Blood-based cerebral biomarkers in preeclampsia: Plasma concentrations of NfL, tau, S100B and NSE during pregnancy in women who later develop preeclampsia - A nested case control study

Pregnancy as a window of opportunity for dementia prevention: a narrative review

Dementia is a debilitating condition with a disproportionate impact on women. While sex differences in longevity contribute to the disparity, the role of the female sex as a biological variable in disease progression is not yet fully elucidated. Metabolic dysfunctions are drivers of dementia etiology, and cardiometabolic diseases are among the most influential modifiable risk factors. Pregnancy is a time of enhanced vulnerability for metabolic disorders. Many dementia risk factors, such as hypertension or blood glucose dysregulation, often emerge for the first time in pregnancy. While such cardiometabolic complications in pregnancy pose a risk to the health trajectory of a woman, increasing her odds of developing type 2 diabetes or chronic hypertension, it is not fully understood how this relates to her risk for dementia. Furthermore, structural and functional changes in the maternal brain have been reported during pregnancy suggesting it is a time of neuroplasticity for the mother. Therefore, pregnancy may be a window of opportunity to optimize metabolic health and support the maternal brain. Healthy dietary patterns are known to reduce the risk of cardiometabolic diseases and have been linked to dementia prevention, yet interventions targeting cognitive function in late life have largely been unsuccessful. Earlier interventions are needed to address the underlying metabolic dysfunctions and potentially reduce the risk of dementia, and pregnancy offers an ideal opportunity to intervene. This review discusses current evidence regarding maternal brain health and the potential window of opportunity in pregnancy to use diet to address neurological health disparities for women.

AI-based preeclampsia detection and prediction with electrocardiogram data

Introduction

More than 76,000 women die yearly from preeclampsia and hypertensive disorders of pregnancy. Early diagnosis and management of preeclampsia can improve outcomes for both mother and baby. In this study, we developed artificial intelligence models to detect and predict preeclampsia from electrocardiograms (ECGs) in point-of-care settings.

Methods

Ten-second 12-lead ECG data was obtained from two large health care settings: University of Tennessee Health Science Center (UTHSC) and Atrium Health Wake Forest Baptist (AHWFB). UTHSC data was split into 80% training and 20% holdout data. The model used a modified ResNet convolutional neural network, taking one-dimensional raw ECG signals comprising 12 channels as an input, to predict risk of preeclampsia. Sub-analyses were performed to assess the predictive accuracy for preeclampsia prediction within 30, 60, or 90 days before diagnosis.

Results

The UTHSC cohort included 904 ECGs from 759 females (78.8% African American) with a mean ± sd age of 27.3 ± 5.0 years. The AHWFB cohort included 817 ECGs from 141 females (45.4 African American) with a mean ± sd age of 27.4 ± 5.9 years. The cross-validated ECG-AI model yielded an AUC (95% CI) of 0.85 (0.77-0.93) on UTHSC holdout data, and an AUC (95% CI) of 0.81 (0.77-0.84) on AHWFB data. The sub-analysis of different time windows before preeclampsia prediction resulted in AUCs (95% CI) of 0.92 (0.84-1.00), 0.89 (0.81-0.98) and 0.90 (0.81-0.98) when tested on ECGs 30 days, 60 days and 90 days, respectively, before diagnosis. When assessed on early onset preeclampsia (preeclampsia diagnosed at <34 weeks of pregnancy), the model's AUC (95% CI) was 0.98 (0.89-1.00).

Discussion

We conclude that preeclampsia can be identified with high accuracy via application of AI models to ECG data.

Cis P-tau is a central circulating and placental etiologic driver and therapeutic target of preeclampsia

Preeclampsia (PE) is the leading cause of maternal and fetal mortality globally and may trigger dementia later in life in mothers and their offspring. However, the etiological drivers remain elusive. Cis P-tau is an early etiological driver and blood biomarker in pre-clinical Alzheimer's and after vascular or traumatic brain injury, which can be targeted by stereo-specific antibody, with clinical trials ongoing. Here we find significant cis P-tau in the placenta and serum of PE patients, and in primary human trophoblasts exposed to hypoxia or sera from PE patients due to Pin1 inactivation. Depletion of cis P-tau from PE patient sera by the antibody prevents their ability to disrupt trophoblast invasion and endovascular activity and to cause the PE-like pathological and clinical features in pregnant humanized tau mice. Our studies uncover that cis P-tau is a central circulating etiological driver and its stereo-specific antibody is valuable for early PE diagnosis and treatment.

