Hormones and the blood-brain barrier

2015 ◽  
Vol 21 (3) ◽  
Author(s):  
Richard Hampl ◽  
Marie Bičíková ◽  
Lucie Sosvorová
Keyword(s):  
Endothelial Cells ◽  
Tight Junctions ◽  
Blood Brain Barrier ◽  
Energy Homeostasis ◽  
Brain Structures ◽  
Brain Barrier ◽  
Selection Function ◽  
Membrane Structures ◽  
Blood Brain ◽  
The Brain

AbstractHormones exert many actions in the brain, and brain cells are also hormonally active. To reach their targets in brain structures, hormones must overcome the blood-brain barrier (BBB). The BBB is a unique device selecting desired/undesired molecules to reach or leave the brain, and it is composed of endothelial cells forming the brain vasculature. These cells differ from other endothelial cells in their almost impermeable tight junctions and in possessing several membrane structures such as receptors, transporters, and metabolically active molecules, ensuring their selection function. The main ways how compounds pass through the BBB are briefly outlined in this review. The main part concerns the transport of major classes of hormones: steroids, including neurosteroids, thyroid hormones, insulin, and other peptide hormones regulating energy homeostasis, growth hormone, and also various cytokines. Peptide transporters mediating the saturable transport of individual classes of hormones are reviewed. The last paragraph provides examples of how hormones affect the permeability and function of the BBB either at the level of tight junctions or by various transporters.

scholarly journals Modulating the Blood-Brain Barrier by Light Stimulation of Molecular-Targeted Nanoparticles

2020 ◽  
Author(s):  
Xiaoqing Li ◽  
Vamsidhara Vemireddy ◽  
Qi Cai ◽  
Hejian Xiong ◽  
Peiyuan Kang ◽  
...  
Keyword(s):  
Tight Junction ◽  
Tight Junctions ◽  
Blood Brain Barrier ◽  
Therapeutic Interventions ◽  
Brain Barrier ◽  
Light Stimulation ◽  
Targeted Nanoparticles ◽  
Blood Brain ◽  
The Brain ◽  
Stimulation Of

AbstractThe blood-brain barrier (BBB) tightly regulates the entry of molecules into the brain by tight junctions that seals the paracellular space and receptor-mediated transcytosis. It remains elusive to selectively modulate these mechanisms and to overcome BBB without significant neurotoxicity. Here we report that light stimulation of tight junction-targeted plasmonic nanoparticles selectively opens up the paracellular route to allow diffusion through the compromised tight junction and into the brain parenchyma. The BBB modulation does not impair vascular dynamics and associated neurovascular coupling, or cause significant neural injury. It further allows antibody and adeno-associated virus delivery into local brain regions. This novel method offers the first evidence of selectively modulating BBB tight junctions and opens new avenues for therapeutic interventions in the central nervous system.One Sentence SummaryGentle stimulation of molecular-targeted nanoparticles selectively opens up the paracellular pathway and allows macromolecules and gene therapy vectors into the brain.

Modulation of tight junction structure in blood-brain barrier endothelial cells. Effects of tissue culture, second messengers and cocultured astrocytes

1994 ◽  
Vol 107 (5) ◽  
pp. 1347-1357 ◽  
Author(s):  
H. Wolburg ◽  
J. Neuhaus ◽  
U. Kniesel ◽  
B. Krauss ◽  
E.M. Schmid ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Tight Junction ◽  
Tight Junctions ◽  
Blood Brain Barrier ◽  
Barrier Function ◽  
Primary Cultures ◽  
Brain Barrier ◽  
Brain Endothelial Cells ◽  
Blood Brain ◽  
Camp Levels

