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Lee N, Choi JY, Ryu YH. The development status of PET radiotracers for evaluating neuroinflammation. Nucl Med Mol Imaging 2024; 58:160-176. [PMID: 38932754 PMCID: PMC11196502 DOI: 10.1007/s13139-023-00831-4] [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: 10/11/2023] [Revised: 11/16/2023] [Accepted: 12/05/2023] [Indexed: 06/28/2024] Open
Abstract
Neuroinflammation is associated with the pathophysiologies of neurodegenerative and psychiatric disorders. Evaluating neuroinflammation using positron emission tomography (PET) plays an important role in the early diagnosis and determination of proper treatment of brain diseases. To quantify neuroinflammatory responses in vivo, many PET tracers have been developed using translocator proteins, imidazole-2 binding site, cyclooxygenase, monoamine oxidase-B, adenosine, cannabinoid, purinergic P2X7, and CSF-1 receptors as biomarkers. In this review, we introduce the latest developments in PET tracers that can image neuroinflammation, focusing on clinical trials, and further consider their current implications.
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Affiliation(s)
- Namhun Lee
- Division of Applied RI, Korea Institute of Radiological & Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 01812 Korea
| | - Jae Yong Choi
- Division of Applied RI, Korea Institute of Radiological & Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 01812 Korea
- Radiological and Medico-Oncological Sciences, University of Science and Technology (UST), Seoul, Korea
| | - Young Hoon Ryu
- Department of Nuclear Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
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Yang T, Zheng W, Cheng X, Chen H, Jiang Z, Yu Z, Zhang L, Xie Y, Du L, Ge X, Zhang J, Yuan L, Liu Y, Wu Z. 18F-Labeled PET Tracers Specific for Adenosine A 2A Receptor: Design, Synthesis, and Biological Evaluation. ACS Chem Neurosci 2024; 15:1286-1297. [PMID: 38457777 DOI: 10.1021/acschemneuro.4c00066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2024] Open
Abstract
By modifying the structures of targeted A2AR antagonists and tracers, novel compounds 3, 7a, 9, 12c, and BIBD-399 were designed and synthesized. In vitro inhibition experiments demonstrated that 3, 12c, and BIBD-399 have high affinity for A2AR. [18F]3 and [18F]BIBD-399 were successfully synthesized. In terms of biological distribution, the brain uptake of [18F]MNI-444 exhibits greater than that of [18F]3 and [18F]BIBD-399. PET imaging shows that [18F]3 is off-target in the brain, while [18F]BIBD-399 and [18F]MNI-444 can be specifically imaged in regions with high A2AR expression. Differently, [18F]BIBD-399 could quickly reach equilibrium in the targeted region within 10 min after administration, while [18F]MNI-444 shows a slowly increasing trend within 2 h of administration. [18F]BIBD-399 is mainly metabolized by the liver and kidney, and there is no obvious defluorination in vivo. Additional in vitro autoradiography showed that the striatal signals of [18F]BIBD-399 and [18F]MNI-444 were inhibited by the A2AR antagonist SCH442416 but not by the A1R antagonist DPCPX, demonstrating the high A2AR binding specificity of [18F]BIBD-399. Molecular docking further confirms the high affinity of MNI-444 and BIBD-399 for A2AR. Further tMCAo imaging showed that [18F]BIBD-399 can sensitively distinguish between infarcted and noninfarcted sides, a capability not observed with [18F]MNI-444. Given its pharmacokinetic properties and the ability to identify lesion regions, [18F]BIBD-399 has potential advantages in monitoring A2AR changes, meriting further clinical investigation.
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Affiliation(s)
- Tingyu Yang
- School of Pharmaceutical Science, Capital Medical University, Beijing 100069, China
| | - Wei Zheng
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Xuebo Cheng
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Hualong Chen
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Zeng Jiang
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Ziyue Yu
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Lu Zhang
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Yi Xie
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Lianjie Du
- School of Pharmaceutical Science, Capital Medical University, Beijing 100069, China
| | - Xuan Ge
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Jiahuai Zhang
- Center for Clinical Laboratory, Capital Medical University, Beijing 100069, China
| | - Leilei Yuan
- Department of Nuclear Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, China
| | - Yajing Liu
- School of Pharmaceutical Science, Capital Medical University, Beijing 100069, China
| | - Zehui Wu
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing 100069, China
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Singh P, Singh D, Srivastava P, Mishra G, Tiwari AK. Evaluation of advanced, pathophysiologic new targets for imaging of CNS. Drug Dev Res 2023; 84:484-513. [PMID: 36779375 DOI: 10.1002/ddr.22040] [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: 10/23/2022] [Revised: 12/12/2022] [Accepted: 12/31/2022] [Indexed: 02/14/2023]
Abstract
The inadequate information about the in vivo pathological, physiological, and neurological impairments, as well as the absence of in vivo tools for assessing brain penetrance and the efficiency of newly designed drugs, has hampered the development of new techniques for the treatment for variety of new central nervous system (CNS) diseases. The searching sites such as Science Direct and PubMed were used to find out the numerous distinct tracers across 16 CNS targets including tau, synaptic vesicle glycoprotein, the adenosine 2A receptor, the phosphodiesterase enzyme PDE10A, and the purinoceptor, among others. Among the most encouraging are [18 F]FIMX for mGluR imaging, [11 C]Martinostat for Histone deacetylase, [18 F]MNI-444 for adenosine 2A imaging, [11 C]ER176 for translocator protein, and [18 F]MK-6240 for tau imaging. We also reviewed the findings for each tracer's features and potential for application in CNS pathophysiology and therapeutic evaluation investigations, including target specificity, binding efficacy, and pharmacokinetic factors. This review aims to present a current evaluation of modern positron emission tomography tracers for CNS targets, with a focus on recent advances for targets that have newly emerged for imaging in humans.
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Affiliation(s)
- Priya Singh
- Department of Chemistry, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh, India
| | - Deepika Singh
- Department of Chemistry, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh, India
| | - Pooja Srivastava
- Division of Cyclotron and Radiopharmaceuticals Sciences, Institute of Nuclear Medicine and Allied Sciences, Delhi, India
| | - Gauri Mishra
- Department of Zoology, Swami Shraddhananad College, University of Delhi, Alipur, Delhi, India
| | - Anjani K Tiwari
- Department of Chemistry, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh, India
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4
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Rose R, Mitchell E, Van Der Graaf P, Takaichi D, Hosogi J, Geerts H. A quantitative systems pharmacology model for simulating OFF-Time in augmentation trials for Parkinson’s disease: application to preladenant. J Pharmacokinet Pharmacodyn 2022; 49:593-606. [DOI: 10.1007/s10928-022-09825-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 09/13/2022] [Indexed: 11/29/2022]
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Crișan G, Moldovean-Cioroianu NS, Timaru DG, Andrieș G, Căinap C, Chiș V. Radiopharmaceuticals for PET and SPECT Imaging: A Literature Review over the Last Decade. Int J Mol Sci 2022; 23:ijms23095023. [PMID: 35563414 PMCID: PMC9103893 DOI: 10.3390/ijms23095023] [Citation(s) in RCA: 61] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 04/23/2022] [Accepted: 04/28/2022] [Indexed: 02/04/2023] Open
Abstract
Positron emission tomography (PET) uses radioactive tracers and enables the functional imaging of several metabolic processes, blood flow measurements, regional chemical composition, and/or chemical absorption. Depending on the targeted processes within the living organism, different tracers are used for various medical conditions, such as cancer, particular brain pathologies, cardiac events, and bone lesions, where the most commonly used tracers are radiolabeled with 18F (e.g., [18F]-FDG and NA [18F]). Oxygen-15 isotope is mostly involved in blood flow measurements, whereas a wide array of 11C-based compounds have also been developed for neuronal disorders according to the affected neuroreceptors, prostate cancer, and lung carcinomas. In contrast, the single-photon emission computed tomography (SPECT) technique uses gamma-emitting radioisotopes and can be used to diagnose strokes, seizures, bone illnesses, and infections by gauging the blood flow and radio distribution within tissues and organs. The radioisotopes typically used in SPECT imaging are iodine-123, technetium-99m, xenon-133, thallium-201, and indium-111. This systematic review article aims to clarify and disseminate the available scientific literature focused on PET/SPECT radiotracers and to provide an overview of the conducted research within the past decade, with an additional focus on the novel radiopharmaceuticals developed for medical imaging.
