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Varghese SM, Patel S, Nandan A, Jose A, Ghosh S, Sah RK, Menon B, K V A, Chakravarty S. Unraveling the Role of the Blood-Brain Barrier in the Pathophysiology of Depression: Recent Advances and Future Perspectives. Mol Neurobiol 2024:10.1007/s12035-024-04205-5. [PMID: 38730081 DOI: 10.1007/s12035-024-04205-5] [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: 08/03/2023] [Accepted: 04/19/2024] [Indexed: 05/12/2024]
Abstract
Depression is a highly prevalent psychological disorder characterized by persistent dysphoria, psychomotor retardation, insomnia, anhedonia, suicidal ideation, and a remarkable decrease in overall well-being. Despite the prevalence of accessible antidepressant therapies, many individuals do not achieve substantial improvement. Understanding the multifactorial pathophysiology and the heterogeneous nature of the disorder could lead the way toward better outcomes. Recent findings have elucidated the substantial impact of compromised blood-brain barrier (BBB) integrity on the manifestation of depression. BBB functions as an indispensable defense mechanism, tightly overseeing the transport of molecules from the periphery to preserve the integrity of the brain parenchyma. The dysfunction of the BBB has been implicated in a multitude of neurological disorders, and its disruption and consequent brain alterations could potentially serve as important factors in the pathogenesis and progression of depression. In this review, we extensively examine the pathophysiological relevance of the BBB and delve into the specific modifications of its components that underlie the complexities of depression. A particular focus has been placed on examining the effects of peripheral inflammation on the BBB in depression and elucidating the intricate interactions between the gut, BBB, and brain. Furthermore, this review encompasses significant updates on the assessment of BBB integrity and permeability, providing a comprehensive overview of the topic. Finally, we outline the therapeutic relevance and strategies based on BBB in depression, including COVID-19-associated BBB disruption and neuropsychiatric implications. Understanding the comprehensive pathogenic cascade of depression is crucial for shaping the trajectory of future research endeavors.
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Affiliation(s)
- Shamili Mariya Varghese
- Department of Pharmacology, Amrita School of Pharmacy, Amrita Vishwa Vidyapeetham, AIMS Health Sciences Campus, Kochi, Kerala, 682 041, India
| | - Shashikant Patel
- Applied Biology Division, CSIR-Indian Institute of Chemical Technology, Tarnaka, Uppal Road, Hyderabad, Telangana, 500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Amritasree Nandan
- Department of Pharmacology, Amrita School of Pharmacy, Amrita Vishwa Vidyapeetham, AIMS Health Sciences Campus, Kochi, Kerala, 682 041, India
| | - Anju Jose
- Department of Pharmacology, Amrita School of Pharmacy, Amrita Vishwa Vidyapeetham, AIMS Health Sciences Campus, Kochi, Kerala, 682 041, India
| | - Soumya Ghosh
- Applied Biology Division, CSIR-Indian Institute of Chemical Technology, Tarnaka, Uppal Road, Hyderabad, Telangana, 500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Ranjay Kumar Sah
- Department of Pharmacology, Amrita School of Pharmacy, Amrita Vishwa Vidyapeetham, AIMS Health Sciences Campus, Kochi, Kerala, 682 041, India
| | - Bindu Menon
- Department of Psychiatry, Amrita School of Medicine, Amrita Vishwa Vidyapeetham, AIMS Health Sciences Campus, Kochi, Kerala, 682 041, India
| | - Athira K V
- Department of Pharmacology, Amrita School of Pharmacy, Amrita Vishwa Vidyapeetham, AIMS Health Sciences Campus, Kochi, Kerala, 682 041, India.
| | - Sumana Chakravarty
- Applied Biology Division, CSIR-Indian Institute of Chemical Technology, Tarnaka, Uppal Road, Hyderabad, Telangana, 500007, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India.
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Mairinger S, Leterrier S, Filip T, Löbsch M, Pahnke J, Hernández-Lozano I, Stanek J, Tournier N, Zeitlinger M, Hacker M, Langer O, Wanek T. [ 11C]metoclopramide is a sensitive radiotracer to measure moderate decreases in P-glycoprotein function at the blood-brain barrier. J Cereb Blood Flow Metab 2024; 44:142-152. [PMID: 37728771 PMCID: PMC10905639 DOI: 10.1177/0271678x231202336] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 08/23/2023] [Accepted: 08/27/2023] [Indexed: 09/21/2023]
Abstract
The efflux transporter P-glycoprotein (P-gp) at the blood-brain barrier limits the cerebral uptake of various xenobiotics. To assess the sensitivity of [11C]metoclopramide to measure decreased cerebral P-gp function, we performed [11C]metoclopramide PET scans without (baseline) and with partial P-gp inhibition by tariquidar in wild-type, heterozygous Abcb1a/b(+/-) and homozygous Abcb1a/b(-/-) mice as models with controlled levels of cerebral P-gp expression. Brains were collected to quantify P-gp expression with immunohistochemistry. Brain uptake of [11C]metoclopramide was expressed as the area under the brain time-activity curve (AUCbrain) and compared with data previously obtained with (R)-[11C]verapamil and [11C]N-desmethyl-loperamide. Abcb1a/b(+/-) mice had intermediate P-gp expression compared to wild-type and Abcb1a/b(-/-) mice. In baseline scans, all three radiotracers were able to discriminate Abcb1a/b(-/-) from wild-type mice (2.5- to 4.6-fold increased AUCbrain, p ≤ 0.0001). However, only [11C]metoclopramide could discriminate Abcb1a/b(+/-) from wild-type mice (1.46-fold increased AUCbrain, p ≤ 0.001). After partial P-gp inhibition, differences in [11C]metoclopramide AUCbrain between Abcb1a/b(+/-) and wild-type mice (1.39-fold, p ≤ 0.001) remained comparable to baseline. There was a negative correlation between baseline [11C]metoclopramide AUCbrain and ex-vivo-measured P-gp immunofluorescence (r = -0.9875, p ≤ 0.0001). Our data suggest that [11C]metoclopramide is a sensitive radiotracer to measure moderate, but (patho-)physiologically relevant decreases in cerebral P-gp function without the need to co-administer a P-gp inhibitor.
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Affiliation(s)
- Severin Mairinger
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
- Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Sarah Leterrier
- Laboratoire d'Imagerie Biomédicale Multimodale (BIOMAPS), Université Paris-Saclay, CEA, CNRS, Inserm, Service Hospitalier Frédéric Joliot, Orsay, France
| | - Thomas Filip
- Core Facility Laboratory Animal Breeding and Husbandry, Medical University of Vienna, Vienna, Austria
- Institute of Animal Breeding and Genetics & Biomodels Austria, University of Veterinary Medicine, Vienna, Austria
| | - Mathilde Löbsch
- Core Facility Laboratory Animal Breeding and Husbandry, Medical University of Vienna, Vienna, Austria
| | - Jens Pahnke
- Department of Pathology, Section of Neuropathology Research, University of Oslo (UiO) and Oslo University Hospital (OUS), Oslo, Norway
- Drug Development and Chemical Biology Lab, Lübeck Institute of Dermatology (LIED), University of Lübeck, Lübeck, Germany
- Department of Pharmacology, Faculty of Medicine, University of Latvia, Rīga, Latvia
- Department of Neurobiology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | | | - Johann Stanek
- Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Nicolas Tournier
- Laboratoire d'Imagerie Biomédicale Multimodale (BIOMAPS), Université Paris-Saclay, CEA, CNRS, Inserm, Service Hospitalier Frédéric Joliot, Orsay, France
| | - Markus Zeitlinger
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Marcus Hacker
- Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Oliver Langer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
- Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Thomas Wanek
- Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
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PET imaging of animal models with depressive-like phenotypes. Eur J Nucl Med Mol Imaging 2023; 50:1564-1584. [PMID: 36642759 PMCID: PMC10119194 DOI: 10.1007/s00259-022-06073-4] [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: 07/08/2022] [Accepted: 12/03/2022] [Indexed: 01/17/2023]
Abstract
Major depressive disorder is a growing and poorly understood pathology. Due to technical and ethical limitations, a significant proportion of the research on depressive disorders cannot be performed on patients, but needs to be investigated in animal paradigms. Over the years, animal studies have provided new insight in the mechanisms underlying depression. Several of these studies have used PET imaging for the non-invasive and longitudinal investigation of the brain physiology. This review summarises the findings of preclinical PET imaging in different experimental paradigms of depression and compares these findings with observations from human studies. Preclinical PET studies in animal models of depression can be divided into three main different approaches: (a) investigation of glucose metabolism as a biomarker for regional and network involvement, (b) evaluation of the availability of different neuroreceptor populations associated with depressive phenotypes, and (c) monitoring of the inflammatory response in phenotypes of depression. This review also assesses the relevance of the use of PET imaging techniques in animal paradigms for the understanding of specific aspects of the depressive-like phenotypes, in particular whether it might contribute to achieve a more detailed characterisation of the clinical depressive phenotypes for the development of new therapies for depression.
