51
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Lock LL, Li Y, Mao X, Chen H, Staedtke V, Bai R, Ma W, Lin R, Li Y, Liu G, Cui H. One-Component Supramolecular Filament Hydrogels as Theranostic Label-Free Magnetic Resonance Imaging Agents. ACS NANO 2017; 11:797-805. [PMID: 28075559 PMCID: PMC5773287 DOI: 10.1021/acsnano.6b07196] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Gadolinium (Gd)-based compounds and materials are the most commonly used magnetic resonance imaging (MRI) contrast agents in the clinic; however, safety concerns associated with their toxicities in the free ionic form have promoted the development of new generations of metal-free contrast agents. Here we report a supramolecular strategy to convert an FDA-approved anticancer drug, Pemetrexed (Pem), to a molecular hydrogelator with inherent chemical exchange saturation transfer (CEST) MRI signals. The rationally designed drug-peptide conjugate can spontaneously associate into filamentous assemblies under physiological conditions and consequently form theranostic supramolecular hydrogels for injectable delivery. We demonstrated that the local delivery and distribution of Pem-peptide nanofiber hydrogels can be directly assessed using CEST MRI in a mouse glioma model. Our work lays out the foundation for the development of drug-constructed theranostic supramolecular materials with an inherent CEST MRI signal that enables noninvasive monitoring of their in vivo distribution and drug release.
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Affiliation(s)
- Lye Lin Lock
- Department of Oncology, The First Affiliated Hospital of Zhengzhou University, 1 Jianshe Eastern Road, Zhengzhou 450052, Henan, China
- Department of Chemical and Biomolecular Engineering and Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Yuguo Li
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, United States
| | - Xinpei Mao
- Department of Chemical and Biomolecular Engineering and Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Hanwei Chen
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, United States
- Department of Radiology, Panyu Central Hospital, Guangzhou, China
| | - Verena Staedtke
- Department of Neurosurgery, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, United States
| | - Renyuan Bai
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, United States
| | - Wang Ma
- Department of Oncology, The First Affiliated Hospital of Zhengzhou University, 1 Jianshe Eastern Road, Zhengzhou 450052, Henan, China
| | - Ran Lin
- Department of Chemical and Biomolecular Engineering and Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Yi Li
- Department of Chemical and Biomolecular Engineering and Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Guanshu Liu
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21205, United States
| | - Honggang Cui
- Department of Oncology, The First Affiliated Hospital of Zhengzhou University, 1 Jianshe Eastern Road, Zhengzhou 450052, Henan, China
- Department of Chemical and Biomolecular Engineering and Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, Maryland 21218, United States
- Department of Oncology and Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, United States
- Center for Nanomedicine, The Wilmer Eye Institute, Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, Maryland 21231, United States
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52
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Zhang L, Martins AF, Mai Y, Zhao P, Funk AM, Clavijo Jordan MV, Zhang S, Chen W, Wu Y, Sherry AD. Imaging Extracellular Lactate In Vitro and In Vivo Using CEST MRI and a Paramagnetic Shift Reagent. Chemistry 2017; 23:1752-1756. [PMID: 27987233 DOI: 10.1002/chem.201604558] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 12/07/2016] [Indexed: 12/22/2022]
Abstract
Overproduction of lactate is a hallmark of cancer, yet a method to quantitatively measure lactate production by cancer cells is not straight-forward. Chemical exchange saturation transfer magnetic resonance imaging (CEST MRI) can potentially be used to image lactate but the small difference in chemical shift of the lactate -OH proton and water proton resonances make it challenging. Like other spectroscopic methods, CEST MRI cannot discriminate intracellular lactate from extracellular lactate. Herein, we demonstrate a relatively simple way to shift the lactate -OH proton resonance far away from water by addition of the paramagnetic shift reagent, EuDO3A, while retaining the CEST properties of lactate itself. The potential of the method was demonstrated by imaging extracellular lactate excreted from lung cancer cells in tissue culture without interference from other components in the culture media and by imaging excess lactate excreted into the bladder of a mouse.
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Affiliation(s)
- Lei Zhang
- Department of Chemistry and Biochemistry, University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080, USA
| | - André F Martins
- Department of Chemistry and Biochemistry, University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080, USA
| | - Yuyan Mai
- Department of Chemistry and Biochemistry, University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080, USA
| | - Piyu Zhao
- Department of Chemistry and Biochemistry, University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080, USA
| | - Alexander M Funk
- Advanced Imaging Research Center, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - M Veronica Clavijo Jordan
- Advanced Imaging Research Center, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Shanrong Zhang
- Advanced Imaging Research Center, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Wei Chen
- Advanced Imaging Research Center, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Yunkou Wu
- Advanced Imaging Research Center, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - A Dean Sherry
- Department of Chemistry and Biochemistry, University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080, USA.,Advanced Imaging Research Center, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
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53
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In Vitro and In Vivo Assessment of Nonionic Iodinated Radiographic Molecules as Chemical Exchange Saturation Transfer Magnetic Resonance Imaging Tumor Perfusion Agents. Invest Radiol 2016; 51:155-62. [PMID: 26460826 DOI: 10.1097/rli.0000000000000217] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES The aim of this study was to evaluate 4 nonionic x-ray iodinated contrast agents (CAs), commonly used in radiographic procedures, as novel chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) agents by assessing their in vitro exchange properties and preliminary in vivo use as tumor enhancing agents. MATERIALS AND METHODS The CEST properties, as function of pH (range, 5.5-7.9) and of radio frequency conditions (irradiation field strength range of 1-9 μT and time of 1-9 seconds), have been determined at 7 T and 310 K for 4 x-ray CAs commonly used in clinical settings, namely, iomeprol, iohexol, ioversol, and iodixanol. Their in vivo properties have been investigated upon intravenous injection in a murine HER2+ breast tumor model (n = 4 mice for each CA) using both computed tomography (CT) and MRI modalities. RESULTS The prototropic exchange rates measured for the 4 investigated iodinated molecules showed strong pH dependence with base catalyzed exchange rate that was faster for monomeric compounds (20-4000 Hz in the pH range of 5.5-7.9). Computed tomography quantification showed marked (up to 2 mg I/mL concentration) and prolonged accumulation (up to 30 minutes postinjection) inside tumor regions. Among the 4 agents we tested, iohexol and ioversol display good CEST contrast properties at 7 T, and in vivo results confirmed strong and prolonged contrast enhancement of the tumors, with elevated extravasation fractions (74%-91%). A strong and significant correlation was found between CT and CEST-MRI tumor-enhanced images (R = 0.70, P < 0.01). CONCLUSIONS The obtained results demonstrate that iohexol and ioversol, 2 commonly used radiographic compounds, can be used as MRI perfusion agents, particularly useful when serial images acquisitions are needed to complement CT information.
