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Boros E, Karimi S, Kenton N, Helm L, Caravan P. Gd(DOTAlaP): exploring the boundaries of fast water exchange in gadolinium-based magnetic resonance imaging contrast agents. Inorg Chem 2014; 53:6985-94. [PMID: 24922178 PMCID: PMC4095929 DOI: 10.1021/ic5008928] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
![]()
Here,
we describe the synthesis of the single amino acid chelator DOTAlaP
and four of its derivatives. The corresponding gadolinium(III) complexes
were investigated for their kinetic inertness, relaxometric properties
at a range of fields and temperatures, water exchange rate, and interaction
with human serum albumin (HSA). Derivatives with one inner-sphere
water (q = 1) were determined to have a mean water
residency time between 8 and 6 ns in phoshate-buffered saline at 37
°C. The corresponding europium complexes were also formed and
used to obtain information on the hydration number of the corresponding
coordination complexes. Two complexes capable of binding HSA were
also synthesized, of which one, Gd(5b), contains no inner-sphere
water, while the other derivative, Gd(4b), is a mixture
of ca. 15% q =1 and 85% q = 0. In
the presence of HSA, the latter displayed a very short mean water
residency time (τM310 = 2.4 ns) and enhanced
relaxivity at intermediate and high fields. The kinetic inertness
of Gd(4b) with respect to complex dissociation was decreased
compared to its DOTAla analogue but still 100-fold more inert than
[Gd(BOPTA)(H2O)]2–. Magnetic resonance
imaging in mice showed that Gd(4b) was able to provide
38% better vessel to muscle contrast compared to the clinically used
HSA binding agent MS-325. Converting one
of the acetate groups in the single amino acid chelator DOTAla to
methylenephosphonate (DOTAlaP) results in gadolinium(III) complexes
with extremely fast water exchange kinetics and/or in equilibrium
between monoaquated (q = 1) and unaquated (q = 0) states. The presence of phosphonate and the very
fast water exchange kinetics result in stable complexes with high
relaxivity at high magnetic fields, especially when bound to serum
albumin.
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Affiliation(s)
- Eszter Boros
- The Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School , 149 Thirteenth Street, Suite 2301, Charlestown, Massachusetts 02129, United States
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52
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Alhadad A, Åkesson M, Lehti L, Leander P, Sterner G, Åkeson P, Wassélius J. Safety aspects of gadofosveset in clinical practice – analysis of acute and long-term complications. Magn Reson Imaging 2014; 32:570-3. [DOI: 10.1016/j.mri.2014.02.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 02/06/2014] [Accepted: 02/06/2014] [Indexed: 11/25/2022]
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53
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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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54
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Xue S, Qiao J, Jiang J, Hubbard K, White N, Wei L, Li S, Liu ZR, Yang JJ. Design of ProCAs (protein-based Gd(3+) MRI contrast agents) with high dose efficiency and capability for molecular imaging of cancer biomarkers. Med Res Rev 2014; 34:1070-99. [PMID: 24615853 DOI: 10.1002/med.21313] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Magnetic resonance imaging (MRI) is the leading imaging technique for disease diagnostics, providing high resolution, three-dimensional images noninvasively. MRI contrast agents are designed to improve the contrast and sensitivity of MRI. However, current clinically used MRI contrast agents have relaxivities far below the theoretical upper limit, which largely prevent advancing molecular imaging of biomarkers with desired sensitivity and specificity. This review describes current progress in the development of a new class of protein-based MRI contrast agents (ProCAs) with high relaxivity using protein design to optimize the parameters that govern relaxivity. Further, engineering with targeting moiety allows these contrast agents to be applicable for molecular imaging of prostate cancer biomarkers by MRI. The developed protein-based contrast agents also exhibit additional in vitro and in vivo advantages for molecular imaging of disease biomarkers, such as high metal-binding stability and selectivity, reduced toxicity, proper blood circulation time, and higher permeability in tumor tissue in addition to improved relaxivities.
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Affiliation(s)
- Shenghui Xue
- Departments of Chemistry and Biology, Georgia State University, Atlanta, Georgia; Center for Diagnostics & Therapeutics (CDT), Georgia State University, Atlanta, Georgia; Center for Biotechnology and Drug Design, Georgia State University, Atlanta, Georgia
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55
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Debroye E, Parac-Vogt TN. Towards polymetallic lanthanide complexes as dual contrast agents for magnetic resonance and optical imaging. Chem Soc Rev 2014; 43:8178-92. [DOI: 10.1039/c4cs00201f] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In the spotlight: polymetallic complexes permitting efficient sensitization of lanthanide luminescence and exhibiting favorable relaxometric properties.
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Affiliation(s)
- Elke Debroye
- Department of Chemistry
- KU Leuven
- 3001 Leuven, Belgium
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56
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Lux J, Chan M, Elst LV, Schopf E, Mahmoud E, Laurent S, Almutairi A. Metal Chelating Crosslinkers Form Nanogels with High Chelation Stability. J Mater Chem B 2013; 1:6359-6364. [PMID: 24505553 PMCID: PMC3910426 DOI: 10.1039/c3tb21104e] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present a series of hydrogel nanoparticles (nanogels) incorporating either acyclic or cyclic metal chelates as crosslinkers. These crosslinkers are used to formulate polyacrylamide-based nanogels (diameter 50 to 85 nm) yielding contrast agents with enhanced relaxivities (up to 6-fold greater than Dotarem®), because this nanogel structure slows the chelator's tumbling frequency and allows fast water exchange. Importantly, these nanogels also stabilize Gd3+ within the chelator thermodynamically and kinetically against metal displacement through transmetallation, which should reduce toxicity associated with release of free Gd3+. This chelation stability suggests that the chelate crosslinker strategy may prove useful for other applications of metal-chelating nanoparticles in medicine, including other imaging modalities and radiotherapy.
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Affiliation(s)
- Jacques Lux
- Skaggs School of Pharmacy and Pharmaceutical Sciences. KACST-UCSD Center of Excellence in Nanomedicine. Laboratory of Bioresponsive Materials, University of California, San Diego. 9500 Gilman Dr., 0600, PSB 2270, La Jolla, CA-92093-0600, United States
| | - Minnie Chan
- Skaggs School of Pharmacy and Pharmaceutical Sciences. KACST-UCSD Center of Excellence in Nanomedicine. Laboratory of Bioresponsive Materials, University of California, San Diego. 9500 Gilman Dr., 0600, PSB 2270, La Jolla, CA-92093-0600, United States
| | - Luce Vander Elst
- Department of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, University of Mons, 7000 Mons, Belgium.Address, Address, Town, Country
| | - Eric Schopf
- Skaggs School of Pharmacy and Pharmaceutical Sciences. KACST-UCSD Center of Excellence in Nanomedicine. Laboratory of Bioresponsive Materials, University of California, San Diego. 9500 Gilman Dr., 0600, PSB 2270, La Jolla, CA-92093-0600, United States
| | - Enas Mahmoud
- Skaggs School of Pharmacy and Pharmaceutical Sciences. KACST-UCSD Center of Excellence in Nanomedicine. Laboratory of Bioresponsive Materials, University of California, San Diego. 9500 Gilman Dr., 0600, PSB 2270, La Jolla, CA-92093-0600, United States
| | - Sophie Laurent
- Department of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, University of Mons, 7000 Mons, Belgium.Address, Address, Town, Country
| | - Adah Almutairi
- Skaggs School of Pharmacy and Pharmaceutical Sciences. KACST-UCSD Center of Excellence in Nanomedicine. Laboratory of Bioresponsive Materials, University of California, San Diego. 9500 Gilman Dr., 0600, PSB 2270, La Jolla, CA-92093-0600, United States
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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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58
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Gale EM, Zhu J, Caravan P. Direct measurement of the Mn(II) hydration state in metal complexes and metalloproteins through 17O NMR line widths. J Am Chem Soc 2013; 135:18600-8. [PMID: 24088013 DOI: 10.1021/ja4094132] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Here we describe a simple method to estimate the inner-sphere hydration state of the Mn(II) ion in coordination complexes and metalloproteins. The line width of bulk H2(17)O is measured in the presence and absence of Mn(II) as a function of temperature, and transverse (17)O relaxivities are calculated. It is demonstrated that the maximum (17)O relaxivity is directly proportional to the number of inner-sphere water ligands (q). Using a combination of literature data and experimental data for 12 Mn(II) complexes, we show that this method provides accurate estimates of q with an uncertainty of ±0.2 water molecules. The method can be implemented on commercial NMR spectrometers working at fields of 7 T and higher. The hydration number can be obtained for micromolar Mn(II) concentrations. We show that the technique can be extended to metalloproteins or complex:protein interactions. For example, Mn(II) binds to the multimetal binding site A on human serum albumin with two inner-sphere water ligands that undergo rapid exchange (1.06 × 10(8) s(-1) at 37 °C). The possibility of extending this technique to other metal ions such as Gd(III) is discussed.