Translational research updates in female health anesthesiology: a narrative review

Background and Objective

Females represent 49.6% of the global population and constitute a significant proportion of surgical patients and hospital admissions. Little is known about the bi-directional effects of sex and anesthetics or the impact of anesthetic interventions on long-term female health outcomes. Sex differences in pain pathways can influence pain experience and treatment effectiveness. The impact of anesthetic management on the recurrence of breast cancer is poorly understood, as are the long-term consequences of cardiovascular disease and safe and effective treatments in pregnancy. This review aims to outline recent advances in translational science in female health anesthesiology research and highlight critical research opportunities in pain, cancer outcomes, and cardiovascular disorders.

Methods

We searched PubMed and summarized relevant articles published in English between December 2021 and June 2022.

Key Content and Findings

Studies reveal sex differences in pain pathways and highlight the importance of sex as a biological variable in experimental designs and translational medicine. Sex differences have also been observed in side effects attributed to opioid analgesics. We summarize some of the neural circuits that might underlie these differences. In the perioperative setting, specific anesthetics are implicated in metastatic seeding potential and acute and chronic pain outcomes, suggesting the importance of anesthetic selection in comprehensive care during oncologic surgery. In the peridelivery setting, preeclampsia, a cardiovascular disorder of pregnancy, affects maternal outcomes; however, biomarkers can risk-stratify females at risk for preeclampsia and hold promise for identifying the risk of adverse neurological and other health outcomes.

Conclusions

Research that builds diagnostic and predictive tools in pain and cardiovascular disease will help anesthesiologists minimize sex-related risks and side effects associated with anesthetics and peri-hospital treatments. Sex-specific anesthesia care will improve outcomes, as will the provision of practical information to patients and clinicians about the effectiveness of therapies and behavioral interventions. However, more research studies and specific analytic plans are needed to continue addressing sex-based outcomes in anesthesiology.

Correlation between cognitive assessment scores and circulating cerebral biomarkers in women with pre-eclampsia and eclampsia

OBJECTIVES

The cerebral injury biomarkers neurofilament light chain (NfL) and tau and the glial activation biomarker glial fibrillary acidic protein (GFAP) may reflect neurological injury in pre-eclampsia. We assessed if there was a correlation between cognitive function assessment scores and plasma concentrations of these biomarkers in pre-eclampsia.

STUDY DESIGN

Women with eclampsia, pre-eclampsia and normotensive pregnancies from the South African PROVE biobank were included. Blood samples were taken at inclusion. The Montreal Cognitive Assessment was performed after delivery at the time of discharge. The correlation between cognitive assessment scores and plasma concentrations of cerebral biomarkers was analysed using Spearman correlation adjusted for time from eclamptic seizure.

MAIN OUTCOME MEASURES

We included 49 women with eclampsia, 16 women with pre-eclampsia complicated by pulmonary oedema, 22 women with pre-eclampsia without pulmonary oedema, HELLP or neurological complications and 18 women with normotensive pregnancies.

RESULTS

There was a correlation between impaired cognitive function and increased plasma concentrations of NfL in women with eclampsia and women with pre-eclampsia and pulmonary oedema (r = -0.37, p = 0.009 and r = -0.56, p = 0.025 respectively). No correlation between impaired cognitive function and NfL in pre-eclampsia cases without pulmonary oedema, HELLP or neurological complications or normotensive pregnancies was found. No correlation with cognitive impairment was found in any groups for tau or GFAP.

CONCLUSIONS

We found a correlation between impaired cognitive function assessment and plasma NfL concentrations in women with eclampsia and pre-eclampsia complicated by pulmonary oedema. These findings suggest that acute neuroaxonal injury may cause or contribute to cognitive impairment in these women.

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.

Preeclampsia and the Kidney: Pathophysiology and Clinical Implications

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

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.

Head-to-Head Comparison of Different Blood Collecting Tubes for Quantification of Alzheimer’s Disease Biomarkers in Plasma

To examine whether the type of blood collection tubes affects the quantification of plasma biomarkers for Alzheimer’s disease analyzed with a single-molecule array (Simoa), we recruited a healthy cohort (n = 34, 11 males, mean age = 28.7 ± 7.55) and collected plasma in the following tubes: dipotassium ethylenediaminetetraacetic acid (K2-EDTA), heparin lithium (Li-Hep), and heparin sodium (Na-Hep). Plasma tau, phosphorylated tau 181 (p-tau181), amyloid β (1–40) (Aβ40), and amyloid β (1–42) (Aβ42) were quantified using Simoa. We compared the value of plasma analytes, as well as the effects of sex on the measurements. We found that plasma collected in Li-Hep and Na-Hep tubes yielded significantly higher tau and p-tau181 levels compared to plasma collected in K2-EDTA tubes from the same person, but there was no difference in the measured values of the Aβ40, Aβ42, and Aβ42/40 ratio. Therefore, the type of blood collecting tubes should be considered when planning studies that measure plasma tau.

