Pathophysiology of Cerebral Vascular Dysfunction in Pregnancy-Induced Hypertension

Sex-based difference in selected stroke etiologies: cerebral dural sinus venous thrombosis, reversible cerebral vasoconstriction syndrome, dissection, migraine, pregnancy/puerperium/OC use

Females are at higher risk than males for a multitude of cerebrovascular conditions, both common and rare; partially resulting from a complex interplay between differing process involving genetics, hormonal influences, common cerebrovascular risk factors among others. Specific topics including cervical artery dissection, cerebral dural sinus venous thrombosis, reversible cerebral vasoconstriction syndrome, migraine, along with these disorders in the setting of pregnancy, puerperium and oral contraceptive utilization. Epidemiology, pathophysiology, presentation, basics of management and outcomes are presented, with sex differences throughout.

Up-regulation of Trim28 in pregnancy-induced hypertension is involved in the injury of human umbilical vein endothelial cells through the p38 signaling pathway

AIMS

The present study is to analyze the regulation and potential molecular mechanism of Trim28 on vascular endothelial injury induced by pregnancy-induced hypertension (PIH).

METHODS

Trim28 mRNA in placental tissues and peripheral blood from PIH patients were determined by quantitative real-time polymerase chain reaction. The serum from PIH was used to stimulate human umbilical vein endothelial cells (HUVECs). After silencing Trim28 in HUVECs, we used CCK-8 assay, Transwell assay and flow cytometry to investigate proliferation, migration and apoptosis. Western blotting was used to measure Trim28 protein level and p38 phosphorylation level. After addition of p38 inhibitor, the proliferation, migration and apoptosis of HUVECs with silenced Trim28 were studied again.

RESULTS

Trim28 expression in placental tissues and peripheral blood from PIH patients is elevated, and serum from these patients can up-regulate the expression of Trim28 in HUVECs in vitro. Trim28 silencing significantly inhibits the proliferation and migration of HUVECs by affecting the cell cycle. Down-regulation of Trim28 expression promotes the apoptosis of HUVECs. Trim28 regulates the biological function of HUVECs by affecting the activity of the p38 signaling pathway.

CONCLUSIONS

The present study demonstrates that Trim28 is up-regulated in peripheral blood of patients with PIH and participates in HUVECs injury through the p38 signaling pathway.

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.

CTRP9 alleviates hypoxia/reoxygenation-induced human placental vascular endothelial cells impairment and mitochondrial dysfunction through activating AMPK/Nrf2 signaling

BACKGROUND

Pregnancy-induced hypertension (PIH) is associated with significant maternal and fetal mortality. The present study is aimed at exploring the molecular mechanism of C1q/TNF-related protein 9 (CTRP9) in PIH.

METHODS

Human placental vascular endothelial cells (HPVECs) underwent hypoxia/reoxygenation (H/R) to construct an in vitro PIH cellular model. Cell transfection was conducted to over-express CTRP9. The expression level of CTRP9 was determined by western blot and quantitative real-time PCR. CCK-8, flow cytometry, wound-healing and tube formation assays were conducted to assess cell viability, apoptosis, migration and angiogenesis, respectively. Mitochondrial membrane potential (∆ψm) was evaluated adopting JC-1 staining. Mitochondrial ROS and copy number (mtDNA) were examined using superoxide indicator and real-time PCR, respectively. Then, HPVECs were pre-treated with Compound C (CC), the inhibitor of AMPK, for regulatory mechanism research.

RESULTS

CTRP9 was downregulated in HPVECs exposed to H/R induction. CTRP9 overexpression retards H/R-mediated cell viability loss and apoptosis, impaired migration and angiogenesis of HPVECs. Meanwhile, CTRP9 overexpression alleviates H/R-mediated mitochondrial dysfunction in HPVECs by enhancing mitochondrial ∆ψm, reducing mitochondrial ROS generation and increasing mtDNA copies. In addition, CTRP9 activated AMPK/Nrf2 signaling in H/R-mediated HPVECs, and additional treatment of CC greatly weakened the functional effects of CTRP9 in H/R-mediated HPVECs.

