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Lopresti BJ, Royse SK, Mathis CA, Tollefson SA, Narendran R. Beyond monoamines: I. Novel targets and radiotracers for Positron emission tomography imaging in psychiatric disorders. J Neurochem 2023; 164:364-400. [PMID: 35536762 DOI: 10.1111/jnc.15615] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/05/2022] [Accepted: 04/06/2022] [Indexed: 10/18/2022]
Abstract
With the emergence of positron emission tomography (PET) in the late 1970s, psychiatry had access to a tool capable of non-invasive assessment of human brain function. Early applications in psychiatry focused on identifying characteristic brain blood flow and metabolic derangements using radiotracers such as [15 O]H2 O and [18 F]FDG. Despite the success of these techniques, it became apparent that more specific probes were needed to understand the neurochemical bases of psychiatric disorders. The first neurochemical PET imaging probes targeted sites of action of neuroleptic (dopamine D2 receptors) and psychoactive (serotonin receptors) drugs. Based on the centrality of monoamine dysfunction in psychiatric disorders and the measured success of monoamine-enhancing drugs in treating them, the next 30 years witnessed the development of an armamentarium of PET radiopharmaceuticals and imaging methodologies for studying monoamines. Continued development of monoamine-enhancing drugs over this time however was less successful, realizing only modest gains in efficacy and tolerability. As patent protection for many widely prescribed and profitable psychiatric drugs lapsed, drug development pipelines shifted away from monoamines in search of novel targets with the promises of improved efficacy, or abandoned altogether. Over this period, PET radiopharmaceutical development activities closely paralleled drug development priorities resulting in the development of new PET imaging agents for non-monoamine targets. Part one of this review will briefly survey novel PET imaging targets with relevance to the field of psychiatry, which include the metabotropic glutamate receptor type 5 (mGluR5), purinergic P2 X7 receptor, type 1 cannabinoid receptor (CB1 ), phosphodiesterase 10A (PDE10A), and describe radiotracers developed for these and other targets that have matured to human subject investigations. Current limitations of the targets and techniques will also be discussed.
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Affiliation(s)
- Brian J Lopresti
- Departments of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Sarah K Royse
- Departments of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Chester A Mathis
- Departments of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Savannah A Tollefson
- Departments of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Rajesh Narendran
- Departments of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,Departments of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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2
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Rosenberg AJ, Cheung Y, Liu F, Peterson TE, Silverman J, Considine CM, Claassen DO. Automated Synthesis of
(R)
‐[
18
F F]MH.MZ on the iPhase Flexlab Reaction Platform. J Labelled Comp Radiopharm 2022; 65:223-229. [DOI: 10.1002/jlcr.3975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/23/2022] [Accepted: 04/26/2022] [Indexed: 11/11/2022]
Affiliation(s)
- Adam J. Rosenberg
- Vanderbilt University Institute for Imaging Science Vanderbilt University Medical Center Nashville Tennessee USA
- Department of Radiology and Radiological Sciences Vanderbilt University Medical Center Nashville Tennessee USA
| | - Yiu‐Yin Cheung
- Vanderbilt University Institute for Imaging Science Vanderbilt University Medical Center Nashville Tennessee USA
| | - Fei Liu
- Vanderbilt University Institute for Imaging Science Vanderbilt University Medical Center Nashville Tennessee USA
| | - Todd E. Peterson
- Vanderbilt University Institute for Imaging Science Vanderbilt University Medical Center Nashville Tennessee USA
- Department of Radiology and Radiological Sciences Vanderbilt University Medical Center Nashville Tennessee USA
| | - James Silverman
- Department of Neurology Vanderbilt University Medical Center Nashville TN USA
| | - Ciaran M. Considine
- Department of Neurology Vanderbilt University Medical Center Nashville TN USA
| | - Daniel O. Claassen
- Department of Neurology Vanderbilt University Medical Center Nashville TN USA
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Bidesi NSR, Vang Andersen I, Windhorst AD, Shalgunov V, Herth MM. The role of neuroimaging in Parkinson's disease. J Neurochem 2021; 159:660-689. [PMID: 34532856 PMCID: PMC9291628 DOI: 10.1111/jnc.15516] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 09/09/2021] [Accepted: 09/10/2021] [Indexed: 11/29/2022]
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder that affects millions of people worldwide. Two hallmarks of PD are the accumulation of alpha-synuclein and the loss of dopaminergic neurons in the brain. There is no cure for PD, and all existing treatments focus on alleviating the symptoms. PD diagnosis is also based on the symptoms, such as abnormalities of movement, mood, and cognition observed in the patients. Molecular imaging methods such as magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT), and positron emission tomography (PET) can detect objective alterations in the neurochemical machinery of the brain and help diagnose and study neurodegenerative diseases. This review addresses the application of functional MRI, PET, and SPECT in PD patients. We provide an overview of the imaging targets, discuss the rationale behind target selection, the agents (tracers) with which the imaging can be performed, and the main findings regarding each target's state in PD. Molecular imaging has proven itself effective in supporting clinical diagnosis of PD and has helped reveal that PD is a heterogeneous disorder, which has important implications for the development of future therapies. However, the application of molecular imaging for early diagnosis of PD or for differentiation between PD and atypical parkinsonisms has remained challenging. The final section of the review is dedicated to new imaging targets with which one can detect the PD-related pathological changes upstream from dopaminergic degeneration. The foremost of those targets is alpha-synuclein. We discuss the progress of tracer development achieved so far and challenges on the path toward alpha-synuclein imaging in humans.
