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Sample records for blood-brain tumor barrier

  1. Effective transvascular delivery of nanoparticles across the blood-brain tumor barrier into malignant glioma cells

    PubMed Central

    Sarin, Hemant; Kanevsky, Ariel S; Wu, Haitao; Brimacombe, Kyle R; Fung, Steve H; Sousa, Alioscka A; Auh, Sungyoung; Wilson, Colin M; Sharma, Kamal; Aronova, Maria A; Leapman, Richard D; Griffiths, Gary L; Hall, Matthew D

    2008-01-01

    Background Effective transvascular delivery of nanoparticle-based chemotherapeutics across the blood-brain tumor barrier of malignant gliomas remains a challenge. This is due to our limited understanding of nanoparticle properties in relation to the physiologic size of pores within the blood-brain tumor barrier. Polyamidoamine dendrimers are particularly small multigenerational nanoparticles with uniform sizes within each generation. Dendrimer sizes increase by only 1 to 2 nm with each successive generation. Using functionalized polyamidoamine dendrimer generations 1 through 8, we investigated how nanoparticle size influences particle accumulation within malignant glioma cells. Methods Magnetic resonance and fluorescence imaging probes were conjugated to the dendrimer terminal amines. Functionalized dendrimers were administered intravenously to rodents with orthotopically grown malignant gliomas. Transvascular transport and accumulation of the nanoparticles in brain tumor tissue was measured in vivo with dynamic contrast-enhanced magnetic resonance imaging. Localization of the nanoparticles within glioma cells was confirmed ex vivo with fluorescence imaging. Results We found that the intravenously administered functionalized dendrimers less than approximately 11.7 to 11.9 nm in diameter were able to traverse pores of the blood-brain tumor barrier of RG-2 malignant gliomas, while larger ones could not. Of the permeable functionalized dendrimer generations, those that possessed long blood half-lives could accumulate within glioma cells. Conclusion The therapeutically relevant upper limit of blood-brain tumor barrier pore size is approximately 11.7 to 11.9 nm. Therefore, effective transvascular drug delivery into malignant glioma cells can be accomplished by using nanoparticles that are smaller than 11.7 to 11.9 nm in diameter and possess long blood half-lives. PMID:19094226

  2. Novel delivery methods bypassing the blood-brain and blood-tumor barriers.

    PubMed

    Hendricks, Benjamin K; Cohen-Gadol, Aaron A; Miller, James C

    2015-03-01

    Glioblastoma (GBM) is the most common primary brain tumor and carries a grave prognosis. Despite years of research investigating potentially new therapies for GBM, the median survival rate of individuals with this disease has remained fairly stagnant. Delivery of drugs to the tumor site is hampered by various barriers posed by the GBM pathological process and by the complex physiology of the blood-brain and blood-cerebrospinal fluid barriers. These anatomical and physiological barriers serve as a natural protection for the brain and preserve brain homeostasis, but they also have significantly limited the reach of intraparenchymal treatments in patients with GBM. In this article, the authors review the functional capabilities of the physical and physiological barriers that impede chemotherapy for GBM, with a specific focus on the pathological alterations of the blood-brain barrier (BBB) in this disease. They also provide an overview of current and future methods for circumventing these barriers in therapeutic interventions. Although ongoing research has yielded some potential options for future GBM therapies, delivery of chemotherapy medications across the BBB remains elusive and has limited the efficacy of these medications. PMID:25727219

  3. Blood Brain Barrier: A Challenge for Effectual Therapy of Brain Tumors

    PubMed Central

    Bhowmik, Arijit; Ghosh, Mrinal Kanti

    2015-01-01

    Brain tumors are one of the most formidable diseases of mankind. They have only a fair to poor prognosis and high relapse rate. One of the major causes of extreme difficulty in brain tumor treatment is the presence of blood brain barrier (BBB). BBB comprises different molecular components and transport systems, which in turn create efflux machinery or hindrance for the entry of several drugs in brain. Thus, along with the conventional techniques, successful modification of drug delivery and novel therapeutic strategies are needed to overcome this obstacle for treatment of brain tumors. In this review, we have elucidated some critical insights into the composition and function of BBB and along with it we have discussed the effective methods for delivery of drugs to the brain and therapeutic strategies overcoming the barrier. PMID:25866775

  4. Is the Blood-Brain Barrier Relevant in Metastatic Germ Cell Tumor?

    SciTech Connect

    Azar, Jose M. Schneider, Bryan P.; Einhorn, Lawrence H.

    2007-09-01

    Purpose: Germ cell tumors are uniquely chemosensitive and curable, even with advanced metastatic disease. Central nervous system recurrence can terminate a complete remission in other chemosensitive tumors, such as small cell lung cancer, because of the blood-brain barrier (BBB). We propose to document that the BBB is also relevant in germ cell tumors despite their dramatic chemosensitivity. Methods and Materials: We present five cases illustrating the concept of the BBB in patients with metastatic testicular cancer treated with chemotherapy. Results: In our large series of patients with metastatic testicular cancer treated with chemotherapy, we identified 5 unique patients. These patients were rendered free of disease only to experience relapse in the brain alone. This included 1 patient who initially had good-risk metastatic disease by means of the International Germ Cell Collaborative Group staging system at the onset of chemotherapy. Conclusions: The BBB is relevant in patients with metastatic testicular cancer.

  5. Tumor necrosis factor and stroke: role of the blood-brain barrier

    PubMed Central

    Pan, Weihong; Kastin, Abba J.

    2008-01-01

    The progression and outcome of stroke is affected by the intricate relationship between the blood-brain barrier (BBB) and tumor necrosis factor α (TNFα). TNFα crosses the intact BBB by a receptor-mediated transport system that is upregulated by CNS trauma and inflammation. In this review, we discuss intracellular trafficking and transcytosis of TNFα, regulation of TNFα transport after stroke, and the effects of TNFα on stroke preconditioning. TNFα can activate cytoprotective pathways by pretreatment or persistent exposure to low doses. This explains the paradoxical observation that transport of this proinflammatory cytokine improves the survival and function of hypoxic cells and of mice with stroke. The dual effects of TNFα may be related to differential regulation of TNFα trafficking downstream to TNFR1 and TNFR2 receptors. As we better understand how peripheral TNFα affects its own transport and modulates neuroregeneration, we may be in a better position to pharmacologically manipulate its regulatory transport system to treat stroke. PMID:17913328

  6. [Magnetic resonance tomographic characterization of intracranial tumors by evaluating the blood-brain barrier and regional cerebral circulation].

    PubMed

    Böck, J C; Sander, B; Schedel, H; Felix, R

    1993-11-01

    The aim of this prospective study was to characterize intracranial tumors on the basis of the degree of blood-brain-barrier (BBB) disruption and tumor blood flow (TBF). We studied 28 patients with brain tumors by MRI. BBB disruption was demonstrated by a pathological increase of signal intensity in T1-weighted spin-echo images (1.5 T, TR = 600 ms, TE = 10 ms, alpha = 90 degrees) after intravenous gadolinium-DTPA injection. TBF flow was assessed by an MRI-method based on the signal intensity decrease in T2-weighted gradient-echo images (TR = 25 ms, TE = 20 ms, alpha = 10 degrees) immediately after gadolinium-DTPA bolus injection. Typical constellations include intake BBB and low TBF in low-grade intraaxial tumors (astrocytoma I/II), disrupted BBB and heterogeneous TBF in high-grade intraaxial tumors (glioblastomas and metastases), and disrupted BBB and high TBF in extraaxial tumors (meningeomas). This study demonstrates the quasi-simultaneous assessment of the blood-brain-barrier and tumor blood flow. The results support the concept that additional uncorrelated information is obtained from the assessment of regional cerebral blood flow that may be helpful for the differential diagnosis of brain tumors. PMID:8241297

  7. Retro-inverso bradykinin opens the door of blood-brain tumor barrier for nanocarriers in glioma treatment.

    PubMed

    Xie, Zuoxu; Shen, Qing; Xie, Cao; Lu, Weiyue; Peng, Chunmei; Wei, Xiaoli; Li, Xue; Su, Bingxia; Gao, Chunli; Liu, Min

    2015-12-01

    The blood-brain barrier and the blood-brain tumor barrier (BBTB) prevent most drugs entering brain tumors. Complicated preparation procedures of drug delivery systems and damage to normal brain tissue have limited the application of many strategies for the treatment of brain tumor in clinical trials. We have designed a bradykinin analog, retro-inverso bradykinin (RI-BK), which is characterized by resistance to proteolysis and high binding activity with the bradykinin type 2 (B2) receptor. After systemic administration, RI-BK binds to B2 receptors and induces a change in zonula occluden-1 and depolymerization of F-actin to selectively open the BBTB. RI-BK increased the accumulation of drug-loaded nanocarriers in the glioma but not in normal brain. Co-administration with RI-BK enhanced the therapeutic efficiency of drug-loaded nanocarriers for glioma. These findings suggest that RI-BK could be translated into the clinic as an adjunctive treatment for malignant brain tumors. PMID:26282786

  8. Impacts of Blood-Brain Barrier in Drug Delivery and Targeting of Brain Tumors

    PubMed Central

    Omidi, Yadollah; Barar, Jaleh

    2012-01-01

    Introduction Entry of blood circulating agents into the brain is highly selectively con-trolled by specific transport machineries at the blood brain barrier (BBB), whose excellent barrier restrictiveness make brain drug delivery and targeting very challenging. Methods Essential information on BBB cellular microenvironment were reviewed and discussed towards impacts of BBB on brain drug delivery and targeting. Results Brain capillary endothelial cells (BCECs) form unique biological structure and architecture in association with astrocytes and pericytes, in which microenvironment the BCECs express restrictive tight junctional complexes that block the paracellular inward/outward traverse of biomolecules/compounds. These cells selectively/specifically control the transportation process through carrier and/or receptor mediated transport machineries that can also be exploited for the delivery of pharmaceuticals into the brain. Intelligent molecular therapies should be designed using such transport machineries for the efficient delivery of designated drugs into the brain. For better clinical outcomes, these smart pharmaceuticals should be engineered as seamless nanosystems to provide simultaneous imaging and therapy (multimodal theranostics). Conclusion The exceptional functional presence of BBB selectively controls inward and outward transportation mechanisms, thus advanced smart multifunctional nanomedicines are needed for the effective brain drug delivery and targeting. Fully understanding the biofunctions of BBB appears to be a central step for engineering of intelligent seamless therapeutics consisting of homing device for targeting, imaging moiety for detecting, and stimuli responsive device for on-demand liberation of therapeutic agent. PMID:23678437

  9. The blood-brain and blood-tumor barriers: a review of strategies for increasing drug delivery.

    PubMed Central

    Groothuis, D. R.

    2000-01-01

    Drug delivery to brain tumors has been a controversial subject. Some believe the blood-brain barrier is not important, while others believe it is the major obstacle in treatment and have devised innovative approaches to circumvent it. These approaches can be divided into two categories: those that attempt to increase drug delivery of intravascularly administered drugs by manipulating either the drugs or capillary permeability, and those that attempt to increase drug delivery by local administration. Several strategies have been developed to increase the fraction of intravascular drug reaching the tumor, including intra-arterial administration, barrier disruption, new ways of packaging drugs, and, most recently, inhibiting drug efflux from tumor. When given intravascularly, all drugs have a common drawback: the body acts as a sink, and, even in the best situations, only a small fraction of administered drug actually reaches the tumor. A consequence is that systemic toxicity is usually the dose-limiting factor. When given locally, such as into the cerebrospinal fluid or directly into the tumor, 100% of an administered dose is delivered to the target site. However, local delivery is associated with variable and unpredictable spatial distribution and variation in drug concentration. The major dose-limiting factor of most local delivery methods will be neurotoxicity. The relative advantages and disadvantages of the different methods of circumventing the blood-brain barrier are presented in this review, and special attention is given to convection-enhanced delivery, which has particular promise for the local delivery of large therapeutic agents such as monoclonal antibodies, antisense oligonucleotides, or viral vectors. PMID:11302254

  10. The blood-brain barrier.

    PubMed

    Obermeier, Birgit; Verma, Ajay; Ransohoff, Richard M

    2016-01-01

    In autoimmune neurologic disorders, the blood-brain barrier (BBB) plays a central role in immunopathogenesis, since this vascular interface is an entry path for cells and effector molecules of the peripheral immune system to reach the target organ, the central nervous system (CNS). The BBB's unique anatomic structure and the tightly regulated interplay of its cellular and acellular components allow for maintenance of brain homeostasis, regulation of influx and efflux, and protection from harm; these ensure an optimal environment for the neuronal network to function properly. In both health and disease, the BBB acts as mediator between the periphery and the CNS. For example, immune cell trafficking through the cerebral vasculature is essential to clear microbes or cell debris from neural tissues, while poorly regulated cellular transmigration can underlie or worsen CNS pathology. In this chapter, we focus on the specialized multicellular structure and function of the BBB/neurovascular unit and discuss how BBB breakdown can precede or be a consequence of neuroinflammation. We introduce the blood-cerebrospinal fluid barrier and include a brief aside about evolutionary aspects of barrier formation and refinements. Lastly, since restoration of barrier function is considered key to ameliorate neurologic disease, we speculate about new therapeutic avenues to repair a damaged BBB. PMID:27112670

  11. Blood-Brain Barrier and Breast Cancer Resistance Protein: A Limit to the Therapy of CNS Tumors and Neurodegenerative Diseases

    PubMed Central

    Iorio, Anna Lisa; da Ros, Martina; Fantappiè, Ornella; Lucchesi, Maurizio; Facchini, Ludovica; Stival, Alessia; Becciani, Sabrina; Guidi, Milena; Favre, Claudio; de Martino, Maurizio; Genitori, Lorenzo; Sardi, Iacopo

    2016-01-01

    The treatment of brain tumors and neurodegenerative diseases, represents an ongoing challenge. In Central Nervous System (CNS) the achievement of therapeutic concentration of chemical agents is complicated by the presence of distinct set of efflux proteins, such as ATP-Binding Cassette (ABC) transporters localized on the Blood-Brain Barrier (BBB). The activity of ABC transporters seems to be a common mechanism that underlies the poor response of CNS diseases to therapies. The molecular characterization of Breast Cancer Resistance Protein (BCRP/ABCG2), as an ABC transporter conferring multidrug resistance (MDR), has stimulated many studies to investigate its activity on the BBB, its involvement in physiology and CNS diseases and its role in limiting the delivery of drugs in CNS. In this review, we highlight the activity and localization of BCRP on the BBB and the action that this efflux pump has on many conventional drugs or latest generation molecules used for the treatment of CNS tumors and other neurodegenerative diseases. PMID:26584727

  12. Blood-Brain Barrier and Breast Cancer Resistance Protein: A Limit to the Therapy of CNS Tumors and Neurodegenerative Diseases.

    PubMed

    Iorio, Anna Lisa; Ros, Martina da; Fantappiè, Ornella; Lucchesi, Maurizio; Facchini, Ludovica; Stival, Alessia; Becciani, Sabrina; Guidi, Milena; Favre, Claudio; Martino, Maurizio de; Genitori, Lorenzo; Sardi, Iacopo

    2016-01-01

    The treatment of brain tumors and neurodegenerative diseases, represents an ongoing challenge. In Central Nervous System (CNS) the achievement of therapeutic concentration of chemical agents is complicated by the presence of distinct set of efflux proteins, such as ATP-Binding Cassette (ABC) transporters localized on the Blood-Brain Barrier (BBB). The activity of ABC transporters seems to be a common mechanism that underlies the poor response of CNS diseases to therapies. The molecular characterization of Breast Cancer Resistance Protein (BCRP/ABCG2), as an ABC transporter conferring multidrug resistance (MDR), has stimulated many studies to investigate its activity on the BBB, its involvement in physiology and CNS diseases and its role in limiting the delivery of drugs in CNS. In this review, we highlight the activity and localization of BCRP on the BBB and the action that this efflux pump has on many conventional drugs or latest generation molecules used for the treatment of CNS tumors and other neurodegenerative diseases. PMID:26584727

  13. Optically enhanced blood-brain-barrier crossing of plasmonic-active nanoparticles in preclinical brain tumor animal models

    NASA Astrophysics Data System (ADS)

    Yuan, Hsiangkuo; Wilson, Christy M.; Li, Shuqin; Fales, Andrew M.; Liu, Yang; Grant, Gerald; Vo-Dinh, Tuan

    2014-02-01

    Nanotechnology provides tremendous biomedical opportunities for cancer diagnosis, imaging, and therapy. In contrast to conventional chemotherapeutic agents where their actual target delivery cannot be easily imaged, integrating imaging and therapeutic properties into one platform facilitates the understanding of pharmacokinetic profiles, and enables monitoring of the therapeutic process in each individual. Such a concept dubbed "theranostics" potentiates translational research and improves precision medicine. One particular challenging application of theranostics involves imaging and controlled delivery of nanoplatforms across blood-brain-barrier (BBB) into brain tissues. Typically, the BBB hinders paracellular flux of drug molecules into brain parenchyma. BBB disrupting agents (e.g. mannitol, focused ultrasound), however, suffer from poor spatial confinement. It has been a challenge to design a nanoplatform not only acts as a contrast agent but also improves the BBB permeation. In this study, we demonstrated the feasibility of plasmonic gold nanoparticles as both high-resolution optical contrast agent and focalized tumor BBB permeation-inducing agent. We specifically examined the microscopic distribution of nanoparticles in tumor brain animal models. We observed that most nanoparticles accumulated at the tumor periphery or perivascular spaces. Nanoparticles were present in both endothelial cells and interstitial matrices. This study also demonstrated a novel photothermal-induced BBB permeation. Fine-tuning the irradiating energy induced gentle disruption of the vascular integrity, causing short-term extravasation of nanomaterials but without hemorrhage. We conclude that our gold nanoparticles are a powerful biocompatible contrast agent capable of inducing focal BBB permeation, and therefore envision a strong potential of plasmonic gold nanoparticle in future brain tumor imaging and therapy.

  14. Boron neutron capture therapy of brain tumors: Enhanced survival following intracarotid injection of sodium borocaptate with or without blood-brain barrier disruption

    SciTech Connect

    Yang, W.; Barth, R.F.; Rotaru, J.H.

    1997-02-01

    Sodium borocaptate (Na{sub 2}B{sub 12}H{sub 11}SH or BSH) has been used clinically for boron neutron capture therapy (BNCT) of patients with primary brain tumors. The purpose of the present study was to determine if tumor uptake of BSH and efficacy of BNCT could be enhanced in F98 glioma-bearing rats by intracarotid (i.c.) injection of the compound with or without blood-brain barrier disruption (BBB-D). 56 refs., 4 figs., 3 tabs.

  15. Laser Unlocks Blood-Brain Barrier for Chemotherapy, Study Shows

    MedlinePlus

    ... nlm.nih.gov/medlineplus/news/fullstory_157444.html Laser Unlocks Blood-Brain Barrier for Chemotherapy, Study Shows ... 24, 2016 WEDNESDAY, Feb. 24, 2016 (HealthDay News) -- Laser surgery can open the protective blood-brain barrier, ...

  16. The effect of ionizing radiation on the blood-brain-barrier (BBB): Considerations for the application of Boron Neutron Capture Therapy (BNCT) of brain tumors

    SciTech Connect

    Dorn, R.V. III; Spickard, J.H.; Griebenow, M.L.

    1988-01-01

    All methods of Boron Neutron Capture Therapy (BNCT) in use or envisioned for treatment of brain tumors have an element of ionizing radiation (incident and induced). This paper reviews data on the effects of ionizing radiation on the blood-brain-barrier (BBB) and the blood-tumor-barrier (BTB) and the potential impact of the effects on the delivery techniques of BNCT. The objectives are: review the available technique for BNCT of brain tumors; review the literature on experimental and human studies regarding the effects of ionizing radiation on the BBB; discuss the impact of these effects on the fractionization question for BNCT; and draw conclusions from that information. 22 refs., 4 tabs.

  17. The effects of ionizing radiation and dexamethasone on the blood-brain-barrier (BBB) and blood-tumor-barrier (BTB): Implications for boron neutron capture therapy (BNCT) of brain tumors

    SciTech Connect

    Dorn, R.V. III; Spickard, J.H.; Griebenow, M.L.

    1988-01-01

    Currently envisioned techniques for Boron Neutron Capture Therapy (BNCT) of brain tumors rely on the increased permeability of the blood-brain-barrier (BBB) (more specifically, the blood-tumor-barrier (BTB)) which occurs around the malignant tumor. As a result of this increased permeability, higher boron concentrations (Na/sub 2/B/sub 12/H/sub 11/SH) should be obtainable in the tumor than in the surrounding normal brain. The effects on the BBB and BTB by the ionizing component of this radiation and by the steroid dexamethasone (almost universally used in the clinical management of these patients) must be considered in the formulation of this treatment technique. 32 refs., 5 tabs.

  18. AIDS and the blood-brain barrier

    PubMed Central

    Ivey, Nathan S.; MacLean, Andrew G.; Lackner, Andrew A.

    2009-01-01

    The blood-brain barrier (BBB) plays a critical role in normal physiology of the central nervous system by regulating what reaches the brain from the periphery. The BBB also plays a major role in neurologic disease including neuropathologic sequelae associated with infection by human immunodeficiency virus (HIV) in humans and the closely related simian immunodeficiency virus (SIV) in macaques. In this review, we provide an overview of the function, structure and components of the BBB, followed by a more detailed discussion of the subcellular structures and regulation of the tight junction. We then discuss the ways in which HIV/SIV affects the BBB, largely through infection of monocytes/macrophages, and how infected macrophages crossing the BBB ultimately results in breakdown of the barrier. PMID:19306229

  19. The dynamic blood-brain barrier.

    PubMed

    Keaney, James; Campbell, Matthew

    2015-11-01

    With the endothelium as its central unit, the blood-brain barrier (BBB) is a complex multicellular structure separating the central nervous system (CNS) from the systemic circulation. Disruption of the BBB has now been implicated in a multitude of acute and chronic CNS disorders indicating the potentially devastating effects of BBB breakdown on brain function. However, the healthy BBB is not an impermeable wall, but rather a communication 'centre', responding to and passing signals between the CNS and blood. New studies are identifying BBB-specific transport pathways that tightly regulate the entry and exit of molecules to and from the brain. They are revealing a highly plastic barrier in which dynamic changes in BBB components like paracellular tight junction complexes can contribute to BBB maintenance. Here, we provide a succinct overview of the current state-of-play in BBB research and summarize novel findings into BBB regulation in homeostatic regulation of the brain. PMID:26277326

  20. Dissecting gene expression at the blood-brain barrier

    PubMed Central

    Huntley, Melanie A.; Bien-Ly, Nga; Daneman, Richard; Watts, Ryan J.

    2014-01-01

    The availability of genome-wide expression data for the blood-brain barrier is an invaluable resource that has recently enabled the discovery of several genes and pathways involved in the development and maintenance of the blood-brain barrier, particularly in rodent models. The broad distribution of published data sets represents a viable starting point for the molecular dissection of the blood-brain barrier and will further direct the discovery of novel mechanisms of blood-brain barrier formation and function. Technical advances in purifying brain endothelial cells, the key cell that forms the critical barrier, have allowed for greater specificity in gene expression comparisons with other central nervous system cell types, and more systematic characterizations of the molecular composition of the blood-brain barrier. Nevertheless, our understanding of how the blood-brain barrier changes during aging and disease is underrepresented. Blood-brain barrier data sets from a wider range of experimental paradigms and species, including invertebrates and primates, would be invaluable for investigating the function and evolution of the blood-brain barrier. Newer technologies in gene expression profiling, such as RNA-sequencing, now allow for finer resolution of transcriptomic changes, including isoform specificity and RNA-editing. As our field continues to utilize more advanced expression profiling in its ongoing efforts to elucidate the blood-brain barrier, including in disease and drug delivery, we will continue to see rapid advances in our understanding of the molecular mediators of barrier biology. We predict that the recently published data sets, combined with forthcoming genomic and proteomic blood-brain barrier data sets, will continue to fuel the molecular genetic revolution of blood-brain barrier biology. PMID:25414634

  1. Effects of Adrenal Cortical Steroids and Osmotic Blood-Brain Barrier Opening on Methotrexate Delivery to Gliomas in the Rodent: The Factor of the Blood-Brain Barrier

    NASA Astrophysics Data System (ADS)

    Neuwelt, Edward A.; Barnett, Peggy A.; Bigner, Darrell D.; Frenkel, Eugene P.

    1982-07-01

    The effect of adrenal cortical steroids and osmotic blood-brain barrier modification on methotrexate delivery to normal and glioma-bearing rats was studied. In animals with the avian sarcoma virus-induced glioma, osmotic blood-brain barrier modification resulted in significantly increased delivery of methotrexate to the tumor-bearing hemisphere (including the tumor, the brain around the tumor, and the brain distant to the tumor), compared to the nonmodified hemisphere or to control animals. The administration of adrenal steroids, followed by intracarotid methotrexate, resulted in slightly decreased chemotherapeutic agent (methotrexate) delivery to the tumor, the brain around the tumor, and the brain distant to the tumor. When adrenal steroids were given prior to barrier modification and methotrexate therapy, the level of methotrexate was significantly less in the tumor. These studies provide evidence that the blood-brain barrier exists in tumors and is a factor in drug delivery to tumors. Steroid administration greatly interferes with the enhancement of drug delivery to tumors that can be achieved with osmotic blood-brain barrier modification.

  2. Peptides and the blood-brain barrier.

    PubMed

    Banks, William A

    2015-10-01

    The demonstration that peptides and regulatory proteins can cross the blood-brain barrier (BBB) is one of the major contributions of Dr. Abba J. Kastin. He was the first to propose that peptides could cross the BBB, the first to show that an endogenous peptide did so, and the first to describe a saturable transport system at the BBB for peptides. His work shows that in crossing the BBB, peptides and regulatory proteins act as informational molecules, informing the brain of peripheral events. Brain-to-blood passage helps to control levels of peptides with the brain and can deliver information in the brain-to-blood direction. He showed that the transporters for peptides and proteins are not static, but respond to developmental and physiological changes and are affected by disease states. As such, the BBB is adaptive to the needs of the CNS, but when that adaption goes awry, the BBB can be a cause of disease. The mechanisms by which peptides and proteins cross the BBB offer opportunities for drug delivery of these substances or their analogs to the brain in the treatment of diseases of the central nervous system. PMID:25805003

  3. Neurosurgical Techniques for Disruption of the Blood-Brain Barrier for Glioblastoma Treatment.

    PubMed

    Rodriguez, Analiz; Tatter, Stephen B; Debinski, Waldemar

    2015-01-01

    The blood-brain barrier remains a main hurdle to drug delivery to the brain. The prognosis of glioblastoma remains grim despite current multimodal medical management. We review neurosurgical technologies that disrupt the blood-brain barrier (BBB). We will review superselective intra-arterial mannitol infusion, focused ultrasound, laser interstitial thermotherapy, and non-thermal irreversible electroporation (NTIRE). These technologies can lead to transient BBB and blood-brain tumor barrier disruption and allow for the potential of more effective local drug delivery. Animal studies and preliminary clinical trials show promise for achieving this goal. PMID:26247958

  4. Blood-brain barrier and new approaches to brain drug delivery.

    PubMed Central

    Pardridge, W. M.; Boado, R. J.; Black, K. L.; Cancilla, P. A.

    1992-01-01

    Morbidity caused by brain dysfunction affects more than 50 million persons in the United States. Although new neuropharmaceuticals have the potential for treating specific brain diseases, they may not effectively enter brain from blood. Safe strategies are needed for drug delivery through the brain capillary wall, which makes up the blood-brain barrier in vivo. Two of these strategies are reviewed, as are related new developments in the molecular and cell biology of the brain capillary endothelium. The production of chimeric peptides represents a physiologic-based strategy for drug delivery. It entails the covalent coupling of the neuropharmaceutical to a brain transport vector, allowing transportation through the blood-brain barrier. Another strategy is biochemical opening of the blood-brain barrier: intracarotid leukotriene infusion is a method for selectively increasing blood-brain barrier permeability in brain tumors without affecting barrier permeability in normal brain tissue. Images PMID:1595245

  5. Improved anti-tumor effect of liposomal doxorubicin after targeted blood-brain barrier disruption by MRI-guided focused ultrasound in rat glioma

    PubMed Central

    Treat, Lisa H.; McDannold, Nathan; Zhang, Yongzhi; Vykhodtseva, Natalia; Hynynen, Kullervo

    2012-01-01

    The blood-brain barrier (BBB) inhibits the entry of the majority of chemotherapeutic agents into the brain. Previous studies have illustrated the feasibility of drug delivery across the BBB using focused ultrasound (FUS) and microbubbles. Here, we investigated the effect of FUS-enhanced delivery of doxorubicin on survival in rats with and 9L gliosarcoma cells inoculated in the brain. Each rat received either: (1) no treatment (control; N=11), (2) FUS only (N=9), (3) i.v. liposomal doxorubicin (DOX only; N=17), or (4) FUS with concurrent i.v. injections of liposomal doxorubicin (FUS+DOX; N=20). Post-treatment MRI showed that FUS+DOX reduced tumor growth compared to DOX only. Further, we observed a modest but significant increase in median survival time after a single treatment FUS+DOX treatment (p=0.0007), whereas neither DOX nor FUS had any significant impact on survival on its own. These results suggest that combined ultrasound-mediated BBB disruption may significantly increase the antineoplastic efficacy of liposomal doxorubicin in the brain. PMID:22818878

  6. Controlling ferrofluid permeability across the blood-brain barrier model

    NASA Astrophysics Data System (ADS)

    Shi, Di; Sun, Linlin; Mi, Gujie; Sheikh, Lubna; Bhattacharya, Soumya; Nayar, Suprabha; Webster, Thomas J.

    2014-02-01

    In the present study, an in vitro blood-brain barrier model was developed using murine brain endothelioma cells (b.End3 cells). Confirmation of the blood-brain barrier model was completed by examining the permeability of FITC-Dextran at increasing exposure times up to 96 h in serum-free medium and comparing such values with values from the literature. After such confirmation, the permeability of five novel ferrofluid (FF) nanoparticle samples, GGB (ferrofluids synthesized using glycine, glutamic acid and BSA), GGC (glycine, glutamic acid and collagen), GGP (glycine, glutamic acid and PVA), BPC (BSA, PEG and collagen) and CPB (collagen, PVA and BSA), was determined using this blood-brain barrier model. All of the five FF samples were characterized by zeta potential to determine their charge as well as TEM and dynamic light scattering for determining their hydrodynamic diameter. Results showed that FF coated with collagen passed more easily through the blood-brain barrier than FF coated with glycine and glutamic acid based on an increase of 4.5% in permeability. Through such experiments, diverse magnetic nanomaterials (such as FF) were identified for: (1) MRI use since they were less permeable to penetrate the blood-brain barrier to avoid neural tissue toxicity (e.g. GGB) or (2) brain drug delivery since they were more permeable to the blood-brain barrier (e.g. CPB).

  7. Osmotic blood-brain barrier disruption: CT and radionuclide imaging

    SciTech Connect

    Roman-Goldstein, S.; Clunie, D.A.; Stevens, J.; Hogan, R.; Monard, J.; Ramsey, F.; Neuwelt, E.A.

    1994-03-01

    The purpose of this study was to compare CT and radionuclide imaging of osmotic blood-brain barrier disruption, and to develop a quantitative method for imaging osmotic blood-brain barrier disruption and to see if iopamidol could be safety given intravenously in conjunction with blood-brain barrier disruption. Forty-five blood-brain barrier disruption procedures were imaged with CT and radionuclide scans. The scans were evaluated with visual and quantitative scales. Patients were observed for adverse effects after blood-brain barrier disruption. There was a 4% rate of seizures in this study. There was good agreement between visual CT and radionuclide grading systems. Quantitative disruption did not add useful information to visual interpretations. Nonionic iodine-based contrast medium has a lower incidence of seizures when injected intravenously in conjunction with osmotic blood-brain barrier disruption than ionic contrast material. Contrast-enhanced CT is the preferred method to image disruption because it has better spatial resolution than radionuclide techniques. 34 refs., 4 figs., 6 tabs.

  8. The blood-brain barrier: an engineering perspective

    PubMed Central

    Wong, Andrew D.; Ye, Mao; Levy, Amanda F.; Rothstein, Jeffrey D.; Bergles, Dwight E.; Searson, Peter C.

    2013-01-01

    It has been more than 100 years since Paul Ehrlich reported that various water-soluble dyes injected into the circulation did not enter the brain. Since Ehrlich's first experiments, only a small number of molecules, such as alcohol and caffeine have been found to cross the blood-brain barrier, and this selective permeability remains the major roadblock to treatment of many central nervous system diseases. At the same time, many central nervous system diseases are associated with disruption of the blood-brain barrier that can lead to changes in permeability, modulation of immune cell transport, and trafficking of pathogens into the brain. Therefore, advances in our understanding of the structure and function of the blood-brain barrier are key to developing effective treatments for a wide range of central nervous system diseases. Over the past 10 years it has become recognized that the blood-brain barrier is a complex, dynamic system that involves biomechanical and biochemical signaling between the vascular system and the brain. Here we reconstruct the structure, function, and transport properties of the blood-brain barrier from an engineering perspective. New insight into the physics of the blood-brain barrier could ultimately lead to clinical advances in the treatment of central nervous system diseases. PMID:24009582

  9. Gliomas and the vascular fragility of the blood brain barrier

    PubMed Central

    Dubois, Luiz Gustavo; Campanati, Loraine; Righy, Cassia; D’Andrea-Meira, Isabella; Spohr, Tania Cristina Leite de Sampaio e; Porto-Carreiro, Isabel; Pereira, Claudia Maria; Balça-Silva, Joana; Kahn, Suzana Assad; DosSantos, Marcos F.; Oliveira, Marcela de Almeida Rabello; Ximenes-da-Silva, Adriana; Lopes, Maria Celeste; Faveret, Eduardo; Gasparetto, Emerson Leandro; Moura-Neto, Vivaldo

    2014-01-01

    Astrocytes, members of the glial family, interact through the exchange of soluble factors or by directly contacting neurons and other brain cells, such as microglia and endothelial cells. Astrocytic projections interact with vessels and act as additional elements of the Blood Brain Barrier (BBB). By mechanisms not fully understood, astrocytes can undergo oncogenic transformation and give rise to gliomas. The tumors take advantage of the BBB to ensure survival and continuous growth. A glioma can develop into a very aggressive tumor, the glioblastoma (GBM), characterized by a highly heterogeneous cell population (including tumor stem cells), extensive proliferation and migration. Nevertheless, gliomas can also give rise to slow growing tumors and in both cases, the afflux of blood, via BBB is crucial. Glioma cells migrate to different regions of the brain guided by the extension of blood vessels, colonizing the healthy adjacent tissue. In the clinical context, GBM can lead to tumor-derived seizures, which represent a challenge to patients and clinicians, since drugs used for its treatment must be able to cross the BBB. Uncontrolled and fast growth also leads to the disruption of the chimeric and fragile vessels in the tumor mass resulting in peritumoral edema. Although hormonal therapy is currently used to control the edema, it is not always efficient. In this review we comment the points cited above, considering the importance of the BBB and the concerns that arise when this barrier is affected. PMID:25565956

  10. [Blood-brain barrier transport of opioid analgesics].

    PubMed

    Suzuki, Toyofumi

    2011-01-01

    Opioid analgesics exhibit cationic properties under physiological conditions, and the mechanism underlying permeation of the blood-brain barrier thus cannot be fully explained by simple diffusion alone. Various types of transporters that exhibit substrate specificity are localized on the blood-brain barrier, and play a role in transporting substances from circulating blood and from brain interstitial fluid. Progress is being made in explaining the mechanisms, functions, and physiological roles of polyspecific organic cation transporters, but little evidence has indicated that these previously identified organic cation transporters are involved in the transport of opioid analgesics across the blood-brain barrier. Consequently, clarifying the role of transporters in the distribution of opioid analgesics into the brain and determining their transport molecule will not only provide clues to effective drug delivery to the brain, but will also contribute to optimizing pain relief treatment, and by extension play a role in drug discovery for analgesics. Currently there are enthusiastic discussions in the literature regarding the existence of putative transporters involved in the transport of opioid analgesics across the blood-brain barrier. This review article introduces the results of our research as well as recent findings on the involvement of transporters in the blood-brain barrier transport of opioid analgesics such as morphine, morphine metabolites, oxycodone, fentanyl, codeine, and pentazocine. PMID:21963971

  11. The blood-brain barrier and methamphetamine: open sesame?

    PubMed Central

    Turowski, Patric; Kenny, Bridget-Ann

    2015-01-01

    The chemical and electrical microenvironment of neurons within the central nervous system is protected and segregated from the circulation by the vascular blood–brain barrier. This barrier operates on the level of endothelial cells and includes regulatory crosstalk with neighboring pericytes, astrocytes, and neurons. Within this neurovascular unit, the endothelial cells form a formidable, highly regulated barrier through the presence of inter-endothelial tight junctions, the absence of fenestrations, and the almost complete absence of fluid-phase transcytosis. The potent psychostimulant drug methamphetamine transiently opens the vascular blood–brain barrier through either or both the modulation of inter-endothelial junctions and the induction of fluid-phase transcytosis. Direct action of methamphetamine on the vascular endothelium induces acute opening of the blood-brain barrier. In addition, striatal effects of methamphetamine and resultant neuroinflammatory signaling can indirectly lead to chronic dysfunction of the blood-brain barrier. Breakdown of the blood-brain barrier may exacerbate the neuronal damage that occurs during methamphetamine abuse. However, this process also constitutes a rare example of agonist-induced breakdown of the blood-brain barrier and the adjunctive use of methamphetamine may present an opportunity to enhance delivery of chemotherapeutic agents to the underlying neural tissue. PMID:25999807

  12. Toxoplasma gondii and the blood-brain barrier

    PubMed Central

    Feustel, Sabrina M.; Meissner, Markus; Liesenfeld, Oliver

    2012-01-01

    Infection with the protozoan parasite Toxoplasma gondii is characterized by asymptomatic latent infection in the central nervous system and skeletal muscle tissue in the majority of immunocompentent individuals. Life-threatening reactivation of the infection in immunocompromized patients originates from rupture of Toxoplasma cysts in the brain. While major progress has been made in our understanding of the immunopathogenesis of infection the mechanism(s) of neuroinvasion of the parasite remains poorly understood. The present review presents the current understanding of blood-brain barrier (patho)physiology and the interaction of Toxoplasma gondii with cells of the blood-brain barrier. PMID:22460645

  13. Barrier mechanisms in the Drosophila blood-brain barrier

    PubMed Central

    Hindle, Samantha J.; Bainton, Roland J.

    2014-01-01

    The invertebrate blood-brain barrier (BBB) field is growing at a rapid pace and, in recent years, studies have shown a physiologic and molecular complexity that has begun to rival its vertebrate counterpart. Novel mechanisms of paracellular barrier maintenance through G-protein coupled receptor signaling were the first demonstrations of the complex adaptive mechanisms of barrier physiology. Building upon this work, the integrity of the invertebrate BBB has recently been shown to require coordinated function of all layers of the compound barrier structure, analogous to signaling between the layers of the vertebrate neurovascular unit. These findings strengthen the notion that many BBB mechanisms are conserved between vertebrates and invertebrates, and suggest that novel findings in invertebrate model organisms will have a significant impact on the understanding of vertebrate BBB functions. In this vein, important roles in coordinating localized and systemic signaling to dictate organism development and growth are beginning to show how the BBB can govern whole animal physiologies. This includes novel functions of BBB gap junctions in orchestrating synchronized neuroblast proliferation, and of BBB secreted antagonists of insulin receptor signaling. These advancements and others are pushing the field forward in exciting new directions. In this review, we provide a synopsis of invertebrate BBB anatomy and physiology, with a focus on insights from the past 5 years, and highlight important areas for future study. PMID:25565944

  14. Simplified, noninvasive PET measurement of blood-brain barrier permeability

    SciTech Connect

    Iannotti, F.; Fieschi, C.; Alfano, B.; Picozzi, P.; Mansi, L.; Pozzilli, C.; Punzo, A.; Del Vecchio, G.; Lenzi, G.L.; Salvatore, M.

    1987-05-01

    Blood-brain barrier (BBB) permeability to (/sup 68/Ga)EDTA was measured by positron emission tomography (PET) in four normal volunteers and in 11 patients with brain tumors. A unidirectional transfer constant, Ki, was calculated applying multiple-time graphical analysis (MTGA). This method allows the detection of backflux from brain to blood and, by generalization, the measurement of the constant Kb (brain to blood). Furthermore, the need for an independent measurement of the intravascular tracer is obviated: MTGA itself provides an estimate of the cerebral plasma volume (Vp). In the four normal volunteers the Ki was 3.0 +/- 0.8 X 10(-4) ml g-1 min-1 (mean +/- SD) and the Vp 0.034 +/- 0.007 ml g-1. A net increase in Ki up to a maximum of 121.0 X 10(-4) ml g-1 min-1 (correspondent value of Kb = 0.025 min-1) as well as an increase of Vp was observed in malignant tumors. The input function was calculated using both the (/sup 68/Ga)EDTA concentration in sequential arterial blood samples and, noninvasively, the activity derived from the superior sagittal sinus image. The values of Ki and Vp from these two calculations were in good agreement. The application of MTGA to PET permits the evaluation of passage of substances across the BBB without making assumptions about the compartments in which the tracer distributes.

  15. Mathematical modelling of blood-brain barrier failure and edema

    NASA Astrophysics Data System (ADS)

    Waters, Sarah; Lang, Georgina; Vella, Dominic; Goriely, Alain

    2015-11-01

    Injuries such as traumatic brain injury and stroke can result in increased blood-brain barrier permeability. This increase may lead to water accumulation in the brain tissue resulting in vasogenic edema. Although the initial injury may be localised, the resulting edema causes mechanical damage and compression of the vasculature beyond the original injury site. We employ a biphasic mixture model to investigate the consequences of blood-brain barrier permeability changes within a region of brain tissue and the onset of vasogenic edema. We find that such localised changes can indeed result in brain tissue swelling and that the type of damage that results (stress damage or strain damage) depends on the ability of the brain to clear edema fluid.

  16. Cerebrospinal fluid aquaporin-4-immunoglobulin G disrupts blood brain barrier.

    PubMed

    Asgari, Nasrin; Berg, Carsten Tue; Mørch, Marlene Thorsen; Khorooshi, Reza; Owens, Trevor

    2015-08-01

    To clarify the significance of immunoglobulin G autoantibody specific for the astrocyte water channel aquaporin-4 in cerebrospinal fluid, aquaporin-4-immunoglobulin G from a neuromyelitis optica patient was administered intrathecally to naïve mice, and the distribution and pathogenic impact was evaluated. A distinct distribution pattern of aquaporin-4-immunoglobulin G deposition was observed in the subarachnoid and subpial spaces where vessels penetrate the brain parenchyma, via a paravascular route with intraparenchymal perivascular deposition. Perivascular astrocyte-destructive lesions were associated with blood-borne horseradish peroxidase leakage indicating blood-brain barrier breakdown. The cerebrospinal fluid aquaporin-4-immunoglobulin G therefore distributes widely in brain to initiate astrocytopathy and blood-brain barrier breakdown. PMID:26339679

  17. Enhanced delivery of etoposide across the blood-brain barrier to restrain brain tumor growth using melanotransferrin antibody- and tamoxifen-conjugated solid lipid nanoparticles.

    PubMed

    Kuo, Yung-Chih; Wang, I-Hsin

    2016-08-01

    Melanotransferrin antibody (MA) and tamoxifen (TX) were conjugated on etoposide (ETP)-entrapped solid lipid nanoparticles (ETP-SLNs) to target the blood-brain barrier (BBB) and glioblastom multiforme (GBM). MA- and TX-conjugated ETP-SLNs (MA-TX-ETP-SLNs) were used to infiltrate the BBB comprising a monolayer of human astrocyte-regulated human brain-microvascular endothelial cells (HBMECs) and to restrain the proliferation of malignant U87MG cells. TX-grafted ETP-SLNs (TX-ETP-SLNs) significantly enhanced the BBB permeability coefficient for ETP and raised the fluorescent intensity of calcein-AM when compared with ETP-SLNs. In addition, surface MA could increase the BBB permeability coefficient for ETP about twofold. The viability of HBMECs was higher than 86%, suggesting a high biocompatibility of MA-TX-ETP-SLNs. Moreover, the efficiency in antiproliferation against U87MG cells was in the order of MA-TX-ETP-SLNs  >  TX-ETP-SLNs  >  ETP-SLNs  >  SLNs. The capability of MA-TX-ETP-SLNs to target HBMECs and U87MG cells during internalization was verified by immunochemical staining of expressed melanotransferrin. MA-TX-ETP-SLNs can be a potent pharmacotherapy to deliver ETP across the BBB to GBM. PMID:26768307

  18. The disturbed blood-brain barrier in human glioblastoma.

    PubMed

    Wolburg, Hartwig; Noell, Susan; Fallier-Becker, Petra; Mack, Andreas F; Wolburg-Buchholz, Karen

    2012-01-01

    The aim of this article is to describe alterations of the blood-brain barrier (BBB) in gliomas. The main clinical problem of human gliomas is the edematous swelling and the dramatic increase of intracerebral pressure, also compromising healthy areas of the brain. According to our concept, one of the main reasons on the cellular level for these clinical problems is the loss or reduction of astroglial polarity. Astroglial polarity means the specific accumulation of potassium and water channels in the superficial and perivascular astroglial endfeet membranes. The most important water channel in the CNS is the astroglial water channel protein aquaporin-4 (AQP4) which is arranged in a morphologically spectacular way, the so-called orthogonal arrays of particles (OAPs) to be observed in freeze-fracture replicas. In brain tumors, but also under conditions of trauma or inflammation, these OAPs are redistributed to membrane domains apart from endfeet areas. Probably, this dislocation might be due to the degradation of the proteoglycan agrin by the matrix metalloproteinase 3 (MMP3). Agrin binds to the dystrophin-dystroglycan-complex (DDC), which in turn is connected to AQP4. As a consequence, agrin loss may lead to a redistribution of AQP4 and a compromised directionality of water transport out of the cell, finally to cytotoxic edema. This in turn is hypothesized to lead to a breakdown of the BBB characterized by disturbed tight junctions, and thus to the development of vasogenic edema. However, the mechanism how the loss of polarity is related to the disturbance of microvascular tight junctions is completely unknown so far. PMID:22387049

  19. Effects of microwave radiation on the blood-brain barrier

    SciTech Connect

    Ward, T.R.; Ali, J.S.; Long, M.D.

    1986-05-01

    The authors attempted to repeat a portion of the study by Oscar and Hawkins in which pulsed and continuous-wave microwave radiation increased permeation of labeled tracers through the blood-brain barrier. At the SAR used (0.1 W/kg) the calculated average brain temperature rise is less than 0.1C. The authors found no changes in permeation; however, there were differences in experimental conditions, including type of tracers, frequency and microwave field configuration. It is possible but unlikely that one of these differences is responsible for the apparent discrepancy in results.

  20. Peptides at the blood brain barrier: Knowing me knowing you.

    PubMed

    Davis, Thomas P; Abbruscato, Thomas J; Egleton, Richard D

    2015-10-01

    When the Davis Lab was first asked to contribute to this special edition of Peptides to celebrate the career and influence of Abba Kastin on peptide research, it felt like a daunting task. It is difficult to really understand and appreciate the influence that Abba has had, not only on a generation of peptide researchers, but also on the field of blood brain barrier (BBB) research, unless you lived it as we did. When we look back at our careers and those of our former students, one can truly see that several of Abba's papers played an influential role in the development of our personal research programs. PMID:25937599

  1. Maternal antibodies and developing blood-brain barrier.

    PubMed

    Kowal, Czeslawa; Athanassiou, Andrew; Chen, Huiyi; Diamond, Betty

    2015-12-01

    We briefly review the protective role of maternal antibodies during fetal development and at early postnatal stages. We describe antibody delivery to fetuses, particularly in the context of the developing blood-brain barrier (BBB), and present the essential concepts regarding the adult BBB, together with existing information on the prenatal developing BBB. We focus on maternal antibody transfer to the developing brain and the consequences of the presence of pathogenic antibodies at early stages of brain development on subsequent brain dysfunction. PMID:26507553

  2. SyM-BBB: A Microfluidic Blood Brain Barrier Model

    PubMed Central

    Prabhakarpandian, Balabhaskar; Shen, Ming-Che; Nichols, Joseph B.; Mills, Ivy R.; Sidoryk-Wegrzynowicz, Marta; Aschner, Michael; Pant, Kapil

    2013-01-01

    Current techniques for mimicking the Blood-Brain Barrier (BBB) largely use incubation chambers (Transwell) separated with a filter and matrix coating to represent and to study barrier permeability. These devices have several critical shortcomings; (a) they do not reproduce critical microenvironmental parameters, primarily anatomical size or hemodynamic shear stress, (b) they often do not provide real-time visualization capability, and (c) they require a large amount of consumables. To overcome these limitations, we have developed a microfluidics based Synthetic Microvasculature model of the Blood-Brain Barrier (SyM-BBB). The SyM-BBB platform is comprised of a plastic, disposable and optically clear microfluidic chip with a microcirculation sized two-compartment chamber. The chamber is designed in such a way as to permit the realization of side-by-side apical and basolateral compartments, thereby simplifying fabrication and facilitating integration with standard instrumentation. The individually addressable apical side is seeded with endothelial cells and the basolateral side can support neuronal cells or conditioned media. In the present study, an immortalized Rat Brain Endothelial cell line (RBE4) was cultured in SyM-BBB with a perfusate of Astrocyte Conditioned Media (ACM). Biochemical analysis showed upregulation of tight junction molecules while permeation studies showed an intact BBB. Finally, transporter assay was successfully demonstrated in SyM-BBB indicating a functional model. PMID:23344641

  3. PHYSIOLOGY AND PATHOPHYSIOLOGY OF THE BLOOD BRAIN BARRIER

    PubMed Central

    McCaffrey, Gwen; Davis, Thomas P.

    2012-01-01

    The blood-brain barrier (BBB) is a physical and metabolic barrier that separates the CNS from the peripheral circulation. CNS drug delivery across the BBB is challenging, primarily due to the physical restriction of paracellular diffusion between the endothelial cells that comprise the microvessels of the BBB and the activity of efflux transporters that quickly expel back into the capillary lumen a wide variety of xenobiotics. Therapeutic manipulation of protein trafficking is emerging as a novel means of modulating protein function, and in this mini-review, the targeting of the trafficking of two key BBB proteins, P-glycoprotein and occludin, is presented as a novel, reversible means of optimizing CNS drug delivery. PMID:23138008

  4. Optical imaging to map blood-brain barrier leakage

    NASA Astrophysics Data System (ADS)

    Jaffer, Hayder; Adjei, Isaac M.; Labhasetwar, Vinod

    2013-11-01

    Vascular leakage in the brain is a major complication associated with brain injuries and certain pathological conditions due to disruption of the blood-brain barrier (BBB). We have developed an optical imaging method, based on excitation and emission spectra of Evans Blue dye, that is >1000-fold more sensitive than conventional ultraviolet spectrophotometry. We used a rat thromboembolic stroke model to validate the usefulness of our method for vascular leakage. Optical imaging data show that vascular leakage varies in different areas of the post-stroke brain and that administering tissue plasminogen activator causes further leakage. The new method is quantitative, simple to use, requires no tissue processing, and can map the degree of vascular leakage in different brain locations. The high sensitivity of our method could potentially provide new opportunities to study BBB leakage in different pathological conditions and to test the efficacy of various therapeutic strategies to protect the BBB.

  5. Extracellular vesicles of the blood-brain barrier

    PubMed Central

    András, Ibolya E; Toborek, Michal

    2016-01-01

    Extracellular vesicles (ECV), like exosomes, gained recently a lot of attention as potentially playing a significant role in neurodegenerative diseases, particularly in Aβ pathology. While there are a lot of reports on ECV/exosomes derived from a variety of cell types, there is limited information on ECV/exosomes originated from brain microvascular endothelial cells forming the blood-brain barrier (BBB). In this review, we summarize the literature data on brain endothelial ECV/exosomes and present our own data on BBB-derived ECV and their possible involvement in the brain's Aβ pathology. We propose that ECV/exosome release from brain endothelial cells associated with Aβ affects different cells of the neurovascular unit and may be an important contributor to the Aβ deposition in the central nervous system. PMID:27141419

  6. How Cryptococcus interacts with the blood-brain barrier.

    PubMed

    Tseng, Hsiang-Kuang; Huang, Tseng-Yu; Wu, Alice Ying-Jung; Chen, Hsin-Hong; Liu, Chang-Pan; Jong, Ambrose

    2015-01-01

    Cryptococcus demonstrates predilection for invasion of the brain, but the mechanism by which Cryptococcus crosses the blood-brain barrier (BBB) to cause brain invasion is largely unknown. In order for Cryptococcus to cross the BBB, there must be a way to either cross human brain microvascular endothelial cells, which are the main constitute of the BBB, or go in between tight junctions. Recent evidence of human brain microvascular endothelial cell responses to transcellular brain invasions includes membrane rearrangements, intracellular signaling pathways and cytoskeletal activations. Several Cryptococcal genes related to the traversal of BBB have been identified, including CPS1, ITR1a, ITR3c, PLB1, MPR1, FNX1 and RUB1. In addition, Cryptococcus neoformans-derived microvesicles may contribute to cryptococcal brain invasion. Paracellularly, Cryptococcus may traverse across BBB using either routes utilizing plasmin, ammonia or macrophages in a Trojan horse mechanism. PMID:26437710

  7. Blood-brain barrier in acute liver failure

    PubMed Central

    Nguyen, Justin H.

    2011-01-01

    Brain edema remains a challenging obstacle in the management of acute liver failure (ALF). Cytotoxic mechanisms associated with brain edema have been well recognized, but evidence for vasogenic mechanisms in the pathogenesis of brain edema in ALF has been lacking. Recent reports have not only shown a role of matrix metalloproteinase-9 in the pathogenesis of brain edema in experimental ALF but have also found significant alterations in the tight junction elements including occludin and claudin-5, suggesting a vasogenic injury in the blood-brain barrier (BBB) integrity. This article reviews and explores the role of the paracellular tight junction proteins in the increased selective BBB permeability that leads to brain edema in ALF. PMID:22100566

  8. Blood-brain barrier and neuro-AIDS.

    PubMed

    Zhang, Y-L; Ouyang, Y-B; Liu, L-G; Chen, D-X

    2015-12-01

    Neuro-AIDS is becoming a major health problem among AIDS patients who experience improved survival under combined antiretroviral therapy (cART). Neuronal injury and loss are the critical issues of neuro-AIDS that need the entry of HIV into the central nervous system (CNS) via peripheral infected monocyte/macrophage carriers or viral direct penetration of blood-brain barrier (BBB). The mechanisms of HIV enhancing BBB permeability and entering CNS and the effect of drug abuse in HIV traffic across BBB are discussed. In addition, the current anti-HIV drugs, although they are effective in reducing plasma viral level, cannot eradicate the viruses completely from CNS. The possible mechanism of BBB hindrance and anti-HIV drug efflux by transport proteins, and general methods used to deliver antiretroviral drugs into brain are also discussed. PMID:26744885

  9. Bypassing the blood-brain barrier: delivery of therapeutic agents by macrophages

    NASA Astrophysics Data System (ADS)

    Hirschberg, Henry; Baek, Seung-Kuk; Kwon, Young Jik; Sun, Chung-Ho; Madsen, Steen J.

    2010-02-01

    Introduction: Failure to eradicate infiltrating glioma cells using conventional treatment regimens results in tumor recurrence and is responsible for the dismal prognosis of patients with glioblastoma multiforme (GBM). This is due to the fact that these migratory cells are protected by the blood-brain barrier (BBB) and the blood brain tumor barrier (BBTB) which prevents the delivery of most anti-cancer agents. We have evaluated the ability of monocytes/macrophages (Mo/Ma) to cross the BBB in rats. This will permit access of anti-cancer agents such as nanoparticles to effectively target the infiltrating tumor cells, and potentially improve the treatment effectiveness for malignant gliomas. Materials and Methods: The infiltration of Mo/Ma into brain tumor spheroids in vitro was determined using fluorescent stained Mo/Ma. Tumors were also established in the brains of inbred rats and ALA-PDT was given 18 days following tumor induction. The degredation of the BBTB and quantification of the number of infiltrating Mo/Ma was examined on histological sections from removed brains. Results & Conclusion: PDT was highly effective in locally opening the BBTB and inducing macrophage migration into the irradiated portions of brain tumors.

  10. M2698 is a potent dual-inhibitor of p70S6K and Akt that affects tumor growth in mouse models of cancer and crosses the blood-brain barrier

    PubMed Central

    Machl, Andreas; Wilker, Erik W; Tian, Hui; Liu, Xiaohong; Schroeder, Patricia; Clark, Anderson; Huck, Bayard R

    2016-01-01

    Dysregulated PI3K/Akt/mTOR (PAM) pathway signaling occurs in ~30% of human cancers, making it a rational target for new therapies; however, the effectiveness of some PAM pathway inhibitors, such as mTORC rapalogs, may be compromised by a compensatory feedback loop leading to Akt activation. In this study, the p70S6K/Akt dual inhibitor, M2698 (previously MSC2363318A), was characterized as a potential anti-cancer agent through examination of its pharmacokinetic, pharmacodynamic and metabolic properties, and anti-tumor activity. M2698 was highly potent in vitro (IC50 1 nM for p70S6K, Akt1 and Akt3 inhibition; IC50 17 nM for pGSK3β indirect inhibition) and in vivo (IC50 15 nM for pS6 indirect inhibition), and relatively selective (only 6/264 kinases had an IC50 within 10-fold of p70S6K). Orally administered M2698 crossed the blood-brain barrier in rats and mice, with brain tumor exposure 4-fold higher than non-disease brain. Dose-dependent inhibition of target substrate phosphorylation was observed in vitro and in vivo, indicating that M2698 blocked p70S6K to provide potent PAM pathway inhibition while simultaneously targeting Akt to overcome the compensatory feedback loop. M2698 demonstrated dose-dependent tumor growth inhibition in mouse xenograft models derived from PAM pathway-dysregulated human triple-negative (MDA-MB-468) and Her2-expressing breast cancer cell lines (MDA-MB-453 and JIMT-1), and reduced brain tumor burden and prolonged survival in mice with orthotopically implanted U251 glioblastoma. These findings highlight M2698 as a promising PAM pathway inhibitor whose unique mechanism of action and capacity to pass the blood-brain barrier warrant clinical investigation in cancers with PAM pathway dysregulation, and those with central nervous system involvement. PMID:27186432

  11. Protection of the blood-brain barrier by hypercapnia during acute hypertension

    SciTech Connect

    Baumbach, G.L.; Mayhan, W.G.; Heistad, D.D.

    1986-08-01

    The purpose of this study was to examine effects of hypercapnia on susceptibility of the blood-brain barrier to disruption during acute hypertension. Two methods were used to test the hypothesis that cerebral vasodilation during hypercapnia increases disruption of the blood-brain barrier. First, permeability of the blood-brain barrier was measured in anesthetized cats with SVI-labeled serum albumin. Severe hypertension markedly increased permeability of the blood-brain barrier during normocapnia, but not during hypercapnia. The protective effect of hypercapnia was not dependent on sympathetic nerves. Second, in anesthetized rats, permeability of the barrier was quantitated by clearance of fluorescent dextran. Disruption of the blood-brain barrier during hypertension was decreased by hypercapnia. Because disruption of the blood-brain barrier occurred primarily in pial venules, the authors also measured pial venular diameter and pressure. Acute hypertension increased pial venular pressure and diameter in normocapnic rats. Hypercapnia alone increased pial venular pressure and pial venular diameter, and acute hypertension during hypercapnia further increased venular pressure. The magnitude of increase in pial venular pressure during acute hypertension was significantly less in hypercapnic than in normocapnic rats. They conclude that hypercapnia protects the blood-brain barrier. Possible mechanisms of this effect include attenuation of the incremental increase in pial venular pressure by hypercapnia or a direct effect on the blood-brain barrier not related to venous pressure.

  12. Current concepts of blood-brain barrier development.

    PubMed

    Liebner, Stefan; Czupalla, Cathrin J; Wolburg, Hartwig

    2011-01-01

    Homeostasis of the central nervous system (CNS) microenvironment is essential for its normal function and is maintained by the blood-brain barrier (BBB). The BBB proper is made up of endothelial cells (ECs) interconnected by tight junctions (TJs) that reveal a unique morphology and biochemical composition of the body's vasculature. In this article, we focus on developmental aspects of the BBB and describe morphological as well as molecular special features of the neuro-vascular unit (NVU) involved in barrier induction. Recently, we and others identified the Wnt/b-catenin pathway as crucial for brain angiogenesis, TJ and BBB formation. Based on these findings we discuss other pathways and molecular interactions for BBB establishment and maintenance. At the morphological level, our concept favors a major role for polarized astrocytes (ACs) therein. Orthogonal arrays of particles (OAPs) that are the morphological correlate of the water channel protein aquaporin-4 (AQP4) are specifically formed in the membrane of the AC endfoot. The polarized AC endfoot and hence OAPs are dependent on agrin and dystroglycan, of which agrin is a developmentally regulated extracellular matrix (ECM) component. Understanding the mechanisms leading to BBB development will be key to the understanding of barrier maintenance that is crucial for, but frequently disturbed, in the diseased adult brain. PMID:21769778

  13. Astrocytic modulation of blood brain barrier: perspectives on Parkinson's disease.

    PubMed

    Cabezas, Ricardo; Avila, Marcos; Gonzalez, Janneth; El-Bachá, Ramon Santos; Báez, Eliana; García-Segura, Luis Miguel; Jurado Coronel, Juan Camilo; Capani, Francisco; Cardona-Gomez, Gloria Patricia; Barreto, George E

    2014-01-01

    The blood-brain barrier (BBB) is a tightly regulated interface in the Central Nervous System (CNS) that regulates the exchange of molecules in and out from the brain thus maintaining the CNS homeostasis. It is mainly composed of endothelial cells (ECs), pericytes and astrocytes that create a neurovascular unit (NVU) with the adjacent neurons. Astrocytes are essential for the formation and maintenance of the BBB by providing secreted factors that lead to the adequate association between the cells of the BBB and the formation of strong tight junctions. Under neurological disorders, such as chronic cerebral ischemia, brain trauma, Epilepsy, Alzheimer and Parkinson's Diseases, a disruption of the BBB takes place, involving a lost in the permeability of the barrier and phenotypical changes in both the ECs and astrocytes. In this aspect, it has been established that the process of reactive gliosis is a common feature of astrocytes during BBB disruption, which has a detrimental effect on the barrier function and a subsequent damage in neuronal survival. In this review we discuss the implications of astrocyte functions in the protection of the BBB, and in the development of Parkinson's disease (PD) and related disorders. Additionally, we highlight the current and future strategies in astrocyte protection aimed at the development of restorative therapies for the BBB in pathological conditions. PMID:25136294

  14. Efflux transporters at the blood-brain barrier limit delivery and efficacy of cyclin-dependent kinase 4/6 inhibitor palbociclib (PD-0332991) in an orthotopic brain tumor model.

    PubMed

    Parrish, Karen E; Pokorny, Jenny; Mittapalli, Rajendar K; Bakken, Katrina; Sarkaria, Jann N; Elmquist, William F

    2015-11-01

    6-Acetyl-8-cyclopentyl-5-methyl-2-([5-(piperazin-1-yl)pyridin-2-yl]amino)pyrido(2,3-d)pyrimidin-7(8H)-one [palbociclib (PD-0332991)] is a cyclin-dependent kinase 4/6 inhibitor approved for the treatment of metastatic breast cancer and is currently undergoing clinical trials for many solid tumors. Glioblastoma (GBM) is the most common primary brain tumor in adults and has limited treatment options. The cyclin-dependent kinase 4/6 pathway is commonly dysregulated in GBM and is a promising target in treating this devastating disease. The blood-brain barrier (BBB) limits the delivery of drugs to invasive regions of GBM, where the efflux transporters P-glycoprotein and breast cancer resistance protein can prevent treatments from reaching the tumor. The purpose of this study was to examine the mechanisms limiting the effectiveness of palbociclib therapy in an orthotopic xenograft model. The in vitro intracellular accumulation results demonstrated that palbociclib is a substrate for both P-glycoprotein and breast cancer resistance protein. In vivo studies in transgenic mice confirmed that efflux transport is responsible for the limited brain distribution of palbociclib. There was an ∼115-fold increase in brain exposure at steady state in the transporter deficient mice when compared with wild-type mice, and the efflux inhibitor elacridar significantly increased palbociclib brain distribution. Efficacy studies demonstrated that palbociclib is an effective therapy when GBM22 tumor cells are implanted in the flank, but ineffective in an orthotopic (intracranial) model. Moreover, doses designed to mimic brain exposure were ineffective in treating flank tumors. These results demonstrate that efflux transport in the BBB is involved in limiting the brain distribution of palbociclib and this has critical implications in determining effective dosing regimens of palbociclib therapy in the treatment of brain tumors. PMID:26354993

  15. The Blood Brain Barrier in Neurodegenerative Disease: A Rhetorical Perspective

    PubMed Central

    Carvey, Paul M; Hendey, Bill; Monahan, Angela J.

    2009-01-01

    Recent studies suggest that the function of the blood brain barrier (BBB) is not static under normal physiological conditions and is likely altered in neurodegenerative disease. Prevailing thinking about CNS function, and neurodegenerative disease in particular, is neurocentric excluding the impact of factors outside of the CNS. This review challenges this perspective and discusses recent reports suggesting the involvement of peripheral factors including toxins and elements of adaptive immunity that may not only play a role in pathogenesis, but also progression of neurodegenerative diseases. Central to this view is neuroinflammation. Several studies indicate that the neuroinflammatory changes that accompany neurodegeneration affect the BBB or its function by altering transport systems, enhancing immune cell entry, or influencing the BBB’s role as a signaling interface. Such changes impair the BBB’s normal homeostatic function and affect neural activity. Moreover, recent studies reveal that alterations in BBB and its transporters affect the entry of drugs used to treat neurodegenerative diseases. Incorporating BBB compromise and dysfunction into our view of neurodegenerative disease leads to inclusion of peripheral mediators in its pathogenesis and progression. In addition, this changing view of the BBB raises interesting new therapeutic possibilities for drug delivery as well as treatment strategies designed to reinstate normal barrier function. PMID:19659460

  16. Drug transport across the blood-brain barrier.

    PubMed

    Pardridge, William M

    2012-11-01

    The blood-brain barrier (BBB) prevents the brain uptake of most pharmaceuticals. This property arises from the epithelial-like tight junctions within the brain capillary endothelium. The BBB is anatomically and functionally distinct from the blood-cerebrospinal fluid barrier at the choroid plexus. Certain small molecule drugs may cross the BBB via lipid-mediated free diffusion, providing the drug has a molecular weight <400 Da and forms <8 hydrogen bonds. These chemical properties are lacking in the majority of small molecule drugs, and all large molecule drugs. Nevertheless, drugs can be reengineered for BBB transport, based on the knowledge of the endogenous transport systems within the BBB. Small molecule drugs can be synthesized that access carrier-mediated transport (CMT) systems within the BBB. Large molecule drugs can be reengineered with molecular Trojan horse delivery systems to access receptor-mediated transport (RMT) systems within the BBB. Peptide and antisense radiopharmaceuticals are made brain-penetrating with the combined use of RMT-based delivery systems and avidin-biotin technology. Knowledge on the endogenous CMT and RMT systems expressed at the BBB enable new solutions to the problem of BBB drug transport. PMID:22929442

  17. Studies on microwave and blood-brain barrier interaction

    SciTech Connect

    Lin, J.C.; Lin, M.F.

    1980-01-01

    This investigation was aimed at correlating changes of blood-brain-barrier permeability with the quantity and distribution of absorbed microwave energy inside the brain of adult Wistar rats anesthetized by sodium pentobarbital. Through use of thermographic methods and a direct-contact applicator at the animal's head, the pattern of absorbed microwave energy was determined. Indwelling catheters were placed in the femoral vein and in the left external carotid artery. Evans blue and sodium fluorescein in isotonic saline were used as visual indicators of barrier permeation. Exposure to pulsed 2,450-MHz radiation for 20 min at average power densities of 0.5, 1, 5, 20, 145 or 1,000 mW/cm2, which resulted in average specific absorption rates (SARs) of 0.04, 0.08, 0.4, 1.6, 11.5 or 80.0 mW/g in the brain, did not produce staining, except in the pineal body, the pituitary gland, and the choroid plexus - regions that normally are highly permeable. Except for these regions, staining was also absent in the brains of sham-exposed animals. The rectal temperature, as monitored by a copper-constantan thermocouple, showed a maximum increase of less than 0.75 degrees C from a mean pre-exposure temperature of 36.6 degrees C. The highest brain temperature recorded in a similar group of animals using a thickfilm carbon thermistor was less than 41.0 degrees C.

  18. Evolving Drug Delivery Strategies to Overcome the Blood Brain Barrier

    PubMed Central

    Hersh, David S.; Wadajkar, Aniket S.; Roberts, Nathan B.; Perez, Jimena G.; Connolly, Nina P.; Frenkel, Victor; Winkles, Jeffrey A.; Woodworth, Graeme F.; Kim, Anthony J.

    2016-01-01

    The blood-brain barrier (BBB) poses a unique challenge for drug delivery to the central nervous system (CNS). The BBB consists of a continuous layer of specialized endothelial cells linked together by tight junctions, pericytes, nonfenestrated basal lamina, and astrocytic foot processes. This complex barrier controls and limits the systemic delivery of therapeutics to the CNS. Several innovative strategies have been explored to enhance the transport of therapeutics across the BBB, each with individual advantages and disadvantages. Ongoing advances in delivery approaches that overcome the BBB are enabling more effective therapies for CNS diseases. In this review, we discuss: (1) the physiological properties of the BBB, (2) conventional strategies to enhance paracellular and transcellular transport through the BBB, (3) emerging concepts to overcome the BBB, and (4) alternative CNS drug delivery strategies that bypass the BBB entirely. Based on these exciting advances, we anticipate that in the near future, drug delivery research efforts will lead to more effective therapeutic interventions for diseases of the CNS.

  19. The Blood-Brain Barrier: Bottleneck in Brain Drug Development

    PubMed Central

    Pardridge, William M.

    2005-01-01

    Summary: The blood-brain barrier (BBB) is formed by the brain capillary endothelium and excludes from the brain ∼100% of large-molecule neurotherapeutics and more than 98% of all small-molecule drugs. Despite the importance of the BBB to the neurotherapeutics mission, the BBB receives insufficient attention in either academic neuroscience or industry programs. The combination of so little effort in developing solutions to the BBB problem, and the minimal BBB transport of the majority of all potential CNS drugs, leads predictably to the present situation in neurotherapeutics, which is that there are few effective treatments for the majority of CNS disorders. This situation can be reversed by an accelerated effort to develop a knowledge base in the fundamental transport properties of the BBB, and the molecular and cellular biology of the brain capillary endothelium. This provides the platform for CNS drug delivery programs, which should be developed in parallel with traditional CNS drug discovery efforts in the molecular neurosciences. PMID:15717053

  20. Estrogen and insulin transport through the blood-brain barrier.

    PubMed

    May, Aaron A; Bedel, Nicholas D; Shen, Ling; Woods, Stephen C; Liu, Min

    2016-09-01

    Obesity is associated with insulin resistance and reduced transport of insulin through the blood-brain barrier (BBB). Reversal of high-fat diet-induced obesity (HFD-DIO) by dietary intervention improves the transport of insulin through the BBB and the sensitivity of insulin in the brain. Although both insulin and estrogen (E2), when given alone, reduce food intake and body weight via the brain, E2 actually renders the brain relatively insensitive to insulin's catabolic action. The objective of these studies was to determine if E2 influences the ability of insulin to be transported into the brain, since the receptors for both E2 and insulin are found in BBB endothelial cells. E2 (acute or chronic) was systemically administered to ovariectomized (OVX) female rats and male rats fed a chow or a high-fat diet. Food intake, body weight and other metabolic parameters were assessed along with insulin entry into the cerebrospinal fluid (CSF). Acute E2 treatment in OVX female and male rats reduced body weight and food intake, and chronic E2 treatment prevented or partially reversed high-fat diet-induced obesity. However, none of these conditions increased insulin transport into the CNS; rather, chronic E2 treatment was associated less-effective insulin transport into the CNS relative to weight-matched controls. Thus, the reduction of brain insulin sensitivity by E2 is unlikely to be mediated by increasing the amount of insulin entering the CNS. PMID:27182046

  1. Cytokine Signaling Modulates Blood-Brain Barrier Function

    PubMed Central

    Pan, Weihong; Stone, Kirsten P.; Hsuchou, Hung; Manda, Vamshi K.; Zhang, Yan; Kastin, Abba J.

    2014-01-01

    The blood-brain barrier (BBB) provides a vast interface for cytokines to affect CNS function. The BBB is a target for therapeutic intervention. It is essential, therefore, to understand how cytokines interact with each other at the level of the BBB and how secondary signals modulate CNS functions beyond the BBB. The interactions between cytokines and lipids, however, have not been fully addressed at the level of the BBB. Here, we summarize current understanding of the localization of cytokine receptors and transporters in specific membrane microdomains, particularly lipid rafts, on the luminal (apical) surface of the microvascular endothelial cells composing the BBB. We then illustrate the clinical context of cytokine effects on the BBB by neuroendocrine regulation and amplification of inflammatory signals. Two unusual aspects discussed are signaling crosstalk by different classes of cytokines and genetic regulation of drug efflux transporters. We also introduce a novel area of focus on how cytokines may act through nuclear hormone receptors to modulate efflux transporters and other targets. A specific example discussed is the ATP-binding cassette transporter-1 (ABCA-1) that regulates lipid metabolism. Overall, cytokine signaling at the level of the BBB is a crucial feature of the dynamic regulation that can rapidly change BBB function and affect brain health and disease. PMID:21834767

  2. Blood-brain barrier disruption during spontaneous canine visceral leishmaniasis.

    PubMed

    Melo, G D; Grano, F G; Silva, J E S; Kremer, B E; Lima, V M F; Machado, G F

    2015-12-01

    Visceral leishmaniasis is a complex disease caused by Leishmania infantum, and in dogs, besides the classical symptoms, there are descriptions of inflammatory alterations in the brain. Brain inflammation is a strictly controlled process, and as the brain counts on the efficiency of the blood-brain barrier (BBB), we aimed to assess BBB integrity in dogs with spontaneous visceral leishmaniasis. Therefore, we evaluated markers in the cerebrospinal fluid (CSF) and in brain tissue related to BBB disruption and brain inflammation. Elevated albumin quota revealed BBB breakdown, corroborated by increased concentrations of anti-Leishmania antibodies in the CSF. In the brain, albumin and IgG staining formed halos around blood vessels, a classical indicator of BBB leakage. Soluble IgG was also detected in the choroid plexus and ependyma, and in these structures, IgG stained random resident cells. IgG(+) cells and Fcγ-RI(+) cells were identified in the choroid plexus, ependyma and perivascular in the brain parenchyma. The data support the occurrence of BBB disruption in dogs with spontaneous visceral leishmaniasis, and IgG as a key molecule that is capable of initiating and/or maintaining the inflammatory stimuli in the nervous milieu and the CSF as an important disseminator of inflammatory stimuli within the CNS. PMID:26434684

  3. Sleep restriction impairs blood-brain barrier function.

    PubMed

    He, Junyun; Hsuchou, Hung; He, Yi; Kastin, Abba J; Wang, Yuping; Pan, Weihong

    2014-10-29

    The blood-brain barrier (BBB) is a large regulatory and exchange interface between the brain and peripheral circulation. We propose that changes of the BBB contribute to many pathophysiological processes in the brain of subjects with chronic sleep restriction (CSR). To achieve CSR that mimics a common pattern of human sleep loss, we quantified a new procedure of sleep disruption in mice by a week of consecutive sleep recording. We then tested the hypothesis that CSR compromises microvascular function. CSR not only diminished endothelial and inducible nitric oxide synthase, endothelin1, and glucose transporter expression in cerebral microvessels of the BBB, but it also decreased 2-deoxy-glucose uptake by the brain. The expression of several tight junction proteins also was decreased, whereas the level of cyclooxygenase-2 increased. This coincided with an increase of paracellular permeability of the BBB to the small tracers sodium fluorescein and biotin. CSR for 6 d was sufficient to impair BBB structure and function, although the increase of paracellular permeability returned to baseline after 24 h of recovery sleep. This merits attention not only in neuroscience research but also in public health policy and clinical practice. PMID:25355222

  4. Stress does not increase blood-brain barrier permeability in mice.

    PubMed

    Roszkowski, Martin; Bohacek, Johannes

    2016-07-01

    Several studies have reported that exposure to acute psychophysiological stressors can lead to an increase in blood-brain barrier permeability, but these findings remain controversial and disputed. We thoroughly examined this issue by assessing the effect of several well-established paradigms of acute stress and chronic stress on blood-brain barrier permeability in several brain areas of adult mice. Using cerebral extraction ratio for the small molecule tracer sodium fluorescein (NaF, 376 Da) as a sensitive measure of blood-brain barrier permeability, we find that neither acute swim nor restraint stress lead to increased cerebral extraction ratio. Daily 6-h restraint stress for 21 days, a model for the severe detrimental impact of chronic stress on brain function, also does not alter cerebral extraction ratio. In contrast, we find that cold forced swim and cold restraint stress both lead to a transient, pronounced decrease of cerebral extraction ratio in hippocampus and cortex, suggesting that body temperature can be an important confounding factor in studies of blood-brain barrier permeability. To additionally assess if stress could change blood-brain barrier permeability for macromolecules, we measured cerebral extraction ratio for fluorescein isothiocyanate-dextran (70 kDa). We find that neither acute restraint nor cold swim stress affected blood-brain barrier permeability for macromolecules, thus corroborating our findings that various stressors do not increase blood-brain barrier permeability. PMID:27146513

  5. A correlative study of clinical-pathologic characteristics of human brain tumors and blood brain barrier (BBB) permeability evaluated with Ga-68 EDTA and positron emission tomography

    SciTech Connect

    Wapenski, J.A.; Hawkins, R.A.; Mazziotta, J.C.; Phelps, M.E.; Huang, S.C.

    1985-05-01

    The authors investigated the relationship between quantitative estimates of BBB permeability and the clinical and pathologic characteristics of human brain tumors. BBB permeability in 12 patients with either primary (4) or metastatic (8) brain tumors were studied with Ga-68 EDTA and PET with a two compartment model. The clinical and pathologic characteristics of the tumors were reviewed retrospectively. PET estimates of the transfer constant K/sub 1/ (ml/min/gm) paralleled the X-ray CT evidence of BBB disruption. Biopsies of four patients provided histologic support for the presumed pathophysiologic mechanism of BBB disruption, in the degree of alteration of brain vascularity and cellular architecture. For example, a patient with a hemorrhagic melanoma and a K/sub 1/ = 0.0049 ml/min/gm had gross hemorrhage, little recognizeable brain tissue and evidence of neovascularization on biopsy.

  6. Diabetes Mellitus and Blood-Brain Barrier Dysfunction: An Overview

    PubMed Central

    Prasad, Shikha; Sajja, Ravi K; Naik, Pooja; Cucullo, Luca

    2015-01-01

    A host of diabetes-related insults to the central nervous system (CNS) have been clearly documented in type-1 and -2 diabetic patients as well as experimental animal models. These host of neurological disorders encompass hemodynamic impairments (e.g., stroke), vascular dementia, cognitive deficits (mild to moderate), as well as a number of neurochemical, electrophysiological and behavioral alterations. The underlying causes of diabetes-induced CNS complications are multifactorial and are relatively little understood although it is now evident that blood-brain barrier (BBB) damage plays a significant role in diabetes-dependent CNS disorders. Changes in plasma glucose levels (hyper- or hypoglycemia) have been associated with altered BBB transport functions (e.g., glucose, insulin, choline, amino acids, etc.), integrity (tight junction disruption), and oxidative stress in the CNS microcapillaries. Last two implicating a potential causal role for upregulation and activation of the receptor for advanced glycation end products (RAGE). This type I membrane-protein also transports amyloid-beta (Aβ) from the blood into the brain across the BBB thus, establishing a link between type 2 diabetes mellitus (T2DM) and Alzheimer’s disease (AD, also referred to as “type 3 diabetes”). Hyperglycemia has been associated with progression of cerebral ischemia and the consequent enhancement of secondary brain injury. Difficulty in detecting vascular impairments in the large, heterogeneous brain microvascular bed and dissecting out the impact of hyper- and hypoglycemia in vivo has led to controversial results especially with regard to the effects of diabetes on BBB. In this article, we review the major findings and current knowledge with regard to the impact of diabetes on BBB integrity and function as well as specific brain microvascular effects of hyper- and hypoglycemia. PMID:25632404

  7. Hydrophilic solute transport across the rat blood-brain barrier

    SciTech Connect

    Lucchesi, K.J.

    1987-01-01

    Brain capillary permeability-surface area products (PS) of hydrophilic solutes ranging in size from 180 to 5,500 Daltons were measured in rats according to the method of Ohno, Pettigrew and Rapoport. The distribution volume of 70 KD dextran at 10 minutes after i.v. injection was also measured to determine the residual volume of blood in brain tissue at the time of sacrifice. Small test solutes were injected in pairs in order to elucidate whether their transfer into the brain proceeds by diffusion through water- or lipid-filled channels or by vesicular transport. This issue was examined in rats whose blood-brain barrier (BBB) was presumed to be intact (untreated) and in rats that received intracarotid infusions to open the BBB (isosmotic salt (ISS) and hyperosmolar arabinose). Ohno PS values of {sup 3}H-inulin and {sup 14}C-L-glucose in untreated rats were found to decrease as the labelling time was lengthened. This was evidence that a rapidly equilibrating compartment exists between blood and brain that renders the Ohno two-compartment model inadequate for computing true transfer rate constants. When the data were reanalyzed using a multi-compartment graphical analysis, solutes with different molecular radii were found to enter the brain at approximately equal rates. Furthermore, unidirectional transport is likely to be initiated by solute adsorption to a glycocalyx coat on the luminal surface of brain capillary endothelium. Apparently, more inulin than L-glucose was adsorbed, which may account for its slightly faster transfer across the BBB. After rats were treated with intracarotid infusions of ISS or hyperosmolar arabinose, solute PS values were significantly increased, but the ratio of PS for each of the solute pairs approached that of their free-diffusion coefficients.

  8. Methamphetamine effects on blood-brain barrier structure and function

    PubMed Central

    Northrop, Nicole A.; Yamamoto, Bryan K.