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Medina-Rodriguez EM, Beurel E. Blood brain barrier and inflammation in depression. Neurobiol Dis 2022; 175:105926. [PMID: 36375722 PMCID: PMC10035601 DOI: 10.1016/j.nbd.2022.105926] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 10/26/2022] [Accepted: 11/09/2022] [Indexed: 11/13/2022] Open
Abstract
The blood brain barrier (BBB) is a vital structure to protect the brain, tightly filtering the passage of nutrients and molecules from the blood to the brain. This is critical for maintaining the proper functioning of the brain, and any disruption in the BBB has detrimental consequences often leading to diseases. It is not clear whether disruption of the BBB occurs first in depression or is the consequence of the disease, however disruption of the BBB has been observed in depressed patients and evidence points to the role of important culprits in depression, stress and inflammation in disrupting the integrity of the BBB. The mechanisms whereby stress, and inflammation affect the BBB remain to be fully understood. Yet, the role of cytokines in regulating tight junction protein expression seems crucial. Altogether, the findings in depression suggest that acting at the BBB level might provide therapeutic benefit in depression.
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Affiliation(s)
- Eva M Medina-Rodriguez
- Department of Psychiatry and Behavioral Sciences, University of Miami, Miami, FL 33136, United States of America
| | - Eléonore Beurel
- Department of Psychiatry and Behavioral Sciences, University of Miami, Miami, FL 33136, United States of America; Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, United States of America.
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Dalla C, Pavlidi P, Sakelliadou DG, Grammatikopoulou T, Kokras N. Sex Differences in Blood–Brain Barrier Transport of Psychotropic Drugs. Front Behav Neurosci 2022; 16:844916. [PMID: 35677576 PMCID: PMC9169874 DOI: 10.3389/fnbeh.2022.844916] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 04/27/2022] [Indexed: 11/13/2022] Open
Abstract
Treatment of neuropsychiatric disorders relies on the effective delivery of therapeutic molecules to the target organ, the brain. The blood–brain barrier (BBB) hinders such delivery and proteins acting as transporters actively regulate the influx and importantly the efflux of both endo- and xeno-biotics (including medicines). Neuropsychiatric disorders are also characterized by important sex differences, and accumulating evidence supports sex differences in the pharmacokinetics and pharmacodynamics of many drugs that act on the brain. In this minireview we gather preclinical and clinical findings on how sex and sex hormones can influence the activity of those BBB transporter systems and affect the brain pharmacokinetics of psychotropic medicines. It emerges that it is not well understood which psychotropics are substrates for each of the many and not well-studied brain transporters. Indeed, most evidence originates from studies performed in peripheral tissues, such as the liver and the kidneys. None withstanding, accumulated evidence supports the existence of several sex differences in expression and activity of transport proteins, and a further modulating role of gonadal hormones. It is proposed that a closer study of sex differences in the active influx and efflux of psychotropics from the brain may provide a better understanding of sex-dependent brain pharmacokinetics and pharmacodynamics of psychotropic medicines.
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Affiliation(s)
- Christina Dalla
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Pavlina Pavlidi
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Danai-Georgia Sakelliadou
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Tatiana Grammatikopoulou
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Nikolaos Kokras
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
- First Department of Psychiatry, Eginition Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
- *Correspondence: Nikolaos Kokras,
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Dion-Albert L, Bandeira Binder L, Daigle B, Hong-Minh A, Lebel M, Menard C. Sex differences in the blood-brain barrier: Implications for mental health. Front Neuroendocrinol 2022; 65:100989. [PMID: 35271863 DOI: 10.1016/j.yfrne.2022.100989] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 02/07/2022] [Accepted: 02/19/2022] [Indexed: 12/13/2022]
Abstract
Prevalence of mental disorders, including major depressive disorder (MDD), bipolar disorder (BD) and schizophrenia (SZ) are increasing at alarming rates in our societies. Growing evidence points toward major sex differences in these conditions, and high rates of treatment resistance support the need to consider novel biological mechanisms outside of neuronal function to gain mechanistic insights that could lead to innovative therapies. Blood-brain barrier alterations have been reported in MDD, BD and SZ. Here, we provide an overview of sex-specific immune, endocrine, vascular and transcriptional-mediated changes that could affect neurovascular integrity and possibly contribute to the pathogenesis of mental disorders. We also identify pitfalls in current literature and highlight promising vascular biomarkers. Better understanding of how these adaptations can contribute to mental health status is essential not only in the context of MDD, BD and SZ but also cardiovascular diseases and stroke which are associated with higher prevalence of these conditions.
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Affiliation(s)
- Laurence Dion-Albert
- Department of Psychiatry and Neuroscience, Faculty of Medicine and CERVO Brain Research Center, Université Laval, Quebec City, Canada
| | - Luisa Bandeira Binder
- Department of Psychiatry and Neuroscience, Faculty of Medicine and CERVO Brain Research Center, Université Laval, Quebec City, Canada
| | - Beatrice Daigle
- Department of Psychiatry and Neuroscience, Faculty of Medicine and CERVO Brain Research Center, Université Laval, Quebec City, Canada
| | - Amandine Hong-Minh
- Smurfit Institute of Genetics, Trinity College Dublin, Lincoln Place Gate, Dublin 2, Ireland
| | - Manon Lebel
- Department of Psychiatry and Neuroscience, Faculty of Medicine and CERVO Brain Research Center, Université Laval, Quebec City, Canada
| | - Caroline Menard
- Department of Psychiatry and Neuroscience, Faculty of Medicine and CERVO Brain Research Center, Université Laval, Quebec City, Canada.