Virus-Induced Membrane Fusion in Neurodegenerative Disorders

A growing body of epidemiological and research data has associated neurotropic viruses with accelerated brain aging and increased risk of neurodegenerative disorders. Many viruses replicate optimally in senescent cells, as they offer a hospitable microenvironment with persistently elevated cytosolic calcium, abundant intracellular iron, and low interferon type I. As cell-cell fusion is a major driver of cellular senescence, many viruses have developed the ability to promote this phenotype by forming syncytia. Cell-cell fusion is associated with immunosuppression mediated by phosphatidylserine externalization that enable viruses to evade host defenses. In hosts, virus-induced immune dysfunction and premature cellular senescence may predispose to neurodegenerative disorders. This concept is supported by novel studies that found postinfectious cognitive dysfunction in several viral illnesses, including human immunodeficiency virus-1, herpes simplex virus-1, and SARS-CoV-2. Virus-induced pathological syncytia may provide a unified framework for conceptualizing neuronal cell cycle reentry, aneuploidy, somatic mosaicism, viral spreading of pathological Tau and elimination of viable synapses and neurons by neurotoxic astrocytes and microglia. In this narrative review, we take a closer look at cell-cell fusion and vesicular merger in the pathogenesis of neurodegenerative disorders. We present a "decentralized" information processing model that conceptualizes neurodegeneration as a systemic illness, triggered by cytoskeletal pathology. We also discuss strategies for reversing cell-cell fusion, including, TMEM16F inhibitors, calcium channel blockers, senolytics, and tubulin stabilizing agents. Finally, going beyond neurodegeneration, we examine the potential benefit of harnessing fusion as a therapeutic strategy in regenerative medicine.

Cerebral biomarkers in neurologic complications of preeclampsia

BACKGROUND

There is no tool to accurately predict who is at risk of developing neurologic complications of preeclampsia, and there is no objective method to determine disease severity.

OBJECTIVE

We assessed whether plasma concentrations of the cerebral biomarkers neurofilament light, tau, and glial fibrillary acidic protein could reflect disease severity in several phenotypes of preeclampsia. Furthermore, we compared the cerebral biomarkers with the angiogenic biomarkers soluble fms-like tyrosine kinase 1, placental growth factor, and soluble endoglin.

STUDY DESIGN

In this observational study, we included women from the South African Preeclampsia Obstetric Adverse Events biobank. Plasma samples taken at diagnosis (preeclampsia cases) or admission for delivery (normotensive controls) were analyzed for concentrations of neurofilament light, tau, glial fibrillary acidic protein, placental growth factor, soluble fms-like tyrosine kinase 1, and soluble endoglin. The cerebrospinal fluid concentrations of inflammatory markers and albumin were analyzed in a subgroup of 15 women. Analyses were adjusted for gestational age, time from seizures and delivery to sampling, maternal age, and parity.

RESULTS

Compared with 28 women with normotensive pregnancies, 146 women with preeclampsia demonstrated 2.18-fold higher plasma concentrations of neurofilament light (95% confidence interval, 1.64-2.88), 2.17-fold higher tau (95% confidence interval, 1.49-3.16), and 2.77-fold higher glial fibrillary acidic protein (95% confidence interval, 2.06-3.72). Overall, 72 women with neurologic complications (eclampsia, cortical blindness, and stroke) demonstrated increased plasma concentrations of tau (2.99-fold higher; 95% confidence interval, 1.92-4.65) and glial fibrillary acidic protein (3.22-fold higher; 95% confidence interval, 2.06-5.02) compared with women with preeclampsia without pulmonary edema; hemolysis, elevated liver enzymes, and low platelet count; or neurologic complications (n=31). Moreover, angiogenic markers were higher, but to a lesser extent. Women with hemolysis, elevated liver enzymes, and low platelet count (n=20) demonstrated increased plasma concentrations of neurofilament light (1.64-fold higher; 95% confidence interval, 1.06-2.55), tau (4.44-fold higher; 95% confidence interval, 1.85-10.66), and glial fibrillary acidic protein (1.82-fold higher; 95% confidence interval, 1.32-2.50) compared with women with preeclampsia without pulmonary edema; hemolysis, elevated liver enzymes, and low platelet count; or neurologic complications. There was no difference shown in the angiogenic biomarkers. There was no difference between 23 women with preeclampsia complicated by pulmonary edema and women with preeclampsia without pulmonary edema; hemolysis, elevated liver enzymes, and low platelet count; or neurologic complications for any of the biomarkers. Plasma concentrations of tau and glial fibrillary acidic protein were increased in women with several neurologic complications compared with women with eclampsia only.