    2015-01-01

    Methamphetamine (Meth) is a widely abuse psychostimulant. Traditionally, studies have focused on the neurotoxic effects of Meth on monoaminergic neurotransmitter terminals. Recently, both in vitro and in vivo studies have investigated the effects of Meth on the BBB and found that Meth produces a decrease in BBB structural proteins and an increase in BBB permeability to various molecules. Moreover, preclinical studies are validated by clinical studies in which human Meth users have increased concentrations of toxins in the brain. Therefore, this review will focus on the structural and functional disruption of the BBB caused by Meth and the mechanisms that contribute to Meth-induced BBB disruption. The review will reveal that the mechanisms by which Meth damages dopamine and serotonin terminals are similar to the mechanisms by which the blood-brain barrier (BBB) is damaged. Furthermore, this review will cover the factors that are known to potentiate the effects of Meth (McCann et al., 1998) on the BBB, such as stress and HIV, both of which are co-morbid conditions associated with Meth abuse. Overall, the goal of this review is to demonstrate that the scope of damage produced by Meth goes beyond damage to monoaminergic neurotransmitter systems to include BBB disruption as well as provide a rationale for investigating therapeutics to treat Meth-induced BBB disruption. Since a breach of the BBB can have a multitude of consequences, therapies directed toward the treatment of BBB disruption may help to ameliorate the long-term neurodegeneration and cognitive deficits produced by Meth and possibly even Meth addiction. PMID:25788874

  9. Permeation of Dopamine Sulfate through the Blood-Brain Barrier

    PubMed Central

    Suominen, Tina; Piepponen, T. Petteri; Kostiainen, Risto

    2015-01-01

    Dopamine sulfate (DA-3- and DA-4-S) have been determined in the human brain, but it is unclear whether they are locally formed in the central nervous system (CNS), or transported into the CNS from peripheral sources. In the current study, permeation of the blood-brain barrier (BBB) by DA-S was studied by injecting 13C6-labelled regioisomers of DA-S (13DA-3-S and 13DA-4-S) and dopamine (DA) subcutaneously (s.c.) in anesthetized rats, then analyzing brain microdialysis and plasma samples by UPLC-MS/MS. The results in the microdialysis samples demonstrated that brain concentrations of 13DA-S regioisomers clearly increased after the s.c. injections. The concentration of DA did not change, indicating the permeation of DA-S through an intact BBB. The analysis of plasma samples, however, showed that DA-S only permeates the BBB to a small extent, as the concentrations in plasma were substantially higher than in the microdialysis samples. The results also showed that the concentrations of DA-3-S were around three times higher than the concentrations of DA-4-S in rat brain, as well as in the plasma samples after the s.c. injections, indicating that DA-3-S and DA-4-S permeate the BBB with similar efficiency. The fate of 13DA-S in brain was followed by monitoring 13C6-labelled DA-S hydrolysis products, i.e. 13DA and its common metabolites; however, no 13C6-labelled products were detected. This suggests that DA-S either permeates through the BBB back to the peripheral circulation or is dissociated or metabolized by unexpected mechanisms. PMID:26207745

  10. Noninvasive Blood-Brain Barrier Opening in Live Mice

    NASA Astrophysics Data System (ADS)

    Choi, James J.; Pernot, Mathieu; Small, Scott; Konofagou, Elisa E.

    2006-05-01

    Most therapeutic agents cannot be delivered to the brain because of brain's natural defense: the Blood-Brain Barrier (BBB). It has recently been shown that Focused Ultrasound (FUS) can produce reversible and localized BBB opening in the brain when applied in the presence of ultrasound contrast agents post-craniotomy in rabbits [1]. However, a major limitation of ultrasound in the brain is the strong phase aberration and attenuation of the skull bone, and, as a result, no study of trans-cranial ultrasound-targeted drug treatment in the brain in vivo has been reported as of yet. In this study, the feasibility of BBB opening in the hippocampus of wildtype mice using FUS through the intact skull and skin was investigated. In order to investigate the effect of the skull, simulations of ultrasound wave propagation (1.5 MHz) through the skull using μCT data, and needle hydrophone measurements through an ex-vivo skull were made. The pressure field showed minimal attenuation (18% of the pressure amplitude) and a well-focused pattern through the left and right halves of the parietal bone. In experiments in vivo, the brains of four mice were sonicated through intact skull and skin. Ultrasound sonications (burst length: 20 ms; duty cycle: 20%; acoustic pressure range: 2.0 to 2.7 MPa) was applied 5 times for 30 s per shot with a 30 s delay between shots. Prior to sonication, ultrasound contrast agents (Optison; 10 μL) were injected intravenously. Contrast material enhanced high resolution MR Imaging (9.4 Tesla) was able to distinguish opening of large vessels in the region of the hippocampus. These results demonstrate the feasibility of locally opening the BBB in the mouse hippocampus using focused ultrasound through intact skull and skin. Future investigations will deal with optimization and reproducibility of the technique as well as application on Alzheimer's-model mice.

  11. Blood-brain barrier damage in vascular dementia.

    PubMed

    Ueno, Masaki; Chiba, Yoichi; Matsumoto, Koichi; Murakami, Ryuta; Fujihara, Ryuji; Kawauchi, Machi; Miyanaka, Hiroshi; Nakagawa, Toshitaka

    2016-04-01

    New findings on flow or drainage pathways of brain interstitial fluid and cerebrospinal fluid have been made. The interstitial fluid flow has an effect on the passage of blood-borne substances in the brain parenchyma, especially in areas near blood-brain barrier (BBB)-free regions. Actually, blood-borne substances can be transferred in areas with intact BBB function, such as the hippocampus, the corpus callosum, periventricular areas, and medial portions of the amygdala, presumably through leaky vessels in the subfornical organs or the choroid plexus. Increasing evidence indicates that dysfunction of the BBB function may play a significant role in the pathogenesis of vascular dementia. Accordingly, we have examined which insults seen in patients suffering from vascular dementia have an effect on the BBB using experimental animal models exhibiting some phenotypes of vascular dementia. The BBB in the hippocampus was clearly deteriorated in Mongolian gerbils exposed to acute ischemia followed by reperfusion and also in stroke-prone spontaneously hypertensive rats (SHRSP) showing hypertension. The BBB in the corpus callosum was clearly deteriorated in Wistar rats with permanent ligation of the bilateral common carotid arteries showing chronic hypoperfusion. The BBB in the hippocampus and the olfactory bulb was mildly deteriorated in aged senescence accelerated prone mice (SAMP8) showing cognitive dysfunction. The BBB in the hippocampus was mildly deteriorated in aged animals with hydrocephalus. Mild endothelial damage was seen in hyperglycemic db/db mice. In addition, mRNA expression of osteopontin, matrix metalloproteinase-13 (MMP-13), and CD36 was increased in vessels showing BBB damage in hypertensive SHRSP. As osteopontin, MMP-13 and CD36 are known to be related to brain injury and amyloid β accumulation or clearance, BBB damage followed by increased gene expression of these molecules not only contributes to the pathogenesis of vascular dementia, but also bridges

  12. Rapid high-affinity transport of a chemotherapeutic amino acid across the blood-brain barrier.

    PubMed

    Takada, Y; Vistica, D T; Greig, N H; Purdon, D; Rapoport, S I; Smith, Q R

    1992-04-15

    The therapeutic efficacy of many anticancer drugs against intracerebral tumors is limited by poor uptake into the central nervous system. One way to enhance brain delivery is to design agents that are transported into the brain by the saturable nutrient carriers of the blood-brain barrier. In this paper, we describe a nitrogen mustard amino acid, DL-2-amino-7-bis[(2-chloroethyl)amino/bd-1,2,3,4-tetrahydro-2-napthoi c acid, that is taken up into brain with high affinity by the large neutral amino acid carrier of the blood-brain barrier. Brain transport of DL-2-amino-7-bis[(2-chloroethyl)aminol-1,2,3,4-tetrahydro-2-naphth oic acid in the rat was found to be rapid (cerebrovascular permeability-surface area product approximately 2 x 10(-2) ml/s/g), saturable and inhibitable by large neutral amino acids. Maximal influx rate (Vmax) and half-saturation (Km) constants equaled 0.26 nmol/min/g and 0.19 microM, respectively, in the parietal cortex. Regional brain uptake of acid exceeded that of the clinical analogue, melphalan, by greater than 20-fold. The results demonstrate that drug modification to produce high-affinity ligands for the cerebrovascular nutrient carriers is a viable means to enhance drug delivery to brain for the treatment of brain tumors and other central nervous system disorders. PMID:1559223

  13. Tumor location, but not H3.3K27M, significantly influences the blood-brain-barrier permeability in a genetic mouse model of pediatric high-grade glioma.

    PubMed

    Subashi, Ergys; Cordero, Francisco J; Halvorson, Kyle G; Qi, Yi; Nouls, John C; Becher, Oren J; Johnson, G Allan

    2016-01-01

    Pediatric high-grade gliomas (pHGGs) occur with strikingly different frequencies in infratentorial and supratentorial regions. Although histologically these malignancies appear similar, they represent distinct diseases. Recent genomic studies have identified histone K27M H3.3/H3.1 mutations in the majority of brainstem pHGGs; these mutations are rarely encountered in pHGGs that arise in the cerebral cortex. Previous research in brainstem pHGGs suggests a restricted permeability of the blood-brain-barrier (BBB). In this work, we use dynamic contrast-enhanced (DCE) MRI to evaluate BBB permeability in a genetic mouse model of pHGG as a function of location (cortex vs. brainstem, n = 8 mice/group) and histone mutation (mutant H3.3K27M vs. wild-type H3.3, n = 8 mice/group). The pHGG models are induced either in the brainstem or the cerebral cortex and are driven by PDGF signaling and p53 loss with either H3.3K27M or wild-type H3.3. T2-weighted MRI was used to determine tumor location/extent followed by 4D DCE-MRI for estimating the rate constant (K (trans) ) for tracer exchange across the barrier. BBB permeability was 67 % higher in cortical pHGGs relative to brainstem pHGGs (t test, p = 0.012) but was not significantly affected by the expression of mutant H3.3K27M versus wild-type H3.3 (t-test, p = 0.78). Although mice became symptomatic at approximately the same time, the mean volume of cortical tumors was 3.6 times higher than the mean volume of brainstem tumors. The difference between the mean volume of gliomas with wild-type and mutant H3.3 was insignificant. Mean K (trans) was significantly correlated to glioma volume. These results present a possible explanation for the poor response of brainstem pHGGs to systemic therapy. Our findings illustrate a potential role played by the microenvironment in shaping tumor growth and BBB permeability. PMID:26511492

  14. A study of the FDG model in the presence of an altered blood brain barrier (BBB) and glucose metabolic/flow relationships in human brain tumors with PET

    SciTech Connect

    Hawkins, R.A.; Phelps, M.E.; Huang, S.C.; Wapenski, J.A.; Silberman, A.W.

    1985-05-01

    The authors performed 3 hour kinetic FDG studies (5 parameter model, 5th parameter represents cerebral blood volume (CBV) on 8 patients with primary or metastatic brain tumors. One subject also had a direct measurement of BBB permeability with Ga-68 EDTA and 5 subjects also had cerebral blood flow (CBF) determinations with bolus injections of 0-15 water. Estimates of hexose distribution volumes (HDV=k/sub 1/*/k/sub 2/*), FDG distribution volumes (DV=k/sub 1/*/(k/sub 2/*+k/sub 3/*), a ratio R=k/sub 3/*k/sub 2/* that is related to the stability of the lumped constant (LC) and glucose extraction ratios (GER) were calculated. GER averaged 8.8 (+- 4.6)% in tumors, 7.7 (+- 1.7)% in gray matter, 10.3 (+- 3.8)% in white matter and 8.4 (+- 2.1)% in hemispheric regions. R averaged 0.46 (+- 0.19) in tumors, 0.47 (+- 0.24) in gray matter, 0.45 (+- 0.18) in white matter and 0.57 (+- 0.25) in hemispheric regions. HDV estimates were 0.33 (+- 0.11) in tumors, 0.48 (+- 0.25) in gray matter, 0.34 (+- 0.14) in white matter and 0.38 (+- 0.25) in hemispheric regions. DV estimates were smaller than HDV but were not significantly different over the same groups. These results suggest that the compartmental configuration of the FDG model is still appropriate in this set of patients with increased BBB permeability and that LC is relatively stable. A lack of significant increase in the FDG rate constants k/sub 1/* and k/sub 2/* with increases BBB permeability suggests that facilitated diffusion remains the dominant mechanism of glucose transport even with BBB abnormalities.

  15. Immortalized endothelial cell lines for in vitro blood-brain barrier models: A systematic review.

    PubMed

    Rahman, Nurul Adhwa; Rasil, Alifah Nur'ain Haji Mat; Meyding-Lamade, Uta; Craemer, Eva Maria; Diah, Suwarni; Tuah, Ani Afiqah; Muharram, Siti Hanna

    2016-07-01

    Endothelial cells play the most important role in construction of the blood-brain barrier. Many studies have opted to use commercially available, easily transfected or immortalized endothelial cell lines as in vitro blood-brain barrier models. Numerous endothelial cell lines are available, but we do not currently have strong evidence for which cell lines are optimal for establishment of such models. This review aimed to investigate the application of immortalized endothelial cell lines as in vitro blood-brain barrier models. The databases used for this review were PubMed, OVID MEDLINE, ProQuest, ScienceDirect, and SpringerLink. A narrative systematic review was conducted and identified 155 studies. As a result, 36 immortalized endothelial cell lines of human, mouse, rat, porcine and bovine origins were found for the establishment of in vitro blood-brain barrier and brain endothelium models. This review provides a summary of immortalized endothelial cell lines as a guideline for future studies and improvements in the establishment of in vitro blood-brain barrier models. It is important to establish a good and reproducible model that has the potential for multiple applications, in particular a model of such a complex compartment such as the blood-brain barrier. PMID:27086967

  16. Pharmacologic manipulation of lysosomal enzyme transport across the blood-brain barrier.

    PubMed

    Urayama, Akihiko; Grubb, Jeffrey H; Sly, William S; Banks, William A

    2016-03-01

    The adult blood-brain barrier, unlike the neonatal blood-brain barrier, does not transport lysosomal enzymes into brain, making enzyme replacement therapy ineffective in treating the central nervous system symptoms of lysosomal storage diseases. However, enzyme transport can be re-induced with alpha-adrenergics. Here, we examined agents that are known to alter the blood-brain barrier transport of large molecules or to induce lysosomal enzyme transport across the blood-brain barrier ((±)epinephrine, insulin, retinoic acid, and lipopolysaccharide) in 2-week-old and adult mice. In 2-week-old adolescent mice, all these pharmacologic agents increased brain and heart uptake of phosphorylated human β-glucuronidase. In 8-week-old adult mice, manipulations with (±)epinephrine, insulin, and retinoic acid were significantly effective on uptake by brain and heart. The increased uptake of phosphorylated human  β-glucuronidase was inhibited by mannose 6-phosphate for the agents (±)epinephrine and retinoic acid and by L-NG-nitroarginine methyl ester for the agent lipopolysaccharide in neonatal and adult mice. An in situ brain perfusion study revealed that retinoic acid directly modulated the transport of phosphorylated human β-glucuronidase across the blood-brain barrier. The present study indicates that there are multiple opportunities to at least transiently induce phosphorylated human β-glucuronidase transport at the adult blood-brain barrier. PMID:26661222

  17. What role does the blood brain barrier play in acute mountain sickness?

    PubMed

    Baneke, Alex

    2010-07-01

    As high altitude travel increases, acute mountain sickness (AMS) and life threatening high altitude cerebral oedema (HACE) are becoming more prevalent. Acute mountain sickness occurs in 45% of lowlanders above 4250 m. Predisposing factors are still unknown and its development is more complex than the original "tight fit" hypothesis. This review examines evidence relating to a possible role of the blood brain barrier in AMS as suggested by MRI studies. Underlying mechanisms may involve vascular endothelial growth factor and free radicals in addition to increases in hydrostatic pressure. An increased understanding is important in advising patients planning high altitude adventures. Current studies have linked increased blood brain barrier permeability to high altitude cerebral oedema, but the role of the blood brain barrier in acute mountain sickness is less clear; varied symptoms include headache. MRI shows vasogenic oedema occurs in high altitude cerebral oedema, suggesting blood brain barrier permeability increases, and acute mountain sickness typically precedes high altitude cerebral oedema. Hypoxia leads to increased hydrostatic pressure, and blood brain barrier permeability has been shown to increase in stroke patients. Vascular endothelial growth factor is upregulated in hypoxia, and may increase blood brain barrier permeability. PMID:20952272

  18. Comparison study of ferrofluid and powder iron oxide nanoparticle permeability across the blood-brain barrier.

    PubMed

    Hoff, Dan; Sheikh, Lubna; Bhattacharya, Soumya; Nayar, Suprabha; Webster, Thomas J

    2013-01-01

    In the present study, the permeability of 11 different iron oxide nanoparticle (IONP) samples (eight fluids and three powders) was determined using an in vitro blood-brain barrier model. Importantly, the results showed that the ferrofluid formulations were statistically more permeable than the IONP powder formulations at the blood-brain barrier, suggesting a role for the presently studied in situ synthesized ferrofluid formulations using poly(vinyl) alcohol, bovine serum albumin, collagen, glutamic acid, graphene, and their combinations as materials which can cross the blood-brain barrier to deliver drugs or have other neurological therapeutic efficacy. Conversely, the results showed the least permeability across the blood-brain barrier for the IONP with collagen formulation, suggesting a role as a magnetic resonance imaging contrast agent but limiting IONP passage across the blood-brain barrier. Further analysis of the data yielded several trends of note, with little correlation between permeability and fluid zeta potential, but a larger correlation between permeability and fluid particle size (with the smaller particle sizes having larger permeability). Such results lay the foundation for simple modification of iron oxide nanoparticle formulations to either promote or inhibit passage across the blood-brain barrier, and deserve further investigation for a wide range of applications. PMID:23426527

  19. Mechanisms of methylmercury transport across the blood-brain barrier

    SciTech Connect

    Kerper, L.E.

    1993-01-01

    Methylmercury readily enters the brain of exposed individuals, and is highly neurotoxic. The goal of this research was to determine the mechanisms of methylmercury transport across both the luminal and abluminal membranes of brain capillary endothelial cells, the cells which comprise the blood-brain barrier. The rapid carotid injection technique was used in rats to investigate the uptake of methylmercury from blood into brain endothelial cells. Uptake of ([sup 203]Hg)-methylmercury complexed with L-cysteine (CH[sub 3] [sup 203]Hg-L-Cys) was more rapid than that of ([sup 203]Hg)-methylmercury complexed with D-cysteine or bovine serum albumin. Uptake of CH[sub 3][sup 203]Hg-L-Cys was saturable, and was inhibited by substrates for the L (alanine-preferring) carrier. Brain uptake of [sup 14]C-L-methionine was inhibited by CH[sub 3]Hg-L-Cys but not by CH[sub 3]HgCl. Uptake of [sup 203]Hg administered as CH[sub 3]Hg-L-Cys-glutathione (CH[sub 3][sup 203]Hg-GSH) was comparable to CH[sub 3][sup 203]Hg-L-Cys uptake at 2 [mu]M. L-Methionine and 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH) inhibited [sup 203]Hg uptake administered as CH[sub 3][sup 203]Hg-GSH, whereas acivicin had no effect. This uptake was also inhibited by S-ethylglutathione when pH of the injection solution was allowed to rise to 8.5. In later experiments performed at pH 8.2, uptake of [sup 203]Hg administered as CH[sub 3][sup 203]Hg-GSH was inhibited only by BCH. To study mechanisms of methylmercury efflux from endothelial cells, a primary culture of bovine brain capillary endothelial cells was developed. Intracellular glutathione concentration was 2.6 [+-] 0.7 mM. Incubation of CH[sub 3][sup 203]HgCl-preloaded cells with GSH depletors decreased ([sup 203]Hg)-methylmercury efflux in a dose-dependent manner which correlated with intracellular GSH concentrations. ([sup 203]Hg)-Methylmercury efflux was also inhibited by GSH-S-conjugates an GSH analogs, but not by amino acids.

  20. Osmotic opening of the blood-brain barrier: principles, mechanism, and therapeutic applications.

    PubMed

    Rapoport, S I

    2000-04-01

    1. Osmotic opening of the blood-brain barrier by intracarotid infusion of a hypertonic arabinose or mannitol solution is mediated by vasodilatation and shrinkage of cerebrovascular endothelial cells, with widening of the interendothelial tight junctions to an estimated radius of 200 A. The effect may be facilitated by calcium-mediated contraction of the endothelial cytoskeleton. 2. The marked increase in apparent blood-brain barrier permeability to intravascular substances (10-fold for small molecules) following the osmotic procedure is due to both increased diffusion and bulk fluid flow across the tight junctions. The permeability effect is largely reversed within 10 min. 3. In experimental animals, the osmotic method has been used to grant wide access to the brain of water-soluble drugs, peptides, antibodies, boron compounds for neutron capture therapy, and viral vectors for gene therapy. The method also has been used together with anticancer drugs to treat patients with metastatic or primary brain tumors, with some success and minimal morbidity. PMID:10696511

  1. Astrocytic TYMP and VEGFA drive blood-brain barrier opening in inflammatory central nervous system lesions.

    PubMed

    Chapouly, Candice; Tadesse Argaw, Azeb; Horng, Sam; Castro, Kamilah; Zhang, Jingya; Asp, Linnea; Loo, Hannah; Laitman, Benjamin M; Mariani, John N; Straus Farber, Rebecca; Zaslavsky, Elena; Nudelman, German; Raine, Cedric S; John, Gareth R

    2015-06-01

    In inflammatory central nervous system conditions such as multiple sclerosis, breakdown of the blood-brain barrier is a key event in lesion pathogenesis, predisposing to oedema, excitotoxicity, and ingress of plasma proteins and inflammatory cells. Recently, we showed that reactive astrocytes drive blood-brain barrier opening, via production of vascular endothelial growth factor A (VEGFA). Here, we now identify thymidine phosphorylase (TYMP; previously known as endothelial cell growth factor 1, ECGF1) as a second key astrocyte-derived permeability factor, which interacts with VEGFA to induce blood-brain barrier disruption. The two are co-induced NFκB1-dependently in human astrocytes by the cytokine interleukin 1 beta (IL1B), and inactivation of Vegfa in vivo potentiates TYMP induction. In human central nervous system microvascular endothelial cells, VEGFA and the TYMP product 2-deoxy-d-ribose cooperatively repress tight junction proteins, driving permeability. Notably, this response represents part of a wider pattern of endothelial plasticity: 2-deoxy-d-ribose and VEGFA produce transcriptional programs encompassing angiogenic and permeability genes, and together regulate a third unique cohort. Functionally, each promotes proliferation and viability, and they cooperatively drive motility and angiogenesis. Importantly, introduction of either into mouse cortex promotes blood-brain barrier breakdown, and together they induce severe barrier disruption. In the multiple sclerosis model experimental autoimmune encephalitis, TYMP and VEGFA co-localize to reactive astrocytes, and correlate with blood-brain barrier permeability. Critically, blockade of either reduces neurologic deficit, blood-brain barrier disruption and pathology, and inhibiting both in combination enhances tissue preservation. Suggesting importance in human disease, TYMP and VEGFA both localize to reactive astrocytes in multiple sclerosis lesion samples. Collectively, these data identify TYMP as an

  2. The Drosophila blood-brain barrier: development and function of a glial endothelium.

    PubMed

    Limmer, Stefanie; Weiler, Astrid; Volkenhoff, Anne; Babatz, Felix; Klämbt, Christian

    2014-01-01

    The efficacy of neuronal function requires a well-balanced extracellular ion homeostasis and a steady supply with nutrients and metabolites. Therefore, all organisms equipped with a complex nervous system developed a so-called blood-brain barrier, protecting it from an uncontrolled entry of solutes, metabolites or pathogens. In higher vertebrates, this diffusion barrier is established by polarized endothelial cells that form extensive tight junctions, whereas in lower vertebrates and invertebrates the blood-brain barrier is exclusively formed by glial cells. Here, we review the development and function of the glial blood-brain barrier of Drosophila melanogaster. In the Drosophila nervous system, at least seven morphologically distinct glial cell classes can be distinguished. Two of these glial classes form the blood-brain barrier. Perineurial glial cells participate in nutrient uptake and establish a first diffusion barrier. The subperineurial glial (SPG) cells form septate junctions, which block paracellular diffusion and thus seal the nervous system from the hemolymph. We summarize the molecular basis of septate junction formation and address the different transport systems expressed by the blood-brain barrier forming glial cells. PMID:25452710

  3. The Drosophila blood-brain barrier: development and function of a glial endothelium

    PubMed Central

    Limmer, Stefanie; Weiler, Astrid; Volkenhoff, Anne; Babatz, Felix; Klämbt, Christian

    2014-01-01

    The efficacy of neuronal function requires a well-balanced extracellular ion homeostasis and a steady supply with nutrients and metabolites. Therefore, all organisms equipped with a complex nervous system developed a so-called blood-brain barrier, protecting it from an uncontrolled entry of solutes, metabolites or pathogens. In higher vertebrates, this diffusion barrier is established by polarized endothelial cells that form extensive tight junctions, whereas in lower vertebrates and invertebrates the blood-brain barrier is exclusively formed by glial cells. Here, we review the development and function of the glial blood-brain barrier of Drosophila melanogaster. In the Drosophila nervous system, at least seven morphologically distinct glial cell classes can be distinguished. Two of these glial classes form the blood-brain barrier. Perineurial glial cells participate in nutrient uptake and establish a first diffusion barrier. The subperineurial glial (SPG) cells form septate junctions, which block paracellular diffusion and thus seal the nervous system from the hemolymph. We summarize the molecular basis of septate junction formation and address the different transport systems expressed by the blood-brain barrier forming glial cells. PMID:25452710

  4. Anti–IL-6 neutralizing antibody modulates blood-brain barrier function in the ovine fetus

    PubMed Central

    Zhang, Jiyong; Sadowska, Grazyna B.; Chen, Xiaodi; Park, Seon Yeong; Kim, Jeong-Eun; Bodge, Courtney A.; Cummings, Erin; Lim, Yow-Pin; Makeyev, Oleksandr; Besio, Walter G.; Gaitanis, John; Banks, William A.; Stonestreet, Barbara S.

    2015-01-01

    Impaired blood-brain barrier function represents an important component of hypoxic-ischemic brain injury in the perinatal period. Proinflammatory cytokines could contribute to ischemia-related blood-brain barrier dysfunction. IL-6 increases vascular endothelial cell monolayer permeability in vitro. However, contributions of IL-6 to blood-brain barrier abnormalities have not been examined in the immature brain in vivo. We generated pharmacologic quantities of ovine-specific neutralizing anti-IL-6 mAbs and systemically infused mAbs into fetal sheep at 126 days of gestation after exposure to brain ischemia. Anti–IL-6 mAbs were measured by ELISA in fetal plasma, cerebral cortex, and cerebrospinal fluid, blood-brain barrier permeability was quantified using the blood-to-brain transfer constant in brain regions, and IL-6, tight junction proteins, and plasmalemma vesicle protein (PLVAP) were detected by Western immunoblot. Anti–IL-6 mAb infusions resulted in increases in mAb (P < 0.05) in plasma, brain parenchyma, and cerebrospinal fluid and decreases in brain IL-6 protein. Twenty-four hours after ischemia, anti–IL-6 mAb infusions attenuated ischemia-related increases in blood-brain barrier permeability and modulated tight junction and PLVAP protein expression in fetal brain. We conclude that inhibiting the effects of IL-6 protein with systemic infusions of neutralizing antibodies attenuates ischemia-related increases in blood-brain barrier permeability by inhibiting IL-6 and modulates tight junction proteins after ischemia.—Zhang, J., Sadowska, G. B., Chen, X., Park, S. Y., Kim, J.-E., Bodge, C. A., Cummings, E., Lim, Y.-P., Makeyev, O., Besio, W. G., Gaitanis, J., Banks, W. A., Stonestreet, B. S. Anti–IL-6 neutralizing antibody modulates blood-brain barrier function in the ovine fetus. PMID:25609424

  5. Drug interactions at the blood-brain barrier: fact or fantasy?

    PubMed Central

    Eyal, Sara; Hsiao, Peng; Unadkat, Jashvant D.

    2009-01-01

    There is considerable interest in the therapeutic and adverse outcomes of drug interactions at the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB). These include altered efficacy of drugs used in the treatment of CNS disorders, such as AIDS dementia and malignant tumors, and enhanced neurotoxicity of drugs that normally penetrate poorly into the brain. BBB- and BCSFB-mediated interactions are possible because these interfaces are not only passive anatomical barriers, but are also dynamic in that they express a variety of influx and efflux transporters and drug metabolizing enzymes. Based on studies in rodents, it has been widely postulated that efflux transporters play an important role at the human BBB in terms of drug delivery. Furthermore, it is assumed that chemical inhibition of transporters or their genetic ablation in rodents is predictive of the magnitude of interaction to be expected at the human BBB. However, studies in humans challenge this well-established paradigm and claim that such drug interactions will be lesser in magnitude but yet may be clinically significant. This review focuses on current known mechanisms of drug interactions at the blood-brain and blood-CSF barriers and the potential impact of such interactions in humans. We also explore whether such drug interactions can be predicted from preclinical studies. Defining the mechanisms and the impact of drug-drug interactions at the BBB is important for improving efficacy of drugs used in the treatment of CNS disorders while minimizing their toxicity as well as minimizing neurotoxicity of non-CNS drugs. PMID:19393264

  6. Therapeutic strategies to improve drug delivery across the blood-brain barrier

    PubMed Central

    Azad, Tej D.; Pan, James; Connolly, Ian D.; Remington, Austin; Wilson, Christy M.; Grant, Gerald A.

    2015-01-01

    Resection of brain tumors is followed by chemotherapy and radiation to ablate remaining malignant cell populations. Targeting these populations stands to reduce tumor recurrence and offer the promise of more complete therapy. Thus, improving access to the tumor, while leaving normal brain tissue unscathed, is a critical pursuit. A central challenge in this endeavor lies in the limited delivery of therapeutics to the tumor itself. The blood-brain barrier (BBB) is responsible for much of this difficulty but also provides an essential separation from systemic circulation. Due to the BBB’s physical and chemical constraints, many current therapies, from cytotoxic drugs to antibody-based proteins, cannot gain access to the tumor. This review describes the characteristics of the BBB and associated changes wrought by the presence of a tumor. Current strategies for enhancing the delivery of therapies across the BBB to the tumor will be discussed, with a distinction made between strategies that seek to disrupt the BBB and those that aim to circumvent it. PMID:25727231

  7. Blood-brain barrier and brain fatty acid uptake: Role of arachidonic acid and PGE2.

    PubMed

    Murphy, Eric J

    2015-12-01

    How do fatty acids enter the brain and what role, if any, do membrane and cytosolic fatty acid binding proteins have on facilitating this process? This is a fundamental question that many lipid neurochemists will freely admit they cannot answer in any kind of definitive manner. A study by Dalvi and colleagues in this issue of the Journal of Neurochemistry now adds to our knowledge in this field. Among other important observations, their experiments demonstrate that a physiological level of arachidonic acid (ARA), that could be associated with many different physiological and pathophysiological states, increases permeability in a model of the human blood brain barrier (BBB) in the absence of cytokines. This last point is very important as it suggests increases in BBB permeability may occur in situations other than those associated with increases in tumor necrosis factor a (TNFα) and interleukin1b (IL1β), giving additional options for developing drugs impacting BBB permeability. PMID:26383055

  8. The protective influence of the locus ceruleus on the blood-brain barrier

    SciTech Connect

    Harik, S.I.; McGunigal, T. Jr.

    1984-06-01

    The functions of the putative noradrenergic innervation of cerebral microvessels from the nucleus locus ceruleus remain ambiguous. Although most evidence indicates that such innervation does not have a major role in the control of cerebral blood flow, there are increasing indications that it modulates transport and permeability functions of the blood-brain barrier. In this study we investigated the effect of unilateral chemical lesioning of the locus ceruleus on the leakage of radioiodinated human serum albumin across the blood-brain barrier. Experiments were performed in awake and restrained rats under steady-state conditions and during drug-induced systemic arterial hypertension, and in anesthetized and paralyzed rats during bicuculline-induced seizures. Both hypertension and seizures are known to be associated with increased leakage of macromolecules across the blood-brain barrier. Albumin leakage into norepinephrine-depleted forebrain structures ipsilateral to the locus ceruleus lesion was compared with that of the contralateral side. There were no side-to-side differences in blood-brain barrier permeability to albumin under steady-state conditions, the stress of restraint, or angiotensin-induced hypertension, or after isoproterenol administration. Norepinephrine-induced hypertension and seizures, however, caused significant increases in albumin leakage into forebrain structures ipsilateral to the lesion. These results suggest that noradrenergic innervation of cerebral microvessels from the locus ceruleus helps preserve the integrity of the blood-brain barrier during pathophysiological states associated with hypertension and increased circulating catecholamines.

  9. Blood-Brain Barrier Penetration and in Vivo Activity of an NGF Conjugate

    NASA Astrophysics Data System (ADS)

    Friden, Phillip M.; Walus, Lee R.; Watson, Patricia; Doctrow, Susan R.; Kozarich, John W.; Backman, Cristina; Bergman, Hanna; Hoffer, Barry; Bloom, Floyd; Granholm, Ann-Charlotte

    1993-01-01

    Nerve growth factor (NGF) is essential for the survival of both peripheral ganglion cells and central cholinergic neurons of the basal forebrain. The accelerated loss of central cholinergic neurons during Alzheimer's disease may be a determinant of dementia in these patients and may therefore suggest a therapeutic role for NGF. However, NGF does not significantly penetrate the blood-brain barrier, which makes its clinical utility dependent on invasive neurosurgical procedures. When conjugated to an antibody to the transferrin receptor, however, NGF crossed the blood-brain barrier after peripheral injection. This conjugated NGF increased the survival of both cholinergic and noncholinergic neurons of the medial septal nucleus that had been transplanted into the anterior chamber of the rat eye. This approach may prove useful for the treatment of Alzheimer's disease and other neurological disorders that are amenable to treatment by proteins that do not readily cross the blood-brain barrier.

  10. MR assessment of radiation-induced blood-brain barrier permeability changes in a rat glioma model

    SciTech Connect

    Krueck, W.G. Univ. of Washington School of Medicine, Seattle, WA ); Schmiedl, U.P.; Maravilla, K.R.; Starr, F.L.; Kenney, J. )

    1994-04-01

    To assess the potential of a T1-weighted, gadolinium-enhanced MR technique for quantifying radiation-induced changes of blood-brain barrier permeability in a model of stereotactically implanted intracerebral gliomas in rats. We calculated the gadolinium blood-to-tissue transport coefficient for gadopentetate dimeglumine from signal intensities in sequential MR images in nine control animals that were not irradiated and in five and three animals that had received 2500 cGy and 1500 cGy whole-brain irradiation, respectively, at 2 days before imaging. The average blood-to-tissue transport coefficient values were 9.76 mL[center dot]kg[sup [minus]1][center dot]min[sup [minus]1] in the control group, 23.41 mL[center dot]kg[sup [minus]1][center dot]min[sup [minus]1] in the 2500-cGy group, and 25.63 mL[center dot]kg[sup [minus]1][center dot]min[sup [minus]1] in the 1500-cGy group. Blood-to-tissue transport coefficients were significantly higher after irradiation, indicating increased radiation-induced blood-brain barrier permeability. Similar increased blood-brain barrier leakiness in brain tumors after high-dose irradiation has been shown by previous nuclear medicine studies using quantitative autoradiography. Contrast-enhanced dynamic MR of brain gliomas is a sensitive method to document radiation-induced blood-brain barrier breakdown. Quantitative gadolinium-enhanced MR may become a useful tool for the management of patients with brain tumors undergoing radiation therapy. 28 refs., 4 figs., 1 tab.

  11. Pharmacokinetics and In Vitro Blood-Brain Barrier Screening of the Plant-Derived Alkaloid Tryptanthrin.

    PubMed

    Jähne, Evelyn A; Eigenmann, Daniela E; Sampath, Chethan; Butterweck, Veronika; Culot, Maxime; Cecchelli, Roméo; Gosselet, Fabien; Walter, Fruzsina R; Deli, Mária A; Smieško, Martin; Hamburger, Matthias; Oufir, Mouhssin

    2016-07-01

    The indolo[2,1-b]quinazoline alkaloid tryptanthrin was previously identified as a potent anti-inflammatory compound with a unique pharmacological profile. It is a potent inhibitor of cyclooxygenase-2, 5-lipooxygenase-catalyzed leukotriene synthesis, and nitric oxide production catalyzed by the inducible nitric oxide synthase. To characterize the pharmacokinetic properties of tryptanthrin, we performed a pilot in vivo study in male Sprague-Dawley rats (2 mg/kg bw i. v.). Moreover, the ability of tryptanthrin to cross the blood-brain barrier was evaluated in three in vitro human and animal blood-brain barrier models. Bioanalytical UPLC-MS/MS methods used were validated according to current international guidelines. A half-life of 40.63 ± 6.66 min and a clearance of 1.00 ± 0.36 L/h/kg were found in the in vivo pharmacokinetic study. In vitro data obtained with the two primary animal blood-brain barrier models showed a good correlation with an immortalized human monoculture blood-brain barrier model (hBMEC cell line), and were indicative of a high blood-brain barrier permeation potential of tryptanthrin. These findings were corroborated by the in silico prediction of blood-brain barrier penetration. P-glycoprotein interaction of tryptanthrin was assessed by calculation of the efflux ratio in bidirectional permeability assays. An efflux ratio below 2 indicated that tryptanthrin is not subjected to active efflux. PMID:27093249

  12. Anti-IL-6 neutralizing antibody modulates blood-brain barrier function in the ovine fetus.

    PubMed

    Zhang, Jiyong; Sadowska, Grazyna B; Chen, Xiaodi; Park, Seon Yeong; Kim, Jeong-Eun; Bodge, Courtney A; Cummings, Erin; Lim, Yow-Pin; Makeyev, Oleksandr; Besio, Walter G; Gaitanis, John; Banks, William A; Stonestreet, Barbara S

    2015-05-01

    Impaired blood-brain barrier function represents an important component of hypoxic-ischemic brain injury in the perinatal period. Proinflammatory cytokines could contribute to ischemia-related blood-brain barrier dysfunction. IL-6 increases vascular endothelial cell monolayer permeability in vitro. However, contributions of IL-6 to blood-brain barrier abnormalities have not been examined in the immature brain in vivo. We generated pharmacologic quantities of ovine-specific neutralizing anti-IL-6 mAbs and systemically infused mAbs into fetal sheep at 126 days of gestation after exposure to brain ischemia. Anti-IL-6 mAbs were measured by ELISA in fetal plasma, cerebral cortex, and cerebrospinal fluid, blood-brain barrier permeability was quantified using the blood-to-brain transfer constant in brain regions, and IL-6, tight junction proteins, and plasmalemma vesicle protein (PLVAP) were detected by Western immunoblot. Anti-IL-6 mAb infusions resulted in increases in mAb (P < 0.05) in plasma, brain parenchyma, and cerebrospinal fluid and decreases in brain IL-6 protein. Twenty-four hours after ischemia, anti-IL-6 mAb infusions attenuated ischemia-related increases in blood-brain barrier permeability and modulated tight junction and PLVAP protein expression in fetal brain. We conclude that inhibiting the effects of IL-6 protein with systemic infusions of neutralizing antibodies attenuates ischemia-related increases in blood-brain barrier permeability by inhibiting IL-6 and modulates tight junction proteins after ischemia. PMID:25609424

  13. Evaluation of blood-brain barrier-stealth nanocomposites for in situ glioblastoma theranostics applications

    NASA Astrophysics Data System (ADS)

    Su, Chia-Hao; Tsai, Ching-Yi; Tomanek, Boguslaw; Chen, Wei-Yu; Cheng, Fong-Yu

    2016-04-01

    The blood-brain barrier (BBB) is a physiological structure of the blood vessels in the brain. The BBB efficiently traps most therapeutic drugs in the blood vessels and stops them from entering the brain tissue, resulting in a decreased therapeutic efficiency. In this study, we developed BBB-stealth nanocomposites composed of iron oxide (Fe3O4) nanoparticles (NPs) as a safe nanocarrier for glioblastoma therapy. We showed the antitumor activity of Dox/alg-Fe3O4 NPs using in vitro and in vivo tests. We demonstrated that G23-alg-Fe3O4 NPs crossed the BBB and entered the brain. In situ glioblastoma tumor-bearing mice were used to successfully evaluate the antitumor activity of G23-Dox/alg-Fe3O4 NPs. Magnetic resonance imaging (MRI) and bioluminescence imaging (BLI) confirmed the BBB crossing. The BBB-stealth nanocomposites show great potential for a proof-of-concept clinical trial as a theranostics platform for human brain tumor therapy.The blood-brain barrier (BBB) is a physiological structure of the blood vessels in the brain. The BBB efficiently traps most therapeutic drugs in the blood vessels and stops them from entering the brain tissue, resulting in a decreased therapeutic efficiency. In this study, we developed BBB-stealth nanocomposites composed of iron oxide (Fe3O4) nanoparticles (NPs) as a safe nanocarrier for glioblastoma therapy. We showed the antitumor activity of Dox/alg-Fe3O4 NPs using in vitro and in vivo tests. We demonstrated that G23-alg-Fe3O4 NPs crossed the BBB and entered the brain. In situ glioblastoma tumor-bearing mice were used to successfully evaluate the antitumor activity of G23-Dox/alg-Fe3O4 NPs. Magnetic resonance imaging (MRI) and bioluminescence imaging (BLI) confirmed the BBB crossing. The BBB-stealth nanocomposites show great potential for a proof-of-concept clinical trial as a theranostics platform for human brain tumor therapy. Electronic supplementary information (ESI) available: Experimental details. See DOI: 10.1039/c6nr00280c

  14. Glioma targeting and blood-brain barrier penetration by dual-targeting doxorubincin liposomes.

    PubMed

    Gao, Jian-Qing; Lv, Qing; Li, Li-Ming; Tang, Xin-Jiang; Li, Fan-Zhu; Hu, Yu-Lan; Han, Min

    2013-07-01

    Effective chemotherapy for glioblastoma requires a carrier that can penetrate the blood-brain barrier (BBB) and subsequently target the glioma cells. Dual-targeting doxorubincin (Dox) liposomes were produced by conjugating liposomes with both folate (F) and transferrin (Tf), which were proven effective in penetrating the BBB and targeting tumors, respectively. The liposome was characterized by particle size, Dox entrapment efficiency, and in vitro release profile. Drug accumulation in cells, P-glycoprotein (P-gp) expression, and drug transport across the BBB in the dual-targeting liposome group were examined by using bEnd3 BBB models. In vivo studies demonstrated that the dual-targeting Dox liposomes could transport across the BBB and mainly distribute in the brain glioma. The anti-tumor effect of the dual-targeting liposome was also demonstrated by the increased survival time, decreased tumor volume, and results of both hematoxylin-eosin staining and terminal deoxynucleotidyl transferase dUTP nick end labeling analysis. The dual-targeting Dox liposome could improve the therapeutic efficacy of brain glioma and were less toxic than the Dox solution, showing a dual-targeting effect. These results indicate that this dual-targeting liposome can be used as a potential carrier for glioma chemotherapy. PMID:23628475

  15. Disruption of astrocyte-vascular coupling and the blood-brain barrier by invading glioma cells

    PubMed Central

    Watkins, Stacey; Robel, Stefanie; Kimbrough, Ian F.; Robert, Stephanie M.; Ellis-Davies, Graham; Sontheimer, Harald

    2014-01-01

    Astrocytic endfeet cover the entire cerebral vasculature and serve as exchange sites for ions, metabolites, and energy substrates from the blood to the brain. They maintain endothelial tight junctions that form the blood-brain barrier (BBB) and release vasoactive molecules that regulate vascular tone. Malignant gliomas are highly invasive tumors that use the perivascular space for invasion and co-opt existing vessels as satellite tumors form. Here we use a clinically relevant mouse model of glioma and find that glioma cells, as they populate the perivascular space of pre-existing vessels, displace astrocytic endfeet from endothelial or vascular smooth muscle cells. This causes a focal breach in the BBB. Furthermore, astrocyte-mediated gliovascular coupling is lost, and glioma cells seize control over regulation of vascular tone through Ca2+-dependent release of K+. These findings have important clinical implications regarding blood flow in the tumor-associated brain and the ability to locally deliver chemotherapeutic drugs in disease. PMID:24943270

  16. Quorum Sensing Peptides Selectively Penetrate the Blood-Brain Barrier

    PubMed Central

    Wynendaele, Evelien; Verbeke, Frederick; Stalmans, Sofie; Gevaert, Bert; Janssens, Yorick; Van De Wiele, Christophe; Peremans, Kathelijne; Burvenich, Christian; De Spiegeleer, Bart

    2015-01-01

    Bacteria communicate with each other by the use of signaling molecules, a process called ‘quorum sensing’. One group of quorum sensing molecules includes the oligopeptides, which are mainly produced by Gram-positive bacteria. Recently, these quorum sensing peptides were found to biologically influence mammalian cells, promoting i.a. metastasis of cancer cells. Moreover, it was found that bacteria can influence different central nervous system related disorders as well, e.g. anxiety, depression and autism. Research currently focuses on the role of bacterial metabolites in this bacteria-brain interaction, with the role of the quorum sensing peptides not yet known. Here, three chemically diverse quorum sensing peptides were investigated for their brain influx (multiple time regression technique) and efflux properties in an in vivo mouse model (ICR-CD-1) to determine blood-brain transfer properties: PhrCACET1 demonstrated comparatively a very high initial influx into the mouse brain (Kin = 20.87 μl/(g×min)), while brain penetrabilities of BIP-2 and PhrANTH2 were found to be low (Kin = 2.68 μl/(g×min)) and very low (Kin = 0.18 μl/(g×min)), respectively. All three quorum sensing peptides were metabolically stable in plasma (in vitro) during the experimental time frame and no significant brain efflux was observed. Initial tissue distribution data showed remarkably high liver accumulation of BIP-2 as well. Our results thus support the potential role of some quorum sensing peptides in different neurological disorders, thereby enlarging our knowledge about the microbiome-brain axis. PMID:26536593

  17. Atomistic modeling of the structural components of the blood-brain barrier

    NASA Astrophysics Data System (ADS)

    Glukhova, O. E.; Grishina, O. A.; Slepchenkov, M. M.

    2015-03-01

    Blood-brain barrier, which is a barrage system between the brain and blood vessels, plays a key role in the "isolation" of the brain of unnecessary information, and reduce the "noise" in the interneuron communication. It is known that the barrier function of the BBB strictly depends on the initial state of the organism and changes significantly with age and, especially in developing the "vascular accidents". Disclosure mechanisms of regulation of the barrier function will develop new ways to deliver neurotrophic drugs to the brain in the newborn. The aim of this work is the construction of atomistic models of structural components of the blood-brain barrier to reveal the mechanisms of regulation of the barrier function.

  18. A method to determine the ability of drugs to diffuse through the blood-brain barrier.

    PubMed Central

    Seelig, A; Gottschlich, R; Devant, R M

    1994-01-01

    A method has been devised for predicting the ability of drugs to cross the blood-brain barrier. The criteria depend on the amphiphilic properties of a drug as reflected in its surface activity. The assessment was made with various drugs that either penetrate or do not penetrate the blood-brain barrier. The surface activity of these drugs was quantified by their Gibbs adsorption isotherms in terms of three parameters: (i) the onset of surface activity, (ii) the critical micelle concentration, and (iii) the surface area requirement of the drug at the air/water interface. A calibration diagram is proposed in which the critical micelle concentration is plotted against the concentration required for the onset of surface activity. Three different regions are easily distinguished in this diagram: a region of very hydrophobic drugs which fail to enter the central nervous system because they remain adsorbed to the membrane, a central area of less hydrophobic drugs which can cross the blood-brain barrier, and a region of relatively hydrophilic drugs which do not cross the blood-brain barrier unless applied at high concentrations. This diagram can be used to predict reliably the central nervous system permeability of an unknown compound from a simple measurement of its Gibbs adsorption isotherm. PMID:8278409

  19. Blood-Brain Barrier Permeability and Monocyte Infiltration in Experimental Allergic Encephalomyelitis

    ERIC Educational Resources Information Center

    Floris, S.; Blezer, E. L. A.; Schreibelt, G.; Dopp, E.; van der Pol, S. M. A.; Schadee-Eestermans, I. L.; Nicolay, K.; Dijkstra, C. D.; de Vries, H. E.

    2004-01-01

    Enhanced cerebrovascular permeability and cellular infiltration mark the onset of early multiple sclerosis lesions. So far, the precise sequence of these events and their role in lesion formation and disease progression remain unknown. Here we provide quantitative evidence that blood-brain barrier leakage is an early event and precedes massive…

  20. Penetrating the Blood-Brain Barrier: Promise of Novel Nanoplatforms and Delivery Vehicles.

    PubMed

    Ali, Iqbal Unnisa; Chen, Xiaoyuan

    2015-10-27

    Multifunctional nanoplatforms combining versatile therapeutic modalities with a variety of imaging options have the potential to diagnose, monitor, and treat brain diseases. The promise of nanotechnology can only be realized by the simultaneous development of innovative brain-targeting delivery vehicles capable of penetrating the blood-brain barrier without compromising its structural integrity. PMID:26406936

  1. Focused Ultrasound-Induced Neurogenesis Requires an Increase in Blood-Brain Barrier Permeability

    PubMed Central

    Mooney, Skyler J.; Shah, Kairavi; Yeung, Sharon; Burgess, Alison; Aubert, Isabelle; Hynynen, Kullervo

    2016-01-01

    Transcranial focused ultrasound technology used to transiently open the blood-brain barrier, is capable of stimulating hippocampal neurogenesis; however, it is not yet known what aspects of the treatment are necessary for enhanced neurogenesis to occur. The present study set out to determine whether the opening of blood-brain barrier, the specific pressure amplitudes of focused ultrasound, and/or the intravenous administration of microbubbles (phospholipid microspheres) are necessary for the enhancement of neurogenesis. Specifically, mice were exposed to burst (10ms, 1Hz burst repetition frequency) focused ultrasound at the frequency of 1.68MHz and with 0.39, 0.78, 1.56 and 3.0MPa pressure amplitudes. These treatments were also conducted with or without microbubbles, at 0.39 + 0.78MPa or 1.56 + 3.0MPa, respectively. Only focused ultrasound at the ~0.78 MPa pressure amplitude with microbubbles promoted hippocampal neurogenesis and was associated with an increase in blood-brain barrier permeability. These results suggest that focused ultrasound -mediated neurogenesis is dependent upon the opening of the blood-brain barrier. PMID:27459643

  2. Focused Ultrasound-Induced Neurogenesis Requires an Increase in Blood-Brain Barrier Permeability.

    PubMed

    Mooney, Skyler J; Shah, Kairavi; Yeung, Sharon; Burgess, Alison; Aubert, Isabelle; Hynynen, Kullervo

    2016-01-01

    Transcranial focused ultrasound technology used to transiently open the blood-brain barrier, is capable of stimulating hippocampal neurogenesis; however, it is not yet known what aspects of the treatment are necessary for enhanced neurogenesis to occur. The present study set out to determine whether the opening of blood-brain barrier, the specific pressure amplitudes of focused ultrasound, and/or the intravenous administration of microbubbles (phospholipid microspheres) are necessary for the enhancement of neurogenesis. Specifically, mice were exposed to burst (10ms, 1Hz burst repetition frequency) focused ultrasound at the frequency of 1.68MHz and with 0.39, 0.78, 1.56 and 3.0MPa pressure amplitudes. These treatments were also conducted with or without microbubbles, at 0.39 + 0.78MPa or 1.56 + 3.0MPa, respectively. Only focused ultrasound at the ~0.78 MPa pressure amplitude with microbubbles promoted hippocampal neurogenesis and was associated with an increase in blood-brain barrier permeability. These results suggest that focused ultrasound -mediated neurogenesis is dependent upon the opening of the blood-brain barrier. PMID:27459643

  3. Blood-Brain Barrier Breakdown Determines Differential Therapeutic Outcome in Genetically Diverse Forms of Medulloblastoma.

    PubMed

    Guerit, Sylvaine; Liebner, Stefan

    2016-04-11

    Medulloblastoma driven by Wnt/β-catenin and Sonic hedgehog pathway mutations show favorable and poor patient survival upon treatment, respectively. In this Cancer Cell issue, Phoenix and colleagues (2016) report disruption of the blood-brain barrier by Wif1 specifically in Wnt-driven medulloblastoma, resulting in increased treatment response and survival in mouse models. PMID:27070693

  4. Pharmacokinetics of new nootropic acylprolyldipeptide and its penetration across the blood-brain barrier after oral administration.

    PubMed

    Boiko, S S; Ostrovskaya, R U; Zherdev, V P; Korotkov, S A; Gudasheva, T A; Voronina, T A; Seredenin, S B

    2000-04-01

    Pharmacokinetics of GVS-111, a new acylprolyldipeptide with nootropic properties and its penetration across the blood-brain barrier were studied in rats using HPLC. It was found that the dipeptide is absorbed in the gastrointestinal tract, enters the circulation, and penetrates through the blood-brain barrier in an unmodified state. PMID:10977920

  5. Evaluation of blood-brain barrier-stealth nanocomposites for in situ glioblastoma theranostics applications.

    PubMed

    Su, Chia-Hao; Tsai, Ching-Yi; Tomanek, Boguslaw; Chen, Wei-Yu; Cheng, Fong-Yu

    2016-04-14

    The blood-brain barrier (BBB) is a physiological structure of the blood vessels in the brain. The BBB efficiently traps most therapeutic drugs in the blood vessels and stops them from entering the brain tissue, resulting in a decreased therapeutic efficiency. In this study, we developed BBB-stealth nanocomposites composed of iron oxide (Fe3O4) nanoparticles (NPs) as a safe nanocarrier for glioblastoma therapy. We showed the antitumor activity of Dox/alg-Fe3O4 NPs using in vitro and in vivo tests. We demonstrated that G23-alg-Fe3O4 NPs crossed the BBB and entered the brain. In situ glioblastoma tumor-bearing mice were used to successfully evaluate the antitumor activity of G23-Dox/alg-Fe3O4 NPs. Magnetic resonance imaging (MRI) and bioluminescence imaging (BLI) confirmed the BBB crossing. The BBB-stealth nanocomposites show great potential for a proof-of-concept clinical trial as a theranostics platform for human brain tumor therapy. PMID:27035391

  6. CB2 Receptor Activation Inhibits Melanoma Cell Transmigration through the Blood-Brain Barrier

    PubMed Central

    Haskó, János; Fazakas, Csilla; Molnár, Judit; Nyúl-Tóth, Ádám; Herman, Hildegard; Hermenean, Anca; Wilhelm, Imola; Persidsky, Yuri; Krizbai, István A.

    2014-01-01

    During parenchymal brain metastasis formation tumor cells need to migrate through cerebral endothelial cells, which form the morphological basis of the blood-brain barrier (BBB). The mechanisms of extravasation of tumor cells are highly uncharacterized, but in some aspects recapitulate the diapedesis of leukocytes. Extravasation of leukocytes through the BBB is decreased by the activation of type 2 cannabinoid receptors (CB2); therefore, in the present study we sought to investigate the role of CB2 receptors in the interaction of melanoma cells with the brain endothelium. First, we identified the presence of CB1, CB2(A), GPR18 (transcriptional variant 1) and GPR55 receptors in brain endothelial cells, while melanoma cells expressed CB1, CB2(A), GPR18 (transcriptional variants 1 and 2), GPR55 and GPR119. We observed that activation of CB2 receptors with JWH-133 reduced the adhesion of melanoma cells to the layer of brain endothelial cells. JWH-133 decreased the transendothelial migration rate of melanoma cells as well. Our results suggest that changes induced in endothelial cells are critical in the mediation of the effect of CB2 agonists. Our data identify CB2 as a potential target in reducing the number of brain metastastes originating from melanoma. PMID:24815068

  7. MANGANESE TOXICOKINETICS AT THE BLOOD-BRAIN BARRIER

    EPA Science Inventory

    Investigators expect to study the mechanisms by which manganese enters and leaves the brain across the blood–brain barrier and, in particular, whether transporter molecules are involved. The investigators plan to use in vivo brain perfusion in rats as well as in vitro...

  8. Retention of indocyanine green as a potential marker for optical detection of blood brain barrier disruption

    NASA Astrophysics Data System (ADS)

    Ergin, A.; Joshi, S.; Wang, M.; Bigio, I. J.

    2011-03-01

    Preliminary studies have shown that there is great variability in the degree of disruption of blood-brain barrier (BBBD) after the intraarterial injection of mannitol in rabbit models. The disruption of blood-brain barrier (BBB) is affected by a number of factors, and the variations could have a profound impact on regional delivery of chemotherapeutics. Optically measured brain tissue concentrations of indocyanine green (ICG) and Evan's blue (EB) enable the quantification of BBBD after intraarterial administration of mannitol. Using the optical pharmacokinetics technique, a variation of diffuse reflectance spectroscopy, we are able to track in vivo brain tissue concentrations of ICG and EB in rabbits, before and after barrier disruption. This study shows the feasibility of optical monitoring of BBBD, a method that can help improve intraarterial delivery of chemotherapeutic drugs.

  9. Clinical trial of blood-brain barrier disruption by pulsed ultrasound.

    PubMed

    Carpentier, Alexandre; Canney, Michael; Vignot, Alexandre; Reina, Vincent; Beccaria, Kevin; Horodyckid, Catherine; Karachi, Carine; Leclercq, Delphine; Lafon, Cyril; Chapelon, Jean-Yves; Capelle, Laurent; Cornu, Philippe; Sanson, Marc; Hoang-Xuan, Khê; Delattre, Jean-Yves; Idbaih, Ahmed

    2016-06-15

    The blood-brain barrier (BBB) limits the delivery of systemically administered drugs to the brain. Methods to circumvent the BBB have been developed, but none are used in standard clinical practice. The lack of adoption of existing methods is due to procedural invasiveness, serious adverse effects, and the complications associated with performing such techniques coincident with repeated drug administration, which is customary in chemotherapeutic protocols. Pulsed ultrasound, a method for disrupting the BBB, was shown to effectively increase drug concentrations and to slow tumor growth in preclinical studies. We now report the interim results of an ultrasound dose-escalating phase 1/2a clinical trial using an implantable ultrasound device system, SonoCloud, before treatment with carboplatin in patients with recurrent glioblastoma (GBM). The BBB of each patient was disrupted monthly using pulsed ultrasound in combination with systemically injected microbubbles. Contrast-enhanced magnetic resonance imaging (MRI) indicated that the BBB was disrupted at acoustic pressure levels up to 1.1 megapascals without detectable adverse effects on radiologic (MRI) or clinical examination. Our preliminary findings indicate that repeated opening of the BBB using our pulsed ultrasound system, in combination with systemic microbubble injection, is safe and well tolerated in patients with recurrent GBM and has the potential to optimize chemotherapy delivery in the brain. PMID:27306666

  10. Systemic delivery of blood-brain barrier-targeted polymeric nanoparticles enhances delivery to brain tissue.

    PubMed

    Saucier-Sawyer, Jennifer K; Deng, Yang; Seo, Young-Eun; Cheng, Christopher J; Zhang, Junwei; Quijano, Elias; Saltzman, W Mark

    2015-01-01

    Delivery of therapeutic agents to the central nervous system is a significant challenge, hindering progress in the treatment of diseases such as glioblastoma. Due to the presence of the blood-brain barrier (BBB), therapeutic agents do not readily transverse the brain endothelium to enter the parenchyma. Previous reports suggest that surface modification of polymer nanoparticles (NPs) can improve their ability to cross the BBB, but it is unclear whether the observed enhancements in transport are large enough to enhance therapy. In this study, we synthesized two degradable polymer NP systems surface-modified with ligands previously suggested to improve BBB transport, and tested their ability to cross the BBB after intravenous injection in mice. All the NP preparations were able to cross the BBB, although generally in low amounts (<0.5% of the injected dose), which was consistent with prior reports. One NP produced significantly higher brain uptake (∼0.8% of the injected dose): a block copolymer of polylactic acid and hyperbranched polyglycerol, surface modified with adenosine (PLA-HPG-Ad). PLA-HPG-Ad NPs provided controlled release of camptothecin, killing U87 glioma cells in culture. When administered intravenously in mice with intracranial U87 tumors, they failed to increase survival. These results suggest that enhancing NP transport across the BBB does not necessarily yield proportional pharmacological effects. PMID:26453169

  11. Characterization and Optimization of Trans-Blood-Brain Barrier Diffusion In Vivo

    NASA Astrophysics Data System (ADS)

    Konofagou, Elisa E.; Choi, James; Baseri, Babak; Lee, Ann

    2009-04-01

    Current treatments of neurological and neurodegenerative diseases are limited due to the lack of a truly noninvasive, transient, and regionally selective brain drug delivery method. The brain is particularly difficult to deliver drugs to because of the blood-brain barrier (BBB). Over the past few years, we have been developing methods that combine Focused Ultrasound (FUS) and microbubbles in order to noninvasively, locally and transiently open the BBB so as to treat neurodegenerative diseases. In this paper, we will focus on the characterization of the type of molecular delivery that can be induced through the opened BBB. More specifically, we will characterize important properties of the BBB opening such as its reversibility and permeability using fluorescence and MR imaging techniques, respectively. Results on both wildtype and Alzheimer's model mice showed that the timeline of BBB opening is very similar between the presence and absence of amyloid plaques. The permeability change induced by BBB opening was found to increase by up to a 10-fold and to similar levels with those found in literature for glioma tumors.

  12. Systemic Delivery of Blood-Brain Barrier Targeted Polymeric Nanoparticles Enhances Delivery to Brain Tissue

    PubMed Central

    Saucier-Sawyer, Jennifer K.; Deng, Yang; Seo, Young-Eun; Cheng, Christopher J.; Zhang, Junwei; Quijano, Elias; Saltzman, W. Mark

    2016-01-01

    Delivery of therapeutic agents to the central nervous system is a significant challenge, hindering progress in the treatment of diseases such as glioblastoma. Due to the presence of the blood-brain barrier (BBB), therapeutic agents do not readily transverse the brain endothelium to enter the parenchyma. Previous reports suggest that surface modification of polymer nanoparticles can improve their ability to cross the BBB, but it is unclear whether the observed enhancements in transport are large enough to enhance therapy. In this study, we synthesized two degradable polymer nanoparticle systems surface-modified with ligands previously suggested to improve BBB transport, and tested their ability to cross the BBB after intravenous injection in mice. All nanoparticle preparations were able to cross the BBB, although generally in low amounts (<0.5% of the injected dose), which was consistent with prior reports. One nanoparticle produced significantly higher brain uptake (~0.8% of the injected dose): a block copolymer of polylactic acid and hyperbranched polyglycerol, surface modified with adenosine (PLA-HPG-Ad). PLA-HPG-Ad nanoparticles provided controlled release of camptothecin, killing U87 glioma cells in culture. When administered intravenously in mice with intracranial U87 tumors, they failed to increase survival. These results suggest that enhancing nanoparticle transport across the BBB does not necessarily yield proportional pharmacological effects. PMID:26453169

  13. Interferon-λ restricts West Nile virus neuroinvasion by tightening the blood-brain barrier

    PubMed Central

    Lazear, Helen M.; Daniels, Brian P.; Pinto, Amelia K.; Huang, Albert C.; Vick, Sarah C.; Doyle, Sean E.; Gale, Michael; Klein, Robyn S.; Diamond, Michael S.

    2015-01-01

    Although interferon-λ [also known as type III interferon or interleukin-28 (IL-28)/IL-29] restricts infection by several viruses, its inhibitory mechanism has remained uncertain. We used recombinant interferon-λ and mice lacking the interferon-λ receptor (IFNLR1) to evaluate the effect of interferon-λ on infection with West Nile virus, an encephalitic flavivirus. Cell culture studies in mouse keratinocytes and dendritic cells showed no direct antiviral effect of exogenous interferon-λ, even though expression of interferon-stimulated genes was induced. We observed no differences in West Nile virus burden between wild-type and Ifnlr1−/− mice in the draining lymph nodes, spleen, or blood. We detected increased West Nile virus infection in the brain and spinal cord of Ifnlr1−/− mice, yet this was not associated with a direct antiviral effect in mouse neurons. Instead, we observed an increase in blood-brain barrier permeability in Ifnlr1−/− mice. Treatment of mice with pegylated interferon-λ2 resulted in decreased blood-brain barrier permeability, reduced West Nile virus infection in the brain without affecting viremia, and improved survival against lethal virus challenge. An in vitro model of the blood-brain barrier showed that interferon-λ signaling in mouse brain microvascular endothelial cells increased transendothelial electrical resistance, decreased virus movement across the barrier, and modulated tight junction protein localization in a protein synthesis– and signal transducer and activator of transcription 1 (STAT1)–independent manner. Our data establish an indirect antiviral function of interferon-λ in which noncanonical signaling through IFNLR1 tightens the blood-brain barrier and restricts viral neuroinvasion and pathogenesis. PMID:25904743

  14. A dynamic model of the blood-brain barrier "in vitro".

    PubMed

    Stanness, K A; Guatteo, E; Janigro, D

    1996-01-01

    Cell culture models have been widely used for screening of neurotoxicants and represent a viable alternative to direct in vivo experiments. We have developed a dynamic in vitro blood-brain barrier model designed to allow for extensive toxicological, pharmacological and physiological testing. Induction of blood-brain barrier properties in a tri-dimensional hollow fiber culturing apparatus was investigated by co-culturing a bovine aortic endothelial cell line (or rat brain endothelial cells) with rat brain astrocytes (or C6 rat glioma cells) under pulsatile flow conditions to mimic intraluminal blood flow. Cell growth was monitored over time by measuring glucose consumption and lactate production: these experiments confirmed that the hollow fiber cell culturing systems can maintain viable cells in culture for extended (> 1 month) periods of time. Cells were visually inspected after culturing and dissociation from the hollow fiber cartridge and identified as endothelial (by fluorescent Dil-Ac-LDL uptake) or glial (by GFAP immunoreactivity). Blood-brain barrier properties were tested by intraluminal injection of horse-radish peroxidase (HRP, mol. weight 44,000), glucose (m.w. 180) or potassium. Either procedure demonstrated that aortic cells co-cultured with astrocytes (or C6 cells) developed a selective barrier with an estimated electrical resistance of 2,900 omega/cm2. The electrophysiological and morphological properties of BAEC were also affected by the co-culturing process, suggesting that astrocytes induced CNS properties in these cells. These results demonstrate that the hollow fiber cell co-culturing system may be used as a dynamic model of the mammalian blood-brain barrier. PMID:8856743

  15. Interferon-λ restricts West Nile virus neuroinvasion by tightening the blood-brain barrier.

    PubMed

    Lazear, Helen M; Daniels, Brian P; Pinto, Amelia K; Huang, Albert C; Vick, Sarah C; Doyle, Sean E; Gale, Michael; Klein, Robyn S; Diamond, Michael S

    2015-04-22

    Although interferon-λ [also known as type III interferon or interleukin-28 (IL-28)/IL-29] restricts infection by several viruses, its inhibitory mechanism has remained uncertain. We used recombinant interferon-λ and mice lacking the interferon-λ receptor (IFNLR1) to evaluate the effect of interferon-λ on infection with West Nile virus, an encephalitic flavivirus. Cell culture studies in mouse keratinocytes and dendritic cells showed no direct antiviral effect of exogenous interferon-λ, even though expression of interferon-stimulated genes was induced. We observed no differences in West Nile virus burden between wild-type and Ifnlr1(-/-) mice in the draining lymph nodes, spleen, or blood. We detected increased West Nile virus infection in the brain and spinal cord of Ifnlr1(-/-) mice, yet this was not associated with a direct antiviral effect in mouse neurons. Instead, we observed an increase in blood-brain barrier permeability in Ifnlr1(-/-) mice. Treatment of mice with pegylated interferon-λ2 resulted in decreased blood-brain barrier permeability, reduced West Nile virus infection in the brain without affecting viremia, and improved survival against lethal virus challenge. An in vitro model of the blood-brain barrier showed that interferon-λ signaling in mouse brain microvascular endothelial cells increased transendothelial electrical resistance, decreased virus movement across the barrier, and modulated tight junction protein localization in a protein synthesis- and signal transducer and activator of transcription 1 (STAT1)-independent manner. Our data establish an indirect antiviral function of interferon-λ in which noncanonical signaling through IFNLR1 tightens the blood-brain barrier and restricts viral neuroinvasion and pathogenesis. PMID:25904743

  16. Drug Delivery Systems, CNS Protection, and the Blood Brain Barrier

    PubMed Central

    Upadhyay, Ravi Kant

    2014-01-01

    Present review highlights various drug delivery systems used for delivery of pharmaceutical agents mainly antibiotics, antineoplastic agents, neuropeptides, and other therapeutic substances through the endothelial capillaries (BBB) for CNS therapeutics. In addition, the use of ultrasound in delivery of therapeutic agents/biomolecules such as proline rich peptides, prodrugs, radiopharmaceuticals, proteins, immunoglobulins, and chimeric peptides to the target sites in deep tissue locations inside tumor sites of brain has been explained. In addition, therapeutic applications of various types of nanoparticles such as chitosan based nanomers, dendrimers, carbon nanotubes, niosomes, beta cyclodextrin carriers, cholesterol mediated cationic solid lipid nanoparticles, colloidal drug carriers, liposomes, and micelles have been discussed with their recent advancements. Emphasis has been given on the need of physiological and therapeutic optimization of existing drug delivery methods and their carriers to deliver therapeutic amount of drug into the brain for treatment of various neurological diseases and disorders. Further, strong recommendations are being made to develop nanosized drug carriers/vehicles and noninvasive therapeutic alternatives of conventional methods for better therapeutics of CNS related diseases. Hence, there is an urgent need to design nontoxic biocompatible drugs and develop noninvasive delivery methods to check posttreatment clinical fatalities in neuropatients which occur due to existing highly toxic invasive drugs and treatment methods. PMID:25136634

  17. Disruption of the blood brain barrier following ALA mediated photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Hirschberg, Henry; Peng, Qian; Uzal, Francisco A.; Chighvinadze, David; Zhang, Michelle J.; Madsen, Steen J.

    2008-02-01

    Introduction: Failure of treatment for high grade gliomas is usually due to local recurrence at the site of surgical resection indicating that a more aggressive form of local therapy, such as PDT, could be of benefit. PDT causes damage to tumor cells as well as degradation of the blood brain barrier (BBB). We have evaluated the ability of ALA mediated PDT to open the BBB in rats. This will permit access of chemotherapeutic agents to brain tumor cells remaining in the resection cavity wall, but limit their penetration into normal brain remote from the site of illumination. Materials and Methods: ALA-PDT was performed on non tumor bearing inbred Fisher rats at increasing fluence levels. T2 weighted MRI scans were used to evaluate edema formation and post-contrast T I MRI scans were used to monitor the degree BBB disruption which could be inferred from the intensity and volume of the contrast agent visualized. Results. PDT at increasing fluence levels between 9J and 26J demonstrated an increasing contrast flow rate. No effect on the BBB was observed if 26J of light were given in the absence of ALA. A similar increased contrast volume was observed with increasing fluence rates. The BBB was found to be disrupted 2hrs. following PDT and 80-100% restored 72hrs later. Conclusion: PDT was highly effective in opening the BBB in a limited region of the brain. The degradation of the BBB was temporary in nature, opening rapidly following treatment and significantly restored during the next 72 hrs.

  18. Selective disruption of the blood-brain barrier by photochemical internalization

    NASA Astrophysics Data System (ADS)

    Hirschberg, Henry; Zhang, Michelle J.; Gach, Michael H.; Uzal, Francisco A.; Chighvinadze, David; Madsen, Steen J.

    2009-02-01

    Introduction: Failure to eradicate infiltrating glioma cells using conventional treatment regimens results in tumor recurrence and is responsible for the dismal prognosis of patients with glioblastoma multiforme (GBM). This is due to the fact that these migratory cells are protected by the blood-brain barrier (BBB) which prevents the delivery of most anti-cancer agents. We have evaluated the ability of photochemical internalization (PCI) to selectively disrupt the BBB in rats. This will permit access of anti-cancer drugs to effectively target the infiltrating tumor cells, and potentially improve the treatment effectiveness for malignant gliomas. Materials and Methods: PCI treatment, coupling a macromolecule therapy of Clostridium perfringens (Cl p) epsilon prototoxin with AlPcS2a-PDT, was performed on non-tumor bearing inbred Fisher rats. T1-weighted post-contrast magnetic resonance imaging (MRI) scans were used to evaluate the extent of BBB disruption which can be inferred from the volume contrast enhancement. Results: The synergistic effect of PCI to disrupt the BBB was observed at a fluence level of 1 J with an intraperitoneal injection of Cl p prototoxin. At the fluence level of 2.5J, the extent of BBB opening induced by PCI was similar to the result of PDT suggesting no synergistic effect evoked under these conditions. Conclusion: PCI was found to be highly effective and efficient for inducing selective and localized disruption of the BBB. The extent of BBB opening peaked on day 3 and the BBB was completed restored by day 18 post treatment.

  19. Blood-brain barrier permeability of bioactive withanamides present in Withania somnifera fruit extract.

    PubMed

    Vareed, Shaiju K; Bauer, Alison K; Nair, Kavitha M; Liu, Yunbao; Jayaprakasam, Bolleddula; Nair, Muraleedharan G

    2014-08-01

    The neuroprotective effect of Withania somnifera L. Dunal fruit extract, in rodent models, is known. Withanamides, the primary active constituents in W.somnifera fruit extract exhibited neuroprotective effects against β-amyloid-induced cytotoxicity in neuronal cell culture studies. Therefore, we investigated the blood-brain barrier permeability of withanamides in W.somnifera fruit extract in mice using HPLC coupled with high resolution quadrupole time of flight mass spectrometer (Q-TOF/MS) detection. Mice were administered with 250 mg/kg of W.somnifera extract by intraperitoneal injection, and the blood and brain samples analyzed by Q-TOF/MS detection. Four major withanamides were detected in brain and blood of mice administered with W.somnifera extract. The results suggested that the withanamides crossed the blood-brain barrier. These results may help to develop W.somnifera fruit extract as a preventive or therapeutic botanical drug for stress-induced neurological disorders. PMID:24458838

  20. Next generation of non-mammalian blood-brain barrier models to study parasitic infections of the central nervous system

    PubMed Central

    Siddiqui, Ruqaiyyah; Edwards-Smallbone, James; Flynn, Robin; Khan, Naveed Ahmed

    2012-01-01

    Transmigration of neuropathogens across the blood-brain barrier is a key step in the development of central nervous system infections, making it a prime target for drug development. The ability of neuropathogens to traverse the blood-brain barrier continues to inspire researchers to understand the specific strategies and molecular mechanisms that allow them to enter the brain. The availability of models of the blood-brain barrier that closely mimic the situation in vivo offers unprecedented opportunities for the development of novel therapeutics. PMID:21921682

  1. Evaluation of blood-brain barrier permeability changes in rhesus monkeys and man using 82Rb and positron emission tomography

    SciTech Connect

    Yen, C.K.; Budinger, T.F.

    1981-12-01

    Dynamic positron tomography of the brain with /sup 82/Rb, obtained from a portable generator (/sup 82/Sr (25 days) - /sup 82/Rb (76 sec)), provides a means of studying blood-brain barrier (BBB) permeability in physiological and clinical investigations. The BBB in rhesus monkeys was opened unilaterally be intracarotid infusion of 3 M urea. This osmotic barrier opening allowed entry into the brain of intravenously administered rubidium chloride. The BBB opening was demonstrated noninvasively using /sup 82/Rb and positron emission tomography and corroborated by the accumulation of /sup 86/Rb in tissue samples. Positron emission tomography studies can be repeated every 5 min and indicate that dynamic tomography or static imaging can be used to study BBB permeability changes induced by a wide variety of noxious stimuli. Brain tumors in human subjects are readily detected because of the usual BBB permeability disruption in and around the tumors.

  2. A multitheragnostic nanobubble system to induce blood-brain barrier disruption with magnetically guided focused ultrasound.

    PubMed

    Huang, Hsin-Yang; Liu, Hao-Li; Hsu, Po-Hung; Chiang, Chih-Sheng; Tsai, Chih-Hung; Chi, Huei-Shang; Chen, San-Yuan; Chen, You-Yin

    2015-01-27

    A novel magnetically guidable nanobubble is designed for disrupting the blood-brain barrier (BBB) by combining magnetic guidance with focused ultrasound in vivo. The magnetic-nanobubble platform also demonstrates the potential to serve as a unique theranostic tool via performing focused ultrasound (FUS)-induced BBB disruption and magnetic resonance imaging (MRI)/ultrasound dual-modality contrast-agent imaging to improve the drug delivery of therapeutic substances or gene therapy into the central nervous system. PMID:25472627

  3. Effects of chronic metrifonate treatment on cholinergic enzymes and the blood-brain barrier.

    PubMed

    Rakonczay, Z; Papp, H

    2001-07-01

    After an acute (4 h) treatment with an irreversible cholinesterase inhibitor organophosphate, metrifonate (100 mg/kg i.p.), the activities of both acetyl- and butyrylcholinesterase were inhibited (66.0-70.7% of the control level) in the rat brain cortex and hippocampus. There were no significant changes in the acetyl- and butyrylcholinesterase activities in the olfactory bulb, or in the choline acetyltransferase activity in all three brain areas. After chronic (2 or 5 week) metrifonate treatment (100 mg/kg daily i.p.), the activities of both cholinesterases were substantially inhibited in the rat brain cortex and hippocampus (15.8-31.8% of the control levels), but there was no inhibition of the choline acetyltransferase activity. Moreover, chronic metrifonate treatment did not have any effect on the distribution of the acetylcholinesterase molecular forms. In vitro, metrifonate proved to be a more potent inhibitor of butyryl- than of acetylcholinesterase in both the cortex and the hippocampus. In the hippocampus, the butyrylcholinesterase activity was twice as sensitive to metrifonate inhibition as that in the cortex (IC50 values 0.22 and 0.46 microM, respectively). The effects of chronic (5 week) metrifonate treatment on the blood-brain barrier of the adult rat were examined. The damage to the blood-brain barrier was judged by the extravasation of Evans' blue dye in three brain regions: the cerebral cortex, the hippocampus, and the striatum. No extravasation of Evans' blue dye was found in the brain by fluorometric quantitation. These data indicate that chronic metrifonate treatment may increase the extracellular acetylcholine level via cholinesterase inhibition, but it does not have any effects on the blood-brain barrier. Therefore, it appears reasonable to hypothesize that cholinesterase activities do not play a role in the blood-brain barrier permeability. PMID:11311445

  4. Anti-transferrin receptor antibody and antibody-drug conjugates cross the blood-brain barrier

    SciTech Connect

    Friden, P.M.; Walus, L.R.; Musso, G.F.; Taylor, M.A.; Malfroy, B.; Starzyk, R.M. )

    1991-06-01

    Delivery of nonlipophilic drugs to the brain is hindered by the tightly apposed capillary endothelial cells that make up the blood-brain barrier. The authors have examined the ability of a monoclonal antibody (OX-26), which recognizes the rat transferrin receptor, to function as a carrier for the delivery of drugs across the blood-brain barrier. This antibody, which was previously shown to bind preferentially to capillary endothelial cells in the brain after intravenous administration, labels the entire cerebrovascular bed in a dose-dependent manner. The initially uniform labeling of brain capillaries becomes extremely punctate {approximately} 4 hr after injection, suggesting a time-dependent sequestering of the antibody. Capillary-depletion experiments, in which the brain is separated into capillary and parenchymal fractions, show a time-dependent migration of radiolabeled antibody from the capillaries into the brain parenchyma, which is consistent with the transcytosis of compounds across the blood-brain barrier. Antibody-methotrexate conjugates were tested in vivo to assess the carrier ability of this antibody. Immunohistochemical staining for either component of an OX-26-methotrexate conjugate revealed patterns of cerebrovascular labeling identical to those observed with the unaltered antibody. Accumulation of radiolabeled methotrexate in the brain parenchyma is greatly enhanced when the drug is conjugated to OX-26.

  5. In vitro screening of nanomedicines through the blood brain barrier: A critical review.

    PubMed

    Aparicio-Blanco, Juan; Martín-Sabroso, Cristina; Torres-Suárez, Ana-Isabel

    2016-10-01

    The blood-brain barrier accounts for the high attrition rate of the treatments of most brain disorders, which therefore remain one of the greatest health-care challenges of the twenty first century. Against this background of hindrance to brain delivery, nanomedicine takes advantage of the assembly at the nanoscale of available biomaterials to provide a delivery platform with potential to raising brain levels of either imaging or therapeutic agents. Nevertheless, to prevent later failure due to ineffective drug levels at the target site, researchers have been endeavoring to develop a battery of in vitro screening procedures that can predict earlier in the drug discovery process the ability of these cutting-edge drug delivery platforms to cross the blood-brain barrier for biomedical purposes. This review provides an in-depth analysis of the currently available in vitro blood-brain barrier models (both cell-based and non-cell-based) with the focus on their suitability for understanding the biological brain distribution of forthcoming nanomedicines. The relationship between experimental factors and underlying physiological assumptions that would ultimately lead to a more predictive capacity of their in vivo performance, and those methods already assayed for the evaluation of the brain distribution of nanomedicines are comprehensively discussed. PMID:27392291

  6. Minocycline ameliorates prenatal valproic acid induced autistic behaviour, biochemistry and blood brain barrier impairments in rats.

    PubMed

    Kumar, Hariom; Sharma, Bhupesh

    2016-01-01

    Autism is a neurodevelopment disorder. One percent worldwide population suffers with autism and males suffer more than females. Microglia plays an important role in neurodevelopment, neuropsychiatric and neurodegenerative disorders. The present study has been designed to investigate the role of minocycline in prenatal valproic acid induced autism in rats. Animals with prenatal valproic acid have reduced social interaction (three chamber social behaviour apparatus), spontaneous alteration (Y-Maze), exploratory activity (Hole board test), intestinal motility, serotonin levels (both in prefrontal cortex and ileum) and prefrontal cortex mitochondrial complex activity (complexes I, II, IV). Furthermore, prenatal valproic acid treated animals have shown an increase in locomotion (actophotometer), anxiety (elevated plus maze), brain oxidative stress (thiobarbituric acid reactive species, glutathione, catalase), nitrosative stress (nitrite/nitrate), inflammation (both in brain and ileum myeloperoxidase activity), calcium and blood brain barrier permeability. Treatment with minocycline significantly attenuated prenatal valproic acid induced reduction in social interaction, spontaneous alteration, exploratory activity intestinal motility, serotonin levels and prefrontal cortex mitochondrial complex activity. Furthermore, minocycline has also attenuated prenatal valproic acid induced increase in locomotion, anxiety, brain oxidative and nitrosative stress, inflammation, calcium and blood brain barrier permeability. Thus, it may be concluded that prenatal valproic acid has induced autistic behaviour, biochemistry and blood brain barrier impairment in animals, which were significantly attenuated by minocycline. Minocycline should be explored further for its therapeutic benefits in autism. PMID:26551768

  7. Hypomyelination, memory impairment, and blood-brain barrier permeability in a model of sleep apnea.

    PubMed

    Kim, Lenise Jihe; Martinez, Denis; Fiori, Cintia Zappe; Baronio, Diego; Kretzmann, Nélson Alexandre; Barros, Helena Maria Tannhauser

    2015-02-01

    We investigated the effect of intermittent hypoxia, mimicking sleep apnea, on axonal integrity, blood-brain barrier permeability, and cognitive function of mice. Forty-seven C57BL mice were exposed to intermittent or sham hypoxia, alternating 30s of progressive hypoxia and 30s of reoxigenation, during 8h/day. The axonal integrity in cerebellum was evaluated by transmission electron microscopy. Short- and long-term memories were assessed by novel object recognition test. The levels of endothelin-1 were measured by ELISA. Blood-brain barrier permeability was quantified by Evans Blue dye. After 14 days, animals exposed to intermittent hypoxia showed hypomyelination in cerebellum white matter and higher serum levels of endothelin-1. The short and long-term memories in novel object recognition test was impaired in the group exposed to intermittent hypoxia as compared to controls. Blood-brain barrier permeability was similar between the groups. These results indicated that hypomyelination and impairment of short- and long-term working memories occurred in C57BL mice after 14 days of intermittent hypoxia mimicking sleep apnea. PMID:25482664

  8. Osmotic blood-brain barrier modification: clinical documentation by enhanced CT scanning and/or radionuclide brain scanning

    SciTech Connect

    Neuwelt, E.A.; Specht, H.D.; Howieson, J.; Haines, J.E.; Bennett, M.J.; Hill, S.A.; Frenkel, E.P.