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Toyohara J, Sakata M, Ishibashi K, Mossel P, Imai M, Wagatsuma K, Tago T, Imabayashi E, Colabufo NA, Luurtsema G, Ishii K. First clinical assessment of [ 18F]MC225, a novel fluorine-18 labelled PET tracer for measuring functional P-glycoprotein at the blood-brain barrier. Ann Nucl Med 2021; 35:1240-1252. [PMID: 34368924 DOI: 10.1007/s12149-021-01666-9] [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: 05/25/2021] [Accepted: 08/02/2021] [Indexed: 12/01/2022]
Abstract
OBJECTIVE 5-(1-(2-[18F]fluoroethoxy))-[3-(6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-propyl]-5,6,7,8-tetrahydronaphthalen ([18F]MC225) is a selective substrate for P-glycoprotein (P-gp), possessing suitable properties for measuring overexpression of P-gp in the brain. This is the first-in-human study to examine safety, radiation dosimetry and P-gp function at the blood-brain barrier (BBB) of [18F]MC225 in healthy subjects. METHODS [18F]MC225 biodistribution and dosimetry were determined in 3 healthy male subjects, using serial 2 h and intermittent 4 and 6 h whole-body PET scans acquired after [18F]MC225 injection. Dynamic [18F]MC225 brain PET (90 min) was obtained in 5 healthy male subjects. Arterial blood was sampled at various time intervals during scanning and the fraction of unchanged [18F]MC225 in plasma was determined. T1-weighted MRI was performed for anatomical coregistration. Total distribution volume (VT) was estimated using 1- and 2-tissue-compartment models (1-TCM and 2-TCM, respectively). VT was also estimated using the Logan graphical method (Logan plot) (t* = 20 min). Surrogate parameters without blood sampling (area-under the curve [AUC] of regional time-activity curves [TACs] and negative slope of calculated TACs) were compared with the VT values. RESULTS No serious adverse events occurred throughout the study period. Although biodistribution implied hepatobiliary excretion, secretion of radioactivity from liver to small intestine through the gallbladder was very slow. Total renal excreted radioactivity recovered during 6 h after injection was < 2%ID. Absorbed dose was the highest in the pancreas (mean ± SD, 203 ± 45 μGy/MBq) followed by the liver (83 ± 11 μGy/MBq). Mean effective dose with and without urination was 17 ± 1 μSv/MBq. [18F]MC225 readily entered the brain, distributing homogeneously in grey matter regions. 2-TCM provided lower Akaike information criterion scores than did 1-TCM. VT estimated by Logan plot was well correlated with that of 2-TCM (r2 > 0.9). AUCs of TACs were positively correlated with VT (2-TCM) values (r2: AUC0-60 min = 0.61, AUC0-30 min = 0.62, AUC30-60 min = 0.59, p < 0.0001). Negative slope of SUV TACs was negatively correlated with VT (2-TCM) values (r2 = 0.53, p < 0.0001). CONCLUSIONS This initial evaluation indicated that [18F]MC225 is a suitable and safe PET tracer for measuring P-gp function at the BBB.
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Affiliation(s)
- Jun Toyohara
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan.
| | - Muneyuki Sakata
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Kenji Ishibashi
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Pascalle Mossel
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
| | - Masamichi Imai
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Kei Wagatsuma
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
- School of Allied Health Science, Kitasato University, 1-15-1 Kitasato, Sagamihara, Kanagawa, 252-0373, Japan
| | - Tetsuro Tago
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Etsuko Imabayashi
- Department of Diagnostic Radiology, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Nicola A Colabufo
- Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari, via Orabona 4, 70125, Bari, Italy
| | - Gert Luurtsema
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
| | - Kenji Ishii
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
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Luurtsema G, Pichler V, Bongarzone S, Seimbille Y, Elsinga P, Gee A, Vercouillie J. EANM guideline for harmonisation on molar activity or specific activity of radiopharmaceuticals: impact on safety and imaging quality. EJNMMI Radiopharm Chem 2021; 6:34. [PMID: 34628570 PMCID: PMC8502193 DOI: 10.1186/s41181-021-00149-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 09/20/2021] [Indexed: 02/04/2023] Open
Abstract
This guideline on molar activity (Am) and specific activity (As) focusses on small molecules, peptides and macromolecules radiolabelled for diagnostic and therapeutic applications. In this guideline we describe the definition of Am and As, and how these measurements must be standardised and harmonised. Selected examples highlighting the importance of Am and As in imaging studies of saturable binding sites will be given, and the necessity of using appropriate materials and equipment will be discussed. Furthermore, common Am pitfalls and remedies are described. Finally, some aspects of Am in relation the emergence of a new generation of highly sensitive PET scanners will be discussed.
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Affiliation(s)
- Gert Luurtsema
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands.
| | - Verena Pichler
- Department of Pharmaceutical Sciences, Medical University of Vienna, Vienna, Austria
| | | | - Yann Seimbille
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, The Netherlands
| | - Philip Elsinga
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands
| | - Antony Gee
- Department of Imaging Sciences, King's College London, London, UK
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Head-to-head comparison of (R)-[ 11C]verapamil and [ 18F]MC225 in non-human primates, tracers for measuring P-glycoprotein function. Eur J Nucl Med Mol Imaging 2021; 48:4307-4317. [PMID: 34117508 PMCID: PMC8566421 DOI: 10.1007/s00259-021-05411-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 05/11/2021] [Indexed: 11/03/2022]
Abstract
Purpose P-glycoprotein (P-gp) function is altered in several brain disorders; thus, it is of interest to monitor the P-gp function in vivo using PET. (R)-[11C]verapamil is considered the gold standard tracer to measure the P-gp function; however, it presents some drawbacks that limit its use. New P-gp tracers have been developed with improved properties, such as [18F]MC225. This study compares the characteristics of (R)-[11C]verapamil and [18F]MC225 in the same subjects. Methods Three non-human primates underwent 4 PET scans: 2 with (R)-[11C]verapamil and 2 with [18F]MC225, at baseline and after P-gp inhibition. The 30-min PET data were analyzed using 1-Tissue Compartment Model (1-TCM) and metabolite-corrected plasma as input function. Tracer kinetic parameters at baseline and after inhibition were compared. Regional differences and simplified methods to quantify the P-gp function were also assessed. Results At baseline, [18F]MC225 VT values were higher, and k2 values were lower than those of (R)-[11C]verapamil, whereas K1 values were not significantly different. After inhibition, VT values of the 2 tracers were similar; however, (R)-[11C]verapamil K1 and k2 values were higher than those of [18F]MC225. Significant regional differences between tracers were found at baseline, which disappeared after inhibition. The positive slope of the SUV-TAC was positively correlated to the K1 and VT of both tracers. Conclusion [18F]MC225 and (R)-[11C]verapamil show comparable sensitivity to measure the P-gp function in non-human primates. Moreover, this study highlights the 30-min VT as the best parameter to measure decreases in the P-gp function with both tracers. [18F]MC225 may become the first radiofluorinated tracer able to measure decreases and increases in the P-gp function due to its higher baseline VT. Supplementary Information The online version contains supplementary material available at 10.1007/s00259-021-05411-2.
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García-Varela L, García DV, Kakiuchi T, Ohba H, Nishiyama S, Tago T, Elsinga PH, Tsukada H, Colabufo NA, Dierckx RAJO, van Waarde A, Toyohara J, Boellaard R, Luurtsema G. Pharmacokinetic Modeling of ( R)-[ 11C]verapamil to Measure the P-Glycoprotein Function in Nonhuman Primates. Mol Pharm 2020; 18:416-428. [PMID: 33315404 PMCID: PMC7788571 DOI: 10.1021/acs.molpharmaceut.0c01014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
(R)-[11C]verapamil is a radiotracer
widely used for the evaluation of the P-glycoprotein (P-gp) function
at the blood–brain barrier (BBB). Several studies have evaluated
the pharmacokinetics of (R)-[11C]verapamil
in rats and humans under different conditions. However, to the best
of our knowledge, the pharmacokinetics of (R)-[11C]verapamil have not yet been evaluated in nonhuman primates.
Our study aims to establish (R)-[11C]verapamil
as a reference P-gp tracer for comparison of a newly developed P-gp
positron emission tomography (PET) tracer in a species close to humans.
Therefore, the study assesses the kinetics of (R)-[11C]verapamil and evaluates the effect of scan duration and
P-gp inhibition on estimated pharmacokinetic parameters. Three nonhuman
primates underwent two dynamic 91 min PET scans with arterial blood
sampling, one at baseline and another after inhibition of the P-gp
function. The (R)-[11C]verapamil data
were analyzed using 1-tissue compartment model (1-TCM) and 2-tissue
compartment model fits using plasma-corrected for polar radio-metabolites
or non-corrected for radio-metabolites as an input function and with
various scan durations (10, 20, 30, 60, and 91 min). The preferred
model was chosen according to the Akaike information criterion and
the standard errors (SE %) of the estimated parameters. 1-TCM was
selected as the model of choice to analyze the (R)-[11C]verapamil data at baseline and after inhibition
and for all scan durations tested. The volume of distribution (VT) and the efflux constant k2 estimations were affected by the evaluated scan durations,
whereas the influx constant K1 estimations
remained relatively constant. After P-gp inhibition (tariquidar, 8
mg/kg), in a 91 min scan duration, the whole-brain VT increased significantly up to 208% (p < 0.001) and K1 up to 159% (p < 0.001) compared with baseline scans. The k2 values decreased significantly after P-gp
inhibition in all the scan durations except for the 91 min scans.
