1
|
Rosa E, Di Gregorio E, Ferrauto G, Diaferia C, Gallo E, Terreno E, Accardo A. Hybrid PNA-peptide hydrogels as injectable CEST-MRI agents. J Mater Chem B 2024; 12:6371-6383. [PMID: 38864345 DOI: 10.1039/d4tb00358f] [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: 06/13/2024]
Abstract
The self-assembly of peptides and peptide analogues may be exploited to develop platforms for different biomedical applications, among which CEST-MRI (chemical exchange saturation transfer magnetic resonance imaging) represents one of the most attractive techniques to be explored as a novel metal-free contrast approach in imaging acquisitions. A lysine-containing peptide sequence (LIVAGK-NH2, named K2) was thus modified by insertion, at the N-terminus, of a peptide nucleic acid (PNA) base, leading to a primary amine suitable for the signal generation. a-K2, c-K2, g-K2 and t-K2 peptides were synthesized and characterized. The c-K2 sequence displayed gelling properties and the Watson and Crick pairing, arising from its combination with g-K2, allowed a significant increase in the mechanical responsivity of the hydrogel. These matrices were able to generate a CEST signal around 2.5 ppm from water and, after assessing their cytocompatibility on GL261 (murine glioma), TS/a (murine breast carcinoma), and 3T3-NIH (murine fibroblasts) cell lines, their capability to work as implants for in vivo detection, was proved by intratumor injection in Balb/c mice inoculated with TS/a murine breast cancer cells.
Collapse
Affiliation(s)
- Elisabetta Rosa
- Department of Pharmacy and Interuniversity Research Centre on Bioactive Peptides (CIRPeB) "Carlo Pedone", University of Naples "Federico II", Via D. Montesano 49, Naples 80131, Italy.
| | - Enza Di Gregorio
- Molecular and Preclinical Imaging Center, Department of Molecular Biotechnology and Health Sciences, University of Turin, Via Nizza 52, Turin, Italy.
| | - Giuseppe Ferrauto
- Molecular and Preclinical Imaging Center, Department of Molecular Biotechnology and Health Sciences, University of Turin, Via Nizza 52, Turin, Italy.
| | - Carlo Diaferia
- Department of Pharmacy and Interuniversity Research Centre on Bioactive Peptides (CIRPeB) "Carlo Pedone", University of Naples "Federico II", Via D. Montesano 49, Naples 80131, Italy.
| | - Enrico Gallo
- IRCCS Synlab SDN, Via Gianturco 113, Naples, 80143, Italy
| | - Enzo Terreno
- Molecular and Preclinical Imaging Center, Department of Molecular Biotechnology and Health Sciences, University of Turin, Via Nizza 52, Turin, Italy.
| | - Antonella Accardo
- Department of Pharmacy and Interuniversity Research Centre on Bioactive Peptides (CIRPeB) "Carlo Pedone", University of Naples "Federico II", Via D. Montesano 49, Naples 80131, Italy.
| |
Collapse
|
2
|
Sun PZ. Quasi-steady-state (QUASS) reconstruction enhances T 1 normalization in apparent exchange-dependent relaxation (AREX) analysis: A reevaluation of T 1 correction in quantitative CEST MRI of rodent brain tumor models. Magn Reson Med 2024; 92:236-245. [PMID: 38380727 PMCID: PMC11055669 DOI: 10.1002/mrm.30056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 01/26/2024] [Accepted: 02/04/2024] [Indexed: 02/22/2024]
Abstract
PURPOSE The apparent exchange-dependent relaxation (AREX) analysis has been proposed as an effective means to correct T1 contribution in CEST quantification. However, it has been recognized that AREX T1 correction is not straightforward if CEST scans are not performed under the equilibrium condition. Our study aimed to test if quasi-steady-state (QUASS) reconstruction could boost the accuracy of the AREX metric under common non-equilibrium scan conditions. THEORY AND METHODS Numerical simulation and in vivo scans were performed to assess the AREX metric accuracy. The CEST signal was simulated under different relaxation delays, RF saturation amplitudes, and durations. The AREX was evaluated as a function of the bulk water T1 and labile proton concentration using the multiple linear regression model. AREX MRI was also assessed in brain tumor rodent models, with both apparent CEST scans and QUASS reconstruction. RESULTS Simulation showed that the AREX calculation from apparent CEST scans, under non-equilibrium conditions, had significant dependence on labile proton fraction ratio, RF saturation time, and T1. In comparison, QUASS-boosted AREX depended on the labile proton fraction ratio without significant dependence on T1 and RF saturation time. Whereas the apparent (2.7 ± 0.8%) and QUASS MTR asymmetry (2.8 ± 0.8%) contrast between normal and tumor regions of interest (ROIs) were significant, the difference was small. In comparison, AREX contrast between normal and tumor ROIs calculated from the apparent CEST scan and QUASS reconstruction was 3.8 ± 1.1%/s and 4.4 ± 1.2%/s, respectively, statistically different from each other. CONCLUSIONS AREX analysis benefits from the QUASS-reconstructed equilibrium CEST effect for improved T1 correction and quantitative CEST analysis.
Collapse
Affiliation(s)
- Phillip Zhe Sun
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA
- Winship Cancer Institute, Emory University, Atlanta, GA
- Primate Imaging Center, Emory National Primate Research Center, Emory University, Atlanta, GA
| |
Collapse
|
3
|
Mohanta Z, Stabinska J, Gilad AA, Barker PB, McMahon MT. The Proton Resonance Enhancement for CEST imaging and Shift Exchange (PRECISE) family of RF pulse shapes for Chemical Exchange Saturation Transfer MRI. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.19.599565. [PMID: 38948741 PMCID: PMC11212941 DOI: 10.1101/2024.06.19.599565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Purpose To optimize a 100 msec pulse for producing CEST MRI contrast and evaluate in mice. Methods A gradient ascent algorithm was employed to generate a family of 100 point, 100 msec pulses for use in CEST pulse trains ('PRECISE'). Gradient ascent optimizations were performed for exchange rates (k ca ) = 500 s -1 , 1,500 s -1 , 2,500 s -1 , 3,500 s -1 and 4,500 s -1 and offsets (Δω) = 9.6, 7.8, 4.2 and 2.0 ppm. 7 PRECISE pulse shapes were tested on an 11.7 T scanner using a phantom containing three representative CEST agents with peak saturation B 1 = 4 μT. The pulse producing the most contrast in phantoms was then evaluated for CEST MRI pH mapping of the kidneys in healthy mice after iopamidol administration. Results The most promising pulse in terms of contrast performance across all three phantoms was the 9.6 ppm, 2500 s -1 optimized pulse with ∼2.7 x improvement over Gaussian and ∼1.3x's over Fermi pulses. This pulse also displayed a large improvement in contrast over the Gaussian pulse after administration of iopamidol in live mice. Conclusion A new 100 msec pulse was developed based on gradient ascent optimizations which produced better contrast compared to standard Gaussian and Fermi pulses in phantoms. This shape also showed a substantial improvement for CEST MRI pH mapping in live mice over the Gaussian shape and appears promising for a wide range of CEST applications.
Collapse
|
4
|
Ding L, Xu F, Luo B, Cheng L, Huang L, Jia Y, Ding J. Preparation of Hematoporphyrin-Poly(Lactic Acid) Nanoparticles Encapsulated Perfluoropentane/Salicylic Acid for Enhanced US/CEST MR Bimodal Imaging. Int J Nanomedicine 2024; 19:4589-4605. [PMID: 38799695 PMCID: PMC11127694 DOI: 10.2147/ijn.s454486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 05/07/2024] [Indexed: 05/29/2024] Open
Abstract
Background Medical imaging modalities, such as magnetic resonance imaging (MRI), ultrasound, and fluorescence imaging, have gained widespread acceptance in clinical practice for tumor diagnosis. Each imaging modality has its own unique principles, advantages, and limitations, thus necessitating a multimodal approach for a comprehensive disease understanding of the disease process. To enhance diagnostic precision, physicians frequently integrate data from multiple imaging modalities, driving research advancements in multimodal imaging technology research. Methods In this study, hematoporphyrin-poly (lactic acid) (HP-PLLA) polymer was prepared via ring-opening polymerization and thoroughly characterized using FT-IR, 1H-NMR, XRD, and TGA. HP-PLLA based nanoparticles encapsulating perfluoropentane (PFP) and salicylic acid were prepared via emulsion-solvent evaporation. Zeta potential and mean diameter were assessed using DLS and TEM. Biocompatibility was evaluated via cell migration, hemolysis, and cytotoxicity assays. Ultrasonic imaging was performed with a dedicated apparatus, while CEST MRI was conducted using a 7.0 T animal scanner. Results We designed and prepared a novel dual-mode nanoimaging probe SA/PFP@HP-PLLA NPs. PFP enhanced US imaging, while salicylic acid bolstered CEST imaging. With an average size of 74.43 ± 1.12 nm, a polydispersity index of 0.175 ± 0.015, and a surface zeta potential of -64.1 ± 2.11 mV. These NPs exhibit excellent biocompatibility and stability. Both in vitro and in vivo experiments confirmed the SA/PFP@HP-PLLA NP's ability to improve tumor characterization and diagnostic precision. Conclusion The SA/PFP@HP-PLLA NPs demonstrate promising dual-modality imaging capabilities, indicating their potential for preclinical and clinical use as a contrast agent.