    1983-10-01

    Results of initial clinical trials of brain tumor chemotherapy after osmotic blood-brain barrier disruption are promising. In general, the procedure is well tolerated. The major complication has been seizures. In this report, data are presented which indicate that the etiology of these seizures is related to the use of contrast agent (meglumine iothalamate) to monitor barrier modification. A series of 19 patients underwent a total of 85 barrier modification procedures. Documentation of barrier disruption was monitored by contrast-enhanced computed tomographic (CT) scanning, radionuclide brain scanning, or a combination of both techniques. In 56 procedures (19 patients) monitored by enhanced CT, seizures occurred a total of 10 times in eight patients. Twenty-three barrier modification procedures (in nine of these 19 patients) documented by nuclear brain scans alone, however, resulted in only one focal motor seizure in each of two patients. In eight of the 19 patients who had seizures after barrier disruption and enhanced CT scan, four subsequently had repeat procedures monitored by radionuclide scan alone. In only one of these patients was further seizure activity noted; a single focal motor seizure was observed. Clearly, the radionuclide brain scan does not have the sensitivity and spatial resolution of enhanced CT, but at present it appears safer to monitor barrier modification by this method and to follow tumor growth between barrier modifications by enhanced CT. Four illustrative cases showing methods, problems, and promising results are presented.

  9. Effect of rapid correction of hyponatremia on the blood-brain barrier of rats.

    PubMed

    Adler, S; Verbalis, J G; Williams, D

    1995-05-01

    Brain demyelination sometimes follows rapid correction of hyponatremia, especially if the hyponatremia is chronic. During correction brain water decreases and the brain shrinks. The present study examined whether such shrinkage might be sufficient to disrupt the tight junctions of the blood-brain barrier. Barrier intactness was evaluated using magnetic resonance imaging and intravenous gadolinium contrast administration. Hypertonic saline infusion rapidly increased the plasma sodium concentration and caused barrier disruption more frequently in chronic than in acute hyponatremic rats. Similar increases in plasma sodium concentration did not disrupt the barrier in normonatremic rats. The disruption appeared to be due to altered plasma osmolality since infusion of hypertonic mannitol, which raised plasma osmolality without changing the plasma sodium concentration, disrupted the barrier in hyponatremic but not normonatremic rats. Moreover, the osmotic threshold for barrier disruption was lowest in chronic hyponatremia, intermediate in acute hyponatremia, and highest in normonatremia. The greater susceptibility to osmotic disruption in chronic hyponatremia suggests that blood-brain barrier disruption may play a significant role in causing the demyelination sometimes found following too rapid correction of hyponatremia, possibly through exposure of oligodendrocytes to plasma macromolecules such as complement. PMID:7648255

  10. Hyperthermic Laser Ablation of Recurrent Glioblastoma Leads to Temporary Disruption of the Peritumoral Blood Brain Barrier

    PubMed Central

    Kim, Michael J.; Campian, Jian L.; Kim, Albert H.; Miller-Thomas, Michelle M.; Shimony, Joshua S.; Tran, David D.

    2016-01-01

    Background Poor central nervous system penetration of cytotoxic drugs due to the blood brain barrier (BBB) is a major limiting factor in the treatment of brain tumors. Most recurrent glioblastomas (GBM) occur within the peritumoral region. In this study, we describe a hyperthemic method to induce temporary disruption of the peritumoral BBB that can potentially be used to enhance drug delivery. Methods Twenty patients with probable recurrent GBM were enrolled in this study. Fourteen patients were evaluable. MRI-guided laser interstitial thermal therapy was applied to achieve both tumor cytoreduction and disruption of the peritumoral BBB. To determine the degree and timing of peritumoral BBB disruption, dynamic contrast-enhancement brain MRI was used to calculate the vascular transfer constant (Ktrans) in the peritumoral region as direct measures of BBB permeability before and after laser ablation. Serum levels of brain-specific enolase, also known as neuron-specific enolase, were also measured and used as an independent quantification of BBB disruption. Results In all 14 evaluable patients, Ktrans levels peaked immediately post laser ablation, followed by a gradual decline over the following 4 weeks. Serum BSE concentrations increased shortly after laser ablation and peaked in 1–3 weeks before decreasing to baseline by 6 weeks. Conclusions The data from our pilot research support that disruption of the peritumoral BBB was induced by hyperthemia with the peak of high permeability occurring within 1–2 weeks after laser ablation and resolving by 4–6 weeks. This provides a therapeutic window of opportunity during which delivery of BBB-impermeant therapeutic agents may be enhanced. Trial Registration ClinicalTrials.gov NCT01851733 PMID:26910903

  11. Osmotic blood-brain barrier modification: clinical documentation by enhanced CT scanning and/or radionuclide brain scanning

    SciTech Connect

    Neuwelt, E.A; Specht, H.D.; Howieson, J.; Haines, J.E.; Bennett, M.J.; Hill, S.A.; Frenkel, E.P.

    1983-10-01

    Results of initial clinical trials of brain tumor chemotherapy after osmotic blood-brain barrier disruption are promising. In general, the procedure is well tolerated. The major complication has been seizures. In this report, data are presented which indicate that the etiology of these seizures is related to the use of contrast agent (meglumine iothalamate) to monitor barrier modification. A series of 19 patients underwent a total of 85 barrier modification procedures. Documentation of barrier disruption was monitored by contrast-enhanced computed tomographic (CT) scanning, radionuclide brain scanning, or a combination of both techniques. In 56 procedures (19 patients) monitored by enhanced CT, seizures occurred a total of 10 times in eight patients. Twenty-three barrier modification procedures (in nine of these 19 patients) documented by nuclear brain scans alone, however, resulted in only one focal motor seizure in each of two patients. Clearly, the radionuclide brain scan does not have the sensitivity and spatial resolution of enhanced CT, but at present it appears safer to monitor barrier modification by this method and to follow tumor growth between barrier modifications by enhanced CT. Four illustrative cases showing methods, problems, and promising results are presented.

  12. Blood-brain barrier and blood-cerebrospinal fluid barrier in normal and pathological conditions.

    PubMed

    Ueno, Masaki; Chiba, Yoichi; Murakami, Ryuta; Matsumoto, Koichi; Kawauchi, Machi; Fujihara, Ryuji

    2016-04-01

    Blood-borne substances can invade into the extracellular spaces of the brain via endothelial cells in sites without the blood-brain barrier (BBB), and can travel through the interstitial fluid (ISF) of the brain parenchyma adjacent to non-BBB sites. It has been shown that cerebrospinal fluid (CSF) drains directly into the blood via the arachnoid villi and also into lymph nodes via the subarachnoid spaces of the brain, while ISF drains into the cervical lymph nodes through perivascular drainage pathways. In addition, the glymphatic pathway of fluids, characterized by para-arterial pathways, aquaporin4-dependent passage through astroglial cytoplasm, interstitial spaces, and paravenous routes, has been established. Meningeal lymphatic vessels along the superior sagittal sinus were very recently discovered. It is known that, in mice, blood-borne substances can be transferred to areas with intact BBB function, such as the medial regions of the hippocampus, presumably through leaky vessels in non-BBB sites. In the present paper, we review the clearance mechanisms of interstitial substances, such as amyloid-β peptides, as well as summarize models of BBB deterioration in response to different types of insults, including acute ischemia followed by reperfusion, hypertension, and chronic hypoperfusion. Lastly, we discuss the relationship between perivascular clearance and brain disorders. PMID:26920424

  13. Permeability of ergot alkaloids across the blood-brain barrier in vitro and influence on the barrier integrity

    PubMed Central

    Mulac, Dennis; Hüwel, Sabine; Galla, Hans-Joachim; Humpf, Hans-Ulrich

    2012-01-01

    Scope Ergot alkaloids are secondary metabolites of Claviceps spp. and they have been in the focus of research for many years. Experiments focusing on ergotamine as a former migraine drug referring to the ability to reach the brain revealed controversial results. The question to which extent ergot alkaloids are able to cross the blood-brain barrier is still not answered. Methods and results In order to answer this question we have studied the ability of ergot alkaloids to penetrate the blood-brain barrier in a well established in vitro model system using primary porcine brain endothelial cells. It could clearly be demonstrated that ergot alkaloids are able to cross the blood-brain barrier in high quantities in only a few hours. We could further identify an active transport for ergometrine as a substrate for the BCRP/ABCG2 transporter. Investigations concerning barrier integrity properties have identified ergocristinine as a potent substance to accumulate in these cells ultimately leading to a weakened barrier function. Conclusion For the first time we could show that the so far as biologically inactive described 8-(S) isomers of ergot alkaloids seem to have an influence on barrier integrity underlining the necessity for a risk assessment of ergot alkaloids in food and feed. PMID:22147614

  14. Transport of treosulfan and temozolomide across an in-vitro blood-brain barrier model.

    PubMed

    Linz, Ute; Hupert, Michelle; Santiago-Schübel, Beatrix; Wien, Sascha; Stab, Julia; Wagner, Sylvia

    2015-08-01

    In vitro, treosulfan (TREO) has shown high effectiveness against malignant gliomas. However, a first clinical trial for newly diagnosed glioblastoma did not show any positive effect. Even though dosing and timing might have been the reasons for this failure, it might also be that TREO does not reach the brain in sufficient amount. Surprisingly, there are no published data on TREO uptake into the brain of patients, despite extensive research on this compound. An in-vitro blood-brain barrier (BBB) model consisting of primary porcine brain capillary endothelial cells was used to determine the transport of TREO across the cell monolayer. Temozolomide (TMZ), the most widely used cytotoxic drug for malignant gliomas, served as a reference. An HPLC-ESI-MS/MS procedure was developed to detect TREO and TMZ in cell culture medium. Parallel to the experimental approach, the permeability of TREO and the reference substance across the in-vitro BBB was estimated on the basis of their physicochemical properties. The detection limit was 30 nmol/l for TREO and 10 nmol/l for TMZ. Drug transport was measured in two directions: influx, apical-to-basolateral (A-to-B), and efflux, basolateral-to-apical (B-to-A). For TREO, the A-to-B permeability was lower (1.6%) than the B-to-A permeability (3.0%). This was in contrast to TMZ, which had higher A-to-B (13.1%) than B-to-A (7.2%) permeability values. The in-vitro BBB model applied simulated the human BBB properly for TMZ. It is, therefore, reasonable to assume that the values for TREO are also meaningful. Considering the lack of noninvasive, significant alternative methods to study transport across the BBB, the porcine brain capillary endothelial cell model was efficient to collect first data for TREO that explain the disappointing clinical results for this drug against cerebral tumors. PMID:25919318

  15. A statistical model describing combined irreversible electroporation and electroporation-induced blood-brain barrier disruption

    PubMed Central

    Sharabi, Shirley; Kos, Bor; Last, David; Guez, David; Daniels, Dianne; Harnof, Sagi; Miklavcic, Damijan

    2016-01-01

    Background Electroporation-based therapies such as electrochemotherapy (ECT) and irreversible electroporation (IRE) are emerging as promising tools for treatment of tumors. When applied to the brain, electroporation can also induce transient blood-brain-barrier (BBB) disruption in volumes extending beyond IRE, thus enabling efficient drug penetration. The main objective of this study was to develop a statistical model predicting cell death and BBB disruption induced by electroporation. This model can be used for individual treatment planning. Material and methods Cell death and BBB disruption models were developed based on the Peleg-Fermi model in combination with numerical models of the electric field. The model calculates the electric field thresholds for cell kill and BBB disruption and describes the dependence on the number of treatment pulses. The model was validated using in vivo experimental data consisting of rats brains MRIs post electroporation treatments. Results Linear regression analysis confirmed that the model described the IRE and BBB disruption volumes as a function of treatment pulses number (r2 = 0.79; p < 0.008, r2 = 0.91; p < 0.001). The results presented a strong plateau effect as the pulse number increased. The ratio between complete cell death and no cell death thresholds was relatively narrow (between 0.88-0.91) even for small numbers of pulses and depended weakly on the number of pulses. For BBB disruption, the ratio increased with the number of pulses. BBB disruption radii were on average 67% ± 11% larger than IRE volumes. Conclusions The statistical model can be used to describe the dependence of treatment-effects on the number of pulses independent of the experimental setup. PMID:27069447

  16. Mfsd2a-based pharmacological strategies for drug delivery across the blood-brain barrier.

    PubMed

    Wang, Jing-Zhang; Xiao, Ning; Zhang, Ying-Zhou; Zhao, Chao-Xian; Guo, Xin-Hua; Lu, Li-Min

    2016-02-01

    The blood-brain barrier (BBB) keeps the central nervous system (CNS) safe from various brain diseases, while the BBB makes it difficult for effective drugs to enter the CNS. Mfsd2a is specifically expressed on the cell membrane of brain-microvascular endothelial cell (BMEC) and is implicated in the delivery of some substances across the BBB. Mfsd2a is the first inhibitor of the transcytosis and the first transporter for lysophosphatidylcholine-docosahexaenoic acid (LPC-DHA) in BMECs. The crucial dual function of Mfsd2a puts forward two kinds of Mfsd2a-based strategies for carrying drugs from blood to the CNS. First, the reversible inhibition of Mfsd2a may temporarily induce a general disinhibition of the transcytosis in BMECs to transport macromolecular drugs across the BBB (Strategy One). Second, Mfsd2a could be used for the transport of some small-molecule drugs chemically coupled to LPC across the BBB (Strategy Two), which is quite similar to the carrier-mediated transport (CMT) via the glucose transporter (GluT1) and the L-type amino acid transporter 1 (LAT1). We here analyze and discuss the clinical significance of the two Mfsd2a-based strategies, including therapeutic potential, available pharmaceuticals, side effects, administration procedures, and disease types. In summary, the regulatory role of Mfsd2a deepens our knowledge of the function of the BBB, potentially contributing to the effective drug delivery in the treatments for neurodegenerative diseases, brain tumors, and life-threatening infections in the CNS. PMID:26747400

  17. The Blood-Brain Barrier Challenge for the Treatment of Brain Cancer, Secondary Brain Metastases, and Neurological Diseases.

    PubMed

    Weidle, Ulrich H; Niewöhner, Jens; Tiefenthaler, Georg

    2015-01-01

    Formation of metastases from various tumor entities in the brain is a major problem for the treatment of advanced cancer. We describe target molecules and tools for the delivery of small molecules or proteins across the blood-brain barrier (BBB), and the treatment of brain tumors and metastases with antibody-related moieties. In addition, drugs preventing formation of metastases or interfering with the growth of established metastases are described, as well as pre-clinical metastasis models and corresponding clinical data. Furthermore, we discuss the delivery of effector proteins and antibody-based moieties fused with an antibody-based scaffold across the BBB in several model systems which might be applicable for the treatment of brain metastases. PMID:26136217

  18. Pathways and Progress in Improving Drug Delivery through the Intestinal Mucosa and Blood-Brain Barriers

    PubMed Central

    Laksitorini, Marlyn; Prasasty, Vivitri D.; Kiptoo, Paul K.; Siahaan, Teruna J.

    2015-01-01

    One of the major hurdles in developing therapeutic agents is the difficulty in delivering drugs through the intestinal mucosa and blood-brain barriers (BBB). The goal here is to describe the general structures of the biological barriers and the strategies to enhance drug delivery across these barriers. Prodrug methods used to improve drug penetration via the transcellular pathway have been successfully developed, and some prodrugs have been used to treat patients. The use of transporters to improve absorption of some drugs (e.g., antiviral agents) has also been successful in treating patients. Other methods, including (a) blocking the efflux pumps to improve transcellular delivery and (b) modulation of cell-cell adhesion in the intercellular junctions to improve paracellular delivery across biological barriers are still in the investigational stage. PMID:25418271

  19. Capture, crawl, cross: the T cell code to breach the blood-brain barriers.

    PubMed

    Engelhardt, Britta; Ransohoff, Richard M

    2012-12-01

    The central nervous system (CNS) is an immunologically privileged site to which access of circulating immune cells is tightly controlled by the endothelial blood-brain barrier (BBB; see Glossary) localized in CNS microvessels, and the epithelial blood-cerebrospinal fluid barrier (BCSFB) within the choroid plexus. As a result of the specialized structure of the CNS barriers, immune cell entry into the CNS parenchyma involves two differently regulated steps: migration of immune cells across the BBB or BCSFB into the cerebrospinal fluid (CSF)-drained spaces of the CNS, followed by progression across the glia limitans into the CNS parenchyma. With a focus on multiple sclerosis (MS) and its animal models, this review summarizes the distinct molecular mechanisms required for immune cell migration across the different CNS barriers. PMID:22926201

  20. Memantine ameliorates autistic behavior, biochemistry & blood brain barrier impairments in rats.

    PubMed

    Kumar, Hariom; Sharma, Bhupesh

    2016-06-01

    Autism spectrum disorder (ASD) is a neurodevelopmental disorder, commonly characterized by altered social behavior, communication, biochemistry and pathological conditions. One percent of the worldwide population suffers from autism and males suffer more than females. NMDA receptors have the important role in neurodevelopment, neuropsychiatric and neurodegenerative disorders. This study has been designed to investigate the role of memantine, a NMDA receptor modulator, in prenatal valproic acid-induced autism in rats. Animals with prenatal valproic acid have shown the reduction in social interaction (three-chamber social behavior apparatus), spontaneous alternation (Y-Maze), exploratory activity (Hole board test), intestinal motility, serotonin levels (both in prefrontal cortex and ileum) and prefrontal cortex mitochondrial complex activity (complex I, II, IV). Furthermore, prenatal valproic acid-treated animals have shown an increase in locomotion (actophotometer), anxiety (elevated plus maze), brain oxidative stress (thiobarbituric acid reactive species, glutathione, catalase), nitrosative stress (nitrite/nitrate), inflammation (both in brain and ileum myeloperoxidase activity), calcium and blood-brain barrier permeability. Treatment with memantine has significantly attenuated prenatal valproic acid-induced reduction in social interaction, spontaneous alteration, exploratory activity intestinal motility, serotonin levels and prefrontal cortex mitochondrial complex activity. Furthermore, memantine has also attenuated the prenatal valproic acid-induced increase in locomotion, anxiety, brain oxidative and nitrosative stress, inflammation, calcium and blood-brain barrier permeability. Thus, it may be concluded that prenatal valproic acid has induced autistic behavior, biochemistry and blood-brain barrier impairment in animals, which were significantly attenuated by memantine. NMDA receptor modulators like memantine should be explored further for the therapeutic

  1. Restraint Stress-Induced Morphological Changes at the Blood-Brain Barrier in Adult Rats

    PubMed Central

    Sántha, Petra; Veszelka, Szilvia; Hoyk, Zsófia; Mészáros, Mária; Walter, Fruzsina R.; Tóth, Andrea E.; Kiss, Lóránd; Kincses, András; Oláh, Zita; Seprényi, György; Rákhely, Gábor; Dér, András; Pákáski, Magdolna; Kálmán, János; Kittel, Ágnes; Deli, Mária A.

    2016-01-01

    Stress is well-known to contribute to the development of both neurological and psychiatric diseases. While the role of the blood-brain barrier is increasingly recognized in the development of neurodegenerative disorders, such as Alzheimer's disease, dysfunction of the blood-brain barrier has been linked to stress-related psychiatric diseases only recently. In the present study the effects of restraint stress with different duration (1, 3, and 21 days) were investigated on the morphology of the blood-brain barrier in male adult Wistar rats. Frontal cortex and hippocampus sections were immunostained for markers of brain endothelial cells (claudin-5, occluding, and glucose transporter-1) and astroglia (GFAP). Staining pattern and intensity were visualized by confocal microscopy and evaluated by several types of image analysis. The ultrastructure of brain capillaries was investigated by electron microscopy. Morphological changes and intensity alterations in brain endothelial tight junction proteins claudin-5 and occludin were induced by stress. Following restraint stress significant increases in the fluorescence intensity of glucose transporter-1 were detected in brain endothelial cells in the frontal cortex and hippocampus. Significant reductions in GFAP fluorescence intensity were observed in the frontal cortex in all stress groups. As observed by electron microscopy, 1-day acute stress induced morphological changes indicating damage in capillary endothelial cells in both brain regions. After 21 days of stress thicker and irregular capillary basal membranes in the hippocampus and edema in astrocytes in both regions were seen. These findings indicate that stress exerts time-dependent changes in the staining pattern of tight junction proteins occludin, claudin-5, and glucose transporter-1 at the level of brain capillaries and in the ultrastructure of brain endothelial cells and astroglial endfeet, which may contribute to neurodegenerative processes, cognitive and

  2. Radiographic quantitation of reversible blood-brain barrier disruption in vivo. [Dogs

    SciTech Connect

    Drayer, B.P.; Schmeckel, D.E.; Hedlund, L.W.; Lischko, M.M.; Sage, M.R.; Heinz, E.R.; Dubois, P.J.; Goulding, P.L.

    1982-04-01

    Cranial computed tomography (CT) was used to quantitate disruption of the blood-brain barrier (BBB) in dogs in vivo following intracarotid infusion of hypertonic mannitol. The degree of opening varied with the same dose and infusion rate. The ratio of contrast enhancement in brain vs. venous blood was elevated in 4 of 5 mannitol-treated animals, with the ipsilateral basal ganglia and cortical gray matter. The statistical significance and reproducibility of the derived CT numbers used for brain and venous blood calculations, as well as the linear relationship between iodine concentration and CT enhancement, was affirmed by obtaining multiple consecutive scans.

  3. Mechanisms of restriction of viral neuroinvasion at the blood-brain barrier.

    PubMed

    Miner, Jonathan J; Diamond, Michael S

    2016-02-01

    The blood-brain barrier (BBB) consists of highly specialized cells including brain microvascular endothelial cells, astrocytes, microglia, pericytes, and neurons, which act in concert to restrict the entry of pathogens, immune cells, and soluble molecules into the central nervous system (CNS). If pathogens manage to cross the BBB and establish infection within the CNS, the BBB can open in a regulated manner to allow leukocyte transmigration into the CNS so that microbes, infected cells, and debris can be cleared. This review highlights how different inflammatory cytokines or signaling pathways disrupt or enhance BBB integrity in a way that regulates entry of neurotropic viruses into the CNS. PMID:26590675

  4. Blood-brain barrier shuttle peptides: an emerging paradigm for brain delivery.

    PubMed

    Oller-Salvia, Benjamí; Sánchez-Navarro, Macarena; Giralt, Ernest; Teixidó, Meritxell

    2016-08-22

    Brain delivery is one of the major challenges in drug development because of the high number of patients suffering from neural diseases and the low efficiency of the treatments available. Although the blood-brain barrier (BBB) prevents most drugs from reaching their targets, molecular vectors - known as BBB shuttles - offer great promise to safely overcome this formidable obstacle. In recent years, peptide shuttles have received growing attention because of their lower cost, reduced immunogenicity, and higher chemical versatility than traditional Trojan horse antibodies and other proteins. PMID:27188322

  5. Role of histaminergic system in blood-brain barrier dysfunction associated with neurological disorders.

    PubMed

    Bañuelos-Cabrera, Ivette; Valle-Dorado, María Guadalupe; Aldana, Blanca Irene; Orozco-Suárez, Sandra Adela; Rocha, Luisa

    2014-11-01

    Blood-brain barrier (BBB) disruption has been associated with several acute and chronic brain disorders such as Alzheimer's disease, Parkinson's disease and epilepsy. This represents a critical situation because damaged integrity of the BBB is related to the influx of immune mediators, plasma proteins and other outside elements from blood to the central nervous system (CNS) that may trigger a cascade of events that leads to neuroinflammation. In this review, evidence that mast cells and the release of factors such as histamine play an important role in the neuroinflammatory process associated with brain disorders such as Alzheimer's disease, Parkinson's disease and epilepsy is presented. PMID:25446620

  6. Targeted delivery of protein and gene medicines through the blood-brain barrier.

    PubMed

    Pardridge, W M

    2015-04-01

    The development of biologic drugs (recombinant proteins, therapeutic antibodies, peptides, nucleic acid therapeutics) as new treatments of brain disorders has been difficult, and a major reason is the lack of transport through the blood-brain barrier (BBB) of these large molecule pharmaceuticals. Biologic drugs can be re-engineered as brain-penetrating neuropharmaceuticals using BBB molecular Trojan horse technology. Certain peptidomimetic monoclonal antibodies that target endogenous receptors on the BBB, such as the insulin or transferrin receptor, enable the re-engineering of biologic drugs that cross the BBB. PMID:25669455

  7. Chronic systemic IL-1β exacerbates central neuroinflammation independently of the blood-brain barrier integrity.

    PubMed

    Murta, Verónica; Farías, María Isabel; Pitossi, Fernando Juan; Ferrari, Carina Cintia

    2015-01-15

    Peripheral circulating cytokines are involved in immune to brain communication and systemic inflammation is considered a risk factor for flaring up the symptoms in most neurodegenerative diseases. We induced both central inflammatory demyelinating lesion, and systemic inflammation with an interleukin-1β expressing adenovector. The peripheral pro-inflammatory stimulus aggravated the ongoing central lesion independently of the blood-brain barrier (BBB) integrity. This model allows studying the role of specific molecules and cells (neutrophils) from the innate immune system, in the relationship between central and peripheral communication, and on relapsing episodes of demyelinating lesions, along with the role of BBB integrity. PMID:25595250

  8. Viral interactions with the blood-brain barrier: old dog, new tricks.

    PubMed

    Hou, Jianghui; Baker, Lane A; Zhou, Lushan; Klein, Robyn S

    2016-01-01

    Brain endothelial cells form a unique cellular structure known as the tight junction to regulate the exchanges between the blood and the parenchyma by limiting the paracellular diffusion of blood-borne substance. Together with the restricted pathway of transcytosis, the tight junction in the brain endothelial cells provides the central nervous system (CNS) with effective protection against both the foreign pathogens and the host immune cells, which is also termed the "blood-brain barrier." The blood-brain barrier is particularly important for defending against neurotropic viral infections that have become a major source of diseases worldwide. Many neurotropic viruses are able to cross the BBB and infect the CNS through very poorly understood processes. This review focuses upon the structural and functional changes of the brain endothelial tight junction in response to viral infections in the CNS and how the tight junction changes may be studied with advanced imaging and recording approaches to reveal novel processes used by the viruses to cross the barrier system. Additional emphasis is placed upon new countermeasures that can act directly upon the tight junction to improve the pathogen clearance and minimize the inflammatory damage. PMID:27141421

  9. An ex Vivo Model for Evaluating Blood-Brain Barrier Permeability, Efflux, and Drug Metabolism.

    PubMed

    Hellman, Karin; Aadal Nielsen, Peter; Ek, Fredrik; Olsson, Roger

    2016-05-18

    The metabolism of drugs in the brain is difficult to study in most species because of enzymatic instability in vitro and interference from peripheral metabolism in vivo. A locust ex vivo model that combines brain barrier penetration, efflux, metabolism, and analysis of the unbound fraction in intact brains was evaluated using known drugs. Clozapine was analyzed, and its major metabolites, clozapine N-oxide (CNO) and N-desmethylclozapine (NDMC), were identified and quantified. The back-transformation of CNO into clozapine observed in humans was also observed in locusts. In addition, risperidone, citalopram, fluoxetine, and haloperidol were studied, and one preselected metabolite for each drug was analyzed, identified, and quantified. Metabolite identification studies of clozapine and midazolam showed that the locust brain was highly metabolically active, and 18 and 14 metabolites, respectively, were identified. The unbound drug fraction of clozapine, NDMC, carbamazepine, and risperidone was analyzed. In addition, coadministration of drugs with verapamil or fluvoxamine was performed to evaluate drug-drug interactions in all setups. All findings correlated well with the data in the literature for mammals except for the stated fact that CNO is a highly blood-brain barrier permeant compound. Overall, the experiments indicated that invertebrates might be useful for screening of blood-brain barrier permeation, efflux, metabolism, and analysis of the unbound fraction of drugs in the brain in early drug discovery. PMID:26930271

  10. Measurement of blood-brain barrier permeability with positron emission tomography and (68Ga)EDTA

    SciTech Connect

    Kessler, R.M.; Goble, J.C.; Bird, J.H.; Girton, M.E.; Doppman, J.L.; Rapoport, S.I.; Barranger, J.A.

    1984-09-01

    Positron emission tomography (PET) was employed to examine time-dependent changes in blood-brain barrier (BBB) permeability to (68Ga)ethylenediaminetetraacetate (EDTA) in the rhesus monkey, following reversible barrier opening by intracarotid infusion of a hypertonic mannitol solution. The PET technique, when combined with measurements of plasma radioactivity, provided a quantitative measure of the cerebrovascular permeability-area product (PA) at different times following mannitol infusion. Hypertonic mannitol treatment reversibly increased PA to (68Ga)EDTA more than 10-fold; much of the barrier effect was over by 10 min after mannitol treatment. The results show that PET can be used to measure transient changes in BBB integrity in specific brain regions, under in vivo, noninvasive conditions.

  11. PARAQUAT IS EXCLUDED BY THE BLOOD BRAIN BARRIER IN RHESUS MACAQUE: AN IN VIVO PET STUDY

    PubMed Central

    Bartlett, Rachel M.; Holden, James E.; Nickles, R. Jerome; Murali, Dhanabalan; Barbee, David L.; Barnhart, Todd E.; Christian, Bradley C.; DeJesus, Onofre T.

    2009-01-01

    Environmental factors have long been thought to have a role in the etiology of idiopathic Parkinson’s Disease (PD). Since the discovery of the selective neurotoxicity of MPTP to dopamine cells, suspicion has focused on paraquat, a common herbicide with chemical structure similar to 1-methyl-4-phenylpyridinium (MPP+), the MPTP metabolite responsible for its neurotoxicity. Although in vitro evidence for paraquat neurotoxicity to dopamine cells is well established, its in vivo effects have been ambiguous because paraquat is di-cationic in plasma, which raises questions about its ability to cross the blood brain barrier. This study assessed the brain uptake of [11C]-paraquat in adult male rhesus macaques using quantitative PET imaging. Results showed minimal uptake of [11C]-paraquat in the macaque brain. The highest concentrations of paraquat was seen in the pineal gland and the lateral ventricles. Global brain concentrations including those in known dopamine areas were consistent with the blood volume in those structures. This acute exposure study found that paraquat is excluded from the brain by the blood brain barrier and thus does not readily support the causative role of paraquat exposure in idiopathic Parkinson’s Disease. PMID:19135428

  12. Differential effect of aluminum on the blood-brain barrier transport of peptides, technetium and albumin

    SciTech Connect

    Banks, W.A.; Kastin, A.J.; Fasold, M.B.

    1988-02-01

    Aluminum is a neurotoxin capable of altering membrane structure and function. We investigated whether aluminum also can affect saturable transport across membranes using the blood-brain barrier as our model. Mice were given i.p. or i.v. aluminum (up to 100 mg/kg) as the chloride salt and the disappearance from the brain of several centrally administered substances was measured. We found that aluminum rapidly and profoundly inhibited the saturable system that transports the small, N-tyrosinated peptides Tyr-MIF-1 and the enkephalins from the brain to the blood by acting as a noncompetitive inhibitor. In contrast, the disappearance from the brain of technetium pertechnetate (a substance also transported out of the brain by a different saturable system), albumin or D-Tyr-MIF-1 (a stereoisomer of Tyr-MIF-1 that was confirmed not to be transported by the carrier system) was not affected by aluminum. Aluminum also did not alter either the saturable or nonsaturable component of the uptake of Tyr-MIF-1 by erythrocytes. These findings suggest that one mechanism by which aluminum may induce neurotoxicity is by selective alteration of the transport systems of the blood-brain barrier.

  13. Cerebral circulation, metabolism, and blood-brain barrier of rats in hypocapnic hypoxia

    SciTech Connect

    Beck, T.; Krieglstein, J.

    1987-03-01

    The effects of hypoxic hypoxia on physiological variables, cerebral circulation, cerebral metabolism, and blood-brain barrier were investigated in conscious, spontaneously breathing rats by exposing them to an atmosphere containing 7% O/sub 2/. Hypoxia affected a marked hypotension, hypocapnia and alkalosis. Cortical tissue high-energy phosphates and glucose content were not affected by hypoxia, glucose 6-phosphate lactate, and pyruvate levels were significantly increased. Blood-brain barrier permeability, regional brain glucose content and lumped constant were not changed by hypoxia. Local cerebral glucose utilization (LCGU) rose by 40-70% of control values in gray matter and by 80-90% in white matter. Under hypoxia, columns of increased and decreased LCGU and were detectable in cortical gray matter. Color-coded (/sup 14/C)2-deoxy-D-glucose autoradiograms of rat brain are shown. Local cerebral blood flow (LCBF) increased by 50-90% in gray matter and by up to 180% in white matter. Coupling between LCGU and LCBF in hypoxia remained unchanged. The data suggests a stimulation of glycolysis, increased glucose transport into the cell, and increased hexokinase activity. The physiological response of gray and white matter to hypoxia obviously differs. Uncoupling of the relation between LCGU and LCBF does not occur.

  14. Interaction of ethanol and microwaves on the blood-brain barrier of rats

    SciTech Connect

    Neilly, J.P.; Lin, J.C.

    1986-01-01

    The combined effects of ethanol and microwaves on the permeation of Evans blue dye through the mammalian blood-brain barrier was studied in male Wistar rats. Anesthetized rats were infused through a cannula in the left femoral vein with 0.1, 0.3, 0.5 or 0.7 grams of absolute ethanol per kilogram of body mass. A control group was given 0.7 g/kg of isotonic saline. The left hemisphere of the brain was irradiated by 3.15-GHz microwave energy at 3.0 W/cm2 rms for 15 min. The rat's rectal temperature was maintained at 37.0 degrees C. Immediately after irradiation, 2% Evans blue dye in saline (2.0 ml/kg body mass) was injected through the cannula. The results show that as the quantity of alcohol was increased, the degree of staining was decreased or eliminated. The temperature of the irradiated area of the brain increased for the first 4 to 5 minutes of irradiation and then stabilized for the remainder of the irradiation period. The steady-state temperature was highest in animals receiving saline or the smallest dose of alcohol. As the quantity of alcohol was increased, the steady-state temperature was reduced. These results indicate that ethanol inhibits microwave-induced permeation of the blood-brain barrier through reduced heating of the brain.

  15. Blood-brain barrier changes with kainic acid-induced limbic seizures

    SciTech Connect

    Zucker, D.K.; Wooten, G.F.; Lothman, E.W.

    1983-02-01

    Rats were treated with kainic acid (KA) i.v. to produce increasingly severe limbic seizures that were monitored with a behavioral rating scale. At various times after the induction of seizures, the animals; blood-brain barriers (B-BB) were studied with alpha-(/sup 14/C)aminoisobutyric acid ((/sup 14/C)AIBA) autoradiography. Using optical density ratios, a coefficient was devised to assess the functional integrity of the B-BB in discrete anatomic regions and to quantitatively compare these measurements among different groups of experimental animals. In animals that exhibited only mild seizures, the B-BB was not different from controls. Animals with severe limbic seizures, however, showed alterations. For as long as 2 h after delivery of KA, the B-BB appeared normal; from 2 to 24 h, the permeability to (/sup 14/C)AIBA was markedly increased throughout the brain, especially in limbic regions; from 24 h to 7 days the B-BB returned to normal except for a small residual change in limbic structures. These findings were confirmed with Evans blue dye studies of the B-BB. A correlation between focal accentuation of B-BB alterations and neuropathologic changes was found. These experiments indicted that recurrent limbic seizures may lead to a breakdown in the B-BB independent of systemic metabolic derangements. Marked focal metabolic and electrical changes, however, occurred in several limbic structures several hours before the blood-brain barrier was altered.

  16. Agent based modeling of the effects of potential treatments over the blood-brain barrier in multiple sclerosis.

    PubMed

    Pennisi, Marzio; Russo, Giulia; Motta, Santo; Pappalardo, Francesco

    2015-12-01

    Multiple sclerosis is a disease of the central nervous system that involves the destruction of the insulating sheath of axons, causing severe disabilities. Since the etiology of the disease is not yet fully understood, the use of novel techniques that may help to understand the disease, to suggest potential therapies and to test the effects of candidate treatments is highly advisable. To this end we developed an agent based model that demonstrated its ability to reproduce the typical oscillatory behavior observed in the most common form of multiple sclerosis, relapsing-remitting multiple sclerosis. The model has then been used to test the potential beneficial effects of vitamin D over the disease. Many scientific studies underlined the importance of the blood-brain barrier and of the mechanisms that influence its permeability on the development of the disease. In the present paper we further extend our previously developed model with a mechanism that mimics the blood-brain barrier behavior. The goal of our work is to suggest the best strategies to follow for developing new potential treatments that intervene in the blood-brain barrier. Results suggest that the best treatments should potentially prevent the opening of the blood-brain barrier, as treatments that help in recovering the blood-brain barrier functionality could be less effective. PMID:26343337

  17. Altered blood-brain barrier permeability in rats with prehepatic portal hypertension turns to normal when portal pressure is lowered

    PubMed Central

    Eizayaga, Francisco; Scorticati, Camila; Prestifilippo, Juan P; Romay, Salvador; Fernandez, Maria A; Castro, José L; Lemberg, Abraham; Perazzo, Juan C

    2006-01-01

    AIM: To study the blood-brain barrier integrity in prehepatic portal hypertensive rats induced by partial portal vein ligation, at 14 and 40 d after ligation when portal pressure is spontaneously normalized. METHODS: Adult male Wistar rats were divided into four groups: Group I: Sham14d , sham operated; Group II: PH14d , portal vein stenosis; (both groups were used 14 days after surgery); Group III: Sham40d, Sham operated and Group IV: PH40d Portal vein stenosis (Groups II and IV used 40 d after surgery). Plasma ammonia, plasma and cerebrospinal fluid protein and liver enzymes concentrations were determined. Trypan and Evans blue dyes, systemically injected, were investigated in hippocampus to study blood-brain barrier integrity. Portal pressure was periodically recorded. RESULTS: Forty days after stricture, portal pressure was normalized, plasma ammonia was moderately high, and both dyes were absent in central nervous system parenchyma. All other parameters were reestablished. When portal pressure was normalized and ammonia level was lowered, but not normal, the altered integrity of blood-brain barrier becomes reestablished. CONCLUSION: The impairment of blood-brain barrier and subsequent normalization could be a mechanism involved in hepatic encephalopathy reversibility. Hemodynamic changes and ammonia could trigger blood-brain barrier alterations and its reestablishment. PMID:16552803

  18. Non-viral liposome-mediated transfer of brain-derived neurotrophic factor across the blood-brain barrier

    PubMed Central

    Xing, Ying; Wen, Chun-yan; Li, Song-tao; Xia, Zong-xin

    2016-01-01

    Brain-derived neurotrophic factor (BDNF) plays an important role in the repair of central nervous system injury, but cannot directly traverse the blood-brain barrier. Liposomes are a new type of non-viral vector, able to carry macromolecules across the blood-brain barrier and into the brain. Here, we investigate whether BDNF could be transported across the blood-brain barrier by tail-vein injection of liposomes conjugated to transferrin (Tf) and polyethylene glycol (PEG), and carrying BDNF modified with cytomegalovirus promoter (pCMV) or glial fibrillary acidic protein promoter (pGFAP) (Tf-pCMV-BDNF-PEG and Tf-pGFAP-BDNF-PEG, respectively). Both liposomes were able to traverse the blood-brain barrier, and BDNF was mainly expressed in the cerebral cortex. BDNF expression in the cerebral cortex was higher in the Tf-pGFAP-BDNF-PEG group than in the Tf-pCMV-BDNF-PEG group. This study demonstrates the successful construction of a non-virus targeted liposome, Tf-pGFAP-BDNF-PEG, which crosses the blood-brain barrier and is distributed in the cerebral cortex. Our work provides an experimental basis for BDNF-related targeted drug delivery in the brain. PMID:27212923

  19. Non-viral liposome-mediated transfer of brain-derived neurotrophic factor across the blood-brain barrier.

    PubMed

    Xing, Ying; Wen, Chun-Yan; Li, Song-Tao; Xia, Zong-Xin

    2016-04-01

    Brain-derived neurotrophic factor (BDNF) plays an important role in the repair of central nervous system injury, but cannot directly traverse the blood-brain barrier. Liposomes are a new type of non-viral vector, able to carry macromolecules across the blood-brain barrier and into the brain. Here, we investigate whether BDNF could be transported across the blood-brain barrier by tail-vein injection of liposomes conjugated to transferrin (Tf) and polyethylene glycol (PEG), and carrying BDNF modified with cytomegalovirus promoter (pCMV) or glial fibrillary acidic protein promoter (pGFAP) (Tf-pCMV-BDNF-PEG and Tf-pGFAP-BDNF-PEG, respectively). Both liposomes were able to traverse the blood-brain barrier, and BDNF was mainly expressed in the cerebral cortex. BDNF expression in the cerebral cortex was higher in the Tf-pGFAP-BDNF-PEG group than in the Tf-pCMV-BDNF-PEG group. This study demonstrates the successful construction of a non-virus targeted liposome, Tf-pGFAP-BDNF-PEG, which crosses the blood-brain barrier and is distributed in the cerebral cortex. Our work provides an experimental basis for BDNF-related targeted drug delivery in the brain. PMID:27212923

  20. An Unexpected Transient Breakdown of the Blood Brain Barrier Triggers Passage of Large Intravenously Administered Nanoparticles

    PubMed Central

    Smith, Nicole M.; Gachulincova, Ivana; Ho, Diwei; Bailey, Charlotte; Bartlett, Carole A.; Norret, Marck; Murphy, John; Buckley, Alysia; Rigby, Paul J.; House, Michael J.; St. Pierre, Timothy; Fitzgerald, Melinda; Iyer, K. Swaminathan; Dunlop, Sarah A.

    2016-01-01

    The highly restrictive blood-brain barrier (BBB) plays a critically important role in maintaining brain homeostasis and is pivotal for proper neuronal function. The BBB is currently considered the main limiting factor restricting the passage of large (up to 200 nm) intravenously administered nanoparticles to the brain. Breakdown of the barrier occurs as a consequence of cerebrovascular diseases and traumatic brain injury. In this article, we report that remote injuries in the CNS are also associated with BBB dysfunction. In particular, we show that a focal partial transection of the optic nerve triggers a previously unknown transient opening of the mammalian BBB that occurs in the visual centres. Importantly, we demonstrate that this transient BBB breakdown results in a dramatic change in the biodistribution of intravenously administered large polymeric nanoparticles which were previously deemed as BBB-impermeable. PMID:26940762

  1. Implications of MMP9 for Blood Brain Barrier Disruption and Hemorrhagic Transformation Following Ischemic Stroke

    PubMed Central

    Turner, Renée J.; Sharp, Frank R.

    2016-01-01

    Numerous studies have documented increases in matrix metalloproteinases (MMPs), specifically MMP-9 levels following stroke, with such perturbations associated with disruption of the blood brain barrier (BBB), increased risk of hemorrhagic complications, and worsened outcome. Despite this, controversy remains as to which cells release MMP-9 at the normal and pathological BBB, with even less clarity in the context of stroke. This may be further complicated by the influence of tissue plasminogen activator (tPA) treatment. The aim of the present review is to examine the relationship between neutrophils, MMP-9 and tPA following ischemic stroke to elucidate which cells are responsible for the increases in MMP-9 and resultant barrier changes and hemorrhage observed following stroke. PMID:26973468

  2. An Unexpected Transient Breakdown of the Blood Brain Barrier Triggers Passage of Large Intravenously Administered Nanoparticles

    NASA Astrophysics Data System (ADS)

    Smith, Nicole M.; Gachulincova, Ivana; Ho, Diwei; Bailey, Charlotte; Bartlett, Carole A.; Norret, Marck; Murphy, John; Buckley, Alysia; Rigby, Paul J.; House, Michael J.; St. Pierre, Timothy; Fitzgerald, Melinda; Iyer, K. Swaminathan; Dunlop, Sarah A.

    2016-03-01

    The highly restrictive blood-brain barrier (BBB) plays a critically important role in maintaining brain homeostasis and is pivotal for proper neuronal function. The BBB is currently considered the main limiting factor restricting the passage of large (up to 200 nm) intravenously administered nanoparticles to the brain. Breakdown of the barrier occurs as a consequence of cerebrovascular diseases and traumatic brain injury. In this article, we report that remote injuries in the CNS are also associated with BBB dysfunction. In particular, we show that a focal partial transection of the optic nerve triggers a previously unknown transient opening of the mammalian BBB that occurs in the visual centres. Importantly, we demonstrate that this transient BBB breakdown results in a dramatic change in the biodistribution of intravenously administered large polymeric nanoparticles which were previously deemed as BBB-impermeable.

  3. The gut microbiota influences blood-brain barrier permeability in mice.

    PubMed

    Braniste, Viorica; Al-Asmakh, Maha; Kowal, Czeslawa; Anuar, Farhana; Abbaspour, Afrouz; Tóth, Miklós; Korecka, Agata; Bakocevic, Nadja; Ng, Lai Guan; Guan, Ng Lai; Kundu, Parag; Gulyás, Balázs; Halldin, Christer; Hultenby, Kjell; Nilsson, Harriet; Hebert, Hans; Volpe, Bruce T; Diamond, Betty; Pettersson, Sven

    2014-11-19

    Pivotal to brain development and function is an intact blood-brain barrier (BBB), which acts as a gatekeeper to control the passage and exchange of molecules and nutrients between the circulatory system and the brain parenchyma. The BBB also ensures homeostasis of the central nervous system (CNS). We report that germ-free mice, beginning with intrauterine life, displayed increased BBB permeability compared to pathogen-free mice with a normal gut flora. The increased BBB permeability was maintained in germ-free mice after birth and during adulthood and was associated with reduced expression of the tight junction proteins occludin and claudin-5, which are known to regulate barrier function in endothelial tissues. Exposure of germ-free adult mice to a pathogen-free gut microbiota decreased BBB permeability and up-regulated the expression of tight junction proteins. Our results suggest that gut microbiota-BBB communication is initiated during gestation and propagated throughout life. PMID:25411471

  4. Chromatographic behaviour predicts the ability of potential nootropics to permeate the blood-brain barrier.

    PubMed

    Farsa, Oldřich

    2013-03-01

    The log BB parameter is the logarithm of the ratio of a compound's equilibrium concentrations in the brain tissue versus the blood plasma. This parameter is a useful descriptor in assessing the ability of a compound to permeate the blood-brain barrier. The aim of this study was to develop a Hansch-type linear regression QSAR model that correlates the parameter log BB and the retention time of drugs and other organic compounds on a reversed-phase HPLC containing an embedded amide moiety. The retention time was expressed by the capacity factor log k'. The second aim was to estimate the brain's absorption of 2-(azacycloalkyl)acetamidophenoxyacetic acids, which are analogues of piracetam, nefiracetam, and meclofenoxate. Notably, these acids may be novel nootropics. Two simple regression models that relate log BB and log k' were developed from an assay performed using a reversed-phase HPLC that contained an embedded amide moiety. Both the quadratic and linear models yielded statistical parameters comparable to previously published models of log BB dependence on various structural characteristics. The models predict that four members of the substituted phenoxyacetic acid series have a strong chance of permeating the barrier and being absorbed in the brain. The results of this study show that a reversed-phase HPLC system containing an embedded amide moiety is a functional in vitro surrogate of the blood-brain barrier. These results suggest that racetam-type nootropic drugs containing a carboxylic moiety could be more poorly absorbed than analogues devoid of the carboxyl group, especially if the compounds penetrate the barrier by a simple diffusion mechanism. PMID:23641330

  5. Chromatographic Behaviour Predicts the Ability of Potential Nootropics to Permeate the Blood-Brain Barrier

    PubMed Central

    Farsa, Oldřich

    2013-01-01

    The log BB parameter is the logarithm of the ratio of a compound’s equilibrium concentrations in the brain tissue versus the blood plasma. This parameter is a useful descriptor in assessing the ability of a compound to permeate the blood-brain barrier. The aim of this study was to develop a Hansch-type linear regression QSAR model that correlates the parameter log BB and the retention time of drugs and other organic compounds on a reversed-phase HPLC containing an embedded amide moiety. The retention time was expressed by the capacity factor log k′. The second aim was to estimate the brain’s absorption of 2-(azacycloalkyl)acetamidophenoxyacetic acids, which are analogues of piracetam, nefiracetam, and meclofenoxate. Notably, these acids may be novel nootropics. Two simple regression models that relate log BB and log k′ were developed from an assay performed using a reversed-phase HPLC that contained an embedded amide moiety. Both the quadratic and linear models yielded statistical parameters comparable to previously published models of log BB dependence on various structural characteristics. The models predict that four members of the substituted phenoxyacetic acid series have a strong chance of permeating the barrier and being absorbed in the brain. The results of this study show that a reversed-phase HPLC system containing an embedded amide moiety is a functional in vitro surrogate of the blood-brain barrier. These results suggest that racetam-type nootropic drugs containing a carboxylic moiety could be more poorly absorbed than analogues devoid of the carboxyl group, especially if the compounds penetrate the barrier by a simple diffusion mechanism. PMID:23641330

  6. Focused ultrasound induced blood-brain barrier disruption to enhance chemotherapeutic drugs (BCNU) delivery for glioblastoma treatment

    NASA Astrophysics Data System (ADS)

    Liu, Hao-Li; Hua, Mu-Yi; Chen, Pin-Yuan; Huang, Chiung-Yin; Wang, Jiun-Jie; Wei, Kuo-Chen

    2010-03-01

    Focused ultrasound has been recently found to capable of temporally and reversibly disrupt local blood-brain barrier (BBB) and opens new frontier in delivering varies type of drugs into brain for central nerve system (CNS) disorder treatment. In this study, we aim to investigate the feasibility of delivering 1, 3-bits (2-chloroethyl) -1-nitrosourea (BCNU) to treat glioblastoma in animal models and evaluate whether this approach would gain treatment efficacy. Under the presence of microbubbles administration, a 400-kHz focused ultrasound was employed to deliver burst-tone ultrasonic energy stimulation to disrupt BBB in animal brains transcranially, and in-vivo monitored by magnetic-resonance imaging (MRI). C6-glioma cells were cultured and implanted into Sprague-Dawley rats as the brain-tumor model. BCNU deposited in brain was quantified by using high-performance liquid chromatography (HPLC), and brain tissues were examined histologically. MRI was employed to longitudinal evaluate the brain tumor treatment including the analysis of tumor progression and animal survival. We confirmed that the focused ultrasound, under the secure ultrasonic energy level, can significantly enhance the BCNU penetration through BBB over 300% than control without cause hemorrhage. Apparent improvement of treatment efficacy achieved by combining focused ultrasound with BCNU delivery, including significant suppression of tumor growth and a prolonged animal survival. This study highly support that this treatment strategy could be clinically-relevant and may help to provide another potential strategy in increasing local chemotherapeutic drugs for brain-tumor treatment.

  7. Gap Junction Proteins in the Blood-Brain Barrier Control Nutrient-Dependent Reactivation of Drosophila Neural Stem Cells

    PubMed Central

    Spéder, Pauline; Brand, Andrea H.

    2014-01-01

    Summary Neural stem cells in the adult brain exist primarily in a quiescent state but are reactivated in response to changing physiological conditions. How do stem cells sense and respond to metabolic changes? In the Drosophila CNS, quiescent neural stem cells are reactivated synchronously in response to a nutritional stimulus. Feeding triggers insulin production by blood-brain barrier glial cells, activating the insulin/insulin-like growth factor pathway in underlying neural stem cells and stimulating their growth and proliferation. Here we show that gap junctions in the blood-brain barrier glia mediate the influence of metabolic changes on stem cell behavior, enabling glia to respond to nutritional signals and reactivate quiescent stem cells. We propose that gap junctions in the blood-brain barrier are required to translate metabolic signals into synchronized calcium pulses and insulin secretion. PMID:25065772

  8. Adult human dental pulp stem cells promote blood-brain barrier permeability through vascular endothelial growth factor-a expression.

    PubMed

    Winderlich, Joshua N; Kremer, Karlea L; Koblar, Simon A

    2016-06-01

    Stem cell therapy is a promising new treatment option for stroke. Intravascular administration of stem cells is a valid approach as stem cells have been shown to transmigrate the blood-brain barrier. The mechanism that causes this effect has not yet been elucidated. We hypothesized that stem cells would mediate localized discontinuities in the blood-brain barrier, which would allow passage into the brain parenchyma. Here, we demonstrate that adult human dental pulp stem cells express a soluble factor that increases permeability across an in vitro model of the blood-brain barrier. This effect was shown to be the result of vascular endothelial growth factor-a. The effect could be amplified by exposing dental pulp stem cell to stromal-derived factor 1, which stimulates vascular endothelial growth factor-a expression. These findings support the use of dental pulp stem cell in therapy for stroke. PMID:26661186

  9. Noninvasive localized delivery of Herceptin to the mouse brain by MRI-guided focused ultrasound-induced blood-brain barrier disruption

    NASA Astrophysics Data System (ADS)

    Kinoshita, Manabu; McDannold, Nathan; Jolesz, Ferenc A.; Hynynen, Kullervo

    2006-08-01

    Antibody-based anticancer agents are promising chemotherapeutic agents. Among these agents, Herceptin (trastuzumab), a humanized anti-human epidermal growth factor receptor 2 (HER2/c-erbB2) monoclonal antibody, has been used successfully in patients with breast cancer. However, in patients with brain metastasis, the blood-brain barrier limits its use, and a different delivery method is needed to treat these patients. Here, we report that Herceptin can be delivered locally and noninvasively into the mouse central nervous system through the blood-brain barrier under image guidance by using an MRI-guided focused ultrasound blood-brain barrier disruption technique. The amount of Herceptin delivered to the target tissue was correlated with the extent of the MRI-monitored barrier opening, making it possible to estimate indirectly the amount of Herceptin delivered. Histological changes attributable to this procedure were minimal. This method may represent a powerful technique for the delivery of macromolecular agents such as antibodies to treat patients with diseases of the central nervous system. brain tumor | microbubble

  10. Blood-brain barrier properties in vitro depend on composition and assembly of endogenous extracellular matrices.

    PubMed

    Zobel, Kathrin; Hansen, Uwe; Galla, Hans-Joachim

    2016-08-01

    Brain capillary endothelial cells, which constitute the blood-brain barrier (BBB), are enveloped by the extracellular matrix (ECM) produced by endothelial cells, pericytes and astrocytes. The contribution of matrix components secreted by the various cell types at the neurovascular unit, however, remains unclear with respect to their effect on endothelial barrier function. In this study, a new in vitro model was established by growing endothelial cells on an ECM produced by pericytes, astrocytes or a serial combination of both. The last-mentioned was found to be more in vivo-like. We investigated the role of the composition and morphology of ECM supra-structures in maintaining BBB function. The composition was analysed by protein analysis (enzyme-linked immunosorbent assay) and the ultrastructure of generated matrices was analysed by transmission electron microscopy including immunogold labelling. We could show by electric cell-substrate impedance sensing measurements that pericytes and combined matrices significantly improved the barrier tightness of porcine brain capillary endothelial cells (PBCEC). The increase of the resistance was verified by enhanced expression of tight junction proteins. Thus, for the first time, we have shown that barrier integrity is strictly controlled by the ECM, which is a product of all cells involved in the secretion of ECM components and their modification by corresponding cells. Moreover, we have demonstrated that complex matrices by the various cells of the BBB induce barrier marker enzymes in PBCEC, such as alkaline phosphatase. PMID:27053246

  11. Impact of diabetes in blood-testis and blood-brain barriers: resemblances and differences.

    PubMed

    Alves, Marco G; Oliveira, Pedro F; Socorro, Silvia; Moreira, Paula I

    2012-11-01

    Blood-tissue barriers prevent an uncontrolled exchange of large molecules between adjacent but metabolically separated compartments. There are several known barriers and two of the most important and tightest blood-tissue barriers are the blood-testis barrier (BTB) and the blood-brain barrier (BBB). Under normal conditions these barriers, formed by tight junctions between adjacent cells, control the entry of substances and metabolites. However, hyperglycemia and other diabetes-related complications, such as hypertension, impair the function of these biological barriers with dramatic consequences. Although both, BBB and BTB, are responsible for the maintenance of different biological processes, they have some remarkable similarities not always explored when looking at metabolic-related diseases such as diabetes. These barriers possess their own glucose sensing machinery, suffer a tied hormonal control and have specific mechanisms to counteract hyper- and hypoglycemia. In BBB and BTB the insulin signaling is also distinct from other tissues and organs thus evidencing their importance in protecting against or exacerbating the effects of diabetes on glucose metabolism. The control of glucose and lactate levels in brain and testis highlights the role of these barriers in protecting against peripheral glucose and lactate fluctuations that occur in the diabetic individual. We review the role of BBB and BTB in the control of glucose and metabolic dysfunction caused by diabetes in the brain and seminiferous epithelium. Gaining a better understanding of the molecular mechanisms through which glucose metabolism disrupts BBB and BTB function may highlight new opportunities for the treatment of diabetic complications in brain and male reproductive function. PMID:22934551

  12. The impact of microglial activation on blood-brain barrier in brain diseases

    PubMed Central

    da Fonseca, Anna Carolina Carvalho; Matias, Diana; Garcia, Celina; Amaral, Rackele; Geraldo, Luiz Henrique; Freitas, Catarina; Lima, Flavia Regina Souza

    2014-01-01

    The blood-brain barrier (BBB), constituted by an extensive network of endothelial cells (ECs) together with neurons and glial cells, including microglia, forms the neurovascular unit (NVU). The crosstalk between these cells guarantees a proper environment for brain function. In this context, changes in the endothelium-microglia interactions are associated with a variety of inflammation-related diseases in brain, where BBB permeability is compromised. Increasing evidences indicate that activated microglia modulate expression of tight junctions, which are essential for BBB integrity and function. On the other hand, the endothelium can regulate the state of microglial activation. Here, we review recent advances that provide insights into interactions between the microglia and the vascular system in brain diseases such as infectious/inflammatory diseases, epilepsy, ischemic stroke and neurodegenerative disorders. PMID:25404894

  13. Focused ultrasound-mediated drug delivery through the blood-brain barrier.

    PubMed

    Burgess, Alison; Shah, Kairavi; Hough, Olivia; Hynynen, Kullervo

    2015-05-01

    Despite recent advances in blood-brain barrier (BBB) research, it remains a significant hurdle for the pharmaceutical treatment of brain diseases. Focused ultrasound (FUS) is one method to transiently increase permeability of the BBB to promote drug delivery to specific brain regions. An introduction to the BBB and a brief overview of the methods, which can be used to circumvent the BBB to promote drug delivery, is provided. In particular, we discuss the advantages and limitations of FUS technology and the efficacy of FUS-mediated drug delivery in models of disease. MRI for targeting and evaluating FUS treatments, combined with administration of microbubbles, allows for transient, reproducible BBB opening. The integration of a real-time acoustic feedback controller has improved treatment safety. Successful clinical translation of FUS has the potential to transform the treatment of brain disease worldwide without requiring the development of new pharmaceutical agents. PMID:25936845

  14. Automated Protein Localization of Blood Brain Barrier Vasculature in Brightfield IHC Images.

    PubMed

    Soans, Rajath E; Lim, Diane C; Keenan, Brendan T; Pack, Allan I; Shackleford, James A

    2016-01-01

    In this paper, we present an objective method for localization of proteins in blood brain barrier (BBB) vasculature using standard immunohistochemistry (IHC) techniques and bright-field microscopy. Images from the hippocampal region at the BBB are acquired using bright-field microscopy and subjected to our segmentation pipeline which is designed to automatically identify and segment microvessels containing the protein glucose transporter 1 (GLUT1). Gabor filtering and k-means clustering are employed to isolate potential vascular structures within cryosectioned slabs of the hippocampus, which are subsequently subjected to feature extraction followed by classification via decision forest. The false positive rate (FPR) of microvessel classification is characterized using synthetic and non-synthetic IHC image data for image entropies ranging between 3 and 8 bits. The average FPR for synthetic and non-synthetic IHC image data was found to be 5.48% and 5.04%, respectively. PMID:26828723

  15. Astrocytic laminin regulates pericyte differentiation and maintains blood brain barrier integrity

    NASA Astrophysics Data System (ADS)

    Yao, Yao; Chen, Zu-Lin; Norris, Erin H.; Strickland, Sidney

    2014-03-01

    Blood brain barrier (BBB) breakdown is not only a consequence of but also contributes to many neurological disorders, including stroke and Alzheimer’s disease. How the basement membrane (BM) contributes to the normal functioning of the BBB remains elusive. Here we use conditional knockout mice and an acute adenovirus-mediated knockdown model to show that lack of astrocytic laminin, a brain-specific BM component, induces BBB breakdown. Using functional blocking antibody and RNAi, we further demonstrate that astrocytic laminin, by binding to integrin α2 receptor, prevents pericyte differentiation from the BBB-stabilizing resting stage to the BBB-disrupting contractile stage, and thus maintains the integrity of BBB. Additionally, loss of astrocytic laminin decreases aquaporin-4 (AQP4) and tight junction protein expression. Altogether, we report a critical role for astrocytic laminin in BBB regulation and pericyte differentiation. These results indicate that astrocytic laminin maintains the integrity of BBB through, at least in part, regulation of pericyte differentiation.

  16. Molecular targets in radiation-induced blood-brain barrier disruption

    SciTech Connect

    Nordal, Robert A.; Wong, C. Shun . E-mail: shun.wang@sw.ca

    2005-05-01

    Disruption of the blood-brain barrier (BBB) is a key feature of radiation injury to the central nervous system. Studies suggest that endothelial cell apoptosis, gene expression changes, and alteration of the microenvironment are important in initiation and progression of injury. Although substantial effort has been directed at understanding the impact of radiation on endothelial cells and oligodendrocytes, growing evidence suggests that other cell types, including astrocytes, are important in responses that include induced gene expression and microenvironmental changes. Endothelial apoptosis is important in early BBB disruption. Hypoxia and oxidative stress in the later period that precedes tissue damage might lead to astrocytic responses that impact cell survival and cell interactions. Cell death, gene expression changes, and a toxic microenvironment can be viewed as interacting elements in a model of radiation-induced disruption of the BBB. These processes implicate particular genes and proteins as targets in potential strategies for neuroprotection.

  17. Automated Protein Localization of Blood Brain Barrier Vasculature in Brightfield IHC Images

    PubMed Central

    Keenan, Brendan T.; Pack, Allan I.; Shackleford, James A.

    2016-01-01

    In this paper, we present an objective method for localization of proteins in blood brain barrier (BBB) vasculature using standard immunohistochemistry (IHC) techniques and bright-field microscopy. Images from the hippocampal region at the BBB are acquired using bright-field microscopy and subjected to our segmentation pipeline which is designed to automatically identify and segment microvessels containing the protein glucose transporter 1 (GLUT1). Gabor filtering and k-means clustering are employed to isolate potential vascular structures within cryosectioned slabs of the hippocampus, which are subsequently subjected to feature extraction followed by classification via decision forest. The false positive rate (FPR) of microvessel classification is characterized using synthetic and non-synthetic IHC image data for image entropies ranging between 3 and 8 bits. The average FPR for synthetic and non-synthetic IHC image data was found to be 5.48% and 5.04%, respectively. PMID:26828723

  18. Signaled drug delivery and transport across the blood-brain barrier.

    PubMed

    Hinow, Peter; Radunskaya, Ami; Mackay, Sean M; Reynolds, John N J; Schroeder, Morgan; Tan, Eng Wui; Tucker, Ian G

    2016-09-01

    We use a mathematical model to describe the delivery of a drug to a specific region of the brain. The drug is carried by liposomes that can release their cargo by application of focused ultrasound (US). Thereupon, the drug is absorbed through the endothelial cells that line the brain capillaries and form the physiologically important blood-brain barrier (BBB). We present a compartmental model of a capillary that is able to capture the complex binding and transport processes the drug undergoes in the blood plasma and at the BBB. We apply this model to the delivery of levodopa (L-dopa, used to treat Parkinson's disease) and doxorubicin (an anticancer agent). The goal is to optimize the delivery of drug while at the same time minimizing possible side effects of the US. PMID:26572864

  19. Selective Gelatinase Inhibitor Neuroprotective Agents Cross the Blood-Brain Barrier

    PubMed Central

    2012-01-01

    SB-3CT, a potent and selective inhibitor of matrix metalloproteinase-2 and -9, has shown efficacy in several animal models of neurological diseases. One of the greatest challenges in the development of therapeutics for neurological diseases is the inability of drugs to cross the blood-brain barrier. A sensitive bioanalytical method based on ultraperformance liquid chromatography with multiple-reaction monitoring detection was developed to measure levels of SB-3CT, its active metabolite, the α-methyl analogue, and its p-hydroxy metabolite in plasma and brain. The compounds are rapidly absorbed and are readily distributed to the brain. The pharmacokinetic properties of these gelatinase inhibitors and the efficacy shown by SB-3CT in animal models of stroke, subarachnoid hemorrhage, and spinal cord injury indicate that this class of compounds holds considerable promise in the treatment of diseases of the central nervous system. PMID:23077716

  20. Mini review on blood-brain barrier penetration of pyridinium aldoximes.

    PubMed

    Kalász, H; Nurulain, S M; Veress, G; Antus, S; Darvas, F; Adeghate, E; Adem, A; Hashemi, F; Tekes, K

    2015-02-01

    This paper reviews the blood-brain barrier (BBB) penetration of newly developed pyridinium aldoximes. Pyridinium aldoximes are highly charged hydrophilic compounds used in the treatment of subjects exposed to organophosphonates because they are effective as acetylcholinesterase reactivators. Pyridinium aldoximes have antidotal effects against poisoning with cholinesterase inhibitors, a frequent problem affecting people working with organophosphate-based insecticides and pesticides. Toxic organophosphonate products such as sarin and tabun can be used by terrorists as chemical warfare agents. This poses a severe challenge to all innocent and peace-loving people worldwide. This review gives a brief summary of BBB transporters and description of the current in vitro and in vivo methods for the characterization of BBB penetration of established and novel pyridinium aldoximes. The authors provide a putative mechanism of penetration, outline some future ways of formulation and discuss the possible advantages and disadvantages of increasing BBB penetration. PMID:25291712

  1. PRDX6 controls multiple sclerosis by suppressing inflammation and blood brain barrier disruption

    PubMed Central

    Yun, Hyung-Mun; Park, Kyung-Ran; Kim, Eun-Cheol; Hong, Jin Tae

    2015-01-01

    Multiple sclerosis (MS) is a complex disease with an unknown etiology and has no effective medications despite extensive research. Antioxidants suppress oxidative damages which are implicated in the pathogenesis of MS. In this study, we showed that the expression of an antioxidant protein peroxiredoxin 6 (PRDX6) is markedly increased in spinal cord of mice with experimental autoimmune encephalomyelitis (EAE) compared to other PRDXs. PRDX6 transgenic (Tg) mice displayed a significant decrease in clinical severity and attenuated demyelination in EAE compared to wide type mice. The increased PRDX6 expression in astrocytes of EAE mice and MS patients reduced MMP9 expression, fibrinogen leakage, chemokines, and free radical stress, leading to reduction in blood-brain-barrier (BBB) disruption, peripheral immune cell infiltration, and neuroinflammation. Together, these findings suggest that PRDX6 expression may represent a therapeutic way to restrict inflammation in the central nervous system and potentiate oligodendrocyte survival, and suggest a new molecule for neuroprotective therapies in MS. PMID:26327204

  2. PRDX6 controls multiple sclerosis by suppressing inflammation and blood brain barrier disruption.

    PubMed

    Yun, Hyung-Mun; Park, Kyung-Ran; Kim, Eun-Cheol; Hong, Jin Tae

    2015-08-28

    Multiple sclerosis (MS) is a complex disease with an unknown etiology and has no effective medications despite extensive research. Antioxidants suppress oxidative damages which are implicated in the pathogenesis of MS. In this study, we showed that the expression of an antioxidant protein peroxiredoxin 6 (PRDX6) is markedly increased in spinal cord of mice with experimental autoimmune encephalomyelitis (EAE) compared to other PRDXs. PRDX6 transgenic (Tg) mice displayed a significant decrease in clinical severity and attenuated demyelination in EAE compared to wide type mice. The increased PRDX6 expression in astrocytes of EAE mice and MS patients reduced MMP9 expression, fibrinogen leakage, chemokines, and free radical stress, leading to reduction in blood-brain-barrier (BBB) disruption, peripheral immune cell infiltration, and neuroinflammation. Together, these findings suggest that PRDX6 expression may represent a therapeutic way to restrict inflammation in the central nervous system and potentiate oligodendrocyte survival, and suggest a new molecule for neuroprotective therapies in MS. PMID:26327204

  3. Tailored delivery of analgesic ziconotide across a blood brain barrier model using viral nanocontainers

    PubMed Central

    Anand, Prachi; O’Neil, Alison; Lin, Emily; Douglas, Trevor; Holford, Mandë

    2015-01-01

    The blood brain barrier (BBB) is often an insurmountable obstacle for a large number of candidate drugs, including peptides, antibiotics, and chemotherapeutic agents. Devising an adroit delivery method to cross the BBB is essential to unlocking widespread application of peptide therapeutics. Presented here is an engineered nanocontainer for delivering peptidic drugs across the BBB encapsulating the analgesic marine snail peptide ziconotide (Prialt®). We developed a bi-functional viral nanocontainer based on the Salmonella typhimurium bacteriophage P22 capsid, genetically incorporating ziconotide in the interior cavity, and chemically attaching cell penetrating HIV-Tat peptide on the exterior of the capsid. Virus like particles (VLPs) of P22 containing ziconotide were successfully transported in several BBB models of rat and human brain microvascular endothelial cells (BMVEC) using a recyclable noncytotoxic endocytic pathway. This work demonstrates proof in principle for developing a possible alternative to intrathecal injection of ziconotide using a tunable VLP drug delivery nanocontainer to cross the BBB. PMID:26234920

  4. Analytical and Biological Methods for Probing the Blood-Brain Barrier

    NASA Astrophysics Data System (ADS)

    Kuhnline, Sloan; Courtney, D.; Nandi, Pradyot; Linz, Thomas H.; Aldrich, Jane V.; Audus, Kenneth L.; Lunte, Susan M.

    2012-07-01

    The blood-brain barrier (BBB) is an important interface between the peripheral and central nervous systems. It protects the brain against the infiltration of harmful substances and regulates the permeation of beneficial endogenous substances from the blood into the extracellular fluid of the brain. It can also present a major obstacle in the development of drugs that are targeted for the central nervous system. Several methods have been developed to investigate the transport and metabolism of drugs, peptides, and endogenous compounds at the BBB. In vivo methods include intravenous injection, brain perfusion, positron emission tomography, and microdialysis sampling. Researchers have also developed in vitro cell-culture models that can be employed to investigate transport and metabolism at the BBB without the complication of systemic involvement. All these methods require sensitive and selective analytical methods to monitor the transport and metabolism of the compounds of interest at the BBB.

  5. Focused ultrasound-mediated drug delivery through the blood-brain barrier

    PubMed Central

    Burgess, Alison; Shah, Kairavi; Hough, Olivia; Hynynen, Kullervo

    2015-01-01

    Despite recent advances in blood-brain barrier (BBB) research, it remains a significant hurdle for the pharmaceutical treatment of brain diseases. Focused ultrasound (FUS) is one method to transiently increase permeability of the BBB to promote drug delivery to specific brain regions. An introduction to the BBB and a brief overview of the methods which can be used to circumvent the BBB to promote drug delivery is provided. In particular, we discuss the advantages and limitations of FUS technology and the efficacy of FUS-mediated drug delivery in models of disease. MRI for targeting and evaluating FUS treatments, combined with administration of microbubbles, allows for transient, reproducible BBB opening. The integration of a real-time acoustic feedback controller has improved treatment safety. Successful clinical translation of FUS has the potential to transform the treatment of brain disease worldwide without requiring the development of new pharmaceutical agents. PMID:25936845

  6. Targeting receptor-mediated transport for delivery of biologics across the blood-brain barrier.

    PubMed

    Lajoie, Jason M; Shusta, Eric V

    2015-01-01

    Biologics are an emerging class of medicines with substantial promise to treat neurological disorders such as Alzheimer's disease, stroke, and multiple sclerosis. However, the blood-brain barrier (BBB) presents a formidable obstacle that appreciably limits brain uptake and hence the therapeutic potential of biologics following intravenous administration. One promising strategy for overcoming the BBB to deliver biologics is the targeting of endogenous receptor-mediated transport (RMT) systems that employ vesicular trafficking to transport ligands across the BBB endothelium. If a biologic is modified with an appropriate targeting ligand, it can gain improved access to the brain via RMT. Various RMT-targeting strategies have been developed over the past 20 years, and this review explores exciting recent advances, emphasizing studies that show brain targeting in vivo. PMID:25340933

  7. Tailored delivery of analgesic ziconotide across a blood brain barrier model using viral nanocontainers.

    PubMed

    Anand, Prachi; O'Neil, Alison; Lin, Emily; Douglas, Trevor; Holford, Mandë

    2015-01-01

    The blood brain barrier (BBB) is often an insurmountable obstacle for a large number of candidate drugs, including peptides, antibiotics, and chemotherapeutic agents. Devising an adroit delivery method to cross the BBB is essential to unlocking widespread application of peptide therapeutics. Presented here is an engineered nanocontainer for delivering peptidic drugs across the BBB encapsulating the analgesic marine snail peptide ziconotide (Prialt®). We developed a bi-functional viral nanocontainer based on the Salmonella typhimurium bacteriophage P22 capsid, genetically incorporating ziconotide in the interior cavity, and chemically attaching cell penetrating HIV-Tat peptide on the exterior of the capsid. Virus like particles (VLPs) of P22 containing ziconotide were successfully transported in several BBB models of rat and human brain microvascular endothelial cells (BMVEC) using a recyclable noncytotoxic endocytic pathway. This work demonstrates proof in principle for developing a possible alternative to intrathecal injection of ziconotide using a tunable VLP drug delivery nanocontainer to cross the BBB. PMID:26234920

  8. Changes in blood-brain barrier function modify the neuroendocrine response to circulating substances.

    PubMed

    Jezová, D; Johansson, B B; Oprsalová, Z; Vigas, M

    1989-04-01

    It is known that various experimental, pathological and even physiological situations may be accompanied by transient increases in blood-brain barrier (BBB) permeability. The hypothesis that under such conditions the blood-borne substances can reach the active sites in the brain in concentrations high enough to influence central control of hormone release was verified in these studies. A suitable experimental model of BBB opening by protamine sulfate administration in conscious rats was introduced. Using this model it was shown that the dopaminergic blocker domperidone inhibited apomorphine-induced ACTH release if permeability of the BBB was increased, but not under normal conditions. It is suggested that the changes in BBB function can modify the neuroendocrine response also to other circulating substances and this may be an important, until now unconsidered phenomenon in neuroendocrine research. PMID:2541363

  9. Blood-brain barrier disruption by continuous-wave radio frequency radiation.

    PubMed

    Sirav, Bahriye; Seyhan, Nesrin

    2009-01-01

    The increasing use of cellular phones and the increasing number of associated base stations are becoming a widespread source of non ionizing electromagnetic radiation. Some biological effects are likely to occur even at low-level EM fields. This study was designed to investigate the effects of 900 and 1,800 MHz Continuous Wave Radio Frequency Radiation (CW RFR) on the permeability of Blood Brain Barrier (BBB) of rats. Results have shown that 20 min RFR exposure of 900 and 1,800 MHz induces an effect and increases the permeability of BBB of male rats. There was no change in female rats. The scientific evidence on RFR safety or harm remains inconclusive. More studies are needed to demonstrate the effects of RFR on the permeability of BBB and the mechanisms of that breakdown. PMID:19811403

  10. In Vitro and In Vivo Blood-Brain Barrier Models to Study West Nile Virus Pathogenesis.

    PubMed

    Kumar, Mukesh; Nerurkar, Vivek R

    2016-01-01

    The blood-brain barrier (BBB), a specialized interface between the peripheral blood circulation and the central nervous system, specifically regulates molecular and cellular flux between the two. It plays a critical role in the maintenance of brain hemostasis. The BBB restricts the entry of pathogens into the brain, and thus its permeability is a critical factor that determines their central effects. Once the permeability of BBB is compromised, it has serious implications in the etiology of many brain pathologies including West Nile virus (WNV) disease. In this chapter, we describe protocols for preparation, maintenance, infection and permeability measurement of monolayer and bilayer in vitro BBB models to study WNV pathogenesis. We also describe Evans blue dye assay, a well-established method to test vascular permeability in vivo after WNV infection. PMID:27188553

  11. Tailored delivery of analgesic ziconotide across a blood brain barrier model using viral nanocontainers

    NASA Astrophysics Data System (ADS)

    Anand, Prachi; O'Neil, Alison; Lin, Emily; Douglas, Trevor; Holford, Mandë

    2015-08-01

    The blood brain barrier (BBB) is often an insurmountable obstacle for a large number of candidate drugs, including peptides, antibiotics, and chemotherapeutic agents. Devising an adroit delivery method to cross the BBB is essential to unlocking widespread application of peptide therapeutics. Presented here is an engineered nanocontainer for delivering peptidic drugs across the BBB encapsulating the analgesic marine snail peptide ziconotide (Prialt®). We developed a bi-functional viral nanocontainer based on the Salmonella typhimurium bacteriophage P22 capsid, genetically incorporating ziconotide in the interior cavity, and chemically attaching cell penetrating HIV-Tat peptide on the exterior of the capsid. Virus like particles (VLPs) of P22 containing ziconotide were successfully transported in several BBB models of rat and human brain microvascular endothelial cells (BMVEC) using a recyclable noncytotoxic endocytic pathway. This work demonstrates proof in principle for developing a possible alternative to intrathecal injection of ziconotide using a tunable VLP drug delivery nanocontainer to cross the BBB.

  12. Delayed blood-brain barrier disruption after shallow-water diving demonstrated by magnetic resonance imaging.

    PubMed

    Hadanny, Amir; Tal, Sigal; Fishlev, Gregori; Bechor, Yair; Efrati, Shai

    2015-06-01

    A 22-year-old diver presented to our emergency room complaining of headaches and left side numbness three days after diving to a depth of 6 metres for 25 minutes. On examination, he had left-sided hypaesthesia, and a post-contrast FLAIR brain MRI sequence revealed significant diffuse meningeal enhancement, indicating blood-brain-barrier (BBB) disruption. The patient was treated with hyperbaric oxygen; the initial four sessions resulted in only partial symptom improvement correlating with partial improvement in the MRI findings. Ten additional hyperbaric treatments resulted in complete resolution of the symptoms and normalization of MRI findings. The main aim of this case report is to present a probable, atypical, delayed-onset case of shallow-water decompression sickness culminating in significant BBB damage, which was demonstrated by special MRI techniques. PMID:26165534

  13. Development of an in vitro blood-brain barrier model-cytotoxicity of mercury and aluminum.

    PubMed

    Toimela, Tarja; Mäenpää, Hanna; Mannerström, Marika; Tähti, Hanna

    2004-02-15

    In this study, in vitro blood-brain barrier (BBB) models composed of two different cell types were compared. The aim of our study was to find an alternative human cell line that could be used in BBB models. Inorganic and organic mercury and aluminum were studied as model chemicals in the testing of the system. BBB models were composed of endothelial RBE4 cell line or retinal pigment epithelial (RPE) cell line ARPE-19 and neuronal SH-SY5Y cells as target cells. Glial U-373 MG cells were included in part of the tests to induce the formation of a tighter barrier. Millicell CM filter inserts were coated with rat-tail collagen, and RBE4 or ARPE-19 cells were placed on the filters at the density of 3.5-4 x 10(5) cells/filter. During culture, the state of confluency was microscopically observed and confirmed by the measurement of electrical resistance caused by the developing cell layer. The target cells, SH-SY5Y neuroblastoma cells, were plated on the bottom of cell culture wells at the density of 100000 cells/cm(2). In part of the studies, glial U-373 MG cells were placed on the under side of the membrane filter. When confluent filters with ARPE-19 or RBE4 cells were placed on top of the SH-SY5Y cells, different concentrations of mercuric chloride, methyl mercury chloride, and aluminum chloride were added into the filter cups along with a fluorescent tracer. Exposure time was 24 h, after which the cytotoxicity in the SH-SY5Y cell layer, as well as in the ARPE-19 or RBE4 cell layer, was evaluated by the luminescent measurement of total ATP. The leakage of the fluorescent tracer was also monitored. The results showed that both barrier cell types were induced by glial cells. Inorganic and organic mercury caused a leakage of the dye and cytotoxicity in SH-SY5Y cells. Especially, methyl mercury chloride could exert an effect on target cells before any profound cytotoxicity in barrier cells could be seen. Aluminum did not cause any leakage in the barrier cell layer, and even

  14. Immunogold labeling reveals subcellular localisation of silica nanoparticles in a human blood-brain barrier model

    NASA Astrophysics Data System (ADS)

    Ye, Dong; Anguissola, Sergio; O'Neill, Tiina; Dawson, Kenneth A.

