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Else T, Wong KK, Frey KA, Brooks AF, Viglianti BL, Raffel DM. 3-[ 18F]Fluoro- para-hydroxyphenethylguanidine (3-[ 18F]pHPG) PET-A Novel Imaging Modality for Paraganglioma. J Endocr Soc 2024; 8:bvae049. [PMID: 38617812 PMCID: PMC11010306 DOI: 10.1210/jendso/bvae049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Indexed: 04/16/2024] Open
Abstract
Context Functional positron emission tomography (PET) imaging for the characterization of pheochromocytoma and paraganglioma (PCC/PGL) and for detection of metastases in malignant disease, offers valuable clinical insights that can significantly guide patient treatment. Objective This work aimed to evaluate a novel PET radiotracer, 3-[18F]fluoro-para-hydroxyphenethylguanidine (3-[18F]pHPG), a norepinephrine analogue, for its ability to localize PCC/PGL. Methods 3-[18F]pHPG PET/CT whole-body scans were performed on 16 patients (8 male:8 female; mean age 47.6 ± 17.6 years; range, 19-74 years) with pathologically confirmed or clinically diagnosed PCC/PGL. After intravenous administration of 304 to 475 MBq (8.2-12.8 mCi) of 3-[18F]pHPG, whole-body PET scans were performed at 90 minutes in all patients. 3-[18F]pHPG PET was interpreted for abnormal findings consistent with primary tumor or metastasis, and biodistribution in normal organs recorded. Standardized uptake value (SUV) measurements were obtained for target lesions and physiological organ distributions. Results 3-[18F]pHPG PET showed high radiotracer uptake and trapping in primary tumors, and metastatic tumor lesions that included bone, lymph nodes, and other solid organ sites. Physiological biodistribution was universally present in salivary glands (parotid, submandibular, sublingual), thyroid, heart, liver, adrenals, kidneys, and bladder. Comparison [68Ga]DOTATATE PET/CT was available in 10 patients and in all cases showed concordant distribution. Comparison [123I]meta-iodobenzylguanidine [123I]mIBG planar scintigraphy and SPECT/CT scans were available for 4 patients, with 3-[18F]pHPG showing a greater number of metastatic lesions. Conclusion We found the kinetic profile of 3-[18F]pHPG PET affords high activity retention within benign and metastatic PCC/PGL. Therefore, 3-[18F]pHPG PET imaging provides a novel modality for functional imaging and staging of malignant paraganglioma with advantages of high lesion affinity, whole-body coregistered computed tomography, and rapid same-day imaging.
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Affiliation(s)
- Tobias Else
- Endocrinology, Metabolism, and Diabetes, University of Michigan, Ann Arbor, MI 48109-5674, USA
| | - Ka Kit Wong
- Nuclear Medicine/Radiology, University of Michigan, Ann Arbor, MI 48109-0028, USA
| | - Kirk A Frey
- Nuclear Medicine/Radiology, University of Michigan, Ann Arbor, MI 48109-0028, USA
| | - Allen F Brooks
- Nuclear Medicine/Radiology, University of Michigan, Ann Arbor, MI 48109-0028, USA
| | - Benjamin L Viglianti
- Nuclear Medicine/Radiology, University of Michigan, Ann Arbor, MI 48109-0028, USA
| | - David M Raffel
- Nuclear Medicine/Radiology, University of Michigan, Ann Arbor, MI 48109-0028, USA
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Pakula RJ, Raffel DM, Koeppe RA, Winton WP, Stauff J, Bohnen NI, Albin RL, Scott PJH, Shao X. Automated production of [ 11C]butyrate for keto body PET imaging. Nucl Med Biol 2023; 116-117:108315. [PMID: 36680983 PMCID: PMC10053181 DOI: 10.1016/j.nucmedbio.2023.108315] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 12/07/2022] [Accepted: 01/02/2023] [Indexed: 01/15/2023]
Abstract
The report describes an updated, fully automated method for the production of [11C]butyrate, validated for use in clinical studies. A commercially available GE Tracerlab FXM synthesis module was reconfigured to allow for air-free introduction of n-propyl magnesium chloride and to incorporate Sep-Pak cartridges to simplify and shorten the purification process, as compared to purifying the product using traditional HPLC. The method takes 20 min from end-of-bombardment and reliably produces injectable doses of [11C]butyrate (8029 ± 1628 MBq (217 ± 44 mCi), 14 % radiochemical yield based on [11C]CO2, non-decay corrected) in high radiochemical purity (>97 %), n = 3. With radiotracer in hand, PET scans of rats confirmed uptake of the radiopharmaceutical in the brain. Rat biodistribution data was obtained and used in conjunction with OLINDA software to determine an estimated human total body effective dose of 3.20 × 10-3 mSv/MBq (1.19 × 10-2 rem/mCi), along with preliminary rodent PET imaging that confirmed brain uptake. Lastly, our first human [11C]butyrate PET studies using a dynamic bolus injection technique (n = 5), with a graphical Logan analysis using a white matter reference region, confirmed good radiotracer uptake in the brain and with relatively more prominent uptake in the cerebellar hemispheres, vermis, cingulum cortex and the thalami.
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Affiliation(s)
- Ryan J Pakula
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - David M Raffel
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Robert A Koeppe
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Wade P Winton
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Jenelle Stauff
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Nicolaas I Bohnen
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, United States of America; Department of Neurology, University of Michigan, Ann Arbor, MI 48109, United States of America; Neurology Service and Geriatrics Research, Education, and Clinical Center, Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, MI 48109, United States of America; University of Michigan, Morris K. Udall Parkinson's Disease Research Center of Excellence, Ann Arbor, MI 48109, United States of America; University of Michigan, Parkinson's Foundation Research Center of Excellence, Ann Arbor, MI, 48109, United States of America
| | - Roger L Albin
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, United States of America; Neurology Service and Geriatrics Research, Education, and Clinical Center, Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, MI 48109, United States of America; University of Michigan, Morris K. Udall Parkinson's Disease Research Center of Excellence, Ann Arbor, MI 48109, United States of America; University of Michigan, Parkinson's Foundation Research Center of Excellence, Ann Arbor, MI, 48109, United States of America
| | - Peter J H Scott
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, United States of America.
| | - Xia Shao
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, United States of America.
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Wong KK, Else T, Viglianti BL, Brooks AF, Frey KA, Raffel DM. PET imaging of metastatic paraganglioma using novel 3-[ 18F]fluoro-para-hydroxyphenethylguanidine (3-[ 18F]pHPG) radiotracer. Eur J Nucl Med Mol Imaging 2022; 49:2098-2099. [PMID: 35089374 DOI: 10.1007/s00259-021-05639-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 11/24/2021] [Indexed: 11/04/2022]
Affiliation(s)
- Ka Kit Wong
- Nuclear Medicine/Radiology, University of Michigan, Ann Arbor, MI, USA.
| | - Tobias Else
- Endocrinology, Metabolism, and Diabetes, University of Michigan Hospital, Ann Arbor, MI, USA
| | | | - Allen F Brooks
- Nuclear Medicine/Radiology, University of Michigan, Ann Arbor, MI, USA
| | - Kirk A Frey
- Nuclear Medicine/Radiology, University of Michigan, Ann Arbor, MI, USA
| | - David M Raffel
- Nuclear Medicine/Radiology, University of Michigan, Ann Arbor, MI, USA
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Raffel DM, Crawford TC, Jung YW, Koeppe RA, Gu G, Rothley J, Frey KA. Quantifying cardiac sympathetic denervation: first studies of 18F-fluorohydroxyphenethylguanidines in cardiomyopathy patients. Eur J Nucl Med Mol Imaging 2021; 49:619-631. [PMID: 34387718 DOI: 10.1007/s00259-021-05517-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 07/29/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE 4-18F-Fluoro-m-hydroxyphenethylguanidine (18F-4F-MHPG) and 3-18F-fluoro-p-hydroxyphenethylguanidine (18F-3F-PHPG) were developed for quantifying regional cardiac sympathetic nerve density using tracer kinetic analysis. The aim of this study was to evaluate their performance in cardiomyopathy patients. METHODS Eight cardiomyopathy patients were scanned with 18F-4F-MHPG and 18F-3F-PHPG. Also, regional resting perfusion was assessed with 13N-ammonia. 18F-4F-MHPG and 18F-3F-PHPG kinetics were analyzed using the Patlak graphical method to obtain Patlak slopes Kp (mL/min/g) as measures of regional nerve density. Patlak slope polar maps were used to evaluate the pattern and extent of cardiac denervation. For comparison, "retention index" (RI) values (mL blood/min/mL tissue) were also calculated and used to assess denervation. Perfusion polar maps were used to estimate the extent of hypoperfusion. RESULTS Patlak analysis of 18F-4F-MHPG and 18F-3F-PHPG kinetics was successful in all subjects, demonstrating the robustness of this approach in cardiomyopathy patients. Substantial regional denervation was observed in all subjects, ranging from 25 to 74% of the left ventricle. Denervation zones were equal to or larger than the size of corresponding areas of hypoperfusion. The two tracers provided comparable metrics of regional nerve density and the extent of left ventricular denervation. 18F-4F-MHPG exhibited faster liver clearance than 18F-3F-PHPG, reducing spillover from the liver into the inferior wall. 18F-4F-MHPG was also metabolized more consistently in plasma, which may allow application of population-averaged metabolite corrections. CONCLUSION The advantages of 18F-4F-MHPG (more rapid liver clearance, more consistent metabolism in plasma) make it the better imaging agent to carry forward into future clinical studies in patients with cardiomyopathy. TRIAL REGISTRATION Registered at the ClinicalTrials.gov website (NCT02669563). URL: https://clinicaltrials.gov/ct2/show/NCT02669563.
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Affiliation(s)
- David M Raffel
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School, 2276 Medical Science I, 1301 Catherine St., Ann Arbor, MI, 48109-5610, USA.
| | - Thomas C Crawford
- Division of Cardiology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Yong-Woon Jung
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School, 2276 Medical Science I, 1301 Catherine St., Ann Arbor, MI, 48109-5610, USA
| | - Robert A Koeppe
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School, 2276 Medical Science I, 1301 Catherine St., Ann Arbor, MI, 48109-5610, USA
| | - Guie Gu
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School, 2276 Medical Science I, 1301 Catherine St., Ann Arbor, MI, 48109-5610, USA
| | - Jill Rothley
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School, 2276 Medical Science I, 1301 Catherine St., Ann Arbor, MI, 48109-5610, USA
| | - Kirk A Frey
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School, 2276 Medical Science I, 1301 Catherine St., Ann Arbor, MI, 48109-5610, USA
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Zhao AY, Brooks AF, Raffel DM, Stauff J, Arteaga J, Scott PJH, Shao X. Fully Automated Radiosynthesis of [ 11C]Guanidines for Cardiac PET Imaging. ACS Med Chem Lett 2020; 11:2325-2330. [PMID: 33214848 DOI: 10.1021/acsmedchemlett.0c00479] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 09/30/2020] [Indexed: 02/07/2023] Open
Abstract
Radiolabeled guanidines such as meta-iodobenzylguanidine (MIBG) find utility in nuclear medicine as both diagnostic imaging agents and radiotherapeutics and, over the years, numerous methods for incorporating radionuclides into guanidines have been developed. In connection with a project developing new positron emission tomography (PET) radiotracers for cardiac sympathetic nerve density, we had cause to prepare [11C]3F-PHPOG. However, it quickly became apparent that radiolabeling of guanidine scaffolds with carbon-11 has remained challenging, and historical methods lack compatibility with modern automated radiochemistry synthesis platforms and current Good Manufacturing Practice (cGMP) requirements. To address this challenge, we report a new automated method for radiolabeling guanidines with carbon-11. The method was used to prepare a series of [11C]guanidines in good radiochemical yield (8-76% by radio-HPLC) and was found to have broad substrate scope and tolerance of unprotected OH and NH functional groups. The method was used to synthesize [11C]3F-PHPOG for preclinical imaging, and suitability of the radiotracer for preclinical use was demonstrated through preliminary cardiac PET in New Zealand white rabbits which revealed good cardiac uptake and expected retention in the heart.
