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Li D, Kirberger M, Qiao J, Gui Z, Xue S, Pu F, Jiang J, Xu Y, Tan S, Salarian M, Ibhagui O, Hekmatyar K, Yang JJ. Protein MRI Contrast Agents as an Effective Approach for Precision Molecular Imaging. Invest Radiol 2024; 59:170-186. [PMID: 38180819 DOI: 10.1097/rli.0000000000001057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2024]
Abstract
ABSTRACT Cancer and other acute and chronic diseases are results of perturbations of common molecular determinants in key biological and signaling processes. Imaging is critical for characterizing dynamic changes in tumors and metastases, the tumor microenvironment, tumor-stroma interactions, and drug targets, at multiscale levels. Magnetic resonance imaging (MRI) has emerged to be a primary imaging modality for both clinical and preclinical applications due to its advantages over other modalities, including sensitivity to soft tissues, nondepth limitations, and the use of nonionizing radiation. However, extending the application of MRI to achieve both qualitative and quantitative precise molecular imaging with the capability to quantify molecular biomarkers for early detection, staging, and monitoring therapeutic treatment requires the capacity to overcome several major challenges including the trade-off between metal-binding affinity and relaxivity, which is an issue frequently associated with small chelator contrast agents. In this review, we will introduce the criteria of ideal contrast agents for precision molecular imaging and discuss the relaxivity of current contrast agents with defined first shell coordination water molecules. We will then report our advances in creating a new class of protein-targeted MRI contrast agents (ProCAs) with contributions to relaxivity largely derived from the secondary sphere and correlation time. We will summarize our rationale, design strategy, and approaches to the development and optimization of our pioneering ProCAs with desired high relaxivity, metal stability, and molecular biomarker-targeting capability, for precision MRI. From first generation (ProCA1) to third generation (ProCA32), we have achieved dual high r1 and r2 values that are 6- to 10-fold higher than clinically approved contrast agents at magnetic fields of 1.5 T, and their relaxivity values at high field are also significantly higher, which enables high resolution during small animal imaging. Further engineering of multiple targeting moieties enables ProCA32 agents that have strong biomarker-binding affinity and specificity for an array of key molecular biomarkers associated with various chronic diseases, while maintaining relaxation and exceptional metal-binding and selectivity, serum stability, and resistance to transmetallation, which are critical in mitigating risks associated with metal toxicity. Our leading product ProCA32.collagen has enabled the first early detection of liver metastasis from multiple cancers at early stages by mapping the tumor environment and early stage of fibrosis from liver and lung in vivo, with strong translational potential to extend to precision MRI for preclinical and clinical applications for precision diagnosis and treatment.
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Affiliation(s)
- Dongjun Li
- From the Center for Diagnostics and Therapeutics, Advanced Translational Imaging Facility, Department of Chemistry, Georgia State University, Atlanta, GA (D.L., M.K., J.Q., Z.G., S.X., P.F., J.J., S.T., M.S., O.I., K.H., J.J.Y.); and InLighta BioSciences, LLC, Marietta, GA (Y.X., J.J.Y)
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Stefania R, Palagi L, Di Gregorio E, Ferrauto G, Dinatale V, Aime S, Gianolio E. Seeking for Innovation with Magnetic Resonance Imaging Paramagnetic Contrast Agents: Relaxation Enhancement via Weak and Dynamic Electrostatic Interactions with Positively Charged Groups on Endogenous Macromolecules. J Am Chem Soc 2024; 146:134-144. [PMID: 38152996 PMCID: PMC10785807 DOI: 10.1021/jacs.3c06275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 12/14/2023] [Accepted: 12/15/2023] [Indexed: 12/29/2023]
Abstract
Gd-L1 is a macrocyclic Gd-HPDO3A derivative functionalized with a short spacer to a trisulfonated pyrene. When compared to Gd-HPDO3A, the increased relaxivity appears to be determined by both the higher molecular weight and the occurrence of an intramolecularly catalyzed prototropic exchange of the coordinated OH moiety. In water, Gd-L1 displayed a relaxivity of 7.1 mM-1 s-1 (at 298 K and 0.5 T), slightly increasing with the concentration likely due to the onset of intermolecular aggregation. A remarkably high and concentration-dependent relaxivity was measured in human serum (up to 26.5 mM-1 s-1 at the lowest tested concentration of 0.005 mM). The acquisition of 1H-nuclear magnetic relaxation dispersion (NMRD) and 17O-R2 vs T profiles allowed to get an in-depth characterization of the system. In vitro experiments in the presence of human serum albumin, γ-globulins, and polylysine, as well as using media mimicking the extracellular matrix, provided strong support to the view that the trisulfonated pyrene fosters binding interactions with the exposed positive groups on the surface of proteins, responsible for a remarkable in vivo hyperintensity in T1w MR images. The in vivo MR images of the liver, kidneys, and spleen showed a marked contrast enhancement in the first 10 min after the i.v. injection of Gd-L1, which was 2-6-fold higher than that for Gd-HPDO3A, while maintaining a very similar excretion behavior. These findings may pave the way to an improved design of MRI GBCAs, for the first time, based on the setup of weak and dynamic interactions with abundant positive groups on serum and ECM proteins.
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Affiliation(s)
- Rachele Stefania
- Department
of Molecular Biotechnology and Health Sciences, University of Torino, Torino 10126, Italy
- Department
of Science and Technological Innovation, University of Eastern Piedmont, Alessandria 15120, Italy
| | - Lorenzo Palagi
- Department
of Molecular Biotechnology and Health Sciences, University of Torino, Torino 10126, Italy
| | - Enza Di Gregorio
- Department
of Molecular Biotechnology and Health Sciences, University of Torino, Torino 10126, Italy
| | - Giuseppe Ferrauto
- Department
of Molecular Biotechnology and Health Sciences, University of Torino, Torino 10126, Italy
| | - Valentina Dinatale
- Department
of Molecular Biotechnology and Health Sciences, University of Torino, Torino 10126, Italy
| | | | - Eliana Gianolio
- Department
of Molecular Biotechnology and Health Sciences, University of Torino, Torino 10126, Italy
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Zhang Z, Wang H, Yang H, Song W, Dai L, Yu S, Liu X, Li T. Magnetic microswarm for MRI contrast enhancer. Chem Asian J 2022; 17:e202200561. [DOI: 10.1002/asia.202200561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/22/2022] [Indexed: 11/08/2022]
Affiliation(s)
- Zhanxiang Zhang
- Harbin Institute of Technology State Key Laboratory of Robotics and System CHINA
| | - Haocheng Wang
- Harbin Institute of Technology State Key Laboratory of Robotics and System CHINA
| | - Hua Yang
- Peking Union Medical College Hospital National Clinical Research Center for Obstetric & Gynecologic Diseases CHINA
| | - Wenping Song
- Harbin Institute of Technology State Key Laboratory of Robotics and System CHINA
| | - Lizhou Dai
- Harbin Institute of Technology State Key Laboratory of Robotics and System CHINA
| | - Shimin Yu
- Harbin Institute of Technology State Key Laboratory of Robotics and System CHINA
| | - Xuejia Liu
- The Fourth Affiliated Hospital of Harbin Medical University Department of Medical Imaging CHINA
| | - Tianlong Li
- Harbin Institute of Technology Mechanical Engineering 92 West Dazhi StreetMainhouse Room 125 150001 Harbin CHINA
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Hu H, Quintana J, Weissleder R, Parangi S, Miller M. Deciphering albumin-directed drug delivery by imaging. Adv Drug Deliv Rev 2022; 185:114237. [PMID: 35364124 DOI: 10.1016/j.addr.2022.114237] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 03/10/2022] [Accepted: 03/23/2022] [Indexed: 01/03/2023]
Abstract
Albumin is the most abundant plasma protein, exhibits extended circulating half-life, and its properties have long been exploited for diagnostics and therapies. Many drugs intrinsically bind albumin or have been designed to do so, yet questions remain about true rate limiting factors that govern albumin-based transport and their pharmacological impacts, particularly in advanced solid cancers. Imaging techniques have been central to quantifying - at a molecular and single-cell level - the impact of mechanisms such as phagocytic immune cell signaling, FcRn-mediated recycling, oncogene-driven macropinocytosis, and albumin-drug interactions on spatial albumin deposition and related pharmacology. Macroscopic imaging of albumin-binding probes quantifies vessel structure, permeability, and supports efficiently targeted molecular imaging. Albumin-based imaging in patients and animal disease models thus offers a strategy to understand mechanisms, guide drug development and personalize treatments.