    2015-05-01

    Subcellular location of nanoparticles has been widely investigated with fluorescence microscopy, via fluorescently labeled antibodies to visualise target antigens in cells. However, fluorescence microscopy, such as confocal or live cell imaging, has generally limited 3D spatial resolution. Conventional electron microscopy can be useful in bridging resolution gap, but still not ideal in resolving subcellular organelle identities. Using the pre-embedding immunogold electron microscopic imaging, we performed accurate examination of the intracellular trafficking and gathered further evidence of transport mechanisms of silica nanoparticles across a human in vitro blood-brain barrier model. Our approach can effectively immunolocalise a variety of intracellular compartments and provide new insights into the uptake and subcellular transport of nanoparticles.Subcellular location of nanoparticles has been widely investigated with fluorescence microscopy, via fluorescently labeled antibodies to visualise target antigens in cells. However, fluorescence microscopy, such as confocal or live cell imaging, has generally limited 3D spatial resolution. Conventional electron microscopy can be useful in bridging resolution gap, but still not ideal in resolving subcellular organelle identities. Using the pre-embedding immunogold electron microscopic imaging, we performed accurate examination of the intracellular trafficking and gathered further evidence of transport mechanisms of silica nanoparticles across a human in vitro blood-brain barrier model. Our approach can effectively immunolocalise a variety of intracellular compartments and provide new insights into the uptake and subcellular transport of nanoparticles. Electronic supplementary information (ESI) available: Nanoparticle characterisation data, preservation of cellular structures, staining controls, optimisation of size amplification via the silver enhancement, and more imaging results from anti-clathrin and anti-caveolin 1

  15. Blood-brain barrier transport kinetics of the cyclic depsipeptide mycotoxins beauvericin and enniatins.

    PubMed

    Taevernier, Lien; Bracke, Nathalie; Veryser, Lieselotte; Wynendaele, Evelien; Gevaert, Bert; Peremans, Kathelijne; De Spiegeleer, Bart

    2016-09-01

    The cyclic depsipeptide mycotoxins beauvericin and enniatins are capable of reaching the systemic circulation through various routes of exposure and are hence capable of exerting central nervous system (CNS) effects, if they are able to pass the blood-brain barrier (BBB), which was the main objective of this study. Quantification of the mycotoxins was performed using an in-house developed and validated bio-analytical UHPLC-MS/MS method. Prior to the BBB experiments, the metabolic stability of the mycotoxins was evaluated in vitro in mouse serum and brain homogenate. The BBB permeation kinetics of beauvericin and enniatins were studied using an in vivo mice model, applying multiple time regression for studying the blood-to-brain influx. Additionally, capillary depletion was applied to obtain the fraction of the peptides really entering the brain parenchyma and the fraction loosely adhered to the brain capillary wall. Finally, also the brain-to-blood efflux transport kinetics was studied. Metabolic stability data indicated that the investigated mycotoxins were stable during the duration of the in vivo study. The brain influx study showed that beauvericin and enniatins are able to cross the blood-brain barrier in mice: using the Gjedde-Patlak biphasic model, it was shown that all investigated mycotoxins exert a high initial influx rate into the brain (K1 ranging from 11 to 53μL/(g×min)), rapidly reaching a plateau. After penetration, the mycotoxins reached the brain parenchyma (95%) with only a limited amount residing in the capillaries (5%). Negligible efflux (<0.005min(-1)) from the brain was observed in the 15min post-intracerebroventricular injection. PMID:27349679

  16. Stepwise Recruitment of Transcellular and Paracellular Pathways Underlies Blood-Brain Barrier Breakdown in Stroke

    PubMed Central

    Knowland, Daniel; Arac, Ahmet; Sekiguchi, Kohei; Hsu, Martin; Lutz, Sarah E.; Perrino, John; Steinberg, Gary K.; Barres, Ben A.; Nimmerjahn, Axel; Agalliu, Dritan

    2014-01-01

    SUMMARY Brain endothelial cells form a paracellular and transcellular barrier to many blood-borne solutes via tight junctions (TJs) and scarce endocytotic vesicles. The blood-brain barrier (BBB) plays a pivotal role in the healthy and diseased CNS. BBB damage after ischemic stroke contributes to increased mortality, yet the contributions of paracellular and transcellular mechanisms to this process in vivo are unknown. We have created a novel transgenic mouse strain whose endothelial TJs are labeled with eGFP and have imaged dynamic TJ changes and fluorescent tracer leakage across the BBB in vivo, using two-photon microscopy in the t-MCAO stroke model. Although barrier function is impaired as early as 6 h post-stroke, TJs display profound structural defects only after two days. Conversely, the number of endothelial caveolae and transcytosis rate increase as early as 6 h post-stroke. Therefore, stepwise impairment of transcellular followed by paracellular barrier mechanisms accounts for the BBB deficits in stroke. PMID:24746419

  17. THE ROLE OF MULTIDRUG RESISTANCE ASSOCIATED PROTEIN (MRP) IN THE BLOOD-BRAIN BARRIER AND OPIOID ANALGESIA

    PubMed Central

    Su, Wendy; Pasternak, Gavril W.

    2013-01-01

    The blood brain barrier protects the brain from circulating compounds and drugs. The ATP-binding cassette (ABC) transporter P-glycoprotein (Pgp) is involved with the barrier, both preventing the influx of agent from the blood into the brain and facilitating the efflux of compounds from the brain into the blood, raising the possibility of a similar role for other transporters. Multidrug resistance associated protein (MRP), a 190 kDa protein similar to Pgp is also ABC transport that has been implicated in the blood brain barrier. The current study explores its role in opioid action. Immunohistochemically, it is localized in the choroid plexus in ratsand can be selectively downregulated by antisense treatment at both the level of mRNA, as shown by RT-PCR, and protein, as demonstrated immunohistochemically. Behaviorally, downregulation of MRP significantly enhances the analgesic potency of systemic morphine in MRP knockout mice and in antisense-treated rats by lowering the blood brain barrier. Following intracerebroventricular administration, a number of compounds, including some opioids, are rapidly secreted from the brain into the blood where they contribute to the overall analgesic effects by activating peripheral systems. MRP plays a role in this efflux. Downregulating MRP expression leads to a corresponding decrease in the transport and a diminished analgesic response from opioids administered intracerebroventricularly. Thus, the transporter protein MRP plays a role in maintaining the blood-brain barrier and modulates the activity of opioids. PMID:23508590

  18. Diesel exhaust particles induce oxidative stress, proinflammatory signaling, and P-glycoprotein up-regulation at the blood-brain barrier

    PubMed Central

    Hartz, Anika M. S.; Bauer, Björn; Block, Michelle L.; Hong, Jau-Shyong; Miller, David S.

    2008-01-01

    Here, we report that diesel exhaust particles (DEPs), a major constituent of urban air pollution, affect blood-brain barrier function at the tissue, cellular, and molecular levels. Isolated rat brain capillaries exposed to DEPs showed increased expression and transport activity of the key drug efflux transporter, P-glycoprotein (6 h EC50 was ∼5 μg/ml). Up-regulation of P-glycoprotein was abolished by blocking transcription or protein synthesis. Inhibition of NADPH oxidase or pretreatment of capillaries with radical scavengers ameliorated DEP-induced P-glycoprotein up-regulation, indicating a role for reactive oxygen species in signaling. DEP exposure also increased brain capillary tumor necrosis factor-α (TNF-α) levels. DEP-induced P-glycoprotein up-regulation was abolished when TNF-receptor 1 (TNF-R1) was blocked and was not evident in experiments with capillaries from TNF-R1 knockout mice. Inhibition of JNK, but not NF-κB, blocked DEP-induced P-glycoprotein up-regulation, indicating a role for AP-1 in the signaling pathway. Consistent with this, DEPs increased phosphorylation of c-jun. Together, our results show for the first time that a component of air pollution, DEPs, alters blood-brain barrier function through oxidative stress and proinflammatory cytokine production. These experiments disclose a novel blood-brain barrier signaling pathway, with clear implications for environmental toxicology, CNS pathology, and the pharmacotherapy of CNS disorders.—Hartz, A. M. S., Bauer, B., Block, M. L., Hong, J.-S., Miller, D.-S. Diesel exhaust particles induce oxidative stress, proinflammatory signaling, and P-glycoprotein up-regulation at the blood-brain barrier. PMID:18474546

  19. Hydrophilic bile acids protect human blood-brain barrier endothelial cells from disruption by unconjugated bilirubin: an in vitro study

    PubMed Central

    Palmela, Inês; Correia, Leonor; Silva, Rui F. M.; Sasaki, Hiroyuki; Kim, Kwang S.; Brites, Dora; Brito, Maria A.

    2015-01-01

    Ursodeoxycholic acid and its main conjugate glycoursodeoxycholic acid are bile acids with neuroprotective properties. Our previous studies demonstrated their anti-apoptotic, anti-inflammatory, and antioxidant properties in neural cells exposed to elevated levels of unconjugated bilirubin (UCB) as in severe jaundice. In a simplified model of the blood-brain barrier, formed by confluent monolayers of a cell line of human brain microvascular endothelial cells, UCB has shown to induce caspase-3 activation and cell death, as well as interleukin-6 release and a loss of blood-brain barrier integrity. Here, we tested the preventive and restorative effects of these bile acids regarding the disruption of blood-brain barrier properties by UCB in in vitro conditions mimicking severe neonatal hyperbilirubinemia and using the same experimental blood-brain barrier model. Both bile acids reduced the apoptotic cell death induced by UCB, but only glycoursodeoxycholic acid significantly counteracted caspase-3 activation. Bile acids also prevented the upregulation of interleukin-6 mRNA, whereas only ursodeoxycholic acid abrogated cytokine release. Regarding barrier integrity, only ursodeoxycholic acid abrogated UCB-induced barrier permeability. Better protective effects were obtained by bile acid pre-treatment, but a strong efficacy was still observed by their addition after UCB treatment. Finally, both bile acids showed ability to cross confluent monolayers of human brain microvascular endothelial cells in a time-dependent manner. Collectively, data disclose a therapeutic time-window for preventive and restorative effects of ursodeoxycholic acid and glycoursodeoxycholic acid against UCB-induced blood-brain barrier disruption and damage to human brain microvascular endothelial cells. PMID:25821432

  20. Blood-brain barrier permeable gold nanoparticles: an efficient delivery platform for enhanced malignant glioma therapy and imaging.

    PubMed

    Cheng, Yu; Dai, Qing; Morshed, Ramin A; Fan, Xiaobing; Wegscheid, Michelle L; Wainwright, Derek A; Han, Yu; Zhang, Lingjiao; Auffinger, Brenda; Tobias, Alex L; Rincón, Esther; Thaci, Bart; Ahmed, Atique U; Warnke, Peter C; He, Chuan; Lesniak, Maciej S

    2014-12-29

    The blood-brain barrier (BBB) remains a formidable obstacle in medicine, preventing efficient penetration of chemotherapeutic and diagnostic agents to malignant gliomas. Here, a transactivator of transcription (TAT) peptide-modified gold nanoparticle platform (TAT-Au NP) with a 5 nm core size is demonstrated to be capable of crossing the BBB efficiently and delivering cargoes such as the anticancer drug doxorubicin (Dox) and Gd(3+) contrast agents to brain tumor tissues. Treatment of mice bearing intracranial glioma xenografts with pH-sensitive Dox-conjugated TAT-Au NPs via a single intravenous administration leads to significant survival benefit when compared to the free Dox. Furthermore, it is demonstrated that TAT-Au NPs are capable of delivering Gd(3+) chelates for enhanced brain tumor imaging with a prolonged retention time of Gd(3+) when compared to the free Gd(3+) chelates. Collectively, these results show promising applications of the TAT-Au NPs for enhanced malignant brain tumor therapy and non-invasive imaging. PMID:25104165

  1. Blood-Brain Barrier Permeable Gold Nanoparticles: An Efficient Delivery Platform for Enhanced Malignant Glioma Therapy and Imaging

    PubMed Central

    Cheng, Yu; Dai, Qing; Morshed, Ramin; Fan, Xiaobing; Wegscheid, Michelle L.; Wainwright, Derek A.; Han, Yu; Zhang, Lingjiao; Auffinger, Brenda; Tobias, Alex L.; Rincón, Esther; Thaci, Bart; Ahmed, Atique U.; Warnke, Peter; He, Chuan

    2014-01-01

    The blood-brain barrier (BBB) remains a formidable obstacle in medicine, preventing efficient penetration of chemotherapeutic and diagnostic agents to malignant gliomas. Here, we demonstrate that a transactivator of transcription (TAT) peptide-modified gold nanoparticle platform (TAT-Au NP) with a 5 nm core size is capable of crossing the BBB efficiently and delivering cargoes such as the anticancer drug doxorubicin (Dox) and Gd3+ contrast agents to brain tumor tissues. Treatment of mice bearing intracranial glioma xenografts with pH-sensitive Dox-conjugated TAT-Au NPs via a single intravenous administration leads to significant survival benefit when compared to the free Dox. Furthermore, we demonstrate that TAT-Au NPs are capable of delivering Gd3+ chelates for enhanced brain tumor imaging with a prolonged retention time of Gd3+ when compared to the free Gd3+ chelates. Collectively, these results show promising applications of the TAT-Au NPs for enhanced malignant brain tumor therapy and non-invasive imaging. PMID:25104165

  2. Iron transport across the blood-brain barrier; Development, neurovascular regulation and cerebral amyloid angiopathy

    PubMed Central

    McCarthy, Ryan C; Kosman, Daniel J

    2014-01-01

    There are two barriers for iron entry into the brain: 1) the brain-cerebrospinal fluid (CSF) barrier and 2) the blood-brain barrier (BBB). Here, we review the literature on developmental iron accumulation by the brain, focusing on the transport of iron through the brain microvascular endothelial cells (BMVEC) of the BBB. We review the iron trafficking proteins which may be involved in the iron flux across BMVEC and discuss the plausible mechanisms of BMVEC iron uptake and efflux. We suggest a model for how BMVEC iron uptake and efflux are regulated and a mechanism by which the majority of iron is trafficked across the developing BBB under the direct guidance of neighboring astrocytes. Thus, we place brain iron uptake in the context of the neurovascular unit of the adult brain. Last, we propose that BMVEC iron is involved in the aggregation of amyloid-β peptides leading to the progression of cerebral amyloid angiopathy which often occurs prior to dementia and the onset of Alzheimer's disease. PMID:25355056

  3. Polymeric nanoparticles assembled with microfluidics for drug delivery across the blood-brain barrier

    NASA Astrophysics Data System (ADS)

    Tavares, M. R.; de Menezes, L. R.; do Nascimento, D. F.; Souza, D. H. S.; Reynaud, F.; Marques, M. F. V.; Tavares, M. I. B.

    2016-07-01

    The blood-brain barrier (BBB) is a challenge in the treatment of some diseases, since it prevents many drugs from reaching therapeutic concentrations in the brain. In this context, there is a growing interest in nanoparticles for drug delivery, since they are able to cross this barrier and target the brain. The use of polymeric materials in the development of these nanoparticles has been extensively studied. It has already been demonstrated that these nanosystems have the ability to cross the BBB, which allows effective drug release into the brain. Biodegradable polymers provide a great advantage in the development of nanosystems, but modifications of the nanoparticles' surface is essential. The traditional batch methods lack precise control over the processes of nucleation and growth, resulting in poor control over final properties of the nanoparticles. Therefore, microfluidics could be used to achieve a better production environment for the fabrication of nano- structured drug delivery systems. This study provides a brief review of: the BBB, the polymeric nanoparticles with the ability to overcome the barrier, the properties of the most used polymeric matrices, and the nanostructured drug delivery systems assembled with microfluidics.

  4. Disruption of the blood-brain barrier exacerbates spreading depression in the locust CNS.

    PubMed

    Spong, Kristin E; Rochon-Terry, Geneviève; Money, Tomas G A; Robertson, R Meldrum

    2014-07-01

    In response to cellular stress in the nervous system of the locust (Locusta migratoria) neural function is interrupted in association with ionic disturbances propagating throughout nervous tissue (Spreading depression; SD). The insect blood-brain barrier (BBB) plays a critical role in the regulation of ion levels within the CNS. We investigated how a disruption in barrier function by transient exposure to 3M urea affects locusts' vulnerability to disturbances in ion levels. Repetitive SD was induced by bath application of ouabain and the extracellular potassium concentration ([K(+)]o) within the metathoracic ganglion (MTG) was monitored. Urea treatment increased the susceptibility to ouabain and caused a progressive impairment in the ability to maintain baseline [K(+)]o levels during episodes of repetitive SD. Additionally, using a within animal protocol we demonstrate that waves of SD, induced by high K(+), propagate throughout the MTG faster following disruption of the BBB. Lastly, we show that targeting the BBB of intact animals reduces their ability to sustain neural function during anoxic conditions. Our findings indicate that locust's ability to withstand stress is diminished following a reduction in barrier function likely due to an impairment of the ability of neural tissue to maintain ionic gradients. PMID:24837786

  5. Electroporation of Brain Endothelial Cells on Chip toward Permeabilizing the Blood-Brain Barrier.

    PubMed

    Bonakdar, Mohammad; Wasson, Elisa M; Lee, Yong W; Davalos, Rafael V

    2016-01-19

    The blood-brain barrier, mainly composed of brain microvascular endothelial cells, poses an obstacle to drug delivery to the brain. Controlled permeabilization of the constituent brain endothelial cells can result in overcoming this barrier and increasing transcellular transport across it. Electroporation is a biophysical phenomenon that has shown potential in permeabilizing and overcoming this barrier. In this study we developed a microengineered in vitro model to characterize the permeabilization of adhered brain endothelial cells to large molecules in response to applied pulsed electric fields. We found the distribution of affected cells by reversible and irreversible electroporation, and quantified the uptaken amount of naturally impermeable molecules into the cells as a result of applied pulse magnitude and number of pulses. We achieved 81 ± 1.7% (N = 6) electroporated cells with 17 ± 8% (N = 5) cell death using an electric-field magnitude of ∼580 V/cm and 10 pulses. Our results provide the proper range for applied electric-field intensity and number of pulses for safe permeabilization without significantly compromising cell viability. Our results demonstrate that it is possible to permeabilize the endothelial cells of the BBB in a controlled manner, therefore lending to the feasibility of using pulsed electric fields to increase drug transport across the BBB through the transcellular pathway. PMID:26789772

  6. Computing the blood brain barrier (BBB) diffusion coefficient: A molecular dynamics approach

    NASA Astrophysics Data System (ADS)

    Shamloo, Amir; Pedram, Maysam Z.; Heidari, Hossein; Alasty, Aria

    2016-07-01

    Various physical and biological aspects of the Blood Brain Barrier (BBB) structure still remain unfolded. Therefore, among the several mechanisms of drug delivery, only a few have succeeded in breaching this barrier, one of which is the use of Magnetic Nanoparticles (MNPs). However, a quantitative characterization of the BBB permeability is desirable to find an optimal magnetic force-field. In the present study, a molecular model of the BBB is introduced that precisely represents the interactions between MNPs and the membranes of Endothelial Cells (ECs) that form the BBB. Steered Molecular Dynamics (SMD) simulations of the BBB crossing phenomenon have been carried out. Mathematical modeling of the BBB as an input-output system has been considered from a system dynamics modeling viewpoint, enabling us to analyze the BBB behavior based on a robust model. From this model, the force profile required to overcome the barrier has been extracted for a single NP from the SMD simulations at a range of velocities. Using this data a transfer function model has been obtained and the diffusion coefficient is evaluated. This study is a novel approach to bridge the gap between nanoscale models and microscale models of the BBB. The characteristic diffusion coefficient has the nano-scale molecular effects inherent, furthermore reducing the computational costs of a nano-scale simulation model and enabling much more complex studies to be conducted.

  7. Evolutionary conservation of vertebrate blood-brain barrier chemoprotective mechanisms in Drosophila

    PubMed Central

    Mayer, Fahima; Mayer, Nasima; Chinn, Leslie; Pinsonneault, Robert L.; Kroetz, Deanna; Bainton, Roland J.

    2011-01-01

    Pharmacologic remedy of many brain diseases is difficult because of the powerful drug exclusion properties of the blood-brain barrier (BBB). Chemical isolation of the vertebrate brain is achieved through the highly integrated, anatomically compact and functionally overlapping chemical isolation processes of the BBB. These include functions that need to be coordinated between tight diffusion junctions and unidirectionally-acting xenobiotic transporters. Understanding of many of these processes has been hampered, as they are not well mimicked by ex vivo models of the BBB and have been experimentally difficult and expensive to disentangle in intact rodent models. Here we show that the Drosophila melanogaster (Dm) humoral/CNS barrier conserves the xenobiotic exclusion properties found in the vertebrate vascular endothelium. We characterize a fly ABC transporter, Mdr65, that functions similar to mammalian xenobiotic BBB transporters and show that varying its levels solely in the Dm BBB changes the inherent sensitivity of the barrier to cytotoxic pharmaceuticals. Furthermore we demonstrate orthologous function between Mdr65 and vertebrate ABC transporters by rescuing chemical protection of the Dm brain with human MDR1/Pgp. These data indicate that the ancient origins of CNS chemoprotection extend to both conserved molecular means and functionally analogous anatomic spaces that together promote CNS selective drug partition. Thus, Dm presents an experimentally tractable system for analyzing physiological properties of the BBB in an intact organism. PMID:19295159

  8. Blood-brain barrier dysfunction after primary blast injury in vitro.

    PubMed

    Hue, Christopher D; Cao, Siqi; Haider, Syed F; Vo, Kiet V; Effgen, Gwen B; Vogel, Edward; Panzer, Matthew B; Bass, Cameron R Dale; Meaney, David F; Morrison, Barclay

    2013-10-01

    The incidence of blast-induced traumatic brain injury (bTBI) has increased substantially in recent military conflicts. However, the consequences of bTBI on the blood-brain barrier (BBB), a specialized cerebrovascular structure essential for brain homeostasis, remain unknown. In this study, we utilized a shock tube driven by compressed gas to generate operationally relevant, ideal pressure profiles consistent with improvised explosive devices (IEDs). By multiple measures, the barrier function of an in vitro BBB model was disrupted following exposure to a range of controlled blast loading conditions. Trans-endothelial electrical resistance (TEER) decreased acutely in a dose-dependent manner that was most strongly correlated with impulse, as opposed to peak overpressure or duration. Significantly increased hydraulic conductivity and solute permeability post-injury further confirmed acute alterations in barrier function. Compromised ZO-1 immunostaining identified a structural basis for BBB breakdown. After blast exposure, TEER remained significantly depressed 2 days post-injury, followed by spontaneous recovery to pre-injury control levels at day 3. This study is the first to report immediate disruption of an in vitro BBB model following primary blast exposure, which may be important for the development of novel helmet designs to help mitigate the effects of blast on the BBB. PMID:23581482

  9. Borrelia burgdorferi, Host-Derived Proteases, and the Blood-Brain Barrier

    PubMed Central

    Grab, Dennis J.; Perides, George; Dumler, J. Stephen; Kim, Kee Jun; Park, Jinho; Kim, Yuri V.; Nikolskaia, Olga; Choi, Kyoung Seong; Stins, Monique F.; Kim, Kwang Sik

    2005-01-01

    Neurological manifestations of Lyme disease in humans are attributed in part to penetration of the blood-brain barrier (BBB) and invasion of the central nervous system (CNS) by Borrelia burgdorferi. However, how the spirochetes cross the BBB remains an unresolved issue. We examined the traversal of B. burgdorferi across the human BBB and systemic endothelial cell barriers using in vitro model systems constructed of human brain microvascular endothelial cells (BMEC) and EA.hy 926, a human umbilical vein endothelial cell (HUVEC) line grown on Costar Transwell inserts. These studies showed that B. burgdorferi differentially crosses human BMEC and HUVEC and that the human BMEC form a barrier to traversal. During the transmigration by the spirochetes, it was found that the integrity of the endothelial cell monolayers was maintained, as assessed by transendothelial electrical resistance measurements at the end of the experimental period, and that B. burgdorferi appeared to bind human BMEC by their tips near or at cell borders, suggesting a paracellular route of transmigration. Importantly, traversal of B. burgdorferi across human BMEC induces the expression of plasminogen activators, plasminogen activator receptors, and matrix metalloproteinases. Thus, the fibrinolytic system linked by an activation cascade may lead to focal and transient degradation of tight junction proteins that allows B. burgdorferi to invade the CNS. PMID:15664945

  10. Blood-brain barrier proteomics: towards the understanding of neurodegenerative diseases.

    PubMed

    Karamanos, Yannis; Gosselet, Fabien; Dehouck, Marie-Pierre; Cecchelli, Roméo

    2014-11-01

    The blood-brain barrier (BBB) regulates the passage of endogenous and exogenous compounds and thus contributes to the brain homeostasis with the help of well-known proteins such as tight junction proteins, plasma membrane transporters and metabolic barrier proteins. In the last decade, proteomics have emerged as supplementary tools for BBB research. The development of proteomic technologies has provided several means to extend knowledge on the BBB and to investigate additional routes for the bypass of this barrier. Proteomics approaches have been used in vivo and also using in vitro BBB models to decipher the physiological characteristics and, under stress conditions, to understand the molecular mechanisms of brain diseases. This work has demonstrated that both quantitative global and targeted proteomics approaches are powerful and provide significant information on the brain microvessel endothelium. However, current knowledge is only partial and it is necessary to increase the studies using proteomics tools that will provide additional information concerning brain pathologies or BBB metabolism. Highly sensitive, accurate and specific protein quantification by quantitative targeted proteomics appears as an essential methodology for human BBB studies. PMID:25446619

  11. A Novel Dynamic Neonatal Blood-Brain Barrier on a Chip

    PubMed Central

    Deosarkar, Sudhir P.; Prabhakarpandian, Balabhaskar; Wang, Bin; Sheffield, Joel B.; Krynska, Barbara; Kiani, Mohammad F.

    2015-01-01

    Studies of neonatal neural pathologies and development of appropriate therapeutics are hampered by a lack of relevant in vitro models of neonatal blood-brain barrier (BBB). To establish such a model, we have developed a novel blood-brain barrier on a chip (B3C) that comprises a tissue compartment and vascular channels placed side-by-side mimicking the three-dimensional morphology, size and flow characteristics of microvessels in vivo. Rat brain endothelial cells (RBEC) isolated from neonatal rats were seeded in the vascular channels of B3C and maintained under shear flow conditions, while neonatal rat astrocytes were cultured under static conditions in the tissue compartment of the B3C. RBEC formed continuous endothelial lining with a central lumen along the length of the vascular channels of B3C and exhibited tight junction formation, as measured by the expression of zonula occludens-1 (ZO-1). ZO-1 expression significantly increased with shear flow in the vascular channels and with the presence of astrocyte conditioned medium (ACM) or astrocytes cultured in the tissue compartment. Consistent with in vivo BBB, B3C allowed endfeet-like astrocyte-endothelial cell interactions through a porous interface that separates the tissue compartment containing cultured astrocytes from the cultured RBEC in the vascular channels. The permeability of fluorescent 40 kDa dextran from vascular channel to the tissue compartment significantly decreased when RBEC were cultured in the presence of astrocytes or ACM (from 41.0±0.9 x 10−6 cm/s to 2.9±1.0 x 10−6 cm/s or 1.1±0.4 x 10−6 cm/s, respectively). Measurement of electrical resistance in B3C further supports that the addition of ACM significantly improves the barrier function in neonatal RBEC. Moreover, B3C exhibits significantly improved barrier characteristics compared to the transwell model and B3C permeability was not significantly different from the in vivo BBB permeability in neonatal rats. In summary, we developed a

  12. Blood-brain barrier models and their relevance for a successful development of CNS drug delivery systems: a review.

    PubMed

    Bicker, Joana; Alves, Gilberto; Fortuna, Ana; Falcão, Amílcar

    2014-08-01

    During the research and development of new drugs directed at the central nervous system, there is a considerable attrition rate caused by their hampered access to the brain by the blood-brain barrier. Throughout the years, several in vitro models have been developed in an attempt to mimic critical functionalities of the blood-brain barrier and reliably predict the permeability of drug candidates. However, the current challenge lies in developing a model that retains fundamental blood-brain barrier characteristics and simultaneously remains compatible with the high throughput demands of pharmaceutical industries. This review firstly describes the roles of all elements of the neurovascular unit and their influence on drug brain penetration. In vitro models, including non-cell based and cell-based models, and in vivo models are herein presented, with a particular emphasis on their methodological aspects. Lastly, their contribution to the improvement of brain drug delivery strategies and drug transport across the blood-brain barrier is also discussed. PMID:24686194

  13. BLOOD-BRAIN BARRIER PERMEATION IN THE RAT DURING EXPOSURE TO LOW-POWER 1.7-GHZ MICROWAVE RADIATION

    EPA Science Inventory

    The permeability of the blood-brain barrier to high-and low-molecular-weight compounds has been measured as a function of continuous wave (CW) and pulsed microwave radiation. Adult rats, anesthetized with pentobarbital and injected intravenously with a mixture of (14C) sucrose an...

  14. Intestinal and Blood-Brain Barrier Permeability of Ginkgolides and Bilobalide: In Vitro and In Vivo Approaches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study intestinal and blood brain barrier (BBB) transport of ginkgolides A, B, C, J and bilobalide, isolated from Ginkgo biloba (Family-Ginkgoaceae), was evaluated in Caco-2 and MDR1-MDCK cell monolayer models. Transepithelial transport was examined for 2 hours in both absorptive and secretor...

  15. Ultrastructural analysis of blood-brain barrier breakdown in the peri-infarct zone in young adult and aged mice.

    PubMed

    Nahirney, Patrick C; Reeson, Patrick; Brown, Craig E

    2016-02-01

    Following ischemia, the blood-brain barrier is compromised in the peri-infarct zone leading to secondary injury and dysfunction that can limit recovery. Currently, it is uncertain what structural changes could account for blood-brain barrier permeability, particularly with aging. Here we examined the ultrastructure of early and delayed changes (3 versus 72 h) to the blood-brain barrier in young adult and aged mice (3-4 versus 18 months) subjected to photothrombotic stroke. At both time points and ages, permeability was associated with a striking increase in endothelial caveolae and vacuoles. Tight junctions were generally intact although small spaces were detected in a few cases. In young mice, ischemia led to a significant increase in pericyte process area and vessel coverage whereas these changes were attenuated with aging. Stroke led to an expansion of the basement membrane region that peaked at 3 h and partially recovered by 72 h in both age groups. Astrocyte endfeet and their mitochondria were severely swollen at both times points and ages. Our results suggest that blood-brain barrier permeability in young and aged animals is mediated by transcellular pathways (caveolae/vacuoles), rather than tight junction loss. Further, our data indicate that the effects of ischemia on pericytes and basement membrane are affected by aging. PMID:26661190

  16. Importance of dose intensity in neuro-oncology clinical trials: summary report of the Sixth Annual Meeting of the Blood-Brain Barrier Disruption Consortium.

    PubMed

    Doolittle, N D; Anderson, C P; Bleyer, W A; Cairncross, J G; Cloughesy, T; Eck, S L; Guastadisegni, P; Hall, W A; Muldoon, L L; Patel, S J; Peereboom, D; Siegal, T; Neuwelt, E A

    2001-01-01

    Therapeutic options for the treatment of malignant brain tumors have been limited, in part, because of the presence of the blood-brain barrier. For this reason, the Sixth Annual Meeting of the Blood-Brain Barrier Disruption Consortium, the focus of which was the "Importance of Dose Intensity in Neuro-Oncology Clinical Trials," was convened in April 2000, at Government Camp, Mount Hood, Oregon. This meeting, which was supported by the National Cancer Institute, the National Institute of Neurological Disorders and Stroke, and the National Institute of Deafness and Other Communication Disorders, brought together clinicians and basic scientists from across the U.S. to discuss the role of dose intensity and enhanced chemotherapy delivery in the treatment of malignant brain tumors and to design multicenter clinical trials. Optimizing chemotherapy delivery to the CNS is crucial, particularly in view of recent progress identifying certain brain tumors as chemosensitive. The discovery that specific constellations of genetic alterations can predict which tumors are chemoresponsive, and can therefore more accurately predict prognosis, has important implications for delivery of intensive, effective chemotherapy regimens with acceptable toxicities. This report summarizes the discussions, future directions, and key questions regarding dose-intensive treatment of primary CNS lymphoma, CNS relapse of systemic non-Hodgkin's lymphoma, anaplastic oligodendroglioma, high-grade glioma, and metastatic cancer of the brain. The promising role of cytoenhancers and chemoprotectants as part of dose-intensive regimens for chemosensitive brain tumors and development of improved gene therapies for malignant gliomas are discussed. PMID:11305417

  17. Is Peripheral Immunity Regulated by Blood-Brain Barrier Permeability Changes?

    PubMed Central

    Bargerstock, Erin; Puvenna, Vikram; Iffland, Philip; Falcone, Tatiana; Hossain, Mohammad; Vetter, Stephen; Man, Shumei; Dickstein, Leah; Marchi, Nicola; Ghosh, Chaitali; Carvalho-Tavares, Juliana; Janigro, Damir

    2014-01-01

    S100B is a reporter of blood-brain barrier (BBB) integrity which appears in blood when the BBB is breached. Circulating S100B derives from either extracranial sources or release into circulation by normal fluctuations in BBB integrity or pathologic BBB disruption (BBBD). Elevated S100B matches the clinical presence of indices of BBBD (gadolinium enhancement or albumin coefficient). After repeated sub-concussive episodes, serum S100B triggers an antigen-driven production of anti-S100B autoantibodies. We tested the hypothesis that the presence of S100B in extracranial tissue is due to peripheral cellular uptake of serum S100B by antigen presenting cells, which may induce the production of auto antibodies against S100B. To test this hypothesis, we used animal models of seizures, enrolled patients undergoing repeated BBBD, and collected serum samples from epileptic patients. We employed a broad array of techniques, including immunohistochemistry, RNA analysis, tracer injection and serum analysis. mRNA for S100B was segregated to barrier organs (testis, kidney and brain) but S100B protein was detected in immunocompetent cells in spleen, thymus and lymph nodes, in resident immune cells (Langerhans, satellite cells in heart muscle, etc.) and BBB endothelium. Uptake of labeled S100B by rat spleen CD4+ or CD8+ and CD86+ dendritic cells was exacerbated by pilocarpine-induced status epilepticus which is accompanied by BBBD. Clinical seizures were preceded by a surge of serum S100B. In patients undergoing repeated therapeutic BBBD, an autoimmune response against S100B was measured. In addition to its role in the central nervous system and its diagnostic value as a BBBD reporter, S100B may integrate blood-brain barrier disruption to the control of systemic immunity by a mechanism involving the activation of immune cells. We propose a scenario where extravasated S100B may trigger a pathologic autoimmune reaction linking systemic and CNS immune responses. PMID:24988410

  18. Autoregulated paracellular clearance of amyloid-β across the blood-brain barrier

    PubMed Central

    Keaney, James; Walsh, Dominic M.; O’Malley, Tiernan; Hudson, Natalie; Crosbie, Darragh E.; Loftus, Teresa; Sheehan, Florike; McDaid, Jacqueline; Humphries, Marian M.; Callanan, John J.; Brett, Francesca M.; Farrell, Michael A.; Humphries, Peter; Campbell, Matthew

    2015-01-01

    The blood-brain barrier (BBB) is essential for maintaining brain homeostasis and protecting neural tissue from damaging blood-borne agents. The barrier is characterized by endothelial tight junctions that limit passive paracellular diffusion of polar solutes and macromolecules from blood to brain. Decreased brain clearance of the neurotoxic amyloid-β (Aβ) peptide is a central event in the pathogenesis of Alzheimer’s disease (AD). Whereas transport of Aβ across the BBB can occur via transcellular endothelial receptors, the paracellular movement of Aβ has not been described. We show that soluble human Aβ(1–40) monomers can diffuse across the paracellular pathway of the BBB in tandem with a decrease in the tight junction proteins claudin-5 and occludin in the cerebral vascular endothelium. In a murine model of AD (Tg2576), plasma Aβ(1–40) levels were significantly increased, brain Aβ(1–40) levels were decreased, and cognitive function was enhanced when both claudin-5 and occludin were suppressed. Furthermore, Aβ can cause a transient down-regulation of claudin-5 and occludin, allowing for its own paracellular clearance across the BBB. Our results show, for the first time, the involvement of the paracellular pathway in autoregulated Aβ movement across the BBB and identify both claudin-5 and occludin as potential therapeutic targets for AD. These findings also indicate that controlled modulation of tight junction components at the BBB can enhance the clearance of Aβ from the brain. PMID:26491725

  19. Blood-ocular and blood-brain barrier function in streptozocin-induced diabetes in rats

    SciTech Connect

    Maeepea, O.; Karlsson, C.; Alm, A.

    1984-09-01

    Edetic acid labeled with chromium 51 was injected intravenously in normal rats and in rats with streptozocin-induced diabetes. One hour after the injection the animals were killed and the concentrations of edetic acid 51Cr in vitreous body, retina, and brain were determined. No significant difference was observed between the two groups for either tissue. In a second series, a mixture of tritiated 1-glucose and aminohippuric acid tagged with carbon 14 was injected instead of edetic acid. A substantial accumulation of aminohippuric acid 14C compared with tritiated 1-glucose was observed in the vitreous body and the brain of diabetic rats in comparison with the control group. It is concluded that untreated streptozocin-induced diabetes in rats for one to two weeks will not cause a generalized increase in the permeability of the blood-ocular or the blood-brain barriers, but organic acids may accumulate in the vitreous body as well as in the brain as a consequence of reduced outward transport through these barriers.

  20. A2A adenosine receptor regulates the human blood brain barrier permeability

    PubMed Central

    Kim, Do-Geun; Bynoe, Margaret S.

    2015-01-01

    The blood brain barrier (BBB) symbolically represents the gateway to the central nervous system. It is a single layer of specialized endothelial cells that coats the central nervous system (CNS) vasculature and physically separates the brain environment from the blood constituents, to maintain the homeostasis of the CNS. However, this protective measure is a hindrance to the delivery of therapeutics to treat neurological diseases. Here, we show that activation of A2A adenosine receptor (AR) with an FDA-approved agonist potently permeabilizes an in vitro primary human brain endothelial barrier (hBBB) to the passage of chemotherapeutic drugs and T cells. T cell migration under AR signaling occurs primarily by paracellular transendothelial route. Permeabilization of the hBBB is rapid, time-dependent and reversible and is mediated by morphological changes in actin-cytoskeletal reorganization induced by RhoA signaling and a potent down-regulation of Claudin-5 and VE-Cadherin. Moreover, the kinetics of BBB permeability in mice closely overlaps with the permeability kinetics of the hBBB. These data suggest that activation of A2A AR is an endogenous mechanism that may be used for CNS drug delivery in human. PMID:25262373

  1. A Genetic Algorithm Based Support Vector Machine Model for Blood-Brain Barrier Penetration Prediction

    PubMed Central

    Zhang, Daqing; Xiao, Jianfeng; Zhou, Nannan; Zheng, Mingyue; Luo, Xiaomin; Jiang, Hualiang; Chen, Kaixian

    2015-01-01

    Blood-brain barrier (BBB) is a highly complex physical barrier determining what substances are allowed to enter the brain. Support vector machine (SVM) is a kernel-based machine learning method that is widely used in QSAR study. For a successful SVM model, the kernel parameters for SVM and feature subset selection are the most important factors affecting prediction accuracy. In most studies, they are treated as two independent problems, but it has been proven that they could affect each other. We designed and implemented genetic algorithm (GA) to optimize kernel parameters and feature subset selection for SVM regression and applied it to the BBB penetration prediction. The results show that our GA/SVM model is more accurate than other currently available log BB models. Therefore, to optimize both SVM parameters and feature subset simultaneously with genetic algorithm is a better approach than other methods that treat the two problems separately. Analysis of our log BB model suggests that carboxylic acid group, polar surface area (PSA)/hydrogen-bonding ability, lipophilicity, and molecular charge play important role in BBB penetration. Among those properties relevant to BBB penetration, lipophilicity could enhance the BBB penetration while all the others are negatively correlated with BBB penetration. PMID:26504797

  2. Microfluidic organ-on-chip technology for blood-brain barrier research

    PubMed Central

    van der Helm, Marinke W; van der Meer, Andries D; Eijkel, Jan C T; van den Berg, Albert; Segerink, Loes I

    2016-01-01

    ABSTRACT Organs-on-chips are a new class of microengineered laboratory models that combine several of the advantages of current in vivo and in vitro models. In this review, we summarize the advances that have been made in the development of organ-on-chip models of the blood-brain barrier (BBBs-on-chips) and the challenges that are still ahead. The BBB is formed by specialized e3ndothelial cells and separates blood from brain tissue. It protects the brain from harmful compounds from the blood and provides homeostasis for optimal neuronal function. Studying BBB function and dysfunction is important for drug development and biomedical research. Microfluidic BBBs-on-chips enable real-time study of (human) cells in an engineered physiological microenvironment, for example incorporating small geometries and fluid flow as well as sensors. Examples of BBBs-on-chips in literature already show the potential of more realistic microenvironments and the study of organ-level functions. A key challenge in the field of BBB-on-chip development is the current lack of standardized quantification of parameters such as barrier permeability and shear stress. This limits the potential for direct comparison of the performance of different BBB-on-chip models to each other and existing models. We give recommendations for further standardization in model characterization and conclude that the rapidly emerging field of BBB-on-chip models holds great promise for further studies in BBB biology and drug development. PMID:27141422

  3. The blood-brain barrier: geriatric relevance of a critical brain-body interface.

    PubMed

    Zeevi, Neer; Pachter, Joel; McCullough, Louise D; Wolfson, Leslie; Kuchel, George A

    2010-09-01

    The blood-brain barrier (BBB) represents the interface between the brain and other body tissues. Its ability to protect the brain from harmful compounds has attracted the attention of clinicians and investigators, but far from being a simple physical barrier, the BBB is a complex, heterogeneous, and dynamic tissue. The integrated function of the cerebral microvasculature, tight junction proteins, brain microvascular endothelial cells (BMECs), cellular transport pathways, and enzymatic machinery jointly contribute to normal BBB integrity. Aging, systemic diseases, and ischemic injury can disrupt these processes, resulting in a decline in overall BBB function and integrity. Based on the published literature, this study proposes that age- and disease-related BBB alterations play a key role in diminishing the ability of older patients to recover from acute ischemic stroke. Evidence linking deficits in the cerebral microvasculature and BBB integrity to dementia, medication-related cognitive decline, white matter disease (WMD or leukoaraiosis), and related geriatric syndromes including delirium, gait disorders, and urinary incontinence is also reviewed. Priority areas for a future research agenda include strategies to improve clinicians' ability to diagnose, prevent, and manage BBB abnormalities. In future years, in vivo measures such as functional and contrast-enhanced neuroimaging will be used to evaluate BBB integrity in older adults while also assessing the effectiveness of interventions, some targeting inflammatory pathways known to disrupt the BBB, for their ability to prevent or slow the progression of these complex multifactorial geriatric syndromes. PMID:20863334

  4. Pathways for Small Molecule Delivery to the Central Nervous System Across the Blood-Brain Barrier

    PubMed Central

    Mikitsh, John L; Chacko, Ann-Marie

    2014-01-01

    The treatment of central nervous system (CNS) disease has long been difficult due to the ineffectiveness of drug delivery across the blood-brain barrier (BBB). This review summarizes important concepts of the BBB in normal versus pathophysiology and how this physical, enzymatic, and efflux barrier provides necessary protection to the CNS during drug delivery, and consequently treatment challenging. Small molecules account for the vast majority of available CNS drugs primarily due to their ability to penetrate the phospholipid membrane of the BBB by passive or carrier-mediated mechanisms. Physiochemical and biological factors relevant for designing small molecules with optimal capabilities for BBB permeability are discussed, as well as the most promising classes of transporters suitable for small-molecule drug delivery. Clinically translatable imaging methodologies for detecting and quantifying drug uptake and targeting in the brain are discussed as a means of further understanding and refining delivery parameters for both drugs and imaging probes in preclinical and clinical domains. This information can be used as a guide to design drugs with preserved drug action and better delivery profiles for improved treatment outcomes over existing therapeutic approaches. PMID:24963272

  5. MicroRNA-155 negatively affects blood-brain barrier function during neuroinflammation.

    PubMed

    Lopez-Ramirez, Miguel Alejandro; Wu, Dongsheng; Pryce, Gareth; Simpson, Julie E; Reijerkerk, Arie; King-Robson, Josh; Kay, Oliver; de Vries, Helga E; Hirst, Mark C; Sharrack, Basil; Baker, David; Male, David Kingsley; Michael, Gregory J; Romero, Ignacio Andres

    2014-06-01

    Blood-brain barrier (BBB) dysfunction is a hallmark of neurological conditions such as multiple sclerosis (MS) and stroke. However, the molecular mechanisms underlying neurovascular dysfunction during BBB breakdown remain elusive. MicroRNAs (miRNAs) have recently emerged as key regulators of pathogenic responses, although their role in central nervous system (CNS) microvascular disorders is largely unknown. We have identified miR-155 as a critical miRNA in neuroinflammation at the BBB. miR-155 is expressed at the neurovascular unit of individuals with MS and of mice with experimental autoimmune encephalomyelitis (EAE). In mice, loss of miR-155 reduced CNS extravasation of systemic tracers, both in EAE and in an acute systemic inflammation model induced by lipopolysaccharide. In cultured human brain endothelium, miR-155 was strongly and rapidly upregulated by inflammatory cytokines. miR-155 up-regulation mimicked cytokine-induced alterations in junctional organization and permeability, whereas inhibition of endogenous miR-155 partially prevented a cytokine-induced increase in permeability. Furthermore, miR-155 modulated brain endothelial barrier function by targeting not only cell-cell complex molecules such as annexin-2 and claudin-1, but also focal adhesion components such as DOCK-1 and syntenin-1. We propose that brain endothelial miR-155 is a negative regulator of BBB function that may constitute a novel therapeutic target for CNS neuroinflammatory disorders. PMID:24604078

  6. Agrin, aquaporin-4, and astrocyte polarity as an important feature of the blood-brain barrier.

    PubMed

    Wolburg, Hartwig; Noell, Susan; Wolburg-Buchholz, Karen; Mack, Andreas; Fallier-Becker, Petra

    2009-04-01

    The blood-brain barrier (BBB) does not exclusively refer to brain endothelial cells, which are the site of the barrier proper. In the past few years, it has become increasingly clear that BBB endothelial cells depend considerably on the brain microenvironment to a degree exceeding the environmental influence in other organs. The concept of the BBB has been continuously developed over the decades, culminating now in the recognition that endothelial cell function in the brain is not limited to simply mediating energy and oxygen transfer between blood and neural tissue. Endothelial cells are rather "Janus-headed beings" that are active partners of both luminal molecules and cells, as well as subendothelial cells such as pericytes, astrocytes, and neurons. In this overview, the authors present and discuss both the role of astroglial cells in managing the BBB and aspects of pathological alterations in the brain as far as the BBB is involved. After a brief introduction of the BBB that describes the structure and function of the brain capillary endothelial cells, the authors report on both the water channel protein aquaporin-4 (AQP4) in astrocytes and the extracellular matrix between astrocytes/pericytes and endothelial cells. The AQP4 has an important impact on the homeostasis in the brain parenchyma; however, the mechanistic cascade from the composition of the astrocyte membrane to the maintenance of BBB properties in the endothelial cells, including their tight junction formation, is still completely unknown. PMID:19307424

  7. Novel Models for Studying the Blood-Brain and Blood-Eye Barriers in Drosophila

    PubMed Central

    Pinsonneault, Robert L.; Mayer, Nasima; Mayer, Fahima; Tegegn, Nebiyu; Bainton, Roland J.

    2011-01-01

    Summary In species as varied as humans and flies, humoral/central nervous system barrier structures are a major obstacle to the passive penetration of small molecules including endogenous compounds, environmental toxins and drugs. In vivo measurement of blood brain physiologic function in vertebrate animal models is difficult and current ex vivo models for more rapid experimentation using, for example, cultured brain epithelial cells, only partially reconstitute the anatomy and physiology of a fully intact BBB. To address these problems, we and others continue to develop in vivo assays for studying the complex physiologic function of CNS barriers using the fruit fly Drosophila melanogaster (Dm). These methods involve the introduction of small molecule reporters of BBB physiology into the fly humoral compartment by direct injection. Since these reporters must cross the Dm BBB in order to be visible in the eye, we can directly assess genetic or chemical modulators of BBB function by monitoring retinal fluorescence. This assay has the advantage of utilizing a physiologically intact BBB in a model organism that is economical and highly amenable to genetic manipulation. In combination with other approaches outlined here, such as brain dissection and behavioral assessment, one can produce a fuller picture of BBB biology and physiology. In this chapter, we will provide detailed methods for examining BBB biology in the fly, including a Dm visual assay to screen for novel modulators of the BBB. PMID:21082381

  8. Regulation of ABC transporters blood-brain barrier: the good, the bad, and the ugly.

    PubMed

    Miller, David S

    2015-01-01

    The brain capillary endothelial cells that constitute the blood-brain barrier express multiple ABC transport proteins on the luminal, blood-facing, plasma membrane. These transporters function as ATP-driven efflux pumps for xenobiotics and endogenous metabolites. High expression of these ABC transporters at the barrier is a major obstacle to the delivery of therapeutics, including chemotherapeutics, to the CNS. Here, I review the signals that alter ABC transporter expression and transport function with an emphasis on P-glycoprotein, Mrp2, and breast cancer resistance protein (BCRP), the efflux transporters for which we have the most detailed picture of regulation. Recent work shows that transporter protein expression can be upregulated in response to inflammatory and oxidative stress, therapeutic drugs, diet, and persistent environmental pollutants; as a consequence, drug delivery to the brain is reduced (potentially bad and ugly). In contrast, basal transport activity of P-glycoprotein and BCRP can be reduced through complex signaling pathways that involve events in and on the brain capillary endothelial cells. Targeting these signaling events provides opportunities to rapidly and reversibly increase brain accumulation of drugs that are substrates for the transporters (potentially good). The clinical usefulness of targeting signaling to reduce efflux transporter activity and improve drug delivery to the CNS remains to be established. PMID:25640266

  9. Enhanced blood-brain barrier penetration and glioma therapy mediated by a new peptide modified gene delivery system.

    PubMed

    Yao, Hui; Wang, Kaiyuan; Wang, Yi; Wang, Shanshan; Li, Jianfeng; Lou, Jinning; Ye, Liya; Yan, Xueying; Lu, Weiyue; Huang, Rongqin

    2015-01-01

    Successful glioma gene therapy lays on two important factors, the therapeutic genes and efficient delivery vehicles to cross the blood-brain barrier (BBB) and reach gliomas. In this work, a new gene vector was constructed based on dendrigraft poly-l-lysines (DGL) and polyethyleneglycol (PEG), conjugated with a cell-penetrating peptide, the nucleolar translocation signal (NoLS) sequence of the LIM Kinase 2 (LIMK2) protein (LIMK2 NoLS peptide, LNP), yielding DGL-PEG-LNP. Plasmid DNA encoding inhibitor of growth 4 (ING4) was applied as the therapeutic gene. DGL-PEG-LNP/DNA nanoparticles (NPs) were monodispersed, with a mean diameter of 90.6 ± 8.9 nm. The conjugation of LNP significantly enhanced the BBB-crossing efficiency, cellular uptake and gene expression within tumor cells. Mechanism studies suggested the involvement of energy, caveolae-mediated endocytosis and macropinocytosis in cellular uptake of LNP-modified NPs. MTT results showed that no apparent cytotoxicity was observed when cells were treated with synthesized vectors. Furthermore, LNP-modified NPs mediated strongest and most intensive apoptosis on the tumor site, and the longest median survival time of glioma-bearing mice. All the results demonstrated that LNP is a kind of efficient CPPs especially for BBB-crossing application, and DGL-PEG-LNP/DNA is a potential non-viral platform for glioma gene therapy via intravenous administration. PMID:25453963

  10. Myeloperoxidase-Derived Oxidants Induce Blood-Brain Barrier Dysfunction In Vitro and In Vivo

    PubMed Central

    Üllen, Andreas; Singewald, Evelin; Konya, Viktoria; Fauler, Günter; Reicher, Helga; Nusshold, Christoph; Hammer, Astrid; Kratky, Dagmar; Heinemann, Akos; Holzer, Peter; Malle, Ernst; Sattler, Wolfgang

    2013-01-01

    Peripheral leukocytes can exacerbate brain damage by release of cytotoxic mediators that disrupt blood-brain barrier (BBB) function. One of the oxidants released by activated leukocytes is hypochlorous acid (HOCl) formed via the myeloperoxidase (MPO)-H2O2-Cl− system. In the present study we examined the role of leukocyte activation, leukocyte-derived MPO and MPO-generated oxidants on BBB function in vitro and in vivo. In a mouse model of lipopolysaccharide (LPS)-induced systemic inflammation, neutrophils that had become adherent released MPO into the cerebrovasculature. In vivo, LPS-induced BBB dysfunction was significantly lower in MPO-deficient mice as compared to wild-type littermates. Both, fMLP-activated leukocytes and the MPO-H2O2-Cl− system inflicted barrier dysfunction of primary brain microvascular endothelial cells (BMVEC) that was partially rescued with the MPO inhibitor 4-aminobenzoic acid hydrazide. BMVEC treatment with the MPO-H2O2-Cl− system or activated neutrophils resulted in the formation of plasmalogen-derived chlorinated fatty aldehydes. 2-chlorohexadecanal (2-ClHDA) severely compromised BMVEC barrier function and induced morphological alterations in tight and adherens junctions. In situ perfusion of rat brain with 2-ClHDA increased BBB permeability in vivo. 2-ClHDA potently activated the MAPK cascade at physiological concentrations. An ERK1/2 and JNK antagonist (PD098059 and SP600125, respectively) protected against 2-ClHDA-induced barrier dysfunction in vitro. The current data provide evidence that interference with the MPO pathway could protect against BBB dysfunction under (neuro)inflammatory conditions. PMID:23691142

  11. “You Shall Not Pass”—tight junctions of the blood brain barrier

    PubMed Central

    Bauer, Hans-Christian; Krizbai, István A.; Bauer, Hannelore; Traweger, Andreas

    2014-01-01

    The structure and function of the barrier layers restricting the free diffusion of substances between the central nervous system (brain and spinal cord) and the systemic circulation is of great medical interest as various pathological conditions often lead to their impairment. Excessive leakage of blood-borne molecules into the parenchyma and the concomitant fluctuations in the microenvironment following a transient breakdown of the blood-brain barrier (BBB) during ischemic/hypoxic conditions or because of an autoimmune disease are detrimental to the physiological functioning of nervous tissue. On the other hand, the treatment of neurological disorders is often hampered as only minimal amounts of therapeutic agents are able to penetrate a fully functional BBB or blood cerebrospinal fluid barrier. An in-depth understanding of the molecular machinery governing the establishment and maintenance of these barriers is necessary to develop rational strategies allowing a controlled delivery of appropriate drugs to the CNS. At the basis of such tissue barriers are intimate cell-cell contacts (zonulae occludentes, tight junctions) which are present in all polarized epithelia and endothelia. By creating a paracellular diffusion constraint TJs enable the vectorial transport across cell monolayers. More recent findings indicate that functional barriers are already established during development, protecting the fetal brain. As an understanding of the biogenesis of TJs might reveal the underlying mechanisms of barrier formation during ontogenic development numerous in vitro systems have been developed to study the assembly and disassembly of TJs. In addition, monitoring the stage-specific expression of TJ-associated proteins during development has brought much insight into the “developmental tightening” of tissue barriers. Over the last two decades a detailed molecular map of transmembrane and cytoplasmic TJ-proteins has been identified. These proteins not only form a cell

  12. Recreating blood-brain barrier physiology and structure on chip: A novel neurovascular microfluidic bioreactor

    PubMed Central

    Brown, Jacquelyn A.; Pensabene, Virginia; Markov, Dmitry A.; Allwardt, Vanessa; Neely, M. Diana; Shi, Mingjian; Britt, Clayton M.; Hoilett, Orlando S.; Yang, Qing; Brewer, Bryson M.; Samson, Philip C.; McCawley, Lisa J.; May, James M.; Webb, Donna J.; Li, Deyu; Bowman, Aaron B.; Reiserer, Ronald S.; Wikswo, John P.

    2015-01-01

    The blood-brain barrier (BBB) is a critical structure that serves as the gatekeeper between the central nervous system and the rest of the body. It is the responsibility of the BBB to facilitate the entry of required nutrients into the brain and to exclude potentially harmful compounds; however, this complex structure has remained difficult to model faithfully in vitro. Accurate in vitro models are necessary for understanding how the BBB forms and functions, as well as for evaluating drug and toxin penetration across the barrier. Many previous models have failed to support all the cell types involved in the BBB formation and/or lacked the flow-created shear forces needed for mature tight junction formation. To address these issues and to help establish a more faithful in vitro model of the BBB, we have designed and fabricated a microfluidic device that is comprised of both a vascular chamber and a brain chamber separated by a porous membrane. This design allows for cell-to-cell communication between endothelial cells, astrocytes, and pericytes and independent perfusion of both compartments separated by the membrane. This NeuroVascular Unit (NVU) represents approximately one-millionth of the human brain, and hence, has sufficient cell mass to support a breadth of analytical measurements. The NVU has been validated with both fluorescein isothiocyanate (FITC)-dextran diffusion and transendothelial electrical resistance. The NVU has enabled in vitro modeling of the BBB using all human cell types and sampling effluent from both sides of the barrier. PMID:26576206

  13. Estrogen protects the blood-brain barrier from inflammation-induced disruption and increased lymphocyte trafficking.

    PubMed

    Maggioli, E; McArthur, S; Mauro, C; Kieswich, J; Kusters, D H M; Reutelingsperger, C P M; Yaqoob, M; Solito, E

    2016-01-01

    Sex differences have been widely reported in neuroinflammatory disorders, focusing on the contributory role of estrogen. The microvascular endothelium of the brain is a critical component of the blood-brain barrier (BBB) and it is recognized as a major interface for communication between the periphery and the brain. As such, the cerebral capillary endothelium represents an important target for the peripheral estrogen neuroprotective functions, leading us to hypothesize that estrogen can limit BBB breakdown following the onset of peripheral inflammation. Comparison of male and female murine responses to peripheral LPS challenge revealed a short-term inflammation-induced deficit in BBB integrity in males that was not apparent in young females, but was notable in older, reproductively senescent females. Importantly, ovariectomy and hence estrogen loss recapitulated an aged phenotype in young females, which was reversible upon estradiol replacement. Using a well-established model of human cerebrovascular endothelial cells we investigated the effects of estradiol upon key barrier features, namely paracellular permeability, transendothelial electrical resistance, tight junction integrity and lymphocyte transmigration under basal and inflammatory conditions, modeled by treatment with TNFα and IFNγ. In all cases estradiol prevented inflammation-induced defects in barrier function, action mediated in large part through up-regulation of the central coordinator of tight junction integrity, annexin A1. The key role of this protein was then further confirmed in studies of human or murine annexin A1 genetic ablation models. Together, our data provide novel mechanisms for the protective effects of estrogen, and enhance our understanding of the beneficial role it plays in neurovascular/neuroimmune disease. PMID:26321046

  14. Effects of acute hyperosmolality on blood-brain barrier function in ovine fetuses and lambs.

    PubMed

    Stonestreet, Barbara S; Sadowska, Grazyna B; Leeman, Joanne; Hanumara, R Choudary; Petersson, Katherine H; Patlak, Clifford S

    2006-10-01

    We examined the effects of hyperosmolality on blood-brain barrier (BBB) permeability during development to test the vulnerability of the immature barrier to stress. The BBB response to hyperosmolality was quantified using the blood-to-brain transfer constant (Ki) with alpha-aminoisobutyric acid in fetuses at 60% and 90% gestation, premature, newborn, and older lambs. Ki plotted against osmolality increased as a function of increases in osmolality in all groups and brain regions. The relationship was described (P < 0.05) by a segmented regression model. At lower osmolalities, changes in Ki were minimal, but after a break point (threshold) was reached, the increase (P < 0.05) was linear. We examined the responses of Ki to hyperosmolality within each brain region by comparing the thresholds and slopes of the second regression segment. Lower thresholds and higher slopes imply greater vulnerability to hyperosmolality in the younger groups. Thresholds increased (P < 0.05) with development in the thalamus, superior colliculus, pons, and spinal cord, and slopes of the second regression segment decreased (P < 0.05) in the cerebellum, hippocampus, inferior colliculus, medulla, and spinal cord. BBB resistance to hyperosmolality increased (P < 0.05) with development in most brain regions. The pattern of the Ki plotted against osmolality was (P < 0.05) heterogenous among brain regions in fetuses and premature and newborn lambs, but not in older lambs. We conclude that 1) BBB permeability increased as a function of changes in osmolality, 2) the barrier becomes more resistant to hyperosmolality during development, and 3) the permeability response to hyperosmolality is heterogenous among brain regions in fetuses and premature and newborn lambs. PMID:16690764

  15. The Drosophila surface glia transcriptome: evolutionary conserved blood-brain barrier processes

    PubMed Central

    DeSalvo, Michael K.; Hindle, Samantha J.; Rusan, Zeid M.; Orng, Souvinh; Eddison, Mark; Halliwill, Kyle; Bainton, Roland J.

    2014-01-01

    Central nervous system (CNS) function is dependent on the stringent regulation of metabolites, drugs, cells, and pathogens exposed to the CNS space. Cellular blood-brain barrier (BBB) structures are highly specific checkpoints governing entry and exit of all small molecules to and from the brain interstitial space, but the precise mechanisms that regulate the BBB are not well understood. In addition, the BBB has long been a challenging obstacle to the pharmacologic treatment of CNS diseases; thus model systems that can parse the functions of the BBB are highly desirable. In this study, we sought to define the transcriptome of the adult Drosophila melanogaster BBB by isolating the BBB surface glia with fluorescence activated cell sorting (FACS) and profiling their gene expression with microarrays. By comparing the transcriptome of these surface glia to that of all brain glia, brain neurons, and whole brains, we present a catalog of transcripts that are selectively enriched at the Drosophila BBB. We found that the fly surface glia show high expression of many ATP-binding cassette (ABC) and solute carrier (SLC) transporters, cell adhesion molecules, metabolic enzymes, signaling molecules, and components of xenobiotic metabolism pathways. Using gene sequence-based alignments, we compare the Drosophila and Murine BBB transcriptomes and discover many shared chemoprotective and small molecule control pathways, thus affirming the relevance of invertebrate models for studying evolutionary conserved BBB properties. The Drosophila BBB transcriptome is valuable to vertebrate and insect biologists alike as a resource for studying proteins underlying diffusion barrier development and maintenance, glial biology, and regulation of drug transport at tissue barriers. PMID:25426014

  16. The pivotal role of astrocytes in an in vitro stroke model of the blood-brain barrier

    PubMed Central

    Neuhaus, Winfried; Gaiser, Fabian; Mahringer, Anne; Franz, Jonas; Riethmüller, Christoph; Förster, Carola

    2014-01-01

    Stabilization of the blood-brain barrier during and after stroke can lead to less adverse outcome. For elucidation of underlying mechanisms and development of novel therapeutic strategies validated in vitro disease models of the blood-brain barrier could be very helpful. To mimic in vitro stroke conditions we have established a blood-brain barrier in vitro model based on mouse cell line cerebEND and applied oxygen/glucose deprivation (OGD). The role of astrocytes in this disease model was investigated by using cell line C6. Transwell studies pointed out that addition of astrocytes during OGD increased the barrier damage significantly in comparison to the endothelial monoculture shown by changes of transendothelial electrical resistance as well as fluorescein permeability data. Analysis on mRNA and protein levels by qPCR, western blotting and immunofluorescence microscopy of tight junction molecules claudin-3,-5,-12, occludin and ZO-1 revealed that their regulation and localisation is associated with the functional barrier breakdown. Furthermore, soluble factors of astrocytes, OGD and their combination were able to induce changes of functionality and expression of ABC-transporters Abcb1a (P-gp), Abcg2 (bcrp), and Abcc4 (mrp4). Moreover, the expression of proteases (matrixmetalloproteinases MMP-2, MMP-3, MMP-9, and t-PA) as well as of their endogenous inhibitors (TIMP-1, TIMP-3, PAI-1) was altered by astrocyte factors and OGD which resulted in significant changes of total MMP and t-PA activity. Morphological rearrangements induced by OGD and treatment with astrocyte factors were confirmed at a nanometer scale using atomic force microscopy. In conclusion, astrocytes play a major role in blood-brain barrier breakdown during OGD in vitro. PMID:25389390

  17. Delivery of dopamine transporter tracer (PE2I) through blood brain barrier with ultrasound and microbubbles

    NASA Astrophysics Data System (ADS)

    Serrière, Sophie; Escoffre, Jean-Michel; Bodard, Sylvie; Novell, Anthony; Vergote, Jackie; Vercouillie, Johnny; Thiéry, Jean-Claude; Chalon, Sylvie; Bouakaz, Ayache

    2012-10-01

    The blood-brain barrier plays a major role in controlling the delivery of therapeutic and imaging agents to the brain. The aim of this study was to investigate the use of ultrasound and microbubbles to increase its delivery through the BBB and by determining the optimal experimental conditions that achieve a transient and safe BBB disruption. First, we established the ultrasound conditions that achieved a transient BBB disruption in rats using a non-permeant marker, Evans blue. Hence SonoVue® (450 μL/kg) and Evans blue (100 mg/kg) were intravenously administered. BBB leakage was obtained using ultrasound insonation through the rat skull at 1.6 MPa, PRF 1 Hz, duty cycle 12%, burst 10 ms during 120 sec. BBB disruption was observed in all treated animals (N=4) by histological analysis. The same experimental conditions were applied to enhance brain uptake of PE2I. Biological samples were analyzed using a scintillation counter apparatus. The results showed 50% and 20% increase of 125I-PE2I uptake in the striatum and cerebral cortex, respectively, in the treated rats (N=5) versus control (N=4). Similar enhancements were observed using SonoVue® at half concentration. This innovative method provides a great potential for intracerebral delivery of molecular ligands that could be used for the therapy of brain diseases.

  18. Reversible Opening of the Blood-Brain Barrier by Anti-Bacterial Antibodies

    NASA Astrophysics Data System (ADS)

    Tuomanen, Elaine I.; Prasad, Sudha M.; George, Jonathan S.; Hoepelman, Andy I. M.; Ibsen, Per; Heron, Iver; Starzyk, Ruth M.

    1993-08-01

    The leukocyte adhesion molecule CR3 (CD11b/CD18, Mac-1) promotes leukocyte transmigration into tissues by engaging an unknown cognate ligand on the surface of vascular endothelial cells. Filamentous hemagglutinin (FHA), an adhesin of the bacterium Bordetella pertussis, binds to CR3. We hypothesized that FHA mimics the native ligand for the CR3 integrin on endothelial cells and predicted that anti-FHA antibodies should bind to endothelial cells, interfere with leukocyte recruitment, and induce endothelial permeability. Anti-FHA monoclonal antibodies bound to cerebral microvessels in sections from human brain and upon intravenous injection into rabbits. Antibody binding correlated with the ability to recognize two polypeptides in extracts of human cerebral vessels that were also bound by CD18. In vivo, antibody binding not only interfered with transmigration of leukocytes into cerebrospinal fluid but also induced a dose-dependent reversible increase in blood-brain barrier permeability sufficient to improve delivery of intravenously administered therapeutic agents to brain parenchyma.

  19. Transporter protein and drug-conjugated gold nanoparticles capable of bypassing the blood-brain barrier.

    PubMed

    Zhang, Yanhua; Walker, Janelle Buttry; Minic, Zeljka; Liu, Fangchao; Goshgarian, Harry; Mao, Guangzhao

    2016-01-01

    Drug delivery to the central nervous system (CNS) is challenging due to the inability of many drugs to cross the blood-brain barrier (BBB). Here, we show that wheat germ agglutinin horse radish peroxidase (WGA-HRP) chemically conjugated to gold nanoparticles (AuNPs) can be transported to the spinal cord and brainstem following intramuscular injection into the diaphragm of rats. We synthesized and determined the size and chemical composition of a three-part nanoconjugate consisting of WGA-HRP, AuNPs, and drugs for the treatment of diaphragm paralysis associated with high cervical spinal cord injury (SCI). Upon injection into the diaphragm muscle of rats, we show that the nanoconjugate is capable of delivering the drug at a much lower dose than the unconjugated drug injected systemically to effectively induce respiratory recovery in rats following SCI. This study not only demonstrates a promising strategy to deliver drugs to the CNS bypassing the BBB but also contributes a potential nanotherapy for the treatment of respiratory muscle paralysis resulted from cervical SCI. PMID:27180729

  20. Blood-Brain Barrier Dysfunction and Cerebral Small Vessel Disease (Arteriolosclerosis) in Brains of Older People

    PubMed Central

    Khoong, Cheryl H.L.; Poon, Wayne; Esiri, Margaret M.; Markus, Hugh S.; Hainsworth, Atticus H.

    2014-01-01

    The blood-brain barrier (BBB) protects brain tissue from potentially harmful plasma components. Small vessel disease ([SVD], arteriolosclerosis) is common in the brains of older people and is associated with lacunar infarcts, leukoaraiosis and vascular dementia. To determine whether plasma extravasation is associated with SVD, we immunolabeled the plasma proteins fibrinogen and IgG, which are assumed to reflect BBB dysfunction, in deep grey matter (anterior caudate-putamen, [DGM]) and deep subcortical white matter (DWM) in the brains of a well-characterized patient cohort with minimal Alzheimer disease pathology (Braak stage 0-II) (n = 84; age ≥65 years). Morphometric measures of fibrinogen labeling were compared between people with neuropathologically defined SVD and aged control subjects. Parenchymal cellular labeling with fibrinogen and IgG was detectable in DGM and DWM in many subjects (>70%). Quantitative measures of fibrinogen were not associated with SVD in DGM or DWM; SVD severity was correlated between DGM and DWM (p < 0.0001). Fibrinogen in DGM showed a modest association with a history of hypertension; DWM fibrinogen was associated with dementia and cerebral amyloid angiopathy (all p < 0.05). In DWM, SVD was associated with leukoaraiosis identified in life (p < 0.05), but fibrinogen was not. Our data suggest that in aged brains plasma extravasation and hence local BBB dysfunction is common but do not support an association with SVD. PMID:25289893

  1. Addressing safety liabilities of TfR bispecific antibodies that cross the blood-brain barrier.

    PubMed

    Couch, Jessica A; Yu, Y Joy; Zhang, Yin; Tarrant, Jacqueline M; Fuji, Reina N; Meilandt, William J; Solanoy, Hilda; Tong, Raymond K; Hoyte, Kwame; Luk, Wilman; Lu, Yanmei; Gadkar, Kapil; Prabhu, Saileta; Ordonia, Benjamin A; Nguyen, Quyen; Lin, Yuwen; Lin, Zhonghua; Balazs, Mercedesz; Scearce-Levie, Kimberly; Ernst, James A; Dennis, Mark S; Watts, Ryan J

    2013-05-01

    Bispecific antibodies using the transferrin receptor (TfR) have shown promise for boosting antibody uptake in brain. Nevertheless, there are limited data on the therapeutic properties including safety liabilities that will enable successful development of TfR-based therapeutics. We evaluate TfR/BACE1 bispecific antibody variants in mouse and show that reducing TfR binding affinity improves not only brain uptake but also peripheral exposure and the safety profile of these antibodies. We identify and seek to address liabilities of targeting TfR with antibodies, namely, acute clinical signs and decreased circulating reticulocytes observed after dosing. By eliminating Fc effector function, we ameliorated the acute clinical signs and partially rescued a reduction in reticulocytes. Furthermore, we show that complement mediates a residual decrease in reticulocytes observed after Fc effector function is eliminated. These data raise important safety concerns and potential mitigation strategies for the development of TfR-based therapies that are designed to cross the blood-brain barrier. PMID:23636093

  2. Laminin receptor initiates bacterial contact with the blood brain barrier in experimental meningitis models

    PubMed Central

    Orihuela, Carlos J.; Mahdavi, Jafar; Thornton, Justin; Mann, Beth; Wooldridge, Karl G.; Abouseada, Noha; Oldfield, Neil J.; Self, Tim; Ala’Aldeen, Dlawer A.A.; Tuomanen, Elaine I.

    2009-01-01

    A diverse array of infectious agents, including prions and certain neurotropic viruses, bind to the laminin receptor (LR), and this determines tropism to the CNS. Bacterial meningitis in childhood is almost exclusively caused by the respiratory tract pathogens Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae, but the mechanism by which they initiate contact with the vascular endothelium of the blood brain barrier (BBB) is unknown. We hypothesized that an interaction with LR might underlie their CNS tropism. Using affinity chromatography, coimmunoprecipitation, retagging, and in vivo imaging approaches, we identified 37/67-kDa LR as a common receptor for all 3 bacteria on the surface of rodent and human brain microvascular endothelial cells. Mutagenesis studies indicated that the corresponding bacterial LR-binding adhesins were pneumococcal CbpA, meningococcal PilQ and PorA, and OmpP2 of H. influenzae. The results of competitive binding experiments suggest that a common adhesin recognition site is present in the carboxyl terminus of LR. Together, these findings suggest that disruption or modulation of the interaction of bacterial adhesins with LR might engender unexpectedly broad protection against bacterial meningitis and may provide a therapeutic target for the prevention and treatment of disease. PMID:19436113

  3. Blood-Brain Barrier Dysfunction as a Hallmark Pathology in Chronic Traumatic Encephalopathy.

    PubMed

    Doherty, Colin P; O'Keefe, Eoin; Wallace, Eugene; Loftus, Teresa; Keaney, James; Kealy, John; Humphries, Marian M; Molloy, Michael G; Meaney, James F; Farrell, Michael; Campbell, Matthew

    2016-07-01

    Chronic traumatic encephalopathy (CTE) is a neurodegenerative condition associated with repetitive mild traumatic brain injury. In recent years, attention has focused on emerging evidence linking the development of CTE to concussive injuries in athletes and military personnel; however, the underlying molecular pathobiology of CTE remains unclear. Here, we provide evidence that the blood-brain barrier (BBB) is disrupted in regions of dense perivascular p-Tau accumulation in a case of CTE. Immunoreactivity patterns of the BBB-associated tight junction components claudin-5 and zonula occludens-1 were markedly discontinuous or absent in regions of perivascular p-Tau deposition; there was also immunohistochemical evidence of a BBB in these foci. Because the patient was diagnosed premortem clinically as having progressive supranuclear palsy (PSP), we also compromised that the CTE alterations appear to be distinct from those in the brain of a patient with PSP. This report represents the first description of BBB dysfunction in a pathologically proven CTE case and suggests a vascular component in the postconcussion cascade of events that may ultimately lead to development of a progressive degenerative disorder. BBB dysfunction may represent a correlate of neural dysfunction in live subjects suspected of being at risk for development of CTE. PMID:27245243

  4. Three-Dimensional Blood-Brain Barrier Model for in vitro Studies of Neurovascular Pathology.

    PubMed

    Cho, Hansang; Seo, Ji Hae; Wong, Keith H K; Terasaki, Yasukazu; Park, Joseph; Bong, Kiwan; Arai, Ken; Lo, Eng H; Irimia, Daniel

    2015-01-01

    Blood-brain barrier (BBB) pathology leads to neurovascular disorders and is an important target for therapies. However, the study of BBB pathology is difficult in the absence of models that are simple and relevant. In vivo animal models are highly relevant, however they are hampered by complex, multi-cellular interactions that are difficult to decouple. In vitro models of BBB are simpler, however they have limited functionality and relevance to disease processes. To address these limitations, we developed a 3-dimensional (3D) model of BBB on a microfluidic platform. We verified the tightness of the BBB by showing its ability to reduce the leakage of dyes and to block the transmigration of immune cells towards chemoattractants. Moreover, we verified the localization at endothelial cell boundaries of ZO-1 and VE-Cadherin, two components of tight and adherens junctions. To validate the functionality of the BBB model, we probed its disruption by neuro-inflammation mediators and ischemic conditions and measured the protective function of antioxidant and ROCK-inhibitor treatments. Overall, our 3D BBB model provides a robust platform, adequate for detailed functional studies of BBB and for the screening of BBB-targeting drugs in neurological diseases. PMID:26503597

  5. Blood-Brain Barrier Impairment in an Animal Model of MPS III B

    PubMed Central

    Garbuzova-Davis, Svitlana; Louis, Michael K.; Haller, Edward M.; Derasari, Hiranya M.; Rawls, Ashley E.; Sanberg, Paul R.

    2011-01-01

    Background Sanfilippo syndrome type B (MPS III B) is caused by a deficiency of α-N-acetylglucosaminidase enzyme, leading to accumulation of heparan sulfate within lysosomes and eventual progressive cerebral and systemic multiple organ abnormalities. However, little is known about the competence of the blood-brain barrier (BBB) in MPS III B. BBB dysfunction in this devastating disorder could contribute to neuropathological disease manifestations. Methodology/Principal Findings In the present study, we investigated structural (electron microscope) and functional (vascular leakage) integrity of the BBB in a mouse model of MPS III B at different stages of disease, focusing on brain structures known to experience neuropathological changes. Major findings of our study were: (1) endothelial cell damage in capillary ultrastructure, compromising the BBB and resulting in vascular leakage, (2) formation of numerous large vacuoles in endothelial cells and perivascular cells (pericytes and perivascular macrophages) in the large majority of vessels, (3) edematous space around microvessels, (4) microaneurysm adjacent to a ruptured endothelium, (6) Evans Blue and albumin microvascular leakage in various brain structures, (7) GM3 ganglioside accumulation in endothelium of the brain microvasculature. Conclusions/Significance These new findings of BBB structural and function impairment in MPS III B mice even at early disease stage may have implications for disease pathogenesis and should be considered in current and future development of treatments for MPS III B. PMID:21408219

  6. Glucose transporter of the human brain and blood-brain barrier

    SciTech Connect

    Kalaria, R.N.; Gravina, S.A.; Schmidley, J.W.; Perry, G.; Harik, S.I.

    1988-12-01

    We identified and characterized the glucose transporter in the human cerebral cortex, cerebral microvessels, and choroid plexus by specific D-glucose-displaceable (3H)cytochalasin B binding. The binding was saturable, with a dissociation constant less than 1 microM. Maximal binding capacity was approximately 7 pmol/mg protein in the cerebral cortex, approximately 42 pmol/mg protein in brain microvessels, and approximately 27 pmol/mg protein in the choroid plexus. Several hexoses displaced specific (3H)cytochalasin B binding to microvessels in a rank-order that correlated well with their known ability to cross the blood-brain barrier; the only exception was 2-deoxy-D-glucose, which had much higher affinity for the glucose transporter than the natural substrate, D-glucose. Irreversible photoaffinity labeling of the glucose transporter of microvessels with (3H)cytochalasin B, followed by solubilization and polyacrylamide gel electrophoresis, labeled a protein band with an average molecular weight of approximately 55,000. Monoclonal and polyclonal antibodies specific to the human erythrocyte glucose transporter immunocytochemically stained brain blood vessels and the few trapped erythrocytes in situ, with minimal staining of the neuropil. In the choroid plexus, blood vessels did not stain, but the epithelium reacted positively. We conclude that human brain microvessels are richly endowed with a glucose transport moiety similar in molecular weight and antigenic characteristics to that of human erythrocytes and brain microvessels of other mammalian species.

  7. Aluminum permeation of the blood-brain barrier occurs primarily across brain capillaries

    SciTech Connect

    Allen, D.D.; Yokel, R.A. )

    1991-03-11

    Aluminum has been demonstrated to be neurotoxic and has been implicated in several neurobehavioral disorders. The primary site(s) and mechanism(s) of Al flux across the blood-brain barrier (BBB) have not been elucidated. Aluminum (Al) permeation of the BBB was assessed in male Sprague-Dawley rats. Utilizing the in vivo microdialysis technique, unbound extracellular Al concentrations were ascertained at the two potential sites of flux across the BBB; the choroid plexus and brain capillaries. Microdialysis probes were implanted in the lateral ventricle and in the frontal cortex to elucidate flux across the choroid plexus and brain capillaries, respectively. A microdialysis probe was also implanted in the jugular vein to reveal blood Al concentrations. Aluminum citrate was administered via the femoral vein. Peak frontal cortex and blood Al concentration were seen within the first two 5 minute sampling periods. When concentrations were measurable for lateral ventricle, the peak concentrations were also seen within the first two 5 minute sampling periods. Area under the curve (AUC) (concentrations vs. time to last sample time point) values were calculated using RSTRIP. Brain and cerebrospinal fluid AUCs were divided by blood AUC within animal to calculate tissue/blood ratios (TBRs). Frontal cortex TBRs were significantly higher than those calculated for lateral ventricle. The results indicate that the primary site of Al flux across the BBB occurs at brain capillaries.

  8. Unilateral Opening of Rat Blood-Brain Barrier Assisted by Diagnostic Ultrasound Targeted Microbubbles Destruction.

    PubMed

    Xu, Yali; Cui, Hai; Zhu, Qiong; Hua, Xing; Xia, Hongmei; Tan, Kaibin; Gao, Yunhua; Zhao, Jing; Liu, Zheng

    2016-01-01

    Objective. Blood-brain barrier (BBB) is a key obstacle that prevents the medication from blood to the brain. Microbubble-enhanced cavitation by focused ultrasound can open the BBB and proves to be valuable in the brain drug delivery. The study aimed to explore the feasibility, efficacy, and safety of unilateral opening of BBB using diagnostic ultrasound targeted microbubbles destruction in rats. Methods. A transtemporal bone irradiation of diagnostic ultrasound and intravenous injection of lipid-coated microbubbles were performed at unilateral hemisphere. Pathological changes were monitored. Evans Blue extravasation grades, extraction from brain tissue, and fluorescence optical density were quantified. Lanthanum nitrate was traced by transmission electron microscopy. Results. After diagnostic ultrasound mediated microbubbles destruction, Evans Blue extravasation and fluorescence integrated optical density were significantly higher in the irradiated hemisphere than the contralateral side (all p < 0.01). Erythrocytes extravasations were demonstrated in the ultrasound-exposed hemisphere (4 ± 1, grade 2) while being invisible in the control side. Lanthanum nitrate tracers leaked through interendothelial cleft and spread to the nerve fiber existed in the irradiation side. Conclusions. Transtemporal bone irradiation under DUS mediated microbubble destruction provides us with a more accessible, safer, and higher selective BBB opening approach in rats, which is advantageous in brain targeted drugs delivery. PMID:27579317

  9. Three-Dimensional Blood-Brain Barrier Model for in vitro Studies of Neurovascular Pathology

    NASA Astrophysics Data System (ADS)

    Cho, Hansang; Seo, Ji Hae; Wong, Keith H. K.; Terasaki, Yasukazu; Park, Joseph; Bong, Kiwan; Arai, Ken; Lo, Eng H.; Irimia, Daniel

    2015-10-01

    Blood-brain barrier (BBB) pathology leads to neurovascular disorders and is an important target for therapies. However, the study of BBB pathology is difficult in the absence of models that are simple and relevant. In vivo animal models are highly relevant, however they are hampered by complex, multi-cellular interactions that are difficult to decouple. In vitro models of BBB are simpler, however they have limited functionality and relevance to disease processes. To address these limitations, we developed a 3-dimensional (3D) model of BBB on a microfluidic platform. We verified the tightness of the BBB by showing its ability to reduce the leakage of dyes and to block the transmigration of immune cells towards chemoattractants. Moreover, we verified the localization at endothelial cell boundaries of ZO-1 and VE-Cadherin, two components of tight and adherens junctions. To validate the functionality of the BBB model, we probed its disruption by neuro-inflammation mediators and ischemic conditions and measured the protective function of antioxidant and ROCK-inhibitor treatments. Overall, our 3D BBB model provides a robust platform, adequate for detailed functional studies of BBB and for the screening of BBB-targeting drugs in neurological diseases.

