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Furtado A, Duarte AC, Costa AR, Gonçalves I, Santos CRA, Gallardo E, Quintela T. Circadian ABCG2 Expression Influences the Brain Uptake of Donepezil across the Blood-Cerebrospinal Fluid Barrier. Int J Mol Sci 2024; 25:5014. [PMID: 38732233 PMCID: PMC11084460 DOI: 10.3390/ijms25095014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 04/21/2024] [Accepted: 04/29/2024] [Indexed: 05/13/2024] Open
Abstract
Donepezil (DNPZ) is a cholinesterase inhibitor used for the management of Alzheimer's disease (AD) and is dependent on membrane transporters such as ABCG2 to actively cross brain barriers and reach its target site of action in the brain. Located in the brain ventricles, the choroid plexus (CP) forms an interface between the cerebrospinal fluid (CSF) and the bloodstream, known as the blood-CSF barrier (BCSFB). Historically, the BCSFB has received little attention as a potential pathway for drug delivery to the central nervous system (CNS). Nonetheless, this barrier is presently viewed as a dynamic transport interface that limits the traffic of molecules into and out of the CNS through the presence of membrane transporters, with parallel activity with the BBB. The localization and expression of drug transporters in brain barriers represent a huge obstacle for drug delivery to the brain and a major challenge for the development of therapeutic approaches to CNS disorders. The widespread interest in understanding how circadian clocks modulate many processes that define drug delivery in order to predict the variability in drug safety and efficacy is the next bridge to improve effective treatment. In this context, this study aims at characterizing the circadian expression of ABCG2 and DNPZ circadian transport profile using an in vitro model of the BCSFB. We found that ABCG2 displays a circadian pattern and DNPZ is transported in a circadian way across this barrier. This study will strongly impact on the capacity to modulate the BCSFB in order to control the penetration of DNPZ into the brain and improve therapeutic strategies for the treatment of AD according to the time of the day.
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Affiliation(s)
- André Furtado
- CICS-UBI, Health Sciences Research Centre, Faculty of Health Sciences, Universityof Beira Interior, Avenida Infante Dom Henrique, 6200-506 Covilhã, Portugal
| | - Ana Catarina Duarte
- CICS-UBI, Health Sciences Research Centre, Faculty of Health Sciences, Universityof Beira Interior, Avenida Infante Dom Henrique, 6200-506 Covilhã, Portugal
| | - Ana R. Costa
- CICS-UBI, Health Sciences Research Centre, Faculty of Health Sciences, Universityof Beira Interior, Avenida Infante Dom Henrique, 6200-506 Covilhã, Portugal
| | - Isabel Gonçalves
- CICS-UBI, Health Sciences Research Centre, Faculty of Health Sciences, Universityof Beira Interior, Avenida Infante Dom Henrique, 6200-506 Covilhã, Portugal
| | - Cecília R. A. Santos
- CICS-UBI, Health Sciences Research Centre, Faculty of Health Sciences, Universityof Beira Interior, Avenida Infante Dom Henrique, 6200-506 Covilhã, Portugal
| | - Eugenia Gallardo
- Laboratório de Fármaco-Toxicologia-UBIMedical, Universidade da Beira Interior, 6200-506 Covilhã, Portugal
| | - Telma Quintela
- CICS-UBI, Health Sciences Research Centre, Faculty of Health Sciences, Universityof Beira Interior, Avenida Infante Dom Henrique, 6200-506 Covilhã, Portugal
- Faculty of Health Sciences, Instituto Politécnico da Guarda, 6300-559 Guarda, Portugal
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Dabbagh F, Schroten H, Schwerk C. In Vitro Models of the Blood–Cerebrospinal Fluid Barrier and Their Applications in the Development and Research of (Neuro)Pharmaceuticals. Pharmaceutics 2022; 14:pharmaceutics14081729. [PMID: 36015358 PMCID: PMC9412499 DOI: 10.3390/pharmaceutics14081729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 08/11/2022] [Accepted: 08/16/2022] [Indexed: 11/30/2022] Open
Abstract
The pharmaceutical research sector has been facing the challenge of neurotherapeutics development and its inherited high-risk and high-failure-rate nature for decades. This hurdle is partly attributable to the presence of brain barriers, considered both as obstacles and opportunities for the entry of drug substances. The blood–cerebrospinal fluid (CSF) barrier (BCSFB), an under-studied brain barrier site compared to the blood–brain barrier (BBB), can be considered a potential therapeutic target to improve the delivery of CNS therapeutics and provide brain protection measures. Therefore, leveraging robust and authentic in vitro models of the BCSFB can diminish the time and effort spent on unproductive or redundant development activities by a preliminary assessment of the desired physiochemical behavior of an agent toward this barrier. To this end, the current review summarizes the efforts and progresses made to this research area with a notable focus on the attribution of these models and applied techniques to the pharmaceutical sector and the development of neuropharmacological therapeutics and diagnostics. A survey of available in vitro models, with their advantages and limitations and cell lines in hand will be provided, followed by highlighting the potential applications of such models in the (neuro)therapeutics discovery and development pipelines.
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Roy PK, Rajesh Y, Mandal M. Therapeutic targeting of membrane-associated proteins in central nervous system tumors. Exp Cell Res 2021; 406:112760. [PMID: 34339674 DOI: 10.1016/j.yexcr.2021.112760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/28/2021] [Accepted: 07/28/2021] [Indexed: 12/09/2022]
Abstract
The activity of the most complex system, the central nervous system (CNS) is profoundly regulated by a huge number of membrane-associated proteins (MAP). A minor change stimulates immense chemical changes and the elicited response is organized by MAP, which acts as a receptor of that chemical or channel enabling the flow of ions. Slight changes in the activity or expression of these MAPs lead to severe consequences such as cognitive disorders, memory loss, or cancer. CNS tumors are heterogeneous in nature and hard-to-treat due to random mutations in MAPs; like as overexpression of EGFRvIII/TGFβR/VEGFR, change in adhesion molecules α5β3 integrin/SEMA3A, imbalance in ion channel proteins, etc. Extensive research is under process for developing new therapeutic approaches using these proteins such as targeted cytotoxic radiotherapy, drug-delivery, and prodrug activation, blocking of receptors like GluA1, developing viral vector against cell surface receptor. The combinatorial approach of these strategies along with the conventional one might be more potential. Henceforth, our review focuses on in-depth analysis regarding MAPs aiming for a better understanding for developing an efficient therapeutic approach for targeting CNS tumors.
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Affiliation(s)
- Pritam Kumar Roy
- School of Medical Science and Technology, Indian Institute of Technology Kharagpur, India
| | - Yetirajam Rajesh
- Department of Human and Molecular Genetics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Mahitosh Mandal
- School of Medical Science and Technology, Indian Institute of Technology Kharagpur, India.
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Solár P, Zamani A, Kubíčková L, Dubový P, Joukal M. Choroid plexus and the blood-cerebrospinal fluid barrier in disease. Fluids Barriers CNS 2020; 17:35. [PMID: 32375819 PMCID: PMC7201396 DOI: 10.1186/s12987-020-00196-2] [Citation(s) in RCA: 129] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 04/22/2020] [Indexed: 01/08/2023] Open
Abstract
The choroid plexus (CP) forming the blood-cerebrospinal fluid (B-CSF) barrier is among the least studied structures of the central nervous system (CNS) despite its clinical importance. The CP is an epithelio-endothelial convolute comprising a highly vascularized stroma with fenestrated capillaries and a continuous lining of epithelial cells joined by apical tight junctions (TJs) that are crucial in forming the B-CSF barrier. Integrity of the CP is critical for maintaining brain homeostasis and B-CSF barrier permeability. Recent experimental and clinical research has uncovered the significance of the CP in the pathophysiology of various diseases affecting the CNS. The CP is involved in penetration of various pathogens into the CNS, as well as the development of neurodegenerative (e.g., Alzheimer´s disease) and autoimmune diseases (e.g., multiple sclerosis). Moreover, the CP was shown to be important for restoring brain homeostasis following stroke and trauma. In addition, new diagnostic methods and treatment of CP papilloma and carcinoma have recently been developed. This review describes and summarizes the current state of knowledge with regard to the roles of the CP and B-CSF barrier in the pathophysiology of various types of CNS diseases and sets up the foundation for further avenues of research.
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Affiliation(s)
- Peter Solár
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, CZ-625 00, Brno, Czech Republic
- Department of Neurosurgery, Faculty of Medicine, Masaryk University and St. Anne´s University Hospital Brno, Pekařská 53, CZ-656 91, Brno, Czech Republic
| | - Alemeh Zamani
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, CZ-625 00, Brno, Czech Republic
| | - Lucie Kubíčková
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, CZ-625 00, Brno, Czech Republic
| | - Petr Dubový
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, CZ-625 00, Brno, Czech Republic
| | - Marek Joukal
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, CZ-625 00, Brno, Czech Republic.
