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Islam MK, Baek AR, Yang BW, Kim S, Hwang DW, Nam SW, Lee GH, Chang Y. Manganese (II) Complex of 1,4,7-Triazacyclononane-1,4,7-Triacetic Acid (NOTA) as a Hepatobiliary MRI Contrast Agent. Pharmaceuticals (Basel) 2023; 16:ph16040602. [PMID: 37111359 PMCID: PMC10141232 DOI: 10.3390/ph16040602] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 04/04/2023] [Accepted: 04/11/2023] [Indexed: 04/29/2023] Open
Abstract
Magnetic resonance imaging (MRI) is increasingly used to diagnose focal and diffuse liver disorders. Despite their enhanced efficacy, liver-targeted gadolinium-based contrast agents (GBCAs) raise safety concerns owing to the release of toxic Gd3+ ions. A π-conjugated macrocyclic chelate, Mn-NOTA-NP, was designed and synthesized as a non-gadolinium alternative for liver-specific MRI. Mn-NOTA-NP exhibits an r1 relaxivity of 3.57 mM-1 s-1 in water and 9.01 mM-1 s-1 in saline containing human serum albumin at 3 T, which is significantly greater than the clinically utilized Mn2+-based hepatobiliary drug, Mn-DPDP (1.50 mM-1 s-1), and comparable with that of GBCAs. Furthermore, the in vivo biodistribution and MRI enhancement patterns of Mn-NOTA-NP were similar to those of the Gd3+-based hepatobiliary agent, Gd-DTPA-EOB. Additionally, a 0.05 mmol/kg dose of Mn-NOTA-NP facilitated high-sensitivity tumor detection with tumor signal enhancement in a liver tumor model. Ligand-docking simulations further indicated that Mn-NOTA-NP differed from other hepatobiliary agents in their interactions with several transporter systems. Collectively, we demonstrated that Mn-NOTA-NP could be a new liver-specific MRI contrast agent.
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Affiliation(s)
- Md Kamrul Islam
- Institute of Biomedical Engineering Research, Kyungpook National University, Daegu 41405, Republic of Korea
| | - Ah-Rum Baek
- Institute of Biomedical Engineering Research, Kyungpook National University, Daegu 41405, Republic of Korea
| | - Byeong-Woo Yang
- Department of Medical and Biological Engineering, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea
| | - Soyeon Kim
- Division of RI-Convergence Research, Korea Institute of Radiological and Medical Sciences, Seoul 01812, Republic of Korea
| | - Dong Wook Hwang
- Department of Molecular Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea
| | - Sung-Wook Nam
- Department of Molecular Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea
| | - Gang-Ho Lee
- Department of Chemistry, Kyungpook National University, 80, Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea
| | - Yongmin Chang
- Department of Medical and Biological Engineering, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea
- Department of Molecular Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea
- Department of Radiology, Kyungpook National University Hospital, Daegu 41944, Republic of Korea
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2
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Baek AR, Kim HK, Kim S, Yang JU, Kang MK, Lee JJ, Sung B, Lee H, Kim M, Cho AE, Park JA, Chang Y. Effect of Structural Fine-Tuning on Chelate Stability and Liver Uptake of Anionic MRI Contrast Agents. J Med Chem 2022; 65:6313-6324. [PMID: 35418226 DOI: 10.1021/acs.jmedchem.2c00291] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The purpose of this study is to assess the physicochemical properties and MRI diagnostic efficacy of two newly synthesized 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-type Gd chelates, Gd-SucL and Gd-GluL, with an asymmetric α-substituted pendant arm as potential hepatocyte-specific magnetic resonance imaging contrast agents (MRI CAs). Our findings show that fine conformational changes in the chelating arm affect the in vivo pharmacokinetic behavior of the MRI CA, and that a six-membered chelating substituent of Gd-SucL is more advantageous in this system to avoid unwanted interactions with endogenous species. Gd-SucL exhibited a general DOTA-like chelate stability trend, indicating that all chelating arms retain coordination bonding. Finally, the in vivo diagnostic efficacy of highly stable Gd-SucL as a potential hepatocyte-specific MRI CA was evaluated using T1-weighted MR imaging on an orthotopic hepatocarcinoma model.
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Affiliation(s)
- Ah Rum Baek
- Institute of Biomedical Engineering Research, Kyungpook National University, 41405 Daegu, Korea
| | - Hee-Kyung Kim
- Preclinical Research Center, Daegu-Gyeongbuk Medical Innovation Foundation, 41061 Daegu, Korea
| | - Soyeon Kim
- Division of RI-Convergence Research, Korea Institute of Radiological and Medical Sciences, 139-706 Seoul, Korea
| | - Ji-Ung Yang
- Division of RI-Convergence Research, Korea Institute of Radiological and Medical Sciences, 139-706 Seoul, Korea
| | - Min-Kyoung Kang
- Laboratory Animal Center, KBIO Osong Medical Innovation Foundation, 28160 Osong, Korea
| | - Jae Jun Lee
- Laboratory Animal Center, KBIO Osong Medical Innovation Foundation, 28160 Osong, Korea
| | - Bokyung Sung
- Department of Medical & Biological Engineering, Kyungpook National University, 41944 Daegu, Korea
| | - Hyeji Lee
- Department of Biomedical Science, Kyungpook National University, 419944 Daegu, Korea
| | - Minsup Kim
- InCerebro Drug Discovery Institute, 01811 Seoul, Korea
| | - Art E Cho
- InCerebro Drug Discovery Institute, 01811 Seoul, Korea
| | - Ji-Ae Park
- Division of RI-Convergence Research, Korea Institute of Radiological and Medical Sciences, 139-706 Seoul, Korea
| | - Yongmin Chang
- Institute of Biomedical Engineering Research, Kyungpook National University, 41405 Daegu, Korea.,Department of Medical & Biological Engineering, Kyungpook National University, 41944 Daegu, Korea.,Department of Biomedical Science, Kyungpook National University, 419944 Daegu, Korea.,Department of Radiology, Kyungpook National University Hospital, 41944 Daegu, Korea.,Department of Molecular Medicine, School of Medicine, Kyungpook National University, 41944 Daegu, Korea
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3
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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: 827] [Impact Index Per Article: 165.4] [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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Mou J, Lin T, Huang F, Shi J, Chen H. A New Green Titania with Enhanced NIR Absorption for Mitochondria-Targeted Cancer Therapy. Theranostics 2017; 7:1531-1542. [PMID: 28529636 PMCID: PMC5436512 DOI: 10.7150/thno.17247] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 01/06/2017] [Indexed: 12/14/2022] Open
Abstract
A new kind of green titania (G-TiO2-x ) with obvious green color was facilely synthesized from black titania (B-TiO2-x ) through subsequently strong ultrasonication. Comparatively, this stable G-TiO2-x shows much enhanced near infrared (NIR) absorption, especially around 920 nm, which can be ascribed to the obvious change of TiO2-x lattice order owing to the effect of ultrasonication. This feature enables G-TiO2-x to be stimulated with 980 nm laser in the combined photodynamic therapy (PDT) and photothermal therapy (PTT), which is greatly beneficial for improving tissue penetration depth. Furthermore, since mitochondria are preferred subcellular organelles for PDT/PTT, G-TiO2-x was further designed to conjugate with triphenylphosphonium (TPP) ligand for mitochondria-targeted PDT/PTT to obtain precise cancer treatment. Attributing to the high mitochondria-targeting efficiency and simultaneously synergistic PDT/PTT, high phototherapeutic efficacy and safety with a much lower laser power density (980 nm, 0.72 W cm-2) and low materials dosage were achieved both in vitro and in vivo. In addition, negligible toxicity was found, indicating high biocompatibility. This novel G-TiO2-x could provide new strategies for future precise minimal/non-invasive tumor treatment.