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Affiliation(s)
- George Crișan
- Faculty of Physics, Babeş-Bolyai University, Str. M. Kogălniceanu 1, 400084 Cluj-Napoca, Romania; (G.C.); (N.S.M.-C.); (D.-G.T.)
- Department of Nuclear Medicine, County Clinical Hospital, Clinicilor 3-5, 400006 Cluj-Napoca, Romania;
| | | | - Diana-Gabriela Timaru
- Faculty of Physics, Babeş-Bolyai University, Str. M. Kogălniceanu 1, 400084 Cluj-Napoca, Romania; (G.C.); (N.S.M.-C.); (D.-G.T.)
| | - Gabriel Andrieș
- Department of Nuclear Medicine, County Clinical Hospital, Clinicilor 3-5, 400006 Cluj-Napoca, Romania;
| | - Călin Căinap
- The Oncology Institute “Prof. Dr. Ion Chiricuţă”, Republicii 34-36, 400015 Cluj-Napoca, Romania;
| | - Vasile Chiș
- Faculty of Physics, Babeş-Bolyai University, Str. M. Kogălniceanu 1, 400084 Cluj-Napoca, Romania; (G.C.); (N.S.M.-C.); (D.-G.T.)
- Institute for Research, Development and Innovation in Applied Natural Sciences, Babeș-Bolyai University, Str. Fântânele 30, 400327 Cluj-Napoca, Romania
- Correspondence:
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Gündel D, Toussaint M, Lai TH, Deuther-Conrad W, Cumming P, Schröder S, Teodoro R, Moldovan RP, Pan-Montojo F, Sattler B, Kopka K, Sabri O, Brust P. Quantitation of the A2A Adenosine Receptor Density in the Striatum of Mice and Pigs with [18F]FLUDA by Positron Emission Tomography. Pharmaceuticals (Basel) 2022; 15:ph15050516. [PMID: 35631343 PMCID: PMC9146919 DOI: 10.3390/ph15050516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/14/2022] [Accepted: 04/19/2022] [Indexed: 12/10/2022] Open
Abstract
The cerebral expression of the A2A adenosine receptor (A2AAR) is altered in neurodegenerative diseases such as Parkinson’s (PD) and Huntington’s (HD) diseases, making these receptors an attractive diagnostic and therapeutic target. We aimed to further investigate the pharmacokinetic properties in the brain of our recently developed A2AAR–specific antagonist radiotracer [18F]FLUDA. For this purpose, we retrospectively analysed dynamic PET studies of healthy mice and rotenone–treated mice, and conducted dynamic PET studies with healthy pigs. We performed analysis of mouse brain time–activity curves to calculate the mean residence time (MRT) by non–compartmental analysis, and the binding potential (BPND) of [18F]FLUDA using the simplified reference tissue model (SRTM). For the pig studies, we performed a Logan graphical analysis to calculate the radiotracer distribution volume (VT) at baseline and under blocking conditions with tozadenant. The MRT of [18F]FLUDA in the striatum of mice was decreased by 30% after treatment with the A2AAR antagonist istradefylline. Mouse results showed the highest BPND (3.9 to 5.9) in the striatum. SRTM analysis showed a 20% lower A2AAR availability in the rotenone–treated mice compared to the control–aged group. Tozadenant treatment significantly decreased the VT (14.6 vs. 8.5 mL · g−1) and BPND values (1.3 vs. 0.3) in pig striatum. This study confirms the target specificity and a high BPND of [18F]FLUDA in the striatum. We conclude that [18F]FLUDA is a suitable tool for the non–invasive quantitation of altered A2AAR expression in neurodegenerative diseases such as PD and HD, by PET.
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Affiliation(s)
- Daniel Gündel
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz–Zentrum Dresden–Rossendorf, 04308 Leipzig, Germany; (M.T.); (T.H.L.); (W.D.-C.); (R.T.); (R.-P.M.); (K.K.); (P.B.)
- Correspondence: ; Tel.: +49-341-234179-4615
| | - Magali Toussaint
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz–Zentrum Dresden–Rossendorf, 04308 Leipzig, Germany; (M.T.); (T.H.L.); (W.D.-C.); (R.T.); (R.-P.M.); (K.K.); (P.B.)
| | - Thu Hang Lai
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz–Zentrum Dresden–Rossendorf, 04308 Leipzig, Germany; (M.T.); (T.H.L.); (W.D.-C.); (R.T.); (R.-P.M.); (K.K.); (P.B.)
- Department of Research and Development, ROTOP Pharmaka Ltd., 01328 Dresden, Germany;
| | - Winnie Deuther-Conrad
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz–Zentrum Dresden–Rossendorf, 04308 Leipzig, Germany; (M.T.); (T.H.L.); (W.D.-C.); (R.T.); (R.-P.M.); (K.K.); (P.B.)
| | - Paul Cumming
- Department of Nuclear Medicine, Bern University Hospital, 3010 Bern, Switzerland;
- School of Psychology and Counselling, Queensland University of Technology, Brisbane 4000, Australia
| | - Susann Schröder
- Department of Research and Development, ROTOP Pharmaka Ltd., 01328 Dresden, Germany;
| | - Rodrigo Teodoro
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz–Zentrum Dresden–Rossendorf, 04308 Leipzig, Germany; (M.T.); (T.H.L.); (W.D.-C.); (R.T.); (R.-P.M.); (K.K.); (P.B.)
- Department of Research and Development, Life Molecular Imaging GmbH, 13353 Berlin, Germany
| | - Rareş-Petru Moldovan
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz–Zentrum Dresden–Rossendorf, 04308 Leipzig, Germany; (M.T.); (T.H.L.); (W.D.-C.); (R.T.); (R.-P.M.); (K.K.); (P.B.)
| | - Francisco Pan-Montojo
- Department of Psychiatry, University Hospital Munich, Ludwig–Maximilians–Universität (LMU) Munich, 80336 Munich, Germany;
- Department of Neurology, University Hospital Munich, Ludwig–Maximilians–Universität (LMU) Munich, 81377 Munich, Germany
| | - Bernhard Sattler
- Department for Nuclear Medicine, University Hospital Leipzig, 04103 Leipzig, Germany; (B.S.); (O.S.)
| | - Klaus Kopka
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz–Zentrum Dresden–Rossendorf, 04308 Leipzig, Germany; (M.T.); (T.H.L.); (W.D.-C.); (R.T.); (R.-P.M.); (K.K.); (P.B.)
- Faculty of Chemistry and Food Chemistry, School of Science, TU Dresden, 01069 Dresden, Germany
| | - Osama Sabri
- Department for Nuclear Medicine, University Hospital Leipzig, 04103 Leipzig, Germany; (B.S.); (O.S.)
| | - Peter Brust
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz–Zentrum Dresden–Rossendorf, 04308 Leipzig, Germany; (M.T.); (T.H.L.); (W.D.-C.); (R.T.); (R.-P.M.); (K.K.); (P.B.)
- The Lübeck Institute of Experimental Dermatology, University Medical Center Schleswig–Holstein, 23562 Lübeck, Germany
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Lai TH, Toussaint M, Teodoro R, Dukić-Stefanović S, Gündel D, Ludwig FA, Wenzel B, Schröder S, Sattler B, Moldovan RP, Falkenburger BH, Sabri O, Deuther-Conrad W, Brust P. Improved in vivo PET imaging of the adenosine A 2A receptor in the brain using [ 18F]FLUDA, a deuterated radiotracer with high metabolic stability. Eur J Nucl Med Mol Imaging 2021; 48:2727-2736. [PMID: 33532910 PMCID: PMC8263428 DOI: 10.1007/s00259-020-05164-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 12/13/2020] [Indexed: 02/07/2023]
Abstract
PURPOSE The adenosine A2A receptor has emerged as a therapeutic target for multiple diseases, and thus the non-invasive imaging of the expression or occupancy of the A2A receptor has potential to contribute to diagnosis and drug development. We aimed at the development of a metabolically stable A2A receptor radiotracer and report herein the preclinical evaluation of [18F]FLUDA, a deuterated isotopologue of [18F]FESCH. METHODS [18F]FLUDA was synthesized by a two-step one-pot approach and evaluated in vitro by autoradiographic studies as well as in vivo by metabolism and dynamic PET/MRI studies in mice and piglets under baseline and blocking conditions. A single-dose toxicity study was performed in rats. RESULTS [18F]FLUDA was obtained with a radiochemical yield of 19% and molar activities of 72-180 GBq/μmol. Autoradiography proved A2A receptor-specific accumulation of [18F]FLUDA in the striatum of a mouse and pig brain. In vivo evaluation in mice revealed improved stability of [18F]FLUDA compared to that of [18F]FESCH, resulting in the absence of brain-penetrant radiometabolites. Furthermore, the radiometabolites detected in piglets are expected to have a low tendency for brain penetration. PET/MRI studies confirmed high specific binding of [18F]FLUDA towards striatal A2A receptor with a maximum specific-to-non-specific binding ratio in mice of 8.3. The toxicity study revealed no adverse effects of FLUDA up to 30 μg/kg, ~ 4000-fold the dose applied in human PET studies using [18F]FLUDA. CONCLUSIONS The new radiotracer [18F]FLUDA is suitable to detect the availability of the A2A receptor in the brain with high target specificity. It is regarded ready for human application.
