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Wongso H, Hendra R, Nugraha AS, Ritawidya R, Saptiama I, Kusumaningrum CE. Microbial metabolites diversity and their potential as molecular template for the discovery of new fluorescent and radiopharmaceutical probes. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Jauregui-Osoro M, De Robertis S, Halsted P, Gould SM, Yu Z, Paul RL, Marsden PK, Gee AD, Fenwick A, Blower PJ. Production of copper-64 using a hospital cyclotron: targetry, purification and quality analysis. Nucl Med Commun 2021; 42:1024-1038. [PMID: 34397988 PMCID: PMC8357037 DOI: 10.1097/mnm.0000000000001422] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 03/09/2021] [Indexed: 12/31/2022]
Abstract
OBJECTIVES To construct and evaluate a 64Cu production system that minimises the amount of costly 64Ni, radionuclidic impurities and nonradioactive metal contamination and maximises radiochemical and radionuclidic purity and molar activity; and to report analytical and quality control methods that can be used within typical PET radiochemistry production facilities to measure metal ion concentrations and radiometal molar activities. METHODS Low volume was ensured by dissolving the irradiated nickel in a low volume of hydrochloric acid (<1 mL) using the concave gold target backing as a reaction vessel in a custom-built target holder. Removal of contaminating 55Co and nonradioactive trace metals was ensured by adding an intermediate hydrochloric acid concentration step during the conventional ion-exchange elution process. The radionuclidic purity of the product was determined by half-life measurements, gamma spectroscopy and ion radiochromatography. Trace metal contamination and molar activity were determined by ion chromatography. RESULTS AND CONCLUSIONS On a small scale, suitable for preclinical research, the process produced typically 3.2 GBq 64Cu in 2 mL solution from 9.4 ± 2.1 mg nickel-64 electroplated onto a gold target backing. The product had high molar activity (121.5 GBq/µmol), was free of trace metal contamination detectable by ion chromatography and has been used for many preclinical and clinical PET imaging applications.
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Affiliation(s)
- Maite Jauregui-Osoro
- School of Biomedical Engineering and Imaging Sciences, King’s College London, School of Biomedical Engineering and Imaging Sciences, St Thomas’ Hospital
| | - Simona De Robertis
- School of Biomedical Engineering and Imaging Sciences, King’s College London, School of Biomedical Engineering and Imaging Sciences, St Thomas’ Hospital
| | - Philip Halsted
- School of Biomedical Engineering and Imaging Sciences, King’s College London, School of Biomedical Engineering and Imaging Sciences, St Thomas’ Hospital
| | - Sarah-May Gould
- School of Biomedical Engineering and Imaging Sciences, King’s College London, School of Biomedical Engineering and Imaging Sciences, St Thomas’ Hospital
| | - Zilin Yu
- School of Biomedical Engineering and Imaging Sciences, King’s College London, School of Biomedical Engineering and Imaging Sciences, St Thomas’ Hospital
| | - Rowena L Paul
- School of Biomedical Engineering and Imaging Sciences, King’s College London, School of Biomedical Engineering and Imaging Sciences, St Thomas’ Hospital
| | - Paul K Marsden
- School of Biomedical Engineering and Imaging Sciences, King’s College London, School of Biomedical Engineering and Imaging Sciences, St Thomas’ Hospital
| | - Antony D Gee
- School of Biomedical Engineering and Imaging Sciences, King’s College London, School of Biomedical Engineering and Imaging Sciences, St Thomas’ Hospital
| | - Andrew Fenwick
- National Physical Laboratory, Teddington, Middlesex, London, UK
| | - Philip J. Blower
- School of Biomedical Engineering and Imaging Sciences, King’s College London, School of Biomedical Engineering and Imaging Sciences, St Thomas’ Hospital
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Baark F, Shaughnessy F, Pell VR, Clark JE, Eykyn TR, Blower P, Southworth R. Tissue acidosis does not mediate the hypoxia selectivity of [ 64Cu][Cu(ATSM)] in the isolated perfused rat heart. Sci Rep 2019; 9:499. [PMID: 30679497 PMCID: PMC6346098 DOI: 10.1038/s41598-018-36145-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 11/15/2018] [Indexed: 01/16/2023] Open
Abstract
Copper-64-Diacetyl-bis(N4-methylthiosemicarbazone) [64Cu][Cu(ATSM)] is a hypoxia-targeting PET tracer with applications in oncology and cardiology. Upon entering a hypoxic cell, [64Cu][Cu(II)(ATSM)] is reduced to a putative [64Cu][Cu(I)(ATSM)]- species which dissociates to deposit radiocopper, thereby providing hypoxic contrast. This process may be dependent upon protonation arising from intracellular acidosis. Since acidosis is a hallmark of ischemic tissue and tumors, the hypoxia specificity of [64Cu][Cu(ATSM)] may be confounded by changes in intracellular pH. We have therefore determined the influence of intracellular pH on [64Cu][Cu(ATSM)] pharmacokinetics. Using isolated perfused rat hearts, acidosis was induced using an ammonium pre-pulse method, with and without hypoxic buffer perfusion. Cardiac [64Cu][Cu(ATSM)] pharmacokinetics were determined using NaI detectors, with intracellular pH and cardiac energetics monitored in parallel by 31P NMR. To distinguish direct acidotic effects on tracer pharmacokinetics from acidosis-induced hypocontractility, parallel studies used lidocaine perfusion to abolish cardiac contraction. Hypoxic myocardium trapped [64Cu][Cu(ATSM)] despite no evidence of it being acidotic when characterised by 31P NMR. Independent induction of tissue acidosis had no direct effect on [64Cu][Cu(ATSM)] pharmacokinetics in either normoxic or hypoxic hearts, beyond decreasing cardiac oxygen consumption to alleviate hypoxia and decrease tracer retention, leading us to conclude that tissue acidosis does not mediate the hypoxia selectivity of [64Cu][Cu(ATSM)].
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Affiliation(s)
- Friedrich Baark
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
- School of Cardiovascular Medicine and Sciences, BHF Centre, King's College London, London, UK
| | - Fiona Shaughnessy
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
| | - Victoria R Pell
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
- School of Cardiovascular Medicine and Sciences, BHF Centre, King's College London, London, UK
| | - James E Clark
- School of Cardiovascular Medicine and Sciences, BHF Centre, King's College London, London, UK
| | - Thomas R Eykyn
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
| | - Philip Blower
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
| | - Richard Southworth
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK.
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Pell VR, Baark F, Mota F, Clark JE, Southworth R. PET Imaging of Cardiac Hypoxia: Hitting Hypoxia Where It Hurts. CURRENT CARDIOVASCULAR IMAGING REPORTS 2018. [PMID: 29515752 PMCID: PMC5830463 DOI: 10.1007/s12410-018-9447-3] [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] [Indexed: 12/23/2022]
Abstract
Purpose of Review In this review, we outline the potential for hypoxia imaging as a diagnostic and prognostic tool in cardiology. We describe the lead hypoxia PET radiotracers currently in development and propose a rationale for how they should most appropriately be screened and validated. Recent Findings While the majority of hypoxia imaging agents has been developed for oncology, the requirements for hypoxia imaging in cardiology are different. Recent work suggests that the bis(thiosemicarbazone) family of compounds may be capable of detecting the subtle degrees of hypoxia associated with cardiovascular syndromes, and that they have the potential to be “tuned” to provide different tracers for different applications. Summary New tracers currently in development show significant promise for imaging evolving cardiovascular disease. Fundamental to their exploitation is their careful, considered validation and characterization so that the information they provide delivers the greatest prognostic insight achievable.
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Affiliation(s)
- Victoria R Pell
- 1School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Friedrich Baark
- 1School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Filipa Mota
- 1School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - James E Clark
- 2School of Cardiovascular Medicine and Sciences, BHF Centre, King's College London, London, UK
| | - Richard Southworth
- 1School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
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Abstract
Radiopharmaceuticals are widely accepted to be a very safe class of drugs, with very few adverse reactions and unexpected biodistributions. However, problems can arise because of technical issues in manufacture or reconstitution, patient preparation, or drug administration. This review presents highlights of issues that have arisen in the newer classes of radiopharmaceuticals in the last 20 years and expands the scope of the previous report to include PET and therapeutic radiopharmaceuticals. Variations in the "quality" of the eluate of a (99)Mo/(99m)Tc generator remain a major issue. Several of the newer (99m)Tc tracers require a heating step in preparation that can also lead to unacceptably low radiochemical purity. Radiolytic breakdown can be a problem with all classes of radiopharmaceuticals. Many of the newer radiopharmaceuticals localize by receptor- or transporter-mediated processes and thus can be affected by other drugs, making patient preparation more important than ever. Therapeutic radiopharmaceuticals may require coadministration of radioprotectant regimens, such as the use of lysine-arginine infusions with radiopeptide therapy. Extravasation can have serious consequences with therapeutic radiopharmaceuticals. Adverse reactions to newer radiopharmaceuticals remain rare, though may increase because of coadministration of agents such as contrast media. However, there is known to be underreporting of minor adverse reactions. Knowledge of the pitfalls that can occur with radiopharmaceuticals is important in the interpretation of nuclear medicine images and optimal patient care.
