The cerebral circulation during pregnancy: adapting to preserve normalcy

Predictors of early intracerebral hemorrhage in patients with cerebral sinus venous thrombosis: Systematic review and meta-analysis

OBJECTIVES

Patients with cerebral venous thrombosis (CVT) may present with early intracerebral hemorrhage (EICH). The objective of this study was to identify predictors for EICH in CVT patients via a systematic review and meta-analysis of observational studies. Additionally, we aimed to evaluate the clinical outcomes associated with the presence of EICH in these patients.

METHODS

Literature search on PubMed, EMBASE and Cochrane Library databases from inception up to 1 February 2024 was conducted. Five studies with predictors of EICH were included in qualitative synthesis and meta-analysis.

RESULTS

Pooled analysis demonstrated a statistically significant association between female gender and EICH (odd ratios (OR) = 1.51, 95 % confidence interval (CI) = 1.23-1.85, p < 0.01). The ICH patients had higher likelihood of seizures (OR = 3.07, 95 % CI = 1.69-5.58, p < 0.01), focal neurological deficits (OR = 4.07, 95 % CI = 2.57-6.44, p < 0.01), and decreased level of consciousness (OR = 3.89, 95 % CI = 2.53-5.87, p < 0.01). Superior Sagittal Sinus thrombosis was associated with higher likelihood of EICH (OR: 1.49, 95 % CI 1.05-2.13, P = 0.03). No statistically significant association was demonstrated between presence of EICH and pregnancy, presence of hematological diseases or thrombophilia, or other site of venous thrombosis (deep venous system, or multiple sinuses involvement). Furthermore, patients who exhibited early EICH were notably less likely to attain a favorable functional outcome (mRS 0-2) (OR: 0.28; 95 % CI 0.16-0.49; p < 0.001).

CONCLUSION

This meta-analysis demonstrates that among CVT patients, female patients with new onset seizures, focal neurological deficits and decreased level of consciousness are more likely to present with EICH.

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.

Arteriovenous malformation-related headache and seizures in pregnancy masquerading as eclampsia: A case report

OBJECTIVE

Cerebral arteriovenous malformation during pregnancy is rare but lethal disease that usually present with new-onset seizures and headaches mimicking eclampsia. We report a rare case of cerebral arteriovenous malformation with abrupt seizures in the third trimester.

CASE REPORT

A 28-year-old primipara was brought to our emergency department at 32 6/7 weeks of gestation with new-onset acute seizures and hypertension. Owing to neurological deterioration, the patient underwent emergency cesarean delivery. However, 24 h after cesarean delivery and eclampsia treatment, the seizures worsened. Computed tomography and magnetic resonance imaging showed unruptured arteriovenous malformation of the right frontal lobe. Subsequently, intraarterial embolization was performed. The patient was discharged 5 days after surgery without neurological sequelae or obstetric complications.

CONCLUSION

This case report highlights the differential diagnoses of sudden new-onset seizures in late pregnancy for obstetricians and emergency medicine physicians. Lethal cerebral diseases, apart from eclampsia, should be considered during pregnancy.

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.

Effects of reproductive experience on cost-benefit decision making in female rats

Many individuals undergo mating and/or other aspects of reproductive experience at some point in their lives, and pregnancy and childbirth in particular are associated with alterations in the prevalence of several psychiatric disorders. Research in rodents shows that maternal experience affects spatial learning and other aspects of hippocampal function. In contrast, there has been little work in animal models concerning how reproductive experience affects cost-benefit decision making, despite the relevance of this aspect of cognition for psychiatric disorders. To begin to address this issue, reproductively experienced (RE) and reproductively naïve (RN) female Long-Evans rats were tested across multiple tasks that assess different forms of cost-benefit decision making. In a risky decision-making task, in which rats chose between a small, safe food reward and a large food reward accompanied by variable probabilities of punishment, RE females chose the large risky reward significantly more frequently than RN females (greater risk taking). In an intertemporal choice task, in which rats chose between a small, immediate food reward and a large food reward delivered after a variable delay period, RE females chose the large reward less frequently than RN females. Together, these results show distinct effects of reproductive experience on different forms of cost-benefit decision making in female rats, and highlight reproductive status as a variable that could influence aspects of cognition relevant for psychiatric disorders.

Cerebrospinal fluid and arterial acid-base equilibria in spontaneously breathing third-trimester pregnant women

BACKGROUND

Acid-base status in full-term pregnant women is characterised by hypocapnic alkalosis. Whether this respiratory alkalosis is primary or consequent to changes in CSF electrolytes is not clear.