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Affiliation(s)
- Thu Hang Lai
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Leipzig, Germany.
- Department of Research and Development, ROTOP Pharmaka Ltd., Dresden, Germany.
| | - Magali Toussaint
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Leipzig, Germany.
| | - Rodrigo Teodoro
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Leipzig, Germany
| | - Sladjana Dukić-Stefanović
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Leipzig, Germany
| | - Daniel Gündel
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Leipzig, Germany
| | - Friedrich-Alexander Ludwig
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Leipzig, Germany
| | - Barbara Wenzel
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Leipzig, Germany
| | - Susann Schröder
- Department of Research and Development, ROTOP Pharmaka Ltd., Dresden, Germany
| | - Bernhard Sattler
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig, Germany
| | - Rareş-Petru Moldovan
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Leipzig, Germany
| | | | - Osama Sabri
- Department of Nuclear Medicine, University Hospital Leipzig, Leipzig, Germany
| | - Winnie Deuther-Conrad
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Leipzig, Germany
| | - Peter Brust
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Leipzig, Germany
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Zarrinmayeh H, Territo PR. Purinergic Receptors of the Central Nervous System: Biology, PET Ligands, and Their Applications. Mol Imaging 2021; 19:1536012120927609. [PMID: 32539522 PMCID: PMC7297484 DOI: 10.1177/1536012120927609] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Purinergic receptors play important roles in central nervous system (CNS). These receptors are involved in cellular neuroinflammatory responses that regulate functions of neurons, microglial and astrocytes. Based on their endogenous ligands, purinergic receptors are classified into P1 or adenosine, P2X and P2Y receptors. During brain injury or under pathological conditions, rapid diffusion of extracellular adenosine triphosphate (ATP) or uridine triphosphate (UTP) from the damaged cells, promote microglial activation that result in the changes in expression of several of these receptors in the brain. Imaging of the purinergic receptors with selective Positron Emission Tomography (PET) radioligands has advanced our understanding of the functional roles of some of these receptors in healthy and diseased brains. In this review, we have accumulated a list of currently available PET radioligands of the purinergic receptors that are used to elucidate the receptor functions and participations in CNS disorders. We have also reviewed receptors lacking radiotracer, laying the foundation for future discoveries of novel PET radioligands to reveal these receptors roles in CNS disorders.
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Affiliation(s)
- Hamideh Zarrinmayeh
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Paul R Territo
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA
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Prasad K, de Vries EFJ, Elsinga PH, Dierckx RAJO, van Waarde A. Allosteric Interactions between Adenosine A 2A and Dopamine D 2 Receptors in Heteromeric Complexes: Biochemical and Pharmacological Characteristics, and Opportunities for PET Imaging. Int J Mol Sci 2021; 22:ijms22041719. [PMID: 33572077 PMCID: PMC7915359 DOI: 10.3390/ijms22041719] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 12/17/2022] Open
Abstract
Adenosine and dopamine interact antagonistically in living mammals. These interactions are mediated via adenosine A2A and dopamine D2 receptors (R). Stimulation of A2AR inhibits and blockade of A2AR enhances D2R-mediated locomotor activation and goal-directed behavior in rodents. In striatal membrane preparations, adenosine decreases both the affinity and the signal transduction of D2R via its interaction with A2AR. Reciprocal A2AR/D2R interactions occur mainly in striatopallidal GABAergic medium spiny neurons (MSNs) of the indirect pathway that are involved in motor control, and in striatal astrocytes. In the nucleus accumbens, they also take place in MSNs involved in reward-related behavior. A2AR and D2R co-aggregate, co-internalize, and co-desensitize. They are at very close distance in biomembranes and form heteromers. Antagonistic interactions between adenosine and dopamine are (at least partially) caused by allosteric receptor–receptor interactions within A2AR/D2R heteromeric complexes. Such interactions may be exploited in novel strategies for the treatment of Parkinson’s disease, schizophrenia, substance abuse, and perhaps also attention deficit-hyperactivity disorder. Little is known about shifting A2AR/D2R heteromer/homodimer equilibria in the brain. Positron emission tomography with suitable ligands may provide in vivo information about receptor crosstalk in the living organism. Some experimental approaches, and strategies for the design of novel imaging agents (e.g., heterobivalent ligands) are proposed in this review.
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Affiliation(s)
- Kavya Prasad
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ Groningen, The Netherlands; (E.F.J.d.V.); (P.H.E.); (R.A.J.O.D.)
- Correspondence: (K.P.); (A.v.W.); Tel.: +31-50-3613215
| | - Erik F. J. de Vries
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ Groningen, The Netherlands; (E.F.J.d.V.); (P.H.E.); (R.A.J.O.D.)
| | - Philip H. Elsinga
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ Groningen, The Netherlands; (E.F.J.d.V.); (P.H.E.); (R.A.J.O.D.)
| | - Rudi A. J. O. Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ Groningen, The Netherlands; (E.F.J.d.V.); (P.H.E.); (R.A.J.O.D.)
- Department of Diagnostic Sciences, Ghent University Faculty of Medicine and Health Sciences, C.Heymanslaan 10, 9000 Gent, Belgium
| | - Aren van Waarde
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ Groningen, The Netherlands; (E.F.J.d.V.); (P.H.E.); (R.A.J.O.D.)
- Correspondence: (K.P.); (A.v.W.); Tel.: +31-50-3613215
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Sun MJ, Liu F, Zhao YF, Wu XA. In Vivo Positron Emission Tomography Imaging of Adenosine A 2A Receptors. Front Pharmacol 2020; 11:599857. [PMID: 33324226 PMCID: PMC7726429 DOI: 10.3389/fphar.2020.599857] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 11/04/2020] [Indexed: 02/05/2023] Open
Abstract
As an invasive nuclear medical imaging technology, positron emission tomography (PET) possess the possibility to imaging the distribution as well as the density of selective receptors via specific PET tracers. Inspired by PET, the development of radio-chemistry has greatly promoted the progress of innovative imaging PET tracers for adenosine receptors, in particular adenosine A2A receptors (A2ARs). PET imaging of A2A receptors play import roles in the research of adenosine related disorders. Several radio-tracers for A2A receptors imaging have been evaluated in human studies. This paper reviews the recent research progress of PET tracers for A2A receptors imaging, and their applications in the diagnosis and treatment of related disease, such as cardiovascular diseases, autoimmune diseases, neurodegenerative and psychiatric disease. The future development of A2A PET tracers were also discussed.
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Affiliation(s)
- Meng-Juan Sun
- Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Acupuncture and Chronobiology Key Laboratory of Sichuan Province, Chengdu, China
| | - Fang Liu
- Department of Laboratory Pathology, Xijing Hospital, Fourth Military Medical University, Xian, China
| | - Ya-Fei Zhao
- Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Acupuncture and Chronobiology Key Laboratory of Sichuan Province, Chengdu, China
| | - Xiao-Ai Wu
- Department of Nuclear Medicine, Laboratory of Clinical Nuclear Medicine, West China Hospital, Sichuan University, Chengdu, China
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11
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Shaw RC, Tamagnan GD, Tavares AAS. Rapidly (and Successfully) Translating Novel Brain Radiotracers From Animal Research Into Clinical Use. Front Neurosci 2020; 14:871. [PMID: 33117115 PMCID: PMC7559529 DOI: 10.3389/fnins.2020.00871] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 07/27/2020] [Indexed: 12/26/2022] Open
Abstract
The advent of preclinical research scanners for in vivo imaging of small animals has added confidence into the multi-step decision-making process of radiotracer discovery and development. Furthermore, it has expanded the utility of imaging techniques available to dissect clinical questions, fostering a cyclic interaction between the clinical and the preclinical worlds. Significant efforts from medicinal chemistry have also made available several high-affinity and selective compounds amenable for radiolabeling, that target different receptors, transporters and enzymes in vivo. This substantially increased the range of applications of molecular imaging using positron emission tomography (PET) or single photon emission computed tomography (SPECT). However, the process of developing novel radiotracers for in vivo imaging of the human brain is a multi-step process that has several inherent pitfalls and technical difficulties, which often hampers the successful translation of novel imaging agents from preclinical research into clinical use. In this paper, the process of radiotracer development and its relevance in brain research is discussed; as well as, its pitfalls, technical challenges and future promises. Examples of successful and unsuccessful translation of brain radiotracers will be presented.
