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Lewkowicz E, Jayaraman S, Gursky O. Molecular basis for non-invasive diagnostics of cardiac amyloids using bone tracers. Biomater Sci 2024; 12:4275-4282. [PMID: 39046441 PMCID: PMC11334954 DOI: 10.1039/d4bm00816b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Accepted: 07/19/2024] [Indexed: 07/25/2024]
Abstract
Amyloid diseases including Alzheimer's, Parkinson's and over 30 others are incurable life-threatening disorders caused by abnormal protein deposition as fibrils in various organs. Cardiac amyloidosis is particularly challenging to diagnose and treat. Identification of the fibril-forming protein, which in the heart is usually amyloid transthyretin (ATTR) or amyloid immunoglobulin light chain (AL), is paramount to treatment. A transformative non-invasive diagnostic modality is imaging using technetium-labeled pyrophosphate or diphosphonate bone tracers, 99mTc-PYP/DPD/HMDP. For unknown reasons, these tracers show preferential uptake by ATTR deposits. The tracer-binding moiety is unknown and potentially involves amyloid fibrils and/or amyloid-associated calcific deposits. We propose that, like in the bone, the tracers chelate to surface-bound Ca2+ in amyloid. In high-affinity protein sites, Ca2+ is coordinated by pairs of acidic residues. To identify such residues on amyloids, we harnessed atomic structures of patient-derived cardiac amyloids determined using cryogenic electron microscopy since 2019. These structures help explain why most but not all ATTR deposits uptake 99mTc-PYP/DPD/HMDP radiotracers, while in AL the opposite is true. Moreover, fibril structures help explain greater microcalcification observed in ATTR vs. AL deposits. These findings may aid the diagnostics and therapeutic targeting of cardiac amyloidosis and are relevant to other amyloids.
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Affiliation(s)
- Emily Lewkowicz
- Department of Pharmacology, Physiology & Biophysics, Boston University Chobanian and Avedisian School of Medicine, Boston, MA, USA.
| | - Shobini Jayaraman
- Department of Pharmacology, Physiology & Biophysics, Boston University Chobanian and Avedisian School of Medicine, Boston, MA, USA.
| | - Olga Gursky
- Department of Pharmacology, Physiology & Biophysics, Boston University Chobanian and Avedisian School of Medicine, Boston, MA, USA.
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Caobelli F, Gözlügöl N, Bakula A, Rominger A, Schepers R, Stortecky S, Hunziker Munsch L, Dobner S, Gräni C. Prognostic Value of [ 99mTc]Tc-DPD Quantitative SPECT/CT in Patients with Suspected and Confirmed Amyloid Transthyretin-Related Cardiomyopathy and Preserved Left Ventricular Function. J Nucl Med 2024; 65:944-951. [PMID: 38724281 DOI: 10.2967/jnumed.123.266926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 04/03/2024] [Indexed: 06/05/2024] Open
Abstract
Quantitative 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid ([99mTc]Tc-DPD) SPECT may be used for risk-stratifying patients with amyloid transthyretin-related cardiomyopathy (ATTR-CM). We aimed to analyze the predictive value of quantitative [99mTc]Tc-DPD SPECT/CT in suspected and confirmed ATTR-CM according to different disease stages. Methods: The study enrolled consecutive patients with suspected ATTR-CM who were referred to a single tertiary center and underwent quantitative [99mTc]Tc-DPD SPECT/CT allowing SUVmax and SUVpeak analysis. Patients were divided into 2 groups according to left ventricular ejection fraction (LVEF) at baseline (i.e., ≥50% and <50%). Clinical, laboratory, and echocardiographic parameters and major adverse cardiac events (i.e., all-cause death, sustained ventricular tachyarrhythmia, hospitalization for heart failure, implantation of a cardioverter defibrillator) were investigated for any correlation with quantitative uptake values. Results: In total, 144 patients with suspected ATTR-CM were included in the study (98 with LVEF ≥ 50% and 46 with LVEF < 50%), of whom 99 were diagnosed with ATTR-CM (68.8%; 69 with LVEF ≥ 50% and 30 with LVEF < 50%). A myocardial SUVmax of at least 7 was predictive of major adverse cardiac events at 21.9 ± 13.0 mo of follow-up (hazard ratio, 2.875; 95% CI, 1.23-6.71; P = 0.015) in patients with suspected or confirmed ATTR-CM (global χ2 = 6.892, P = 0.02) and an LVEF of at least 50%. SUVmax was not predictive in patients with an LVEF of less than 50% and suspected or confirmed ATTR-CM. Conclusion: In patients with suspected or confirmed ATTR-CM and preserved LVEF, representing an early disease stage, quantitative [99mTc]Tc-DPD SPECT should be considered to improve early-stage risk stratification.
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Affiliation(s)
- Federico Caobelli
- Department of Nuclear Medicine, Bern University Hospital, University of Bern, Bern, Switzerland;
| | - Nasir Gözlügöl
- Department of Nuclear Medicine, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Adam Bakula
- Department of Nuclear Medicine, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Axel Rominger
- Department of Nuclear Medicine, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Robin Schepers
- Department of Nuclear Medicine, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Stefan Stortecky
- Department of Cardiology, Bern University Hospital, University of Bern, Bern, Switzerland; and
| | - Lukas Hunziker Munsch
- Department of Cardiology, Bern University Hospital, University of Bern, Bern, Switzerland; and
| | - Stephan Dobner
- Department of Cardiology, Bern University Hospital, University of Bern, Bern, Switzerland; and
- Third Medical Department of Cardiology and Intensive Care Medicine, Clinic Ottakring, Vienna, Austria
| | - Christoph Gräni
- Department of Cardiology, Bern University Hospital, University of Bern, Bern, Switzerland; and
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Rischpler C, Kersting D, Kessler L, Varasteh Z, Luedike P, Carpinteiro A, Rassaf T, Herrmann K, Papathanasiou M. Reply: Recent Evidence on Cardiac 99mTc-DPD Uptake After Therapy with Tafamidis May Reveal the Road to an Ultra-Early Diagnosis in Patients with ATTR Amyloidosis. J Nucl Med 2024; 65:330. [PMID: 38212071 DOI: 10.2967/jnumed.123.266767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 12/06/2023] [Accepted: 12/12/2023] [Indexed: 01/13/2024] Open
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Gheysens O, Treglia G, Masri A, Hyafil F, Dorbala S. Treatment response assessment in transthyretin-related cardiac amyloidosis: an emerging clinical indication of bone-seeking radiopharmaceuticals? Eur J Nucl Med Mol Imaging 2024; 51:691-694. [PMID: 38110712 DOI: 10.1007/s00259-023-06576-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Affiliation(s)
- Olivier Gheysens
- Department of Nuclear Medicine, Cliniques Universitaires Saint-Luc and Institute for Experimental and Clinical Research (IREC), Université Catholique de Louvain, Avenue Hippocrate 10, 1200, Brussels, Belgium.
| | - Giorgio Treglia
- Division of Nuclear Medicine, Imaging Institute of Southern Switzerland, Ente Ospedaliero Cantonale, Bellinzona, Switzerland
- Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- Faculty of Biomedical Sciences, Università della Svizzera italiana, Lugano, Switzerland
| | - Ahmad Masri
- Amyloidosis Center, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Fabien Hyafil
- Department of Nuclear Medicine, AP-HP, European Hospital Georges Pompidou, University of Paris-Cité, Paris, France
| | - Sharmila Dorbala
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
- Cardiac Amyloidosis Program, Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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