic hypertension.

L-citrulline ameliorates pathophysiology in a rat model of superimposed preeclampsia

BACKGROUND AND PURPOSE

Preeclampsia, characterized by hypertension, proteinuria, and fetal growth restriction, is one of the leading causes of maternal and perinatal mortality. By far, there is no effective pharmacological therapy for preeclampsia. The present study was conducted to investigate the effects of L-citrulline supplementation in Dahl salt-sensitive rat, a model of superimposed preeclampsia.

EXPERIMENTAL APPROACH

Parental DSSR were treated with L-citrulline (2.5 g/L in drinking water) from the day of mating to the end of lactation period. Blood pressure of the rats was monitored throughout pregnancy and markers of preeclampsia were assessed. Endothelial function of the pregnant DSSR was assessed by wire myograph.

KEY RESULTS

L-citrulline supplementation significantly reduced maternal blood pressure, proteinuria, and levels of circulating soluble fms-like tyrosine kinase 1 in DSSR. L-citrulline improved maternal endothelial function by augmenting the production of nitric oxide in the aorta and improving endothelium-derived hyperpolarizing factor-mediated vasorelaxation in resistance arteries. L-citrulline supplementation improved placental insufficiency and fetal growth, which were associated with an enhancement of angiogenesis and reduction of fibrosis and senescence in the placentas. In addition, L-citrulline downregulated genes involved in the toll-like receptor 4 and nuclear factor-κB signaling pathway.

CONCLUSION AND IMPLICATIONS

This study shows that L-citrulline supplementation reduces gestational hypertension, improves placentation and fetal growth in a rat model of superimposed preeclampsia. L-citrulline supplementation may represent an effective and safe therapeutic strategy for preeclampsia that benefit both the mother and the fetus.

Pathogenic mechanisms of preeclampsia with severe features implied by the plasma exosomal mirna profile

Preeclampsia is a complication of pregnancy characterized by high blood pressure and organ damage after 20 gestational weeks. It is associated with high maternal and fetal morbidity and mortality. However, at present, there is no effective prevention or treatment for this condition. Previous studies have revealed that plasma exosomal mirnas from pregnant women with preeclampsia could serve as biomarkers of pathogenic factors. However, the roles of plasma exosomal mirnas in preeclampsia with severe features (sPE), which is associated with poorer pregnancy outcomes, remain unknown. Thus, the aims of this study were to characterize plasma exosomal miRNAs in sPE and explore the related pathogenic mechanisms using bioinformatic analysis. Plasma exosomes were isolated using a mirVana RNA isolation kit. the exosomal miRNAs were detected using high-throughput sequencing and the mirnas related to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways and gene ontology (GO) terms were analyzed using the clusterprofiler package of R. Fifteen miRNAs exhibited increased expression and fourteen miRNAs exhibited reduced expression in plasma exosomes from women with sPE as compared to normal pregnant women. Further, gene set enrichment analysis revealed that the differentially expressed plasma exosomal miRNAs were related to the stress response and cell junction regulation, among others. In summary, this study is the first to identify the differentially expressed plasma exosomal miRNAs in sPE. These findings highlight promising pathogenesis mechanisms underlying preeclampsia.

Superior antioxidant and anti-ischemic neuroprotective effects of cerebrolysin in heat stroke following intoxication of engineered metal Ag and Cu nanoparticles: A comparative biochemical and physiological study with other stroke therapies

Military personnel are often exposed to high environmental heat associated with industrial or ambient abundance of nanoparticles (NPs) affecting brain function. We have shown that engineered metal NPs Ag and Cu exacerbate hyperthermia induced brain pathology. Thus, exploration of novel drug therapy is needed for effective neuroprotection in heat stroke intoxicated with NPs. In this investigation neuroprotective effects of cerebrolysin, a balanced composition of several neurotrophic factors and active peptides fragments exhibiting powerful antioxidant and anti-ischemic effects was examined in heat stroke after NPs intoxication. In addition, its efficacy is compared to currently used drugs in post-stroke therapies in clinics. Thus, levertiracetam, pregabalin, topiramat and valproate were compared in standard doses with cerebrolysin in heat stroke intoxicated with Cu or Ag NPs (50-60nm, 50mg/kg, i.p./day for 7 days). Rats were subjected to 4h heat stress (HS) in a biological oxygen demand incubator at 38°C (Relative Humidity 45-47%; Wind velocity 22.4-25.6cm/s) that resulted in profound increase in oxidants Luminol, Lucigenin, Malondialdehyde and Myeloperoxidase, and a marked decrease in antioxidant Glutathione. At this time severe reductions in the cerebral blood flow (CBF) was seen together with increased blood-brain barrier (BBB) breakdown and brain edema formation. These pathophysiological responses were exacerbated in NPs treated heat-stressed animals. Pretreatment with cerebrolysin (2.5mL/kg, i.v.) once daily for 3 days significantly attenuated the oxidative stress, BBB breakdown and brain edema and improved CBF in the heat stressed group. The other drugs were least effective on brain pathology following heat stroke. However, in NPs treated heat stressed animals 5mL/kg conventional cerebrolysin and 2.5mL/kg nanowired cerebrolysin is needed to attenuate oxidative stress, BBB breakdown, brain edema and to improve CBF. Interestingly, the other drugs even in higher doses used are unable to alter brain pathologies in NPs and heat stress. These observations are the first to demonstrate that cerebrolysin is the most superior antioxidant and anti-ischemic drug in NPs exposed heat stroke, not reported earlier.