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Affiliation(s)
| | | | | | | | - Hangrong Chen
- State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, P. R. China
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Svanedal I, Andersson F, Hedenström E, Norgren M, Edlund H, Satija SK, Lindman B, Rennie AR. Molecular Organization of an Adsorbed Layer: A Zwitterionic, pH-Sensitive Surfactant at the Air/Water Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:10936-10945. [PMID: 27690456 DOI: 10.1021/acs.langmuir.6b02598] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Neutron and X-ray reflection measurements have been used to study the structure of the adsorbed layer of a chelating surfactant at the air/liquid interface. The chelating surfactant 2-dodecyldiethylenetriaminepentaacetic acid (C12-DTPA) has a large headgroup containing eight donor atoms that can participate in the coordination of metal ions. The donor atoms are also titrating, resulting in an amphoteric surfactant that can adopt a number of differently charged species depending on the pH. Very strong coordination complexes are formed with metal ions, where the metal ion can be considered as part of the surfactant structure, in contrast to monovalent cations that act as regular counterions to the negative net charge. Adsorption was investigated over a large concentration interval, from well below the critical micelle concentration (cmc) to five times the cmc. The most striking result is the maximum in the surface excess found around the cmc, which is consistent with previous indications from surface tension measurements. Adding divalent metal ions has a limited effect on the adsorption at the air/liquid interface. The reason is the coordination of the metal ion, resulting in compensating deprotonation of the complex. Small variations in the headgroup area of different metal complexes are found, correlating to the conditional stability constants. Adding sodium chloride has a significant effect on the adsorption behavior, and the results indicate that the protonation equilibrium is more important than the ionic strength effects. From combined fits of the neutron and X-ray data, a model that consists of a thick headgroup region and a relatively thin dehydrated tail region is found, and it indicates that the tails are not fully extended and that the limiting area per molecule is determined by the bulky headgroup.
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Affiliation(s)
- Ida Svanedal
- Fibre Science and Communication Network (FSCN), Mid Sweden University , SE-851 70 Sundsvall, Sweden
| | - Fredrik Andersson
- Fibre Science and Communication Network (FSCN), Mid Sweden University , SE-851 70 Sundsvall, Sweden
| | - Erik Hedenström
- Fibre Science and Communication Network (FSCN), Mid Sweden University , SE-851 70 Sundsvall, Sweden
| | - Magnus Norgren
- Fibre Science and Communication Network (FSCN), Mid Sweden University , SE-851 70 Sundsvall, Sweden
| | - Håkan Edlund
- Fibre Science and Communication Network (FSCN), Mid Sweden University , SE-851 70 Sundsvall, Sweden
| | - Sushil K Satija
- NIST Center for Neutron Research , 100 Bureau Drive, MS 6100, Gaithersburg, Maryland 20899-6100, United States
| | - Björn Lindman
- Fibre Science and Communication Network (FSCN), Mid Sweden University , SE-851 70 Sundsvall, Sweden
| | - Adrian R Rennie
- Materials Physics and Centre for Neutron Scattering, Ångström Laboratory, Uppsala University , Box 516, SE-75120 Uppsala, Sweden
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Liu Z, Chen X. Simple bioconjugate chemistry serves great clinical advances: albumin as a versatile platform for diagnosis and precision therapy. Chem Soc Rev 2016; 45:1432-56. [PMID: 26771036 PMCID: PMC5227548 DOI: 10.1039/c5cs00158g] [Citation(s) in RCA: 282] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Albumin is the most abundant circulating protein in plasma and has recently emerged as a versatile protein carrier for drug targeting and for improving the pharmacokinetic profile of peptide or protein based drugs. Three drug delivery technologies related to albumin have been developed, which include the coupling of low-molecular weight drugs to exogenous or endogenous albumin, conjugating bioactive proteins by albumin fusion technology (AFT), and encapsulation of drugs into albumin nanoparticles. This review article starts with a brief introduction of human serum albumin (HSA), and then summarizes the mainstream chemical strategies of developing HSA binding molecules for coupling with drug molecules. Moreover, we also concisely condense the recent progress of the most important clinical applications of HSA-binding platforms, and specify the current challenges that need to be met for a bright future of HSA-binding.
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Affiliation(s)
- Zhibo Liu
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Xiaoyuan Chen
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA.
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7
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Sun X, Chen Y, Wu N, Kang CS, Song HA, Jin S, Fu Y, Bryant H, Frank JA, Chong HS. Application of aziridinium ring opening for preparation of optically active diamine and triamine analogues: Highly efficient synthesis and evaluation of DTPA-based MRI contrast enhancement agents. RSC Adv 2015; 5:94571-94581. [PMID: 26989478 DOI: 10.1039/c5ra11306g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Ring opening of aziridinium ions with nitrogen nucleophiles was applied to the highly efficient synthesis of optically active vicinal diamines and diethylene triamine pentaacetic acid (DTPA) analogues as potential magnetic resonance imaging (MRI) contrast enhancement agents. The synthetic method features a column-free isolation of the regiospecific and stereospecific nucleophilic substitution products of enantiomerically enriched aziridinium ions in excellent yield.
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Affiliation(s)
- Xiang Sun
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL, USA
| | - Yunwei Chen
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL, USA
| | - Ningjie Wu
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL, USA
| | - Chi Soo Kang
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL, USA
| | - Hyun A Song
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL, USA
| | - Shengnan Jin
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL, USA
| | - Yao Fu
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL, USA
| | - Henry Bryant
- Laboratory of Diagnostic Radiology Research, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Joseph A Frank
- Laboratory of Diagnostic Radiology Research, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Hyun-Soon Chong
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL, USA
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Abstract
This perspective outlines strategies towards the development of MR imaging probes that our lab has explored over the last 15 years. Namely, we discuss methods to enhance the signal generating capacity of MR probes and how to achieve tissue specificity through protein targeting or probe activation within the tissue microenvironment.
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Affiliation(s)
- Eszter Boros
- Athinoula A. Martinos Center for Biomedical 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, Department of Radiology Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Peter Caravan
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
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Boros E, Caravan. P. Probing the structure-relaxivity relationship of bis-hydrated Gd(DOTAla) derivatives. Inorg Chem 2015; 54:2403-10. [PMID: 25693053 PMCID: PMC4758459 DOI: 10.1021/ic503035f] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two structural isomers of the heptadentate chelator DO3Ala were synthesized, with carboxymethyl groups at either the 1,4- or 1,7-positions of the cyclen macrocycle. To interrogate the relaxivity under different rotatational dynamics regimes, the pendant primary amine was coupled to ibuprofen to enable binding to serum albumin. These chelators 6a and 6b form bis(aqua) ternary complexes with Gd(III) or Tb(III) as estimated from relaxivity measurements or luminescence lifetime measurements in water. The relaxivity of [Gd(6a)(H2O)2] and [Gd(6b)(H2O)2] was measured in the presence and absence of coordinating anions prevalent in vivo such as phosphate, lactate, and bicarbonate and compared with data attained for the q = 2 complex [Gd(DO3A)(H2O)2]. We found that relaxivity was reduced through formation of ternary complexes with lactate and bicarbonate, albeit to a lesser degree then the relaxivity of Gd(DO3A). In the presence of 100-fold excess phosphate, relaxivity was slightly increased and typical for q = 2 complexes of this size (8.3 mM(-1) s(-1) and 9.5 mM(-1) s(-1), respectively, at 37 °C, 60 MHz). Relaxivity for the complexes in the presence of HSA corresponded well to relaxivity obtained for complexes with reduced access for inner-sphere water (13.5 and 12.7 mM(-1) s(-1) at 37 °C, 60 MHz). Mean water residency time at 37 °C was determined using temperature-dependent (17)O-T2 measurements at 11.7 T and calculated to be (310)τM = 23 ± 1 ns for both structural isomers. Kinetic inertness under forcing conditions (pH 3, competing DTPA ligand) was found to be comparable to [Gd(DO3A)(H2O)]. Overall, we found that the replacement of one of the acetate arms of DO3A with an amino-propionate arm does not significantly alter the relaxometric and kinetic inertness properties of the corresponding Gd complexes; however, it does provide access to easily functionalizable q = 2 derivatives.