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Affiliation(s)
- Austin Y. Zhao
- Department of Radiology, University of Michigan, Ann Arbor Michigan 48109, United States
| | - Allen F. Brooks
- Department of Radiology, University of Michigan, Ann Arbor Michigan 48109, United States
| | - David M. Raffel
- Department of Radiology, University of Michigan, Ann Arbor Michigan 48109, United States
| | - Jenelle Stauff
- Department of Radiology, University of Michigan, Ann Arbor Michigan 48109, United States
| | - Janna Arteaga
- Department of Radiology, University of Michigan, Ann Arbor Michigan 48109, United States
| | - Peter J. H. Scott
- Department of Radiology, University of Michigan, Ann Arbor Michigan 48109, United States
- Departments of Pharmacology and Medicinal Chemistry, University of Michigan, Ann Arbor Michigan 48109, United States
| | - Xia Shao
- Department of Radiology, University of Michigan, Ann Arbor Michigan 48109, United States
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Jackson IM, Lee SJ, Sowa AR, Rodnick ME, Bruton L, Clark M, Preshlock S, Rothley J, Rogers VE, Botti LE, Henderson BD, Hockley BG, Torres J, Raffel DM, Brooks AF, Frey KA, Kilbourn MR, Koeppe RA, Shao X, Scott PJH. Use of 55 PET radiotracers under approval of a Radioactive Drug Research Committee (RDRC). EJNMMI Radiopharm Chem 2020; 5:24. [PMID: 33175263 PMCID: PMC7658275 DOI: 10.1186/s41181-020-00110-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 10/19/2020] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND In the US, EU and elsewhere, basic clinical research studies with positron emission tomography (PET) radiotracers that are generally recognized as safe and effective (GRASE) can often be conducted under institutional approval. For example, in the United States, such research is conducted under the oversight of a Radioactive Drug Research Committee (RDRC) as long as certain requirements are met. Firstly, the research must be for basic science and cannot be intended for immediate therapeutic or diagnostic purposes, or to determine the safety and effectiveness of the PET radiotracer. Secondly, the PET radiotracer must be generally recognized as safe and effective. Specifically, the mass dose to be administered must not cause any clinically detectable pharmacological effect in humans, and the radiation dose to be administered must be the smallest dose practical to perform the study and not exceed regulatory dose limits within a 1-year period. In our experience, the main barrier to using a PET radiotracer under RDRC approval is accessing the required information about mass and radioactive dosing. RESULTS The University of Michigan (UM) has a long history of using PET radiotracers in clinical research studies. Herein we provide dosing information for 55 radiotracers that will enable other PET Centers to use them under the approval of their own RDRC committees. CONCLUSIONS The data provided herein will streamline future RDRC approval, and facilitate further basic science investigation of 55 PET radiotracers that target functionally relevant biomarkers in high impact disease states.
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Affiliation(s)
- Isaac M Jackson
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI, 48109, USA
- Present Address: Stanford University, Stanford, CA, USA
| | - So Jeong Lee
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI, 48109, USA
- Present Address: Gordon Center for Medical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Alexandra R Sowa
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI, 48109, USA
| | - Melissa E Rodnick
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI, 48109, USA
| | - Laura Bruton
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI, 48109, USA
| | - Mara Clark
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI, 48109, USA
| | - Sean Preshlock
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI, 48109, USA
| | - Jill Rothley
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI, 48109, USA
| | - Virginia E Rogers
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI, 48109, USA
| | - Leslie E Botti
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI, 48109, USA
| | - Bradford D Henderson
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI, 48109, USA
| | - Brian G Hockley
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI, 48109, USA
| | - Jovany Torres
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI, 48109, USA
| | - David M Raffel
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI, 48109, USA
| | - Allen F Brooks
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI, 48109, USA
| | - Kirk A Frey
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI, 48109, USA
| | - Michael R Kilbourn
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI, 48109, USA
| | - Robert A Koeppe
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI, 48109, USA
| | - Xia Shao
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI, 48109, USA
| | - Peter J H Scott
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI, 48109, USA.
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Kramer V, Brooks AF, Haeger A, Kuljis RO, Rafique W, Koeppe RA, Raffel DM, Frey KA, Amaral H, Scott PJH, Riss PJ. Evaluation of [ 18F]- N-Methyl lansoprazole as a Tau PET Imaging Agent in First-in-Human Studies. ACS Chem Neurosci 2020; 11:427-435. [PMID: 31898886 DOI: 10.1021/acschemneuro.9b00639] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Development of positron emission tomography (PET) imaging agents capable of quantifying tau aggregates in neurodegenerative disorders such as Alzheimer's disease (AD) is of enormous importance in the field of dementia research. The aim of the present study was to conduct first-in-man imaging studies with the potential novel tau imaging agent [18F]N-methyl lansoprazole ([18F]NML). Herein we report validation of the synthesis of [18F]NML for clinical use by labeling the trifluoromethyl group via radiofluorination of the corresponding gem-difluoro enol ether precursor. This is the first use of this method for clinical production of PET radiotracers and confirmed that it can be readily implemented at multiple production facilities to provide [18F]NML in good noncorrected radiochemical yield (3.4 ± 1.5 GBq, 4.6% ± 2.6%) and molar activity (120.1 ± 186.3 GBq/μmol), excellent radiochemical purity (>97%), and suitable for human use (n = 15). With [18F]NML in hand, we conducted rodent biodistribution, estimates of human dosimetry, and preliminary evaluation of [18F]NML in human subjects at two imaging sites. Healthy controls (n = 4) and mildly cognitively impaired (MCI) AD patients (n = 6) received [18F]NML (tau), [18F]AV1451 (tau), and [18F]florbetaben or [18F]florbetapir (amyloid) PET scans. A single progressive supranuclear palsy (PSP) patient also received [18F]NML and [18F]AV1451 PET scans. [18F]NML showed good brain uptake, reasonable pharmacokinetics, and appropriate imaging characteristics in healthy controls. The mean ± SD of the administered mass of [18F/19F]NML was 2.01 ± 2.17 μg (range, 0.16-8.27 μg) and the mean administered activity was 350 ± 62 MBq (range, 199-403 MBq). There were no adverse or clinically detectable pharmacologic effects in any of the 11 subjects, and no significant changes in vital signs were observed. However, despite high affinity for tau in vitro, brain retention in MCI/AD and PSP patients was low, and there was no evidence of specific signals in vivo that corresponded to tau. Although it is still unclear why clinical translation of the radiotracer was unsuccessful, we nevertheless conclude that further development of [18F]NML as a tau PET imaging agent is not warranted at this time.
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Affiliation(s)
- Vasko Kramer
- Center for Nuclear Medicine & PET/CT Positronmed, Providencia, 7501068 Santiago, Chile
- Positronpharma SA, Providencia, 7500921 Santiago Chile
| | - Allen F. Brooks
- Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Arlette Haeger
- Center for Nuclear Medicine & PET/CT Positronmed, Providencia, 7501068 Santiago, Chile
| | - Rodrigo O. Kuljis
- Center for Nuclear Medicine & PET/CT Positronmed, Providencia, 7501068 Santiago, Chile
| | - Waqas Rafique
- realomics SRI, Kjemisk Institutt, Universitetet i Oslo, Sem Sælands vei 26, Kjemibygningen, 0371 Oslo, Norway
| | - Robert A. Koeppe
- Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - David M. Raffel
- Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Kirk A. Frey
- Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Horacio Amaral
- Center for Nuclear Medicine & PET/CT Positronmed, Providencia, 7501068 Santiago, Chile
- Positronpharma SA, Providencia, 7500921 Santiago Chile
| | - Peter J. H. Scott
- Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Patrick J. Riss
- realomics SRI, Kjemisk Institutt, Universitetet i Oslo, Sem Sælands vei 26, Kjemibygningen, 0371 Oslo, Norway
- Klinik for Kirurgi og Nevrofag, Oslo Universitets Sykehus HF−Rikshospitalet, Postboks
4950 Nydalen, 0424 Oslo, Norway
- Norsk Medisinsk Syklotronsenter AS, Gaustad, Postboks
4950 Nydalen, 0424 Oslo, Norway
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Jang KS, Lee SS, Oh YH, Lee SH, Kim SE, Kim DW, Lee BC, Lee S, Raffel DM. Control of reactivity and selectivity of guanidinyliodonium salts toward 18F-Labeling by monitoring of protecting groups: Experiment and theory. J Fluor Chem 2019. [DOI: 10.1016/j.jfluchem.2019.109387] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Abstract
BACKGROUND Disease-induced damage to cardiac autonomic nerve populations is associated with an increased risk of sudden cardiac death. The extent of cardiac sympathetic denervation, assessed using planar scintigraphy or positron emission tomography, has been shown to predict the risk of arrhythmic events in heart failure patients staged for implantable cardioverter defibrillator therapy. The goal of this study was to perform first-in-human evaluations of 4-[18F]fluoro-meta-hydroxyphenethylguanidine and 3-[18F]fluoro-para-hydroxyphenethylguanidine, 2 new positron emission tomography radiotracers developed for quantifying regional cardiac sympathetic nerve density. METHODS AND RESULTS Cardiac positron emission tomography studies with 4-[18F]fluoro-meta-hydroxyphenethylguanidine and 3-[18F]fluoro-para-hydroxyphenethylguanidine were performed in normal subjects (n=4 each) to assess their imaging properties and organ kinetics. Patlak graphical analysis of their myocardial kinetics was evaluated as a technique for generating nerve density metrics. Whole-body biodistribution studies (n=4 each) were acquired and used to calculate human radiation dosimetry estimates. Patlak analysis proved to be an effective approach for quantifying regional nerve density. Using 960 left ventricular volumes of interest, across-subject Patlak slopes averaged 0.107±0.010 mL/min per gram for 4-[18F]fluoro-meta-hydroxyphenethylguanidine and 0.116±0.010 mL/min per gram for 3-[18F]fluoro-para-hydroxyphenethylguanidine. Tracer uptake was highest in heart, liver, kidneys, and salivary glands. Urinary excretion was the main elimination pathway. CONCLUSIONS 4-[18F]fluoro-meta-hydroxyphenethylguanidine and 3-[18F]fluoro-para-hydroxyphenethylguanidine each produce high-quality positron emission tomography images of the distribution of sympathetic nerves in human heart. Patlak analysis provides reproducible measurements of regional cardiac sympathetic nerve density at high spatial resolution. Further studies of these tracers in heart failure patients will be performed to identify the best agent for clinical development. CLINICAL TRIAL REGISTRATION URL: https://www.clinicaltrials.gov . Unique identifier: NCT02385877.
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Affiliation(s)
- David M Raffel
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School (D.M.R., Y.-W.J., R.A.K., K.S.J., G.G., P.J.H.S., J.R., K.A.F.)
| | - Yong-Woon Jung
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School (D.M.R., Y.-W.J., R.A.K., K.S.J., G.G., P.J.H.S., J.R., K.A.F.)
| | - Robert A Koeppe
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School (D.M.R., Y.-W.J., R.A.K., K.S.J., G.G., P.J.H.S., J.R., K.A.F.)
| | - Keun Sam Jang
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School (D.M.R., Y.-W.J., R.A.K., K.S.J., G.G., P.J.H.S., J.R., K.A.F.)
| | - Guie Gu
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School (D.M.R., Y.-W.J., R.A.K., K.S.J., G.G., P.J.H.S., J.R., K.A.F.)
| | - Peter J H Scott
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School (D.M.R., Y.-W.J., R.A.K., K.S.J., G.G., P.J.H.S., J.R., K.A.F.)
| | - Venkatesh L Murthy
- Division of Cardiovascular Medicine, Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan Medical School, Ann Arbor (V.L.M.)
| | - Jill Rothley
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School (D.M.R., Y.-W.J., R.A.K., K.S.J., G.G., P.J.H.S., J.R., K.A.F.)
| | - Kirk A Frey
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School (D.M.R., Y.-W.J., R.A.K., K.S.J., G.G., P.J.H.S., J.R., K.A.F.)
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10
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Jung YW, Gu G, Raffel DM. Improved synthesis of 4-[ 18 F]fluoro-m-hydroxyphenethylguanidine using an iodonium ylide precursor. J Labelled Comp Radiopharm 2019; 62:835-842. [PMID: 31361048 DOI: 10.1002/jlcr.3791] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/18/2019] [Accepted: 07/22/2019] [Indexed: 11/11/2022]
Abstract
Fluorine-18 labeled hydroxyphenethylguanidines were recently developed in our laboratory as a new class of PET radiopharmaceuticals for quantifying regional cardiac sympathetic nerve density in heart disease patients. Studies of 4-[18 F]fluoro-m-hydroxyphenethylguanidine ([18 F]4F-MHPG) and 3-[18 F]fluoro-p-hydroxyphenethylguanidine ([18 F]3F-PHPG) in human subjects have shown that these radiotracers can be used to generate high-resolution maps of regional sympathetic nerve density using the Patlak graphical method. Previously, these compounds were synthesized using iodonium salt precursors, which provided sufficient radiochemical yields for on-site clinical PET studies. However, we were interested in exploring new methods that could offer significantly higher radiochemical yields. Spirocyclic iodonium ylide precursors have recently been established as an attractive new approach to radiofluorination of electron-rich aromatic compounds, offering several advantages over iodonium salt precursors. The goal of this study was to prepare a spirocyclic iodonium ylide precursor for synthesizing [18 F]4F-MHPG and evaluate its efficacy in production of this radiopharmaceutical. Under optimized automated reaction conditions, the iodonium ylide precursor provided radiochemical yields averaging 7.8% ± 1.4% (n = 8, EOS, not decay corrected), around threefold higher than those achieved previously using an iodonium salt precursor. With further optimization and scale-up, this approach could potentially support commercial distribution of [18 F]4F-MHPG to PET centers without on-site radiochemistry facilities.