METHODS

We enrolled third-trimester pregnant women (pregnant group) and healthy, non-pregnant women of childbearing age (controls) undergoing spinal anaesthesia for Caesarean delivery and elective surgery, respectively. Electrolytes, strong ion difference (SID), partial pressure of carbon dioxide ( [Formula: see text] ), and pH were measured in simultaneously collected CSF and arterial blood samples.

RESULTS

All pregnant women (20) were hypocapnic, whilst only four (30%) of the controls (13) had an arterial [Formula: see text] <4.7 kPa (P<0.001). The incidence of hypocapnic alkalosis was higher in the pregnant group (65% vs 8%; P=0.001). The CSF-to-plasma Pco₂ difference was significantly higher in pregnant women (1.5 [0.3] vs 1.0 [0.4] kPa; P<0.001), mainly because of a decrease in arterial Pco₂ (3.9 [0.3] vs 4.9 [0.5] kPa; P<0.001). Similarly, the CSF-to-plasma difference in SID was less negative in pregnant women (-7.8 [1.4] vs -11.4 [2.3] mM; P<0.001), mainly because of a decreased arterial SID (31.5 [1.2] vs 36.1 [1.9] mM; P<0.001). The major determinant of the reduced plasma SID of pregnant women was a relative increase in plasma chloride compared with sodium.

CONCLUSIONS

Primary hypocapnic alkalosis characterises third-trimester pregnant women leading to chronic acid-base adaptations of CSF and plasma. The compensatory SID reduction, mainly sustained by an increase in chloride concentration, is more pronounced in plasma than in CSF, as the decrease in Pco₂ is more marked in this compartment.

CLINICAL TRIAL REGISTRATION

NCT03496311.

Rank-Rankl-Opg Axis in Multiple Sclerosis: The Contribution of Placenta

Women with multiple sclerosis (MS) can safely become pregnant and give birth, with no side effects or impediments. Pregnancy is generally accepted as a period of well-being in which relapses have a softer evolution, particularly in the third trimester. Herein, we hypothesized that the placenta, via its “secretome”, could contribute to the recognized beneficial effects of pregnancy on MS activity. We focused on a well-known receptor/ligand/decoy receptor system, such as the one composed by the receptor activator of nuclear factor-kB (RANK), its ligand (RANKL), and the decoy receptor osteoprotegerin (OPG), which have never been investigated in an integrated way in MS, pregnancy, and placenta. We reported that pregnancy at the term of gestation influences the balance between circulating RANKL and its endogenous inhibitor OPG in MS women. We demonstrated that the placenta at term is an invaluable source of homodimeric OPG. By functional studies on astrocytes, we showed that placental OPG suppresses the mRNA expression of the CCL20, a chemokine responsible for Th17 cell recruitment. We propose placental OPG as a crucial molecule for the recognized beneficial effect of late pregnancy on MS and its potential utility for the development of new and more effective therapeutic approaches.

Characteristics of Cerebral Sinus Venous Thrombosis Patients Presenting with Intracerebral Hemorrhage

Patients with cerebral venous sinus thrombosis (CVST) occasionally present with intracerebral hemorrhage (ICH). In this study, we aimed to identify predictors for ICH in CVST patients. Prospective CVST databases from three academic centers were retrospectively analyzed. CVST patients with and without ICH upon presentation were compared. Among the 404 included patients (mean age 41.8 years, 33% male), 74 (18.3%) had an ICH. The patients with ICH were older (45 ± 20.6 vs. 41.1 ± 18 years, p = 0.045), and were more often pregnant or postpartum women (15% vs. 6%, p = 0.011), or chronically hypertensive (15% vs. 5%, p = 0.001). The ICH patients had higher rates of seizures (60% vs. 15%, p < 0.001), and focal neurological deficits (53% vs. 23%, p < 0.001). The ICH group had lower rates of excellent outcome measured by 90-day mRS 0 (56.7% vs. 80.3%, p < 0.001) and higher rates of 90-day mortality (8% vs. 3%, p = 0.041). Radiological variables associated with ICH included superior sagittal sinus (SSS) thrombosis (63% vs. 36%), isolated cortical vein thrombosis (38% vs. 8%), and presence of venous infarction (34% vs. 7%) (p < 0.001 for all). Upon multivariate analysis, chronic hypertension (OR 3.7, p = 0.027), being either pregnant or postpartum (OR 4.3, p = 0.006), isolated cortical thrombosis (OR 3.5, p = 0.007), and SSS involvement (OR 3.4, p < 0.001) were independently associated with ICH upon admission. In conclusion, among CVST patients, the following present higher for ICH: pregnant or postpartum women, and individuals with chronic hypertension, cortical vein, or SSS involvement.