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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
| | - 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, Massachusetts 02129, United States
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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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Molecular imaging of EGFR/HER2 cancer biomarkers by protein MRI contrast agents. J Biol Inorg Chem 2013; 19:259-70. [PMID: 24366655 DOI: 10.1007/s00775-013-1076-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 12/06/2013] [Indexed: 12/22/2022]
Abstract
Epidermal growth factor receptor (EGFR) and HER2 are major prognosis biomarkers and drug targets overexpressed in various types of cancer cells. There is a pressing need to develop MRI contrast agents capable of enhancing the contrast between normal tissues and tumors with high relaxivity, capable of targeting tumors, and with high intratumoral distribution and minimal toxicity. In this review, we first discuss EGFR signaling and its role in tumor progression as a major drug target. We then report our progress in the development of protein contrast agents with significant improvement of both r1 and r2 relaxivities, pharmacokinetics, in vivo retention time, and in vivo dose efficiency. Finally, we report our effort in the development of EGFR-targeted protein contrast agents with the capability to cross the endothelial boundary and with good tissue distribution across the entire tumor mass. The noninvasive capability of MRI to visualize spatially and temporally the intratumoral distribution as well as quantify the levels of EGFR and HER2 would greatly improve our ability to track changes of the biomarkers during tumor progression, monitor treatment efficacy, aid in patient selection, and further develop novel targeted therapies for clinical application.
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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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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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Chen SH, Kuo YT, Singh G, Cheng TL, Su YZ, Wang TP, Chiu YY, Lai JJ, Chang CC, Jaw TS, Tzou SC, Liu GC, Wang YM. Development of a Gd(III)-based receptor-induced magnetization enhancement (RIME) contrast agent for β-glucuronidase activity profiling. Inorg Chem 2012; 51:12426-35. [PMID: 23116118 DOI: 10.1021/ic301827p] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
β-Glucuronidase is a key lysosomal enzyme and is often overexpressed in necrotic tumor masses. We report here the synthesis of a pro receptor-induced magnetization enhancement (pro-RIME) magnetic resonance imaging (MRI) contrast agent ([Gd(DOTA-FPβGu)]) for molecular imaging of β-glucuronidase activity in tumor tissues. The contrast agent consists of two parts, a gadolinium complex and a β-glucuronidase substrate (β-d-glucopyranuronic acid). The binding association constant (KA) of [Gd(DOTA-FPβGu)] is 7.42 × 10(2), which is significantly lower than that of a commercially available MS-325 (KA = 3.0 × 10(4)) RIME contrast agent. The low KA value of [Gd(DOTA-FPβGu)] is due to the pendant β-d-glucopyranuronic acid moiety. Therefore, [Gd(DOTA-FPβGu)] can be used for detection of β-glucuronidase through RIME modulation. The detail mechanism of enzymatic activation of [Gd(DOTA-FPβGu)] was elucidated by LC-MS. The kinetics of β-glucuronidase catalyzed hydrolysis of [Eu(DOTA-FPβGu)] at pH 7.4 best fit the Miechalis-Menten kinetic mode with Km = 1.38 mM, kcat = 3.76 × 10(3), and kcat/Km = 2.72 × 10(3) M(-1) s(-1). The low Km value indicates high affinity of β-glucuronidase for [Gd(DOTA-FPβGu)] at physiological pH. Relaxometric studies revealed that T1 relaxivity of [Gd(DOTA-FPβGu)] changes in response to the concentration of β-glucuronidase. Consistent with the relaxometric studies, [Gd(DOTA-FPβGu)] showed significant change in MR image signal in the presence of β-glucuronidase and HSA. In vitro and in vivo MR images demonstrated appreciable differences in signal enhancement in the cell lines and tumor xenografts in accordance to their expression levels of β-glucuronidase.
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Affiliation(s)
- Shih-Hsien Chen
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University , 100 Shih-Chuan first Road, Kaohsiung 807, Taiwan
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15
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Abd-Elgaliel WR, Tung CH. A cardiac tissue-specific binding agent of troponin I. MOLECULAR BIOSYSTEMS 2012; 8:2629-32. [PMID: 22828728 DOI: 10.1039/c2mb25178g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A fluorescently labeled, biphenylalanine-rich peptide was identified as a should be cardiac troponin I-specific binding agent with preferential staining affinity to myocardium tissues and extremely low staining to other stromal components. Fluorescence images demonstrate that this new peptide is an excellent contrast agent useful for examining troponin I structural distribution and expression density within heart tissue sections. It provides a clear contrast between myocardial cells and the surrounding collagen matrix.
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Affiliation(s)
- Wael R Abd-Elgaliel
- Department of Translational Imaging, Methodist Hospital Research Institute, Weill Cornell Medical College, Houston, TX, USA.
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16
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Leporq B, Dumortier J, Pilleul F, Beuf O. 3D-liver perfusion MRI with the MS-325 blood pool agent: A noninvasive protocol to asses liver fibrosis. J Magn Reson Imaging 2012; 35:1380-7. [DOI: 10.1002/jmri.23594] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 12/28/2011] [Indexed: 01/23/2023] Open
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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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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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Leporq B, Beuf O, Pilleul F. IRM de perfusion hépatique avec un agent de contraste à rémanence vasculaire. ACTA ACUST UNITED AC 2011; 92:257-61. [DOI: 10.1016/j.jradio.2011.02.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Revised: 05/27/2009] [Accepted: 02/08/2011] [Indexed: 01/17/2023]
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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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Bumb A, Brechbiel MW, Choyke P. Macromolecular and dendrimer-based magnetic resonance contrast agents. Acta Radiol 2010; 51:751-67. [PMID: 20590365 DOI: 10.3109/02841851.2010.491091] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Magnetic resonance imaging (MRI) is a powerful imaging modality that can provide an assessment of function or molecular expression in tandem with anatomic detail. Over the last 20-25 years, a number of gadolinium-based MR contrast agents have been developed to enhance signal by altering proton relaxation properties. This review explores a range of these agents from small molecule chelates, such as Gd-DTPA and Gd-DOTA, to macromolecular structures composed of albumin, polylysine, polysaccharides (dextran, inulin, starch), poly(ethylene glycol), copolymers of cystamine and cystine with GD-DTPA, and various dendritic structures based on polyamidoamine and polylysine (Gadomers). The synthesis, structure, biodistribution, and targeting of dendrimer-based MR contrast agents are also discussed.
