scholarly journals DDEL-04. ENGINEERED NANOCARRIERS TO ENHANCE DRUG DELIVERY ACROSS THE BLOOD-BRAIN BARRIER

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii284-iii284
Author(s):  
Joelle P Straehla ◽  
Cynthia Hajal ◽  
Hannah Safford ◽  
Giovanni Offeddu ◽  
Jeffrey Wyckoff ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Layer By Layer ◽  
Two Photon Microscopy ◽  
Cranial Window ◽  
Blood Brain ◽  
Intact Brain ◽  
Preferential Uptake

Abstract Pediatric central nervous system tumors are the leading cause of cancer death in children. Promising therapeutics have been identified, but the ability to deliver an effective concentration to the tumor without causing excessive systemic toxicity remains a challenge. To address this, we leveraged a tunable nanocarrier platform to design a brain-penetrant nanocarrier with preferential uptake into tumor cells over healthy brain cells. First, we used the layer-by-layer technique to iteratively coat liposomes with nanometers-thick layers of oppositely charged polyelectrolytes. To investigate the influence of surface chemistry on cellular trafficking, a panel of layered liposomes was tested for interactions with cancer cell lines, identifying poly-L-aspartic acid and hyaluronic acid as the highest-performing formulations across brain tumor lines. To facilitate nanocarrier transit across the blood-brain barrier (BBB), we developed a click chemistry platform to functionalize the nanocarrier with BBB shuttle ligands. To investigate trafficking in vitro, we utilized a microfluidic brain microvascular model comprising endothelial cells, astrocytes, pericytes, and glioma cells that self-assemble into a perfusable vascular network. We found that nanocarrier size influenced vascular transport, and the addition of BBB shuttle ligands improved transport in the presence of a glioma spheroid. To investigate in vivo nanocarrier trafficking, we performed intravital imaging through a cranial window in anesthetized mice. After intravenous administration, nanocarrier transit across intact brain capillaries was visualized using two photon microscopy, and vessel permeability was quantified over time. Ongoing studies in mice bearing patient-derived xenograft medulloblastoma and glioma tumors are being conducted to further characterize trafficking across tumor-associated vasculature.

scholarly journals Cerebromicrovascular endothelial cells are resistant to l-glutamate

2008 ◽  
Vol 295 (4) ◽  
pp. R1099-R1108 ◽  
Author(s):  
Ferenc Domoki ◽  
Béla Kis ◽  
Tamás Gáspár ◽  
Ferenc Bari ◽  
David W. Busija
Keyword(s):  
Endothelial Cells ◽  
Blood Brain Barrier ◽  
Primary Cultures ◽  
Glucose Deprivation ◽  
Brain Barrier ◽  
Cranial Window ◽  
Blood Brain ◽  
Microvascular Cells

Cerebral microvascular endothelial cells (CMVECs) have recently been implicated as targets of excitotoxic injury by l-glutamate (l-glut) or N-methyl-d-aspartate (NMDA) in vitro. However, high levels of l-glut do not compromise the function of the blood-brain barrier in vivo. We sought to determine whether primary cultures of rat and piglet CMVECs or cerebral microvascular pericytes (CMVPCs) are indeed sensitive to l-glut or NMDA. Viability was unaffected by 8-h exposure to 1–10 mM l-glut or NMDA in CMVECs or CMVPCs isolated from both species. Furthermore, neither 1 mM l-glut nor NMDA augmented cell death induced by 12-h oxygen-glucose deprivation in rat CMVECs or by 8-h medium withdrawal in CMVPCs. Additionally, transendothelial electrical resistance of rat CMVEC-astrocyte cocultures or piglet CMVEC cultures were not compromised by up to 24-h exposure to 1 mM l-glut or NMDA. The Ca2+ ionophore calcimycin (5 μM), but not l-glut (1 mM), increased intracellular Ca2+ levels in rat CMVECs and CMVPCs assessed with fluo-4 AM fluorescence and confocal microscopy. CMVEC-dependent pial arteriolar vasodilation to hypercapnia and bradykinin was unaffected by intracarotid infusion of l-glut in anesthetized piglets by closed cranial window/intravital microscopy. We conclude that cerebral microvascular cells are insensitive and resistant to glutamatergic stimuli in accordance with their in vivo role as regulators of potentially neurotoxic amino acids across the blood-brain barrier.