This study suggests the use of K1, calculated
with 1-TCM and using short PET scans (10 to 30 min), as a suitable
parameter to measure the P-gp function at the BBB of nonhuman primates.
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Affiliation(s)
- Lara García-Varela
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, Groningen 9713 GZ, The Netherlands
| | - David Vállez García
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, Groningen 9713 GZ, The Netherlands
| | - Takeharu Kakiuchi
- Central Research Laboratory, Hamamatsu Photonics KK, 5000 Hirakuchi, Hamakita, Hamamatsu 434-8601, Shizuoka, Japan
| | - Hiroyuki Ohba
- Central Research Laboratory, Hamamatsu Photonics KK, 5000 Hirakuchi, Hamakita, Hamamatsu 434-8601, Shizuoka, Japan
| | - Shingo Nishiyama
- Central Research Laboratory, Hamamatsu Photonics KK, 5000 Hirakuchi, Hamakita, Hamamatsu 434-8601, Shizuoka, Japan
| | - Tetsuro Tago
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan
| | - Philip H Elsinga
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, Groningen 9713 GZ, The Netherlands
| | - Hideo Tsukada
- Central Research Laboratory, Hamamatsu Photonics KK, 5000 Hirakuchi, Hamakita, Hamamatsu 434-8601, Shizuoka, Japan
| | - Nicola A Colabufo
- Department of Pharmacy, University of Bari Aldo Moro, Bari 70125, Italy.,Biofordrug, Spin-off Università degli Studi di Bari "A. Moro", via Dante 99, Triggiano, Bari 70019, Italy
| | - Rudi A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, Groningen 9713 GZ, The Netherlands
| | - Aren van Waarde
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, Groningen 9713 GZ, The Netherlands
| | - Jun Toyohara
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan
| | - Ronald Boellaard
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, Groningen 9713 GZ, The Netherlands
| | - Gert Luurtsema
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, Groningen 9713 GZ, The Netherlands
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Imagerie TEP pour l’étude des répercussions fonctionnelles de la P-glycoprotéine en neuropharmacocinétique. Therapie 2020; 75:623-632. [DOI: 10.1016/j.therap.2020.02.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 12/03/2019] [Accepted: 02/17/2020] [Indexed: 11/20/2022]
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Toyohara J, Sakata M, Tago T, Colabufo NA, Luurtsema G. Automated synthesis, preclinical toxicity, and radiation dosimetry of [ 18F]MC225 for clinical use: a tracer for measuring P-glycoprotein function at the blood-brain barrier. EJNMMI Res 2020; 10:84. [PMID: 32700099 PMCID: PMC7376787 DOI: 10.1186/s13550-020-00674-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 07/14/2020] [Indexed: 12/27/2022] Open
Abstract
INTRODUCTION [18F]MC225 is a selective substrate for P-glycoprotein (P-gp) that has good metabolic stability and shows higher baseline uptake compared with other P-gp substrates such as (R)-[11C]Verapamil. Prior to clinical translation, it is necessary to perform process validation of the radiosynthesis, assessment of preclinical toxicity, and radiation dosimetry. METHODS The production of [18F]MC225 was automated on a CFN-MPS200 multipurpose synthesizer. The acute toxicity of MC225 was evaluated at a dose of 2.5 mg/kg bodyweight, which is more than 10,000-fold the postulated maximum clinical dose of [18F]MC225. The acute toxicity of [18F]MC225 injection at a 200-fold dose, to administer a postulated dose of 185 MBq of [18F]MC225, was also evaluated after the decay-out of 18F. The mutagenicity of MC225 was studied by a reverse mutation test using Salmonella typhimurium and Escherichia coli (Ames test). In vivo biodistribution and dosimetry studies of [18F]MC225 were carried out in normal mice. Human dosimetry was estimated using OLINDA software. RESULTS The mean decay-corrected yields of [18F]MC225 at end of synthesis were 13%, with > 99% radiochemical purity, > 1000 GBq/μmol molar activity, and ≤ 1.5 μg/185 MBq of total chemical contents. All process validation batches complied with the product specifications and the process was confirmed to be appropriate for the production of [18F]MC225. No acute toxicity of MC225 or [18F]MC225 injection was found. No mutagenic activity was observed for MC225. The biodistribution study demonstrated both hepatobiliary and renal excretion of radioactivity. The most critical organ was the pancreas, with (63.8 μGy/MBq) or without urination (63.9 μGy/MBq) at 360 min after injection. The estimated effective dose (μSv/MBq) with and without urination at 360 min after injection was calculated as 15.7 and 16.9, respectively. CONCLUSION [18F]MC225 shows acceptable pharmacological safety at the dose required for adequate PET imaging. The potential risk associated with [18F]MC225 PET imaging is well within acceptable dose limits.
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Affiliation(s)
- Jun Toyohara
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Muneyuki Sakata
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Tetsuro Tago
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Nicola A. Colabufo
- Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari Aldo Moro, Bari, Italy
| | - Gert Luurtsema
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen and University Medical Centre Groningen, Groningen, The Netherlands
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Gil-Martins E, Barbosa DJ, Silva V, Remião F, Silva R. Dysfunction of ABC transporters at the blood-brain barrier: Role in neurological disorders. Pharmacol Ther 2020; 213:107554. [PMID: 32320731 DOI: 10.1016/j.pharmthera.2020.107554] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 04/07/2020] [Indexed: 12/14/2022]
Abstract
ABC (ATP-binding cassette) transporters represent one of the largest and most diverse superfamily of proteins in living species, playing an important role in many biological processes such as cell homeostasis, cell signaling, drug metabolism and nutrient uptake. Moreover, using the energy generated from ATP hydrolysis, they mediate the efflux of endogenous and exogenous substrates from inside the cells, thereby reducing their intracellular accumulation. At present, 48 ABC transporters have been identified in humans, which were classified into 7 different subfamilies (A to G) according to their phylogenetic analysis. Nevertheless, the most studied members with importance in drug therapeutic efficacy and toxicity include P-glycoprotein (P-gp), a member of the ABCB subfamily, the multidrug-associated proteins (MPRs), members of the ABCC subfamily, and breast cancer resistance protein (BCRP), a member of the ABCG subfamily. They exhibit ubiquitous expression throughout the human body, with a special relevance in barrier tissues like the blood-brain barrier (BBB). At this level, they play a physiological function in tissue protection by reducing or limiting the brain accumulation of neurotoxins. Furthermore, dysfunction of ABC transporters, at expression and/or activity level, has been associated with many neurological diseases, including epilepsy, multiple sclerosis, Alzheimer's disease, and amyotrophic lateral sclerosis. Additionally, these transporters are strikingly associated with the pharmacoresistance to central nervous system (CNS) acting drugs, because they contribute to the decrease in drug bioavailability. This article reviews the signaling pathways that regulate the expression and activity of P-gp, BCRP and MRPs subfamilies of transporters, with particular attention at the BBB level, and their mis-regulation in neurological disorders.