  10. Transport of nanoparticles through the blood-brain barrier for imaging and therapeutic applications

    NASA Astrophysics Data System (ADS)

    Shilo, Malka; Motiei, Menachem; Hana, Panet; Popovtzer, Rachela

    2014-01-01

    A critical problem in the treatment of neurodegenerative disorders and diseases, such as Alzheimer's and Parkinson's, is the incapability to overcome the restrictive mechanism of the blood-brain barrier (BBB) and to deliver important therapeutic agents to the brain. During the last decade, nanoparticles have gained attention as promising drug delivery agents that can transport across the BBB and increase the uptake of appropriate drugs in the brain. In this study we have developed insulin-targeted gold nanoparticles (INS-GNPs) and investigated quantitatively the amount of INS-GNPs that cross the BBB by the receptor-mediated endocytosis process. For this purpose, INS-GNPs and control GNPs were injected into the tail vein of male BALB/c mice. Major organs were then extracted and a blood sample was taken from the mice, and thereafter analyzed for gold content by flame atomic absorption spectroscopy. Results show that two hours post-intravenous injection, the amount of INS-GNPs found in mouse brains is over 5 times greater than that of the control, untargeted GNPs. Results of further experimentation on a rat model show that INS-GNPs can also serve as CT contrast agents to highlight specific brain regions in which they accumulate. Due to the fact that they can overcome the restrictive mechanism of the BBB, this approach could be a potentially valuable tool, helping to confront the great challenge of delivering important imaging and therapeutic agents to the brain for detection and treatment of neurodegenerative disorders and diseases.

  11. Aging and sex influence the permeability of the blood-brain barrier in the rat

    SciTech Connect

    Saija, A.; Princi, P.; D'Amico, N.; De Pasquale, R.; Costa, G.

    1990-01-01

    The aim of the present study was to investigate the existence of aging- and sex-related alterations in the permeability of the blood-brain barrier (BBB) in the rat, by calculating a unidirectional blood-to-brain transfer constant (Ki) for the circulating tracer ({sup 14}C)-{alpha}-aminoisobutyric acid. The authors observed that: (a) the permeability of the BBB significantly increased within the frontal and temporo-parietal cortex, hypothalamus and cerebellum in 28-30 week old rats, in comparison with younger animals; (b) in several brain areas of female intact rats higher Ki values (even though not significantly different) were calculated at oestrus than at proestrus; (c) in 1-week ovariectomized rats there was a marked increase of Ki values at the level of the frontal, temporo-parietal and occipital cortex, cerebellum and brain-stem. One can speculate that aging and sex-related alterations in thee permeability of the BBB reflect respectively changes in brain neurochemical system activity and in plasma steroid hormone levels.

  12. Correlation between astrocyte activity and recovery from blood-brain barrier breakdown caused by brain injury.

    PubMed

    Ikeshima-Kataoka, Hiroko; Yasui, Masato

    2016-08-17

    Glial activation is associated with cell proliferation and upregulation of astrocyte marker expression following traumatic injury in the brain. However, the biological significance of these processes remains unclear. In the present study, astrocyte activation was investigated in a murine brain injury model. Brain injury induces blood-brain barrier (BBB) breakdown and immunoglobulin G (IgG) leak into the brain parenchyma. The recovery of BBB breakdown was evaluated by analyzing immunofluorescent staining with mouse IgG antibody. IgG leakage was greatest at 1 day after stab wound injury and decreased thereafter, and almost diminished after 7 days. Bromodeoxy uridine incorporation was used, and astrocyte proliferation rates were examined by coimmunostaining with anti-bromodeoxy uridine and anti-glial fibrillary acid protein antibodies. Consistent with IgG leakage assays, astrocyte activation was the highest at day 3 and decreased after 7 days. Moreover, in reverse transcriptase-quantitative-PCR experiments, genes associated with BBB integrity were downregulated immediately after BBB breakdown and recovered to basal expression levels within 7 days. These data indicated that astrocyte activation correlated with BBB recovery from breakdown following brain injury. PMID:27362437

  13. Bacterial induction of Snail1 contributes to blood-brain barrier disruption

    PubMed Central

    Kim, Brandon J.; Hancock, Bryan M.; Bermudez, Andres; Cid, Natasha Del; Reyes, Efren; van Sorge, Nina M.; Lauth, Xavier; Smurthwaite, Cameron A.; Hilton, Brett J.; Stotland, Aleksandr; Banerjee, Anirban; Buchanan, John; Wolkowicz, Roland; Traver, David; Doran, Kelly S.

    2015-01-01

    Bacterial meningitis is a serious infection of the CNS that results when blood-borne bacteria are able to cross the blood-brain barrier (BBB). Group B Streptococcus (GBS) is the leading cause of neonatal meningitis; however, the molecular mechanisms that regulate bacterial BBB disruption and penetration are not well understood. Here, we found that infection of human brain microvascular endothelial cells (hBMECs) with GBS and other meningeal pathogens results in the induction of host transcriptional repressor Snail1, which impedes expression of tight junction genes. Moreover, GBS infection also induced Snail1 expression in murine and zebrafish models. Tight junction components ZO-1, claudin 5, and occludin were decreased at both the transcript and protein levels in hBMECs following GBS infection, and this repression was dependent on Snail1 induction. Bacteria-independent Snail1 expression was sufficient to facilitate tight junction disruption, promoting BBB permeability to allow bacterial passage. GBS induction of Snail1 expression was dependent on the ERK1/2/MAPK signaling cascade and bacterial cell wall components. Finally, overexpression of a dominant-negative Snail1 homolog in zebrafish elevated transcription of tight junction protein–encoding genes and increased zebrafish survival in response to GBS challenge. Taken together, our data support a Snail1-dependent mechanism of BBB disruption and penetration by meningeal pathogens. PMID:25961453

  14. Matrix Metalloproteinases and Blood-Brain Barrier Disruption in Acute Ischemic Stroke

    PubMed Central

    Lakhan, Shaheen E.; Kirchgessner, Annette; Tepper, Deborah; Leonard, Aidan

    2013-01-01

    Ischemic stroke continues to be one of the most challenging diseases in translational neurology. Tissue plasminogen activator (tPA) remains the only approved treatment for acute ischemic stroke, but its use is limited to the first hours after stroke onset due to an increased risk of hemorrhagic transformation over time resulting in enhanced brain injury. In this review we discuss the role of matrix metalloproteinases (MMPs) in blood-brain barrier (BBB) disruption as a consequence of ischemic stroke. MMP-9 in particular appears to play an important role in tPA-associated hemorrhagic complications. Reactive oxygen species can enhance the effects of tPA on MMP activation through the loss of caveolin-1 (cav-1), a protein encoded in the cav-1 gene that serves as a critical determinant of BBB permeability. This review provides an overview of MMPs’ role in BBB breakdown during acute ischemic stroke. The possible role of MMPs in combination treatment of acute ischemic stroke is also examined. PMID:23565108

  15. Nafamostat mesilate protects against acute cerebral ischemia via blood-brain barrier protection.

    PubMed

    Wang, Jing; Li, Chenhui; Chen, Tao; Fang, Yinquan; Shi, Xinzhong; Pang, Tao; Zhang, Luyong; Liao, Hong

    2016-06-01

    Serine proteases, such as thrombin, are contributors to the disruption of the blood-brain barrier (BBB) and exacerbate brain damage during ischemic stroke, for which the current clinical therapy remains unsatisfactory. However, the effect of nafamostat mesilate (NM), a synthetic serine protease inhibitor, on BBB disruption following cerebral ischemia is unknown. Here, we investigated the in vivo effect of NM on BBB integrity in rats subjected to transient middle cerebral artery occlusion (MCAO) and explored the possible mechanism in an in vitro BBB model comprising rat brain microvascular endothelial cells and astrocytes after oxygen and glucose deprivation (OGD) in the presence of thrombin. The results showed that NM treatment remarkably attenuated transient MCAO-induced brain infarcts, brain oedema and motor dysfunction in addition to BBB disruption, which might be related to changes in tight junction protein expression and localization. Meanwhile, NM preserved BBB integrity and alleviated the changes in tight junction protein expression and localization and cytoskeleton rearrangement in rat brain microvascular endothelial cells via thrombin inhibition. Our findings suggest that NM treatment can preserve BBB integrity through the inhibition of thrombin, which might be correlated with the regulation of PKCα/RhoA/MLC2 pathway components. PMID:26861077

  16. Nanoparticle-mediated brain drug delivery: Overcoming blood-brain barrier to treat neurodegenerative diseases.

    PubMed

    Saraiva, Cláudia; Praça, Catarina; Ferreira, Raquel; Santos, Tiago; Ferreira, Lino; Bernardino, Liliana

    2016-08-10

    The blood-brain barrier (BBB) is a vital boundary between neural tissue and circulating blood. The BBB's unique and protective features control brain homeostasis as well as ion and molecule movement. Failure in maintaining any of these components results in the breakdown of this specialized multicellular structure and consequently promotes neuroinflammation and neurodegeneration. In several high incidence pathologies such as stroke, Alzheimer's (AD) and Parkinson's disease (PD) the BBB is impaired. However, even a damaged and more permeable BBB can pose serious challenges to drug delivery into the brain. The use of nanoparticle (NP) formulations able to encapsulate molecules with therapeutic value, while targeting specific transport processes in the brain vasculature, may enhance drug transport through the BBB in neurodegenerative/ischemic disorders and target relevant regions in the brain for regenerative processes. In this review, we will discuss BBB composition and characteristics and how these features are altered in pathology, namely in stroke, AD and PD. Additionally, factors influencing an efficient intravenous delivery of polymeric and inorganic NPs into the brain as well as NP-related delivery systems with the most promising functional outcomes will also be discussed. PMID:27208862

  17. 'À la carte' peptide shuttles: tools to increase their passage across the blood-brain barrier.

    PubMed

    Malakoutikhah, Morteza; Guixer, Bernat; Arranz-Gibert, Pol; Teixidó, Meritxell; Giralt, Ernest

    2014-07-01

    Noninvasive methods for efficient drug delivery to the brain is an unmet need. Molecular access to the brain is regulated by the blood-brain barrier (BBB) established by the endothelial cells of brain vessels. Passive diffusion is one of the main mechanisms that organic compounds use to travel through these endothelial cells. This passage across the BBB is determined mainly by certain physicochemical properties of the molecule such as lipophilicity, size, and the presence of hydrogen bond donors and acceptors. One emerging strategy to facilitate the passage of organic compounds across the BBB is the use of peptide shuttles.1 In using this approach the permeability in front the BBB is, clearly, determined by the combined physicochemical properties of both the cargo and the shuttle. Herein we report the synthesis of a series of variations of one of the more efficient peptide shuttles, (N-MePhe)n . These include diverse structural features such as various backbone stereochemistries or the presence of non-natural amino acids, including halogenated residues. In several cases, we assessed the BBB permeability of both the shuttles alone and linked to a few cargos. Our results show how factors such as stereochemistry or halogen content influences the passage across the BBB and, more importantly, opens the way to a strategy of peptide shuttles 'à la carte', in which a particular fine-tuned shuttle is used for each specific cargo. PMID:24665021

  18. Purinergic receptor P2RY12-dependent microglial closure of the injured blood-brain barrier.

    PubMed

    Lou, Nanhong; Takano, Takahiro; Pei, Yong; Xavier, Anna L; Goldman, Steven A; Nedergaard, Maiken

    2016-01-26

    Microglia are integral functional elements of the central nervous system, but the contribution of these cells to the structural integrity of the neurovascular unit has not hitherto been assessed. We show here that following blood-brain barrier (BBB) breakdown, P2RY12 (purinergic receptor P2Y, G-protein coupled, 12)-mediated chemotaxis of microglia processes is required for the rapid closure of the BBB. Mice treated with the P2RY12 inhibitor clopidogrel, as well as those in which P2RY12 was genetically ablated, exhibited significantly diminished movement of juxtavascular microglial processes and failed to close laser-induced openings of the BBB. Thus, microglial cells play a previously unrecognized protective role in the maintenance of BBB integrity following cerebrovascular damage. Because clopidogrel antagonizes the platelet P2Y12 receptor, it is widely prescribed for patients with coronary artery and cerebrovascular disease. As such, these observations suggest the need for caution in the postincident continuation of P2RY12-targeted platelet inhibition. PMID:26755608

  19. Astrocyte-derived VEGF-A drives blood-brain barrier disruption in CNS inflammatory disease.

    PubMed

    Argaw, Azeb Tadesse; Asp, Linnea; Zhang, Jingya; Navrazhina, Kristina; Pham, Trinh; Mariani, John N; Mahase, Sean; Dutta, Dipankar J; Seto, Jeremy; Kramer, Elisabeth G; Ferrara, Napoleone; Sofroniew, Michael V; John, Gareth R

    2012-07-01

    In inflammatory CNS conditions such as multiple sclerosis (MS), current options to treat clinical relapse are limited, and more selective agents are needed. Disruption of the blood-brain barrier (BBB) is an early feature of lesion formation that correlates with clinical exacerbation, leading to edema, excitotoxicity, and entry of serum proteins and inflammatory cells. Here, we identify astrocytic expression of VEGF-A as a key driver of BBB permeability in mice. Inactivation of astrocytic Vegfa expression reduced BBB breakdown, decreased lymphocyte infiltration and neuropathology in inflammatory and demyelinating lesions, and reduced paralysis in a mouse model of MS. Knockdown studies in CNS endothelium indicated activation of the downstream effector eNOS as the principal mechanism underlying the effects of VEGF-A on the BBB. Systemic administration of the selective eNOS inhibitor cavtratin in mice abrogated VEGF-A-induced BBB disruption and pathology and protected against neurologic deficit in the MS model system. Collectively, these data identify blockade of VEGF-A signaling as a protective strategy to treat inflammatory CNS disease. PMID:22653056

  20. Recent advances in the brain-to-blood efflux transport across the blood-brain barrier.

    PubMed

    Hosoya, Ken-ichi; Ohtsuki, Sumio; Terasaki, Tetsuya

    2002-11-01

    Elucidating the details of the blood-brain barrier (BBB) transport mechanism is a very important step towards successful drug targeting to the brain and understanding what happens in the brain. Although several brain uptake methods have been developed to characterize transport at the BBB, these are mainly useful for investigating influx transport across the BBB. In 1992, P-glycoprotein was found to act as an efflux pump for anti-cancer drugs at the BBB using primary cultured bovine brain endothelial cells. In order to determine the direct efflux transport from the brain to the circulating blood of exogenous compounds in vivo, the Brain Efflux Index method was developed to characterize several BBB efflux transport systems. Recently, we have established conditionally immortalized rat (TR-BBB) and mouse (TM-BBB) brain capillary endothelial cell lines from transgenic rats and mice harboring temperature-sensitive simian virus 40 large T-antigen gene to characterize the transport mechanisms at the BBB in vitro. TR-BBB and TM-BBB cells possess certain in vivo transport functions and express mRNAs for the BBB. Using a combination of newly developed in vivo and in vitro methods, we have elucidated the efflux transport mechanism at the BBB for neurosteroids, excitatory neurotransmitters, suppressive neurotransmitters, amino acids, and other organic anions to understand the physiological role played by the BBB as a detoxifying organ for the brain. PMID:12429456

  1. The TAM receptor Mertk protects against neuroinvasive viral infection by maintaining blood-brain barrier integrity.

    PubMed

    Miner, Jonathan J; Daniels, Brian P; Shrestha, Bimmi; Proenca-Modena, Jose L; Lew, Erin D; Lazear, Helen M; Gorman, Matthew J; Lemke, Greg; Klein, Robyn S; Diamond, Michael S

    2015-12-01

    The TAM receptors Tyro3, Axl and Mertk are receptor tyrosine kinases that dampen host innate immune responses following engagement with their ligands Gas6 and Protein S, which recognize phosphatidylserine on apoptotic cells. In a form of apoptotic mimicry, many enveloped viruses display phosphatidylserine on the outer leaflet of their membranes, enabling TAM receptor activation and downregulation of antiviral responses. Accordingly, we hypothesized that a deficiency of TAM receptors would enhance antiviral responses and protect against viral infection. Unexpectedly, mice lacking Mertk and/or Axl, but not Tyro3, exhibited greater vulnerability to infection with neuroinvasive West Nile and La Crosse encephalitis viruses. This phenotype was associated with increased blood-brain barrier permeability, which enhanced virus entry into and infection of the brain. Activation of Mertk synergized with interferon-β to tighten cell junctions and prevent virus transit across brain microvascular endothelial cells. Because TAM receptors restrict pathogenesis of neuroinvasive viruses, these findings have implications for TAM antagonists that are currently in clinical development. PMID:26523970

  2. Immune evasion by rabies viruses through the maintenance of blood-brain barrier integrity.

    PubMed

    Roy, Anirban; Hooper, D Craig

    2008-10-01

    The attenuated rabies virus (RV) strain Challenge Virus Standard (CVS)-F3 and a highly pathogenic strain associated with the silver-haired bats (SHBRV) can both be cleared from the central nervous system (CNS) tissues by appropriate antiviral immune mechanisms if the effectors are provided access across the blood-brain barrier (BBB). In the case of SHBRV infection, antiviral immunity develops normally in the periphery but fails to open the BBB, generally resulting in a lethal outcome. To determine whether or not an absence in the CNS targeted immune response is associated with the infection with other pathogenic RV strains, we have assessed the development of immunity, BBB permeability, and immune cell infiltration into the CNS tissues of mice infected with a variety of RV strains, including the dog variants responsible for the majority of human rabies cases. We demonstrate that the lethal outcomes of infection with a variety of known pathogenic RV strains are indeed associated with the inability to deliver immune effectors across the BBB. Survival from infection with certain of these viruses is improved in mice prone to CNS inflammation. The results suggest that competition between the activity of the immune effectors reaching CNS tissues and the inherent pathological attributes of the virus dictates the outcome and that intervention to deliver RV-specific immune effectors into CNS tissues may have general therapeutic value in rabies. PMID:19016377

  3. Ultrastructural and ultracytochemical studies on the blood-brain barrier in chronic relapsing experimental allergic encephalomyelitis.

    PubMed

    Kato, S; Nakamura, H

    1989-01-01

    We induced chronic relapsing experimental allergic encephalomyelitis (EAE), and studied the ultrastructural and ultracytochemical changes of the blood-brain barrier (BBB) in the demyelinating lesions of various stages of EAE. In the chronic, inactive stage with gliosis and perivascular fibrosis, the basal lamina (BL) of the perivascular processes of astrocytes was formed only partially, and neural parenchyma was not fully separated from the perivascular mesenchymal tissues by the BL of astrocytic processes. Vascular permeability of the BBB was studied using exogenous horseradish peroxidase (HRP) as the tracer: HRP extravasation was marked during the stages of both active myelin breakdown and removal of debris, and was recognized even at the inactive stage, although the degree was reduced to a very low level. The functions of the endothelia, assessed by ouabain-sensitive, K+-dependent p-nitrophenylphosphatase activity, were impaired as EAE progressed. The decrease in HRP leakage at the inactive stage suggests the endothelial impairment of active transport of metabolites including HRP. Along with the development of inflammatory demyelination in EAE, the BBB in affected areas became more and more altered, and gradual morphological and functional impairment of the BBB developed. PMID:2718744

  4. Blood-brain barrier dysfunction in disorders of the developing brain

    PubMed Central

    Moretti, Raffaella; Pansiot, Julien; Bettati, Donatella; Strazielle, Nathalie; Ghersi-Egea, Jean-François; Damante, Giuseppe; Fleiss, Bobbi; Titomanlio, Luigi; Gressens, Pierre

    2015-01-01

    Disorders of the developing brain represent a major health problem. The neurological manifestations of brain lesions can range from severe clinical deficits to more subtle neurological signs or behavioral problems and learning disabilities, which often become evident many years after the initial damage. These long-term sequelae are due at least in part to central nervous system immaturity at the time of the insult. The blood-brain barrier (BBB) protects the brain and maintains homeostasis. BBB alterations are observed during both acute and chronic brain insults. After an insult, excitatory amino acid neurotransmitters are released, causing reactive oxygen species (ROS)-dependent changes in BBB permeability that allow immune cells to enter and stimulate an inflammatory response. The cytokines, chemokines and other molecules released as well as peripheral and local immune cells can activate an inflammatory cascade in the brain, leading to secondary neurodegeneration that can continue for months or even years and finally contribute to post-insult neuronal deficits. The role of the BBB in perinatal disorders is poorly understood. The inflammatory response, which can be either acute (e.g., perinatal stroke, traumatic brain injury) or chronic (e.g., perinatal infectious diseases) actively modulates the pathophysiological processes underlying brain injury. We present an overview of current knowledge about BBB dysfunction in the developing brain during acute and chronic insults, along with clinical and experimental data. PMID:25741233

  5. Crossing the blood-brain-barrier with transferrin conjugated carbon dots: A zebrafish model study.

    PubMed

    Li, Shanghao; Peng, Zhili; Dallman, Julia; Baker, James; Othman, Abdelhameed M; Blackwelder, Patrica L; Leblanc, Roger M

    2016-09-01

    Drug delivery to the central nervous system (CNS) in biological systems remains a major medical challenge due to the tight junctions between endothelial cells known as the blood-brain-barrier (BBB). Here we use a zebrafish model to explore the possibility of using transferrin-conjugated carbon dots (C-Dots) to ferry compounds across the BBB. C-Dots have previously been reported to inhibit protein fibrillation, and they are also used to deliver drugs for disease treatment. In terms of the potential medical application of C-Dots for the treatment of CNS diseases, one of the most formidable challenges is how to deliver them inside the CNS. To achieve this in this study, human transferrin was covalently conjugated to C-Dots. The conjugates were then injected into the vasculature of zebrafish to examine the possibility of crossing the BBB in vivo via transferrin receptor-mediated endocytosis. The experimental observations suggest that the transferrin-C-Dots can enter the CNS while C-Dots alone cannot. PMID:27187189

  6. The Effects of Psychostimulant Drugs on Blood Brain Barrier Function and Neuroinflammation

    PubMed Central

    Kousik, Sharanya M.; Napier, T. Celeste; Carvey, Paul M.

    2012-01-01

    The blood brain barrier (BBB) is a highly dynamic interface between the central nervous system (CNS) and periphery. The BBB is comprised of a number of components and is part of the larger neuro(glio)vascular unit. Current literature suggests that psychostimulant drugs of abuse alter the function of the BBB which likely contributes to the neurotoxicities associated with these drugs. In both preclinical and clinical studies, psychostimulants including methamphetamine, MDMA, cocaine, and nicotine, produce BBB dysfunction through alterations in tight junction protein expression and conformation, increased glial activation, increased enzyme activation related to BBB cytoskeleton remodeling, and induction of neuroinflammatory pathways. These detrimental changes lead to increased permeability of the BBB and subsequent vulnerability of the brain to peripheral toxins. In fact, abuse of these psychostimulants, notably methamphetamine and cocaine, has been shown to increase the invasion of peripheral bacteria and viruses into the brain. Much work in this field has focused on the co-morbidity of psychostimulant abuse and human immunodeficiency virus (HIV) infection. As psychostimulants alter BBB permeability, it is likely that this BBB dysfunction results in increased penetration of the HIV virus into the brain thus increasing the risk of and severity of neuro AIDS. This review will provide an overview of the specific changes in components within the BBB associated with psychostimulant abuse as well as the implications of these changes in exacerbating the neuropathology associated with psychostimulant drugs and HIV co-morbidity. PMID:22754527

  7. Regulation of CovR expression in Group B Streptococcus impacts blood-brain barrier penetration.

    PubMed

    Lembo, Annalisa; Gurney, Michael A; Burnside, Kellie; Banerjee, Anirban; de los Reyes, Melissa; Connelly, James E; Lin, Wan-Jung; Jewell, Kelsea A; Vo, Anthony; Renken, Christian W; Doran, Kelly S; Rajagopal, Lakshmi

    2010-07-01

    Group B Streptococcus (GBS) is an important cause of invasive infections in humans. The pathogen encodes a number of virulence factors including the pluripotent beta-haemolysin/cytolysin (beta-H/C). As GBS has the disposition of both a commensal organism and an invasive pathogen, it is important for the organism to appropriately regulate beta-H/C and other virulence factors in response to the environment. GBS can repress transcription of beta-H/C using the two-component system, CovR/CovS. Recently, we described that the serine/threonine kinase Stk1 can phosphorylate CovR at threonine 65 to relieve repression of beta-H/C. In this study, we show that infection with CovR-deficient GBS strains resulted in increased sepsis. Although CovR-deficient GBS showed decreased ability to invade the brain endothelium in vitro, they were more proficient in induction of permeability and pro-inflammatory signalling pathways in brain endothelium and penetration of the blood-brain barrier (BBB) in vivo. Microarray analysis revealed that CovR positively regulates its own expression and regulates the expression of 153 genes. Collectively, our results suggest that the positive feedback loop which regulates CovR transcription modulates host cell interaction and immune defence and may facilitate the transition of GBS from a commensal organism to a virulent meningeal pathogen. PMID:20497331

  8. Trafficking of Endogenous Immunoglobulins by Endothelial Cells at the Blood-Brain Barrier

    PubMed Central

    Villaseñor, Roberto; Ozmen, Laurence; Messaddeq, Nadia; Grüninger, Fiona; Loetscher, Hansruedi; Keller, Annika; Betsholtz, Christer; Freskgård, Per-Ola; Collin, Ludovic

    2016-01-01

    The Blood-Brain Barrier (BBB) restricts access of large molecules to the brain. The low endocytic activity of brain endothelial cells (BECs) is believed to limit delivery of immunoglobulins (IgG) to the brain parenchyma. Here, we report that endogenous mouse IgG are localized within intracellular vesicles at steady state in BECs in vivo. Using high-resolution quantitative microscopy, we found a fraction of endocytosed IgG in lysosomes. We observed that loss of pericytes (key components of the BBB) in pdgf-bret/ret mice affects the intracellular distribution of endogenous mouse IgG in BECs. In these mice, endogenous IgG was not detected within lysosomes but instead accumulate at the basement membrane and brain parenchyma. Such IgG accumulation could be due to reduced lysosomal clearance and increased sorting to the abluminal membrane of BECs. Our results suggest that, in addition to low uptake from circulation, IgG lysosomal degradation may be a downstream mechanism by which BECs further restrict IgG access to the brain. PMID:27149947

  9. Alpha Adrenergic Induction of Transport of Lysosomal Enzyme across the Blood-Brain Barrier

    PubMed Central

    Urayama, Akihiko; Dohgu, Shinya; Robinson, Sandra M.; Sly, William S.; Grubb, Jeffery H.; Banks, William A

    2015-01-01

    The impermeability of the adult blood-brain barrier (BBB) to lysosomal enzymes impedes the ability to treat the central nervous system manifestations of lysosomal storage diseases. Here, we found that simultaneous stimulation of the alpha1 and alpha2 adrenoreceptor restores in adult mice the high rate of transport for the lysosomal enzyme P-GUS that is seen in neonates but lost with development. Beta adrenergics, other monoamines, and acetylcholine did not restore this transport. A high dose (500 microg/mouse) of clonidine, a strong alpha2 and weak alpha1 agonist, was able to act as monotherapy in the stimulation of P-GUS transport. Neither use of alpha1 plus alpha2 agonists nor the high dose clonidine disrupted the BBB to albumin. In situ brain perfusion and immunohistochemistry studies indicated that adrengerics act on transporters already at the luminal surface of brain endothelial cells. These results show that adrenergic stimulation, including monotherapy with clonidine, could be key for CNS enzyme replacement therapy. PMID:26545208

  10. Dimethyl fumarate attenuates cerebral edema formation by protecting the blood-brain barrier integrity.

    PubMed

    Kunze, Reiner; Urrutia, Andrés; Hoffmann, Angelika; Liu, Hui; Helluy, Xavier; Pham, Mirko; Reischl, Stefan; Korff, Thomas; Marti, Hugo H

    2015-04-01

    Brain edema is a hallmark of various neuropathologies, but the underlying mechanisms are poorly understood. We aim to characterize how tissue hypoxia, together with oxidative stress and inflammation, leads to capillary dysfunction and breakdown of the blood-brain barrier (BBB). In a mouse stroke model we show that systemic treatment with dimethyl fumarate (DMF), an antioxidant drug clinically used for psoriasis and multiple sclerosis, significantly prevented edema formation in vivo. Indeed, DMF stabilized the BBB by preventing disruption of interendothelial tight junctions and gap formation, and decreased matrix metalloproteinase activity in brain tissue. In vitro, DMF directly sustained endothelial tight junctions, inhibited inflammatory cytokine expression, and attenuated leukocyte transmigration. We also demonstrate that these effects are mediated via activation of the redox sensitive transcription factor NF-E2 related factor 2 (Nrf2). DMF activated the Nrf2 pathway as shown by up-regulation of several Nrf2 target genes in the brain in vivo, as well as in cerebral endothelial cells and astrocytes in vitro, where DMF also increased protein abundance of nuclear Nrf2. Finally, Nrf2 knockdown in endothelial cells aggravated subcellular delocalization of tight junction proteins during ischemic conditions, and attenuated the protective effect exerted by DMF. Overall, our data suggest that DMF protects from cerebral edema formation during ischemic stroke by targeting interendothelial junctions in an Nrf2-dependent manner, and provide the basis for a completely new approach to treat brain edema. PMID:25725349

  11. Oligodendrocyte Precursor Cells Support Blood-Brain Barrier Integrity via TGF-β Signaling

    PubMed Central

    Maeda, Mitsuyo; Miyamoto, Nobukazu; Liang, Anna C.; Hayakawa, Kazuhide; Pham, Loc-Duyen D.; Suwa, Fumihiko; Taguchi, Akihiko; Matsuyama, Tomohiro; Ihara, Masafumi; Kim, Kyu-Won; Lo, Eng H.; Arai, Ken

    2014-01-01

    Trophic coupling between cerebral endothelium and their neighboring cells is required for the development and maintenance of blood-brain barrier (BBB) function. Here we report that oligodendrocyte precursor cells (OPCs) secrete soluble factor TGF-β1 to support BBB integrity. Firstly, we prepared conditioned media from OPC cultures and added them to cerebral endothelial cultures. Our pharmacological experiments showed that OPC-conditioned media increased expressions of tight-junction proteins and decreased in vitro BBB permeability by activating TGB-β-receptor-MEK/ERK signaling pathway. Secondly, our immuno-electron microscopic observation revealed that in neonatal mouse brains, OPCs attach to cerebral endothelial cells via basal lamina. And finally, we developed a novel transgenic mouse line that TGF-β1 is knocked down specifically in OPCs. Neonates of these OPC-specific TGF-β1 deficient mice (OPC-specific TGF-β1 partial KO mice: PdgfraCre/Tgfb1flox/wt mice or OPC-specific TGF-β1 total KO mice: PdgfraCre/Tgfb1flox/flox mice) exhibited cerebral hemorrhage and loss of BBB function. Taken together, our current study demonstrates that OPCs increase BBB tightness by upregulating tight junction proteins via TGF-β signaling. Although astrocytes and pericytes are well-known regulators of BBB maturation and maintenance, these findings indicate that OPCs also play a pivotal role in promoting BBB integrity. PMID:25078775

  12. Reversible opening of the blood-brain barrier by anti-bacterial antibodies.

    PubMed Central

    Tuomanen, E I; Prasad, S M; George, J S; Hoepelman, A I; Ibsen, P; Heron, I; Starzyk, R M

    1993-01-01

    The leukocyte adhesion molecule CR3 (CD11b/CD18, Mac-1) promotes leukocyte transmigration into tissues by engaging an unknown cognate ligand on the surface of vascular endothelial cells. Filamentous hemagglutinin (FHA), an adhesin of the bacterium Bordetella pertussis, binds to CR3. We hypothesized that FHA mimics the native ligand for the CR3 integrin on endothelial cells and predicted that anti-FHA antibodies should bind to endothelial cells, interfere with leukocyte recruitment, and induce endothelial permeability. Anti-FHA monoclonal antibodies bound to cerebral microvessels in sections from human brain and upon intravenous injection into rabbits. Antibody binding correlated with the ability to recognize two polypeptides in extracts of human cerebral vessels that were also bound by CD18. In vivo, antibody binding not only interfered with transmigration of leukocytes into cerebrospinal fluid but also induced a dose-dependent reversible increase in blood-brain barrier permeability sufficient to improve delivery of intravenously administered therapeutic agents to brain parenchyma. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:8102802

  13. Role of Microfluidics in Blood-Brain Barrier Permeability Cell Culture Modeling: Relevance to CNS Disorders.

    PubMed

    Rusanov, Alexander L; Luzgina, Natalia G; Barreto, George E; Aliev, Gjumrakch

    2016-01-01

    In vitro modeling of the human blood-brain barrier (BBB) is critical for pre-clinical evaluation and predicting the permeability of newly developed potentially neurotoxic and neurotrophic drugs. Here we summarize the specific structural and functional features of endothelial cells as a key component of the BBB and compare analysis of different cell culture models in reflecting these features. Particular attention is paid to cellular models of the BBB in microfluidic devices capable of circulating nutrient media to simulate the blood flow of the brain. In these conditions, it is possible to reproduce a number of factors affecting endothelial cells under physiological conditions, including shear stress. In comparison with static cell models, concentration gradients, which determine the velocity of transport of substances, reproduce more accurately conditions of nutrient medium flow, since they eliminate the accumulation of substances near the basal membrane of cells, not typical for the situation in vivo. Co-cultivation of different types of cells forming the BBB, in separate cell chambers connected by microchannels, allows to evaluate the mutual influences of cells under normal conditions and when exposed to the test substance. New experimental possibilities that can be achieved through modeling of BBB in microfluidic devices determine the feasibility of their use in the practice for pre-clinical studies of novel drugs against neurodegenerative diseases. PMID:26831260

  14. Blood brain barrier breakdown was found in non-infarcted area after 2-h MCAO.

    PubMed

    Wang, Xiaona; Liu, Yushan; Sun, Yanyun; Liu, Wenlan; Jin, Xinchun

    2016-04-15

    The blood brain barrier (BBB) could be damaged within the thrombolytic time window and is considered to be a precursor to hemorrhagic transformation during reperfusion. Although we have recently reported the association between BBB damage and tissue injury within the thrombolytic time window, our knowledge about this early BBB damage is limited. In this study, rats were subjected to 2-h middle cerebral artery occlusion (MCAO) followed by 10 min reperfusion with Evan's blue as a tracer to detect BBB damage. Rat brain was sliced into 10 consecutive sections and with TTC staining, a macro and full view of the spatial distribution of BBB damage and tissue injury could be clearly seen in the same group of animals. After 2-h MCAO, tissue injury started from 2nd slice and the BBB leakage started from the 5th slice, of note, there is no colocalization between BBB damage and tissue injury. Fluoro Jade B was employed to explore the localization of neuronal degeneration, and our results showed that 2-h MCAO produced greater number of positive cells in ischemic cortex and dorsal striatum than other areas. More important, 2-h MCAO induced occludin but not claudin-5 degradation in the ischemic hemisphere and pretreatment with MMP inhibitor GM6001 significantly reduced occludin degradation as well as BBB damage detected by IgG leakage. Taken together, our findings demonstrated a "mismatch" between ischemic tissue injury and BBB leakage and a differential degradation of occludin and claudin-5 by MMP-2 after 2-h MCAO. PMID:27000223

  15. Regulation of ABC efflux transporters at blood-brain barrier in health and neurological disorders.

    PubMed

    Qosa, Hisham; Miller, David S; Pasinelli, Piera; Trotti, Davide

    2015-12-01

    The strength of the blood-brain barrier (BBB) in providing protection to the central nervous system from exposure to circulating chemicals is maintained by tight junctions between endothelial cells and by a broad range of transporter proteins that regulate exchange between CNS and blood. The most important transporters that restrict the permeability of large number of toxins as well as therapeutic agents are the ABC transporters. Among them, P-gp, BCRP, MRP1 and MRP2 are the utmost studied. These efflux transporters are neuroprotective, limiting the brain entry of neurotoxins; however, they could also restrict the entry of many therapeutics and contribute to CNS pharmacoresistance. Characterization of several regulatory pathways that govern expression and activity of ABC efflux transporters in the endothelium of brain capillaries have led to an emerging consensus that these processes are complex and contain several cellular and molecular elements. Alterations in ABC efflux transporters expression and/or activity occur in several neurological diseases. Here, we review the signaling pathways that regulate expression and transport activity of P-gp, BCRP, MRP1 and MRP2 as well as how their expression/activity changes in neurological diseases. This article is part of a Special Issue entitled SI: Neuroprotection. PMID:26187753

  16. Neuromodulation accompanying focused ultrasound-induced blood-brain barrier opening

    PubMed Central

    Chu, Po-Chun; Liu, Hao-Li; Lai, Hsin-Yi; Lin, Chung-Yin; Tsai, Hong-Chieh; Pei, Yu-Cheng

    2015-01-01

    Burst-mode focused ultrasound (FUS) induces microbubble cavitation in the vasculature and temporarily disrupts the blood-brain barrier (BBB) to enable therapeutic agent delivery. However, it remains unclear whether FUS-induced BBB opening is accompanied by neuromodulation. Here we characterized the functional effects of FUS-induced BBB opening by measuring changes in somatosensory evoked potentials (SSEPs) and blood-oxygen-level dependent (BOLD) responses. Rats underwent burst-mode FUS (mechanical index (MI) of 0.3, 0.55 or 0.8) to the forelimb region in the left primary somatosensory cortex to induce BBB opening. Longitudinal measurements were followed for up to 1 week to characterize the temporal dynamics of neuromodulation. We observed that 0.8-MI FUS profoundly suppressed SSEP amplitude and prolonged latency, and this effect lasted 7 days. 0.55-MI FUS resulted in minimal and short-term suppression of SSEP for less than 60 minutes and didn’t affect latency. BOLD responses were also suppressed in an MI-dependent manner, mirroring the effect on SSEPs. Furthermore, repetitive delivery of 0.55-MI FUS every 3 days elicited no accumulative effects on SSEPs or tissue integrity. This is the first evidence that FUS-induced BBB opening is accompanied by reversible changes in neuron responses, and may provide valuable insight toward the development of FUS-induced BBB opening for clinical applications. PMID:26490653

  17. Transport Rankings of Non-Steroidal Antiinflammatory Drugs across Blood-Brain Barrier In Vitro Models

    PubMed Central

    Novakova, Iveta; Subileau, Eva-Anne; Toegel, Stefan; Gruber, Daniela; Lachmann, Bodo; Urban, Ernst; Chesne, Christophe; Noe, Christian R.; Neuhaus, Winfried

    2014-01-01

    The aim of this work was to conduct a comprehensive study about the transport properties of NSAIDs across the blood-brain barrier (BBB) in vitro. Transport studies with celecoxib, diclofenac, ibuprofen, meloxicam, piroxicam and tenoxicam were accomplished across Transwell models based on cell line PBMEC/C1-2, ECV304 or primary rat brain endothelial cells. Single as well as group substance studies were carried out. In group studies substance group compositions, transport medium and serum content were varied, transport inhibitors verapamil and probenecid were added. Resulted permeability coefficients were compared and normalized to internal standards diazepam and carboxyfluorescein. Transport rankings of NSAIDs across each model were obtained. Single substance studies showed similar rankings as corresponding group studies across PBMEC/C1-2 or ECV304 cell layers. Serum content, glioma conditioned medium and inhibitors probenecid and verapamil influenced resulted permeability significantly. Basic differences of transport properties of the investigated NSAIDs were similar comparing all three in vitro BBB models. Different substance combinations in the group studies and addition of probenecid and verapamil suggested that transporter proteins are involved in the transport of every tested NSAID. Results especially underlined the importance of same experimental conditions (transport medium, serum content, species origin, cell line) for proper data comparison. PMID:24466249

  18. Microfluidic modeling of the effects of nanoparticles on the blood-brain barrier in flow

    NASA Astrophysics Data System (ADS)

    Schwait, Craig; Hartman, Ryan; Bao, Yuping; Xu, Yaolin

    2011-11-01

    The difficulty of diffusing drugs across the blood-brain barrier (BBB) has caused an impasse for many brain treatments. Nanoparticles (NPs), to which drugs can adsorb, attach, or be entrapped, have the potential to deliver drugs past the BBB. Before nanoparticles can be used, their effects on the BBB and brain must be ascertained. Previous steady-state studies fall short for closely modeling in vivo conditions . Convection of nanoparticles is ignored, and endothelial cells' (ECs) morphology differs based on loading conditions; in vitro loading with continuous flow exhibit ECs indicating a more similar in vivo phenotype. NPs interact with monocytes prior to the BBB, and their toxicity effects were measured in flow conditions using both Trypan Blue cell counting and cell proliferation assays. The microfluidic device designed to model the BBB contained a concentric PES hollow fiber porous membrane in PFA tubing. Full use of the device will include ECs adhered on the inner surface and astrocytes adhered to the outer surface of the PES membrane to model cerebrovascular capillaries. Funded by NSF REU Site 1062611.

  19. Role of the blood-brain barrier in the nutrition of the central nervous system.

    PubMed

    Campos-Bedolla, Patricia; Walter, Fruzsina R; Veszelka, Szilvia; Deli, Mária A

    2014-11-01

    The blood-brain barrier (BBB) is a dynamic and complex interface between the blood and the central nervous system regulating brain homeostasis. Major functions of the BBB include the transport of nutrients and protection of the brain from toxic compounds. This review summarizes the most important transport pathways contributing to the nutrition of the brain. Carrier-mediated transport selectively delivers small molecules like sugars, amino acids, vitamins, and trace elements. Large biomolecules, lipoproteins, peptide and protein hormones cross the BBB by receptor-mediated transport. Active efflux transporters participate in the brain efflux of endogenous metabolites as well as toxins, xenobiotics and drugs. Dysfunction in the transport of nutrients at the BBB is described in several neurological disorders and diseases. The BBB penetration of neuroprotective nutrients, especially plant polyphenols and alkaloids, their potential protective effect on brain endothelium and the interaction of nutraceuticals with active efflux transporters at the BBB are discussed. In vitro BBB models to examine nutrient transport are also presented. PMID:25481827

  20. Blood-brain barrier breakdown as a therapeutic target in traumatic brain injury.

    PubMed

    Shlosberg, Dan; Benifla, Mony; Kaufer, Daniela; Friedman, Alon

    2010-07-01

    Traumatic brain injury (TBI) is the leading cause of death in young adults and children. The treatment of TBI in the acute phase has improved substantially; however, the prevention and management of long-term complications remain a challenge. Blood-brain barrier (BBB) breakdown has often been documented in patients with TBI, but the role of such vascular pathology in neurological dysfunction has only recently been explored. Animal studies have demonstrated that BBB breakdown is involved in the initiation of transcriptional changes in the neurovascular network that ultimately lead to delayed neuronal dysfunction and degeneration. Brain imaging data have confirmed the high incidence of BBB breakdown in patients with TBI and suggest that such pathology could be used as a biomarker in the clinic and in drug trials. Here, we review the neurological consequences of TBI, focusing on the long-term complications of such injuries. We present the clinical evidence for involvement of BBB breakdown in TBI and examine the primary and secondary mechanisms that underlie such pathology. We go on to consider the consequences of BBB injury, before analyzing potential mechanisms linking vascular pathology to neuronal dysfunction and degeneration, and exploring possible targets for treatment. Finally, we highlight areas for future basic research and clinical studies into TBI. PMID:20551947

  1. Oxidative stress and blood-brain barrier dysfunction under particular consideration of matrix metalloproteinases.

    PubMed

    Lehner, Christine; Gehwolf, Renate; Tempfer, Herbert; Krizbai, Istvan; Hennig, Bernhard; Bauer, Hans-Christian; Bauer, Hannelore

    2011-09-01

    A cell's "redox" (oxidation and reduction) state is determined by the sum of all redox processes yielding reactive oxygen species (ROS), reactive nitrogen species (RNS), and other reactive intermediates. Low amounts of ROS/RNS are generated by different mechanisms in every cell and are important regulatory mediators in many signaling processes (redox signaling). When the physiological balance between the generation and elimination of ROS/RNS is disrupted, oxidative/nitrosative stress with persistent oxidative damage of the organism occurs. Oxidative stress has been suggested to act as initiator and/or mediator of many human diseases. The cerebral vasculature is particularly susceptible to oxidative stress, which is critical since cerebral endothelial cells play a major role in the creation and maintenance of the blood-brain barrier (BBB). This article will only contain a focused introduction on the biochemical background of redox signaling, since this has been reported already in a series of excellent recent reviews. The goal of this work is to increase the understanding of basic mechanisms underlying ROS/RNS-induced BBB disruption, with a focus on the role of matrix metalloproteinases, which, after all, appear to be a key mediator in the initiation and progression of BBB damage elicited by oxidative stress. PMID:21294658

  2. Trafficking of Endogenous Immunoglobulins by Endothelial Cells at the Blood-Brain Barrier.

    PubMed

    Villaseñor, Roberto; Ozmen, Laurence; Messaddeq, Nadia; Grüninger, Fiona; Loetscher, Hansruedi; Keller, Annika; Betsholtz, Christer; Freskgård, Per-Ola; Collin, Ludovic

    2016-01-01

    The Blood-Brain Barrier (BBB) restricts access of large molecules to the brain. The low endocytic activity of brain endothelial cells (BECs) is believed to limit delivery of immunoglobulins (IgG) to the brain parenchyma. Here, we report that endogenous mouse IgG are localized within intracellular vesicles at steady state in BECs in vivo. Using high-resolution quantitative microscopy, we found a fraction of endocytosed IgG in lysosomes. We observed that loss of pericytes (key components of the BBB) in pdgf-b(ret/ret) mice affects the intracellular distribution of endogenous mouse IgG in BECs. In these mice, endogenous IgG was not detected within lysosomes but instead accumulate at the basement membrane and brain parenchyma. Such IgG accumulation could be due to reduced lysosomal clearance and increased sorting to the abluminal membrane of BECs. Our results suggest that, in addition to low uptake from circulation, IgG lysosomal degradation may be a downstream mechanism by which BECs further restrict IgG access to the brain. PMID:27149947

  3. Unilateral Opening of Rat Blood-Brain Barrier Assisted by Diagnostic Ultrasound Targeted Microbubbles Destruction

    PubMed Central

    Cui, Hai; Zhu, Qiong; Hua, Xing; Xia, Hongmei; Tan, Kaibin; Gao, Yunhua; Zhao, Jing

    2016-01-01

    Objective. Blood-brain barrier (BBB) is a key obstacle that prevents the medication from blood to the brain. Microbubble-enhanced cavitation by focused ultrasound can open the BBB and proves to be valuable in the brain drug delivery. The study aimed to explore the feasibility, efficacy, and safety of unilateral opening of BBB using diagnostic ultrasound targeted microbubbles destruction in rats. Methods. A transtemporal bone irradiation of diagnostic ultrasound and intravenous injection of lipid-coated microbubbles were performed at unilateral hemisphere. Pathological changes were monitored. Evans Blue extravasation grades, extraction from brain tissue, and fluorescence optical density were quantified. Lanthanum nitrate was traced by transmission electron microscopy. Results. After diagnostic ultrasound mediated microbubbles destruction, Evans Blue extravasation and fluorescence integrated optical density were significantly higher in the irradiated hemisphere than the contralateral side (all p < 0.01). Erythrocytes extravasations were demonstrated in the ultrasound-exposed hemisphere (4 ± 1, grade 2) while being invisible in the control side. Lanthanum nitrate tracers leaked through interendothelial cleft and spread to the nerve fiber existed in the irradiation side. Conclusions. Transtemporal bone irradiation under DUS mediated microbubble destruction provides us with a more accessible, safer, and higher selective BBB opening approach in rats, which is advantageous in brain targeted drugs delivery. PMID:27579317

  4. The TAM receptor Mertk protects against neuroinvasive viral infection by maintaining blood-brain barrier integrity

    PubMed Central

    Miner, Jonathan J.; Daniels, Brian P.; Shrestha, Bimmi; Proenca-Modena, Jose L.; Lew, Erin D.; Lazear, Helen M.; Gorman, Matthew J.; Lemke, Greg; Klein, Robyn S.; Diamond, Michael S.

    2015-01-01

    The TAM receptors Tyro3, Axl, and Mertk are receptor tyrosine kinases that dampen host innate immune responses following engagement with their ligands, Gas6 and Protein S, which recognize phosphatidylserine on apoptotic cells. In a form of apoptotic mimicry, many enveloped viruses display phosphatidylserine on the outer leaflet of their membranes, enabling TAM receptor activation and down-regulation of antiviral responses. Accordingly, we hypothesized that a deficiency of TAM receptors would enhance antiviral responses and protect against viral infection. Unexpectedly, mice lacking Mertk and/or Axl but not Tyro3 exhibited greater vulnerability to infection with neuroinvasive West Nile and La Crosse viruses. This phenotype was associated with increased blood-brain barrier permeability, which enhanced virus entry into and infection of the brain. Activation of Mertk synergized with IFN-β to tighten cell junctions and prevent virus transit across brain microvascular endothelial cells. Because TAM receptors restrict pathogenesis of neuroinvasive viruses, these findings have implications for TAM antagonists that are currently in clinical development. PMID:26523970

  5. Angiogenesis of the blood-brain barrier in vitro and the function of cerebral pericytes.

    PubMed

    Ramsauer, Markus; Krause, Dorothee; Dermietzel, Rolf

    2002-08-01

    Cerebral pericytes constitute an essential component of the blood-brain barrier (BBB) and are involved in blood vessel assembly. Recently, we reported on the induction of a BBB-specific enzyme expressed by cerebral pericytes (pericytic aminopeptidase N/pAPN) in coculture with cerebral endothelial cells. We completed this in vitro BBB system by adding astrocytes to these mixed cultures of endothelial cells and pericytes. Under these triculture conditions, endothelial cells and pericytes reorganize into capillary-like structures (CLSs). Capillary formation can also be achieved by the application of transforming growth factor beta 1 (TGF-b1) in the culture medium of endothelial-pericyte cultures lacking astrocytes. In contrast to the effect achieved by astrocytes, pericytes did not assemble with endothelial cells. In both cases (application of astrocytes or TGF-b1), endothelial cells underwent apoptosis. However, endothelial cells that form CLSs in the presence of pericytes appeared to be resistant to induction of apoptosis. On the basis of these observations, we concluded that astrocytes have a profound influence on the morphogenetic events underlying the organization of the vessel wall; that the effect of TGF-b1 is different from the astrocytic effect because it lacks induction of endothelial-pericyte association; and that pericytes stabilize CLSs formed by endothelial cells in coculture with astrocytes. PMID:12153997

  6. Significance of Lipid Composition in a Blood Brain Barrier-Mimetic PAMPA Assay

    PubMed Central

    Campbell, Scott D.; Regina, Karen J.; Kharasch, Evan D.

    2014-01-01

    Endothelial cells forming the blood-brain barrier limit drug access into the brain, due to tight junctions, membrane drug transporters, and unique lipid composition. Passive permeability, thought to mediate drug access, is typically tested using porcine whole brain lipid. However human endothelial cell lipid composition differs. This investigation evaluated the influence of lipid composition on passive permeability across artificial membranes. Permeability of CNS-active drugs across an immobilized lipid membrane was determined using three lipid models: crude extract from whole pig brain, human brain microvessel lipid, and microvessel lipid plus cholesterol. Lipids were immobilized on polyvinylidene difluoride, forming donor and receiver chambers, in which drug concentration were measured after 2 hr. The log of effective permeability was then calculated using the measured concentrations. Permeability of small, neutral compounds was unaffected by lipid composition. Several structurally diverse drugs were highly permeable in porcine whole brain lipid but 1–2 orders of magnitude less permeable across human brain endothelial cell lipid. Inclusion of cholesterol had the greatest influence on bulky amphipathic compounds such as glucuronide conjugates. Lipid composition markedly influences passive permeability. This was most apparent for charged or bulky compounds. These results demonstrate the importance of using species-specific lipid models in passive permeability assays. PMID:23945876

  7. Evolution of blood-brain barrier damage associated with changes in brain metabolites following acute ischemia.

    PubMed

    Yan, Gen; Xuan, Yinghua; Dai, Zhuozhi; Zhang, Guishan; Xu, Haiyun; Mikulis, David; Wu, Renhua

    2015-11-11

    Stroke is a serious medical condition that requires emergency care. In the case of ischemic stroke, ischemia may lead to damage to the blood-brain barrier (BBB); the damage in turn may exacerbate the condition. Therefore, noninvasive detection of BBB damage represents a challenge for experimental and clinical researchers. In this study, we assessed the onset of BBB disruption by means of T1-weighted images with administration of the contrast enhancement agent gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) and related BBB breakdown to brain metabolite changes in proton magnetic resonance spectrum (H-MRS) in the infarcted site following middle cerebral artery occlusion (MCAO) in rats. It was shown that MCAO for 30 min and 1.5 h caused no Gd-DTPA signal change in the T1-weighted images, whereas MCAO for 1 h significantly altered some of H-MRS brain metabolites, suggesting that brain metabolite changes occurred earlier than BBB damage after ischemic stroke. MCAO for 2 h caused BBB breakdown, which was related to changes in the levels of some brain metabolites detected by H-MRS. Between the second and the third hour after MCAO, brain metabolite changes continued as the result of BBB breakdown and the concurrent overperfusion to the infarcted site, which may ameliorate the metabolite changes, thus compensating for the functional failures of the brain after stroke. PMID:26366833

  8. Blood-brain barrier transport of choline is reduced in the aged rat.

    PubMed

    Mooradian, A D

    1988-02-01

    An age-related impairment in choline transport across the blood-brain barrier (BBB) may contribute to the cholinergic mechanisms of geriatric memory dysfunction. To test this hypothesis, the brain choline uptake in male Fisher 344 rats at 2, 18 and 24 months of age was studied using the Oldendorf technique. The Vmax of choline transport in the 24-month-old rats (0.05 +/- 0.04 nmol/min/g) was significantly lower than that in the 2-month-old rat (2.5 +/- 1.0 nmol/min/g) (P less than 0.05). The Km of transport in old rats (13 +/- 35 microM) was also significantly smaller than the value in 24-month-old rats (450 +/- 195 microM), while the constant of the non-saturable component of the transport, Kd, was not significantly different in older rats (1.2 +/- 0.3 vs 0.6 +/- 0.1 microliter/min/g). These results indicate that the carrier in old rats has reduced capacity and increased affinity to choline. The reduced choline carrier capacity explains the significant decrease in BBB choline transport in aged rats. PMID:3359216

  9. Blood-Brain Barrier Alterations Provide Evidence of Subacute Diaschisis in an Ischemic Stroke Rat Model

    PubMed Central

    Garbuzova-Davis, Svitlana; Rodrigues, Maria C. O.; Hernandez-Ontiveros, Diana G.; Tajiri, Naoki; Frisina-Deyo, Aric; Boffeli, Sean M.; Abraham, Jerry V.; Pabon, Mibel; Wagner, Andrew; Ishikawa, Hiroto; Shinozuka, Kazutaka; Haller, Edward; Sanberg, Paul R.; Kaneko, Yuji; Borlongan, Cesario V.

    2013-01-01

    Background Comprehensive stroke studies reveal diaschisis, a loss of function due to pathological deficits in brain areas remote from initial ischemic lesion. However, blood-brain barrier (BBB) competence in subacute diaschisis is uncertain. The present study investigated subacute diaschisis in a focal ischemic stroke rat model. Specific focuses were BBB integrity and related pathogenic processes in contralateral brain areas. Methodology/Principal Findings In ipsilateral hemisphere 7 days after transient middle cerebral artery occlusion (tMCAO), significant BBB alterations characterized by large Evans Blue (EB) parenchymal extravasation, autophagosome accumulation, increased reactive astrocytes and activated microglia, demyelinization, and neuronal damage were detected in the striatum, motor and somatosensory cortices. Vascular damage identified by ultrastuctural and immunohistochemical analyses also occurred in the contralateral hemisphere. In contralateral striatum and motor cortex, major ultrastructural BBB changes included: swollen and vacuolated endothelial cells containing numerous autophagosomes, pericyte degeneration, and perivascular edema. Additionally, prominent EB extravasation, increased endothelial autophagosome formation, rampant astrogliosis, activated microglia, widespread neuronal pyknosis and decreased myelin were observed in contralateral striatum, and motor and somatosensory cortices. Conclusions/Significance These results demonstrate focal ischemic stroke-induced pathological disturbances in ipsilateral, as well as in contralateral brain areas, which were shown to be closely associated with BBB breakdown in remote brain microvessels and endothelial autophagosome accumulation. This microvascular damage in subacute phase likely revealed ischemic diaschisis and should be considered in development of treatment strategies for stroke. PMID:23675488

  10. A Quantitative MRI Method for Imaging Blood-Brain Barrier Leakage in Experimental Traumatic Brain Injury

    PubMed Central

    Watts, Lora Talley; Jiang, Zhao; Shen, Qiang; Li, Yunxia; Duong, Timothy Q.

    2014-01-01

    Blood-brain barrier (BBB) disruption is common following traumatic brain injury (TBI). Dynamic contrast enhanced (DCE) MRI can longitudinally measure the transport coefficient Ktrans which reflects BBB permeability. Ktrans measurements however are not widely used in TBI research because it is generally considered to be noisy and possesses low spatial resolution. We improved spatiotemporal resolution and signal sensitivity of Ktrans MRI in rats by using a high-sensitivity surface transceiver coil. To overcome the signal drop off profile of the surface coil, a pre-scan module was used to map the flip angle (B1 field) and magnetization (M0) distributions. A series of T1-weighted gradient echo images were acquired and fitted to the extended Kety model with reversible or irreversible leakage, and the best model was selected using F-statistics. We applied this method to study the rat brain one hour following controlled cortical impact (mild to moderate TBI), and observed clear depiction of the BBB damage around the impact regions, which matched that outlined by Evans Blue extravasation. Unlike the relatively uniform T2 contrast showing cerebral edema, Ktrans shows a pronounced heterogeneous spatial profile in and around the impact regions, displaying a nonlinear relationship with T2. This improved Ktrans MRI method is also compatible with the use of high-sensitivity surface coil and the high-contrast two-coil arterial spin-labeling method for cerebral blood flow measurement, enabling more comprehensive investigation of the pathophysiology in TBI. PMID:25478693

  11. Vascular Endothelial Growth Factors Enhance the Permeability of the Mouse Blood-brain Barrier

    PubMed Central

    Jiang, Shize; Xia, Rui; Jiang, Yong; Wang, Lei; Gao, Fabao

    2014-01-01

    The blood-brain barrier (BBB) impedes entry of many drugs into the brain, limiting clinical efficacy. A safe and efficient method for reversibly increasing BBB permeability would greatly facilitate central nervous system (CNS) drug delivery and expand the range of possible therapeutics to include water soluble compounds, proteins, nucleotides, and other large molecules. We examined the effect of vascular endothelial growth factor (VEGF) on BBB permeability in Kunming (KM) mice. Human VEGF165 was administered to treatment groups at two concentrations (1.6 or 3.0 µg/mouse), while controls received equal-volume saline. Changes in BBB permeability were measured by parenchymal accumulation of the contrast agent Gd-DTPA as assessed by 7 T magnetic resonance imaging (MRI). Mice were then injected with Evans blue, sacrificed 0.5 h later, and perfused transcardially. Brains were removed, fixed, and sectioned for histological study. Both VEGF groups exhibited a significantly greater signal intensity from the cerebral cortex and basal ganglia than controls (P<0.001). Evans blue fluorescence intensity was higher in the parenchyma and lower in the cerebrovasculature of VEGF-treated animals compared to controls. No significant brain edema was observed by diffusion weighted MRI (DWI) or histological staining. Exogenous application of VEGF can increase the permeability of the BBB without causing brain edema. Pretreatment with VEGF may be a feasible method to facilitate drug delivery into the CNS. PMID:24551038

  12. TLR4 induces CCR7-dependent monocytes transmigration through the blood-brain barrier.

    PubMed

    Paradis, Alexandre; Bernier, Stéphane; Dumais, Nancy

    2016-06-15

    In this study, we examined whether bacterial pathogen-associated molecular patterns recognized by toll-like receptors (TLRs) can modify the CCR7-dependent migration of human monocytes. MonoMac-1 (MM-1) cells and freshly isolated human monocytes were cultivated in the presence of agonists for TLR4 (which senses lipopolysaccharides from gram-negative bacteria), TLR1/2 (which senses peptidoglycan from gram-positive bacteria), and TLR9 (which recognizes bacterial DNA rich in unmethylated CpG DNA). CCR7 mRNA transcription was measured using quantitative reverse transcription polymerase chain reaction and protein expression was examined using flow cytometry. CCR7 function was monitored using migration and transmigration assays in response to CCL19/CCL21, which are natural ligands for CCR7. Our results show that TLR4 strongly increases monocyte migratory capacity in response to CCL19 in chemotaxis and transmigration assays in a model that mimics the human blood-brain barrier, whereas TLR1/2 and 9 have no effect. Examination of monocyte migration in response to TLRs that are activated by bacterial components would contribute to understanding the excessive monocyte migration that characterizes the pathogenesis of bacterial infections and/or neuroinflammatory diseases. PMID:27235343

  13. Membrane configuration optimization for a murine in vitro blood-brain barrier model.

    PubMed

    Wuest, Diane M; Wing, Allison M; Lee, Kelvin H

    2013-01-30

    A powerful experimental tool used to study the dynamic functions of the blood-brain barrier (BBB) is an in vitro cellular based system utilizing cell culture inserts in multi-well plates. Currently, usage of divergent model configurations without explanation of selected variable set points renders data comparisons difficult and limits widespread understanding. This work presents for the first time in literature a comprehensive screening study to optimize membrane configuration, with aims to unveil influential membrane effects on the ability of cerebral endothelial cells to form a tight monolayer. First, primary murine brain endothelial cells and astrocytes were co-cultured in contact and non-contact orientations on membranes of pore diameter sizes ranging from 0.4 μm to 8.0 μm, and the non-contact orientation and smallest pore diameter size were shown to support a significantly tighter monolayer formation. Then, membranes made from polyethylene terephthalate (PET) and polycarbonate (PC) purchased from three different commercial sources were compared, and PET membranes purchased from two manufacturers facilitated a significantly tighter monolayer formation. Models were characterized by transendothelial electrical resistance (TEER), sodium fluorescein permeability, and immunocytochemical labeling of tight junction proteins. Finally, a murine brain endothelial cell line, bEnd.3, was grown on the different membranes, and similar results were obtained with respect to optimal membrane configuration selection. The results and methodology presented here on high throughput 24-well plate inserts can be translated to other BBB systems to advance model understanding. PMID:23131353

  14. Transmigration of Neural Stem Cells across the Blood Brain Barrier Induced by Glioma Cells

    PubMed Central

    Díaz-Coránguez, Mónica; Segovia, José; López-Ornelas, Adolfo; Puerta-Guardo, Henry; Ludert, Juan; Chávez, Bibiana; Meraz-Cruz, Noemi; González-Mariscal, Lorenza

    2013-01-01

    Transit of human neural stem cells, ReNcell CX, through the blood brain barrier (BBB) was evaluated in an in vitro model of BBB and in nude mice. The BBB model was based on rat brain microvascular endothelial cells (RBMECs) cultured on Millicell inserts bathed from the basolateral side with conditioned media (CM) from astrocytes or glioma C6 cells. Glioma C6 CM induced a significant transendothelial migration of ReNcells CX in comparison to astrocyte CM. The presence in glioma C6 CM of high amounts of HGF, VEGF, zonulin and PGE2, together with the low abundance of EGF, promoted ReNcells CX transmigration. In contrast cytokines IFN-α, TNF-α, IL-12p70, IL-1β, IL-6, IL-8 and IL-10, as well as metalloproteinases -2 and -9 were present in equal amounts in glioma C6 and astrocyte CMs. ReNcells expressed the tight junction proteins occludin and claudins 1, 3 and 4, and the cell adhesion molecule CRTAM, while RBMECs expressed occludin, claudins 1 and 5 and CRTAM. Competing CRTAM mediated adhesion with soluble CRTAM, inhibited ReNcells CX transmigration, and at the sites of transmigration, the expression of occludin and claudin-5 diminished in RBMECs. In nude mice we found that ReNcells CX injected into systemic circulation passed the BBB and reached intracranial gliomas, which overexpressed HGF, VEGF and zonulin/prehaptoglobin 2. PMID:23637756

  15. Endothelial cell heterogeneity of blood-brain barrier gene expression along the cerebral microvasculature.

    PubMed

    Macdonald, Jennifer A; Murugesan, Nivetha; Pachter, Joel S

    2010-05-15

    The blood-brain barrier (BBB) refers to the network of microvessels that selectively restricts the passage of substances between the circulation and the central nervous system (CNS). This microvascular network is comprised of arterioles, capillaries and venules, yet the respective contribution of each of these to the BBB awaits clarification. In this regard, it has been postulated that brain microvascular endothelial cells (BMEC) from these different tributaries might exhibit considerable heterogeneity in form and function, with such diversity underlying unique roles in physiological and pathophysiological processes. Means to begin exploring such endothelial differences in situ, free from caveats associated with cell isolation and culturing procedures, are crucial to comprehending the nature and treatment of CNS diseases with vascular involvement. Here, the recently validated approach of immuno-laser capture microdissection (immuno-LCM) coupled to quantitative real-time PCR (qRT-PCR) was used to analyze gene expression patterns of BMEC retrieved in situ from either capillaries or venules. From profiling 87 genes known to play a role in BBB function and/or be enriched in isolated brain microvessels, results imply that most BBB properties reside in both segments, but that capillaries preferentially express some genes related to solute transport, while venules tend toward higher expression of an assortment of genes involved in inflammatory-related tasks. Fuller appreciation of such heterogeneity will be critical for efficient therapeutic targeting of the endothelium and the management of CNS disease. PMID:20025060

  16. MG53 permeates through blood-brain barrier to protect ischemic brain injury

    PubMed Central

    Li, Haichang; Han, Yu; Chen, Ken; Wang, Zhen; Zeng, Jing; Liu, Yukai; Wang, Xinquan; Li, Yu; He, Duofen; Lin, Peihui; Zhou, Xinyu; Park, Ki Ho; Bian, Zehua; Chen, Zhishui; Gong, Nianqiao; Tan, Tao; Zhou, Jingsong; Zhang, Meng; Ma, Jianjie; Zeng, Chunyu

    2016-01-01

    Ischemic injury to neurons represents the underlying cause of stroke to the brain. Our previous studies identified MG53 as an essential component of the cell membrane repair machinery. Here we show that the recombinant human (rh)MG53 protein facilitates repair of ischemia-reperfusion (IR) injury to the brain. MG53 rapidly moves to acute injury sites on neuronal cells to form a membrane repair patch. IR-induced brain injury increases permeability of the blood-brain-barrier, providing access of MG53 from blood circulation to target the injured brain tissues. Exogenous rhMG53 protein can protect cultured neurons against hypoxia/reoxygenation-induced damages. Transgenic mice with increased levels of MG53 in the bloodstream are resistant to IR-induced brain injury. Intravenous administration of rhMG53, either prior to or after ischemia, can effectively alleviate brain injuries in rats. rhMG53-mediated neuroprotection involves suppression of apoptotic neuronal cell death, as well as activation of the pro-survival RISK signaling pathway. Our data indicate a physiological function for MG53 in the brain and suggest that targeting membrane repair or RISK signaling may be an effective means to treat ischemic brain injury. PMID:26967557

  17. Blood-brain barrier dysfunction in disorders of the developing brain.

    PubMed

    Moretti, Raffaella; Pansiot, Julien; Bettati, Donatella; Strazielle, Nathalie; Ghersi-Egea, Jean-François; Damante, Giuseppe; Fleiss, Bobbi; Titomanlio, Luigi; Gressens, Pierre

    2015-01-01

    Disorders of the developing brain represent a major health problem. The neurological manifestations of brain lesions can range from severe clinical deficits to more subtle neurological signs or behavioral problems and learning disabilities, which often become evident many years after the initial damage. These long-term sequelae are due at least in part to central nervous system immaturity at the time of the insult. The blood-brain barrier (BBB) protects the brain and maintains homeostasis. BBB alterations are observed during both acute and chronic brain insults. After an insult, excitatory amino acid neurotransmitters are released, causing reactive oxygen species (ROS)-dependent changes in BBB permeability that allow immune cells to enter and stimulate an inflammatory response. The cytokines, chemokines and other molecules released as well as peripheral and local immune cells can activate an inflammatory cascade in the brain, leading to secondary neurodegeneration that can continue for months or even years and finally contribute to post-insult neuronal deficits. The role of the BBB in perinatal disorders is poorly understood. The inflammatory response, which can be either acute (e.g., perinatal stroke, traumatic brain injury) or chronic (e.g., perinatal infectious diseases) actively modulates the pathophysiological processes underlying brain injury. We present an overview of current knowledge about BBB dysfunction in the developing brain during acute and chronic insults, along with clinical and experimental data. PMID:25741233

  18. Scutellaria baicalensis attenuates blood-brain barrier disruption after intracerebral hemorrhage in rats.

    PubMed

    Shin, Jung-Won; Kang, Ho-Chang; Shim, Jaewon; Sohn, Nak-Won

    2012-01-01

    Disruption of the blood-brain barrier (BBB) contributes to the inflammatory response and edema formation in the brain, exacerbating brain damage. The present study evaluated the effects of Scutellaria baicalensis (SR) water extracts on BBB disruption after intracerebral hemorrhage (ICH) in rats. ICH was induced by stereotaxic intrastriatal injection of bacterial type VII collagenase, and SR was administrated orally three times (50 mg/ml/kg) during the 48 h after ICH onset. SR treatment significantly reduced the degree of (1) hemorrhage volume and edema percentage of the ipsilateral hemisphere, (2) brain water content, (3) MPO-positive neutrophil infiltration in the peri-hematoma, and (4) BBB permeability measured by Evans blue leakage. In addition, expression of matrix metalloproteinase (MMP)-9, MMP-12, and tissue inhibitor of MMPs (TIMP)-1 were investigated with immunohistochemistry. SR treatment reduced MMP-9 and MMP-12 expression in the peri-hematoma after ICH. These results indicate that SR attenuates the BBB disruption through anti-inflammatory effects and suppression of MMP expression. These findings provide a pharmacological basis for the use of SR in the treatment of the BBB disruption following stroke and trauma. PMID:22298450

  19. Central role for PICALM in amyloid-β blood-brain barrier transcytosis and clearance.

    PubMed

    Zhao, Zhen; Sagare, Abhay P; Ma, Qingyi; Halliday, Matthew R; Kong, Pan; Kisler, Kassandra; Winkler, Ethan A; Ramanathan, Anita; Kanekiyo, Takahisa; Bu, Guojun; Owens, Nelly Chuqui; Rege, Sanket V; Si, Gabriel; Ahuja, Ashim; Zhu, Donghui; Miller, Carol A; Schneider, Julie A; Maeda, Manami; Maeda, Takahiro; Sugawara, Tohru; Ichida, Justin K; Zlokovic, Berislav V

    2015-07-01

    PICALM is a highly validated genetic risk factor for Alzheimer's disease (AD). We found that reduced expression of PICALM in AD and murine brain endothelium correlated with amyloid-β (Aβ) pathology and cognitive impairment. Moreover, Picalm deficiency diminished Aβ clearance across the murine blood-brain barrier (BBB) and accelerated Aβ pathology in a manner that was reversible by endothelial PICALM re-expression. Using human brain endothelial monolayers, we found that PICALM regulated PICALM/clathrin-dependent internalization of Aβ bound to the low density lipoprotein receptor related protein-1, a key Aβ clearance receptor, and guided Aβ trafficking to Rab5 and Rab11, leading to Aβ endothelial transcytosis and clearance. PICALM levels and Aβ clearance were reduced in AD-derived endothelial monolayers, which was reversible by adenoviral-mediated PICALM transfer. Inducible pluripotent stem cell-derived human endothelial cells carrying the rs3851179 protective allele exhibited higher PICALM levels and enhanced Aβ clearance. Thus, PICALM regulates Aβ BBB transcytosis and clearance, which has implications for Aβ brain homeostasis and clearance therapy. PMID:26005850

  20. SEMA4D compromises blood-brain barrier, activates microglia, and inhibits remyelination in neurodegenerative disease.

    PubMed

    Smith, Ernest S; Jonason, Alan; Reilly, Christine; Veeraraghavan, Janaki; Fisher, Terrence; Doherty, Michael; Klimatcheva, Ekaterina; Mallow, Crystal; Cornelius, Chad; Leonard, John E; Marchi, Nicola; Janigro, Damir; Argaw, Azeb Tadesse; Pham, Trinh; Seils, Jennifer; Bussler, Holm; Torno, Sebold; Kirk, Renee; Howell, Alan; Evans, Elizabeth E; Paris, Mark; Bowers, William J; John, Gareth; Zauderer, Maurice

    2015-01-01

    Multiple sclerosis (MS) is a chronic neuroinflammatory disease characterized by immune cell infiltration of CNS, blood-brain barrier (BBB) breakdown, localized myelin destruction, and progressive neuronal degeneration. There exists a significant need to identify novel therapeutic targets and strategies that effectively and safely disrupt and even reverse disease pathophysiology. Signaling cascades initiated by semaphorin 4D (SEMA4D) induce glial activation, neuronal process collapse, inhibit migration and differentiation of oligodendrocyte precursor cells (OPCs), and disrupt endothelial tight junctions forming the BBB. To target SEMA4D, we generated a monoclonal antibody that recognizes mouse, rat, monkey and human SEMA4D with high affinity and blocks interaction between SEMA4D and its cognate receptors. In vitro, anti-SEMA4D reverses the inhibitory effects of recombinant SEMA4D on OPC survival and differentiation. In vivo, anti-SEMA4D significantly attenuates experimental autoimmune encephalomyelitis in multiple rodent models by preserving BBB integrity and axonal myelination and can be shown to promote migration of OPC to the site of lesions and improve myelin status following chemically-induced demyelination. Our study underscores SEMA4D as a key factor in CNS disease and supports the further development of antibody-based inhibition of SEMA4D as a novel therapeutic strategy for MS and other neurologic diseases with evidence of demyelination and/or compromise to the neurovascular unit. PMID:25461192

  1. Pyruvate blocks blood-brain barrier disruption, lymphocyte infiltration and immune response in excitotoxic brain injury

    PubMed Central

    Ryu, Jae K; McLarnon, James G

    2016-01-01

    The effects of pyruvate, the end metabolite of glycolysis, on blood-brain barrier (BBB) impairment and immune reactivity were examined in the quinolinic acid (QA)-injected rat striatum. Extensive disruption of BBB was observed at 7 d post QA-injection as demonstrated by increased immunohistochemical staining using antibody against immunoglobulin G (IgG). Animals receiving pyruvate administration (500 mg/kg) with QA-injection exhibited reduced lgG immunoreactivity (by 45%) relative to QA alone. QA intrastriatal injection also resulted in marked increases in the number of infiltrating T-lymphocytes (by 70-fold) and expression of major histocompatibility complex (MHC-class II) (by 45-fold) relative to unlesioned control. Treatment with pyruvate significantly reduced infiltration of T-cells (by 68%) and MHC class II expression (by 48%) induced by QA. These results indicate that QA injection into rat striatum leads to impairment in BBB function with pyruvate administration reducing immune response and BBB leakiness in excitotoxic injury. PMID:27073744

  2. Transporter protein and drug-conjugated gold nanoparticles capable of bypassing the blood-brain barrier

    PubMed Central

    Zhang, Yanhua; Walker, Janelle Buttry; Minic, Zeljka; Liu, Fangchao; Goshgarian, Harry; Mao, Guangzhao

    2016-01-01

    Drug delivery to the central nervous system (CNS) is challenging due to the inability of many drugs to cross the blood-brain barrier (BBB). Here, we show that wheat germ agglutinin horse radish peroxidase (WGA-HRP) chemically conjugated to gold nanoparticles (AuNPs) can be transported to the spinal cord and brainstem following intramuscular injection into the diaphragm of rats. We synthesized and determined the size and chemical composition of a three-part nanoconjugate consisting of WGA-HRP, AuNPs, and drugs for the treatment of diaphragm paralysis associated with high cervical spinal cord injury (SCI). Upon injection into the diaphragm muscle of rats, we show that the nanoconjugate is capable of delivering the drug at a much lower dose than the unconjugated drug injected systemically to effectively induce respiratory recovery in rats following SCI. This study not only demonstrates a promising strategy to deliver drugs to the CNS bypassing the BBB but also contributes a potential nanotherapy for the treatment of respiratory muscle paralysis resulted from cervical SCI. PMID:27180729

  3. Leptin transport across the blood-brain barrier: implications for the cause and treatment of obesity.

    PubMed

    Banks, W A

    2001-01-01

    Leptin has emerged as a major regulator of adiposity. Leptin is released into the blood from fat cells and circulates to the brain where it crosses the blood-brain barrier (BBB) to act at receptors within the central nervous system to affect appetite, thermogenesis, and a number of other actions. In humans and in many rodent models, resistance to leptin appears to be a chief cause of obesity. Determining the cause of leptin resistance is fundamental to developing strategies for the use of leptin in obesity. The literature characterizing the transport of leptin across the BBB is reviewed. This literature strongly suggests that the cause of leptin resistance is due a decreased transport of leptin across the BBB in obese humans and rodents. The main cause of this resistance appears to be an impairment in the activity of the transporter rather than just simply saturation at higher doses. Strategies to overcome impaired BBB transport are reviewed, including the use of allosteric regulators and the delivery of material by the intrathecal route. PMID:11172704

  4. Blood brain barrier is impermeable to solutes and permeable to water after experimental pediatric cardiac arrest.

    PubMed

    Tress, Erika E; Clark, Robert S B; Foley, Lesley M; Alexander, Henry; Hickey, Robert W; Drabek, Tomas; Kochanek, Patrick M; Manole, Mioara D

    2014-08-22

    Pediatric asphyxial cardiac arrest (CA) results in unfavorable neurological outcome in most survivors. Development of neuroprotective therapies is contingent upon understanding the permeability of intravenously delivered medications through the blood brain barrier (BBB). In a model of pediatric CA we sought to characterize BBB permeability to small and large molecular weight substances. Additionally, we measured the percent brain water after CA. Asphyxia of 9 min was induced in 16-18 day-old rats. The rats were resuscitated and the BBB permeability to small (sodium fluorescein and gadoteridol) and large (immunoglobulin G, IgG) molecules was assessed at 1, 4, and 24 h after asphyxial CA or sham surgery. Percent brain water was measured post-CA and in shams using wet-to-dry brain weight. Fluorescence, gadoteridol uptake, or IgG staining at 1, 4h and over the entire 24 h post-CA did not differ from shams, suggesting absence of BBB permeability to these solutes. Cerebral water content was increased at 3h post-CA vs. sham. In conclusion, after 9 min of asphyxial CA there is no BBB permeability over 24h to conventional small or large molecule tracers despite the fact that cerebral water content is increased early post-CA indicating the development of brain edema. Evaluation of novel therapies targeting neuronal death after pediatric CA should include their capacity to cross the BBB. PMID:24937271

  5. Effects of GSM modulated radio-frequency electromagnetic radiation on permeability of blood-brain barrier in male & female rats.

    PubMed

    Sırav, Bahriye; Seyhan, Nesrin

    2016-09-01

    With the increased use of mobile phones, their biological and health effects have become more important. Usage of mobile phones near the head increases the possibility of effects on brain tissue. This study was designed to investigate the possible effects of pulse modulated 900MHz and 1800MHz radio-frequency radiation on the permeability of blood-brain barrier of rats. Study was performed with 6 groups of young adult male and female wistar albino rats. The permeability of blood-brain barrier to intravenously injected evans blue dye was quantitatively examined for both control and radio-frequency radiarion exposed groups. For male groups; Evans blue content in the whole brain was found to be 0.08±0.01mg% in the control, 0.13±0.03mg% in 900MHz exposed and 0.26±0.05mg% in 1800MHz exposed animals. In both male radio-frequency radiation exposed groups, the permeability of blood-brain barrier found to be increased with respect to the controls (p<0.01). 1800MHz pulse modulated radio-frequency radiation exposure was found more effective on the male animals (p<0.01). For female groups; dye contents in the whole brains were 0.14±0.01mg% in the control, 0.24±0.03mg% in 900MHz exposed and 0.14±0.02mg% in 1800MHz exposed animals. No statistical variance found between the control and 1800MHz exposed animals (p>0.01). However 900MHz pulse modulated radio-frequency exposure was found effective on the permeability of blood-brain barrier of female animals. Results have shown that 20min pulse modulated radio-frequency radiation exposure of 900MHz and 1800MHz induces an effect and increases the permeability of blood-brain barrier of male rats. For females, 900MHz was found effective and it could be concluded that this result may due to the physiological differences between female and male animals. The results of this study suggest that mobile phone radation could lead to increase the permeability of blood-brain barrier under non-thermal exposure levels. More studies are needed

  6. Noninvasive delivery of stealth, brain-penetrating nanoparticles across the blood-brain barrier using MRI-guided focused ultrasound

    PubMed Central

    Miller, G. Wilson; Song, Ji; Louttit, Cameron; Klibanov, Alexander L; Shih, Ting-Yu; Swaminathan, Ganesh; Tamargo, Rafael J.; Woodworth, Graeme F.; Hanes, Justin; Price, Richard J.

    2014-01-01

    The blood-brain barrier (BBB) presents a significant obstacle for the treatment of many central nervous system (CNS) disorders, including invasive brain tumors, Alzheimer’s, Parkinson’s and stroke. Therapeutics must be capable of bypassing the BBB and also penetrate the brain parenchyma to achieve a desired effect within the brain. In this study, we test the unique combination of a noninvasive approach to BBB permeabilization with a therapeutically relevant polymeric nanoparticle platform capable of rapidly penetrating within the brain microenvironment. MR-guided focused ultrasound (FUS) with intravascular microbubbles (MBs) is able to locally and reversibly disrupt the BBB with submillimeter spatial accuracy. Densely poly(ethylene-co-glycol) (PEG) coated, brain-penetrating nanoparticles (BPNs) are long-circulating and diffuse 10-fold slower in normal rat brain tissue compared to diffusion in water. Following intravenous administration of model and biodegradable BPN in normal healthy rats, we demonstrate safe, pressure-dependent delivery of 60 nm BPNs to the brain parenchyma in regions where the BBB is disrupted by FUS and MBs. Delivery of BPNs with MR-guided FUS has the potential to improve efficacy of treatments for many CNS diseases, while reducing systemic side effects by providing sustained, well-dispersed drug delivery into select regions of the brain. PMID:24979210

  7. Delivery of doxorubicin across the blood-brain barrier by ondansetron pretreatment: a study in vitro and in vivo.

    PubMed

    Sardi, Iacopo; Fantappiè, Ornella; la Marca, Giancarlo; Giovannini, Maria Grazia; Iorio, Anna Lisa; da Ros, Martina; Malvagia, Sabrina; Cardellicchio, Stefania; Giunti, Laura; de Martino, Maurizio; Mazzanti, Roberto

    2014-10-28

    Doxorubicin (Dox) has got a limited efficacy in the treatment of central nervous system tumors because of its poor penetration through blood-brain barrier mediated by MDR efflux transporters. We investigated the possibility that ondansetron (Ond) enhances Dox cytotoxicity in cell lines interfering with P-glycoprotein and increases Dox concentration in rat brain tissues. The MDR phenotype was studied using human hepatocellular carcinoma cell line PLC/PRF/5 (P5 and P1(0.5) clones), two subclones of NIH 3T3 cells (PSI-2 and PN1A) and two glioblastoma cell lines (A172, U87MG). Rats were pretreated with Ond before injection of Dox. Quantitative analysis of Dox was performed by mass spectrometry. Our in vitro experiments demonstrated that Ond at 10 µg/ml is not toxic to all cell lines. However, Ond reverses the MDR phenotype in P1(0.5) and PN1A cell lines. In addition, we showed that pretreatment with Ond increases Dox concentration in rat brain tissues, without increasing acute heart and renal toxicity. PMID:25079687

  8. A2A adenosine receptor modulates drug efflux transporter P-glycoprotein at the blood-brain barrier

    PubMed Central

    Kim, Do-Geun; Bynoe, Margaret S.

