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van der Aart J, Golla SSV, van der Pluijm M, Schwarte LA, Schuit RC, Klein PJ, Metaxas A, Windhorst AD, Boellaard R, Lammertsma AA, van Berckel BNM. First in human evaluation of [ 18F]PK-209, a PET ligand for the ion channel binding site of NMDA receptors. EJNMMI Res 2018; 8:69. [PMID: 30054846 PMCID: PMC6063804 DOI: 10.1186/s13550-018-0424-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 07/06/2018] [Indexed: 12/05/2022] Open
Abstract
Background Efforts to develop suitable positron emission tomography (PET) tracers for the ion channel site of human N-methyl-d-aspartate (NMDA) receptors have had limited success. [18F]PK-209 is a GMOM derivative that binds to the intrachannel phencyclidine site with high affinity and selectivity. Primate PET studies have shown that the volume of distribution in the brain was reduced by administration of the NMDA receptor antagonist MK-801, consistent with substantial specific binding. The purpose of the present study was to evaluate [18F]PK-209 in 10 healthy humans by assessing test–retest reproducibility and binding specificity following intravenous S-ketamine administration (0.5 mg ∙ kg−1). Five healthy subjects underwent a test–retest protocol, and five others a baseline-ketamine protocol. In all cases dynamic, 120-min PET scans were acquired together with metabolite-corrected arterial plasma input functions. Additional input functions were tested based on within-subject and population-average parent fractions. Results Best fits of the brain time-activity curves were obtained using an irreversible two-tissue compartment model with additional blood volume parameter. Mean test–retest variability of the net rate of influx Ki varied between 7 and 24% depending on the input function. There were no consistent changes in [18F]PK-209 PET parameters following ketamine administration, which may be a consequence of the complex endogenous ligand processes that affect channel gating. Conclusions The molecular interaction between [18F]PK-209 and the binding site within the NMDA receptor ion channel is insufficiently reproducible and specific to be a reliable imaging agent for its quantification. Trial registration EudraCT 2014-001735-36. Registered 28 April 2014
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Affiliation(s)
- Jasper van der Aart
- Department of Radiology & Nuclear Medicine, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands. .,Centre for Human Drug Research, Leiden, The Netherlands.
| | - Sandeep S V Golla
- Department of Radiology & Nuclear Medicine, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Marieke van der Pluijm
- Department of Radiology & Nuclear Medicine, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Lothar A Schwarte
- Department of Radiology & Nuclear Medicine, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Robert C Schuit
- Department of Radiology & Nuclear Medicine, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Pieter J Klein
- Department of Radiology & Nuclear Medicine, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Athanasios Metaxas
- Department of Radiology & Nuclear Medicine, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Albert D Windhorst
- Department of Radiology & Nuclear Medicine, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Ronald Boellaard
- Department of Radiology & Nuclear Medicine, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Adriaan A Lammertsma
- Department of Radiology & Nuclear Medicine, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Bart N M van Berckel
- Department of Radiology & Nuclear Medicine, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
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