Acute Intracranial Hypertension During Pregnancy: Special Considerations and Management Adjustments

Pregnancy is associated with a number of pathophysiological changes (including modification of vascular resistance, increased vascular permeability, and coagulative disorders) that can lead to specific (eclampsia, preeclampsia) or not specific (intracranial hemorrhage) neurological complications. In addition to these disorders, pregnancy can affect numerous preexisting neurologic conditions, including epilepsy, brain tumors, and intracerebral bleeding from cerebral aneurysm or arteriovenous malformations. Intracranial complications related to pregnancy can expose patients to a high risk of intracranial hypertension (IHT). Unfortunately, at present, the therapeutic measures that are generally adopted for the control of elevated intracranial pressure (ICP) in the general population have not been examined in pregnant patients, and their efficacy and safety for the mother and the fetus is still unknown. In addition, no specific guidelines for the application of the staircase approach, including escalating treatments with increasing intensity of level, for the management of IHT exist for this population. Although some of basic measures can be considered safe even in pregnant patients (management of stable hemodynamic and respiratory function, optimization of systemic physiology), some other interventions, such as hyperventilation, osmotic therapy, hypothermia, barbiturates, and decompressive craniectomy, can lead to specific concerns for the safety of both mother and fetus. The aim of this review is to summarize the neurological pathophysiological changes occurring during pregnancy and explore the effects of the possible therapeutic interventions applied to the general population for the management of IHT during pregnancy, taking into consideration ethical and clinical concerns as well as the decision for the timing of treatment and delivery.

Long-term association of pregnancy and maternal brain structure: the Rotterdam Study

The peripartum period is the highest risk interval for the onset or exacerbation of psychiatric illness in women’s lives. Notably, pregnancy and childbirth have been associated with short-term structural and functional changes in the maternal human brain. Yet the long-term effects of pregnancy on maternal brain structure remain unknown. We investigated a large population-based cohort to examine the association between parity and brain structure. In total, 2,835 women (mean age 65.2 years; all free from dementia, stroke, and cortical brain infarcts) from the Rotterdam Study underwent magnetic resonance imaging (1.5 T) between 2005 and 2015. Associations of parity with global and lobar brain tissue volumes, white matter microstructure, and markers of vascular brain disease were examined using regression models. We found that parity was associated with a larger global gray matter volume (β = 0.14, 95% CI = 0.09–0.19), a finding that persisted following adjustment for sociodemographic factors. A non-significant dose-dependent relationship was observed between a higher number of childbirths and larger gray matter volume. The gray matter volume association with parity was globally proportional across lobes. No associations were found regarding white matter volume or integrity, nor with markers of cerebral small vessel disease. The current findings suggest that pregnancy and childbirth are associated with robust long-term changes in brain structure involving a larger global gray matter volume that persists for decades. Future studies are warranted to further investigate the mechanism and physiological relevance of these differences in brain morphology.

The pathophysiologic, diagnostic, and therapeutic aspects of posterior reversible encephalopathy syndrome during pregnancy

Posterior reversible encephalopathy syndrome (PRES) is a neurological condition with a wide range of symptoms, including visual disturbances, headache, vomiting, seizures, and altered consciousness. This review describes the pathophysiology of PRES, as well as the clinical, diagnostic, and therapeutic intervention during pregnancy. The gold standard for diagnosis of PRES is Magnetic Resonance Imaging (MRI), helping to differentiate it from other similar conditions. The aim of this paper is to review the principal aspects of PRES, general care, blood pressure control, and seizures prevention while avoiding potential injuries to the mother and fetus in the event of pregnancy. We concluded that PRES can be effectively treated and reversed if prompt diagnostic action is made, and adequate care is initiated.

Sexual dimorphism in the cerebrovascular network: Brain MRI shows lower arterial density in women

BACKGROUND AND PURPOSE

Accumulating evidence suggests that there is a sexual dimorphism in brain health, with women exhibiting greater disability following strokes of comparable size and having a higher prevalence of cognitive impairment later in life. Despite the critical implication of the cerebrovascular architecture in brain perfusion and brain health, it remains unclear whether structural differences in vessel density exist across the sexes.

METHODS

In this study, we used high-density MRI imaging to characterize the intracerebral arterial and venous density of 28 (14 women) sex-matched healthy young volunteers in vivo. Using an in-house vessel segmentation algorithm, we quantified and compared these vascular features across the cortical and subcortical deep gray matter, white matter, and periventricular white matter.