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Affiliation(s)
- Natasha S R Bidesi
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Ida Vang Andersen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Albert D Windhorst
- Radiology and Nuclear Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Vladimir Shalgunov
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Matthias M Herth
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen, Denmark
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Opposite alterations of 5-HT 2A receptor brain density in subjects with schizophrenia: relevance of radiotracers pharmacological profile. Transl Psychiatry 2021; 11:302. [PMID: 34016955 PMCID: PMC8137947 DOI: 10.1038/s41398-021-01430-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 04/26/2021] [Accepted: 05/05/2021] [Indexed: 02/04/2023] Open
Abstract
The status of serotonin 5-HT2A receptors (5-HT2ARs) in schizophrenia has been controversial. In vivo positron emission tomography neuroimaging and in vitro post-mortem binding studies have reported conflicting results about 5-HT2AR density. Radiotracers bind different receptor conformations depending on their agonist, antagonist or inverse agonist properties. This study investigates 5-HT2AR density in the post-mortem prefrontal cortex from subjects with schizophrenia and controls using three radiotracers with a different pharmacological profile. The specific binding parameters of the inverse agonist [18F]altanserin, the agonist [3H]lysergic acid diethylamide (LSD) and the antagonist [3H]MDL100907 to brain cortex membranes from 20 subjects with schizophrenia and 20 individually matched controls were evaluated under similar methodological conditions. Ten schizophrenia subjects were antipsychotic-free at death. Saturation curve analyses were performed by non-linear regression to obtain a maximal density of binding sites (Bmax) and the affinity of the respective radiotracers (Kd). In schizophrenia subjects, 5-HT2AR density was decreased when quantified by [18F]altanserin binding, whereas increased when evaluated by [3H]LSD binding. However, [3H]MDL100907 binding was unaltered. A slight loss of affinity (higher Kd) was observed exclusively in [3H]LSD binding. The findings were more evident in antipsychotic-free subjects than in antipsychotic-treated subjects. In conclusion, a higher proportion of the 5-HT2AR-active functional conformation, which is rather identified by agonist radiotracers, was observed in schizophrenia patients. A consequent reduction of the inactive 5-HT2AR conformation, which is preferentially identified by inverse agonist radiotracers, was also obtained. Antagonist radiotracers do not distinguish between molecular conformations of the receptor, and accordingly, the absence of changes was shown. These results are compatible with the proposed increased functional activity of brain cortical 5-HT2ARs in schizophrenia.
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García-Bea A, Miranda-Azpiazu P, Muguruza C, Marmolejo-Martinez-Artesero S, Diez-Alarcia R, Gabilondo AM, Callado LF, Morentin B, González-Maeso J, Meana JJ. Serotonin 5-HT 2A receptor expression and functionality in postmortem frontal cortex of subjects with schizophrenia: Selective biased agonism via G αi1-proteins. Eur Neuropsychopharmacol 2019; 29:1453-1463. [PMID: 31734018 DOI: 10.1016/j.euroneuro.2019.10.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 10/17/2019] [Accepted: 10/29/2019] [Indexed: 12/20/2022]
Abstract
Serotonin 5-HT2A receptors (5-HT2ARs) have been implicated in schizophrenia. However, postmortem studies on 5-HT2ARs expression and functionality in schizophrenia are scarce. The 5-HT2AR mRNA and immunoreactive protein expression were evaluated in postmortem tissue from dorsolateral prefrontal cortex (DLPFC) of antipsychotic-free (n = 18) and antipsychotic-treated (n = 9) subjects with schizophrenia, and matched controls (n = 27). Functional coupling of 5-HT2AR to G-proteins was tested by measuring the activation induced by the agonist (±)-2,5-dimethoxy-4-iodoamphetamine hydrochloride ((±)DOI) in antibody-capture [35S]GTPγS scintillation proximity assays (SPA). In antipsychotic-free schizophrenia subjects, 5-HT2AR mRNA expression and protein immunoreactivity in total homogenates was similar to controls. In contrast, in antipsychotic-treated schizophrenia subjects, lower mRNA expression (60±9% vs controls) and a trend to reduced protein immunoreactivity (86±5% vs antipsychotic-free subjects) just in membrane-enriched fractions was observed. [35S]GTPγS SPA revealed a significant ~6% higher stimulation of Gαi1-protein by (±)DOI in schizophrenia, whereas activation of the canonical Gαq/11-protein pathway by (±)DOI remained unchanged. Expression of Gαi1- and Gαq/11-proteins did not differ between groups. Accordingly, in rats chronically treated with clozapine, but not with haloperidol, a 30-40% reduction was observed in 5-HT2AR mRNA expression, 5-HT2AR protein immunoreactivity and [3H]ketanserin binding in brain cortical membranes. Overall, the data suggest a supersensitive 5-HT2AR signaling through inhibitory Gαi1-proteins in schizophrenia. Together with previous results, a dysfunctional pro-hallucinogenic agonist-sensitive 5-HT2AR conformation in postmortem DLPFC of subjects with schizophrenia is proposed. Atypical antipsychotic treatment would contribute to counterbalance this 5-HT2AR supersensitivity by reducing receptor expression.