CONCLUSION

Our results suggested that CTRP9 protected against H/R-mediated HPVECs injuries dependent on AMPK/Nrf2 signaling and could be applied as a potential therapy for PIH.

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.

Hypertensive disorders of pregnancy and long-term risk of maternal stroke-a systematic review and meta-analysis

OBJECTIVE

Hypertensive disorders of pregnancy are associated with a long-term risk for cardiovascular disease among parous patients later in life. However, relatively little is known about whether hypertensive disorders of pregnancy are associated with an increased risk for ischemic stroke or hemorrhagic stroke in later life. This systematic review aimed to synthesize the available literature on the association between hypertensive disorders of pregnancy and the long-term risk for maternal stroke.

DATA SOURCES

PubMed, Web of Science, and CINAHL were searched from inception to December 19, 2022.

STUDY ELIGIBILITY CRITERIA

Studies were only included if the following criteria were met: case-control or cohort studies that were conducted with human participants, were available in English, and that measured the exposure of a history of hypertensive disorders of pregnancy (preeclampsia, gestational hypertension, chronic hypertension, or superimposed preeclampsia) and the outcome of maternal ischemic stroke or hemorrhagic stroke.

METHODS

Three reviewers extracted the data and appraised the study quality following the Meta-analyses of Observational Studies in Epidemiology guidelines and using the Newcastle-Ottawa scale for risk of bias assessment.

RESULTS

The primary outcome was any stroke (undifferentiated) and secondary outcomes included ischemic stroke and hemorrhagic stroke. The protocol for this systematic review was registered in the International Prospective Register of Systematic Reviews under identifier CRD42021254660. Of 24 studies included (10,632,808 study participants), 8 studies examined more than 1 outcome of interest. Hypertensive disorders of pregnancy were significantly associated with any stroke (adjusted risk ratio, 1.74; 95% confidence interval, 1.45-2.10). Preeclampsia was significantly associated with any stroke (adjusted risk ratio, 1.75; 95% confidence interval, 1.56-1.97), ischemic stroke (adjusted risk ratio, 1.74; 95% confidence interval, 1.46-2.06), and hemorrhagic stroke (adjusted risk ratio, 2.77; 95% confidence interval, 2.04-3.75). Gestational hypertension was significantly associated with any stroke (adjusted risk ratio, 1.23; 95% confidence interval, 1.20-1.26), ischemic stroke (adjusted risk ratio, 1.35; 95% confidence interval, 1.19-1.53), and hemorrhagic stroke (adjusted risk ratio, 2.66; 95% confidence interval, 1.02-6.98). Chronic hypertension was associated with ischemic stroke (adjusted risk ratio, 1.49; 95% confidence interval, 1.01-2.19).

CONCLUSION

In this meta-analysis, exposure to hypertensive disorders of pregnancy, including preeclampsia and gestational hypertension, seems to be associated with an increased risk for any stroke and ischemic stroke among parous patients in later life. Preventive interventions may be warranted for patients who experience hypertensive disorders of pregnancy to reduce their long-term risk for stroke.

Preeclampsia: Recent Advances in Predicting, Preventing, and Managing the Maternal and Fetal Life-Threatening Condition