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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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Hindel S, Heuchel L, Lüdemann L. Fractional calculus tracer kinetic compartment model for quantification of microvascular perfusion. Physiol Meas 2021; 42. [PMID: 34049294 DOI: 10.1088/1361-6579/ac067c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 05/26/2021] [Indexed: 11/11/2022]
Abstract
Objective. We evaluate a tracer kinetic model for quantification of physiological perfusion and microvascular residue time kurtosis (RTK) in skeletal muscle vasculature with first pass bolus experiments in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).Approach. A decreasing stretched Mittag-Leffler function (f1C model) was obtained as the impulse response solution of a rate equation of real-valued ('fractional') derivation order. The method was validated in skeletal muscle in the lower limb of seven female pigs examined by DCE-MRI. Dynamic imaging during blood pool contrast agent elimination was performed using a 3D gradient echo sequence with k-space sharing. Blood flow was augmented by continuous infusion of the vasodilator adenosine into the femoral artery increasing blood flow up to four times. Blood flow measured by a Doppler flow probe placed at the femoral artery served as ground truth.Main results. Goodness of fit and correlation with the Doppler measurements,r= 0.80 (P< 0.001), of the 4-parameter f1C model was comparable with the results obtained with a previously tested 6-parameter two-compartment (2C) model. The derivation orderαof the f1C model can be interpreted as a measure of microvascular RTK. With increasing blood flow,αdropped significantly, leading to an increase in RTK.Significance. The f1C model is a practical approach based on hemodynamic principles to quantify physiological microvascular perfusion but it is impaired due to its compartmental nature.
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Affiliation(s)
- Stefan Hindel
- Department of Radiotherapy, Medical Physics section, University Hospital Essen, Essen, North Rhine-Westphalia, Germany.,Faculty of Physics, Technische Universität Kaiserslautern, Kaiserslautern, Rhineland-Palatinate, Germany
| | - Lena Heuchel
- Faculty of Physics, Technische Universität Dortmund, Dortmund, North Rhine-Westphalia, Germany
| | - Lutz Lüdemann
- Department of Radiotherapy, Medical Physics section, University Hospital Essen, Essen, North Rhine-Westphalia, Germany
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Comparison of the Relaxivities of Macrocyclic Gadolinium-Based Contrast Agents in Human Plasma at 1.5, 3, and 7 T, and Blood at 3 T. Invest Radiol 2020; 54:559-564. [PMID: 31124800 DOI: 10.1097/rli.0000000000000577] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
PURPOSE The relaxivities of 3 macrocyclic gadolinium-based contrast agents (GBCAs) were determined in human plasma and blood under standardized and clinically relevant laboratory conditions. METHODS The T1 relaxivity, r1, was determined in human plasma at 1.5, 3, and 7 T, and in human blood at 3 T at 37°C in phantoms containing 4 different concentrations of the macrocyclic GBCAs gadobutrol, gadoteridol, and gadoterate. An inversion recovery turbo spin echo sequence was used to generate images with several inversion times. The T1-times were obtained by fitting the signal intensities to the signal equation. r1 was obtained by a 1/y-weighted regression of the T1-rates over the concentration of the GBCAs. RESULTS For gadobutrol, the obtained r1 [L/(mmol·s)] in human plasma at 1.5 T, 3 T, and 7 T, and in human blood at 3 T was 4.78 ± 0.12, 4.97 ± 0.59, 3.83 ± 0.24, and 3.47 ± 0.16. For gadoteridol, r1 was 3.80 ± 0.10, 3.28 ± 0.09, 3.21 ± 0.07, and 2.61 ± 0.16, and for gadoterate, 3.32 ± 0.13, 3.00 ± 0.13, 2.84 ± 0.09, and 2.72 ± 0.17. CONCLUSIONS The relaxivity of gadobutrol is significantly higher than that of gadoteridol and gadoterate at all magnetic field strengths and in plasma as well as in blood, whereas that of gadoteridol was higher than gadoterate only in plasma at 1.5 and 7 T. This is in accordance with results from 3 previous studies obtained in different media.
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Li H, Meade TJ. Molecular Magnetic Resonance Imaging with Gd(III)-Based Contrast Agents: Challenges and Key Advances. J Am Chem Soc 2019; 141:17025-17041. [PMID: 31593630 DOI: 10.1021/jacs.9b09149] [Citation(s) in RCA: 135] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In an era of personalized medicine, the clinical community has become increasingly focused on understanding diseases at the cellular and molecular levels. Magnetic resonance imaging (MRI) is a powerful imaging modality for acquiring anatomical and functional information. However, it has limited applications in the field of molecular imaging due to its low sensitivity. To expand the capability of MRI to encompass molecular imaging applications, we introduced bioresponsive Gd(III)-based magnetic resonance contrast agents (GBCAs) in 1997. Since that time, many research groups across the globe have developed new examples of bioresponsive GBCAs. These contrast agents have shown great promise for visualizing several biochemical processes, such as gene expression, neuronal signaling, and hormone secretion. They are designed to be conditionally retained, or activated, in vivo in response to specific biochemical events of interest. As a result, an observed MR signal change can serve as a read-out for molecular events. A significant challenge for these probes is how to utilize them for noninvasive diagnostic and theranostic applications. This Perspective focuses on the design strategies that underlie bioresponsive probes, and describes the key advances made in recent years that are facilitating their application in vivo and ultimately in clinical translation. While the field of bioresponsive agents is embryonic, it is clear that many solutions to the experimental and clinical radiologic problems of today will be overcome by the probes of tomorrow.
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Affiliation(s)
- Hao Li
- Departments of Chemistry, Molecular Biosciences, Neurobiology, and Radiology Northwestern University , Evanston , Illinois 60208 , United States
| | - Thomas J Meade
- Departments of Chemistry, Molecular Biosciences, Neurobiology, and Radiology Northwestern University , Evanston , Illinois 60208 , United States
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Advocating the Development of Next-Generation High-Relaxivity Gadolinium Chelates for Clinical Magnetic Resonance. Invest Radiol 2019; 53:381-389. [PMID: 29462023 DOI: 10.1097/rli.0000000000000454] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The question of improved relaxivity, and potential efficacy therein, for a next-generation of magnetic resonance gadolinium chelates with extracellular distribution and renal excretion, which could also be viewed from the perspective of dose, is addressed on the basis of historical development, animal experimentation, and human trials. There was no systematic evaluation that preceded the choice of 0.1 mmol/kg as the standard dose for human imaging with the gadolinium chelates. In part, this dose was chosen owing to bloodwork abnormalities seen in phase I and phase II studies. Animal investigations and early clinical trials demonstrated improved lesion detectability at higher doses in the brain, liver, and heart. By designing an agent with substantially improved relaxivity, higher enhancement equivalent to that provided with the conventional gadolinium agents at high dose could be achieved, translating to improved diagnosis and, thus, clinical care. Implicit in the development of such high-relaxivity agents would be stability equivalent to or exceeding that of the currently approved macrocyclic agents, given current concern regarding dechelation and gadolinium deposition in the brain, skin, and bone with the linear agents that were initially approved. Development of such next-generation agents with a substantial improvement in relaxivity, in comparison with the current group of approved agents, with a 2-fold increase likely achievable, could lead to improved lesion enhancement, characterization, diagnosis, and, thus, clinical efficacy.