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Affiliation(s)
- Ambika Bumb
- Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Martin W. Brechbiel
- Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Peter Choyke
- Molecular Imaging Program, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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Villaraza AJL, Bumb A, Brechbiel MW. Macromolecules, dendrimers, and nanomaterials in magnetic resonance imaging: the interplay between size, function, and pharmacokinetics. Chem Rev 2010; 110:2921-59. [PMID: 20067234 PMCID: PMC2868950 DOI: 10.1021/cr900232t] [Citation(s) in RCA: 471] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Aaron Joseph L. Villaraza
- Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ambika Bumb
- Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Martin W. Brechbiel
- Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Aime S, Caravan P. Biodistribution of gadolinium-based contrast agents, including gadolinium deposition. J Magn Reson Imaging 2010; 30:1259-67. [PMID: 19938038 DOI: 10.1002/jmri.21969] [Citation(s) in RCA: 385] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The biodistribution of approved gadolinium (Gd)-based contrast agents (GBCAs) is reviewed. After intravenous injection GBCAs distribute in the blood and the extracellular space and transiently through the excretory organs. Preclinical animal studies and the available clinical literature indicate that all these compounds are excreted intact. Elimination tends to be rapid and, for the most part, complete. In renally insufficient patients the plasma elimination half-life increases substantially from hours to days depending on renal function. In patients with impaired renal function and nephrogenic systemic fibrosis (NSF), the agents gadodiamide, gadoversetamide, and gadopentetate dimeglumine have been shown to result in Gd deposition in the skin and internal organs. In these cases, it is likely that the Gd is no longer present as the GBCA, but this has still not been definitively shown. In preclinical models very small amounts of Gd are retained in the bone and liver, and the amount retained correlates with the kinetic and thermodynamic stability of the GBCA with respect to Gd release in vitro. The pattern of residual Gd deposition in NSF subjects may be different than that observed in preclinical rodent models. GBCAs are designed to be used via intravenous administration. Altering the route of administration and/or the formulation of the GBCA can dramatically alter the biodistribution of the GBCA and can increase the likelihood of Gd deposition. J. Magn. Reson. Imaging 2009;30:1259-1267. (c) 2009 Wiley-Liss, Inc.
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Affiliation(s)
- Silvio Aime
- Department of Chemistry IFM and Molecular Imaging Center, University of Torino, Torino, Italy
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Caravan P. Protein-targeted gadolinium-based magnetic resonance imaging (MRI) contrast agents: design and mechanism of action. Acc Chem Res 2009; 42:851-62. [PMID: 19222207 DOI: 10.1021/ar800220p] [Citation(s) in RCA: 288] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Magnetic resonance imaging (MRI) is a powerful medical diagnostic technique: it can penetrate deep into tissue, provide excellent soft tissue contrast with sub-millimeter resolution, and does not employ ionizing radiation. Targeted contrast agents provide an additional layer of molecular specificity to the wealth of anatomical and functional information already attainable by MRI. However, the major challenge for molecular MR imaging is sensitivity: micromolar concentrations of Gd(III) are required to cause a detectable signal change, which makes detecting proteins by MRI a challenge. Protein-targeted MRI contrast agents are bifunctional molecules comprising a protein-targeting moiety and typically one or more gadolinium chelates for detection by MRI. The ability of the contrast agent to enhance the MR image is termed relaxivity, and it depends upon many molecular factors, including protein binding itself. As in other imaging modalities, protein binding provides the pharmacokinetic effect of concentrating the agent at the region of interest. Unique to MRI, protein binding provides the pharmacodynamic effect of increasing the relaxivity of the contrast agent, thereby increasing the MR signal. In designing new agents, optimization of both the targeting function and the relaxivity is critical. In this Account, we focus on optimization of the relaxivity of targeted agents. Relaxivity depends upon speciation, chemical structure, and dynamic processes, such as water exchange kinetics and rotational tumbling rates. We describe mechanistic studies that relate these factors to the observed relaxivities and use these findings as the basis of rational design of improved agents. In addition to traditional biochemical methods to characterize ligand-protein interactions, the presence of the metal ion enables more obscure biophysical techniques, such as relaxometry and electron nuclear double resonance, to be used to elucidate the mechanism of relaxivity differences. As a case study, we explore the mechanism of action of the serum-albumin-targeted angiography agent MS-325 and closely related compounds and show how small changes in the metal chelate can impact relaxivity. We found that, while protein binding generally improves relaxivity by slowing the tumbling rate of the complex, in some cases, the protein itself can also negatively affect hydration of the metal complex and/or inner-sphere water exchange. Drawing on these findings, we designed next-generation agents targeting albumin, fibrin, or collagen and incorporating up to four gadolinium chelates. Through judicious molecular design, we show that high-relaxivity complexes with high target affinity can be realized.
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Affiliation(s)
- Peter Caravan
- A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, 149 Thirteenth Street, Suite 2301, Charlestown, Massachusetts 02129
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Near-infrared fluorescence imaging with fluorescently labeled albumin: A novel method for non-invasive optical imaging of blood–brain barrier impairment after focal cerebral ischemia in mice. J Neurosci Methods 2009; 180:126-32. [DOI: 10.1016/j.jneumeth.2009.03.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Revised: 03/03/2009] [Accepted: 03/05/2009] [Indexed: 11/22/2022]
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Silvério S, Torres S, Martins AF, Martins JA, André JP, Helm L, Prata MIM, Santos AC, Geraldes CFGC. Lanthanide chelates of (bis)-hydroxymethyl-substituted DTTA with potential application as contrast agents in magnetic resonance imaging. Dalton Trans 2009:4656-70. [DOI: 10.1039/b823402g] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Dumelin CE, Trüssel S, Buller F, Trachsel E, Bootz F, Zhang Y, Mannocci L, Beck SC, Drumea-Mirancea M, Seeliger MW, Baltes C, Müggler T, Kranz F, Rudin M, Melkko S, Scheuermann J, Neri D. A portable albumin binder from a DNA-encoded chemical library. Angew Chem Int Ed Engl 2008; 47:3196-201. [PMID: 18366035 DOI: 10.1002/anie.200704936] [Citation(s) in RCA: 171] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Christoph E Dumelin
- Philochem AG, c/o ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland
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Overoye-Chan K, Koerner S, Looby RJ, Kolodziej AF, Zech SG, Deng Q, Chasse JM, McMurry TJ, Caravan P. EP-2104R: A Fibrin-Specific Gadolinium-Based MRI Contrast Agent for Detection of Thrombus. J Am Chem Soc 2008; 130:6025-39. [DOI: 10.1021/ja800834y] [Citation(s) in RCA: 180] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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29
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Dumelin C, Trüssel S, Buller F, Trachsel E, Bootz F, Zhang Y, Mannocci L, Beck S, Drumea-Mirancea M, Seeliger M, Baltes C, Müggler T, Kranz F, Rudin M, Melkko S, Scheuermann J, Neri D. A Portable Albumin Binder from a DNA-Encoded Chemical Library. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200704936] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Abstract
Even though the intrinsic magnetic resonance imaging (MRI) contrast is much more flexible than in other clinical imaging techniques, the diagnosis of several pathologies requires the involvement of contrast agents (CAs) that can enhance the difference between normal and diseased tissues by modifying their intrinsic parameters. MR CAs are indirect agents because they do not become visible by themselves as opposed to other imaging modalities. The signal enhancement produced by MRI CAs (i.e., the efficiency of the CAs) depends on their longitudinal (r1) and transverse (r2) relaxivity (expressed in s(-1) mmol(-1) 1), which is defined as the increase of the nuclear relaxation rate (the reciprocal of the relaxation time) of water protons produced by 1 mmol per liter of CA. Paramagnetic CAs (most of them complexes of gadolinium) are frequently used in clinics as extracellular, hepatobiliary or blood pool agents. Low molecular weight paramagnetic CAs have similar effects on R1 and R2, but the predominant effect at low doses is that of T1 shortening (and R1 enhancement). Thus, organs taking up such agents will become bright in a T1-weighted MRI sequence; these CAs are thus called positive contrast media. The CAs known as negative agents influence signal intensity mainly by shortening T2* and T2, which produces the darkening of the contrast-enhanced tissue. These CAs are generally composed of superparamagnetic nanoparticles, consisting of iron oxides (magnetite, Fe3O4, maghemite, gammaFe2O3, or other ferrites). Iron oxide nanoparticles are taken up by the monocyte-macrophage system, which explains their potential application as MRI markers of inflammatory and degenerative disorders. Most of the contemporary MRI CAs approved for clinical applications are non-specific for a particular pathology and report exclusively on the anatomy and the physiological status of various organs. A new generation of MRI CAs is progressively emerging in the current context of molecular imaging, agents that are designed to detect with a high specificity the cellular and molecular hallmarks of various pathologies.