Tight junctions between endothelial cells of brain capillaries are the most important structural elements of the blood-brain barrier. Cultured brain endothelial cells are known to loose tight junction-dependent blood-brain barrier characteristics such as macromolecular impermeability and high electrical resistance. We have directly analyzed the structure and function of tight junctions in primary cultures of bovine brain endothelial cells using quantitative freeze-fracture electron microscopy, and ion and inulin permeability. The complexity of tight junctions, defined as the number of branch points per unit length of tight junctional strands, decreased 5 hours after culture but thereafter remained almost constant. In contrast, the association of tight junction particles with the cytoplasmic leaflet of the endothelial membrane bilayer (P-face) decreased continuously with a major drop between 16 hours and 24 hours. The complexity of tight junctions could be increased by elevation of intracellular cAMP levels while phorbol esters had the opposite effect. On the other hand, the P-face association of tight junction particles was enhanced by elevation of cAMP levels and by coculture of endothelial cells with astrocytes or exposure to astrocyte-conditioned medium. The latter effect on P-face association was induced by astrocytes but not fibroblasts. Elevation of cAMP levels together with astrocyte-conditioned medium synergistically increased transendothelial electrical resistance and decreased inulin permeability of primary cultures, thus confirming the effects on tight junction structure and barrier function. P-face association of tight junction particles in brain endothelial cells may therefore be a critical feature of blood-brain barrier function that can be specifically modulated by astrocytes and cAMP levels. Our results suggest an important functional role for the cytoplasmic anchorage of tight junction particles for brain endothelial barrier function in particular and probably paracellular permeability in general.

Anthropogenic Iron Oxide Nanoparticles Induce Damage to Brain Microvascular Endothelial Cells Forming the Blood-Brain Barrier

2021 ◽  
Author(s):  
Lorena Gárate-Vélez ◽  
Claudia Escudero-Lourdes ◽  
Daniela Salado-Leza ◽  
Armando González-Sánchez ◽  
Ildemar Alvarado-Morales ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Microvascular Endothelial Cells ◽  
Brain Microvascular Endothelial Cells ◽  
Blood Brain ◽  
Fe3o4 Nps ◽  
Microvascular Endothelial ◽  
The Brain

Background: Iron nanoparticles, mainly in magnetite phase (Fe3O4 NPs), are released to the environment in areas with high traffic density and braking frequency. Fe3O4 NPs were found in postmortem human brains and are assumed to get directly into the brain through the olfactory nerve. However, these pollution-derived NPs may also translocate from the lungs to the bloodstream and then, through the blood-brain barrier (BBB), into the brain inducing oxidative and inflammatory responses that contribute to neurodegeneration. Objective: To describe the interaction and toxicity of pollution-derived Fe3O4 NPs on primary rat brain microvascular endothelial cells (rBMECs), main constituents of in vitro BBB models. Methods: Synthetic bare Fe3O4 NPs that mimic the environmental ones (miFe3O4) were synthesized by co-precipitation and characterized using complementary techniques. The rBMECs were cultured in Transwell® plates. The NPs-cell interaction was evaluated through transmission electron microscopy and standard colorimetric in vitro assays. Results: The miFe3O4 NPs, with a mean diameter of 8.45 ± 0.14 nm, presented both magnetite and maghemite phases, and showed super-paramagnetic properties. Results suggest that miFe3O4 NPs are internalized by rBMECs through endocytosis and that they are able to cross the cells monolayer. The lowest miFe3O4 NPs concentration tested induced mid cytotoxicity in terms of 1) membrane integrity (LDH release) and 2) metabolic activity (MTS transformation). Conclusion: Pollution-derived Fe3O4 NPs may interact and cross the microvascular endothelial cells forming the BBB and cause biological damage.

scholarly journals Structural, Molecular, and Functional Alterations of the Blood-Brain Barrier during Epileptogenesis and Epilepsy: A Cause, Consequence, or Both?