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Affiliation(s)
- Yong-Woon Jung
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Guie Gu
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - David M Raffel
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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11
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Pennathur S, Jaiswal M, Vivekanandan-Giri A, White EA, Ang L, Raffel DM, Rubenfire M, Pop-Busui R. Structured lifestyle intervention in patients with the metabolic syndrome mitigates oxidative stress but fails to improve measures of cardiovascular autonomic neuropathy. J Diabetes Complications 2017; 31:1437-1443. [PMID: 28709739 PMCID: PMC5580245 DOI: 10.1016/j.jdiacomp.2017.03.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 03/20/2017] [Accepted: 03/22/2017] [Indexed: 01/03/2023]
Abstract
AIMS To assess the role of oxidative stress in mediating adverse outcomes in metabolic syndrome (MetS) and resultant cardiovascular autonomic neuropathy (CAN), and to evaluate the effects of lifestyle interventions on measures of oxidative stress and CAN in subjects with MetS. METHODS Pilot study in 25 non-diabetic subjects with MetS (age 49±10years, 76% females) participating in a 24-week lifestyle intervention (supervised aerobic exercise/Mediterranean diet), and 25 age-matched healthy controls. CAN was assessed by cardiovascular reflex tests, heart rate variability (HRV) and PET imaging with sympathetic analog [11C] meta-hydroxyephedrine ([11C]HED). Specific oxidative fingerprints were measured by liquid-chromatography/mass-spectrometry (LC/MS). RESULTS At baseline, MetS subjects had significantly higher oxidative stress markers [3-nitrotyrosine (234±158 vs. 54±47μmol/mol tyrosine), ortho-tyrosine (59±38 vs. 18±10μmol/molphenylalanine, all P<0.0001], and impaired HRV at rest and during deep breathing (P=0.039 and P=0.021 respectively) compared to controls. Twenty-four-week lifestyle intervention significantly reduced all oxidative stress markers (all P<0.01) but did not change any of the CAN measures. CONCLUSIONS Subjects with MetS present with signs of CAN and increased oxidative stress in the absence of diabetes. The 24-week lifestyle intervention was effective in ameliorating oxidative stress, but did not improve measures of CAN. Larger clinical trials with longer duration are required to confirm these findings.
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Affiliation(s)
- Subramaniam Pennathur
- Department of Internal Medicine and Molecular and Integrative Physiology, Division of Nephrology, University of Michigan, Ann Arbor, MI, United States
| | - Mamta Jaiswal
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | | | - Elizabeth A White
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States
| | - Lynn Ang
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, University of Michigan, Ann Arbor, MI, United States
| | - David M Raffel
- Department of Radiology, Division of Nuclear Medicine, University of Michigan, Ann Arbor, MI, United States
| | - Melvyn Rubenfire
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI, United States
| | - Rodica Pop-Busui
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, University of Michigan, Ann Arbor, MI, United States.
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12
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Jung YW, Jang KS, Gu G, Koeppe RA, Sherman PS, Quesada CA, Raffel DM. [ 18F]Fluoro-Hydroxyphenethylguanidines: Efficient Synthesis and Comparison of Two Structural Isomers as Radiotracers of Cardiac Sympathetic Innervation. ACS Chem Neurosci 2017; 8:1530-1542. [PMID: 28322043 DOI: 10.1021/acschemneuro.7b00051] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Fluorine-18 labeled phenethylguanidines are currently under development in our laboratory as radiotracers for quantifying regional cardiac sympathetic nerve density using PET imaging techniques. In this study, we report an efficient synthesis of 18F-hydroxyphenethylguanidines consisting of nucleophilic aromatic [18F]fluorination of a protected diaryliodonium salt precursor followed by a single deprotection step to afford the desired radiolabeled compound. This approach has been shown to reliably produce 4-[18F]fluoro-m-hydroxyphenethylguanidine ([18F]4F-MHPG, [18F]1) and its structural isomer 3-[18F]fluoro-p-hydroxyphenethylguanidine ([18F]3F-PHPG, [18F]2) with good radiochemical yields. Preclinical evaluations of [18F]2 in nonhuman primates were performed to compare its imaging properties, metabolism, and myocardial kinetics with those obtained previously with [18F]1. The results of these studies have demonstrated that [18F]2 exhibits imaging properties comparable to those of [18F]1. Myocardial tracer kinetic analysis of each tracer provides quantitative metrics of cardiac sympathetic nerve density. Based on these findings, first-in-human PET studies with [18F]1 and [18F]2 are currently in progress to assess their ability to accurately measure regional cardiac sympathetic denervation in patients with heart disease, with the ultimate goal of selecting a lead compound for further clinical development.
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Affiliation(s)
- Yong-Woon Jung
- Division of Nuclear Medicine, Department
of Radiology, 2276 Medical
Sciences I Building, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Keun Sam Jang
- Division of Nuclear Medicine, Department
of Radiology, 2276 Medical
Sciences I Building, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Guie Gu
- Division of Nuclear Medicine, Department
of Radiology, 2276 Medical
Sciences I Building, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Robert A. Koeppe
- Division of Nuclear Medicine, Department
of Radiology, 2276 Medical
Sciences I Building, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Phillip S. Sherman
- Division of Nuclear Medicine, Department
of Radiology, 2276 Medical
Sciences I Building, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Carole A. Quesada
- Division of Nuclear Medicine, Department
of Radiology, 2276 Medical
Sciences I Building, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - David M. Raffel
- Division of Nuclear Medicine, Department
of Radiology, 2276 Medical
Sciences I Building, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
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13
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Duvernoy CS, Raffel DM, Swanson SD, Jaiswal M, Mueller G, Ibrahim ES, Pennathur S, Plunkett C, Stojanovska J, Brown MB, Pop-Busui R. Left ventricular metabolism, function, and sympathetic innervation in men and women with type 1 diabetes. J Nucl Cardiol 2016; 23:960-969. [PMID: 27146882 PMCID: PMC5103640 DOI: 10.1007/s12350-016-0434-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 01/29/2016] [Indexed: 01/09/2023]
Abstract
BACKGROUND In type I diabetes (T1DM), alterations in LV function may occur due to changes in innervation, metabolism, and efficiency. OBJECTIVES We evaluated the association between sympathetic nerve function, oxidative metabolism, resting blood flow, LV efficiency and function in healthy diabetics, and assessed gender differences. METHODS Cross-sectional study of 45 subjects with T1DM, 60% females, age 34 ± 13 years, and 10 age-matched controls. Positron emission tomography (PET) imaging with [(11)C]acetate and [(11)C]meta-hydroxyephedrine was performed, in addition to cardiac magnetic resonance imaging. RESULTS There were no significant differences in LV function, innervation, or oxidative metabolism between T1DM and controls. Cardiac oxidative metabolism was positively associated with higher levels of sympathetic activation, particularly in women. Diabetic women had significantly lower efficiency compared with diabetic men. Resting flow was significantly higher in diabetic women compared with diabetic men, and tended to be higher in female controls as well. CONCLUSIONS Measures of myocardial function, metabolism, blood flow, and sympathetic activation were preserved in young, otherwise healthy, T1DM patients. However, T1DM women presented with greater myocardial oxidative metabolism requirements than men. Ongoing studies are evaluating changes over time.
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Affiliation(s)
- Claire S Duvernoy
- Cardiology Section, VA Ann Arbor Healthcare System, Ann Arbor, MI, USA
- Division of Cardiology, University of Michigan, Ann Arbor, MI, USA
| | - David M Raffel
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA
| | - Scott D Swanson
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA
| | - Mamta Jaiswal
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan, 5329 Brehm Tower, 1000 Wall Street, Ann Arbor, MI, 48105, USA
| | - Gisela Mueller
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA
| | - El-Sayed Ibrahim
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA
| | - Subramaniam Pennathur
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Cynthia Plunkett
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan, 5329 Brehm Tower, 1000 Wall Street, Ann Arbor, MI, 48105, USA
| | | | - Morton B Brown
- Department of Biostatistics, University of Michigan, Ann Arbor, MI, USA
| | - Rodica Pop-Busui
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan, 5329 Brehm Tower, 1000 Wall Street, Ann Arbor, MI, 48105, USA.
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14
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Wong KK, Raffel DM, Bohnen NI, Altinok G, Gilman S, Frey KA. 2-Year Natural Decline of Cardiac Sympathetic Innervation in Idiopathic Parkinson Disease Studied with 11C-Hydroxyephedrine PET. J Nucl Med 2016; 58:326-331. [PMID: 27539837 DOI: 10.2967/jnumed.116.176891] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 07/21/2016] [Indexed: 01/24/2023] Open
Abstract
The objective of this study was to detect regional patterns of cardiac sympathetic denervation in idiopathic Parkinson disease (IPD) using 11C-hydroxyephedrine (11C-HED) PET and determine the denervation rate over 2 y. METHODS We obtained 62 cardiac 11C-HED PET scans in 39 patients (30 men and 9 women; mean age ± SD, 61.9 ± 5.9 y), including 23 patients with follow-up scans at 2 y. We derived 11C-HED retention indices (RIs; mL of blood/min/mL of tissue) reflecting nerve density and integrity for 480 left ventricular (LV) sectors. We compared IPD patients with 33 healthy controls using z score analysis; RI values ≤ 2.5 SDs were considered abnormal. We expressed global and regional LV denervation as the percentage extent of z score severity and severity-extent product (SEP) on 9-segment bullseye maps and decline in cardiac sympathetic innervation as the 2-y difference in SEP (diff-SEP). RESULTS Baseline 11C-HED PET in the 39 IPD patients revealed an RI mean of 0.052 ± 0.022 mL of blood/min/mL of tissue. In comparison with data from normal controls, 12 patients had normal 11C-HED PET, 5 showed mild denervation (percentage extent < 30%), and 22 had moderate to severe denervation (percentage extent > 30%, z score ≤ 2.5 SD). In the 23 paired PET scans, worsening cardiac denervation (global diff-SEP > 9) occurred in 14 of 23 (60.9%) patients over 2 y, including percentage LV abnormality (59% increasing to 66%), z-severity (-2.4 down to -2.5), and SEP (-195 to -227) (P = 0.0062). We found a mean annual decline of 4.6% ± 5.6 (maximum, 13%) in 11C-HED retention from a baseline global RI mean of 0.0481 ± 0.0218 to 0.0432 ± 0.0220 (P = 0.0009). At baseline, 5 patients with normal uptake had no interval change; 3 with mild denervation developed interval decline in lateral and inferior segments (diff-SEP -82 to -99) compared with anterior and septal segments (-65 to -79), whereas the reverse pattern occurred in 15 patients with severe baseline denervation. CONCLUSION Progressive decline in cardiac sympathetic neural integrity in IPD patients occurs at a modest rate over 2 y on 11C-HED scans with marked heterogeneity and a regional pattern of involvement and decline.
