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Pazderová L, Benešová M, Havlíčková J, Vojtíčková M, Kotek J, Lubal P, Ullrich M, Walther M, Schulze S, Neuber C, Rammelt S, Pietzsch HJ, Pietzsch J, Kubíček V, Hermann P. Cyclam with a phosphinate-bis(phosphonate) pendant arm is a bone-targeting carrier of copper radionuclides. Dalton Trans 2022; 51:9541-9555. [PMID: 35670322 DOI: 10.1039/d2dt01172g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ligands combining a bis(phosphonate) group with a macrocycle function as metal isotope carriers for radionuclide-based imaging and for treating bone metastases associated with several cancers. However, bis(phosphonate) pendant arms often slow down complex formation and decrease radiochemical yields. Nevertheless, their negative effect on complexation rates may be mitigated by using a suitable spacer between bis(phosphonate) and the macrocycle. To demonstrate the potential of bis(phosphonate) bearing macrocyclic ligands as a copper radioisotope carrier, we report the synthesis of a new cyclam derivative bearing a phosphinate-bis(phosphonate) pendant (H5te1PBP). The ligand showed a high selectivity to CuII over ZnII and NiII ions, and the bis(phosphonate) group was not coordinated in the CuII complex, strongly interacting with other metal ions in solution. The CuII complex formed quickly, in 1 s, at pH 5 and at a millimolar scale. The complexation rates significantly differed under a ligand or metal ion excess due to the formation of reaction intermediates differing in their metal-to-ligand ratio and protonation state, respectively. The CuII-te1PBP complex also showed a high resistance to acid-assisted hydrolysis (t1/2 2.7 h; 1 M HClO4, 25 °C) and was effectively adsorbed on the hydroxyapatite surface. H5te1PBP radiolabeling with [64Cu]CuCl2 was fast and efficient, with specific activities of approximately 30 GBq 64Cu per 1 μmol of ligand (pH 5.5, room temperature, 30 min). In a pilot experiment, we further demonstrated the excellent suitability of [64Cu]CuII-te1PBP for imaging active bone compartments by dedicated small animal PET/CT in healthy mice and subsequently in a rat femoral defect model, in direct comparison with [18F]fluoride. Moreover, [64Cu]CuII-te1PBP showed a higher uptake in critical bone defect regions. Therefore, our study highlights the potential of [64Cu]CuII-te1PBP as a PET radiotracer for evaluating bone healing in preclinical and clinical settings with a diagnostic value similar to that of [18F]fluoride, albeit with a longer half-life (12.7 h) than 18F (1.8 h), thereby enabling extended observation times.
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Affiliation(s)
- Lucia Pazderová
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 40 Prague 2, Czech Republic.
| | - Martina Benešová
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 40 Prague 2, Czech Republic. .,Research Group Molecular Biology of Systemic Radiotherapy, German Cancer Research Center, Im Neuenheimer Feld 223, 69120 Heidelberg, Germany
| | - Jana Havlíčková
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 40 Prague 2, Czech Republic.
| | - Margareta Vojtíčková
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 40 Prague 2, Czech Republic.
| | - Jan Kotek
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 40 Prague 2, Czech Republic.
| | - Přemysl Lubal
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Martin Ullrich
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstrasse 400, 01328 Dresden, Germany
| | - Martin Walther
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstrasse 400, 01328 Dresden, Germany
| | - Sabine Schulze
- Technische Universität Dresden, Faculty of Medicine, Centre for Translational Bone, Joint and Soft Tissue Research, Fetscherstrasse 74, 01307 Dresden, Germany
| | - Christin Neuber
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstrasse 400, 01328 Dresden, Germany
| | - Stefan Rammelt
- Technische Universität Dresden, University Hospital Carl Gustav Carus, University Center for Orthopaedics and Traumatology, Fetscherstrasse 74, 01307 Dresden, Germany
| | - Hans-Jürgen Pietzsch
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstrasse 400, 01328 Dresden, Germany.,Technische Universität Dresden, School of Science, Faculty of Chemistry and Food Chemistry, 01069 Dresden, Germany
| | - Jens Pietzsch
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstrasse 400, 01328 Dresden, Germany.,Technische Universität Dresden, School of Science, Faculty of Chemistry and Food Chemistry, 01069 Dresden, Germany
| | - Vojtěch Kubíček
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 40 Prague 2, Czech Republic.
| | - Petr Hermann
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 40 Prague 2, Czech Republic.