RESULTS

We found that, on average, women have reduced intracerebral arterial density in comparison to men (F 2.34 ± 0.48%, M 2.67 ± 0.39%; p<.05). This difference was most pronounced in the subcortical deep gray matter (F 1.78 ± 0.53%, M 2.38 ± 0.82%; p<.05) and periventricular white matter (F 0.68 ± 0.15%, M 1.14 ± 0.33%; p<.0005), indicating a potential sex-specific vulnerability to hypoperfusion in areas critical to core cerebral functions. In contrast, venous density did not exhibit a significant difference between sexes.

CONCLUSIONS

While this research remains exploratory, it raises important pathophysiological considerations for brain health, adverse cerebrovascular events, and dementia across the sexes. Our findings also highlight the need to take into account sex differences when investigating cerebral characteristics in humans.

Prenatal exercise and cardiovascular health (PEACH) study: impact of acute and chronic exercise on cerebrovascular hemodynamics and dynamic cerebral autoregulation

We performed a randomised controlled trial measuring dynamic cerebral autoregulation (dCA) using a sit-to-stand maneuver before (SS1) and following (SS2) an acute exercise test at 16-20 weeks gestation (trimester 2; TM2) and then again at 34-37 weeks gestation (third trimester; TM3). Following the first assessment, women were randomised into exercise training or control (standard care) groups; women in the exercise training group were prescribed moderate intensity aerobic exercise for 25-40 minutes on 3-4 days per week for 14±1weeks. Resting seated mean blood velocity in the middle cerebral artery (MCAv_mean) was lower in TM3 compared to TM2 but not impacted by exercise training intervention. dCA was not impacted by gestational age, or exercise training during SS1. During SS2, dCA was altered such that there were greater absolute and relative decreases in mean arterial blood pressure (MAP) and MCAv_mean, but this was not impacted by the intervention. There was also no difference in the relationship between the decrease in MCAv_mean compared to the decrease in MAP (%/%), or the onset of the regulatory response with respect to acute exercise, gestational age, or intervention; however, rate of regulation was faster in women in the exercise group following acute exercise (interaction effect, p=0.048). These data highlight the resilience of the cerebral circulation in that dCA was well maintained or improved in healthy pregnant women between TM2 and TM3. However, future work addressing the impact of acute and chronic exercise on dCA in women who are at risk for cardiovascular complications during pregnancy is needed.

Interleukin-17 induces hypertension but does not impair cerebrovascular function in pregnant rats

Preeclampsia affects 5-8% of pregnancies and is characterized by hypertension, placental ischemia, neurological impairment, and an increase in circulating inflammatory cytokines, including Interleukin-17 (IL17). While placental ischemia has also been shown to impair cerebrovascular function, it is not known which placental-associated factor(s) drive this effect. The purpose of this study was to examine the effects of IL17 on cerebrovascular function during pregnancy. To achieve this goal, pregnant rats were infused with either IL17 (150 pg/day, 5 days, osmotic minipump), or vehicle (saline/0.7% BSA osmotic minipump) starting at gestational day (GD) 14. On GD 19, the cerebral blood flow (CBF) response to increases in mean arterial pressure (MAP) was measured in vivo, and myogenic constrictor responses of the middle cerebral artery (MCA) were assessed ex vivo. IL17 increased MAP but impaired CBF responses only at the highest arterial pressure measured (190 mmHg). Myogenic constrictor responses overall were mostly unaffected by IL17 infusion; however, the intraluminal pressure at which peak myogenic tone was generated was lower in the IL17 infused group (120 vs 165 mm Hg), suggesting maximal tone is exerted at lower intraluminal pressures in IL17-treated pregnant rats. Consistent with the lack of substantial change in overall myogenic responsiveness, there was no difference in cerebral vessel expression of putative mechanosensitive protein βENaC, but a tendency towards a decrease in ASIC2 (p = 0.067) in IL17 rats. This study suggests that infusion of IL17 independent of other placental ischemia-associated factors is insufficient to recapitulate the features of impaired cerebrovascular function during placental ischemia. Further studies to examine of the role of other pro-inflammatory cytokines, individually or a combination, are necessary to determine mechanisms of cerebral vascular dysfunction during preeclampsia.

