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Liu C, Tang J, Xu Y, Cao S, Fang Y, Zhao C, Chen Z. Molar activity of [ 18F]FP-(+)-DTBZ radiopharmaceutical: Determination and its effect on quantitative analysis of VMAT2 autoradiography. J Pharm Biomed Anal 2021; 203:114212. [PMID: 34153939 DOI: 10.1016/j.jpba.2021.114212] [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: 06/19/2020] [Revised: 04/24/2021] [Accepted: 06/13/2021] [Indexed: 10/21/2022]
Abstract
[18F]fluoropropyl-(+)-dihydrotetrabenazine ([18F]FP-(+)-DTBZ) is a rising positron tracer for imaging vesicular monoamine transporter II (VMAT2) in the central nervous system. The present work was to develop a novel chromatographic method capable of the molar activity (Am) determination of [18F]FP-(+)-DTBZ. As a complement work of the Am measurement, we also investigated the effect of Am on the quantitative analysis of VMAT2 autoradiography with [18F]FP-(+)-DTBZ. The Am determination was performed by high performance liquid chromatography (HPLC) using the non-radioactive standard (FP-(+)-DTBZ) for calibration plot of peak area against concentration. Based on this correlation, the Am of [18F]FP-(+)-DTBZ was calculated and corrected to the end of synthesis. In the quantitative analysis of in vitro VMAT2 autoradiography, the striatum radioactivity uptake together with the uptake ratio of striatum versus cortex reduced along with the decrease of Am and the increase of the FP-(+)-DTBZ content. Therefore, the Am and the corresponding FP-(+)-DTBZ content have a significant effect on the quantitative analysis of VMAT2 autoradiography using [18F]FP-(+)-DTBZ.
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Affiliation(s)
- Chunyi Liu
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, 214063, China
| | - Jie Tang
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, 214063, China
| | - Yingjiao Xu
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, 214063, China; Department of Radiopharmaceuticals, School of Pharmacy, Nanjing Medical University, Nanjing, 211166, China
| | - Shanshan Cao
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, 214063, China
| | - Yi Fang
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, 214063, China
| | - Chao Zhao
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, 214063, China
| | - Zhengping Chen
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, 214063, China.
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Zhao C, Liu C, Tang J, Xu Y, Xie M, Chen Z. An Efficient Automated Radiosynthesis and Bioactivity Confirmation of VMAT2 Tracer [ 18F]FP-(+)-DTBZ. Mol Imaging Biol 2021; 22:265-273. [PMID: 31165386 DOI: 10.1007/s11307-019-01379-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
PURPOSE The aim of this study was to optimize the radiolabeling method of [18F]fluoropropyl-(+)-dihydrotetrabenazine ([18F]FP-(+)-DTBZ) to fulfill the demand of preclinical and clinical application. PROCEDURES Optimized labeling conditions were performed by altering the molar ratio of precursor to base (P/B), base species, solvents, reaction temperature, reaction time, and precursor concentration through manual radiosynthesis of [18F]FP-(+)-DTBZ. The conditions with the highest radiochemical yield (RCY) were applied to automated radiosynthesis, and the crude product was purified with a Sep-Pak Plus C18 cartridge. Quality control and stability of [18F]FP-(+)-DTBZ were carried out by HPLC. In vitro cellular uptake and blocking assays were conducted in human neuroblastoma cell line SH-SY5Y. In vivo imaging with small animal positron emission tomography (microPET) was performed with Sprague-Dawley rats. RESULTS Under the optimized conditions (P/K2CO3 = 1:8, heating at 120 °C for 3 min in dimethyl sulfoxide), an RCY of 88.7 % was obtained with 1.0 mg precursor. The optimized reaction conditions were successfully applied to an automated module and gave a high activity yield (AY) of 30-55 % in about 40 min with a > 99.0 % radiochemical purity (RCP) and a > 44.4 GBq/μmol molar activity (Am). Stability test displayed that the RCP retained > 98.0 % in 8 h in saline and in phosphate buffer saline (PBS, pH 7.4). In vitro cellular uptake assay showed accumulation of [18F]FP-(+)-DTBZ in SH-SY5Y cells, which could be significantly inhibited by vesicular monoamine transporter 2 (VMAT2) inhibitor DTBZ. MicroPET images of rat brain displayed that the striatum showed the highest uptake with a standardized uptake value (SUV) of 3.91 ± 0.30 at ~ 70 min. Co-injection with DTBZ (1.0 mg/kg) resulted in a 75 % decrease of the striatal SUV, confirming the specificity of [18F]FP-(+)-DTBZ to VMAT2. CONCLUSIONS We obtained an optimized radiolabeling method of [18F]FP-(+)-DTBZ and successfully applied it to a commercial available module. The automated synthesis gave a high AY and RCP of [18F]FP-(+)-DTBZ with high and specific binding to VMAT2, facilitating its routine application for VMAT2 tracing.