Preeclampsia accounts for one of the most common documented gestational complications, with a prevalence of approximately 2 to 15% of all pregnancies. Defined as gestational hypertension after 20 weeks of pregnancy and coexisting proteinuria or generalized edema, and certain forms of organ damage, it is life-threatening for both the mother and the fetus, in terms of increasing the rate of mortality and morbidity. Preeclamptic pregnancies are strongly associated with significantly higher medical costs. The maternal costs are related to the extra utility of the healthcare system, more resources used during hospitalization, and likely more surgical spending due to an elevated rate of cesarean deliveries. The infant costs also contribute to a large percentage of the expenses as the babies are prone to preterm deliveries and relevant or causative adverse events. Preeclampsia imposes a considerable financial burden on our societies. It is important for healthcare providers and policy-makers to recognize this phenomenon and allocate enough economic budgets and medical and social resources accordingly. The true cellular and molecular mechanisms underlying preeclampsia remain largely unexplained, which is assumed to be a two-stage process of impaired uteroplacental perfusion with or without prior defective trophoblast invasion (stage 1), followed by general endothelial dysfunction and vascular inflammation that lead to systemic organ damages (stage 2). Risk factors for preeclampsia including race, advanced maternal age, obesity, nulliparity, multi-fetal pregnancy, and co-existing medical disorders, can serve as warnings or markers that call for enhanced surveillance of maternal and fetal well-being. Doppler ultrasonography and biomarkers including the mean arterial pressure (MAP), uterine artery pulsatility index (UtA-PI), and serum pregnancy-associated plasma protein A (PAPP-A) can be used for the prediction of preeclampsia. For women perceived as high-risk individuals for developing preeclampsia, the administration of low-dose aspirin on a daily basis since early pregnancy has proven to be the most effective way to prevent preeclampsia. For preeclamptic females, relevant information, counseling, and suggestions should be provided to facilitate timely intervention or specialty referral. In pregnancies complicated with preeclampsia, closer monitoring and antepartum surveillance including the Doppler ultrasound blood flow study, biophysical profile, non-stress test, and oxytocin challenge test can be arranged. If the results are unfavorable, early intervention and aggressive therapy should be considered. Affected females should have access to higher levels of obstetric units and neonatal institutes. Before, during, and after delivery, monitoring and preparation should be intensified for affected gravidas to avoid serious complications of preeclampsia. In severe cases, delivery of the fetus and the placenta is the ultimate solution to treat preeclampsia. The current review is a summary of recent advances regarding the knowledge of preeclampsia. However, the detailed etiology, pathophysiology, and effect of preeclampsia seem complicated, and further research to address the primary etiology and pathophysiology underlying the clinical manifestations and outcomes is warranted.

Brain Vascular Dysfunction in Mothers and Their Children Exposed to Preeclampsia

Preeclampsia is a maternal syndrome characterized by the new onset of hypertension and proteinuria after 20 weeks of gestation associated with multisystemic complications, including brain alterations. Indeed, brain complications associated with preeclampsia are the leading direct causes of fetal and maternal morbidity and mortality, especially in low- and middle-income countries. In addition to the well-recognized long-term adverse cardiovascular effects of preeclampsia, women who have had preeclampsia have higher risk of stroke, dementia, intracerebral white matter lesions, epilepsy, and perhaps also cognitive decline postpartum. Furthermore, increasing evidence has also associated preeclampsia with similar cognitive and cerebral disorders in the offspring. However, the mechanistic links between these associations remain unresolved. This article summarizes the current knowledge about the cerebrovascular complications elicited by preeclampsia and the potential pathophysiological mechanisms involved, emphasizing the impaired brain vascular function in the mother and their offspring.

Is there a role of proinflammatory cytokines on degenerin-mediated cerebrovascular function in preeclampsia?

Preeclampsia (PE) is associated with adverse cerebrovascular effects during and following parturition including stroke, small vessel disease, and vascular dementia. A potential contributing factor to the cerebrovascular dysfunction is the loss of cerebral blood flow (CBF) autoregulation. Autoregulation is the maintenance of CBF to meet local demands with changes in perfusion pressure. When perfusion pressure rises, vasoconstriction of cerebral arteries and arterioles maintains flow and prevents the transfer of higher systemic pressure to downstream microvasculature. In the face of concurrent hypertension, loss of autoregulatory control exposes small delicate microvessels to injury from elevated systemic blood pressure. While placental ischemia is considered the initiating event in the preeclamptic cascade, the factor(s) mediating cerebrovascular dysfunction are poorly understood. Elevated plasma proinflammatory cytokines, such as tumor necrosis factor α (TNF-α) and interleukin-17 (IL-17), are potential mediators of autoregulatory loss. Impaired CBF responses to increases in systemic pressure are attributed to the impaired pressure-induced (myogenic) constriction of small cerebral arteries and arterioles in PE. Myogenic vasoconstriction is initiated by pressure-induced vascular smooth muscle cell (VSMC) stretch. Recent studies from our laboratory group indicate that proinflammatory cytokines impair the myogenic mechanism of CBF autoregulation via inhibition of vascular degenerin proteins, putative mediators of myogenic constriction in VSMCs. This brief review links studies showing the effect of proinflammatory cytokines on degenerin expression and CBF autoregulation to the pathological cerebral consequences of preeclampsia.