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Urbanovský P, Kotek J, Carniato F, Botta M, Hermann P. Lanthanide Complexes of DO3A-(Dibenzylamino)methylphosphinate: Effect of Protonation of the Dibenzylamino Group on the Water-Exchange Rate and the Binding of Human Serum Albumin. Inorg Chem 2019; 58:5196-5210. [PMID: 30942072 DOI: 10.1021/acs.inorgchem.9b00267] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Protonation of a distant, noncoordinated group of metal-based magnetic resonance imaging contrast agents potentially changes their relaxivity. The effect of a positive charge of the drug on the human serum albumin (HSA)-drug interaction remains poorly understood as well. Accordingly, a (dibenzylamino)methylphosphinate derivative of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) was efficiently synthesized using pyridine as the solvent for a Mannich-type reaction of tBu3DO3A, formaldehyde, and Bn2NCH2PO2H2 ethyl ester. The ligand protonation and metal ion (Gd3+, Cu2+, and Zn2+) stability constants were similar to those of the parent DOTA, whereas the basicity of the side-chain amino group of the complexes (log KA = 5.8) was 1 order of magnitude lower than that of the free ligand (log KA = 6.8). The presence of one bound water molecule in both deprotonated and protonated forms of the gadolinium(III) complex was deduced from the solid-state X-ray diffraction data [gadolinium(III) and dysprosium(III)], from the square antiprism/twisted square antiprism (SA/TSA) isomer ratio along the lanthanide series, from the fluorescence data of the europium(III) complex, and from the 17O NMR measurements of the dysprosium(III) and gadolinium(III) complexes. In the gadolinium(III) complex with the deprotonated amino group, water exchange is extremely fast (τM = 6 ns at 25 °C), most likely thanks to the high abundance of the TSA isomer and to the presence of a proximate protonable group, which assists the water-exchange process. The interaction between lanthanide(III) complexes and HSA is pH-dependent, and the deprotonated form is bound much more efficaciously (∼13% and ∼70% bound complex at pH = 4 and 7, respectively). The relaxivities of the complex and its HSA adduct are also pH-dependent, and the latter is approximately 2-3 times increased at pH = 4-7. The relaxivity for the supramolecular HSA-complex adduct ( r1b) is as high as 52 mM-1 s-1 at neutral pH (at 20 MHz and 25 °C). The findings of this study stand as a proof-of-concept, showing the ability to manipulate an albumin-drug interaction, and thus the blood pool residence time of the drug, by introducing a positive charge in a side-chain amino group.
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Affiliation(s)
- Peter Urbanovský
- Department of Inorganic Chemistry , Universita Karlova (Charles University) , Hlavova 2030 , 12843 Prague 2 , Czech Republic
| | - Jan Kotek
- Department of Inorganic Chemistry , Universita Karlova (Charles University) , Hlavova 2030 , 12843 Prague 2 , Czech Republic
| | - Fabio Carniato
- Dipartimento di Scienze e Innovazione Tecnologica , Università del Piemonte Orientale "A. Avogadro" , Viale T. Michel 11 , 15121 Alessandria , Italy
| | - Mauro Botta
- Dipartimento di Scienze e Innovazione Tecnologica , Università del Piemonte Orientale "A. Avogadro" , Viale T. Michel 11 , 15121 Alessandria , Italy
| | - Petr Hermann
- Department of Inorganic Chemistry , Universita Karlova (Charles University) , Hlavova 2030 , 12843 Prague 2 , Czech Republic
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11
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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: 820] [Impact Index Per Article: 164.0] [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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12
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Montesi SB, Désogère P, Fuchs BC, Caravan P. Molecular imaging of fibrosis: recent advances and future directions. J Clin Invest 2019; 129:24-33. [PMID: 30601139 DOI: 10.1172/jci122132] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Fibrosis, the progressive accumulation of connective tissue that occurs in response to injury, causes irreparable organ damage and may result in organ failure. The few available antifibrotic treatments modify the rate of fibrosis progression, but there are no available treatments to reverse established fibrosis. Thus, more effective therapies are urgently needed. Molecular imaging is a promising biomedical methodology that enables noninvasive visualization of cellular and subcellular processes. It provides a unique means to monitor and quantify dysregulated molecular fibrotic pathways in a noninvasive manner. Molecular imaging could be used for early detection, disease staging, and prognostication, as well as for assessing disease activity and treatment response. As fibrotic diseases are often molecularly heterogeneous, molecular imaging of a specific pathway could be used for patient stratification and cohort enrichment with the goal of improving clinical trial design and feasibility and increasing the ability to detect a definitive outcome for new therapies. Here we review currently available molecular imaging probes for detecting fibrosis and fibrogenesis, the active formation of new fibrous tissue, and their application to models of fibrosis across organ systems and fibrotic processes. We provide our opinion as to the potential roles of molecular imaging in human fibrotic diseases.
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Affiliation(s)
| | - Pauline Désogère
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA.,Athinoula A. Martinos Center for Biomedical Imaging and.,Institute for Innovation in Imaging, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Bryan C Fuchs
- Division of Surgical Oncology, Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Peter Caravan
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA.,Athinoula A. Martinos Center for Biomedical Imaging and.,Institute for Innovation in Imaging, Massachusetts General Hospital, Boston, Massachusetts, USA
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13
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Caravan P, Esteban-Gómez D, Rodríguez-Rodríguez A, Platas-Iglesias C. Water exchange in lanthanide complexes for MRI applications. Lessons learned over the last 25 years. Dalton Trans 2019; 48:11161-11180. [DOI: 10.1039/c9dt01948k] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Coordination chemistry offers convenient strategies to modulate the exchange of coordinated water molecules in lanthanide-based contrast agents.
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Affiliation(s)
- Peter Caravan
- The Institute for Innovation in Imaging and the A. A. Martinos Center for Biomedical Imaging
- Massachusetts General Hospital
- Harvard Medical School
- Charlestown
- USA
| | - David Esteban-Gómez
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química
- Universidade da Coruña
- 15008 A Coruña
- Spain
| | - Aurora Rodríguez-Rodríguez
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química
- Universidade da Coruña
- 15008 A Coruña
- Spain
| | - Carlos Platas-Iglesias
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química
- Universidade da Coruña
- 15008 A Coruña
- Spain
- The Institute for Innovation in Imaging and the A. A. Martinos Center for Biomedical Imaging
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Lavin B, Protti A, Lorrio S, Dong X, Phinikaridou A, Botnar RM, Shah A. MRI with gadofosveset: A potential marker for permeability in myocardial infarction. Atherosclerosis 2018; 275:400-408. [PMID: 29735362 PMCID: PMC6100880 DOI: 10.1016/j.atherosclerosis.2018.04.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 03/27/2018] [Accepted: 04/18/2018] [Indexed: 12/23/2022]
Abstract
BACKGROUND AND AIMS Acute ischemia is associated with myocardial endothelial damage and microvessel formation, resulting in leakage of plasma albumin into the myocardial extravascular space. In this study, we tested whether an albumin-binding intravascular contrast agent (gadofosveset) allows for improved quantification of myocardial permeability compared to the conventional extracellular contrast agent Gd-DTPA using late gadolinium enhancement (LGE) and T1 mapping in vivo. METHODS MI was induced in C57BL/6 mice (n = 6) and cardiac magnetic resonance imaging (CMR) was performed at 3, 10 and 21 days post-MI using Gd-DTPA and 24 h later using gadofosveset. Functional, LGE and T1 mapping protocols were performed 45 min post-injection of the contrast agent. RESULTS LGE images showed that both contrast agents provided similar measurements of infarct area at all time points following MI. Importantly, the myocardial R1 measurements after administration of gadofosveset were higher in the acute phase-day 3 (R1 [s-1] = 6.29 ± 0.29) compared to the maturation phase-days 10 and 21 (R1 [s-1] = 4.76 ± 0.30 and 4.48 ± 0.14), suggesting that the uptake of this agent could be used to stage myocardial remodeling. No differences in myocardial R1 were observed after administration of Gd-DTPA at different time points post-MI (R1 [s-1] = 3d: 3.77 ± 0.37; 10d: 2.74 ± 0.06; 21d: 3.35 ± 0.26). The MRI results were validated by ex vivo histology that showed albumin leakage in the myocardium in the acute phase and microvessel formation at later stages. CONCLUSIONS We demonstrate the merits of an albumin-binding contrast agent for monitoring changes in myocardial permeability between acute ischemia and chronic post-MI myocardial remodeling.