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Affiliation(s)
- Ka Kit Wong
- Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor, Michigan .,VA Ann Arbor Healthcare System, GRECC, Ann Arbor, Michigan
| | - David M Raffel
- Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor, Michigan
| | - Nicolaas I Bohnen
- Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor, Michigan.,VA Ann Arbor Healthcare System, GRECC, Ann Arbor, Michigan.,Functional Neuroimaging, Cognitive and Mobility Laboratory, Departments of Radiology and Neurology, University of Michigan, Ann Arbor, Michigan.,University of Michigan Morris K. Udall Center of Excellence for Parkinson's Disease Research, Ann Arbor, Michigan
| | - Gulcin Altinok
- Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor, Michigan
| | - Sid Gilman
- Department of Neurology, University of Michigan (retired), Ann Arbor, Michigan; and
| | - Kirk A Frey
- Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor, Michigan.,Department of Neurology, University of Michigan, Ann Arbor, Michigan
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15
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Raffel DM, Kilbourn MR, Koeppe RA. Donald M. Wieland, Ph.D. Nucl Med Biol 2015; 42:213-4. [DOI: 10.1016/j.nucmedbio.2014.11.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 11/25/2014] [Indexed: 10/24/2022]
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16
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Petrou M, Frey KA, Kilbourn MR, Scott PJH, Raffel DM, Bohnen NI, Müller MLTM, Albin RL, Koeppe RA. In vivo imaging of human cholinergic nerve terminals with (-)-5-(18)F-fluoroethoxybenzovesamicol: biodistribution, dosimetry, and tracer kinetic analyses. J Nucl Med 2014; 55:396-404. [PMID: 24481024 DOI: 10.2967/jnumed.113.124792] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED (-)-5-(18)F-fluoroethoxybenzovesamicol ((18)F-FEOBV) is a vesamicol derivative that binds selectively to the vesicular acetylcholine transporter (VAChT) and has been used in preclinical studies to quantify presynaptic cholinergic nerve terminals. This study presents, to our knowledge, the first-in-human experience with (18)F-FEOBV, including radiation dosimetry, biodistribution, tolerability and safety in human subjects, and brain kinetics and methods for quantitative analysis of (18)F-FEOBV. METHODS Whole-body (18)F-FEOBV scans were obtained in 3 healthy human volunteers. Seven additional subjects underwent dynamic brain imaging 0-120, 150-180, and 210-240 min after bolus injection of (18)F-FEOBV. Arterial blood sampling was performed with chromatographic identification of authentic (18)F-FEOBV to determine the arterial plasma input function. Analysis methods included nonlinear least-squares fitting of a 2-tissue-compartmental model, reference tissue modeling, and late single-scan imaging. RESULTS No pharmacologic or physiologic changes were observed after intravenous administration of up to 1.3 μg of (18)F-FEOBV. Radiation dosimetry estimates indicate that more than 400 MBq may be administered without exceeding regulatory radiation dose limits. Kinetic analysis showed brain uptake to be relatively high with single-pass extraction of 25%-35%. VAChT binding estimates varied by a factor of greater than 30 between the striatum and cortex. Coefficients of variation in k3 estimates varied from 15% to 30%. Volume of distribution measures yielded a dynamic range of approximately 15 but with little reduction in variability. Reference tissue approaches yielded more stable estimates of the distribution volume ratio (1 + BPND), with coefficients of variation ranging from 20% in the striatum to 6%-12% in cortical regions. The late static distribution of (18)F-FEOBV correlated highly with the distribution volume ratio estimates from reference tissue models (r = 0.993). CONCLUSION (18)F-FEOBV PET confirms that the tracer binds to VAChT with the expected in vivo human brain distribution. Both reference tissue modeling and late static scanning approaches provide a robust index of VAChT binding.
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Affiliation(s)
- Myria Petrou
- Department of Radiology, Division of Nuclear Medicine, University of Michigan Medical School, Ann Arbor, Michigan
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17
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Jang KS, Jung YW, Gu G, Koeppe RA, Sherman PS, Quesada CA, Raffel DM. 4-[18F]Fluoro-m-hydroxyphenethylguanidine: a radiopharmaceutical for quantifying regional cardiac sympathetic nerve density with positron emission tomography. J Med Chem 2013; 56:7312-23. [PMID: 23965035 PMCID: PMC4520396 DOI: 10.1021/jm400770g] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
4-[(18)F]Fluoro-m-hydroxyphenethylguanidine ([(18)F]4F-MHPG, [(18)F]1) is a new cardiac sympathetic nerve radiotracer with kinetic properties favorable for quantifying regional nerve density with PET and tracer kinetic analysis. An automated synthesis of [(18)F]1 was developed in which the intermediate 4-[(18)F]fluoro-m-tyramine ([(18)F]16) was prepared using a diaryliodonium salt precursor for nucleophilic aromatic [(18)F]fluorination. In PET imaging studies in rhesus macaque monkeys, [(18)F]1 demonstrated high quality cardiac images with low uptake in lungs and the liver. Compartmental modeling of [(18)F]1 kinetics provided net uptake rate constants Ki (mL/min/g wet), and Patlak graphical analysis of [(18)F]1 kinetics provided Patlak slopes Kp (mL/min/g). In pharmacological blocking studies with the norepinephrine transporter inhibitor desipramine (DMI), each of these quantitative measures declined in a dose-dependent manner with increasing DMI doses. These initial results strongly suggest that [(18)F]1 can provide quantitative measures of regional cardiac sympathetic nerve density in human hearts using PET.
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Affiliation(s)
- Keun Sam Jang
- Division of Nuclear Medicine, Department of Radiology, 2276 Medical Sciences I Building, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Yong-Woon Jung
- Division of Nuclear Medicine, Department of Radiology, 2276 Medical Sciences I Building, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Guie Gu
- Division of Nuclear Medicine, Department of Radiology, 2276 Medical Sciences I Building, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Robert A. Koeppe
- Division of Nuclear Medicine, Department of Radiology, 2276 Medical Sciences I Building, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Phillip S. Sherman
- Division of Nuclear Medicine, Department of Radiology, 2276 Medical Sciences I Building, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Carole A. Quesada
- Division of Nuclear Medicine, Department of Radiology, 2276 Medical Sciences I Building, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - David M. Raffel
- Division of Nuclear Medicine, Department of Radiology, 2276 Medical Sciences I Building, University of Michigan Medical School, Ann Arbor, Michigan 48109
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18
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Pop-Busui R, Stevens MJ, Raffel DM, White EA, Mehta M, Plunkett CD, Brown MB, Feldman EL. Effects of triple antioxidant therapy on measures of cardiovascular autonomic neuropathy and on myocardial blood flow in type 1 diabetes: a randomised controlled trial. Diabetologia 2013; 56:1835-44. [PMID: 23740194 PMCID: PMC3730828 DOI: 10.1007/s00125-013-2942-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 05/02/2013] [Indexed: 12/16/2022]
Abstract
AIMS/HYPOTHESIS We evaluated the effects of a combination triple antioxidant therapy on measures of cardiovascular autonomic neuropathy (CAN) and myocardial blood flow (MBF) in patients with type 1 diabetes. METHODS This was a randomised, parallel, placebo-controlled trial. Participants were allocated to interventions by sequentially numbered, opaque, sealed envelopes provided to the research pharmacist. All participants and examiners were masked to treatment allocation. Participants were evaluated by cardiovascular autonomic reflex testing, positron emission tomography with [(11)C]meta-hydroxyephedrine ([(11)C]HED) and [(13)N]ammonia, and adenosine stress testing. Markers of oxidative stress included 24 h urinary F2-isoprostanes. Diabetic peripheral neuropathy (DPN) was evaluated by symptoms, signs, electrophysiology and intra-epidermal nerve fibre density. Randomised participants included 44 eligible adults with type 1 diabetes and mild-to-moderate CAN, who were aged 46 ± 11 years and had HbA1c 58 ± 5 mmol/mol (7.5 ± 1.0%), with no evidence of ischaemic heart disease. Participants underwent a 24-month intervention, consisting of antioxidant treatment with allopurinol, α-lipoic acid and nicotinamide, or placebo. The main outcome was change in the global [(11)C]HED retention index (RI) at 24 months in participants on the active drug compared with those on placebo. RESULTS We analysed data from 44 participants (22 per group). After adjusting for age, sex and in-trial HbA1c, the antioxidant regimen was associated with a slight, but significant worsening of the global [(11)C]HED left ventricle RI (-0.010 [95% CI -0.020, -0.001] p = 0.045) compared with placebo. There were no significant differences at follow-up between antioxidant treatment and placebo in the global MBF, coronary flow reserve, or in measures of DPN and markers of oxidative stress. The majority of adverse events were of mild-to-moderate severity and did not differ between groups CONCLUSIONS/INTERPRETATION In this cohort of type 1 diabetes patients with mild-to-moderate CAN, a combination antioxidant treatment regimen did not prevent progression of CAN, had no beneficial effects on myocardial perfusion or DPN, and may have been detrimental. However, a larger study is necessary to assess the underlying causes of these findings.
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Affiliation(s)
- R Pop-Busui
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA.
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19
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Raffel DM, Koeppe RA, Jung YW, Gu G, Jang KS, Sherman PS, Quesada CA. Quantification of cardiac sympathetic nerve density with N-11C-guanyl-meta-octopamine and tracer kinetic analysis. J Nucl Med 2013; 54:1645-52. [PMID: 23886728 DOI: 10.2967/jnumed.113.120659] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
UNLABELLED Most cardiac sympathetic nerve radiotracers are substrates of the norepinephrine transporter (NET). Existing tracers such as (123)I-metaiodobenzylguanidine ((123)I-MIBG) and (11)C-(-)-meta-hydroxyephedrine ((11)C-HED) are flow-limited tracers because of their rapid NET transport rates. This prevents successful application of kinetic analysis techniques and causes semiquantitative measures of tracer retention to be insensitive to mild-to-moderate nerve losses. N-(11)C-guanyl-(-)-meta-octopamine ((11)C-GMO) has a much slower NET transport rate and is trapped in storage vesicles. The goal of this study was to determine whether analyses of (11)C-GMO kinetics could provide robust and sensitive measures of regional cardiac sympathetic nerve densities. METHODS PET studies were performed in a rhesus macaque monkey under control conditions or after intravenous infusion of the NET inhibitor desipramine (DMI). Five desipramine dose levels were used to establish a range of available cardiac NET levels. Compartmental modeling of (11)C-GMO kinetics yielded estimates of the rate constants K1 (mL/min/g), k2 (min(-1)), and k3 (min(-1)). These values were used to calculate a net uptake rate constant K(i) (mL/min/g) = (K1k3)/(k2 + k3). In addition, Patlak graphical analyses of (11)C-GMO kinetics yielded Patlak slopes K(p) (mL/min/g), which represent alternative measurements of the net uptake rate constant K(i). (11)C-GMO kinetics in isolated rat hearts were also measured for comparison with other tracers. RESULTS In isolated rat hearts, the neuronal uptake rate of (11)C-GMO was 8 times slower than (11)C-HED and 12 times slower than (11)C-MIBG. (11)C-GMO also had a long neuronal retention time (>200 h). Compartmental modeling of (11)C-GMO kinetics in the monkey heart proved stable under all conditions. Calculated net uptake rate constants K(i) tracked desipramine-induced reductions of available NET in a dose-dependent manner, with a half maximal inhibitory concentration (IC50) of 0.087 ± 0.012 mg of desipramine per kilogram. Patlak analysis provided highly linear Patlak plots, and the Patlak slopes Kp also declined in a dose-dependent manner (IC50 = 0.068 ± 0.010 mg of desipramine per kilogram). CONCLUSION Compartmental modeling and Patlak analysis of (11)C-GMO kinetics each provided quantitative parameters that accurately tracked changes in cardiac NET levels. These results strongly suggest that PET studies with (11)C-GMO can provide robust and sensitive quantitative measures of regional cardiac sympathetic nerve densities in human hearts.
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Affiliation(s)
- David M Raffel
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School, Ann Arbor, Michigan, USA.
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Jang KS, Jung YW, Sherman PS, Quesada CA, Gu G, Raffel DM. Synthesis and bioevaluation of [(18)F]4-fluoro-m-hydroxyphenethylguanidine ([(18)F]4F-MHPG): a novel radiotracer for quantitative PET studies of cardiac sympathetic innervation. Bioorg Med Chem Lett 2013; 23:1612-6. [PMID: 23416009 DOI: 10.1016/j.bmcl.2013.01.106] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 01/17/2013] [Accepted: 01/22/2013] [Indexed: 11/28/2022]
Abstract
A new cardiac sympathetic nerve imaging agent, [(18)F]4-fluoro-m-hydroxyphenethylguanidine ([(18)F]4F-MHPG), was synthesized and evaluated. The radiosynthetic intermediate [(18)F]4-fluoro-m-tyramine ([(18)F]4F-MTA) was prepared and then sequentially reacted with cyanogen bromide and NH4Br/NH4OH to afford [(18)F]4F-MHPG. Initial bioevaluations of [(18)F]4F-MHPG (biodistribution studies in rats and kinetic studies in the isolated rat heart) were similar to results previously reported for the carbon-11 labeled analog [(11)C]4F-MHPG. The neuronal uptake rate of [(18)F]4F-MHPG into the isolated rat heart was 0.68ml/min/g wet and its retention time in sympathetic neurons was very long (T1/2 >13h). A PET imaging study in a nonhuman primate with [(18)F]4F-MHPG provided high quality images of the heart, with heart-to-blood ratios at 80-90min after injection of 5-to-1. These initial kinetic and imaging studies of [(18)F]4F-MHPG suggest that this radiotracer may allow for more accurate quantification of regional cardiac sympathetic nerve density than is currently possible with existing neuronal imaging agents.