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5
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Koehn LM, Dziegielewska KM, Møllgård K, Saudrais E, Strazielle N, Ghersi-Egea JF, Saunders NR, Habgood MD. Developmental differences in the expression of ABC transporters at rat brain barrier interfaces following chronic exposure to diallyl sulfide. Sci Rep 2019; 9:5998. [PMID: 30979952 PMCID: PMC6461637 DOI: 10.1038/s41598-019-42402-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 03/28/2019] [Indexed: 02/07/2023] Open
Abstract
Many pregnant women and prematurely born infants require medication for clinical conditions including cancer, cardiac defects and psychiatric disorders. In adults drug transfer from blood into brain is mostly restricted by efflux mechanisms (ATP-binding cassette, ABC transporters). These mechanisms have been little studied during brain development. Here expression of eight ABC transporters (abcb1a, abcb1b, abcg2, abcc1, abcc2, abcc3, abcc4, abcc5) and activity of conjugating enzyme glutathione-s-transferase (GST) were measured in livers, brain cortices (blood-brain-barrier) and choroid plexuses (blood-cerebrospinal fluid, CSF, barrier) during postnatal rat development. Controls were compared to animals chronically injected (4 days, 200 mg/kg/day) with known abcb1a inducer diallyl sulfide (DAS). Results reveal both tissue- and age-dependent regulation. In liver abcb1a and abcc3 were up-regulated at all ages. In cortex abcb1a/b, abcg2 and abcc4/abcc5 were up-regulated in adults only, while in choroid plexus abcb1a and abcc2 were up-regulated only at P14. DAS treatment increased GST activity in livers, but not in cortex or choroid plexuses. Immunocytochemistry of ABC transporters at the CSF-brain interface showed that PGP and BCRP predominated in neuroepithelium while MRP2/4/5 were prominent in adult ependyma. These results indicate an age-related capacity of brain barriers to dynamically regulate their defence mechanisms when chronically challenged by xenobiotic compounds.
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Affiliation(s)
- Liam M Koehn
- Department of Pharmacology and Therapeutics, The University of Melbourne, Melbourne, Victoria, Australia
| | - Katarzyna M Dziegielewska
- Department of Pharmacology and Therapeutics, The University of Melbourne, Melbourne, Victoria, Australia
| | - Kjeld Møllgård
- Institute of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Elodie Saudrais
- IBIP facility and Fluid team, Lyon Neuroscience Research center, NSERM U1028 CNRS UMR5292, Université de Lyon-1, Lyon, France
| | - Nathalie Strazielle
- IBIP facility and Fluid team, Lyon Neuroscience Research center, NSERM U1028 CNRS UMR5292, Université de Lyon-1, Lyon, France.,Brain-I, Lyon, France
| | - Jean-Francois Ghersi-Egea
- IBIP facility and Fluid team, Lyon Neuroscience Research center, NSERM U1028 CNRS UMR5292, Université de Lyon-1, Lyon, France
| | - Norman R Saunders
- Department of Pharmacology and Therapeutics, The University of Melbourne, Melbourne, Victoria, Australia.
| | - Mark D Habgood
- Department of Pharmacology and Therapeutics, The University of Melbourne, Melbourne, Victoria, Australia
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Prieto P, Blaauboer BJ, de Boer AG, Boveri M, Cecchelli R, Clemedson C, Coecke S, Forsby A, Galla HJ, Garberg P, Greenwood J, Price A, Tähti H. Blood-Brain Barrier In Vitro Models and Their Application in Toxicology: The Report and Recommendations of ECVAM Workshop 49,. Altern Lab Anim 2019; 32:37-50. [PMID: 15603552 DOI: 10.1177/026119290403200107] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Pilar Prieto
- ECVAM, Institute for Health & Consumer Protection, European Commission Joint Research Centre, 21020 Ispra (VA), Italy.
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Allegra S, Cardellino CS, Fatiguso G, Cusato J, De Nicolò A, Avataneo V, Bonora S, D'Avolio A, Di Perri G, Calcagno A. Effect of ABCC2 and ABCG2 Gene Polymorphisms and CSF-to-Serum Albumin Ratio on Ceftriaxone Plasma and Cerebrospinal Fluid Concentrations. J Clin Pharmacol 2018; 58:1550-1556. [PMID: 29873816 DOI: 10.1002/jcph.1266] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 05/11/2018] [Indexed: 12/17/2022]
Abstract
We measured ceftriaxone pharmacokinetics in patients' plasma and cerebrospinal fluid (CSF) and assessed the influence of biometric, demographic, genetic (ABCB1, ABCC2, ABCB11, ABCG2, and SLCO1A2 polymorphisms) and pathological features. Adult patients with signs and symptoms of central nervous system infections, receiving intravenous ceftriaxone, were enrolled. Ceftriaxone plasma and CSF concentrations were measured by high-precision liquid chromatographic methods; allelic discrimination was performed by real-time polymerase chain reaction. Forty-three patients were included: median ceftriaxone maximal concentration was 15,713 ng/mL in plasma and 3512 ng/mL in CSF with a CSF-to-plasma ratio of 0.3. ABCC2 1249 rs2273697 (P = .027) and ABCG2 1194+928 rs13120400 (P = .015) variants were significantly associated with CSF concentrations and CSF-to-plasma ratios. At linear regression analysis, CSF-to-serum albumin ratio was an independent predictor of ceftriaxone CSF concentrations (P = .001; also in those with intact blood-brain barrier: P = .031) and CSF-to-plasma ratio (P = .001; also in those with blood-brain barrier impairment: P = .040). We here report the role of transporters' genetic variants as well as of blood-brain barrier permeability in predicting ceftriaxone exposure in the central nervous system.
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Affiliation(s)
- Sarah Allegra
- Department of Medical Sciences, Unit of Infectious Diseases, University of Turin, Amedeo di Savoia Hospital, Turin, Italy
| | - Chiara Simona Cardellino
- Department of Medical Sciences, Unit of Infectious Diseases, University of Turin, Amedeo di Savoia Hospital, Turin, Italy
| | - Giovanna Fatiguso
- Department of Medical Sciences, Unit of Infectious Diseases, University of Turin, Amedeo di Savoia Hospital, Turin, Italy
| | - Jessica Cusato
- Department of Medical Sciences, Unit of Infectious Diseases, University of Turin, Amedeo di Savoia Hospital, Turin, Italy
| | - Amedeo De Nicolò
- Department of Medical Sciences, Unit of Infectious Diseases, University of Turin, Amedeo di Savoia Hospital, Turin, Italy
| | - Valeria Avataneo
- Department of Medical Sciences, Unit of Infectious Diseases, University of Turin, Amedeo di Savoia Hospital, Turin, Italy
| | - Stefano Bonora
- Department of Medical Sciences, Unit of Infectious Diseases, University of Turin, Amedeo di Savoia Hospital, Turin, Italy
| | - Antonio D'Avolio
- Department of Medical Sciences, Unit of Infectious Diseases, University of Turin, Amedeo di Savoia Hospital, Turin, Italy
| | - Giovanni Di Perri
- Department of Medical Sciences, Unit of Infectious Diseases, University of Turin, Amedeo di Savoia Hospital, Turin, Italy
| | - Andrea Calcagno
- Department of Medical Sciences, Unit of Infectious Diseases, University of Turin, Amedeo di Savoia Hospital, Turin, Italy
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Runtz L, Girard B, Toussenot M, Espallergues J, Fayd'Herbe De Maudave A, Milman A, deBock F, Ghosh C, Guérineau NC, Pascussi JM, Bertaso F, Marchi N. Hepatic and hippocampal cytochrome P450 enzyme overexpression during spontaneous recurrent seizures. Epilepsia 2017; 59:123-134. [PMID: 29125184 DOI: 10.1111/epi.13942] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/10/2017] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Available evidence points to a role of cytochrome P450 (Cyp) drug biotransformation enzymes in central nervous system diseases, including epilepsy. Deviations in drug pharmacokinetic profiles may impact therapeutic outcomes. Here, we ask whether spontaneous recurrent seizure (SRS) activity is sufficient to modulate the expression of major Cyp enzymes in the liver and brain. METHODS Unilateral intrahippocampal (IH) kainic acid (KA) injections were used to elicit nonconvulsive status epilepticus (SE), epileptogenesis, and SRS, as monitored by video-electroencephalography. Intraperitoneal (IP) KA injection was used to trigger generalized tonic-clonic SE. KA-injected mice and sham controls were sacrificed at 24-72 hours and 1 week post-SE (IH or IP KA), and during the chronic stage (SRS; 6 weeks post-IH KA). Liver and brain tissues were processed for histology, real-time quantitative polymerase chain reaction, Western blot, or microsomal enzymatic assay. Cyp2e1, Cyp3a13, glial fibrillary acidic protein (GFAP), IBA1, xenobiotic nuclear receptors nr1i2 (PXR), nr1i3 (CAR) and nr3c1 (glucocorticoid receptor [GR]) expression was examined. Serum samples were obtained to assay corticosterone levels, a GR activator. RESULTS A significant increase of Cyp3a13 and Cyp2e1 transcript level and protein expression was found in the liver and hippocampi during SRS, as compared to control mice. In the ipsilateral hippocampus, Cyp2e1 and Cyp3a protein upregulation during SRS positively correlated to GFAP expression. GFAP+ , and not IBA1+ , cells colocalized with Cyp2e1 or Cyp3a expression. In the liver, a trend increase in Cyp3a microsomal activity was found during SRS as compared to control mice. The transcript levels of the Cyp upstream regulators GR, xenobiotic nr1i2, and nr1i3 receptors were unchanged at SRS. Corticosterone levels, a GR ligand, were increased in the blood post-SE. SIGNIFICANCE SRS modifies Cyp expression in the liver and the hippocampus. Nuclear receptors or inflammatory pathways are candidate mechanisms of Cyp regulation during seizures.
