scholarly journals Amphotericin B Penetrates into the Central Nervous System through Focal Disruption of the Blood-Brain Barrier in Experimental Hematogenous Candida Meningoencephalitis

2019 ◽  
Vol 63 (12) ◽  
Author(s):  
Vidmantas Petraitis ◽  
Ruta Petraitiene ◽  
Jessica M. Valdez ◽  
Vasilios Pyrgos ◽  
Martin J. Lizak ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Amphotericin B ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Blue Dye ◽  
Bolus Administration ◽  
Blood Brain ◽  
Mri Scans

ABSTRACT Hematogenous Candida meningoencephalitis (HCME) is a life-threatening complication of neonates and immunocompromised children. Amphotericin B (AmB) shows poor permeation and low cerebrospinal fluid (CSF) concentrations but is effective in the treatment of HCME. In order to better understand the mechanism of CNS penetration of AmB, we hypothesized that AmB may achieve focally higher concentrations in infected CNS lesions. An in vitro blood-brain barrier (BBB) model was serially infected with Candida albicans. Liposomal AmB (LAMB) or deoxycholate AmB (DAMB) at 5 μg/ml was then provided, and the vascular and CNS compartments were sampled 4 h later. For in vivo correlation, rabbits with experimental HCME received a single dose of DAMB at 1 mg/kg of body weight or LAMB at 5 mg/kg and were euthanized after 1, 3, 6, and 24 h. Evans blue dye solution (2%, 2 ml/kg) administered intravenously (i.v.) at 1 h prior to euthanasia stained infected regions of tissue but not histologically normal areas. AmB concentrations in stained and unstained tissue regions were measured using ultraperformance liquid chromatography. For selected rabbits, magnetic resonance imaging (MRI) scans performed on days 1 to 7 postinoculation were acquired before and after i.v. bolus administration of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) at 15-min intervals through 2 h postinjection. The greatest degree of penetration of DAMB and LAMB through the in vitro BBB occurred after 24 h of exposure (P = 0.0022). In vivo the concentrations of LAMB and DAMB in brain abscesses were 4.35 ± 0.59 and 3.14 ± 0.89 times higher, respectively, than those in normal tissue (P ≤ 0.019). MRI scans demonstrated that Gd-DTPA accumulated in infected areas with a disrupted BBB. Localized BBB disruption in HCME allows high concentrations of AmB within infected tissues, despite the presence of low cerebrospinal fluid concentrations.

Prostate cancer-derived anti-GRP78 autoantibodies compromise the blood-brain barrier and accelerate atherosclerosis progression in vivo.

2019 ◽  
Vol 37 (7_suppl) ◽  
pp. 205-205
Author(s):  
Ali Al-Hashimi ◽  
Bobby Shayegan ◽  
Richard Austin ◽  
Kevin Doyoon Won
Keyword(s):  
Prostate Cancer ◽  
Blood Brain Barrier ◽  
Atherosclerotic Plaque ◽  
The Body ◽  
Brain Barrier ◽  
Blue Dye ◽  
Plaque Progression ◽  
Blood Brain

205 Background: Pathological conditions of prostate cancer (PCa) drive the translocation of the endoplasmic reticulum-resident chaperone, GRP78, to the cell surface (cs) where it acts as an antigenic protein with signaling properties. In PCa, csGRP78 drives the production of anti-GRP78 autoantibodies (AutoAbs) that engage csGRP78 and promote PCa survival/progression. New studies now demonstrate csGRP78 expression on endothelial cells (EC) that line the arterial vasculature and the blood-brain barrier (BBB) suggesting that these AutoAbs can affect other systems in the body. Based on this, we investigated how the engagement of anti-GRP78 AutoAbs to csGRP78 on EC can contribute to EC-dysfunction that can promote atherosclerosis and compromise the integrity of the BBB. Methods: Anti-GRP78 AutoAbs were purified from PCa patients (St. Joseph’s Healthcare Hamilton); human aortic EC and the ApoE -/- mouse model were used for in vitro and in vivo investigations, respectively. EC or mice were treated with anti-GRP78 AutoAbs or IgG control (60µg/mL); EC-dysfunction was investigated by measuring attachment protein expression, in vitro. In vivo evaluation was carried out by studying atherosclerotic plaque progression (immunohistochemistry; aorta); the BBB integrity was examined using the Evans Blue dye. Results: Mice injected with anti-GRP78 AutoAbs, and not human IgG, demonstrated larger atherosclerotic plaque volume and hallmarks of a leaky BBB. In terms of a mechanism, in vitro studies demonstrated that treating EC with anti-GRP78 AutoAbs resulted in activation of the NFκB pathway that led to increased expression of attachment proteins. All these effects were reversed by using a recombinant molecule that interfere with the binding of the AutoAb to csGRP78. Conclusions: We have identified anti-GRP78 AutoAb as a driver of EC-dysfunction that promote atherosclerotic plaque progression and damage to the BBB. Our results indicate that interfering with anti-GRP78 AutoAb:csGRP78 complex can reverse the pathological effects of the AutoAbs. This novel data suggests that patient-derived anti-GRP78 autoantibodies systemically drive pathologies, other than cancer, in vivo.