Collapse
Affiliation(s)
- Liqiong Ding
- Xianning Medical College, Hubei University of Science and Technology, Xianning, Hubei Province, People’s Republic of China
| | - Fengnan Xu
- Xianning Medical College, Hubei University of Science and Technology, Xianning, Hubei Province, People’s Republic of China
| | - Binhua Luo
- Xianning Medical College, Hubei University of Science and Technology, Xianning, Hubei Province, People’s Republic of China
| | - Liyuan Cheng
- Xianning Medical College, Hubei University of Science and Technology, Xianning, Hubei Province, People’s Republic of China
| | - Lingping Huang
- Department of Medical Ultrasound, Xianning Central Hospital, The First Affiliated Hospital of Hubei University of Science and Technology, Xianning, Hubei Province, People’s Republic of China
| | - Yanlong Jia
- Department of Radiology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei Province, People’s Republic of China
| | - Jieqiong Ding
- Xianning Medical College, Hubei University of Science and Technology, Xianning, Hubei Province, People’s Republic of China
| |
Collapse
|
5
|
Zhuang C, Chen B, Wu S, Xu L, Zhang X, Zheng X, Chen Y, Geng Y, Guan J, Lin Y, Wilman AH, Wu R. Repurposing of the PET Probe Prototype PiB for Label and Radiation-Free CEST MRI Molecular Imaging of Amyloid. ACS Chem Neurosci 2023; 14:4344-4351. [PMID: 38061891 PMCID: PMC10741654 DOI: 10.1021/acschemneuro.3c00539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 11/21/2023] [Accepted: 11/22/2023] [Indexed: 12/21/2023] Open
Abstract
Positron emission tomography (PET) probes are specific and sensitive while suffering from radiation risk. It is worthwhile to explore the chemical emission saturation transfer (CEST) effects of the probe prototypes and repurpose them for CEST imaging to avoid radiation. In this study, we used 11C-PiB as an example of a PET probe for detecting amyloid and tested the feasibility of repurposing this PET probe prototype, PiB, for CEST imaging. After optimizing the parameters through preliminary phantom experiments, we used APP/PS1 transgenic mice and age-matched C57 mice for in vivo CEST magnetic resonance imaging (MRI) of amyloid. Furthermore, the pathological assessment was conducted on the same brain slices to evaluate the correlation between the CEST MRI signal abnormality and β-amyloid deposition detected by immunohistochemical staining. In our results, the Z-spectra revealed an apparent CEST effect that peaked at approximately 6 ppm. APP/PS1 mice as young as 9 months injected with PiB showed a significantly higher CEST effect compared to the control groups. The hyperintense region was correlated with the Aβ deposition shown by pathological staining. In conclusion, repurposing the PET probe prototype for CEST MRI imaging is feasible and enables label- and radiation-free detection of the amyloid while maintaining the sensitivity and specificity of the ligand. This study opens the door to developing CEST probes based on PET probe prototypes.
Collapse
Affiliation(s)
- Caiyu Zhuang
- Department
of Radiology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China
- Department
of Radiology, First Affiliated Hospital, Shantou University Medical College, Shantou 515041, China
| | - Beibei Chen
- Department
of Radiology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China
| | - Shuohua Wu
- Department
of Radiology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China
| | - Liang Xu
- Department
of Medical Imaging, Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen 518107, China
| | - Xiaolei Zhang
- Department
of Radiology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China
| | - Xinhui Zheng
- Department
of Radiology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China
| | - Yue Chen
- Department
of Radiology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China
| | - Yiqun Geng
- Laboratory
of Molecular Pathology, Shantou University
Medical College, Shantou 515041, China
| | - Jitian Guan
- Department
of Radiology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China
| | - Yan Lin
- Department
of Radiology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China
- Provincial
Key Laboratory for Breast Cancer Diagnosis and Treatment, Shantou 515041, China
| | - Alan H. Wilman
- The Department
of Biomedical Engineering, University of
Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Renhua Wu
- Department
of Radiology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China
- Provincial
Key Laboratory for Breast Cancer Diagnosis and Treatment, Shantou 515041, China
| |
Collapse
|
6
|
Ding J, He L, Yang L, Cheng L, Zhao Z, Luo B, Jia Y. Novel Nanoprobe with Combined Ultrasonography/Chemical Exchange Saturation Transfer Magnetic Resonance Imaging for Precise Diagnosis of Tumors. Pharmaceutics 2023; 15:2693. [PMID: 38140034 PMCID: PMC10747786 DOI: 10.3390/pharmaceutics15122693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 11/09/2023] [Accepted: 11/23/2023] [Indexed: 12/24/2023] Open
Abstract
Given that cancer mortality is usually due to a late diagnosis, early detection is crucial to improve the patient's results and prevent cancer-related death. Imaging technology based on novel nanomaterials has attracted much attention for early-stage cancer diagnosis. In this study, a new block copolymer, poly(ethylene glycol)-poly(l-lactide) diblock copolymer (PEG-PLLA), was synthesized by the ring-opening polymerization method and thoroughly characterized using Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (H-NMR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The obtained PEG-PLLA was used to prepare nanoparticles encapsulated with perfluoropentane and salicylic acid by the emulsion-solvent evaporation method, resulting in a new dual-mode nano-image probe (PEG-PLLA@SA·PFP). The zeta potential and mean diameter of the obtained nanoparticles were measured using dynamic light scattering (DLS) with a Malvern Zetersizer Nano. The in vitro biocompatibility of the PEG-PLLA nanoparticles was evaluated with cell migration, hemolysis, and cytotoxicity assays. Ultrasonic imaging was performed using an ultrasonic imaging apparatus, and chemical exchange saturation transfer (CEST) MRI was conducted on a 7.0 T animal scanner. The results of IR and NMR confirmed that the PEG-PLLA was successfully synthesized. The particle size and negative charge of the nanoparticles were 223.8 ± 2.5 nm and -39.6 ± 1.9 mV, respectively. The polydispersity of the diameter was 0.153 ± 0.020. These nanoparticles possessed good stability at 4 °C for about one month. The results of cytotoxicity, cell migration, and hemolysis assays showed that the carrier material was biocompatible. Finally, PEG-PLLA nanoparticles were able to significantly enhance the imaging effect of tumors by the irradiation of ultrasound and saturation by a radiofrequency pulse, respectively. In conclusion, these nanoparticles exhibit promising dual-mode capabilities for US/CEST MR imaging.
Collapse
Affiliation(s)
- Jieqiong Ding
- Xianning Medical College, Hubei University of Science and Technology, Xianning 437100, China; (J.D.); (L.H.); (L.C.)
| | - Liu He
- Xianning Medical College, Hubei University of Science and Technology, Xianning 437100, China; (J.D.); (L.H.); (L.C.)
| | - Lin Yang
- Department of Radiology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China;
| | - Liyuan Cheng
- Xianning Medical College, Hubei University of Science and Technology, Xianning 437100, China; (J.D.); (L.H.); (L.C.)
| | - Zhiwei Zhao
- Department of Radiology, Xianning Central Hospital, The First Affiliated Hospital of Hubei University of Science and Technology, Xianning 437100, China;
| | - Binhua Luo
- Xianning Medical College, Hubei University of Science and Technology, Xianning 437100, China; (J.D.); (L.H.); (L.C.)