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Affiliation(s)
- Robert C. Shaw
- BHF Centre for Cardiovascular Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Edinburgh Imaging, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Adriana Alexandre S. Tavares
- BHF Centre for Cardiovascular Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Edinburgh Imaging, University of Edinburgh, Edinburgh, United Kingdom
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12
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Schröder S, Lai TH, Toussaint M, Kranz M, Chovsepian A, Shang Q, Dukić-Stefanović S, Deuther-Conrad W, Teodoro R, Wenzel B, Moldovan RP, Pan-Montojo F, Brust P. PET Imaging of the Adenosine A 2A Receptor in the Rotenone-Based Mouse Model of Parkinson's Disease with [ 18F]FESCH Synthesized by a Simplified Two-Step One-Pot Radiolabeling Strategy. Molecules 2020; 25:molecules25071633. [PMID: 32252340 PMCID: PMC7180622 DOI: 10.3390/molecules25071633] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 03/27/2020] [Accepted: 03/27/2020] [Indexed: 12/16/2022] Open
Abstract
The adenosine A2A receptor (A2AR) is regarded as a particularly appropriate target for non-dopaminergic treatment of Parkinson’s disease (PD). An increased A2AR availability has been found in the human striatum at early stages of PD and in patients with PD and dyskinesias. The aim of this small animal positron emission tomography/magnetic resonance (PET/MR) imaging study was to investigate whether rotenone-treated mice reflect the aspect of striatal A2AR upregulation in PD. For that purpose, we selected the known A2AR-specific radiotracer [18F]FESCH and developed a simplified two-step one-pot radiosynthesis. PET images showed a high uptake of [18F]FESCH in the mouse striatum. Concomitantly, metabolism studies with [18F]FESCH revealed the presence of a brain-penetrant radiometabolite. In rotenone-treated mice, a slightly higher striatal A2AR binding of [18F]FESCH was found. Nonetheless, the correlation between the increased A2AR levels within the proposed PD animal model remains to be further investigated.
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Affiliation(s)
- Susann Schröder
- ROTOP Pharmaka Ltd., Department of Research and Development, Dresden 01328, Germany
- Correspondence: ; Tel.: +49-341-234-179-4631
| | - Thu Hang Lai
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Research Site Leipzig, Leipzig 04318, Germany; (T.H.L.); (M.T.); (S.D.-S.); (W.D.-C.); (R.T.); (B.W.); (R.-P.M.); (P.B.)
| | - Magali Toussaint
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Research Site Leipzig, Leipzig 04318, Germany; (T.H.L.); (M.T.); (S.D.-S.); (W.D.-C.); (R.T.); (B.W.); (R.-P.M.); (P.B.)
| | - Mathias Kranz
- PET Imaging Center, University Hospital of North Norway (UNN), Tromsø 9009, Norway;
- Nuclear Medicine and Radiation Biology Research Group, The Arctic University of Norway, Tromsø 9009, Norway
| | - Alexandra Chovsepian
- University Hospital Munich, Department of Psychiatry, Ludwig-Maximilians-Universität (LMU) Munich, Munich 80336, Germany; (A.C.); (F.P.-M.)
| | - Qi Shang
- University Hospital Munich, Department of Neurology, Ludwig-Maximilians-Universität (LMU) Munich, Munich 81377, Germany;
- University Hospital Carl Gustav Carus, Clinic of Neurology, Technische Universität Dresden (TUD), Dresden 01307, Germany
| | - Sladjana Dukić-Stefanović
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Research Site Leipzig, Leipzig 04318, Germany; (T.H.L.); (M.T.); (S.D.-S.); (W.D.-C.); (R.T.); (B.W.); (R.-P.M.); (P.B.)
| | - Winnie Deuther-Conrad
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Research Site Leipzig, Leipzig 04318, Germany; (T.H.L.); (M.T.); (S.D.-S.); (W.D.-C.); (R.T.); (B.W.); (R.-P.M.); (P.B.)
| | - Rodrigo Teodoro
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Research Site Leipzig, Leipzig 04318, Germany; (T.H.L.); (M.T.); (S.D.-S.); (W.D.-C.); (R.T.); (B.W.); (R.-P.M.); (P.B.)
| | - Barbara Wenzel
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Research Site Leipzig, Leipzig 04318, Germany; (T.H.L.); (M.T.); (S.D.-S.); (W.D.-C.); (R.T.); (B.W.); (R.-P.M.); (P.B.)
| | - Rareş-Petru Moldovan
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Research Site Leipzig, Leipzig 04318, Germany; (T.H.L.); (M.T.); (S.D.-S.); (W.D.-C.); (R.T.); (B.W.); (R.-P.M.); (P.B.)
| | - Francisco Pan-Montojo
- University Hospital Munich, Department of Psychiatry, Ludwig-Maximilians-Universität (LMU) Munich, Munich 80336, Germany; (A.C.); (F.P.-M.)
- University Hospital Munich, Department of Neurology, Ludwig-Maximilians-Universität (LMU) Munich, Munich 81377, Germany;
| | - Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Research Site Leipzig, Leipzig 04318, Germany; (T.H.L.); (M.T.); (S.D.-S.); (W.D.-C.); (R.T.); (B.W.); (R.-P.M.); (P.B.)
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13
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McCluskey SP, Plisson C, Rabiner EA, Howes O. Advances in CNS PET: the state-of-the-art for new imaging targets for pathophysiology and drug development. Eur J Nucl Med Mol Imaging 2020; 47:451-489. [PMID: 31541283 PMCID: PMC6974496 DOI: 10.1007/s00259-019-04488-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 08/15/2019] [Indexed: 02/07/2023]
Abstract
PURPOSE A limit on developing new treatments for a number of central nervous system (CNS) disorders has been the inadequate understanding of the in vivo pathophysiology underlying neurological and psychiatric disorders and the lack of in vivo tools to determine brain penetrance, target engagement, and relevant molecular activity of novel drugs. Molecular neuroimaging provides the tools to address this. This article aims to provide a state-of-the-art review of new PET tracers for CNS targets, focusing on developments in the last 5 years for targets recently available for in-human imaging. METHODS We provide an overview of the criteria used to evaluate PET tracers. We then used the National Institute of Mental Health Research Priorities list to identify the key CNS targets. We conducted a PubMed search (search period 1st of January 2013 to 31st of December 2018), which yielded 40 new PET tracers across 16 CNS targets which met our selectivity criteria. For each tracer, we summarised the evidence of its properties and potential for use in studies of CNS pathophysiology and drug evaluation, including its target selectivity and affinity, inter and intra-subject variability, and pharmacokinetic parameters. We also consider its potential limitations and missing characterisation data, but not specific applications in drug development. Where multiple tracers were present for a target, we provide a comparison of their properties. RESULTS AND CONCLUSIONS Our review shows that multiple new tracers have been developed for proteinopathy targets, particularly tau, as well as the purinoceptor P2X7, phosphodiesterase enzyme PDE10A, and synaptic vesicle glycoprotein 2A (SV2A), amongst others. Some of the most promising of these include 18F-MK-6240 for tau imaging, 11C-UCB-J for imaging SV2A, 11C-CURB and 11C-MK-3168 for characterisation of fatty acid amide hydrolase, 18F-FIMX for metabotropic glutamate receptor 1, and 18F-MNI-444 for imaging adenosine 2A. Our review also identifies recurrent issues within the field. Many of the tracers discussed lack in vivo blocking data, reducing confidence in selectivity. Additionally, late-stage identification of substantial off-target sites for multiple tracers highlights incomplete pre-clinical characterisation prior to translation, as well as human disease state studies carried out without confirmation of test-retest reproducibility.
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Affiliation(s)
- Stuart P McCluskey
- Invicro LLC, A Konica Minolta Company, Burlington Danes Building, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK.