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54
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Diamagnetic Imaging Agents with a Modular Chemical Design for Quantitative Detection of β-Galactosidase and β-Glucuronidase Activities with CatalyCEST MRI. Bioconjug Chem 2016; 27:2549-2557. [PMID: 27657647 PMCID: PMC6013409 DOI: 10.1021/acs.bioconjchem.6b00482] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Imaging agents for the noninvasive in vivo detection of enzyme activity in preclinical and clinical settings could have fundamental implications in the field of drug discovery. Furthermore, a new class of targeted prodrug treatments takes advantage of high enzyme activity to tailor therapy and improve treatment outcomes. Herein, we report the design and synthesis of new magnetic resonance imaging (MRI) agents that quantitatively detect β-galactosidase and β-glucuronidase activities by measuring changes in chemical exchange saturation transfer (CEST). Based on a modular approach, we incorporated the enzymes' respective substrates to a salicylate moiety with a chromogenic spacer via a carbamate linkage. This furnished highly selective diamagnetic CEST agents that detected and quantified enzyme activities of glycoside hydrolase enzymes. Michaelis-Menten enzyme kinetics studies were performed by monitoring catalyCEST MRI signals, which were validated with UV-vis assays.
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55
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Ngen EJ, Bar-Shir A, Jablonska A, Liu G, Song X, Ansari R, Bulte JWM, Janowski M, Pearl M, Walczak P, Gilad AA. Imaging the DNA Alkylator Melphalan by CEST MRI: An Advanced Approach to Theranostics. Mol Pharm 2016; 13:3043-53. [PMID: 27398883 DOI: 10.1021/acs.molpharmaceut.6b00130] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Brain tumors are among the most lethal types of tumors. Therapeutic response variability and failure in patients have been attributed to several factors, including inadequate drug delivery to tumors due to the blood-brain barrier (BBB). Consequently, drug delivery strategies are being developed for the local and targeted delivery of drugs to brain tumors. These drug delivery strategies could benefit from new approaches to monitor the delivery of drugs to tumors. Here, we evaluated the feasibility of imaging 4-[bis(2-chloroethyl)amino]-l-phenylalanine (melphalan), a clinically used DNA alkylating agent, using chemical exchange saturation transfer magnetic resonance imaging (CEST MRI), for theranostic applications. We evaluated the physicochemical parameters that affect melphalan's CEST contrast and demonstrated the feasibility of imaging the unmodified drug by saturating its exchangeable amine protons. Melphalan generated a CEST signal despite its reactivity in an aqueous milieu. The maximum CEST signal was observed at pH 6.2. This CEST contrast trend was then used to monitor therapeutic responses to melphalan in vitro. Upon cell death, the decrease in cellular pH from ∼7.4 to ∼6.4 caused an amplification of the melphalan CEST signal. This is contrary to what has been reported for other CEST contrast agents used for imaging cell death, where a decrease in the cellular pH following cell death results in a decrease in the CEST signal. Ultimately, this method could be used to noninvasively monitor melphalan delivery to brain tumors and also to validate therapeutic responses to melphalan clinically.