CONCLUSION

Plasma neurofilament light, glial fibrillary acidic, and tau were candidate biomarkers for the diagnosis and possibly prediction of cerebral complications of preeclampsia.

How Soluble Fms-Like Tyrosine Kinase 1 Could Contribute to Blood-Brain Barrier Dysfunction in Preeclampsia?

Preeclampsia is a pregnancy-related syndrome that courses with severe cerebrovascular complications if not properly managed. Findings from pre-clinical and clinical studies have proposed that the imbalance between pro- and anti-angiogenic factors exhibited in preeclampsia is a major component of its pathophysiology. In this regard, measurement of circulating levels of soluble tyrosine kinase-1 similar to fms (sFlt-1), a decoy receptor for vascular endothelial growth factor (VEGF), is a moderately reliable biomarker for the diagnosis of preeclampsia. However, few studies have established a mechanistic approach to determine how the high levels of sFlt-1 are responsible for the endothelial dysfunction, and even less is known about its effects at the blood-brain barrier (BBB). Since the expression pattern of VEGF receptors type 1 and 2 in brain endothelial cells differs from the observed in peripheral endothelial cells, and components of the neurovascular unit of the BBB provide paracrine secretion of VEGF, this compartmentalization of VEGF signaling could help to see in a different viewpoint the role of sFlt-1 in the development of endothelial dysfunction. In this article, we provide a hypothesis of how sFlt-1 could eventually be a protective factor for brain endothelial cells of the BBB under preeclampsia.

Cerebral Biomarkers and Blood-Brain Barrier Integrity in Preeclampsia

Cerebral complications in preeclampsia contribute substantially to maternal mortality and morbidity. There is a lack of reliable and accessible predictors for preeclampsia-related cerebral complications. In this study, plasma from women with preeclampsia (n = 28), women with normal pregnancies (n = 28) and non-pregnant women (n = 16) was analyzed for concentrations of the cerebral biomarkers neurofilament light (NfL), tau, neuron-specific enolase (NSE) and S100B. Then, an in vitro blood−brain barrier (BBB) model, based on the human cerebral microvascular endothelial cell line (hCMEC/D3), was employed to assess the effect of plasma from the three study groups. Transendothelial electrical resistance (TEER) was used as an estimation of BBB integrity. NfL and tau are proteins expressed in axons, NSE in neurons and S100B in glial cells and are used as biomarkers for neurological injury in other diseases such as dementia, traumatic brain injury and hypoxic brain injury. Plasma concentrations of NfL, tau, NSE and S100B were all higher in women with preeclampsia compared with women with normal pregnancies (8.85 vs. 5.25 ng/L, p < 0.001; 2.90 vs. 2.40 ng/L, p < 0.05; 3.50 vs. 2.37 µg/L, p < 0.001 and 0.08 vs. 0.05 µg/L, p < 0.01, respectively). Plasma concentrations of NfL were also higher in women with preeclampsia compared with non-pregnant women (p < 0.001). Higher plasma concentrations of the cerebral biomarker NfL were associated with decreased TEER (p = 0.002) in an in vitro model of the BBB, a finding which indicates that NfL could be a promising biomarker for BBB alterations in preeclampsia.

Study protocol: establishment of a multicentre pre-eclampsia database and biobank in Sweden: GO PROVE and UP MOST, a prospective cohort study

INTRODUCTION

Pre-eclampsia, a multisystem disorder in pregnancy, is one of the most common causes of maternal morbidity and mortality worldwide. However, we lack methods for objective assessment of organ function in pre-eclampsia and predictors of organ impairment during and after pre-eclampsia. The women's and their partners' experiences of pre-eclampsia have not been studied in detail. To phenotype different subtypes of the disorder is of importance for prediction, prevention, surveillance, treatment and follow-up of pre-eclampsia.The aim of this study is to set up a multicentre database and biobank for pre-eclampsia in order to contribute to a safer and more individualised treatment and care.

METHODS AND ANALYSIS

This is a multicentre cohort study. Prospectively recruited pregnant women ≥18 years, diagnosed with pre-eclampsia presenting at Sahlgrenska University Hospital, Uppsala University Hospital and at Södra Älvsborgs Hospital, Sweden, as well as normotensive controls are eligible for participation. At inclusion and at 1-year follow-up, the participants donate biosamples that are stored in a biobank and they are also asked to participate in various organ-specific evaluations. In addition, questionnaires and interviews regarding the women's and partner's experiences are distributed at follow-up.

