scholarly journals THE PATHWAY BETWEEN HYALOID BLOOD AND RETINAL NEURONS IN THE TOAD

1967 ◽  
Vol 34 (2) ◽  
pp. 617-626 ◽  
Author(s):  
Arnaldo Lasansky
Keyword(s):  
Central Nervous System ◽  
Endothelial Cells ◽  
Nervous System ◽  
Horseradish Peroxidase ◽  
Trypan Blue ◽  
Vitreous Humor ◽  
Retinal Neurons ◽  
Intercellular Spaces ◽  
Systemic Injection ◽  
Inner Surface

The hyaloid vessels form a capillary network on the inner surface of the retina. These capillaries are embedded in the vitreous humor, and they lack a glial investment. The intercellular spaces of the retina communicate with the ocular cavity, as can be evidenced by following the penetration of tracer substances. Hence, there is an extracellular diffusion pathway between hyaloid capillaries and retinal neurons, without interposition of glial cells. Trypan blue and ferrocyanide were not detected within the vitreous humor nor the retina after systemic injection. To this extent, at least, the hyaloid capillaries functionally resemble central nervous system capillaries. Intravascular injections of horseradish peroxidase established the absence of vesicular transfer across the endothelium of the hyaloid capillaries. In addition, quintuple-layered junctions between endothelial cells prevented the intercellular passage of the enzyme. It is likely, therefore, that the only pathway across the endothelium of the hyaloid capillaries is through the plasmalemma of the endothelial cells.

scholarly journals Delivery of Therapeutic Agents to the Central Nervous System and the Promise of Extracellular Vesicles

Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 492
Author(s):  
Charlotte A. René ◽  
Robin J. Parks
Keyword(s):  
Central Nervous System ◽  
Endothelial Cells ◽  
Nervous System ◽  
Blood Brain Barrier ◽  
Extracellular Vesicles ◽  
Therapeutic Agents ◽  
Target Cells ◽  
Significant Barrier ◽  
The Central Nervous System ◽  
Delivery Vehicles

The central nervous system (CNS) is surrounded by the blood–brain barrier (BBB), a semipermeable border of endothelial cells that prevents pathogens, solutes and most molecules from non-selectively crossing into the CNS. Thus, the BBB acts to protect the CNS from potentially deleterious insults. Unfortunately, the BBB also frequently presents a significant barrier to therapies, impeding passage of drugs and biologicals to target cells within the CNS. This review provides an overview of different approaches to deliver therapeutics across the BBB, with an emphasis in extracellular vesicles as delivery vehicles to the CNS.

scholarly journals A genome-wide view of the de-differentiation of central nervous system endothelial cells in culture

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Mark F Sabbagh ◽  
Jeremy Nathans
Keyword(s):  
Central Nervous System ◽  
Endothelial Cells ◽  
Nervous System ◽  
In Vitro Culture ◽  
Vascular Endothelial Cells ◽  
Beta Catenin ◽  
A Genome ◽  
Accessible Chromatin

Vascular endothelial cells (ECs) derived from the central nervous system (CNS) variably lose their unique barrier properties during in vitro culture, hindering the development of robust assays for blood-brain barrier (BBB) function, including drug permeability and extrusion assays. In previous work (Sabbagh et al., 2018) we characterized transcriptional and accessible chromatin landscapes of acutely isolated mouse CNS ECs. In this report, we compare transcriptional and accessible chromatin landscapes of acutely isolated mouse CNS ECs versus mouse CNS ECs in short-term in vitro culture. We observe that standard culture conditions are associated with a rapid and selective loss of BBB transcripts and chromatin features, as well as a greatly reduced level of beta-catenin signaling. Interestingly, forced expression of a stabilized derivative of beta-catenin, which in vivo leads to a partial conversion of non-BBB CNS ECs to a BBB-like state, has little or no effect on gene expression or chromatin accessibility in vitro.

scholarly journals Endothelial cells are a replicative niche for entry of Toxoplasma gondii to the central nervous system

2016 ◽  
Vol 1 (3) ◽  
Author(s):  
Christoph Konradt ◽  
Norikiyo Ueno ◽  
David A. Christian ◽  
Jonathan H. Delong ◽  
Gretchen Harms Pritchard ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Endothelial Cells ◽  
Nervous System ◽  
Toxoplasma Gondii ◽  
The Central Nervous System

Ultracytochemical Studies of Capillary Endothelial Cells in the Rat Central Nervous System