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Affiliation(s)
- Ethel J Ngen
- Division of Magnetic Resonance Research, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine , Baltimore, Maryland 21205, United States.,Cellular Imaging Section and Vascular Biology Program, Institute for Cellular Engineering, The Johns Hopkins University School of Medicine , Baltimore, Maryland 21205, United States
| | - Amnon Bar-Shir
- Division of Magnetic Resonance Research, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine , Baltimore, Maryland 21205, United States.,Cellular Imaging Section and Vascular Biology Program, Institute for Cellular Engineering, The Johns Hopkins University School of Medicine , Baltimore, Maryland 21205, United States
| | - Anna Jablonska
- Division of Magnetic Resonance Research, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine , Baltimore, Maryland 21205, United States.,Cellular Imaging Section and Vascular Biology Program, Institute for Cellular Engineering, The Johns Hopkins University School of Medicine , Baltimore, Maryland 21205, United States
| | - Guanshu Liu
- Division of Magnetic Resonance Research, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine , Baltimore, Maryland 21205, United States.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute , Baltimore, Maryland 21205, United States
| | - Xiaolei Song
- Division of Magnetic Resonance Research, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine , Baltimore, Maryland 21205, United States.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute , Baltimore, Maryland 21205, United States
| | | | - Jeff W M Bulte
- Division of Magnetic Resonance Research, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine , Baltimore, Maryland 21205, United States.,Cellular Imaging Section and Vascular Biology Program, Institute for Cellular Engineering, The Johns Hopkins University School of Medicine , Baltimore, Maryland 21205, United States.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute , Baltimore, Maryland 21205, United States
| | - Miroslaw Janowski
- Division of Magnetic Resonance Research, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine , Baltimore, Maryland 21205, United States.,Cellular Imaging Section and Vascular Biology Program, Institute for Cellular Engineering, The Johns Hopkins University School of Medicine , Baltimore, Maryland 21205, United States.,NeuroRepair Department, Mossakowski Medical Research Centre, PAS , 02106 Warsaw, Poland.,Department of Neurosurgery, Mossakowski Medical Research Centre, PAS , 02106 Warsaw, Poland
| | - Monica Pearl
- Division of Interventional Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Sciences, The Johns Hopkins University School of Medicine , Baltimore, Maryland 21205, United States.,Department of Radiology, Children's National Medical Center , Washington, D.C. 20010, United States
| | - Piotr Walczak
- Division of Magnetic Resonance Research, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine , Baltimore, Maryland 21205, United States.,Cellular Imaging Section and Vascular Biology Program, Institute for Cellular Engineering, The Johns Hopkins University School of Medicine , Baltimore, Maryland 21205, United States.,Department of Radiology, Faculty of Medical Sciences, University of Warmia and Mazury , Olsztyn, Poland
| | - Assaf A Gilad
- Division of Magnetic Resonance Research, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine , Baltimore, Maryland 21205, United States.,Cellular Imaging Section and Vascular Biology Program, Institute for Cellular Engineering, The Johns Hopkins University School of Medicine , Baltimore, Maryland 21205, United States.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute , Baltimore, Maryland 21205, United States
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56
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Daryaei I, Mohammadebrahim Ghaffari M, Jones KM, Pagel MD. Detection of Alkaline Phosphatase Enzyme Activity with a CatalyCEST MRI Biosensor. ACS Sens 2016; 1:857-861. [PMID: 30246144 DOI: 10.1021/acssensors.6b00203] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Responsive CEST MRI biosensors offer good sensitivity and excellent specificity for detection of biomarkers with great potential for clinical translation. We report the application of fosfosal, a phosphorylated form of salicylic acid, for the detection of alkaline phosphatase (AP) enzyme. We detected conversion of fosfosal to salicylic acid in the presence of the enzyme by CEST MRI. Importantly the technique was able to detect AP enzyme expressed in cells in the presence of other cell components, which improves specificity. Various isoforms of the enzyme showed different Michaelis-Menten kinetics and yet these kinetics studies indicated very efficient catalytic rates. Our results with the fosfosal biosensor encourage further in vivo studies.
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Affiliation(s)
- Iman Daryaei
- Biological
Chemistry Program, Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85719, United States
| | - Mahsa Mohammadebrahim Ghaffari
- Biological
Chemistry Program, Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85719, United States
| | - Kyle M. Jones
- Department
of Biomedical Engineering, University of Arizona, Tucson, Arizona 85721, United States
| | - Mark D. Pagel
- University of Arizona Cancer Center, Tucson, Arizona 85724, United States
- Department
of Medical Imaging, University of Arizona, Tucson, Arizona 85724, United States
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57
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Yang X, Song X, Banerjee SR, Li Y, Byun Y, Liu G, Bhujwalla ZM, Pomper MG, McMahon MT. Developing imidazoles as CEST MRI pH sensors. CONTRAST MEDIA & MOLECULAR IMAGING 2016; 11:304-12. [PMID: 27071959 PMCID: PMC5201433 DOI: 10.1002/cmmi.1693] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 02/17/2016] [Accepted: 02/22/2016] [Indexed: 12/21/2022]
Abstract
A series of intra-molecular hydrogen bonded imidazoles and related heterocyclic compounds were screened for their N-H chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) contrast properties. Of the compounds, imidazole-4,5-dicarboxamides (I45DCs) were found to provide the strongest contrast, with the contrast produced at a large chemical shift from water (7.8 ppm) and strongly dependent on pH. We have tested several probes based on this scaffold, and demonstrated that these probes could be applied for in vivo detection of kidney pH after intravenous administration. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Xing Yang
- Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Xiaolei Song
- Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Sangeeta Ray Banerjee
- Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yuguo Li
- Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Youngjoo Byun
- College of Pharmacy, Korea University, Sejong, South Korea
| | - Guanshu Liu
- Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Zaver M. Bhujwalla
- Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Martin G. Pomper
- Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Michael T. McMahon
- Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
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58
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Song X, Walczak P, He X, Yang X, Pearl M, Bulte JWM, Pomper MG, McMahon MT, Janowski M. Salicylic acid analogues as chemical exchange saturation transfer MRI contrast agents for the assessment of brain perfusion territory and blood-brain barrier opening after intra-arterial infusion. J Cereb Blood Flow Metab 2016; 36:1186-94. [PMID: 26980755 PMCID: PMC4929703 DOI: 10.1177/0271678x16637882] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Accepted: 02/01/2016] [Indexed: 11/17/2022]
Abstract
The blood-brain barrier (BBB) is a major obstacle for drug delivery to the brain. Predicted, focal opening of the BBB through intra-arterial infusion of hyperosmolar mannitol is feasible, but there is a need to facilitate imaging techniques (e.g. MRI) to guide interventional procedures and assess the outcomes. Here, we show that salicylic acid analogues (SAA) can depict the brain territory supplied by the catheter and detect the BBB opening, through chemical exchange saturation transfer (CEST) MRI. Hyperosmolar SAA solutions themselves are also capable of opening the BBB, and, when multiple SAA agents were co-injected, their locoregional perfusion could be differentiated.