ETHICS AND DISSEMINATION

By creating a database and biobank, we will provide the means to explore the disorder in a broader sense and allow clinical and laboratory discoveries that can be translated to clinical trials aiming at improved care of women with pre-eclampsia. Further, to evaluate experiences and the psychological impact of being affected by pre-eclampsia can improve the care of pregnant women and their partners. In case of incidental pathological findings during examinations performed, they will be handled in accordance with clinical routine. Data are stored in a secure online database. Biobank samples are identified through the women's personal identification number and pseudonymised after identification in the biobank before analysis.This study was approved by the regional ethical review board in Gothenburg on 28 December 2018 (approval number 955-18) and by the Swedish Ethical Review Authority on 27 February 2019 (approval number 2019-00309).Results from the study will be published in international peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ISRCTN13060768.

Serum Neurofilament Light: a Potential Diagnostic and Prognostic Biomarker in Obstetric Posterior Reversible Encephalopathy Syndrome

Obstetric posterior reversible encephalopathy syndrome (PRES), caused by preeclampsia (PE) or eclampsia, is a clinical imaging syndrome and a critical maternal complication, with vasogenic edema in white matter as a typical imaging characteristic. Serum neurofilament light (NFL) is a marker of neuroaxonal injury. Therefore, we performed this study to explore the diagnostic and prognostic role of NFL in obstetric PRES. We used stored serum samples and clinical data obtained from 2148 PE or eclampsia patients from the Guangzhou Medical Centre for Critical Pregnant Women from January 2015 to January 2020. The serum NFL concentration was measured by Simoa assay. Patients without complete data and MRI examinations were excluded. All patients were grouped into the PRES and non-PRES groups based on the PRES diagnostic criteria. In total, 222 patients met the inclusion criteria and were grouped into the PRES (n = 123) and non-PRES (n = 99) groups. The NFL level was significantly higher in the PRES group than in the non-PRES group (p < 0.0001). The discriminatory accuracy of diagnostic panels (headaches + NFL, NFL) in receiver operating characteristic curve analysis (area under the curve) was 0.9338 and 0.7664. Importantly, the NFL level was significantly correlated with edema severity (Spearman's correlation, p < 0.0001), and a poorer pregnancy outcome was observed in the PRES group. In conclusion, an increased NFL level can add predictive value for diagnosing obstetric PRES, and its level is associated with both clinical severity and pregnancy outcome, suggesting that NFL could serve as a diagnostic and prognostic biomarker for obstetric PRES.

PROVE-Pre-Eclampsia Obstetric Adverse Events: Establishment of a Biobank and Database for Pre-Eclampsia

Pre-eclampsia is a leading cause of maternal and perinatal morbidity and mortality. The burden of disease lies mainly in low-middle income countries. The aim of this project is to establish a pre-eclampsia biobank in South Africa to facilitate research in the field of pre-eclampsia with a focus on phenotyping severe disease.The approach of our biobank is to collect biological specimens, detailed clinical data, tests, and biophysical examinations, including magnetic resonance imaging (MRI) of the brain, MRI of the heart, transcranial Doppler, echocardiography, and cognitive function tests.Women diagnosed with pre-eclampsia and normotensive controls are enrolled in the biobank at admission to Tygerberg University Hospital (Cape Town, South Africa). Biological samples and clinical data are collected at inclusion/delivery and during the hospital stay. Special investigations as per above are performed in a subset of women. After two months, women are followed up by telephonic interviews. This project aims to establish a biobank and database for severe organ complications of pre-eclampsia in a low-middle income country where the incidence of pre-eclampsia with organ complications is high. The study integrates different methods to investigate pre-eclampsia, focusing on improved understanding of pathophysiology, prediction of organ complications, and potentially future drug evaluation and discovery.

Ultrasensitive assays for detection of plasma tau and phosphorylated tau 181 in Alzheimer's disease: a systematic review and meta-analysis

A lack of convenient and reliable biomarkers for diagnosis and prognosis is a common challenge for neurodegenerative diseases such as Alzheimer's disease (AD). Recent advancement in ultrasensitive protein assays has allowed the quantification of tau and phosphorylated tau proteins in peripheral plasma. Here we identified 66 eligible studies reporting quantification of plasma tau and phosphorylated tau 181 (ptau181) using four ultrasensitive methods. Meta-analysis of these studies confirmed that the AD patients had significantly higher plasma tau and ptau181 levels compared with controls, and that the plasma tau and ptau181 could predict AD with high-accuracy area under curve of the Receiver Operating Characteristic. Therefore, plasma tau and plasma ptau181 can be considered as biomarkers for AD diagnosis.

