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Khalil M, Lau HC, Thackeray JT, Mikail N, Gebhard C, Quyyumi AA, Bengel FM, Bremner JD, Vaccarino V, Tawakol A, Osborne MT. Heart-brain axis: Pushing the boundaries of cardiovascular molecular imaging. J Nucl Cardiol 2024:101870. [PMID: 38685398 DOI: 10.1016/j.nuclcard.2024.101870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Revised: 04/18/2024] [Accepted: 04/22/2024] [Indexed: 05/02/2024]
Abstract
Despite decades of research, the heart-brain axis continues to challenge investigators seeking to unravel its complex pathobiology. Strong epidemiologic evidence supports a link by which insult or injury to one of the organs increases the risk of pathology in the other. The putative pathways have important differences between sexes and include alterations in autonomic function, metabolism, inflammation, and neurohormonal mechanisms that participate in crosstalk between the heart and brain and contribute to vascular changes, the development of shared risk factors, and oxidative stress. Recently, given its unique ability to characterize biological processes in multiple tissues simultaneously, molecular imaging has yielded important insights into the interplay of these organ systems under conditions of stress and disease. Yet, additional research is needed to probe further into the mechanisms underlying the heart-brain axis and to evaluate the impact of targeted interventions.
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Affiliation(s)
- Maria Khalil
- Cardiovascular Imaging Research Center, Massachusetts General Hospital, Boston, MA, USA; Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Hui Chong Lau
- Cardiovascular Imaging Research Center, Massachusetts General Hospital, Boston, MA, USA; Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - James T Thackeray
- Department of Nuclear Medicine, Hannover Medical School, Hannover, Germany
| | - Nidaa Mikail
- Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland; Center for Molecular Cardiology, University Hospital Zurich, Schlieren, Switzerland
| | - Catherine Gebhard
- Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland; Center for Molecular Cardiology, University Hospital Zurich, Schlieren, Switzerland; Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Arshed A Quyyumi
- Department of Medicine (Cardiology), Emory University School of Medicine, Atlanta, GA, USA
| | - Frank M Bengel
- Department of Nuclear Medicine, Hannover Medical School, Hannover, Germany
| | - J Douglas Bremner
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, USA; Atlanta VA Medical Center, Decatur, GA, USA; Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, USA
| | - Viola Vaccarino
- Department of Medicine (Cardiology), Emory University School of Medicine, Atlanta, GA, USA; Department of Epidemiology, Emory University, Atlanta, GA, USA
| | - Ahmed Tawakol
- Cardiovascular Imaging Research Center, Massachusetts General Hospital, Boston, MA, USA; Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Michael T Osborne
- Cardiovascular Imaging Research Center, Massachusetts General Hospital, Boston, MA, USA; Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA.
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Abohashem S, Grewal SS, Tawakol A, Osborne MT. Radionuclide Imaging of Heart-Brain Connections. Cardiol Clin 2023; 41:267-275. [PMID: 37003682 PMCID: PMC10152492 DOI: 10.1016/j.ccl.2023.01.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
The heart and brain have a complex interplay wherein disease or injury to either organ may adversely affect the other. The mechanisms underlying this connection remain incompletely characterized. However, nuclear molecular imaging is uniquely suited to investigate these pathways by facilitating the simultaneous assessment of both organs using targeted radiotracers. Research within this paradigm has demonstrated important roles for inflammation, autonomic nervous system and neurohormonal activity, metabolism, and perfusion in the heart-brain connection. Further mechanistic clarification may facilitate greater clinical awareness and the development of targeted therapies to alleviate the burden of disease in both organs.
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Affiliation(s)
- Shady Abohashem
- Department of Radiology, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA; Massachusetts General Hospital, Cardiovascular Imaging Research Center, 165 Cambridge Street, Suite 400, Boston, MA 02114, USA
| | - Simran S Grewal
- Massachusetts General Hospital, Cardiovascular Imaging Research Center, 165 Cambridge Street, Suite 400, Boston, MA 02114, USA; Division of Cardiology, Department of Medicine, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
| | - Ahmed Tawakol
- Massachusetts General Hospital, Cardiovascular Imaging Research Center, 165 Cambridge Street, Suite 400, Boston, MA 02114, USA; Division of Cardiology, Department of Medicine, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
| | - Michael T Osborne
- Massachusetts General Hospital, Cardiovascular Imaging Research Center, 165 Cambridge Street, Suite 400, Boston, MA 02114, USA; Division of Cardiology, Department of Medicine, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA.
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Abreu Diaz AM, Rodriguez Riera Z, Lee Y, Esteves LM, Normandeau CO, Fezas B, Hernandez Saiz A, Tournoux F, Juneau D, DaSilva JN. [ 18 F]Fluoropyridine-losartan: A new approach toward human Positron Emission Tomography imaging of Angiotensin II Type 1 receptors. J Labelled Comp Radiopharm 2023; 66:73-85. [PMID: 36656923 DOI: 10.1002/jlcr.4014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 12/27/2022] [Accepted: 01/17/2023] [Indexed: 01/21/2023]
Abstract
Angiotensin II type 1 receptors (AT1 R) blocker losartan is used in patients with renal and cardiovascular diseases. [18 F]fluoropyridine-losartan has shown favorable binding profile for quantitative renal PET imaging of AT1 R with selective binding in rats and pigs, low interference of radiometabolites and appropriate dosimetry for clinical translation. A new approach was developed to produce [18 F]fluoropyridine-losartan in very high molar activity. Automated radiosynthesis was performed in a three-step, two-pot, and two-HPLC-purification procedure within 2 h. Pure [18 F]FPyKYNE was obtained by radiofluorination of NO2 PyKYNE and silica-gel-HPLC purification (40 ± 9%), preventing the formation of nitropyridine-losartan in the second step. Conjugation with trityl-losartan azide via click chemistry, followed by acid hydrolysis, C18-HPLC purification and reformulation provided [18 F]fluoropyridine-losartan in 11 ± 2% (decay-corrected from [18 F]fluoride, EOB). Using tris[(1-(3-hydroxypropyl)-1H-1,2,3-triazol-4-yl)methyl]-amine (THPTA) as a Cu(I)-stabilizing agent for coupling [18 F]FPyKYNE to the unprotected losartan azide afforded [18 F]fluoropyridine-losartan in similar yields (11 ± 3%, decay-corrected from [18 F]fluoride, EOB). Reverse-phase HPLC was optimized by reducing the pH of the mobile phase to achieve complete purification and high molar activities (467 ± 60 GBq/μmol). The use of radioprotectants prevented tracer radiolysis for 10 h (RCP > 99%). The product passed the quality control testing. This reproducible automated radiosynthesis process will allow in vivo PET imaging of AT1 R expression in several diseases.