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Affiliation(s)
- Begoña Lavin
- School of Biomedical Engineering Imaging Sciences, King's College London, London, UK; The British Heart Foundation Centre of Excellence, Cardiovascular Division, King's College London, London, United Kingdom.
| | - Andrea Protti
- School of Biomedical Engineering Imaging Sciences, King's College London, London, UK; The British Heart Foundation Centre of Excellence, Cardiovascular Division, King's College London, London, United Kingdom; Cardiovascular Division, James Black Centre, King's College Hospital Denmark Hill London, London, SE5 9NU, United Kingdom
| | - Silvia Lorrio
- School of Biomedical Engineering Imaging Sciences, King's College London, London, UK; The British Heart Foundation Centre of Excellence, Cardiovascular Division, King's College London, London, United Kingdom
| | - Xuebin Dong
- Cardiovascular Division, James Black Centre, King's College Hospital Denmark Hill London, London, SE5 9NU, United Kingdom
| | - Alkystis Phinikaridou
- School of Biomedical Engineering Imaging Sciences, King's College London, London, UK; The British Heart Foundation Centre of Excellence, Cardiovascular Division, King's College London, London, United Kingdom
| | - René M Botnar
- School of Biomedical Engineering Imaging Sciences, King's College London, London, UK; The British Heart Foundation Centre of Excellence, Cardiovascular Division, King's College London, London, United Kingdom; Pontificia Universidad Católica de Chile, Escuela de Ingeniería, Santiago, Chile
| | - Ajay Shah
- The British Heart Foundation Centre of Excellence, Cardiovascular Division, King's College London, London, United Kingdom; Cardiovascular Division, James Black Centre, King's College Hospital Denmark Hill London, London, SE5 9NU, United Kingdom
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15
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Montesi SB, Rao R, Liang LL, Goulart HE, Sharma A, Digumarthy SR, Shea BS, Seethamraju RT, Caravan P, Tager AM. Gadofosveset-enhanced lung magnetic resonance imaging to detect ongoing vascular leak in pulmonary fibrosis. Eur Respir J 2018; 51:13993003.00171-2018. [PMID: 29622569 DOI: 10.1183/13993003.00171-2018] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 03/06/2018] [Indexed: 01/17/2023]
Affiliation(s)
- Sydney B Montesi
- Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Rohan Rao
- Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Lloyd L Liang
- Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Hannah E Goulart
- Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Amita Sharma
- Dept of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Subba R Digumarthy
- Dept of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Barry S Shea
- Division of Pulmonary, Critical Care and Sleep Medicine, Albert Medical School of Brown University, Providence, RI, USA
| | - Ravi T Seethamraju
- Siemens Healthcare, Boston, MA, USA.,Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
| | - Peter Caravan
- Dept of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.,Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA.,Institute for Innovation in Imaging, Massachusetts General Hospital, Charlestown, MA, USA
| | - Andrew M Tager
- Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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Araya YT, Martínez-Santiesteban F, Handler WB, Harris CT, Chronik BA, Scholl TJ. Nuclear magnetic relaxation dispersion of murine tissue for development of T 1 (R 1 ) dispersion contrast imaging. NMR IN BIOMEDICINE 2017; 30:e3789. [PMID: 29044888 DOI: 10.1002/nbm.3789] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 07/18/2017] [Accepted: 07/19/2017] [Indexed: 06/07/2023]
Abstract
This study quantified the spin-lattice relaxation rate (R1 ) dispersion of murine tissues from 0.24 mT to 3 T. A combination of ex vivo and in vivo spin-lattice relaxation rate measurements were acquired for murine tissue. Selected brain, liver, kidney, muscle, and fat tissues were excised and R1 dispersion profiles were acquired from 0.24 mT to 1.0 T at 37 °C, using a fast field-cycling MR (FFC-MR) relaxometer. In vivo R1 dispersion profiles of mice were acquired from 1.26 T to 1.74 T at 37 °C, using FFC-MRI on a 1.5 T scanner outfitted with a field-cycling insert electromagnet to dynamically control B0 prior to imaging. Images at five field strengths (1.26, 1.39, 1.5, 1.61, 1.74 T) were acquired using a field-cycling pulse sequence, where B0 was modulated for varying relaxation durations prior to imaging. R1 maps and R1 dispersion (ΔR1 /ΔB0 ) were calculated at 1.5 T on a pixel-by-pixel basis. In addition, in vivo R1 maps of mice were acquired at 3 T. At fields less than 1 T, a large R1 magnetic field dependence was observed for tissues. ROI analysis of the tissues showed little relaxation dispersion for magnetic fields from 1.26 T to 3 T. Our tissue measurements show strong R1 dispersion at field strengths less than 1 T and limited R1 dispersion at field strengths greater than 1 T. These findings emphasize the inherent weak R1 magnetic field dependence of healthy tissues at clinical field strengths. This characteristic of tissues can be exploited by a combination of FFC-MRI and T1 contrast agents that exhibit strong relaxivity magnetic field dependences (inherent or by binding to a protein), thereby increasing the agents' specificity and sensitivity. This development can provide potential insights into protein-based biomarkers using FFC-MRI to assess early changes in tumour development, which are not easily measureable with conventional MRI.
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Affiliation(s)
- Yonathan T Araya
- Department of Medical Biophysics, Western University, London, ON, Canada
| | | | - William B Handler
- Department of Physics and Astronomy, Western University, London, ON, Canada
| | - Chad T Harris
- Department of Physics and Astronomy, Western University, London, ON, Canada
| | - Blaine A Chronik
- Department of Physics and Astronomy, Western University, London, ON, Canada
| | - Timothy J Scholl
- Department of Medical Biophysics, Western University, London, ON, Canada
- Imaging Research Laboratories, Robarts Research Institute, London, ON, Canada
- Ontario Institute for Cancer Research, Toronto, ON, Canada
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17
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Ghaghada KB, Starosolski ZA, Bhayana S, Stupin I, Patel CV, Bhavane RC, Gao H, Bednov A, Yallampalli C, Belfort M, George V, Annapragada AV. Pre-clinical evaluation of a nanoparticle-based blood-pool contrast agent for MR imaging of the placenta. Placenta 2017; 57:60-70. [DOI: 10.1016/j.placenta.2017.06.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 05/03/2017] [Accepted: 06/12/2017] [Indexed: 12/21/2022]
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18
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Hindel S, Söhner A, Maaß M, Sauerwein W, Möllmann D, Baba HA, Kramer M, Lüdemann L. Validation of Blood Volume Fraction Quantification with 3D Gradient Echo Dynamic Contrast-Enhanced Magnetic Resonance Imaging in Porcine Skeletal Muscle. PLoS One 2017; 12:e0170841. [PMID: 28141810 PMCID: PMC5283669 DOI: 10.1371/journal.pone.0170841] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 01/11/2017] [Indexed: 12/16/2022] Open
Abstract
The purpose of this study was to assess the accuracy of fractional blood volume (vb) estimates in low-perfused and low-vascularized tissue using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). The results of different MRI methods were compared with histology to evaluate the accuracy of these methods under clinical conditions. vb was estimated by DCE-MRI using a 3D gradient echo sequence with k-space undersampling in five muscle groups in the hind leg of 9 female pigs. Two gadolinium-based contrast agents (CA) were used: a rapidly extravasating, extracellular, gadolinium-based, low-molecular-weight contrast agent (LMCA, gadoterate meglumine) and an extracellular, gadolinium-based, albumin-binding, slowly extravasating blood pool contrast agent (BPCA, gadofosveset trisodium). LMCA data were evaluated using the extended Tofts model (ETM) and the two-compartment exchange model (2CXM). The images acquired with administration of the BPCA were used to evaluate the accuracy of vb estimation with a bolus deconvolution technique (BD) and a method we call equilibrium MRI (EqMRI). The latter calculates the ratio of the magnitude of the relaxation rate change in the tissue curve at an approximate equilibrium state to the height of the same area of the arterial input function (AIF). Immunohistochemical staining with isolectin was used to label endothelium. A light microscope was used to estimate the fractional vascular area by relating the vascular region to the total tissue region (immunohistochemical vessel staining, IHVS). In addition, the percentage fraction of vascular volume was determined by multiplying the microvascular density (MVD) with the average estimated capillary lumen, π(d2)2, where d = 8μm is the assumed capillary diameter (microvascular density estimation, MVDE). Except for ETM values, highly significant correlations were found between most of the MRI methods investigated. In the cranial thigh, for example, the vb medians (interquartile range, IQRs) of IHVS, MVDE, BD, EqMRI, 2CXM and ETM were vb = 0.7(0.3)%, 1.1(0.4)%, 1.1(0.4)%, 1.4(0.3)%, 1.2(1.8)% and 0.1(0.2)%, respectively. Variances, expressed by the difference between third and first quartiles (IQR) were highest for the 2CXM for all muscle groups. High correlations between the values in four muscle groups—medial, cranial, lateral thigh and lower leg - estimated with MRI and histology were found between BD and EqMRI, MVDE and 2CXM and IHVS and ETM. Except for the ETM, no significant differences between the vb medians of all MRI methods were revealed with the Wilcoxon rank sum test. The same holds for all muscle regions using the 2CXM and MVDE. Except for cranial thigh muscle, no significant difference was found between EqMRI and MVDE. And except for the cranial thigh and the lower leg muscle, there was also no significant difference between the vb medians of BD and MVDE. Overall, there was good vb agreement between histology and the BPCA MRI methods and the 2CXM LMCA approach with the exception of the ETM method. Although LMCA models have the advantage of providing excellent curve fits and can in principle determine more physiological parameters than BPCA methods, they yield more inaccurate results.