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Affiliation(s)
- Xiaolei Song
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltmore, MD, USA F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Piotr Walczak
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltmore, MD, USA F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA Department of Radiology, Faculty of Medical Sciences, University of Warmia and Mazury, Olsztyn, Poland
| | - Xiaowei He
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltmore, MD, USA School of Information Sciences and Technology, Northwest University, Xi'an, P. R. China
| | - Xing Yang
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltmore, MD, USA
| | - Monica Pearl
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltmore, MD, USA
| | - Jeff W M Bulte
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltmore, MD, USA F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Martin G Pomper
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltmore, MD, USA
| | - Michael T McMahon
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltmore, MD, USA F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Mirosław Janowski
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltmore, MD, USA Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA NeuroRepair Department, MMRC, PAS, Warsaw, Poland Department of Neurosurgery, MMRC, PAS, Warsaw, Poland
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59
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Liu H, Jablonska A, Li Y, Cao S, Liu D, Chen H, Van Zijl PCM, Bulte JW, Janowski M, Walczak P, Liu G. Label-free CEST MRI Detection of Citicoline-Liposome Drug Delivery in Ischemic Stroke. Am J Cancer Res 2016; 6:1588-600. [PMID: 27446492 PMCID: PMC4955057 DOI: 10.7150/thno.15492] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 05/01/2016] [Indexed: 12/21/2022] Open
Abstract
Citicoline (CDPC) is a natural supplement with well-documented neuroprotective effects in the treatment of neurodegenerative diseases. In the present study, we sought to exploit citicoline as a theranostic agent with its inherent chemical exchange saturation transfer (CEST) MRI signal, which can be directly used as an MRI guidance in the citicoline drug delivery. Our in vitro CEST MRI results showed citicoline has two inherent CEST signals at +1 and +2 ppm, attributed to exchangeable hydroxyl and amine protons, respectively. To facilitate the targeted drug delivery of citicoline to ischemic regions, we prepared liposomes encapsulating citicoline (CDPC-lipo) and characterized the particle properties and CEST MRI properties. The in vivo CEST MRI detection of liposomal citicoline was then examined in a rat brain model of unilateral transient ischemia induced by a two-hour middle cerebral artery occlusion. The results showed that the delivery of CPDC-lipo to the brain ischemic areas could be monitored and quantified by CEST MRI. When administered intra-arterially, CDPC-lipo clearly demonstrated a detectable CEST MRI contrast at 2 ppm. CEST MRI revealed that liposomes preferentially accumulated in the areas of ischemia with a disrupted blood-brain-barrier. We furthermore used CEST MRI to detect the improvement in drug delivery using CDPC-lipo targeted against vascular cell adhesion molecule (VCAM)-1 in the same animal model. The MRI findings were validated using fluorescence microscopy. Hence, liposomal citicoline represents a prototype theranostic system, where the therapeutic agent can be detected directly by CEST MRI in a label-free fashion.
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60
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Sinharay S, Randtke EA, Jones KM, Howison CM, Chambers SK, Kobayashi H, Pagel MD. Noninvasive detection of enzyme activity in tumor models of human ovarian cancer using catalyCEST MRI. Magn Reson Med 2016; 77:2005-2014. [PMID: 27221386 DOI: 10.1002/mrm.26278] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 04/25/2016] [Accepted: 04/25/2016] [Indexed: 12/17/2022]
Abstract
PURPOSE We proposed to detect the in vivo enzyme activity of γ-glutamyl transferase (GGT) within mouse models of human ovarian cancers using catalyCEST MRI with a diamagnetic CEST agent. METHODS A CEST-FISP MRI protocol and a diamagnetic CEST agent were developed to detect GGT enzyme activity in biochemical solution. A quantitative Michaelis-Menten enzyme kinetics study was performed to confirm that catalyCEST MRI can measure enzyme activity. In vivo catalyCEST MRI studies generated pixel-wise activity maps of GGT activities. Ex vivo fluorescence imaging was performed for validation. RESULTS CatalyCEST MRI selectively detected two CEST signals from a single CEST agent, whereby one CEST signal was responsive to GGT enzyme activity and the other CEST signal was an unresponsive control signal. The comparison of these CEST signals facilitated in vivo catalyCEST MRI studies that detected high GGT activity in OVCAR-8 tumors, low GGT activity in OVCAR-3 tumors, and low or no GGT activity in muscle tissues. CONCLUSION CatalyCEST MRI with a diamagnetic CEST agent can detect the level of GGT enzyme activity within in vivo tumor models of human ovarian cancers. Magn Reson Med 77:2005-2014, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Sanhita Sinharay
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Edward A Randtke
- Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA
| | - Kyle M Jones
- Biomedical Engineering Graduate Interdisciplinary Program, University of Arizona, Tucson, Arizona, USA
| | | | - Setsuko K Chambers
- Department of Obstetrics and Gynecology, University of Arizona, Tucson, Arizona, USA.,University of Arizona Cancer Center, University of Arizona, Tucson, Arizona, USA
| | - Hisataka Kobayashi
- Laboratory of Molecular Theranostics, National Cancer Institute, NIH, Bethesda, Maryland, USA
| | - Mark D Pagel
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA.,Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA.,University of Arizona Cancer Center, University of Arizona, Tucson, Arizona, USA
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61
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Lesniak WG, Oskolkov N, Song X, Lal B, Yang X, Pomper M, Laterra J, Nimmagadda S, McMahon MT. Salicylic Acid Conjugated Dendrimers Are a Tunable, High Performance CEST MRI NanoPlatform. NANO LETTERS 2016; 16:2248-53. [PMID: 26910126 PMCID: PMC4890470 DOI: 10.1021/acs.nanolett.5b04517] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Chemical exchange saturation transfer (CEST) is a novel MRI contrast mechanism that is well suited for imaging, however, existing small molecule CEST agents suffer from low sensitivity. We have developed salicylic acid conjugated dendrimers as a versatile, high performance nanoplatform. In particular, we have prepared nanocarriers based on generation 5-poly(amidoamine) (PAMAM) dendrimers with salicylic acid covalently attached to their surface. The resulting conjugates produce strong CEST contrast 9.4 ppm from water with the proton exchange tunable from ∼1000 s(-1) to ∼4500 s(-1) making these dendrimers well suited for sensitive detection. Furthermore, we demonstrate that these conjugates can be used for monitoring convection enhanced delivery into U87 glioblastoma bearing mice, with the contrast produced by these nanoparticles persisting for over 1.5 h and distributed over ∼50% of the tumors. Our results demonstrate that SA modified dendrimers present a promising new nanoplatform for medical applications.
