Blood-brain barrier leakage years after pre-eclampsia: dynamic contrast-enhanced 7-Tesla MRI study

History of hypertensive disorders of pregnancy and risk of Alzheimer's disease and vascular dementia

The incidence of dementia, and specifically, Alzheimer's disease, is higher in women than men, even in middle age, making it possible to rule out lifespan differences between men and women as a contributing factor. Thus, it is plausible that pregnancy experience, which is unique to women, may play a contributing role. In this review, we discuss the different hypertensive disorders of pregnancy (HDP), Alzheimer's and vascular dementia, clinical, epidemiological, and preclinical studies that link a history of HDP with dementia. We also present potential mechanisms linking HDP, Alzheimer's, and vascular dementia. Several key symptoms that are shared among the disorders are presented as potential underlying mechanisms that link the adverse pregnancy disorder with the long-term postpartum neurological changes. Further, we present limitations of the existing literature, gaps, and opportunities for further research.

Associations of Metabolic Syndrome and Insulin Resistance With Attenuated Executive Function Post-Preeclampsia: A Nested Case-Control Study

OBJECTIVE

Preeclampsia contributes to maternal cognitive problems, particularly involving executive functions. These higher-order cognitive functions-including working memory, organisation of materials, and task focus-are essential for adaptive, purposeful, and goal-directed behaviour. Similar cognitive problems are observed in metabolic syndrome and insulin resistance. This study investigates whether these conditions are also associated with executive function after preeclampsia.

DESIGN

Nested case-control study.

SETTING

Maastricht University Medical Centre+, a tertiary care hospital.

POPULATION

Women 0.5 to 30 years after preeclampsia.

METHODS

The Behaviour Rating Inventory of Executive Function for Adults provided a measure of executive function performance. The National Cholesterol Education Program Adult Treatment Panel III defined metabolic syndrome. The Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) quantified insulin resistance. Participants were matched on age, postpartum time, and educational attainment. Associations of attenuated executive function with metabolic syndrome, its constituents, and insulin resistance were examined with conditional logistic regression.

MAIN OUTCOME MEASURES

Odds ratios and population attributable fractions for the associations of attenuated executive function with metabolic syndrome, its constituents, and insulin resistance.

RESULTS

In 155 matched pairs, attenuated executive function was associated with metabolic syndrome (odds ratio 4.20 (95% confidence interval 1.58-11.14)), hyperglycaemia (2.96 (1.13-7.79)), and obesity (3.86 (2.00-7.47)). Attenuated executive function related to HOMA-IR (7.26 (3.75-14.07)), and was 13% (6%-20%) attributable to metabolic syndrome and 56% (49%-67%) to insulin resistance.

CONCLUSIONS

Metabolic syndrome and insulin resistance are associated with attenuated executive function after preeclampsia. Our findings provide leads for future studies focused on improving post-preeclamptic cognitive performance.

Gestational Hypertension, Preeclampsia, and Eclampsia and Future Neurological Disorders

Importance

Gestational hypertension, preeclampsia, and eclampsia are established risk factors for stroke and dementia later in life. Whether these pregnancy complications are associated with an increased risk of new-onset neurological disorders within months to years after giving birth is not known.

Objective

To explore whether gestational hypertension, preeclampsia, and eclampsia are associated with new-onset migraine, headache, epilepsy, sleep disorder, or mental fatigue within months to years after giving birth.

Design, Setting, and Participants

In this register-based cohort study, exposures were identified in the Swedish Medical Birth Register from 2005 to 2018. Follow-up was conducted using the National Patient Register, containing diagnoses from specialized inpatient and outpatient care. Follow-up started 42 days after delivery and continued until the first event, death, emigration, or the end of the follow-up period (2019). The risk was calculated with Cox regression analysis and expressed as adjusted hazard ratio (aHR) with a 95% CI. Through the Swedish Medical Birth Register, 659 188 primiparous women with singleton pregnancies between 2005 and 2018 were identified. Women with a diagnosis of chronic hypertension (n = 4271) or a prepregnancy neurological disorder (n = 6532) were excluded. The final study population included 648 385 women. Data analyses were conducted in 2023.

Exposures

Gestational hypertension, preeclampsia, and eclampsia.

Main outcome

The primary outcome was a composite neurological outcome of migraine, headache, epilepsy, sleep disorder, or mental fatigue.