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Affiliation(s)
- Leonie Runtz
- Laboratory of Cerebrovascular Mechanisms of Brain Disorders, Institute of Functional Genomics (UMR 5203 CNRS-U 1191 INSERM), Montpellier, France
| | - Benoit Girard
- Laboratory of Pathophysiology of Synaptic Transmission, Institute of Functional Genomics (UMR 5203 CNRS-U 1191 INSERM), Montpellier, France
| | - Marion Toussenot
- Laboratory of Cerebrovascular Mechanisms of Brain Disorders, Institute of Functional Genomics (UMR 5203 CNRS-U 1191 INSERM), Montpellier, France
| | | | - Alexis Fayd'Herbe De Maudave
- Laboratory of Cerebrovascular Mechanisms of Brain Disorders, Institute of Functional Genomics (UMR 5203 CNRS-U 1191 INSERM), Montpellier, France
| | - Alexandre Milman
- Ion channels in Neuronal Excitability and Diseases, Institute of Functional Genomics (UMR 5203 CNRS-U 1191 INSERM), Montpellier, France
| | - Frederic deBock
- Laboratory of Cerebrovascular Mechanisms of Brain Disorders, Institute of Functional Genomics (UMR 5203 CNRS-U 1191 INSERM), Montpellier, France
| | - Chaitali Ghosh
- Cerebrovascular Research, Cleveland Clinic, Cleveland, OH, USA
| | - Nathalie C Guérineau
- Ion channels in Neuronal Excitability and Diseases, Institute of Functional Genomics (UMR 5203 CNRS-U 1191 INSERM), Montpellier, France
| | - Jean-Marc Pascussi
- Laboratory of Self-Renewal and Differentiation of Epithelia, Institute of Functional Genomics (UMR 5203 CNRS-U 1191 INSERM), Montpellier, France
| | - Federica Bertaso
- Laboratory of Pathophysiology of Synaptic Transmission, Institute of Functional Genomics (UMR 5203 CNRS-U 1191 INSERM), Montpellier, France
| | - Nicola Marchi
- Laboratory of Cerebrovascular Mechanisms of Brain Disorders, Institute of Functional Genomics (UMR 5203 CNRS-U 1191 INSERM), Montpellier, France
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Weiss N, Rosselli M, Mouri S, Galanaud D, Puybasset L, Agarwal B, Thabut D, Jalan R. Modification in CSF specific gravity in acutely decompensated cirrhosis and acute on chronic liver failure independent of encephalopathy, evidences for an early blood-CSF barrier dysfunction in cirrhosis. Metab Brain Dis 2017; 32:369-376. [PMID: 27730496 DOI: 10.1007/s11011-016-9916-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 09/23/2016] [Indexed: 12/30/2022]
Abstract
Although hepatic encephalopathy (HE) on the background of acute on chronic liver failure (ACLF) is associated with high mortality rates, it is unknown whether this is due to increased blood-brain barrier permeability. Specific gravity of cerebrospinal fluid measured by CT is able to estimate blood-cerebrospinal fluid-barrier permeability. This study aimed to assess cerebrospinal fluid specific gravity in acutely decompensated cirrhosis and to compare it in patients with or without ACLF and with or without hepatic encephalopathy. We identified all the patients admitted for acute decompensation of cirrhosis who underwent a brain CT-scan. Those patients could present acute decompensation with or without ACLF. The presence of hepatic encephalopathy was noted. They were compared to a group of stable cirrhotic patients and healthy controls. Quantitative brain CT analysis used the Brainview software that gives the weight, the volume and the specific gravity of each determined brain regions. Results are given as median and interquartile ranges and as relative variation compared to the control/baseline group. 36 patients presented an acute decompensation of cirrhosis. Among them, 25 presented with ACLF and 11 without ACLF; 20 presented with hepatic encephalopathy grade ≥ 2. They were compared to 31 stable cirrhosis patients and 61 healthy controls. Cirrhotic patients had increased cerebrospinal fluid specific gravity (CSF-SG) compared to healthy controls (+0.4 %, p < 0.0001). Cirrhotic patients with ACLF have decreased CSF-SG as compared to cirrhotic patients without ACLF (-0.2 %, p = 0.0030) that remained higher than in healthy controls. The presence of hepatic encephalopathy did not modify CSF-SG (-0.09 %, p = 0.1757). Specific gravity did not differ between different brain regions according to the presence or absence of either ACLF or HE. In patients with acute decompensation of cirrhosis, and those with ACLF, CSF specific gravity is modified compared to both stable cirrhotic patients and healthy controls. This pattern is observed even in the absence of hepatic encephalopathy suggesting that blood-CSF barrier impairment is manifest even in absence of overt hepatic encephalopathy.
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Affiliation(s)
- Nicolas Weiss
- Brain-Liver Pitié-Salpêtrière Study Group (BLIPS), Hôpital de la Pitié Salpétrière, and INSERM UMR_S 938, CDR Saint-Antoine, Assistance Publique-Hôpitaux de Paris, Paris, France.
- Unité de réanimation neurologique, Fédération de Neurologie, Pôle des maladies du système nerveux, Hôpital de la Pitié Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.
- Institut de Neurosciences Translationnelles de Paris, Institut-Hospitalo-Universitaire-A-Institut du Cerveau et de la Moelle (IHU-A-ICM), Paris, France.
| | - Matteo Rosselli
- Liver Failure Group, UCL Institute for Liver and Digestive Health, UCL Medical School, Royal Free Hospital, London, UK
| | - Sarah Mouri
- Brain-Liver Pitié-Salpêtrière Study Group (BLIPS), Hôpital de la Pitié Salpétrière, and INSERM UMR_S 938, CDR Saint-Antoine, Assistance Publique-Hôpitaux de Paris, Paris, France
- Soins Intensifs d'Hépatologie, Service d'Hépato-Gastroentérologie, Hôpital de la Pitié Salpétrière, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Damien Galanaud
- Service de Neuroradiologie, Hôpital de la Pitié-Salpêtrière, Assistance Publique - Hôpitaux de Paris, Paris, France
| | - Louis Puybasset
- Neuro-réanimation chirurgicale, département d'anesthésie-réanimation, Hôpital de la Pitié-Salpêtrière, Assistance Publique - Hôpitaux de Paris, France and Université Pierre et Marie Curie, Paris, France
| | - Banwari Agarwal
- Liver Failure Group, UCL Institute for Liver and Digestive Health, UCL Medical School, Royal Free Hospital, London, UK
| | - Dominique Thabut
- Brain-Liver Pitié-Salpêtrière Study Group (BLIPS), Hôpital de la Pitié Salpétrière, and INSERM UMR_S 938, CDR Saint-Antoine, Assistance Publique-Hôpitaux de Paris, Paris, France
- Soins Intensifs d'Hépatologie, Service d'Hépato-Gastroentérologie, Hôpital de la Pitié Salpétrière, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Rajiv Jalan
- Liver Failure Group, UCL Institute for Liver and Digestive Health, UCL Medical School, Royal Free Hospital, London, UK
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10
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Benarroch EE. Choroid plexus--CSF system: Recent developments and clinical correlations. Neurology 2015; 86:286-96. [PMID: 26683646 DOI: 10.1212/wnl.0000000000002298] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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11
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Bolos M, Antequera D, Aldudo J, Kristen H, Bullido MJ, Carro E. Choroid plexus implants rescue Alzheimer's disease-like pathologies by modulating amyloid-β degradation. Cell Mol Life Sci 2014; 71:2947-55. [PMID: 24343520 PMCID: PMC11113864 DOI: 10.1007/s00018-013-1529-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 09/13/2013] [Accepted: 11/19/2013] [Indexed: 12/31/2022]
Abstract
The choroid plexuses (CP) release numerous biologically active enzymes and neurotrophic factors, and contain a subpopulation of neural progenitor cells providing the capacity to proliferate and differentiate into other types of cells. These characteristics make CP epithelial cells (CPECs) excellent candidates for cell therapy aiming at restoring brain tissue in neurodegenerative illnesses, including Alzheimer's disease (AD). In the present study, using in vitro approaches, we demonstrated that CP were able to diminish amyloid-β (Aβ) levels in cell cultures, reducing Aβ-induced neurotoxicity. For in vivo studies, CPECs were transplanted into the brain of the APP/PS1 murine model of AD that exhibits advanced Aβ accumulation and memory impairment. Brain examination after cell implantation revealed a significant reduction in brain Aβ deposits, hyperphosphorylation of tau, and astrocytic reactivity. Remarkably, the transplantation of CPECs was accompanied by a total behavioral recovery in APP/PS1 mice, improving spatial and non-spatial memory. These findings reinforce the neuroprotective potential of CPECs and the use of cell therapies as useful tools in AD.