- Psychiatric Imaging Group, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital, London, UK.
| | - Christophe Plisson
- Invicro LLC, A Konica Minolta Company, Burlington Danes Building, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK
| | - Eugenii A Rabiner
- Invicro LLC, A Konica Minolta Company, Burlington Danes Building, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK
| | - Oliver Howes
- Psychiatric Imaging Group, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital, London, UK
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14
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Li J, Hong X, Li G, Conti PS, Zhang X, Chen K. PET Imaging of Adenosine Receptors in Diseases. Curr Top Med Chem 2019; 19:1445-1463. [PMID: 31284861 DOI: 10.2174/1568026619666190708163407] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 01/26/2019] [Accepted: 02/02/2019] [Indexed: 01/08/2023]
Abstract
Adenosine receptors (ARs) are a class of purinergic G-protein-coupled receptors (GPCRs). Extracellular adenosine is a pivotal regulation molecule that adjusts physiological function through the interaction with four ARs: A1R, A2AR, A2BR, and A3R. Alterations of ARs function and expression have been studied in neurological diseases (epilepsy, Alzheimer's disease, and Parkinson's disease), cardiovascular diseases, cancer, and inflammation and autoimmune diseases. A series of Positron Emission Tomography (PET) probes for imaging ARs have been developed. The PET imaging probes have provided valuable information for diagnosis and therapy of diseases related to alterations of ARs expression. This review presents a concise overview of various ARs-targeted radioligands for PET imaging in diseases. The most recent advances in PET imaging studies by using ARs-targeted probes are briefly summarized.
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Affiliation(s)
- Jindian Li
- Department of Radiology, Molecular Imaging Center, Keck School of Medicine, University of Southern California, 2250 Alcazar Street, CSC103, Los Angeles, CA 90033, United States.,State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Xingfang Hong
- Laboratory of Pathogen Biology, School of Basic Medical Sciences, Dali University, Dali 671000, China
| | - Guoquan Li
- Department of Radiology, Molecular Imaging Center, Keck School of Medicine, University of Southern California, 2250 Alcazar Street, CSC103, Los Angeles, CA 90033, United States
| | - Peter S Conti
- Department of Radiology, Molecular Imaging Center, Keck School of Medicine, University of Southern California, 2250 Alcazar Street, CSC103, Los Angeles, CA 90033, United States
| | - Xianzhong Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Kai Chen
- Department of Radiology, Molecular Imaging Center, Keck School of Medicine, University of Southern California, 2250 Alcazar Street, CSC103, Los Angeles, CA 90033, United States
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15
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Lee BI, Park MH, Shin SH, Byeon JJ, Park Y, Kim N, Choi J, Shin YG. Quantitative Analysis of Tozadenant Using Liquid Chromatography-Mass Spectrometric Method in Rat Plasma and Its Human Pharmacokinetics Prediction Using Physiologically Based Pharmacokinetic Modeling. Molecules 2019; 24:molecules24071295. [PMID: 30987056 PMCID: PMC6479388 DOI: 10.3390/molecules24071295] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 03/31/2019] [Accepted: 04/01/2019] [Indexed: 12/11/2022] Open
Abstract
Tozadenant is one of the selective adenosine A2a receptor antagonists with a potential to be a new Parkinson's disease (PD) therapeutic drug. In this study, a liquid chromatography-mass spectrometry based bioanalytical method was qualified and applied for the quantitative analysis of tozadenant in rat plasma. A good calibration curve was observed in the range from 1.01 to 2200 ng/mL for tozadenant using a quadratic regression. In vitro and preclinical in vivo pharmacokinetic (PK) properties of tozadenant were studied through the developed bioanalytical methods, and human PK profiles were predicted using physiologically based pharmacokinetic (PBPK) modeling based on these values. The PBPK model was initially optimized using in vitro and in vivo PK data obtained by intravenous administration at a dose of 1 mg/kg in rats. Other in vivo PK data in rats were used to validate the PBPK model. The human PK of tozadenant after oral administration at a dose of 240 mg was simulated by using an optimized and validated PBPK model. The predicted human PK parameters and profiles were similar to the observed clinical data. As a result, optimized PBPK model could reasonably predict the PK in human.
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Affiliation(s)
- Byeong Ill Lee
- College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, Daejeon 34134, Korea.
| | - Min-Ho Park
- College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, Daejeon 34134, Korea.
| | - Seok-Ho Shin
- College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, Daejeon 34134, Korea.
| | - Jin-Ju Byeon
- College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, Daejeon 34134, Korea.
| | - Yuri Park
- College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, Daejeon 34134, Korea.
| | - Nahye Kim
- College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, Daejeon 34134, Korea.
| | - Jangmi Choi
- College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, Daejeon 34134, Korea.
| | - Young G Shin
- College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, Daejeon 34134, Korea.
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16
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In Vivo PET Imaging of Adenosine 2A Receptors in Neuroinflammatory and Neurodegenerative Disease. CONTRAST MEDIA & MOLECULAR IMAGING 2017; 2017:6975841. [PMID: 29348737 PMCID: PMC5733838 DOI: 10.1155/2017/6975841] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 10/18/2017] [Indexed: 01/01/2023]
Abstract
Adenosine receptors are G-protein coupled P1 purinergic receptors that are broadly expressed in the peripheral immune system, vasculature, and the central nervous system (CNS). Within the immune system, adenosine 2A (A2A) receptor-mediated signaling exerts a suppressive effect on ongoing inflammation. In healthy CNS, A2A receptors are expressed mainly within the neurons of the basal ganglia. Alterations in A2A receptor function and expression have been noted in movement disorders, and in Parkinson's disease pharmacological A2A receptor antagonism leads to diminished motor symptoms. Although A2A receptors are expressed only at a low level in the healthy CNS outside striatum, pathological challenge or inflammation has been shown to lead to upregulation of A2A receptors in extrastriatal CNS tissue, and this has been successfully quantitated using in vivo positron emission tomography (PET) imaging and A2A receptor-binding radioligands. Several radioligands for PET imaging of A2A receptors have been developed in recent years, and A2A receptor-targeting PET imaging may thus provide a potential additional tool to evaluate various aspects of neuroinflammation in vivo. This review article provides a brief overview of A2A receptors in healthy brain and in a selection of most important neurological diseases and describes the recent advances in A2A receptor-targeting PET imaging studies.
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17
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Essawy SS, Tawfik MK, Korayem HE. Effects of adenosine receptor antagonists in MPTP mouse model of Parkinson's disease: mitochondrial DNA integrity. Arch Med Sci 2017; 13:659-669. [PMID: 28507584 PMCID: PMC5420638 DOI: 10.5114/aoms.2017.67284] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 05/19/2015] [Indexed: 12/17/2022] Open
Abstract
INTRODUCTION In Parkinson's disease (PD), compelling data indicate a functional link between adenosine/dopamine receptors and the progression of the neurodegenerative process. The present study was carried out to evaluate the effect of the non-selective adenosine receptor (ADR) antagonist caffeine, as well as the selective antagonists 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), an ADRsA1 antagonist, and ((E)-1,3-diethyl-8-(3,4-dimethoxystyryl)-7-methyl-3,7-dihydro-1H-purine-2,6-dione) (KW-6002), an ADRsA2A antagonist, on the prevention of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinsonism in mice. MATERIAL AND METHODS Mice were allocated to five groups: group I - control group; group II: MPTP group, received four injections of MPTP (20 mg/kg, i.p.) at 2 h intervals; groups III, IV, V: received MPTP and i.p. caffeine (20 mg/kg/day) or DPCPX (5 mg/kg/day) or KW-6002 (10 mg/kg/day) starting one week before MPTP injection and continuing for 2 weeks. RESULTS Therapy with caffeine or KW-6002 not only led to the reversibility of movement dysfunction and increased the concentrations of dopamine and ATP levels (p < 0.05), but also, ameliorates the dopaminergic neuron loss and restored the mtDNA and nDNA integrity (p < 0.05). Furthermore, in passive avoidance test, caffeine and DPCPX significantly (p < 0.05) reversed the MPTP-induced memory deficits, whereas the specific ADRsA2A antagonist did not. CONCLUSIONS The current results provide evidence that blockade of both ADRsA1 and ADRsA2A has therapeutic implications in alleviating MPTP-induced motor and cognitive dysfunction and might be a promising candidate for treatment of PD.