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Affiliation(s)
- Stefan Hindel
- Department of Radiotherapy, Medical Physics, University Hospital Essen, Essen, North Rhine-Westphalia, Germany
- * E-mail:
| | - Anika Söhner
- Department of Radiotherapy, Medical Physics, University Hospital Essen, Essen, North Rhine-Westphalia, Germany
| | - Marc Maaß
- Department of General and Visceral Surgery at Evangelical Hospital Wesel, Wesel, North Rhine-Westphalia, Germany
| | - Wolfgang Sauerwein
- Department of Radiotherapy, Medical Physics, University Hospital Essen, Essen, North Rhine-Westphalia, Germany
| | - Dorothe Möllmann
- Department of Pathology, University Hospital Essen, Essen, North Rhine-Westphalia, Germany
| | - Hideo Andreas Baba
- Department of Pathology, University Hospital Essen, Essen, North Rhine-Westphalia, Germany
| | - Martin Kramer
- Hospital of Veterinary Medicine, Department of Small Animal Surgery, Justus Liebig University Giessen, Giessen, Hesse, Germany
| | - Lutz Lüdemann
- Department of Radiotherapy, Medical Physics, University Hospital Essen, Essen, North Rhine-Westphalia, Germany
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19
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Shuvaev S, Pal R, Parker D. Selectively switching on europium emission in drug site one of human serum albumin. Chem Commun (Camb) 2017; 53:6724-6727. [DOI: 10.1039/c7cc03071a] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A luminescent europium probe has been discovered that binds selectively to drug-site I in human serum albumin, signalled by a ‘switching on’ of europium emission, and accompanied by strong induced circularly polarised luminescence.
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Affiliation(s)
- Sergey Shuvaev
- Department of Chemistry
- Durham University
- Durham DH1 3LE
- UK
| | - Robert Pal
- Department of Chemistry
- Durham University
- Durham DH1 3LE
- UK
| | - David Parker
- Department of Chemistry
- Durham University
- Durham DH1 3LE
- UK
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20
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Agostini A, Kircher MF, Do R, Borgheresi A, Monti S, Giovagnoni A, Mannelli L. Magnetic Resonance Imaging of the Liver (Including Biliary Contrast Agents) Part 1: Technical Considerations and Contrast Materials. Semin Roentgenol 2016; 51:308-316. [PMID: 27743567 DOI: 10.1053/j.ro.2016.05.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- A Agostini
- Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY; Department of Radiology, School of Radiology, Universita' Politecnica delle Marche Ancona, Italy
| | - M F Kircher
- Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY
| | - R Do
- Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY
| | - A Borgheresi
- Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY; Department of Radiology, School of Radiology, Universita' degli Studi di Firenze Firenze, Italy
| | | | - A Giovagnoni
- Department of Radiology, School of Radiology, Universita' Politecnica delle Marche Ancona, Italy
| | - L Mannelli
- Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY.
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21
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Longo DL, Arena F, Consolino L, Minazzi P, Geninatti-Crich S, Giovenzana GB, Aime S. Gd-AAZTA-MADEC, an improved blood pool agent for DCE-MRI studies on mice on 1 T scanners. Biomaterials 2015; 75:47-57. [PMID: 26480471 DOI: 10.1016/j.biomaterials.2015.10.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 09/30/2015] [Accepted: 10/05/2015] [Indexed: 10/22/2022]
Abstract
A novel MRI blood-pool contrast agent (Gd-AAZTA-MADEC) has been compared with established blood pool agents for tumor contrast enhanced images and angiography. Synthesis, relaxometric properties, albumin binding affinity and pharmacokinetic profiles are reported. For in vivo studies, angiographic images and tumor contrast enhanced images were acquired on mice with benchtop 1T-MRI scanners and compared with MS-325, B22956/1 and B25716/1. The design of this contrast agent involved the elongation of the spacer between the targeting deoxycholic acid moiety and the Gd-AAZTA imaging reporting unit that drastically changed either the binding affinity to albumin (KA(HSA) = 8.3 × 10(5) M(-1)) and the hydration state of the Gd ion (q = 2) in comparison to the recently reported B25716/1. The very markedly high binding affinity towards mouse and human serum albumins resulted in peculiar pharmacokinetics and relaxometric properties. The NMRD profiles clearly indicated that maximum efficiency is attainable at magnetic field strength of 1 T. In vivo studies showed high enhancement of the vasculature and a prolonged accumulation inside tumor. The herein reported pre-clinical imaging studies show that a great benefit arises from the combination of a benchtop MRI scanner operating at 1 T and the albumin-binding Gd-AAZTA-MADEC complex, for pursuing enhanced angiography and improved characterization of tumor vascular microenvironment.
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Affiliation(s)
- Dario Livio Longo
- Istituto di Biostrutture e Bioimmagini (CNR) c/o Molecular Biotechnology Center, Via Nizza 52, 10126, Torino, Italy; Molecular Imaging Center, University of Torino, Via Nizza 52, 10126, Torino, Italy.
| | - Francesca Arena
- Molecular Imaging Center, University of Torino, Via Nizza 52, 10126, Torino, Italy; Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126, Torino, Italy
| | - Lorena Consolino
- Molecular Imaging Center, University of Torino, Via Nizza 52, 10126, Torino, Italy; Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126, Torino, Italy; CAGE Chemicals Srl, Via Bovio 6, 28100, Novara, Italy
| | - Paolo Minazzi
- Dipartimento di Scienze del Farmaco, Università del Piemonte Orientale "A. Avogadro" Largo Donegani 2/3, 28100, Novara, Italy; CAGE Chemicals Srl, Via Bovio 6, 28100, Novara, Italy
| | - Simonetta Geninatti-Crich
- Molecular Imaging Center, University of Torino, Via Nizza 52, 10126, Torino, Italy; Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126, Torino, Italy
| | - Giovanni Battista Giovenzana
- Dipartimento di Scienze del Farmaco, Università del Piemonte Orientale "A. Avogadro" Largo Donegani 2/3, 28100, Novara, Italy; CAGE Chemicals Srl, Via Bovio 6, 28100, Novara, Italy
| | - Silvio Aime
- Istituto di Biostrutture e Bioimmagini (CNR) c/o Molecular Biotechnology Center, Via Nizza 52, 10126, Torino, Italy; Molecular Imaging Center, University of Torino, Via Nizza 52, 10126, Torino, Italy; Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126, Torino, Italy
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22
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Bakermans AJ, Abdurrachim D, Moonen RPM, Motaal AG, Prompers JJ, Strijkers GJ, Vandoorne K, Nicolay K. Small animal cardiovascular MR imaging and spectroscopy. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2015; 88-89:1-47. [PMID: 26282195 DOI: 10.1016/j.pnmrs.2015.03.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 03/09/2015] [Accepted: 03/09/2015] [Indexed: 06/04/2023]
Abstract
The use of MR imaging and spectroscopy for studying cardiovascular disease processes in small animals has increased tremendously over the past decade. This is the result of the remarkable advances in MR technologies and the increased availability of genetically modified mice. MR techniques provide a window on the entire timeline of cardiovascular disease development, ranging from subtle early changes in myocardial metabolism that often mark disease onset to severe myocardial dysfunction associated with end-stage heart failure. MR imaging and spectroscopy techniques play an important role in basic cardiovascular research and in cardiovascular disease diagnosis and therapy follow-up. This is due to the broad range of functional, structural and metabolic parameters that can be quantified by MR under in vivo conditions non-invasively. This review describes the spectrum of MR techniques that are employed in small animal cardiovascular disease research and how the technological challenges resulting from the small dimensions of heart and blood vessels as well as high heart and respiratory rates, particularly in mice, are tackled.