| | - Yanlong Jia
- Department of Radiology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang 441021, China
| |
Collapse
|
7
|
Łopuszyńska N, Węglarz WP. Contrasting Properties of Polymeric Nanocarriers for MRI-Guided Drug Delivery. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2163. [PMID: 37570481 PMCID: PMC10420849 DOI: 10.3390/nano13152163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 07/20/2023] [Accepted: 07/20/2023] [Indexed: 08/13/2023]
Abstract
Poor pharmacokinetics and low aqueous solubility combined with rapid clearance from the circulation of drugs result in their limited effectiveness and generally high therapeutic doses. The use of nanocarriers for drug delivery can prevent the rapid degradation of the drug, leading to its increased half-life. It can also improve the solubility and stability of drugs, advance their distribution and targeting, ensure a sustained release, and reduce drug resistance by delivering multiple therapeutic agents simultaneously. Furthermore, nanotechnology enables the combination of therapeutics with biomedical imaging agents and other treatment modalities to overcome the challenges of disease diagnosis and therapy. Such an approach is referred to as "theranostics" and aims to offer a more patient-specific approach through the observation of the distribution of contrast agents that are linked to therapeutics. The purpose of this paper is to present the recent scientific reports on polymeric nanocarriers for MRI-guided drug delivery. Polymeric nanocarriers are a very broad and versatile group of materials for drug delivery, providing high loading capacities, improved pharmacokinetics, and biocompatibility. The main focus was on the contrasting properties of proposed polymeric nanocarriers, which can be categorized into three main groups: polymeric nanocarriers (1) with relaxation-type contrast agents, (2) with chemical exchange saturation transfer (CEST) properties, and (3) with direct detection contrast agents based on fluorinated compounds. The importance of this aspect tends to be downplayed, despite its being essential for the successful design of applicable theranostic nanocarriers for image-guided drug delivery. If available, cytotoxicity and therapeutic effects were also summarized.
Collapse
Affiliation(s)
- Natalia Łopuszyńska
- Department of Magnetic Resonance Imaging, Institute of Nuclear Physics Polish Academy of Sciences, 31-342 Cracow, Poland
| | - Władysław P. Węglarz
- Department of Magnetic Resonance Imaging, Institute of Nuclear Physics Polish Academy of Sciences, 31-342 Cracow, Poland
| |
Collapse
|
8
|
Longo DL, Carella A, Corrado A, Pirotta E, Mohanta Z, Singh A, Stabinska J, Liu G, McMahon MT. A snapshot of the vast array of diamagnetic CEST MRI contrast agents. NMR IN BIOMEDICINE 2023; 36:e4715. [PMID: 35187749 PMCID: PMC9724179 DOI: 10.1002/nbm.4715] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/17/2022] [Accepted: 02/18/2022] [Indexed: 05/11/2023]
Abstract
Since the inception of CEST MRI in the 1990s, a number of compounds have been identified as suitable for generating contrast, including paramagnetic lanthanide complexes, hyperpolarized atom cages and, most interesting, diamagnetic compounds. In the past two decades, there has been a major emphasis in this field on the identification and application of diamagnetic compounds that have suitable biosafety profiles for usage in medical applications. Even in the past five years there has been a tremendous growth in their numbers, with more and more emphasis being placed on finding those that can be ultimately used for patient studies on clinical 3 T scanners. At this point, a number of endogenous compounds present in tissue have been identified, and also natural and synthetic organic compounds that can be administered to highlight pathology via CEST imaging. Here we will provide a very extensive snapshot of the types of diamagnetic compound that can generate CEST MRI contrast, together with guidance on their utility on typical preclinical and clinical scanners and a review of the applications that might benefit the most from this new technology.
Collapse
Affiliation(s)
- Dario Livio Longo
- Institute of Biostructures and Bioimaging (IBB), National Research Council of Italy (CNR), Turin, Italy
| | - Antonella Carella
- Institute of Biostructures and Bioimaging (IBB), National Research Council of Italy (CNR), Turin, Italy
| | - Alessia Corrado
- Institute of Biostructures and Bioimaging (IBB), National Research Council of Italy (CNR), Turin, Italy
| | - Elisa Pirotta
- Institute of Biostructures and Bioimaging (IBB), National Research Council of Italy (CNR), Turin, Italy
| | - Zinia Mohanta
- F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Aruna Singh
- F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Julia Stabinska
- F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Guanshu Liu
- F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Michael T. McMahon
- F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| |
Collapse
|
9
|
Knutsson L, Xu X, van Zijl PCM, Chan KWY. Imaging of sugar-based contrast agents using their hydroxyl proton exchange properties. NMR IN BIOMEDICINE 2023; 36:e4784. [PMID: 35665547 PMCID: PMC9719573 DOI: 10.1002/nbm.4784] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 05/30/2022] [Accepted: 06/03/2022] [Indexed: 05/13/2023]
Abstract
The ability of CEST MRI to detect the presence of millimolar concentrations of non-metallic contrast agents has made it possible to study, non-invasively, important biological molecules such as proteins and sugars, as well as drugs already approved for clinical use. Here, we review efforts to use sugar and sugar polymers as exogenous contrast agents, which is possible based on the exchange of their hydroxyl protons with water protons. While this capability has raised early enthusiasm, for instance about the possibility of imaging D-glucose metabolism with MRI in a way analogous to PET, experience over the past decade has shown that this is not trivial. On the other hand, many studies have confirmed the possibility of imaging a large variety of sugar analogues, each with potentially interesting applications to assess tissue physiology. Some promising applications are the study of (i) sugar delivery and transport to assess blood-brain barrier integrity and (ii) sugar uptake by cells for their characterization (e.g., cancer versus healthy), as well as (iii) clearance of sugars to assess tissue drainage-for instance, through the glymphatic system. To judge these opportunities and their challenges, especially in the clinic, it is necessary to understand the technical aspects of detecting the presence of rapidly exchanging protons through the water signal in MRI, especially as a function of magnetic field strength. We expect that novel approaches in terms of MRI detection (both saturation transfer and relaxation based), MRI data analysis, and sugar design will push this young field forward in the next decade.
Collapse
Affiliation(s)
- Linda Knutsson
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, US
| | - Xiang Xu
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine
- BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Peter CM van Zijl
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, US
| | - Kannie WY Chan
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
- Hong Kong Centre for Cerebro-Cardiovascular Health Engineering, Hong Kong, China
- Tung Biomedical Sciences Centre, City University of Hong Kong
- City University of Hong Kong Shenzhen Institute, Shenzhen, China
| |
Collapse
|
10
|
Gilad AA, Bar-Shir A, Bricco AR, Mohanta Z, McMahon MT. Protein and peptide engineering for chemical exchange saturation transfer imaging in the age of synthetic biology. NMR IN BIOMEDICINE 2023; 36:e4712. [PMID: 35150021 PMCID: PMC10642350 DOI: 10.1002/nbm.4712] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 02/02/2022] [Accepted: 02/05/2022] [Indexed: 05/23/2023]
Abstract
At the beginning of the millennium, the first chemical exchange saturation transfer (CEST) contrast agents were bio-organic molecules. However, later, metal-based CEST agents (paraCEST agents) took center stage. This did not last too long as paraCEST agents showed limited translational potential. By contrast, the CEST field gradually became dominated by metal-free CEST agents. One branch of research stemming from the original work by van Zijl and colleagues is the development of CEST agents based on polypeptides. Indeed, in the last 2 decades, tremendous progress has been achieved in this field. This includes the design of novel peptides as biosensors, genetically encoded recombinant as well as synthetic reporters. This was a result of extensive characterization and elucidation of the theoretical requirements for rational designing and engineering of such agents. Here, we provide an extensive overview of the evolution of more precise protein-based CEST agents, review the rationalization of enzyme-substrate pairs as CEST contrast enhancers, discuss the theoretical considerations to improve peptide selectivity, specificity and enhance CEST contrast. Moreover, we discuss the strong influence of synthetic biology on the development of the next generation of protein-based CEST contrast agents.