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Affiliation(s)
- Chao Zhao
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, 221004, China
| | - Chunyi Liu
- Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, 214063, China
| | - Jie Tang
- Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, 214063, China
| | - Yingjiao Xu
- Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, 214063, China
| | - Minhao Xie
- Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, 214063, China
| | - Zhengping Chen
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, 221004, China. .,Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, 214063, China.
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Abstract
Positron emission tomography (PET) is a non-invasive imaging technology employed to describe metabolic, physiological, and biochemical processes in vivo. These include receptor availability, metabolic changes, neurotransmitter release, and alterations of gene expression in the brain. Since the introduction of dedicated small-animal PET systems along with the development of many novel PET imaging probes, the number of PET studies using rats and mice in basic biomedical research tremendously increased over the last decade. This article reviews challenges and advances of quantitative rodent brain imaging to make the readers aware of its physical limitations, as well as to inspire them for its potential applications in preclinical research. In the first section, we briefly discuss the limitations of small-animal PET systems in terms of spatial resolution and sensitivity and point to possible improvements in detector development. In addition, different acquisition and post-processing methods used in rodent PET studies are summarized. We further discuss factors influencing the test-retest variability in small-animal PET studies, e.g., different receptor quantification methodologies which have been mainly translated from human to rodent receptor studies to determine the binding potential and changes of receptor availability and radioligand affinity. We further review different kinetic modeling approaches to obtain quantitative binding data in rodents and PET studies focusing on the quantification of endogenous neurotransmitter release using pharmacological interventions. While several studies have focused on the dopamine system due to the availability of several PET tracers which are sensitive to dopamine release, other neurotransmitter systems have become more and more into focus and are described in this review, as well. We further provide an overview of latest genome engineering technologies, including the CRISPR/Cas9 and DREADD systems that may advance our understanding of brain disorders and function and how imaging has been successfully applied to animal models of human brain disorders. Finally, we review the strengths and opportunities of simultaneous PET/magnetic resonance imaging systems to study drug-receptor interactions and challenges for the translation of PET results from bench to bedside.
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Cong GZ, Ghosh KK, Mishra S, Gulyás M, Kovács T, Máthé D, Padmanabhan P, Gulyás B. Targeted pancreatic beta cell imaging for early diagnosis. Eur J Cell Biol 2020; 99:151110. [PMID: 33070042 DOI: 10.1016/j.ejcb.2020.151110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 06/29/2020] [Accepted: 07/22/2020] [Indexed: 12/12/2022] Open
Abstract
Pancreatic beta cells are important in blood glucose level regulation. As type 1 and 2 diabetes are getting prevalent worldwide, we need to explore new methods for early detection of beta cell-related afflictions. Using bioimaging techniques to measure beta cell mass is crucial because a decrease in beta cell density is seen in diseases such as diabetes and thus can be a new way of diagnosis for such diseases. We also need to appraise beta cell purity in transplanted islets for type 1 diabetes patients. Sufficient amount of functional beta cells must also be determined before being transplanted to the patients. In this review, indirect imaging of beta cells will be discussed. This includes membrane protein on pancreatic beta cells whereby specific probes are designed for different imaging modalities mainly magnetic resonance imaging, positron emission tomography and fluorescence imaging. Direct imaging of insulin is also explored though probes synthesized for such function are relatively fewer. The path for successful pancreatic beta cell imaging is fraught with challenges like non-specific binding, lack of beta cell-restricted targets, the requirement of probes to cross multiple lipid layers to bind to intracellular insulin. Hence, there is an urgent need to develop new imaging techniques and innovative probing constructs in the entire imaging chain of bioengineering to provide early detection of beta cell-related pathology.