Sexual differences in mitochondrial and related proteins in rat cerebral microvessels: A proteomic approach

Sex differences in mitochondrial numbers and function are present in large cerebral arteries, but it is unclear whether these differences extend to the microcirculation. We performed an assessment of mitochondria-related proteins in cerebral microvessels (MVs) isolated from young, male and female, Sprague-Dawley rats. MVs composed of arterioles, capillaries, and venules were isolated from the cerebrum and used to perform a 3 versus 3 quantitative, multiplexed proteomics experiment utilizing tandem mass tags (TMT), coupled with liquid chromatography/mass spectrometry (LC/MS). MS data and bioinformatic analyses were performed using Proteome Discoverer version 2.2 and Ingenuity Pathway Analysis. We identified a total of 1969 proteins, of which 1871 were quantified by TMT labels. Sixty-four proteins were expressed significantly (p < 0.05) higher in female samples compared with male samples. Females expressed more mitochondrial proteins involved in energy production, mitochondrial membrane structure, anti-oxidant enzyme proteins, and those involved in fatty acid oxidation. Conversely, males had higher expression levels of mitochondria-destructive proteins. Our findings reveal, for the first time, the full extent of sexual dimorphism in the mitochondrial metabolic protein profiles of MVs, which may contribute to sex-dependent cerebrovascular and neurological pathologies.

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.

Grape Seed Extract Polyphenols Improve Resistance Artery Function in Pregnant eNOS-/- Mice

Hypertension during pregnancy is a leading cause of maternal and fetal morbidity and mortality worldwide, increasing the risk of complications including preeclampsia, intracerebral hemorrhage and fetal growth restriction. Increased oxidative stress is known to contribute to poor vascular function; however, trials of antioxidant supplementation have raised concerns about fetal outcomes, including risk of low birthweight. Grape seed extract polyphenols (GSEP) have been suggested to promote cardiovascular protection, at least in part through antioxidant actions. We tested the hypothesis that administration of GSEP during pregnancy would reduce oxidative stress and improve resistance artery function with no detrimental effects on fetal growth, in an established model of maternal hypertension associated with vascular dysfunction, the endothelial NO synthase knockout (eNOS^-/-) mouse. Pregnant C57BL/6J (WT) and eNOS^-/- mice received either GSEP (200 mg/kg/day) or drinking water, between gestational (GD) day 10.5 and GD18.5. At GD17.5, maternal systolic blood pressure (SBP) was measured; at GD18.5, maternal malondialdehyde (MDA) concentrations, vascular function of aortic, mesenteric, uterine and posterior cerebral arteries was assessed, and fetal outcome evaluated. GSEP reduced maternal SBP (P < 0.01) and plasma MDA concentrations (P < 0.01) in eNOS^-/- mice. Whilst there was no effect of GSEP on vascular reactivity of aortas, GSEP improved endothelial-dependent relaxation in mesenteric and uterine arteries of eNOS^-/- mice (P < 0.05 and P < 0.001, respectively) and normalized lumen diameters of pressurized posterior cerebral arteries in eNOS^-/- mice (P < 0.001). Supplementation with GSEP had no effect in WT mice and did not affect fetal outcomes in either genotype. Our data suggest that GSEP improve resistance artery function, potentially through antioxidant actions, and provide a basis to further investigate these beneficial effects including in the prevention of intracerebral hemorrhage. Maternal supplementation with GSEP may be a safe intervention to improve outcomes in pregnancies associated with hypertension and vascular dysfunction.

Immediate postpartum management of patients with severe hypertensive disorders of pregnancy: pathophysiology guiding practice

Developing clinically-focused evidence and experience-based approaches to improve maternity care is a national priority. Safety and quality collaborative initiatives related to management of hypertensive disorders of pregnancy are vital in the implementation of improved care. We reviewed the obstetric literature to construct a concise summary of the core pathophysiologic issues, practice principles and clinical interventions which are foundational for physicians providing immediate postpartum care for patients with severe pregnancy-related hypertension (including those with eclampsia, HELLP syndrome, and superimposed preeclampsia inclusive of those with gestational hypertension that develop severe range blood pressures). While based largely upon the American College of Obstetrics and Gynecology (ACOG) Hypertension Task Force Guidelines released in 2013 as well as updated 2018 guidelines set forth by ACOG for hypertensive disorders of pregnancy, this summary goes beyond the basic safety bundles for hypertension management and lays a pathophysiologic foundation for the immediate postpartum care of patients with severe hypertensive disorders of pregnancy.