Maternal Adverse Outcomes in Hypertensive Disorders of Pregnancy and Their Association with Serum Adiponectin and Redox Markers

Background: Premature termination of pregnancy because of unmanageable maternal complications in hypertensive disorders of pregnancy (HDP) results in adverse neonatal outcome. Identification of biochemical derangements associated with maternal complications may help in the better medical management of the mother resulting in better neonatal outcomes. Method: Healthy pregnant women (C); pregnant women with gestational hypertension (GH), and preeclampsia (late [LP] and early [EP] onset) were studied. Maternal serum redox markers and adipokines were evaluated for their association with maternal complications. Results: Adiponectin levels were significantly raised in preeclampsia groups when compared with control and GH groups. Univariate and multivariate analysis confirmed that malondialdehyde (MDA) and total antioxidant status (TAS) were associated with eclampsia; adiponectin and TAS with HELLP syndrome; adiponectin, MDA and TAS with severe preeclampsia; and adiponectin with impaired renal function. Conclusion: We identified that increased serum adiponectin, MDA, and TAS were associated with adverse maternal outcomes.

Clinical and Imaging Data-Based Model for Predicting Reversible Posterior Leukoencephalopathy Syndrome (RPLS) in Pregnant Women With Severe Preeclampsia or Eclampsia and Analysis of Perinatal Outcomes

OBJECTIVE

This study aimed to investigate the risk factors of reversible posterior leukoencephalopathy syndrome (RPLS) in pregnant women with severe preeclampsia or eclampsia (SPE/E) based on a predicting model and to analyze the perinatal outcomes.

METHODS

From January 2015 to March 2020, 78 pregnant women data diagnosed with severe preeclampsia or eclampsia with cranial magnetic resonance imaging (MRI) and transcranial Doppler (TCD) screening in Xiangyang No. 1 People's Hospital and Jiangsu Province Hospital of Chinese Medicine were analyzed retrospectively. They were divided into the RPLS group (n = 33) and non-RPLS group (n = 45) based on the MRI results. The general clinical data (blood pressure, BMI, symptoms, and so forth), laboratory examination, TCD results, and perinatal outcomes in the two groups were compared. The risk factors of severe preeclampsia or eclampsia complicated with RPLS were analyzed by multivariate logistic regression. The prediction model and decision curve (DCA) were established according to the clinical-imaging data.

RESULTS

The univariate analysis showed that poor placental perfusion, hypertension emergency, use of two or more oral antihypertensive drugs, headache, white blood cell (WBC) count, platelet (PLT) count, lactate dehydrogenase (LDH), alanine aminotransferase (ALT), uric acid (UA), serum albumin (ALB), average flow velocity, and resistance index of the posterior cerebral and basilar arteries were significantly different in the RPLS group compared with the non-RPLS group (all P < 0.05). The multivariate logistic regression analysis showed that hypertensive emergency, headache, WBC, PLT, ALT, and average flow velocity of the basilar artery (BAAFV) were the risk factors in the RPLS group. The aforementioned clinical-imaging data modeling (general data model, laboratory examination model, TCD model, and combined model) showed that the combined model predicted RPLS better. DCA also confirmed that the net benefit of the combined model was higher. In addition, the incidence of postpartum hemorrhage, stillbirth, and preterm infants was higher in the RPLS group than in the non-RPLS group (all P < 0.05).

CONCLUSIONS

More postpartum complications were detected in pregnant women with severe preeclampsia or eclampsia complicated with RPLS. Hypertensive emergency, headache, WBC, PLT, ALT, and BAAFV were the important risk factors for RPLS. The combined model had a better effect in predicting RPLS.

Effects of Compound Danshen Injection Combined with Magnesium Sulfate on Pregnancy-Induced Hypertension Syndrome under the Guidance of Empirical Mode Decomposition Algorithm-Based Ultrasound Image

Objective

The study focused on the separation effects of ultrasound blood flow signal detection, based on empirical mode decomposition (EMD) algorithm, and the clinical efficacy of Compound Danshen injection and magnesium sulfate in the treatment of pregnancy-induced hypertension (PIH) syndrome.