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Affiliation(s)
- Aida Mary Abreu Diaz
- Laboratoire de Radiochimie et Cyclotron, Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de pharmacologie et physiologie, Faculté de médecine, Université de Montréal, Pavillon Paul-G. Desmarais, Montréal, Québec, Canada
- Institut de génie biomédical, Faculté de médecine, Université de Montréal, Pavillon Paul-G. Desmarais, Montréal, Québec, Canada
- Departamento de Radioquímica, Instituto Superior de Tecnologías y Ciencias Aplicadas, Universidad de la Habana, La Habana, Cuba
| | - Zalua Rodriguez Riera
- Departamento de Radioquímica, Instituto Superior de Tecnologías y Ciencias Aplicadas, Universidad de la Habana, La Habana, Cuba
| | - Yanick Lee
- Laboratoire de Radiochimie et Cyclotron, Centre de Recherche du CHUM, Montréal, Québec, Canada
- Institut de génie biomédical, Faculté de médecine, Université de Montréal, Pavillon Paul-G. Desmarais, Montréal, Québec, Canada
| | - Luis Miguel Esteves
- Laboratoire de Radiochimie et Cyclotron, Centre de Recherche du CHUM, Montréal, Québec, Canada
- CRCHUM site, Isologic Innovative Radiopharmaceuticals, Lachine, Québec, Canada
| | | | - Baptiste Fezas
- Laboratoire de Radiochimie et Cyclotron, Centre de Recherche du CHUM, Montréal, Québec, Canada
| | | | - François Tournoux
- Laboratoire de Radiochimie et Cyclotron, Centre de Recherche du CHUM, Montréal, Québec, Canada
- Centre cardiovasculaire, Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
| | - Daniel Juneau
- Laboratoire de Radiochimie et Cyclotron, Centre de Recherche du CHUM, Montréal, Québec, Canada
- Médecine nucléaire, Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
- Département de radiologie, radio-oncologie et médecine nucléaire, Faculté de médecine, Université de Montréal, Pavillon Roger-Gaudry, Montréal, Québec, Canada
| | - Jean N DaSilva
- Laboratoire de Radiochimie et Cyclotron, Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de pharmacologie et physiologie, Faculté de médecine, Université de Montréal, Pavillon Paul-G. Desmarais, Montréal, Québec, Canada
- Institut de génie biomédical, Faculté de médecine, Université de Montréal, Pavillon Paul-G. Desmarais, Montréal, Québec, Canada
- Département de radiologie, radio-oncologie et médecine nucléaire, Faculté de médecine, Université de Montréal, Pavillon Roger-Gaudry, Montréal, Québec, Canada
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Metformin confers longitudinal cardiac protection by preserving mitochondrial homeostasis following myocardial ischemia/reperfusion injury. Eur J Nucl Med Mol Imaging 2023; 50:825-838. [PMID: 36322187 DOI: 10.1007/s00259-022-06008-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 10/12/2022] [Indexed: 11/06/2022]
Abstract
PURPOSE Myocardial ischemia-reperfusion (I/R) injury is associated with systemic oxidative stress, cardiac mitochondrial homeostasis, and cardiomyocyte apoptosis. Metformin has been recognized to attenuate cardiomyocyte apoptosis. However, the longitudinal effects and pathomechanism of metformin on the regulation of myocardial mitohormesis following I/R treatment remain unclear. This study aimed to investigate the longitudinal effects and mechanism of metformin in regulating cardiac mitochondrial homeostasis by serial imaging with the 18-kDa translocator protein (TSPO)-targeted positron emission tomography (PET) tracer 18F-FDPA. METHODS Myocardial I/R injury was established in Sprague-Dawley rats, which were treated with or without metformin (150 mg/kg per day). Serial gated 18F-FDG and 18F-FDPA PET imaging were performed at 1, 4, and 8 weeks after surgery, followed by analysis of ventricular remodelling and cardiac mitochondrial homeostasis. The correlation between Hsp60 and 18F-FDPA uptake was analyzed. After PET imaging, the activity of antioxidant enzymes, immunostaining, and western blot analysis were performed to analyze the spatio-temporal effects and pathomechanism of metformin for cardiac protection after myocardial I/R injury. RESULTS Oxidative stress and apoptosis increased 1 week after myocardial I/R injury (before significant progression of ventricular remodelling). TSPO expression was correlated with Hsp60 expression and was co-localized with inflammatory CD68+ macrophages in the infarct area, and TSPO uptake was associated with an upregulation of AMPK-p/AMPK and a downregulation of Bcl-2/Bax. However, these effects were reversed with metformin treatment. Eight weeks after myocardial I/R injury (representing the advanced stage of heart failure), 18F-FDPA uptake in myocardial cells in the distal non-infarct area increased without CD68+ expression, whereas the activity decreased with metformin treatment. CONCLUSION Taken together, these results show that a prolonged metformin treatment has pleiotropic protective effects against myocardial I/R injury associated with a regional and temporal dynamic balance between mitochondrial homeostasis and cardiac outcome, which were assessed by TSPO-targeted imaging during cardiac remodelling.
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Cardiac hybrid imaging: novel tracers for novel targets. JOURNAL OF GERIATRIC CARDIOLOGY : JGC 2021; 18:748-758. [PMID: 34659381 PMCID: PMC8501382 DOI: 10.11909/j.issn.1671-5411.2021.09.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Non-invasive cardiac imaging has explored enormous advances in the last few decades. In particular, hybrid imaging represents the fusion of information from multiple imaging modalities, allowing to provide a more comprehensive dataset compared to traditional imaging techniques in patients with cardiovascular diseases. The complementary anatomical, functional and molecular information provided by hybrid systems are able to simplify the evaluation procedure of various pathologies in a routine clinical setting. The diagnostic capability of hybrid imaging modalities can be further enhanced by introducing novel and specific imaging biomarkers. The aim of this review is to cover the most recent advancements in radiotracers development for SPECT/CT, PET/CT, and PET/MRI for cardiovascular diseases.
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Evaluation of the high affinity [ 18F]fluoropyridine-candesartan in rats for PET imaging of renal AT 1 receptors. Nucl Med Biol 2021; 96-97:41-49. [PMID: 33798796 DOI: 10.1016/j.nucmedbio.2021.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/01/2021] [Accepted: 03/11/2021] [Indexed: 11/23/2022]
Abstract
INTRODUCTION Alterations in the expression of the Angiotensin II type 1 receptors (AT1R) have been demonstrated in the development of several heart and renal diseases. The aim of this study was to evaluate the novel compound [18F]fluoropyridine-candesartan as a PET imaging tracer of AT1R in rat kidneys. METHODS Competition binding assays were carried out with membranes from CHO-K1 cells expressing human AT1R. Binding to plasma proteins was assessed by ultrafiltration. Radiolabeled metabolites in rat plasma and kidneys of control and pretreated animals (candesartan 10 mg/kg or losartan 30 mg/kg) were analyzed by column-switch HPLC. Dynamic PET/CT images of [18F]fluoropyridine-candesartan in male Sprague-Dawley rats were acquired for 60 min at baseline, pre-treatment with the AT1R antagonist losartan (30 mg/kg) or the AT2R antagonist PD123,319 (5 mg/kg). RESULTS Fluoropyridine-candesartan bound with a high affinity for AT1R (Ki = 5.9 ± 1.1 nM), comparable to fluoropyridine-losartan but lower than the parent compound candesartan (Ki = 0.4 ± 0.1 nM). [18F]Fluoropyridine-candesartan bound strongly to plasma proteins (99.3%) and was mainly metabolized to radiolabeled hydrophilic compounds, displaying minimal interference on renal AT1R binding with 82% of unchanged tracer in the kidneys at 20 min post-injection. PET imaging displayed high renal and liver accumulations and slow clearances, with maximum tissue-to-blood ratios of 14 ± 3 and 54 ± 12 in kidney cortex and liver, respectively, at 10 min post-injection. Binding specificity for AT1R was demonstrated with marked reductions in kidney cortex (-84%) and liver (-93%) tissue-to-blood ratios at 20 min post-injection, when blocking with AT1R antagonist losartan (30 mg/kg). No change was observed in kidney cortex of rats pre-treated with AT2R antagonist PD 123,319 (5 mg/kg), confirming binding selectivity for AT1 over AT2 receptors. CONCLUSION High kidney-to-blood ratios and binding selectivity to renal AT1R combined with tracer in vivo stability displaying minimal interference from labeled metabolites support further PET imaging studies with [18F]fluoropyridine-candesartan.