Signs of neuroaxonal injury in preeclampsia-A case control study

BACKGROUND

Cerebral injury is a common cause of maternal mortality due to preeclampsia and is challenging to predict and diagnose. In addition, there are associations between previous preeclampsia and stroke, dementia and epilepsy later in life. The cerebral biomarkers S100B, neuron specific enolase, (NSE), tau protein and neurofilament light chain (NfL) have proven useful as predictors and diagnostic tools in other neurological disorders. This case-control study sought to determine whether cerebral biomarkers were increased in cerebrospinal fluid (CSF) as a marker of cerebral origin and potential cerebral injury in preeclampsia and if concentrations in CSF correlated to concentrations in plasma.

METHODS

CSF and blood at delivery from 15 women with preeclampsia and 15 women with normal pregnancies were analysed for the cerebral biomarkers S100B, NSE, tau protein and NfL by Simoa and ELISA based methods. MRI brain was performed after delivery and for women with preeclampsia also at six months postpartum.

RESULTS

Women with preeclampsia demonstrated increased CSF- and plasma concentrations of NfL and these concentrations correlated to each other. CSF concentrations of NSE and tau were decreased in preeclampsia and there were no differences in plasma concentrations of NSE and tau between groups. For S100B, serum concentrations in preeclampsia were increased but there was no difference in CSF concentrations of S100B between women with preeclampsia and normal pregnancy.

CONCLUSION

NfL emerges as a promising circulating cerebral biomarker in preeclampsia and increased CSF concentrations point to a neuroaxonal injury in preeclampsia, even in the absence of clinically evident neurological complications.

Association of Cerebrospinal Fluid S100B Protein with Core Biomarkers and Cognitive Deficits in Prodromal and Mild Alzheimer's Disease

BACKGROUND

Increased expression of the astroglial Ca2+-binding protein S100B has been observed in various neurodegenerative diseases and also seems to play a role in the unfolding of pathophysiological events at early stages of Alzheimer's disease (AD).

OBJECTIVE

To examine the association of cerebrospinal fluid (CSF) levels of S100B with 1) established CSF core biomarkers total tau (tau), hyperphosphorylated tau (p-tau), and amyloid β1-42 (Aβ1-42) as well as neuron-specific enolase (NSE) CSF levels and 2) cognition in early AD and mild cognitive impairment (MCI) due to AD (MCI-AD).

METHODS

Retrospective study assessing 49 pooled charts of Memory Clinic and inpatients diagnosed with AD (N = 26) and MCI-AD (N = 23) according to the National Institute of Aging and Alzheimer's Disease Association (NIA-AA) criteria. Neuropsychological testing was performed with the Consortium to Establish a Registry for AD (CERAD)-Plus battery.

RESULTS

CSF levels of S100B correlated with NSE, but not the other CSF parameters. Stepwise multiple linear regression, adjusted for age, sex, and educational level, revealed that only increased CSF S100B was independently associated with lower CERAD-Plus total and Mini-Mental Status Examination scores together with poorer performance in wordlist learning (delayed recall and overall performance). We found no independent associations with other CSF biomarkers or cognitive domains.

CONCLUSION

Our data suggest that CSF S100B may have a diagnostic value particularly at early stages of AD reflecting the significance of neuroinflammatory/astroglial processes. Thus, CSF S100B may complement the established array of available AD biomarkers to improve early stage diagnosis.

Cerebrospinal beta-amyloid peptides(1-40) and (1-42) in severe preeclampsia and HELLP syndrome - a pilot study

During pregnancy, substantial alterations in cerebral plasticity, vascular remodeling and neuronal growth occur in the maternal brain. We investigated whether concentrations of selected neurodiagnostic biomarkers in the cerebrospinal fluid of women with preeclampsia/HELLP syndrome differ from those in healthy controls using enzyme-linked immunosorbent assay technique. We found that tau protein concentrations (p = 0.016) and phospho-tau/tau ratio (p < 0.001) in cerebrospinal fluid were significantly lower in 39 preeclamptic women compared to 44 healthy controls during third trimester of pregnancy. Beta-amyloid(1-40)/(1-42) ratio was significantly higher in HELLP syndrome than in severe preeclampsia (8.49 + 2.73 vs. 4.71 + 1.65; p = 0.007). We conclude that beta-amyloid(1-40)/(1-42) ratio in cerebrospinal fluid can discriminate severe preeclampsia and HELLP syndrome. High beta-amyloid peptide and low tau protein concentrations are associated with impaired development of the materno-feto-placental unit and correlate with placental dysfunction.

