1
|
Ruddy TD, Davies RA, Kiess MC. Development and evolution of nuclear cardiology and cardiac PET in Canada. J Med Imaging Radiat Sci 2024; 55:S3-S9. [PMID: 38637261 DOI: 10.1016/j.jmir.2024.03.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Revised: 03/22/2024] [Accepted: 03/25/2024] [Indexed: 04/20/2024]
Abstract
Gated radionuclide angiography and myocardial perfusion imaging were developed in the United States and Europe in the 1970's and soon adopted in Canadian centers. Much of the early development of nuclear cardiology in Canada was in Toronto, Ontario and was quickly followed by new programs across the country. Clinical research in Canada contributed to the further development of nuclear cardiology and cardiac PET. The Canadian Nuclear Cardiology Society (CNCS) was formed in 1995 and became the Canadian Society of Cardiovascular Nuclear and CT Imaging (CNCT) in 2014. The CNCS had a major role in education and advocacy for cardiovascular nuclear medicine testing. The CNCS established the Dr Robert Burns Lecture and CNCT named the Canadian Society of Cardiovascular Nuclear and CT Imaging Annual Achievement Award for Dr Michael Freeman in memoriam of these two outstanding Canadian leaders in nuclear cardiology. The future of nuclear cardiology in Canada is exciting with the expanding use of SPECT imaging to include Tc-99m-pyrophosphate for diagnosis of transthyretin cardiac amyloidosis and the ongoing introduction of cardiac PET imaging.
Collapse
Affiliation(s)
- Terrence D Ruddy
- Division of Cardiology, University of Ottawa Heart Institute, Ottawa, Ontario, Canada.
| | - Ross A Davies
- Division of Cardiology, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
| | - Marla C Kiess
- Division of Cardiology, University of British Columbia, St. Paul's Hospital, Vancouver, British Columbia, Canada
| |
Collapse
|
2
|
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.
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
Synthesis and Evaluation of [ 18F]FEtLos and [ 18F]AMBF 3Los as Novel 18F-Labelled Losartan Derivatives for Molecular Imaging of Angiotensin II Type 1 Receptors. Molecules 2020; 25:molecules25081872. [PMID: 32325695 PMCID: PMC7221519 DOI: 10.3390/molecules25081872] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/18/2020] [Accepted: 01/23/2020] [Indexed: 01/13/2023] Open
Abstract
Losartan is widely used in clinics to treat cardiovascular related diseases by selectively blocking the angiotensin II type 1 receptors (AT1Rs), which regulate the renin-angiotensin system (RAS). Therefore, monitoring the physiological and pathological biodistribution of AT1R using positron emission tomography (PET) might be a valuable tool to assess the functionality of RAS. Herein, we describe the synthesis and characterization of two novel losartan derivatives PET tracers, [18F]fluoroethyl-losartan ([18F]FEtLos) and [18F]ammoniomethyltrifluoroborate-losartan ([18F]AMBF3Los). [18F]FEtLos was radiolabeled by 18F-fluoroalkylation of losartan potassium using the prosthetic group 2-[18F]fluoroethyl tosylate; whereas [18F]AMBF3Los was prepared following an one-step 18F-19F isotopic exchange reaction, in an overall yield of 2.7 ± 0.9% and 11 ± 4%, respectively, with high radiochemical purity (>95%). Binding competition assays in AT1R-expressing membranes showed that AMBF3Los presented an almost equivalent binding affinity (Ki 7.9 nM) as the cold reference Losartan (Ki 1.5 nM), unlike FEtLos (Ki 2000 nM). In vitro and in vivo assays showed that [18F]AMBF3Los displayed a good binding affinity for AT1R-overexpressing CHO cells and was able to specifically bind to renal AT1R. Hence, our data demonstrate [18F]AMBF3Los as a new tool for PET imaging of AT1R with possible applications for the diagnosis of cardiovascular, inflammatory and cancer diseases.
Collapse
|
5
|
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
| |
Collapse
|
6
|
Ismail B, deKemp RA, Croteau E, Hadizad T, Burns KD, Beanlands RS, DaSilva JN. Treatment with enalapril and not diltiazem ameliorated progression of chronic kidney disease in rats, and normalized renal AT1 receptor expression as measured with PET imaging. PLoS One 2017; 12:e0177451. [PMID: 28542215 PMCID: PMC5438116 DOI: 10.1371/journal.pone.0177451] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 04/27/2017] [Indexed: 12/23/2022] Open
Abstract
ACE inhibitors are considered first line of treatment in patients with many forms of chronic kidney disease (CKD). Other antihypertensives such as calcium channel blockers achieve similar therapeutic effectiveness in attenuating hypertension-related renal damage progression. Our objective was to explore the value of positron emission tomography (PET) imaging of renal AT1 receptor (AT1R) to guide therapy in the 5/6 subtotal-nephrectomy (Nx) rat model of CKD. Ten weeks after Nx, Sprague-Dawley rats were administered 10mg/kg/d enalapril (NxE), 30mg/kg/d diltiazem (NxD) or left untreated (Nx) for an additional 8-10 weeks. Kidney AT1R expression was assessed using in vivo [18F]fluoropyridine-losartan PET and in vitro autoradiography. Compared to shams, Nx rats exhibited higher systolic blood pressure that was reduced by both enalapril and diltiazem. At 18-20 weeks, plasma creatinine and albuminuria were significantly increased in Nx, reduced to sham levels in NxE, but enhanced in NxD rats. Enalapril treatment decreased kidney angiotensin II whereas diltiazem induced significant elevations in plasma and kidney levels. Reduced PET renal AT1R levels in Nx were normalized by enalapril but not diltiazem, and results were supported by autoradiography. Reduction of renal blood flow in Nx was restored by enalapril, while no difference was observed in myocardial blood flow amongst groups. Enhanced left ventricle mass in Nx was not reversed by enalapril but was augmented with diltiazem. Stroke volume was diminished in untreated Nx compared to shams and restored with both therapies. [18F]Fluoropyridine-Losartan PET allowed in vivo quantification of kidney AT1R changes associated with progression of CKD and with various pharmacotherapies.