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Goud NS, Bhattacharya A, Joshi RK, Nagaraj C, Bharath RD, Kumar P. Carbon-11: Radiochemistry and Target-Based PET Molecular Imaging Applications in Oncology, Cardiology, and Neurology. J Med Chem 2021; 64:1223-1259. [PMID: 33499603 DOI: 10.1021/acs.jmedchem.0c01053] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The positron emission tomography (PET) molecular imaging technique has gained its universal value as a remarkable tool for medical diagnosis and biomedical research. Carbon-11 is one of the promising radiotracers that can report target-specific information related to its pharmacology and physiology to understand the disease status. Currently, many of the available carbon-11 (t1/2 = 20.4 min) PET radiotracers are heterocyclic derivatives that have been synthesized using carbon-11 inserted different functional groups obtained from primary and secondary carbon-11 precursors. A spectrum of carbon-11 PET radiotracers has been developed against many of the upregulated and emerging targets for the diagnosis, prognosis, prediction, and therapy in the fields of oncology, cardiology, and neurology. This review focuses on the carbon-11 radiochemistry and various target-specific PET molecular imaging agents used in tumor, heart, brain, and neuroinflammatory disease imaging along with its associated pathology.
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Affiliation(s)
- Nerella Sridhar Goud
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
| | - Ahana Bhattacharya
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
| | - Raman Kumar Joshi
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
| | - Chandana Nagaraj
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
| | - Rose Dawn Bharath
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
| | - Pardeep Kumar
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
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Abreu Diaz AM, Drumeva GO, Petrenyov DR, Carrier JF, DaSilva JN. Synthesis of the Novel AT 1 Receptor Tracer [ 18F]Fluoropyridine-Candesartan via Click Chemistry. ACS OMEGA 2020; 5:20353-20362. [PMID: 32832788 PMCID: PMC7439361 DOI: 10.1021/acsomega.0c02310] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 07/17/2020] [Indexed: 06/11/2023]
Abstract
A novel 7-((4-(3-((2-[18F]fluoropyridin-3-yl)oxy)propyl)-1H-1,2,3-triazol-1-yl)methyl)-1H-benzo[d]imidazole derivative of the angiotensin II type-1 receptor (AT1R) blocker candesartan, [18F]fluoropyridine-candesartan, was synthesized via the copper-catalyzed azide-alkyne cycloaddition click reaction between 2-[18F]fluoro-3-(pent-4-yn-1-yloxy)pyridine ([18F]FPyKYNE) and the tetrazole-protected azido-candesartan derivative, followed by acid deprotection. This three-step, two-pot, and two-step purification synthesis was done within 2 h. The use of tris[(1-hydroxypropyl-1H-1,2,3-triazol-4-yl)methyl]amine (THPTA) as a Cu(I) stabilizing agent increased the overall radiochemical yield by 4-fold (10 ± 2%, n = 13) compared to the reaction without THPTA (2.4 ± 0.2%, n = 3; decay-corrected from 18F produced at the end-of-beam). Complete separation of [18F]FPyKYNE from its nitro precursor and [18F]fluoropyridine-candesartan from the deprotected azido-candesartan allowed for high molar activities (>380 GBq/μmol) of the tracer. The use of 0.1% trifluoroacetic acid in water for reformulation and the addition of sodium ascorbate to the final formulation (1.6 ± 0.2 GBq/mL, n = 3) prevented tracer radiolysis with >97% radiochemical purity for a period of up to 10 h after the end-of-synthesis. A significant reduction in the uptake (86 ± 3%, n = 8) of the tracer was observed ex vivo in rats (at 20 min postinjection) in the AT1R-rich kidney cortex following pretreatment with saturating doses of the AT1R antagonist candesartan or losartan. This specific binding to AT1R was confirmed in vitro in the rat renal cortex (autoradiography) by a reduction of 26 ± 5% (n = 12) with losartan coincubation (10 μM). These favorable binding properties support further studies to assess the potential of [18F]fluoropyridine-candesartan as a tracer for the positron emission tomography imaging of renal AT1R.
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Affiliation(s)
- Aida M. Abreu Diaz
- Centre
de Recherche du CHUM, 900 rue Saint-Denis, Montréal, Québec H2X 0A9, Canada
- Département
de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Pavillon Paul-G. Desmarais, 2960
chemin de la Tour, Montréal, Québec H3T 1J4, Canada
- Institut
de Génie Biomédicale, Faculté de Médecine, Université de Montréal, Pavillon Paul-G. Desmarais, 2960
chemin de la Tour, Montréal, Québec H3T 1J4, Canada
- Departamento
de Radioquímica, Instituto Superior de Tecnologías y
Ciencias Aplicadas, Universidad de la Habana, Ave. Salvador Allende y Luaces,
Quinta de los Molinos, La Habana 10400, Cuba
| | - Gergana O. Drumeva
- Centre
de Recherche du CHUM, 900 rue Saint-Denis, Montréal, Québec H2X 0A9, Canada
- Département
de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Pavillon Paul-G. Desmarais, 2960
chemin de la Tour, Montréal, Québec H3T 1J4, Canada
| | - Daniil R. Petrenyov
- Centre
de Recherche du CHUM, 900 rue Saint-Denis, Montréal, Québec H2X 0A9, Canada
| | - Jean-François Carrier
- Centre
de Recherche du CHUM, 900 rue Saint-Denis, Montréal, Québec H2X 0A9, Canada
- Institut
de Génie Biomédicale, Faculté de Médecine, Université de Montréal, Pavillon Paul-G. Desmarais, 2960
chemin de la Tour, Montréal, Québec H3T 1J4, Canada
- Département
de Physique, Faculté des Arts et des Sciences, Université de Montréal, Complexe des Sciences, 1375 Avenue Thérèse-Lavoie-Roux, Montréal, Québec H2V 0B3, Canada
- Département
de Radiologie, Radio-Oncologie et Médecine Nucléaire,
Faculté de Médecine, Université
de Montréal, Pavillon
Roger-Gaudry, 2900 Boulevard Edouard Montpetit, Montréal, Québec H3T 1J4, Canada
| | - Jean N. DaSilva
- Centre
de Recherche du CHUM, 900 rue Saint-Denis, Montréal, Québec H2X 0A9, Canada
- Département
de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Pavillon Paul-G. Desmarais, 2960
chemin de la Tour, Montréal, Québec H3T 1J4, Canada
- Institut
de Génie Biomédicale, Faculté de Médecine, Université de Montréal, Pavillon Paul-G. Desmarais, 2960
chemin de la Tour, Montréal, Québec H3T 1J4, Canada
- Département
de Radiologie, Radio-Oncologie et Médecine Nucléaire,
Faculté de Médecine, Université
de Montréal, Pavillon
Roger-Gaudry, 2900 Boulevard Edouard Montpetit, Montréal, Québec H3T 1J4, Canada
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Bengel FM, Hermanns N, Thackeray JT. Radionuclide Imaging of the Molecular Mechanisms Linking Heart and Brain in Ischemic Syndromes. Circ Cardiovasc Imaging 2020; 13:e011303. [DOI: 10.1161/circimaging.120.011303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
For the heart and the brain, clinical observations suggest that an acute ischemic event experienced by one organ is associated with an increased risk for future acute events and chronic dysfunction of the reciprocal organ. Beyond atherosclerosis as a common systemic disease, various molecular mechanisms are thought to be involved in this interaction. Molecular-targeted nuclear imaging may identify the contribution of factors, such as the neurohumoral, circulatory, or especially the immune system, by combining specific radiotracers with whole-body acquisition and global as well as regional multiorgan analysis. This may be integrated with complementary functional imaging markers and systemic biomarkers for comprehensive network interrogation. Such systems-based strategies go beyond the traditional organ-centered approach and provide novel mechanistic insights, information about temporal dynamics, and a foundation for future interventions aiming at optimal preservation of function of both organs.