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Affiliation(s)
- Eric M Gale
- The Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital , Harvard Medical School , 149 Thirteenth Street, Suite 2301, Charlestown, Massachusetts 02129, United States
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59
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Yang CT, Chandrasekharan P, He T, Poh Z, Raju A, Chuang KH, Robins EG. An intravascular MRI contrast agent based on Gd(DO3A-Lys) for tumor angiography. Biomaterials 2013; 35:327-36. [PMID: 24138829 DOI: 10.1016/j.biomaterials.2013.10.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 10/01/2013] [Indexed: 02/02/2023]
Abstract
An intravascular MRI contrast agent Gd(DO3A-Lys), Gadolinium(III) (2,2',2″-(10-(3-(5-benzamido-6-methoxy-6-oxohexylamino)-3-oxopropyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetate), has been studied for tumor angiography based on its high relaxivity and long blood half-life. The preparation procedures of the contrast agent have been modified in order to achieve higher yield and improve the synthetic reproducibility. High relaxivity of Gd(DO3A-Lys) has been confirmed by measurements at 3 T, 7 T and 9.4 T magnetic fields. The relaxivity-dependent albumin binding study indicated that Gd(DO3A-Lys) partially bound to albumin protein. In vitro cell viability in HK2 cell indicated low cytotoxicity of Gd(DO3A-Lys) up to 1.2 mM [Gd] concentration. In vivo toxicity studies demonstrated no toxicity of Gd(DO3A-Lys) on kidney tissues up to 0.2 mM [Gd]. While the toxicity on liver tissue was not observed at low dosage (1.0 mM [Gd]), Gd(DO3A-Lys) cause certain damage on hepatic tissue at high dosage (2.0 mM [Gd]). The DO3A-Lys has been labeled with (68)Ga radioisotope for biodistribution studies. (68)Ga(DO3A-Lys) has high uptake in both HT1080 and U87MG xenograft tumors, and has high accumulation in blood. Contrast-enhanced MR angiography (CE-MRA) in mice bearing U87MG xenograft tumor demonstrated that Gd(DO3A-Lys) could enhance vascular microenvironment around the tumor, and displays promising characteristics of an MRI contrast agent for tumor angiography.
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Affiliation(s)
- Chang-Tong Yang
- Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A*STAR), 11 Biopolis Way, #02-02 Helios, Singapore 138667, Singapore.
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60
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Nakajima T, Turkbey B, Sano K, Sato K, Bernardo M, Hoyt RF, Choyke PL, Kobayashi H. MR lymphangiography with intradermal gadofosveset and human serum albumin in mice and primates. J Magn Reson Imaging 2013; 40:691-7. [PMID: 24123370 DOI: 10.1002/jmri.24395] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 08/15/2013] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To investigate MR lymphangiography in mice and primates with intradermal Gadofosveset and human serum albumin. Gadofosveset is a US FDA approved small molecule Gadolinium (Gd) chelate (957 Da) which reversibly binds serum albumin and temporally behaves as a macromolecule. As the structure of albumin varies among species, the affinity of Gadofosveset is optimized for human albumin. In this study, Gadofosveset premixed with 10% human serum albumin (HSA) was injected intradermally in mice and monkeys, and then MR lymphangiography was performed on a 3.0 Tesla clinical scanner. MATERIALS AND METHODS Twenty microliters of each agent was injected intradermally at both sides of the front and back paws using a 30-gauge needle into female athymic nude mice (6-8 weeks old, n = 3 mice in each group). The performance of Gadofosveset-HSA was compared with Gd-labeled dendrimers (G4: 6 nm, G6: 10 nm) or Gd-DTPA. The target-to-muscle ratio (TMR = target signal intensity (SI)/muscle SI) was calculated at each time point. The TMRs were compared with a one-way analysis of variance followed by a Bonferroni multiple comparison test. RESULTS Images taken as early as 2.5 min after intradermal (id) injection depicted enhanced lymph nodes using Gadofosveset-HSA (2.41 ± 0.20). Up to 7.5 min after injection, TMRs of Gadofosveset-HSA were greater than those of dendrimers (G4 or G6-Gd-DTPA: 2.24 ± 0.10, 2.12 ± 0.11, respectively). By 15 min postinjection, TMRs of Gadofosveset-HSA (2.18 ± 0.19) were comparable to Gd-labeled dendrimers (G4-Gd-DTPA: 2.37 ± 0.15, G6-Gd-DTPA: 2.25 ± 0.18). Gadofosveset-HSA and Gd labeled dendrimers resulted in satisfactory MR lymphography in mice and monkeys. CONCLUSION Because both Gadofosveset and HSA are approved for human use and Gadofosveset clears rapidly through the kidneys, this method has advantages over Gd-dendrimers and could be used for visualizing lymphatic drainage and detecting lymph nodes.
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61
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Gambino G, De Pinto S, Tei L, Cassino C, Arena F, Gianolio E, Botta M. A new ditopic Gd(III) complex functionalized with an adamantyl moiety as a versatile building block for the preparation of supramolecular assemblies. J Biol Inorg Chem 2013; 19:133-43. [PMID: 24100595 DOI: 10.1007/s00775-013-1050-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 09/24/2013] [Indexed: 10/26/2022]
Abstract
A dimeric GdAAZTA-like complex (AAZTA is 6-amino-6-methylperhydro-1,4-diazepinetetraacetic acid) bearing an adamantyl group (Gd2L1) able to form strong supramolecular adducts with specific hosts such as β-cyclodextrin (β-CD), poly-β-CD, and human serum albumin (HSA) is reported. The relaxometric properties of Gd2L1 were investigated in aqueous solution by measuring the (1)H relaxivity as a function of pH, temperature, and magnetic field strength. The relaxivity of Gd2L1 (per Gd atom) at 40 MHz and 298 K is 17.6 mM(-1) s(-1), a value that remains almost constant at higher fields owing to the great compactness and rigidity of the bimetallic chelate, resulting in an ideal value for the rotational correlation time for high-field MRI applications (1.5-3.0 T). The noncovalent interaction of Gd2L1 with β-CD, poly-β-CD, and HSA and the relaxometric properties of the resulting host-guest adducts were investigated using (1)H relaxometric methods. Relaxivity enhancements of 29 and 108 % were found for Gd2L1-β-CD and Gd2L1-poly-β-CD, respectively. Binding of Gd2L1 to HSA (KA = 1.2 × 10(4) M(-1)) results in a remarkable relaxivity of 41.4 mM(-1) s(-1) for the bound form (+248 %). The relaxivity is only limited by the local rotation of the complex within the binding site, which decreases on passing from Gd2L1-β-CD to Gd2L1-HSA. Finally, the applicability of Gd2L1 as tumor-targeting agent through passive accumulation of the HSA-bound adduct was evaluated via acquisition of magnetic resonance images at 1 T of B16-tumor-bearing mice. These experiments indicate a considerable signal enhancement (+160 %) in tumor after 60 min from the injection and a very low hepatic accumulation.