Collapse
Affiliation(s)
- Assaf A. Gilad
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan, USA
- Department of Radiology, Michigan State University, East Lansing, Michigan, USA
| | - Amnon Bar-Shir
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, Israel
| | - Alexander R. Bricco
- Department of Biomedical Engineering, Michigan State University, East Lansing, Michigan, USA
| | - Zinia Mohanta
- 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
| | - Michael T. McMahon
- 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
| |
Collapse
|
11
|
Bo S, Stabinska J, Wu Y, Pavuluri K, Singh A, Mohanta Z, Choudhry R, Kates M, Sedaghat F, Bhujwalla Z, Pomper MG, McMahon MT. Exploring the potential of the novel imidazole-4,5-dicarboxyamide chemical exchange saturation transfer scaffold for pH and perfusion imaging. NMR IN BIOMEDICINE 2023; 36:e4894. [PMID: 36543742 PMCID: PMC10200726 DOI: 10.1002/nbm.4894] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 12/12/2022] [Accepted: 12/20/2022] [Indexed: 05/23/2023]
Abstract
Here, we describe and assess the potential of 14 newly synthesized imidazole-4,5-dicarboxyamides (I45DCs) for pH and perfusion imaging. A number of these aromatic compounds possess large labile proton chemical shifts (up to 7.7 ppm from water) because of their intramolecular hydrogen bonds and a second labile proton to allow for chemical exchange saturation transfer (CEST) signal ratio-based pH measurements. We have found that the contrast produced is strong for a wide range of substitutions and that the inflection points in the CEST signal ratio versus pH plots used to generate concentration-independent pH maps can be adjusted based on these subsitutions to tune the pH range that can be measured. These I45DC CEST agents have advantages over the triiodobenzenes currently employed for tumor and kidney pH mapping, both preclinically and in initial human studies. Finally, as CEST MRI combined with exogenous contrast has the potential to detect functional changes in the kidneys, we evaluated our highest performing anionic compound (I45DC-diGlu) on a unilateral urinary obstruction mouse model and observed lower contrast uptake in the obstructed kidney compared with the unobstructed kidney and that the unobstructed kidney displayed a pH of ~ 6.5 while the obstructed kidney had elevated pH and an increased range in pH values. Based on this, we conclude that the I45DCs have excellent imaging properties and hold promise for a variety of medical imaging applications, particularly renal imaging.
Collapse
Affiliation(s)
- Shaowei Bo
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Julia Stabinska
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD
| | - Yunkou Wu
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - KowsalyaDevi Pavuluri
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Aruna Singh
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD
| | - Zinia Mohanta
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD
| | - Rehan Choudhry
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Max Kates
- The James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Farzad Sedaghat
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Zaver Bhujwalla
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Martin G. Pomper
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD
- The James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Michael T. McMahon
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD
| |
Collapse
|
12
|
Bo S, Zhang D, Ma M, Mo X, Stabinska J, McMahon MT, Shi C, Luo L. Acyl Hydrazides and Acyl Hydrazones as High-Performance Chemical Exchange Saturation Transfer MRI Contrast Agents. Pharmaceuticals (Basel) 2023; 16:ph16050639. [PMID: 37242423 DOI: 10.3390/ph16050639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/17/2023] [Accepted: 04/20/2023] [Indexed: 05/28/2023] Open
Abstract
Chemical exchange saturation transfer (CEST) MRI is a versatile molecular imaging approach that holds great promise for clinical translation. A number of compounds have been identified as suitable for performing CEST MRI, including paramagnetic CEST (paraCEST) agents and diamagnetic CEST (diaCEST) agents. DiaCEST agents are very attractive because of their excellent biocompatibility and potential for biodegradation, such as glucose, glycogen, glutamate, creatine, nucleic acids, et al. However, the sensitivity of most diaCEST agents is limited because of small chemical shifts (1.0-4.0 ppm) from water. To expand the catalog of diaCEST agents with larger chemical shifts, herein, we have systematically investigated the CEST properties of acyl hydrazides with different substitutions, including aromatic and aliphatic substituents. We have tuned the labile proton chemical shifts from 2.8-5.0 ppm from water while exchange rates varied from ~680 to 2340 s-1 at pH 7.2, which allows strong CEST contrast on scanners down to B0 = 3 T. One acyl hydrazide, adipic acid dihydrazide (ADH), was tested on a mouse model of breast cancer and showed nice contrast in the tumor region. We also prepared a derivative, acyl hydrazone, which showed the furthest shifted labile proton (6.4 ppm from water) and excellent contrast properties. Overall, our study expands the catalog of diaCEST agents and their application in cancer diagnosis.
Collapse
Affiliation(s)
- Shaowei Bo
- Department of Medical Imaging, The Affiliated Guangdong Second Provincial General Hospital of Jinan University, Guangzhou 510317, China
| | - Dong Zhang
- Medical Imaging Center, The First Affiliated Hospital of Jinan University, Guangzhou 510632, China
| | - Mengjie Ma
- Medical Imaging Center, The First Affiliated Hospital of Jinan University, Guangzhou 510632, China
| | - Xukai Mo
- Medical Imaging Center, The First Affiliated Hospital of Jinan University, Guangzhou 510632, China
| | - Julia Stabinska
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21287, USA
| | - Michael T McMahon
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21287, USA
| | - Changzheng Shi
- Medical Imaging Center, The First Affiliated Hospital of Jinan University, Guangzhou 510632, China
| | - Liangping Luo
- Department of Medical Imaging, The Affiliated Guangdong Second Provincial General Hospital of Jinan University, Guangzhou 510317, China
- Medical Imaging Center, The First Affiliated Hospital of Jinan University, Guangzhou 510632, China
| |
Collapse
|
13
|
Pandey S, Ghosh R, Ghosh A. Preparation of Hydrothermal Carbon Quantum Dots as a Contrast Amplifying Technique for the diaCEST MRI Contrast Agents. ACS OMEGA 2022; 7:33934-33941. [PMID: 36188278 PMCID: PMC9520682 DOI: 10.1021/acsomega.2c02911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 08/30/2022] [Indexed: 06/16/2023]
Abstract
The discovery of exogenous contrast agents (CAs) is one of the key factors behind the success and widespread acceptability of MRI as an imaging tool. To the long list of CAs, the newest addition is the chemical exchange saturation transfer (CEST)-based CAs. Among them, the diaCEST CAs are the safer metal-free option constituted by a large pool of organic and macromolecules, but the tradeoff comes in terms of smaller natural offset. Another major challenge for the CEST CAs is that they need to operate in the tens of millimolar concentration range to produce any meaningful contrast. The quest for high efficiency diaCEST agents has led to a number of strategies such as use of hydrogen bonding, use of equivalent protons, and use of diatropic ring current. Here, we present carbon quantum dot formation using hydrothermal treatment as a new strategy to amplify diaCEST contrast efficiency. We show that while the well-known analgesic drug lidocaine hydrochloride when repurposed as a diaCEST CA produces no contrast at the physiological pH and temperature, the carbon dots prepared from it elevate the physiological contrast to a sizable 11%. Also, the maximum efficiency at an acidic pH gets amplified by a factor of 2 to 46%. The study showed that the enhancement in CEST efficiency is reproducible and the pH response of these carbon dots is tunable through variation in synthesis conditions such as temperature, duration, and precursor concentration.
Collapse
|
14
|
Zhao Y, Zu Z, Xu J, Gore JC, Does MD, Li J, Gochberg DF. Mapping pH using stimulated echoes formed via chemical exchange. Magn Reson Imaging 2022; 92:100-107. [PMID: 35764217 DOI: 10.1016/j.mri.2022.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 06/10/2022] [Accepted: 06/22/2022] [Indexed: 12/09/2022]
Abstract
PURPOSE RACETE (refocused acquisition of chemical exchange transferred excitations) is a recently developed approach to imaging solute exchange with water. However, it lacks biophysical specificity, as it is sensitive to exchange rates, relaxation rates, solute concentration, and macromolecular content. We modified this sequence and developed a protocol and corresponding metric with specific sensitivity to the solute exchange rate and hence a means for mapping pH. THEORY AND METHODS RACETE splits the two gradients traditionally used in a stimulated-echo sequence into one applied after exciting solutes and one applied after exciting water, hence requiring exchange for echo formation. In this work, we leverage the dependence of the stimulated-echo signal on the exchange process. By preserving the total irradiation power and using a ratio metric, the other signal dependencies cancel, leaving a specific measure of exchange rate. Additionally, artifacts due to off-resonance excitation of water are addressed using a phase cancelling approach; and a gradient-echo imaging sequence with a variable flip angle excitation is tailored for a fast read-out of RECETE prepared signals. This method is validated using numerical simulations and salicylic acid phantom experiments at 9.4 T. RESULTS Numerical simulations and phantom experiments demonstrate that the ratio-metric is a single-variable function of exchange rate with extremely low dependence on confounding factors. Additionally, artifacts due to direct water excitation are removed and robustness to B0 and B1 inhomogeneities is demonstrated. CONCLUSION The proposed method can be used for fast pH mapping with robustness against the confounding effects that widely exist in other methods.