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Affiliation(s)
- Frank M. Bengel
- Department of Nuclear Medicine, Hannover Medical School, Germany
| | - Nele Hermanns
- Department of Nuclear Medicine, Hannover Medical School, Germany
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PET/CT Imaging of Cardiac Angiotensin II Type 1 Receptors in Nonobstructive Hypertrophic Cardiomyopathy. JACC Cardiovasc Imaging 2019; 12:1895-1896. [DOI: 10.1016/j.jcmg.2019.03.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 03/22/2019] [Accepted: 03/22/2019] [Indexed: 11/20/2022]
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Valenta I, Pacher P, Dilsizian V, Schindler TH. Novel Myocardial PET/CT Receptor Imaging and Potential Therapeutic Targets. Curr Cardiol Rep 2019; 21:55. [PMID: 31104205 DOI: 10.1007/s11886-019-1148-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
PURPOSE OF THE REVIEW Activation of myocardial cannabinoid type 1 receptors (CB1-R) and/or angiotensin II type 1 receptors (AT1-R) likely plays an important mechanistic role in determining the left-ventricular remodeling process in systolic heart failure. We provide an overview on novel radiotracer probes and positron emission tomography (PET)/computed tomography (CT) imaging to noninvasively probe the expression of myocardial CB1-R and/or AT1-R. RECENT FINDINGS Recent translational investigations have demonstrated the feasibility of 11C-OMAR or 11C-KR31173 and PET/CT to image and quantify myocardial CB1-R and/or AT1-R expression, respectively. There is an increasing understanding of the mechanisms of activated myocardial CB1-R and/or AT1-R to influence the left-ventricular remodeling process in systolic heart failure in different disease entities. The review summarizes contributions of PET to image myocardial CB1-R and AT1-R expression that may have the potential to serve as a target to tailor preventive medical care in the individual patient.
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Affiliation(s)
- Ines Valenta
- Mallinckrodt Institute of Radiology, Division of Nuclear Medicine, Washington University School of Medicine, Washington University in St. Louis, 510 S. Kingshighway Boulevard, Campus Box 8223, St. Louis, MO, 63110, USA
| | - Pal Pacher
- Laboratory of Physiological Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Vasken Dilsizian
- Department of Diagnostic Radiology and Nuclear Medicine, The University of Maryland School of Medicine, Baltimore, MD, USA
| | - Thomas H Schindler
- Mallinckrodt Institute of Radiology, Division of Nuclear Medicine, Washington University School of Medicine, Washington University in St. Louis, 510 S. Kingshighway Boulevard, Campus Box 8223, St. Louis, MO, 63110, USA.
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Boutagy NE, Feher A, Alkhalil I, Umoh N, Sinusas AJ. Molecular Imaging of the Heart. Compr Physiol 2019; 9:477-533. [PMID: 30873600 DOI: 10.1002/cphy.c180007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Multimodality cardiovascular imaging is routinely used to assess cardiac function, structure, and physiological parameters to facilitate the diagnosis, characterization, and phenotyping of numerous cardiovascular diseases (CVD), as well as allows for risk stratification and guidance in medical therapy decision-making. Although useful, these imaging strategies are unable to assess the underlying cellular and molecular processes that modulate pathophysiological changes. Over the last decade, there have been great advancements in imaging instrumentation and technology that have been paralleled by breakthroughs in probe development and image analysis. These advancements have been merged with discoveries in cellular/molecular cardiovascular biology to burgeon the field of cardiovascular molecular imaging. Cardiovascular molecular imaging aims to noninvasively detect and characterize underlying disease processes to facilitate early diagnosis, improve prognostication, and guide targeted therapy across the continuum of CVD. The most-widely used approaches for preclinical and clinical molecular imaging include radiotracers that allow for high-sensitivity in vivo detection and quantification of molecular processes with single photon emission computed tomography and positron emission tomography. This review will describe multimodality molecular imaging instrumentation along with established and novel molecular imaging targets and probes. We will highlight how molecular imaging has provided valuable insights in determining the underlying fundamental biology of a wide variety of CVDs, including: myocardial infarction, cardiac arrhythmias, and nonischemic and ischemic heart failure with reduced and preserved ejection fraction. In addition, the potential of molecular imaging to assist in the characterization and risk stratification of systemic diseases, such as amyloidosis and sarcoidosis will be discussed. © 2019 American Physiological Society. Compr Physiol 9:477-533, 2019.
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Affiliation(s)
- Nabil E Boutagy
- Department of Medicine, Yale Translational Research Imaging Center, Yale University School of Medicine, Section of Cardiovascular Medicine, New Haven, Connecticut, USA
| | - Attila Feher
- Department of Medicine, Yale Translational Research Imaging Center, Yale University School of Medicine, Section of Cardiovascular Medicine, New Haven, Connecticut, USA
| | - Imran Alkhalil
- Department of Medicine, Yale Translational Research Imaging Center, Yale University School of Medicine, Section of Cardiovascular Medicine, New Haven, Connecticut, USA
| | - Nsini Umoh
- Department of Medicine, Yale Translational Research Imaging Center, Yale University School of Medicine, Section of Cardiovascular Medicine, New Haven, Connecticut, USA
| | - Albert J Sinusas
- Department of Medicine, Yale Translational Research Imaging Center, Yale University School of Medicine, Section of Cardiovascular Medicine, New Haven, Connecticut, USA.,Yale University School of Medicine, Department of Radiology and Biomedical Imaging, New Haven, Connecticut, USA
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13
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Hoffmann M, Chen X, Hirano M, Arimitsu K, Kimura H, Higuchi T, Decker M. 18
F‐Labeled Derivatives of Irbesartan for Angiotensin II Receptor PET Imaging. ChemMedChem 2018; 13:2546-2557. [DOI: 10.1002/cmdc.201800638] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Indexed: 12/31/2022]
Affiliation(s)
- Matthias Hoffmann
- Pharmaceutical and Medicinal ChemistryInstitute of Pharmacy and Food ChemistryJulius Maximilian University Würzburg Am Hubland 97074 Würzburg Germany
| | - Xinyu Chen
- Department of Nuclear Medicine and Comprehensive Heart Failure Centre (CHFC)University Hospital of Würzburg Oberdürrbacherstr. 6 97080 Würzburg Germany
| | - Mitsuru Hirano
- Department of Bio-Medical ImagingNational Cerebral and Cardiovascular Centre, 5–7-1 Fujishiro-dai Suita Osaka 565-8565 Japan
| | - Kenji Arimitsu
- Department of Analytical and Bioinorganic ChemistryKyoto Pharmaceutical University 5 Nakauchi-Cho, Misasagi Yamashina-ku Kyoto 607–8414 Japan
| | - Hiroyuki Kimura
- Department of Analytical and Bioinorganic ChemistryKyoto Pharmaceutical University 5 Nakauchi-Cho, Misasagi Yamashina-ku Kyoto 607–8414 Japan
| | - Takahiro Higuchi
- Department of Nuclear Medicine and Comprehensive Heart Failure Centre (CHFC)University Hospital of Würzburg Oberdürrbacherstr. 6 97080 Würzburg Germany
- Department of Bio-Medical ImagingNational Cerebral and Cardiovascular Centre, 5–7-1 Fujishiro-dai Suita Osaka 565-8565 Japan
| | - Michael Decker
- Pharmaceutical and Medicinal ChemistryInstitute of Pharmacy and Food ChemistryJulius Maximilian University Würzburg Am Hubland 97074 Würzburg Germany
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14
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Chen X, Hirano M, Werner RA, Decker M, Higuchi T. Novel 18F-Labeled PET Imaging Agent FV45 Targeting the Renin-Angiotensin System. ACS OMEGA 2018; 3:10460-10470. [PMID: 30288456 PMCID: PMC6166228 DOI: 10.1021/acsomega.8b01885] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 08/14/2018] [Indexed: 06/08/2023]
Abstract
Renin-angiotensin system (RAS) plays an important role in the regulation of blood pressure and hormonal balance. Using positron emission tomography (PET) technology, it is possible to monitor the physiological and pathological distribution of angiotensin II type 1 receptors (AT1), which reflects the functionality of RAS. A new 18F-labeled PET tracer derived from the clinically used AT1 antagonist valsartan showing the least possible chemical alteration from the valsartan structure has been designed and synthesized with several strategies, which can be applied for the syntheses of further derivatives. Radioligand binding study showed that the cold reference FV45 (K i 14.6 nM) has almost equivalent binding affinity as its lead valsartan (K i 11.8 nM) and angiotensin II (K i 1.7 nM). Successful radiolabeling of FV45 in a one-pot radiofluorination followed by the deprotection procedure with 21.8 ± 8.5% radiochemical yield and >99% radiochemical purity (n = 5) enabled a distribution study in rats and opened a path to straightforward large-scale production. A fast and clear kidney uptake could be observed, and this renal uptake could be selectively blocked by pretreatment with AT1-selective antagonist valsartan. Overall, as the first 18F-labeled PET tracer based on a derivation from clinically used drug valsartan with almost identical chemical structure, [18F]FV45 will be a new tool for assessing the RAS function by visualizing AT1 receptor distributions and providing further information regarding cardiovascular system malfunction as well as possible applications in inflammation research and cancer diagnosis.