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Affiliation(s)
- Marta Bolos
- Neuroscience Group, Instituto de Investigacion Hospital 12 de Octubre (i+12), Av. de Córdoba s/n, 28041 Madrid, Spain
- Center for Networker Biomedical Research in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Desireé Antequera
- Neuroscience Group, Instituto de Investigacion Hospital 12 de Octubre (i+12), Av. de Córdoba s/n, 28041 Madrid, Spain
- Center for Networker Biomedical Research in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Jesús Aldudo
- Center for Networker Biomedical Research in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Centro de Biología Molecular Severo Ochoa, CBM (UAM/CSIC), Madrid, Spain
| | - Henrike Kristen
- Centro de Biología Molecular Severo Ochoa, CBM (UAM/CSIC), Madrid, Spain
| | - María Jesús Bullido
- Center for Networker Biomedical Research in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Centro de Biología Molecular Severo Ochoa, CBM (UAM/CSIC), Madrid, Spain
| | - Eva Carro
- Neuroscience Group, Instituto de Investigacion Hospital 12 de Octubre (i+12), Av. de Córdoba s/n, 28041 Madrid, Spain
- Center for Networker Biomedical Research in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
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12
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Miller F, Lécuyer H, Join-Lambert O, Bourdoulous S, Marullo S, Nassif X, Coureuil M. Neisseria meningitidis colonization of the brain endothelium and cerebrospinal fluid invasion. Cell Microbiol 2012. [PMID: 23189983 DOI: 10.1111/cmi.12082] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The brain and meningeal spaces are protected from bacterial invasion by the blood-brain barrier, formed by specialized endothelial cells and tight intercellular junctional complexes. However, once in the bloodstream, Neisseria meningitidis crosses this barrier in about 60% of the cases. This highlights the particular efficacy with which N. meningitidis targets the brain vascular cell wall. The first step of central nervous system invasion is the direct interaction between bacteria and endothelial cells. This step is mediated by the type IV pili, which induce a remodelling of the endothelial monolayer, leading to the opening of the intercellular space. In this review, strategies used by the bacteria to survive in the bloodstream, to colonize the brain vasculature and to cross the blood-brain barrier will be discussed.
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Affiliation(s)
- Florence Miller
- INSERM, unité U1002, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Faculté de médecine, Paris, France
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13
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Ho HTB, Dahlin A, Wang J. Expression Profiling of Solute Carrier Gene Families at the Blood-CSF Barrier. Front Pharmacol 2012; 3:154. [PMID: 22936914 PMCID: PMC3426838 DOI: 10.3389/fphar.2012.00154] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 08/01/2012] [Indexed: 12/12/2022] Open
Abstract
The choroid plexus (CP) is a highly vascularized tissue in the brain ventricles and acts as the blood-cerebrospinal fluid (CSF) barrier (BCSFB). A main function of the CP is to secrete CSF, which is accomplished by active transport of small ions and water from the blood side to the CSF side. The CP also supplies the brain with certain nutrients, hormones, and metal ions, while removing metabolites and xenobiotics from the CSF. Numerous membrane transporters are expressed in the CP in order to facilitate the solute exchange between the blood and the CSF. The solute carrier (SLC) superfamily represents a major class of transporters in the CP that constitutes the molecular mechanisms for CP function. Recently, we systematically and quantitatively examined Slc gene expression in 20 anatomically comprehensive brain areas in the adult mouse brain using high-quality in situ hybridization data generated by the Allen Brain Atlas. Here we focus our analysis on Slc gene expression at the BCSFB using previously obtained data. Of the 252 Slc genes present in the mouse brain, 202 Slc genes were found at detectable levels in the CP. Unsupervised hierarchical cluster analysis showed that the CP Slc gene expression pattern is substantially different from the other 19 analyzed brain regions. The majority of the Slc genes in the CP are expressed at low to moderate levels, whereas 28 Slc genes are present in the CP at the highest levels. These highly expressed Slc genes encode transporters involved in CSF secretion, energy production, and transport of nutrients, hormones, neurotransmitters, sulfate, and metal ions. In this review, the functional characteristics and potential importance of these Slc transporters in the CP are discussed, with particular emphasis on their localization and physiological functions at the BCSFB.
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Affiliation(s)
- Horace T B Ho
- Department of Pharmaceutics, University of Washington Seattle, WA, USA
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14
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A novel porcine in vitro model of the blood-cerebrospinal fluid barrier with strong barrier function. PLoS One 2012; 7:e39835. [PMID: 22745832 PMCID: PMC3382175 DOI: 10.1371/journal.pone.0039835] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 05/27/2012] [Indexed: 01/10/2023] Open
Abstract
Epithelial cells of the plexus choroideus form the structural basis of the blood-cerebrospinal fluid barrier (BCSFB). In vitro models of the BCSFB presenting characteristics of a functional barrier are of significant scientific interest as tools for examination of BCSFB function. Due to a lack of suitable cell lines as in vitro models, primary porcine plexus epithelial cells were subjected to a series of selective cultivation steps until a stable continuous subcultivatable epithelial cell line (PCP-R) was established. PCP-R cells grow in a regular polygonal pattern with a doubling time of 28–36 h. At a cell number of 1.5×105 in a 24-well plate confluence is reached in 56–72 h. Cells are cytokeratin positive and chromosomal analysis revealed 56 chromosomes at peak (84th subculture). Employing reverse transcription PCR mRNA expression of several transporters and components of cell junctions could be detected. The latter includes tight junction components like Claudin-1 and -3, ZO-1, and Occludin, and the adherens junction protein E-cadherin. Cellular localization studies of ZO-1, Occludin and Claudin-1 by immunofluorescence and morphological analysis by electron microscopy demonstrated formation of a dense tight junction structure. Importantly, when grown on cell culture inserts PCP-R developed typical characteristics of a functional BCSFB including high transepithelial electrical resistance above 600 Ω×cm2 as well as low permeability for macromolecules. In summary, our data suggest the PCP-R cell line as a suitable in vitro model of the porcine BCSFB.
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15
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Kumari R, Lakhan R, Garg RK, Kalita J, Misra UK, Mittal B. Pharmacogenomic association study on the role of drug metabolizing, drug transporters and drug target gene polymorphisms in drug-resistant epilepsy in a north Indian population. INDIAN JOURNAL OF HUMAN GENETICS 2011; 17 Suppl 1:S32-40. [PMID: 21747585 PMCID: PMC3125053 DOI: 10.4103/0971-6866.80357] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND: In epilepsy, in spite of the best possible medications and treatment protocols, approximately one-third of the patients do not respond adequately to anti-epileptic drugs. Such interindividual variations in drug response are believed to result from genetic variations in candidate genes belonging to multiple pathways. MATERIALS AND METHODS: In the present pharmacogenetic analysis, a total of 402 epilepsy patients were enrolled. Of them, 128 were diagnosed as multiple drug-resistant epilepsy and 274 patients were diagnosed as having drug-responsive epilepsy. We selected a total of 10 candidate gene polymorphisms belonging to three major classes, namely drug transporters, drug metabolizers and drug targets. These genetic polymorphism included CYP2C9 c.430C>T (*2 variant), CYP2C9 c.1075 A>C (*3 variant), ABCB1 c.3435C>T, ABCB1c.1236C>T, ABCB1c.2677G>T/A, SCN1A c.3184 A> G, SCN2A c.56G>A (p.R19K), GABRA1c.IVS11 + 15 A>G and GABRG2 c.588C>T. Genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods, and each genotype was confirmed via direct DNA sequencing. The relationship between various genetic polymorphisms and responsiveness was examined using binary logistic regression by SPSS statistical analysis software. RESULTS: CYP2C9 c.1075 A>C polymorphism showed a marginal significant difference between drug resistance and drug-responsive patients for the AC genotype (Odds ratio [OR] = 0.57, 95% confidence interval [CI] = 0.32–1.00; P = 0.05). In drug transporter, ABCB1c.2677G>T/A polymorphism, allele A was associated with drug-resistant phenotype in epilepsy patients (P = 0.03, OR = 0.31, 95% CI = 0.10-0.93). Similarly, the variant allele frequency of SCN2A c.56 G>A single nucleotide polymorphism was significantly higher in drug-resistant patients (P = 0.03; OR = 1.62, 95% CI = 1.03, 2.56). We also observed a significant difference at the genotype as well as allele frequencies of GABRA1c.IVS11 + 15 A > G polymorphism in drug-resistant patients for homozygous GG genotype (P = 0.03, OR = 1.84, 95% CI = 1.05–3.23) and G allele (P = 0.02, OR = 1.43, 95% CI = 1.05–1.95). CONCLUSIONS: Our results showed that pharmacogenetic variants have important roles in epilepsy at different levels. It may be noted that multi-factorial diseases like epilepsy are also regulated by various other factors that may also be considered in the future.