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Affiliation(s)
- Keun Sam Jang
- Division of Nuclear Medicine, Department of Radiology, 2276 Medical Science I Building, 1301 Catherine Street, University of Michigan Medical School, Ann Arbor, MI 48109, United States
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Raffel DM, Chen W, Jung YW, Jang KS, Gu G, Cozzi NV. Radiotracers for cardiac sympathetic innervation: transport kinetics and binding affinities for the human norepinephrine transporter. Nucl Med Biol 2013; 40:331-7. [PMID: 23306137 DOI: 10.1016/j.nucmedbio.2012.11.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 11/16/2012] [Accepted: 11/28/2012] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Most radiotracers for imaging of cardiac sympathetic innervation are substrates of the norepinephrine transporter (NET). The goal of this study was to characterize the NET transport kinetics and binding affinities of several sympathetic nerve radiotracers, including [(11)C]-(-)-meta-hydroxyephedrine, [(11)C]-(-)-epinephrine, and a series of [(11)C]-labeled phenethylguanidines under development in our laboratory. For comparison, the NET transport kinetics and binding affinities of some [(3)H]-labeled biogenic amines were also determined. METHODS Transport kinetics studies were performed using rat C6 glioma cells stably transfected with the human norepinephrine transporter (C6-hNET cells). For each radiolabeled NET substrate, saturation transport assays with C6-hNET cells measured the Michaelis-Menten transport constants Km and Vmax for NET transport. Competitive inhibition binding assays with homogenized C6-hNET cells and [(3)H]mazindol provided estimates of binding affinities (KI) for NET. RESULTS Km, Vmax and KI values were determined for each NET substrate with a high degree of reproducibility. Interestingly, C6-hNET transport rates for 'tracer concentrations' of substrate, given by the ratio Vmax/Km, were found to be highly correlated with neuronal transport rates measured previously in isolated rat hearts (r(2)=0.96). This suggests that the transport constants Km and Vmax measured using the C6-hNET cells accurately reflect in vivo transport kinetics. CONCLUSION The results of these studies show how structural changes in NET substrates influence NET binding and transport constants, providing valuable insights that can be used in the design of new tracers with more optimal kinetics for quantifying regional sympathetic nerve density.
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Affiliation(s)
- David M Raffel
- Division of Nuclear Medicine, Department of Radiology, 2276 Medical Sciences I Building, University of Michigan Medical School, 1301 Catherine Street, SPC 5610, Ann Arbor, MI 48109, USA.
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Wong KK, Raffel DM, Koeppe RA, Frey KA, Bohnen NI, Gilman S. Pattern of cardiac sympathetic denervation in idiopathic Parkinson disease studied with 11C hydroxyephedrine PET. Radiology 2012; 265:240-7. [PMID: 22843766 DOI: 10.1148/radiol.12112723] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To determine whether cardiac sympathetic denervation in idiopathic Parkinson disease (IPD) affects the left ventricle in a distinct regional pattern versus a more global pattern with use of carbon 11 (11C) meta-hydroxyephedrine (HED) positron emission tomography (PET). MATERIALS AND METHODS This prospective study was approved by the institutional review board and was compliant with HIPAA. Informed consent was obtained from all subjects. Cardiac PET was performed with 11C HED in 27 patients with IPD (20 men and seven women aged 50-74 years; mean age, 62 years±6 [standard deviation]). 11C HED retention indexes (RIs), which reflect nerve density and integrity, were determined. RIs for 33 healthy control subjects (15 men and 18 women aged 20-78 years; mean age, 47 years±17) were used as a control database. Patients with IPD were compared with control subjects by using z score analysis. Global and segmental measurements of sympathetic denervation were expressed as percentage extent, z score severity, and severity-extent product (SEP). Group comparisons were performed with the Student t test. RESULTS The mean 11C HED RI was 0.086 mL of blood per minute per milliliter tissue±0.015 for control subjects and 0.043 mL of blood per minute per milliliter tissue±0.016 for patients with IPD (P<0001). When compared with normative data from the control database, profound cardiac denervation (global extent>50%) was seen in most patients (19 of 27 patients, 70%). Four patients had normal 11C HED studies and four had mild denervation (global extent<25%). The mean global denervation extent was 62%±38, the mean severity z score was -2.7±1.2, and the mean SEP was -202±131 (range, -358 to 0). Segmental analysis revealed relative sparing of anterior and proximal septal segments (mean extent, 48%-51%; mean severity z score, -2.47 to -2.0; mean SEP, -167 to -139), with lateral and proximal inferior segments more severely affected (mean extent, 68%-73%; mean severity z score, -2.8 to -2.62; mean SEP, -271 to -230). Patients with normal findings or preserved denervation did not significantly differ in mean age (t=1.09) or disease duration (t=0.44) compared to patients with severe sympathetic denervation. CONCLUSION Cardiac sympathetic denervation in IPD is extensive, with a segmental pattern that involves the proximal lateral left ventricular wall most severely, with relative sparing of the anterior and proximal septal walls.
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Affiliation(s)
- Ka Kit Wong
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical Center, University of Michigan, 1500 E Medical Center Dr, B1G505G, Ann Arbor, MI 48105, USA.
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Affiliation(s)
- David M Raffel
- Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109, USA.
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Raffel DM, Jung YW, Gildersleeve DL, Sherman PS, Moskwa JJ, Tluczek LJ, Chen W. Radiolabeled phenethylguanidines: novel imaging agents for cardiac sympathetic neurons and adrenergic tumors. J Med Chem 2007; 50:2078-88. [PMID: 17419605 PMCID: PMC2625310 DOI: 10.1021/jm061398y] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The norepinephrine transporter (NET) substrates [123I]-m-iodobenzylguanidine (MIBG) and [11C]-m-hydroxyephedrine (HED) are used as markers of cardiac sympathetic neurons and adrenergic tumors (pheochromocytoma, neuroblastoma). However, their rapid NET transport rates limit their ability to provide accurate measurements of cardiac nerve density. [11C]Phenethylguanidine ([11C]1a) and 12 analogues ([11C]1b-m) were synthesized and evaluated as radiotracers with improved kinetics for quantifying cardiac nerve density. In isolated rat hearts, neuronal uptake rates of [11C]1a-m ranged from 0.24 to 1.96 mL min-1 (g wet wt)-1, and six compounds had extremely long neuronal retention times (clearance T1/2 > 20 h) due to efficient vesicular storage. Positron emission tomography (PET) studies in nonhuman primates with [11C]1e, N-[11C]guanyl-m-octopamine, which has a slow NET transport rate, showed improved myocardial kinetics compared to HED. Compound [11C]1c, [11C]-p-hydroxyphenethylguanidine, which has a rapid NET transport rate, avidly accumulated into rat pheochromocytoma xenograft tumors in mice. These encouraging findings demonstrate that radiolabeled phenethylguanidines deserve further investigation as radiotracers of cardiac sympathetic innervation and adrenergic tumors.
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Affiliation(s)
- David M Raffel
- Division of Nuclear Medicine, Department of Radiology, 3480 Kresge III Building, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA.
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Raffel DM, Koeppe RA, Little R, Wang CN, Liu S, Junck L, Heumann M, Gilman S. PET measurement of cardiac and nigrostriatal denervation in Parkinsonian syndromes. J Nucl Med 2006; 47:1769-77. [PMID: 17079809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023] Open
Abstract
UNLABELLED Scintigraphic imaging with (123)I-metaiodobenzylguanidine ((123)I-MIBG) has demonstrated extensive losses of cardiac sympathetic neurons in idiopathic Parkinson's disease (IPD). In contrast, normal cardiac innervation has been observed in (123)I-MIBG studies of multiple-system atrophy (MSA) and progressive supranuclear palsy (PSP). Consequently, it has been hypothesized that cardiac denervation can be used to differentiate IPD from MSA and PSP. We sought to test this hypothesis by mapping the distribution of cardiac sympathetic neurons in patients with IPD, MSA, and PSP by using PET and (11)C-meta-hydroxyephedrine ((11)C-HED). Also, the relationship between cardiac denervation and nigrostriatal denervation was investigated by measuring striatal presynaptic monoaminergic nerve density with PET and (11)C-dihydrotetrabenazine ((11)C-DTBZ). METHODS (11)C-HED and (11)C-DTBZ scans were obtained for patients with IPD (n = 9), MSA (n = 10), and PSP (n = 8) and for age-matched control subjects (n = 10). Global and regional measurements of (11)C-HED retention were obtained to assess the extent of cardiac sympathetic denervation. (11)C-DTBZ binding was measured in the caudate nucleus, anterior putamen, and posterior putamen. RESULTS As expected, extensive cardiac denervation was observed in several of the patients with IPD. However, substantial cardiac denervation was also seen in some patients with MSA and PSP. (11)C-DTBZ studies demonstrated striatal denervation in all patients with IPD and in most patients with MSA and PSP. No correlation was found between cardiac (11)C-HED retention and striatal (11)C-DTBZ binding. CONCLUSION Cardiac sympathetic denervation was found to occur not only in IPD but also in other movement disorders, such as MSA and PSP. This finding implies that scintigraphic detection of cardiac sympathetic denervation cannot be used independently to discriminate IPD from other movement disorders, such as MSA and PSP. Cardiac sympathetic denervation was not correlated with striatal denervation, suggesting that the pathophysiologic processes underlying cardiac denervation and striatal denervation occur independently in patients with parkinsonian syndromes. These findings provide novel information about central and peripheral denervation in patients with neurodegenerative disorders.
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Affiliation(s)
- David M Raffel
- Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA.
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Raffel DM, Chen W, Sherman PS, Gildersleeve DL, Jung YW. Dependence of cardiac 11C-meta-hydroxyephedrine retention on norepinephrine transporter density. J Nucl Med 2006; 47:1490-6. [PMID: 16954558 PMCID: PMC1618973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023] Open
Abstract
UNLABELLED The norepinephrine analog (11)C-meta-hydroxyephedrine (HED) is used with PET to map the regional distribution of cardiac sympathetic neurons. HED is rapidly transported into sympathetic neurons by the norepinephrine transporter (NET) and stored in vesicles. Although much is known about the neuronal mechanisms of HED uptake and retention, there is little information about the functional relationship between HED retention and cardiac sympathetic nerve density. The goal of this study was to characterize the dependence of HED retention on nerve density in rats with graded levels of cardiac denervation induced chemically with the neurotoxin 6-hydroxydopamine (6-OHDA). METHODS Thirty male Sprague-Dawley rats were divided into 6 groups, and each group was administered a different dose of 6-OHDA: 0 (controls), 7, 11, 15, 22, and 100 mg/kg intraperitoneally. One day after 6-OHDA injection, HED (3.7-8.3 MBq) was injected intravenously into each animal and HED concentrations in heart and blood at 30 min after injection were determined. Heart tissues were frozen and later processed by tissue homogenization and differential centrifugation into a membrane preparation for in vitro measurement of cardiac NET density. A saturation binding assay using (3)H-mazindol as the radioligand was used to measure NET density (maximum number of binding sites [B(max)], fmol/mg protein) for each heart. RESULTS In control animals, NET B(max) was 388 +/- 23 fmol/mg protein and HED heart uptake (HU) at 30 min was 2.89% +/- 0.35 %ID/g (%ID/g is percentage injected dose per gram tissue). The highest 6-OHDA dose of 100 mg/kg caused severe cardiac denervation, decreasing both NET B(max) and HED HU to 8% of their control values. Comparing values for all doses of 6-OHDA, HED retention had a strong linear correlation with NET density: HU = 0.0077B(max) -0.028, r(2) = 0.95. CONCLUSION HED retention is linearly dependent on NET density in rat hearts that have been chemically denervated with 6-OHDA, suggesting that HED retention is a good surrogate measure of NET density in the rat heart. This finding is discussed in relation to clinical observations of the dependence of HED retention on cardiac nerve density in human subjects using PET.
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Affiliation(s)
- David M Raffel
- Department of Radiology, Division of Nuclear Medicine, University of Michigan Medical School, Ann Arbor, 48109-0552, USA.