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Affiliation(s)
- Soha S. Essawy
- Department of Pharmacology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Mona Kamal Tawfik
- Department of Pharmacology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Horya Erfan Korayem
- Department of Histology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
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18
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Zhou X, Khanapur S, de Jong JR, Willemsen AT, Dierckx RA, Elsinga PH, de Vries EF. In vivo evaluation of [ 11C]preladenant positron emission tomography for quantification of adenosine A 2A receptors in the rat brain. J Cereb Blood Flow Metab 2017; 37:577-589. [PMID: 26917190 PMCID: PMC5381452 DOI: 10.1177/0271678x16634714] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
[11C]Preladenant was developed as a novel adenosine A2A receptor positron emission tomography radioligand. The present study aims to evaluate the suitability of [11C]preladenant positron emission tomography for the quantification of striatal A2A receptor density and the assessment of striatal A2A receptor occupancy by KW-6002. Sixty- or ninety-minute dynamic positron emission tomography imaging was performed on rats. Tracer kinetics was quantified by the two-tissue compartment model, Logan graphical analysis and several reference tissue-based models. Test-retest reproducibility was assessed by repeated imaging on two consecutive days. Two-tissue compartment model and Logan plot estimated comparable distribution volume ( VT) values of ∼10 in the A2A receptor-rich striatum and substantially lower values in all extra-striatal regions (∼1.5-2.5). The simplified reference tissue model with midbrain or occipital cortex as the reference region proved to be the best non-invasive model for quantification of A2A receptor, showing a striatal binding potential ( BPND) value of ∼5.5, and a test-retest variability of ∼5.5%. The brain metabolite analysis showed that at 60-min post injection, 17% of the radioactivity in the brain was due to radioactive metabolites. The ED50 of KW-6002 in rat striatum for i.p. injection was 0.044-0.062 mg/kg. The study demonstrates that [11C]preladenant is a suitable tracer to quantify striatal A2A receptor density and assess A2A receptor occupancy by A2A receptor-targeting molecules.
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Affiliation(s)
- Xiaoyun Zhou
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Shivashankar Khanapur
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Johan R de Jong
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Antoon Tm Willemsen
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Rudi Ajo Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Philip H Elsinga
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Erik Fj de Vries
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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19
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van Waarde A, Dierckx RAJO, Zhou X, Khanapur S, Tsukada H, Ishiwata K, Luurtsema G, de Vries EFJ, Elsinga PH. Potential Therapeutic Applications of Adenosine A 2A Receptor Ligands and Opportunities for A 2A Receptor Imaging. Med Res Rev 2017; 38:5-56. [PMID: 28128443 DOI: 10.1002/med.21432] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 10/31/2016] [Accepted: 11/14/2016] [Indexed: 12/13/2022]
Abstract
Adenosine A2A receptors (A2A Rs) are highly expressed in the human striatum, and at lower densities in the cerebral cortex, the hippocampus, and cells of the immune system. Antagonists of these receptors are potentially useful for the treatment of motor fluctuations, epilepsy, postischemic brain damage, or cognitive impairment, and for the control of an immune checkpoint during immunotherapy of cancer. A2A R agonists may suppress transplant rejection and graft-versus-host disease; be used to treat inflammatory disorders such as asthma, inflammatory bowel disease, and rheumatoid arthritis; be locally applied to promote wound healing and be employed in a strategy for transient opening of the blood-brain barrier (BBB) so that therapeutic drugs and monoclonal antibodies can enter the brain. Increasing A2A R signaling in adipose tissue is also a potential strategy to combat obesity. Several radioligands for positron emission tomography (PET) imaging of A2A Rs have been developed in recent years. This review article presents a critical overview of the potential therapeutic applications of A2A R ligands, the use of A2A R imaging in drug development, and opportunities and limitations of PET imaging in future research.
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Affiliation(s)
- Aren van Waarde
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, 1, 9713 GZ, Groningen, The Netherlands
| | - Rudi A J O Dierckx
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, 1, 9713 GZ, Groningen, The Netherlands.,Department of Nuclear Medicine, University Hospital, Ghent University, De Pintelaan 185, 9000, Ghent, Belgium
| | - Xiaoyun Zhou
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, 1, 9713 GZ, Groningen, The Netherlands
| | - Shivashankar Khanapur
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, 1, 9713 GZ, Groningen, The Netherlands
| | - Hideo Tsukada
- Central Research Laboratory, Hamamatsu Photonics K.K., Hamakita, Hamamatsu, Shizuoka 434-8601, Japan
| | - Kiichi Ishiwata
- Research Institute of Cyclotron and Drug Discovery Research, Southern TOHOKU Research Institute for Neuroscience, 7-115 Yatsuyamada, Koriyama, 963-8052, Japan.,Department of Biofunctional Imaging, Fukushima Medical University, 1 Hikarigaoka, Fukushima, 960-1295, Japan.,Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Gert Luurtsema
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, 1, 9713 GZ, Groningen, The Netherlands
| | - Erik F J de Vries
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, 1, 9713 GZ, Groningen, The Netherlands
| | - Philip H Elsinga
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, 1, 9713 GZ, Groningen, The Netherlands
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20
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Zhou X, Boellaard R, Ishiwata K, Sakata M, Dierckx RAJO, de Jong JR, Nishiyama S, Ohba H, Tsukada H, de Vries EFJ, Elsinga PH. In Vivo Evaluation of 11C-Preladenant for PET Imaging of Adenosine A 2A Receptors in the Conscious Monkey. J Nucl Med 2017; 58:762-767. [PMID: 28062599 DOI: 10.2967/jnumed.116.182410] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 11/10/2016] [Indexed: 12/22/2022] Open
Abstract
11C-preladenant was developed as a novel PET ligand for the adenosine A2A receptors (A2ARs). The present study aimed to evaluate the suitability of 11C-preladenant PET for the quantification of striatal A2ARs and the assessment of A2AR occupancy in the conscious monkey brain. Methods:11C-preladenant was intravenously injected into conscious monkeys (n = 4, 18 PET scans), and a 91-min dynamic scan was started. Arterial blood samples in combination with metabolite analysis were obtained during the scan to provide the input function for kinetic modeling. The distribution volume (VT) was obtained by kinetic modeling with a 2-tissue-compartment model. The simplified reference tissue model (SRTM) with selected reference regions (cerebellum, cingulate, parietal cortex, and occipital cortex) was tested to estimate the binding potential (BPND) in A2AR-rich regions. BPND obtained from the SRTM was compared with distribution volume ratio (DVR)-1. The effects of blood volume, blood delay, and scan duration on BPND and DVR-1 were investigated. VT and BPND were also obtained after preblocking with unlabeled preladenant (1 mg/kg), A2AR-selective KW-6002 (0.5-1 mg/kg), and nonselective adenosine receptor antagonist caffeine (2.5-10 mg/kg). A2AR occupancy was studied with caffeine blockade. Results: Regional uptake of 11C-preladenant was consistent with the distribution of A2ARs in the monkey brain, with the highest uptake in the putamen, followed by the caudate, and the lowest uptake in the cerebellum. Tracer kinetics were well described by the 2-tissue-compartment model with a lower constraint on k4 to stabilize fits. The highest VT was observed in A2AR-rich regions (∼5.8-7.4) and lowest value in the cerebellum (∼1.3). BPND values estimated from the SRTM with different scan durations were comparable and were in agreement with DVR-1 (∼4.3-5.3 in A2AR-rich regions). Preladenant preinjection decreased the tracer uptake in A2AR-rich regions to the level of the reference regions. Caffeine pretreatment reduced the tracer uptake in the striatum in a dose-dependent manner. Conclusion:11C-preladenant PET is suitable for noninvasive quantification of A2ARs and assessment of A2AR occupancy in A2AR-rich regions in the monkey brain. SRTM using the cerebellum as the reference tissue is the applicable model for A2AR quantification.