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Affiliation(s)
- Eva Gil-Martins
- UCIBIO-REQUIMTE, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Daniel José Barbosa
- Instituto de Biologia Molecular e Celular (IBMC), Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal.
| | - Vera Silva
- UCIBIO-REQUIMTE, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Fernando Remião
- UCIBIO-REQUIMTE, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
| | - Renata Silva
- UCIBIO-REQUIMTE, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
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Marie N, Canestrelli C, Noble F. Role of pharmacokinetic and pharmacodynamic parameters in neuroadaptations induced by drugs of abuse, with a focus on opioids and psychostimulants. Neurosci Biobehav Rev 2019; 106:217-226. [DOI: 10.1016/j.neubiorev.2018.06.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 05/29/2018] [Accepted: 06/06/2018] [Indexed: 01/16/2023]
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Morris G, Fernandes BS, Puri BK, Walker AJ, Carvalho AF, Berk M. Leaky brain in neurological and psychiatric disorders: Drivers and consequences. Aust N Z J Psychiatry 2018; 52:924-948. [PMID: 30231628 DOI: 10.1177/0004867418796955] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND The blood-brain barrier acts as a highly regulated interface; its dysfunction may exacerbate, and perhaps initiate, neurological and neuropsychiatric disorders. METHODS In this narrative review, focussing on redox, inflammatory and mitochondrial pathways and their effects on the blood-brain barrier, a model is proposed detailing mechanisms which might explain how increases in blood-brain barrier permeability occur and can be maintained with increasing inflammatory and oxidative and nitrosative stress being the initial drivers. RESULTS Peripheral inflammation, which is causatively implicated in the pathogenesis of major psychiatric disorders, is associated with elevated peripheral pro-inflammatory cytokines, which in turn cause increased blood-brain barrier permeability. Reactive oxygen species, such as superoxide radicals and hydrogen peroxide, and reactive nitrogen species, such as nitric oxide and peroxynitrite, play essential roles in normal brain capillary endothelial cell functioning; however, chronically elevated oxidative and nitrosative stress can lead to mitochondrial dysfunction and damage to the blood-brain barrier. Activated microglia, redox control of which is mediated by nitric oxide synthases and nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, secrete neurotoxic molecules such as reactive oxygen species, nitric oxide, prostaglandin, cyclooxygenase-2, quinolinic acid, several chemokines (including monocyte chemoattractant protein-1 [MCP-1], C-X-C motif chemokine ligand 1 [CXCL-1] and macrophage inflammatory protein 1α [MIP-1α]) and the pro-inflammatory cytokines interleukin-6, tumour necrosis factor-α and interleukin-1β, which can exert a detrimental effect on blood-brain barrier integrity and function. Similarly, reactive astrocytes produce neurotoxic molecules such as prostaglandin E2 and pro-inflammatory cytokines, which can cause a 'leaky brain'. CONCLUSION Chronic inflammatory and oxidative and nitrosative stress is associated with the development of a 'leaky gut'. The following evidence-based approaches, which address the leaky gut and blood-brain barrier dysfunction, are suggested as potential therapeutic interventions for neurological and neuropsychiatric disorders: melatonin, statins, probiotics containing Bifidobacteria and Lactobacilli, N-acetylcysteine, and prebiotics containing fructo-oligosaccharides and galacto-oligosaccharides.
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Affiliation(s)
- Gerwyn Morris
- 1 IMPACT Strategic Research Centre, Deakin University School of Medicine, and Barwon Health, Geelong, VIC, Australia
| | - Brisa S Fernandes
- 1 IMPACT Strategic Research Centre, Deakin University School of Medicine, and Barwon Health, Geelong, VIC, Australia.,2 Centre for Addiction and Mental Health (CAMH) and Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Basant K Puri
- 3 Department of Medicine, Hammersmith Hospital, Imperial College London, London, UK
| | - Adam J Walker
- 1 IMPACT Strategic Research Centre, Deakin University School of Medicine, and Barwon Health, Geelong, VIC, Australia
| | - Andre F Carvalho
- 2 Centre for Addiction and Mental Health (CAMH) and Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Michael Berk
- 1 IMPACT Strategic Research Centre, Deakin University School of Medicine, and Barwon Health, Geelong, VIC, Australia.,4 Orygen, The National Centre of Excellence in Youth Mental Health, The Department of Psychiatry and The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
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Blood-brain barrier regulation in psychiatric disorders. Neurosci Lett 2018; 726:133664. [PMID: 29966749 DOI: 10.1016/j.neulet.2018.06.033] [Citation(s) in RCA: 148] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 06/18/2018] [Indexed: 02/07/2023]
Abstract
The blood-brain barrier (BBB) is a dynamic interface between the peripheral blood supply and the cerebral parenchyma, controlling the transport of material to and from the brain. Tight junctions between the endothelial cells of the cerebral microvasculature limit the passage of large, negatively charged molecules via paracellular diffusion whereas transcellular transportation across the endothelial cell is controlled by a number of mechanisms including transporter proteins, endocytosis, and diffusion. Here, we review the evidence that perturbation of these processes may underlie the development of psychiatric disorders including schizophrenia, autism spectrum disorder (ASD), and affective disorders. Increased permeability of the BBB appears to be a common factor in these disorders, leading to increased infiltration of peripheral material into the brain culminating in neuroinflammation and oxidative stress. However, although there is no common mechanism underpinning BBB dysfunction even within each particular disorder, the tight junction protein claudin-5 may be a clinically relevant target given that both clinical and pre-clinical research has linked it to schizophrenia, ASD, and depression. Additionally, we discuss the clinical significance of the BBB in diagnosis (genetic markers, dynamic contrast-enhanced-magnetic resonance imaging, and blood biomarkers) and in treatment (drug delivery).
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Abstract
Transporter systems involved in the permeation of drugs and solutes across biological membranes are recognized as key determinants of pharmacokinetics. Typically, the action of membrane transporters on drug exposure to tissues in living organisms is inferred from invasive procedures, which cannot be applied in humans. In recent years, imaging methods have greatly progressed in terms of instruments, synthesis of novel imaging probes as well as tools for data analysis. Imaging allows pharmacokinetic parameters in different tissues and organs to be obtained in a non-invasive or minimally invasive way. The aim of this overview is to summarize the current status in the field of molecular imaging of drug transporters. The overview is focused on human studies, both for the characterization of transport systems for imaging agents as well as for the determination of drug pharmacokinetics, and makes reference to animal studies where necessary. We conclude that despite certain methodological limitations, imaging has a great potential to study transporters at work in humans and that imaging will become an important tool, not only in drug development but also in medicine. Imaging allows the mechanistic aspects of transport proteins to be studied, as well as elucidating the influence of genetic background, pathophysiological states and drug-drug interactions on the function of transporters involved in the disposition of drugs.
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Affiliation(s)
- Nicolas Tournier
- Imagerie Moléculaire In Vivo, IMIV, CEA, Inserm, CNRS, Univ. Paris-Sud, Université Paris Saclay, CEA-SHFJ, Orsay, France
| | - Bruno Stieger
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, 8091 Zurich, Switzerland
| | - Oliver Langer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria; Biomedical Systems, Center for Health & Bioresources, AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria; Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.
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18
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Abstract
P-glycoprotein (P-gp), the gene product of ABCB1, is a drug transporter at the blood–brain barrier and could be a limiting factor for entrance of antidepressants into the brain, the target site of antidepressant action. Animal studies showed that brain concentrations of many antidepressants depend on P-gp. In humans, ABCB1 genotyping in the treatment of depression rests on the assumption that genetic variations in ABCB1 explain individual differences in antidepressant response via their effects on P-gp expression at the blood–brain barrier. High P-gp expression is hypothesized to lead to lower and often insufficient brain concentrations of P-gp substrate antidepressants. In this review, we summarize 32 studies investigating the question of whether ABCB1 polymorphisms predict clinical efficacy and/or tolerability of antidepressants in humans and evaluate the clinical application status of ABCB1 genotyping in depression treatment.
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Affiliation(s)
- Tanja Maria Brückl
- Department of Translational Research in Psychiatry, Max Planck Institute of Psychiatry, Kraepelinstr. 2–10, 80804 Munich, Germany
| | - Manfred Uhr
- Clinical Laboratory, Max Planck Institute of Psychiatry, Kraepelinstr. 2–10, 80804 Munich, Germany
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Bundgaard C, Eneberg E, Sánchez C. P-glycoprotein differentially affects escitalopram, levomilnacipran, vilazodone and vortioxetine transport at the mouse blood–brain barrier in vivo. Neuropharmacology 2016; 103:104-11. [DOI: 10.1016/j.neuropharm.2015.12.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 12/09/2015] [Accepted: 12/11/2015] [Indexed: 12/16/2022]
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Toyohara J, Okamoto M, Aramaki H, Zaitsu Y, Shimizu I, Ishiwata K. ( R )-[ 11 C]Emopamil as a novel tracer for imaging enhanced P-glycoprotein function. Nucl Med Biol 2016; 43:52-62. [DOI: 10.1016/j.nucmedbio.2015.09.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Revised: 08/31/2015] [Accepted: 09/03/2015] [Indexed: 11/28/2022]
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Qosa H, Miller DS, Pasinelli P, Trotti D. Regulation of ABC efflux transporters at blood-brain barrier in health and neurological disorders. Brain Res 2015; 1628:298-316. [PMID: 26187753 PMCID: PMC4681613 DOI: 10.1016/j.brainres.2015.07.005] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Revised: 06/28/2015] [Accepted: 07/02/2015] [Indexed: 01/16/2023]
Abstract
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.