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Affiliation(s)
- Adrianus J Bakermans
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Desiree Abdurrachim
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Rik P M Moonen
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Abdallah G Motaal
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Jeanine J Prompers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Gustav J Strijkers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Katrien Vandoorne
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Klaas Nicolay
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
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23
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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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24
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Richardson OC, Bane O, Scott MLJ, Tanner SF, Waterton JC, Sourbron SP, Carroll TJ, Buckley DL. Gadofosveset-based biomarker of tissue albumin concentration: Technical validation in vitro and feasibility in vivo. Magn Reson Med 2015; 73:244-53. [PMID: 24515975 PMCID: PMC4296221 DOI: 10.1002/mrm.25128] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 12/19/2013] [Indexed: 11/07/2022]
Abstract
PURPOSE There is currently no adequate method of mapping physiologic and pathophysiologic tissue albumin concentrations in human subjects. The objective of this study was to devise and evaluate a biomarker of regional albumin concentration using gadofosveset-enhanced MRI. THEORY AND METHODS A binding and relaxation model was devised and evaluated in vitro in solutions of albumin at 3.0 Tesla (T) and 4.7T. The method was evaluated in the heart in seven volunteers at 3.0T. RESULTS MRI-derived estimates of albumin concentration were in good agreement with true values over the range 0.1-1.0 mM (Pearson correlation coefficients of 0.85 and 0.88 for 3.0T and 4.7T, respectively). The mean calculated albumin concentration in the myocardium for the volunteers was 0.02 mM (range, 0.01-0.03 mM). CONCLUSION Accurate estimates of albumin concentration in vitro suggest this may be a viable noninvasive alternative to existing techniques. In the myocardium the MRI-derived estimates of albumin concentration indicate the practical feasibility of the technique but were below expected values. Gadofosveset-enhanced MR relaxometry has potential in providing biomarkers of regional albumin concentration; further evaluation is required before it can be used reliably in vivo.
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Affiliation(s)
- Owen C Richardson
- Division of Medical Physics, University of LeedsLeeds, United Kingdom
| | - Octavia Bane
- Departments of Biomedical Engineering and Radiology, Northwestern UniversityChicago, Illinois, USA
| | - Marietta LJ Scott
- Personalized Healthcare and Biomarkers, AstraZenecaMacclesfield, Cheshire, United Kingdom
| | - Steven F Tanner
- Department of Medical Physics and Engineering, Leeds Teaching Hospitals NHS TrustLeeds, United Kingdom.
| | - John C Waterton
- Personalized Healthcare and Biomarkers, AstraZenecaMacclesfield, Cheshire, United Kingdom
| | - Steven P Sourbron
- Division of Medical Physics, University of LeedsLeeds, United Kingdom
| | - Timothy J Carroll
- Departments of Biomedical Engineering and Radiology, Northwestern UniversityChicago, Illinois, USA
| | - David L Buckley
- Division of Medical Physics, University of LeedsLeeds, United Kingdom
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25
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Morrison DE, Aitken JB, de Jonge MD, Issa F, Harris HH, Rendina LM. Synthesis and Biological Evaluation of a Class of Mitochondrially-Targeted Gadolinium(III) Agents. Chemistry 2014; 20:16602-12. [DOI: 10.1002/chem.201404107] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Indexed: 11/10/2022]
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26
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Xie L, Subashi E, Qi Y, Knepper MA, Johnson GA. Four-dimensional MRI of renal function in the developing mouse. NMR IN BIOMEDICINE 2014; 27:1094-102. [PMID: 25066408 PMCID: PMC4134394 DOI: 10.1002/nbm.3162] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 06/13/2014] [Accepted: 06/22/2014] [Indexed: 05/02/2023]
Abstract
The major roles of filtration, metabolism and high blood flow make the kidney highly vulnerable to drug-induced toxicity and other renal injuries. A method to follow kidney function is essential for the early screening of toxicity and malformations. In this study, we acquired high spatiotemporal resolution (four dimensional) datasets of normal mice to follow changes in kidney structure and function during development. The data were acquired with dynamic contrast-enhanced MRI (via keyhole imaging) and a cryogenic surface coil, allowing us to obtain a full three-dimensional image (isotropic resolution, 125 microns) every 7.7 s over a 50-min scan. This time course permitted the demonstration of both contrast enhancement and clearance. Functional changes were measured over a 17-week course (at 3, 5, 7, 9, 13 and 17 weeks). The time dimension of the MRI dataset was processed to produce unique image contrasts to segment the four regions of the kidney: cortex (CO), outer stripe (OS) of the outer medulla (OM), inner stripe (IS) of the OM and inner medulla (IM). Local volumes, time-to-peak (TTP) values and decay constants (DC) were measured in each renal region. These metrics increased significantly with age, with the exception of DC values in the IS and OS. These data will serve as a foundation for studies of normal renal physiology and future studies of renal diseases that require early detection and intervention.
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Affiliation(s)
- Luke Xie
- Center for In Vivo Microscopy, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, 27708
| | - Ergys Subashi
- Center for In Vivo Microscopy, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710
- Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina, 27710
| | - Yi Qi
- Center for In Vivo Microscopy, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710
| | - Mark A. Knepper
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, 20892-1603
| | - G. Allan Johnson
- Center for In Vivo Microscopy, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, 27708
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A novel gadolinium-based trimetasphere metallofullerene for application as a magnetic resonance imaging contrast agent. Invest Radiol 2014; 48:745-54. [PMID: 23748228 DOI: 10.1097/rli.0b013e318294de5d] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Macromolecular contrast agents for magnetic resonance imaging (MRI) are useful blood-pool agents because of their long systemic half-life and have found applications in monitoring tumor vasculature and angiogenesis. Macromolecular contrast agents have been able to overcome some of the disadvantages of the conventional small-molecule contrast agent Magnevist (gadolinium-diethylenetriaminepentaacetic acid), such as rapid extravasation and quick renal clearance, which limits the viable MRI time. There is an urgent need for new MRI contrast agents that increase the sensitivity of detection with a higher relaxivity, longer blood half-life, and reduced toxicity from free Gd3+ ions. Here, we report on the characterization of a novel water-soluble, derivatized, gadolinium-enclosed metallofullerene nanoparticle (Hydrochalarone-1) in development as an MRI contrast agent. MATERIALS AND METHODS The physicochemical properties of Hydrochalarone-1 were characterized by dynamic light scattering (hydrodynamic diameter), atomic force microscopy (particle height), ζ potential analysis (surface charge), and inductively coupled plasma-mass spectrometry (gadolinium concentration). The blood compatibility of Hydrochalarone-1 was also assessed in vitro through analysis of hemolysis, platelet aggregation, and complement activation of human blood. In vitro relaxivities, in vivo pharmacokinetics, and a pilot in vivo acute toxicity study were also performed. RESULTS An extensive in vitro and in vivo characterization of Hydrochalarone-1 is described here. The hydrodynamic size of Hydrochalarone-1 was 5 to 7 nm depending on the dispersing media, and it was negatively charged at physiological pH. Hydrochalarone-1 showed compatibility with blood cells in vitro, and no significant hemolysis, platelet aggregation, or complement activation was observed in vitro. In addition, Hydrochalarone-1 had significantly higher r1 and r2 in vitro relaxivities in human plasma in comparison with Magnevist and was not toxic at the doses administered in an in vivo pilot acute-dose toxicity study in mice.In vivo MRI pharmacokinetic analysis after a single intravenous injection of Hydrochalarone-1 (0.2 mmol Gd/kg) showed that the volume of distribution at steady state was approximately 100 mL/kg, suggesting prolonged systemic circulation. Hydrochalarone-1 also had a long blood half-life (88 minutes) and increased relaxivity, suggesting application as a promising blood-pool MRI contrast agent. CONCLUSIONS The evidence suggests that Hydrochalarone-1, with its long systemic half-life, may have significant utility as a blood-pool MRI contrast agent.