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Affiliation(s)
- Xiaoyun Zhou
- University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Ronald Boellaard
- University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Kiichi Ishiwata
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.,Institute of Cyclotron and Drug Discovery Research, Southern TOHOKU Research Institute for Neuroscience, Koriyama, Japan.,Department of Biofunctional Imaging, Fukushima Medical University, Fukushima, Japan; and
| | - Muneyuki Sakata
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Rudi A J O Dierckx
- University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Johan R de Jong
- University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Shingo Nishiyama
- Central Research Laboratory, Hamamatsu Photonics K.K., Hamamatsu, Japan
| | - Hiroyuki Ohba
- Central Research Laboratory, Hamamatsu Photonics K.K., Hamamatsu, Japan
| | - Hideo Tsukada
- Central Research Laboratory, Hamamatsu Photonics K.K., Hamamatsu, Japan
| | - Erik F J de Vries
- University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Philip H Elsinga
- University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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21
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Khanapur S, van Waarde A, Dierckx RAJO, Elsinga PH, Koole MJB. Preclinical Evaluation and Quantification of 18F-Fluoroethyl and 18F-Fluoropropyl Analogs of SCH442416 as Radioligands for PET Imaging of the Adenosine A 2A Receptor in Rat Brain. J Nucl Med 2016; 58:466-472. [PMID: 27789720 DOI: 10.2967/jnumed.116.178103] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 10/02/2016] [Indexed: 11/16/2022] Open
Abstract
The cerebral adenosine A2A receptor is an attractive therapeutic target for neuropsychiatric disorders. 18F-fluoroethyl and 18F-fluoropropyl analogs of 18F-labeled pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine (SCH442416) (18F-FESCH and 18F-FPSCH, respectively) were developed as A2A receptor-specific PET ligands. Our aim was to determine an appropriate compartmental model for tracer kinetics, evaluate a reference tissue approach, and select the most suitable PET ligand. Methods: A 90-min dynamic PET scan with arterial blood sampling and metabolite analysis was acquired for 22 healthy male Wistar rats starting at the time of 18F-FESCH (n = 12) and 18F-FPSCH (n = 10) injection. For each tracer, half the animals were vehicle-treated whereas the other half were pretreated with the A2A receptor-selective antagonist KW-6002, inducing full blocking. Regional tissue total volume of distribution (VT) was estimated by 1- and 2-tissue-compartment modeling (1TCM and 2TCM, respectively) and Logan graphical analysis. Midbrain, cerebellum, and hippocampus were evaluated as the reference region by comparing baseline VT with VT under full blocking conditions and comparing striatal nondisplaceable binding potential (BPND) using a simplified reference tissue model (SRTM) with distribution volume ratio minus 1 (DVR - 1) for 60- and 90-min scans. Results: On the basis of the Akaike information criterion, 1TCM and 2TCM were the most appropriate models for 18F-FPSCH (baseline striatal VT, 3.7 ± 1.1) and 18F-FESCH (baseline striatal VT, 5.0 ± 2.0), respectively. Baseline striatal VT did not significantly differ between tracers. After pretreatment, striatal VT was reduced significantly, with no significant decrease in hippocampus, midbrain, or cerebellum VT Baseline striatal SRTM BPND did not differ significantly from DVR - 1 except for 18F-FPSCH when using a 60-min scan and midbrain as the reference region, whereas Bland-Altman analysis found a smaller bias for 18F-FESCH and a 60-min scan. After pretreatment, striatal SRTM BPND did not significantly differ from zero except for 18F-FPSCH when using hippocampus as the reference region. Striatal SRTM BPND using midbrain or cerebellum as the reference region was significantly lower for 18F-FPSCH (range, 1.41-2.62) than for 18F-FESCH (range, 1.64-3.36). Conclusion: Dynamic PET imaging under baseline and blocking conditions determined 18F-FESCH to be the most suitable PET ligand for quantifying A2A receptor expression in the rat brain. Accurate quantification is achieved by a 60-min dynamic PET scan and the use of either cerebellum or midbrain as the reference region.
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Affiliation(s)
- Shivashankar Khanapur
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; and
| | - Aren van Waarde
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; and
| | - Rudi A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; and
| | - Philip H Elsinga
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; and
| | - Michel J B Koole
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; and .,Department of Nuclear Medicine and Molecular Imaging, KU Leuven, Leuven, Belgium
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22
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Vala C, Morley TJ, Zhang X, Papin C, Tavares AAS, Lee HS, Constantinescu C, Barret O, Carroll VM, Baldwin RM, Tamagnan GD, Alagille D. Synthesis and in vivo Evaluation of Fluorine-18 and Iodine-123 Pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine Derivatives as PET and SPECT Radiotracers for Mapping A2A Receptors. ChemMedChem 2016; 11:1936-43. [PMID: 27407017 DOI: 10.1002/cmdc.201600219] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 06/15/2016] [Indexed: 11/06/2022]
Abstract
Imaging agents that target adenosine type 2A (A2A ) receptors play an important role in evaluating new pharmaceuticals targeting these receptors, such as those currently being developed for the treatment of movement disorders like Parkinson's disease. They are also useful for monitoring progression and treatment efficacy by providing a noninvasive tool to map changes in A2A receptor density and function in neurodegenerative diseases. We previously described the successful evaluation of two A2A -specific radiotracers in both nonhuman primates and in subsequent human clinical trials: [(123) I]MNI-420 and [(18) F]MNI-444. Herein we describe the development of both of these radiotracers by selection from a series of A2A ligands, based on the pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine core of preladenant. Each of this series of 16 ligands was found to bind to recombinant human A2A receptor in the low nanomolar range, and of these 16, six were radiolabeled with either fluorine-18 or iodine-123 and evaluated in nonhuman primates. These initial in vivo results resulted in the identification of 7-(2-(4-(4-(2-[(18) F]fluoroethoxy)phenyl)piperazin-1-yl)ethyl)-2-(furan-2-yl)-7H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-amine ([(18) F]MNI-444) and 7-(2-(4-(2-fluoro-4-[(123) I]iodophenyl)piperazin-1-yl)ethyl)-2-(furan-2-yl)-7H-imidazo[1,2-c]pyrazolo[4,3-e]pyrimidin-5-amine ([(123) I]MNI-420) as PET and SPECT radiopharmaceuticals for mapping A2A receptors in brain.
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Affiliation(s)
- Christine Vala
- Molecular NeuroImaging, a division of inviCRO, 60 Temple Street, Suite 8B, New Haven, CT, 06510, USA
| | - Thomas J Morley
- Molecular NeuroImaging, a division of inviCRO, 60 Temple Street, Suite 8B, New Haven, CT, 06510, USA.
| | - Xuechun Zhang
- Molecular NeuroImaging, a division of inviCRO, 60 Temple Street, Suite 8B, New Haven, CT, 06510, USA
| | - Caroline Papin
- Molecular NeuroImaging, a division of inviCRO, 60 Temple Street, Suite 8B, New Haven, CT, 06510, USA
| | | | - H Sharon Lee
- Molecular NeuroImaging, a division of inviCRO, 60 Temple Street, Suite 8B, New Haven, CT, 06510, USA
| | - Cristian Constantinescu
- Molecular NeuroImaging, a division of inviCRO, 60 Temple Street, Suite 8B, New Haven, CT, 06510, USA
| | - Olivier Barret
- Molecular NeuroImaging, a division of inviCRO, 60 Temple Street, Suite 8B, New Haven, CT, 06510, USA
| | - Vincent M Carroll
- Molecular NeuroImaging, a division of inviCRO, 60 Temple Street, Suite 8B, New Haven, CT, 06510, USA
| | - Ronald M Baldwin
- Molecular NeuroImaging, a division of inviCRO, 60 Temple Street, Suite 8B, New Haven, CT, 06510, USA
| | - Gilles D Tamagnan
- Molecular NeuroImaging, a division of inviCRO, 60 Temple Street, Suite 8B, New Haven, CT, 06510, USA
| | - David Alagille
- Molecular NeuroImaging, a division of inviCRO, 60 Temple Street, Suite 8B, New Haven, CT, 06510, USA
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Abstract
INTRODUCTION Parkinson's disease (PD) is one of the most challenging neurodegenerative disorders to treat as it manifests with a large variety of troublesome, and often disabling, motor and non-motor symptoms. Despite limitations, such as motor and other complications, levodopa remains the most effective drug in the treatment of PD. AREAS COVERED In this review, we focus on phase 2 and 3 studies describing new and emerging medical therapies in PD. We discuss new formulations of levodopa, medications that prolong levodopa response and ameliorate levodopa-induced dyskinesias, and innovative delivery methods that are currently being evaluated in clinical trials or are in development with the promise of better efficacy and tolerability. We also describe novel non-dopaminergic drugs that have been identified for treatment of motor and non-motor symptoms. A specific section is designated for potential disease modifying therapies. EXPERT OPINION Alternative formulations of levodopa appear to be promising especially to help with the motor fluctuations either by providing sustained benefits with controlled released formulations or ameliorate sudden OFF by formulations such as inhaled levodopa. Several different medications affecting non-dopaminergic pathways are being evaluated which may aide levodopa. As the understanding of the disease grows further, numerous novel neuroprotective or disease modifying therapies have been suggested. This along with development of medications to treat various non-motor symptoms will help improve quality of life of patients with PD.