Collapse
Affiliation(s)
- Yu Zhao
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai, China
| | - Zhongliang Zu
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Junzhong Xu
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
| | - John C Gore
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Mark D Does
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jianqi Li
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai, China
| | - Daniel F Gochberg
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA.
| |
Collapse
|
15
|
Pavuluri K, Yang E, Ayyappan V, Sonkar K, Tan Z, Tressler CM, Bo S, Bibic A, Glunde K, McMahon MT. Unlabeled aspirin as an activatable theranostic MRI agent for breast cancer. Theranostics 2022; 12:1937-1951. [PMID: 35198081 PMCID: PMC8825591 DOI: 10.7150/thno.53147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 11/17/2021] [Indexed: 01/11/2023] Open
Abstract
Rationale: Chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) is emerging as an alternative to gadolinium-based contrast MRI. We have evaluated the possibility of CEST MRI of orthotopic breast tumor xenografts with unlabeled aspirin's conversion to salicylic acid (SA) through various enzymatic activities, most notably inhibition of cyclooxygenase (COX)-1/-2 enzymes. Methods: We measured the COX-1/-2 expression in four breast cancer cell lines by Western Blot analysis and selected the highest and lowest expressing cell lines. We then performed CEST MRI following aspirin treatment to detect SA levels and ELISA to measure levels of downstream prostaglandin E2 (PGE2). We also injected aspirin into the tail vein of mice growing orthotopic tumor xenografts which expressed high and low COX-1/-2 and acquired SA CEST MR images of these tumor xenografts for up to 70 minutes. Tumors were then harvested to perform Western Blot and ELISA experiments to measure COX-1/-2 expression and PGE2 levels, respectively. Results: Western Blots determined that SUM159 cells contained significantly higher COX-1/-2 expression levels than MDA-MB-231 cells, in line with higher levels of downstream PGE2. SA CEST MRI yielded similar contrast at approximately 3% for both cell lines, independent of COX-1/-2 expression level. PGE2 levels decreased by about 50% following aspirin treatment. Results from our mouse study aligned with cultured cells, the overall SA CEST MRI contrast in both MDA-MB-231 and SUM159 tumor xenograft models was 5~8% at one hour post injection. PGE2 levels were ten times higher in SUM159 than MDA-MB-231 and decreased by 50%. The CEST contrast directly depended on the injected dose, with ~6%, ~3% and ~1.5% contrast observed following injection of 100 µL of 300 mM, 200 mM and 150 mM aspirin, respectively. Conclusions: Our data demonstrate the feasibility of using aspirin as a noninvasive activatable CEST MRI contrast agent for breast tumor detection.
Collapse
Affiliation(s)
- KowsalyaDevi Pavuluri
- Division of MR Research, The Russell H. Morgan Department of Radiology and Radiological Science; The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Ethan Yang
- Division of Cancer Imaging Research, The Russell H. Morgan Department of Radiology and Radiological Science; The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Vinay Ayyappan
- Division of Cancer Imaging Research, The Russell H. Morgan Department of Radiology and Radiological Science; The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Kanchan Sonkar
- Division of Cancer Imaging Research, The Russell H. Morgan Department of Radiology and Radiological Science; The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Zheqiong Tan
- Division of Cancer Imaging Research, The Russell H. Morgan Department of Radiology and Radiological Science; The Johns Hopkins University School of Medicine, Baltimore, MD.,Department of Medical Laboratory, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Caitlin M. Tressler
- Division of Cancer Imaging Research, The Russell H. Morgan Department of Radiology and Radiological Science; The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Shaowei Bo
- Division of MR Research, The Russell H. Morgan Department of Radiology and Radiological Science; The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Adnan Bibic
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD
| | - Kristine Glunde
- Division of Cancer Imaging Research, The Russell H. Morgan Department of Radiology and Radiological Science; The Johns Hopkins University School of Medicine, Baltimore, MD.,The Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD.,Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD.,✉ Corresponding authors: ,
| | - Michael T McMahon
- Division of MR Research, The Russell H. Morgan Department of Radiology and Radiological Science; The Johns Hopkins University School of Medicine, Baltimore, MD.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD.,✉ Corresponding authors: ,
| |
Collapse
|
16
|
Kombala CJ, Kotrotsou A, Schuler FW, de la Cerda J, Ma JC, Zhang S, Pagel MD. Development of a Nanoscale Chemical Exchange Saturation Transfer Magnetic Resonance Imaging Contrast Agent That Measures pH. ACS NANO 2021; 15:20678-20688. [PMID: 34870957 DOI: 10.1021/acsnano.1c10107] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
AcidoCEST MRI can measure the extracellular pH (pHe) of the tumor microenvironment in mouse models of human cancers and in patients who have cancer. However, chemical exchange saturation transfer (CEST) is an insensitive magnetic resonance imaging (MRI) contrast mechanism, requiring a high concentration of small-molecule agent to be delivered to the tumor. Herein, we developed a nanoscale CEST agent that can measure pH using acidoCEST MRI, which may decrease the requirement for high delivery concentrations of agent. We also developed a monomer agent for comparison to the polymer. After optimizing CEST experimental conditions, we determined that the polymer agent could be used during acidoCEST MRI studies at 125-fold and 488-fold lower concentration than the monomer agent and iopamidol, respectively. We also determined that both agents can measure pH with negligible dependence on temperature. However, pH measurements with both agents were dependent on concentration, which may be due to concentration-dependent changes in hydrogen bonding and/or steric hindrance. We performed in vivo acidoCEST MRI studies using the three agents to study a xenograft MDA-MB-231 model of mammary carcinoma. The tumor pHe measurements were 6.33 ± 0.12, 6.70 ± 0.15, and 6.85 ± 0.15 units with iopamidol, the monomer agent, and polymer agent, respectively. The higher pHe measurements with the monomer and polymer agents were attributed to the concentration dependence of these agents. This study demonstrated that nanoscale agents have merit for CEST MRI studies, but consideration should be given to the dependence of CEST contrast on the concentration of these agents.
Collapse
Affiliation(s)
- Chathuri J Kombala
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, Texas 77054, United States
| | - Aikaterini Kotrotsou
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, Texas 77054, United States
| | - F William Schuler
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, Texas 77054, United States
| | - Jorge de la Cerda
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, Texas 77054, United States
| | - Jacqueline C Ma
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, Texas 77054, United States
| | - Shu Zhang
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, Texas 77054, United States
| | - Mark D Pagel
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, Texas 77054, United States
| |
Collapse
|
17
|
Brun EMSPT, Calvert ND, Suchý M, Kirby A, Melkus G, Garipov R, Addison CL, Shuhendler AJ. Mapping vitamin B 6 metabolism by hydrazoCEST magnetic resonance imaging. Chem Commun (Camb) 2021; 57:10867-10870. [PMID: 34665184 DOI: 10.1039/d1cc03704h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new CEST-MRI contrast agent, 2-HYNIC, capable of sensing aromatic aldehydes is reported. Pyridoxal 5'-phosphate, a key Vitamin B6 metabolite necessary for >140 biotransformations was mapped by CEST-MRI in vitro and in vivo in lung cancer. 2-HYNIC provided access to this key biomarker associated with a variety of human diseases.
Collapse
Affiliation(s)
- Emilie Marie Sophie Patit-Tha Brun
- Dept. Chemistry & Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, Canada. .,University of Ottawa Heart Institute, Ottawa, Ontario, Canada
| | - Nicholas David Calvert
- Dept. Chemistry & Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, Canada. .,University of Ottawa Heart Institute, Ottawa, Ontario, Canada
| | - Mojmír Suchý
- Dept. Chemistry & Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, Canada. .,University of Ottawa Heart Institute, Ottawa, Ontario, Canada
| | - Alexia Kirby
- University of Ottawa Heart Institute, Ottawa, Ontario, Canada.,Dept. Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Gerd Melkus
- Dept. Medical Imaging, The Ottawa Hospital, Ottawa, ON, Canada.,Dept. Radiology, University of Ottawa, Ottawa, Ontario, Canada
| | | | - Christina L Addison
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Canada.,Dept. Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada.,Dept. Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Adam J Shuhendler
- Dept. Chemistry & Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, Canada. .,University of Ottawa Heart Institute, Ottawa, Ontario, Canada.,Dept. Biology, University of Ottawa, Ottawa, Ontario, Canada
| |
Collapse
|
18
|
Zhao W, Yu X, Peng S, Luo Y, Li J, Lu L. Construction of nanomaterials as contrast agents or probes for glioma imaging. J Nanobiotechnology 2021; 19:125. [PMID: 33941206 PMCID: PMC8091158 DOI: 10.1186/s12951-021-00866-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 04/20/2021] [Indexed: 02/06/2023] Open
Abstract
Malignant glioma remains incurable largely due to the aggressive and infiltrative nature, as well as the existence of blood-brain-barrier (BBB). Precise diagnosis of glioma, which aims to accurately delineate the tumor boundary for guiding surgical resection and provide reliable feedback of the therapeutic outcomes, is the critical step for successful treatment. Numerous imaging modalities have been developed for the efficient diagnosis of tumors from structural or functional aspects. However, the presence of BBB largely hampers the entrance of contrast agents (Cas) or probes into the brain, rendering the imaging performance highly compromised. The development of nanomaterials provides promising strategies for constructing nano-sized Cas or probes for accurate imaging of glioma owing to the BBB crossing ability and other unique advantages of nanomaterials, such as high loading capacity and stimuli-responsive properties. In this review, the recent progress of nanomaterials applied in single modal imaging modality and multimodal imaging for a comprehensive diagnosis is thoroughly summarized. Finally, the prospects and challenges are offered with the hope for its better development.