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Affiliation(s)
- Xinyu Chen
- Department
of Nuclear Medicine, Comprehensive Heart Failure Center, University
Hospital of Würzburg, Würzburg 97080, Germany
| | - Mitsuru Hirano
- Department
of Bio-Medical Imaging, National Cerebral
and Cardiovascular Center, Osaka 565-0873, Japan
| | - Rudolf A. Werner
- Department
of Nuclear Medicine, Comprehensive Heart Failure Center, University
Hospital of Würzburg, Würzburg 97080, Germany
- The
Russell H. Morgan Department of Radiology and Radiological Science,
Division of Nuclear Medicine and Molecular Imaging, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Michael Decker
- Institute of Pharmacy and Food Chemistry, University of Würzburg, Würzburg 97074, Germany
| | - Takahiro Higuchi
- Department
of Nuclear Medicine, Comprehensive Heart Failure Center, University
Hospital of Würzburg, Würzburg 97080, Germany
- Department
of Bio-Medical Imaging, National Cerebral
and Cardiovascular Center, Osaka 565-0873, Japan
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15
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Molecular imaging of cardiac remodelling after myocardial infarction. Basic Res Cardiol 2018; 113:10. [PMID: 29344827 PMCID: PMC5772148 DOI: 10.1007/s00395-018-0668-z] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 11/17/2017] [Accepted: 01/08/2018] [Indexed: 02/06/2023]
Abstract
Myocardial infarction and subsequent heart failure is a major health burden associated with significant mortality and morbidity in western societies. The ability of cardiac tissue to recover after myocardial infarction is affected by numerous complex cellular and molecular pathways. Unbalance or failure of these pathways can lead to adverse remodelling of the heart and poor prognosis. Current clinical cardiac imaging modalities assess anatomy, perfusion, function, and viability of the myocardium, yet do not offer any insight into the specific molecular pathways involved in the repair process. Novel imaging techniques allow visualisation of these molecular processes and may have significant diagnostic and prognostic values, which could aid clinical management. Single photon-emission tomography, positron-emission tomography, and magnetic resonance imaging are used to visualise various aspects of these molecular processes. Imaging probes are usually attached to radioisotopes or paramagnetic nanoparticles to specifically target biological processes such as: apoptosis, necrosis, inflammation, angiogenesis, and scar formation. Although the results from preclinical studies are promising, translating this work to a clinical environment in a valuable and cost-effective way is extremely challenging. Extensive evaluation evidence of diagnostic and prognostic values in multi-centre clinical trials is still required.
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16
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Shirani J, Singh A, Agrawal S, Dilsizian V. Cardiac molecular imaging to track left ventricular remodeling in heart failure. J Nucl Cardiol 2017; 24:574-590. [PMID: 27480973 DOI: 10.1007/s12350-016-0620-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 07/13/2016] [Indexed: 12/11/2022]
Abstract
Cardiac left ventricular (LV) remodeling is the final common pathway of most primary cardiovascular diseases that manifest clinically as heart failure (HF). The more advanced the systolic HF and LV dysfunction, the worse the prognosis. The knowledge of the molecular, cellular, and neurohormonal mechanisms that lead to myocardial dysfunction and symptomatic HF has expanded rapidly and has allowed sophisticated approaches to understanding and management of the disease. New therapeutic targets for pharmacologic intervention in HF have also been identified through discovery of novel cellular and molecular components of membrane-bound receptor-mediated intracellular signal transduction cascades. Despite all advances, however, the prognosis of systolic HF has remained poor in general. This is, at least in part, related to the (1) relatively late institution of treatment due to reliance on gross functional and structural abnormalities that define the "heart failure phenotype" clinically; (2) remarkable genetic-based interindividual variations in the contribution of each of the many molecular components of cardiac remodeling; and (3) inability to monitor the activity of individual pathways to cardiac remodeling in order to estimate the potential benefits of pharmacologic agents, monitor the need for dose titration, and minimize side effects. Imaging of the recognized ultrastructural components of cardiac remodeling can allow redefinition of heart failure based on its "molecular phenotype," and provide a guide to implementation of "personalized" and "evidence-based" evaluation, treatment, and longitudinal monitoring of the disease beyond what is currently available through randomized controlled clinical trials.
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Affiliation(s)
- Jamshid Shirani
- Department of Cardiology, St. Luke's University Health Network, 801 Ostrum Street, Bethlehem, PA, USA.
| | - Amitoj Singh
- Department of Cardiology, St. Luke's University Health Network, 801 Ostrum Street, Bethlehem, PA, USA
| | - Sahil Agrawal
- Department of Cardiology, St. Luke's University Health Network, 801 Ostrum Street, Bethlehem, PA, USA
| | - Vasken Dilsizian
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
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Lu T, Jiang B, Wang XL, Lee HC. Coronary arterial BK channel dysfunction exacerbates ischemia/reperfusion-induced myocardial injury in diabetic mice. Appl Physiol Nutr Metab 2016; 41:992-1001. [PMID: 27574914 DOI: 10.1139/apnm-2016-0048] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/01/2024]
Abstract
The large conductance Ca(2+)-activated K(+) (BK) channels, abundantly expressed in coronary artery smooth muscle cells (SMCs), play a pivotal role in regulating coronary circulation. A large body of evidence indicates that coronary arterial BK channel function is diminished in both type 1 and type 2 diabetes. However, the consequence of coronary BK channel dysfunction in diabetes is not clear. We hypothesized that impaired coronary BK channel function exacerbates myocardial ischemia/reperfusion (I/R) injury in streptozotocin-induced diabetic mice. Combining patch-clamp techniques and cellular biological approaches, we found that diabetes facilitated the colocalization of angiotensin II (Ang II) type 1 receptors and BK channel α-subunits (BK-α), but not BK channel β1-subunits (BK-β1), in the caveolae of coronary SMCs. This caveolar compartmentation in vascular SMCs not only enhanced Ang II-mediated inhibition of BK-α but also produced a physical disassociation between BK-α and BK-β1, leading to increased infarct size in diabetic hearts. Most importantly, genetic ablation of caveolae integrity or pharmacological activation of coronary BK channels protected the cardiac function of diabetic mice from experimental I/R injury in both in vivo and ex vivo preparations. Our results demonstrate a vascular ionic mechanism underlying the poor outcome of myocardial injury in diabetes. Hence, activation of coronary BK channels may serve as a therapeutic target for cardiovascular complications of diabetes.