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Affiliation(s)
- Wojciech G. Lesniak
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, United States
| | - Nikita Oskolkov
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, United States
| | - Xiaolei Song
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, United States
| | - Bachchu Lal
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, United States
| | - Xing Yang
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, United States
| | - Martin Pomper
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, United States
| | - John Laterra
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, United States
| | - Sridhar Nimmagadda
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, United States
| | - Michael T. McMahon
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21287, United States
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Fernández-Cuervo G, Sinharay S, Pagel MD. A CatalyCEST MRI Contrast Agent that Can Simultaneously Detect Two Enzyme Activities. Chembiochem 2016; 17:383-7. [PMID: 26693680 PMCID: PMC4814164 DOI: 10.1002/cbic.201500586] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Indexed: 12/28/2022]
Abstract
The simultaneous detection of multiple enzyme activities can improve the specificity of disease diagnoses. We therefore synthesized and characterized a diamagnetic chemical exchange saturation transfer (CEST) MRI contrast agent that can simultaneously detect two enzyme activities. Sulfatase and esterase enzymes cleave the ligands of the CEST agent, releasing salicylic acid that can be detected with CEST MRI. Importantly, both enzymes are required to activate the agent to produce a CEST MRI contrast, and the CEST agent was stable without enzyme treatment. These results established that this diamagnetic CEST MRI contrast agent is a platform technology with a modular design that can be potentially exploited to detect other combinations of enzyme activities, which can expand the armamentarium of contrast agents for molecular imaging.
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Affiliation(s)
- Gabriela Fernández-Cuervo
- Department of Pharmaceutical Sciences, University of Arizona, 1515 N. Campbell Ave., Tucson, AZ, 85724, USA
| | - Sanhita Sinharay
- Department of Chemistry and Biochemistry, University of Arizona, 1515 N. Campbell Ave., Tucson, AZ, 85724, USA
| | - Mark D Pagel
- Department of Medical Imaging, University of Arizona, 1515 N. Campbell Ave., Tucson, AZ, 85724, USA.
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63
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Hingorani DV, Montano LA, Randtke EA, Lee YS, Cárdenas-Rodríguez J, Pagel MD. A single diamagnetic catalyCEST MRI contrast agent that detects cathepsin B enzyme activity by using a ratio of two CEST signals. CONTRAST MEDIA & MOLECULAR IMAGING 2016; 11:130-8. [PMID: 26633584 PMCID: PMC4882611 DOI: 10.1002/cmmi.1672] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 09/06/2015] [Accepted: 10/02/2015] [Indexed: 12/31/2022]
Abstract
CatalyCEST MRI can detect enzyme activity by monitoring the change in chemical exchange with water after a contrast agent is cleaved by an enzyme. Often these molecules use paramagnetic metals and are delivered with an additional non-responsive reference molecule. To improve this approach for molecular imaging, a single diamagnetic agent with enzyme-responsive and enzyme-unresponsive CEST signals was synthesized and characterized. The CEST signal from the aryl amide disappeared after cleavage of a dipeptidyl ligand with cathepsin B, while a salicylic acid moiety was largely unresponsive to enzyme activity. The ratiometric comparison of the two CEST signals from the same agent allowed for concentration independent measurements of enzyme activity. The chemical exchange rate of the salicylic acid moiety was unchanged after enzyme catalysis, which further validated that this moiety was enzyme-unresponsive. The temperature dependence of the chemical exchange rate of the salicylic acid moiety was non-Arrhenius, suggesting a two-step chemical exchange mechanism for salicylic acid. The good detection sensitivity at low saturation power facilitates clinical translation, along with the potentially low toxicity of a non-metallic MRI contrast agent. The modular design of the agent constitutes a platform technology that expands the variety of agents that may be employed by catalyCEST MRI for molecular imaging.
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Affiliation(s)
- Dina V. Hingorani
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
- Department of Surgery, University of California, San Diego, 9500 Gilman Dr, George Palade 310, La Jolla, CA 92093-0647, USA
| | - Luis A. Montano
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
| | - Edward A. Randtke
- Department of Medical Imaging, University of Arizona, Tucson, AZ, USA
| | - Yeon Sun Lee
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
| | | | - Mark D. Pagel
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
- Department of Medical Imaging, University of Arizona, Tucson, AZ, USA
- University of Arizona Cancer Center, 1515 N Campbell Ave., Tucson, AZ, 85724-5024, USA
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64
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Yoshimaru ES, Randtke EA, Pagel MD, Cárdenas-Rodríguez J. Design and optimization of pulsed Chemical Exchange Saturation Transfer MRI using a multiobjective genetic algorithm. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 263:184-192. [PMID: 26778301 PMCID: PMC4871615 DOI: 10.1016/j.jmr.2015.11.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 11/10/2015] [Accepted: 11/13/2015] [Indexed: 05/08/2023]
Abstract
Pulsed Chemical Exchange Saturation Transfer (CEST) MRI experimental parameters and RF saturation pulse shapes were optimized using a multiobjective genetic algorithm. The optimization was carried out for RF saturation duty cycles of 50% and 90%, and results were compared to continuous wave saturation and Gaussian waveform. In both simulation and phantom experiments, continuous wave saturation performed the best, followed by parameters and shapes optimized by the genetic algorithm and then followed by Gaussian waveform. We have successfully demonstrated that the genetic algorithm is able to optimize pulse CEST parameters and that the results are translatable to clinical scanners.