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Affiliation(s)
- James R Ballinger
- Department of Nuclear Medicine, Guy's and St Thomas' Hospital, London, UK; Division of Imaging Sciences, King's College London School of Medicine, London, UK.
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Lapi SE, Lewis JS, Dehdashti F. Evaluation of hypoxia with copper-labeled diacetyl-bis(N-methylthiosemicarbazone). Semin Nucl Med 2015; 45:177-85. [PMID: 25704389 DOI: 10.1053/j.semnuclmed.2014.10.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Imaging of hypoxia is important in many diseases states in oncology, cardiology, and neurology. The radiopharmaceutical, copper-labeled diacetyl-bis(N-methylthiosemicarbazone), has been used to assess hypoxia in many studies. In particular, copper-labeled diacetyl-bis(N-methylthiosemicarbazone) has been used in oncologic settings to investigate tumor hypoxia and the role of this parameter in response to therapy and outcome. Some groups have conducted imaging studies assessing the role of hypoxia in cardiovascular and neurologic disorders. Additionally, several groups have made significant progress into understanding the mechanism by which this compound accumulates in cells. Multiple preclinical and clinical studies have been conducted, shedding light on the importance of careful image analysis when using this tracer. This review article focuses on the recent preclinical and clinical studies with this tracer.
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Affiliation(s)
- Suzanne E Lapi
- Edward Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO; The Alvin J. Siteman Cancer Center, Washington University School of Medicine, St Louis, MO
| | - Jason S Lewis
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Farrokh Dehdashti
- Edward Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO; The Alvin J. Siteman Cancer Center, Washington University School of Medicine, St Louis, MO.
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Southworth R, Torres Martin de Rosales R, Meszaros LK, Ma MT, Mullen GED, Fruhwirth G, Young JD, Imberti C, Bagunya-Torres J, Andreozzi E, Blower PJ. Opportunities and challenges for metal chemistry in molecular imaging: from gamma camera imaging to PET and multimodality imaging. ADVANCES IN INORGANIC CHEMISTRY 2015; 68:1-41. [PMID: 30381783 PMCID: PMC6205628 DOI: 10.1016/bs.adioch.2015.09.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The development of medical imaging is a highly multidisciplinary endeavor requiring the close cooperation of clinicians, physicists, engineers, biologists and chemists to identify capabilities, conceive challenges and solutions and apply them in the clinic. The chemistry described in this article illustrates how synergistic advances in these areas drive the technology and its applications forward, with each discipline producing innovations that in turn drive innovations in the others. The main thread running through the article is the shift from single photon radionuclide imaging towards PET, and in turn the emerging shift from PET/CT towards PET/MRI and further, combination of these with optical imaging. Chemistry to support these transitions is exemplified by building on a summary of the status quo, and recent developments, in technetium-99m chemistry for SPECT imaging, followed by a report of recent developments to support clinical application of short lived (Ga-68) and long-lived (Zr-89) positron emitting isotopes, copper isotopes for PET imaging, and combined modality imaging agents based on radiolabelled iron oxide based nanoparticles.