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Affiliation(s)
- Hisham Qosa
- Weinberg Unit for ALS Research, Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, 900 Walnut street, Philadelphia, PA 19107, USA.
| | - David S Miller
- Laboratory of Signal Transduction, NIH/NIEHS, Research Triangle Park, NC 27709, USA
| | - Piera Pasinelli
- Weinberg Unit for ALS Research, Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, 900 Walnut street, Philadelphia, PA 19107, USA
| | - Davide Trotti
- Weinberg Unit for ALS Research, Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, 900 Walnut street, Philadelphia, PA 19107, USA.
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Sucrose consumption test reveals pharmacoresistant depression-associated behavior in two mouse models of temporal lobe epilepsy. Exp Neurol 2014; 263:263-71. [PMID: 25220610 DOI: 10.1016/j.expneurol.2014.09.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 08/16/2014] [Accepted: 09/04/2014] [Indexed: 01/21/2023]
Abstract
Among the comorbidities observed in epilepsy patients depression is the most frequent one. Likewise, depression by itself is accompanied by an increased risk to develop epilepsy. Both epilepsy and depression are characterized by a high incidence of pharmacoresistance, which might be based on overactivity of multidrug transporters like P-glycoprotein at the blood-brain barrier. Using genetically modified mice in preclinical epilepsy research is pivotal for investigating this bidirectional relationship. In the present study, we used the sucrose consumption test (SCT) in the pilocarpine and the intrahippocampal kainate mouse post-status epilepticus model to reveal anhedonic behavior, i.e. hyposensitivity to pleasure, as a key symptom of depression. Mice were repetitively investigated by SCT during early epilepsy and the chronic phase of the disease, during which response to antidepressant drug treatment was assessed. SCT revealed long-lasting anhedonia in both models. Anhedonia appeared to be pharmacoresistant, as neither chronic treatment with imipramine in the pilocarpine model nor chronic treatment with fluoxetine in the kainate model could annihilate the differences in sucrose consumption between control and epileptic mice. Moreover, knock-out of P-glycoprotein did not improve the treatment effect of fluoxetine. In conclusion, our findings show for the first time that the SCT is suited for detection of depression-like behavior in mouse models of temporal-lobe epilepsy. Both models might serve as tools to further investigate the neurobiology and pharmacology of epilepsy-associated pharmacoresistant depression.
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Faster, better, stronger: towards new antidepressant therapeutic strategies. Eur J Pharmacol 2014; 753:32-50. [PMID: 25092200 DOI: 10.1016/j.ejphar.2014.07.046] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 05/28/2014] [Accepted: 07/24/2014] [Indexed: 12/26/2022]
Abstract
Major depression is a highly prevalent disorder and is predicted to be the second leading cause of disease burden by 2020. Although many antidepressant drugs are currently available, they are far from optimal. Approximately 50% of patients do not respond to initial first line antidepressant treatment, while approximately one third fail to achieve remission following several pharmacological interventions. Furthermore, several weeks or months of treatment are often required before clinical improvement, if any, is reported. Moreover, most of the commonly used antidepressants have been primarily designed to increase synaptic availability of serotonin and/or noradrenaline and although they are of therapeutic benefit to many patients, it is clear that other therapeutic targets are required if we are going to improve the response and remission rates. It is clear that more effective, rapid-acting antidepressants with novel mechanisms of action are required. The purpose of this review is to outline the current strategies that are being taken in both preclinical and clinical settings for identifying superior antidepressant drugs. The realisation that ketamine has rapid antidepressant-like effects in treatment resistant patients has reenergised the field. Further, developing an understanding of the mechanisms underlying the rapid antidepressant effects in treatment-resistant patients by drugs such as ketamine may uncover novel therapeutic targets that can be exploited to meet the Olympian challenge of developing faster, better and stronger antidepressant drugs.
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O'Leary OF, O'Brien FE, O'Connor RM, Cryan JF. Drugs, genes and the blues: Pharmacogenetics of the antidepressant response from mouse to man. Pharmacol Biochem Behav 2014; 123:55-76. [DOI: 10.1016/j.pbb.2013.10.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 10/04/2013] [Accepted: 10/16/2013] [Indexed: 12/11/2022]
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ABCB1 C3435T polymorphism is associated with susceptibility to major depression, but not with a clinical response to citalopram in a Turkish population. Pharmacol Rep 2014; 66:235-8. [PMID: 24911075 DOI: 10.1016/j.pharep.2013.09.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 09/04/2013] [Accepted: 09/12/2013] [Indexed: 01/16/2023]
Abstract
BACKGROUND The ATP-binding cassette sub-family B member 1 (ABCB1) gene, which encodes the p-glycoprotein at the blood-brain barrier, is investigated for patients' susceptibility to major depressive disorder (MDD) and their therapeutic response to antidepressants. However, there is an inconsistency between the studies of different ethnic groups. The current study aimed to determine the potential correlations of the ABCB1 gene C3435T polymorphism with the susceptibility to MDD and the therapeutic response to citalopram in a Turkish population. METHODS Fifty-four patients with MDD who received citalopram and 70 controls from the Turkish population were genotyped for ABCB1 C3435T polymorphism. To assess the therapeutic response to citalopram, all patients were rated baseline, first, second, fourth and sixth weeks according to the 17-item Hamilton Rating Scale for Depression (HAMD-17). RESULTS There was a significant correlation between the patient and control groups for ABCB1 C3435T polymorphism. Distribution of CC genotype and C allele frequency were higher in the patients than in the control group (p = 0.006, p = 0.020, respectively). However, no correlation between ABCB1 C3435T polymorphism and a therapeutic response to citalopram was observed. CONCLUSION Our results suggested that C3435T polymorphism in the ABCB1 gene may be an indicator of the susceptibility to major depression, without a likely treatment response to citalopram in a Turkish population. These findings should be replicated in studies on larger patient groups with different ethnicities.
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Najjar S, Pearlman DM, Devinsky O, Najjar A, Zagzag D. Neurovascular unit dysfunction with blood-brain barrier hyperpermeability contributes to major depressive disorder: a review of clinical and experimental evidence. J Neuroinflammation 2013; 10:142. [PMID: 24289502 PMCID: PMC4220803 DOI: 10.1186/1742-2094-10-142] [Citation(s) in RCA: 154] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 11/15/2013] [Indexed: 12/27/2022] Open
Abstract
About one-third of people with major depressive disorder (MDD) fail at least two antidepressant drug trials at 1 year. Together with clinical and experimental evidence indicating that the pathophysiology of MDD is multifactorial, this observation underscores the importance of elucidating mechanisms beyond monoaminergic dysregulation that can contribute to the genesis and persistence of MDD. Oxidative stress and neuroinflammation are mechanistically linked to the presence of neurovascular dysfunction with blood-brain barrier (BBB) hyperpermeability in selected neurological disorders, such as stroke, epilepsy, multiple sclerosis, traumatic brain injury, and Alzheimer’s disease. In contrast to other major psychiatric disorders, MDD is frequently comorbid with such neurological disorders and constitutes an independent risk factor for morbidity and mortality in disorders characterized by vascular endothelial dysfunction (cardiovascular disease and diabetes mellitus). Oxidative stress and neuroinflammation are implicated in the neurobiology of MDD. More recent evidence links neurovascular dysfunction with BBB hyperpermeability to MDD without neurological comorbidity. We review this emerging literature and present a theoretical integration between these abnormalities to those involving oxidative stress and neuroinflammation in MDD. We discuss our hypothesis that alterations in endothelial nitric oxide levels and endothelial nitric oxide synthase uncoupling are central mechanistic links in this regard. Understanding the contribution of neurovascular dysfunction with BBB hyperpermeability to the pathophysiology of MDD may help to identify novel therapeutic and preventative approaches.