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Affiliation(s)
- Eriko S Yoshimaru
- Department of Medical Imaging, University of Arizona, Tucson, AZ, USA
| | - Edward A Randtke
- Department of Medical Imaging, University of Arizona, Tucson, AZ, USA
| | - Mark D Pagel
- Department of Medical Imaging, University of Arizona, Tucson, AZ, USA
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65
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Zhu L, Yang Y, Farquhar K, Wang J, Tian C, Ranville J, Boyes SG. Surface Modification of Gd Nanoparticles with pH-Responsive Block Copolymers for Use As Smart MRI Contrast Agents. ACS APPLIED MATERIALS & INTERFACES 2016; 8:5040-5050. [PMID: 26790986 DOI: 10.1021/acsami.5b12463] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Despite recent advances in the understanding of fundamental cancer biology, cancer remains the second most common cause of death in the United States. One of the primary factors indicative of high cancer morbidity and mortality and aggressive cancer phenotypes is tumors with a low extracellular pH (pHe). Thus, the ability to measure tumor pHe in vivo using noninvasive and accurate techniques that also provide high spatiotemporal resolution has become increasingly important and is of great interest to researchers and clinicians. In an effort to develop a pH-responsive magnetic resonance imaging (MRI) contrast agent (CA) that has the potential to be used to measure tumor pHe, well-defined pH-responsive polymers, synthesized via reversible addition-fragmentation chain transfer polymerization, were attached to the surface of gadolinium-based nanoparticles (GdNPs) via a "grafting to" method after reduction of the thiocarbonylthio end groups. The successful modification of the GdNPs was verified by transmission electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and dynamic light scattering. The performance of the pH-responsive polymer modified GdNPs was then evaluated for potential use as smart MRI CAs via monitoring the relaxivity changes with changing environmental pH. The results suggested that the pH-responsive polymers can be used to effectively modify the GdNPs surface to prepare a smart contrast agent for MRI.
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Affiliation(s)
- Liping Zhu
- Department of Chemistry and Geochemistry, Colorado School of Mines , Golden, Colorado 80401, United States
| | - Yuan Yang
- Department of Chemistry and Geochemistry, Colorado School of Mines , Golden, Colorado 80401, United States
| | - Kirsten Farquhar
- Department of Chemistry and Geochemistry, Colorado School of Mines , Golden, Colorado 80401, United States
| | - Jingjing Wang
- Department of Chemistry and Geochemistry, Colorado School of Mines , Golden, Colorado 80401, United States
| | - Chixia Tian
- Department of Chemistry and Geochemistry, Colorado School of Mines , Golden, Colorado 80401, United States
| | - James Ranville
- Department of Chemistry and Geochemistry, Colorado School of Mines , Golden, Colorado 80401, United States
| | - Stephen G Boyes
- Department of Chemistry and Geochemistry, Colorado School of Mines , Golden, Colorado 80401, United States
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66
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Li J, Feng X, Zhu W, Oskolkov N, Zhou T, Kim BK, Baig N, McMahon MT, Oldfield E. Chemical Exchange Saturation Transfer (CEST) Agents: Quantum Chemistry and MRI. Chemistry 2016; 22:264-71. [PMID: 26616530 PMCID: PMC4715718 DOI: 10.1002/chem.201503942] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Indexed: 01/31/2023]
Abstract
Diamagnetic chemical exchange saturation transfer (CEST) contrast agents offer an alternative to Gd(3+) -based contrast agents for MRI. They are characterized by containing protons that can rapidly exchange with water and it is advantageous to have these protons resonate in a spectral window that is far removed from water. Herein, we report the first results of DFT calculations of the (1) H nuclear magnetic shieldings in 41 CEST agents, finding that the experimental shifts can be well predicted (R(2) =0.882). We tested a subset of compounds with the best MRI properties for toxicity and for activity as uncouplers, then obtained mice kidney CEST MRI images for three of the most promising leads finding 16 (2,4-dihydroxybenzoic acid) to be one of the most promising CEST MRI contrast agents to date. Overall, the results are of interest since they show that (1) H NMR shifts for CEST agents-charged species-can be well predicted, and that several leads have low toxicity and yield good in vivo MR images.
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Affiliation(s)
- Jikun Li
- Department of Chemistry University of Illinois at Urbana Champaign, 600 South Mathews Urbana, IL 61801 (USA)
| | - Xinxin Feng
- Department of Chemistry University of Illinois at Urbana Champaign, 600 South Mathews Urbana, IL 61801 (USA)
| | - Wei Zhu
- Department of Chemistry University of Illinois at Urbana Champaign, 600 South Mathews Urbana, IL 61801 (USA)
| | - Nikita Oskolkov
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, Maryland 21287 (USA)
| | - Tianhui Zhou
- Department of Chemistry University of Illinois at Urbana Champaign, 600 South Mathews Urbana, IL 61801 (USA)
| | - Boo Kyung Kim
- Department of Chemistry University of Illinois at Urbana Champaign, 600 South Mathews Urbana, IL 61801 (USA)
| | - Noman Baig
- Department of Chemistry University of Illinois at Urbana Champaign, 600 South Mathews Urbana, IL 61801 (USA)
| | - Michael T McMahon
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, Maryland 21287 (USA).
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 N. Broadway, Baltimore, MD 21287 (USA).
| | - Eric Oldfield
- Department of Chemistry University of Illinois at Urbana Champaign, 600 South Mathews Urbana, IL 61801 (USA).