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Affiliation(s)
- Richard Southworth
- King's College London, Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, London, UK
| | | | - Levente K Meszaros
- King's College London, Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, London, UK
| | - Michelle T Ma
- King's College London, Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, London, UK
| | - Gregory E D Mullen
- King's College London, Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, London, UK
| | - Gilbert Fruhwirth
- King's College London, Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, London, UK
| | - Jennifer D Young
- King's College London, Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, London, UK
| | - Cinzia Imberti
- King's College London, Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, London, UK
| | - Julia Bagunya-Torres
- King's College London, Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, London, UK
| | - Erica Andreozzi
- King's College London, Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, London, UK
| | - Philip J Blower
- King's College London, Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, London, UK
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Medina RA, Mariotti E, Pavlovic D, Shaw KP, Eykyn TR, Blower PJ, Southworth R. 64Cu-CTS: A Promising Radiopharmaceutical for the Identification of Low-Grade Cardiac Hypoxia by PET. J Nucl Med 2015; 56:921-6. [PMID: 25883129 DOI: 10.2967/jnumed.114.148353] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 03/26/2015] [Indexed: 01/23/2023] Open
Abstract
UNLABELLED The subtle hypoxia underlying chronic cardiovascular disease is an attractive target for PET imaging, but the lead hypoxia imaging agents (64)Cu-2,3-butanedione bis(N4-methylthiosemicarbazone) (ATSM) and (18)F-fluoromisonidazole are trapped only at extreme levels of hypoxia and hence are insufficiently sensitive for this purpose. We have therefore sought an analog of (64)Cu-ATSM better suited to identify compromised but salvageable myocardium, and we validated it using parallel biomarkers of cardiac energetics comparable to those observed in chronic cardiac ischemic syndromes. METHODS Rat hearts were perfused with aerobic buffer for 20 min, followed by a range of hypoxic buffers (using a computer-controlled gas mixer) for 45 min. Contractility was monitored by intraventricular balloon, energetics by (31)P nuclear MR spectroscopy, lactate and creatine kinase release spectrophotometrically, and hypoxia-inducible factor 1-α by Western blotting. RESULTS We identified a key hypoxia threshold at a 30% buffer O2 saturation that induces a stable and potentially survivable functional and energetic compromise: left ventricular developed pressure was depressed by 20%, and cardiac phosphocreatine was depleted by 65.5% ± 14% (P < 0.05 vs. control), but adenosine triphosphate levels were maintained. Lactate release was elevated (0.21 ± 0.067 mmol/L/min vs. 0.056 ± 0.01 mmol/L/min, P < 0.05) but not maximal (0.46 ± 0.117 mmol/L/min), indicating residual oxidative metabolic capacity. Hypoxia-inducible factor 1-α was elevated but not maximal. At this key threshold, (64)Cu-2,3-pentanedione bis(thiosemicarbazone) (CTS) selectively deposited significantly more (64)Cu than any other tracer we examined (61.8% ± 9.6% injected dose vs. 29.4% ± 9.5% for (64)Cu-ATSM, P < 0.05). CONCLUSION The hypoxic threshold that induced survivable metabolic and functional compromise was 30% O2. At this threshold, only (64)Cu-CTS delivered a hypoxic-to-normoxic contrast of 3:1, and it therefore warrants in vivo evaluation for imaging chronic cardiac ischemic syndromes.
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Affiliation(s)
- Rodolfo A Medina
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom; and
| | - Erika Mariotti
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom; and
| | - Davor Pavlovic
- Centre for Cardiovascular Sciences, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom
| | - Karen P Shaw
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom; and
| | - Thomas R Eykyn
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom; and
| | - Philip J Blower
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom; and
| | - Richard Southworth
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom; and
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Shaughnessy F, Mariotti E, Shaw KP, Eykyn TR, Blower PJ, Siow R, Southworth R. Modification of intracellular glutathione status does not change the cardiac trapping of (64)Cu(ATSM). EJNMMI Res 2014; 4:40. [PMID: 26055939 PMCID: PMC4883992 DOI: 10.1186/s13550-014-0040-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 07/05/2014] [Indexed: 02/07/2023] Open
Abstract