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Pop-Busui R, Kirkwood I, Schmid H, Marinescu V, Schroeder J, Larkin D, Yamada E, Raffel DM, Stevens MJ. Sympathetic dysfunction in type 1 diabetes: association with impaired myocardial blood flow reserve and diastolic dysfunction. J Am Coll Cardiol 2005; 44:2368-74. [PMID: 15607400 DOI: 10.1016/j.jacc.2004.09.033] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2003] [Revised: 07/02/2004] [Accepted: 09/14/2004] [Indexed: 12/15/2022]
Abstract
OBJECTIVES This study was designed to explore the relationships of early diabetic microangiopathy to alterations of cardiac sympathetic tone and myocardial blood flow (MBF) regulation in subjects with stable type 1 diabetes. BACKGROUND In diabetes, augmented cardiac sympathetic tone and abnormal MBF regulation may predispose to myocardial injury and enhanced cardiac risk. METHODS Subject groups comprised healthy controls (C) (n = 10), healthy diabetic subjects (DC) (n = 12), and diabetic subjects with very early diabetic microangiopathy (DMA+) (n = 16). [(11)C]meta-hydroxyephedrine ([(11)C]HED) and positron emission tomography (PET) were used to explore left ventricular (LV) sympathetic integrity and [(13)N]ammonia-PET to assess MBF regulation in response to cold pressor testing (CPT) and adenosine infusion. RESULTS Deficits of LV [(11)C]HED retention were extensive and global in the DMA+ subjects (36 +/- 31% vs. 1 +/- 1% in DC subjects; p < 0.01) despite preserved autonomic reflex tests. On CPT, plasma norepinephrine excursions were two-fold greater than in C and DC subjects (p < 0.05), and basal LV blood flow decreased (-12%, p < 0.05) in DMA+ but not in C or DC subjects (+45% and +51%, respectively). On adenosine infusion, compared with C subjects, MBF reserve decreased by approximately 45% (p < 0.05) in DMA+ subjects. Diastolic dysfunction was detected by two-dimensional echocardiography in 5 of 8 and 0 of 8 consecutively tested DMA+ and DC subjects, respectively. CONCLUSIONS Augmented cardiac sympathetic tone and responsiveness and impaired myocardial perfusion may contribute to myocardial injury in diabetes.
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Affiliation(s)
- Rodica Pop-Busui
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Michigan, 1150 West Medical Center Drive, Ann Arbor, MI 48109-0678, USA
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Raffel DM, Chen W. Binding of [3H]mazindol to cardiac norepinephrine transporters: kinetic and equilibrium studies. Naunyn Schmiedebergs Arch Pharmacol 2004; 370:9-16. [PMID: 15300361 DOI: 10.1007/s00210-004-0949-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Accepted: 05/27/2004] [Indexed: 01/08/2023]
Abstract
The norepinephrine transporter (NET) is the carrier that drives the neuronal norepinephrine uptake mechanism (uptake1) in mammalian hearts. The radioligand [3H]mazindol binds with high affinity to NET. In this study, the kinetics of [3H]mazindol binding to NET were measured using a rat heart membrane preparation. Results from these studies were used to set up saturation binding assays designed to measure cardiac NET densities (Bmax) and competitive inhibition assays designed to measure inhibitor binding affinities (KI) for NET. Saturation binding assays measured NET densities in rat, rabbit, and canine hearts. Assay reproducibility was assessed and the effect of NaCl concentration on [3H]mazindol binding to NET was studied using membranes from rat and canine hearts. Specificity of [3H]mazindol binding to NET was determined in experiments in which the neurotoxin 6-hydroxydopamine (6-OHDA) was used to selectively destroy cardiac sympathetic nerve terminals in rats. Competitive inhibition studies measured KI values for several NET inhibitors and substrates. In kinetic studies using rat heart membranes, [3H]mazindol exhibited a dissociation rate constant koff=0.0123+/-0.0007 min(-1) and an association rate constant kon=0.0249+/-0.0019 nM(-1)min(-1). In saturation binding assays, [3H]mazindol binding was monophasic and saturable in all cases. Increasing the concentration of NaCl in the assay buffer increased binding affinity significantly, while only modestly increasing Bmax. Injections of 6-OHDA in rats decreased measured cardiac NET Bmax values in a dose-dependent manner, verifying that [3H]mazindol binds specifically to NET from sympathetic nerve terminals. Competitive inhibition studies provided NET inhibitor and substrate KI values consistent with previously reported values. These studies demonstrate the high selectivity of [3H]mazindol binding for the norepinephrine transporter in membrane preparations from mammalian hearts.
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Affiliation(s)
- David M Raffel
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School, 3480 Kresge III Building, Ann Arbor 48109-0552, USA.
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Momose M, Reder S, Raffel DM, Watzlowik P, Wester HJ, Nguyen N, Elsinga PH, Bengel FM, Remien J, Schwaiger M. Evaluation of cardiac beta-adrenoreceptors in the isolated perfused rat heart using (S)-11C-CGP12388. J Nucl Med 2004; 45:471-7. [PMID: 15001690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023] Open
Abstract
UNLABELLED (S)-(11)C-CGP12388 ((11)C-CGP12388) was recently developed as an in vivo PET tracer for the evaluation of cardiac beta-adrenergic receptors. The purpose of this study was to evaluate the myocardial kinetics of (11)C-CGP12388 using the perfused rat heart model. METHODS Normal rat hearts were cannulated for retrograde perfusion according to the Langendorff method. Studies were performed using constant coronary flow rates of 12 mL/min (high flow: n = 6) and 6 mL/min (low flow: n = 6). Beta-adrenergic-blocking studies were also done using propranolol (blocking: n = 6). Two bolus injections of (11)C-CGP12388 were administered at a 25-min interval, and time-activity curves were measured using bismuth germanate detectors. The beta-adrenergic receptor density (B(max)) and total distribution volume (DV(tot)) were estimated using compartmental modeling. After the experiment, B(max) in vitro was measured for all hearts using (3)H-CGP12177, and the values were compared with the B(max) estimated in isolated hearts. RESULTS DV(tot) was significantly lower in the blocking group than in the high-flow group (P < 0.01), and there was no significant difference in DV(tot) between the high- and the low-flow groups. B(max) values estimated from (11)C-CGP12388 kinetics were 5.05 +/- 0.90 pmol/g under the high-flow model and 5.20 +/- 0.63 pmol/g under the low-flow model. The B(max) results in isolated hearts correlated significantly with the measured in vitro B(max) values (r(2) = 0.69; P < 0.001). CONCLUSION Beta-adrenoreceptor density in the isolated rat heart can be quantified using (11)C-CGP12388 and a 2-injection protocol. The binding of the tracer was flow independent, with low nonspecific binding. These results suggest that (11)C-CGP12388 is a promising PET tracer that may be applicable to human studies.
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Affiliation(s)
- Mitsuru Momose
- Nuklearmedizinische Klinik und Poliklinik der Technischen Universität München, Munich, Germany
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Abstract
The ability to study multiple physiologic processes of the brain simultaneously within the same subject would provide a new means to explore the interactions between neurotransmitter systems in vivo. Currently, examination of two distinct neuropharmacologic measures with positron emission tomography (PET) necessitates performing two separate scans spaced in time to allow for radionuclide decay. The authors present results from a dual-tracer PET study protocol using a single dynamic-scan acquisition where the injections of two tracers are offset by several minutes. Kinetic analysis is used to estimate neuropharmacologic parameters for both tracers simultaneously using a combined compartmental model configuration. This approach results in a large reduction in total study time of nearly 2 hours for carbon-11-labeled tracers. As multiple neuropharmacologic measures are obtained at nearly the same time, interventional protocols involving a pair of dual-tracer scans become feasible in a single PET session. Both computer simulations and actual human PET studies were performed using combinations of three different tracers: [11C]flumazenil, N-[11C]methylpiperidinyl propionate, and [ 11 C]dihydrotetrabenazine. Computer simulations of tracer-injection separations of 10 to 30 minutes showed the feasibility of the approach for separations down to 15 to 20 minutes or less. Dual-tracer PET studies were performed in 32 healthy volunteers using injection separations of 10, 15, or 20 minutes. Model parameter estimates for each tracer were similar to those obtained from previously performed single-injection studies. Voxel-by-voxel parametric images were of good quality for injections spaced by 20 minutes and were nearly as good for 15-minute separations, but were degraded noticeably for some model parameters when injections were spaced by only 10 minutes. The authors conclude that dual-tracer single-scan PET is feasible, yields accurate estimates of multiple neuropharmacologic measures, and can be implemented with a number of different radiotracer pairs.
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Affiliation(s)
- R A Koeppe
- Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109, USA
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Abstract
The autonomic nervous system plays a critical role in the regulation of cardiac function. Abnormalities of cardiac innervation have been implicated in the pathophysiology of many heart diseases, including sudden cardiac death and congestive heart failure. In an effort to provide clinicians with the ability to regionally map cardiac innervation, several radiotracers for imaging cardiac sympathetic neurons have been developed. This paper reviews the development of neuronal imaging agents and discusses their emerging role in the noninvasive assessment of cardiac sympathetic innervation.
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Affiliation(s)
- D M Raffel
- Division of Nuclear Medicine, Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, MI 48109-0552, USA.
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Abstract
The introduction of tracer kinetic modeling techniques in conjunction with nuclear imaging has allowed the assessment of physiologic processes in the myocardium in a noninvasive and quantitative manner. Alongside the development of novel radiopharmaceuticals for both positron emission tomography and single photon emission computed tomography is the clarification of their pharmacology, pharmacokinetics, and modeling strategies for assessment of physiologic rates from imaging data. Image analysis and tracer kinetic modeling techniques used in nuclear cardiology must address unique considerations related to the heart. The most commonly used tracers and modeling techniques are presently discussed, with particular attention given to methods that allow absolute quantitation of physiologic processes. The applications of these techniques are obvious in research protocols and may find more use in future clinical studies.
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Affiliation(s)
- T R DeGrado
- Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA.
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Raffel DM, Corbett JR, del Rosario RB, Mukhopadhyay SK, Gildersleeve DL, Rose P, Wieland DM. Sensitivity of [11C]phenylephrine kinetics to monoamine oxidase activity in normal human heart. J Nucl Med 1999; 40:232-8. [PMID: 10025828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
UNLABELLED Phenylephrine labeled with 11C was developed as a radiotracer for imaging studies of cardiac sympathetic nerves with PET. A structural analog of norepinephrine, (-)-[11C]phenylephrine (PHEN) is transported into cardiac sympathetic nerve varicosities by the neuronal norepinephrine transporter and stored in vesicles. PHEN is also a substrate for monoamine oxidase (MAO). The goal of this study was to assess the importance of neuronal MAO activity on the kinetics of PHEN in the normal human heart. MAO metabolism of PHEN was inhibited at the tracer level by substituting deuterium atoms for the two hydrogen atoms at the alpha-carbon side chain position to yield the MAO-resistant analog D2-PHEN. METHODS Paired PET studies of PHEN and D2-PHEN were performed in six normal volunteers. Hemodynamic and electrocardiographic responses were monitored. Blood levels of intact radiotracer and radiolabeled metabolites were measured in venous samples taken during the 60 min dynamic PET study. Myocardial retention of the tracers was regionally quantified as a retention index. Tracer efflux between 6 and 50 min after tracer injection was fit to a single exponential process to obtain a washout half-time for all left ventricular regions. RESULTS Although initial heart uptake of the two tracers was similar, D2-PHEN cleared from the heart 2.6 times more slowly than PHEN (mean half-time 155+/-52 versus 55+/-10 min, respectively; P < 0.01). Correspondingly, heart retention of D2-PHEN at 40-60 min after tracer injection was higher than PHEN (mean retention indices 0.086+/-0.018 versus 0.066+/-0.011 mL blood/ min/mL tissue, respectively; P < 0.003). CONCLUSION Efflux of radioactivity from normal human heart after uptake of PHEN is primarily due to metabolism of the tracer by neuronal MAO. Related mechanistic studies in the isolated rat heart indicate that vesicular storage of PHEN protects the tracer from rapid metabolism by neuronal MAO, suggesting that MAO metabolism of PHEN leaking from storage vesicles leads to the gradual loss of PHEN from the neurons. Thus, although MAO metabolism influences the rate of clearance of PHEN from the neurons, MAO metabolism is not the rate-determining step in the observed efflux rate under normal conditions. Rather, the rate at which PHEN leaks from storage vesicles is likely to be the rate-limiting step in the observed efflux rate.