CBF regulation in hypertension and Alzheimer's disease

PURPOSE

To review the recent developments on the effect of chronic high mean arterial blood pressure (MAP) on cerebral blood flow (CBF) autoregulation and supporting the notion that CBF autoregulation impairment has connection with chronic cerebral diseases. Method: A narrative review of all the relevant papers known to the authors was conducted. Results: Our understanding of the connection between cerebral perfusion impairment and chronic high MAP and cerebral disease is rapidly evolving, from cerebral perfusion impairment being the result of cerebral diseases to being the cause of cerebral diseases. We now better understand the intertwined impact of hypertension and Alzheimer's disease (AD) on cerebrovascular sensory elements and recognize cerebrovascular elements that are more vulnerable to these diseases. Conclusion: We conclude with the suggestion that the sensory elements pathology plays important roles in intertwined mechanisms of chronic high MAP and AD that impact cerebral perfusion.

Resistance to the sympathoexcitatory effects of insulin and leptin in late pregnant rats

KEY POINTS

Pregnancy increases sympathetic nerve activity (SNA), although the mechanisms responsible for this remain unknown. We tested whether insulin or leptin, two sympathoexcitatory hormones increased during pregnancy, contribute to this. Transport of insulin across the blood-brain barrier in some brain regions, and into the cerebrospinal fluid (CSF), was increased, although brain insulin degradation was also increased. As a result, brain and CSF insulin levels were not different between pregnant and non-pregnant rats. The sympathoexcitatory responses to insulin and leptin were abolished in pregnant rats. Blockade of arcuate nucleus insulin receptors did not lower SNA in pregnant or non-pregnant rats. Collectively, these data suggest that pregnancy renders the brain resistant to the sympathoexcitatory effects of insulin and leptin, and that these hormones do not mediate pregnancy-induced sympathoexcitation. Increased muscle SNA stimulates glucose uptake. Therefore, during pregnancy, peripheral insulin resistance coupled with blunted insulin- and leptin-induced sympathoexcitation ensures adequate delivery of glucose to the fetus.

ABSTRACT

Pregnancy increases basal sympathetic nerve activity (SNA), although the mechanism responsible for this remains unknown. Insulin and leptin are two sympathoexcitatory hormones that increase during pregnancy, yet, pregnancy impairs central insulin- and leptin-induced signalling. Therefore, to test whether insulin or leptin contribute to basal sympathoexcitation or, instead, whether pregnancy induces resistance to the sympathoexcitatory effects of insulin and leptin, we investigated α-chloralose anaesthetized late pregnant rats, which exhibited increases in lumbar SNA (LSNA), splanchnic SNA and heart rate (HR) compared to non-pregnant animals. In pregnant rats, transport of insulin into cerebrospinal fluid and across the blood-brain barrier in some brain regions increased, although brain insulin degradation was also increased; brain and cerebrospinal fluid insulin levels were not different between pregnant and non-pregnant rats. Although i.c.v. insulin increased LSNA and HR and baroreflex control of LSNA and HR in non-pregnant rats, these effects were abolished in pregnant rats. In parallel, pregnancy completely prevented the actions of leptin with respect to increasing lumbar, splanchnic and renal SNA, as well as baroreflex control of SNA. Blockade of insulin receptors (with S961) in the arcuate nucleus, the site of action of insulin, did not decrease LSNA in pregnant rats, despite blocking the effects of exogenous insulin. Thus, pregnancy is associated with central resistance to insulin and leptin, and these hormones are not responsible for the increased basal SNA of pregnancy. Because increases in LSNA to skeletal muscle stimulates glucose uptake, blunted insulin- and leptin-induced sympathoexcitation reinforces systemic insulin resistance, thereby increasing the delivery of glucose to the fetus.

Neurovascular disorders in pregnancy: A review

While rare, neurovascular disorders that occur in pregnant or postpartum women are associated with high morbidity and mortality, thus necessitating prompt identification and treatment. The most common symptoms include headache, focal neurological features, and seizures. Factors such as pregnancy-related hypercoagulability and hemodynamic changes put women at risk for neurovascular disorders in the third trimester and early postpartum period. The biggest risk factors for stroke in pregnancy are hypertension and the preeclampsia/eclampsia spectrum. This review outlines the diagnosis and treatment of pregnant and postpartum women with ischemic and hemorrhagic stroke, cerebral venous sinus thrombosis, posterior reversible encephalopathy syndrome, and reversible cerebral vasoconstriction syndrome. Trial registration: Not applicable.

Aplastic or Twig-Like Middle Cerebral Artery Presenting with Intracerebral Hemorrhage During Pregnancy: Report of Two Cases

Background

An aplastic or twig-like middle cerebral artery (Ap/T-MCA) is a rare congenital anomaly that can present with both ischemic and hemorrhagic stroke. The etiology of this pathology has remained unclear. Here, we report 2 cases of intracerebral hemorrhage (ICH) owing to an Ap/T-MCA in pregnant patients.