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Chwang WB, Jain R, Bagher-Ebadian H, Nejad-Davarani SP, Iskander ASM, VanSlooten A, Schultz L, Arbab AS, Ewing JR. Measurement of rat brain tumor kinetics using an intravascular MR contrast agent and DCE-MRI nested model selection. J Magn Reson Imaging 2014; 40:1223-9. [PMID: 24421265 DOI: 10.1002/jmri.24469] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 09/17/2013] [Indexed: 11/11/2022] Open
Abstract
PURPOSE Using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in a rat glioma model, and nested model selection (NMS), to compare estimates of the pharmacokinetic parameters vp , K(trans) , and ve for two different contrast agents (CAs)-gadofosveset, which reversibly binds to human serum albumin, and gadopentetate dimeglumine, which does not. MATERIALS AND METHODS DCE-MRI studies were performed on nine Fisher 344 rats inoculated intracerebrally with 9L gliosarcoma cells using both gadofosveset and gadopentetate. The parameters vp , K(trans) , and ve were estimated using NMS. RESULTS K(trans) estimates using gadofosveset, compared to gadopentetate, differed in their means (gadofosveset 0.025 ± 0.008 min(-1) vs. gadopentetate 0.046 ± 0.011 min(-1) ; P = 0.0039). This difference notwithstanding, the intraclass correlation coefficient (ICC) for the two estimates of K(trans) showed nearly perfect linear dependence (ICC = 0.8479 by Pearson's r). Other estimates, ve (gadofosveset 22.7 ± 4.7% vs. gadopentetate 23.6 ± 5.6%; P = 0.4258) and vp (gadofosveset 1.5 ± 0.5% vs. gadopentetate 1.6 ± 0.4%; P = 0.25), were not different in their means between the two CAs, and there was almost perfect agreement for ve (ICC = 0.8798) and substantial agreement for vp (ICC = 0.7981) between the two CAs. CONCLUSION Estimates of K(trans) were statistically different using gadofosveset and gadopentetate, whereas ve and vp were similar with two CAs. NMS produced robust estimates of pharmacokinetic parameters using DCE-MRI that show promise as important measures of tumor physiology and microenvironment.
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Affiliation(s)
- Wilson B Chwang
- Department of Radiology, Henry Ford Hospital, Detroit, Michigan, USA
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Binding of a dimeric manganese porphyrin to serum albumin: towards a gadolinium-free blood-pool T
1 MRI contrast agent. J Biol Inorg Chem 2014; 19:229-35. [DOI: 10.1007/s00775-013-1073-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 12/05/2013] [Indexed: 10/25/2022]
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Bane O, Lee DC, Benefield BC, Harris KR, Chatterjee NR, Carr JC, Carroll TJ. Leakage and water exchange characterization of gadofosveset in the myocardium. Magn Reson Imaging 2013; 32:224-35. [PMID: 24418327 DOI: 10.1016/j.mri.2013.10.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 08/02/2013] [Accepted: 10/22/2013] [Indexed: 11/17/2022]
Abstract
PURPOSE To determine the compartmentalization of the blood pool agent gadofosveset and the effect of its transient binding to albumin on the quantification of steady-state fractional myocardial blood volume (fMBV). METHODS Myocardial vascular fraction measurements were simulated assuming the limiting cases (slow or fast) of two-compartment water exchange for different contrast agent injection concentrations, binding fractions, bound and free relaxivities, and true cardiac vascular fractions. fMBV was measured in five healthy volunteers (4 males, 1 female, average age 33) at 1.5T after administration of five injections of gadofosveset. The measurements in the volunteers were retrospectively compared to measurements of fMBV after three serial injections of the ultra-small, paramagnetic iron oxide (USPIO) blood pool agent ferumoxytol in an experimental animal. The true fMBV and exchange rate of water protons in both human and animal data sets was determined by chi square minimization. RESULTS Simulations showed an error in the measurement of fMBV due to partial binding of gadofosveset of less than 30%. Measured fMBV values over-estimate simulation predictions, and approach cardiac extracellular volume (22%), which suggests that the intravascular assumption may not be appropriate for the myocardium, although it may apply to more distal perfusion beds. In comparison, fMBV measured with ferumoxytol (5%, with slow water proton exchange across vascular wall) agree with published values of myocardial vascular fraction. Further comparison between myocardium relaxation rates induced by gadofosveset and by other extracellular and intravascular contrast agents showed that gadofosveset behaves like an extracellular contrast agent. CONCLUSIONS The distribution of the volunteer data indicates that a three-compartment model, with slow water exchange of gadofosveset and water protons between the vascular and interstitial compartments, and fast water exchange between the interstitium and the myocytes, is appropriate. The ferumoxytol measurements indicate that this USPIO is an intravascular contrast agent that can be used to quantify myocardial blood volume, with the appropriate correction for water exchange using a two-compartment water exchange model.
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Affiliation(s)
- Octavia Bane
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai Hospital, New York, NY, USA; Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA; Department of Radiology, Northwestern University, Chicago, IL, USA
| | - Daniel C Lee
- Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | | | - Kathleen R Harris
- Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Neil R Chatterjee
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA; Feinberg School of Medicine, Northwestern University, Chicago, IL, USA; Department of Radiology, Northwestern University, Chicago, IL, USA
| | - James C Carr
- Feinberg School of Medicine, Northwestern University, Chicago, IL, USA; Department of Radiology, Northwestern University, Chicago, IL, USA
| | - Timothy J Carroll
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA; Department of Radiology, Northwestern University, Chicago, IL, USA.
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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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Habets J, Zandvoort HJA, Reitsma JB, Bartels LW, Moll FL, Leiner T, van Herwaarden JA. Magnetic resonance imaging is more sensitive than computed tomography angiography for the detection of endoleaks after endovascular abdominal aortic aneurysm repair: a systematic review. Eur J Vasc Endovasc Surg 2013; 45:340-50. [PMID: 23403221 DOI: 10.1016/j.ejvs.2012.12.014] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 12/21/2012] [Indexed: 12/14/2022]
Abstract
OBJECTIVES The purpose of this systematic review was to examine whether magnetic resonance imaging (MRI) or computed tomography angiography (CTA) is more sensitive for the detection of endoleaks in patients with abdominal aortic aneurysm (AAA) after EVAR. DESIGN Systematic review. MATERIALS AND METHODS A systematic electronic search was performed. Articles were included when post-EVAR patients were evaluated by both MRI as index test and CTA as comparison. Methodological quality was assessed with the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool. Primary outcome was the proportion of patients in whom MRI detected additional endoleaks, which were not seen with CTA. RESULTS Eleven articles were included. The overall methodological quality of the articles was good. In total, 369 patients with 562 MRI and 562 CTA examinations were included. A total of 146 endoleaks were detected by CTA; MRI detected all but two of these endoleaks. With MRI 132 additional endoleaks were found. CONCLUSIONS MRI is more sensitive compared to CTA for the detection of post-EVAR endoleaks, especially for the detection of type II endoleaks. MRI should be considered in patients with continued AAA growth and negative or uncertain findings at CTA.
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Affiliation(s)
- J Habets
- Department of Radiology, University Medical Center Utrecht, Heidelberglaan 100, HP E01.132, 3508 GA Utrecht, The Netherlands.
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Sosnovik DE, Caravan P. Molecular MRI of the Cardiovascular System in the Post-NSF Era. CURRENT CARDIOVASCULAR IMAGING REPORTS 2012; 6:61-68. [PMID: 23504765 DOI: 10.1007/s12410-012-9182-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two new molecular MRI agents have been approved for clinical use within the last 3 years, and a third agent has completed phase-2 clinical trials. A wealth of preclinical data is also emerging on the general safety of many molecular MR imaging agents. In addition, since the guidelines to avoid nephrogenic systemic fibrosis (NSF) were adopted, at most institutions no new cases of NSF have been reported. Nevertheless, in the post-NSF environment, both those developing and using molecular MR imaging agents need to be increasingly aware of safety issues. This awareness should begin with the design of the agent and, even in early preclinical studies, the demonstration of safety and efficacy should both be given high priority. In this review we discuss some of the issues relevant to the design of safe molecular MR imaging agents and highlight the excellent safety profile of those agents that have been used clinically to date.