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Affiliation(s)
- D M Raffel
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor 48109-0552, USA
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Raffel DM, Wieland DM. Influence of vesicular storage and monoamine oxidase activity on [11C]phenylephrine kinetics: studies in isolated rat heart. J Nucl Med 1999; 40:323-30. [PMID: 10025842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
UNLABELLED [11C]Phenylephrine (PHEN) is a radiolabeled analogue of norepinephrine that is transported into cardiac sympathetic nerve varicosities by the neuronal norepinephrine transporter and taken up into storage vesicles localized within the nerve varicosities by the vesicular monoamine transporter. PHEN is structurally related to two previously developed sympathetic nerve markers: [11C]-meta-hydroxyephedrine and [11C]epinephrine. To better characterize the neuronal handling of PHEN, particularly its sensitivity to neuronal monoamine oxidase (MAO) activity, kinetic studies in an isolated working rat heart system were performed. METHODS Radiotracer was administered to the isolated working heart as a 10-min constant infusion followed by a 110-min washout period. Two distinctly different approaches were used to assess the sensitivity of the kinetics of PHEN to MAO activity. In the first approach, oxidation of PHEN by MAO was inhibited at the enzymatic level with the MAO inhibitor pargyline. In the second approach, the two hydrogen atoms on the a-carbon of the side chain of PHEN were replaced with deuterium atoms ([11C](-)-alpha-alpha-dideutero-phenylephrine [D2-PHEN]) to inhibit MAO activity at the tracer level. The importance of vesicular uptake on the kinetics of PHEN and D2-PHEN was assessed by inhibiting vesicular monoamine transporter-mediated storage into vesicles with reserpine. RESULTS Under control conditions, PHEN initially accumulated into the heart at a rate of 0.72+/-0.15 mL/min/g wet. Inhibition of MAO activity with either pargyline or di-deuterium substitution did not significantly alter this rate. However, MAO inhibition did significantly slow the clearance of radioactivity from the heart during the washout phase of the study. Blocking vesicular uptake with reserpine reduced the initial uptake rates of PHEN and D2-PHEN, as well as greatly accelerated the clearance of radioactivity from the heart during washout. CONCLUSION These studies indicate that PHEN kinetics are sensitive to neuronal MAO activity. Under normal conditions, efficient vesicular storage of PHEN serves to protect the tracer from rapid metabolism by neuronal MAO. However, it is likely that leakage of PHEN from the storage vesicles and subsequent metabolism by MAO lead to an appreciable clearance of radioactivity from the heart.
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Affiliation(s)
- D M Raffel
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor 48109-0552, USA
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Stevens MJ, Raffel DM, Allman KC, Schwaiger M, Wieland DM. Regression and progression of cardiac sympathetic dysinnervation complicating diabetes: an assessment by C-11 hydroxyephedrine and positron emission tomography. Metabolism 1999; 48:92-101. [PMID: 9920151 DOI: 10.1016/s0026-0495(99)90016-1] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cardiovascular denervation complicating diabetes has been implicated in sudden cardiac death potentially by altering myocardial electrical stability and impairing myocardial blood flow. Scintigraphic evaluation of cardiac sympathetic integrity has frequently demonstrated deficits in distal left ventricular (LV) sympathetic innervation in asymptomatic diabetic subjects without abnormalities on cardiovascular reflex testing. However, the clinical significance and subsequent fate of these small regional defects is unknown. This study reports the results of a prospective observational study in which positron emission tomography (PET) with (-)-[11C]-meta-hydroxyephedrine ([11C]-HED) was used to evaluate the effects of glycemic control on the progression of small regional LV [11C]-HED retention deficits in 11 insulin-dependent diabetic subjects over a period of 3 years. The subjects were divided into two groups based on attained glycemic control during this period: group A contained six subjects with good glycemic control (individual mean HbA1c <8%), and group B contained five subjects with poor glycemic control (individual mean HbAlc > or =8%). Changes in regional [11C]-HED retention were compared with reference values obtained from 10 healthy aged-matched nondiabetic subjects. At baseline, abnormalities of [11C]-HED retention affected 7.3%+/-1.4% and 9.9%+/-6.6% of the LV in group A and B subjects, respectively, with maximal deficits of LV [ C]-HED retention involving the distal myocardial segments. At the final assessment in group A, the extent of the deficits in [11C]-HED retention decreased to involve only 1.7%+/-0.7% of LV (P<.05 v. baseline scan), with significant increases in [11C]-HED retention occurring in both the distal and proximal myocardial segments. In contrast, in group B with poor glycemic control, the extent of [11C]-HED deficits increased to involve 34%+/-3.5% of the LV (P<.01 v. baseline), with retention of [11C]-HED significantly decreasing in the distal segments ([11C]-HED retention index, 0.066+/-0.003 v. 0.057+/-0.002, P<.05, at baseline and final assessment, respectively). Poor glycemic control was associated with increased heterogeneity of LV [11C]-HED retention, since three of five group B subjects developed abnormally increased [11C]-HED retention in the proximal myocardial segments. In conclusion, defects in LV sympathetic innervation can regress or progress in diabetic subjects achieving good or poor glycemic control, respectively. In diabetic subjects with early cardiovascular denervation, institution of good glycemic control may prevent the development of myocardial sympathetic dysinnervation and enhanced cardiac risk.
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Affiliation(s)
- M J Stevens
- Department of Internal Medicine, University of Michigan, Ann Arbor 48109-0678, USA
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Stevens MJ, Raffel DM, Allman KC, Dayanikli F, Ficaro E, Sandford T, Wieland DM, Pfeifer MA, Schwaiger M. Cardiac sympathetic dysinnervation in diabetes: implications for enhanced cardiovascular risk. Circulation 1998; 98:961-8. [PMID: 9737515 DOI: 10.1161/01.cir.98.10.961] [Citation(s) in RCA: 138] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Regional cardiac sympathetic hyperactivity predisposes to malignant arrhythmias in nondiabetic cardiac disease. Conversely, however, cardiac sympathetic denervation predicts increased morbidity and mortality in severe diabetic autonomic neuropathy (DAN). To unite these divergent observations, we propose that in diabetes regional cardiac denervation may elsewhere induce regional sympathetic hyperactivity, which may in turn act as a focus for chemical and electrical instability. Therefore, the aim of this study was to explore regional changes in sympathetic neuronal density and tone in diabetic patients with and without DAN. METHODS AND RESULTS PET using the sympathetic neurotransmitter analogue 11C-labeled hydroxyephedrine ([11C]-HED) was used to characterize left ventricular sympathetic innervation in diabetic patients by assessing regional disturbances in myocardial tracer retention and washout. The subject groups comprised 10 diabetic subjects without DAN, 10 diabetic subjects with mild DAN, 9 diabetic subjects with severe DAN, and 10 healthy subjects. Abnormalities of cardiac [11C]-HED retention were detected in 40% of DAN-free diabetic subjects. In subjects with mild neuropathy, tracer defects were observed only in the distal inferior wall of the left ventricle, whereas with more severe neuropathy, defects extended to involve the distal and proximal anterolateral and inferior walls. Absolute [11C]-HED retention was found to be increased by 33% (P<0.01) in the proximal segments of the severe DAN subjects compared with the same regions in the DAN-free subjects (30%; P<0.01 greater than the proximal segments of the mild DAN subjects). Despite the increased tracer retention, no appreciable washout of tracer was observed in the proximal segments, consistent with normal regional tone but increased sympathetic innervation. Distally, [11C]-HED retention was decreased in severe DAN by 33% (P<0.01) compared with the DAN-free diabetic subjects (21%; P<0.05 lower than the distal segments of the mild DAN subjects). CONCLUSIONS Diabetes may result in left ventricular sympathetic dysinnervation with proximal hyperinnervation complicating distal denervation. This combination could result in potentially life-threatening myocardial electrical instability and explain the enhanced cardioprotection from beta-blockade in these subjects.
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Affiliation(s)
- M J Stevens
- Department of Internal Medicine, University of Michigan, Ann Arbor 48109-0678, USA.
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Stevens MJ, Dayanikli F, Raffel DM, Allman KC, Sandford T, Feldman EL, Wieland DM, Corbett J, Schwaiger M. Scintigraphic assessment of regionalized defects in myocardial sympathetic innervation and blood flow regulation in diabetic patients with autonomic neuropathy. J Am Coll Cardiol 1998; 31:1575-84. [PMID: 9626837 DOI: 10.1016/s0735-1097(98)00128-4] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVES This study sought to evaluate whether regional sympathetic myocardial denervation in diabetes is associated with abnormal myocardial blood flow under rest and adenosine-stimulated conditions. BACKGROUND Diabetic autonomic neuropathy (DAN) has been invoked as a cause of unexplained sudden cardiac death, potentially by altering electrical stability or impairing myocardial blood flow, or both. The effects of denervation on cardiac blood flow in diabetes are unknown. METHODS We studied 14 diabetic subjects (7 without DAN, 7 with advanced DAN) and 13 nondiabetic control subjects without known coronary artery disease. Positron emission tomography using carbon-11 hydroxyephedrine was used to characterize left ventricular cardiac sympathetic innervation and nitrogen-13 ammonia to measure myocardial blood flow at rest and after intravenous administration of adenosine (140 microg/kg body weight per min). RESULTS Persistent sympathetic left ventricular proximal wall innervation was observed, even in advanced neuropathy. Rest myocardial blood flow was higher in the neuropathic subjects (109 +/- 29 ml/100 g per min) than in either the nondiabetic (69 +/- 8 ml/100 g per min, p < 0.01) or the nonneuropathic diabetic subjects (79 +/- 23 ml/100 g per min, p < 0.05). During adenosine infusion, global left ventricular myocardial blood flow was significantly less in the neuropathic subjects (204 +/- 73 ml/100 g per min) than in the nonneuropathic diabetic group (324 +/- 135 ml/100 g per min, p < 0.05). Coronary flow reserve was also decreased in the neuropathic subjects, who achieved only 46% (p < 0.01) and 44% (p < 0.01) of the values measured in nondiabetic and nonneuropathic diabetic subjects, respectively. Assessment of the myocardial innervation/blood flow relation during adenosine infusion showed that myocardial blood flow in neuropathic subjects was virtually identical to that in nonneuropathic diabetic subjects in the distal denervated myocardium but was 43% (p < 0.05) lower than that in the nonneuropathic diabetic subjects in the proximal innervated segments. CONCLUSIONS DAN is associated with altered myocardial blood flow, with regions of persistent sympathetic innervation exhibiting the greatest deficits of vasodilator reserve. Future studies are required to evaluate the etiology of these abnormalities and to evaluate the contribution of the persistent islands of innervation to sudden cardiac death complicating diabetes.
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Affiliation(s)
- M J Stevens
- Department of Internal Medicine, University of Michigan, Ann Arbor, USA.
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Donnelly JP, Raffel DM, Shulkin BL, Corbett JR, Bove EL, Mosca RS, Kulik TJ. Resting coronary flow and coronary flow reserve in human infants after repair or palliation of congenital heart defects as measured by positron emission tomography. J Thorac Cardiovasc Surg 1998; 115:103-10. [PMID: 9451052 DOI: 10.1016/s0022-5223(98)70448-9] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Coronary physiology in infants with congenital heart disease remains unclear. Our objective was to better understand coronary physiology in infants with congenital heart disease. METHODS We used positron emission tomography with nitrogen 13-labeled ammonia to measure myocardial perfusion at rest and with adenosine (142 micrograms/kg/min x 6 minutes) in five infants after anatomic repair of a congenital heart lesion (group I), and in five infants after Norwood palliation for hypoplastic left heart syndrome (group II). The groups were matched for age, weight, and time from the operation. RESULTS Resting coronary flow in the left ventricle in group I was 1.8 +/- 0.2 ml/min/gm; resting flow in the right ventricle in group II was 1.0 +/- 0.3 ml/min/gm (p = 0.003). Coronary flow with adenosine was 2.6 +/- 0.5 ml/min/gm in group I and 1.5 +/- 0.7 ml/min/gm in group II (p = 0.02). Absolute coronary flow reserve was the same in both groups (1.5 +/- 0.2 in group I vs 1.6 +/- 0.3 in group II, p = 0.45). Oxygen delivery was reduced in group II compared with group I at rest (16.1 +/- 4.2 ml/min/100 gm vs 28.9 +/- 4.42 ml/min/100 gm, p = 0.02) and with adenosine (25.5 +/- 8.1 ml/min/100 gm vs 42.3 +/- 5.8 ml/min/100 gm, p = 0.02). CONCLUSIONS Infants with repaired heart disease have higher resting flow and less coronary flow reserve than previously reported for adults. After Norwood palliation, infants have less perfusion and oxygen delivery to the systemic ventricle than do infants with a repaired lesion. This may in part explain why the outcome for patients with Norwood palliation is less favorable than for others.