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Affiliation(s)
- Aintzane García-Bea
- Department of Pharmacology, University of the Basque Country UPV/EHU, 48940 Leioa, Bizkaia, Spain; Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Spain
| | - Patricia Miranda-Azpiazu
- Department of Pharmacology, University of the Basque Country UPV/EHU, 48940 Leioa, Bizkaia, Spain; Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Spain
| | - Carolina Muguruza
- Department of Pharmacology, University of the Basque Country UPV/EHU, 48940 Leioa, Bizkaia, Spain; Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Spain
| | | | - Rebeca Diez-Alarcia
- Department of Pharmacology, University of the Basque Country UPV/EHU, 48940 Leioa, Bizkaia, Spain; Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Spain; Biocruces Bizkaia Health Research Institute, Spain
| | - Ane M Gabilondo
- Department of Pharmacology, University of the Basque Country UPV/EHU, 48940 Leioa, Bizkaia, Spain; Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Spain; Biocruces Bizkaia Health Research Institute, Spain
| | - Luis F Callado
- Department of Pharmacology, University of the Basque Country UPV/EHU, 48940 Leioa, Bizkaia, Spain; Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Spain; Biocruces Bizkaia Health Research Institute, Spain
| | - Benito Morentin
- Biocruces Bizkaia Health Research Institute, Spain; Basque Institute of Legal Medicine, Spain
| | - Javier González-Maeso
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, VA, USA
| | - J Javier Meana
- Department of Pharmacology, University of the Basque Country UPV/EHU, 48940 Leioa, Bizkaia, Spain; Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Spain; Biocruces Bizkaia Health Research Institute, Spain.
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Pauwelyn G, Vlerick L, Dockx R, Verhoeven J, Dobbeleir A, Bosmans T, Peremans K, Vanhove C, Polis I, De Vos F. Kinetic analysis of [ 18F] altanserin bolus injection in the canine brain using PET imaging. BMC Vet Res 2019; 15:415. [PMID: 31752848 PMCID: PMC6873736 DOI: 10.1186/s12917-019-2165-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 11/06/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Currently, [18F] altanserin is the most frequently used PET-radioligand for serotonin2A (5-HT2A) receptor imaging in the human brain but has never been validated in dogs. In vivo imaging of this receptor in the canine brain could improve diagnosis and therapy of several behavioural disorders in dogs. Furthermore, since dogs are considered as a valuable animal model for human psychiatric disorders, the ability to image this receptor in dogs could help to increase our understanding of the pathophysiology of these diseases. Therefore, five healthy laboratory beagles underwent a 90-min dynamic PET scan with arterial blood sampling after [18F] altanserin bolus injection. Compartmental modelling using metabolite corrected arterial input functions was compared with reference tissue modelling with the cerebellum as reference region. RESULTS The distribution of [18F] altanserin in the canine brain corresponded well to the distribution of 5-HT2A receptors in human and rodent studies. The kinetics could be best described by a 2-Tissue compartment (2-TC) model. All reference tissue models were highly correlated with the 2-TC model, indicating compartmental modelling can be replaced by reference tissue models to avoid arterial blood sampling. CONCLUSIONS This study demonstrates that [18F] altanserin PET is a reliable tool to visualize and quantify the 5-HT2A receptor in the canine brain.
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Affiliation(s)
- Glenn Pauwelyn
- Laboratory of Radiopharmacy, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium.
| | - Lise Vlerick
- Small animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Robrecht Dockx
- Small animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.,Department of Psychiatry and Medical Psychology, Ghent University, Ghent, Belgium
| | - Jeroen Verhoeven
- Laboratory of Radiopharmacy, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium
| | - Andre Dobbeleir
- Small animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.,Department of Nuclear Medicine, Ghent University Hospital, Ghent, Belgium
| | - Tim Bosmans
- Small animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Kathelijne Peremans
- Small animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Christian Vanhove
- Institute Biomedical Technology - Medisip - Infinity, Ghent University, Ghent, Belgium
| | - Ingeborgh Polis
- Small animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Filip De Vos
- Laboratory of Radiopharmacy, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium
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