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Affiliation(s)
- Giuseppe Gambino
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale "Amedeo Avogadro", Viale T. Michel 11, 15121, Alessandria, Italy
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Gale EM, Kenton N, Caravan P. [Gd(CyPic3A)(H2O)2]-: a stable, bis(aquated) and high-relaxivity Gd(III) complex. Chem Commun (Camb) 2013; 49:8060-2. [PMID: 23903523 PMCID: PMC3791611 DOI: 10.1039/c3cc44116d] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We report the synthesis and MR relevant properties of CyPic3A, a heptadentate chelator that forms ternary Gd(III) complexes of hydration state q = 2. [Gd(CyPic3A)(H2O)2](-) affords an r1 value of 5.70 mM(-1) s(-1) at 1.41 T and 310 K and displays thermodynamic stability and kinetic inertness comparable to FDA approved MR imaging probes.
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Affiliation(s)
- Eric M Gale
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
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63
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Dynamic aggregation of the mid-sized gadolinium complex {Ph4[Gd(DTTA)(H2O)2]− 3}. J Biol Inorg Chem 2013; 19:145-59. [DOI: 10.1007/s00775-013-1036-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 08/14/2013] [Indexed: 12/28/2022]
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64
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Eggenspiller A, Michelin C, Desbois N, Richard P, Barbe JM, Denat F, Licona C, Gaiddon C, Sayeh A, Choquet P, Gros CP. Design of Porphyrin-dota-Like Scaffolds as All-in-One Multimodal Heterometallic Complexes for Medical Imaging. European J Org Chem 2013. [DOI: 10.1002/ejoc.201300678] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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65
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Hung AH, Duch MC, Parigi G, Rotz MW, Manus LM, Mastarone DJ, Dam KT, Gits CC, MacRenaris KW, Luchinat C, Hersam MC, Meade TJ. Mechanisms of Gadographene-Mediated Proton Spin Relaxation. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2013; 117:10.1021/jp406909b. [PMID: 24298299 PMCID: PMC3843495 DOI: 10.1021/jp406909b] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Gd(III) associated with carbon nanomaterials relaxes water proton spins at an effectiveness that approaches or exceeds the theoretical limit for a single bound water molecule. These Gd(III)-labeled materials represent a potential breakthrough in sensitivity for Gd(III)-based contrast agents used for magnetic resonance imaging (MRI). However, their mechanism of action remains unclear. A gadographene library encompassing GdCl3, two different Gd(III)-complexes, graphene oxide (GO), and graphene suspended by two different surfactants and subjected to varying degrees of sonication was prepared and characterized for their relaxometric properties. Gadographene was found to perform comparably to other Gd(III)-carbon nanomaterials; its longitudinal (r1) and transverse (r2) relaxivity is modulated between 12-85 mM-1s-1 and 24-115 mM-1s-1, respectively, depending on the Gd(III)-carbon backbone combination. The unusually large relaxivity and its variance can be understood under the modified Florence model incorporating the Lipari-Szabo approach. Changes in hydration number (q), water residence time (τM), molecular tumbling rate (τR), and local motion (τfast) sufficiently explain most of the measured relaxivities. Furthermore, results implicated the coupling between graphene and Gd(III) as a minor contributor to proton spin relaxation.
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Affiliation(s)
- Andy H. Hung
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Matthew C. Duch
- Department of Materials Science and Engineering and Department of Chemistry, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208-3108, United States
| | - Giacomo Parigi
- CERM and Department of Chemistry, University of Florence, via L. Sacconi 6, 50019 Sesto Florence, Italy
| | - Matthew W. Rotz
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Lisa M. Manus
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Daniel J. Mastarone
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Kevin T. Dam
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Colton C. Gits
- Department of Materials Science and Engineering and Department of Chemistry, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208-3108, United States
| | - Keith W. MacRenaris
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Claudio Luchinat
- CERM and Department of Chemistry, University of Florence, via L. Sacconi 6, 50019 Sesto Florence, Italy
| | - Mark C. Hersam
- Department of Materials Science and Engineering and Department of Chemistry, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208-3108, United States
| | - Thomas J. Meade
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
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66
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Pais A, Biton IE, Margalit R, Degani H. Characterization of estrogen-receptor-targeted contrast agents in solution, breast cancer cells, and tumors in vivo. Magn Reson Med 2013; 70:193-206. [PMID: 22887470 PMCID: PMC4547469 DOI: 10.1002/mrm.24442] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 06/10/2012] [Accepted: 07/05/2012] [Indexed: 12/27/2022]
Abstract
The estrogen receptor (ER) is a major prognostic biomarker of breast cancer, currently determined in surgical specimens by immunohistochemistry. Two new ER-targeted probes, pyridine-tetra-acetate-Gd chelate (PTA-Gd) conjugated either to 17β-estradiol (EPTA-Gd) or to tamoxifen (TPTA-Gd), were explored as contrast agents for molecular imaging of ER. In solution, both probes exhibited a micromolar ER binding affinity, fast water exchange rate (∼10(7) s(-1)), and water proton-relaxivity of 4.7-6.8 mM(-1) s(-1). In human breast cancer cells, both probes acted as estrogen agonists and enhanced the water protons T1 relaxation rate and relaxivity in ER-positive as compared to ER-negative cells, with EPTA-Gd showing a higher ER-specific relaxivity than TPTA-Gd. In studies of breast cancer tumors in vivo, EPTA-Gd induced the highest enhancement in ER-positive tumors as compared to ER-negative tumors and muscle tissue, enabling in vivo detection of ER. TPTA-Gd demonstrated the highest enhancement in muscle tissue indicating nonspecific interaction of this agent with muscle components. The extracellular contrast agents, PTA-Gd and GdDTPA, showed no difference in the perfusion capacity of ER-positive and -negative tumors confirming the specific interaction of EPTA-Gd with ER. These findings lay a basis for the molecular imaging of the ER using EPTA-Gd as a template for further developments.
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Affiliation(s)
- Adi Pais
- Department of Biological Regulation, Weizmann Institute of
Science, Rehovot, Israel
| | - Inbal Eti Biton
- Department of Veterinary Resources, Weizmann Institute of
Science, Rehovot, Israel
| | - Raanan Margalit
- Department of Biological Regulation, Weizmann Institute of
Science, Rehovot, Israel
| | - Hadassa Degani
- Department of Biological Regulation, Weizmann Institute of
Science, Rehovot, Israel
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67
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Cheng W, Ping Y, Zhang Y, Chuang KH, Liu Y. Magnetic resonance imaging (MRI) contrast agents for tumor diagnosis. JOURNAL OF HEALTHCARE ENGINEERING 2013; 4:23-45. [PMID: 23502248 DOI: 10.1260/2040-2295.4.1.23] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
This review focuses on MRI contrast agents for tumor diagnosis. Several types of low molecular weight Gd3+-based complexes and dextran-coated superparamagnetic iron oxide (SPIO) nanoparticles have been used for clinical tumor diagnosis as longitudinal relaxation time (T1) and transverse relaxation time (T2) MRI contrast agents, respectively. To further improve the sensitivity of MRI, new types of chelates for T1 MRI contrast agents and combination of low molecular weight T1 MRI contrast agents with different types of carriers have been investigated. Different types of materials for forming secure coating layers of SPIO and novel superparamagnetic particles with higher relaxivity values have been explored. Various types of ligands were applied to improve the capability to target tumor for both T1 and T2 contrast agents. Furthermore, MRI contrast agents for detection of tumor metabolism were also pursued.