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Miller ADC, Ozbakir HF, Mukherjee A. Calcium-responsive contrast agents for functional magnetic resonance imaging. ACTA ACUST UNITED AC 2021; 2:021301. [PMID: 34085055 DOI: 10.1063/5.0041394] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/15/2021] [Indexed: 02/07/2023]
Abstract
Calcium ions represent one of the key second messengers accompanying neural activity and synaptic signaling. Accordingly, dynamic imaging of calcium fluctuations in living organisms represents a cornerstone technology for discovering neural mechanisms that underlie memory, determine behavior, and modulate emotional states as well as how these mechanisms are perturbed by neurological disease and brain injury. While optical technologies are well established for high resolution imaging of calcium dynamics, physical limits on light penetration hinder their application for whole-brain imaging in intact vertebrates. Unlike optics, magnetic resonance imaging (MRI) enables noninvasive large-scale imaging across vertebrates of all sizes. This has motivated the development of several sensors that leverage innovative physicochemical mechanisms to sensitize MRI contrast to intracellular and extracellular changes in calcium. Here, we review the current state-of-the-art in MRI-based calcium sensors, focusing on fundamental aspects of sensor performance, in vivo applications, and challenges related to sensitivity. We also highlight how innovations at the intersection of reporter gene technology and gene delivery open potential opportunities for mapping calcium activity in genetically targeted cells, complementing the benefits of small molecule probes and nanoparticle sensors.
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Affiliation(s)
- Austin D C Miller
- Biomolecular Science and Engineering, University of California, Santa Barbara, California 93106, USA
| | - Harun F Ozbakir
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA
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Kuźnik A, Październiok-Holewa A, Jewula P, Kuźnik N. Bisphosphonates-much more than only drugs for bone diseases. Eur J Pharmacol 2019; 866:172773. [PMID: 31705903 DOI: 10.1016/j.ejphar.2019.172773] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 10/23/2019] [Accepted: 11/01/2019] [Indexed: 12/22/2022]
Abstract
α,α-Bisphosphonates (BPs) are well established in the treatment of bone diseases such as osteoporosis and Paget's disease. Their successful application originates from their high affinity to hydroxyapatite. While the initially appreciated features of BPs are already beneficial to many patients, recent developments have further expanded their pleiotropic applications. This review describes the background of the interactions of BPs with bone cells that form the basis of the classical treatment. A better understanding of the mechanism behind their interactions allows for the parallel application of BPs against bone cancer and metastases followed by palliative pain relief. Targeted therapy with bone-seeking BPs coupled with a diagnostic agent in one particle resulted in theranostics which is also described here. For example, in such a system, BP moieties are bound to contrast agents used in magnetic resonance imaging or radionuclides used in positron emission tomography. In addition, another example of the pleiotropic function of BPs which involves targeting the imaging agents to bone tissues accompanied by pain reduction is presented in this work.
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Affiliation(s)
- Anna Kuźnik
- Department of Organic and Bioorganic Chemistry and Biotechnology, Silesian University of Technology, B. Krzywoustego 4, 44-100, Gliwice, Poland; Biotechnology Center of Silesian University of Technology, B. Krzywoustego 8, 44-100, Gliwice, Poland.
| | - Agnieszka Październiok-Holewa
- Department of Organic and Bioorganic Chemistry and Biotechnology, Silesian University of Technology, B. Krzywoustego 4, 44-100, Gliwice, Poland; Biotechnology Center of Silesian University of Technology, B. Krzywoustego 8, 44-100, Gliwice, Poland
| | - Pawel Jewula
- Central European Institute of Technology, Brno University of Technology, Purkyňova 656/123, 612-00, Brno, Czech Republic
| | - Nikodem Kuźnik
- Department of Organic and Bioorganic Chemistry and Biotechnology, Silesian University of Technology, B. Krzywoustego 4, 44-100, Gliwice, Poland
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Abstract
Many elegant inorganic designs have been developed to aid medical imaging. We know better now how to improve imaging due to the enormous efforts made by scientists in probe design and other fundamental sciences, including inorganic chemistry, physiochemistry, analytical chemistry, and biomedical engineering. However, despite several years being invested in the development of diagnostic probes, only a few examples have shown applicability in MRI in vivo. In this short review, we aim to show the reader the latest advances in the application of inorganic agents in preclinical MRI.