1984 ◽  
Vol 118 (4) ◽  
pp. 243-248 ◽  
Author(s):  
Kenichirou Inomata ◽  
Takafumi Yoshioka ◽  
Fumio Nasu ◽  
Hiroshi Mayahara
Keyword(s):  
Central Nervous System ◽  
Endothelial Cells ◽  
Nervous System ◽  
Capillary Endothelial Cells

scholarly journals Encephalitic Alphaviruses Exploit Caveola-Mediated Transcytosis at the Blood-Brain Barrier for Central Nervous System Entry

mBio ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Hamid Salimi ◽  
Matthew D. Cain ◽  
Xiaoping Jiang ◽  
Robyn A. Roth ◽  
Wandy L. Beatty ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Endothelial Cells ◽  
Nervous System ◽  
Viral Replication ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Type I ◽  
Brain Endothelial Cells ◽  
Blood Brain ◽  
Deficient Mice

ABSTRACT Venezuelan and western equine encephalitis viruses (VEEV and WEEV, respectively) invade the central nervous system (CNS) early during infection, via neuronal and hematogenous routes. While viral replication mediates host shutoff, including expression of type I interferons (IFN), few studies have addressed how alphaviruses gain access to the CNS during established infection or the mechanisms of viral crossing at the blood-brain barrier (BBB). Here, we show that hematogenous dissemination of VEEV and WEEV into the CNS occurs via caveolin-1 (Cav-1)-mediated transcytosis (Cav-MT) across an intact BBB, which is impeded by IFN and inhibitors of RhoA GTPase. Use of reporter and nonreplicative strains also demonstrates that IFN signaling mediates viral restriction within cells comprising the neurovascular unit (NVU), differentially rendering brain endothelial cells, pericytes, and astrocytes permissive to viral replication. Transmission and immunoelectron microscopy revealed early events in virus internalization and Cav-1 association within brain endothelial cells. Cav-1-deficient mice exhibit diminished CNS VEEV and WEEV titers during early infection, whereas viral burdens in peripheral tissues remained unchanged. Our findings show that alphaviruses exploit Cav-MT to enter the CNS and that IFN differentially restricts this process at the BBB. IMPORTANCE VEEV, WEEV, and eastern equine encephalitis virus (EEEV) are emerging infectious diseases in the Americas, and they have caused several major outbreaks in the human and horse population during the past few decades. Shortly after infection, these viruses can infect the CNS, resulting in severe long-term neurological deficits or death. Neuroinvasion has been associated with virus entry into the CNS directly from the bloodstream; however, the underlying molecular mechanisms have remained largely unknown. Here, we demonstrate that following peripheral infection alphavirus augments vesicular formation/trafficking at the BBB and utilizes Cav-MT to cross an intact BBB, a process regulated by activators of Rho GTPases within brain endothelium. In vivo examination of early viral entry in Cav-1-deficient mice revealed significantly lower viral burdens in the brain than in similarly infected wild-type animals. These studies identify a potentially targetable pathway to limit neuroinvasion by alphaviruses.

scholarly journals The Biology of Brain Metastasis

2013 ◽  
Vol 59 (1) ◽  
pp. 180-189 ◽  
Author(s):  
Robert R Langley ◽  
Isaiah J Fidler
Keyword(s):  
Central Nervous System ◽  
Endothelial Cells ◽  
Nervous System ◽  
Brain Metastasis ◽  
Brain Metastases ◽  
Disease Progression ◽  
Microvascular Endothelial Cells ◽  
Number Of Patients ◽  
The Central Nervous System ◽  
Microvascular Endothelial

BACKGROUND It is estimated that at least 200 000 cases of brain metastases occur each year in the US, which is 10 times the number of patients diagnosed with primary brain tumors. Brain metastasis is associated with poor prognosis, neurological deterioration, diminished quality of life, and extremely short survival. Favorable interactions between tumor cells and cerebral microvascular endothelial cells encourage tumor growth in the central nervous system, while tumor cell interactions with astrocytes protect brain metastases from the cytotoxic effects of chemotherapy. CONTENT We review the pathogenesis of brain metastasis and emphasize the contributions of microvascular endothelial cells and astrocytes to disease progression and therapeutic resistance. Animal models used to study brain metastasis are also discussed. SUMMARY Brain metastasis has many unmet clinical needs. There are few clinically relevant tumor models and no targeted therapies specific for brain metastases, and the mean survival for untreated patients is 5 weeks. Improved clinical outcomes are dependent on an enhanced understanding of the metastasis-initiating population of cells and the identification of microenvironmental factors that encourage disease progression in the central nervous system.

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