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Affiliation(s)
- Ritu Kumari
- Department of Genetics, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
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16
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Baird A, Eliceiri BP, Gonzalez AM, Johanson CE, Leadbeater W, Stopa EG. Targeting the choroid plexus-CSF-brain nexus using peptides identified by phage display. Methods Mol Biol 2011; 686:483-98. [PMID: 21082389 DOI: 10.1007/978-1-60761-938-3_25] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Drug delivery to the central nervous system requires the use of specific portals to enable drug entry into the brain and, as such, there is a growing need to identify processes that can enable drug transfer across both blood-brain and blood-cerebrospinal fluid barriers. Phage display is a powerful combinatorial technique that identifies specific peptides that can confer new activities to inactive particles. Identification of these peptides is directly dependent on the specific screening strategies used for their selection and retrieval. This chapter describes three selection strategies, which can be used to identify peptides that target the choroid plexus (CP) directly or for drug translocation across the CP and into cerebrospinal fluid.
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Affiliation(s)
- Andrew Baird
- Department of Surgery, Division of Trauma, Burns and Critical Care, University of California San Diego, San Diego, CA, USA
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17
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Menheniott TR, Charalambous M, Ward A. Derivation of primary choroid plexus epithelial cells from the mouse. Methods Mol Biol 2010; 633:207-20. [PMID: 20204630 DOI: 10.1007/978-1-59745-019-5_15] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Choroid plexus epithelial cells form an integral and important part of the barrier between blood and cerebrospinal fluid. Culture of choroid plexus epithelium in vitro has been achieved from several mammalian species and this provides opportunities for the study of choroid plexus development and function, including the capacity of the epithelial cells to control the movement of bioactive molecules, such as novel drug candidates, from the bloodstream to the brain. Here we describe a method for the derivation of primary cell cultures from mouse choroid plexus epithelium, together with characterisation by immunofluorescence using antibodies specific to markers of mature choroid plexus epithelial cells. With this method, relatively pure choroid plexus epithelial cell monolayers are established using the DNA synthesis inhibitor cytosine arabinoside (Ara-C), which is cytotoxic to contaminating cell types such as fibroblasts, but not the epithelial cells. These cells are shown to express the diagnostic choroidal marker, transthyretin (TTR), as well as markers of epithelial cell differentiation and are thus suitable for studies that address the transport and barrier functions of the choroid plexus.
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Affiliation(s)
- Trevelyan R Menheniott
- Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC 3052, Australia
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18
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Thiéry JC, Lomet D, Bougoin S, Malpaux B. Turnover rate of cerebrospinal fluid in female sheep: changes related to different light-dark cycles. Cerebrospinal Fluid Res 2009; 6:9. [PMID: 19653900 PMCID: PMC2731051 DOI: 10.1186/1743-8454-6-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Accepted: 08/04/2009] [Indexed: 04/18/2024] Open
Abstract
BACKGROUND Sheep are seasonal breeders. The key factor governing seasonal changes in the reproductive activity of the ewe is increased negative feedback of estradiol at the level of the hypothalamus under long-day conditions. It has previously been demonstrated that when gonadotropin secretions are inhibited during long days, there is a higher concentration of estradiol in the cerebrospinal fluid (CSF) than during short days. This suggests an involvement of the CSF and choroid plexus in the neuroendocrine regulatory loop, but the mechanisms underlying this phenomenon remain unknown. One possible explanation of this difference in hormonal content is an effect of concentration or dilution caused by variations in CSF secretion rate. The aim of this study was thus to investigate changes in the CSF turnover rate related to light-dark cycles. METHODS The turnover rate of the CSF was estimated by measuring the time taken for the recovery of intraventricular pressure (IVP) after removal of a moderate volume (0.5 to 2 ml) of CSF (slope in mmHg/min). The turnover rate was estimated three times in the same group of sheep: during a natural period of decreasing day-length corresponding to the initial period when gonadotropin activity is stimulated (SG1), during a long-day inhibitory period (IG), and finally during a short-day stimulatory period (SG2). RESULTS The time taken and the speed of recovery of initial IVP differed between groups: 8 min 30 sec, 0.63 +/- 0.07 mmHg/min(SG1), 11 min 1 sec, 0.38 +/- 0.06 mmHg/min (IG) and 9 min 0 sec, 0.72 +/- 0.15 mmHg/min (SG2). Time changes of IVP differed between groups (ANOVA, p < 0.005, SG1 different from IG, p < 0.05). The turnover rate in SG2: 183.16 +/- 23.82 mul/min was not significantly different from SG1: 169. 23 +/- 51.58 mul/min (Mann-Whitney test, p = 0.41), but was significantly different from IG: 71.33 +/- 16.59 mul/min (p = 0.016). CONCLUSION This study shows that the turnover rate of CSF in ewes changes according to the light-dark cycle; it is increased during short day periods and reduced in long day periods. This phenomenon could account for differences in hormonal concentrations in the CSF in this seasonal species.
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Affiliation(s)
- Jean-Claude Thiéry
- UMR: INRA – CNRS – Université François Rabelais de Tours – Haras nationaux 37380 Nouzilly, France
| | - Didier Lomet
- UMR: INRA – CNRS – Université François Rabelais de Tours – Haras nationaux 37380 Nouzilly, France
| | - Sylvain Bougoin
- UMR: INRA – CNRS – Université François Rabelais de Tours – Haras nationaux 37380 Nouzilly, France
| | - Benoit Malpaux
- UMR: INRA – CNRS – Université François Rabelais de Tours – Haras nationaux 37380 Nouzilly, France
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19
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Abstract
Drug transporters are membrane proteins present in various tissues such as the lymphocytes, intestine, liver, kidney, testis, placenta, and central nervous system. These transporters play a significant role in drug absorption and distribution to organic systems, particularly if the organs are protected by blood-organ barriers, such as the blood-brain barrier or the maternal-fetal barrier. In contrast to neurotransmitters and receptor-coupled transporters or other modes of interneuronal transmission, drug transporters are not directly involved in specific neuronal functions, but provide global protection to the central nervous system. The lack of capillary fenestration, the low pinocytic activity, and the tight junctions between brain capillary and choroid plexus endothelial cells represent further gatekeepers limiting the entrance of endogenous and exogenous compounds into the central nervous system. Drug transport is a result of the concerted action of efflux and influx pumps (transporters) located both in the basolateral and apical membranes of brain capillary and choroid plexus endothelial cells. By regulating efflux and influx of endogenous or exogenous substances, the blood-brain barrier and, to a lesser extent, the blood-cerebrospinal barrier in the ventricles, represents the main interface between the central nervous system and the blood, ie, the rest of the body. As drug distribution to organs is dependent on the affinity of a substrate for a specific transport system, membrane transporter proteins are increasingly recognized as a key determinant of drug disposition. Many drug transporters are members of the adenosine triphosphate (ATP)-binding cassette (ABC) transporter superfamily or the solute-linked carrier (SLC) class. The multidrug resistance protein MDR1 (ABCB1), also called P-glycoprotein, the multidrug resistance-associated proteins MRP1 (ABCC1) and MRP2 (ABCC2), and the breast cancer-resistance protein BCRP (ABCG2) are ATP-dependent efflux transporters expressed in the blood-brain barrier. They belong to the superfamily of ABC transporters, which export drugs from the intracellular to the extracellular milieu. Members of the SLC class of solute carriers include, for example, organic ion transporting peptides, organic cation transporters, and organic ion transporters. They are ATP-independent polypeptides principally expressed at the basolateral membrane of brain capillary and choroid plexus endothelial cells that also mediate drug transport through central nervous system barriers.
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Affiliation(s)
- François Girardin
- Unit of Clinical Psychopharmacology, Geneva University Hospitals, Chênes-Bourg, Geneva, Switzerland.
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20
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Baehr CH, Fricker G, Miller DS. Fluorescein-methotrexate transport in dogfish shark (Squalus acanthias) choroid plexus. Am J Physiol Regul Integr Comp Physiol 2006; 291:R464-72. [PMID: 16914433 DOI: 10.1152/ajpregu.00814.2005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The vertebrate choroid plexus removes potentially toxic metabolites and xenobiotics from cerebrospinal fluid (CSF) to blood for subsequent excretion in urine and bile. We used confocal microscopy and quantitative image analysis to characterize the mechanisms driving transport of the large organic anion, fluorescein-methotrexate (FL-MTX), from bath (CSF-side) to blood vessels in intact lateral choroid plexus from dogfish shark, Squalus acanthias, an evolutionarily ancient vertebrate. With 2 μM FL-MTX in the bath, steady-state fluorescence in the subepithelium/vascular space exceeded bath levels by 5- to 10-fold, and fluorescence in the epithelial cells was slightly below bath levels. FL-MTX accumulation in both tissue compartments was reduced by NaCN, Na removal, and ouabain, but not by a 10-fold increase in medium K. Certain organic anions, e.g., probenecid, MTX, and taurocholate, reduced FL-MTX accumulation in both tissue compartments; p-aminohippurate and estrone sulfate reduced subepithelial/vascular accumulation, but not cellular accumulation. At low concentrations, digoxin, leukotriene C4, and MK-571 reduced fluorescence in the subepithelium/vascular space while increasing cellular fluorescence, indicating preferential inhibition of efflux over uptake. In the presence of 10 μM digoxin (reduced efflux, enhanced cellular accumulation), cellular FL-MTX accumulation was specific, concentrative, and Na dependent. Thus transepithelial FL-MTX transport involved the following two carrier-mediated steps: electroneutral, Na-dependent uptake at the apical membrane and electroneutral efflux at the basolateral membrane. Finally, FL-MTX accumulation in both tissue compartments was reduced by phorbol ester and increased by forskolin, indicating antagonistic modulation by protein kinase C and protein kinase A.