Methods

The empirical mode decomposition (EMD) algorithm was optimized first and compared with other algorithms for the accuracy and stability in separation of blood flow signals. 80 patients with PIH syndrome undergoing ultrasound examination were selected as the research subjects and randomly divided into control group and observation group according to the actual treatment methods. 40 cases in the observation group were treated with Compound Danshen injection + magnesium sulfate, and 40 cases in the control group were treated with magnesium sulfate. After the treatment, the clinical indicators of the two groups of patients were analyzed.

Results

The accuracy and stability in separating blood flow signal of the optimized EMD algorithm were better than those of other algorithms. After treatment, the total effective rate and blood pressure control of the observation group were significantly better than those of the control group, and the incidence of adverse maternal and infant outcomes was significantly lower than that of the control group. After treatment, the endothelin-1 (ET-1), C-reactive protein (CRP), and homocysteine (Hcy) indexes of the two groups of patients decreased significantly, and the decrease level of the observation group was significantly greater than that of the control group (P < 0.05). The prothrombin time (PT), fibrinogen (FIB), activated partial thromboplastin time (APTT), and plasma thrombin time (TT) levels of the two groups after treatment were better than those before treatment, and the observation group was better than the control group (P < 0.05).

Conclusion

The optimized EMD algorithm is of great value for the separation of ultrasound blood flow signals. For patients with PIH syndrome, Compound Danshen injection combined with magnesium sulfate can be used as a treatment plan, which can improve maternal and infant outcomes; control blood pressure; reduce 24 h urine protein and serum ET-1, Hcy, and CRP levels; and improve coagulation function. It is worthy of promotion.

Neurovascular dysfunctions in hypertensive disorders of pregnancy

Hypertensive disorders in pregnancy pose a huge challenge to the socioeconomic stability of a community; being a major cause of maternal and neonatal morbidity and mortality during delivery. Although there have been recent improvements in management strategies, still, the diversified nature of the underlying pathogenesis undermines their effectiveness. Generally, these disorders are categorized into two; hypertensive disorders of pregnancy with proteinuria (pre-eclampsia and eclampsia) and hypertensive disorders of pregnancy without proteinuria (gestational and chronic hypertension). Each of these conditions may present with unique characteristics that have interwoven symptoms. However, the tendency of occurrence heightens in the presence of any pre-existing life-threatening condition(s), environmental, and/or other genetic factors. Investigations into the cerebrovascular system demonstrate changes in the histoarchitectural organization of neurons, the proliferation of glial cells with an associated increase in inflammatory cytokines. These are oxidative stress indicators which impose a deteriorating impact on the structures that form the neurovascular unit and the blood-brain barrier (BBB). Such a pathologic state distorts the homeostatic supply of blood into the brain, and enhances the permeability of toxins/pathogens through a process called hyperperfusion at the BBB. Furthermore, a notable aspect of the pathogenesis of hypertensive disorders of pregnancy is endothelial dysfunction aggravated when signaling of the vasoprotective molecule, nitric oxide, amongst other neurotransmitter regulatory activities are impaired. This review aims to discuss the alterations in cerebrovascular regulation that determine the incidence of hypertension in pregnancy.

Prenatal intake of omega-3 promotes Wnt/β-catenin signaling pathway, and preserves integrity of the blood-brain barrier in preeclamptic rats

BACKGROUND

Preeclampsia is a systemic, multi-organ endotheliopathy, associated with oxidative injury to the blood-brain barrier (BBB). Preeclampsia initiates a cascade of events that include neuroinflammation. Recently, it was documented that Wnt/β-catenin signaling pathway exerts neuroprotective effects and maintain BBB integrity. We investigate the protective effect of omega-3 against neurovascular complication of preeclampsia and its relation to Wnt/β-catenin signaling pathway.

METHODOLOGY

After confirmation of day 0 pregnancy (G0), 24 adult pregnant female Wistar rats were divided into four groups control pregnant, pregnant supplemented with omega-3, preeclampsia (PE); female rats received N (ω)-nitro-L-arginine methyl ester (L-NAME) (50 mg/kg/day SC from day 7 to day 16 of pregnancy for induction of preeclampsia) and PE rats supplemented with omega-3. The intake of omega-3 started on day zero (0) of pregnancy until the end of the study (144 mg/kg\day orally).