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Wahsner J, Gale EM, Rodríguez-Rodríguez A, Caravan P. Chemistry of MRI Contrast Agents: Current Challenges and New Frontiers. Chem Rev 2019; 119:957-1057. [PMID: 30350585 PMCID: PMC6516866 DOI: 10.1021/acs.chemrev.8b00363] [Citation(s) in RCA: 843] [Impact Index Per Article: 168.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Tens of millions of contrast-enhanced magnetic resonance imaging (MRI) exams are performed annually around the world. The contrast agents, which improve diagnostic accuracy, are almost exclusively small, hydrophilic gadolinium(III) based chelates. In recent years concerns have arisen surrounding the long-term safety of these compounds, and this has spurred research into alternatives. There has also been a push to develop new molecularly targeted contrast agents or agents that can sense pathological changes in the local environment. This comprehensive review describes the state of the art of clinically approved contrast agents, their mechanism of action, and factors influencing their safety. From there we describe different mechanisms of generating MR image contrast such as relaxation, chemical exchange saturation transfer, and direct detection and the types of molecules that are effective for these purposes. Next we describe efforts to make safer contrast agents either by increasing relaxivity, increasing resistance to metal ion release, or by moving to gadolinium(III)-free alternatives. Finally we survey approaches to make contrast agents more specific for pathology either by direct biochemical targeting or by the design of responsive or activatable contrast agents.
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Affiliation(s)
- Jessica Wahsner
- Athinoula A. Martinos Center for Biomedical Imaging and the Institute for Innovation in Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Eric M. Gale
- Athinoula A. Martinos Center for Biomedical Imaging and the Institute for Innovation in Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Aurora Rodríguez-Rodríguez
- Athinoula A. Martinos Center for Biomedical Imaging and the Institute for Innovation in Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Peter Caravan
- Athinoula A. Martinos Center for Biomedical Imaging and the Institute for Innovation in Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
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Procházková S, Hraníček J, Kubíček V, Hermann P. Formation kinetics of europium(III) complexes of DOTA and its bis(phosphonate) bearing analogs. Polyhedron 2016. [DOI: 10.1016/j.poly.2016.03.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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7
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Hingorani DV, Bernstein AS, Pagel MD. A review of responsive MRI contrast agents: 2005-2014. CONTRAST MEDIA & MOLECULAR IMAGING 2015; 10:245-65. [PMID: 25355685 PMCID: PMC4414668 DOI: 10.1002/cmmi.1629] [Citation(s) in RCA: 140] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 09/06/2014] [Accepted: 09/18/2014] [Indexed: 12/18/2022]
Abstract
This review focuses on MRI contrast agents that are responsive to a change in a physiological biomarker. The response mechanisms are dependent on six physicochemical characteristics, including the accessibility of water to the agent, tumbling time, proton exchange rate, electron spin state, MR frequency or superparamagnetism of the agent. These characteristics can be affected by changes in concentrations or activities of enzymes, proteins, nucleic acids, metabolites, or metal ions, or changes in redox state, pH, temperature, or light. A total of 117 examples are presented, including ones that employ nuclei other than (1) H, which attests to the creativity of multidisciplinary research efforts to develop responsive MRI contrast agents.
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Affiliation(s)
- Dina V Hingorani
- Department of Chemistry and Biochemistry, University of Arizona, USA
| | - Adam S Bernstein
- Department of Biomedical Engineering, University of Arizona, USA
| | - Mark D Pagel
- Department of Chemistry and Biochemistry, University of Arizona, USA
- Department of Biomedical Engineering, University of Arizona, USA
- Department of Medical Imaging, University of Arizona, USA
- University of Arizona Cancer Center, University of Arizona, USA
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Hagberg GE, Mamedov I, Power A, Beyerlein M, Merkle H, Kiselev VG, Dhingra K, Kubìček V, Angelovski G, Logothetis NK. Diffusion properties of conventional and calcium-sensitive MRI contrast agents in the rat cerebral cortex. CONTRAST MEDIA & MOLECULAR IMAGING 2014; 9:71-82. [PMID: 24470296 DOI: 10.1002/cmmi.1535] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 11/22/2012] [Accepted: 01/15/2013] [Indexed: 01/01/2023]
Abstract
Calcium-sensitive MRI contrast agents can only yield quantitative results if the agent concentration in the tissue is known. The agent concentration could be determined by diffusion modeling, if relevant parameters were available. We have established an MRI-based method capable of determining diffusion properties of conventional and calcium-sensitive agents. Simulations and experiments demonstrate that the method is applicable both for conventional contrast agents with a fixed relaxivity value and for calcium-sensitive contrast agents. The full pharmacokinetic time-course of gadolinium concentration estimates was observed by MRI before, during and after intracerebral administration of the agent, and the effective diffusion coefficient D* was determined by voxel-wise fitting of the solution to the diffusion equation. The method yielded whole brain coverage with a high spatial and temporal sampling. The use of two types of MRI sequences for sampling of the diffusion time courses was investigated: Look-Locker-based quantitative T(1) mapping, and T(1) -weighted MRI. The observation times of the proposed MRI method is long (up to 20 h) and consequently the diffusion distances covered are also long (2-4 mm). Despite this difference, the D* values in vivo were in agreement with previous findings using optical measurement techniques, based on observation times of a few minutes. The effective diffusion coefficient determined for the calcium-sensitive contrast agents may be used to determine local tissue concentrations and to design infusion protocols that maintain the agent concentration at a steady state, thereby enabling quantitative sensing of the local calcium concentration.