Collapse
Affiliation(s)
- Wei Zhao
- Zhuhai Precision Medical Center, Zhuhai Interventional Medical Center, Zhuhai People's Hospital (Affiliated With Jinan University), Zhuhai, 519000, Guangdong, China
| | - Xiangrong Yu
- Zhuhai Precision Medical Center, Zhuhai Interventional Medical Center, Zhuhai People's Hospital (Affiliated With Jinan University), Zhuhai, 519000, Guangdong, China
| | - Shaojun Peng
- Zhuhai Precision Medical Center, Zhuhai Interventional Medical Center, Zhuhai People's Hospital (Affiliated With Jinan University), Zhuhai, 519000, Guangdong, China
| | - Yu Luo
- School of Chemical Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, China.
| | - Jingchao Li
- College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai, 201620, China.
| | - Ligong Lu
- Zhuhai Precision Medical Center, Zhuhai Interventional Medical Center, Zhuhai People's Hospital (Affiliated With Jinan University), Zhuhai, 519000, Guangdong, China.
| |
Collapse
|
19
|
Mamoune KE, Barantin L, Adriaensen H, Tillet Y. Application of Chemical Exchange Saturation Transfer (CEST) in neuroimaging. J Chem Neuroanat 2021; 114:101944. [PMID: 33716103 DOI: 10.1016/j.jchemneu.2021.101944] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 03/02/2021] [Accepted: 03/04/2021] [Indexed: 12/14/2022]
Abstract
Since the early eighties MRI has become the most powerful technic for in-vivo imaging particularly in the field of brain research. This non-invasive method allows acute anatomical observations of the living brain similar to post-mortem dissected tissues. However, one of the main limitation of MRI is that it does not make possible the neurochemical identification of the tissues conversely to positron emission tomography scanner which can provide a specific molecular characterization of tissue, in spite of poor anatomical definition. To gain neurochemical information using MRI, new categories of contrast agents were developed from the beginning of the 2000's, particularly using the chemical-exchange saturation transfer (CEST) method. This method induces a significant change in the magnitude of the water proton signal and allows the detection of specific molecules within the tissues like sugars, amino acids, transmitters, and nucleosides. This short review presents several CEST contrast agents and their recent developments for in vivo detection of metabolites and neurotransmitters in the brain for research and clinical purposes.
Collapse
Affiliation(s)
- Kahina El Mamoune
- Physiologie de la Reproduction et des Comportements, UMR 085 INRAE, CNRS 7247, Université de Tours, IFCE, Centre INRAE Val de Loire, 37380 Nouzilly, France; Siemens Healthcare SAS, Saint Denis, France; SFR FED 4226, Université de Tours, 2 Bd Tonnellé, 37032 Tours, France
| | - Laurent Barantin
- iBrain, UMR 1253 INSERM, Université de Tours, 10 Bd Tonnellé, 37032 Tours, France; SFR FED 4226, Université de Tours, 2 Bd Tonnellé, 37032 Tours, France
| | - Hans Adriaensen
- Physiologie de la Reproduction et des Comportements, UMR 085 INRAE, CNRS 7247, Université de Tours, IFCE, Centre INRAE Val de Loire, 37380 Nouzilly, France; CIRE UMR 085 INRAE, CNRS 7247, Université de Tours, IFCE, Centre INRAE Val de Loire, 37380 Nouzilly, France; SFR FED 4226, Université de Tours, 2 Bd Tonnellé, 37032 Tours, France
| | - Yves Tillet
- Physiologie de la Reproduction et des Comportements, UMR 085 INRAE, CNRS 7247, Université de Tours, IFCE, Centre INRAE Val de Loire, 37380 Nouzilly, France; SFR FED 4226, Université de Tours, 2 Bd Tonnellé, 37032 Tours, France.
| |
Collapse
|
20
|
Abstract
Mounting evidence shows the great promise of nanoparticle drug delivery systems (nano-DDSs) to improve delivery efficiency and reduce off-target adverse effects. By tracking drug delivery and distribution, monitoring nanoparticle degradation and drug release, aiding and optimizing treatment planning, and directing the design of more robust nano-DDSs, image guidance has become a vital component of nanomedicine. Recently, chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) has emerged as an attempting imaging method for achieving image-guided drug delivery. One of the unbeatable advantages of CEST MRI is its ability to detect diamagnetic compounds that cannot be detected using conventional MRI methods, making a broad spectrum of bioorganic agents, natural compounds, even nano-carriers directly MRI detectable in a high-spatial-resolution manner. To date, CEST MRI has become a versatile and powerful imaging technology for non-invasive in vivo tracking of nanoparticles and their loaded drugs. In this review, we will provide a concise overview of different forms of recently developed, CEST MRI trackable nano-DDSs, including liposomes, polymeric nanoparticles, self-assembled drug-based nanoparticles, and carbon dots. The potential applications and future perspectives will also be discussed.
Collapse
Affiliation(s)
- Zheng Han
- Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | | |
Collapse
|
21
|
Chakraborty S, Peruncheralathan S, Ghosh A. Paracetamol and other acetanilide analogs as inter-molecular hydrogen bonding assisted diamagnetic CEST MRI contrast agents. RSC Adv 2021; 11:6526-6534. [PMID: 35423188 PMCID: PMC8694904 DOI: 10.1039/d0ra10410h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 01/29/2021] [Indexed: 12/12/2022] Open
Abstract
Paracetamol and a few other acetanilide derivatives are reported as a special class of diamagnetic Chemical Exchange Saturation Transfer (diaCEST) MRI contrast agents, that exhibit contrast only when the molecules form inter-molecular hydrogen bonding mediated molecular chains or sheets. Without the protection of the hydrogen bonding their contrast producing labile proton exchanges too quickly with the solvent to produce any appreciable contrast. Through a number of variable temperature experiments we demonstrate that under the conditions when the hydrogen bond network breaks and the high exchange returns back, the contrast drops quickly. The well-known analgesic drug paracetamol shows 12% contrast at a concentration of 15 mM at physiological conditions. With the proven safety track-record for human consumption and appreciable physiological contrast, paracetamol shows promise as a diaCEST agent for in vivo studies.
Collapse
Affiliation(s)
- Subhayan Chakraborty
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), HBNI Bhubaneswar 752050 Odisha India
| | - S Peruncheralathan
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), HBNI Bhubaneswar 752050 Odisha India
| | - Arindam Ghosh
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), HBNI Bhubaneswar 752050 Odisha India
| |
Collapse
|
22
|
Longo DL, Irrera P, Consolino L, Sun PZ, McMahon MT. Renal pH Imaging Using Chemical Exchange Saturation Transfer (CEST) MRI: Basic Concept. Methods Mol Biol 2021; 2216:241-256. [PMID: 33476004 DOI: 10.1007/978-1-0716-0978-1_14] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
Abstract
Magnetic Resonance Imaging (MRI) has been actively explored in the last several decades for assessing renal function by providing several physiological information, including glomerular filtration rate, renal plasma flow, tissue oxygenation and water diffusion. Within MRI, the developing field of chemical exchange saturation transfer (CEST) has potential to provide further functional information for diagnosing kidney diseases. Both endogenous produced molecules as well as exogenously administered CEST agents have been exploited for providing functional information related to kidney diseases in preclinical studies. In particular, CEST MRI has been exploited for assessing the acid-base homeostasis in the kidney and for monitoring pH changes in several disease models. This review summarizes several CEST MRI procedures for assessing kidney functionality and pH, for monitoring renal pH changes in different kidney injury models and for evaluating renal allograft rejection.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This introduction chapter is complemented by two separate chapters describing the experimental procedure and data analysis.