    2016-01-01

    The blood-brain barrier (BBB) protects the brain from toxic substances within the peripheral circulation. It maintains brain homeostasis and is a hurdle for drug delivery to the CNS to treat neurodegenerative diseases, including Alzheimer’s disease and brain tumors. The drug efflux transporter P-glycoprotein (P-gp) is highly expressed on brain endothelial cells and blocks the entry of most drugs delivered to the brain. Here, we show that activation of the A2A adenosine receptor (AR) with an FDA-approved A2A AR agonist (Lexiscan) rapidly and potently decreased P-gp expression and function in a time-dependent and reversible manner. We demonstrate that downmodulation of P-gp expression and function coincided with chemotherapeutic drug accumulation in brains of WT mice and in primary mouse and human brain endothelial cells, which serve as in vitro BBB models. Lexiscan also potently downregulated the expression of BCRP1, an efflux transporter that is highly expressed in the CNS vasculature and other tissues. Finally, we determined that multiple pathways, including MMP9 cleavage and ubiquitinylation, mediated P-gp downmodulation. Based on these data, we propose that A2A AR activation on BBB endothelial cells offers a therapeutic window that can be fine-tuned for drug delivery to the brain and has potential as a CNS drug-delivery technology. PMID:27043281

  9. Amyloid Triggers Extensive Cerebral Angiogenesis Causing Blood Brain Barrier Permeability and Hypervascularity in Alzheimer's Disease

    PubMed Central

    Biron, Kaan E.; Dickstein, Dara L.; Gopaul, Rayshad; Jefferies, Wilfred A.

    2011-01-01

    Evidence of reduced blood-brain barrier (BBB) integrity preceding other Alzheimer's disease (AD) pathology provides a strong link between cerebrovascular angiopathy and AD. However, the “Vascular hypothesis”, holds that BBB leakiness in AD is likely due to hypoxia and neuroinflammation leading to vascular deterioration and apoptosis. We propose an alternative hypothesis: amyloidogenesis promotes extensive neoangiogenesis leading to increased vascular permeability and subsequent hypervascularization in AD. Cerebrovascular integrity was characterized in Tg2576 AD model mice that overexpress the human amyloid precursor protein (APP) containing the double missense mutations, APPsw, found in a Swedish family, that causes early-onset AD. The expression of tight junction (TJ) proteins, occludin and ZO-1, were examined in conjunction with markers of apoptosis and angiogenesis. In aged Tg2576 AD mice, a significant increase in the incidence of disrupted TJs, compared to age matched wild-type littermates and young mice of both genotypes, was directly linked to an increased microvascular density but not apoptosis, which strongly supports amyloidogenic triggered hypervascularity as the basis for BBB disruption. Hypervascularity in human patients was corroborated in a comparison of postmortem brain tissues from AD and controls. Our results demonstrate that amylodogenesis mediates BBB disruption and leakiness through promoting neoangiogenesis and hypervascularity, resulting in the redistribution of TJs that maintain the barrier and thus, provides a new paradigm for integrating vascular remodeling with the pathophysiology observed in AD. Thus the extensive angiogenesis identified in AD brain, exhibits parallels to the neovascularity evident in the pathophysiology of other diseases such as age-related macular degeneration. PMID:21909359

  10. Effects of ionizing radiation on the blood brain barrier permeability to pharmacologically active substances

    SciTech Connect

    Trnovec, T.; Kallay, Z.; Bezek, S. )

    1990-12-01

    Ionizing radiation can impair the integrity of the blood brain barrier (BBB). Data on early and late damage after brain irradiation are usually reported separately, yet a gradual transition between these two types has become evident. Signs appearing within 3 weeks after irradiation are considered to be early manifestations. The mechanism of radiation-effected integrity impairment of the BBB is discussed in relation to changes in morphological structures forming the BBB, the endothelium of intracerebral vessels, and in the surrounding astrocytes. Alterations in the function of the BBB are manifested in the endothelium by changes in the ultrastructural location of the activity of phosphatases and by the activation of pinocytotic vesicular transport, and in astrocyte cytoplasm by glycogen deposition. The changes in ultrastructure were critically surveyed with regard to increasing doses of radiation to the brain in the range of 5 Gy to 960 Gy. The qualitative as well as the semiquantitative and quantitative observations on the passage of substances across the damaged BBB were treated separately. Qualitative changes are based mainly on findings of extravasation of vital stains and of labelled proteins. The quantitative studies established differences in radiation-induced changes in the permeability of the BBB depending on the structure and physico-chemical properties of the barrier penetrating tracers. Indirect evaluation of radiation-induced BBB changes is based on studies of pharmacological effects of substances acting on the CNS. In conclusion, radiation impairs significantly the integrity of the BBB following single irradiation of the brain with a dose exceeding 10-15 Gy. The response of the BBB to ionizing radiation is dependent both on the dose to which the brain is exposed and on specific properties of the tracer. 68 references.

  11. Enhanced blood-brain barrier transmigration using a novel transferrin embedded fluorescent magneto-liposome nanoformulation

    NASA Astrophysics Data System (ADS)

    Ding, Hong; Sagar, Vidya; Agudelo, Marisela; Pilakka-Kanthikeel, Sudheesh; Subba Rao Atluri, Venkata; Raymond, Andrea; Samikkannu, Thangavel; Nair, Madhavan P.

    2014-02-01

    The blood-brain barrier (BBB) is considered as the primary impediment barrier for most drugs. Delivering therapeutic agents to the brain is still a big challenge to date. In our study, a dual mechanism, receptor mediation combined with external non-invasive magnetic force, was incorporated into ferrous magnet-based liposomes for BBB transmigration enhancement. The homogenous magnetic nanoparticles (MNPs), with a size of ˜10 nm, were synthesized and confirmed by TEM and XRD respectively. The classical magnetism assay showed the presence of the characteristic superparamagnetic property. These MNPs encapsulated in PEGylated fluorescent liposomes as magneto-liposomes (MLs) showed mono-dispersion, ˜130 ± 10 nm diameter, by dynamic laser scattering (DLS) using the lipid-extrusion technique. Remarkably, a magnetite encapsulation efficiency of nearly 60% was achieved. Moreover, the luminescence and hydrodynamic size of the MLs was stable for over two months at 4 ° C. Additionally, the integrity of the ML structure remained unaffected through 120 rounds of circulation mimicking human blood fluid. After biocompatibility confirmation by cytotoxicity evaluation, these fluorescent MLs were further embedded with transferrin and applied to an in vitro BBB transmigration study in the presence or absence of external magnetic force. Comparing with magnetic force- or transferrin receptor-mediated transportation alone, their synergy resulted in 50-100% increased transmigration without affecting the BBB integrity. Consequently, confocal microscopy and iron concentration in BBB-composed cells further confirmed the higher cellular uptake of ML particles due to the synergic effect. Thus, our multifunctional liposomal magnetic nanocarriers possess great potential in particle transmigration across the BBB and may have a bright future in drug delivery to the brain.

  12. Surfactants, not size or zeta-potential influence blood-brain barrier passage of polymeric nanoparticles.

    PubMed

    Voigt, Nadine; Henrich-Noack, Petra; Kockentiedt, Sarah; Hintz, Werner; Tomas, Jürgen; Sabel, Bernhard A

    2014-05-01

    Nanoparticles (NP) can deliver drugs across the blood-brain barrier (BBB), but little is known which of the factors surfactant, size and zeta-potential are essential for allowing BBB passage. To this end we designed purpose-built fluorescent polybutylcyanoacrylate (PBCA) NP and imaged the NP's passage over the blood-retina barrier - which is a model of the BBB - in live animals. Rats received intravenous injections of fluorescent PBCA-NP fabricated by mini-emulsion polymerisation to obtain various NP's compositions that varied in surfactants (non-ionic, anionic, cationic), size (67-464nm) and zeta-potential. Real-time imaging of retinal blood vessels and retinal tissue was carried out with in vivo confocal neuroimaging (ICON) before, during and after NP's injection. Successful BBB passage with subsequent cellular labelling was achieved if NP were fabricated with non-ionic surfactants or cationic stabilizers but not when anionic compounds were added. NP's size and charge had no influence on BBB passage and cell labelling. This transport was not caused by an unspecific opening of the BBB because control experiments with injections of unlabelled NP and fluorescent dye (to test a "door-opener" effect) did not lead to parenchymal labelling. Thus, neither NP's size nor chemo-electric charge, but particle surface is the key factor determining BBB passage. This result has important implications for NP engineering in medicine: depending on the surfactant, NP can serve one of two opposite functions: while non-ionic tensides enhance brain up-take, addition of anionic tensides prevents it. NP can now be designed to specifically enhance drug delivery to the brain or, alternatively, to prevent brain penetration so to reduce unwanted psychoactive effects of drugs or prevent environmental nanoparticles from entering tissue of the central nervous system. PMID:24607790

  13. Blood-Brain Barrier Experiments with Clinical Magnetic Resonance Imaging and an Immunohistochemical Study

    PubMed Central

    Park, Jun Woo; Kim, Hak Jin; Han, Hyung Soo

    2010-01-01

    Objective The purpose of study was to evaluate the feasibility of brain magnetic resonance (MR) images of the rat obtained using a 1.5T MR machine in several blood-brain barrier (BBB) experiments. Methods Male Sprague-Dawley rats were used. MR images were obtained using a clinical 1.5T MR machine. A microcatheter was introduced via the femoral artery to the carotid artery. Normal saline (group 1, n = 4), clotted autologous blood (group 2, n = 4), triolein emulsion (group 3, n = 4), and oleic acid emulsion (group 4, n = 4) were infused into the carotid artery through a microcatheter. Conventional and diffusion-weighted images, the apparent coefficient map, perfusion-weighted images, and contrast-enhanced MR images were obtained. Brain tissue was obtained and triphenyltetrazolium chloride (TTC) staining was performed in group 2. Fluorescein isothiocyanate (FITC)-labeled dextran images and endothelial barrier antigen (EBA) studies were performed in group 4. Results The MR images in group 1 were of good quality. The MR images in group 2 revealed typical findings of acute cerebral infarction. Perfusion defects were noted on the perfusion-weighted images. The MR images in group 3 showed vasogenic edema and contrast enhancement, representing vascular damage. The rats in group 4 had vasogenic edema on the MR images and leakage of dextran on the FITC-labeled dextran image, representing increased vascular permeability. The immune reaction was decreased on the EBA study. Conclusion Clinical 1.5T MR images using a rat depicted many informative results in the present study. These results can be used in further researches of the BBB using combined clinical MR machines and immunohistochemical examinations. PMID:20379473

  14. Glycodermorphins: opioid peptides with potent and prolonged analgesic activity and enhanced blood-brain barrier penetration.

    PubMed

    Negri, L; Lattanzi, R; Tabacco, F; Scolaro, B; Rocchi, R

    1998-08-01

    1. In order to improve the in vivo stability of the opioid peptide dermorphin we synthesized O-betaglucosylated analogs ([Ser7-O-betaGlc]dermorphin and [Ser7-O-betaGlc(Ac)4]-dermorphin) and C-alphagalactosylated analogs ([Ala7-C-alphaGal]dermorphin and [Ala7-C-alphaGal(Ac)4]-dermorphin). 2. O- and C-glycosylation of dermorphin halved the peptide affinity for brain mu-opioid receptors and the biological potency in guinea-pig ileum assay (GPI). Despite their lower opioid receptor affinity, when administered intracerebroventricularly (i.c.v., 8-40 pmol) and subcutaneously (s.c., 0.5-3 micromol kg(-1)) in rats, glycosylated analogs were two times more potent than dermorphin in reducing the nociceptive response to radiant heat. Acetylation of sugar hydroxyl groups reduces 5-10 times both biological activity on GPI and mu-receptor affinity, whereas the antinociceptive potency was equal to (i.c.v.) or only two-three times lower (s.c.) than dermorphin potency. 3. Blood-Brain Barrier Permeability Index (BBB-PI) of the glycodermorphins was significantly higher than that of dermorphin, indicating a facilitated entry into the brain: O-beta-linked glucoconiugates are expected to enter CNS by the glucose transporter GLUT-1 of the endothelial barrier. However the calculated BBB-PI for the C-alphagalactoside was about two times higher than that of the O-betaglucoside, excluding the implication of GLUT-1 that is known to be selective for O-beta-links and preferring for the exose glucose. 4. The enhanced brain permeability with the subsequent decrease in peripheral dosage of these opioid peptides did not result in lowering constipation. PMID:9723966

  15. Control of the blood-brain barrier function in cancer cell metastasis.

    PubMed

    Blecharz, Kinga G; Colla, Ruben; Rohde, Veit; Vajkoczy, Peter

    2015-10-01

    Cerebral metastases are the most common brain neoplasms seen clinically in the adults and comprise more than half of all brain tumours. Actual treatment options for brain metastases that include surgical resection, radiotherapy and chemotherapy are rarely curative, although palliative treatment improves survival and life quality of patients carrying brain-metastatic tumours. Chemotherapy in particular has also shown limited or no activity in brain metastasis of most tumour types. Many chemotherapeutic agents used systemically do not cross the blood-brain barrier (BBB), whereas others may transiently weaken the BBB and allow extravasation of tumour cells from the circulation into the brain parenchyma. Increasing evidence points out that the interaction between the BBB and tumour cells plays a key role for implantation and growth of brain metastases in the central nervous system. The BBB, as the tightest endothelial barrier, prevents both early detection and treatment by creating a privileged microenvironment. Therefore, as observed in several in vivo studies, precise targetting the BBB by a specific transient opening of the structure making it permeable for therapeutic compounds, might potentially help to overcome this difficult clinical problem. Moreover, a better understanding of the molecular features of the BBB, its interrelation with metastatic tumour cells and the elucidation of cellular mechanisms responsible for establishing cerebral metastasis must be clearly outlined in order to promote treatment modalities that particularly involve chemotherapy. This in turn would substantially expand the survival and quality of life of patients with brain metastasis, and potentially increase the remission rate. Therefore, the focus of this review is to summarise the current knowledge on the role and function of the BBB in cancer metastasis. PMID:26032862

  16. The Blood-brain Barrier in Neuroimmunology: Tales of Separation and Assimilation

    PubMed Central

    Banks, W. A.

    2014-01-01

    Neuroimmunology is concerned with the relations between the central nervous and immune systems and with the mechanisms that drive those relations. The blood-brain barrier (BBB) employs mechanisms that both separate and connect these two systems. In fact, the relative immune privilege of the central nervous system (CNS) is largely attributable to the BBB's ability to prevent the unregulated exchange of immune cells and their secretions between the CNS and blood. Having separated the two systems, the BBB then participates in mechanisms that allow them to influence, communicate, and interact with one another. Likewise, the BBB itself is influenced by immune events that are occurring in the periphery and in the CNS so that these three components (the BBB, the immune system, and the CNS) form neuroimmune axes that adapt to physiological and pathological conditions. To date, four major themes have emerged by which the BBB participates in these neuroimmune axes. The first of these four, the formation of the barrier, acts to separate the immune and central nervous systems. The other three themes provide mechanisms for re-establishing communication: response of the BBB to immunomodulatory molecules (e.g., prostaglandins, cytokines, chemokines, nitric oxide) secreted by immune and CNS cells; the controlled, regulated exchange of chemokines, cytokines, and immune cells between the CNS and the blood (i.e., transport across the BBB); the secretion of immunomodulatory molecules by the BBB, often in a polarized fashion. Taken together, these mechanisms reveal the BBB to be a dynamic, interactive, and adaptable interface between the immune system and the CNS, separating them on the one hand and fostering their interaction on the other hand, adjusting to physiological changes, while being a target for disease processes. This review examines specific examples by which the BBB plays an interactive, defining role in neuroimmunology. PMID:25172555

  17. Permeability of the blood-brain barrier depends on brain temperature

    PubMed Central

    Kiyatkin, Eugene A.; Sharma, Hari S.

    2009-01-01

    Increased permeability of the blood-brain barrier (BBB) has been reported in different conditions accompanied by hyperthermia, but the role of brain temperature per se in modulating brain barrier functions has not been directly examined. To delineate the contribution of this factor, we examined albumin immunoreactivity in several brain structures (cortex, hippocampus, thalamus and hypothalamus) of pentobarbital-anesthetized rats (50 mg/kg, ip), which were passively warmed to different levels of brain temperature (32–42°C). Similar brain structures were also examined for the expression of glial fibrillary acidic protein (GFAP), an index of astrocytic activation, water and ion content, and morphological cell abnormalities. Data were compared with those obtained from drug-free awake rats with normal brain temperatures (36–37°C). The numbers of albumin- and GFAP-positive cells strongly correlates with brain temperature, gradually increasing from ~38.5°C and plateauing at 41–42°C. Brains maintained at hyperthermia also showed larger content of brain water and Na+, K+ and Cl− as well as structural abnormalities of brain cells, all suggesting acute brain edema. The latter alterations were seen at ~39°C, gradually progressed with temperature increase, and peaked at maximum hyperthermia. Temperature-dependent changes in albumin immunoreactivity tightly correlated with GFAP immunoreactivity, brain water, and numbers of abnormal cells; they were found in each tested area, but showed some structural specificity. Notably, a mild BBB leakage, selective glial activation, and specific cellular abnormalities were also found in the hypothalamus and piriform cortex during extreme hypothermia (32–33°C); in contrast to hyperthermia these changes were associated with decreased levels of brain water, Na+ and K+, suggesting acute brain dehydration. Therefore, brain temperature per se is an important factor in regulating BBB permeability, alterations in brain water

  18. Disruption of the blood-brain barrier in pigs naturally infected with Taenia solium, untreated and after anthelmintic treatment.

    PubMed

    Guerra-Giraldez, Cristina; Marzal, Miguel; Cangalaya, Carla; Balboa, Diana; Orrego, Miguel Ángel; Paredes, Adriana; Gonzales-Gustavson, Eloy; Arroyo, Gianfranco; García, Hector H; González, Armando E; Mahanty, Siddhartha; Nash, Theodore E

    2013-08-01

    Neurocysticercosis is a widely prevalent disease in the tropics that causes seizures and a variety into of neurological symptoms in most of the world. Experimental models are limited and do not allow assessment of the degree of inflammation around brain cysts. The vital dye Evans Blue (EB) was injected to 11 pigs naturally infected with Taenia solium cysts to visually identify the extent of disruption of the blood-brain barrier. A total of 369 cysts were recovered from the 11 brains and classified according to the staining of their capsules as blue or unstained. The proportion of cysts with blue capsules was significantly higher in brains from pigs that had received anthelmintic treatment 48 and 120h before the EB infusion, indicating a greater compromise of the blood-brain barrier due to treatment. The model could be useful for understanding the pathology of treatment-induced inflammation in neurocysticercosis. PMID:23684909

  19. ST6GALNAC5 Expression Decreases the Interactions between Breast Cancer Cells and the Human Blood-Brain Barrier

    PubMed Central

    Drolez, Aurore; Vandenhaute, Elodie; Delannoy, Clément Philippe; Dewald, Justine Hélène; Gosselet, Fabien; Cecchelli, Romeo; Julien, Sylvain; Dehouck, Marie-Pierre; Delannoy, Philippe; Mysiorek, Caroline

    2016-01-01

    The ST6GALNAC5 gene that encodes an α2,6-sialyltransferase involved in the biosynthesis of α-series gangliosides, was previously identified as one of the genes that mediate breast cancer metastasis to the brain. We have shown that the expression of ST6GALNAC5 in MDA-MB-231 breast cancer cells resulted in the expression of GD1α ganglioside at the cell surface. By using a human blood-brain barrier in vitro model recently developed, consisting in CD34+ derived endothelial cells co-cultivated with pericytes, we show that ST6GALNAC5 expression decreased the interactions between the breast cancer cells and the human blood-brain barrier. PMID:27529215

  20. Permeability changes in the blood-brain barrier: causes and consequences.

    PubMed

    Pardridge, W M; Connor, J D; Crawford, I L

    1975-01-01

    1. Generalized changes in blood-brain barrier (BBB) permeability are accompanied by extravasation of plasma proteins; thus, they are readily studied with protein markers or protein-dye complexes. Selective changes in permeability involve alterations in BBB transport systems; they are best studied with techniques which detect the qualitative hallmarks of carrier-mediated transport, namely saturation, competition, and stereospecificity. 2. Quantitative assessments of the selective permeability of the BBB can be made from the saturation data expressed in terms of Michaelis-Menten kinetics. The advantages of the latter are twofold: (a) alterations elicited by modified barrier affinity (Km) can be distinguished from alterations in carrier capacity (Vmax); (b) the relative rates of flux of a metabolite across the BBB can be placed in the perspective of cerebral metabolism. Kinetic data on transport processes in the BBB are obtained by either constant infusion or single injection techniques. Results obtained with both methodologies have been comparable. 3. Independent transport systems for glucose, neutral amino acids, basic amino acids, and monocarboxylic acids have been identified in the BBB. The description of these transport systems in kinetic terms provides a background of information on intact mechanisms to which altered transport can be compared. 4. Experimental evidence indicates that the availability of key metabolic substrates, such as glucose or essential amino acids, may be rate-limiting in cerebral metabolism. A working hypothesis was developed that the consequences of a selective change in barrier permeability to one or more of these essential substrates are directly related to altered rates of reaction in substrate-limited pathways, e.g., cerebral protein or neuro-transmitter biosynthesis. 5. Toxicological causes of generalized changes in BBB permeability include hypertonic solutions, organic solvents, surface-active agents, enzymes, and heavy metals. Some

  1. A novel strategy to monitor microfluidic in-vitro blood-brain barrier models using impedance spectroscopy

    NASA Astrophysics Data System (ADS)

    Yeste, J.; Illa, X.; Guimerà, A.; Villa, R.

    2015-06-01

    In this work, we present the use of interdigitated electrodes (IDEs) for performing electrical impedance spectroscopy (EIS) measurements to monitor a microfluidic blood brain barrier model. In particular, an electrode configuration which would not impair the optical visualization of the cell culture is proposed. Numerical studies have been performed to evaluate the electrical impedance sensitivity of the proposed tetrapolar configuration along the cell barrier in a given microfluidic chamber geometry. The system has been validated using a home-made cyclo olefin polymer (COP) bioreactor and perforated poly (methyl methacrylate) (PMMA) sheets with different pore densities in order to simulate different cell barrier impedances.

  2. Evaluation of blood--brain barrier permeability changes in rhesus monkeys and man using /sup 82/Rb and positron emission tomography

    SciTech Connect

    Yen, C.K.; Budinger, T.F.

    1981-12-01

    Dynamic positron tomography of the brain with /sup 82/Rb, obtained from a portable generator (/sup 82/Sr (25 days) -- /sup 82/Rb (76 sec)), provides a means of studying blood-brain barrier (BBB) permeability in physiological and clinical investigations. The BBB in rhesus monkeys was opened unilaterally by intracarotid infusion of 3 M urea. This osmotic barrier opening allowed entry into the brain of intravenously administered rubidium chloride. The BBB opening was demonstrated noninvasively using /sup 82/Rb and positron emission tomography and corroborated by the accumulation of /sup 86/Rb in tissue samples. Positron emission tomography studies can be repeated every 5 min and indicate that dynamic tomography or static imaging can be used to study BBB permeability changes induced by a wide variety of noxious stimuli. Brain tumors in human subjects are readily detected because of the usual BBB permeability disruption in and around the tumors.

  3. Preparation of Silica Nanoparticles Loaded with Nootropics and Their In Vivo Permeation through Blood-Brain Barrier

    PubMed Central

    Zaruba, Kamil; Kunes, Martin; Ulbrich, Pavel; Brezaniova, Ingrid; Triska, Jan; Suchy, Pavel

    2015-01-01

    The blood-brain barrier prevents the passage of many drugs that target the central nervous system. This paper presents the preparation and characterization of silica-based nanocarriers loaded with piracetam, pentoxifylline, and pyridoxine (drugs from the class of nootropics), which are designed to enhance the permeation of the drugs from the circulatory system through the blood-brain barrier. Their permeation was compared with non-nanoparticle drug substances (bulk materials) by means of an in vivo model of rat brain perfusion. The size and morphology of the nanoparticles were characterized by transmission electron microscopy. The content of the drug substances in silica-based nanocarriers was analysed by elemental analysis and UV spectrometry. Microscopic analysis of visualized silica nanocarriers in the perfused brain tissue was performed. The concentration of the drug substances in the tissue was determined by means of UHPLC-DAD/HRMS LTQ Orbitrap XL. It was found that the drug substances in silica-based nanocarriers permeated through the blood brain barrier to the brain tissue, whereas bulk materials were not detected in the brain. PMID:26075264

  4. Blood-brain barrier alteration after microwave-induced hyperthermia is purely a thermal effect: I. Temperature and power measurements

    SciTech Connect

    Moriyama, E.; Salcman, M.; Broadwell, R.D. )

    1991-03-01

    The effect of microwave-induced hyperthermia on the blood-brain barrier was studied in 21 Sprague-Dawley rats. Under sodium pentobarbital anesthesia, animals were place in a stereotactic frame, and an interstitial microwave antenna operating at 2450 MHz was inserted in a bony groove drilled parallel to the sagittal suture. Some antennae were equipped with an external cooling jacket. Temperature measurements were made lateral to the antenna by fluoroptical thermometry, and power was calculated from the time-temperature profile. Five minutes prior to termination of microwave irradiation, horseradish peroxidase (1 mg/20 g body weight) was injected intravenously. Extravasation of horseradish peroxidase was observed in brain tissue heated above 44.3 degrees C for 30 minutes and at 42.5 degrees C for 60 minutes. Microwave irradiation failed to open the blood-brain barrier when brain temperatures were sustained below 40.3 degrees C by the cooling system. Extravasation of blood-borne peroxidase occurred at sites of maximal temperature elevation, even when these did not coincide with the site of maximum power density. The data suggest that microwave-induced hyperthermia is an effective means for opening the blood-brain barrier and that the mechanism is not related to the nonthermal effect of microwaves.

  5. Preparation of silica nanoparticles loaded with nootropics and their in vivo permeation through blood-brain barrier.

    PubMed

    Jampilek, Josef; Zaruba, Kamil; Oravec, Michal; Kunes, Martin; Babula, Petr; Ulbrich, Pavel; Brezaniova, Ingrid; Opatrilova, Radka; Triska, Jan; Suchy, Pavel

    2015-01-01

    The blood-brain barrier prevents the passage of many drugs that target the central nervous system. This paper presents the preparation and characterization of silica-based nanocarriers loaded with piracetam, pentoxifylline, and pyridoxine (drugs from the class of nootropics), which are designed to enhance the permeation of the drugs from the circulatory system through the blood-brain barrier. Their permeation was compared with non-nanoparticle drug substances (bulk materials) by means of an in vivo model of rat brain perfusion. The size and morphology of the nanoparticles were characterized by transmission electron microscopy. The content of the drug substances in silica-based nanocarriers was analysed by elemental analysis and UV spectrometry. Microscopic analysis of visualized silica nanocarriers in the perfused brain tissue was performed. The concentration of the drug substances in the tissue was determined by means of UHPLC-DAD/HRMS LTQ Orbitrap XL. It was found that the drug substances in silica-based nanocarriers permeated through the blood brain barrier to the brain tissue, whereas bulk materials were not detected in the brain. PMID:26075264

  6. Effects of colistin on amino acid neurotransmitters and blood-brain barrier in the mouse brain.

    PubMed

    Wang, Jian; Yi, Meishuang; Chen, Xueping; Muhammad, Ishfaq; Liu, Fangping; Li, Rui; Li, Jian; Li, Jichang

    2016-01-01

    Neurotoxicity is one of the major potential side effects of colistin therapy. However, the mechanistic aspects of colistin-induced neurotoxicity remain largely unknown. The objective of this study was to examine the effects of colistin on the blood-brain barrier (BBB) and amino acid neurotransmitters in the cerebral cortex of mouse. Mice were divided into four groups (n=5) and were administrated intravenously with 15mg/kg/day of colistin sulfate for 1, 3 and 7days successively while the control group was administrated intravenously with saline solution. The permeability and ultrastructure of the BBB were detected using the Evans blue (EB) dye and transmission electron microscopy (TEM), and the expression of Claudin-5 were determined by real-time PCR examination and western blotting. The brain uptake of colistin was measured by high-performance liquid chromatography (HPLC). The effects of colistin on amino acid neurotransmitters and their receptors were also examined by HPLC and real-time PCR. The results of EB extravasation, TEM and expression of Claudin-5 showed that colistin treatment did not affect the BBB integrity. In addition, multiple doses of colistin could induce accumulation of this compound in the brain parenchyma although there was poor brain uptake of colistin. Moreover, colistin exposure significantly increased the contents of glutamate (Glu) and gamma aminobutyric acid (GABA), and enhanced the mRNA expression levels of gamma aminobutyric acid type A receptor (GABAAR), gamma aminobutyric acid type B receptor (GABABR), N-methyl-d-aspartate 1 receptor (NR1), N-methyl-d-aspartate 2A receptor (NR2A) and N-methyl-d-aspartate 2B receptor (NR2B) in the cerebral cortex. Our data demonstrate that colistin is able to accumulate in the mouse brain and elevate the levels of amino acid neurotransmitters. These findings may be associated with colistin-induced neurotoxicity. PMID:27018023

  7. Persistent endothelial abnormalities and blood-brain barrier leak in primary and secondary progressive multiple sclerosis.

    PubMed

    Leech, S; Kirk, J; Plumb, J; McQuaid, S

    2007-02-01

    Epithelial and endothelial tight junctions are pathologically altered in infectious, inflammatory, neoplastic and other diseases. Previously, we described such abnormalities, associated with serum protein leak, in tight junctions of the blood-brain barrier endothelium, in lesional and normal-appearing white matter (NAWM) in secondary progressive (SP) and acute multiple sclerosis (MS). This work is extended here to lesions and NAWM in primary progressive multiple sclerosis (PPMS) and to cortical grey matter in PPMS and SPMS. Immunocytochemistry and semiquantitative confocal microscopy for the tight junction protein zonula occludens 1 (ZO-1) was performed on snap-frozen sections from PPMS (n = 6) and controls (n = 5). Data on 2103 blood vessels were acquired from active lesions (n = 10), inactive lesions (n = 15), NAWM (n = 42) and controls (n = 20). Data on 1218 vessels were acquired from normal-appearing grey matter (PPMS, 5; SPMS, 6; controls, 5). In PPMS abnormal ZO-1 expression in active white matter lesions and NAWM, was found in 42% and 13% of blood vessels, respectively, comparable to previous data from acute and SPMS. In chronic white matter plaques, however, abnormalities were considerably more frequent (37%) in PPMS than in SPMS. Abnormality was also more frequent in normal-appearing grey matter in SPMS (23%) than in PPMS (10%). In summary, abnormal tight junctions in both SPMS and PPMS are most frequent in active white matter lesions but persist in inactive lesions, particularly in PPMS. Abnormal tight junctions are also common in normal-appearing grey matter in SPMS. Persistent endothelial abnormality with leak (PEAL) is therefore widespread but variably expressed in MS and may contribute to disease progression. PMID:17239011

  8. Fingolimod Prevents Blood-Brain Barrier Disruption Induced by the Sera from Patients with Multiple Sclerosis

    PubMed Central

    Nishihara, Hideaki; Shimizu, Fumitaka; Sano, Yasuteru; Takeshita, Yukio; Maeda, Toshihiko; Abe, Masaaki; Koga, Michiaki; Kanda, Takashi

    2015-01-01

    Objective Effect of fingolimod in multiple sclerosis (MS) is thought to involve the prevention of lymphocyte egress from lymphoid tissues, thereby reducing autoaggressive lymphocyte infiltration into the central nervous system across blood-brain barrier (BBB). However, brain microvascular endothelial cells (BMECs) represent a possible additional target for fingolimod in MS patients by directly repairing the function of BBB, as S1P receptors are also expressed by BMECs. In this study, we evaluated the effects of fingolimod on BMECs and clarified whether fingolimod-phosphate restores the BBB function after exposure to MS sera. Methods Changes in tight junction proteins, adhesion molecules and transendothelial electrical resistance (TEER) in BMECs were evaluated following incubation in conditioned medium with or without fingolimod/fingolimod-phosphate. In addition, the effects of sera derived from MS patients, including those in the relapse phase of relapse-remitting (RR) MS, stable phase of RRMS and secondary progressive MS (SPMS), on the function of BBB in the presence of fingolimod-phosphate were assessed. Results Incubation with fingolimod-phosphate increased the claudin-5 protein levels and TEER values in BMECs, although it did not change the amount of occludin, ICAM-1 or MelCAM proteins. Pretreatment with fingolimod-phosphate restored the changes in the claudin-5 and VCAM-1 protein/mRNA levels and TEER values in BMECs after exposure to MS sera. Conclusions Pretreatment with fingolimod-phosphate prevents BBB disruption caused by both RRMS and SPMS sera via the upregulation of claudin-5 and downregulation of VCAM-1 in BMECs, suggesting that fingolimod-phosphate is capable of directly modifying the BBB. BMECs represent a possible therapeutic target for fingolimod in MS patients. PMID:25774903

  9. Blood-brain barrier transport kinetics of the neuromedin peptides NMU, NMN, NMB and NT.

    PubMed

    Gevaert, Bert; Wynendaele, Evelien; Stalmans, Sofie; Bracke, Nathalie; D'Hondt, Matthias; Smolders, Ilse; van Eeckhaut, Ann; De Spiegeleer, Bart

    2016-08-01

    The neuromedin peptides are peripherally and centrally produced, but until now, it is generally believed that they only function as locally acting compounds without any quantitative knowledge about their blood-brain barrier (BBB) passage. Here, we characterize the transport kinetics of four neuromedins (NMU, NMN, NMB and NT) across the BBB, as well as their metabolization profile, and evaluate if they can act as endocrine hormones. Using the in vivo mouse model, multiple time regression (MTR), capillary depletion (CD) and brain efflux studies were performed. Data was fitted using linear (NMU, NT and NMB) or biphasic modeling (NMU and NMN). Three of the four investigated peptides, i.e. NMU, NT and NMN, showed a significant influx into the brain with unidirectional influx rate constants of 1.31 and 0.75 μL/(g × min) for NMU and NT respectively and initial influx constants (K1) of 72.14 and 7.55 μL/(g × min) and net influx constants (K) of 1.28 and 1.36 × 10(-16) μL/(g×min) for NMU and NMN respectively. The influx of NMB was negligible. Only NMN and NT showed a significant efflux out of the brain with an efflux constant (kout) of 0.042 min(-1) and 0.053 min(-1) respectively. Our results indicate that locally produced neuromedin peptides and/or fragments can be transported through the whole body, including passing the BBB, and taken up by different organs/tissues, supporting the idea that the neuromedins could have a much bigger role in the regulation of biological processes than currently assumed. PMID:27040796

  10. Transport of Arylsulfatase A across the Blood-Brain Barrier in Vitro*

    PubMed Central

    Matthes, Frank; Wölte, Philipp; Böckenhoff, Annika; Hüwel, Sabine; Schulz, Mareike; Hyden, Pia; Fogh, Jens; Gieselmann, Volkmar; Galla, Hans-Joachim; Matzner, Ulrich

    2011-01-01

    Enzyme replacement therapy is an option to treat lysosomal storage diseases caused by functional deficiencies of lysosomal hydrolases as intravenous injection of therapeutic enzymes can correct the catabolic defect within many organ systems. However, beneficial effects on central nervous system manifestations are very limited because the blood-brain barrier (BBB) prevents the transfer of enzyme from the circulation to the brain parenchyma. Preclinical studies in mouse models of metachromatic leukodystrophy, however, showed that arylsulfatase A (ASA) is able to cross the BBB to some extent, thus reducing lysosomal storage in brain microglial cells. The present study aims to investigate the routing of ASA across the BBB and to improve the transfer in vitro using a well established cell culture model consisting of primary porcine brain capillary endothelial cells cultured on Transwell filter inserts. Passive apical-to-basolateral ASA transfer was observed, which was not saturable up to high ASA concentrations. No active transport could be determined. The passive transendothelial transfer was, however, charge-dependent as reduced concentrations of negatively charged monosaccharides in the N-glycans of ASA or the addition of polycations increased basolateral ASA levels. Adsorptive transcytosis is therefore considered to be the major transport pathway. Partial inhibition of the transcellular ASA transfer by mannose 6-phosphate indicated a second route depending on the insulin-like growth factor II/mannose 6-phosphate receptor, MPR300. We conclude that cationization of ASA and an increase of the mannose 6-phosphate content of the enzyme may promote blood-to-brain transfer of ASA, thus leading to an improved therapeutic efficacy of enzyme replacement therapy behind the BBB. PMID:21454621

  11. Transport of arylsulfatase A across the blood-brain barrier in vitro.

    PubMed

    Matthes, Frank; Wölte, Philipp; Böckenhoff, Annika; Hüwel, Sabine; Schulz, Mareike; Hyden, Pia; Fogh, Jens; Gieselmann, Volkmar; Galla, Hans-Joachim; Matzner, Ulrich

    2011-05-20

    Enzyme replacement therapy is an option to treat lysosomal storage diseases caused by functional deficiencies of lysosomal hydrolases as intravenous injection of therapeutic enzymes can correct the catabolic defect within many organ systems. However, beneficial effects on central nervous system manifestations are very limited because the blood-brain barrier (BBB) prevents the transfer of enzyme from the circulation to the brain parenchyma. Preclinical studies in mouse models of metachromatic leukodystrophy, however, showed that arylsulfatase A (ASA) is able to cross the BBB to some extent, thus reducing lysosomal storage in brain microglial cells. The present study aims to investigate the routing of ASA across the BBB and to improve the transfer in vitro using a well established cell culture model consisting of primary porcine brain capillary endothelial cells cultured on Transwell filter inserts. Passive apical-to-basolateral ASA transfer was observed, which was not saturable up to high ASA concentrations. No active transport could be determined. The passive transendothelial transfer was, however, charge-dependent as reduced concentrations of negatively charged monosaccharides in the N-glycans of ASA or the addition of polycations increased basolateral ASA levels. Adsorptive transcytosis is therefore considered to be the major transport pathway. Partial inhibition of the transcellular ASA transfer by mannose 6-phosphate indicated a second route depending on the insulin-like growth factor II/mannose 6-phosphate receptor, MPR300. We conclude that cationization of ASA and an increase of the mannose 6-phosphate content of the enzyme may promote blood-to-brain transfer of ASA, thus leading to an improved therapeutic efficacy of enzyme replacement therapy behind the BBB. PMID:21454621

  12. Reengineering biopharmaceuticals for targeted delivery across the blood-brain barrier.

    PubMed

    Pardridge, William M; Boado, Ruben J

    2012-01-01

    Recombinant protein therapeutics cannot enter brain drug development because these large molecule drugs do not cross the blood-brain barrier (BBB). However, recombinant proteins can be reengineered as BBB-penetrating IgG fusion proteins, where the IgG part is a genetically engineered monoclonal antibody (MAb) against an endogenous BBB receptor, such as the human insulin receptor (HIR) or the transferrin receptor (TfR). The IgG binds the endogenous insulin receptor or TfR to trigger transport across the BBB and acts as a molecular Trojan horse (MTH) to ferry into brain the fused protein therapeutic. The most potent MTH to date is a MAb against the HIR, designated the HIRMAb, which is active in humans and Old World primates, such as the Rhesus monkey. There is no known MAb against the mouse insulin receptor. For drug delivery in the mouse, protein therapeutics are fused to a chimeric MAb against the mouse TfR, designated the cTfRMAb. The HIRMAb or cTfRMAb Trojan horses have been engineered and expressed as fusion proteins with multiple classes of protein therapeutics, including lysosomal enzymes, neurotrophins, decoy receptors, single chain Fv therapeutic antibodies, and avidin. The pharmacokinetic (PK) properties of the IgG fusion proteins differ from that of typical MAb drugs and resemble the PK profiles of small molecules due to rapid uptake by peripheral tissues, as well as brain. The brain uptake of the IgG fusion proteins, 2-3% of injected dose/brain, is comparable to the brain uptake of small molecules. The IgG fusion proteins have been administered chronically in mouse models, and the immune response is low titer and has no effect on the fusion protein clearance from blood or brain uptake in vivo. The BBB MTH technology enables the reengineering of a wide spectrum of recombinant protein therapeutics for targeted drug delivery to the brain. PMID:22230573

  13. Iron supplement prevents lead-induced disruption of the blood-brain barrier during rat development

    SciTech Connect

    Wang Qiang; Luo Wenjing; Zheng Wei; Liu Yiping; Xu Hui; Zheng Gang; Dai Zhongming; Zhang Wenbin; Chen Yaoming; Chen Jingyuan . E-mail: jy_chen@fmmu.edu.cn

    2007-02-15

    Children are known to be venerable to lead (Pb) toxicity. The blood-brain barrier (BBB) in immature brain is particularly vulnerable to Pb insults. This study was designed to test the hypothesis that Pb exposure damaged the integrity of the BBB in young animals and iron (Fe) supplement may prevent against Pb-induced BBB disruption. Male weanling Sprague-Dawley rats were divided into four groups. Three groups of rats were exposed to Pb in drinking water containing 342 {mu}g Pb/mL as Pb acetate, among which two groups were concurrently administered by oral gavage once every other day with 7 mg Fe/kg and 14 mg Fe/kg as FeSO{sub 4} solution as the low and high Fe treatment group, respectively, for 6 weeks. The control group received sodium acetate in drinking water. Pb exposure significantly increased Pb concentrations in blood by 6.6-folds (p < 0.05) and brain tissues by 1.5-2.0-folds (p < 0.05) as compared to controls. Under the electron microscope, Pb exposure in young animals caused an extensive extravascular staining of lanthanum nitrate in brain parenchyma, suggesting a leakage of cerebral vasculature. Western blot showed that Pb treatment led to 29-68% reduction (p < 0.05) in the expression of occludin as compared to the controls. Fe supplement among Pb-exposed rats maintained the normal ultra-structure of the BBB and restored the expression of occludin to normal levels. Moreover, the low dose Fe supplement significantly reduced Pb levels in blood and brain tissues. These data suggest that Pb exposure disrupts the structure of the BBB in young animals. The increased BBB permeability may facilitate the accumulation of Pb. Fe supplement appears to protect the integrity of the BBB against Pb insults, a beneficial effect that may have significant clinical implications.

  14. A novel platform for engineering blood-brain barrier-crossing bispecific biologics.

    PubMed

    Farrington, Graham K; Caram-Salas, Nadia; Haqqani, Arsalan S; Brunette, Eric; Eldredge, John; Pepinsky, Blake; Antognetti, Giovanna; Baumann, Ewa; Ding, Wen; Garber, Ellen; Jiang, Susan; Delaney, Christie; Boileau, Eve; Sisk, William P; Stanimirovic, Danica B

    2014-11-01

    The blood-brain barrier (BBB) prevents the access of therapeutic antibodies to central nervous system (CNS) targets. The engineering of bispecific antibodies in which a therapeutic "arm" is combined with a BBB-transcytosing arm can significantly enhance their brain delivery. The BBB-permeable single-domain antibody FC5 was previously isolated by phenotypic panning of a naive llama single-domain antibody phage display library. In this study, FC5 was engineered as a mono- and bivalent fusion with the human Fc domain to optimize it as a modular brain delivery platform. In vitro studies demonstrated that the bivalent fusion of FC5 with Fc increased the rate of transcytosis (Papp) across brain endothelial monolayer by 25% compared with monovalent fusion. Up to a 30-fold enhanced apparent brain exposure (derived from serum and cerebrospinal fluid pharmacokinetic profiles) of FC5- compared with control domain antibody-Fc fusions after systemic dosing in rats was observed. Systemic pharmacological potency was evaluated in the Hargreaves model of inflammatory pain using the BBB-impermeable neuropeptides dalargin and neuropeptide Y chemically conjugated with FC5-Fc fusion proteins. Improved serum pharmacokinetics of Fc-fused FC5 contributed to a 60-fold increase in pharmacological potency compared with the single-domain version of FC5; bivalent and monovalent FC5 fusions with Fc exhibited similar systemic pharmacological potency. The study demonstrates that modular incorporation of FC5 as the BBB-carrier arm in bispecific antibodies or antibody-drug conjugates offers an avenue to develop pharmacologically active biotherapeutics for CNS indications. PMID:25070367

  15. Endothelial LRP1 transports amyloid-β1–42 across the blood-brain barrier

    PubMed Central

    Storck, Steffen E.; Meister, Sabrina; Nahrath, Julius; Meißner, Julius N.; Schubert, Nils; Di Spiezio, Alessandro; Baches, Sandra; Vandenbroucke, Roosmarijn E.; Bouter, Yvonne; Prikulis, Ingrid; Korth, Carsten; Weggen, Sascha; Heimann, Axel; Schwaninger, Markus; Bayer, Thomas A.; Pietrzik, Claus U.

    2015-01-01

    According to the neurovascular hypothesis, impairment of low-density lipoprotein receptor–related protein-1 (LRP1) in brain capillaries of the blood-brain barrier (BBB) contributes to neurotoxic amyloid-β (Aβ) brain accumulation and drives Alzheimer’s disease (AD) pathology. However, due to conflicting reports on the involvement of LRP1 in Aβ transport and the expression of LRP1 in brain endothelium, the role of LRP1 at the BBB is uncertain. As global Lrp1 deletion in mice is lethal, appropriate models to study the function of LRP1 are lacking. Moreover, the relevance of systemic Aβ clearance to AD pathology remains unclear, as no BBB-specific knockout models have been available. Here, we developed transgenic mouse strains that allow for tamoxifen-inducible deletion of Lrp1 specifically within brain endothelial cells (Slco1c1-CreERT2 Lrp1fl/fl mice) and used these mice to accurately evaluate LRP1-mediated Aβ BBB clearance in vivo. Selective deletion of Lrp1 in the brain endothelium of C57BL/6 mice strongly reduced brain efflux of injected [125I] Aβ1–42. Additionally, in the 5xFAD mouse model of AD, brain endothelial–specific Lrp1 deletion reduced plasma Aβ levels and elevated soluble brain Aβ, leading to aggravated spatial learning and memory deficits, thus emphasizing the importance of systemic Aβ elimination via the BBB. Together, our results suggest that receptor-mediated Aβ BBB clearance may be a potential target for treatment and prevention of Aβ brain accumulation in AD. PMID:26619118

  16. Mosquito repellent (pyrethroid-based) induced dysfunction of blood-brain barrier permeability in developing brain.

    PubMed

    Sinha, C; Agrawal, A K; Islam, F; Seth, K; Chaturvedi, R K; Shukla, S; Seth, P K

    2004-02-01

    Pyrethroid-based mosquito repellents (MR) are commonly used to protect humans against mosquito vector. New born babies and children are often exposed to pyrethroids for long periods by the use of liquid vaporizers. Occupational and experimental studies indicate that pyrethroids can cause clinical, biochemical and neurological changes, and that exposure to pyrethroids during organogenesis and early developmental period is especially harmful. The neurotoxicity caused by MR has aroused concern among public regarding their use. In the present study, the effect of exposure of rat pups during early developmental stages to a pyrethroid-based MR (allethrin, 3.6% w/v, 8h per day through inhalation) on blood-brain barrier (BBB) permeability was investigated. Sodium fluororescein (SF) and Evan's blue (EB) were used as micromolecular and macromolecular tracers, respectively. Exposure during prenatal (gestation days 1-20), postnatal (PND1-30) and perinatal (gestation days 1-20 + PND1-30) periods showed significant increase in the brain uptake index (BUI) of SF by 54% (P < 0.01), 70% (P < 0.01), 79% (P < 0.01), respectively. This increase persisted (68%, P < 0.01) even 1 week after withdrawal of exposure (as assessed on PND37). EB did not exhibit significant change in BBB permeability in any of the group. The results suggest that MR inhalation during early prenatal/postnatal/perinatal life may have adverse effects on infants leading to central nervous system (CNS) abnormalities, if a mechanism operates in humans similar to that in rat pups. PMID:15013076

  17. Peripheral ammonia and blood brain barrier structure and function after methamphetamine.

    PubMed

    Northrop, Nicole A; Halpin, Laura E; Yamamoto, Bryan K

    2016-08-01

    An effect of the widely abuse psychostimulant, methamphetamine (Meth), is blood-brain-barrier (BBB) disruption; however, the mechanism by which Meth causes BBB disruption remains unclear. Recently it has been shown that Meth produces liver damage and consequent increases in plasma ammonia. Ammonia can mediate oxidative stress and inflammation, both of which are known to cause BBB disruption. Therefore, the current studies examined the role of peripheral ammonia in Meth-induced disruption of BBB structure and function. A neurotoxic Meth regimen (10 mg/kg, ip, q 2 h, ×4) administered to rats increased plasma ammonia and active MMP-9 in the cortex 2 h after the last Meth injection, compared to saline treated rats. At 24 h after Meth treatment, decreased immunoreactivity of BBB structural proteins, occludin and claudin-5, and increased extravasation of 10,000 Da FITC-dextran were observed, as compared to saline controls. Pretreatment with lactulose (5.3 g/kg, po, q 12 h), a drug that remains in the lumen of the intestine and promotes ammonia excretion, prevented the Meth-induced increases in plasma ammonia. These results were paralleled by the prevention of decreases in BBB structural proteins, increases in extravasation of 10,000 Da FITC-dextran and increases in active MMP-9. The results indicate that Meth-induced increases in ammonia produce BBB disruption and suggest that MMP-9 activation mediates the BBB disruption. These findings identify a novel mechanism of Meth-induced BBB disruption that is mediated by plasma ammonia and are the first to identify a peripheral contribution to Meth-induced BBB disruption. PMID:26972828

  18. Methamphetamine is not Toxic but Disrupts the Cell Cycle of Blood-Brain Barrier Endothelial Cells.

    PubMed

    Fisher, D; Gamieldien, K; Mafunda, P S

    2015-07-01

    The cytotoxic effects of methamphetamine (MA) are well established to be caused via induced oxidative stress which in turn compromises the core function of the blood-brain barrier (BBB) by reducing its ability to regulate the homeostatic environment of the brain. While most studies were conducted over a period of 24-48 h, this study investigated the mechanisms by which chronic exposure of MA adversely affect the endothelial cells of BBB over an extended period of 96 h. MA induced significant depression of cell numbers at 96 h. This result was supported by flow cytometric data on the cell cycle which showed that brain endothelial cells (bEnd5) at 96 h were significantly suppressed in the S-phase of the cell cycle. In contrast, at 24-72 h control cell numbers for G1, S and G2-M phases were similar to MA-exposed cells. MA (0-1,000 µM) did not, however, statistically affect the viability and cytotoxicity of the bEnd5 cells, and the profile of ATP production and DNA synthesis (BrdU) across 96 h did not provide a rationale for the suppression of cell division. Our study reports for the first time that chronic exposure to MA results in long-term disruption of the cell cycle phases which eventuates in the attenuation of brain capillary endothelial cell growth after 96 h, compounding and contributing to the already well-known adverse short-term permeability effects of MA exposure on the BBB. PMID:25666340

  19. Effects of radiofrequency radiation exposure on blood-brain barrier permeability in male and female rats.

    PubMed

    Sirav, Bahriye; Seyhan, Nesrin

    2011-12-01

    During the last several decades, numerous studies have been performed aiming at the question of whether or not exposure to radiofrequency radiation (RFR) influences the permeability of the blood-brain barrier (BBB). The objective of this study was to investigate the effect of RFR on the permeability of BBB in male and female Wistar albino rats. Right brain, left brain, cerebellum, and total brain were analyzed separately in the study. Rats were exposed to 0.9 and 1.8 GHz continuous-wave (CW) RFR for 20 min (at SARs of 4.26 mW/kg and 1.46 mW/kg, respectively) while under anesthesia. Control rats were sham-exposed. Disruption of BBB integrity was detected spectrophotometrically using the Evans-blue dye, which has been used as a BBB tracer and is known to be bound to serum albumin. Right brain, left brain, cerebellum, and total brain were evaluated for BBB permeability. In female rats, no albumin extravasation was found in in the brain after RFR exposure. A significant increase in albumin was found in the brains of the RF-exposed male rats when compared to sham-exposed male brains. These results suggest that exposure to 0.9 and 1.8 GHz CW RFR at levels below the international limits can affect the vascular permeability in the brain of male rats. The possible risk of RFR exposure in humans is a major concern for the society. Thus, this topic should be investigated more thoroughly in the future. PMID:22047463

  20. The Role of Autophagy during Group B Streptococcus Infection of Blood-Brain Barrier Endothelium*

    PubMed Central

    Cutting, Andrew S.; Del Rosario, Yvette; Mu, Rong; Rodriguez, Anthony; Till, Andreas; Subramani, Suresh; Gottlieb, Roberta A.; Doran, Kelly S.

    2014-01-01

    Bacterial meningitis occurs when bloodborne pathogens invade and penetrate the blood-brain barrier (BBB), provoking inflammation and disease. Group B Streptococcus (GBS), the leading cause of neonatal meningitis, can enter human brain microvascular endothelial cells (hBMECs), but the host response to intracellular GBS has not been characterized. Here we sought to determine whether antibacterial autophagy, which involves selective recognition of intracellular organisms and their targeting to autophagosomes for degradation, is activated in BBB endothelium during bacterial infection. GBS infection resulted in increased punctate distribution of GFP-microtubule-associated protein 1 light chain 3 (LC3) and increased levels of endogenous LC3-II and p62 turnover, two hallmark indicators of active autophagic flux. Infection with GBS mutants revealed that bacterial invasion and the GBS pore-forming β-hemolysin/cytolysin (β-h/c) trigger autophagic activation. Cell-free bacterial extracts containing β-h/c activity induced LC3-II conversion, identifying this toxin as a principal provocative factor for autophagy activation. These results were confirmed in vivo using a mouse model of GBS meningitis as infection with WT GBS induced autophagy in brain tissue more frequently than a β-h/c-deficient mutant. Elimination of autophagy using Atg5-deficient fibroblasts or siRNA-mediated impairment of autophagy in hBMECs led to increased recovery of intracellular GBS. However, electron microscopy revealed that GBS was rarely found within double membrane autophagic structures even though we observed GBS-LC3 co-localization. These results suggest that although autophagy may act as a BBB cellular defense mechanism in response to invading and toxin-producing bacteria, GBS may actively thwart the autophagic pathway. PMID:25371213

  1. Bryostatin-1 Restores Blood Brain Barrier Integrity following Blast-Induced Traumatic Brain Injury.

    PubMed

    Lucke-Wold, Brandon P; Logsdon, Aric F; Smith, Kelly E; Turner, Ryan C; Alkon, Daniel L; Tan, Zhenjun; Naser, Zachary J; Knotts, Chelsea M; Huber, Jason D; Rosen, Charles L

    2015-12-01

    Recent wars in Iraq and Afghanistan have accounted for an estimated 270,000 blast exposures among military personnel. Blast traumatic brain injury (TBI) is the 'signature injury' of modern warfare. Blood brain barrier (BBB) disruption following blast TBI can lead to long-term and diffuse neuroinflammation. In this study, we investigate for the first time the role of bryostatin-1, a specific protein kinase C (PKC) modulator, in ameliorating BBB breakdown. Thirty seven Sprague-Dawley rats were used for this study. We utilized a clinically relevant and validated blast model to expose animals to moderate blast exposure. Groups included: control, single blast exposure, and single blast exposure + bryostatin-1. Bryostatin-1 was administered i.p. 2.5 mg/kg after blast exposure. Evan's blue, immunohistochemistry, and western blot analysis were performed to assess injury. Evan's blue binds to albumin and is a marker for BBB disruption. The single blast exposure caused an increase in permeability compared to control (t = 4.808, p < 0.05), and a reduction back toward control levels when bryostatin-1 was administered (t = 5.113, p < 0.01). Three important PKC isozymes, PKCα, PKCδ, and PKCε, were co-localized primarily with endothelial cells but not astrocytes. Bryostatin-1 administration reduced toxic PKCα levels back toward control levels (t = 4.559, p < 0.01) and increased the neuroprotective isozyme PKCε (t = 6.102, p < 0.01). Bryostatin-1 caused a significant increase in the tight junction proteins VE-cadherin, ZO-1, and occludin through modulation of PKC activity. Bryostatin-1 ultimately decreased BBB breakdown potentially due to modulation of PKC isozymes. Future work will examine the role of bryostatin-1 in preventing chronic neurodegeneration following repetitive neurotrauma. PMID:25301233

  2. Long-Term Blood-Brain Barrier Permeability Changes in Binswanger’s Disease

    PubMed Central

    Huisa, Branko N; Caprihan, Arvind; Thompson, Jeffrey; Prestopnik, Jillian; Qualls, Clifford R; Rosenberg, Gary A

    2015-01-01

    Background and Purpose The blood brain-barrier (BBB) is disrupted in small vessel disease (SVD) patients with lacunes and white matter hyperintensities (WMHs). The relationship of WMHs and regional BBB permeability changes has not been studied. We hypothesized that BBB disruption occurs in normal appearing WM (NAWM) and regions near the WMHs. To test the hypothesis, we repeated BBB permeability measurements in patients with extensive WMHs related to Binswanger’s disease (BD). Methods We selected a subset of 22 BD subjects from a well-characterized larger prospective vascular cognitive impairment cohort. We used 16 age-matched controls for comparison. The abnormal WM permeability (WMP) was measured twice over several years using dynamic contrast-enhanced MRI (DCEMRI). WMP maps were constructed from voxels above a predetermined threshold. Scans from first and second visits were co-registered. WM was divided into 3 regions: NAWM, WMH ring and WMH core. The ring was defined as 2mm on each side of the WMH border. WMP was calculated in each of the three specific regions. We used paired t-test, ANOVA and Fisher’s exact test to compare individual changes. Results WMP was significantly higher in subjects than controls (p<0.001). There was no correlation between WMH load and WMP. High permeability regions had minimal overlap between first and second scans. Nine percent of WMP was within the WMHs, 49% within the NAWM, and 52% within the WMH ring (p<0.001; ANOVA). Conclusions Increased BBB permeability in NAWM and close to the WMH borders supports a relationship between BBB disruption and development of WMHs. PMID:26205374

  3. Plasma protein binding limits the blood brain barrier permeation of the pyrethroid insecticide, deltamethrin.

    PubMed

    Amaraneni, Manoj; Sharma, Anshika; Pang, Jing; Muralidhara, Srinivasa; Cummings, Brian S; White, Catherine A; Bruckner, James V; Zastre, Jason

    2016-05-27

    Previous pharmacokinetic studies of deltamethrin (DLM) have revealed that brain levels of this highly lipophilic pyrethroid insecticide are only 15-20% of plasma levels. Experiments were performed to assess determinants limiting CNS access including plasma protein binding and the efflux transporter, P-gp. A human brain microvascular endothelial cell line, hCMEC/D3, was utilized as a model in vitro system to evaluate blood-brain barrier (BBB) permeation. Incubation of DLM with a series of human serum albumin (HSA) concentrations showed that unbound (fu) DLM ranged from 80% with 0.01% HSA to ∼20% at the physiologically-relevant 4% HSA. A positive correlation (R=0.987) was seen between fu and cellular uptake. Concentration-dependent uptake of DLM in 0.01% HSA was non-linear and was reduced at 4°C and by the P-gp inhibitor cyclosporine (CSA), indicative of a specific transport process. Cellular accumulation of [(3)H]-paclitaxel, a P-glycoprotein (P-gp) substrate, was increased by CSA but not by DLM, suggesting that DLM is neither a substrate nor an inhibitor of P-gp. The concentration-dependent uptake of DLM from 4% HSA was linear and not significantly impacted by temperature or CSA. In situ brain perfusion studies monitoring brain association of DLM at 0.01% and 4% HSA confirmed the aforementioned in vitro findings. This study demonstrates that brain uptake of DLM under normal physiological conditions appears to be a passive, non-saturable process, limited by the high protein binding of the pyrethroid. PMID:27016408

  4. In vitro blood-brain barrier permeability predictions for GABAA receptor modulating piperine analogs.

    PubMed

    Eigenmann, Daniela Elisabeth; Dürig, Carmen; Jähne, Evelyn Andrea; Smieško, Martin; Culot, Maxime; Gosselet, Fabien; Cecchelli, Romeo; Helms, Hans Christian Cederberg; Brodin, Birger; Wimmer, Laurin; Mihovilovic, Marko D; Hamburger, Matthias; Oufir, Mouhssin

    2016-06-01

    The alkaloid piperine from black pepper (Piper nigrum L.) and several synthetic piperine analogs were recently identified as positive allosteric modulators of γ-aminobutyric acid type A (GABAA) receptors. In order to reach their target sites of action, these compounds need to enter the brain by crossing the blood-brain barrier (BBB). We here evaluated piperine and five selected analogs (SCT-66, SCT-64, SCT-29, LAU397, and LAU399) regarding their BBB permeability. Data were obtained in three in vitro BBB models, namely a recently established human model with immortalized hBMEC cells, a human brain-like endothelial cells (BLEC) model, and a primary animal (bovine endothelial/rat astrocytes co-culture) model. For each compound, quantitative UHPLC-MS/MS methods in the range of 5.00-500ng/mL in the corresponding matrix were developed, and permeability coefficients in the three BBB models were determined. In vitro predictions from the two human BBB models were in good agreement, while permeability data from the animal model differed to some extent, possibly due to protein binding of the screened compounds. In all three BBB models, piperine and SCT-64 displayed the highest BBB permeation potential. This was corroborated by data from in silico prediction. For the other piperine analogs (SCT-66, SCT-29, LAU397, and LAU399), BBB permeability was low to moderate in the two human BBB models, and moderate to high in the animal BBB model. Efflux ratios (ER) calculated from bidirectional permeability experiments indicated that the compounds were likely not substrates of active efflux transporters. PMID:27018328

  5. Use of Ultrasound Pulses Combined with Definity for Targeted Blood-Brain Barrier Disruption

    NASA Astrophysics Data System (ADS)

    McDannold, Nathan; Vykhodtseva, Natalia; Hynynen, Kullervo

    2007-05-01

    We have developed a method to combine an ultrasound contrast agent (USCA) with low-intensity focused ultrasound pulses combined to produce temporary blood-brain barrier disruption (BBBD), a potential non-invasive means for targeted drug delivery in the brain. All of our previous work used the USCA Optison. The purpose of this work was to test the feasibility of using the USCA Definity for BBBD. Thirty-six non-overlapping locations were sonicated through a craniotomy in experiments in the brains of nine rabbits (4 locations per rabbit; US frequency: 0.69MHz, burst: 10ms, PRF: 1Hz, duration: 20s; pressure amplitude: 0.2-1.5 MPa). Eleven locations were sonicated using Optison at 0.5 MPa. For both agents, the probability for BBBD was estimated to be 50% at 0.4 MPa using probit regression. In histology, small isolated areas of extravasated erythrocytes were observed in some locations. At 0.8 MPa and above, this extravasation was sometimes accompanied by tiny (dimensions of 100 μm or less) regions of damaged brain parenchyma. The magnitude of the BBBD was larger with Optison than with Definity at 0.5 MPa (P=0.04), and more areas with extravasated erythrocytes were observed (P=0.03). We conclude that BBBD is possible using Definity for the dosage of USCA and the acoustic parameters tested in this study. While the probability for BBBD as a function of pressure amplitude and the type of acute tissue effects was similar to findings with Optison, under these experimental conditions, Optison produced a larger effect.

  6. Separation methods that are capable of revealing blood-brain barrier permeability.

    PubMed

    Dash, Alekha K; Elmquist, William F

    2003-11-25

    The objective of this review is to emphasize the application of separation science in evaluating the blood-brain barrier (BBB) permeability to drugs and bioactive agents. Several techniques have been utilized to quantitate the BBB permeability. These methods can be classified into two major categories: in vitro or in vivo. The in vivo methods used include brain homogenization, cerebrospinal fluid (CSF) sampling, voltametry, autoradiography, nuclear magnetic resonance (NMR) spectroscopy, positron emission tomography (PET), intracerebral microdialysis, and brain uptake index (BUI) determination. The in vitro methods include tissue culture and immobilized artificial membrane (IAM) technology. Separation methods have always played an important role as adjunct methods to the methods outlined above for the quantitation of BBB permeability and have been utilized the most with brain homogenization, in situ brain perfusion, CSF sampling, intracerebral microdialysis, in vitro tissue culture and IAM chromatography. However, the literature published to date indicates that the separation method has been used the most in conjunction with intracerebral microdialysis and CSF sampling methods. The major advantages of microdialysis sampling in BBB permeability studies is the possibility of online separation and quantitation as well as the need for only a small sample volume for such an analysis. Separation methods are preferred over non-separation methods in BBB permeability evaluation for two main reasons. First, when the selectivity of a determination method is insufficient, interfering substances must be separated from the analyte of interest prior to determination. Secondly, when large number of analytes is to be detected and quantitated by a single analytical procedure, the mixture must be separated to each individual component prior to determination. Chiral separation in particular can be essential to evaluate the stereo-selective permeation and distribution of agents into the

  7. Longitudinal Motor and Behavioral Assessment of Blood-Brain Barrier Opening with Transcranial Focused Ultrasound.

    PubMed

    Olumolade, Oluyemi O; Wang, Shutao; Samiotaki, Gesthimani; Konofagou, Elisa E

    2016-09-01

    Focused ultrasound (FUS), in combination with microbubbles, has been found to open the blood-brain barrier (BBB) non-invasively. When this technique is used for drug delivery, repeated drug administration and BBB opening are likely required. Therefore, it is worth investigating the long-term effects of FUS-induced BBB opening. In this study, we focused on the assessment of potential behavior changes in mice that could be attributed to repeated BBB opening for up to 6 months. The striatum of animals was unilaterally sonicated either monthly or biweekly throughout the monitoring period. Behavioral assessments were conducted using open-field and rotarod performance tests. Upon completion of each sonication, mice underwent magnetic resonance imaging (MRI) to confirm and assess the volume of the BBB opening. No differences in locomotor activity between BBB-opened and control groups in both biweekly and monthly treated mice were evident up to 6 months. Similarly, there was no affinity for a particular turn angle in the sonicated mice compared with the control animals. However, the positive control group exhibited a significant decrease in locomotor activity, as well as rotation ipsilateral to the sonicated hemisphere. Our results based on the assessment using open-field and rotarod tests indicated that repeated opening of the BBB in the striatum using FUS in conjunction with microbubbles over a period of 6 mo and under the parameters used here did not cause motor impairment, behavioral changes or morphologic alterations. This reinforces the tolerability of repeated and long-term drug delivery using FUS-induced BBB opening. PMID:27339763

  8. Nanoparticle-based evaluation of blood brain-barrier leakage during the foreign body response

    PubMed Central

    Sawyer, Andrew J.; Kyriakides, Themis R.

    2013-01-01

    Objective The brain foreign body response (FBR) is an important process that limits the functionality of electrodes that comprise the brain-machine interface. Associated events in this process include leakage of the blood brain barrier (BBB), reactive astrogliosis, recruitment and activation of microglia, and neuronal degeneration. Proper BBB function is also integral to maintaining neuronal health and function. Previous attempts to characterize BBB integrity have shown homogeneous leakage of macromolecules up to 10 nm in size. In the present study, we describe a new method of measuring BBB permeability during the foreign body response in a mouse model. Approach Fluorescent nanoparticles were delivered via the tail vein into implant-bearing mice. Tissue sections were then analyzed using fluorescence microscopy to observe nanoparticles in the tissue. Gold nanoparticles were also used in conjunction with TEM to confirm the presence of nanoparticles in the brain parenchyma. Main results By using polymer nanoparticle tracers, which are significantly larger than conventional macromolecular tracers, we show near-implant BBB gaps of up to 500 nm in size that persist for at least 4 weeks after implantation. Further characterization of the BBB illustrates that leakage during the brain FBR is heterogeneous with gaps between at least 10 and 500 nm. Moreover, electron microscopy was used to confirm that the nanoparticle tracers enter into the brain parenchyma near chronic brain implants. Significance Taken together, our findings demonstrate that the FBR-induced BBB leakage is characterized by larger gaps and is of longer duration than previously thought. This technique can be applied to examine the BBB in other disease states as well as during induced, transient, BBB opening. PMID:23337399

  9. Consequences of Repeated Blood-Brain Barrier Disruption in Football Players

    PubMed Central

    Puvenna, Vikram; Janigro, Mattia; Ghosh, Chaitali; Zhong, Jianhui; Zhu, Tong; Blackman, Eric; Stewart, Desiree; Ellis, Jasmina; Butler, Robert; Janigro, Damir

    2013-01-01

    The acknowledgement of risks for traumatic brain injury in American football players has prompted studies for sideline concussion diagnosis and testing for neurological deficits. While concussions are recognized etiological factors for a spectrum of neurological sequelae, the consequences of sub-concussive events are unclear. We tested the hypothesis that blood-brain barrier disruption (BBBD) and the accompanying surge of the astrocytic protein S100B in blood may cause an immune response associated with production of auto-antibodies. We also wished to determine whether these events result in disrupted white matter on diffusion tensor imaging (DT) scans. Players from three college football teams were enrolled (total of 67 volunteers). None of the players experienced a concussion. Blood samples were collected before and after games (n = 57); the number of head hits in all players was monitored by movie review and post-game interviews. S100B serum levels and auto-antibodies against S100B were measured and correlated by direct and reverse immunoassays (n = 15 players; 5 games). A subset of players underwent DTI scans pre- and post-season and after a 6-month interval (n = 10). Cognitive and functional assessments were also performed. After a game, transient BBB damage measured by serum S100B was detected only in players experiencing the greatest number of sub-concussive head hits. Elevated levels of auto-antibodies against S100B were elevated only after repeated sub-concussive events characterized by BBBD. Serum levels of S100B auto-antibodies also predicted persistence of MRI-DTI abnormalities which in turn correlated with cognitive changes. Even in the absence of concussion, football players may experience repeated BBBD and serum surges of the potential auto-antigen S100B. The correlation of serum S100B, auto-antibodies and DTI changes support a link between repeated BBBD and future risk for cognitive changes. PMID:23483891

  10. Into rather unexplored terrain-transcellular transport across the blood-brain barrier.

    PubMed

    De Bock, Marijke; Van Haver, Valérie; Vandenbroucke, Roosmarijn E; Decrock, Elke; Wang, Nan; Leybaert, Luc

    2016-07-01

    Efficient neuronal signaling in the central nervous system strictly depends on a well-balanced microenvironment around glial cells, synapses, and axons. Unique features of the blood-brain barrier (BBB) endothelium largely determine the composition of this micro-milieu and are dependent on the tight interplay with surrounding astrocytes and pericytes. BBB endothelial cells are endowed with a highly restrictive junctional complex that occludes the intercellular cleft, thereby preventing paracellular diffusion. The paracellular pathway is subject to extensive research as integrity loss of the junctional complex is associated with many neuropathologies, inflammation, and edema. Another important feature of the BBB endothelium is the low prevalence of nonspecific, transcytotic events, including (macro)pinocytosis, clathrin-dependent and caveolin-dependent endocytosis and the subsequent trafficking of vesicles to the opposite membrane. Although less studied, evidence is accruing that this pathway importantly contributes to increased BBB permeability, often when the junctional complex remains intact. Here, we review current knowledge on the contribution of the transcellular pathway to the BBB leak observed in different pathologic conditions. In addition, we hypothesize that nonselective, large pore connexin and pannexin channels may contribute to transcellular transport, either by providing a direct diffusion pathway across the endothelial monolayer, or indirectly, by exerting control over intracellular levels of the signaling ion Ca(2+) that is involved in many steps of the vesicular pathway. We conclude that transcytotic events at the BBB, despite being less acknowledged, cannot be simply dismissed as done in the past, but actively contribute to BBB leakage in many different pathologies. GLIA 2016;64:1097-1123. PMID:26852907

  11. Chirp- and random-based coded ultrasonic excitation for localized blood-brain barrier opening.

    PubMed

    Kamimura, H A S; Wang, S; Wu, S-Y; Karakatsani, M E; Acosta, C; Carneiro, A A O; Konofagou, E E

    2015-10-01

    Chirp- and random-based coded excitation methods have been proposed to reduce standing wave formation and improve focusing of transcranial ultrasound. However, no clear evidence has been shown to support the benefits of these ultrasonic excitation sequences in vivo. This study evaluates the chirp and periodic selection of random frequency (PSRF) coded-excitation methods for opening the blood-brain barrier (BBB) in mice. Three groups of mice (n  =  15) were injected with polydisperse microbubbles and sonicated in the caudate putamen using the chirp/PSRF coded (bandwidth: 1.5–1.9 MHz, peak negative pressure: 0.52 MPa, duration: 30 s) or standard ultrasound (frequency: 1.5 MHz, pressure: 0.52 MPa, burst duration: 20 ms, duration: 5 min) sequences. T1-weighted contrast-enhanced MRI scans were performed to quantitatively analyze focused ultrasound induced BBB opening. The mean opening volumes evaluated from the MRI were mm3, mm3and mm3 for the chirp, random and regular sonications, respectively. The mean cavitation levels were V.s, V.s and V.s for the chirp, random and regular sonications, respectively. The chirp and PSRF coded pulsing sequences improved the BBB opening localization by inducing lower cavitation levels and smaller opening volumes compared to results of the regular sonication technique. Larger bandwidths were associated with more focused targeting but were limited by the frequency response of the transducer, the skull attenuation and the microbubbles optimal frequency range. The coded methods could therefore facilitate highly localized drug delivery as well as benefit other transcranial ultrasound techniques that use higher pressure levels and higher precision to induce the necessary bioeffects in a brain region while avoiding damage to the surrounding healthy tissue. PMID:26394091

  12. Effects of a disrupted blood-brain barrier on cholesterol homeostasis in the brain.

    PubMed

    Saeed, Ahmed A; Genové, Guillem; Li, Tian; Lütjohann, Dieter; Olin, Maria; Mast, Natalia; Pikuleva, Irina A; Crick, Peter; Wang, Yuqin; Griffiths, William; Betsholtz, Christer; Björkhem, Ingemar

    2014-08-22

    The presence of the blood-brain barrier (BBB) is critical for cholesterol metabolism in the brain, preventing uptake of lipoprotein-bound cholesterol from the circulation. The metabolic consequences of a leaking BBB for cholesterol metabolism have not been studied previously. Here we used a pericyte-deficient mouse model, Pdgfb(ret/ret), shown to have increased permeability of the BBB to a range of low-molecular mass and high-molecular mass tracers. There was a significant accumulation of plant sterols in the brains of the Pdgfb(ret/ret) mice. By dietary treatment with 0.3% deuterium-labeled cholesterol, we could demonstrate a significant flux of cholesterol from the circulation into the brains of the mutant mice roughly corresponding to about half of the measured turnover of cholesterol in the brain. We expected the cholesterol flux into the brain to cause a down-regulation of cholesterol synthesis. Instead, cholesterol synthesis was increased by about 60%. The levels of 24(S)-hydroxycholesterol (24S-OHC) were significantly reduced in the brains of the pericyte-deficient mice but increased in the circulation. After treatment with 1% cholesterol in diet, the difference in cholesterol synthesis between mutants and controls disappeared. The findings are consistent with increased leakage of 24S-OHC from the brain into the circulation in the pericyte-deficient mice. This oxysterol is an efficient suppressor of cholesterol synthesis, and the results are consistent with a regulatory role of 24S-OHC in the brain. To our knowledge, this is the first demonstration that a defective BBB may lead to increased flux of a lipophilic compound out from the brain. The relevance of the findings for the human situation is discussed. PMID:24973215

  13. Consequences of repeated blood-brain barrier disruption in football players.

    PubMed

    Marchi, Nicola; Bazarian, Jeffrey J; Puvenna, Vikram; Janigro, Mattia; Ghosh, Chaitali; Zhong, Jianhui; Zhu, Tong; Blackman, Eric; Stewart, Desiree; Ellis, Jasmina; Butler, Robert; Janigro, Damir

    2013-01-01

    The acknowledgement of risks for traumatic brain injury in American football players has prompted studies for sideline concussion diagnosis and testing for neurological deficits. While concussions are recognized etiological factors for a spectrum of neurological sequelae, the consequences of sub-concussive events are unclear. We tested the hypothesis that blood-brain barrier disruption (BBBD) and the accompanying surge of the astrocytic protein S100B in blood may cause an immune response associated with production of auto-antibodies. We also wished to determine whether these events result in disrupted white matter on diffusion tensor imaging (DT) scans. Players from three college football teams were enrolled (total of 67 volunteers). None of the players experienced a concussion. Blood samples were collected before and after games (n = 57); the number of head hits in all players was monitored by movie review and post-game interviews. S100B serum levels and auto-antibodies against S100B were measured and correlated by direct and reverse immunoassays (n = 15 players; 5 games). A subset of players underwent DTI scans pre- and post-season and after a 6-month interval (n = 10). Cognitive and functional assessments were also performed. After a game, transient BBB damage measured by serum S100B was detected only in players experiencing the greatest number of sub-concussive head hits. Elevated levels of auto-antibodies against S100B were elevated only after repeated sub-concussive events characterized by BBBD. Serum levels of S100B auto-antibodies also predicted persistence of MRI-DTI abnormalities which in turn correlated with cognitive changes. Even in the absence of concussion, football players may experience repeated BBBD and serum surges of the potential auto-antigen S100B. The correlation of serum S100B, auto-antibodies and DTI changes support a link between repeated BBBD and future risk for cognitive changes. PMID:23483891

  14. Angiogenesis is associated with blood-brain barrier permeability in temporal lobe epilepsy.

    PubMed

    Rigau, Valérie; Morin, Mélanie; Rousset, Marie-Claude; de Bock, Frédéric; Lebrun, Aurore; Coubes, Philippe; Picot, Marie-Christine; Baldy-Moulinier, Michel; Bockaert, Joël; Crespel, Arielle; Lerner-Natoli, Mireille

    2007-07-01

    Previous studies from our group, focusing on neuro-glial remodelling in human temporal lobe epilepsy (TLE), have shown the presence of immature vascular cells in various areas of the hippocampus. Here, we investigated angiogenic processes in hippocampi surgically removed from adult patients suffering from chronic intractable TLE, with various aetiologies. We compared hippocampi from TLE patients to hippocampi obtained after surgery or autopsy from non-epileptic patients (NE). We quantified the vascular density, checked for the expression of angiogenic factors and their receptors and looked for any blood-brain barrier (BBB) leakage. We used a relevant model of rat limbic epilepsy, induced by lithium-pilocarpine treatment, to understand the sequence of events. In humans, the vessel density was significantly higher in TLE than in NE patients. This was neither dependent on the aetiology nor on the degree of neuronal loss, but was positively correlated with seizure frequency. In the whole hippocampus, we observed many complex, tortuous microvessels. In the dentate gyrus, when the granular layer was dispersed, long microvessels appeared radially orientated. Vascular endothelial factor (VEGF) and tyrosine kinase receptors were detected in different types of cells. An impairment of the BBB was demonstrated by the loss of tight junctions and by Immunoglobulines G (IgG) leakage and accumulation in neurons. In the rat model of TLE, VEGF over-expression and BBB impairment occurred early after status epilepticus, followed by a progressive increase in vascularization. In humans and rodents, angiogenic processes and BBB disruption were still obvious in the chronic focus, probably activated by recurrent seizures. We suggest that the persistent leakage of serum IgG in the interstitial space and their uptake by neurons may participate in hypoperfusion and in neuronal dysfunction occurring in TLE. PMID:17533168

  15. Transcranial direct current stimulation transiently increases the blood-brain barrier solute permeability in vivo

    NASA Astrophysics Data System (ADS)

    Shin, Da Wi; Khadka, Niranjan; Fan, Jie; Bikson, Marom; Fu, Bingmei M.

    2016-03-01

    Transcranial Direct Current Stimulation (tDCS) is a non-invasive electrical stimulation technique investigated for a broad range of medical and performance indications. Whereas prior studies have focused exclusively on direct neuron polarization, our hypothesis is that tDCS directly modulates endothelial cells leading to transient changes in blood-brain-barrier (BBB) permeability (P) that are highly meaningful for neuronal activity. For this, we developed state-of-the-art imaging and animal models to quantify P to various sized solutes after tDCS treatment. tDCS was administered using a constant current stimulator to deliver a 1mA current to the right frontal cortex of rat (approximately 2 mm posterior to bregma and 2 mm right to sagittal suture) to obtain similar physiological outcome as that in the human tDCS application studies. Sodium fluorescein (MW=376), or FITC-dextrans (20K and 70K), in 1% BSA mammalian Ringer was injected into the rat (SD, 250-300g) cerebral circulation via the ipsilateral carotid artery by a syringe pump at a constant rate of ~3 ml/min. To determine P, multiphoton microscopy with 800-850 nm wavelength laser was applied to take the images from the region of interest (ROI) with proper microvessels, which are 100-200 micron below the pia mater. It shows that the relative increase in P is about 8-fold for small solute, sodium fluorescein, ~35-fold for both intermediate sized (Dex-20k) and large (Dex-70k) solutes, 10 min after 20 min tDCS pretreatment. All of the increased permeability returns to the control after 20 min post treatment. The results confirmed our hypothesis.

  16. Nitric oxide isoenzymes regulate lipopolysaccharide-enhanced insulin transport across the blood-brain barrier.

    PubMed

    Banks, William A; Dohgu, Shinya; Lynch, Jessica L; Fleegal-DeMotta, Melissa A; Erickson, Michelle A; Nakaoke, Ryota; Vo, Than Q

    2008-04-01

    Insulin transported across the blood-brain barrier (BBB) has many effects within the central nervous system. Insulin transport is not static but altered by obesity and inflammation. Lipopolysaccharide (LPS), derived from the cell walls of Gram-negative bacteria, enhances insulin transport across the BBB but also releases nitric oxide (NO), which opposes LPS-enhanced insulin transport. Here we determined the role of NO synthase (NOS) in mediating the effects of LPS on insulin BBB transport. The activity of all three NOS isoenzymes was stimulated in vivo by LPS. Endothelial NOS and inducible NOS together mediated the LPS-enhanced transport of insulin, whereas neuronal NOS (nNOS) opposed LPS-enhanced insulin transport. This dual pattern of NOS action was found in most brain regions with the exception of the striatum, which did not respond to LPS, and the parietal cortex, hippocampus, and pons medulla, which did not respond to nNOS inhibition. In vitro studies of a brain endothelial cell (BEC) monolayer BBB model showed that LPS did not directly affect insulin transport, whereas NO inhibited insulin transport. This suggests that the stimulatory effect of LPS and NOS on insulin transport is mediated through cells of the neurovascular unit other than BECs. Protein and mRNA levels of the isoenzymes indicated that the effects of LPS are mainly posttranslational. In conclusion, LPS affects insulin transport across the BBB by modulating NOS isoenzyme activity. NO released by endothelial NOS and inducible NOS acts indirectly to stimulate insulin transport, whereas NO released by nNOS acts directly on BECs to inhibit insulin transport. PMID:18187549

  17. Spatio-temporal analysis of molecular delivery through the blood brain barrier using focused ultrasound

    NASA Astrophysics Data System (ADS)

    Choi, J. J.; Pernot, M.; Brown, T. R.; Small, S. A.; Konofagou, E. E.