2020 ◽  
Vol 21 (2) ◽  
pp. 591 ◽  
Author(s):  
Wolfgang Löscher ◽  
Alon Friedman
Keyword(s):  
Endothelial Cells ◽  
Blood Brain Barrier ◽  
Defense Mechanism ◽  
Extracellular Fluid ◽  
Cell Types ◽  
Therapeutic Interventions ◽  
Brain Barrier ◽  
Transport Systems ◽  
Blood Brain ◽  
The Brain

The blood-brain barrier (BBB) is a dynamic, highly selective barrier primarily formed by endothelial cells connected by tight junctions that separate the circulating blood from the brain extracellular fluid. The endothelial cells lining the brain microvessels are under the inductive influence of neighboring cell types, including astrocytes and pericytes. In addition to the anatomical characteristics of the BBB, various specific transport systems, enzymes and receptors regulate molecular and cellular traffic across the BBB. While the intact BBB prevents many macromolecules and immune cells from entering the brain, following epileptogenic brain insults the BBB changes its properties. Among BBB alterations, albumin extravasation and diapedesis of leucocytes from blood into brain parenchyma occur, inducing or contributing to epileptogenesis. Furthermore, seizures themselves may modulate BBB functions, permitting albumin extravasation, leading to activation of astrocytes and the innate immune system, and eventually modifications of neuronal networks. BBB alterations following seizures are not necessarily associated with enhanced drug penetration into the brain. Increased expression of multidrug efflux transporters such as P-glycoprotein likely act as a ‘second line defense’ mechanism to protect the brain from toxins. A better understanding of the complex alterations in BBB structure and function following seizures and in epilepsy may lead to novel therapeutic interventions allowing the prevention and treatment of epilepsy as well as other detrimental neuro-psychiatric sequelae of brain injury.

scholarly journals Impact of the Renin–Angiotensin System on the Endothelium in Vascular Dementia: Unresolved Issues and Future Perspectives

2020 ◽  
Vol 21 (12) ◽  
pp. 4268 ◽  
Author(s):  
Fatima Y. Noureddine ◽  
Raffaele Altara ◽  
Fan Fan ◽  
Andriy Yabluchanskiy ◽  
George W. Booz ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Vascular Dementia ◽  
Blood Brain Barrier ◽  
Renin Angiotensin System ◽  
Brain Barrier ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Blood Brain ◽  
Body Tissues ◽  
The Brain

The effects of the renin–angiotensin system (RAS) surpass the renal and cardiovascular systems to encompass other body tissues and organs, including the brain. Angiotensin II (Ang II), the most potent mediator of RAS in the brain, contributes to vascular dementia via different mechanisms, including neuronal homeostasis disruption, vascular remodeling, and endothelial dysfunction caused by increased inflammation and oxidative stress. Other RAS components of emerging significance at the level of the blood–brain barrier include angiotensin-converting enzyme 2 (ACE2), Ang(1–7), and the AT2, Mas, and AT4 receptors. The various angiotensin hormones perform complex actions on brain endothelial cells and pericytes through specific receptors that have either detrimental or beneficial actions. Increasing evidence indicates that the ACE2/Ang(1–7)/Mas axis constitutes a protective arm of RAS on the blood–brain barrier. This review provides an update of studies assessing the different effects of angiotensins on cerebral endothelial cells. The involved signaling pathways are presented and help highlight the potential pharmacological targets for the management of cognitive and behavioral dysfunctions associated with vascular dementia.

Benzophenone-3 Passes Through the Blood-Brain Barrier, Increases the Level of Extracellular Glutamate, and Induces Apoptotic Processes in the Hippocampus and Frontal Cortex of Rats

2019 ◽  
Vol 171 (2) ◽  
pp. 485-500 ◽  
Author(s):  
Bartosz Pomierny ◽  
Weronika Krzyżanowska ◽  
Żaneta Broniowska ◽  
Beata Strach ◽  
Beata Bystrowska ◽  
...  
Keyword(s):  
Spatial Memory ◽  
Blood Brain Barrier ◽  
Brain Structures ◽  
Glutamate Transporters ◽  
Brain Barrier ◽  
Short Term ◽  
Extracellular Glutamate ◽  
Blood Brain ◽  
The Impact ◽  
The Brain