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67
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Kuda-Wedagedara ANW, Allen MJ. Enhancing magnetic resonance imaging with contrast agents for ultra-high field strengths. Analyst 2015; 139:4401-10. [PMID: 25054827 DOI: 10.1039/c4an00990h] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Contrast agents are diagnostic tools that often complement magnetic resonance imaging. At ultra-high field strengths (≥7 T), magnetic resonance imaging is capable of generating desirable high signal-to-noise ratios, but clinically available contrast agents are less effective at ultra-high field strengths relative to lower fields. This gap in effectiveness demands the development of contrast agents for ultra-high field strengths. In this minireview, we summarize contrast agents reported during the last three years that focused on ultra-high field strengths.
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68
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Wu Y, Zhang S, Soesbe TC, Yu J, Vinogradov E, Lenkinski RE, Sherry AD. pH imaging of mouse kidneys in vivo using a frequency-dependent paraCEST agent. Magn Reson Med 2015; 75:2432-41. [PMID: 26173637 DOI: 10.1002/mrm.25844] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 06/16/2015] [Accepted: 06/22/2015] [Indexed: 12/30/2022]
Abstract
PURPOSE This study explored the feasibility of using a pH responsive paramagnetic chemical exchange saturation transfer (paraCEST) agent to image the pH gradient in kidneys of healthy mice. METHODS CEST signals were acquired on an Agilent 9.4 Tesla small animal MRI system using a steady-state gradient echo pulse sequence after a bolus injection of agent. The magnetic field inhomogeneity across each kidney was corrected using the WASSR method and pH maps were calculated by measuring the frequency of water exchange signal arising from the agent. RESULTS Dynamic CEST studies demonstrated that the agent was readily detectable in kidneys only between 4 to 12 min postinjection. The CEST images showed a higher signal intensity in the pelvis and calyx regions and lower signal intensity in the medulla and cortex regions. The pH maps reflected tissue pH values spanning from 6.0 to 7.5 in kidneys of healthy mice. CONCLUSION This study demonstrated that pH maps of the kidney can be imaged in vivo by measuring the pH-dependent chemical shift of a single water exchange CEST peak without prior knowledge of the agent concentration in vivo. The results demonstrate the potential of using a simple frequency-dependent paraCEST agent for mapping tissue pH in vivo. Magn Reson Med 75:2432-2441, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Yunkou Wu
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center at Dallas, Texas, USA.,Department of Radiology, The University of Texas Southwestern Medical Center at Dallas, Texas, USA.,Department of Radiology, Howard University, Washington DC, USA
| | - Shanrong Zhang
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center at Dallas, Texas, USA
| | - Todd C Soesbe
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center at Dallas, Texas, USA.,Department of Radiology, The University of Texas Southwestern Medical Center at Dallas, Texas, USA
| | - Jing Yu
- Department of Chemistry, The University of Texas at Dallas, Richardson, Texas, USA
| | - Elena Vinogradov
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center at Dallas, Texas, USA.,Department of Radiology, The University of Texas Southwestern Medical Center at Dallas, Texas, USA
| | - Robert E Lenkinski
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center at Dallas, Texas, USA.,Department of Radiology, The University of Texas Southwestern Medical Center at Dallas, Texas, USA
| | - A Dean Sherry
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center at Dallas, Texas, USA.,Department of Radiology, The University of Texas Southwestern Medical Center at Dallas, Texas, USA.,Department of Chemistry, The University of Texas at Dallas, Richardson, Texas, USA
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69
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Abstract
Molecular imaging plays an important role in the era of personalized medicine, especially with recent advances in magnetic resonance (MR) probes. While the first generation of these probes focused on maximizing contrast enhancement, a second generation of probes has been developed to improve the accumulation within specific tissues or pathologies, and the newest generation of agents is also designed to report on changes in physiological status and has been termed "smart" agents. This represents a paradigm switch from the previously commercialized gadolinium and iron oxide probes to probes with new capabilities, and leads to new challenges as scanner hardware needs to be adapted for detecting these probes. In this chapter, we highlight the unique features for all five different categories of MR probes, including the emerging chemical exchange saturation transfer, (19)F, and hyperpolarized probes, and describe the key physical properties and features motivating their design. As part of this comparison, the strengths and weaknesses of each category are discussed.
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Affiliation(s)
- Michael T McMahon
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA; The Russell H. Morgan Department of Radiology and Radiological Sciences, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
| | - Kannie W Y Chan
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA; The Russell H. Morgan Department of Radiology and Radiological Sciences, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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70
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Bar-Shir A, Bulte JWM, Gilad AA. Molecular engineering of nonmetallic biosensors for CEST MRI. ACS Chem Biol 2015; 10:1160-70. [PMID: 25730583 DOI: 10.1021/cb500923v] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Recent advancements in molecular and synthetic biology, combined with synthetic chemistry and biotechnology, have opened up new opportunities to engineer novel platforms that can monitor complex biological processes with various noninvasive imaging modalities. After decades of using gadolinium- or iron-based metallic sensors for MRI, the recently developed chemical exchange saturation transfer (CEST) contrast mechanism has created an opportunity for rational design, in silico, of nonmetallic biosensors for MRI. These biomolecules are either naturally occurring compounds (amino acids, sugars, nucleosides, native proteins) or can be artificially engineered (synthetic probes or recombinant proteins). They can be administered either as exogenous agents or can be genetically (over)expressed. Moreover, they can be precisely engineered to achieve the desired biochemical properties for fine tuning optimized imaging schemes. The availability of these agents marks the dawn of a new scientific era for molecular and cellular MRI.