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Affiliation(s)
- Goh Zheng Cong
- Lee Kong Chian School of Medicine, Nanyang Technological University, 59 Nanyang Drive, Singapore 636921, Singapore
| | - Krishna Kanta Ghosh
- Lee Kong Chian School of Medicine, Nanyang Technological University, 59 Nanyang Drive, Singapore 636921, Singapore
| | - Sachin Mishra
- Lee Kong Chian School of Medicine, Nanyang Technological University, 59 Nanyang Drive, Singapore 636921, Singapore
| | - Miklós Gulyás
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Dag Hammarskölds väg 20, Uppsala Se-751 85, Sweden
| | - Tibor Kovács
- Institute of Radiochemistry and Radioecology, University of Pannonia, Egyetem u. 10, H-8200 Veszprém, Hungary
| | - Domokos Máthé
- Department of Biophysics and Radiation Biology, Semmelweis University Faculty of Medicine, Tűzoltó u. 37-47, Budapest H-1094, Hungary
| | - Parasuraman Padmanabhan
- Lee Kong Chian School of Medicine, Nanyang Technological University, 59 Nanyang Drive, Singapore 636921, Singapore.
| | - Balázs Gulyás
- Lee Kong Chian School of Medicine, Nanyang Technological University, 59 Nanyang Drive, Singapore 636921, Singapore.
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Jiang D, Lu X, Li Z, Rydberg N, Zuo C, Peng F, Hua F, Guan Y, Xie F. Increased Vesicular Monoamine Transporter 2 (VMAT2) and Dopamine Transporter (DAT) Expression in Adolescent Brain Development: A Longitudinal Micro-PET/CT Study in Rodent. Front Neurosci 2019; 12:1052. [PMID: 30697146 PMCID: PMC6340981 DOI: 10.3389/fnins.2018.01052] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 12/27/2018] [Indexed: 12/28/2022] Open
Abstract
Background: Brain development and maturation in adolescence is a complex process with active changes of metabolic and neurotransmission pathways. Positron emission tomography (PET) is a useful imaging modality for tracking metabolic and functional changes in adolescent brain. In this study, changes of glucose metabolism, expression of vesicular monoamine transporter 2 and dopamine transporter during adolescent brain development in rats were investigated with PET/CT. Methods: A longitudinal PET/CT study of age-dependent changes of VMAT2, DAT and glucose metabolism in adolescent brain was conducted in a group of Wistar rats (n = 6) post sequential intravenous injection of 18F-PF-(+)-DTBZ, 11C-CFT, and 18F-FDG, respectively. PET acquisition was performed at 2, 4, 9, and 12 months of age. Radiotracer uptake in different brain regions, including the striatum, cerebellum, and hippocampus, were quantified and recorded as Standardized uptake value (SUV) and striatal specific uptake ratio (SUVR: SUV in brain regions/SUV in cerebellum). Results: Variable uptake of 18F-PF-(+)-DTBZ and 11C-CFT were detected, with highest level uptake in the striatum and accumbens. There was significant age-dependent increase of 18F-PF-(+)-DTBZ and 11C-CFT uptake in the striatum from 2 months of age (SUV: 1.36 ± 0.22, 1.37 ± 0.39, respectively), to 4 months (SUV: 2.22 ± 0.29, 2.04 ± 0.33), 9 months (1.98 ± 0.34, 2.09 ± 0.18), 12 months (SUV: 1.93 ± 0.19, 2.00 ± 0.17) of age, SUV of 18F-FDG also increased from 2 months of age to older ages (SUV in the striatum: 3.71 ± 0.78 at 2 month, 5.28 ± 0.81, 5.14 ± 0.73, 4.94 ± 0.50 at 4, 9, 12 month, respectively). Conclusion: Age-dependent increases of striatal of 18F-FDG, 18F-PF-(+)-DTBZ, and 11C-CFT uptake were detected in rats from 2 to 4 month of age, demonstrating striatal development presents over the first 4 months of age. Four months of age can be considered a safe threshold to launch brain disease studies for exclusion of confusion of continuing tissue development. These findings support further investigation of age-dependent changes in expression of DAT, VMAT2, and glucose metabolism for their potential use as a new imaging biomarker for study of brain development and functional maturation.