Case Description

In both patients, cerebral angiography revealed a steno-occlusive lesion and an abnormal arterial network on the unilateral middle cerebral artery. One patient was treated conservatively for a putaminal hemorrhage, and a cesarean section was performed uneventfully 6 months after onset of the ICH. The other patient underwent a craniotomy for evacuation of the lobar hemorrhage. Subsequently, a cesarean section was performed uneventfully. Both patients gradually recovered without significant disabilities.

Conclusions

An Ap/T-MCA is a rare congenital anomaly and is a potential cause of ICH for pregnant patients. A cesarean section is a useful option for pregnant patients with this condition.

Cytotoxicity, genotoxicity, transplacental transfer and tissue disposition in pregnant rats mediated by nanoparticles: the case of magnetic core mesoporous silica nanoparticles

Whether in the cosmetic or as therapeutic, the use of nanoparticles has been increasing and taking on global proportion. However, there are few studies about the physical potential of long-term use or use in special conditions such as chronic, AIDS, pregnant women and other special health circumstances. In this context, the study of the mutagenicity and the transplacental passage represents an important and reliable model for the primary evaluation of potential health risks, especially maternal and child health. In this study we performed mutagenicity, cytotoxic and transplacental evaluation of magnetic core mesoporous silica nanoparticles, radiolabeled with ^99mTc for determination of toxicogenic and embryonic/fetuses potential risk in animal model. Magnetic core mesoporous silica nanoparticles were produced and characterized by obtaining nanoparticles with a size of (58.9 ± 8.1 nm) in spherical shape and with intact magnetic core. The 99 m Tc radiolabeling process demonstrated high efficacy and stability in 98% yield over a period of 8 hours of stability. Mutagenicity assays were performed using Salmonella enteric serovar Typhimurium standard strains TA98, TA100 and TA102. Cytotoxicity assays were performed using WST-1. The transplacental evaluation assays were performed using the in vivo model with rats in two periods: embryonic and fetal stage. The results of both analyzes corroborate that the nanoparticles can i) generate DNA damage; ii) generate cytotoxic potential and iii) cross the transplantation barrier in both stages and bioaccumulates in both embryos and fetuses. The results suggest that complementary evaluations should be conducted in order to attest safety, efficacy and quality of nanoparticles before unrestricted approval of their use.

Developmental Maturation and Alpha-1 Adrenergic Receptors-Mediated Gene Expression Changes in Ovine Middle Cerebral Arteries

The Alpha Adrenergic Signaling Pathway is one of the chief regulators of cerebrovascular tone and cerebral blood flow (CBF), mediating its effects in the arteries through alpha1-adrenergic receptors (Alpha1AR). In the ovine middle cerebral artery (MCA), with development from a fetus to an adult, others and we have shown that Alpha1AR play a key role in contractile responses, vascular development, remodeling, and angiogenesis. Importantly, Alpha1AR play a significant role in CBF autoregulation, which is incompletely developed in a premature fetus as compared to a near-term fetus. However, the mechanistic pathways are not completely known. Thus, we tested the hypothesis that as a function of maturation and in response to Alpha1AR stimulation there is a differential gene expression in the ovine MCA. We conducted microarray analysis on transcripts from MCAs of premature fetuses (96-day), near-term fetuses (145-day), newborn lambs, and non-pregnant adult sheep (2-year) following stimulation of Alpha1AR with phenylephrine (a specific agonist). We observed several genes which belonged to pro-inflammatory and vascular development/angiogenesis pathway significantly altered in all of the four age groups. We also observed age-specific changes in gene expression–mediated by Alpha1AR stimulation in the different developmental age groups. These findings imply complex regulatory mechanisms of cerebrovascular development.

Management of Obstructive Hydrocephalus in Pregnant Patient

De novo obstructive hydrocephalus is a rare event during pregnancy. There are only case reports presented in literature. We aimed to discuss the pathophysiological basis and management options with an exemplary case presentation and review of the current literature. A 28-year-old G2P1 patient presented to our clinic with headache, vomiting, and deteriorated vision at the 8^th week of gestation. She had no history of central nervous system infection or trauma. A brain magnetic resonance imaging was obtained. There was hydrocephalus due to cerebral aqueduct stenosis (Evan's index of 58%). She was managed conservatively with bed rest and diuretics; however, she got no relief. A ventriculoperitoneal shunt was inserted at the 13^th week of gestation. At the 38^th week, she had cesarean section (C/S) due to previous history of C/S in the first pregnancy and present cord entanglement of the fetus. C/S was conducted under epidural anesthesia after conforming she had no increased intra cranial pressure findings. Delivery was uneventful with a healthy newborn. Obstructive hydrocephalus is a very rare complication during pregnancy. Hydrocephalus becomes obvious and necessitates treatment, before the third trimester of pregnancy. Timely diagnosis, especially differentiation from preeclampsia, is a life-saving step. If no complication happens during intervention for hydrocephalus, spontaneous vaginal delivery is a safe way of delivery for both mother's and newborn's well-being. C/S should be saved for obstetrical indications and can be conducted under epidural anesthesia if intracranial pressure is kept under control. Interdisciplinary approach of neurosurgeons and anesthesiologists is pivotal for delicate care of the patient and the baby.