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Affiliation(s)
- Weiren Cheng
- Institute of Materials Research and Engineering, Singapore Singapore Bioimaging Consortium, Singapore
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68
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Polasek M, Caravan P. Is macrocycle a synonym for kinetic inertness in Gd(III) Complexes? Effect of coordinating and noncoordinating substituents on inertness and relaxivity of Gd(III) chelates with DO3A-like ligands. Inorg Chem 2013; 52:4084-96. [PMID: 23517079 PMCID: PMC3640422 DOI: 10.1021/ic400227k] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Gadolinium chelates with octadentate ligands are widely used as contrast agents for magnetic resonance imaging (MRI), with macrocyclic ligands based on DO3A being preferred for the high kinetic inertness of their Gd chelates. A major challenge in the design of new bifunctional MRI probes is the need to control the rotational motion of the chelate, which greatly affects its relaxivity. In this work we explored facile alkylation of a secondary amine in macrocyclic DO3A-like ligands to create a short, achiral linkage to limit the undesired internal motion of chelates within larger molecular constructs. The acetate moiety on the trans nitrogen was also replaced with either a bidentate (ethoxyacetate, L1 or methyl picolinate, L2) or bulky monodentate (methyl phosphonate, L3) donor arm to give octa- or heptadentate ligands, respectively. The resultant Gd(III) complexes were all monohydrated (q = 1) and exhibited water residency times that spanned 2 orders of magnitude (τM = 2190 ± 170, 3500 ± 90, and 12.7 ± 3.8 ns at 37 °C for GdL1, GdL2, and GdL3, respectively). Alkylation of the secondary amine with a noncoordinating biphenyl moiety resulted in coordinatively saturated q = 0 complexes of octadentate ligands L1 and L2. Relaxivities were limited by slow water exchange and/or lack of water coligand. All complexes showed decreased inertness compared to [Gd(DO3A)] despite higher ligand denticity, and inertness was further decreased upon N-alkylation. These results demonstrate that high kinetic inertness and in vivo safety of Gd chelates with macrocyclic ligands should not be generalized.
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Affiliation(s)
- Miloslav Polasek
- The Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 149 Thirteenth Street, Suite 2301, Charlestown, MA 02129
| | - Peter Caravan
- The Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 149 Thirteenth Street, Suite 2301, Charlestown, MA 02129
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69
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Lanthanide(III) Complexes of Diethylenetriaminepentaacetic Acid (DTPA)-Bisamide Derivatives as Potential Agents for Bimodal (Optical/Magnetic Resonance) Imaging. Eur J Inorg Chem 2013. [DOI: 10.1002/ejic.201300196] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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70
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Tang J, Sheng Y, Hu H, Shen Y. Macromolecular MRI contrast agents: Structures, properties and applications. Prog Polym Sci 2013. [DOI: 10.1016/j.progpolymsci.2012.07.001] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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71
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Boros E, Caravan P. Structure-relaxivity relationships of serum albumin targeted MRI probes based on a single amino acid Gd complex. J Med Chem 2013; 56:1782-6. [PMID: 23391162 PMCID: PMC3656968 DOI: 10.1021/jm4000177] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The Gd(III) complex of DO3A-N-α-aminopropionate, Gd(DOTAla), was used to generate a small library of putative MRI probes targeted to human serum albumin (HSA). Ten compounds were synthesized via multistep organic synthesis, and the corresponding Gd complexes were investigated for their affinity to HSA, lipophilicity, and relaxivity in the absence and presence of HSA. Negative charge and moderate lipophilicity correlate with increased HSA affinity and relaxivity.
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Affiliation(s)
- Eszter Boros
- The Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 149 Thirteenth Street, Suite 2301, Charlestown, MA 02129
| | - Peter Caravan
- The Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 149 Thirteenth Street, Suite 2301, Charlestown, MA 02129
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72
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Xue S, Qiao J, Pu F, Cameron M, Yang JJ. Design of a novel class of protein-based magnetic resonance imaging contrast agents for the molecular imaging of cancer biomarkers. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2013; 5:163-79. [PMID: 23335551 DOI: 10.1002/wnan.1205] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Magnetic resonance imaging (MRI) of disease biomarkers, especially cancer biomarkers, could potentially improve our understanding of the disease and drug activity during preclinical and clinical drug treatment and patient stratification. MRI contrast agents with high relaxivity and targeting capability to tumor biomarkers are highly required. Extensive work has been done to develop MRI contrast agents. However, only a few limited literatures report that protein residues can function as ligands to bind Gd(3+) with high binding affinity, selectivity, and relaxivity. In this paper, we focus on reporting our current progress on designing a novel class of protein-based Gd(3+) MRI contrast agents (ProCAs) equipped with several desirable capabilities for in vivo application of MRI of tumor biomarkers. We will first discuss our strategy for improving the relaxivity by a novel protein-based design. We then discuss the effect of increased relaxivity of ProCAs on improving the detection limits for MRI contrast agent, especially for in vivo application. We will further report our efforts to improve in vivo imaging capability and our achievement in molecular imaging of cancer biomarkers with potential preclinical and clinical applications.
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Affiliation(s)
- Shenghui Xue
- Departments of Chemistry and Biology, Center for Diagnostics & Therapeutics, Georgia State University, Atlanta, GA, USA
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73
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Soleimani A, Martínez F, Economopoulos V, Foster PJ, Scholl TJ, Gillies ER. Polymer cross-linking: a nanogel approach to enhancing the relaxivity of MRI contrast agents. J Mater Chem B 2013; 1:1027-1034. [DOI: 10.1039/c2tb00352j] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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74
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Boros E, Polasek M, Zhang Z, Caravan P. Gd(DOTAla): a single amino acid Gd-complex as a modular tool for high relaxivity MR contrast agent development. J Am Chem Soc 2012; 134:19858-68. [PMID: 23157602 DOI: 10.1021/ja309187m] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
MR imaging at high magnetic fields benefits from an increased signal-to-noise ratio; however T(1)-based MR contrast agents show decreasing relaxivity (r(1)) at higher fields. High field, high relaxivity contrast agents can be designed by carefully controlling the rotational dynamics of the molecule. To this end, we investigated applications of the alanine analogue of Gd(DOTA), Gd(DOTAla). Fmoc-protected DOTAla suitable for solid phase peptide synthesis was synthesized and integrated into polypeptide structures. Gd(III) coordination results in very rigid attachment of the metal chelate to the peptide backbone through both the amino acid side chain and coordination of the amide carbonyl. Linear and cyclic monomers (GdL1, GdC1), dimers (Gd(2)L2, Gd(2)C2), and trimers (Gd(3)L3, Gd(3)C3) were prepared and relaxivities were determined at different field strengths ranging from 0.47 to 11.7 T. Amide carbonyl coordination was indirectly confirmed by determination of the hydration number q for the EuL1 integrated into a peptide backbone, q = 0.96 ± 0.09. The water residency time of GdL1 at 37 °C was optimal for relaxivity, τ(M) = 17 ± 2 ns. Increased molecular size leads to increased per Gd relaxivity (from r(1) = 7.5 for GdL1 to 12.9 mM(-1) s(-1) for Gd(3)L3 at 1.4 T, 37 °C). The cyclic, multimeric derivatives exhibited slightly higher relaxivities than the corresponding linearized multimers (Gd(2)C2: r(1) = 10.5 mM(-1) s(-1) versus Gd(2)C2-red r(1) = 9 mM(-1) s(-1) at 1.4 T, 37 °C). Overall, all six synthesized Gd complexes had higher relaxivities at low, intermediate, and high fields than the clinically used small molecule contrast agent [Gd(HP-DO3A)(H(2)O)].