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Affiliation(s)
- Carmen Burtea
- Department of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, University of Mons-Hainaut, 24, Avenue du Champ de Mars, 7000, Mons, Belgium.
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Dumas S, Troughton JS, Cloutier NJ, Chasse JM, McMurry TJ, Caravan P. A High Relaxivity Magnetic Resonance Imaging Contrast Agent Targeted to Serum Albumin. Aust J Chem 2008. [DOI: 10.1071/ch08164] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
EP-647 is a serum albumin-targeted magnetic resonance imaging contrast agent comprising a GdDTPA (DTPA, diethylenetriaminepentaacetate) chelate for magnetic resonance signal generation linked via a phosphodiester to a substituted biphenyl for albumin targeting. Albumin binding and relaxivity are higher than the benchmark magnetic resonance angiographic agent MS-325. EP-647 binds primarily to a unique site on serum albumin that is different from the MS-325 site and the binding sites of other drugs.
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Raitsimring AM, Astashkin AV, Baute D, Goldfarb D, Poluektov OG, Lowe MP, Zech SG, Caravan P. Determination of the hydration number of gadolinium(III) complexes by high-field pulsed 17O ENDOR spectroscopy. Chemphyschem 2007; 7:1590-7. [PMID: 16810729 DOI: 10.1002/cphc.200600138] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Pulsed 17O Mims electron-nuclear double resonance (ENDOR) spectroscopy at the W band (95 GHz) and D band (130 GHz) is used for the direct determination of the water coordination number (q) of gadolinium-based magnetic resonance imaging (MRI) contrast agents. Spectra of metal complexes in frozen aqueous solutions at approximately physiological concentrations can be obtained either in the presence or absence of protein targets. This method is an improvement over the 1H ENDOR method described previously, which involved the difference ENDOR spectrum of exchangeable protons from spectra taken in H2O and D2O. In addition to exchangeable water protons, the 1H ENDOR method is also sensitive to other exchangeable protons, and it is shown here that this method can overestimate hydration numbers for complexes with exchangeable protons at GdH distances similar to that of the coordinated water, for example, from NH groups. The 17O method does not suffer from this limitation. 17O ENDOR spectroscopy is applied to Gd(III) complexes containing zero, one, or two inner-sphere water molecules. In addition, 13C and 1H ENDOR studies were performed to assess the extent of methanol coordination, since methanol is used to produce a glass in these experiments. Under the experimental conditions used for the hydration number determination (30 mol % methanol), fewer than 15 % of the coordination sites were found to be occupied by methanol.
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Tyeklar Z, Dunham SU, Midelfort K, Scott DM, Sajiki H, Ong K, Lauffer RB, Caravan P, McMurry TJ. Structural, Kinetic, and Thermodynamic Characterization of the Interconverting Isomers of MS-325, a Gadolinium(III)-Based Magnetic Resonance Angiography Contrast Agent. Inorg Chem 2007; 46:6621-31. [PMID: 17625838 DOI: 10.1021/ic7006843] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The amphiphilic gadolinium complex MS-325 ((trisodium-{(2-(R)-[(4,4-diphenylcyclohexyl) phosphonooxymethyl] diethylenetriaminepentaacetato) (aquo)gadolinium(III)}) is a contrast agent for magnetic resonance angiography (MRA). MS-325 comprises a GdDTPA core with an appended phosphodiester moiety linked to a diphenylcyclohexyl group to facilitate noncovalent binding to serum albumin and extension of the plasma half-life in vivo. The chiral DTPA ligand (R) was derived from L-serine, and upon complexation with gadolinium, forms two interconvertible diastereomers, denoted herein as isomers A and B. X-ray crystallography of the tris(ethylenediamine)cobalt(III) salt derivative of isomer A revealed a structure in the polar acentric space group P32. The structure consisted of three independent molecules of the gadolinium complex in the asymmetric unit along with three Delta-[Co(en)3]3+ cations, and it represents an unusual example of spontaneous Pasteur resolution of the cobalt cation. The geometry of the coordination core was best described as a distorted trigonal prism, and the final R factor was 5.6%. The configuration of the chiral central nitrogen of the DTPA core was S. The Gd-water (2.47-2.48 A), the Gd-acetate oxygens (2.34-2.42 A), and the Gd-N bond distances (central N, 2.59-2.63 A; terminal N, 2.74-2.80 A) were similar to other reported GdDTPA structures. The structurally characterized single crystal was one of two interconvertable diastereomers (isomers A and B) that equilibrated to a ratio of 1.81 to 1 at pH 7.4 and were separable at elevated pH by ion-exchange chromatography. The rate of isomerization was highly pH dependent: k1 = (1.45 +/- 0.08) x 102[H+] + (4.16 +/- 0.30) x 105[H+]2; k-1 = (2.57 +/- 0.17) x 102[H+] + (7.54 +/- 0.60) x 105[H+]2.
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Zech SG, Eldredge HB, Lowe MP, Caravan P. Protein Binding to Lanthanide(III) Complexes Can Reduce the Water Exchange Rate at the Lanthanide. Inorg Chem 2007; 46:3576-84. [PMID: 17425306 DOI: 10.1021/ic070011u] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The GdIII-based magnetic resonance imaging contrast agent MS-325 targets the blood protein serum albumin, resulting in an increased efficacy (relaxivity) as a relaxation agent. MS-325 showed different relaxivities when bound to serum albumin from different species, e.g., r1=30.5 mM-1 s-1 (rabbit) vs 46.3 mM-1 s-1 (human) at 35 degrees C and 0.47 T. To investigate the mechanism for this difference, surrogate complexes were prepared where the GdIII ion was replaced by other LnIII ions. Fluorescence lifetime measurements of the EuIII analogue indicated that the hydration number was q=1 and did not change when bound to either human, rat, rabbit, pig, or dog serum albumin. The YbIII analogue, YbL1, was prepared and characterized by 1H NMR. Line-shape analysis of the paramagnetic-shifted 1H NMR resonances in the presence of increasing amounts of human (HSA) or rabbit (RSA) serum albumin allowed estimation of the transverse relaxation rate, R2, of these resonances for the protein-bound YbL1. The rotational correlation time of YbL1 was calculated from R2, and the Yb-H distance and was tauR=8+/-1 ns when bound to HSA and 13+/-2 ns when bound to RSA. The water exchange rate at the DyIII analogue, DyL1, was determined from variable-temperature R2 measurements at 9.4 T when DyL1 was bound to either HSA or RSA. At 37 degrees C, water exchange at DyL1 was (31+/-5)x10(6) s-1 when bound to HSA but (3.8+/-0.2)x10(6) s-1 when bound to RSA. Slower water exchange upon RSA binding explains the differences in relaxivity observed. The approach of using surrogate lanthanides to identify specific molecular parameters influencing relaxivity is applicable to other protein-targeted GdIII contrast agents.