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MESH Headings
- Angiotensin II/metabolism
- Angiotensin II Type 1 Receptor Blockers/pharmacology
- Animals
- Benzimidazoles/pharmacology
- Caveolae/drug effects
- Caveolae/metabolism
- Cells, Cultured
- Coronary Vessels/drug effects
- Coronary Vessels/metabolism
- Coronary Vessels/pathology
- Coronary Vessels/physiopathology
- Diabetic Cardiomyopathies/drug therapy
- Diabetic Cardiomyopathies/metabolism
- Diabetic Cardiomyopathies/pathology
- Diabetic Cardiomyopathies/physiopathology
- HEK293 Cells
- Humans
- Kv1.3 Potassium Channel
- Large-Conductance Calcium-Activated Potassium Channel alpha Subunits/agonists
- Large-Conductance Calcium-Activated Potassium Channel alpha Subunits/antagonists & inhibitors
- Large-Conductance Calcium-Activated Potassium Channel alpha Subunits/genetics
- Large-Conductance Calcium-Activated Potassium Channel alpha Subunits/metabolism
- Large-Conductance Calcium-Activated Potassium Channel beta Subunits/agonists
- Large-Conductance Calcium-Activated Potassium Channel beta Subunits/antagonists & inhibitors
- Large-Conductance Calcium-Activated Potassium Channel beta Subunits/genetics
- Large-Conductance Calcium-Activated Potassium Channel beta Subunits/metabolism
- Male
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Muscle, Smooth, Vascular/physiopathology
- Mutation
- Myocardial Reperfusion Injury/drug therapy
- Myocardial Reperfusion Injury/metabolism
- Myocardial Reperfusion Injury/pathology
- Myocardial Reperfusion Injury/physiopathology
- Protein Transport/drug effects
- Receptor, Angiotensin, Type 1/agonists
- Receptor, Angiotensin, Type 1/metabolism
- Recombinant Proteins/metabolism
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Affiliation(s)
- Tong Lu
- b Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Bin Jiang
- a Department of Cardiology, The First Affiliated Hospital of Soochow University, 108 Shixin Street, Soochow, Jiangsu 215006, P.R. China
- b Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Xiao-Li Wang
- b Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Hon-Chi Lee
- b Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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18
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Ismail B, deKemp RA, Hadizad T, Mackasey K, Beanlands RS, DaSilva JN. Decreased renal AT1 receptor binding in rats after subtotal nephrectomy: PET study with [(18)F]FPyKYNE-losartan. EJNMMI Res 2016; 6:55. [PMID: 27339045 PMCID: PMC4919198 DOI: 10.1186/s13550-016-0209-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 06/14/2016] [Indexed: 01/13/2023] Open
Abstract
Background Significant renal mass reduction induced by 5/6 subtotal nephrectomy (Nx) is associated with a chain of events that culminates in hypertension and chronic kidney disease (CKD). Numerous studies have provided evidence for the role of angiotensin (Ang) II type 1 receptor (AT1R) in the promotion and progression of the disease; however, conflicting results were reported on intrarenal AT1R levels in CKD models. Methods Male Sprague-Dawley rats (n = 26) underwent Nx or sham operations. Animals were scanned at 8–10 weeks post-surgery with PET using the novel AT1R radioligand [18F]FPyKYNE-losartan. Radioligand binding was quantified by kidney-to-blood ratio (KBR), standard uptake value (SUV), and distribution volume (DV). After sacrifice, plasma and kidney Ang II levels were measured. Western blot and 125I-[Sar1, Ile8]Ang II autoradiography were performed to assess AT1R expression. Results At 8–10 weeks post-surgery, Nx rats developed hypertension, elevated plasma creatinine levels, left ventricle hypertrophy, increased myocardial blood flow (MBF), and reduced Ang II levels compared to shams. PET measurements displayed significant decrease in KBR (29 %), SUV (24 %), and DV (22 %) induced by Nx (p < 0.05), and these findings were confirmed by in vitro assays. Conclusions Reduced renal AT1Rs in hypertensive rats measured with [18F]FPyKYNE-losartan PET at 8–10 weeks following Nx support further use of this non-invasive approach in longitudinal studies to better understand the AT1R role in CKD progression.
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Affiliation(s)
- Basma Ismail
- National Cardiac PET Centre, University of Ottawa Heart Institute, 40 Ruskin St., Ottawa, ON, K1Y 4W7, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Robert A deKemp
- National Cardiac PET Centre, University of Ottawa Heart Institute, 40 Ruskin St., Ottawa, ON, K1Y 4W7, Canada
| | - Tayebeh Hadizad
- National Cardiac PET Centre, University of Ottawa Heart Institute, 40 Ruskin St., Ottawa, ON, K1Y 4W7, Canada
| | - Kumiko Mackasey
- National Cardiac PET Centre, University of Ottawa Heart Institute, 40 Ruskin St., Ottawa, ON, K1Y 4W7, Canada
| | - Rob S Beanlands
- National Cardiac PET Centre, University of Ottawa Heart Institute, 40 Ruskin St., Ottawa, ON, K1Y 4W7, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Jean N DaSilva
- National Cardiac PET Centre, University of Ottawa Heart Institute, 40 Ruskin St., Ottawa, ON, K1Y 4W7, Canada. .,Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada. .,Department of Radiology, Radio-Oncology and Nuclear Medicine, University of Montreal, University of Montreal Hospital Research Centre (CRCHUM), 900 Rue Saint-Denis, Montréal, Québec, H2X 0A9, Canada.
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19
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Papadimitriou L, Smith-Jones PM, Sarwar CM, Marti CN, Yaddanapudi K, Skopicki HA, Gheorghiade M, Parsey R, Butler J. Utility of positron emission tomography for drug development for heart failure. Am Heart J 2016; 175:142-52. [PMID: 27179733 DOI: 10.1016/j.ahj.2016.02.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Accepted: 02/22/2016] [Indexed: 12/14/2022]
Abstract
Only about 1 in 5,000 investigational agents in a preclinical stage acquires Food and Drug Administration approval. Among many reasons for this includes an inefficient transition from preclinical to clinical phases, which exponentially increase the cost and the delays the process of drug development. Positron emission tomography (PET) is a nuclear imaging technique that has been used for the diagnosis, risk stratification, and guidance of therapy. However, lately with the advance of radiochemistry and of molecular imaging technology, it became evident that PET could help novel drug development process. By using a PET radioligand to report on receptor occupancy during novel agent therapy, it may help assess the effectiveness, efficacy, and safety of such a new medication in an early preclinical stage and help design successful clinical trials even at a later phase. In this article, we explore the potential implications of PET in the development of new heart failure therapies and review PET's application in the respective pathophysiologic pathways such as myocardial perfusion, metabolism, innervation, inflammation, apoptosis, and cardiac remodeling.