Single-molecule measurements in microwells for clinical applications

The ability to detect and analyze proteins, nucleic acids, and other biomolecules is critical for clinical diagnostics and for understanding the underlying mechanisms of disease. Current detection methods in clinical and research laboratories rely upon bulk measurement techniques such as immunoassays, polymerase chain reaction, and mass spectrometry to detect these biomarkers. However, many potentially useful protein or nucleic acid biomarkers in blood, saliva, or other biofluids exist at concentrations well below the detection limits of current methods, necessitating the development of more sensitive technologies. Single-molecule measurements are poised to address this challenge, vastly improving sensitivity for detecting low abundance biomarkers and rare events within a population. Microwell arrays have emerged as a powerful tool for single-molecule measurements, enabling ultrasensitive detection of disease-relevant biomolecules in easily accessible biofluids. This review discusses the development, fundamentals, and clinical applications of microwell-based single-molecule methods, as well as challenges and future directions for translating these methods to the clinic.

Impact of parturition on maternal cardiovascular and neuronal integrity in a high risk cohort - a prospective cohort study

Background

To better understand the profound multisystem changes in maternal physiology triggered by parturition, in particular in the underexplored neuronal system, by deploying a panel of pre- vs post-delivery maternal serum biomarkers, most notably the neuronal cytoskeleton constituent neurofilament light chain (NfL). This promising fluid biomarker is not only increasingly applied to investigate disease progression in numerous brain diseases, particularly in proteopathies, but also in detection of traumatic brain injury or monitoring neuroaxonal injury after ischemic stroke.

Methods

The study was nested within a prospective cohort study of pregnant women at risk of developing preeclampsia at the University Hospital of Basel. Paired ante- and postpartum levels of progesterone, soluble fms-like tyrosine kinase-1 (sFlt-1), placental growth factor (PlGF), mid-regional pro-atrial natriuretic peptide (MR-proANP), copeptin (CT-proAVP), and NfL were measured in 56 women with complete clinical data.

Results

Placental delivery significantly decreased all placental markers: progesterone 4.5-fold, PlGF 2.2-fold, and sFlt-1 1.7-fold. Copeptin and MR-proANP increased slightly (1.4- and 1.2-fold, respectively). Unexpectedly, NfL levels (median [interquartile range]) increased significantly post-partum: 49.4 (34.7–77.8) vs 27.7 (16.7–31.4) pg/ml (p < 0.0001). Antepartum NfL was the sole independent predictor of NfL peri-partum change; mode of delivery, duration of labor, clinical characteristics and other biomarkers were all unrelated. Antepartum NfL levels were themselves independently predicted only by maternal age.

Conclusions

Parturition per se increases maternal serum NfL levels, suggesting a possible impact of parturition on maternal neuronal integrity.

Assessment of blood-brain barrier integrity and neuroinflammation in preeclampsia

BACKGROUND

Although blood-brain barrier integrity is intact under normal pregnancy conditions, animal studies suggest that blood-brain barrier impairment occurs in preeclampsia. Yet, human data are limited, and the integrity of the blood-brain barrier has not been assessed in women with preeclampsia.

OBJECTIVE

We sought to test the hypothesis that the integrity of the blood-brain barrier is impaired and that neuroinflammation is increased in women with preeclampsia.

STUDY DESIGN

We performed an observational case-control study in pregnant women >24 weeks gestation who underwent spinal anesthesia for elective cesarean delivery or combined spinal epidural analgesia for labor. Cases were women with preeclampsia, and control subjects were women with either healthy pregnancy, chronic hypertension, or gestational hypertension. Paired samples of blood, urine, and cerebrospinal fluid were collected from each subject before delivery. We measured albumin, C5a, C5b-9, tumor necrosis factor-α, and interleukin-6 concentrations in plasma and cerebrospinal fluid, and albumin, C5a, and C5b-9 concentrations in urine, using colorimetric or enzyme-linked immunosorbent assays. The ratio of albumin in cerebrospinal fluid to plasma (Qalb) was used as a surrogate for maternal blood-brain barrier integrity. Cerebrospinal fluid concentrations of C5a, C5b-9, tumor necrosis factor-α, and interleukin-6 were used as surrogate markers of neuroinflammation. Differences in Qalb and cerebrospinal fluid protein concentrations between groups were assessed by nonparametric test of medians.