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Affiliation(s)
- Stephan G Zech
- EPIX Pharmaceuticals, 67 Rogers Street, Cambridge, Massachusetts 02142, USA
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Zech SG, Sun WC, Jacques V, Caravan P, Astashkin AV, Raitsimring AM. Probing the water coordination of protein-targeted MRI contrast agents by pulsed ENDOR spectroscopy. Chemphyschem 2007; 6:2570-7. [PMID: 16294353 DOI: 10.1002/cphc.200500250] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A novel methodology based on electron-nuclear double resonance (ENDOR) spectroscopy is used for the direct determination of the water coordination number (q) of gadolinium-based magnetic resonance imaging (MRI) contrast agents. Proton ENDOR spectra can be obtained at approximately physiological concentrations for metal complexes in frozen aqueous solutions either in the presence or absence of protein targets. It is shown that, depending on the structure of the co-ligand, the water hydration number of a complex in aqueous solution can be significantly different to when the complex is noncovalently bound to a protein. From the ENDOR spectra of the exchangeable protons, precise information on the metal-proton distance can be derived as well. These essential parameters directly correlate with the efficacy of MRI contrast agents and should therefore aid the development of novel, highly efficient compounds targeted to various proteins.
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Affiliation(s)
- Stephan G Zech
- EPIX Pharmaceuticals, Inc., 67 Rogers Street, Cambridge, MA 02142, USA.
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36
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Yu G, Yamashita M, Aoshima K, Takahashi M, Oshikawa T, Takayanagi H, Laurent S, Burtea C, Vander Elst L, Muller RN. A glycosylated complex of gadolinium, a new potential contrast agent for magnetic resonance angiography? Bioorg Med Chem Lett 2007; 17:2246-9. [PMID: 17303417 DOI: 10.1016/j.bmcl.2007.01.067] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Revised: 01/19/2007] [Accepted: 01/19/2007] [Indexed: 10/23/2022]
Abstract
A new low-molecular weight dendrimer-like MRI contrast agent (Gd-D1) has been synthesized and characterized in vitro by proton and oxygen-17 relaxometry. Its pharmacokinetic parameters and biodistribution patterns were evaluated on rats. Its in vitro and in vivo properties, that is, the longitudinal relaxivity (defined as the increase of the water proton longitudinal relaxation rate induced by one millimole per liter of Gd-D1) equal to 5.6s(-1)mM(-1) at 20 MHz and 310 K, the elimination half-time equal to 85 min, and its low accumulation in liver and spleen, underline its potential as a blood-pool MRI contrast agent.
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Affiliation(s)
- G Yu
- Department of Nano-Materials, Graduate School of Science and Technology, Shizuoka University, Hamamatsu 432-8561, Japan
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Ou MH, Chen YM, Chang YH, Lu WK, Liu GC, Wang YM. Synthesis, complexation and water exchange properties of Gd(iii)–TTDA-mono and bis(amide) derivatives and their binding affinity to human serum albumin. Dalton Trans 2007:2749-59. [PMID: 17592591 DOI: 10.1039/b703211k] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
With the objective of tuning the lipophilicity of ligands and maintaining the neutrality and stability of Gd(III) chelate, we designed and synthesized two bis(amide) derivatives of TTDA, TTDA-BMA and TTDA-BBA, and a mono(amide) derivative, TTDA-N-MOBA. The ligand protonation constants and complex stability constants for various metal ions were determined in this study. The identification of the microscopic sites of protonation of the amide ligand by 1H NMR titrations show that the first protonation site occurs on the central nitrogen atom. The values of the stability constant of TTDA-mono and bis(amide) complex are significantly lower than those of TTDA and DTPA, but the selectivity constants of these ligands for Gd(III) over Zn(II) and Cu(II) are slightly higher than those of TTDA and DTPA. On the basis of the water-exchange rate values available for [Gd(TTDA-BMA)(H2O)], [Gd(TTDA-BBA)(H2O)] and [Gd(TTDA-N-MOBA)(H2O)]-, we can state that, in general, the replacement of one carboxylate group by an amide group decreases the water-exchange rate of the gadolinium(III) complexes by a factor of about three to five. The decrease in the exchange rate is explained in terms of a decreased steric crowding and charge effect around the metal ion when carboxylates are replaced by an amide group. In addition, to support the HSA protein binding studies of lipophilic [Gd(TTDA-N-MOBA)(H2O)]- and [Gd(TTDA-BBA)(H2O)] complexes, further protein-complex binding was studied by ultrafiltration and relaxivity studies. The binding constants (KA) of [Gd(TTDA-N-MOBA)(H2O)]- and [Gd(TTDA-BBA)(H2O)] are 8.6 x 10(2) and 1.0 x 10(4) dm3 mol(-1), respectively. The bound relaxivities (r1(b)) are 51.8 and 52 dm3 mmol(-1) s(-1), respectively. The KA value of [Gd(TTDA-BBA)(H2O)] is similar to that of MS-325 and indicates a stronger interaction of [Gd(TTDA-BBA)(H2O)] with HSA.
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Affiliation(s)
- Ming-Hung Ou
- Faculty of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan
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HIFUMI H, TANIMOTO A, HONDA A, CITTERIO D, SUZUKI K. Basic Design and Synthesis of Sulfonated Contrast Agents for Magnetic Resonance Imaging Based on Gadolinium Complexes. ANAL SCI 2007; 23:1159-65. [DOI: 10.2116/analsci.23.1159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Hiroki HIFUMI
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University
| | - Akihiro TANIMOTO
- Department of Diagnostic Radiology, Keio University School of Medicine
| | - Aki HONDA
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University
| | - Daniel CITTERIO
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University
| | - Koji SUZUKI
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University
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Kiessling F, Heilmann M, Lammers T, Ulbrich K, Subr V, Peschke P, Waengler B, Mier W, Schrenk HH, Bock M, Schad L, Semmler W. Synthesis and characterization of HE-24.8: a polymeric contrast agent for magnetic resonance angiography. Bioconjug Chem 2006; 17:42-51. [PMID: 16417250 DOI: 10.1021/bc0501909] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The physical and biological properties of a water-soluble polymeric contrast agent based on a complex of N-(2-hydroxypropyl)methacrylamide copolymer with gadolinium (HE-24.8) were investigated, and its potential for experimental magnetic resonance (MR) angiography was assessed. Relaxivities of Gd-DTPA-BMA, Gd-DTPA-HSA (human serum albumin), and HE-24.8 were determined at 1.5 T. Thermic stability and biocompatibility of HE-24.8 were assessed in vitro and by analyzing kinetics and organ distribution in rats for up to 2 weeks. For comparison, HE-24.8- and Gd-DTPA-HSA-enhanced micro-MR angiographies of brain, chest, and subcutaneous tumors in rats were performed. T1 relaxivity of HE-24.8 (21.3 +/- 1.1 mM(-1) s(-1)) was 5-fold higher than that of Gd-DTPA-BMA (4.1 +/- 0.1 mM(-1) s(-1)) and twice as high as that of Gd-DTPA-HSA (12.4 +/- 0.2 mM(-1) s(-1)). Varying the molecular weight of the polymer (15-46 kDa) did not significantly change the T1 relaxivity. In rats, 20 and 10% of the injected dose of HE-24.8 was detected at 24 and 168 h postinjection, respectively. Upon a relatively rapid initial renal clearance, no specific retention in any organ was noted, with some exception for the reticulo-endothelial system. No measurable release of gadolinium from the polymer-Gd complex or cell toxicity was observed during its incubation in aqueous environment. Excellent display of rat and tumor vascularization was achieved with Gd-DTPA-HSA and HE-24.8; however, contrast of vessels was higher in HE-24.8-enhanced scans. HE-24.8 is considered a macromolecular contrast agent highly suited for experimental MR studies.
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Affiliation(s)
- Fabian Kiessling
- Division of Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany.