Collapse
Affiliation(s)
- Dario Livio Longo
- Institute of Biostructures and Bioimaging (IBB), Italian National Research Council (CNR), Torino, Italy.
| | - Pietro Irrera
- University of Campania "Luigi Vanvitelli", Napoli, Italy
| | - Lorena Consolino
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Phillip Zhe Sun
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, USA
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Michael T McMahon
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
- Division of MR Research, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| |
Collapse
|
23
|
Liu G, van Zijl PC. CEST (Chemical Exchange Saturation Transfer) MR Molecular Imaging. Mol Imaging 2021. [DOI: 10.1016/b978-0-12-816386-3.00012-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
|
24
|
Chakraborty S, Das M, Srinivasan A, Ghosh A. Tetrakis-( N-methyl-4-pyridinium)-porphyrin as a diamagnetic chemical exchange saturation transfer (diaCEST) MRI contrast agent. NEW J CHEM 2021. [DOI: 10.1039/d0nj04869k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Easily synthesizable tetrakis-(N-methyl-4-pyridinium)-porphyrin as a diaCEST agent that shows nearly pH independent good contrast in a wide range of pH.
Collapse
Affiliation(s)
- Subhayan Chakraborty
- School of Chemical Sciences
- National Institute of Science Education and Research (NISER)
- HBNI
- Bhubaneswar 752050
- India
| | - Mainak Das
- School of Chemical Sciences
- National Institute of Science Education and Research (NISER)
- HBNI
- Bhubaneswar 752050
- India
| | - A. Srinivasan
- School of Chemical Sciences
- National Institute of Science Education and Research (NISER)
- HBNI
- Bhubaneswar 752050
- India
| | - Arindam Ghosh
- School of Chemical Sciences
- National Institute of Science Education and Research (NISER)
- HBNI
- Bhubaneswar 752050
- India
| |
Collapse
|
25
|
Repurposing Clinical Agents for Chemical Exchange Saturation Transfer Magnetic Resonance Imaging: Current Status and Future Perspectives. Pharmaceuticals (Basel) 2020; 14:ph14010011. [PMID: 33374213 PMCID: PMC7824058 DOI: 10.3390/ph14010011] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 12/19/2020] [Accepted: 12/21/2020] [Indexed: 12/24/2022] Open
Abstract
Molecular imaging is becoming an indispensable tool to pursue precision medicine. However, quickly translating newly developed magnetic resonance imaging (MRI) agents into clinical use remains a formidable challenge. Recently, Chemical Exchange Saturation Transfer (CEST) MRI is emerging as an attractive approach with the capability of directly using low concentration, exchangeable protons-containing agents for generating quantitative MRI contrast. The ability to utilize diamagnetic compounds has been extensively exploited to detect many clinical compounds, such as FDA approved drugs, X-ray/CT contrast agents, nutrients, supplements, and biopolymers. The ability to directly off-label use clinical compounds permits CEST MRI to be rapidly translated to clinical settings. In this review, the current status of CEST MRI based on clinically available compounds will be briefly introduced. The advancements and limitations of these studies are reviewed in the context of their pre-clinical or clinical applications. Finally, future directions will be briefly discussed.
Collapse
|
26
|
Cai X, Zhang J, Lu J, Yi L, Han Z, Zhang S, Yang X, Liu G. N-Aryl Amides as Chemical Exchange Saturation Transfer Magnetic Resonance Imaging Contrast Agents. Chemistry 2020; 26:11705-11709. [PMID: 32639618 PMCID: PMC10186200 DOI: 10.1002/chem.202002415] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/28/2020] [Indexed: 12/22/2022]
Abstract
Chemical exchange saturation transfer (CEST) MRI has recently emerged as a versatile molecular imaging approach in which diamagnetic compounds can be utilized to generate an MRI signal. To expand the scope of CEST MRI applications, herein, we systematically investigated the CEST properties of N-aryl amides with different N-aromatic substitution, revealing their chemical shifts (4.6-5.8 ppm) and exchange rates (up to thousands s-1 ) are favorable to be used as CEST agents as compared to alkyl amides. As the first proof-of-concept study, we used CEST MRI to detect the enzymatic metabolism of the drug acebutolol directly by its intrinsic CEST signal without any chemical labeling. Our study implies that N-aryl amides may enable the label-free CEST MRI detection of the metabolism of many N-aryl amide-containing drugs and a variety of enzymes that act on N-aryl amides, greatly expanding the scope of CEST MR molecular imaging.
Collapse
Affiliation(s)
- Xuekang Cai
- Department of Nuclear Medicine, Peking University First Hospital, 100034, Beijing, P. R. China.,State Key Laboratory of Organic-Inorganic Composites and Beijing Key Lab of Bioprocess, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, 100029, Beijing, P. R. China.,Institute of Medical Technology, Peking University, 100871, Beijing, P. R. China
| | - Jia Zhang
- Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, 21205, USA
| | - Jiaqi Lu
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, 21218, USA
| | - Long Yi
- State Key Laboratory of Organic-Inorganic Composites and Beijing Key Lab of Bioprocess, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, 100029, Beijing, P. R. China.,Institute of Medical Technology, Peking University, 100871, Beijing, P. R. China
| | - Zheng Han
- Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, 21205, USA
| | - Shuixing Zhang
- Department of Radiology, The First Affiliated Hospital of Jinan University, 510632, Guangzhou, Guandong, P. R. China
| | - Xing Yang
- Department of Nuclear Medicine, Peking University First Hospital, 100034, Beijing, P. R. China.,Institute of Medical Technology, Peking University, 100871, Beijing, P. R. China
| | - Guanshu Liu
- Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, 21205, USA
| |
Collapse
|
27
|
|
28
|
Pavuluri K, Rosenberg JT, Helsper S, Bo S, McMahon MT. Amplified detection of phosphocreatine and creatine after supplementation using CEST MRI at high and ultrahigh magnetic fields. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 313:106703. [PMID: 32179431 PMCID: PMC7197212 DOI: 10.1016/j.jmr.2020.106703] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 02/18/2020] [Accepted: 02/22/2020] [Indexed: 05/02/2023]
Abstract
Creatine is an important metabolite involved in muscle contraction. Administration of exogenous creatine (Cr) or phosphocreatine (PCr) has been used for improving exercise performance and protecting the heart during surgery including during valve replacements, coronary artery bypass grafting and repair of congenital heart defects. In this work we investigate whether it is possible to use chemical exchange saturation transfer (CEST) MRI to monitor uptake and clearance of exogenous creatine and phosphocreatine following supplementation. We were furthermore interested in determining the limiting conditions for distinguishing between creatine (1.9 ppm) and phosphocreatine (2.6 ppm) signals at ultra-high fields (21 T) and determine their concentrations could be reliably obtained using Bloch equation fits of the experimental CEST spectra. We have tested these items by performing CEST MRI of hind limb muscle and kidneys at 11.7 T and 21.1 T both before and after intravenous administration of PCr. We observed up to 4% increase in contrast in the kidneys at 2.6 ppm which peaked ~30 min after administration and a relative ratio of 1.3 in PCr:Cr signal. Overall, these results demonstrate the feasibility of independent monitoring of PCr and Cr concentration changes using CEST MRI.
Collapse
Affiliation(s)
- KowsalyaDevi Pavuluri
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, MD 21205, USA
| | - Jens T Rosenberg
- The National High Magnetic Field Laboratory, CIMAR, Florida State University, Tallahassee, FL, USA
| | - Shannon Helsper
- The National High Magnetic Field Laboratory, CIMAR, Florida State University, Tallahassee, FL, USA; Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Tallahassee, FL, USA
| | - Shaowei Bo
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, MD 21205, USA
| | - Michael T McMahon
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, MD 21205, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 N. Broadway Ave., Baltimore, MD 21205, USA.
| |
Collapse
|
29
|
Mathis CL, Saouma CT. Protic media enhanced protodeboronation for a potential H2O2-sensitive ligand system. Polyhedron 2020. [DOI: 10.1016/j.poly.2020.114377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
30
|
Yuan Y, Zhang J, Qi X, Li S, Liu G, Siddhanta S, Barman I, Song X, McMahon MT, Bulte JWM. Furin-mediated intracellular self-assembly of olsalazine nanoparticles for enhanced magnetic resonance imaging and tumour therapy. NATURE MATERIALS 2019; 18:1376-1383. [PMID: 31636420 PMCID: PMC6872935 DOI: 10.1038/s41563-019-0503-4] [Citation(s) in RCA: 143] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 09/10/2019] [Indexed: 05/15/2023]
Abstract
Among the strategies used for enhancement of tumour retention of imaging agents or anticancer drugs is the rational design of probes that undergo a tumour-specific enzymatic reaction preventing them from being pumped out of the cell. Here, the anticancer agent olsalazine (Olsa) was conjugated to the cell-penetrating peptide RVRR. Taking advantage of a biologically compatible condensation reaction, single Olsa-RVRR molecules were self-assembled into large intracellular nanoparticles by the tumour-associated enzyme furin. Both Olsa-RVRR and Olsa nanoparticles were readily detected with chemical exchange saturation transfer magnetic resonance imaging by virtue of exchangeable Olsa hydroxyl protons. In vivo studies using HCT116 and LoVo murine xenografts showed that the OlsaCEST signal and anti-tumour therapeutic effect were 6.5- and 5.2-fold increased, respectively, compared to Olsa without RVRR, with an excellent 'theranostic correlation' (R2 = 0.97) between the imaging signal and therapeutic response (normalized tumour size). This furin-targeted, magnetic resonance imaging-detectable platform has potential for imaging tumour aggressiveness, drug accumulation and therapeutic response.