RESULTS

We found that omega-3 supplementation significantly improved cognitive functions and EEG amplitude, decreased blood pressure, water contents of brain tissues, sFlt-1, oxidative stress, proteinuria, and enhanced Wnt\β-catenin proteins. Histological examination showed improved cerebral microangiopathy, increased expression of claudin-1 and -3, CD31, and VEGF in the cerebral cortical microvasculature and choroid plexus in PE rats treated with omega-3. A positive correlation between protein expression level of Wnt \β-catenin and cognitive functions, and a negative correlation between claudin-5 relative expression, claudin-1 and -3 area % from one side and water content of the brain tissues from the other side were observed.

CONCLUSION

Wnt/β-catenin signaling pathway suspected to have an important role to improve BBB integrity. Neuroprotective, antioxidant, and anti-inflammatory effects of omega-3 were observed and can be suggested as protective supplementation for preeclampsia.

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

Preeclampsia is characterized by increases in blood pressure and proteinuria in late pregnancy, and neurological symptoms can appear in the form of headaches, blurred vision, cerebral edema, and, in the most severe cases, seizures (eclampsia). The causes for these cerebral manifestations remain unknown, so the use of animal models that mimic preeclampsia is essential to understanding its pathogenesis. The Dahl salt-sensitive (Dahl SS/jr) rat model develops spontaneous preeclampsia superimposed on chronic hypertension; therefore, we hypothesized that the Dahl SS/jr rat would display cerebrovascular features similar to those seen in human preeclampsia. Furthermore, we predicted that this model would allow for the identification of mechanisms underlying these changes. The pregnant Dahl SS/jr rat displayed increased cerebral edema and blood-brain barrier disruption despite tighter control of cerebral blood flow autoregulation and vascular smooth muscle myogenic tone. Analysis of cerebral endothelial cell morphology revealed increased opening of tight junctions, basement membrane dissolution, and vesicle formation. RNAseq analysis identified that genes related to endothelial cell tight junctions and blood-brain barrier integrity were differentially expressed in cerebral vessels from pregnant Dahl SS/jr compared with healthy pregnant Sprague Dawley rats. Overall, our data reveal new insights into mechanisms involved in the cerebrovascular dysfunction of preeclampsia.NEW & NOTEWORTHY This study uses the Dahl SS/jr rat as a preclinical model of spontaneous superimposed preeclampsia to demonstrate uncoupling of cerebral vascular permeability and blood-brain barrier disruption from cerebral blood flow autoregulatory dysfunction and myogenic tone. Additionally, the data presented in this study lay the foundational framework on which future experiments assessing specific transcellular transport components such as individual transporter protein expression and components of the vesicular transport system (caveolae) can be built to help reveal a potential direct mechanistic insight into the causes of cerebrovascular complications during preeclamptic pregnancies.

Evaluation of chronic lead effects in the blood brain barrier system by DCE-CT

BACKGROUND

Lead (Pb) is an environmental factor has been suspected of contributing to the dementia including Alzheimer's disease (AD). Our previous studies have shown that Pb exposure at the subtoxic dose increased brain levels of beta-amyloid (Aβ) and amyloid plaques, a pathological hallmark for AD, in amyloid precursor protein (APP) transgenic mice, and is hypothesized to inhibit Aβ clearance in the blood- cerebrospinal fluid (CSF) barrier. However, it remains unclear how different levels of Pb affect Aβ clearance in the whole blood-brain barrier system. This study was designed to investigate whether chronic exposure of Pb affected the permeability of the blood-brain barrier system by using the Dynamic Contrast-Enhanced Computerized Tomography (DCE-CT) method.

METHODS

DEC-CT was used to investigate whether chronic exposure of toxic Pb affected the permeability of the real-time blood brain barrier system.

RESULTS

Data showed that Pb exposure increased permeability surface area product, and also significantly induced brain perfusion. However, Pb exposure did not alter extracellular volumes or fractional blood volumes of mouse brain.

CONCLUSION

Our data suggest that Pb exposure at subtoxic and toxic levels directly targets the brain vasculature and damages the blood brain barrier system.