Results

The study included 648 385 women with a mean age of 28.5 (SD, 5.0) years at the time of their first pregnancy. Women with gestational hypertension (n = 11 133), preeclampsia (n = 26 797), and eclampsia (n = 625) all had an association with increased risk for a new-onset neurological disorder compared with women with normotensive pregnancies. The aHR for gestational hypertension was 1.27 (95% CI, 1.12-1.45), 1.32 (95% CI, 1.22-1.42) for preeclampsia, and 1.70 (95% CI, 1.16-2.50) for eclampsia. When exploring individual outcomes, women with eclampsia were associated with more than a 5 times increased risk of epilepsy (aHR, 5.31; 95% CI, 2.85-9.89).

Conclusion and Relevance

In this study, gestational hypertension, preeclampsia, and eclampsia were associated with an increased risk of new-onset migraine, headache, epilepsy, sleep disorder, or mental fatigue within months to years after giving birth. Guidelines recommend follow-up after delivery for women with gestational hypertension and preeclampsia for their increased risk of cardiovascular disease. At these visits, caregivers should also pay attention to persisting or new-onset of neurological symptoms, since this group of women appears to be vulnerable to developing or experiencing neurological disorders.

Maternal Microvascular Dysfunction During and After Preeclamptic Pregnancy

Preeclampsia, a pregnancy disorder characterized by de novo hypertension and maternal multisystem organ dysfunction, is the leading cause of maternal mortality worldwide and is associated with a fourfold greater risk of cardiovascular disease throughout the lifespan. Current understanding of the etiology of preeclampsia remains unclear, due in part to the varying phenotypical presentations of the disease, which has hindered the development of effective and mechanism-specific treatment or prevention strategies both during and after the affected pregnancy. These maternal sequelae of preeclampsia are symptoms of systemic vascular dysfunction in the maternal nonreproductive microvascular beds that drives the development and progression of adverse cardiovascular outcomes during preeclampsia. Despite normalization of vascular disturbances after delivery, subclinical dysfunction persists in the nonreproductive microvascular beds, contributing to an increased lifetime risk of cardiovascular and metabolic diseases and all-cause mortality. Given that women with a history of preeclampsia demonstrate vascular dysfunction despite an absence of traditional CVD risk factors, an understanding of the underlying mechanisms of microvascular dysfunction during and after preeclampsia is essential to identify potential therapeutic avenues to mitigate or reverse the development of overt disease. This article aims to provide a summary of the existing literature on the pathophysiology of maternal microvascular dysfunction during preeclampsia, the mechanisms underlying the residual dysfunction that remains after delivery, and current and potential treatments both during and after the affected pregnancy that may reduce microvascular dysfunction in these high-risk women. © 2024 American Physiological Society. Compr Physiol 14:5703-5727, 2024.

Blood-Brain Barrier Integrity Decreases With Higher Blood Pressure: A 7T DCE-MRI Study

BACKGROUND

Blood-brain barrier (BBB) integrity is presumed to be impaired in hypertension, resulting from cerebral endothelial dysfunction. Hypertension precedes various cerebrovascular diseases, such as cerebral small vessel disease, and is a risk factor for developing neurodegenerative diseases for which BBB disruption is a preceding pathophysiological process. In this cross-sectional study, we investigated the relation between hypertension, current blood pressure, and BBB leakage in human subjects.

METHODS

BBB leakage was determined in 22 patients with hypertension and 19 age- and sex-matched normotensive controls (median age [range], 65 [45-80] years; 19 men) using a sparsely time-sampled contrast-enhanced 7T magnetic resonance imaging protocol. Structural cerebral small vessel disease markers were visually rated. Multivariable regression analyses, adjusted for age, sex, cardiovascular risk factors, and cerebral small vessel disease markers, were performed to determine the relation between hypertension status, systolic and diastolic blood pressure, mean arterial pressure, drug treatment, and BBB leakage.

RESULTS

Both hypertensive and normotensive participants showed mild scores of cerebral small vessel disease. BBB leakage did not differ between hypertensive and normotensive participants; however, it was significantly higher for systolic blood pressure, diastolic blood pressure, and mean arterial pressure in the cortex, and diastolic blood pressure and mean arterial pressure in the gray matter. Effectively treated patients showed less BBB leakage than those with current hypertension.

CONCLUSIONS

BBB integrity in the total and cortical gray matter decreases with increasing blood pressure but is not related to hypertension status. These findings show that BBB disruption already occurs with increasing blood pressure, before the presence of overt cerebral tissue damage. Additionally, our results suggest that effective antihypertensive medication has a protective effect on the BBB.

REGISTRATION

URL: https://trialsearch.who.int/; Unique identifier: NL7537.

Prevalence of Scarpa's ganglion enhancement on high-resolution MRI imaging

BACKGROUND AND PURPOSE

The vestibular ganglion, or Scarpa's ganglion, is a cluster of afferent vestibular neurons within the internal auditory canal (IAC). There is minimal literature describing enhancement of this region on magnetic resonance imaging (MRI) and its correlation to clinical symptoms. Here, we sought to find the prevalence of enhancement at Scarpa's ganglion, and determine whether such enhancement correlates with demographics or clinical symptoms.