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Affiliation(s)
- Carsten H Baehr
- Institute for Pharmacy and Molecular Biotechnology, University of Heidelberg, Germany
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21
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Dallas S, Miller DS, Bendayan R. Multidrug Resistance-Associated Proteins: Expression and Function in the Central Nervous System. Pharmacol Rev 2006; 58:140-61. [PMID: 16714484 DOI: 10.1124/pr.58.2.3] [Citation(s) in RCA: 230] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Drug delivery to the brain is highly restricted, since compounds must cross a series of structural and metabolic barriers to reach their final destination, often a cellular compartment such as neurons, microglia, or astrocytes. The primary barriers to the central nervous system are the blood-brain and blood-cerebrospinal fluid barriers. Through structural modifications, including the presence of tight junctions that greatly limit paracellular transport, the cells that make up these barriers restrict diffusion of many pharmaceutically active compounds. In addition, the cells that comprise the blood-brain and blood-cerebrospinal fluid barriers express multiple ATP-dependent, membrane-bound, efflux transporters, such as members of the multidrug resistance-associated protein (MRP) family, which contribute to lowered drug accumulation. A relatively new concept in brain drug distribution just beginning to be explored is the possibility that cellular components of the brain parenchyma could act as a "second" barrier to brain permeation of pharmacological agents via expression of many of the same transporters. Indeed, efflux transporters expressed in brain parenchyma may facilitate the overall export of xenobiotics from the central nervous system, essentially handing them off to the barrier tissues. We propose that these primary and secondary barriers work in tandem to limit overall accumulation and distribution of xenobiotics in the central nervous system. The present review summarizes recent knowledge in this area and emphasizes the clinical significance of MRP transporter expression in a variety of neurological disorders.
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Affiliation(s)
- Shannon Dallas
- Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, USA
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22
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Maines LW, Antonetti DA, Wolpert EB, Smith CD. Evaluation of the role of P-glycoprotein in the uptake of paroxetine, clozapine, phenytoin and carbamazapine by bovine retinal endothelial cells. Neuropharmacology 2005; 49:610-7. [PMID: 15961125 DOI: 10.1016/j.neuropharm.2005.04.028] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2005] [Revised: 04/06/2005] [Accepted: 04/15/2005] [Indexed: 01/16/2023]
Abstract
Expression of the drug transport proteins, including P-glycoprotein (Pgp), in the brain vascular endothelium represents a challenge for the effective delivery of drugs for the treatment of several central nervous system (CNS) disorders including depression, schizophrenia and epilepsy. It has been hypothesized that Pgp plays a major role in drug efflux at the blood-brain barrier, and may be an underlying factor in the variable responses of patients to CNS drugs. However, the role of Pgp in the transport of many CNS drugs has not been directly demonstrated. To explore the role of Pgp in drug transport across an endothelial cell barrier derived from the central nervous system, the expression and activity of Pgp in bovine retinal endothelial cells (BRECs) and the effects of representative CNS drugs on Pgp activity were examined. Significant Pgp expression in BRECs was demonstrated by western analyses, and expression was increased by treatment of the cells with hydrocortisone. Intracellular accumulation of the well-characterized Pgp-substrate Taxol was markedly increased by the non-selective transporter inhibitor verapamil and the Pgp-selective antagonist PGP-4008, demonstrating that Pgp is active in these endothelial cells. In contrast, neither verapamil nor PGP-4008 affected the intracellular accumulation of [3H]paroxetine, [14C]phenytoin, [3H]clozapine or [14C]carbamazapine, indicating that these drugs are not substrates for Pgp. Paroxetine, clozapine and phenytoin were shown to be Pgp inhibitors, while carbamazapine did not inhibit Pgp at any concentration tested. These results indicate that Pgp is not likely to modulate patient responses to these drugs.
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Affiliation(s)
- Lynn W Maines
- Department of Pharmacology, The Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
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23
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Ferraro TN, Buono RJ. The relationship between the pharmacology of antiepileptic drugs and human gene variation: an overview. Epilepsy Behav 2005; 7:18-36. [PMID: 15979945 DOI: 10.1016/j.yebeh.2005.04.010] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2005] [Accepted: 04/20/2005] [Indexed: 10/25/2022]
Abstract
Individual differences in clinical responsiveness to antiepileptic drugs are due to a complex interaction between environmental factors and genetic variation. Considerable interest has arisen in exploiting advances in molecular genetics to improve drug therapy for epilepsy and many other diseases; however, practical application of pharmacogenetics has been difficult to realize. Attempts to define gene variants that are associated with therapeutic (or adverse) effects of antiepileptic drugs rely currently on the prior identification of candidate genes and the subsequent evaluation of the distribution of allelic variants between individuals who have a "good" versus a "poor" clinical response. Many factors can adversely affect interpretation of such data, and careful consideration must be given to the design of genetic association studies involving candidate genes. Candidate genes may be identified in a number of ways; however, for studies of drugs, application of knowledge derived from basic pharmacology can suggest focused and testable hypotheses that are based on the fundamental principles of drug action. Thus, studies of genetic variation as they relate to proteins involved in antiepileptic drug kinetics and dynamics will identify key polymorphisms in endogenous molecules that determine degrees of drug efficacy and toxicity. Delineation of these effects in the coming years will promote enhanced success in the treatment of epilepsy.
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Affiliation(s)
- Thomas N Ferraro
- Departments of Psychiatry and Pharmacology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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24
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Lowes S, Sykes D, Breen CM, Ragone LJ, Miller DS. Multiple Components of 2,4-Dichlorophenoxyacetic Acid Uptake by Rat Choroid Plexus. J Pharmacol Exp Ther 2005; 315:136-43. [PMID: 15958719 DOI: 10.1124/jpet.105.087056] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Initial rates of uptake of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D; 20 microM) were measured in intact lateral choroid plexus from rat. Although inhibition of uptake by millimolar concentrations of estrone sulfate (ES) and unlabeled 2,4-D was maximal at 85%, inhibition by p-aminohippurate (PAH) saturated at about 50%. Inhibition by ES plus PAH was no greater than by ES or 2,4-D alone. Thus, inhibition studies indicated three distinct components of uptake; two mediated and one not. The sodium-dependent component of 2,4-D uptake coincided with the PAH-sensitive component, indicating uptake mediated by organic anion transporter subtype (Oat) 3. Consistent with this, efflux of 2,4-D from preloaded tissue was accelerated by all Oat3 substrates tested, and 2,4-D increased the efflux of the Oat3 substrate, PAH. Consistent with the inhibition data, kinetic analysis showed three components of 2,4-D uptake: a nonmediated component (linear kinetics), a high-affinity component, and a low-affinity component. The high-affinity component appeared to coincide with the PAH-sensitive and sodium-dependent component characterized in inhibition studies. The PAH-insensitive, low-affinity component was inhibited by ES, dehydroepiandrosterone sulfate, and taurocholate but not by 5-hydroxyindole acetic acid. Thus, the first step in transport of 2,4-D from cerebrospinal fluid to blood involves two transporters: Oat3 and a PAH-insensitive, sodium-independent transporter. Based on inhibitor profile, the latter may be Oatp3.
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Affiliation(s)
- Simon Lowes
- Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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25
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Löscher W, Potschka H. Role of drug efflux transporters in the brain for drug disposition and treatment of brain diseases. Prog Neurobiol 2005; 76:22-76. [PMID: 16011870 DOI: 10.1016/j.pneurobio.2005.04.006] [Citation(s) in RCA: 411] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2004] [Revised: 03/23/2005] [Accepted: 04/26/2005] [Indexed: 01/01/2023]
Abstract
The blood-brain barrier (BBB) serves as a protective mechanism for the brain by preventing entry of potentially harmful substances from free access to the central nervous system (CNS). Tight junctions present between the brain microvessel endothelial cells form a diffusion barrier, which selectively excludes most blood-borne substances from entering the brain. Astrocytic end-feet tightly ensheath the vessel wall and appear to be critical for the induction and maintenance of the barrier properties of the brain capillary endothelial cells. Because of these properties, the BBB only allows entry of lipophilic compounds with low molecular weights by passive diffusion. However, many lipophilic drugs show negligible brain uptake. They are substrates for drug efflux transporters such as P-glycoprotein (Pgp), multidrug resistance proteins (MRPs) or organic anion transporting polypeptides (OATPs) that are expressed at brain capillary endothelial cells and/or astrocytic end-feet and are key elements of the molecular machinery that confers the special permeability properties to the BBB. The combined action of these carrier systems results in rapid efflux of xenobiotics from the CNS. The objective of this review is to summarize transporter characteristics (cellular localization, specificity, regulation, and potential inhibition) for drug efflux transport systems identified in the BBB and blood-cerebrospinal fluid (CSF) barrier. A variety of experimental approaches available to ascertain or predict the impact of efflux transport on brain access of therapeutic drugs also are described and critically discussed. The potential impact of efflux transport on the pharmacodynamics of agents acting in the CNS is illustrated. Furthermore, the current knowledge about drug efflux transporters as a major determinant of multidrug resistance of brain diseases such as epilepsy is reviewed. Finally, we summarize strategies for modulating or by-passing drug efflux transporters at the BBB as novel therapeutic approaches to drug-resistant brain diseases.