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Affiliation(s)
- Souhel Najjar
- Department of Neurology, Neuroinflammation Research Group, Epilepsy Center Division, NYU School of Medicine, New York, NY 10016, USA.
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Conen S, Theunissen EL, Vermeeren A, van Ruitenbeek P, Stiers P, Mehta MA, Toennes SW, Ramaekers JG. The role of P-glycoprotein in CNS antihistamine effects. Psychopharmacology (Berl) 2013; 229:9-19. [PMID: 23564211 DOI: 10.1007/s00213-013-3075-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 03/18/2013] [Indexed: 01/16/2023]
Abstract
RATIONALE P-glycoprotein (P-gp) is a drug efflux pump expressed, amongst others, on the luminal surface of the cerebral endothelial cells forming the blood-brain barrier. Studies in rodents have demonstrated that antihistamines that are substrates of the P-gp transporter display no or minor central nervous system (CNS) effects as compared to antihistamines that are not P-gp transporter substrates. OBJECTIVES The present study explored whether P-gp contributes in similar ways to the occurrence of sedative effects of antihistamines in humans. METHODS An fMRI study was conducted according to a double-blind, randomized, placebo-controlled, cross-over design in 13 healthy volunteers. Participants received cetirizine 15 mg (an antihistamine), verapamil 120 mg (a P-gp blocker), a combination of cetirizine + verapamil, and a placebo. Brain activity was assessed while conducting the attention network test (ANT) in a 3T magnetic resonance scanner. The ANT measures three independent attention domains: i.e., alerting, orienting, and executive attention. It was expected that the combined treatment of cetirizine with verapamil would prevent efflux of cetirizine from the CNS, thus increasing attentional impairment, as compared to cetirizine administered alone. RESULTS The present study provides evidence that the P-gp transporter is involved in central antihistamine effects in humans. Participants were less alert during the combined treatment of cetirizine and verapamil as indicated by longer reaction times and decreased blood oxygen level-dependent response in the right superior temporal gyrus. CONCLUSION It is concluded that the affinity for the P-gp transporter may contribute to the lower incidence of CNS side effects of certain antihistamines.
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Affiliation(s)
- Silke Conen
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands.
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Smith DF, Jakobsen S. Molecular Neurobiology of Depression: PET Findings on the Elusive Correlation with Symptom Severity. Front Psychiatry 2013; 4:8. [PMID: 23459670 PMCID: PMC3586775 DOI: 10.3389/fpsyt.2013.00008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 02/11/2013] [Indexed: 01/08/2023] Open
Abstract
Molecular mechanisms in the brain are assumed to cause the symptoms and severity of neuropsychiatric disorders. This review concerns the elusive nature of relationships between the severity of depressive disorders and neuromolecular processes studied by positron emission tomography (PET). Recent PET studies of human depression have focused on serotonergic, dopaminergic, muscarinic, nicotinic, and GABAergic receptors, as well as central processes dependent on monoamine oxidase, phosphodiesterase type 4, amyloid plaques, neurofibrillar tangles, and P-glycoprotein. We find that reliable causal links between neuromolecular mechanisms and relief from depressive disorders have yet to be convincingly demonstrated. This situation may contribute to the currently limited use of PET for exploring the neuropathways that are currently viewed as being responsible for beneficial effects of antidepressant treatment regimes.
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Affiliation(s)
- Donald F Smith
- Center for Psychiatric Research, Psychiatric Hospital of Aarhus University Risskov, Denmark
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In Vivo Characterization of Interactions on Transporters. TRANSPORTERS IN DRUG DEVELOPMENT 2013. [DOI: 10.1007/978-1-4614-8229-1_4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Fujita M, Hines CS, Zoghbi SS, Mallinger AG, Dickstein LP, Liow JS, Zhang Y, Pike VW, Drevets WC, Innis RB, Zarate CA. Downregulation of brain phosphodiesterase type IV measured with 11C-(R)-rolipram positron emission tomography in major depressive disorder. Biol Psychiatry 2012; 72:548-54. [PMID: 22677471 PMCID: PMC3438357 DOI: 10.1016/j.biopsych.2012.04.030] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 03/30/2012] [Accepted: 04/18/2012] [Indexed: 02/07/2023]
Abstract
BACKGROUND Phosphodiesterase type IV (PDE4), an important component of the cyclic adenosine monophosphate (cAMP) cascade, selectively metabolizes cAMP in the brain to the inactive monophosphate. Basic studies suggest that PDE4 mediates the effects of several antidepressants. This study sought to quantify the binding of 11C-(R)-rolipram, a PDE4 inhibitor, as an indirect measure of this enzyme's activity in the brain of individuals with major depressive disorder (MDD) compared with healthy control subjects. METHODS 11C-(R)-Rolipram brain positron emission tomography scans were performed in 28 unmedicated MDD subjects and 25 age- and gender-matched healthy control subjects. Patients were moderately depressed and about one half were treatment-naive. 11C-(R)-Rolipram binding in the brain was measured using arterial 11C-(R)-rolipram levels to correct for the influence of cerebral blood flow. RESULTS Major depressive disorder subjects showed a widespread, approximately 20% reduction in 11C-(R)-rolipram binding (p = .002), which was not caused by different volumes of gray matter. Decreased rolipram binding of similar magnitudes was observed in most brain areas. Rolipram binding did not correlate with the severity of depressive or anxiety symptoms. CONCLUSIONS This study is the first to demonstrate that brain levels of PDE4, a critical enzyme that regulates cAMP, are decreased in unmedicated individuals with MDD in vivo. These results are in line with human postmortem and rodent studies demonstrating downregulation of the cAMP cascade in MDD and support the hypothesis that agents such as PDE4 inhibitors, which increase activity within the cAMP cascade, may have antidepressant effects.
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Affiliation(s)
- Masahiro Fujita
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892-1026, USA.
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Delivery of P-glycoprotein substrates using chemosensitizers and nanotechnology for selective and efficient therapeutic outcomes. J Control Release 2012; 161:50-61. [DOI: 10.1016/j.jconrel.2012.04.034] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 04/17/2012] [Accepted: 04/20/2012] [Indexed: 12/13/2022]
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O'Brien FE, Dinan TG, Griffin BT, Cryan JF. Interactions between antidepressants and P-glycoprotein at the blood-brain barrier: clinical significance of in vitro and in vivo findings. Br J Pharmacol 2012; 165:289-312. [PMID: 21718296 DOI: 10.1111/j.1476-5381.2011.01557.x] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The drug efflux pump P-glycoprotein (P-gp) plays an important role in the function of the blood-brain barrier by selectively extruding certain endogenous and exogenous molecules, thus limiting the ability of its substrates to reach the brain. Emerging evidence suggests that P-gp may restrict the uptake of several antidepressants into the brain, thus contributing to the poor success rate of current antidepressant therapies. Despite some inconsistency in the literature, clinical investigations of potential associations between functional single nucleotide polymorphisms in ABCB1, the gene which encodes P-gp, and antidepressant response have highlighted a potential link between P-gp function and treatment-resistant depression (TRD). Therefore, co-administration of P-gp inhibitors with antidepressants to patients who are refractory to antidepressant therapy may represent a novel therapeutic approach in the management of TRD. Furthermore, certain antidepressants inhibit P-gp in vitro, and it has been hypothesized that inhibition of P-gp by such antidepressant drugs may play a role in their therapeutic action. The present review summarizes the available in vitro, in vivo and clinical data pertaining to interactions between antidepressant drugs and P-gp, and discusses the potential relevance of these interactions in the treatment of depression.