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Affiliation(s)
- Mitesh Lotia
- a Parkinson's Disease Center and Movement Disorders Clinic, Department of Neurology , Baylor College of Medicine , Houston , TX , USA
| | - Joseph Jankovic
- a Parkinson's Disease Center and Movement Disorders Clinic, Department of Neurology , Baylor College of Medicine , Houston , TX , USA
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24
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Janssen B, Vugts DJ, Funke U, Molenaar GT, Kruijer PS, van Berckel BNM, Lammertsma AA, Windhorst AD. Imaging of neuroinflammation in Alzheimer's disease, multiple sclerosis and stroke: Recent developments in positron emission tomography. Biochim Biophys Acta Mol Basis Dis 2015; 1862:425-41. [PMID: 26643549 DOI: 10.1016/j.bbadis.2015.11.011] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 10/09/2015] [Accepted: 11/19/2015] [Indexed: 12/13/2022]
Abstract
Neuroinflammation is thought to play a pivotal role in many diseases affecting the brain, including Alzheimer's disease, multiple sclerosis and stroke. Neuroinflammation is characterised predominantly by microglial activation, which can be visualised using positron emission tomography (PET). Traditionally, translocator protein 18kDa (TSPO) is the target for imaging of neuroinflammation using PET. In this review, recent preclinical and clinical research using PET in Alzheimer's disease, multiple sclerosis and stroke is summarised. In addition, new molecular targets for imaging of neuroinflammation, such as monoamine oxidases, adenosine receptors and cannabinoid receptor type 2, are discussed. This article is part of a Special Issue entitled: Neuro Inflammation edited by Helga E. de Vries and Markus Schwaninger.
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Affiliation(s)
- Bieneke Janssen
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands.
| | - Danielle J Vugts
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Uta Funke
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands; BV Cyclotron VU, Amsterdam, The Netherlands
| | - Ger T Molenaar
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands; BV Cyclotron VU, Amsterdam, The Netherlands
| | | | - Bart N M van Berckel
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Adriaan A Lammertsma
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Albert D Windhorst
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands.
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25
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Pourcher E, Huot P. Adenosine 2A Receptor Antagonists for the Treatment of Motor Symptoms in Parkinson's Disease. Mov Disord Clin Pract 2015; 2:331-340. [PMID: 30363540 DOI: 10.1002/mdc3.12187] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 03/20/2015] [Accepted: 03/25/2015] [Indexed: 12/20/2022] Open
Abstract
Background Treatment of motor fluctuations in Parkinson's disease (PD) remains an unmet challenge. Adenosine 2A (A2A) receptors are located along the indirect pathway and represent a potential target to enhance l-3,4-dihydroxyphenylalanine (l-DOPA) antiparkinsonian action. Methods This article summarizes the preclinical and clinical literature on A2A antagonists in PD, with a specific focus on their effect on off time, on time, and dyskinesia. Findings Several A2A receptor antagonists have been tested in preclinical studies and clinical trials. In preclinical studies, A2A antagonists enhanced l-DOPA antiparkinsonian action without exacerbating dyskinesia, but A2A antagonists were generally administered in combination with a subthreshold dose of l-DOPA, which is different to the paradigms used in clinical trials, where A2A antagonists were usually added to an optimal antiparkinsonian regimen. In clinical settings, A2A antagonists generally reduced duration of off time, by as much as 25% in some studies. The effect of on time duration is less clear, and in a few studies an exacerbation of dyskinesia was reported. Two A2A antagonists have been tested in phase III settings: istradefylline and preladenant. Istradefylline was effective in two phase III trials, but ineffective in another; the drug has been commercially available in Japan since 2013. In contrast, preladenant was ineffective in a phase III trial and the drug was discontinued. A phase III study with tozadenant will begin in 2015; the drug was effective at reducing off time in a phase IIb study. Other A2A antagonists are in development at the preclinical and early clinical levels.
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Affiliation(s)
- Emmanuelle Pourcher
- Clinique Sainte-Anne Mémoire et Mouvement Faculty of Medicine Laval University Quebec City Quebec Canada.,Centre Thématique de Recherche en Neuroscience Laval University Quebec City Quebec Canada
| | - Philippe Huot
- Department of Pharmacology Faculty of Medicine University of Montreal Montreal Quebec Canada.,Division of Neurology Centre Hospitalier de l'Université de Montréal Montreal Quebec Canada
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26
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Preti D, Baraldi PG, Moorman AR, Borea PA, Varani K. History and perspectives of A2A adenosine receptor antagonists as potential therapeutic agents. Med Res Rev 2015; 35:790-848. [PMID: 25821194 DOI: 10.1002/med.21344] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Growing evidence emphasizes that the purine nucleoside adenosine plays an active role as a local regulator in different pathologies. Adenosine is a ubiquitous nucleoside involved in various physiological and pathological functions by stimulating A1 , A2A , A2B , and A3 adenosine receptors (ARs). At the present time, the role of A2A ARs is well known in physiological conditions and in a variety of pathologies, including inflammatory tissue damage and neurodegenerative disorders. In particular, the use of selective A2A antagonists has been reported to be potentially useful in the treatment of Parkinson's disease (PD). In this review, A2A AR signal transduction pathways, together with an analysis of the structure-activity relationships of A2A antagonists, and their corresponding pharmacological roles and therapeutic potential have been presented. The initial results from an emerging polypharmacological approach are also analyzed. This approach is based on the optimization of the affinity and/or functional activity of the examined compounds toward multiple targets, such as A1 /A2A ARs and monoamine oxidase-B (MAO-B), both closely implicated in the pathogenesis of PD.
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Affiliation(s)
- Delia Preti
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, 44121, Ferrara, Italy
| | - Pier Giovanni Baraldi
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, 44121, Ferrara, Italy
| | | | - Pier Andrea Borea
- Section of Pharmacology, Department of Medical Science, University of Ferrara, 44121, Ferrara, Italy
| | - Katia Varani
- Section of Pharmacology, Department of Medical Science, University of Ferrara, 44121, Ferrara, Italy
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27
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Barret O, Hannestad J, Vala C, Alagille D, Tavares A, Laruelle M, Jennings D, Marek K, Russell D, Seibyl J, Tamagnan G. Characterization in humans of 18F-MNI-444, a PET radiotracer for brain adenosine 2A receptors. J Nucl Med 2015; 56:586-91. [PMID: 25698783 DOI: 10.2967/jnumed.114.152546] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 01/26/2015] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED PET with selective adenosine 2A receptor (A2A) radiotracers can be used to study a variety of neurodegenerative and neuropsychiatric disorders in vivo and to support drug-discovery studies targeting A2A. The aim of this study was to describe the first in vivo evaluation of (18)F-MNI-444, a novel PET radiotracer for imaging A2A, in healthy human subjects. METHODS Ten healthy human volunteers were enrolled in this study; 6 completed the brain PET studies and 4 participated in the whole-body PET studies. Arterial blood was collected for invasive kinetic modeling of the brain PET data. Noninvasive methods of data quantification were also explored. Test-retest reproducibility was evaluated in 5 subjects. Radiotracer distribution and dosimetry was determined using serial whole-body PET images acquired over 6 h post-radiotracer injection. Urine samples were collected to calculate urinary excretion. RESULTS After intravenous bolus injection, (18)F-MNI-444 rapidly entered the brain and displayed a distribution consistent with known A2A densities in the brain. Binding potentials ranging from 2.6 to 4.9 were measured in A2A-rich regions, with an average test-retest variability of less than 10%. The estimated whole-body radiation effective dose was approximately 0.023 mSv/MBq. CONCLUSION (18)F-MNI-444 is a useful PET radiotracer for imaging A2A in the human brain. The superior in vivo brain kinetic properties of (18)F-MNI-444, compared with previously developed A2A radiotracers, provide the opportunity to foster global use of in vivo A2A PET imaging in neuroscience research.
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Affiliation(s)
- Olivier Barret
- Molecular NeuroImaging, LLC, New Haven, Connecticut; and
| | | | - Christine Vala
- Molecular NeuroImaging, LLC, New Haven, Connecticut; and
| | - David Alagille
- Molecular NeuroImaging, LLC, New Haven, Connecticut; and
| | | | | | - Danna Jennings
- Molecular NeuroImaging, LLC, New Haven, Connecticut; and
| | - Ken Marek
- Molecular NeuroImaging, LLC, New Haven, Connecticut; and
| | - David Russell
- Molecular NeuroImaging, LLC, New Haven, Connecticut; and
| | - John Seibyl
- Molecular NeuroImaging, LLC, New Haven, Connecticut; and
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