Cerebrovascular Hemodynamics in Women

Sex and gender, as biological and social factors, significantly influence health outcomes. Among the biological factors, sex differences in vascular physiology may be one specific mechanism contributing to the observed differences in clinical presentation, response to treatment, and clinical outcomes in several vascular disorders. This review focuses on the cerebrovascular bed and summarizes the existing literature on sex differences in cerebrovascular hemodynamics to highlight the knowledge deficit that exists in this domain. The available evidence is used to generate mechanistically plausible and testable hypotheses to underscore the unmet need in understanding sex-specific mechanisms as targets for more effective therapeutic and preventive strategies.

Assessment of maternal cerebral blood flow velocity by transcranial Doppler ultrasound before delivery and in the early postpartum period

OBJECTIVE

This prospective observational study aimed to identify the effects of labor on cerebral hemodynamics by measuring the middle cerebral artery (MCA) blood flow velocity by transcranial Doppler ultrasound (TCD), and the related factors just before delivery and within the 24 h after delivery.

METHODS

The study included 35 healthy pregnant women with a gestational age of >37 weeks who were in labor and a control group including healthy, age-matched, nonpregnant women (n = 24). Demographic characteristics and significant clinical information of pregnant women were recorded. The MCA blood flow velocity was assessed by TCD just before and within 24 h after delivery. The parameters assessed by TCD were mean cerebral blood flow velocity (MCBFV), peak systolic velocity (PSV), pulsatility index (PI), resistance index (RI), and systolic/diastolic ratio.

RESULTS

There was no significant difference between the pregnant and nonpregnant women regarding age (27 ± 5 years versus 28 ± 7 years; p = .751). The MCBFV, PSV, PI, and RI showed a significant increase within the 24 h after delivery as compared with those before delivery. Comparison of the pregnant women with the control group in terms of the values of all parameters related to the MCA blood flow velocity revealed that the values that were significantly low before delivery reached to the level of the control group after delivery Conclusion: The findings of this study demonstrated that the blood flow velocity of the MCA decreased during the late pregnancy period and increased in the early postpartum period to the level similar to that of the nonpregnant group.

Role of Mitochondria in Cerebral Vascular Function: Energy Production, Cellular Protection, and Regulation of Vascular Tone

Mitochondria not only produce energy in the form of ATP to support the activities of cells comprising the neurovascular unit, but mitochondrial events, such as depolarization and/or ROS release, also initiate signaling events which protect the endothelium and neurons against lethal stresses via pre-/postconditioning as well as promote changes in cerebral vascular tone. Mitochondrial depolarization in vascular smooth muscle (VSM), via pharmacological activation of the ATP-dependent potassium channels on the inner mitochondrial membrane (mitoKATP channels), leads to vasorelaxation through generation of calcium sparks by the sarcoplasmic reticulum and subsequent downstream signaling mechanisms. Increased release of ROS by mitochondria has similar effects. Relaxation of VSM can also be indirectly achieved via actions of nitric oxide (NO) and other vasoactive agents produced by endothelium, perivascular and parenchymal nerves, and astroglia following mitochondrial activation. Additionally, NO production following mitochondrial activation is involved in neuronal preconditioning. Cerebral arteries from female rats have greater mitochondrial mass and respiration and enhanced cerebral arterial dilation to mitochondrial activators. Preexisting chronic conditions such as insulin resistance and/or diabetes impair mitoKATP channel relaxation of cerebral arteries and preconditioning. Surprisingly, mitoKATP channel function after transient ischemia appears to be retained in the endothelium of large cerebral arteries despite generalized cerebral vascular dysfunction. Thus, mitochondrial mechanisms may represent the elusive signaling link between metabolic rate and blood flow as well as mediators of vascular change according to physiological status. Mitochondrial mechanisms are an important, but underutilized target for improving vascular function and decreasing brain injury in stroke patients. © 2016 American Physiological Society. Compr Physiol 6:1529-1548, 2016.