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Affiliation(s)
- Eszter Boros
- The Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 149 Thirteenth Street, Suite 2301, Charlestown, Massachusetts 02129, United States
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75
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Esteban-Gómez D, de Blas A, Rodríguez-Blas T, Helm L, Platas-Iglesias C. Hyperfine Coupling Constants on Inner-Sphere Water Molecules of GdIII-Based MRI Contrast Agents. Chemphyschem 2012; 13:3640-50. [DOI: 10.1002/cphc.201200417] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Indexed: 01/02/2023]
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76
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Hsieh V, Jasanoff A. Bioengineered probes for molecular magnetic resonance imaging in the nervous system. ACS Chem Neurosci 2012; 3:593-602. [PMID: 22896803 DOI: 10.1021/cn300059r] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 07/11/2012] [Indexed: 01/20/2023] Open
Abstract
The development of molecular imaging probes has changed the nature of neurobiological research. Some of the most notable successes have involved the use of biological engineering techniques for the creation of fluorescent protein derivatives for optical imaging, but recent work has also led to a number of bioengineered probes for magnetic resonance imaging (MRI), the preeminent technique for noninvasive investigation of brain structure and function. Molecular MRI agents are beginning to be applied for experiments in the nervous system, where they have the potential to bridge from molecular to systems or organismic levels of analysis. Compared with canonical synthetic small molecule agents, biomolecular or semibiosynthetic MRI contrast agents offer special advantages due to their amenability to molecular engineering approaches, their properties in some cases as catalysts, and their specificity in targeting and ligand binding. Here, we discuss an expanding list of instances where biological engineering techniques have aided in the design of MRI contrast agents and reporter systems, examining both advantages and limitations of these types of probes for studies in the central nervous system.
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Affiliation(s)
- Vivian Hsieh
- Departments of Chemical Engineering, ‡Biological Engineering, §Brain & Cognitive Sciences, and ∥Nuclear Science & Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Room 16-561, Cambridge, Massachusetts 02139, United States
| | - Alan Jasanoff
- Departments of Chemical Engineering, ‡Biological Engineering, §Brain & Cognitive Sciences, and ∥Nuclear Science & Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Room 16-561, Cambridge, Massachusetts 02139, United States
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77
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Versluis B, Dremmen MHG, Nelemans PJ, Wildberger JE, Schurink GW, Leiner T, Backes WH. Dynamic contrast-enhanced MRI assessment of hyperemic fractional microvascular blood plasma volume in peripheral arterial disease: initial findings. PLoS One 2012; 7:e37756. [PMID: 22662212 PMCID: PMC3360623 DOI: 10.1371/journal.pone.0037756] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 04/26/2012] [Indexed: 11/19/2022] Open
Abstract
Objectives The aim of the current study was to describe a method that assesses the hyperemic microvascular blood plasma volume of the calf musculature. The reversibly albumin binding contrast agent gadofosveset was used in dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) to assess the microvascular status in patients with peripheral arterial disease (PAD) and healthy controls. In addition, the reproducibility of this method in healthy controls was determined. Materials and Methods Ten PAD patients with intermittent claudication and 10 healthy control subjects were included. Patients underwent contrast-enhanced MR angiography of the peripheral arteries, followed by one DCE MRI examination of the musculature of the calf. Healthy control subjects were examined twice on different days to determine normative values and the interreader and interscan reproducibility of the technique. The MRI protocol comprised dynamic imaging of contrast agent wash-in under reactive hyperemia conditions of the calf musculature. Using pharmacokinetic modeling the hyperemic fractional microvascular blood plasma volume (Vp, unit: %) of the anterior tibial, gastrocnemius and soleus muscles was calculated. Results Vp was significantly lower for all muscle groups in PAD patients (4.3±1.6%, 5.0±3.3% and 6.1±3.6% for anterior tibial, gastrocnemius and soleus muscles, respectively) compared to healthy control subjects (9.1±2.0%, 8.9±1.9% and 9.3±2.1%). Differences in Vp between muscle groups were not significant. The coefficient of variation of Vp varied from 10–14% and 11–16% at interscan and interreader level, respectively. Conclusions Using DCE MRI after contrast-enhanced MR angiography with gadofosveset enables reproducible assessment of hyperemic fractional microvascular blood plasma volume of the calf musculature. Vp was lower in PAD patients than in healthy controls, which reflects a promising functional (hemodynamic) biomarker for the microvascular impairment of macrovascular lesions.
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Affiliation(s)
- Bas Versluis
- Department of Radiology, Maastricht University Medical Center (MUMC+), Maastricht, The Netherlands
- Cardiovascular Research Institute Maastricht (CARIM), Maastricht, The Netherlands
| | - Marjolein H. G. Dremmen
- Department of Radiology, Maastricht University Medical Center (MUMC+), Maastricht, The Netherlands
| | - Patty J. Nelemans
- Department of Epidemiology, Maastricht University Medical Center (MUMC+), Maastricht, The Netherlands
| | - Joachim E. Wildberger
- Department of Radiology, Maastricht University Medical Center (MUMC+), Maastricht, The Netherlands
- Cardiovascular Research Institute Maastricht (CARIM), Maastricht, The Netherlands
| | - Geert-Willem Schurink
- Department of Surgery, Maastricht University Medical Center (MUMC+), Maastricht, The Netherlands
| | - Tim Leiner
- Department of Radiology, Maastricht University Medical Center (MUMC+), Maastricht, The Netherlands
- Cardiovascular Research Institute Maastricht (CARIM), Maastricht, The Netherlands
| | - Walter H. Backes
- Department of Radiology, Maastricht University Medical Center (MUMC+), Maastricht, The Netherlands
- Cardiovascular Research Institute Maastricht (CARIM), Maastricht, The Netherlands
- * E-mail:
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78
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Henoumont C, Laurent S, Muller RN, Vander Elst L. Effect of nonenzymatic glycosylation on the magnetic resonance imaging (MRI) contrast agent binding to human serum albumin. J Med Chem 2012; 55:4015-9. [PMID: 22420713 DOI: 10.1021/jm3000246] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Enhanced nonenzymatic glycosylation (NEG) of human serum albumin (HSA) is observed in diabetic patients. This modifies some of the physiological functions of HSA, as the binding of ligands. Some gadolinium complexes, commonly used as MRI contrast agents, have a high affinity for HSA, which enhances their efficacy. The aim of this study is to evaluate the possible influence of the NEG of HSA on its affinity for some gadolinium chelates.
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Affiliation(s)
- Céline Henoumont
- Department of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, University of Mons, 19 Avenue Maistriau, B-7000 Mons, Belgium
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79
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Moriggi L, Yaseen MA, Helm L, Caravan P. Serum albumin targeted, pH-dependent magnetic resonance relaxation agents. Chemistry 2012; 18:3675-86. [PMID: 22328098 PMCID: PMC3304010 DOI: 10.1002/chem.201103344] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Indexed: 11/11/2022]
Abstract
The objective of this work was the synthesis of serum albumin targeted, Gd(III)-based magnetic resonance imaging (MRI) contrast agents exhibiting a strong pH-dependent relaxivity. Two new complexes (Gd-glu and Gd-bbu) were synthesized based on the DO3A macrocycle modified with three carboxyalkyl substituents α to the three ring nitrogen atoms, and a biphenylsulfonamide arm. The sulfonamide nitrogen coordinates the Gd in a pH-dependent fashion, resulting in a decrease in the hydration state, q, as pH is increased and a resultant decrease in relaxivity (r(1)). In the absence of human serum albumin (HSA), r(1) increases from 2.0 to 6.0 mM(-1) s(-1) for Gd-glu and from 2.4 to 9.0 mM(-1) s(-1) for Gd-bbu from pH 5 to 8.5 at 37 °C, 0.47 T, respectively. These complexes (0.2 mM) are bound (>98.9 %) to HSA (0.69 mM) over the pH range 5-8.5. Binding to albumin increases the rotational correlation time and results in higher relaxivity. The r(1) increased 120 % (pH 5) and 550 % (pH 8.5) for Gd-glu and 42 % (pH 5) and 260 % (pH 8.5) for Gd-bbu. The increases in r(1) at pH 5 were unexpectedly low for a putative slow tumbling q=2 complex. The Gd-bbu system was investigated further. At pH 5, it binds in a stepwise fashion to HSA with dissociation constants K(d1)=0.65, K(d2)=18, K(d3)=1360 μM. The relaxivity at each binding site was constant. Luminescence lifetime titration experiments with the Eu(III) analogue revealed that the inner-sphere water ligands are displaced when the complex binds to HSA resulting in lower than expected r(1) at pH 5. Variable pH and temperature nuclear magnetic relaxation dispersion (NMRD) studies showed that the increased r(1) of the albumin-bound q=0 complexes is due to the presence of a nearby water molecule with a long residency time (1-2 ns). The distance between this water molecule and the Gd ion changes with pH resulting in albumin-bound pH-dependent relaxivity.