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Ou MH, Tu CH, Tsai SC, Lee WT, Liu GC, Wang YM. Synthesis and Physicochemical Characterization of Two Gadolinium(III) TTDA-like Complexes and Their Interaction with Human Serum Albumin. Inorg Chem 2005; 45:244-54. [PMID: 16390062 DOI: 10.1021/ic050329r] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two novel derivatives of TTDA (3,6,10-tri(carboxymethyl)-3,6,10-triazadodecanedioic acid), TTDA-BOM and TTDA-N'-BOM, each having a benzyloxymethyl group, were synthesized. (17)O NMR longitudinal and transverse relaxation rates and chemical shifts of aqueous solutions of their Gd(III) complexes were measured at variable temperature with a magnetic field strength of 9.4 T. The water exchange rate (k(ex)(298)) values for [Gd(TTDA-BOM)(H(2)O)](2-) (117 x 10(6) s(-1)) and [Gd(TTDA-N'-BOM)(H(2)O)](2-) (131 x 10(6) s(-1)) are significantly higher than those of [Gd(DTPA)(H(2)O)](2-) (4.1 x 10(6) s(-1)) and [Gd(BOPTA)(H(2)O)](2-) (3.45 x 10(6) s(-1)). The rotational correlation time (tau) values for [Gd(TTDA-BOM)(H(2)O)](2-) (119 ps) and [Gd(TTDA-N'-BOM)(H(2)O)](2-) (125 ps) are higher than those of [Gd(DTPA)(H(2)O)](2-) (103 ps) and [Gd(TTDA)(H(2)O)](2-) (104 ps). The stepwise stoichiometric binding constants of [Gd(TTDA-BOM)(H(2)O)](2)(-) and [Gd(TTDA-N'-BOM)(H(2)O)](2)(-) bound to HSA are obtained by ultrafiltration studies. Fluorescent probe displacement studies exhibit that [Gd(TTDA-BOM)(H(2)O)](2-) and [Gd(TTDA-N'-BOM)(H(2)O)](2-) can displace dansylsarcosine from HSA with inhibition constants (K(i)) of 1900 and 1600 microM, respectively; however, they are not able to displace warfarin. These results indicate that [Gd(TTDA-BOM)(H(2)O)](2-) and [Gd(TTDA-N'-BOM)(H(2)O)](2-) have a weak binding to site II on HSA. In addition, the mean bound relaxivity (r(1b)) and bound relaxivity (r(1)(b)) values for the [Gd(TTDA-BOM)(H(2)O)](2-)/HSA and [Gd(TTDA-N'-BOM)(H(2)O)](2-)/HSA adducts are obtained by ultrafiltration and relaxivity studies, respectively. The bound relaxivity of these adducts values are significantly higher than those of [Gd(BOPTA)(H(2)O)](2-)/HSA and [Gd(DTPA-BOM(3))(H(2)O)](2-)/HSA. These results also suggest that bound relaxivity is site dependent. In binding sites studies of Gd(III) chelates to HSA, a significant decrease of the relaxation rates (R(1obs)) was observed for the [Eu(TTDA-BOM)(H(2)O)](2-) complex which was added to the [Gd(TTDA-N'-BOM)(H(2)O)](2-)/HSA solution, and this indicated that these Gd(III) complexes share the same HSA binding site. Finally, as measured by the Zn(II) transmetalation process, the kinetic stability of these Gd(III) complexes are significantly higher than that of [Gd(DTPA-BMA)(H(2)O)].
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Affiliation(s)
- Ming-Hung Ou
- Faculty of Medicinal and Applied Chemistry, Graduate Institute of Pharmaceutical Sciences, Kaohsiung Medical University, Republic of China
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41
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Caravan P, Amedio JC, Dunham SU, Greenfield MT, Cloutier NJ, McDermid SA, Spiller M, Zech SG, Looby RJ, Raitsimring AM, McMurry TJ, Lauffer RB. When are Two Waters Worse Than One? Doubling the Hydration Number of a Gd-DTPA Derivative Decreases Relaxivity. Chemistry 2005; 11:5866-74. [PMID: 16052656 DOI: 10.1002/chem.200500338] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The synthesis of a novel ligand, based on N-methyl-diethylenetriaminetetraacetate and containing a diphenylcyclohexyl serum albumin binding group (L1) is described and the coordination chemistry and biophysical properties of its Gd(III) complex Gd-L1 are reported. The Gd(III) complex of the diethylenetriaminepentaacetate analogue of the ligand described here (L2) is the MRI contrast agent MS-325. The effect of converting an acetate to a methyl group on metal-ligand stability, hydration number, water-exchange rate, relaxivity, and binding to the protein human serum albumin (HSA) is explored. The complex Gd-L1 has two coordinated water molecules in solution, that is, [Gd(L1)(H2O)2]2- as shown by D-band proton ENDOR spectroscopy and implied by 1H and 17O NMR relaxation rate measurements. The Gd-H(water) distance of the coordinated waters was found to be identical to that found for Gd-L2, 3.08 A. Loss of the acetate group destabilizes the Gd(III) complex by 1.7 log units (log K(ML) = 20.34) relative to the complex with L2. The affinity of Gd-L1 for HSA is essentially the same as that of Gd-L2. The water-exchange rate of the two coordinated waters on Gd-L1 (k(ex) = 4.4x10(5) s(-1)) is slowed by an order of magnitude relative to Gd-L2. As a result of this slow water-exchange rate, the observed proton relaxivity of Gd-L1 is much lower in a solution of HSA under physiological conditions (r1(obs) = 22.0 mM(-1) s(-1) for 0.1 mM Gd-L1 in 0.67 mM HSA, HEPES buffer, pH 7.4, 35 degrees C at 20 MHz) than that of Gd-L2 (r1(obs) = 41.5 mM(-1) s(-1)) measured under the same conditions. Despite having two exchangeable water molecules, slow water exchange limits the potential efficacy of Gd-L1 as an MRI contrast agent.
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Affiliation(s)
- Peter Caravan
- EPIX Pharmaceuticals, Inc., 67 Rogers Street, Cambridge, MA 02142-1118, USA.
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Thompson MK, Misselwitz B, Tso LS, Doble DMJ, Schmitt-Willich H, Raymond KN. In Vivo Evaluation of Gadolinium Hydroxypyridonate Chelates: Initial Experience as Contrast Media in Magnetic Resonance Imaging. J Med Chem 2005; 48:3874-7. [PMID: 15916439 DOI: 10.1021/jm049041m] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The effect of ligand structure on the magnetic resonance (MR) imaging and biodistribution of six gadolinium (Gd) chelates based on a hydroxypyridonate-terephthalimide (HOPO-TAM) ligand design was investigated. Modifications to the molecular structure of the Gd-HOPO-TAM chelates (hydrophilicity and aromatic group substitution) significantly influence the efficacy of imaging and biodistribution. MR imaging was performed on female mice after intravenous (iv) injection of 100 micromol of Gd/kg of body weight of the different complexes. The biodistribution results indicate that the liver uptake of the complexes is enhanced by a short poly(ethyleneoxy) (PEO) chain, while blood pool localization is facilitated by a very long PEO chain. There is a direct correlation between the blood pool localization of the complexes and the signal intensity of blood vessels in the MRI. The imaging results are consistent with in vitro NMR measurements that indicate long PEO chains increase image enhancement capabilities in the presence of serum albumin.