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Affiliation(s)
- Gisela E Hagberg
- Department for Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
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9
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Affiliation(s)
- Marie C. Heffern
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, Evanston, Illinois 60208-3113
| | - Lauren M. Matosziuk
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, Evanston, Illinois 60208-3113
| | - Thomas J. Meade
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, Evanston, Illinois 60208-3113
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Abstract
Biomedical imaging techniques can provide a vast amount of anatomical information, enabling diagnosis and the monitoring of disease and treatment profile. MRI uniquely offers convenient, non-invasive, high resolution tomographic imaging. A considerable amount of effort has been invested, across several decades, in the design of non toxic paramagnetic contrast agents capable of enhancing positive MRI signal contrast. Recently, focus has shifted towards the development of agents capable of specifically reporting on their local biochemical environment, where a switch in image contrast is triggered by a specific stimulus/biochemical variable. Such an ability would not only strengthen diagnosis but also provide unique disease-specific biochemical insight. This feature article focuses on recent progress in the development of MRI contrast switching with molecular, macromolecular and nanoparticle-based agents.
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Affiliation(s)
- Gemma-Louise Davies
- Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK.
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11
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Tu C, Louie AY. Strategies for the development of gadolinium-based 'q'-activatable MRI contrast agents. NMR IN BIOMEDICINE 2013; 26:781-787. [PMID: 23015370 PMCID: PMC3586386 DOI: 10.1002/nbm.2870] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 06/26/2012] [Accepted: 08/24/2012] [Indexed: 06/01/2023]
Abstract
The emergence and rapid development of activatable contrast agents (CAs), whose relaxivity changes in response to the variation of a specific marker in the surrounding physiological microenvironment, have expanded the scope of MRI beyond anatomical and functional imaging to also convey information at the cellular and molecular level. The essence of an activatable MRI CA is the difference in relaxivity before and after a change in a physiological variable: the larger the difference, the better the CA. In this review, strategies for the design of activatable gadolinium CAs, with a switching mechanism based on the modulation of hydration (q), sensitive to common variables in the physiological microenvironment, such as pH, light, redox and metal ions, are illustrated and discussed.
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12
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Promising strategies for Gd-based responsive magnetic resonance imaging contrast agents. Curr Opin Chem Biol 2012; 17:158-66. [PMID: 23141598 DOI: 10.1016/j.cbpa.2012.10.031] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 10/18/2012] [Accepted: 10/20/2012] [Indexed: 11/22/2022]
Abstract
Magnetic resonance imaging is a powerful imaging modality that is often coupled with paramagnetic contrast agents based on gadolinium to enhance sensitivity and image quality. Responsive contrast agents are key to furthering the diagnostic potential of MRI, both to provide anatomical information and to discern biochemical activity. Recent design of responsive gadolinium-based T₁ agents has made interesting progress, with the development of novel complexes which sense their chemical environment through changes in the coordination of water molecules, the molecular tumbling time or the number of metal centres. Particular promising design strategies include the use of multimeric systems, and the development of dual imaging probes.
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Abada S, Lecointre A, Elhabiri M, Esteban-Gómez D, Platas-Iglesias C, Tallec G, Mazzanti M, Charbonnière LJ. Highly relaxing gadolinium based MRI contrast agents responsive to Mg2+ sensing. Chem Commun (Camb) 2012; 48:4085-7. [PMID: 22430859 DOI: 10.1039/c2cc30757j] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A Gd complex based on a polyphosphonated pyridyl ligand shows a very high stability in aqueous solution (log K(EuL) = 25.7), a high relaxivity (8.5 mM(-1) s(-1) at 25 °C and 20 MHz) and a marked and selective relaxivity enhancement (37%) in the presence of Mg(2+), opening interesting perspectives for the design of cation responsive contrast agents.