scholarly journals EXTH-66. NEO100 TRANSIENTLY OPENS UP THE BLOOD BRAIN BARRIER VIA TIGHT JUNCTION INHIBITION

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii101-ii102
Author(s):  
Thomas Chen ◽  
Weijun Wang ◽  
Nagore Marin Ramos ◽  
Axel Schonthal
Keyword(s):  
Tight Junction ◽  
Blood Brain Barrier ◽  
In Vitro Models ◽  
Brain Barrier ◽  
In Vivo Studies ◽  
Blue Dye ◽  
Blood Brain ◽  
Main Technique

Abstract The blood brain barrier (BBB) prevents effective entry of nearly all therapeutics to the central nervous system (CNS), preventing effective treatment of brain-related malignancies. Intracarotid mannitol injection has been the main technique to transiently open up the BBB, with its attendant variability and complications. A more direct and better tolerated method is needed to open up the BBB. We present our discovery that intraarterial (IA) injection of NEO100, a cGMP-quality form of perillyl alcohol (POH), transiently opens up the BBB in a safe and reversible manner. We used in-vitro models of MDCK1 and patient derived brain endothelial cell (BEC) + astrocyte barriers to determine that NEO100 increased FITC-antibody diffusion across the in-vitro BBB model and decreased trans-epithelial/endothelial electrical resistance (TEER). NEO100 effects on transcellular and paracellular pathways were studied using western blot, flow cytometry, HPLC, fluorescent probes, microarray analysis, and transmission electron microscopy. In-vivo studies were performed using ultrasound-guided intracardiac administration of NEO100 in mice with subsequent intravenous delivery of non-BBB permeable therapeutic agents. We determined that NEO100 transiently disrupts the transcellular pathway by permeabilizing BEC membranes, and the paracellular pathway via delocalization of tight junction proteins. In vivo IA NEO100 administration caused an effective dose- and time-dependent BBB permeabilization, which was reversible and well tolerated by the mice. This was evidenced by the spreading of Evans blue dye, and of therapeutics with different molecular weights, ie methotrexate, anti-PD-1 antibody, and CAR-T cells in the brain. Our results demonstrate that IA NEO100 is able to open the BBB in a controlled and reversible manner, allowing it to facilitate drug delivery to the CNS.

scholarly journals Maf1 Ameliorates Sepsis-Associated Encephalopathy by Suppressing the NF-kB/NLRP3 Inflammasome Signaling Pathway

2020 ◽  
Vol 11 ◽  
Author(s):  
Shenglong Chen ◽  
Chaogang Tang ◽  
Hongguang Ding ◽  
Zhonghua Wang ◽  
Xinqiang Liu ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Inflammatory Cytokines ◽  
Nlrp3 Inflammasome ◽  
Brain Barrier ◽  
Blue Dye ◽  
Inflammasome Activation ◽  
Blood Brain ◽  
Pro Inflammatory Cytokines

BackgroundThe NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome has been identified as an important mediator of blood–brain-barrier disruption in sepsis-associated encephalopathy (SAE). However, no information is available concerning the critical upstream regulators of SAE.MethodsLipopolysaccharide (LPS) was used to establish an in vitro model of blood–brain barrier (BBB) disruption and an in vivo model of SAE. Disruption of BBB integrity was assessed by measuring the expression levels of tight-junction proteins. NLRP3 inflammasome activation, pro-inflammatory cytokines levels, and neuroapoptosis were measured using biochemical assays. Finally, the FITC-dextran Transwell assay and Evan’s blue dye assay were used to assess the effect of Maf1 on LPS-induced endothelial permeability in vitro and in vivo.ResultsWe found that Maf1 significantly suppressed the brain inflammatory response and neuroapoptosis induced by LPS in vivo and in vitro. Notably, Maf1 downregulated activation of the NF-κB/p65-induced NLRP3 inflammasome and the expression of pro-inflammatory cytokines. In addition, we found that Maf1 and p65 directly bound to the NLRP3 gene promoter region and competitively regulated the function of NLRP3 in inflammations. Moreover, overexpression of NLRP3 reversed the effects of p65 on BBB integrity, apoptosis, and inflammation in response to LPS. Our study revealed novel role for Maf1 in regulating NF-κB-mediated inflammasome formation, which plays a prominent role in SAE.ConclusionsRegulation of Maf1 might be a therapeutic strategy for SAE and other neurodegenerative diseases associated with inflammation.