RESULTS

Forty-eight subjects were enrolled, which included 16 cases with preeclampsia, 16 control subjects with healthy pregnancy, and 16 control subjects with either chronic or gestational hypertension. Qalb values were not increased in preeclampsia cases compared with healthy or hypertensive control subjects (Qalb median, 3.5 [interquartile range, 2.9-5.1] vs 3.9 [interquartile range, 3.0-4.8] vs 3.9 [interquartile range, 3.0-4.8]; P=.78]. Moreover, Qalb values were not increased in the subset of women with preeclampsia with severe features (n=8) compared with those without severe features (n=8; Qalb median, 3.5 [interquartile range, 3.3-4.9] vs 3.7 [interquartile range, 2.3-5.5]; P=.62]. Cerebrospinal fluid concentrations of C5a, C5b-9, tumor necrosis factor-α and interleukin-6 were not increased in cases of preeclampsia, compared with control subjects with either healthy pregnancy, chronic hypertension, or gestational hypertension (P>.05, all comparisons). In contrast to the negative findings in cerebrospinal fluid, plasma concentrations of both C5b-9 and interleukin-6 and urine concentrations of C5a and C5b-9 were increased in cases of preeclampsia.

CONCLUSION

Through measurements of albumin, complement proteins, and cytokines in paired samples of blood and cerebrospinal fluid at the time of delivery, we found no evidence of blood-brain barrier impairment or neuroinflammation in preeclampsia. Larger studies that will investigate a wider range of proteins are suggested to validate our findings.

Investigating Maternal Brain Alterations in Preeclampsia: the Need for a Multidisciplinary Effort

PURPOSE OF REVIEW

To provide insight into the mechanisms underlying cerebral pathophysiology and to highlight possible methods for evaluation, screening, and surveillance of cerebral complications in preeclampsia.

RECENT FINDINGS

The pathophysiology of eclampsia remains enigmatic. Animal studies show that the cerebral circulation in pregnancy and preeclampsia might be affected with increased permeability over the blood-brain barrier and altered cerebral blood flow due to impaired cerebral autoregulation. The increased blood pressure cannot be the only underlying cause of eclampsia and cerebral edema, since some cases of eclampsia arise without simultaneous hypertension. Findings from animal studies need to be confirmed in human tissues. Evaluation of brain alterations in preeclampsia and eclampsia is challenging and demands a multidisciplinary collaboration, since no single method can accurately and fully describe how preeclampsia affects the brain. Cerebral complications of preeclampsia are significant factors in maternal morbidity and mortality worldwide. No single method can accurately describe the full picture of how preeclampsia affects the brain vasculature and parenchyma. We recommend an international and multidisciplinary effort not only to overcome the issue of limited sample availability but also to optimize the quality of research.

Drug Transport at the Brain and Endothelial Dysfunction in Preeclampsia: Implications and Perspectives

Transport of drugs across biological barriers has been a subject of study for decades. The discovery and characterization of proteins that confer the barrier properties of endothelia and epithelia, including tight junction proteins and membrane transporters belonging to the ATP-binding cassette (ABC) and Solute Carrier (SLC) families, represented a significant step forward into understanding the mechanisms that govern drug disposition. Subsequently, numerous studies, including both pre-clinical approaches and clinical investigations, have been carried out to determine the influence of physiological and pathological states on drug disposition. Importantly, there has been increasing interest in gaining a better understanding of drug disposition during pregnancy, since epidemiological and clinical studies have demonstrated that the use of medications by pregnant women is significant and this condition embodies a series of significant anatomical and physiological modifications, particularly at excretory organs and barrier sites (e.g., placenta, breast) expressing transporter proteins which influence pharmacokinetics. Currently, most of the research in this field has focused on the expression profiling of transporter proteins in trophoblasts and endothelial cells of the placenta, regulation of drug-resistance mechanisms in disease states and pharmacokinetic studies. However, little attention has been placed on the influence that the cerebrovascular dysfunction present in pregnancy-related disorders, such as preeclampsia, might exert on drug disposition in the mother’s brain. This issue is particularly important since recent findings have demonstrated that preeclamptic women suffer from long-term alterations in the integrity of the blood-brain barrier (BBB). In this review we aim to analyze the available evidence regarding the influence of pregnancy on the expression of transporters and TJ proteins in brain endothelial cells, as well the mechanisms that govern the pathophysiological alterations in the BBB of women who experience preeclampsia. Future research efforts should be focused not only on achieving a better understanding of the influence of preeclampsia-associated endothelial dysfunction on drug disposition, but also in optimizing the pharmacological treatments of women suffering pregnancy-related disorders, its comorbidities and to develop new therapies aiming to restore the integrity of the BBB.