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Affiliation(s)
- J P Donnelly
- Department of Pediatrics, University of Michigan, Ann Arbor, USA
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Raffel DM, Corbett JR, del Rosario RB, Gildersleeve DL, Chiao PC, Schwaiger M, Wieland DM. Clinical evaluation of carbon-11-phenylephrine: MAO-sensitive marker of cardiac sympathetic neurons. J Nucl Med 1996; 37:1923-31. [PMID: 8970507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
UNLABELLED The sympathomimetic drug phenylephrine recently has been labeled with 11C for use in PET studies of cardiac sympathetic innervation. Previous reports using isolated perfused rat heart models indicate that phenylephrine is metabolized by intraneuronal monoamine oxidase (MAO). This report compares the imaging characteristics, neuronal selectivity and kinetics of (-)-[11C]phenylephrine (PHEN) to the structurally similar but MAO-resistant analog (-)-[11C]-meta-hydroxyephedrine (HED), an established heart neuronal marker. METHODS Fourteen healthy volunteers were studied with PET and PHEN. Ten had paired studies with HED; four of the 10 were scanned a second time with each tracer after oral administration of desipramine, a selective neuronal transport blocker. Hemodynamic and electrocardiographic responses were monitored. Blood levels of intact radiotracer and radiolabeled metabolites were determined from venous blood samples taken during the PET study. Myocardial retention indices for both tracers were calculated. RESULTS No hemodynamic or electrocardiographic effects were observed with either tracer. PHEN showed reduced myocardial retention at 50 min compared to HED; however, image quality and uniformity of distribution were comparable. PHEN cleared from myocardium with a mean half-time of 59 +/- 5 min, while myocardial levels of HED remained constant. PHEN metabolites appeared in the blood approximately three times faster than HED metabolites. Desipramine pretreatment markedly reduced (> 60%) myocardial retention of both PHEN and HED. CONCLUSION PHEN provides PET images of human heart comparable in quality and uniformity to HED. Like HED, PHEN localizes in the sympathetic nerves of the heart. However, the more rapid efflux of PHEN, that is likely mediated by MAO, may provide information on the functional status of cardiac sympathetic neurons unobtainable with HED.
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Affiliation(s)
- D M Raffel
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, USA
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Jung YW, Frey KA, Mulholland GK, del Rosario R, Sherman PS, Raffel DM, Van Dort ME, Kuhl DE, Gildersleeve DL, Wieland DM. Vesamicol receptor mapping of brain cholinergic neurons with radioiodine-labeled positional isomers of benzovesamicol. J Med Chem 1996; 39:3331-42. [PMID: 8765517 DOI: 10.1021/jm9507486] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
UNLABELLED Alzheimer's disease is characterized by progressive cerebral cholinergic neuronal degeneration. Radiotracer analogs of benzovesamicol, which bind with high affinity to the vesamicol receptor located on the uptake transporter of acetylcholine storage vesicles, may provide an in vivo marker of cholinergic neuronal integrity. Five positional isomers of racemic iodobenzovesamicol (4'-, 5-, 6-, 7-, and 8-IBVM) were synthesized, exchange-labeled with iodine-125, and evaluated as possible in vivo markers for central cholinergic neurons. Only two isomers, 5-IBVM (5) and 6-IBVM (10), gave distribution patterns in mouse brain consistent with cholinergic innervation: striatum >> hippocampus > or = cortex > hypothalamus >> cerebellum. The 24-h tissue-to-cerebellum concentration ratios for 5-IBVM (5) were 3-4-fold higher for striatum, cortex, and hippocampus than the respective ratios for 6-IBVM (10). Neither 8-IBVM (16) nor 4'-IBVM (17) exhibited selective retention in any of the brain regions examined. In the heart, only 5-IBVM (5) exhibited an atria-to-ventricles concentration ratio consistent with high peripheral cholinergic neuronal selectivity. The 7-IBVM (14) isomer exhibited an anomalous brain distribution pattern, marked by high and prolonged retention in the five brain regions, most notably the cerebellum. This isomer was screened for binding in a series of 26 different biological assays; 7-IBVM (14) exhibited affinity only for the delta-receptor with an IC50 of approximately 30 nM. Drug-blocking studies suggested that brain retention of 7-IBVM (14) reflects high-affinity binding to both vesamicol and delta-receptors. Competitive binding studies using rat cortical homogenates gave IC50 values for binding to the vesamicol receptor of 2.5 nM for 5-IBVM (5), 4.8 nM for 6-IBVM (10), and 3.5 nM for 7-IBVM (14). Ex vivo autoradiography of rat brain after injection of (-)-5-[125I]IBVM ((-)-[125I]5) clearly delineated small cholinergic-rich areas such as basolateral amygdala, interpeduncular nucleus, and facial nuclei. Except for cortex, regional brain levels of (-)-5-[123I]IBVM ((-)-[123I]5) at 4 h exhibited a linear correlation (r2 = 0.99) with endogenous levels of choline acetyltransferase. CONCLUSION Vesamicol receptor mapping of cholinergic nerve terminals in murine brain can be achieved with 5-IBVM (5) and less robustly with 6-IBVM (10), whereas the brain localization of 7-IBVM (14) reflects high-affinity binding to both vesamicol and delta-receptors.
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Affiliation(s)
- Y W Jung
- Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor 48109-0552, USA
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Affiliation(s)
- D M Raffel
- Nuklearmedizinische Klinik, Technischen Universität München, Germany
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Ng CK, Holden JE, DeGrado TR, Raffel DM, Kornguth ML, Gatley SJ. Sensitivity of myocardial fluorodeoxyglucose lumped constant to glucose and insulin. Am J Physiol 1991; 260:H593-603. [PMID: 1996702 DOI: 10.1152/ajpheart.1991.260.2.h593] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The lumped constant (LC) that relates the steady-state phosphorylation rate of 2-[18F]-fluoro-2-deoxy-D-glucose (2-FDG) to that of glucose was determined in an isolated working rat heart model by direct assay of phosphorylation product formation. Five conditions were tested: 5 and 30 mM glucose without insulin, and 2, 3.5, and 5 mM glucose + 10 mU/ml insulin, all at high external work load. Hearts were continuously perfused with 2-FDG and tritiated glucose without recirculation. The steady-state production of tritiated water was used to monitor the glucose phosphorylation rate. Perfused hearts were freeze-clamped and extracted in perchloric acid, and 2-FDG-6-phosphate was separated from 2-FDG with a formate column. The accumulation of 2-FDG phosphorylation products in tissue was also determined from the slopes of the total tissue radioactivity time courses measured by external gamma-ray detection. Without insulin, the LC value decreased 18% as perfusate glucose concentration was increased sixfold (0.94 +/- 0.06 at 5 mM vs. 0.77 +/- 0.17 at 30 mM). With insulin, the LC rose from 0.33 +/- 0.03 at 5 mM to 1.19 +/- 0.05 at 2 mM glucose concentration. The trends can be interpreted in terms of the concept of control strength; the LC value rises as glycolysis becomes rate limited by transport into cells. This potential variability of the LC must be addressed in the quantitative interpretation of myocardial deoxyglucose studies.
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Affiliation(s)
- C K Ng
- Department of Medical Physics, University of Wisconsin, Madison 53706
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DeGrado TR, Holden JE, Ng CK, Raffel DM, Gatley SJ. Quantitative analysis of myocardial kinetics of 15-p-[iodine-125] iodophenylpentadecanoic acid. J Nucl Med 1989; 30:1211-8. [PMID: 2738702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Myocardial extraction and the characteristic tissue clearance of radioactivity following bolus injections of a radioiodinated (125I) long chain fatty acid (LCFA) analog 15-p-iodophenylpentadecanoic acid (IPPA) were examined in the isolated perfused working rat heart. Radioactivity remaining in the heart was monitored with external scintillation probes. A compartmental model which included nonesterified tracer, catabolite, and complex lipid compartments successfully fitted tissue time-radioactivity residue curves, and gave a value for the rate of IPPA oxidation 1.8 times that obtained from steady-state release of tritiated water from labeled palmitic acid. The technique was sensitive to the impairment of LCFA oxidation in hearts of animals treated with the carnitine palmitoyltransferase I inhibitor, 2[5(4-chlorophenyl)pentyl]oxirane-2-carboxylate (POCA). IPPA or similar modified fatty acids may be better than 11C-labeled physiological fatty acids such as palmitate in this type of study, because efflux of unoxidized tracer and catabolite(s) from the heart are kinetically more distinct, and their contributions to the early data can be reliably separated. This technique may be suitable for extension to in vivo measurements with position tomography and appropriate modified fatty acids.
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Affiliation(s)
- T R DeGrado
- Department of Medical Physics, University of Wisconsin, Madison
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Abstract
A new two-sensor technique for measurement of O2 consumption in isolated organs without venous cannulation was successfully applied to the isolated rat heart. Because this technique eliminates the net exchange of O2 between venous effluent and the environment, measurement of the O2 concentration is conveniently made by use of a polarographic sensor in a collected pool of effluent at the bottom of a closed organ chamber. The method was validated against conventional techniques using cannulation of the pulmonary artery. The two-sensor technique allows O2 consumption measurements to be made in isolated organ preparations in which representative venous cannulation is prohibitively difficult, for example in organs with multiple venous drains, or those in which cannulation would be expected to cause excessive perturbation of physiological status.
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Affiliation(s)
- T R DeGrado
- Department of Medical Physics, University of Wisconsin, Madison 53706
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DeGrado TR, Holden JE, Ng CK, Raffel DM, Gatley SJ. beta-Methyl-15-p-iodophenylpentadecanoic acid metabolism and kinetics in the isolated rat heart. Eur J Nucl Med 1989; 15:78-80. [PMID: 2920741 DOI: 10.1007/bf00702623] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The use of 15-p-iodophenyl-beta-methyl-pentadecanoic acid (beta Me-IPPA) as an indicator of long chain fatty acid (LCFA) utilization in nuclear medicine studies was evaluated in the isolated, perfused, working rat heart. Time courses of radioactivity (residue curves) were obtained following bolus injections of both beta Me-IPPA and its straight chain counterpart 15-p-iodophenyl-pentadecanoic acid (IPPA). IPPA kinetics clearly indicated flow independent impairment of fatty acid oxidation caused by the carnitine palmitoyltransferase I inhibitor 2[5(4-chlorophenyl)pentyl]oxirane-2-carboxylate (POCA). In contrast, beta Me-IPPA kinetics were insensitive to changes in fatty acid oxidation rate and net utilization of long chain fatty acid. Analysis of radiolabeled species in coronary effluent and heart homogenates showed the methylated fatty acid to be readily incorporated into complex lipids but a poor substrate for oxidation. POCA did not significantly alter metabolism of the tracer, suggesting that the tracer is poorly metabolized beyond beta Me-IPPA-CoA in the oxidative pathway.
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Affiliation(s)
- T R DeGrado
- Department of Medical Physics, University of Wisconsin, Madison 53706
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Kornguth ML, Holden JE, Degrado TR, Ng CK, Raffel DM, Gatley SJ. Kinetics of [18F]1-fluoro-2,4-dinitrobenzene, a potential probe for the glutathione detoxification system, in perfused working rat heart. Int J Rad Appl Instrum B 1989; 16:519-24. [PMID: 2807957 DOI: 10.1016/0883-2897(89)90066-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
[18F]1-Fluoro-2,4-dinitrobenzene (FDNB), a substrate for the detoxification enzyme glutathione-S-transferase, was prepared by 18F-Cl exchange. It was administered as a rapid bolus in the perfused working rat heart and the kinetics of the label were followed by external coincidence detection and by analysis of the coronary effluents and tissue homogenates. The data suggest that part of the extracted tracer was released, part was dehalogenated and part was reversibly incorporated into a large tissue pool of FDNB that was not a substrate for defluorination. The rates of the specific processes, estimated from the residue data, may be sensitive to changes in the glutathione detoxification system and therefore applicable to investigation of the compromised myocardium.
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Affiliation(s)
- M L Kornguth
- Department of Medical Physics, University of Wisconsin, Madison 53706
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DeGrado TR, Holden JE, Ng CK, Raffel DM, Gatley SJ. Comparison of 16-iodohexadecanoic acid (IHDA) and 15-p-iodophenylpentadecanoic acid (IPPA) metabolism and kinetics in the isolated rat heart. Eur J Nucl Med 1988; 14:600-6. [PMID: 3243308 DOI: 10.1007/bf00251783] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Time courses of radioactivity (residue curves) were obtained following bolus injection into working rat hearts of two 125I-labeled long chain fatty acids: 16-iodohexadecanoic acid (IHDA) and 15-p-iodophenylpentadecanoic acid (IPPA). Residue curves were analyzed in terms of a rapid vascular washout component, an early tissue clearance component, and a very slow late component. For IHDA and IPPA in control hearts, early myocardial clearance kinetics were rate limited by the diffusion of catabolites. Sensitivity of the kinetics to impaired fatty acid oxidation was examination by pretreatment of animals with 2[5(4-chlorophenyl)pentyl]oxirane-2-carboxylate (POCA). Decreased fatty acid oxidation was indicated in IHDA and IPPA residue curves by a decrease in the relative size of the early clearance component. Analysis of radiolabeled species in coronary effluent and heart homogenates showed that back diffusion of IPPA was slower than that of IHDA; this discrepancy was most apparent in POCA hearts. In vitro binding assays suggested higher tissue:albumin relative affinity for IPPA than for IHDA. Thus, IPPA early clearance kinetics were more closely related to the clearance of labeled catabolite(s) and were therefore more sensitive to the oxidation rate of long chain fatty acids.
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Affiliation(s)
- T R DeGrado
- Department of Medical Physics, University of Wisconsin, Madison 53706
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