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Affiliation(s)
- Loïck Moriggi
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129 (USA)
| | - Mohammad A. Yaseen
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129 (USA)
| | - Lothar Helm
- Institut de Chimie Moléculaire et Biologique, Ecole Polytechnique Fédérale de Lausanne, EPFL-BCH, 1015 Lausanne (Switzerland)
| | - Peter Caravan
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129 (USA)
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80
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Caravan P, Zhang Z. Structure-Relaxivity Relationships among Targeted MR Contrast Agents. Eur J Inorg Chem 2012; 2012:1916-1923. [DOI: 10.1002/ejic.201101364] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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81
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Carr R, Di Bari L, Lo Piano S, Parker D, Peacock RD, Sanderson JM. A chiral probe for the acute phase proteins alpha-1-acid glycoprotein and alpha-1-antitrypsin based on europium luminescence. Dalton Trans 2012; 41:13154-8. [DOI: 10.1039/c2dt30143a] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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82
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Debroye E, Dehaen G, Eliseeva SV, Laurent S, Vander Elst L, Muller RN, Binnemans K, Parac-Vogt TN. A new metallostar complex based on an aluminum(iii) 8-hydroxyquinoline core as a potential bimodal contrast agent. Dalton Trans 2012; 41:10549-56. [DOI: 10.1039/c2dt30605k] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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83
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Li S, Jiang J, Zou J, Qiao J, Xue S, Wei L, Long R, Wang L, Castiblanco A, White N, Ngo J, Mao H, Liu ZR, Yang JJ. PEGylation of protein-based MRI contrast agents improves relaxivities and biocompatibilities. J Inorg Biochem 2011; 107:111-8. [PMID: 22178673 DOI: 10.1016/j.jinorgbio.2011.11.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 10/15/2011] [Accepted: 11/08/2011] [Indexed: 10/15/2022]
Abstract
Magnetic resonance imaging (MRI) has emerged as a leading diagnostic technique in clinical and preclinical settings. However, the application of MRI to assess specific disease markers for diagnosis and monitoring drug effect has been severely hampered by the lack of desired contrast agents with high relaxivities, and optimized in vivo retention time. We have reported the development of protein-based MRI contrast agents (ProCA1) by rational design of Gd(3+) binding sites into a stable protein resulting in significantly increased longitudinal (r(1)) and transverse (r(2)) relaxivities compared to Gd-DTPA. Here, we report a further improvement of protein contrast agents ProCA1 for in vivo imaging by protein modification with various sizes of polyethylene glycol (PEG) chain. PEGylation results in significant increases of both r(1) and r(2) relaxivities (up to 200%), and these high relaxivities persist even at field strengths up to 9.4 T. In addition, our experimental results demonstrate that modified contrast agents have significant improvement of in vivo MR imaging and biocompatibilities including dose efficiency, protein solubility, blood retention time and decreased immunogenicity. Such improvement can be important to the animal imaging and pre-clinical research at high or ultra-high field where there is an urgent need for molecular imaging probes and optimized contrast agent.
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Affiliation(s)
- Shunyi Li
- Department of Chemistry and Biology, Georgia State University, Atlanta, GA 30303, USA
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84
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Garimella PD, Datta A, Romanini DW, Raymond KN, Francis MB. Multivalent, high-relaxivity MRI contrast agents using rigid cysteine-reactive gadolinium complexes. J Am Chem Soc 2011; 133:14704-9. [PMID: 21800868 PMCID: PMC3188312 DOI: 10.1021/ja204516p] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
MRI contrast agents providing very high relaxivity values can be obtained through the attachment of multiple gadolinium(III) complexes to the interior surfaces of genome-free viral capsids. In previous studies, the contrast enhancement was predicted to depend on the rigidity of the linker attaching the MRI agents to the protein surface. To test this hypothesis, a new set of Gd-hydroxypyridonate based MRI agents was prepared and attached to genetically introduced cysteine residues through flexible and rigid linkers. Greater contrast enhancements were seen for MRI agents that were attached via rigid linkers, validating the design concept and outlining a path for future improvements of nanoscale MRI contrast agents.
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Affiliation(s)
- Praveena D. Garimella
- Department of Chemistry, University of California, Berkeley, California 94720-1460
- Materials Sciences Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720-1460
| | - Ankona Datta
- Department of Chemistry, University of California, Berkeley, California 94720-1460
| | - Dante W. Romanini
- Department of Chemistry, University of California, Berkeley, California 94720-1460
- Materials Sciences Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720-1460
| | - Kenneth N. Raymond
- Department of Chemistry, University of California, Berkeley, California 94720-1460
| | - Matthew B. Francis
- Department of Chemistry, University of California, Berkeley, California 94720-1460
- Materials Sciences Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720-1460
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85
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Bhuniya S, Moon H, Lee H, Hong KS, Lee S, Yu DY, Kim JS. Uridine-based paramagnetic supramolecular nanoaggregate with high relaxivity capable of detecting primitive liver tumor lesions. Biomaterials 2011; 32:6533-40. [DOI: 10.1016/j.biomaterials.2011.05.054] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Accepted: 05/17/2011] [Indexed: 10/18/2022]
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86
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Active gastrointestinal hemorrhage identification by blood pool contrast-enhanced magnetic resonance angiography. Pediatr Radiol 2011; 41:1198-200. [PMID: 21594539 DOI: 10.1007/s00247-011-2139-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 03/21/2011] [Accepted: 03/25/2011] [Indexed: 10/18/2022]
Abstract
Localization of the source of gastrointestinal hemorrhage can be challenging. Currently, this is often accomplished with tagged red blood cell scintigraphy, with attendant ionizing radiation and relatively poor spatial resolution. We describe an analogous method of detecting acute gastrointestinal hemorrhage by enhanced MRI with blood pool contrast agent. Briefly, following precontrast fat-suppressed volumetric T1-weighted image acquisition, single-dose gadofosveset trisodium, a blood pool agent, is administered. Then serial post-T1-weighted images are obtained. This technique is a novel method for evaluating gastrointestinal hemorrhage.
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87
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Majos A, Wolak T, Sapieha M, Olszycki M, Bogorodzki P, Stefańczyk L. Dynamic T1 functional MRI examinations with use of blood pool contrast agent--an approach to optimization of the technique. Clin Imaging 2011; 35:385-90. [PMID: 21872129 DOI: 10.1016/j.clinimag.2010.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 09/18/2010] [Indexed: 11/17/2022]
Abstract
The goal was to optimize dynamic T1 imaging for functional MRI (fMRI) examinations. For each of the 10 healthy subjects T1 3D gradient echo sequence (GRE) sequences were provided immediately after administration of blood pool contrast agent then every 2 h when subjects performed block finger tapings. Dynamic T1 fMRI is sensitive to detect cortical activations up to 6 h after BPCA administration. fMRI should be conducted within 2 h of CA administration, which is enough time for a typical fMRI experiment procedure.
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Affiliation(s)
- Agata Majos
- Radiology Dep, Medical University of Lodz, Poland, 90-153 Lodz, Kopcinskiego 22.