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Affiliation(s)
- David E Sosnovik
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston MA ; Department of Cardiology, Massachusetts General Hospital, Harvard Medical School, Boston MA ; Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston MA
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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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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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Richardson OC, Scott MLJ, Tanner SF, Waterton JC, Buckley DL. Overcoming the low relaxivity of gadofosveset at high field with spin locking. Magn Reson Med 2011; 68:1234-8. [PMID: 22161901 PMCID: PMC3666098 DOI: 10.1002/mrm.23316] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Revised: 11/10/2011] [Accepted: 11/12/2011] [Indexed: 01/13/2023]
Abstract
The contrast agent gadofosveset, which binds reversibly to serum albumin, has a high longitudinal relaxivity at lower magnetic fields (≤3.0 T) but a much lower relaxivity at high fields. Spin locking is sensitive to macromolecular content; it is hypothesized that combining this technique with the albumin-binding properties of gadofosveset may enable increased relaxivity at high fields. In vitro measurements at 4.7 T found significantly higher spin-lock relaxation rates, R1ρ (1/T1ρ), when gadofosveset was serum albumin-bound than when unbound. R1ρ values for a nonbinding contrast agent (gadopentetate dimeglumine) in serum albumin were similar to those for unbound gadofosveset. R2 (1/T2) values were also significantly higher at 4.7 T for serum albumin-bound gadofosveset than for unbound. Spin locking at high field generates significantly higher relaxation rates for gadofosveset than conventional contrast agents and may provide a method for differentiating free and bound molecules at these field strengths.
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Affiliation(s)
- O C Richardson
- Division of Medical Physics, University of Leeds, Leeds, UK
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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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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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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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Ishida M, Ichihara T, Nagata M, Ishida N, Takase S, Kurita T, Ito M, Takeda K, Sakuma H. Quantification of myocardial blood flow using model based analysis of first-pass perfusion MRI: extraction fraction of Gd-DTPA varies with myocardial blood flow in human myocardium. Magn Reson Med 2011; 66:1391-9. [PMID: 21469192 DOI: 10.1002/mrm.22936] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 02/23/2011] [Accepted: 03/05/2011] [Indexed: 01/12/2023]
Abstract
For the absolute quantification of myocardial blood flow (MBF), Patlak plot-derived K1 need to be converted to MBF by using the relation between the extraction fraction of gadolinium contrast agent and MBF. This study was conducted to determine the relation between extraction fraction of Gd-DTPA and MBF in human heart at rest and during stress. Thirty-four patients (19 men, mean age of 66.5 ± 11.0 years) with normal coronary arteries and no myocardial infarction were retrospectively evaluated. First-pass myocardial perfusion MRI during adenosine triphosphate stress and at rest was performed using a dual bolus approach to correct for saturation of the blood signal. Myocardial K1 was quantified by Patlak plot method. Mean MBF was determined from coronary sinus flow measured by phase contrast cine MRI and left ventricle mass measured by cine MRI. The extraction fraction of Gd-DTPA was calculated as the K1 divided by the mean MBF. The extraction fraction of Gd-DTPA was 0.46 ± 0.22 at rest and 0.32 ± 0.13 during stress (P < 0.001). The relationship between extraction fraction (E) and MBF in human myocardium can be approximated as E = 1 - exp(-(0.14 × MBF + 0.56)/MBF). The current results indicate that MBF can be accurately quantified by Patlak plot method of first-pass myocardial perfusion MRI by performing a correction of extraction fraction.
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Affiliation(s)
- Masaki Ishida
- Department of Radiology, Mie University Hospital, Tsu, Mie, Japan
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Gadofosveset-enhanced magnetic resonance imaging of human carotid atherosclerotic plaques: a proof-of-concept study. Invest Radiol 2010; 45:275-81. [PMID: 20351652 DOI: 10.1097/rli.0b013e3181d5466b] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To investigate the potential of gadofosveset-enhanced MR imaging for the characterization of human carotid atherosclerotic plaques. MATERIALS AND METHODS Sixteen (9 symptomatic, 7 asymptomatic) patients with 70% to 99% carotid stenosis (according to NASCET criteria) were included (13 men, 3 women, mean age 67.6 years). All patients underwent baseline precontrast MR imaging of the carotid plaque. Immediately after completion of the baseline examination, 0.03 mmol/kg gadofosveset was administered. At 24 hours postinjection, the acquisition was repeated. Twelve patients were scheduled for carotid endarterectomy. Carotid endarterectomy specimens were HE-, CD31-, CD68-, and albumin-stained to correlate signal enhancement with plaque composition, intraplaque microvessel density, and macrophage and albumin content. A random intercept model was used to compare signal enhancement between symptomatic and asymptomatic patients, adjusting for size of various plaque components. This study was approved by the institutional medical ethics committee. All participants gave written informed consent. RESULTS Signal enhancement (SE) of the plaque was significantly higher in symptomatic patients compared with asymptomatic patients (median log SE 0.182 vs. -0.109, respectively, P < 0.001). A positive association (as expressed by a regression coefficient beta = 0.0035) was found between signal enhancement on the log scale and intraplaque albumin content (P = 0.038). There was no association between signal enhancement and various other plaque components. CONCLUSION In this study, the potential of gadofosveset-enhanced human carotid plaque MR imaging for identification of high-risk plaques was demonstrated. Signal enhancement of the plaque after administration of gadofosveset was associated with differences in intraplaque albumin content. Although promising, we emphasize that these results are based on a small patient population. Larger prospective studies are warranted.
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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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Wang Y, Spiller M, Caravan P. Evidence for weak protein binding of commercial extracellular gadolinium contrast agents. Magn Reson Med 2010; 63:609-16. [DOI: 10.1002/mrm.22214] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Maki JH, Wang M, Wilson GJ, Shutske MG, Leiner T. Highly accelerated first-pass contrast-enhanced magnetic resonance angiography of the peripheral vasculature: Comparison of gadofosveset trisodium with gadopentetate dimeglumine contrast agents. J Magn Reson Imaging 2009; 30:1085-92. [DOI: 10.1002/jmri.21961] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Essig M, Rohrer M, Giesel F, Tüttenberg J, Weber MA, Michaely H, Gerigk L, Voth M. Human brain tumor imaging with a protein-binding MR contrast agent: initial experience. Eur Radiol 2009; 20:218-26. [DOI: 10.1007/s00330-009-1530-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Revised: 06/09/2009] [Accepted: 06/22/2009] [Indexed: 10/20/2022]
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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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Alford JK, Rutt BK, Scholl TJ, Handler WB, Chronik BA. Delta relaxation enhanced MR: Improving activation-specificity of molecular probes throughR1dispersion imaging. Magn Reson Med 2009; 61:796-802. [DOI: 10.1002/mrm.21933] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Thoracic and abdominal MRA with gadofosveset: influence of injection rate on vessel signal and image quality. Eur Radiol 2009; 19:1932-8. [PMID: 19283385 DOI: 10.1007/s00330-009-1381-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Revised: 01/27/2009] [Accepted: 02/14/2009] [Indexed: 01/20/2023]
Abstract
The purpose of this study was to investigate the influence of different injection rates on the maximum signal intensity and the arterio-venous transit time of dynamic gadofosveset-enhanced first pass MR angiography (MRA). Twenty-one healthy male volunteers were examined with a time-resolved echo-shared MRA at 1.5 T. The volunteers were assigned into three groups using injection rates of either 1, 2 or 4 ml/s. The maximal signal enhancement and peak signal-to-noise ratio in the pulmonary trunk, the aortic arch, the abdominal aorta as well as both kidneys and lung parenchyma were analyzed. The arterio-venous transit time was determined. The time between maximal enhancement of the pulmonary trunk and the aortic arch was higher with the slow injection rate of 1 ml/s, while there were no differences in the time between maximal enhancement of the aortic arch and the abdominal aorta above or below the origin of the renal veins with all three injection rates. With the slow injection protocol of 1 ml/s a longer purely arterial phase of 10.5 s was achieved compared to 7.7 s with higher injection rates (p = 0.045). The time between maximal aortic signal intensity and maximal renal enhancement was equal for all injection protocols.
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Nair SA, Kolodziej AF, Bhole G, Greenfield MT, McMurry TJ, Caravan P. Monovalent and bivalent fibrin-specific MRI contrast agents for detection of thrombus. Angew Chem Int Ed Engl 2008; 47:4918-21. [PMID: 18496805 DOI: 10.1002/anie.200800563] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Nair S, Kolodziej A, Bhole G, Greenfield M, McMurry T, Caravan P. Monovalent and Bivalent Fibrin-specific MRI Contrast Agents for Detection of Thrombus. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200800563] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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