    2007-09-01

    The deposition of gadolinium through ultrasound-induced blood-brain barrier (BBB) openings in the murine hippocampus was investigated. First, wave propagation simulations through the intact mouse skull revealed minimal beam distortion while thermal deposition simulations, at the same sonication parameters used to induce BBB opening in vivo, revealed temperature increases lower than 0.5 °C. The simulation results were validated experimentally in ex vivo skulls (m = 6) and in vitro tissue specimens. Then, in vivo mice (n = 9) were injected with microbubbles (Optison™ 25-50 µl) and sonicated (frequency: 1.525 MHz, pressure amplitudes: 0.5-1.1 MPa, burst duration: 20 ms, duty cycle: 20%, durations: 2-4 shots, 30 s per shot, 30 s interval) at the left hippocampus, through intact skin and skull. Sequential, high-resolution, T1-weighted MRI (9.4 Tesla, in-plane resolution: 75 µm, scan time: 45-180 min) with gadolinium (Omniscan™ 0.5 ml) injected intraperitoneally revealed a threshold of the BBB opening at 0.67 MPa and BBB closing within 28 h from opening. The contrast-enhancement area and gadolinium deposition path were monitored over time and the influence of vessel density, size and location was determined. Sonicated arteries, or their immediate surroundings, depicted greater contrast enhancement than sonicated homogeneous brain tissue regions. In conclusion, gadolinium was delivered through a transiently opened BBB and contained to a specific brain region (i.e., the hippocampus) using a single-element focused ultrasound transducer. It was also found that the amount of gadolinium deposited in the hippocampal region increased with the acoustic pressure and that the spatial distribution of the BBB opening was determined not only by the ultrasound beam, but also by the vasculature of the targeted brain region.

  18. Microbubble Type and Distribution Dependence of Focused Ultrasound Induced Blood Brain Barrier Opening

    PubMed Central

    Wang, Shutao; Samiotaki, Gesthimani; Olumolade, Oluyemi; Feshitan, Jameel A.; Konofagou, Elisa E.

    2014-01-01

    Focused Ultrasound (FUS) in the presence of microbubbles has been used to non-invasively induce reversible blood brain barrier (BBB) opening in both rodents and non-human primates. This study aims at identifying the dependence of the BBB opening properties on the polydisperse microbubble (since all clinically approved microbubbles are polydisperse) type and distribution by using clinically approved UCA (Definity®) and in-house made polydisperse microbubbles (IHP) in mice. A total of 18 C57BL/6 mice (n = 3) were used in this study, and each mouse received either Definity® or IHP microbubbles via tail vein injection. The concentration and size distribution of both the activated Definity® and IHP microbubbles were measured and diluted to 6×108/ml prior to injection. Immediately after the microbubble administration, FUS sonications were carried out with the following parameters: frequency of 1.5 MHz, pulse repetition frequency of 10 Hz, 1000 cycles, in situ peak rarefactional acoustic pressures of 0.3 MPa, 0.45 MPa, and 0.6 MPa for a sonication duration of 60 s. Contrast-enhanced magnetic resonance imaging (MRI) was used to confirm the BBB opening and allowed for image-based analysis. The permeability of the treated region and volumes of BBB opening using the two types of microbubbles did not show significant difference (P > 0.05) for PRPs of 0.45 MPa and 0.6 MPa, while IHP microbubbles showed significantly higher permeability and volume of opening (P < 0.05) at the relatively lower pressure of 0.3 MPa. The results from this study indicate that the microbubble type and distribution could have significant effects on the FUS-induced BBB opening at lower, but less important at higher, pressure levels, possibly due to the stable cavitation that governs the former. This difference may have become less significant at higher FUS pressure levels where inertial cavitation typically occurs. PMID:24239362

  19. The rights and wrongs of blood-brain barrier permeability studies: a walk through 100 years of history

    PubMed Central

    Saunders, Norman R.; Dreifuss, Jean-Jacques; Dziegielewska, Katarzyna M.; Johansson, Pia A.; Habgood, Mark D.; Møllgård, Kjeld; Bauer, Hans-Christian

    2014-01-01

    Careful examination of relevant literature shows that many of the most cherished concepts of the blood-brain barrier are incorrect. These include an almost mythological belief in its immaturity that is unfortunately often equated with absence or at least leakiness in the embryo and fetus. The original concept of a blood-brain barrier is often attributed to Ehrlich; however, he did not accept that permeability of cerebral vessels was different from other organs. Goldmann is often credited with the first experiments showing dye (trypan blue) exclusion from the brain when injected systemically, but not when injected directly into it. Rarely cited are earlier experiments of Bouffard and of Franke who showed methylene blue and trypan red stained all tissues except the brain. The term “blood-brain barrier” “Blut-Hirnschranke” is often attributed to Lewandowsky, but it does not appear in his papers. The first person to use this term seems to be Stern in the early 1920s. Studies in embryos by Stern and colleagues, Weed and Wislocki showed results similar to those in adult animals. These were well-conducted experiments made a century ago, thus the persistence of a belief in barrier immaturity is puzzling. As discussed in this review, evidence for this belief, is of poor experimental quality, often misinterpreted and often not properly cited. The functional state of blood-brain barrier mechanisms in the fetus is an important biological phenomenon with implications for normal brain development. It is also important for clinicians to have proper evidence on which to advise pregnant women who may need to take medications for serious medical conditions. Beliefs in immaturity of the blood-brain barrier have held the field back for decades. Their history illustrates the importance of taking account of all the evidence and assessing its quality, rather than selecting papers that supports a preconceived notion or intuitive belief. This review attempts to right the wrongs

  20. Blood-Brain Barrier Effects of the Fusarium Mycotoxins Deoxynivalenol, 3 Acetyldeoxynivalenol, and Moniliformin and Their Transfer to the Brain

    PubMed Central

    Behrens, Matthias; Hüwel, Sabine; Galla, Hans-Joachim; Humpf, Hans-Ulrich

    2015-01-01

    Background Secondary metabolites produced by Fusarium fungi frequently contaminate food and feed and have adverse effects on human and animal health. Fusarium mycotoxins exhibit a wide structural and biosynthetic diversity leading to different toxicokinetics and toxicodynamics. Several studies investigated the toxicity of mycotoxins, focusing on very specific targets, like the brain. However, it still remains unclear how fast mycotoxins reach the brain and if they impair the integrity of the blood-brain barrier. This study investigated and compared the effects of the Fusarium mycotoxins deoxynivalenol, 3-acetyldeoxynivalenol and moniliformin on the blood-brain barrier. Furthermore, the transfer properties to the brain were analyzed, which are required for risk assessment, including potential neurotoxic effects. Methods Primary porcine brain capillary endothelial cells were cultivated to study the effects of the examined mycotoxins on the blood-brain barrier in vitro. The barrier integrity was monitored by cellular impedance spectroscopy and 14C radiolabeled sucrose permeability measurements. The distribution of the applied toxins between blood and brain compartments of the cell monolayer was analyzed by high performance liquid chromatography-mass spectrometry to calculate transfer rates and permeability coefficients. Results Deoxynivalenol reduced the barrier integrity and caused cytotoxic effects at 10 μM concentrations. Slight alterations of the barrier integrity were also detected for 3-acetyldeoxynivalenol. The latter was transferred very quickly across the barrier and additionally cleaved to deoxynivalenol. The transfer of deoxynivalenol and moniliformin was slower, but clearly exceeded the permeability of the negative control. None of the compounds was enriched in one of the compartments, indicating that no efflux transport protein is involved in their transport. PMID:26600019

  1. Radiation-Induced Astrogliosis and Blood-Brain Barrier Damage Can Be Abrogated Using Anti-TNF Treatment

    SciTech Connect

    Wilson, Christy M.; Gaber, M. Waleed Sabek, Omaima M.; Zawaski, Janice A.; Merchant, Thomas E.

    2009-07-01

    Purpose: In this article, we investigate the role of tumor necrosis factor-alpha (TNF) in the initiation of acute damage to the blood-brain barrier (BBB) and brain tissue following radiotherapy (RT) for CNS tumors. Methods and Materials: Intravital microscopy and a closed cranial window technique were used to measure quantitatively BBB permeability to FITC-dextran 4.4-kDa molecules, leukocyte adhesion (Rhodamine-6G) and vessel diameters before and after 20-Gy cranial radiation with and without treatment with anti-TNF. Immunohistochemistry was used to quantify astrogliosis post-RT and immunofluorescence was used to visualize protein expression of TNF and ICAM-1 post-RT. Recombinant TNF (rTNF) was used to elucidate the role of TNF in leukocyte adhesion and vessel diameter. Results: Mice treated with anti-TNF showed significantly lower permeability and leukocyte adhesion at 24 and 48 h post-RT vs. RT-only animals. We observed a significant decrease in arteriole diameters at 48 h post-RT that was inhibited in TNF-treated animals. We also saw a significant increase in activated astrocytes following RT that was significantly lower in the anti-TNF-treated group. In addition, immunofluorescence showed protein expression of TNF and ICAM-1 in the cerebral cortex that was inhibited with anti-TNF treatment. Finally, administration of rTNF induced a decrease in arteriole diameter and a significant increase in leukocyte adhesion in venules and arterioles. Conclusions: TNF plays a significant role in acute changes in BBB permeability, leukocyte adhesion, arteriole diameter, and astrocyte activation following cranial radiation. Treatment with anti-TNF protects the brain's microvascular network from the acute damage following RT.

  2. Experimental cerebral malaria pathogenesis--hemodynamics at the blood brain barrier.

    PubMed

    Nacer, Adéla; Movila, Alexandru; Sohet, Fabien; Girgis, Natasha M; Gundra, Uma Mahesh; Loke, P'ng; Daneman, Richard; Frevert, Ute

    2014-12-01

    Cerebral malaria claims the lives of over 600,000 African children every year. To better understand the pathogenesis of this devastating disease, we compared the cellular dynamics in the cortical microvasculature between two infection models, Plasmodium berghei ANKA (PbA) infected CBA/CaJ mice, which develop experimental cerebral malaria (ECM), and P. yoelii 17XL (PyXL) infected mice, which succumb to malarial hyperparasitemia without neurological impairment. Using a combination of intravital imaging and flow cytometry, we show that significantly more CD8(+) T cells, neutrophils, and macrophages are recruited to postcapillary venules during ECM compared to hyperparasitemia. ECM correlated with ICAM-1 upregulation on macrophages, while vascular endothelia upregulated ICAM-1 during ECM and hyperparasitemia. The arrest of large numbers of leukocytes in postcapillary and larger venules caused microrheological alterations that significantly restricted the venous blood flow. Treatment with FTY720, which inhibits vascular leakage, neurological signs, and death from ECM, prevented the recruitment of a subpopulation of CD45(hi) CD8(+) T cells, ICAM-1(+) macrophages, and neutrophils to postcapillary venules. FTY720 had no effect on the ECM-associated expression of the pattern recognition receptor CD14 in postcapillary venules suggesting that endothelial activation is insufficient to cause vascular pathology. Expression of the endothelial tight junction proteins claudin-5, occludin, and ZO-1 in the cerebral cortex and cerebellum of PbA-infected mice with ECM was unaltered compared to FTY720-treated PbA-infected mice or PyXL-infected mice with hyperparasitemia. Thus, blood brain barrier opening does not involve endothelial injury and is likely reversible, consistent with the rapid recovery of many patients with CM. We conclude that the ECM-associated recruitment of large numbers of activated leukocytes, in particular CD8(+) T cells and ICAM(+) macrophages, causes a severe

  3. C5a alters blood-brain barrier integrity in experimental lupus.

    PubMed

    Jacob, Alexander; Hack, Bradley; Chiang, Eddie; Garcia, Joe G N; Quigg, Richard J; Alexander, Jessy J

    2010-06-01

    The blood-brain barrier (BBB) is a crucial anatomic location in the brain. Its dysfunction complicates many neurodegenerative diseases, from acute conditions, such as sepsis, to chronic diseases, such as systemic lupus erythematosus (SLE). Several studies suggest an altered BBB in lupus, but the underlying mechanism remains unknown. In the current study, we observed a definite loss of BBB integrity in MRL/MpJ-Tnfrsf6(lpr) (MRL/lpr) lupus mice by IgG infiltration into brain parenchyma. In line with this result, we examined the role of complement activation, a key event in this setting, in maintenance of BBB integrity. Complement activation generates C5a, a molecule with multiple functions. Because the expression of the C5a receptor (C5aR) is significantly increased in brain endothelial cells treated with lupus serum, the study focused on the role of C5a signaling through its G-protein-coupled receptor C5aR in brain endothelial cells, in a lupus setting. Reactive oxygen species production increased significantly in endothelial cells, in both primary cells and the bEnd3 cell line treated with lupus serum from MRL/lpr mice, compared with those treated with control serum from MRL(+/+) mice. In addition, increased permeability monitored by changes in transendothelial electrical resistance, cytoskeletal remodeling caused by actin fiber rearrangement, and increased iNOS mRNA expression were observed in bEnd3 cells. These disruptive effects were alleviated by pretreating cells with a C5a receptor antagonist (C5aRant) or a C5a antibody. Furthermore, the structural integrity of the vasculature in MRL/lpr brain was maintained by C5aR inhibition. These results demonstrate the regulation of BBB integrity by the complement system in a neuroinflammatory setting. For the first time, a novel role of C5a in the maintenance of BBB integrity is identified and the potential of C5a/C5aR blockade highlighted as a promising therapeutic strategy in SLE and other neurodegenerative diseases

  4. MR-Guided Unfocused Ultrasound Disruption of the Rat Blood-Brain Barrier

    NASA Astrophysics Data System (ADS)

    Townsend, Kelly A.; King, Randy L.; Zaharchuk, Greg; Pauly, Kim Butts

    2011-09-01

    Therapeutic ultrasound with microbubbles can temporarily disrupt the blood-brain barrier (BBB) for drug delivery. Contrast-enhanced MRI (CE-MRI) can visualize gadolinium passage into the brain, indicating BBB opening. Previous studies used focused ultrasound, which is appropriate for the targeted delivery of drugs. The purpose of this study was to investigate unfocused ultrasound for BBB opening across the whole brain. In 10 rats, gadolinium-based MR contrast agent (Gd; 0.25 ml) was administered concurrent with ultrasound microbubbles (Optison, 0.25 ml) and circulated for 20 sec before sonication. A 753 kHz planar PZT transducer, diameter 1.8 cm, sonicated each rat brain with supplied voltage of 300, 400, or 500 mVpp for 10 sec in continuous wave mode, or at 500 mVpp at 20% duty cycle at 10 Hz for 30-300 sec. After sonication, coronal T1-weighted FSE CE-MRI images were acquired with a 3in surface coil. The imaging protocol was repeated 3-5 times after treatment. One control animal was given Gd and microbubbles, but not sonicated, and the other was given Gd and sonicated without microbubbles. Signal change in ROIs over the muscle, mesencephalon/ventricles, and the cortex/striatum were measured at 3-5 time points up to 36 min after sonication. Signal intensity was converted to % signal change compared to the initial image. In the controls, CE-MRI showed brightening of surrounding structures, but not the brain. In the continuous wave subjects, cortex/striatum signal did not increase, but ventricle/mesenchephalon signal did. Those that received pulsed sonications showed signal increases in both the cortex/striatum and ventricles/mesenchephalon. In conclusion, after pulsed unfocused ultrasound sonication, the BBB is disrupted across the whole brain, including cortex and deep grey matter, while continuous wave sonication affects only the ventricles and possibly deeper structures, without opening the cortex BBB. As time passes, the timeline of Gd passage into the brain

  5. Blood-Brain Barrier Permeability of Normal Appearing White Matter in Relapsing-Remitting Multiple Sclerosis

    PubMed Central

    Lund, Henrik; Krakauer, Martin; Skimminge, Arnold; Sellebjerg, Finn; Garde, Ellen; Siebner, Hartwig R.; Paulson, Olaf B.; Hesse, Dan; Hanson, Lars G.

    2013-01-01

    Background Multiple sclerosis (MS) affects the integrity of the blood-brain barrier (BBB). Contrast-enhanced T1 weighted magnetic resonance imaging (MRI) is widely used to characterize location and extent of BBB disruptions in focal MS lesions. We employed quantitative T1 measurements before and after the intravenous injection of a paramagnetic contrast agent to assess BBB permeability in the normal appearing white matter (NAWM) in patients with relapsing-remitting MS (RR-MS). Methodology/Principal Findings Fifty-nine patients (38 females) with RR-MS undergoing immunomodulatory treatment and nine healthy controls (4 females) underwent quantitative T1 measurements at 3 tesla before and after injection of a paramagnetic contrast agent (0.2 mmol/kg Gd-DTPA). Mean T1 values were calculated for NAWM in patients and total cerebral white matter in healthy subjects for the T1 measurements before and after injection of Gd-DTPA. The pre-injection baseline T1 of NAWM (945±55 [SD] ms) was prolonged in RR-MS relative to healthy controls (903±23 ms, p = 0.028). Gd-DTPA injection shortened T1 to a similar extent in both groups. Mean T1 of NAWM was 866±47 ms in the NAWM of RR-MS patients and 824±13 ms in the white matter of healthy controls. The regional variability of T1 values expressed as the coefficient of variation (CV) was comparable between the two groups at baseline, but not after injection of the contrast agent. After intravenous Gd-DTPA injection, T1 values in NAWM were more variable in RR-MS patients (CV = 0.198±0.046) compared to cerebral white matter of healthy controls (CV = 0.166±0.018, p = 0.046). Conclusions/Significance We found no evidence of a global BBB disruption within the NAWM of RR-MS patients undergoing immunomodulatory treatment. However, the increased variation of T1 values in NAWM after intravenous Gd-DTPA injection points to an increased regional inhomogeneity of BBB function in NAWM in relapsing-remitting MS. PMID:23441184

  6. Melatonin Preserves Blood-Brain Barrier Integrity and Permeability via Matrix Metalloproteinase-9 Inhibition

    PubMed Central

    Alluri, Himakarnika; Wilson, Rickesha L.; Anasooya Shaji, Chinchusha; Wiggins-Dohlvik, Katie; Patel, Savan; Liu, Yang; Peng, Xu; Beeram, Madhava R.; Davis, Matthew L.; Huang, Jason H.; Tharakan, Binu

    2016-01-01

    Microvascular hyperpermeability that occurs at the level of the blood-brain barrier (BBB) often leads to vasogenic brain edema and elevated intracranial pressure following traumatic brain injury (TBI). At a cellular level, tight junction proteins (TJPs) between neighboring endothelial cells maintain the integrity of the BBB via TJ associated proteins particularly, zonula occludens-1 (ZO-1) that binds to the transmembrane TJPs and actin cytoskeleton intracellularly. The pro-inflammatory cytokine, interleukin-1β (IL-1β) as well as the proteolytic enzymes, matrix metalloproteinase-9 (MMP-9) are key mediators of trauma-associated brain edema. Recent studies indicate that melatonin a pineal hormone directly binds to MMP-9 and also might act as its endogenous inhibitor. We hypothesized that melatonin treatment will provide protection against TBI-induced BBB hyperpermeability via MMP-9 inhibition. Rat brain microvascular endothelial cells grown as monolayers were used as an in vitro model of the BBB and a mouse model of TBI using a controlled cortical impactor was used for all in vivo studies. IL-1β (10 ng/mL; 2 hours)-induced endothelial monolayer hyperpermeability was significantly attenuated by melatonin (10 μg/mL; 1 hour), GM6001 (broad spectrum MMP inhibitor; 10 μM; 1 hour), MMP-9 inhibitor-1 (MMP-9 specific inhibitor; 5 nM; 1 hour) or MMP-9 siRNA transfection (48 hours) in vitro. Melatonin and MMP-9 inhibitor-1 pretreatment attenuated IL-1β-induced MMP-9 activity, loss of ZO-1 junctional integrity and f-actin stress fiber formation. IL-1β treatment neither affected ZO-1 protein or mRNA expression or cell viability. Acute melatonin treatment attenuated BBB hyperpermeability in a mouse controlled cortical impact model of TBI in vivo. In conclusion, one of the protective effects of melatonin against BBB hyperpermeability occurs due to enhanced BBB integrity via MMP-9 inhibition. In addition, acute melatonin treatment provides protection against BBB

  7. Mouse Adenovirus Type 1 Early Region 1A Effects on the Blood-Brain Barrier

    PubMed Central

    Tirumuru, Nagaraja; Pretto, Carla D.; Castro Jorge, Luiza A.

    2016-01-01

    ABSTRACT Mouse adenovirus type 1 (MAV-1) infects endothelial cells and disrupts the blood-brain barrier (BBB), causing encephalitis in inbred and outbred mice. Using a virus mutant that does not produce the early region 1A protein E1A, we investigated whether the activity of this known viral transcriptional regulator is needed for BBB disruption and other phenotypes associated with encephalitis. The wild-type (wt) virus and E1A mutant virus caused similar levels of permeability of sodium fluorescein in brains of infected mice. In an in vitro assay of BBB integrity, wt and mutant virus caused similar decreases in transendothelial electrical resistance in primary mouse brain endothelial cell monolayers. These results indicate that E1A protein does not contribute to disruption of BBB integrity in animals or cultured cells. Both wt and E1A mutant virus infection of mice led to similar increases in the activity of two matrix metalloproteinases known to correlate with BBB disruption, MMP2 and MMP9, while causing no increase in the steady-state expression of MMP2 or MMP9 mRNA. In contrast, the amount of MMP3 transcripts increased upon infection by both viruses and to a higher level in infections by the mutant virus lacking E1A protein production. There was no difference in the levels of steady-state expression of mRNA for tight junction proteins among mock virus, wt virus, and mutant virus infections. Thus, the MAV-1 E1A protein does not measurably affect BBB integrity in the parameters assayed, although it reduces the amount of MMP3 mRNA steady-state expression induced in brains upon infection. IMPORTANCE Encephalitis can be caused by viruses, and it is potentially life-threatening because of the vital nature of the brain and the lack of treatment options. MAV-1 produces viral encephalitis in its natural host, providing a model for investigating factors involved in development of encephalitis. MAV-1 infection disrupts the BBB and increases activity of matrix

  8. The role of shear stress in Blood-Brain Barrier endothelial physiology

    PubMed Central

    2011-01-01

    Background One of the most important and often neglected physiological stimuli contributing to the differentiation of vascular endothelial cells (ECs) into a blood-brain barrier (BBB) phenotype is shear stress (SS). With the use of a well established humanized dynamic in vitro BBB model and cDNA microarrays, we have profiled the effect of SS in the induction/suppression of ECs genes and related functions. Results Specifically, we found a significant upregulation of tight and adherens junctions proteins and genes. Trans-endothelial electrical resistance (TEER) and permeability measurements to know substances have shown that SS promoted the formation of a tight and highly selective BBB. SS also increased the RNA level of multidrug resistance transporters, ion channels, and several p450 enzymes. The RNA level of a number of specialized carrier-mediated transport systems (e.g., glucose, monocarboxylic acid, etc.) was also upregulated. RNA levels of modulatory enzymes of the glycolytic pathway (e.g., lactate dehydrogenase) were downregulated by SS while those involved in the Krebs cycle (e.g., lactate and other dehydrogenases) were upregulated. Measurements of glucose consumption versus lactate production showed that SS negatively modulated the glycolytic bioenergetic pathways of glucose metabolism in favor of the more efficient aerobic respiration. BBB ECs are responsive to inflammatory stimuli. Our data showed that SS increased the RNA levels of integrins and vascular adhesion molecules. SS also inhibited endothelial cell cycle via regulation of BTG family proteins encoding genes. This was paralleled by significant increase in the cytoskeletal protein content while that of membrane, cytosol, and nuclear sub-cellular fractions decreased. Furthermore, analysis of 2D gel electrophoresis (which allows identifying a large number of proteins per sample) of EC proteins extracted from membrane sub-cellular endothelial fractions showed that SS increased the expression levels

  9. Mouse Adenovirus Type 1 Early Region 1A Effects on the Blood-Brain Barrier.

    PubMed

    Tirumuru, Nagaraja; Pretto, Carla D; Castro Jorge, Luiza A; Spindler, Katherine R

    2016-01-01

    Mouse adenovirus type 1 (MAV-1) infects endothelial cells and disrupts the blood-brain barrier (BBB), causing encephalitis in inbred and outbred mice. Using a virus mutant that does not produce the early region 1A protein E1A, we investigated whether the activity of this known viral transcriptional regulator is needed for BBB disruption and other phenotypes associated with encephalitis. The wild-type (wt) virus and E1A mutant virus caused similar levels of permeability of sodium fluorescein in brains of infected mice. In an in vitro assay of BBB integrity, wt and mutant virus caused similar decreases in transendothelial electrical resistance in primary mouse brain endothelial cell monolayers. These results indicate that E1A protein does not contribute to disruption of BBB integrity in animals or cultured cells. Both wt and E1A mutant virus infection of mice led to similar increases in the activity of two matrix metalloproteinases known to correlate with BBB disruption, MMP2 and MMP9, while causing no increase in the steady-state expression of MMP2 or MMP9 mRNA. In contrast, the amount of MMP3 transcripts increased upon infection by both viruses and to a higher level in infections by the mutant virus lacking E1A protein production. There was no difference in the levels of steady-state expression of mRNA for tight junction proteins among mock virus, wt virus, and mutant virus infections. Thus, the MAV-1 E1A protein does not measurably affect BBB integrity in the parameters assayed, although it reduces the amount of MMP3 mRNA steady-state expression induced in brains upon infection. IMPORTANCE Encephalitis can be caused by viruses, and it is potentially life-threatening because of the vital nature of the brain and the lack of treatment options. MAV-1 produces viral encephalitis in its natural host, providing a model for investigating factors involved in development of encephalitis. MAV-1 infection disrupts the BBB and increases activity of matrix metalloproteinases in

  10. Chirp- and random-based coded ultrasonic excitation for localized blood-brain barrier opening

    NASA Astrophysics Data System (ADS)

    Kamimura, H. A. S.; Wang, S.; Wu, S.-Y.; Karakatsani, M. E.; Acosta, C.; Carneiro, A. A. O.; Konofagou, E. E.

    2015-10-01

    Chirp- and random-based coded excitation methods have been proposed to reduce standing wave formation and improve focusing of transcranial ultrasound. However, no clear evidence has been shown to support the benefits of these ultrasonic excitation sequences in vivo. This study evaluates the chirp and periodic selection of random frequency (PSRF) coded-excitation methods for opening the blood-brain barrier (BBB) in mice. Three groups of mice (n  =  15) were injected with polydisperse microbubbles and sonicated in the caudate putamen using the chirp/PSRF coded (bandwidth: 1.5-1.9 MHz, peak negative pressure: 0.52 MPa, duration: 30 s) or standard ultrasound (frequency: 1.5 MHz, pressure: 0.52 MPa, burst duration: 20 ms, duration: 5 min) sequences. T1-weighted contrast-enhanced MRI scans were performed to quantitatively analyze focused ultrasound induced BBB opening. The mean opening volumes evaluated from the MRI were 9.38+/- 5.71 mm3, 8.91+/- 3.91 mm3and 35.47+/- 5.10 mm3 for the chirp, random and regular sonications, respectively. The mean cavitation levels were 55.40+/- 28.43 V.s, 63.87+/- 29.97 V.s and 356.52+/- 257.15 V.s for the chirp, random and regular sonications, respectively. The chirp and PSRF coded pulsing sequences improved the BBB opening localization by inducing lower cavitation levels and smaller opening volumes compared to results of the regular sonication technique. Larger bandwidths were associated with more focused targeting but were limited by the frequency response of the transducer, the skull attenuation and the microbubbles optimal frequency range. The coded methods could therefore facilitate highly localized drug delivery as well as benefit other transcranial ultrasound techniques that use higher pressure levels and higher precision to induce the necessary bioeffects in a brain region while avoiding damage to the surrounding healthy tissue.

  11. Fatty Acid-Binding Protein 5 Facilitates the Blood-Brain Barrier Transport of Docosahexaenoic Acid.

    PubMed

    Pan, Yijun; Scanlon, Martin J; Owada, Yuji; Yamamoto, Yui; Porter, Christopher J H; Nicolazzo, Joseph A

    2015-12-01

    The brain has a limited ability to synthesize the essential polyunsaturated fatty acid (PUFA) docosahexaenoic acid (DHA) from its omega-3 fatty acid precursors. Therefore, to maintain brain concentrations of this PUFA at physiological levels, plasma-derived DHA must be transported across the blood-brain barrier (BBB). While DHA is able to partition into the luminal membrane of brain endothelial cells, its low aqueous solubility likely limits its cytosolic transfer to the abluminal membrane, necessitating the requirement of an intracellular carrier protein to facilitate trafficking of this PUFA across the BBB. As the intracellular carrier protein fatty acid-binding protein 5 (FABP5) is expressed at the human BBB, the current study assessed the putative role of FABP5 in the brain endothelial cell uptake and BBB transport of DHA in vitro and in vivo, respectively. hFAPB5 was recombinantly expressed and purified from Escherichia coli C41(DE3) cells and the binding affinity of DHA to hFABP5 assessed using isothermal titration calorimetry. The impact of FABP5 siRNA on uptake of (14)C-DHA into immortalized human brain microvascular endothelial (hCMEC/D3) cells was assessed. An in situ transcardiac perfusion method was optimized in C57BL/6 mice and subsequently used to compare the BBB influx rate (Kin) of (14)C-DHA between FABP5-deficient (FABP5(-/-)) and wild-type (FABP5(+/+)) C57BL/6 mice. DHA bound to hFABP5 with an equilibrium dissociation constant of 155 ± 8 nM (mean ± SEM). FABP5 siRNA transfection decreased hCMEC/D3 mRNA and protein expression of FABP5 by 53.2 ± 5.5% and 44.8 ± 13.7%, respectively, which was associated with a 14.1 ± 2.7% reduction in (14)C-DHA cellular uptake. By using optimized conditions for the in situ transcardiac perfusion (a 1 min preperfusion (10 mL/min) followed by perfusion of (14)C-DHA (1 min)), the Kin of (14)C-DHA was 0.04 ± 0.01 mL/g/s. Relative to FABP5(+/+) mice, the Kin of (14)C-DHA decreased 36.7 ± 12.4% in FABP5(-/-) mice

  12. Experimental Cerebral Malaria Pathogenesis—Hemodynamics at the Blood Brain Barrier

    PubMed Central

    Nacer, Adéla; Movila, Alexandru; Sohet, Fabien; Girgis, Natasha M.; Gundra, Uma Mahesh; Loke, P'ng; Daneman, Richard; Frevert, Ute

    2014-01-01

    Cerebral malaria claims the lives of over 600,000 African children every year. To better understand the pathogenesis of this devastating disease, we compared the cellular dynamics in the cortical microvasculature between two infection models, Plasmodium berghei ANKA (PbA) infected CBA/CaJ mice, which develop experimental cerebral malaria (ECM), and P. yoelii 17XL (PyXL) infected mice, which succumb to malarial hyperparasitemia without neurological impairment. Using a combination of intravital imaging and flow cytometry, we show that significantly more CD8+ T cells, neutrophils, and macrophages are recruited to postcapillary venules during ECM compared to hyperparasitemia. ECM correlated with ICAM-1 upregulation on macrophages, while vascular endothelia upregulated ICAM-1 during ECM and hyperparasitemia. The arrest of large numbers of leukocytes in postcapillary and larger venules caused microrheological alterations that significantly restricted the venous blood flow. Treatment with FTY720, which inhibits vascular leakage, neurological signs, and death from ECM, prevented the recruitment of a subpopulation of CD45hi CD8+ T cells, ICAM-1+ macrophages, and neutrophils to postcapillary venules. FTY720 had no effect on the ECM-associated expression of the pattern recognition receptor CD14 in postcapillary venules suggesting that endothelial activation is insufficient to cause vascular pathology. Expression of the endothelial tight junction proteins claudin-5, occludin, and ZO-1 in the cerebral cortex and cerebellum of PbA-infected mice with ECM was unaltered compared to FTY720-treated PbA-infected mice or PyXL-infected mice with hyperparasitemia. Thus, blood brain barrier opening does not involve endothelial injury and is likely reversible, consistent with the rapid recovery of many patients with CM. We conclude that the ECM-associated recruitment of large numbers of activated leukocytes, in particular CD8+ T cells and ICAM+ macrophages, causes a severe restriction in

  13. The Application of MRI for Depiction of Subtle Blood Brain Barrier Disruption in Stroke

    PubMed Central

    Israeli, David; Tanne, David; Daniels, Dianne; Last, David; Shneor, Ran; Guez, David; Landau, Efrat; Roth, Yiftach; Ocherashvilli, Aharon; Bakon, Mati; Hoffman, Chen; Weinberg, Amit; Volk, Talila; Mardor, Yael

    2011-01-01

    The development of imaging methodologies for detecting blood-brain-barrier (BBB) disruption may help predict stroke patient's propensity to develop hemorrhagic complications following reperfusion. We have developed a delayed contrast extravasation MRI-based methodology enabling real-time depiction of subtle BBB abnormalities in humans with high sensitivity to BBB disruption and high spatial resolution. The increased sensitivity to subtle BBB disruption is obtained by acquiring T1-weighted MRI at relatively long delays (~15 minutes) after contrast injection and subtracting from them images acquired immediately after contrast administration. In addition, the relatively long delays allow for acquisition of high resolution images resulting in high resolution BBB disruption maps. The sensitivity is further increased by image preprocessing with corrections for intensity variations and with whole body (rigid+elastic) registration. Since only two separate time points are required, the time between the two acquisitions can be used for acquiring routine clinical data, keeping the total imaging time to a minimum. A proof of concept study was performed in 34 patients with ischemic stroke and 2 patients with brain metastases undergoing high resolution T1-weighted MRI acquired at 3 time points after contrast injection. The MR images were pre-processed and subtracted to produce BBB disruption maps. BBB maps of patients with brain metastases and ischemic stroke presented different patterns of BBB opening. The significant advantage of the long extravasation time was demonstrated by a dynamic-contrast-enhancement study performed continuously for 18 min. The high sensitivity of our methodology enabled depiction of clear BBB disruption in 27% of the stroke patients who did not have abnormalities on conventional contrast-enhanced MRI. In 36% of the patients, who had abnormalities detectable by conventional MRI, the BBB disruption volumes were significantly larger in the maps than in

  14. Protease activated receptor-1 antagonist ameliorates the clinical symptoms of experimental autoimmune encephalomyelitis via inhibiting breakdown of blood-brain barrier.

    PubMed

    Kim, Ha Neui; Kim, Yu Ri; Ahn, Sung Min; Lee, Sun Kyung; Shin, Hwa Kyoung; Choi, Byung Tae

    2015-11-01

    To evaluate the question of whether protease activated receptor-1 (PAR-1) antagonist is a potential therapeutic target in multiple sclerosis, we treated experimental autoimmune encephalomyelitis (EAE) mice with two PAR-1 antagonists, KC-A0590 and SCH-530348. Treatment with both antagonists resulted in a significant decrease in the clinical characteristics of EAE mice by suppressing demyelination and infiltration of inflammatory cells in the spinal cord and brain, as well as a significantly reducing the increased thrombin and tumor necrosis factor-α. Profound leakage of dextran was observed in the brain of EAE mice. However, treatment with PAR-1 antagonists resulted in the stabilization of vascular endothelial cells and reduced blood-brain barrier breakdown with suppression of inflammatory response. Treatment with PAR-1 antagonists also resulted in down-regulated expression of matrix metalloproteinase-9 and preserved expression of occludin and zonula occludens (ZO)-1 in the brain and their significant expression was confirmed in neurons, astrocytes, and vascular endothelial cells. Finally, endothelial cells and primary cultured astrocytes were treated with PAR-1 antagonists; both antagonists suppressed thrombin-induced breakdown of ZO-1 in endothelial cells and secretion of matrix metalloproteinase-9 in astrocytes. Collectively, our results suggest that PAR-1 antagonist is effective in attenuation of the clinical symptoms of EAE mice by stabilizing the blood-brain barrier and may have therapeutic potential for treatment of multiple sclerosis. PMID:26285165

  15. 7.0-T magnetic resonance imaging characterization of acute blood-brain-barrier disruption achieved with intracranial irreversible electroporation.

    PubMed

    Garcia, Paulo A; Rossmeisl, John H; Robertson, John L; Olson, John D; Johnson, Annette J; Ellis, Thomas L; Davalos, Rafael V

    2012-01-01

    The blood-brain-barrier (BBB) presents a significant obstacle to the delivery of systemically administered chemotherapeutics for the treatment of brain cancer. Irreversible electroporation (IRE) is an emerging technology that uses pulsed electric fields for the non-thermal ablation of tumors. We hypothesized that there is a minimal electric field at which BBB disruption occurs surrounding an IRE-induced zone of ablation and that this transient response can be measured using gadolinium (Gd) uptake as a surrogate marker for BBB disruption. The study was performed in a Good Laboratory Practices (GLP) compliant facility and had Institutional Animal Care and Use Committee (IACUC) approval. IRE ablations were performed in vivo in normal rat brain (n = 21) with 1-mm electrodes (0.45 mm diameter) separated by an edge-to-edge distance of 4 mm. We used an ECM830 pulse generator to deliver ninety 50-μs pulse treatments (0, 200, 400, 600, 800, and 1000 V/cm) at 1 Hz. The effects of applied electric fields and timing of Gd administration (-5, +5, +15, and +30 min) was assessed by systematically characterizing IRE-induced regions of cell death and BBB disruption with 7.0-T magnetic resonance imaging (MRI) and histopathologic evaluations. Statistical analysis on the effect of applied electric field and Gd timing was conducted via Fit of Least Squares with α = 0.05 and linear regression analysis. The focal nature of IRE treatment was confirmed with 3D MRI reconstructions with linear correlations between volume of ablation and electric field. Our results also demonstrated that IRE is an ablation technique that kills brain tissue in a focal manner depicted by MRI (n = 16) and transiently disrupts the BBB adjacent to the ablated area in a voltage-dependent manner as seen with Evan's Blue (n = 5) and Gd administration. PMID:23226293

  16. 7.0-T Magnetic Resonance Imaging Characterization of Acute Blood-Brain-Barrier Disruption Achieved with Intracranial Irreversible Electroporation

    PubMed Central

    Garcia, Paulo A.; Rossmeisl, John H.; Robertson, John L.; Olson, John D.; Johnson, Annette J.; Ellis, Thomas L.; Davalos, Rafael V.

    2012-01-01

    The blood-brain-barrier (BBB) presents a significant obstacle to the delivery of systemically administered chemotherapeutics for the treatment of brain cancer. Irreversible electroporation (IRE) is an emerging technology that uses pulsed electric fields for the non-thermal ablation of tumors. We hypothesized that there is a minimal electric field at which BBB disruption occurs surrounding an IRE-induced zone of ablation and that this transient response can be measured using gadolinium (Gd) uptake as a surrogate marker for BBB disruption. The study was performed in a Good Laboratory Practices (GLP) compliant facility and had Institutional Animal Care and Use Committee (IACUC) approval. IRE ablations were performed in vivo in normal rat brain (n = 21) with 1-mm electrodes (0.45 mm diameter) separated by an edge-to-edge distance of 4 mm. We used an ECM830 pulse generator to deliver ninety 50-μs pulse treatments (0, 200, 400, 600, 800, and 1000 V/cm) at 1 Hz. The effects of applied electric fields and timing of Gd administration (−5, +5, +15, and +30 min) was assessed by systematically characterizing IRE-induced regions of cell death and BBB disruption with 7.0-T magnetic resonance imaging (MRI) and histopathologic evaluations. Statistical analysis on the effect of applied electric field and Gd timing was conducted via Fit of Least Squares with α = 0.05 and linear regression analysis. The focal nature of IRE treatment was confirmed with 3D MRI reconstructions with linear correlations between volume of ablation and electric field. Our results also demonstrated that IRE is an ablation technique that kills brain tissue in a focal manner depicted by MRI (n = 16) and transiently disrupts the BBB adjacent to the ablated area in a voltage-dependent manner as seen with Evan's Blue (n = 5) and Gd administration. PMID:23226293

  17. Progesterone and allopregnanolone attenuate blood-brain barrier dysfunction following permanent focal ischemia by regulating the expression of matrix metalloproteinases

    PubMed Central

    Ishrat, Tauheed; Sayeed, Iqbal; Atif, Fahim; Hua, Fang; Stein, Donald G.

    2010-01-01

    Blood-brain barrier (BBB) breakdown after stroke is linked to the up-regulation of metalloproteinases (MMPs) and inflammation. This study examines the effects of progesterone (PROG) and its neuroactive metabolite allopregnanolone (ALLO) on BBB integrity following permanent middle cerebral artery occlusion (pMCAO). Rats underwent pMCAO by electro-coagulation and received intraperitoneal injections of PROG (8 mg/kg), ALLO (8 mg/kg) or vehicle at 1 h post-occlusion and then subcutaneous injections (8 mg/kg) at 6, 24, and 48 h. MMP activation and expression were analyzed by Western blot, immunohistochemistry and gelatin zymography 72 h post-pMCAO. Occludin1, claudin5, tumor necrosis factor-alpha (TNF-α) and Interleukin-6 (IL-6) were analyzed at 72 h post-pMCAO with Western blots. BBB permeability was measured by Evans blue extravasation and infarct size was evaluated by cresyl violet at 72 h after pMCAO. Ischemic injury significantly (p<0.05) increased the expression of MMP-9, MMP-2, TNF-α and IL-6, and reduced the level of occludin1 and claudin5. These changes were followed by increased infarct size (% contralateral hemisphere) and Evans blue extravasation into the brain indicating compromise of the BBB. PROG and ALLO attenuated BBB disruption and infarct size following pMCAO by reducing MMPs and the inflammatory response and by preventing the degradation of occludin1 and claudin5. We conclude that PROG and ALLO can help to protect BBB disruption following pMCAO. PMID:20816826

  18. Progesterone and allopregnanolone attenuate blood-brain barrier dysfunction following permanent focal ischemia by regulating the expression of matrix metalloproteinases.

    PubMed

    Ishrat, Tauheed; Sayeed, Iqbal; Atif, Fahim; Hua, Fang; Stein, Donald G

    2010-11-01

    Blood-brain barrier (BBB) breakdown after stroke is linked to the up-regulation of metalloproteinases (MMPs) and inflammation. This study examines the effects of progesterone (PROG) and its neuroactive metabolite allopregnanolone (ALLO) on BBB integrity following permanent middle cerebral artery occlusion (pMCAO). Rats underwent pMCAO by electro-coagulation and received intraperitoneal injections of PROG (8 mg/kg), ALLO (8 mg/kg) or vehicle at 1 h post-occlusion and then subcutaneous injections (8 mg/kg) at 6, 24, and 48 h. MMP activation and expression were analyzed by Western blot, immunohistochemistry and gelatin zymography 72 h post-pMCAO. Occludin1, claudin5, tumor necrosis factor-alpha (TNF-α) and Interleukin-6 (IL-6) were analyzed at 72 h post-pMCAO with Western blots. BBB permeability was measured by Evans blue extravasation and infarct size was evaluated by cresyl violet at 72 h after pMCAO. Ischemic injury significantly (p<0.05) increased the expression of MMP-9, MMP-2, TNF-α and IL-6, and reduced the levels of occludin1 and claudin5. These changes were followed by increased infarct size (% contralateral hemisphere) and Evans blue extravasation into the brain indicating compromise of the BBB. PROG and ALLO attenuated BBB disruption and infarct size following pMCAO by reducing MMPs and the inflammatory response and by preventing the degradation of occludin1 and claudin5. We conclude that PROG and ALLO can help to protect BBB disruption following pMCAO. PMID:20816826

  19. Pericytes support neutrophil transmigration via interleukin-8 across a porcine co-culture model of the blood-brain barrier.

    PubMed

    Pieper, Christian; Pieloch, Paulina; Galla, Hans-Joachim

    2013-08-01

    Transmigration of neutrophils across the blood-brain barrier (BBB) to an inflamed brain tissue is an important process during neuronal inflammation. The process of neutrophil activation as well as their way of rolling along the endothelium and their transmigration is quite well understood. Nevertheless, relatively little is known about the fate of neutrophils after they have transmigrated through the endothelium. The role of the other cells of the neurovascular unit in this process is also poorly understood. Here we studied the potential of pericytes to chemo-attract neutrophils under inflammatory conditions. Quantitative real time PCR, western blot analysis, and a chemotaxis assay showed that pericytes are able to chemo-attract neutrophils by interleukin-8 (IL-8) after stimulation with lipopolysaccharides (LPS), tumor necrosis factor-alpha (TNF-α), or interleukin-1beta (IL-1β). Then, a co-culture model consisting of primary porcine brain capillary endothelial cells (PBCECs) and primary porcine brain capillary pericytes (PBCPs) was used to analyze neutrophil transmigration across the BBB. As a model for inflammation, LPS was used and the effects of the cytokines TNF-α, IL-1β, and interferon-gamma (IFN-γ) were analyzed. In general, all stimulants apart from IFN-γ were able to increase transendothelial neutrophil migration. This effect was significantly reduced by a specific inhibitor of matrix metalloproteinases (MMPs)-2 and -9. MMP-2/-9 secretion is expected to decrease adhesion to pericytes and thus support the transmigration of neutrophils. Additionally, in an adhesion experiment, we showed that MMP-2/-9 inhibition significantly enhances the adhesion of neutrophils to pericytes. PMID:23769734

  20. Benefits of agomelatine in behavioral, neurochemical and blood brain barrier alterations in prenatal valproic acid induced autism spectrum disorder.

    PubMed

    Kumar, Hariom; Sharma, B M; Sharma, Bhupesh

    2015-12-01

    Valproic acid administration during gestational period causes behavior and biochemical deficits similar to those observed in humans with autism spectrum disorder. Although worldwide prevalence of autism spectrum disorder has been increased continuously, therapeutic agents to ameliorate the social impairment are very limited. The present study has been structured to investigate the therapeutic potential of melatonin receptor agonist, agomelatine in prenatal valproic acid (Pre-VPA) induced autism spectrum disorder in animals. Pre-VPA has produced reduction in social interaction (three chamber social behavior apparatus), spontaneous alteration (Y-Maze), exploratory activity (Hole board test), intestinal motility, serotonin levels (prefrontal cortex and ileum) and prefrontal cortex mitochondrial complex activity (complex I, II, IV). Furthermore, Pre-VPA has increased locomotor activity (actophotometer), anxiety, brain oxidative stress (thiobarbituric acid reactive species, glutathione, and catalase), nitrosative stress (nitrite/nitrate), inflammation (brain and ileum myeloperoxidase activity), calcium levels and blood brain barrier leakage in animals. Treatment with agomelatine has significantly attenuated Pre-VPA induced reduction in social interaction, spontaneous alteration, exploratory activity intestinal motility, serotonin levels and prefrontal cortex mitochondrial complex activity. Furthermore, agomelatine also attenuated Pre-VPA induced increase in locomotion, anxiety, brain oxidative stress, nitrosative stress, inflammation, calcium levels and blood brain barrier leakage. It is concluded that, Pre-VPA has induced autism spectrum disorder, which was attenuated by agomelatine. Agomelatine has shown ameliorative effect on behavioral, neurochemical and blood brain barrier alteration in Pre-VPA exposed animals. Thus melatonin receptor agonists may provide beneficial therapeutic strategy for managing autism spectrum disorder. PMID:26498253

  1. Vector-Mediated Delivery of a Polyamide ("Peptide") Nucleic Acid Analogue through the Blood-Brain Barrier in vivo

    NASA Astrophysics Data System (ADS)

    Pardridge, William M.; Boado, Ruben J.; Kang, Young-Sook

    1995-06-01

    Polyamide ("peptide") nucleic acids (PNAs) are molecules with antigene and antisense effects that may prove to be effective neuropharmaceuticals if these molecules are enabled to undergo transport through the brain capillary endothelial wall, which makes up the blood-brain barrier in vivo. The model PNA used in the present studies is an 18-mer that is antisense to the rev gene of human immunodeficiency virus type 1 and is biotinylated at the amino terminus and iodinated at a tyrosine residue near the carboxyl terminus. The biotinylated PNA was linked to a conjugate of streptavidin (SA) and the OX26 murine monoclonal antibody to the rat transferrin receptor. The blood-brain barrier is endowed with high transferrin receptor concentrations, enabling the OX26-SA conjugate to deliver the biotinylated PNA to the brain. Although the brain uptake of the free PNA was negligible following intravenous administration, the brain uptake of the PNA was increased at least 28-fold when the PNA was bound to the OX26-SA vector. The brain uptake of the PNA bound to the OX26-SA vector was 0.1% of the injected dose per gram of brain at 60 min after an intravenous injection, approximating the brain uptake of intravenously injected morphine. The PNA bound to the OX26-SA vector retained the ability to bind to synthetic rev mRNA as shown by RNase protection assays. In summary, the present studies show that while the transport of PNAs across the blood-brain barrier is negligible, delivery of these potential neuropharmaceutical drugs to the brain may be achieved by coupling them to vector-mediated peptide-drug delivery systems.

  2. Intra-Arterial Delivery of AAV Vectors to the Mouse Brain After Mannitol Mediated Blood Brain Barrier Disruption

    PubMed Central

    Santillan, Alejandro; Sondhi, Dolan; Dyke, Jonathan P.; Crystal, Ronald G.; Gobin, Y. Pierre; Ballon, Douglas J.

    2014-01-01

    The delivery of therapeutics to neural tissue is greatly hindered by the blood brain barrier (BBB). Direct local delivery via diffusive release from degradable implants or direct intra-cerebral injection can bypass the BBB and obtain high concentrations of the therapeutic in the targeted tissue, however the total volume of tissue that can be treated using these techniques is limited. One treatment modality that can potentially access large volumes of neural tissue in a single treatment is intra-arterial (IA) injection after osmotic blood brain barrier disruption. In this technique, the therapeutic of interest is injected directly into the arteries that feed the target tissue after the blood brain barrier has been disrupted by exposure to a hyperosmolar mannitol solution, permitting the transluminal transport of the therapy. In this work we used contrast enhanced magnetic resonance imaging (MRI) studies of IA injections in mice to establish parameters that allow for extensive and reproducible BBB disruption. We found that the volume but not the flow rate of the mannitol injection has a significant effect on the degree of disruption. To determine whether the degree of disruption we observed with this method was sufficient for delivery of nanoscale therapeutics, we performed IA injections of an adeno-associated viral vector containing the CLN2 gene (AAVrh.10CLN2), which is mutated in the lysosomal storage disorder Late Infantile Neuronal Ceroid Lipofuscinosis (LINCL). We demonstrated that IA injection of AAVrh.10CLN2 after BBB disruption can achieve widespread transgene production in the mouse brain after a single administration. Further, we showed that there exists a minimum threshold of BBB disruption necessary to permit the AAV.rh10 vector to pass into the brain parenchyma from the vascular system. These results suggest that IA administration may be used to obtain widespread delivery of nanoscale therapeutics throughout the murine brain after a single

  3. Intra-arterial delivery of AAV vectors to the mouse brain after mannitol mediated blood brain barrier disruption.

    PubMed

    Foley, Conor P; Rubin, David G; Santillan, Alejandro; Sondhi, Dolan; Dyke, Jonathan P; Gobin, Y Pierre; Crystal, Ronald G; Ballon, Douglas J

    2014-12-28

    The delivery of therapeutics to neural tissue is greatly hindered by the blood brain barrier (BBB). Direct local delivery via diffusive release from degradable implants or direct intra-cerebral injection can bypass the BBB and obtain high concentrations of the therapeutic in the targeted tissue, however the total volume of tissue that can be treated using these techniques is limited. One treatment modality that can potentially access large volumes of neural tissue in a single treatment is intra-arterial (IA) injection after osmotic blood brain barrier disruption. In this technique, the therapeutic of interest is injected directly into the arteries that feed the target tissue after the blood brain barrier has been disrupted by exposure to a hyperosmolar mannitol solution, permitting the transluminal transport of the therapy. In this work we used contrast enhanced magnetic resonance imaging (MRI) studies of IA injections in mice to establish parameters that allow for extensive and reproducible BBB disruption. We found that the volume but not the flow rate of the mannitol injection has a significant effect on the degree of disruption. To determine whether the degree of disruption that we observed with this method was sufficient for delivery of nanoscale therapeutics, we performed IA injections of an adeno-associated viral vector containing the CLN2 gene (AAVrh.10CLN2), which is mutated in the lysosomal storage disorder Late Infantile Neuronal Ceroid Lipofuscinosis (LINCL). We demonstrated that IA injection of AAVrh.10CLN2 after BBB disruption can achieve widespread transgene production in the mouse brain after a single administration. Further, we showed that there exists a minimum threshold of BBB disruption necessary to permit the AAV.rh10 vector to pass into the brain parenchyma from the vascular system. These results suggest that IA administration may be used to obtain widespread delivery of nanoscale therapeutics throughout the murine brain after a single

  4. Neuropsychiatric disease relevance of circulating anti-NMDA receptor autoantibodies depends on blood-brain barrier integrity.

    PubMed

    Hammer, C; Stepniak, B; Schneider, A; Papiol, S; Tantra, M; Begemann, M; Sirén, A-L; Pardo, L A; Sperling, S; Mohd Jofrry, S; Gurvich, A; Jensen, N; Ostmeier, K; Lühder, F; Probst, C; Martens, H; Gillis, M; Saher, G; Assogna, F; Spalletta, G; Stöcker, W; Schulz, T F; Nave, K-A; Ehrenreich, H

    2014-10-01

    In 2007, a multifaceted syndrome, associated with anti-NMDA receptor autoantibodies (NMDAR-AB) of immunoglobulin-G isotype, has been described, which variably consists of psychosis, epilepsy, cognitive decline and extrapyramidal symptoms. Prevalence and significance of NMDAR-AB in complex neuropsychiatric disease versus health, however, have remained unclear. We tested sera of 2817 subjects (1325 healthy, 1081 schizophrenic, 263 Parkinson and 148 affective-disorder subjects) for presence of NMDAR-AB, conducted a genome-wide genetic association study, comparing AB carriers versus non-carriers, and assessed their influenza AB status. For mechanistic insight and documentation of AB functionality, in vivo experiments involving mice with deficient blood-brain barrier (ApoE(-/-)) and in vitro endocytosis assays in primary cortical neurons were performed. In 10.5% of subjects, NMDAR-AB (NR1 subunit) of any immunoglobulin isotype were detected, with no difference in seroprevalence, titer or in vitro functionality between patients and healthy controls. Administration of extracted human serum to mice influenced basal and MK-801-induced activity in the open field only in ApoE(-/-) mice injected with NMDAR-AB-positive serum but not in respective controls. Seropositive schizophrenic patients with a history of neurotrauma or birth complications, indicating an at least temporarily compromised blood-brain barrier, had more neurological abnormalities than seronegative patients with comparable history. A common genetic variant (rs524991, P=6.15E-08) as well as past influenza A (P=0.024) or B (P=0.006) infection were identified as predisposing factors for NMDAR-AB seropositivity. The >10% overall seroprevalence of NMDAR-AB of both healthy individuals and patients is unexpectedly high. Clinical significance, however, apparently depends on association with past or present perturbations of blood-brain barrier function. PMID:23999527

  5. [CURRENT OPPORTUNITIES IN THE IDENTIFICATION OF NOVEL MOLECULAR TARGETS FOR PHARMACOLOGICAL CORRECTION OF BLOOD-BRAIN BARRIER PERMEABILITY].

    PubMed

    Morgun, A V; Ruzaeva, V A; Boitsova, E B; Taranushenko, T E; Martynova, G P; Tohidpour, A; Salmina, A B

    2015-01-01

    Review covers current achievements in the methodology of target discovery and validation for the development of drugs restoring structural and functional integrity of the blood-brain barrier (BBB) in cases of brain injury and neuroinflammation. Some new targets (in the context of BBB permeability) are discussed, which are involved in the regulation of signal transduction involving HIF-1, JNK, NF-κB, Rac, 1 etc., expression of tight-junction proteins, and activity of enzymes producing molecules with pro-inflammatory effects in the BBB cells. PMID:27051929

  6. The blood-brain barrier penetration and distribution of PEGylated fluorescein-doped magnetic silica nanoparticles in rat brain

    SciTech Connect

    Ku, Shuting; Yan, Feng; Wang, Ying; Sun, Yilin; Yang, Nan; Ye, Ling

    2010-04-16

    PEGylated PAMAM conjugated fluorescein-doped magnetic silica nanoparticles (PEGylated PFMSNs) have been synthesized for evaluating their ability across the blood-brain barrier (BBB) and distribution in rat brain. The obtained nanoparticles were characterized by transmission electron microscopy (TEM), thermal gravimetry analyses (TGA), zeta potential ({zeta}-potential) titration, and X-ray photoelectron spectroscopy (XPS). The BBB penetration and distribution of PEGylated PFMSNs and FMSNs in rat brain were investigated not only at the cellular level with Confocal laser scanning microscopy (CLSM), but also at the subcellular level with transmission electron microscopy (TEM). The results provide direct evidents that PEGylated PFMSNs could penetrate the BBB and spread into the brain parenchyma.

  7. Ultrasound-mediated blood-brain barrier disruption for targeted drug delivery in the central nervous system

    NASA Astrophysics Data System (ADS)

    McDannold, Nathan; Zhang, Yongzhi; Power, Chanikarn; Arvanitis, Costas D.; Vykhodtseva, Natalia; Livingstone, Margaret

    2015-05-01

    The physiology of the vasculature in the central nervous system (CNS), which includes the blood-brain barrier (BBB) and other factors, complicates the delivery of most drugs to the brain. Different methods have been used to bypass the BBB, but they have limitations such as being invasive, non-targeted or requiring the formulation of new drugs. Focused ultrasound (FUS), when combined with circulating microbubbles, is a noninvasive method to locally and transiently disrupt the BBB at discrete targets. The method presents new opportunities for the use of drugs and for the study of the brain.

  8. Smuggling Drugs into the Brain: An Overview of Ligands Targeting Transcytosis for Drug Delivery across the Blood-Brain Barrier.

    PubMed

    Georgieva, Julia V; Hoekstra, Dick; Zuhorn, Inge S

    2014-01-01

    The blood-brain barrier acts as a physical barrier that prevents free entry of blood-derived substances, including those intended for therapeutic applications. The development of molecular Trojan horses is a promising drug targeting technology that allows for non-invasive delivery of therapeutics into the brain. This concept relies on the application of natural or genetically engineered proteins or small peptides, capable of specifically ferrying a drug-payload that is either directly coupled or encapsulated in an appropriate nanocarrier, across the blood-brain barrier via receptor-mediated transcytosis. Specifically, in this process the nanocarrier-drug system ("Trojan horse complex") is transported transcellularly across the brain endothelium, from the blood to the brain interface, essentially trailed by a native receptor. Naturally, only certain properties would favor a receptor to serve as a transporter for nanocarriers, coated with appropriate ligands. Here we briefly discuss brain microvascular endothelial receptors that have been explored until now, highlighting molecular features that govern the efficiency of nanocarrier-mediated drug delivery into the brain. PMID:25407801

  9. Mechanisms of microwave-induced blood-brain barrier alterations. Final report 1 Apr 1978-31 Aug 1980

    SciTech Connect

    Lin, J.C.

    1980-09-01

    This investigation was designed to study the mechanisms of interaction between microwaves and the blood-brain barrier and was aimed at correlating changes of blood-brain barrier permeability with the quantity and distribution of absorbed microwave energy inside the brain of adult Wistar rats under sodium pentobarbital anesthesia. Through use of thermographic methods and a direct-contact applicator at the animal's head, the pattern of absorbed microwave energy was determined. Indwelling catheters were placed in the femoral vein. Evans blue in isotonic saline were used as a visual indicator of barrier permeation. Irradiation with pulsed 2450-MHz microwaves for 20 min at average power densities of 0.5 to 2600 mW/squared, which resulted in average specific absorption rates (SARs) of 0.04 to 200 mW/g in the brain, did not produce staining, except in regions that normally are highly permeable. When the incident power density was increased to 3000 mW/squared (SAR of 240 mW/g), extravasation of Evans blue could be seen in the cortex, hippocampus and midbrain.

  10. Internal benchmarking of a human blood-brain barrier cell model for screening of nanoparticle uptake and transcytosis.

    PubMed

    Ragnaill, Michelle Nic; Brown, Meredith; Ye, Dong; Bramini, Mattia; Callanan, Sean; Lynch, Iseult; Dawson, Kenneth A

    2011-04-01

    Transport of drugs across the blood-brain barrier, which protects the brain from harmful agents, is considered the holy grail of targeted delivery, due to the extreme effectiveness of this barrier at preventing passage of non-essential molecules through to the brain. This has caused severe limitations for therapeutics for many brain-associated diseases, such as HIV and neurodegenerative diseases. Nanomaterials, as a result of their small size (in the order of many protein-lipid clusters routinely transported by cells) and their large surface area (which acts as a scaffold for proteins thereby rendering nanoparticles as biological entities) offer great promise for neuro-therapeutics. However, in parallel with developing neuro-therapeutic applications based on nanotechnology, it is essential to ensure their safety and long-term consequences upon reaching the brain. One approach to determining safe application of nanomaterials in biology is to obtain a deep mechanistic understanding of the interactions between nanomaterials and living systems (bionanointeractions). To this end, we report here on the establishment and internal round robin validation of a human cell model of the blood-brain barrier for use as a tool for screening nanoparticles interactions, and assessing the critical nanoscale parameters that determine transcytosis. PMID:21236340

  11. a Study of Blood-Brain Barrier Permeability Variations in Vivo Using Magnetic Resonance Imaging.

    NASA Astrophysics Data System (ADS)

    Neuder, Michelle Sandy

    We have measured non-invasively the transcapillary transport of water and an extracellular marker, gadolinium diethylenetriamine pentaacetate (Gd-DTPA) in the living brain using conventional and rapid NMR imaging strategies. Detection of water exchange post-contrast and of Gd-DTPA leakage across an intact and hyperosmotically-disrupted blood-brain barrier (BBB) were investigated in animal models. The development of high speed magnetic resonance imaging methods provides a tool for measuring short-term variations in BBB permeability in vivo over relatively short experimental time periods, and for determining the influence of these permeability changes on other physiologic parameters. The overall aims of this thesis have been to exploit the high temporal resolution available with a fast scanning technique, echo-planar imaging, to (1) quantitate the permeability of the BBB to water before and after altering the exchange capacity of the capillary bed, (2) use these measurements to model small, reversible changes in permeability to Gd-DTPA in terms of the post -contrast relaxation characteristics of the blood and tissue spaces during the first- and multiple-pass phases of transport, and (3) explore the influence of an increased permeability on the first-pass kinetic behavior. We initially present the theory of two-site water exchange, a modification of the Bloch equations used to examine time-dependent changes in the nuclear spin magnetization with time. The solutions of these equations for our particular imaging experiment were initially validated in a well-characterized dialysis chamber in order to demonstrate the sensitivity of the experiment to detecting biexponential signal decay. Upon validating the theory, we measured water exchange times in vivo in rodent and canine brain. A biexponential model of NMR signal decay was used to determine both the intravascular blood volume and intravascular water lifetime. Mannitol, a hyperosmotic solution, which can increase BBB

  12. BACE-1 is expressed in the blood-brain barrier endothelium and is upregulated in a murine model of Alzheimer's disease.

    PubMed

    Devraj, Kavi; Poznanovic, Slobodan; Spahn, Christoph; Schwall, Gerhard; Harter, Patrick N; Mittelbronn, Michel; Antoniello, Katia; Paganetti, Paolo; Muhs, Andreas; Heilemann, Mike; Hawkins, Richard A; Schrattenholz, André; Liebner, Stefan

    2016-07-01

    Endothelial cells of the blood-brain barrier form a structural and functional barrier maintaining brain homeostasis via paracellular tight junctions and specific transporters such as P-glycoprotein. The blood-brain barrier is responsible for negligible bioavailability of many neuroprotective drugs. In Alzheimer's disease, current treatment approaches include inhibitors of BACE-1 (β-site of amyloid precursor protein cleaving enzyme), a proteinase generating neurotoxic β-amyloid. It is known that BACE-1 is highly expressed in endosomes and membranes of neurons and glia. We now provide evidence that BACE-1 is expressed in blood-brain barrier endothelial cells of human, mouse, and bovine origin. We further show its predominant membrane localization by 3D-dSTORM super-resolution microscopy, and by biochemical fractionation that further shows an abluminal distribution of BACE-1 in brain microvessels. We confirm its functionality in processing APP in primary mouse brain endothelial cells. In an Alzheimer's disease mouse model we show that BACE-1 is upregulated at the blood-brain barrier compared to healthy controls. We therefore suggest a critical role for BACE-1 at the blood-brain barrier in β-amyloid generation and in vascular aspects of Alzheimer's disease, particularly in the development of cerebral amyloid angiopathy. PMID:26661166

  13. Acanthamoeba produces disseminated infection in locusts and traverses the locust blood-brain barrier to invade the central nervous system

    PubMed Central

    2010-01-01

    Background Many aspects of Acanthamoeba granulomatous encephalitis remain poorly understood, including host susceptibility and chronic colonization which represent important features of the spectrum of host-pathogen interactions. Previous studies have suggested locusts as a tractable model in which to study Acanthamoeba pathogenesis. Here we determined the mode of parasite invasion of the central nervous system (CNS). Results Using Acanthamoeba isolates belonging to the T1 and T4 genotypes, the findings revealed that amoebae induced sickness behaviour in locusts, as evidenced by reduced faecal output and weight loss and, eventually, leading to 100% mortality. Significant degenerative changes of various tissues were observed by histological sectioning. Both isolates produced disseminated infection, with viable amoebae being recovered from various tissues. Histological examination of the CNS showed that Acanthamoeba invaded the locust CNS, and this is associated with disruption of the perineurium cell/glial cell complex, which constitutes the locust blood-brain barrier. Conclusions This is the first study to demonstrate that Acanthamoeba invades locust brain by modulating the integrity of the insect's blood-brain barrier, a finding that is consistent with the human infection. These observations support the idea that locusts provide a tractable model to study Acanthamoeba encephalitis in vivo. In this way the locust model may generate potentially useful leads that can be tested subsequently in mammalian systems, thus replacing the use of vertebrates at an early stage, and reducing the numbers of mammals required overall. PMID:20615207

  14. Liposomes Coloaded with Elacridar and Tariquidar To Modulate the P-Glycoprotein at the Blood-Brain Barrier.

    PubMed

    Nieto Montesinos, Rita; Béduneau, Arnaud; Lamprecht, Alf; Pellequer, Yann

    2015-11-01

    This study prepared three liposomal formulations coloaded with elacridar and tariquidar to overcome the P-glycoprotein-mediated efflux at the blood-brain barrier. Their pharmacokinetics, brain distribution, and impact on the model P-glycoprotein substrate, loperamide, were compared to those for the coadministration of free elacridar plus free tariquidar. After intravenous administration in rats, elacridar and tariquidar in conventional liposomes were rapidly cleared from the bloodstream. Their low levels in the brain did not improve the loperamide brain distribution. Although elacridar and tariquidar in PEGylated liposomes exhibited 2.6 and 1.9 longer half-lives than free elacridar and free tariquidar, respectively, neither their Kp for the brain nor the loperamide brain distribution was improved. However, the conjugation of OX26 F(ab')2 fragments to PEGylated liposomes increased the Kps for the brain of elacridar and tariquidar by 1.4- and 2.1-fold, respectively, in comparison to both free P-gp modulators. Consequently, the Kp for the brain of loperamide increased by 2.7-fold. Moreover, the plasma pharmacokinetic parameters and liver distribution of loperamide were not modified by the PEGylated OX26 F(ab')2 immunoliposomes. Thus, this formulation represents a promising tool for modulating the P-glycoprotein-mediated efflux at the blood-brain barrier and could improve the brain uptake of any P-glycoprotein substrate that is intended to treat central nervous system diseases. PMID:26390138

  15. Transient blood-brain barrier permeability following profound temporary global ischemia: an experimental study using /sup 14/C-AIB

    SciTech Connect

    Dobbin, J.; Crockard, H.A.; Ross-Russell, R.

    1989-02-01

    The influence of reperfusion after profound incomplete forebrain ischemia on blood-brain barrier (BBB) permeability to a small protein tracer was studied in male Sprague-Dawley rats. The mean cortical blood to brain transfer constant (Ki) for /sup 14/C-amino isobutyric acid (AIB) was significantly greater at 3 and 6 h of reperfusion, 2.5 times the mean values of controls (p less than 0.05) (2.5 microliter g-1 min-1 and 1.0 microliters g-1 min-1 respectively), but had returned to control values after reperfusion for 24 h. Analysis of distribution of Ki values showed that following 15 min and 30 min of profound ischemia, there was a significant increase in transfer of AIB across the blood-brain barrier (BBB) after recirculation for up to 6 h, though there was no evidence of protein extravasation as assessed by Evans Blue (EB) dye. After 24 h of reperfusion, the BBB to AIB was restored, and Ki values had returned to control values. It is concluded that following transient global ischemia, the BBB may recover rapidly.

  16. Deoxycholic Acid as a Modifier of the Permeation of Gliclazide through the Blood Brain Barrier of a Rat.

    PubMed

    Lalić-Popović, Mladena; Vasović, Velibor; Milijašević, Boris; Goločorbin-Kon, Svetlana; Al-Salami, Hani; Mikov, Momir

    2013-01-01

    Major problem for diabetic patients represents damage of blood vessels and the oxidative stress of the brain cells due to increased concentration of free radicals and poor nutrition of brain cells. Gliclazide has antioxidative properties and poor blood brain barrier (BBB) penetration. Bile acids are known for their hypoglycemic effect and as promoters of drug penetration across biological membranes. Accordingly, the aim of this study is to investigate whether the bile acid (deoxycholic acid) can change the permeation of gliclazide, through the blood brain barrier of a rat model type-1 diabetes. Twenty-four male Wistar rats were randomly allocated to four groups, of which, two were given alloxan intraperitoneally (100 mg/kg) to induce diabetes. One diabetic group and one healthy group were given a bolus gliclazide intra-arterially (20 mg/kg), while the other two groups apart from gliclazide got deoxycholic acid (4 mg/kg) subcutaneously. Blood samples were collected 30, 60, 150, and 240 seconds after dose, brain tissues were immediately excised and blood glucose and gliclazide concentrations were measured. Penetration of gliclazide in groups without deoxycholic acid pretreatment was increased in diabetic animals compared to healthy animals. Also in both, the healthy and diabetic animals, deoxycholic acid increased the permeation of gliclazide through that in BBB. PMID:23671878

  17. Penetration of Drugs through the Blood-Cerebrospinal Fluid/Blood-Brain Barrier for Treatment of Central Nervous System Infections†

    PubMed Central

    Nau, Roland; Sörgel, Fritz; Eiffert, Helmut

    2010-01-01

    Summary: The entry of anti-infectives into the central nervous system (CNS) depends on the compartment studied, molecular size, electric charge, lipophilicity, plasma protein binding, affinity to active transport systems at the blood-brain/blood-cerebrospinal fluid (CSF) barrier, and host factors such as meningeal inflammation and CSF flow. Since concentrations in microdialysates and abscesses are not frequently available for humans, this review focuses on drug CSF concentrations. The ideal compound to treat CNS infections is of small molecular size, is moderately lipophilic, has a low level of plasma protein binding, has a volume of distribution of around 1 liter/kg, and is not a strong ligand of an efflux pump at the blood-brain or blood-CSF barrier. When several equally active compounds are available, a drug which comes close to these physicochemical and pharmacokinetic properties should be preferred. Several anti-infectives (e.g., isoniazid, pyrazinamide, linezolid, metronidazole, fluconazole, and some fluoroquinolones) reach a CSF-to-serum ratio of the areas under the curves close to 1.0 and, therefore, are extremely valuable for the treatment of CNS infections. In many cases, however, pharmacokinetics have to be balanced against in vitro activity. Direct injection of drugs, which do not readily penetrate into the CNS, into the ventricular or lumbar CSF is indicated when other effective therapeutic options are unavailable. PMID:20930076

  18. Comparison of the effects of some thiamine analogues upon thiamine transport across the blood-brain barrier of the rat.

    PubMed Central

    Greenwood, J; Pratt, O E

    1985-01-01

    The flux of thiamine from the blood into the brain has been measured by a specially devised procedure in which a steady raised level of the vitamin, with or without radioactive labelling, was achieved rapidly and maintained steadily in the circulating blood plasma. This was done by a single rapid I.V. injection followed by a continuous injection given at a rate adjusted according to a pre-determined programme, so as to replace the injected material at the rate at which it had been found to leave the circulation in preliminary experiments. A series of four chemical analogues of thiamine were given to see how each affected the flux of thiamine into the brain and the findings are compared with those for a fifth analogue studied in previous work. Pyrithiamine, thiamine disulphide and acetylthiamine, like amprolium, inhibited thiamine transport across the blood-brain barrier. Kinetic analysis shows that they compete mainly for the saturable component of thiamine flux across the blood-brain barrier, with only a slight inhibition of the non-saturable component, most clearly seen with pyrithiamine. Oxythiamine, despite its close chemical similarity to thiamine did not have any significant effect upon the flux of the vitamin into the brain. These findings help to explain the efficacy of pyrithiamine administration, especially in conjunction with a thiamine-deficient diet, in rapidly producing central neurological signs of deficiency. PMID:4093890

  19. Vascular Endothelial Growth Factor Increases during Blood-Brain Barrier-Enhanced Permeability Caused by Phoneutria nigriventer Spider Venom

    PubMed Central

    Mendonça, Monique C. P.; Soares, Edilene S.; Stávale, Leila M.; Kalapothakis, Evanguedes; Cruz-Höfling, Maria Alice

    2014-01-01

    Phoneutria nigriventer spider accidental envenomation provokes neurotoxic manifestations, which when critical, results in epileptic-like episodes. In rats, P. nigriventer venom (PNV) causes blood-brain barrier breakdown (BBBb). The PNV-induced excitotoxicity results from disturbances on Na+, K+ and Ca2+ channels and glutamate handling. The vascular endothelial growth factor (VEGF), beyond its angiogenic effect, also, interferes on synaptic physiology by affecting the same ion channels and protects neurons from excitotoxicity. However, it is unknown whether VEGF expression is altered following PNV envenomation. We found that adult and neonates rats injected with PNV showed immediate neurotoxic manifestations which paralleled with endothelial occludin, β-catenin, and laminin downregulation indicative of BBBb. In neonate rats, VEGF, VEGF mRNA, and Flt-1 receptors, glutamate decarboxylase, and calbindin-D28k increased in Purkinje neurons, while, in adult rats, the BBBb paralleled with VEGF mRNA, Flk-1, and calbindin-D28k increases and Flt-1 decreases. Statistically, the variable age had a role in such differences, which might be due to age-related unequal maturation of blood-brain barrier (BBB) and thus differential cross-signaling among components of the glial neurovascular unit. The concurrent increases in the VEGF/Flt-1/Flk-1 system in the cerebellar neuron cells and the BBBb following PNV exposure might imply a cytokine modulation of neuronal excitability consequent to homeostatic perturbations induced by ion channels-acting PNV neuropeptides. Whether such modulation represents neuroprotection needs further investigation. PMID:25247186

  20. Kinetic modeling of 52Fe/52mMn-citrate at the blood-brain barrier by positron emission tomography.

    PubMed

    Calonder, C; Würtenberger, P I; Maguire, R P; Pellikka, R; Leenders, K L

    1999-11-01

    The kinetics of iron at the blood-brain barrier of the monkey were studied in vivo using positron emission tomography (PET) and the tracer 52Fe/52mMn-citrate. 52mMn is the beta(+)-emitting daughter nuclide of 52Fe and therefore contributes to the observed signal and background in the PET images and may influence the quantification of physiological relevant iron parameters. The kinetics of pure (52m)Mn-citrate at the blood-brain barrier of the monkey were studied experimentally, and the analysis of the data with a reasonable compartment model led to equal efflux and influx parameters for Mn (1.35 +/- 0.3 x 10(-2) min(-1)). By using complexes between Mn and diethylenetriaminepentaacetic acid, the validity of the proposed model could be confirmed. To describe the observed kinetics of 52Fe/(52m)Mn-citrate, the manganese model was coupled to an iron model, which finally allowed the quantification of two iron-specific parameters: an input rate into global brain tissue of 7.15 +/- 2.6 x 10(-4) min(-1) and a time delay of roughly 24 min to account for the observed activities. The simpler linearization procedure has been proposed and could be applied to all our data sets and is able to replace the complicated nonlinear iron/manganese tracer kinetic model neglecting any influence of manganese on the analysis. PMID:10537064

  1. Mast cells promote blood brain barrier breakdown and neutrophil infiltration in a mouse model of focal cerebral ischemia

    PubMed Central

    McKittrick, Craig M; Lawrence, Catherine E; Carswell, Hilary V O

    2015-01-01

    Blood brain barrier (BBB) breakdown and neuroinflammation are key events in ischemic stroke morbidity and mortality. The present study investigated the effects of mast cell deficiency and stabilization on BBB breakdown and neutrophil infiltration in mice after transient middle cerebral artery occlusion (tMCAo). Adult male C57BL6/J wild type (WT) and mast cell-deficient (C57BL6/J KitWsh/Wsh (Wsh)) mice underwent tMCAo and BBB breakdown, brain edema and neutrophil infiltration were examined after 4 hours of reperfusion. Blood brain barrier breakdown, brain edema, and neutrophil infiltration were significantly reduced in Wsh versus WT mice (P<0.05). These results were reproduced pharmacologically using mast cell stabilizer, cromoglycate. Wild-type mice administered cromoglycate intraventricularly exhibited reduced BBB breakdown, brain edema, and neutrophil infiltration versus vehicle (P<0.05). There was no effect of cromoglycate versus vehicle in Wsh mice, validating specificity of cromoglycate on brain mast cells. Proteomic analysis in Wsh versus WT indicated that effects may be via expression of endoglin, endothelin-1, and matrix metalloproteinase-9. Using an in vivo model of mast cell deficiency, this is the first study showing that mast cells promote BBB breakdown in focal ischemia in mice, and opens up future opportunities for using mice to identify specific mechanisms of mast cell-related BBB injury. PMID:25564235

  2. Investigating the passage of tetramethylpyrazine-loaded liposomes across blood-brain barrier models in vitro and ex vivo.

    PubMed

    Xia, Hongmei; Cheng, Zhiqing; Cheng, Yongfeng; Xu, Yinxiang

    2016-12-01

    Tetramethylpyrazine (TMP) is a natural product extracted from Rhizoma Chuanxiong. Liposomes are an excellent delivery method that is suitable for the penetration of the blood-brain barrier (BBB). TMP-loaded liposomes are suitable for the treatment of cerebral ischemic diseases. We measured the morphology, particle size, zeta-potential, entrapment efficiency, and content of TMP-loaded liposome. The electrochemical method was adopted to determine entrapment efficiency for the first time. In addition, their diffusion through BBB models, which were built not only by in vitro cell culture but also by the ex vivo mouse subcutaneous-mucous-membrane (mSMM) method, was explored. The results showed that TMP and TMP-loaded liposomes could effectively permeate both BBB models. Therefore, the study indicated that liposomes were a novel carrier that could deliver TMP across the body barrier models and then release TMP slowly. PMID:27612797

  3. Brain damage from sup 125 I brachytherapy evaluated by MR imaging, a blood-brain barrier tracer, and light and electron microscopy in a rat model

    SciTech Connect

    Bernstein, M.; Marotta, T.; Stewart, P.; Glen, J.; Resch, L.; Henkelman, M. )

    1990-10-01

    Changes in normal rat brain were studied acutely, and at 3, 6, 9, and 12 months following interstitial brachytherapy with high-activity {sup 125}I seeds. An 80-Gy radiation dose was administered to an area with a 5.5-mm radius. Effects were measured with magnetic resonance (MR) imaging (with and without gadolinium enhancement), leakage of horseradish peroxidase (HRP), electron microscopy, and light microscopy. Significant histological damage was seen at radiation doses above 295 Gy, and breakdown of the blood-brain barrier was observed only in tissue receiving a dose of 165 Gy or greater. Blood-brain barrier breakdown increased up to the 6-month time point, and thereafter appeared to stabilize or decrease. The area of blood-brain barrier disruption indicated by gadolinium-enhanced MR imaging was greater than that indicated by leakage of HRP.

  4. Ictal lack of binding to brain parenchyma suggests integrity of the blood-brain barrier for 11C-dihydroergotamine during glyceryl trinitrate-induced migraine.

    PubMed

    Schankin, Christoph J; Maniyar, Farooq H; Seo, Youngho; Kori, Shashidar; Eller, Michael; Chou, Denise E; Blecha, Joseph; Murphy, Stephanie T; Hawkins, Randall A; Sprenger, Till; VanBrocklin, Henry F; Goadsby, Peter J

    2016-07-01

    SEE DREIER DOI 101093/AWW112 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE: For many decades a breakdown of the blood-brain barrier has been postulated to occur in migraine. Hypothetically this would facilitate access of medications, such as dihydroergotamine or triptans, to the brain despite physical properties otherwise restricting their entry. We studied the permeability of the blood-brain barrier in six migraineurs and six control subjects at rest and during acute glyceryl trinitrate-induced migraine attacks using positron emission tomography with the novel radioligand (11)C-dihydroergotamine, which is chemically identical to pharmacologically active dihydroergotamine. The influx rate constant Ki, average dynamic image and time activity curve were assessed using arterial blood sampling and served as measures for receptor binding and thus blood-brain barrier penetration. At rest, there was binding of (11)C-dihydroergotamine in the choroid plexus, pituitary gland, and venous sinuses as expected from the pharmacology of dihydroergotamine. However, there was no binding to the brain parenchyma, including the hippocampus, the area with the highest density of the highest-affinity dihydroergotamine receptors, and the raphe nuclei, a postulated brainstem site of action during migraine, suggesting that dihydroergotamine is not able to cross the blood-brain barrier. This binding pattern was identical in migraineurs during glyceryl trinitrate-induced migraine attacks as well as in matched control subjects. We conclude that (11)C-dihydroergotamine is unable to cross the blood-brain barrier interictally or ictally demonstrating that the blood-brain barrier remains tight for dihydroergotamine during acute glyceryl trinitrate-induced migraine attacks. PMID:27234268

  5. Tightness of the blood-brain barrier and evidence for brain interstitial fluid flow in the cuttlefish, Sepia officinalis.