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Affiliation(s)
- Amnon Bar-Shir
- Russell
H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, United States
- Cellular
Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Jeff W. M. Bulte
- Russell
H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, United States
- Cellular
Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
- F.M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21205, United States
- Department
of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
- Department of Chemical & Biomolecular Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21218, United States
| | - Assaf A. Gilad
- Russell
H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, United States
- Cellular
Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
- F.M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21205, United States
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71
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Song X, Xu J, Xia S, Yadav NN, Lal B, Laterra J, Bulte JWM, van Zijl PCM, McMahon MT. Multi-echo length and offset VARied saturation (MeLOVARS) method for improved CEST imaging. Magn Reson Med 2014; 73:488-96. [PMID: 25516490 DOI: 10.1002/mrm.25567] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 11/14/2014] [Accepted: 11/14/2014] [Indexed: 12/15/2022]
Abstract
PURPOSE The aim of this study was to develop a technique for rapid collection of chemical exchange saturation transfer images with the saturation varied to modulate signal loss transfer and enhance contrast. METHODS Multi-echo Length and Offset VARied Saturation (MeLOVARS) divides the saturation pulse of length Tsat into N = 3-8 submodules, each consisting of a saturation pulse with length of Tsat /N (∼0.3-1 s), one or more low flip-angle gradient-echo readout(s) and a flip back pulse. This results in N readouts with increasing saturation time from Tsat /N to Tsat without extra scan time. RESULTS For phantoms, eight images with Tsat incremented every 0.5 s from 0.5-4 s were collected simultaneously using MeLOVARS, which allows rapid determination of exchange rates for agent protons. For live mice bearing glioblastomas, the Z-spectra for five different Tsat values from 0.5 to 2.5 s were acquired in a time normally used for one Tsat . With the additional Tsat -dependence information, LOVARS phase maps were produced with a more clearly defined tumor boundary and an estimated 4.3-fold enhanced contrast-to-noise ratio (CNR). We also show that enhancing CNR is achievable by simply averaging the collected images or transforming them using the principal component analysis. CONCLUSIONS MeLOVARS enables collection of multiple saturation-time-weighted images without extra time, producing a LOVARS phase map with increased CNR.
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Affiliation(s)
- Xiaolei Song
- Division of MR Research, The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
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72
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Yang X, Yadav NN, Song X, Banerjee SR, Edelman H, Minn I, van Zijl PCM, Pomper MG, McMahon MT. Tuning phenols with Intra-Molecular bond Shifted HYdrogens (IM-SHY) as diaCEST MRI contrast agents. Chemistry 2014; 20:15824-32. [PMID: 25302635 PMCID: PMC4309366 DOI: 10.1002/chem.201403943] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Indexed: 01/31/2023]
Abstract
The optimal exchange properties for chemical exchange saturation transfer (CEST) contrast agents on 3 T clinical scanners were characterized using continuous wave saturation transfer, and it was demonstrated that the exchangeable protons in phenols can be tuned to reach these criteria through proper ring substitution. Systematic modification allows the chemical shift of the exchangeable protons to be positioned between 4.8 to 12 ppm from water and enables adjustment of the proton exchange rate to maximize CEST contrast at these shifts. In particular, 44 hydrogen-bonded phenols are investigated for their potential as CEST MRI contrast agents and the stereoelectronic effects on their CEST properties are summarized. Furthermore, a pair of compounds, 2,5-dihydroxyterephthalic acid and 4,6-dihydroxyisophthalic acid, were identified which produce the highest sensitivity through incorporating two exchangeable protons per ring.
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Affiliation(s)
- Xing Yang
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, MD 21287 (USA)
| | - Nirbhay N. Yadav
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, MD 21287 (USA)
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 N. Broadway Ave. Baltimore, MD 21287 (USA)
| | - Xiaolei Song
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, MD 21287 (USA)
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 N. Broadway Ave. Baltimore, MD 21287 (USA)
| | - Sangeeta Ray Banerjee
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, MD 21287 (USA)
| | - Hannah Edelman
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, MD 21287 (USA)
| | - Il Minn
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, MD 21287 (USA)
| | - Peter C. M. van Zijl
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, MD 21287 (USA)
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 N. Broadway Ave. Baltimore, MD 21287 (USA)
| | - Martin G. Pomper
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, MD 21287 (USA)
| | - Michael T. McMahon
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, MD 21287 (USA)
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 N. Broadway Ave. Baltimore, MD 21287 (USA)
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73
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Song X, Yang X, Ray Banerjee S, Pomper MG, McMahon MT. Anthranilic acid analogs as diamagnetic CEST MRI contrast agents that feature an intramolecular-bond shifted hydrogen. CONTRAST MEDIA & MOLECULAR IMAGING 2014; 10:74-80. [PMID: 24771546 DOI: 10.1002/cmmi.1597] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 01/22/2014] [Accepted: 01/29/2014] [Indexed: 12/23/2022]
Abstract
Diamagnetic chemical exchange saturation transfer (diaCEST) agents are a new class of imaging agents, which have unique magnetic resonance (MR) properties similar to agents used for optical imaging. Here we present a series of anthranilic acid analogs as examples of diaCEST agents that feature an exchangeable proton shifted downfield, namely, an intramolecular-bond shifted hydrogen (IM-SHY), which produces significant and tunable contrast at frequencies of 4.8-9.3 ppm from water. Five analogs of N-sulfonyl anthranilic acids are all highly soluble and produced similar CEST contrast at ~6-8 ppm. We also discovered that flufenamic acid, a commercial nonsteroidal anti-inflammatory drug, displayed CEST contrast at 4.8 ppm. For these N-H IM-SHY agents, the contrast produced was insensitive to pH, making them complementary to existing diaCEST probes. This initial IM-SHY library includes the largest reported shifts for N-H protons on small organic diaCEST agents, and should find use as multifrequency MR agents for in vivo applications.
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Affiliation(s)
- Xiaolei Song
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
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