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Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, D-30559 Hannover, Germany
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Nagata Y, Kusuhara H, Imaoka T, Endou H, Sugiyama Y. Involvement of Rat Organic Anion Transporter 3 in the Uptake of an Organic Herbicide, 2,4-Dichlorophenoxyacetate, by the isOlated Rat Choroid Plexus. J Pharm Sci 2004; 93:2724-32. [PMID: 15389674 DOI: 10.1002/jps.20175] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
2,4-Dichlorophenoxyacetic acid (2,4-D) is an anionic herbicide. The purpose of the present study is to examine whether organic anion transporter 3 (Oat3; Slc22a8) is solely responsible for the uptake of 2,4-D by the isolated rat choroid plexus (CP). When expressed in LLC-PK1 cells, rOat3 was mainly localized to the basolateral membrane. Although there was no vectorial transport of 2,4-D in the control LLC-PK1 cells, expression of rOat3 increased the basal-to-apical transport of 2,4-D fourfold without affecting the transcellular transport in the opposite direction. The basal-to-apical transport of 2,4-D in rOat3-LLC was saturable with a K(m) value of 20 microM. The uptake of 2,4-D by the isolated rat CP was determined using the centrifugal filtration method. Saturable uptake of 2,4-D was observed in the isolated rat CP with a K(m) value of 22 microM. Probenecid and substrates of rOat3, such as p-aminohippurate, benzylpenicillin, and cimetidine, inhibited the uptake of 2,4-D by the isolated rat CP. Their K(i) values were comparable with those for the uptake of benzylpenicillin by the isolated rat CP, which is mainly mediated by rOat3. Furthermore, benzylpenicillin was a competitive inhibitor for the uptake of 2,4-D by the isolated rat CP. These results suggest that 2,4-D and benzylpenicillin share the same transporter for their uptake by the isolated rat CP, and rOat3 is the most likely candidate transporter.
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Affiliation(s)
- Yoshinori Nagata
- Graduate school of Pharmaceutical Sciences, the University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Breen CM, Sykes DB, Baehr C, Fricker G, Miller DS. Fluorescein-methotrexate transport in rat choroid plexus analyzed using confocal microscopy. Am J Physiol Renal Physiol 2004; 287:F562-9. [PMID: 15126245 DOI: 10.1152/ajprenal.00045.2003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
One function of the vertebrate choroid plexus (CP) is removal of potentially toxic metabolites and xenobiotics from cerebrospinal fluid (CSF) to blood for subsequent excretion in urine and bile. We have used confocal microscopy and quantitative image analysis to follow transport of the large organic anion fluorescein-methotrexate (FL-MTX) from bath (CSF side) to blood vessels in intact rat CP and found concentrative transport from CSF to blood. With 2 μM FL-MTX in the bath, steady-state fluorescence in the subepithelium and vascular spaces exceeded bath levels by 5- to 10-fold, but fluorescence in epithelial cells was below bath levels. FL-MTX accumulation in subepithelium and vascular spaces was reduced by NaCN, Na removal, and by other organic anions, e.g., MTX, probenecid, and estrone sulfate. Increasing medium K 10-fold had no effect. None of these treatments affected cellular accumulation. However, two observations indicated that apical FL-MTX uptake was indeed mediated: first, cellular accumulation was a saturable function of medium substrate concentration; and second, digoxin and MK-571 reduced FL-MTX accumulation in the subepithelial/vascular spaces but also increased cellular accumulation severalfold. In the presence of digoxin and MK-571, cellular accumulation was concentrative, specific, and Na dependent. Thus transepithelial FL-MTX transport involved the following two mediated steps: Na-dependent uptake at the apical membrane and electroneutral efflux at the basolateral membrane, possibly on Oatp2 and Mrp1.
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Affiliation(s)
- Christopher M Breen
- Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
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Kurrimbux D, Gaffen Z, Farrell CL, Martin D, Thomas SA. The involvement of the blood–brain and the blood–cerebrospinal fluid barriers in the distribution of leptin into and out of the rat brain. Neuroscience 2004; 123:527-36. [PMID: 14698759 DOI: 10.1016/j.neuroscience.2003.08.061] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Leptin is a 16 kDa hormone that is produced by adipose tissue and has a central effect on food intake and energy homeostasis. The ability of leptin to cross the blood-brain and blood-cerebrospinal fluid (CSF) barriers and reach or leave the CNS was studied by the bilateral in situ brain perfusion and isolated incubated choroid plexus techniques in the rat. Brain perfusion results indicated that [(125)I]leptin reached the CNS at higher concentrations than the vascular marker, confirming that [(125)I]leptin crossed the brain barriers. Leptin distribution varied between CNS regions and indicated that the blood-brain barrier, in contrast to the blood-CSF route, was the key pathway for [(125)I]leptin to reach the brain. Further perfusion studies revealed that [(125)I]leptin movement into the arcuate nucleus, thalamus, frontal cortex, choroid plexuses and CSF was unaffected by unlabelled human or murine leptin at a concentration that reflects the upper human and rat plasma leptin concentration (2.5 nM). In contrast, the cerebellum uptake of [(125)I]leptin was decreased by 73% with 2.5 nM human leptin. Thus, this site of dense leptin receptor expression would be sensitive to physiological changes in leptin plasma concentrations. The highest rate (K(in)) of [(125)I]leptin uptake was into the choroid plexuses (307.7+/-68.0 microl/min/g); however, this was not reflected in the CSF (8.9+/-4.1 microl/min/g) and indicates that this tissue tightly regulates leptin distribution. The multiple-time brain uptake of [(125)I]leptin was non-linear and suggested leptin could also be removed from the CNS. Studies using the incubated rat choroid plexus model found that [(125)I]leptin could cross the apical membrane of the choroid plexus to leave the CSF. However, this movement was not sensitive to unlabelled human leptin or specific transport inhibitors/modulators (including probenecid, digoxin, deltorphin II, progesterone and indomethacin).This study supports the concept of brain-barrier regulation of leptin distribution to the CNS, and highlights an important link between leptin and the cerebellum.
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Affiliation(s)
- D Kurrimbux
- Centre for Neuroscience, Guy's, King's and St. Thomas School of Biomedical Sciences, King's College London, Hodgkin Building, Guy's Hospital Campus, London SE1 1UL, UK
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Sykes D, Sweet DH, Lowes S, Nigam SK, Pritchard JB, Miller DS. Organic anion transport in choroid plexus from wild-type and organic anion transporter 3 (Slc22a8)-null mice. Am J Physiol Renal Physiol 2003; 286:F972-8. [PMID: 15075193 DOI: 10.1152/ajprenal.00356.2003] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The choroid plexus actively transports endogenous, xenobiotic, and therapeutic compounds from cerebrospinal fluid to blood, thereby limiting their exposure to the central nervous system (CNS). Establishing the mechanisms responsible for this transport is critical to our understanding of basic choroid plexus physiology and will likely impact drug targeting to the CNS. We recently generated an organic anion transporter 3- (Oat3)-null mouse, which exhibited loss of PAH, estrone sulfate, and taurocholate transport in kidney and of fluorescein (FL) transport in choroid plexus. Here, we measured the uptake of four Oat3 substrates by choroid plexus from wild-type and Oat3-null mice to establish 1) the contribution of Oat3 to the apical uptake of each substrate and 2) the Na dependence of transport by Oat3 in the intact tissue. Mediated transport of PAH and FL was essentially abolished in tissue from Oat3-null mice. In contrast, only a 33% reduction in estrone sulfate uptake was observed in tissue from Oat3-null mice and, surprisingly, no reduction in taurocholate uptake could be detected. For PAH, FL, and estrone sulfate, all Oat3-mediated transport was Na dependent. However, estrone sulfate and taurocholate also exhibited additional mediated and Na-dependent components of uptake that were not attributed to Oat3, demonstrating the complexity of organic anion transport in this tissue and the need for further examination of expressed transporters and their energetics.