scholarly journals Simvastatin Blocks Blood-Brain Barrier Disruptions Induced by Elevated Cholesterol Both In Vivo and In Vitro

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Xijuan Jiang ◽  
Maojuan Guo ◽  
Jinling Su ◽  
Bin Lu ◽  
Dongming Ma ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Cholesterol Content ◽  
Brain Barrier ◽  
Blue Dye ◽  
Simvastatin Therapy ◽  
Blood Brain ◽  
Elevated Cholesterol ◽  
Underlying Mechanisms

Background. Hypercholesterolemia and disruptions of the blood brain barrier (BBB) have been implicated as underlying mechanisms in the pathogenesis of Alzheimer's disease (AD). Simvastatin therapy may be of benefit in treating AD; however, its mechanism has not been yet fully understood.Objective. To explore whether simvastatin could block disruption of BBB induced by cholesterol both in vivo and in vitro.Methods. New Zealand rabbits were fed cholesterol-enriched diet with or without simvastatin. Total cholesterol of serum and brain was measured. BBB dysfunction was evaluated. To further test the results in vivo, rat brain microvascular endothelial cells (RBMECs) were stimulated with cholesterol in the presence/absence of simvastatin in vitro. BBB disruption was evaluated.Results. Simvastatin blocked cholesterol-rich diet induced leakage of Evan's blue dye. Cholesterol content in the serum was affected by simvastatin, but not brain cholesterol. Simvastatin blocked high-cholesterol medium-induced decrease in TEER and increase in transendothelial FITC-labeled BSA Passage in RBMECs.Conclusions. The present study firstly shows that simvastatin improves disturbed BBB function both in vivo and in vitro. Our data provide that simvastatin may be useful for attenuating disturbed BBB mediated by hypercholesterolemia.

scholarly journals The Potential Roles of Blood–Brain Barrier and Blood–Cerebrospinal Fluid Barrier in Maintaining Brain Manganese Homeostasis

Nutrients ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1833
Author(s):  
Shannon Morgan McCabe ◽  
Ningning Zhao
Keyword(s):  
Cerebrospinal Fluid ◽  
Blood Brain Barrier ◽  
Blood Circulation ◽  
Critical Role ◽  
Systemic Circulation ◽  
Brain Parenchyma ◽  
Brain Barrier ◽  
Blood Brain ◽  
The Brain

Manganese (Mn) is a trace nutrient necessary for life but becomes neurotoxic at high concentrations in the brain. The brain is a “privileged” organ that is separated from systemic blood circulation mainly by two barriers. Endothelial cells within the brain form tight junctions and act as the blood–brain barrier (BBB), which physically separates circulating blood from the brain parenchyma. Between the blood and the cerebrospinal fluid (CSF) is the choroid plexus (CP), which is a tissue that acts as the blood–CSF barrier (BCB). Pharmaceuticals, proteins, and metals in the systemic circulation are unable to reach the brain and spinal cord unless transported through either of the two brain barriers. The BBB and the BCB consist of tightly connected cells that fulfill the critical role of neuroprotection and control the exchange of materials between the brain environment and blood circulation. Many recent publications provide insights into Mn transport in vivo or in cell models. In this review, we will focus on the current research regarding Mn metabolism in the brain and discuss the potential roles of the BBB and BCB in maintaining brain Mn homeostasis.

Activation of PKC modulates blood-brain barrier endothelial cell permeability changes induced by hypoxia and posthypoxic reoxygenation

2005 ◽  
Vol 289 (5) ◽  
pp. H2012-H2019 ◽  
Author(s):  
Melissa A. Fleegal ◽  
Sharon Hom ◽  
Lindsay K. Borg ◽  
Thomas P. Davis
Keyword(s):  
Blood Brain Barrier ◽  
Paracellular Permeability ◽  
Cell Permeability ◽  
Brain Barrier ◽  
Cerebral Microvessels ◽  
Permeability Changes ◽  
Blood Brain ◽  
Brain Microvessel