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Affiliation(s)
- Marlon K Thompson
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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Vander Elst L, Raynal I, Port M, Tisnès P, Muller RN. In vitro Relaxometric and Luminescence Characterization of P792 (Gadomelitol, Vistarem®), an Efficient and Rapid Clearance Blood Pool MRI Contrast Agent. Eur J Inorg Chem 2005. [DOI: 10.1002/ejic.200400919] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Wang YM, Li CR, Huang YC, Ou MH, Liu GC. Synthesis and Characterization of the Novel Monoamide Derivatives of Gd−TTDA. Inorg Chem 2004; 44:382-92. [PMID: 15651885 DOI: 10.1021/ic049401w] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
For this study, the N'-monoamide derivatives of TTDA (3,6,10-tri(carboxymethyl)-3,6,10-triazadodecanedioic acid), N'-methylamide (TTDA-MA), N'-benzylamide (TTDA-BA), and N'-2-methoxybenzylamide (TTDA-MOBA), were synthesized. Their protonation constants and stability constants (log K(ML)'s) formed with Ca(2+), Zn(2+), Cu(2+), and Gd(3+) were determined by potentiometric titration in 0.10 M Me(4)NCl at 25.0 +/- 0.1 degrees C. The relaxivity values of [Gd(TTDA-MA)](-), [Gd(TTDA-BA)](-), and [Gd(TTDA-MOBA)](-) remained constant with respect to pH changes over the range 4.5-12.0. The (17)O NMR chemical shift of H(2)O induced by [Dy(TTDA-MA)(H(2)O)](-) at pH 6.80 showed 0.9 inner-sphere water molecules. Water proton relaxivity values for [Gd(TTDA-MA)(H(2)O)](-), [Gd(TTDA-BA)(H(2)O)](-), and [Gd(TTDA-MOBA)(H(2)O)](-) at 37.0 +/- 0.1 degrees C and 20 MHz are 3.89, 4.21, and 4.25, respectively. The water-exchange lifetime (tau(M)) and rotational correlation time (tau(R)) of [Gd(TTDA-MA)(H(2)O)](-), [Gd(TTDA-BA)(H(2)O)](-), and [Gd(TTDA-MOBA)(H(2)O)](-) are obtained from reduced the (17)O relaxation rate and chemical shifts of H(2)(17)O. The (2)H NMR longitudinal relaxation rates of the deuterated diamagnetic lanthanum complexes for the rotational correlation time were also thoroughly investigated. The water-exchange rates (K(298)(ex) for [Gd(TTDA-MA)(H(2)O)](-), [Gd(TTDA-BA)(H(2)O)](-), and [Gd(TTDA-MOBA)(H(2)O)](-) are lower than that of [Gd(TTDA)(H(2)O)](2)(-) but significantly higher than those of [Gd(DTPA)(H(2)O)](2)(-) and [Gd(DTPA-BMA)(H(2)O)]. The rotational correlation times for [Gd(TTDA-BA)(H(2)O)](-) and [Gd(TTDA-MOBA)(H(2)O)](-) are significantly longer than those of [Gd(TTDA)(H(2)O)](2)(-) and [Gd(DTPA)(H(2)O)](2)(-) complexes. The marked increase of the relaxivity of [Gd(TTDA-BA)(H(2)O)](-) and [Gd(TTDA-MOBA)(H(2)O)](-) results mainly from their longer rotational correlation time. The noncovalent interaction between human serum albumin (HSA) and [Gd(TTDA-BA)(H(2)O)](-) and [Gd(TTDA-MOBA)(H(2)O)](-) complexes containing a hydrophobic substituent was investigated by measuring the water proton relaxation rate of the aqueous solutions. The binding association constant (K(A)) values are 1.0 +/- 0.2 x 10(3) and 1.3 +/- 0.2 x 10(3) M(-1) for [Gd(TTDA-BA)(H(2)O)](-) and [Gd(TTDA-MOBA)(H(2)O)](-), which indicates a stronger interaction of [Gd(TTDA-BA)(H(2)O)](-) and [Gd(TTDA-MOBA)(H(2)O)](-) with HSA.
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Affiliation(s)
- Yun-Ming Wang
- Faculty of Medicinal and Applied Chemistry, Graduate Institute of Pharmaceutical Sciences, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung, 807 Taiwan, Republic of China.
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Troughton JS, Greenfield MT, Greenwood JM, Dumas S, Wiethoff AJ, Wang J, Spiller M, McMurry TJ, Caravan P. Synthesis and Evaluation of a High Relaxivity Manganese(II)-Based MRI Contrast Agent. Inorg Chem 2004; 43:6313-23. [PMID: 15446878 DOI: 10.1021/ic049559g] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The manganese(II) ion has many favorable properties that lead to its potential use as an MRI contrast agent: high spin number, long electronic relaxation time, labile water exchange. The present work describes the design, synthesis, and evaluation of a novel Mn(II) complex (MnL1) based on EDTA and also contains a moiety that noncovalently binds the complex to serum albumin, the same moiety used in the gadolinium based contrast agent MS-325. Ultrafiltration albumin binding measurements (0.1 mM, pH 7.4, 37 degrees C) indicated that the complex binds well to plasma proteins (rabbit: 96 +/- 2% bound, human: 93 +/- 2% bound), and most likely to serum albumin (rabbit: 89 +/- 2% bound, human 98 +/- 2% bound). Observed relaxivities (+/- 5%) of the complex were measured (20 MHz, 37 degrees C, 0.1 mM, pH 7.4) in HEPES buffer (r(1) = 5.8 mM(-)(1) s(-)(1)), rabbit plasma (r(1) = 51 mM(-)(1) s(-)(1)), human plasma (r(1) = 46 mM(-)(1) s(-)(1)), 4.5% rabbit serum albumin (r(1) = 47 mM(-)(1) s(-)(1)), and 4.5% human serum albumin (r(1) = 48 mM(-)(1) s(-)(1)). The water exchange rate was near optimal for an MRI contrast agent (k(298) = 2.3 +/- 0.9 x 10(8) s(-)(1)). Variable temperature NMRD profiles indicated that the high relaxivity was due to slow tumbling of the albumin-bound complex and fast exchange of the inner sphere water. The concept of a high relaxivity Mn(II)-based contrast agent was validated by imaging at 1.5 T. In a rabbit model of carotid artery injury, MnL1 clearly delineated both arteries and veins while also distinguishing between healthy tissue and regions of vessel damage.
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Chan KWY, Barra S, Botta M, Wong WT. Novel gadolinium(III) polyaminocarboxylate macrocyclic complexes as potential magnetic resonance imaging contrast agents. J Inorg Biochem 2004; 98:677-82. [PMID: 15134912 DOI: 10.1016/j.jinorgbio.2004.02.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2003] [Revised: 01/21/2004] [Accepted: 02/13/2004] [Indexed: 11/23/2022]
Abstract
Two novel Gd(III) complexes with functionalised polyaminocarboxylate macrocycles, 1,4,7-tris(carboxymethyl)-9,24-dioxo-14,19-dioxa-1,4,7,10,23- pentaazacyclododecane (L(1)) and 1,4,7-tris(carboxymethyl)-9,25-dioxo-14,17,20-trioxa-1,4,7,10,23- pentaazacyclotridecane (L(2)), were prepared in good yield. Their potential use as magnetic resonance imaging (MRI) contrast agents (CAs) was evaluated by investigating their relaxation behaviour as a function of pH, temperature and magnetic field strength. The 1/T(1) proton relaxivities at 20 MHz and 25 degrees C of GdL(1) (5.87 mM(-1) s(-1)) and GdL(2) (6.14 mM(-1) s(-1)) were found to be significantly higher than the clinically used Gd 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (Gd(DOTA)(-)) and Gd diethylenetriaminepentaethanoic acid (Gd(DTPA)(2-)). The complexes possess one water molecule in the inner coordination sphere whose mean residence lifetime was estimated to be 1.1 and 1.5 micros at 25 degrees C by variable temperature (VT) (17)O NMR spectroscopy.
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Affiliation(s)
- Kannie Wai-Yan Chan
- Department of Chemistry and Open Laboratory of Chemical Biology of the Institute of Molecular Technology for Drug Discovery and Synthesis, The University of Hong Kong, Pokfulam Road, Hong Kong, PR China
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48
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Woods M, Kovacs Z, Sherry A. Targeted Complexes of Lanthanide(III) Ions as Therapeutic and Diagnostic Pharmaceuticals. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s1472-7862(02)00072-2] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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