EXTH-26. LAYER-BY-LAYER NANOPARTICLES DESIGNED FOR DUAL BLOOD-BRAIN BARRIER AND GLIOMA TARGETING

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi168-vi169
Author(s):  
Joelle Straehla ◽  
Cynthia Hajal ◽  
Hannah Safford ◽  
Giovanni Offeddu ◽  
Jeffrey Wyckoff ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Drug Exposure ◽  
Drug Carriers ◽  
Brain Barrier ◽  
Layer By Layer ◽  
Cranial Window ◽  
Tumor Bearing ◽  
Blood Brain ◽  
Dismal Prognosis

Abstract BACKGROUND While biologically diverse, high grade gliomas (HGGs) have a dismal prognosis in both adults and children. Promising therapeutics have been identified for HGGs based on common genomic alterations and aberrant signaling pathways, but achieving effective drug exposure at the tumor site remains a challenge largely due to the blood-brain barrier (BBB). HYPOTHESIS: A tunable nanocarrier platform can improve nanoparticle delivery across the (BBB) and into glioma cells. METHODS We synthesized layer-by-layer nanoparticles by coating anionic, fluorescent liposomes with nanometers-thick layers of oppositely charged polyelectrolytes, creating a library of organic, nontoxic drug carriers with varied surface chemistries. We characterized the library using dynamic light scattering and quantified interactions with a range of pediatric and adult glioma cell lines using flow cytometry. We used intravital two-photon microscopy to quantify nanoparticle trafficking across the intact BBB through a cranial window in anesthetized mice. RESULTS Nanoparticle surface chemistry strongly influences cellular trafficking in vitro, with two polymers identified as particularly high-performing across brain tumors lines: poly-L-aspartic acid (semi-synthetic) and hyaluronic acid (natural polysaccharide). The addition of the angiopep-2 targeting moiety onto these polymers improved nanoparticle uptake into brain microvascular endothelial cells in vitro without abrogating tumor affinity. We developed a new algorithm to quantify permeability of fluorescent compounds across the BBB in vivo and validated our method by measuring dextran permeability at varied molecular weights. In our initial study in non-tumor-bearing mice (n=12), we successfully quantified nanoparticle permeability across the BBB. In this study, surface functionalization did not increase BBB permeability above the control nanoparticle, though it did improve nanoparticle half-life in circulation and may still impart a therapeutic benefit when loaded with drug. Additional investigations in orthotopic tumor-bearing mice are ongoing. In summary, we report the development of layer-by-layer nanocarriers as a modular drug delivery platform with therapeutic potential for gliomas.

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.

scholarly journals Baicalein as a Potential Inhibitor against BACE1 and AChE: Mechanistic Comprehension through In Vitro and Computational Approaches

Nutrients ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2694 ◽  
Author(s):  
Jin Han ◽  
Yeongseon Ji ◽  
Kumju Youn ◽  
GyuTae Lim ◽  
Jinhyuk Lee ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Efflux Pump ◽  
Critical Role ◽  
Brain Barrier ◽  
Hydroxyl Groups ◽  
Binding Interaction ◽  
In Silico Docking ◽  
Blood Brain

One of the major neurodegenerative features of Alzheimer’s disease (AD) is the presence of neurotoxic amyloid plaques composed of amyloid beta peptide (Aβ). β-Secretase (BACE1) and acetylcholinesterase (AChE), which promote Aβ fibril formation, have become attractive therapeutic targets for AD. P-glycoprotein (P-gp), the major efflux pump of the blood-brain barrier (BBB), plays a critical role in limiting therapeutic molecules. In pursuit of discovering a natural anti-AD candidate, the bioactivity, physicochemical, drug-likeness, and molecular docking properties of baicalein, a major compound from Scutellaria baicalensis, was investigated. Baicalein exhibited strong BACE1 and AChE inhibitory properties (IC50 23.71 ± 1.91 µM and 45.95 ± 3.44 µM, respectively) and reacted in non-competitive and competitive manners with substrates, respectively. in Silico docking analysis was in full agreement with the in vitro results, demonstrating that the compound exhibited powerful binding interaction with target enzymes. Particularly, three continuous hydroxyl groups on the A ring demonstrated strong H-bond binding properties. It is also noteworthy that baicalein complied with all requirements of Lipinski’s rule of five by its optimal physicochemical properties for both oral bioavailability and blood–brain barrier permeability. Overall, the present study strongly demonstrated the possibility of baicalein having in vivo pharmacological efficacy for specific targets in the prevention and/or treatment of AD.

scholarly journals Kidney Ischemia/Reperfusion Injury Induces Changes in the Drug Transporter Expression at the Blood–Brain Barrier in vivo and in vitro

2020 ◽  
Vol 11 ◽  
Author(s):  
Malgorzata Burek ◽  
Sandra Burmester ◽  
Ellaine Salvador ◽  
Kerstin Möller-Ehrlich ◽  
Reinhard Schneider ◽  
...  
Keyword(s):  
Reperfusion Injury ◽  
Blood Brain Barrier ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Brain Barrier ◽  
Drug Transporter ◽  
Blood Brain ◽  
Transporter Expression
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