    PubMed Central

    Abbott, N J; Bundgaard, M; Cserr, H F

    1985-01-01

    Cephalopod molluscs have complex brains and behaviour, yet little is known about the permeability of their blood-brain interface. The accompanying paper characterized the fluid compartments of the brain and presented evidence for restricted permeability of the blood-brain interface to albumin. The present paper investigates the permeability of the interface to small non-electrolytes. [14C]Polyethylene glycol (PEG, mol. wt. 4000), and [51Cr]EDTA (mol. wt. 342) were injected intravenously or intramuscularly, and their penetration into brain and muscle studied up to 48 h. Tracers equilibrated with muscle interstitial fluid (ISF) at relatively short times, but in brain ISF reached only 0.5-0.65 X their plasma concentration. This is qualitative evidence for the presence in brain of a barrier to these molecules and an efficient drainage mechanism for ISF. Quantitative treatment of the uptake data allows calculation of the permeability X surface area product (PS) and the permeability coefficient (P). For the brain PS and P are in the range 1-3 X 10(-4) ml g-1 min-1 and 1-3 X 10(-8) cm s-1 respectively, (PEG), and 3 X 10(-4) ml g-1 min-1 and 3-4 X 10(-8) cm s-1 respectively (Cr-EDTA). The P values are close to those reported for mammalian brain. Assuming that the lack of equilibration in brain is due to ISF flow, the rate of flow can be calculated. Values for vertical and optic lobe are approximately 0.2 microliter g-1 min-1, again close to those reported for mammalian brain. It is concluded that the tightness of the Sepia blood-brain barrier approaches that of mammals, and a flowing ISF system is present. An association between a tight barrier and higher central nervous system integrative function is suggested. The significance of these findings for the evolution of control of the brain microenvironment is discussed. Images Fig. 5 PMID:3935776

  6. Hyperosmolar opening of the blood-brain barrier in the energy-depleted rat brain. Part 1. Permeability studies

    SciTech Connect

    Greenwood, J.; Luthert, P.J.; Pratt, O.E.; Lantos, P.L.

    1988-02-01

    A simple saline perfusion system was used to investigate the effects of hyperosmolar solutions of arabinose and mannitol upon the permeability of the blood-brain barrier. The small, polar molecule (/sup 14/C)mannitol and the larger, visual marker Evans blue were used as indicators of barrier integrity in the perfused energy-depleted brain. One-minute perfusion of hyperosmolar solutions consistently opened the barrier suggesting that the mechanism of osmotic barrier opening is independent of energy-producing metabolism. The accumulation of radiolabel in the brain was expressed as the ratio of tissue to perfusate radioactivity (Rt/Rp) and, for cerebrum, this increased from a control value of 0.0022 +/- 0.0007 (mean +/- SEM; n = 4) to a value of 0.0124 +/- 0.0008 (n = 4) following 0.9 M arabinose and to 0.0495 +/- 0.0072 (n = 4) following 1.8 M arabinose. There was a significant reduction of water content of hyperosmolar perfused brains. These findings support the hypothesis that osmotic barrier opening is the result of the passive shrinkage of endothelial cells and the surrounding tissue.

  7. Effects of fractionated radiation on the brain vasculature in a murine model: Blood-brain barrier permeability, astrocyte proliferation, and ultrastructural changes

    SciTech Connect

    Yuan Hong; Gaber, M. Waleed . E-mail: wgaber@utmem.edu; Boyd, Kelli; Wilson, Christy M.; Kiani, Mohammad F.; Merchant, Thomas E.

    2006-11-01

    Purpose: Radiation therapy of CNS tumors damages the blood-brain barrier (BBB) and normal brain tissue. Our aims were to characterize the short- and long-term effects of fractionated radiotherapy (FRT) on cerebral microvasculature in mice and to investigate the mechanism of change in BBB permeability in mice. Methods and Materials: Intravital microscopy and a cranial window technique were used to measure BBB permeability to fluorescein isothiocyanate (FITC)-dextran and leukocyte endothelial interactions before and after cranial irradiation. Daily doses of 2 Gy were delivered 5 days/week (total, 40 Gy). We immunostained the molecules to detect the expression of glial fibrillary acidic protein and to demonstrate astrocyte activity in brain parenchyma. To relate the permeability changes to endothelial ultrastructural changes, we used electron microscopy. Results: Blood-brain barrier permeability did not increase significantly until 90 days after FRT, at which point it increased continuously until 180 days post-FRT. The number of adherent leukocytes did not increase during the study. The number of astrocytes in the cerebral cortex increased significantly; vesicular activity in endothelial cells increased beginning 90 days after irradiation, and most tight junctions stayed intact, although some were shorter and less dense at 120 and 180 days. Conclusions: The cellular and microvasculature response of the brain to FRT is mediated through astrogliosis and ultrastructural changes, accompanied by an increase in BBB permeability. The response to FRT is delayed as compared with single-dose irradiation treatment, and does not involve leukocyte adhesion. However, FRT induces an increase in the BBB permeability, as in the case of single-dose irradiation.

  8. Development of Blood-Brain Barrier Permeable Nitrocatechol-Based Catechol O-Methyltransferase Inhibitors with Reduced Potential for Hepatotoxicity.

    PubMed

    Silva, Tiago; Mohamed, Tarek; Shakeri, Arash; Rao, Praveen P N; Martínez-González, Loreto; Pérez, Daniel I; Martínez, Ana; Valente, Maria João; Garrido, Jorge; Uriarte, Eugenio; Serrão, Paula; Soares-da-Silva, Patrício; Remião, Fernando; Borges, Fernanda

    2016-08-25

    Recent efforts have been focused on the development of centrally active COMT inhibitors, which can be valuable assets for neurological disorders such as Parkinson's disease, due to the severe hepatotoxicity risk associated with tolcapone. New nitrocatechol COMT inhibitors based on naturally occurring caffeic acid and caffeic acid phenethyl ester were developed. All nitrocatechol derivatives displayed potent inhibition of peripheral and cerebral COMT within the nanomolar range. Druglike derivatives 13, 15, and 16 were predicted to cross the blood-brain barrier in vitro and were significantly less toxic than tolcapone and entacapone when incubated at 50 μM with rat primary hepatocytes. Moreover, their unique acidity and electrochemical properties decreased the chances of formation of reactive quinone-imines and, as such, the potential for hepatotoxicity. The binding mode of 16 confirmed that the major interactions with COMT were established via the nitrocatechol ring, allowing derivatization of the side chain for future lead optimization efforts. PMID:27463695

  9. In vivo two-photon imaging measuring the blood-brain barrier permeability during early postnatal brain development in rodent

    NASA Astrophysics Data System (ADS)

    Shi, Lingyan; Rodríguez-Contreras, Adrián.

    2016-03-01

    The blood-brain barrier (BBB) is a unique structure between the cerebral blood circulation and the delicate neural environment that is important in regulating the movement of molecules and ions involved in brain development and function. However, little is known about the physiological permeability of molecules and ions across the BBB during brain development. In this study we applied an innovative approach to examine the development of BBB properties quantitatively. Two-photon microscopy was employed to measure BBB permeability in real time in vivo. Vascular growth and specific interactions between astrocyte end feet and microvessels were studied by using a combination of IB4 histochemistry, immunohistochemistry, confocal microscopy and 3D analysis.

  10. Multidrug-resistance gene (P-glycoprotein) is expressed by endothelial cells at blood-brain barrier sites

    SciTech Connect

    Cordon-Cardo, C.; O'Brien, J.P.; Casals, D.; Biedler, J.L.; Melamed, M.R.; Bertino, J.R. ); Rittman-Grauer, L. )

    1989-01-01

    Endothelial cells of human capillary blood vessels at the blood-brain and other blood-tissue barrier sites express P-glycoprotein as detected by mouse monoclonal antibodies against the human multidrug-resistance gene product. This pattern of endothelial cell expression may indicate a physiological role for P-glycoprotein in regulating the entry of certain molecules into the central nervous system and other anatomic compartments, such as the testes. These tissues, which limit the access of systemic drugs, are known pharmacologic sanctuaries for metastatic cancer. P-glycoprotein expression in capillary endothelium of brain and testes and not other tissues (i.e., kidney and placenta) may in part explain this phenomenon and could have important implications in cancer chemotherapy.

  11. Magnetic resonance imaging of post-ischemic blood-brain barrier damage with PEGylated iron oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Liu, Dong-Fang; Qian, Cheng; An, Yan-Li; Chang, Di; Ju, Sheng-Hong; Teng, Gao-Jun

    2014-11-01

    Blood-brain barrier (BBB) damage during ischemia may induce devastating consequences like cerebral edema and hemorrhagic transformation. This study presents a novel strategy for dynamically imaging of BBB damage with PEGylated supermagnetic iron oxide nanoparticles (SPIONs) as contrast agents. The employment of SPIONs as contrast agents made it possible to dynamically image the BBB permeability alterations and ischemic lesions simultaneously with T2-weighted MRI, and the monitoring could last up to 24 h with a single administration of PEGylated SPIONs in vivo. The ability of the PEGylated SPIONs to highlight BBB damage by MRI was demonstrated by the colocalization of PEGylated SPIONs with Gd-DTPA after intravenous injection of SPION-PEG/Gd-DTPA into a mouse. The immunohistochemical staining also confirmed the leakage of SPION-PEG from cerebral vessels into parenchyma. This study provides a novel and convenient route for imaging BBB alteration in the experimental ischemic stroke model.

  12. Synthesis and biodistribution of neutral lipid-soluble Tc-99m complexes that cross the blood-brain barrier. [Monkeys

    SciTech Connect

    Kung, H.F.; Molnar, M.; Billings, J.; Wicks, R.; Blau, M.

    1984-03-01

    Three Tc-99m-labeled neutral 1,2-dithia-5,8-diazacyclodecane (BAT) chelates that are capable of crossing the blood-brain barrier (BBB) were prepared and evaluated. Biodistribution (i.v.) in rats showed a significant brain uptake (1-3%/whole brain) at 2 min. At 15 min the uptake dropped to about a tenth of the original level, indicating free passage in both directions across the BBB. Gamma camera images of a monkey confirmed the high initial brain uptake. This group of Tc-99m BAT compounds clearly exhibited in vivo stability and the ability to cross the BBB after an i.v. injection. Derivatives containing tertiary amine groups should have prolonged brain retention and might be suitable for SPECT studies of brain perfusion.

  13. Mechanisms and regulation of iron trafficking across the capillary endothelial cells of the blood-brain barrier

    PubMed Central

    McCarthy, Ryan C.; Kosman, Daniel J.

    2015-01-01

    The transcellular trafficking of iron from the blood into the brain interstitium depends on iron uptake proteins in the apical membrane of brain microvascular capillary endothelial cells and efflux proteins at the basolateral, abluminal membrane. In this review, we discuss the three mechanisms by which these cells take-up iron from the blood and the sole mechanism by which they efflux this iron into the abluminal space. We then focus on the regulation of this efflux pathway by exocrine factors that are released from neighboring astrocytes. Also discussed are the cytokines secreted by capillary cells that regulate the expression of these glial cell signals. Among the interstitial factors that regulate iron efflux into the brain is the Amyloid precursor protein (APP). The role of this amyliodogenic species in brain iron metabolism is discussed. Last, we speculate on the potential relationship between iron transport at the blood-brain barrier and neurological disorders associated with iron mismanagement. PMID:26236187

  14. Alterations in function and expression of ABC transporters at blood-brain barrier under diabetes and the clinical significances

    PubMed Central

    Liu, Li; Liu, Xiao-Dong

    2014-01-01

    Diabetes is a systematic metabolic disease, which often develops a number of well-recognized vascular complications including brain complications which may partly result from the dysfunction of blood-brain barrier (BBB). BBB is generally considered as a mechanism for protecting the brain from unwanted actions resulting from substances in the blood and maintaining brain homeostasis via monitoring the entry or efflux of compounds. ATP-binding cassette (ABC) family of transporters including P-glycoprotein (P-GP) and breast cancer-related protein (BCRP), widely expressed in the luminal membrane of the microvessel endothelium and in the apical membrane of the choroids plexus epithelium, play important roles in the function of BBB. However, these transporters are easily altered by some diseases. The present article was focused on the alteration in expression and function of both P-GP and BCRP at BBB by diabetes and the clinical significances. PMID:25540622

  15. Blood-brain barrier-permeable fluorone-labeled dieckols acting as neuronal ER stress signaling inhibitors.

    PubMed

    Kwak, Jong Hwan; Yang, Zhigang; Yoon, Byungkwon; He, Yanxia; Uhm, Soojin; Shin, Hyeon-Cheol; Lee, Bong Ho; Yoo, Yung Choon; Lee, Kyung Bok; Han, Seung-Yun; Kim, Jong Seung

    2015-08-01

    We studied the blood-brain barrier (BBB) permeability and intracellular localization of a fluorescein isothiocyanate (FITC)-labeled dieckol (1) and a rhodamine B-labeled dieckol (7), for exploring the possible therapeutic application of fluorone-labeled dieckols in neurodegenerative diseases. Both compounds (1 &7) were synthesized through a click reaction and were found to be localized in the endoplasmic reticulum (ER) of the two types of brain cell lines (SH-SY5Y and BV-2 cells) tested; they also reduced ER stress in the SH-SY5Y human neuroblastoma cells. In addition, 1 and 7 were shown to pass the BBB in rats upon intravenous administration. Altogether, our study demonstrates, for the first time, that targeted ER-stress reduction in brain cells can be achieved by introducing fluorone-dieckol conjugates into systemic circulation. Therefore, 1 and 7 provide a novel and promising ER-targeting therapeutic strategy for neurodegenerative diseases. PMID:25996411

  16. Mesenchymal Stem Cells Regulate Blood Brain Barrier Integrity in Traumatic Brain Injury Through Production of the Soluble Factor TIMP3

    PubMed Central

    Menge, Tyler; Zhao, Yuhai; Zhao, Jing; Wataha, Kathryn; Geber, Michael; Zhang, Jianhu; Letourneau, Phillip; Redell, John; Shen, Li; Wang, Jing; Peng, Zhalong; Xue, Hasen; Kozar, Rosemary; Cox, Charles S.; Khakoo, Aarif Y.; Holcomb, John B.; Dash, Pramod K.; Pati, Shibani

    2013-01-01

    Mesenchymal stem cells (MCSs) have been shown to have therapeutic potential in multiple disease states associated with vascular instability including traumatic brain injury (TBI). In the present study, Tissue Inhibitor of Matrix Metalloproteinase-3 (TIMP3) is identified as the soluble factor produced by MSCs that can recapitulate the beneficial effects of MSCs on endothelial function and blood brain barrier (BBB) compromise in TBI. Attenuation of TIMP3 expression in MSCs completely abrogates the effect of MSCs on BBB permeability and stability, while intravenous administration of rTIMP3 alone can inhibit BBB permeability in TBI. Our results demonstrate that MSCs increase circulating levels of soluble TIMP3, which inhibits VEGF-A induced breakdown of endothelial AJs in vitro and in vivo. These findings elucidate a clear molecular mechanism for the effects of MSCs on the BBB in TBI, and directly demonstrate a role for TIMP3 in regulation of BBB integrity. PMID:23175708

  17. Quantitative evaluation of the use of microbubbles with transcranial focused ultrasound on blood-brain-barrier disruption.

    PubMed

    Yang, Feng-Yi; Fu, Wen-Mei; Chen, Wen-Shiang; Yeh, Wei-Lan; Lin, Win-Li

    2008-04-01

    It has been shown that focused ultrasound (FUS) can disrupt the blood-brain barrier (BBB) noninvasively and reversibly at target locations when applied in the presence of ultrasound contrast agent (UCA). In this study, the dose-dependent effects of UCA on BBB disruption were investigated in the brains of 16 male Wistar rats sonicated by 1.0-MHz transcranial FUS, with the UCA present at four doses. The BBB disruption was evaluated quantitatively based on the extravasation of Evans blue (EB). The amount of EB extravasation in the brain increased with the quantity of UCA injected into the femoral vein prior to sonication. Moreover, the use of a suitable dose of UCA resulted in the BBB disruption being concentrated in the focal region instead of the entire brain. Our results indicate that injecting an appropriate quantity of UCA effectively increases and localizes the BBB disruption induced by transcranial FUS sonications. PMID:17910929

  18. In Vivo Bioluminescent Imaging of ATP-Binding Cassette Transporter-Mediated Efflux at the Blood-Brain Barrier.

    PubMed

    Bakhsheshian, Joshua; Wei, Bih-Rong; Hall, Matthew D; Simpson, R Mark; Gottesman, Michael M

    2016-01-01

    We provide a detailed protocol for imaging ATP-binding cassette subfamily G member 2 (ABCG2) function at the blood-brain barrier (BBB) of transgenic mice. D-Luciferin is specifically transported by ABCG2 found on the apical side of endothelial cells at the BBB. The luciferase-luciferin enzymatic reaction produces bioluminescence, which allows a direct measurement of ABCG2 function at the BBB. Therefore bioluminescence imaging (BLI) correlates with ABCG2 function at the BBB and this can be measured by administering luciferin in a mouse model that expresses luciferase in the brain parenchyma. BLI allows for a relatively low-cost alternative for studying transporter function in vivo compared to other strategies such as positron emission tomography. This method for imaging ABCG2 function at the BBB can be used to investigate pharmacokinetic inhibition of the transporter. PMID:27424909

  19. Focal MMP-2 and MMP-9 activity at the blood-brain barrier promotes chemokine-induced leukocyte migration.

    PubMed

    Song, Jian; Wu, Chuan; Korpos, Eva; Zhang, Xueli; Agrawal, Smriti M; Wang, Ying; Faber, Cornelius; Schäfers, Michael; Körner, Heinrich; Opdenakker, Ghislain; Hallmann, Rupert; Sorokin, Lydia

    2015-02-24

    Although chemokines are sufficient for chemotaxis of various cells, increasing evidence exists for their fine-tuning by selective proteolytic processing. Using a model of immune cell chemotaxis into the CNS (experimental autoimmune encephalomyelitis [EAE]) that permits precise localization of immigrating leukocytes at the blood-brain barrier, we show that, whereas chemokines are required for leukocyte migration into the CNS, additional MMP-2/9 activities specifically at the border of the CNS parenchyma strongly enhance this transmigration process. Cytokines derived from infiltrating leukocytes regulate MMP-2/9 activity at the parenchymal border, which in turn promotes astrocyte secretion of chemokines and differentially modulates the activity of different chemokines at the CNS border, thereby promoting leukocyte migration out of the cuff. Hence, cytokines, chemokines, and cytokine-induced MMP-2/9 activity specifically at the inflammatory border collectively act to accelerate leukocyte chemotaxis across the parenchymal border. PMID:25704809

  20. Viral sensing at the blood-brain barrier: new roles for innate immunity at the CNS vasculature.

    PubMed

    Daniels, B P; Klein, R S

    2015-04-01

    Neurotropic viral infections are a major source of disease worldwide and represent a growing burden to public health. While the central nervous system (CNS) is normally protected from viral infection by the blood-brain barrier (BBB), many viruses are able to cross the BBB and establish CNS infection through processes that largely remain poorly understood. A growing body of recent research has begun to shed light on the viral and host factors that modulate BBB function, contributing to both protective and pathological disease processes. Central to these studies have been the actions of host cytokines and chemokines, which have increasingly been shown to be key regulators of BBB physiology. This review summarizes recent advances in understanding how BBB function governs both viral pathogenesis and host immune responses during neurotropic viral infections. PMID:25670037

  1. Ultrasound-mediated blood-brain barrier disruption for targeted drug delivery in the central nervous system

    PubMed Central

    Aryal, Muna; Arvanitis, Costas D.; Alexander, Phillip M.; McDannold, Nathan

    2014-01-01

    The physiology of the vasculature in the central nervous system (CNS), which includes the blood-brain barrier (BBB) and other factors, complicates the delivery of most drugs to the brain. Different methods have been used to bypass the BBB, but they have limitations such as being invasive, non-targeted or requiring the formulation of new drugs. Focused ultrasound (FUS), when combined with circulating microbubbles, is a noninvasive method to locally and transiently disrupt the BBB at discrete targets. This review provides insight on the current status of this unique drug delivery technique, experience in preclinical models, and potential for clinical translation. If translated to humans, this method would offer a flexible means to target therapeutics to desired points or volumes in the brain, and enable the whole arsenal of drugs in the CNS that are currently prevented by the BBB. PMID:24462453

  2. Pilocarpine-induced convulsive activity is limited by multidrug transporters at the rodent blood-brain barrier.

    PubMed

    Römermann, K; Bankstahl, J P; Löscher, W; Bankstahl, M

    2015-05-01

    As a result of the growing availability of genetically engineered mouse lines, the pilocarpine post-status epilepticus (SE) model of temporal lobe epilepsy is increasingly used in mice. A discrepancy in pilocarpine sensitivity in FVB/N wild-type versus P-glycoprotein (PGP)-deficient mice precipitated the investigation of the interaction between pilocarpine and two major multidrug transporters at the blood-brain barrier. Doses of pilocarpine necessary for SE induction were determined in male and female wild-type and PGP-deficient mice. Brain and plasma concentrations were measured following low (30-50 mg⋅kg(-1) i.p.) and/or high (200 mg⋅kg(-1) i.p.) doses of pilocarpine in wild-type mice, and mice lacking PGP, breast cancer resistance protein (BCRP), or both transporters, as well as in rats with or without pretreatment with lithium chloride or tariquidar. Concentration equilibrium transport assays (CETA) were performed using cells overexpressing murine PGP or BCRP. Lower pilocarpine doses were necessary for SE induction in PGP-deficient mice. Brain-plasma ratios were higher in mice lacking PGP or PGP and BCRP, which was also observed after pretreatment with tariquidar in mice and in rats. Lithium chloride did not change brain penetration of pilocarpine. CETA confirmed transport of pilocarpine by PGP and BCRP. Pilocarpine is a substrate of PGP and BCRP at the rodent blood-brain barrier, which restricts its convulsive action. Future studies to reveal whether strain differences in pilocarpine sensitivity derive from differences in multidrug transporter expression levels are warranted. PMID:25755207

  3. Targeting blood-brain barrier sphingolipid signaling reduces basal P-glycoprotein activity and improves drug delivery to the brain

    PubMed Central

    Cannon, Ronald E.; Peart, John C.; Hawkins, Brian T.; Campos, Christopher R.; Miller, David S.

    2012-01-01

    P-glycoprotein, an ATP-driven drug efflux pump, is a major obstacle to the delivery of small-molecule drugs across the blood-brain barrier and into the CNS. Here we test a unique signaling-based strategy to overcome this obstacle. We used a confocal microscopy-based assay with isolated rat brain capillaries to map a signaling pathway that within minutes abolishes P-glycoprotein transport activity without altering transporter protein expression or tight junction permeability. This pathway encompasses elements of proinflammatory- (TNF-α) and sphingolipid-based signaling. Critical to this pathway was signaling through sphingosine-1-phosphate receptor 1 (S1PR1). In brain capillaries, S1P acted through S1PR1 to rapidly and reversibly reduce P-glycoprotein transport activity. Sphingosine reduced transport by a sphingosine kinase-dependent mechanism. Importantly, fingolimod (FTY720), a S1P analog recently approved for treatment of multiple sclerosis, also rapidly reduced P-glycoprotein activity; similar effects were found with the active, phosphorylated metabolite (FTY720P). We validated these findings in vivo using in situ brain perfusion in rats. Administration of S1P, FTY720, or FTY729P increased brain uptake of three radiolabeled P-glycoprotein substrates, 3H-verapamil (threefold increase), 3H-loperamide (fivefold increase), and 3H-paclitaxel (fivefold increase); blocking S1PR1 abolished this effect. Tight junctional permeability, measured as brain 14C-sucrose accumulation, was not altered. Therefore, targeting signaling through S1PR1 at the blood-brain barrier with the sphingolipid-based drugs, FTY720 or FTY720P, can rapidly and reversibly reduce basal P-glycoprotein activity and thus improve delivery of small-molecule therapeutics to the brain. PMID:22949658

  4. Carrier-Mediated Cocaine Transport at the Blood-Brain Barrier as a Putative Mechanism in Addiction Liability

    PubMed Central

    Chapy, Hélène; Smirnova, Maria; André, Pascal; Schlatter, Joël; Chiadmi, Fouad; Couraud, Pierre-Olivier; Scherrmann, Jean-Michel; Declèves, Xavier

    2015-01-01

    Background: The rate of entry of cocaine into the brain is a critical factor that influences neuronal plasticity and the development of cocaine addiction. Until now, passive diffusion has been considered the unique mechanism known by which cocaine crosses the blood-brain barrier. Methods: We reassessed mechanisms of transport of cocaine at the blood-brain barrier using a human cerebral capillary endothelial cell line (hCMEC/D3) and in situ mouse carotid perfusion. Results: Both in vivo and in vitro cocaine transport studies demonstrated the coexistence of a carrier-mediated process with passive diffusion. At pharmacological exposure level, passive diffusion of cocaine accounted for only 22.5% of the total cocaine influx in mice and 5.9% in hCMEC/D3 cells, whereas the carrier-mediated influx rate was 3.4 times greater than its passive diffusion rate in vivo. The functional identification of this carrier-mediated transport demonstrated the involvement of a proton antiporter that shared the properties of the previously characterized clonidine and nicotine transporter. The functionnal characterization suggests that the solute carrier (SLC) transporters Oct (Slc22a1-3), Mate (Slc47a1) and Octn (Slc22a4-5) are not involved in the cocaine transport in vivo and in vitro. Diphenhydramine, heroin, tramadol, cocaethylene, and norcocaine all strongly inhibited cocaine transport, unlike benzoylecgonine. Trans-stimulation studies indicated that diphenhydramine, nicotine, 3,4-methylenedioxyamphetamine (ecstasy) and the cathinone compound 3,4-methylenedioxypyrovalerone (MDPV) were also substrates of the cocaine transporter. Conclusions: Cocaine transport at the BBB involves a proton-antiporter flux that is quantitatively much more important than its passive diffusion. The molecular identification and characterization of this transporter will provide new tools to understand its role in addictive mechanisms. PMID:25539501

  5. P-glycoprotein activity in the blood-brain barrier is affected by virus-induced neuroinflammation and antipsychotic treatment.

    PubMed

    Doorduin, Janine; de Vries, Erik F J; Dierckx, Rudi A; Klein, Hans C

    2014-10-01

    A large percentage of schizophrenic patients respond poorly to antipsychotic treatment. This could be explained by inefficient drug transport across the blood-brain barrier due to P-glycoprotein mediated efflux. P-glycoprotein activity and expression in the blood-brain barrier can be affected by inflammation and pharmacotherapy. We therefore investigated the effect of herpes simplex virus type-1 (HSV-1) induced neuroinflammation and antipsychotic treatment on P-glycoprotein activity. Rats were inoculated with HSV-1 or PBS (control) on day 0 and treated with saline, clozapine or risperidone from day 0 up until day 4 post-inoculation. Positron emission tomography with the P-glycoprotein substrate [11C]verapamil was used to assess P-glycoprotein activity at day 6 post-inoculation. Disease symptoms in HSV-1 inoculated rats increased over time and were not significantly affected by treatment. The volume of distribution (VT) of [11C]verapamil was significantly lower (10-22%) in HSV-1 inoculated rats than in control rats. In addition, antipsychotic treatment significantly affected the VT of [11C]verapamil in all brain regions, although this effect was drug dependent. In fact, VT of [11C]verapamil was significantly increased (22-39%) in risperidone treated rats in most brain regions when compared to clozapine treated rats and in midbrain when compared to saline treated rats. No interaction between HSV-1 inoculation and antipsychotic treatment on VT of [11C]verapamil was found. In this study we demonstrated that HSV-1 induced neuroinflammation increased and risperidone treatment decreased P-glycoprotein activity. This finding is of importance for the understanding of treatment resistance in schizophrenia, and warrants further investigation of the underlying mechanism and the importance in clinical practice. PMID:24973705

  6. Blood-Brain Barrier Disruption and Oxidative Stress in Guinea Pig after Systemic Exposure to Modified Cell-Free Hemoglobin

    PubMed Central

    Butt, Omer I.; Buehler, Paul W.; D'Agnillo, Felice

    2011-01-01

    Systemic exposure to cell-free hemoglobin (Hb) or its breakdown products after hemolysis or with the use of Hb-based oxygen therapeutics may alter the function and integrity of the blood-brain barrier. Using a guinea pig exchange transfusion model, we investigated the effect of a polymerized cell-free Hb (HbG) on the expression of endothelial tight junction proteins (zonula occludens 1, claudin-5, and occludin), astrocyte activation, IgG extravasation, heme oxygenase (HO), iron deposition, oxidative end products (4-hydroxynonenal adducts and 8-hydroxydeoxyguanosine), and apoptosis (cleaved caspase 3). Reduced zonula occludens 1 expression was observed after HbG transfusion as evidenced by Western blot and confocal microscopy. Claudin-5 distribution was altered in small- to medium-sized vessels. However, total expression of claudin-5 and occludin remained unchanged except for a notable increase in occludin 72 hours after HbG transfusion. HbG-transfused animals also showed increased astrocytic glial fibrillary acidic protein expression and IgG extravasation after 72 hours. Increased HO activity and HO-1 expression with prominent enhancement of HO-1 immunoreactivity in CD163-expressing perivascular cells and infiltrating monocytes/macrophages were also observed. Consistent with oxidative stress, HbG increased iron deposition, 4-hydroxynonenal and 8-hydroxydeoxyguanosine immunoreactivity, and cleaved caspase-3 expression. Systemic exposure to an extracellular Hb triggers blood-brain barrier disruption and oxidative stress, which may have important implications for the use of Hb-based therapeutics and may provide indirect insight on the central nervous system vasculopathies associated with excessive hemolysis. PMID:21356382

  7. Magnetic Resonance Imaging of Blood Brain/Nerve Barrier Dysfunction and Leukocyte Infiltration: Closely Related or Discordant?

    PubMed Central

    Weise, Gesa; Stoll, Guido

    2012-01-01

    Unlike other organs the nervous system is secluded from the rest of the organism by the blood brain barrier (BBB) or blood nerve barrier (BNB) preventing passive influx of fluids from the circulation. Similarly, leukocyte entry to the nervous system is tightly controlled. Breakdown of these barriers and cellular inflammation are hallmarks of inflammatory as well as ischemic neurological diseases and thus represent potential therapeutic targets. The spatiotemporal relationship between BBB/BNB disruption and leukocyte infiltration has been a matter of debate. We here review contrast-enhanced magnetic resonance imaging (MRI) as a non-invasive tool to depict barrier dysfunction and its relation to macrophage infiltration in the central and peripheral nervous system under pathological conditions. Novel experimental contrast agents like Gadofluorine M (Gf) allow more sensitive assessment of BBB dysfunction than conventional Gadolinium (Gd)-DTPA enhanced MRI. In addition, Gf facilitates visualization of functional and transient alterations of the BBB remote from lesions. Cellular contrast agents such as superparamagnetic iron oxide particles (SPIO) and perfluorocarbons enable assessment of leukocyte (mainly macrophage) infiltration by MR technology. Combined use of these MR contrast agents disclosed that leukocytes can enter the nervous system independent from a disturbance of the BBB, and vice versa, a dysfunctional BBB/BNB by itself is not sufficient to attract inflammatory cells from the circulation. We will illustrate these basic imaging findings in animal models of multiple sclerosis, cerebral ischemia, and traumatic nerve injury and review corresponding findings in patients. PMID:23267343

  8. Cilostazol reduces blood brain barrier dysfunction, white matter lesion formation and motor deficits following chronic cerebral hypoperfusion.

    PubMed

    Edrissi, Hamidreza; Schock, Sarah C; Cadonic, Robert; Hakim, Antoine M; Thompson, Charlie S

    2016-09-01

    Cerebral small vessel disease (CSVD) is a pathological process leading to lacunar infarcts, leukoaraiosis and cerebral microbleeds. Dysfunction of the blood brain barrier (BBB) has been proposed as a mechanism in the progression cerebral small vessel disease. A rodent model commonly used to study some aspects of CSVD is bilateral common carotid artery occlusion (BCCAO) in the rat. In the present study it was determined that gait impairment, as determined by a tapered beam test, and BBB permeability increased following BCCAO. Cilostazol, a type III phosphodiesterase inhibitor, has been shown to have anti-apoptotic effects and prevent white matter vacuolation and rarefaction induced by BCCAO in rats. In this study the protective effect of cilostazol administration on the increase BBB permeability following BCCAO was determined as well as the effect on plasma levels of circulating microparticles (MPs), cerebral white matter rarefaction, glial activation and gait disturbance. The effect of cilostazol on in vitro endothelial barriers was also evaluated. Cilostazol treatment improved BBB permeability and reduced gait disturbance, visual impairment and microglial activation in optic tract following BCCAO in vivo. It also reduced the degree of cell death and the reduction in trans-endothelial electrical resistance (TEER) in artificial endothelial barriers in vitro induced by MP treatment of in vitro barriers. PMID:27350079

  9. Prolonged Morphine Exposure Induces Increased Firm Adhesion in an in Vitro Model of the Blood-Brain Barrier.

    PubMed

    Strazza, Marianne; Pirrone, Vanessa; Wigdahl, Brian; Dampier, Will; Lin, Wei; Feng, Rui; Maubert, Monique E; Weksler, Babette; Romero, Ignacio A; Couraud, Pierre-Olivier; Nonnemacher, Michael R

    2016-01-01

    The blood-brain barrier (BBB) has been defined as a critically important protective barrier that is involved in providing essential biologic, physiologic, and immunologic separation between the central nervous system (CNS) and the periphery. Insults to the BBB can cause overall barrier damage or deregulation of the careful homeostasis maintained between the periphery and the CNS. These insults can, therefore, yield numerous phenotypes including increased overall permeability, interendothelial gap formation, alterations in cytokine and chemokine secretion, and accelerated cellular passage. The current studies expose the human brain microvascular endothelial cell line, hCMEC/D3, to prolonged morphine exposure and aim to uncover the mechanisms underlying alterations in barrier function in vitro. These studies show alterations in the mRNA and protein levels of the cellular adhesion molecules (CAMs) intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and activated leukocyte cell adhesion molecule that correlate with an increased firm adhesion of the CD3⁺ subpopulation of peripheral blood mononuclear cells (PBMCs). Overall, these studies suggest that prolonged morphine exposure may result in increased cell migration into the CNS, which may accelerate pathological processes in many diseases that involve the BBB. PMID:27294916

  10. Improved survival in rats with glioma using MRI-guided focused ultrasound and microbubbles to disrupt the blood-brain barrier and deliver Doxil

    NASA Astrophysics Data System (ADS)

    Aryal, Muna; Zhi Zhang, Yong; Vykhodtseva, Natalia; Park, Juyoung; Power, Chanikarn; McDannold, Nathan

    2012-02-01

    Blood-brain-barrier (BBB) limits the transportation of most neuropeptides, proteins (enzymes, antibodies), chemotherapeutic agents, and genes that have therapeutic potential for the treatment of brain diseases. Different methods have been used to overcome this limitation, but they are invasive, non-targeted, or require the development of new drugs. We have developed a method that uses MRI-guided focused ultrasound (FUS) combined with circulating microbubbles to temporarily open BBB in and around brain tumors to deliver chemotherapy agents. Here, we tested whether this noninvasive technique could enhance the effectiveness of a chemotherapy agent (Doxil). Using 690 kHz FUS transducer and microbubble (Definity), we induced BBB disruption in intracranially-implanted 9L glioma tumors in rat's brain in three weekly sessions. Animals who received BBB disruption and Doxil had a median survival time of 34.5 days, which was significantly longer than that found in control animals which is 16, 18.5, 21 days who received no treatment, BBB disruption only and Doxil only respectively This work demonstrates that FUS technique has promise in overcoming barriers to drug delivery, which are particularly stark in the brain due to the BBB.

  11. In vitro models of the blood-brain barrier: An overview of commonly used brain endothelial cell culture models and guidelines for their use.

    PubMed

    Helms, Hans C; Abbott, N Joan; Burek, Malgorzata; Cecchelli, Romeo; Couraud, Pierre-Olivier; Deli, Maria A; Förster, Carola; Galla, Hans J; Romero, Ignacio A; Shusta, Eric V; Stebbins, Matthew J; Vandenhaute, Elodie; Weksler, Babette; Brodin, Birger

    2016-05-01

    The endothelial cells lining the brain capillaries separate the blood from the brain parenchyma. The endothelial monolayer of the brain capillaries serves both as a crucial interface for exchange of nutrients, gases, and metabolites between blood and brain, and as a barrier for neurotoxic components of plasma and xenobiotics. This "blood-brain barrier" function is a major hindrance for drug uptake into the brain parenchyma. Cell culture models, based on either primary cells or immortalized brain endothelial cell lines, have been developed, in order to facilitate in vitro studies of drug transport to the brain and studies of endothelial cell biology and pathophysiology. In this review, we aim to give an overview of established in vitro blood-brain barrier models with a focus on their validation regarding a set of well-established blood-brain barrier characteristics. As an ideal cell culture model of the blood-brain barrier is yet to be developed, we also aim to give an overview of the advantages and drawbacks of the different models described. PMID:26868179

  12. Intra-arterial administration of carboplatin and the blood brain barrier permeabilizing agent, RMP-7: a toxicologic evaluation in swine.

    PubMed

    Riley, M G; Kim, N N; Watson, V E; Gobin, Y P; LeBel, C P; Black, K L; Bartus, R T

    1998-01-01

    RMP-7 is a bradykinin B2 receptor agonist shown to permeabilize the blood-brain barrier, especially that associated with brain tumors, when administered via both intracarotid and intravenous routes. Both routes of administration are currently being tested in human trials in combination with the chemotherapeutic agent carboplatin as therapy for gliomas. As an essential prerequisite to the initial intracarotid clinical trials, the potential neurotoxicity of intra-arterial administration of RMP-7 (at a high or low dose), alone and in combination with carboplatin, was assessed in anesthetized Red Duroc swine. Five treatment groups were evaluated with each pig receiving a series of alternating, intra-arterial infusions of RMP-7 (or saline) followed by carboplatin (or saline), as follows: (1) vehicle control: saline/saline; (2) carboplatin only control: saline/carboplatin (50 mg total); (3) RMP-7 only control: RMP-7 (750 ng/kg)/saline; (4) low dose combination: RMP-7 (75 ng/kg)/carboplatin (50 mg total); and (5) high dose combination: RMP-7 (750 ng/kg)/carboplatin (50 mg total). For each subject, one of the alternating dosing sequences (above) was repeated four times during a single dosing session which lasted approximately 40 minutes. Assessments during the in-life phase of the study in the pre- and post-treatment periods consisted of heart rate, arterial blood pressure (systolic, diastolic, and mean), blood gases, body weight, general clinical observations (including evaluation for neurological deficit) and clinical pathology (including a comprehensive battery of standard blood coagulation, hematological and serum chemistry tests). In addition, during the time of treatment, heart rate and arterial blood pressure were monitored. The animals were terminated two weeks after dosing and the brain and rete mirabile (distal to site of infusion) were evaluated for gross and histopathological abnormalities. The histopathology analysis included a reader-blinded analysis using

  13. Influence of P-glycoprotein inhibition on the distribution of the tricyclic antidepressant nortriptyline over the blood-brain barrier.

    PubMed

    Ejsing, Thomas B; Linnet, Kristian

    2005-03-01

    The distribution of the antidepressant drug nortriptyline (NT) and its main metabolite E-10-hydroxy-nortriptyline (E-10-OH-NT) across the blood-brain barrier was considered in relation to inhibition of the multidrug transporter P-glycoprotein (P-gp). Rats received NT in doses of 25 mg/kg orally, 10 mg/kg i.p. or 25 mg/kg i.p. Half the rats were treated with the P-glycoprotein inhibitor cyclosporine A (CsA) (200 mg/kg) 2 h prior to NT administration, and the other half served as a control group. NT and the metabolite were extracted from brain and serum by liquid-liquid extraction and analysed by HPLC with UV-detection. The brain to serum ratio of NT was increased in the CsA treated groups (22.3-26.8) compared with the control groups (16.5-22.7), the difference being statistically significant in two of the three experiments (p<0.05). Increased brain-serum ratios were also found for E-10-OH-NT, but the differences were not statistically significant. These results suggest that inhibition of P-gp by CsA increases the accumulation of NT in the brain. Administration of the antipsychotic drug risperidone (0.5 mg/kg s.c.), which is a P-gp substrate, instead of CsA did not exert any measurable influence on the blood-brain ratio of NT concentrations. In conclusion, the results show that drug-drug interaction at P-gp may influence the intracerebral NT concentration, but apparently, a major inhibition of P-gp is necessary to attain a measurable effect. PMID:15624117

  14. Multiple sessions of liposomal doxorubicin delivery via focused ultrasound mediated blood-brain barrier disruption: a safety study

    PubMed Central

    Aryal, Muna; Vykhodtseva, Natalia; Zhang, Yong-Zhi; McDannold, Nathan

    2015-01-01

    Transcranial MRI-guided focused ultrasound is a rapidly advancing method for delivering therapeutic and imaging agents to the brain. It has the ability to facilitate the passage of therapeutics from the vasculature to the brain parenchyma, which is normally protected by the blood-brain barrier (BBB). The method’s main advantages are that it is both targeted and noninvasive, and that it can be easily repeated. Studies have shown that liposomal doxorubicin (Lipo-DOX), a chemotherapy agent with promise for tumors in the central nervous system, can be delivered into the brain across BBB. However, prior studies have suggested that doxorubicin can be significantly neurotoxic, even at small concentrations. Here, we studied whether multiple sessions of Lipo-DOX administered after FUS-induced BBB disruption (FUS-BBBD) induces severe adverse events in the normal brain tissues. First, we used fluorometry to measure the doxorubicin concentrations in the brain after FUS-BBBD to ensure that a clinically relevant doxorubicin concentration was achieved in the brain. Next, we performed three weekly sessions with FUS-BBBD ± Lipo-DOX administration. Five to twelve targets were sonicated each week, following a schedule described previously in a survival study in glioma-bearing rats (Aryal et al., 2013). Five rats received three weekly sessions where i.v. injected Lipo-DOX was combined with FUS-BBBD; an additional four rats received FUS-BBBD only. Animals were euthanized 70 days from the first session and brains were examined in histology. We found that clinically-relevant concentrations of doxorubicin (4.8 ± 0.5 µg/g) were delivered to the brain with the sonication parameters (0.69 MHz; 0.55–0.81 MPa; 10 ms bursts; 1 Hz PRF; 60s duration), microbubble concentration (Definity, 10 µl/kg), and the administered Lipo-DOX dose (5.67 mg/kg) used. The resulting concentration of Lipo-DOX was reduced by 32% when it was injected 10 minutes after the last sonication compared to cases

  15. Pharmacodynamic and Therapeutic Investigation of Focused Ultrasound-Induced Blood-Brain Barrier Opening for Enhanced Temozolomide Delivery in Glioma Treatment

    PubMed Central

    Liu, Hao-Li; Huang, Chiung-Yin; Chen, Ju-Yu; Wang, Hay-Yan Jack; Chen, Pin-Yuan; Wei, Kuo-Chen

    2014-01-01

    Focused ultrasound (FUS) exposure with the presence of microbubbles has been shown to transiently open the blood-brain barrier (BBB), and thus has potential to enhance the delivery of various kinds of therapeutic agents into brain tumors. The purpose of this study was to assess the preclinical therapeutic efficacy of FUS-BBB opening for enhanced temozolomide (TMZ) delivery in glioma treatment. FUS exposure with microbubbles was delivered to open the BBB of nude mice that were either normal or implanted with U87 human glioma cells. Different TMZ dose regimens were tested, ranging from 2.5 to 25 mg/kg. Plasma and brain samples were obtained at different time-points ranging from 0.5 to 4 hours, and the TMZ concentration within samples was quantitated via a developed LC-MS/MS procedure. Tumor progression was followed with T2-MRI, and animal survival and brain tissue histology were conducted. Results demonstrated that FUS-BBB opening caused the local TMZ accumulation in the brain to increase from 6.98 to 19 ng/mg. TMZ degradation time in the tumor core was found to increase from 1.02 to 1.56 hours. Improved tumor progression and animal survival were found at different TMZ doses (up to 15% and 30%, respectively). In conclusion, this study provides preclinical evidence that FUS-BBB opening increases the local concentration of TMZ to improve the control of tumor progression and animal survival, suggesting the potential for clinical application to improve current brain tumor treatment. PMID:25490097

  16. Traumatic brain injury opens blood-brain barrier to stealth liposomes via an enhanced permeability and retention (EPR)-like effect.

    PubMed

    Boyd, Ben J; Galle, Adam; Daglas, Maria; Rosenfeld, Jeffrey V; Medcalf, Robert

    2015-01-01

    The opening of the tight junctions in the blood-brain barrier (BBB) following traumatic brain injury (TBI) is hypothesized to be sufficient to enable accumulation of large drug carriers, such as stealth liposomes, in a similar manner to the extravasation seen in tumor tissue via the enhanced permeability and retention (EPR) effect. The controlled cortical impact model of TBI was used to evaluate liposome accumulation in mice. Dual-radiolabeled PEGylated liposomes were administered either immediately after induction of TBI or at increasing times post-TBI to mimic the likely clinical scenario. The accumulation of radiolabel in the brain tissue ipsilateral and contralateral to the site of trauma, as well as in other organs, was evaluated. Selective influx of liposomes occurred at 0-8 h after injury, while the barrier closed between 8 and 24 hr after injury, consistent with reports on albumin infiltration. Significantly enhanced accumulation of liposomes occurred in mice subjected to TBI compared to anaesthetized controls, and accumulation was greater in the injured versus the contralateral side of the brain. Thus, stealth liposomes show potential to enhance drug delivery to the site of brain injury with a wide range of encapsulated therapeutic candidates. PMID:26079716

  17. Stabilising cubosomes with Tween 80 as a step towards targeting lipid nanocarriers to the blood-brain barrier.

    PubMed

    Azhari, Hanisah; Strauss, Mike; Hook, Sarah; Boyd, Ben J; Rizwan, Shakila B

    2016-07-01

    Coating nanoparticles with the surfactant Tween 80 have been previously shown to enhance drug delivery across the blood-brain barrier (BBB). The aim of this study was to investigate whether Tween 80 could be used to stabilise phytantriol-based cubosomes thereby enabling potential application in delivering macromolecular therapeutics to the brain. Cubosome particles with their large internal and external surface area by virtue of their nanostructure are ideal for delivery of macromolecules. Phase behaviour studies were conducted using a combination of optical microscopy and small-angle X-ray scattering (SAXS) and the addition of Tween 80 to mixtures of phytantriol and water resulted in a rich array of lyotropic mesophases. In particular, a large cubic phase region and a two-phase region of readily dispersed cubosomes is observed. Cubosomes with different concentrations of Tween 80 and phytantriol as the liquid crystal forming lipid were prepared using the solvent precursor method and their physical properties were investigated. A combination of dynamic light scattering, cryogenic electron tomography and SAXS shows formation of well-defined cubosomes with a narrow size distribution and the Im3m cubic structure. Collectively, the results confirm that Tween 80 can effectively stabilize phytantriol cubosomes, opening the possibility for future application in drug delivery across the BBB. Moreover, well-defined, homogenous cubosome formulations prepared using the mild solvent precursor dilution method has significant implications for large-scale production of cubosomes, which currently is a major barrier to the application of cubosomes in the clinic. PMID:27163239

  18. Adverse effects of antipsychotics on micro-vascular endothelial cells of the human blood-brain barrier.

    PubMed

    Elmorsy, Ekramy; Elzalabany, Laila M; Elsheikha, Hany M; Smith, Paul A

    2014-10-01

    Although the mechanisms of action of antipsychotics (APs) on neuronal function are well understood, very little is known about their effects on cells of the blood-brain barrier (BBB); one function of which is to limit the access of these amphiphilic compounds to the central nervous system. To address this question we have investigated the cytological and functional effects of four APs: chlorpromazine (CLP), haloperidol (HAL), risperidone (RIS) and clozapine (CLZ), at concentrations typical of high therapeutic dosage on a human brain microvascular endothelial cell (HBMEC) model of the BBB. At ~10 µM all four APs impaired the ability of HBMECs to reduce MTT which was followed by decreased Trypan blue exclusion and increased Lactate dehydrogenase release. These effects were associated with oxidative stress which was partly reversed by incubation in 10mM glutathione. At their EC50 concentrations for MTT reduction, all four APs disrupted cellular ultrastructure and morphology. HAL, CPZ and CLZ increased Caspase -3, -8 and -9 activity, chromatin condensation and fragmentation, data indicative of apoptosis. These events were associated with decreased transcytosis of Evans blue and increased transendothelial potential difference and electrical resistance of this BBB model. These findings suggest that at high therapeutic concentrations, CPZ and CLZ are likely to incur cytoxic effects and apoptosis of BBB endothelia with an impairment of barrier functionality. Such events may underlie the aetiology of neuroleptic associated cerebral oedema and neuroleptic malignant syndrome. PMID:25139421

  19. Rapid remodeling of tight junctions during paracellular diapedesis in a human model of the blood-brain barrier.

    PubMed

    Winger, Ryan C; Koblinski, Jennifer E; Kanda, Takashi; Ransohoff, Richard M; Muller, William A

    2014-09-01

    Leukocyte transendothelial migration (TEM; diapedesis) is a critical event in immune surveillance and inflammation. Most TEM occurs at endothelial cell borders (paracellular). However, there is indirect evidence to suggest that, at the tight junctions of the blood-brain barrier (BBB), leukocytes migrate directly through the endothelial cell body (transcellular). Why leukocytes migrate through the endothelial cell body rather than the cell borders is unknown. To test the hypothesis that the tightness of endothelial cell junctions influences the pathway of diapedesis, we developed an in vitro model of the BBB that possessed 10-fold higher electrical resistance than standard culture conditions and strongly expressed the BBB tight junction proteins claudin-5 and claudin-3. We found that paracellular TEM was still the predominant pathway (≥98%) and TEM was dependent on PECAM-1 and CD99. We show that endothelial tight junctions expressing claudin-5 are dynamic and undergo rapid remodeling during TEM. Membrane from the endothelial lateral border recycling compartment is mobilized to the exact site of tight junction remodeling. This preserves the endothelial barrier by sealing the intercellular gaps with membrane and engaging the migrating leukocyte with unligated adhesion molecules (PECAM-1 and CD99) as it crosses the cell border. These findings provide new insights into leukocyte-endothelial interactions at the BBB and suggest that tight junctions are more dynamic than previously appreciated. PMID:25063869

  20. The UDP-glucuronosyltransferases of the blood-brain barrier: their role in drug metabolism and detoxication

    PubMed Central

    Ouzzine, Mohamed; Gulberti, Sandrine; Ramalanjaona, Nick; Magdalou, Jacques; Fournel-Gigleux, Sylvie

    2014-01-01

    UDP-glucuronosyltransferases (UGTs) form a multigenic family of membrane-bound enzymes expressed in various tissues, including brain. They catalyze the formation of β-D-glucuronides from structurally unrelated substances (drugs, other xenobiotics, as well as endogenous compounds) by the linkage of glucuronic acid from the high energy donor, UDP-α-D-glucuronic acid. In brain, UGTs actively participate to the overall protection of the tissue against the intrusion of potentially harmful lipophilic substances that are metabolized as hydrophilic glucuronides. These metabolites are generally inactive, except for important pharmacologically glucuronides such as morphine-6-glucuronide. UGTs are mainly expressed in endothelial cells and astrocytes of the blood brain barrier (BBB). They are also associated to brain interfaces devoid of BBB, such as circumventricular organ, pineal gland, pituitary gland and neuro-olfactory tissues. Beside their key-role as a detoxication barrier, UGTs play a role in the steady-state of endogenous compounds, like steroids or dopamine (DA) that participate to the function of the brain. UGT isoforms of family 1A, 2A, 2B and 3A are expressed in brain tissues to various levels and are known to present distinct but overlapping substrate specificity. The importance of these enzyme species with regard to the formation of toxic, pharmacologically or physiologically relevant glucuronides in the brain will be discussed. PMID:25389387

  1. Maternal Obesity in the Mouse Compromises the Blood-Brain Barrier in the Arcuate Nucleus of Offspring.

    PubMed

    Kim, Dong Won; Glendining, Kelly A; Grattan, David R; Jasoni, Christine L

    2016-06-01

    The arcuate nucleus (ARC) regulates body weight in response to blood-borne signals of energy balance. Blood-brain barrier (BBB) permeability in the ARC is determined by capillary endothelial cells (ECs) and tanycytes. Tight junctions between ECs limit paracellular entry of blood-borne molecules into the brain, whereas EC transporters and fenestrations regulate transcellular entry. Tanycytes appear to form a barrier that prevents free diffusion of blood-borne molecules. Here we tested the hypothesis that gestation in an obese mother alters BBB permeability in the ARC of offspring. A maternal high-fat diet model was used to generate offspring from normal-weight (control) and obese dams (OffOb). Evans Blue diffusion into the ARC was higher in OffOb compared with controls, indicating that ARC BBB permeability was altered. Vessels investing the ARC in OffOb had more fenestrations than controls, although the total number of vessels was not changed. A reduced number of tanycytic processes in the ARC of OffOb was also observed. The putative transporters, Lrp1 and dysferlin, were up-regulated and tight junction components were differentially expressed in OffOb compared with controls. These data suggest that maternal obesity during pregnancy can compromise BBB formation in the fetus, leading to altered BBB function in the ARC after birth. PMID:27054554

  2. Statins Inhibit Fibrillary β-Amyloid Induced Inflammation in a Model of the Human Blood Brain Barrier

    PubMed Central

    Griffin, Jarred M.; Kho, Dan; Graham, E. Scott; Nicholson, Louise F. B.; O’Carroll, Simon J.

    2016-01-01

    Background Astrocytes and cerebral endothelial cells are important components of the blood-brain barrier (BBB). Disruption to this barrier through inflammation is a major contributor to Alzheimer’s disease (AD) pathology. The amyloid beta (Aβ) protein is known to exist in several forms and is a key modulator of AD that is known to cause inflammation and changes to BBB function. While one of these forms, fibrillary Aβ (fAβ), is known to cause endothelial cell death at the BBB, no studies have looked specifically at its role on inflammation in a model of the human BBB. Aims To determine if fAβ is inflammatory to the human BBB. As statins have been shown to be anti-inflammatory and protective in AD, we also tested if these could inhibit the inflammatory effect of fAβ. Methods Using cultured cerebral endothelial cells and astrocytes we determined changes in cytokine release, cell toxicity and barrier function in response to fibrillary β-amyloid1–42 (fAβ1–42) alone and in combination with statins. Results fAβ1–42 induced inflammatory cytokine release from endothelial cells in the absence of cell toxicity. It also induced astrocyte cytokine release and cell death and caused a loss of barrier integrity. Statin treatment inhibited all of these effects. Conclusions We conclude that fAβ1–42 has both inflammatory and cytotoxic effects on the BBB and the protective effect of statins in AD may in part be through inhibiting these effects. PMID:27309956

  3. Communication from the periphery to the hypothalamus through the blood-brain barrier: An in vitro platform.

    PubMed

    Martins, João Pedro; Alves, Cecília Juliana; Neto, Estrela; Lamghari, Meriem

    2016-02-29

    One of the major routes of communication from the peripheral systems to the hypothalamus, the core structure of body homeostasis, is the humoral transmission through the blood-brain barrier (BBB). The BBB cultures are the in vitro model of choice to depict the mechanisms behind blood-brain interplay. Still, this strategy excludes the integration of the brain tissue response and, therefore, the resulting output might be limited. In this study, two in vitro assays were established: BBB coculture model and hypothalamic organotypic cultures. The combination of these two assays was used as a platform to address the two critical steps in the humoral transmission through the BBB to the brain: blood-BBB/BBB-brain. The in vitro model of the BBB was performed according to a coculture system using a brain microvascular endothelial cell line (bEnd.3) and primary astrocytes. The expression of junctional molecules as claudin-5, ZO-1, occludin and VE-cadherin was observed in the bEnd.3 cell-cell contact, confirming the BBB phenotype of these endothelial cells. Moreover, the transendothelial electrical resistance (TEER) values (71.1±9.4Ω× cm(2)) and the permeability coefficients (Pe) obtained in the transendothelial flux test (3.3±0.11×10(-6)cm/sec) support high integrity of the established barrier. The hypothalamic organotypic cultures were prepared from 8-days-old C57Bl/6 mice brains, based on the air-medium interface culture method. High cell viability (82±9.6%) and a dense neuronal network were achieved. The stimulation with dexamethasone resulted in an increased neuropeptide (NPY) expression, confirming the responsiveness of the neuronal system of these organotypic cultures. After optimization and characterization of each assay, the functionality of the platform was validated through the evaluation of the hypothalamic response to deep wound encompassing skin and muscle in mice. Results allowed to identify increased NPY activity in hypothalamic slices in response to

  4. Astrocytic modulation of blood brain barrier: perspectives on Parkinson’s disease

    PubMed Central

    Cabezas, Ricardo; Ávila, Marcos; Gonzalez, Janneth; El-Bachá, Ramon Santos; Báez, Eliana; García-Segura, Luis Miguel; Jurado Coronel, Juan Camilo; Capani, Francisco; Cardona-Gomez, Gloria Patricia; Barreto, George E.

    2014-01-01

    The blood–brain barrier (BBB) is a tightly regulated interface in the Central Nervous System (CNS) that regulates the exchange of molecules in and out from the brain thus maintaining the CNS homeostasis. It is mainly composed of endothelial cells (ECs), pericytes and astrocytes that create a neurovascular unit (NVU) with the adjacent neurons. Astrocytes are essential for the formation and maintenance of the BBB by providing secreted factors that lead to the adequate association between the cells of the BBB and the formation of strong tight junctions. Under neurological disorders, such as chronic cerebral ischemia, brain trauma, Epilepsy, Alzheimer and Parkinson’s Diseases, a disruption of the BBB takes place, involving a lost in the permeability of the barrier and phenotypical changes in both the ECs and astrocytes. In this aspect, it has been established that the process of reactive gliosis is a common feature of astrocytes during BBB disruption, which has a detrimental effect on the barrier function and a subsequent damage in neuronal survival. In this review we discuss the implications of astrocyte functions in the protection of the BBB, and in the development of Parkinson’s disease (PD) and related disorders. Additionally, we highlight the current and future strategies in astrocyte protection aimed at the development of restorative therapies for the BBB in pathological conditions. PMID:25136294

  5. Transport of paclitaxel (Taxol) across the blood-brain barrier in vitro and in vivo

    PubMed Central

    Fellner, Stephan; Bauer, Björn; Miller, David S.; Schaffrik, Martina; Fankhänel, Martina; Spruß, Thilo; Bernhardt, Günther; Graeff, Claudia; Färber, Lothar; Gschaidmeier, Harald; Buschauer, Armin; Fricker, Gert

    2002-01-01

    Paclitaxel concentrations in the brain are very low after intravenous injection. Since paclitaxel is excluded from some tumors by p-glycoprotein (p-gp), the same mechanism may prevent entry into the brain. In vitro, paclitaxel transport was examined in capillaries from rat brains by confocal microscopy using BODIPY Fl-paclitaxel. Western blots and immunostaining demonstrated apical expression of p-gp in isolated endothelial cells, vessels, and tissue. Secretion of BODIPY Fl-paclitaxel into capillary lumens was specific and energy-dependent. Steady state luminal fluorescence significantly exceeded cellular fluorescence and was reduced by NaCN, paclitaxel, and SDZ PSC-833 (valspodar), a p-gp blocker. Leukotriene C4 (LTC4), an Mrp2-substrate, had no effect. Luminal accumulation of NBDL-cyclosporin, a p-gp substrate, was inhibited by paclitaxel. In vivo, paclitaxel levels in the brain, liver, kidney, and plasma of nude mice were determined after intravenous injection. Co-administration of valspodar led to increased paclitaxel levels in brains compared to monotherapy. Therapeutic relevance was proven for nude mice with implanted intracerebral human U-118 MG glioblastoma. Whereas paclitaxel did not affect tumor volume, co-administration of paclitaxel (intravenous) and PSC833 (peroral) reduced tumor volume by 90%. Thus, p-gp is an important obstacle preventing paclitaxel entry into the brain, and inhibition of this transporter allows the drug to reach sensitive tumors within the CNS. PMID:12417570

  6. The role of the blood-brain barrier in the development and treatment of migraine and other pain disorders.

    PubMed

    DosSantos, Marcos F; Holanda-Afonso, Rosenilde C; Lima, Rodrigo L; DaSilva, Alexandre F; Moura-Neto, Vivaldo

    2014-01-01

    The function of the blood-brain barrier (BBB) related to chronic pain has been explored for its classical role in regulating the transcellular and paracellular transport, thus controlling the flow of drugs that act at the central nervous system, such as opioid analgesics (e.g., morphine) and non-steroidal anti-inflammatory drugs. Nonetheless, recent studies have raised the possibility that changes in the BBB permeability might be associated with chronic pain. For instance, changes in the relative amounts of occludin isoforms, resulting in significant increases in the BBB permeability, have been demonstrated after inflammatory hyperalgesia. Furthermore, inflammatory pain produces structural changes in the P-glycoprotein, the major efflux transporter at the BBB. One possible explanation for these findings is the action of substances typically released at the site of peripheral injuries that could lead to changes in the brain endothelial permeability, including substance P, calcitonin gene-related peptide, and interleukin-1 beta. Interestingly, inflammatory pain also results in microglial activation, which potentiates the BBB damage. In fact, astrocytes and microglia play a critical role in maintaining the BBB integrity and the activation of those cells is considered a key mechanism underlying chronic pain. Despite the recent advances in the understanding of BBB function in pain development as well as its interference in the efficacy of analgesic drugs, there remain unknowns regarding the molecular mechanisms involved in this process. In this review, we explore the connection between the BBB as well as the blood-spinal cord barrier and blood-nerve barrier, and pain, focusing on cellular and molecular mechanisms of BBB permeabilization induced by inflammatory or neuropathic pain and migraine. PMID:25339863

  7. Inhibition of chemokine-like factor 1 improves blood-brain barrier dysfunction in rats following focal cerebral ischemia.

    PubMed

    Kong, Ling-Lei; Wang, Zhi-Yuan; Hu, Jin-Feng; Yuan, Yu-He; Li, Hua; Chen, Nai-Hong

    2016-08-01

    Disruption of blood-brain barrier (BBB) and subsequent edema are major contributors to the pathogenesis of ischemic stroke, and the current clinical therapy remains unsatisfied. Chemokine-like factor 1 (CKLF1), as a novel C-C chemokine, plays important roles in immune response. The expression of CKLF1 increased after focal cerebral ischemia and inhibition of CKLF1 activity showed neuroprotective effect by alleviating infiltration of neutrophil and neuron apoptosis in cerebral ischemia. However, few studies have focused on the role of CKLF1 on BBB integrity. The objective of present study was to investigate the role of CKLF1 on BBB integrity by applying anti-CKLF1 antibodies in rat focal cerebral ischemia and reperfusion model. Brain water content, Evans blue leakage and the expression of aquaporin-4 (AQP-4), matrix metalloproteinase-9 (MMP-9), Zonula Occludens-1 (ZO-1) and Occludin were measured. After treatment with anti-CKLF1 antibody, brain water content and Evans blue leakage in ipsilateral hemisphere were decreased in a dose-dependent manner at 24h after reperfusion, but not changed in contralateral hemisphere. Anti-CKLF1 antibody reduced the expression of AQP-4 and MMP-9, and upregulated the expression of ZO-1 and Occludin. These results suggest that CKLF1 is involved in BBB disruption after reperfusion. Inhibition of CKLF1 protects against cerebral ischemia by maintaining BBB integrity, possibly via inhibiting the expression of AQP-4 and MMP-9, and increasing the expression of tight junction protein. PMID:27283776

  8. Drugs of abuse and blood-brain barrier endothelial dysfunction: A focus on the role of oxidative stress.

    PubMed

    Sajja, Ravi K; Rahman, Shafiqur; Cucullo, Luca

    2016-03-01

    Psychostimulants and nicotine are the most widely abused drugs with a detrimental impact on public health globally. While the long-term neurobehavioral deficits and synaptic perturbations are well documented with chronic use of methamphetamine, cocaine, and nicotine, emerging human and experimental studies also suggest an increasing incidence of neurovascular complications associated with drug abuse. Short- or long-term administration of psychostimulants or nicotine is known to disrupt blood-brain barrier (BBB) integrity/function, thus leading to an increased risk of brain edema and neuroinflammation. Various pathophysiological mechanisms have been proposed to underlie drug abuse-induced BBB dysfunction suggesting a central and unifying role for oxidative stress in BBB endothelium and perivascular cells. This review discusses drug-specific effects of methamphetamine, cocaine, and tobacco smoking on brain microvascular crisis and provides critical assessment of oxidative stress-dependent molecular pathways focal to the global compromise of BBB. Additionally, given the increased risk of human immunodeficiency virus (HIV) encephalitis in drug abusers, we have summarized the synergistic pathological impact of psychostimulants and HIV infection on BBB integrity with an emphasis on unifying role of endothelial oxidative stress. This mechanistic framework would guide further investigations on specific molecular pathways to accelerate therapeutic approaches for the prevention of neurovascular deficits by drugs of abuse. PMID:26661236

  9. Disruption in the Blood-Brain Barrier: The Missing Link between Brain and Body Inflammation in Bipolar Disorder?

    PubMed Central

    Patel, Jay P.; Frey, Benicio N.

    2015-01-01

    The blood-brain barrier (BBB) regulates the transport of micro- and macromolecules between the peripheral blood and the central nervous system (CNS) in order to maintain optimal levels of essential nutrients and neurotransmitters in the brain. In addition, the BBB plays a critical role protecting the CNS against neurotoxins. There has been growing evidence that BBB disruption is associated with brain inflammatory conditions such as Alzheimer's disease and multiple sclerosis. Considering the increasing role of inflammation and oxidative stress in the pathophysiology of bipolar disorder (BD), here we propose a novel model wherein transient or persistent disruption of BBB integrity is associated with decreased CNS protection and increased permeability of proinflammatory (e.g., cytokines, reactive oxygen species) substances from the peripheral blood into the brain. These events would trigger the activation of microglial cells and promote localized damage to oligodendrocytes and the myelin sheath, ultimately compromising myelination and the integrity of neural circuits. The potential implications for research in this area and directions for future studies are discussed. PMID:26075104

  10. Enolase of Streptococcus Suis Serotype 2 Enhances Blood-Brain Barrier Permeability by Inducing IL-8 Release.

    PubMed

    Sun, Yingying; Li, Na; Zhang, Jing; Liu, Hongtao; Liu, Jianfang; Xia, Xiaojing; Sun, Changjiang; Feng, Xin; Gu, Jingmin; Du, Chongtao; Han, Wenyu; Lei, Liancheng

    2016-04-01

    Streptococcus suis serotype 2 (SS2) is an emerging zoonosis, and meningitis is the most frequent clinical manifestation, but mechanism of its virulent factor, enolase (Eno), is unknown in meningitis. In this study, Eno was inducibly expressed and added to an in vitro Transwell co-culture model of the blood-brain barrier (BBB) consisted of porcine brain microvascular endothelial cells (PBMECs) and astrocytes (ACs), the results showed that Eno induces a significant increase in BBB permeability and promotes the release of IL-8 et al. cytokines. Furthermore, IL-8 could significantly destroy the integrity of the BBB model in vitro. In mice models administered Eno for 24 h, Eno could significantly promote Evans blue (EB) moving from the blood to the brain and significantly increased the serum and brain levels of IL-8, as detected by ELISA. While G31P (IL-8 receptor antagonist) significantly decreased the concentration of EB in the brains of mice injected with Eno. The present study demonstrated that SS2 Eno may play an important role in disrupting BBB integrity by prompting IL-8 release. PMID:26732390

  11. Lipopolysaccharide potentiates polychlorinated biphenyl-induced disruption of the blood-brain barrier via TLR4/IRF-3 signaling.

    PubMed

    Choi, Jeong June; Choi, Yean Jung; Chen, Lei; Zhang, Bei; Eum, Sung Yong; Abreu, Maria T; Toborek, Michal

    2012-12-16

    Exposure to polychlorinated biphenyls (PCBs) is associated with numerous adverse health effects. Although the main route of exposure to PCBs is through the gastrointestinal tract, little is known about the contribution of the gut to the health effects of PCBs. We hypothesize that PCBs can disrupt intestinal integrity, causing lipopolysaccharide (LPS) translocation into the bloodstream and potentiation of the systemic toxicity of PCBs. C57BL/6 mice were exposed to individual PCB congeners by oral gavage, followed by the assessment of small intestine morphology and plasma levels of proinflammatory mediators. In addition, mice and human brain endothelial cells were exposed to PCB118 in the presence or absence of LPS to evaluate the contribution of LPS to PCB-induced toxicity at the blood-brain barrier (BBB) level. Oral administration of PCB153, PCB118, or PCB126 disrupted intestinal morphology and increased plasma levels of LPS and proinflammatory cytokines. Direct injection of LPS and PCB118 into the cerebral microvasculature resulted in synergistic disruption of BBB integrity and decreased expression of tight junction proteins in brain microvessels. In vitro experiments confirmed these effects and indicated that stimulation of the toll-like receptor 4 (TLR4) pathway can be responsible for these effects via activation of interferon regulatory factor-3 (IRF-3). These results indicate that LPS may be a contributing factor in PCB-induced dysfunction of the brain endothelium via stimulation of the TLR4/IRF-3 pathway. PMID:22906770

  12. A retinoic acid-enhanced, multicellular human blood-brain barrier model derived from stem cell sources

    NASA Astrophysics Data System (ADS)

    Lippmann, Ethan S.; Al-Ahmad, Abraham; Azarin, Samira M.; Palecek, Sean P.; Shusta, Eric V.

    2014-02-01

    Blood-brain barrier (BBB) models are often used to investigate BBB function and screen brain-penetrating therapeutics, but it has been difficult to construct a human model that possesses an optimal BBB phenotype and is readily scalable. To address this challenge, we developed a human in vitro BBB model comprising brain microvascular endothelial cells (BMECs), pericytes, astrocytes and neurons derived from renewable cell sources. First, retinoic acid (RA) was used to substantially enhance BBB phenotypes in human pluripotent stem cell (hPSC)-derived BMECs, particularly through adherens junction, tight junction, and multidrug resistance protein regulation. RA-treated hPSC-derived BMECs were subsequently co-cultured with primary human brain pericytes and human astrocytes and neurons derived from human neural progenitor cells (NPCs) to yield a fully human BBB model that possessed significant tightness as measured by transendothelial electrical resistance (~5,000 Ωxcm2). Overall, this scalable human BBB model may enable a wide range of neuroscience studies.

  13. Modeling localized delivery of Doxorubicin to the brain following focused ultrasound enhanced blood-brain barrier permeability

    NASA Astrophysics Data System (ADS)

    Nhan, Tam; Burgess, Alison; Lilge, Lothar; Hynynen, Kullervo

    2014-10-01

    Doxorubicin (Dox) is a well-established chemotherapeutic agent, however it has limited efficacy in treating brain malignancies due to the presence of the blood-brain barrier (BBB). Recent preclinical studies have demonstrated that focused ultrasound induced BBB disruption (BBBD) enables efficient delivery of Dox to the brain. For future treatment planning of BBBD-based drug delivery, it is crucial to establish a mathematical framework to predict the effect of transient BBB permeability enhancement on the spatiotemporal distribution of Dox at the targeted area. The constructed model considers Dox concentrations within three compartments (plasma, extracellular, intracellular) that are governed by various transport processes (e.g. diffusion in interstitial space, exchange across vessel wall, clearance by cerebral spinal fluid, uptake by brain cells). By examining several clinical treatment aspects (e.g. sonication scheme, permeability enhancement, injection mode), our simulation results support the experimental findings of optimal interval delay between two consecutive sonications and therapeutically-sufficient intracellular concentration with respect to transfer constant Ktrans range of 0.01-0.03 min-1. Finally, the model suggests that infusion over a short duration (20-60 min) should be employed along with single-sonication or multiple-sonication at 10 min interval to ensure maximum delivery to the intracellular compartment while attaining minimal cardiotoxicity via suppressing peak plasma concentration.

  14. Blood-Brain Barrier Opening in Behaving Non-Human Primates via Focused Ultrasound with Systemically Administered Microbubbles

    NASA Astrophysics Data System (ADS)

    Downs, Matthew E.; Buch, Amanda; Karakatsani, Maria Eleni; Konofagou, Elisa E.; Ferrera, Vincent P.

    2015-10-01

    Over the past fifteen years, focused ultrasound coupled with intravenously administered microbubbles (FUS) has been proven an effective, non-invasive technique to open the blood-brain barrier (BBB) in vivo. Here we show that FUS can safely and effectively open the BBB at the basal ganglia and thalamus in alert non-human primates (NHP) while they perform a behavioral task. The BBB was successfully opened in 89% of cases at the targeted brain regions of alert NHP with an average volume of opening 28% larger than prior anesthetized FUS procedures. Safety (lack of edema or microhemorrhage) of FUS was also improved during alert compared to anesthetized procedures. No physiological effects (change in heart rate, motor evoked potentials) were observed during any of the procedures. Furthermore, the application of FUS did not disrupt reaching behavior, but in fact improved performance by decreasing reaction times by 23 ms, and significantly decreasing touch error by 0.76 mm on average.

  15. Permeability of endothelial and astrocyte cocultures: in vitro blood-brain barrier models for drug delivery studies.

    PubMed

    Li, Guanglei; Simon, Melissa J; Cancel, Limary M; Shi, Zhong-Dong; Ji, Xinying; Tarbell, John M; Morrison, Barclay; Fu, Bingmei M

    2010-08-01

    The blood-brain barrier (BBB) is a major obstacle for drug delivery to the brain. To seek for in vitro BBB models that are more accessible than animals for investigating drug transport across the BBB, we compared four in vitro cultured cell models: endothelial monoculture (bEnd3 cell line), coculture of bEnd3 and primary rat astrocytes (coculture), coculture with collagen type I and IV mixture, and coculture with Matrigel. The expression of the BBB tight junction proteins in these in vitro models was assessed using RT-PCR and immunofluorescence. We also quantified the hydraulic conductivity (L (p)), transendothelial electrical resistance (TER) and diffusive solute permeability (P) of these models to three solutes: TAMRA, Dextran 10K and Dextran 70K. Our results show that L (p) and P of the endothelial monoculture and coculture models are not different from each other. Compared with in vivo permeability data from rat pial microvessels, P of the endothelial monoculture and coculture models are not significantly different from in vivo data for Dextran 70K, but they are 2-4 times higher for TAMRA and Dextran 10K. This suggests that the endothelial monoculture and all of the coculture models are fairly good models for studying the transport of relatively large solutes across the BBB. PMID:20361260

  16. No Dynamic Changes in Blood-brain Barrier Permeability Occur in Developing Rats During Local Cortex Exposure to Microwaves.

    PubMed

    Masuda, Hiroshi; Hirota, Shogo; Ushiyama, Akira; Hirata, Akimasa; Arima, Takuji; Kawai, Hiroki; Wake, Kanako; Watanabe, Soichi; Taki, Masao; Nagai, Akiko; Ohkubo, Chiyoji

    2015-01-01

    Little information is available about the effects of exposure to radiofrequency electromagnetic fields (RF) on cerebral microcirculation during rat developmental stages. We investigated whether the permeability of the blood-brain barrier (BBB) in juvenile and young adult rats was modified during local cortex exposure to RF under non-thermal conditions. The cortex tissue targeted was locally exposed to 1457 MHz RF at an average specific absorption rate of 2.0 W/kg in the target area for 50 min and permeability changes in the BBB of the pia mater were measured directly, using intravital fluorescence microscopy. There was no significant difference in extravasation of intravenously-injected dye between exposed and sham-exposed groups of either category of rats. No histological evidence of albumin leakage was found in any of the brains just after exposure, indicating that no traces of BBB disruption remained. These findings suggest that no dynamic changes occurred in BBB permeability of the rats at either of these developmental stages, even during local RF exposure at non-thermal levels. PMID:25977380

  17. Curcumin-releasing mechanically adaptive intracortical implants improve the proximal neuronal density and blood-brain barrier stability.

    PubMed

    Potter, Kelsey A; Jorfi, Mehdi; Householder, Kyle T; Foster, E Johan; Weder, Christoph; Capadona, Jeffrey R

    2014-05-01

    The cellular and molecular mechanisms by which neuroinflammatory pathways respond to and propagate the reactive tissue response to intracortical microelectrodes remain active areas of research. We previously demonstrated that both the mechanical mismatch between rigid implants and the much softer brain tissue, as well as oxidative stress, contribute to the neurodegenerative reactive tissue response to intracortical implants. In this study, we utilize physiologically responsive, mechanically adaptive polymer implants based on poly(vinyl alcohol) (PVA), with the capability to also locally administer the antioxidant curcumin. The goal of this study is to investigate if the combination of two independently effective mechanisms - softening of the implant and antioxidant release - leads to synergistic effects in vivo. Over the first 4weeks of the implantation, curcumin-releasing, mechanically adaptive implants were associated with higher neuron survival and a more stable blood-brain barrier at the implant-tissue interface than the neat PVA controls. 12weeks post-implantation, the benefits of the curcumin release were lost, and both sets of compliant materials (with and without curcumin) had no statistically significant differences in neuronal density distribution profiles. Overall, however, the curcumin-releasing softening polymer implants cause minimal implant-mediated neuroinflammation, and embody the new concept of localized drug delivery from mechanically adaptive intracortical implants. PMID:24468582

  18. Feasibility Study of the Permeability and Uptake of Mesoporous Silica Nanoparticles across the Blood-Brain Barrier

    PubMed Central

    Baghirov, Habib; Karaman, Didem; Viitala, Tapani; Duchanoy, Alain; Lou, Yan-Ru; Mamaeva, Veronika; Pryazhnikov, Evgeny; Khiroug, Leonard; de Lange Davies, Catharina; Sahlgren, Cecilia; Rosenholm, Jessica M.

    2016-01-01

    Drug delivery into the brain is impeded by the blood-brain-barrier (BBB) that filters out the vast majority of drugs after systemic administration. In this work, we assessed the transport, uptake and cytotoxicity of promising drug nanocarriers, mesoporous silica nanoparticles (MSNs), in in vitro models of the BBB. RBE4 rat brain endothelial cells and Madin-Darby canine kidney epithelial cells, strain II, were used as BBB models. We studied spherical and rod-shaped MSNs with the following modifications: bare MSNs and MSNs coated with a poly(ethylene glycol)-poly(ethylene imine) (PEG-PEI) block copolymer. In transport studies, MSNs showed low permeability, whereas the results of the cellular uptake studies suggest robust uptake of PEG-PEI-coated MSNs. None of the MSNs showed significant toxic effects in the cell viability studies. While the shape effect was detectable but small, especially in the real-time surface plasmon resonance measurements, coating with PEG-PEI copolymers clearly facilitated the uptake of MSNs. Finally, we evaluated the in vivo detectability of one of the best candidates, i.e. the copolymer-coated rod-shaped MSNs, by two-photon in vivo imaging in the brain vasculature. The particles were clearly detectable after intravenous injection and caused no damage to the BBB. Thus, when properly designed, the uptake of MSNs could potentially be utilized for the delivery of drugs into the brain via transcellular transport. PMID:27547955

  19. Absence of Glial α-Dystrobrevin Causes Abnormalities of the Blood-Brain Barrier and Progressive Brain Edema*

    PubMed Central

    Lien, Chun Fu; Mohanta, Sarajo Kumar; Frontczak-Baniewicz, Malgorzata; Swinny, Jerome D.; Zablocka, Barbara; Górecki, Dariusz C.

    2012-01-01

    The blood-brain barrier (BBB) plays a key role in maintaining brain functionality. Although mammalian BBB is formed by endothelial cells, its function requires interactions between endotheliocytes and glia. To understand the molecular mechanisms involved in these interactions is currently a major challenge. We show here that α-dystrobrevin (α-DB), a protein contributing to dystrophin-associated protein scaffolds in astrocytic endfeet, is essential for the formation and functioning of BBB. The absence of α-DB in null brains resulted in abnormal brain capillary permeability, progressively escalating brain edema, and damage of the neurovascular unit. Analyses in situ and in two-dimensional and three-dimensional in vitro models of BBB containing α-DB-null astrocytes demonstrated these abnormalities to be associated with loss of aquaporin-4 water and Kir4.1 potassium channels from glial endfeet, formation of intracellular vacuoles in α-DB-null astrocytes, and defects of the astrocyte-endothelial interactions. These caused deregulation of tight junction proteins in the endothelia. Importantly, α-DB but not dystrophins showed continuous expression throughout development in BBB models. Thus, α-DB emerges as a central organizer of dystrophin-associated protein in glial endfeet and a rare example of a glial protein with a role in maintaining BBB function. Its abnormalities might therefore lead to BBB dysfunction. PMID:23043099

  20. Radiofrequency-radiation exposure does not induce detectable leakage of albumin across the blood-brain barrier.

    PubMed

    McQuade, Jill M S; Merritt, James H; Miller, Stephanie A; Scholin, Terri; Cook, Michael C; Salazar, Alexander; Rahimi, Omid B; Murphy, Michael R; Mason, Patrick A

    2009-05-01

    The blood-brain barrier (BBB) consists of tight junctions between the endothelial cells that line the capillaries in the central nervous system. This structure protects the brain, and neurological damage could occur if it is compromised. Several publications by researchers at Lund University have reported alterations in the BBB after exposure to low-power 915 MHz energy. These publications increased the level of concern regarding the safety of wireless communication devices such as mobile phones. We performed a confirmation study designed to determine whether the BBB is altered in rats exposed in a transverse electromagnetic (TEM) transmission line cell to 915 MHz energy at parameters similar to those in the Lund University studies. Unanesthetized rats were exposed for 30 min to either continuous-wave or modulated (16 or 217 Hz) 915 MHz energy at power levels resulting in whole-body specific absorption rates (SARs) of 0.0018-20 W/kg. Albumin immunohistochemistry was performed on perfused brain tissue sections to determine the integrity of the BBB. Chi-square analysis revealed no significant increase in albumin extravasation in any of the exposed animals compared to the sham-exposed or home cage control animals. PMID:19580497

  1. Feasibility study of a single-element transcranial focused ultrasound system for blood-brain barrier opening

    NASA Astrophysics Data System (ADS)

    Marquet, Fabrice; Tung, Yao-Sheng; Teichert, Tobias; Ferrera, Vincent P.; Konofagou, Elisa E.

    2012-10-01

    The blood-brain barrier (BBB) is a specialized vascular system that impedes entry of all large and the vast majority of small molecules including the most potent CNS disease therapeutic agents from entering from the lumen into the brain parenchyma. Microbubble-enhanced, focused ultrasound (ME-FUS) has been previously shown to disrupt noninvasively, selectively, and transiently the BBB in small animals in vivo. The study addresses the focusing properties of single-element transducers at intermediate frequencies (500 kHz) through primate and human skulls, targeting clinically relevant targets extracted from 3D brain atlases such as the hippocampus and the basal ganglia, which are typically affected by early Alzheimer's and Parkinson's disease, respectively. A preliminary in vivo study was performed to study the frequency dependence of BBB opening parameters in mice. Then, feasibility of transcranial ME-FUS BBB opening in non-human primates was