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Affiliation(s)
- Fionn E O'Brien
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
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Mairinger S, Erker T, Muller M, Langer O. PET and SPECT radiotracers to assess function and expression of ABC transporters in vivo. Curr Drug Metab 2012; 12:774-92. [PMID: 21434859 DOI: 10.2174/138920011798356980] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Revised: 01/26/2011] [Accepted: 01/28/2011] [Indexed: 11/22/2022]
Abstract
Adenosine triphosphate-binding cassette (ABC) transporters, such as P-glycoprotein (Pgp, ABCB1), breast cancer resistance protein (BCRP, ABCG2) and multidrug resistance-associated proteins (MRPs) are expressed in high concentrations at various physiological barriers (e.g. blood-brain barrier, blood-testis barrier, blood-tumor barrier), where they impede the tissue accumulation of various drugs by active efflux transport. Changes in ABC transporter expression and function are thought to be implicated in various diseases, such as cancer, epilepsy, Alzheimer's and Parkinson's disease. The availability of a non-invasive imaging method which allows for measuring ABC transporter function or expression in vivo would be of great clinical use in that it could facilitate the identification of those patients that would benefit from treatment with ABC transporter modulating drugs. To date three different kinds of imaging probes have been described to measure ABC transporters in vivo: i) radiolabelled transporter substrates ii) radiolabelled transporter inhibitors and iii) radiolabelled prodrugs which are enzymatically converted into transporter substrates in the organ of interest (e.g. brain). The design of new imaging probes to visualize efflux transporters is inter alia complicated by the overlapping substrate recognition pattern of different ABC transporter types. The present article will describe currently available ABC transporter radiotracers for positron emission tomography (PET) and single-photon emission computed tomography (SPECT) and critically discuss strengths and limitations of individual probes and their potential clinical applications.
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Affiliation(s)
- Severin Mairinger
- Health and Environment Department, Molecular Medicine, AIT Austrian Institute of Technology GmbH, 2444 Seibersdorf, Austria
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Mason BL, Thomas SA, Lightman SL, Pariante CM. Desipramine treatment has minimal effects on the brain accumulation of glucocorticoids in P-gp-deficient and wild-type mice. Psychoneuroendocrinology 2011; 36:1351-60. [PMID: 21481537 PMCID: PMC3179986 DOI: 10.1016/j.psyneuen.2011.03.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 03/15/2011] [Accepted: 03/16/2011] [Indexed: 12/18/2022]
Abstract
Hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis in patients with depression can be reduced by antidepressants, which are thought to improve endogenous glucocorticoid-mediated negative feedback. A proportion of peripherally released glucocorticoids need to enter brain tissue, protected by the blood-brain barrier (BBB), in order to achieve this negative feedback effect at the level of the central nervous systems (CNS). The multidrug resistance transporter P-glycoprotein (P-gp) has been shown to actively transport glucocorticoid hormones and has been implicated in the regulation of glucocorticoid access to the CNS. Using an in situ brain/choroid plexus perfusion method, we tested the hypothesis that the antidepressant desipramine increases glucocorticoid accumulation in the mouse brain by inhibiting P-gp, following either chronic treatment (8 days, 20 mg/kg/day, IP) or acute administration (20 min brain perfusion in the presence of either 0.9 μM or 10 μM desipramine). Contrary to our hypothesis, chronic treatment with desipramine did not affect the accumulation of [³H]dexamethasone in any sample compared to saline-treated mice. Acute desipramine had limited and variable effects on glucocorticoid accumulation in the CNS, with accumulation of [³H]dexamethasone increased in the cerebellum, accumulation of [³H]cortisol reduced in the frontal cortex, hypothalamus, and cerebellum, and accumulation of [³H]corticosterone (the endogenous glucocorticoid in rodents) not affected. Overall, under the conditions tested, these results do not support the hypothesis that treatment with desipramine can inhibit P-gp at the BBB and subsequently increase the accumulation of glucocorticoids in the brain.
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Affiliation(s)
- Brittany L Mason
- Institute of Pharmaceutical Science, King's College London, London, UK.
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Further evidence for an immediate antidepressant action of intracerebral drug administration in a model of chronic depression. Int J Neuropsychopharmacol 2011; 14:691-6. [PMID: 20875221 DOI: 10.1017/s1461145710001161] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
This study was designed to replicate an earlier finding of a rapid acute therapeutic action of intracerebrally administered antidepressant in chronically depressed rodents. The effects of acute fourth ventricular (ivt.) injections were compared to those of acute peripheral (i.p.) injections of desipramine (DMI) in mice subjected to repeated open-space forced swim. In confirmation, it was found that a single ivt. injection of a low (3 nmol) but not high (30 nmol) dose immediately reversed the immobility and inactivity of the model whereas acute i.p. administration was without effect up to 30 mg/kg. The repeated forced swim stress was also found to significantly reduce the net accumulation of DMI in the brain but not liver after a single i.p. injection of a moderate dose (10 mg/kg). The results suggest that stress-induced alterations of regional drug uptake or metabolism in the CNS may contribute to the therapeutic lag for antidepressants and other compounds in disorders with high distress.
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Regional P-glycoprotein activity and inhibition at the human blood-brain barrier as imaged by positron emission tomography. Clin Pharmacol Ther 2010; 87:579-85. [PMID: 20336065 DOI: 10.1038/clpt.2010.11] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We used positron emission tomography (PET) to evaluate the contribution of P-glycoprotein (P-gp), present at the human blood-brain barrier (BBB), to regional drug distribution in the brain. Eleven healthy volunteers underwent PET imaging with [(11)C]-verapamil before and during cyclosporine A infusion. Regional P-gp inhibition was expressed as cyclosporine A-induced percentage change in the distributional clearance of verapamil (K(1)) in the brain, normalized to the regional blood flow (rCBF). K(1) estimates were similar across gray-matter regions of the brain and lower in the white matter regions, but all these estimates were considerably lower than rCBF. Normalization of K(1) by rCBF diminished the differences in estimates related to gray matter and white matter. In contrast, the K(1) for the pituitary, which is situated outside the BBB, approximated the rCBF. The magnitude of P-gp inhibition was comparable across BBB-protected brain structures. Our results indicate that P-gp and its inhibition equally affect the distribution of drugs (and therefore their neuro-efficacy and toxicity) in the various brain regions protected by the BBB.
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Bauer M, Karch R, Neumann F, Abrahim A, Wagner CC, Kletter K, Müller M, Zeitlinger M, Langer O. Age dependency of cerebral P-gp function measured with (R)-[11C]verapamil and PET. Eur J Clin Pharmacol 2009; 65:941-6. [PMID: 19655132 DOI: 10.1007/s00228-009-0709-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Accepted: 07/21/2009] [Indexed: 11/30/2022]
Abstract
PURPOSE The aim of this study was to assess the influence of age on the functional activity of the multidrug efflux transporter P-glycoprotein (P-gp) at the human blood-brain barrier. METHODS Seven young (mean age: 27 +/- 4 years) and six elderly (mean age: 69 +/- 9 years) healthy volunteers underwent dynamic (R)-[(11)C]verapamil (VPM) positron emission tomography (PET) scans and arterial blood sampling. Parametric distribution volume (DV) images were generated using Logan linearisation, and age groups were compared with statistical parametric mapping (SPM). Brain regions that SPM analysis had shown to be most affected by age were analysed by a region of interest (ROI)-based approach using a maximum probability brain atlas, before and after partial volume correction (PVC). RESULTS SPM analysis revealed significant clusters of DV increases in cerebellum, temporal and frontal lobe of elderly compared to younger subjects. In the ROI-based analysis, elderly subjects showed significant DV increases in amygdala (+30%), insula (+26%) and cerebellum (+25%) before PVC, and in insula (+33%) after PVC. CONCLUSIONS Increased VPM DV values in the brains of elderly subjects suggest a decrease in cerebral P-gp function with increasing age.
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Affiliation(s)
- Martin Bauer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
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