Abstract Benzophenone-3 is the most commonly used UV filter. It is well absorbed through the skin and gastrointestinal tract. Its best-known side effect is the impact on the function of sex hormones. Little is known about the influence of BP-3 on the brain. The aim of this study was to show whether BP-3 crosses the blood-brain barrier (BBB), to determine whether it induces nerve cell damage in susceptible brain structures, and to identify the mechanism of its action in the central nervous system. BP-3 was administered dermally during the prenatal period and adulthood to rats. BP-3 effect on short-term and spatial memory was determined by novel object and novel location recognition tests. BP-3 concentrations were assayed in the brain and peripheral tissues. In brain structures, selected markers of brain damage were measured. The study showed that BP-3 is absorbed through the rat skin, passes through the BBB. BP-3 raised oxidative stress and induced apoptosis in the brain. BP-3 increased the concentration of extracellular glutamate in examined brain structures and changed the expression of glutamate transporters. BP-3 had no effect on short-term memory but impaired spatial memory. The present study showed that dermal BP-3 exposure may cause damage to neurons what might be associated with the increase in the level of extracellular glutamate, most likely evoked by changes in the expression of GLT-1 and xCT glutamate transporters. Thus, exposure to BP-3 may be one of the causes that increase the risk of developing neurodegenerative diseases.

scholarly journals The Dual Role of Microglia in Blood-Brain Barrier Dysfunction after Stroke

2020 ◽  
Vol 18 (12) ◽  
pp. 1237-1249 ◽  
Author(s):  
Ruiqing Kang ◽  
Marcin Gamdzyk ◽  
Cameron Lenahan ◽  
Jiping Tang ◽  
Sheng Tan ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Blood Brain Barrier ◽  
Vital Role ◽  
Dual Role ◽  
Brain Barrier ◽  
Barrier Dysfunction ◽  
Blood Brain ◽  
M2 Microglia ◽  
The Brain

It is well-known that stroke is one of the leading causes of death and disability all over the world. After a stroke, the blood-brain barrier subsequently breaks down. The BBB consists of endothelial cells surrounded by astrocytes. Microglia, considered the long-living resident immune cells of the brain, play a vital role in BBB function. M1 microglia worsen BBB disruption, while M2 microglia assist in repairing BBB damage. Microglia can also directly interact with endothelial cells and affect BBB permeability. In this review, we are going to discuss the mechanisms responsible for the dual role of microglia in BBB dysfunction after stroke.

scholarly journals Human pluripotent stem cell-derived brain pericyte-like cells induce blood-brain barrier properties

2018 ◽  
Author(s):  
Matthew J. Stebbins ◽  
Benjamin D. Gastfriend ◽  
Scott G. Canfield ◽  
Ming-Song Lee ◽  
Drew Richards ◽  
...  
Keyword(s):  
Stem Cells ◽  
Endothelial Cells ◽  
Blood Brain Barrier ◽  
Pluripotent Stem Cells ◽  
Neurovascular Unit ◽  
Human Pluripotent Stem Cells ◽  
Brain Barrier ◽  
Blood Brain ◽  
Brain Pericytes ◽  
The Brain

ABSTRACTBrain pericytes play an important role in the formation and maintenance of the neurovascular unit (NVU), and their dysfunction has been implicated in central nervous system (CNS) disorders. While human pluripotent stem cells (hPSCs) have been used to model other components of the NVU including brain microvascular endothelial cells (BMECs), astrocytes, and neurons, cells having brain pericyte-like phenotypes have not been described. In this study, we generated neural crest stem cells (NCSCs), the embryonic precursor to forebrain pericytes, from human pluripotent stem cells (hPSCs) and subsequently differentiated NCSCs to brain pericyte-like cells. The brain pericyte-like cells expressed marker profiles that closely resembled primary human brain pericytes, and they self-assembled with endothelial cells to support vascular tube formation. Importantly, the brain pericyte-like cells induced blood-brain barrier (BBB) properties in BMECs, including barrier enhancement and reduction of transcytosis. Finally, brain pericyte-like cells were incorporated with iPSC-derived BMECs, astrocytes, and neurons to form an isogenic human NVU model that should prove useful for the study of the BBB in CNS health, disease, and therapy.

Sign in / Sign up

Export Citation Format

Share Document