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Affiliation(s)
- Destiny Sykes
- Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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Strazielle N, Khuth ST, Murat A, Chalon A, Giraudon P, Belin MF, Ghersi-Egea JF. Pro-Inflammatory Cytokines Modulate Matrix Metalloproteinase Secretion and Organic Anion Transport at the Blood-Cerebrospinal Fluid Barrier. J Neuropathol Exp Neurol 2003; 62:1254-64. [PMID: 14692701 DOI: 10.1093/jnen/62.12.1254] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Neuroinflammation and neuroinfection trigger cytokine-mediated responses that include an increase in the cerebrospinal fluid (CSF) levels of pro-inflammatory matrix metalloproteinases (MMPs) and organic anions such as leukotrienes and prostaglandins. The choroid plexus (CP) epithelium forming the interface between the blood and the CSF regulates the CSF concentration of bioactive organic anions and is involved in neuro-immune regulation. We demonstrated that both fourth and lateral ventricle CPs are a source of pro- and active MMP-2 and MMP-9 in the brain. Using a cellular model of the blood-CSF barrier, we showed that a pro-inflammatory cytokine treatment leads to an increase in the choroidal MMP secretion at either the apical or the basolateral membrane, depending on the ventricular origin of the choroidal cells. This effect was not concomitant with an alteration in the structural blood-CSF barrier. Neither was the pool of antioxidant sulfhydryls in the choroidal cells challenged. In contrast, the efficiency of the choroidal epithelium to clear the CSF from organic anions was highly reduced. Thus, during inflammation, the CPs could be one source of MMPs found in the CSF facilitate leucocyte migration by secreting MMPs into the choroidal stroma, and promote the inflammatory process by failing in its ability to clear deleterious compounds from the brain.
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Anthonypillai C, Sanderson RN, Gibbs JE, Thomas SA. The Distribution of the HIV Protease Inhibitor, Ritonavir, to the Brain, Cerebrospinal Fluid, and Choroid Plexuses of the Guinea Pig. J Pharmacol Exp Ther 2003; 308:912-20. [PMID: 14634041 DOI: 10.1124/jpet.103.060210] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Anti-human immunodeficiency virus (HIV) drug penetration into the brain and cerebrospinal fluid (CSF) is necessary to tackle HIV within the CNS. This study examines movement of [(3)H]ritonavir across the guinea pig blood-brain and blood-CSF barriers and accumulation within the brain, CSF, and choroid plexus. Ritonavir is a protease inhibitor, used in combination therapy (often as a pharmacoenhancer) to treat HIV. Drug interactions at brain barrier efflux systems may influence the CNS penetration of anti-viral drugs, thus the influence of additional protease inhibitors, nucleoside reverse transcriptase inhibitors, and non-nucleoside reverse transcriptase inhibitors on [(3)H]ritonavir CNS distribution was explored. Additionally, the involvement of transporters on [(3)H]ritonavir passage across the brain barriers was assessed. Results from in situ brain perfusions and capillary depletion analysis demonstrated that [(3)H]ritonavir uptake into the guinea pig brain was considerable (6.6 +/- 0.7 ml/100 g at 30 min, vascular space corrected), although a proportion of drug remained trapped in the cerebral capillaries and did not reach the brain parenchyma. CSF uptake was more limited (2.2 +/- 0.4 ml/100 g at 30 min), but choroid plexus uptake was abundant (176.7 +/- 46.3 ml/100 g at 30 min). [(3)H]Ritonavir brain and CSF uptake was unaffected by neither inhibitors of organic anion transport (probenecid and digoxin) or P-glycoprotein (progesterone), nor by any additional anti-HIV drugs, indicating that brain barrier efflux systems do not significantly limit brain or CSF [(3)H]ritonavir accumulation in this model. [(3)H]Ritonavir uptake into the perfused choroid plexus was significantly reduced by nevirapine and abacavir, additional perfusion studies, and isolated incubated choroid plexus experiments were carried out in an attempt to further characterize the transporter involved.
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Affiliation(s)
- C Anthonypillai
- Centre for Neuroscience, Guy's, King's and St. Thomas' School of Biomedical Science, King's College London, Guy's Hospital Campus, London, UK
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Zheng W, Aschner M, Ghersi-Egea JF. Brain barrier systems: a new frontier in metal neurotoxicological research. Toxicol Appl Pharmacol 2003; 192:1-11. [PMID: 14554098 PMCID: PMC3982148 DOI: 10.1016/s0041-008x(03)00251-5] [Citation(s) in RCA: 314] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The concept of brain barriers or a brain barrier system embraces the blood-brain interface, referred to as the blood-brain barrier, and the blood-cerebrospinal fluid (CSF) interface, referred to as the blood-CSF barrier. These brain barriers protect the CNS against chemical insults, by different complementary mechanisms. Toxic metal molecules can either bypass these mechanisms or be sequestered in and therefore potentially deleterious to brain barriers. Supportive evidence suggests that damage to blood-brain interfaces can lead to chemical-induced neurotoxicities. This review article examines the unique structure, specialization, and function of the brain barrier system, with particular emphasis on its toxicological implications. Typical examples of metal transport and toxicity at the barriers, such as lead (Pb), mercury (Hg), iron (Fe), and manganese (Mn), are discussed in detail with a special focus on the relevance to their toxic neurological consequences. Based on these discussions, the emerging research needs, such as construction of the new concept of blood-brain regional barriers, understanding of chemical effect on aged or immature barriers, and elucidation of the susceptibility of tight junctions to toxicants, are identified and addressed in this newly evolving field of neurotoxicology. They represent both clear challenges and fruitful research domains not only in neurotoxicology, but also in neurophysiology and pharmacology.
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Affiliation(s)
- Wei Zheng
- School of Health Sciences, Purdue University, West Lafayette, IN 47907, USA.
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Gibbs JE, Rashid T, Thomas SA. Effect of transport inhibitors and additional anti-HIV drugs on the movement of lamivudine (3TC) across the guinea pig brain barriers. J Pharmacol Exp Ther 2003; 306:1035-41. [PMID: 12766261 DOI: 10.1124/jpet.103.053827] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To treat human immunodeficiency virus (HIV) within the central nervous system (CNS), levels of anti-HIV drugs in the brain must reach therapeutic concentrations. The ability of (-)-2'-deoxy-3'-thiacytidine (3TC; lamivudine) to cross the blood-brain and blood-cerebrospinal fluid (CSF) barriers, alone and in combination with additional nucleoside analogs, was investigated. The bilateral in situ guinea pig brain perfusion method, linked to high-performance liquid chromatography analyses, was used to examine 3TC uptake into brain and CSF simultaneously. The influence of transport inhibitors and additional nucleoside analogs on this uptake was investigated. 3TC movement across the blood-CSF barrier was examined in more detail by the isolated choroid plexus model. 3TC movement across the brain barriers and subsequent accumulation in the brain and CSF was low. However, 3TC uptake from blood into choroid plexus (a potential CNS target for HIV treatment) was significant, and was facilitated by a digoxin-sensitive transporter. Another transporter was identified, which removed 3TC from the choroid plexus. Abacavir, 2'3'-didehydro-3'deoxythymidine, and 3'-azido 3'-deoxythymidine did not interact with 3TC at either of the brain barriers to affect CNS concentrations of 3TC. However, a significant interaction between 3TC and 2'3'-dideoxyinosine was observed at the choroid plexus, and it may prove beneficial to select drug combinations where no such interaction is indicated.
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Affiliation(s)
- J E Gibbs
- Centre for Neuroscience, Guy's King's and St Thomas' School of Biomedical Science, King's College London, Guy's Hospital Campus, London Bridge, London, United Kingdom
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Strazielle N, Belin MF, Ghersi-Egea JF. Choroid plexus controls brain availability of anti-HIV nucleoside analogs via pharmacologically inhibitable organic anion transporters. AIDS 2003; 17:1473-85. [PMID: 12824785 DOI: 10.1097/00002030-200307040-00008] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
OBJECTIVE In AIDS, early suppression of the viral load in the central nervous system is critical for the efficacy of antiretroviral therapy, in order to prevent the emergence of a reservoir of resistant strains of virus, and brain impairment in late stages of the infection. The blood-cerebrospinal fluid (CSF) interface (i.e. the choroidal epithelium) constitutes the most direct route to reach the ventricular meningeal and perivascular infected macrophages, and may modulate the cerebral biodisposition of antiretroviral drugs through various transport systems. Our aim was to address nucleoside drug transfer specifically across the blood-CSF interface, and identify the possible mechanisms involved in their transport. METHODS Drug influx and efflux were measured using an in vitro cellular model that reproduces the barrier and transport properties of the blood-CSF interface in vivo. Transport mechanisms were investigated by competition studies. RESULTS The CSF influx rate of zidovudine was the highest, although moderate, followed by that of stavudine. The permeability coefficients of the other drugs tested were low. Zidovudine influx into the CSF is independent of thymidine transport systems, and more importantly is limited by an efflux mechanism. This efflux involves an apical (CSF-facing) carrier belonging to the solute carrier (Slc) 22 family of organic anion transporters, and can be inhibited by a therapeutic concentration of benzbromarone. CONCLUSIONS The demonstration and characterization of this efflux mechanism is the basis for the development of specific inhibitory agents in view to increase the delivery of antiretroviral nucleoside analogs to the brain.
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Affiliation(s)
- Nathalie Strazielle
- Research and Development in Neuropharmacology, INSERM U433, Faculté de Médecine Laennec, Rue Guillaume Paradin, 69372 Lyon cedex 08, France.
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Begley DJ, Brightman MW. Structural and functional aspects of the blood-brain barrier. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 2003; 61:39-78. [PMID: 14674608 DOI: 10.1007/978-3-0348-8049-7_2] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- David J Begley
- Centre for Neuroscience Research, Kings College London, Hodgkin Building, Guy's Campus, London SE1 1UL, UK.
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