Cerebral biomarkers in neurologic complications of preeclampsia

Novel peptidomimetic compounds attenuate hypoxic-ischemic brain injury in neonatal rats

Hypoxic-ischemic (HI) brain injury is a common neurological problem in neonates. The postsynaptic density protein-95 (PSD-95) is an excitatory synaptic scaffolding protein that regulates synaptic function, and represents a potential therapeutic target to attenuate HI brain injury. Syn3 and d-Syn3 are novel high affinity cyclic peptides that bind the PDZ3 domain of PSD-95. We investigated the neuroprotective efficacy of Syn3 and d-Syn3 after exposure to HI in neonatal rodents. Postnatal (P) day-7 rats were treated with Syn3 and d-Syn3 at zero, 24, and 48-h after carotid artery ligation and 90-min of 8 % oxygen. Hemispheric volume atrophy and Iba-1 positive microglia were quantified by cresyl violet and immunohistochemical staining. Treatment with Syn3 and d-Syn3 reduced tissue volume loss by 47.0 % and 41.0 % in the male plus female, and by 42.1 % and 65.0 % in the male groups, respectively. Syn3 reduced tissue loss by 52.3 % in females. D-Syn3 reduced Iba-1 positive microglia/DAPI ratios in the pooled group, males, and females. Syn3 effects were observed in the pooled group and females. Changes in Iba-1 positive microglia/DAPI cellular ratios correlated directly with reduced hemispheric volume loss, suggesting that Syn3 and d-Syn3 provide neuroprotection in part by their effects on Iba-1 positive microglia. The pathogenic cis phosphorylated Thr231 in Tau (cis P-tau) is a marker of neuronal injury. Cis P-tau was induced in cortical cells of the placebo-treated pooled group, males and females after HI, and reduced by treatment with d-Syn3. Therefore, treatment with these peptidomimetic agents exert neuroprotective effects after exposure of neonatal subjects to HI related brain injury.

The role of the Pin1-cis P-tau axis in the development and treatment of vascular contribution to cognitive impairment and dementia and preeclampsia

Tauopathies are neurodegenerative diseases characterized by deposits of abnormal Tau protein in the brain. Conventional tauopathies are often defined by a limited number of Tau epitopes, notably neurofibrillary tangles, but emerging evidence suggests structural heterogeneity among tauopathies. The prolyl isomerase Pin1 isomerizes cis P-tau to inhibit the development of oligomers, tangles and neurodegeneration in multiple neurodegenerative diseases such as Alzheimer's disease, traumatic brain injury, vascular contribution to cognitive impairment and dementia (VCID) and preeclampsia (PE). Thus, cis P-tau has emerged as an early etiological driver, blood marker and therapeutic target for multiple neurodegenerative diseases, with clinical trials ongoing. The discovery of cis P-tau and other tau pathologies in VCID and PE calls attention for simplistic classification of tauopathy in neurodegenerative diseases. These recent advances have revealed the exciting novel role of the Pin1-cis P-tau axis in the development and treatment of vascular contribution to cognitive impairment and dementia and preeclampsia.

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.

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.

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 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.