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Affiliation(s)
- Sabah Abada
- Laboratoire d'Ingénierie Moléculaire Appliquée à l'Analyse, IPHC, UMR 7178 CNRS/UdS, ECPM 25 rue Becquerel, 67087 Strasbourg Cedex 2, France
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Is there a path beyond BOLD? Molecular imaging of brain function. Neuroimage 2012; 62:1208-15. [PMID: 22406355 DOI: 10.1016/j.neuroimage.2012.02.076] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 02/18/2012] [Accepted: 02/27/2012] [Indexed: 12/20/2022] Open
Abstract
The dependence of BOLD on neuro-vascular coupling leaves it many biological steps removed from direct monitoring of neural function. MRI based approaches have been developed aimed at reporting more directly on brain function. These include: manganese enhanced MRI as a surrogate for calcium ion influx; agents responsive to calcium concentrations; approaches to measure membrane potential; agents to measure neurotransmitters; and strategies to measure gene expression. This work has led to clever design of molecular imaging tools and many contributions to studies of brain function in animal models. However, a robust approach that has potential to get MRI closer to neurons in the human brain has not yet emerged.
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Řehoř I, Vilímová V, Jendelová P, Kubíček V, Jirák D, Herynek V, Kapcalová M, Kotek J, Černý J, Hermann P, Lukeš I. Phosphonate–Titanium Dioxide Assemblies: Platform for Multimodal Diagnostic–Therapeutic Nanoprobes. J Med Chem 2011; 54:5185-94. [DOI: 10.1021/jm200449y] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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Henig J, Mamedov I, Fouskova P, Tóth É, Logothetis NK, Angelovski G, Mayer HA. Influence of Calcium-Induced Aggregation on the Sensitivity of Aminobis(methylenephosphonate)-Containing Potential MRI Contrast Agents. Inorg Chem 2011; 50:6472-81. [DOI: 10.1021/ic1024235] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jörg Henig
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Ilgar Mamedov
- Abteilung für Physiologie kognitiver Prozesse, Max-Planck-Institut für biologische Kybernetik, Spemannstrasse 38, 72076 Tübingen, Germany
| | - Petra Fouskova
- Le Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique, CNRS, Rue Charles Sadron, 45071 Orléans, France
| | - Éva Tóth
- Le Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique, CNRS, Rue Charles Sadron, 45071 Orléans, France
| | - Nikos K. Logothetis
- Abteilung für Physiologie kognitiver Prozesse, Max-Planck-Institut für biologische Kybernetik, Spemannstrasse 38, 72076 Tübingen, Germany
- Imaging Science and Biomedical Engineering, The University of Manchester, Oxford Road, Manchester M13 9PT, U.K
| | - Goran Angelovski
- Abteilung für Physiologie kognitiver Prozesse, Max-Planck-Institut für biologische Kybernetik, Spemannstrasse 38, 72076 Tübingen, Germany
| | - Hermann A. Mayer
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
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Tu C, Osborne EA, Louie AY. Activatable T₁ and T₂ magnetic resonance imaging contrast agents. Ann Biomed Eng 2011; 39:1335-48. [PMID: 21331662 PMCID: PMC3069332 DOI: 10.1007/s10439-011-0270-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 02/04/2011] [Indexed: 12/25/2022]
Abstract
Magnetic resonance imaging (MRI) has become one of the most important diagnosis tools available in medicine. Typically MRI is not capable of sensing biochemical activities. However, recently emerged activatable MRI contrast agents (CAs), whose relaxivity is variable in response to a specific parameter change in the surrounding physiological microenvironment, potentially allow for MRI to indicate biological processes. Among the various factors influencing the relaxivity of a CA, the number of inner-sphere water molecules (q) directly coordinated to the metal center, the residence time of the coordinated water molecule (τ (m)), and the rotational correlation time representing the molecular tumbling time of a complex (τ (R)) contribute strongly to the relaxivity of an activatable CA. Tuning the ligand structure and properties has been the subject of intensive research for activatable MR CA designs. This review summarizes a variety of activatable MRI CAs sensitive to common variables in microenvironment in vivo, i.e., pH, luminescence, metal ions, redox, and enzymes, etc., with emphasis on the influence of ligand design on parameters q, τ (m), and τ (R).
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Affiliation(s)
- Chuqiao Tu
- Department of Biomedical Engineering, University of California, Davis, CA, 95616, USA
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