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20
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21
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Ismail B, Hadizad T, Antoun R, Lortie M, deKemp RA, Beanlands RS, DaSilva JN. Evaluation of [11C]methyl-losartan and [11C]methyl-EXP3174 for PET imaging of renal AT1receptor in rats. Nucl Med Biol 2015; 42:850-7. [DOI: 10.1016/j.nucmedbio.2015.06.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 05/04/2015] [Accepted: 06/24/2015] [Indexed: 10/23/2022]
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22
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Werner RA, Maya Y, Rischpler C, Javadi MS, Fukushima K, Lapa C, Herrmann K, Higuchi T. Sympathetic nerve damage and restoration after ischemia-reperfusion injury as assessed by (11)C-hydroxyephedrine. Eur J Nucl Med Mol Imaging 2015; 43:312-318. [PMID: 26290424 DOI: 10.1007/s00259-015-3171-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 08/10/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE An altered state of the cardiac sympathetic nerves is an important prognostic factor in patients with coronary artery disease. The aim of this study was to investigate regional sympathetic nerve damage and restoration utilizing a rat model of myocardial transient ischemia and a catecholamine analog PET tracer, (11)C-hydroxyephedrine ((11)C-HED). METHODS Transient myocardial ischemia was induced by coronary occlusion for 20 min and reperfusion in male Wistar rats. Dual-tracer autoradiography was performed subacutely (7 days) and chronically (2 months) after ischemia, and in control rats without ischemia using (11)C-HED as a marker of sympathetic innervation and (201)TI for perfusion. Additional serial in vivo cardiac (11)C-HED and (18)F-FDG PET scans were performed in the subacute and chronic phases after ischemia. RESULTS After transient ischemia, the (11)C-HED uptake defect areas in both the subacute and chronic phases were clearly larger than the perfusion defect areas in the midventricular wall. The subacute (11)C-HED uptake defect showed a transmural pattern, whereas uptake recovered in the subepicardial portion in the chronic phase. Tyrosine hydroxylase antibody nerve staining confirmed regional denervation corresponding to areas of decreased (11)C-HED uptake. Serial in vivo PET imaging visualized reductions in the area of the (11)C-HED uptake defects in the chronic phase consistent with autoradiography and histology. CONCLUSION Higher susceptibility of sympathetic neurons compared to myocytes was confirmed by a larger (11)C-HED defect with a corresponding histologically identified region of denervation. Furthermore, partial reinnervation was observed in the chronic phase as shown by recovery of subepicardial (11)C-HED uptake.
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Affiliation(s)
- Rudolf A Werner
- Department of Nuclear Medicine, University of Würzburg, Oberdürrbacher Strasse 6, 97080, Würzburg, Germany.,Comprehensive Heart Failure Center, University of Würzburg, Oberdürrbacher Strasse 6, 97080, Würzburg, Germany
| | - Yoshifumi Maya
- Department of Nuclear Medicine, University of Würzburg, Oberdürrbacher Strasse 6, 97080, Würzburg, Germany.,Research Centre, Nihon Medi-Physics Co., Ltd., Chiba, Japan
| | - Christoph Rischpler
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, München, Germany
| | - Mehrbod S Javadi
- Division of Nuclear Medicine, Russell H. Morgan Department of Radiology, Johns Hopkins University, Baltimore, MD, USA
| | | | - Constantin Lapa
- Department of Nuclear Medicine, University of Würzburg, Oberdürrbacher Strasse 6, 97080, Würzburg, Germany
| | - Ken Herrmann
- Department of Nuclear Medicine, University of Würzburg, Oberdürrbacher Strasse 6, 97080, Würzburg, Germany.,Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Takahiro Higuchi
- Department of Nuclear Medicine, University of Würzburg, Oberdürrbacher Strasse 6, 97080, Würzburg, Germany. .,Comprehensive Heart Failure Center, University of Würzburg, Oberdürrbacher Strasse 6, 97080, Würzburg, Germany.
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Hennig R, Pollinger K, Tessmar J, Goepferich A. Multivalent targeting of AT1 receptors with angiotensin II-functionalized nanoparticles. J Drug Target 2015; 23:681-9. [PMID: 25950599 DOI: 10.3109/1061186x.2015.1035276] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The angiotensin II receptor type 1 (AT1R) is a G protein-coupled receptor of paramount significance since it is overexpressed in a number of diseased tissues that are highly attractive for nanoparticle targeting. However, it is also expressed at physiological levels in healthy tissue. Multivalent interactions mediated by multiple AT1R-binding moieties per nanoparticle could promote a high binding avidity to AT1R overexpressing cells and concomitantly spare off-target tissue. To investigate the feasibility of this approach, angiotensin II was thiolated and conjugated to PEGylated quantum dots. Nanoparticle binding, uptake and affinity to several cell lines was investigated in detail. The colloids were rapidly taken up by clathrin-mediated endocytosis into AT1R-expressing cells and showed no interaction with receptor negative cells. The EC50 of the thiolated angiotensin II was determined to be 261 nM, whereas the ligand-conjugated Qdots activated the receptor with an EC50 of 8.9 nM. This 30-fold higher affinity of the nanoparticles compared to the unconjugated peptide clearly demonstrated the presence of multivalent effects when using agonist-targeted nanoparticles. Our study provides compelling evidence that, despite being immediately endocytosed, Ang II-coupled nanoparticles exert potent multivalent ligand-receptor interactions that can be used to establish high affinities to an AT1R overexpressing cell and tissue.
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Affiliation(s)
- Robert Hennig
- a Department of Pharmaceutical Technology , University of Regensburg , Regensburg , Germany and
| | - Klaus Pollinger
- a Department of Pharmaceutical Technology , University of Regensburg , Regensburg , Germany and
| | - Joerg Tessmar
- b Department for Functional Materials in Medicine and Dentistry , University Hospital of Wuerzburg , Wuerzburg , Germany
| | - Achim Goepferich
- a Department of Pharmaceutical Technology , University of Regensburg , Regensburg , Germany and
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24
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Chen X, Werner RA, Javadi MS, Maya Y, Decker M, Lapa C, Herrmann K, Higuchi T. Radionuclide imaging of neurohormonal system of the heart. Am J Cancer Res 2015; 5:545-58. [PMID: 25825596 PMCID: PMC4377725 DOI: 10.7150/thno.10900] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 01/02/2015] [Indexed: 12/18/2022] Open
Abstract
Heart failure is one of the growing causes of death especially in developed countries due to longer life expectancy. Although many pharmacological and instrumental therapeutic approaches have been introduced for prevention and treatment of heart failure, there are still limitations and challenges. Nuclear cardiology has experienced rapid growth in the last few decades, in particular the application of single photon emission computed tomography (SPECT) and positron emission tomography (PET), which allow non-invasive functional assessment of cardiac condition including neurohormonal systems involved in heart failure; its application has dramatically improved the capacity for fundamental research and clinical diagnosis. In this article, we review the current status of applying radionuclide technology in non-invasive imaging of neurohormonal system in the heart, especially focusing on the tracers that are currently available. A short discussion about disadvantages and perspectives is also included.
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Abstract
Angiotensin II (AII), an octapeptide member of the renin-angiotensin system (RAS), is formed by the enzyme angiotensin converting enzyme (ACE) and exerts adverse cellular effects through an interaction with its type 1 receptor (AT1R). Both ACE inhibitors and angiotensin receptor blockers (ARB) mitigate the vasoconstrictive, proliferative, proinflammatory, proapoptotic, and profibrotic effects of AII and are widely used as effective anti-remodeling agents in clinical practice. Prediction of individual response to these agents, however, remains problematic and is influenced by many factors including race, gender, and genotype. In addition, systemic and tissue RAS activity do not correlate closely. This report summarizes the results of on-going attempts to noninvasively determine tissue ACE activity and AT1R expression using novel nuclear tracers. It is hoped that the availability of such imaging techniques improve treatment of heart failure through more selective pharmacologic intervention and better dose titration of available drugs.