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88
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Vanasschen C, Bouslimani N, Thonon D, Desreux JF. Gadolinium DOTA Chelates Featuring Alkyne Groups Directly Grafted on the Tetraaza Macrocyclic Ring: Synthesis, Relaxation Properties, “Click” Reaction, and High-Relaxivity Micelles. Inorg Chem 2011; 50:8946-58. [DOI: 10.1021/ic2010997] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Christian Vanasschen
- Coordination and Radiochemistry, University of Liège, Sart Tilman B16, B4000 Liège, Belgium
| | - Nouri Bouslimani
- Coordination and Radiochemistry, University of Liège, Sart Tilman B16, B4000 Liège, Belgium
| | - David Thonon
- Coordination and Radiochemistry, University of Liège, Sart Tilman B16, B4000 Liège, Belgium
| | - Jean F. Desreux
- Coordination and Radiochemistry, University of Liège, Sart Tilman B16, B4000 Liège, Belgium
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89
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Frullano L, Caravan P. Strategies for the preparation of bifunctional gadolinium(III) chelators. Curr Org Synth 2011; 8:535-565. [PMID: 22375102 DOI: 10.2174/157017911796117250] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The development of gadolinium chelators that can be easily and readily linked to various substrates is of primary importance for the development high relaxation efficiency and/or targeted magnetic resonance imaging (MRI) contrast agents. Over the last 25 years a large number of bifunctional chelators have been prepared. For the most part, these compounds are based on ligands that are already used in clinically approved contrast agents. More recently, new bifunctional chelators have been reported based on complexes that show a more potent relaxation effect, faster complexation kinetics and in some cases simpler synthetic procedures. This review provides an overview of the synthetic strategies used for the preparation of bifunctional chelators for MRI applications.
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Affiliation(s)
- Luca Frullano
- Case Western Reserve University. 11100 Euclid Ave Cleveland, OH 44106
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90
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Giardiello M, Botta M, Lowe MP. Synthesis of lanthanide(III) complexes appended with a diphenylphosphinamide and their interaction with human serum albumin. J INCL PHENOM MACRO 2011. [DOI: 10.1007/s10847-011-0009-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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91
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Abstract
Molecular MRI plays an important role in studying molecular and cellular processes associated with heart disease. Targeted probes that recognize important biomarkers of atherosclerosis, apoptosis, necrosis, angiogenesis, thrombosis and inflammation have been developed. This review discusses the properties of chemically different contrast agents including iron oxide nanoparticles, gadolinium-based nanoparticles or micelles, discrete peptide conjugates and activatable probes. Numerous examples of contrast agents based on these approaches have been used in preclinical MRI of cardiovascular diseases. Clinical applications are still under investigation for some selected agents with highly promising initial results. Molecular MRI shows great potential for the detection and characterization of a wide range of cardiovascular diseases, as well as for monitoring response to therapy.
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92
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Grogna M, Cloots R, Luxen A, Jérôme C, Passirani C, Lautram N, Desreux JF, Detrembleur C. Convenient grafting through approach for the preparation of stealth polymeric blood pool magnetic resonance imaging contrast agents. ACTA ACUST UNITED AC 2011. [DOI: 10.1002/pola.24805] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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93
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Jacques V, Dumas S, Sun WC, Troughton JS, Greenfield MT, Caravan P. High-relaxivity magnetic resonance imaging contrast agents. Part 2. Optimization of inner- and second-sphere relaxivity. Invest Radiol 2011; 45:613-24. [PMID: 20808234 DOI: 10.1097/rli.0b013e3181ee6a49] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
RATIONALE AND OBJECTIVES The observed relaxivity of gadolinium-based contrast agents has contributions from the water molecule(s) that bind directly to the gadolinium ion (inner-sphere water), long-lived water molecules and exchangeable protons that make up the second-sphere of coordination, and water molecules that diffuse near the contrast agent (outer-sphere). Inner- and second-sphere relaxivity can both be increased by optimization of the lifetimes of the water molecules and protons in these coordination spheres, the rotational motion of the complex, and the electronic relaxation of the gadolinium ion. We sought to identify new high-relaxivity contrast agents by systematically varying the donor atoms that bind directly to gadolinium to increase inner-sphere relaxivity and concurrently including substituents that influence the second-sphere relaxivity. METHODS Twenty gadolinium-1,4,7,10-tetraazacyclo-dodecane-N,N',N″,N'″-tetraacetato derivatives were prepared and their relaxivity determined in presence and absence of human serum albumin as a function of temperature and magnetic field. Data was analyzed to extract the underlying molecular parameters influencing relaxivity. Each compound had a common albumin-binding group and an inner-sphere donor set comprising the 4 tertiary amine N atoms from cyclen, an α-substituted acetate oxygen atom, 2 amide oxygen atoms, an inner-sphere water oxygen atom, and a variable donor group. Each amide nitrogen was substituted with different groups to promote hydrogen bonding with second-sphere water molecules. RESULTS Relativities at 0.47 and 1.4 T, 37°C, in serum albumin ranged from 16.0 to 58.1 mM(-1)s(-1) and from 12.3 to 34.8 mM(-1)s(-1), respectively. The reduction of inner-sphere water exchange typical of amide donor groups could be offset by incorporating a phosphonate or phenolate oxygen atom donor in the first coordination sphere, resulting in higher relaxivity. Amide nitrogen substitution with pendant phosphonate or carboxylate groups increased relaxivity by as much as 88% compared with the N-methyl amide analog. Second-sphere relaxivity contributed as much as 24 and 14 mM(-1)s(-1) at 0.47 and 1.4 T, respectively. CONCLUSIONS Water/proton exchange dynamics in the inner- and second-coordination sphere can be predictably tuned by choice of donor atoms and second-sphere substituents, resulting in high-relaxivity agents.
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94
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High relaxivity magnetic resonance imaging contrast agents. Part 1. Impact of single donor atom substitution on relaxivity of serum albumin-bound gadolinium complexes. Invest Radiol 2011; 45:600-12. [PMID: 20808235 DOI: 10.1097/rli.0b013e3181ee5a9e] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
RATIONALE AND OBJECTIVES The donor atoms that bind to gadolinium in contrast agents influence inner-sphere water exchange and electronic relaxation, both of which determine observed relaxivity. The effect of these molecular parameters on relaxivity is greatest when the contrast agent is protein bound. We sought to determine an optimal donor atom set to yield high relaxivity compounds. METHODS A total of 38 gadolinium-1,4,7,10-tetraazacyclo-dodecane-N,N',N'',N'''-tetraacetato derivatives were prepared and relaxivity was determined in the presence and absence of human serum albumin as a function of temperature and magnetic field. Each compound had a common albumin-binding group and differed only by substitution of different donor groups at one of the macrocycle nitrogens. Oxygen-17 isotope relaxometry at 7.05 T was performed to estimate water exchange rates. RESULTS Changing a single donor atom resulted in changes in water exchange rates ranging across 3 orders of magnitude. Donor groups increased water exchange rate in the order: phosphonate ∼ phenolate > α-substituted acetate > acetate > hydroxamate ∼ sulfonamide > amide ∼ pyridyl ∼ imidazole. Relaxivites at 0.47 and 1.4 T, 37°C, ranged from 12.3 to 55.6 mM(-1)s(-1) and from 8.3 to 32.6 mM(-1)s(-1) respectively. Optimal relaxivities were observed when the donor group was an α-substituted acetate. Electronic relaxation was slowest for the acetate derivatives as well. CONCLUSIONS Water exchange dynamics and relaxivity can be predictably tuned by choice of donor atoms.
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95
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Mastarone DJ, Harrison VS, Eckermann AL, Parigi G, Luchinat C, Meade TJ. A modular system for the synthesis of multiplexed magnetic resonance probes. J Am Chem Soc 2011; 133:5329-37. [PMID: 21413801 PMCID: PMC3086647 DOI: 10.1021/ja1099616] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We have developed a modular architecture for preparing high-relaxivity multiplexed probes utilizing click chemistry. Our system incorporates azide bearing Gd(III) chelates and a trialkyne scaffold with a functional group for subsequent modification. In optimizing the relaxivity of this new complex, we undertook a study of the linker length between a chelate and the scaffold to determine its effect on relaxivity. The results show a strong dependence on flexibility between the individual chelates and the scaffold with decreasing linker length leading to significant increases in relaxivity. Nuclear magnetic resonance dispersion (NMRD) spectra were obtained to confirm a 10-fold increase in the rotational correlation time from 0.049 to 0.60 ns at 310 K. We have additionally obtained a crystal structure demonstrating that modification with an azide does not impact the coordination of the lanthanide. The resulting multinuclear center has a 500% increase in per Gd (or ionic) relaxivity at 1.41 T versus small molecule contrast agents and a 170% increase in relaxivity at 9.4 T.