MATERIALS AND METHODS

A retrospective review was performed of consecutive patients with an MRI of the IAC between 3/1/2021 and 5/20/2021. Two neuroradiologists independently reviewed for T1 and FLAIR enhancement of the Scarpa's ganglion on post-contrast fat-saturated T1 and post-contrast FLAIR images. Discrepancies were agreed upon by consensus. Clinical variables (hearing loss, vestibular symptoms, tinnitus, and MRI indication) were gathered from a retrospective chart review.

RESULTS

Eighty-nine patients were included (51 female); the mean age was 58 (range 19-85). The most common MRI indication was hearing loss (n = 53). FLAIR enhancement was present on the right in 7 patients, on the left in 7 patients, and bilaterally in 6 patients. No enhancement was seen on post-contrast T1 images. There was no statistically significant correlation between consensus FLAIR on at least one side and age (p = .74), gender (p = .29), hearing loss (p = .32), hearing loss side (p = .39), type of hearing loss (p = .87), vestibular symptoms (p = .71), or tinnitus (p = .81).

CONCLUSIONS

Enhancement is present in the minority of patients on post-contrast FLAIR images. If seen, it should be considered an uncommon but not unexpected finding with no clinical significance.

Associations of hypertensive disorders of pregnancy with cognition, dementia, and brain structure: a Mendelian randomization study

BACKGROUND

Observational studies have found associations between hypertensive disorders of pregnancy and an increased risk of cognitive dysfunction and reduced brain volume. However, the results of observational studies may have been influenced by confounding factors. This study applied two-sample Mendelian randomization (MR) to explore the causal associations of hypertensive disorders of pregnancy with cognition, dementia, and brain structure.

METHODS

Summary data on hypertensive disorders of pregnancy and their main subtypes, cognition, dementia, and brain structure were obtained from recent European genome-wide association studies. We computed the inverse-variance weighted, MR-Egger, and weighted median MR estimates. Cochran's Q statistics and the MR-Egger intercept test were used to quantify the heterogeneity and horizontal pleiotropy of the instrumental variables.

RESULTS

Genetically predicted preeclampsia or eclampsia was inversely associated with gray matter volume [beta = -0.072; 95% confidence interval (CI) = -0.131 to -0.014; P  = 1.53 × 10 -2 ]; possibly with brain volume (beta = -0.064; 95% CI = -0.117 to -0.012; P  = 1.68 × 10 -2 ). However, the association of hypertensive pregnancy disorders or gestational hypertension with brain structure was not significant. We did not find any significant association between hypertensive disorders of pregnancy, gestational hypertension, or preeclampsia or eclampsia and cognition and dementia-related outcomes.

CONCLUSION

This study provided genetic evidence supporting an association between preeclampsia or eclampsia and reduced brain volume. This supports the view of PE as a risk factor for gray matter volume reduction.

Temporal patterns of pre- and post-natal target organ damage associated with hypertensive pregnancy: a systematic review

AIMS

Hypertensive pregnancy is associated with increased risks of developing a range of vascular disorders in later life. Understanding when hypertensive target organ damage first emerges could guide optimal timing of preventive interventions. This review identifies evidence of hypertensive target organ damage across cardiac, vascular, cerebral, and renal systems at different time points from pregnancy to postpartum.

METHODS AND RESULTS

Systematic review of Ovid/MEDLINE, EMBASE, and ClinicalTrials.gov up to and including February 2023 including review of reference lists. Identified articles underwent evaluation via a synthesis without meta-analysis using a vote-counting approach based on direction of effect, regardless of statistical significance. Risk of bias was assessed for each outcome domain, and only higher quality studies were used for final analysis. From 7644 articles, 76 studies, including data from 1 742 698 pregnancies, were identified of high quality that reported either blood pressure trajectories or target organ damage during or after a hypertensive pregnancy. Left ventricular hypertrophy, white matter lesions, proteinuria, and retinal microvasculature changes were first evident in women during a hypertensive pregnancy. Cardiac, cerebral, and retinal changes were also reported in studies performed during the early and late post-partum period despite reduction in blood pressure early postpartum. Cognitive dysfunction was first reported late postpartum.

CONCLUSION

The majority of target organ damage reported during a hypertensive pregnancy remains evident throughout the early and late post-partum period despite variation in blood pressure. Early peri-partum strategies may be required to prevent or reverse target organ damage in women who have had a hypertensive pregnancy.

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.