Collapse
Affiliation(s)
- Basma Ismail
- Cardiac PET Centre, Department of Medicine (Division of Cardiology), University of Ottawa Heart Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Rob A. deKemp
- Cardiac PET Centre, Department of Medicine (Division of Cardiology), University of Ottawa Heart Institute, Ottawa, ON, Canada
| | - Etienne Croteau
- Cardiac PET Centre, Department of Medicine (Division of Cardiology), University of Ottawa Heart Institute, Ottawa, ON, Canada
| | - Tayebeh Hadizad
- Cardiac PET Centre, Department of Medicine (Division of Cardiology), University of Ottawa Heart Institute, Ottawa, ON, Canada
| | - Kevin D. Burns
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
- Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ontario, Canada
| | - Rob S. Beanlands
- Cardiac PET Centre, Department of Medicine (Division of Cardiology), University of Ottawa Heart Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Jean N. DaSilva
- Cardiac PET Centre, Department of Medicine (Division of Cardiology), University of Ottawa Heart Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
- Department of Radiology, Radio-Oncology and Nuclear Medicine, University of Montreal; University of Montreal Hospital Research Centre (CRCHUM), Montréal, Québec, Canada
- * E-mail:
| |
Collapse
|
7
|
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.
Collapse
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
| |
Collapse
|
8
|
Hachem M, Tiberi M, Ismail B, Hunter CR, Arksey N, Hadizad T, Beanlands RS, deKemp RA, DaSilva JN. Characterization of 18F-FPyKYNE-Losartan for Imaging AT1 Receptors. J Nucl Med 2016; 57:1612-1617. [DOI: 10.2967/jnumed.115.170951] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 04/11/2016] [Indexed: 12/25/2022] Open
|
9
|
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.
Collapse
|
10
|
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]
|
11
|
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.
Collapse
|
12
|
Abstract
There is an expanding and exciting repertoire of PET imaging radiotracers for urogenital diseases, particularly in prostate cancer, renal cell cancer, and renal function. Prostate cancer is the most commonly diagnosed cancer in men. With growing therapeutic options for the treatment of metastatic and advanced prostate cancer, improved functional imaging of prostate cancer beyond the limitations of conventional CT and bone scan is becoming increasingly important for both clinical management and drug development. PET radiotracers, apart from ¹⁸F-FDG, for prostate cancer are ¹⁸F-sodium fluoride, ¹¹C-choline, and ¹⁸F-fluorocholine, and (¹¹C-acetate. Other emerging and promising PET radiotracers include a synthetic l-leucine amino acid analogue (anti-¹⁸F-fluorocyclobutane-1-carboxylic acid), dihydrotestosterone analogue (¹⁸F-fluoro-5α-dihydrotestosterone), and prostate-specific membrane antigen-based PET radiotracers (eg, N-[N-[(S)-1,3-dicarboxypropyl]carbamoyl]-4-¹⁸F-fluorobenzyl-l-cysteine, ⁸⁹Zr-DFO-J591, and ⁶⁸Ga [HBED-CC]). Larger prospective and comparison trials of these PET radiotracers are needed to establish the role of PET/CT in prostate cancer. Although renal cell cancer imaging with FDG-PET/CT is available, it can be limited, especially for detection of the primary tumor. Improved renal cell cancer detection with carbonic anhydrase IX (CAIX)-based antibody (¹²⁴I-girentuximab) and radioimmunotherapy targeting with ¹⁷⁷Lu-cG250 appear promising. Evaluation of renal injury by imaging renal perfusion and function with novel PET radiotracers include p-¹⁸F-fluorohippurate, hippurate m-cyano-p-¹⁸F-fluorohippurate, and rubidium-82 chloride (typically used for myocardial perfusion imaging). Renal receptor imaging of the renal renin-angiotensin system with a variety of selective PET radioligands is also becoming available for clinical translation.
Collapse
Affiliation(s)
- Steve Y Cho
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins School of Medicine, Baltimore, MD
| | - Zsolt Szabo
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins School of Medicine, Baltimore, MD.
| |
Collapse
|
13
|
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]
|