Background The trapping mechanisms of the PET hypoxia imaging agent copper(II)-diacetyl-bis(N4-methylthiosemicarbazone) (64Cu(ATSM)) remain unresolved, although its reduction prior to dissociation may be mediated by intracellular thiols. Glutathione (GSH) is the most abundant intracellular thiol, and its redox status changes in cancer cells and ischaemic myocardium (two prime applications for 64Cu(ATSM) PET). We therefore investigated whether modification of intracellular GSH content affects the hypoxia selectivity of 64Cu(ATSM). Methods Isolated rat hearts (n = five per group) were perfused with aerobic buffer (equilibrated with 95%O2/5%CO2) for 15 min, then hypoxic buffer (95%N2/5%CO2) for 20 min. Cardiac glutathione was depleted by buthionine sulphoximine (BSO, 4 mmol/kg/ 48 h intraperitoneal), or augmented by N-acetyl cysteine (NAC, 4 mmol/L) in the perfusion buffer. Cardiac 64Cu retention from three 2-MBq bolus injections of 64Cu(ATSM) before and during hypoxia was then monitored by NaI detectors. Results Cardiac GSH content was elevated by NAC and depleted by BSO (from 7.9 ± 2.0 to 59.3 ± 8.3 nmol/mg and 3.7 ± 1.0 nmol/mg protein, respectively; p < 0.05). Hypoxia did not affect cardiac GSH content in any group. During normoxia, tracer washed out bi-exponentially, with 13.1% ± 1.7% injected dose being retained; this was not affected by GSH augmentation or depletion. Hypoxia significantly increased tracer retention (to 59.1% ± 6.3%, p < 0.05); this effect was not modified by GSH augmentation or depletion. Conclusion Modification of GSH levels had no impact upon the pharmacokinetics or hypoxia selectivity of 64Cu(ATSM). While thiols may yet prove essential for the intracellular trapping of 64Cu(ATSM), they are not the determinants of its hypoxia selectivity. Electronic supplementary material The online version of this article (doi:10.1186/s13550-014-0040-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Fiona Shaughnessy
- Division of Imaging Sciences, The Rayne Institute, St. Thomas' Hospital, King's College London, Lambeth Palace Rd., London, SE1 7EH, UK,
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Handley MG, Medina RA, Mariotti E, Kenny GD, Shaw KP, Yan R, Eykyn TR, Blower PJ, Southworth R. Cardiac hypoxia imaging: second-generation analogues of 64Cu-ATSM. J Nucl Med 2014; 55:488-94. [PMID: 24421288 PMCID: PMC6214505 DOI: 10.2967/jnumed.113.129015] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
UNLABELLED Myocardial hypoxia is an attractive target for diagnostic and prognostic imaging, but current approaches are insufficiently sensitive for clinical use. The PET tracer copper(II)-diacetyl-bis(N4-methylthiosemicarbazone) ((64)Cu-ATSM) has promise, but its selectivity and sensitivity could be improved by structural modification. We have therefore evaluated a range of (64)Cu-ATSM analogs for imaging hypoxic myocardium. METHODS Isolated rat hearts (n = 5/group) were perfused with normoxic buffer for 30 min and then hypoxic buffer for 45 min within a custom-built triple-γ-detector system to quantify radiotracer infusion, hypoxia-dependent cardiac uptake, and washout. A 1-MBq bolus of each candidate tracer (and (18)F-fluoromisonidazole for comparative purposes) was injected into the arterial line during normoxia, and during early and late hypoxia, and their hypoxia selectivity and pharmacokinetics were evaluated. The in vivo pharmacokinetics of promising candidates in healthy rats were then assessed by PET imaging and biodistribution. RESULTS All tested analogs exhibited hypoxia sensitivity within 5 min. Complexes less lipophilic than (64)Cu-ATSM provided significant gains in hypoxic-to-normoxic contrast (14:1 for (64)Cu-2,3-butanedione bis(thiosemicarbazone) (ATS), 17:1 for (64)Cu-2,3-pentanedione bis(thiosemicarbazone) (CTS), 8:1 for (64)Cu-ATSM, P < 0.05). Hypoxic first-pass uptake was 78.2% ± 7.2% for (64)Cu-ATS and 70.7% ± 14.5% for (64)Cu-CTS, compared with 63.9% ± 11.7% for (64)Cu-ATSM. Cardiac retention of (18)F-fluoromisonidazole increased from 0.44% ± 0.17% during normoxia to 2.24% ± 0.08% during hypoxia. In vivo, normoxic cardiac retention of (64)Cu-CTS was significantly lower than that of (64)Cu-ATSM and (64)Cu-ATS (0.13% ± 0.02% vs. 0.25% ± 0.04% and 0.24% ± 0.03% injected dose, P < 0.05), with retention of all 3 tracers falling to less than 0.7% injected dose within 6 min. (64)Cu-CTS also exhibited lower uptake in liver and lung. CONCLUSION (64)Cu-ATS and (64)Cu-CTS exhibit better cardiac hypoxia selectivity and imaging characteristics than the current lead hypoxia tracers, (64)Cu-ATSM and (18)F-fluoromisonidazole.
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Affiliation(s)
- Maxwell G Handley
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom
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