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Lautamäki R, Knuuti J, Saraste A. Recent Developments in Imaging of Myocardial Angiotensin Receptors. CURRENT CARDIOVASCULAR IMAGING REPORTS 2013. [DOI: 10.1007/s12410-013-9245-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Modeling of the renal kinetics of the AT1 receptor specific PET radioligand [11C]KR31173. BIOMED RESEARCH INTERNATIONAL 2013; 2013:835859. [PMID: 24083243 PMCID: PMC3780470 DOI: 10.1155/2013/835859] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Accepted: 07/17/2013] [Indexed: 11/18/2022]
Abstract
Purpose. The radioligand [11C]KR31173 has been introduced for PET imaging of the angiotensin II subtype 1 receptor (AT1R). The purpose of the present project was to employ and validate a compartmental model for quantification of the kinetics of this radioligand in a porcine model of renal ischemia followed by reperfusion (IR). Procedures. Ten domestic pigs were included in the study: five controls and five experimental animals with IR of the left kidney. To achieve IR, acute ischemia was created with a balloon inserted into the left renal artery and inflated for 60 minutes. Reperfusion was achieved by deflation and removal of the balloon. Blood chemistries, urine specific gravity and PH values, and circulating hormones of the renin angiotensin system were measured and PET imaging was performed one week after IR. Cortical time-activity curves obtained from a 90 min [11C]KR31173 dynamic PET study were processed with a compartmental model that included two tissue compartments connected in parallel. Radioligand binding quantified by radioligand retention (80 min value to maximum value ratio) was compared to the binding parameters derived from the compartmental model. A binding ratio was calculated as DVR = DVS/DVNS, where DVS and DVNS represented the distribution volumes of specific binding and nonspecific binding. Receptor binding was also determined by autoradiography in vitro. Results. Correlations between rate constants and binding parameters derived by the convolution and deconvolution curve fittings were significant (r > 0.9). Also significant was the correlation between the retention parameter derived from the tissue activity curve (Yret) and the retention parameter derived from the impulse response function (fret). Furthermore, significant correlations were found between these two retention parameters and DVR. Measurements with PET showed no significant changes in the radioligand binding parameters caused by IR, and these in vivo findings were confirmed by autoradiography performed in vitro. Conclusions. Correlations between various binding parameters support the concept of the parallel connectivity compartmental model. If an arterial input function cannot be obtained, simple radioligand retention may be adequate for estimation of in vivo radioligand binding.
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Bengel FM, George RT, Schuleri KH, Lardo AC, Wollert KC. Image-guided therapies for myocardial repair: concepts and practical implementation. Eur Heart J Cardiovasc Imaging 2013; 14:741-51. [PMID: 23720377 DOI: 10.1093/ehjci/jet038] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Cell- and molecule-based therapeutic strategies to support wound healing and regeneration after myocardial infarction (MI) are under development. These emerging therapies aim at sustained preservation of ventricular function by enhancing tissue repair after myocardial ischaemia and reperfusion. Such therapies will benefit from guidance with regard to timing, regional targeting, suitable candidate selection, and effectiveness monitoring. Such guidance is effectively obtained by non-invasive tomographic imaging. Infarct size, tissue characteristics, muscle mass, and chamber geometry can be determined by magnetic resonance imaging and computed tomography. Radionuclide imaging can be used for the tracking of therapeutic agents and for the interrogation of molecular mechanisms such as inflammation, angiogenesis, and extracellular matrix activation. This review article portrays the hypothesis that an integrated approach with an early implementation of structural and molecular tomographic imaging in the development of novel therapies will provide a framework for achieving the goal of improved tissue repair after MI.
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Affiliation(s)
- Frank M Bengel
- Department of Nuclear Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, Hannover 30625, Germany.
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Cardiac Micro-PET-CT. CURRENT CARDIOVASCULAR IMAGING REPORTS 2013. [DOI: 10.1007/s12410-012-9188-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Discrepant uptake of the radiolabeled norepinephrine analogues hydroxyephedrine (HED) and metaiodobenzylguanidine (MIBG) in rat hearts. Eur J Nucl Med Mol Imaging 2013; 40:1077-83. [DOI: 10.1007/s00259-013-2393-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 03/07/2013] [Indexed: 01/08/2023]
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Fukushima K, Bravo PE, Higuchi T, Schuleri KH, Lin X, Abraham MR, Xia J, Mathews WB, Dannals RF, Lardo AC, Szabo Z, Bengel FM. Molecular hybrid positron emission tomography/computed tomography imaging of cardiac angiotensin II type 1 receptors. J Am Coll Cardiol 2012; 60:2527-34. [PMID: 23158533 DOI: 10.1016/j.jacc.2012.09.023] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 09/05/2012] [Accepted: 09/25/2012] [Indexed: 11/29/2022]
Abstract
OBJECTIVES The goal of this study was to explore the feasibility of targeted imaging of the angiotensin II type 1 receptor (AT1R) in cardiac tissue, using clinical hybrid positron emission tomography/computed tomography (PET/CT). BACKGROUND AT1R is an attractive imaging target due to its key role in various cardiac pathologies, including post-infarct left ventricular remodeling. METHODS Using the novel AT1R ligand [(11)C]-KR31173, dynamic PET/CT was performed in young farm pigs under healthy conditions (n = 4) and 3 to 4 weeks after experimental myocardial infarction (n = 5). Ex vivo validation was carried out by immunohistochemistry and polymerase chain reaction. First-in-man application was performed in 4 healthy volunteers at baseline and under AT1R blocking. RESULTS In healthy pigs, myocardial KR31173 retention was detectable, regionally homogeneous, and specific for AT1R, as confirmed by blocking experiments. Metabolism in plasma was low (85 ± 2% of intact tracer after 60 min). After myocardial infarction, KR31173 retention, corrected for regional perfusion, revealed AT1R up-regulation in the infarct area relative to remote myocardium, whereas retention was elevated in both regions when compared with myocardium of healthy controls (8.7 ± 0.8% and 7.1 ± 0.3%/min vs. 5.8 ± 0.4%/min for infarct and remote, respectively, vs. healthy controls; p < 0.01 each). Postmortem analysis confirmed AT1R up-regulation in remote and infarct tissue. First-in-man application was safe, and showed detectable and specific myocardial KR31173 retention, albeit at a lower level than pigs (left ventricular average retention: 1.2 ± 0.1%/min vs. 4.4 ± 1.2%/min for humans vs. pigs; p = 0.04). CONCLUSIONS Noninvasive imaging of cardiac AT1R expression is feasible using clinical PET/CT technology. Results provide a rationale for broader clinical testing of AT1R-targeted molecular imaging.
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Affiliation(s)
- Kenji Fukushima
- Division of Nuclear Medicine, Russell H. Morgan Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
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Affiliation(s)
- Frank M Bengel
- Department of Nuclear Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
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Perfusion defect size predicts engraftment but not early retention of intra-myocardially injected cardiosphere-derived cells after acute myocardial infarction. Basic Res Cardiol 2011; 106:1379-86. [PMID: 21706191 PMCID: PMC3228962 DOI: 10.1007/s00395-011-0197-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 05/13/2011] [Accepted: 06/13/2011] [Indexed: 11/29/2022]
Abstract
Therapeutic cell retention and engraftment are critical for myocardial regeneration. Underlying mechanisms, including the role of tissue perfusion, are not well understood. In Wistar Kyoto rats, syngeneic cardiosphere-derived cells (CDCs) were injected intramyocardially, after experimental myocardial infarction. CDCs were labeled with [18F]-FDG (n = 7), for quantification of 1-h retention, or with sodium-iodide-symporter gene (NIS; n = 8), for detection of 24-h engraftment by reporter imaging. Perfusion was imaged simultaneously. Infarct size was 37 ± 9 and 38 ± 9% of LV in FDG and NIS groups. Cell signal was located in the infarct border zone in all animals. No significant relationship was observed between infarct size and 1-h CDC retention (r = −0.65; P = 0.11). However, infarct size correlated significantly with 24-h engraftment (r = 0.75; P = 0.03). Residual perfusion at the injection site was not related to cell retention/engraftment. Larger infarcts are associated with improved CDC engraftment. This observation encourages further investigation of microenvironmental conditions after ischemic damage and their role in therapeutic cell survival.
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