Attenuated cognitive functioning decades after preeclampsia

BACKGROUND

Preeclampsia, a hypertensive pregnancy disorder, is a leading cause of maternal and fetal morbidity and mortality, with remote cardio- and cerebrovascular implications. After preeclampsia, women may report serious disabling cognitive complaints, especially involving executive function, but the extent and time course of these complaints are unknown.

OBJECTIVE

This study aimed to determine the impact of preeclampsia on perceived maternal cognitive functioning decades after pregnancy.

STUDY DESIGN

This study is part of a cross-sectional case-control study named Queen of Hearts (ClinicalTrials.gov Identifier: NCT02347540), a collaboration study of 5 tertiary referral centers within the Netherlands investigating long-term effects of preeclampsia. Eligible participants were female patients aged ≥18 years after preeclampsia and after normotensive pregnancy between 6 months and 30 years after their first (complicated) pregnancy. Preeclampsia was defined as new-onset hypertension after 20 weeks of gestation along with proteinuria, fetal growth restriction, or other maternal organ dysfunction. Women with a history of hypertension, autoimmune disease, or kidney disease before their first pregnancy were excluded. Attenuation of higher-order cognitive functions, that is, executive function, was measured with the Behavior Rating Inventory of Executive Function for Adults. Crude and covariate-adjusted absolute and relative risks of clinical attenuation over time after (complicated) pregnancy were determined with moderated logistic and log-binomial regression.

RESULTS

This study included 1036 women with a history of preeclampsia and 527 women with normotensive pregnancies. Regarding overall executive function, 23.2% (95% confidence interval, 19.0-28.1) of women experienced clinically relevant attenuation after preeclampsia, as opposed to 2.2% (95% confidence interval, 0.8-6.0) of controls immediately after childbirth (adjusted relative risk, 9.20 [95% confidence interval, 3.33-25.38]). Group differences diminished yet remained statistically significant (P < .05) at least 19 years postpartum. Regardless of history of preeclampsia, women with lower educational attainment, mood or anxiety disorders, or obesity were especially at risk. Neither severity of preeclampsia, multiple gestation, method of delivery, preterm birth, nor perinatal death was related to overall executive function.

CONCLUSION

After preeclampsia, women were 9 times more likely to experience clinical attenuation of higher-order cognitive functions as opposed to after normotensive pregnancy. Despite overall steady improvement, elevated risks persisted over decades after childbirth.

Cerebral volume is unaffected after pre-eclampsia

OBJECTIVES

Pre-eclampsia has been associated with cardiovascular, cerebrovascular and/or psychological complaints. Signs of altered brain morphology and more white-matter hyperintensities (WMHs) during and shortly after pre-eclampsia have been observed in some, but not all, studies. We compared volumes of cerebral structures and the number of WMHs between formerly pre-eclamptic women and those with normotensive gestational history and assessed the effect of age on brain volumes.

METHODS

Structural 7-Tesla magnetic resonance imaging of the brain was performed in 59 formerly pre-eclamptic women (aged 37 ± 6 years, 0.5-16 years postpartum) and 20 women with a history of normotensive pregnancy (aged 39 ± 5 years, 1-18 years postpartum). Fazekas scores were obtained to assess WMH load. Volumes of the whole brain, gray and white matter, brain lobes, and ventricular and pericortical cerebrospinal fluid (CSF) spaces were calculated after semiautomatic segmentation. Group differences were analyzed using ANCOVA and Bayes factors. Results were adjusted for age, educational attainment, presence of current hypertension and total intracranial volume. The effect of age on cerebral volumes was analyzed using linear regression analysis.

RESULTS

No changes in global and local brain volumes were observed between formerly pre-eclamptic and control women. Also, no difference in WMH load was observed. Independent of pre-eclamptic history, gray-matter volume significantly decreased with age, while ventricular and pericortical CSF space volumes significantly increased with age.

CONCLUSIONS

Volumetric changes of the cerebrum are age-related but are independent of pre-eclamptic history in the first two decades after childbirth. No evidence of greater WMH load after pre-eclampsia was found. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Preeclampsia and its relationship to pathological brain aging

The development of preeclampsia during pregnancy may have long-term effects on brain aging in women. Associations between preeclampsia and vascular dementia have been established, however the connection between preeclampsia and Alzheimer's disease has not been as thoroughly explored. Both preeclampsia and Alzheimer's disease have been associated with misfolded amyloid beta proteins and inflammation; due to these similarities, in this minireview, we examined the potential links between a history of preeclampsia and the development of dementia. We also discussed how hypertensive disorders of pregnancy may relate to both normal brain aging and dementia to highlight the need for additional research regarding the long-term cognitive effects of preeclampsia on the brain.