The blood-brain barrier (BBB) is a metabolic and physiological barrier important for maintaining brain homeostasis. The aim of this study was to determine the role of PKC activation in BBB paracellular permeability changes induced by hypoxia and posthypoxic reoxygenation using in vitro and in vivo BBB models. In rat brain microvessel endothelial cells (RMECs) exposed to hypoxia (1% O2-99% N2; 24 h), a significant increase in total PKC activity was observed, and this was reduced by posthypoxic reoxygenation (95% room air-5% CO2) for 2 h. The expression of PKC-βII, PKC-γ, PKC-η, PKC-μ, and PKC-λ also increased following hypoxia (1% O2-99% N2; 24 h), and these protein levels remained elevated following posthypoxic reoxygenation (95% room air-5% CO2; 2 h). Increases in the expression of PKC-ε and PKC-ζ were also observed following posthypoxic reoxygenation (95% room air-5% CO2; 2 h). Moreover, inhibition of PKC with chelerythrine chloride (10 μM) attenuated the hypoxia-induced increases in [14C]sucrose permeability. Similar to what was observed in RMECs, total PKC activity was also stimulated in cerebral microvessels isolated from rats exposed to hypoxia (6% O2-94% N2; 1 h) and posthypoxic reoxygenation (room air; 10 min). In contrast, hypoxia (6% O2-94% N2; 1 h) and posthypoxic reoxygenation (room air; 10 min) significantly increased the expression levels of only PKC-γ and PKC-θ in the in vivo hypoxia model. These data demonstrate that hypoxia-induced BBB paracellular permeability changes occur via a PKC-dependent mechanism, possibly by differentially regulating the protein expression of the 11 PKC isozymes.

Refining In Vitro Neurotoxicity Testing — The Development of Blood–Brain Barrier Models

2003 ◽  
Vol 31 (3) ◽  
pp. 273-276 ◽  
Author(s):  
Hanna Tähti ◽  
Heidi Nevala ◽  
Tarja Toimela
Keyword(s):  
Blood Brain Barrier ◽  
Cell Lines ◽  
Three Dimensional ◽  
Brain Barrier ◽  
Culture Methods ◽  
Blood Brain ◽  
Capillary Endothelial Cells ◽  
In Vitro Bbb Model

The purpose of this paper is to review the current state of development of advanced in vitro blood–brain barrier (BBB) models. The BBB is a special capillary bed that separates the blood from the central nervous system (CNS) parenchyma. Astrocytes maintain the integrity of the BBB, and, without astrocytic contacts, isolated brain capillary endothelial cells in culture lose their barrier characteristics. Therefore, when developing in vitro BBB models, it is important to add astrocytic factors into the culture system. Recently, novel filter techniques and co-culture methods have made it possible to develop models which resemble the in vivo functions of the BBB in an effective way. With a BBB model, kinetic factors can be added into the in vitro batteries used for evaluating the neurotoxic potential of chemicals. The in vitro BBB model also represents a useful tool for the in vitro prediction of the BBB permeability of drugs, and offers the possibility to scan a large number of drugs for their potential to enter the CNS. Cultured monolayers of brain endothelial cell lines or selected epithelial cell lines, combined with astrocyte and neuron cultures, form a novel three-dimensional technique for the screening of neurotoxic compounds.

scholarly journals Proof-of-Concept Study of Drug Brain Permeability Between in Vivo Human Brain and an in Vitro iPSCs-Human Blood-Brain Barrier Model

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Gwenaëlle Le Roux ◽  
Rafika Jarray ◽  
Anne-Cécile Guyot ◽  
Serena Pavoni ◽  
Narciso Costa ◽  
...  
Keyword(s):  
Human Brain ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Pharmacokinetic Parameters ◽  
Pharmacokinetic Data ◽  
Apparent Permeability ◽  
Clinical Drug Development ◽  
Blood Brain

Abstract The development of effective central nervous system (CNS) drugs has been hampered by the lack of robust strategies to mimic the blood-brain barrier (BBB) and cerebrovascular impairments in vitro. Recent technological advancements in BBB modeling using induced pluripotent stem cells (iPSCs) allowed to overcome some of these obstacles, nonetheless the pertinence for their use in drug permeation study remains to be established. This mandatory information requires a cross comparison of in vitro and in vivo pharmacokinetic data in the same species to avoid failure in late clinical drug development. Here, we measured the BBB permeabilities of 8 clinical positron emission tomography (PET) radioligands with known pharmacokinetic parameters in human brain in vivo with a newly developed in vitro iPSC-based human BBB (iPSC-hBBB) model. Our findings showed a good correlation between in vitro and in vivo drug brain permeability (R2 = 0.83; P = 0.008) which contrasted with the limited correlation between in vitro apparent permeability for a set of 18 CNS/non-CNS compounds using the in vitro iPSCs-hBBB model and drug physicochemical properties. Our data suggest that the iPSC-hBBB model can be integrated in a flow scheme of CNS drug screening and potentially used to study species differences in BBB permeation.

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