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Affiliation(s)
- Daniel J. Mastarone
- Department of Chemistry, Molecular Biosciences, Neurobiology and Physiology, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113
| | - Victoria S.R. Harrison
- Department of Chemistry, Molecular Biosciences, Neurobiology and Physiology, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113
| | - Amanda L. Eckermann
- Department of Chemistry, Molecular Biosciences, Neurobiology and Physiology, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113
| | - Giacomo Parigi
- CERM and Department of Chemistry, University of Florence, Florence, Italy
| | - Claudio Luchinat
- CERM and Department of Chemistry, University of Florence, Florence, Italy
| | - Thomas J. Meade
- Department of Chemistry, Molecular Biosciences, Neurobiology and Physiology, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113
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96
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Kundu A, Peterlik H, Krssak M, Bytzek AK, Pashkunova-Martic I, Arion VB, Helbich TH, Keppler BK. Strategies for the covalent conjugation of a bifunctional chelating agent to albumin: Synthesis and characterization of potential MRI contrast agents. J Inorg Biochem 2011; 105:250-5. [DOI: 10.1016/j.jinorgbio.2010.10.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 10/29/2010] [Accepted: 10/29/2010] [Indexed: 02/04/2023]
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97
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Chang YH, Chen CY, Singh G, Chen HY, Liu GC, Goan YG, Aime S, Wang YM. Synthesis and Physicochemical Characterization of Carbon Backbone Modified [Gd(TTDA)(H2O)]2− Derivatives. Inorg Chem 2011; 50:1275-87. [DOI: 10.1021/ic101799c] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
| | - Chiao-Yun Chen
- Department of Medical Imaging, Kaohsiung Medical University Hospital
- Department of Radiology
| | - Gyan Singh
- Department of Biological Science and Technology
| | | | - Gin-Chung Liu
- Department of Medical Imaging, Kaohsiung Medical University Hospital
- Department of Radiology
| | - Yih-Gang Goan
- Department of Surgery, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
- Department of Nursing, Yuh-Ing Junior College of Health Care & Management, Kaohsiung, Taiwan
| | - Silvio Aime
- Department of Chemistry IFM and Molecular Imaging Center, University of Torino, Torino, Italy
| | - Yun-Ming Wang
- Department of Biological Science and Technology
- Institute of Molecular Medicine and Bioengineering
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98
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Majos A, Wolak T, Bogorodzki P, Tybor K, Sapieha M, Stefańczyk L. A blood pool contrast aided T1 functional MRI in patients with brain tumors--a preliminary study. Neuroradiology 2010; 53:523-31. [PMID: 21165612 PMCID: PMC3115140 DOI: 10.1007/s00234-010-0809-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 11/17/2010] [Indexed: 01/07/2023]
Abstract
INTRODUCTION The aim of our study was to determine the possibility of using a new functional technique: a T1-dependent sequence with administration of blood pool contrast agent (BPCA), in patients with brain tumors before and after surgical treatment. We also aimed to compare our results with those obtained using the fMRI technique, based on Blood Oxygenation Level-Dependent (BOLD) contrast. METHODS For each of our 14 oncologic patients (four before and ten after neurosurgical intervention), we obtained: a T1-3D GRE sequence (TR = 2.6 ms/TE = 1.1 ms/FA = 10°) after intravenous administration of BPCA (0.03 mmol/kg), as well as a T2*EPI sequence (TR = 3 s/TE = 50 ms/FA = 90°). Movement and/or tactile block type paradigms were carried out during both functional runs. SPM5 software was used for analysis. RESULTS For both functional techniques, maximum activations were localized in the same areas. There were no significant differences observed in the t values calculated for activations located in the primary motor cortex between groups of pre- and post-intervention patients (in the same functional technique). The mean values for T2* EPI examinations were 10.84 and 9.36, respectively. The mean t values for the T1 technique were lower, especially for the post-intervention patients (5.83 and 3.9, respectively). CONCLUSIONS The T1 technique can be used to detect functional areas in patients with brain tumors, pre-, and post-surgical intervention. This technique enables the evaluation of cortical centers that suffer from susceptibility artifacts when using the T2* BOLD technique. Activations found using both techniques have the same localization, with lower values for the T1 technique.
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Affiliation(s)
- Agata Majos
- Radiology Department, Medical University of Lodz, Poland, 90-153, Lodz Kopcinskiego 22.
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99
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Wild JM, Woodrow J, van Beek EJR, Misselwitz B, Johnson R. Evaluation of rHA labeled with Gd-DTPA for blood pool imaging and targeted contrast delivery. CONTRAST MEDIA & MOLECULAR IMAGING 2010; 5:39-43. [PMID: 20140975 DOI: 10.1002/cmmi.366] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A new contrast agent was developed by linking Gd-DTPA chelate to recombinant human albumin in the laboratory. The molar relaxivity of the new agent was tested in aqueous solution at B(0) 1.5 T and temperature 20 degrees C. The soluble compound had a higher molar longitudinal relaxivity and molar transverse relaxivity in water (r(1) = 7.2 s(-1) mM(-1), r(2) = 18.4 s(-1) mM(-1)) than those measured for Gd-DTPA solution (r(1) = 3.5 s(-1) mM(-1), r(2) = 5.5 s(-1) mM(-1)). The performance of the compound as a blood pool agent was investigated with soluble and microparticulate forms of the compound and comparisons were made with Gd-DTPA and the polymeric blood-pool agent, Gadomer. T(1)-weighted imaging experiments show that the soluble compound acts as a highly effective blood pool agent with hyperintensity in the vasculature persisting beyond 2 h post administration, compared with free Gd-DTPA, which was cleared from the blood pool after approximately 10 min. The clearance kinetics of the new agents were examined, due to the incomplete elimination within 14 days post injection; both rHA labeled compounds are probably not suitable for development as routine blood pool contrast media. However, with free sites on the Gd-loaded rHA molecule, there are possibilities for binding the agent to antibodies in the laboratory, which was demonstrated, and thus there exist potential applications for in vivo molecular imaging with this agent.
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Affiliation(s)
- Jim M Wild
- Unit of Academic Radiology, Royal Hallamshire Hospital, University of Sheffield, Sheffield, UK.
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100
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Henoumont C, Vander Elst L, Laurent S, Muller RN. Synthesis and physicochemical characterization of Gd-C4-thyroxin-DTPA, a potential MRI contrast agent. Evaluation of its affinity for human serum albumin by proton relaxometry, NMR diffusometry, and electrospray mass spectrometry. J Phys Chem B 2010; 114:3689-97. [PMID: 20175550 DOI: 10.1021/jp910961j] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Gd-C(4)-thyroxin-DTPA, a potential MRI contrast agent, was synthesized from Gd-DTPA and thyroxine, which interacts strongly with human serum albumin (HSA). It was characterized in water by its relaxometric properties and its stability versus zinc transmetalation. The affinity of the complex for HSA was studied by using three different methods: proton relaxometry, NMR diffusometry, and electrospray mass spectrometry. From the results, it appears that Gd-C(4)-thyroxin-DTPA exhibits a relatively high relaxivity (r(1) = 9.01 s(-1) mM(-1) at 1.5 T and 310 K), a good stability versus zinc transmetalation, and a strong interaction with HSA (K(a) approximately 10,000 M(-1) with two binding sites). The kinetics of the exchange between the bound and the free form of the complex was evaluated by the NMR diffusometry technique. Competition experiments have allowed the assignment of the chelate's binding site on HSA.
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Affiliation(s)
- C Henoumont
- Department of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, University of Mons, 19 avenue Maistriau, B-7000 Mons, Belgium
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