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Affiliation(s)
- Donglang Jiang
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Xiuhong Lu
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Zijing Li
- Center for Molecular Imaging and Translational Medicine, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Nicklas Rydberg
- Department of Radiology, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Chuantao Zuo
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Fangyu Peng
- Department of Radiology, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Fengchun Hua
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Yihui Guan
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Fang Xie
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
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Evaluation of drug effects on cerebral blood flow and glucose uptake in un-anesthetized and un-stimulated rats: application of free-moving apparatus enabling to keep rats free during PET/SPECT tracer injection and uptake. Nucl Med Commun 2018; 39:753-760. [PMID: 29771718 PMCID: PMC6075887 DOI: 10.1097/mnm.0000000000000863] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Objectives The purpose of this study is the development of novel fluorine-18-fluorodeoxyglucose (18F-FDG)-PET and 99mTc-hexamethylpropylene amine oxime (HMPAO) SPECT methods with free-moving apparatus on conscious rats to investigate brain activity without the effects of anesthesia and tactual stimulation. We also assessed the sensitivity of the experimental system by an intervention study using fluoxetine as a reference drug. Materials and methods A catheter was inserted into the femoral vein and connected to a free-moving cannula system. After fluoxetine administration, the rats were given an injection of 18F-FDG or 99mTc-HMPAO via the intravenous cannula and released into a free-moving cage. After the tracer was trapped in the brain, the rats were anesthetized and scanned with PET or SPECT scanners. Then a volume of interest analysis and statistical parametric mapping were performed. Results We could inject the tracer without touching the rats, while keeping them conscious until the tracers were distributed and trapped in the brain using the developed system. The effects of fluoxetine on glucose uptake and cerebral blood flow were perceptively detected by volume of interest and statistical parametric mapping analysis. Conclusion We successfully developed free-moving 18F-FDG-PET and 99mTc-HMPAO-SPECT imaging systems and detected detailed glucose uptake and cerebral blood flow changes in the conscious rat brain with fluoxetine administration. This system is expected to be useful to assess brain activity without the effects of anesthesia and tactual stimulation to evaluate drug effect or animal brain function.
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Liu F, Choi SR, Zha Z, Ploessl K, Zhu L, Kung HF. Deuterated 18F-9-O-hexadeutero-3-fluoropropoxyl-(+)-dihydrotetrabenazine (D6-FP-(+)-DTBZ): A vesicular monoamine transporter 2 (VMAT2) imaging agent. Nucl Med Biol 2017; 57:42-49. [PMID: 29306111 DOI: 10.1016/j.nucmedbio.2017.11.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 11/21/2017] [Accepted: 11/28/2017] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Vesicular monoamine transporters 2 (VMAT2) in the brain serve as transporter for packaging monoamine in vesicles for normal CNS neurotransmission. Several VMAT2 imaging agents, [11C]-(+)-DTBZ, dihydrotetrabenazine and [18F]FP-(+)-DTBZ (9-O-fluoropropyl-(+)-dihydro tetrabenazine, a.k.a. [18F]AV-133), are useful for studying the changes in brain function related to monoamine transmission by in vivo imaging. Deuterated analogs have been reported targeting VMAT2 binding sites. METHODS A novel deuterated [18F]9-O-hexaduterofluoropropyl-(+)-dihydrotetrabenazine, [18F]D6-FP-(+)-DTBZ, [18F]1, was prepared as a VMAT2 imaging agent. This 18F agent which targeted VMAT2 was evaluated by in vitro binding, in vivo biodistribution and microPET imaging studies in rodents. RESULTS The one step radiolabeling reaction led to the desired [18F]D6-FP-(+)-DTBZ, [18F]1, which showed excellent binding affinity to VMAT2 (Ki=0.32±0.07nM) comparable to that of FP-(+)-DTBZ (Ki=0.33±0.02nM) using [18F]FP-(+)-DTBZ and rat striatum membrane homogenates. In vivo biodistribution in normal rats showed that 1, exhibited excellent brain uptake and comparable high ratio of striatum to cerebellum (target/background) ratio at 1h after injection (ratio of 6.05±0.43 vs 5.66±0.72 for [18F]FP-(+)-DTBZ vs [18F]1, respectively). MicroPET imaging studies in rats further confirm that the striatum with high VMAT2 concentration was clearly delineated in normal rat brain after iv injection of [18F]1. We observed minor changes of metabolism in rat plasma between these two agents; however, the changes showed little effect on regional brain uptake and retention. CONCLUSIONS The results reported here lend support for using [18F]D6-FP-(+)-DTBZ, [18F]1, as in vivo PET imaging agent for VMAT2 binding in the brain.
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Affiliation(s)
- Futao Liu
- Key Laboratory of Radiopharmaceuticals, Beijing Normal University, Ministry of Education, Beijing 100875, PR China; Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Seok Rye Choi
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA; Five Eleven Pharma Inc., Philadelphia, PA 19104, USA
| | - Zhihao Zha
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Karl Ploessl
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA; Five Eleven Pharma Inc., Philadelphia, PA 19104, USA
| | - Lin Zhu
- Key Laboratory of Radiopharmaceuticals, Beijing Normal University, Ministry of Education, Beijing 100875, PR China; Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hank F Kung
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA; Five Eleven Pharma Inc., Philadelphia, PA 19104, USA.
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Structural requirement of C11b chirality of tetrabenazine analogs as VMAT2 imaging ligands: synthesis and in vivo evaluation. J Radioanal Nucl Chem 2017. [DOI: 10.1007/s10967-017-5333-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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