Collapse
Affiliation(s)
- Yue Yuan
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jia Zhang
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Xiaoliang Qi
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Shuoguo Li
- Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Guanshu Liu
- The Russell H. Morgan Department of Radiology and Radiological Science, 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
| | - Soumik Siddhanta
- Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, MD, USA
| | - Ishan Barman
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, MD, USA
- Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Xiaolei Song
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Michael T McMahon
- The Russell H. Morgan Department of Radiology and Radiological Science, 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
| | - Jeff W M Bulte
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, 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.
- Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Department of Chemical & Biomolecular Engineering, The Johns Hopkins University, Baltimore, MD, USA.
| |
Collapse
|
31
|
Sun PZ. Development of intravoxel inhomogeneity correction for chemical exchange saturation transfer spectral imaging: a high-resolution field map-based deconvolution algorithm for magnetic field inhomogeneity correction. Magn Reson Med 2019; 83:1348-1355. [PMID: 31628765 DOI: 10.1002/mrm.28015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 09/04/2019] [Accepted: 09/05/2019] [Indexed: 12/12/2022]
Abstract
PURPOSE CEST MRI is sensitive to dilute proteins/peptides and microenvironmental properties yet susceptible to magnetic field inhomogeneity. We aimed to develop a high-resolution field map-based CEST intravoxel inhomogeneity correction (CIVIC) algorithm for CEST Z-spectral imaging. METHODS The proposed CIVIC approach treats the intravoxel inhomogeneity as a point spread function and applies the deconvolution algorithm to reconstruct the original Z-spectrum. We simulated the effect of B0 field inhomogeneity on CEST measurement and tested the efficacy of the proposed CIVIC algorithm. We also performed CEST MRI on a dual-pH Creatine-gel phantom under varied field homogeneity conditions and compared the CEST MRI contrast-to-noise ratio from the raw Z-spectrum, water saturation shift referencing, and the proposed CIVIC methods. RESULTS The numerical simulation showed that the CIVIC algorithm remains effective even in the case of symmetric field dispersion with a 0 mean shift. The experimental results confirmed that the proposed CIVIC method substantially improves the CEST MRI contrast-to-noise ratio under different field homogeneity conditions. CONCLUSION Our study established a new intravoxel B0 inhomogeneity correction algorithm, promising to facilitate CEST spectral imaging in challenging experimental conditions.
Collapse
Affiliation(s)
- Phillip Zhe Sun
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia.,Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Georgia
| |
Collapse
|
32
|
Goldenberg JM, Pagel MD. Assessments of tumor metabolism with CEST MRI. NMR IN BIOMEDICINE 2019; 32:e3943. [PMID: 29938857 PMCID: PMC7377947 DOI: 10.1002/nbm.3943] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 04/13/2018] [Accepted: 04/18/2018] [Indexed: 05/06/2023]
Abstract
Chemical exchange saturation transfer (CEST) is a relatively new contrast mechanism for MRI. CEST MRI exploits a specific MR frequency (chemical shift) of a molecule while generating an image with good spatial resolution using standard MRI techniques, combining the specificity of MRS with the spatial resolution of MRI. Many CEST MRI acquisition methods have been developed to improve analyses of tumor metabolism. GluCEST, CrCEST, and LATEST can map glutamate, creatine, and lactate, which are important metabolites involved in tumor metabolism. GlucoCEST MRI tracks the pharmacokinetics of glucose transport and cell internalization within tumors. CatalyCEST MRI detects enzyme catalysis that changes a substrate CEST agent. AcidoCEST MRI measures extracellular pH of the tumor microenvironment by exploiting a ratio of two pH-dependent CEST signals. This review describes each technique, the technical issues involved with CEST MRI and each specific technique, and the merits and challenges associated with applying each CEST MRI technique to study tumor metabolism.
Collapse
Affiliation(s)
- Joshua M. Goldenberg
- Department of Pharmaceutical Sciences, The University of Arizona, Tucson, AZ, USA
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Mark D. Pagel
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| |
Collapse
|
33
|
Zhang J, Yuan Y, Han Z, Li Y, van Zijl PCM, Yang X, Bulte JWM, Liu G. Detecting acid phosphatase enzymatic activity with phenol as a chemical exchange saturation transfer magnetic resonance imaging contrast agent (PhenolCEST MRI). Biosens Bioelectron 2019; 141:111442. [PMID: 31252256 PMCID: PMC6717000 DOI: 10.1016/j.bios.2019.111442] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 06/10/2019] [Accepted: 06/14/2019] [Indexed: 12/13/2022]
Abstract
Phenol contains an exchangeable hydroxyl proton resonant at 4.8 ppm from the resonance frequency of water in the 1H nuclear magnetic resonance (1H NMR) spectrum, enabling itself to be detected at sub-mM concentration by either chemical exchange saturation transfer magnetic resonance imaging (CEST MRI) or exchange-based T2 relaxation enhancement (T2ex) effect under acidic and basic conditions, respectively. We recently investigated the T2ex effects of phenol and its derivatives, but the CEST characteristics of phenols are unknown in detail, and no study on using the natural CEST MRI effects of phenol for detecting enzymatic activity has been conducted. Herein, on the basis of the inherent CEST MR property of phenol, namely phenolCEST, we developed the first MRI approach to detect acid phosphatase (AcP) enzymatic activity. Upon the activity of AcP at pH = 5.0, non-CEST-detectable enzyme substrate phenyl phosphate was converted to CEST-detectable phenol, providing a simple way to quantify AcP activity directly without the need for a second signalling probe. We showed the application of this phenolCEST biosensor for measuring AcP activity in both enzyme solutions and cell lysates of prostate cells. This work opens a door for the utilization of phenolCEST MRI technique in sensor design and development.
Collapse
Affiliation(s)
- Jia Zhang
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Yue Yuan
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Zheng Han
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Yuguo Li
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Peter C M van Zijl
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Xing Yang
- Department of Nuclear Medicine, Peking University First Hospital, Beijing, China
| | - Jeff W M Bulte
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Guanshu Liu
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States.
| |
Collapse
|
34
|
Zhang X, Yuan Y, Li S, Zeng Q, Guo Q, Liu N, Yang M, Yang Y, Liu M, McMahon MT, Zhou X. Free-base porphyrins as CEST MRI contrast agents with highly upfield shifted labile protons. Magn Reson Med 2019; 82:577-585. [PMID: 30968442 PMCID: PMC7294594 DOI: 10.1002/mrm.27753] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 02/26/2019] [Accepted: 03/06/2019] [Indexed: 12/29/2022]
Abstract
PURPOSE CEST has become a preeminent technology for the rapid detection and grading of tumors, securing its widespread use in both laboratory and clinical research. However, many existing CEST MRI agents exhibit a sensitivity limitation due to small chemical shifts between their exchangeable protons and water. We propose a new group of CEST MRI agents, free-base porphyrins and chlorin, with large exchangeable proton chemical shifts from water for enhanced detection. METHODS To test these newly identified CEST agents, we acquired a series of Z-spectra at multiple pH values and saturation field strengths to determine their CEST properties. The data were analyzed using the quantifying exchange using saturation power method to quantify exchange rates. After identifying several promising candidates, a porphyrin solution was injected into tumor-bearing mice, and MR images were acquired to assess detection feasibility in vivo. RESULTS Based on the Z-spectra, the inner nitrogen protons in free-base porphyrins and chlorin resonate from -8 to -13.5 ppm from water, far shifted from the majority of endogenous metabolites (0-4 ppm) and Nuclear Overhauser enhancements (-1 to -3.5 ppm) and far removed from the salicylates, imidazoles, and anthranillates (5-12 ppm). The exchange rates are sufficiently slow to intermediate (500-9000 s-1 ) to allow robust detection and were sensitive to substituents on the porphyrin ring. CONCLUSION These results highlight the capabilities of free-base porphyrins and chlorin as highly upfield CEST MRI agents and provide a new scaffold that can be integrated into a variety of diagnostic or theranostic agents for biomedical applications.
Collapse
Affiliation(s)
- Xiaoxiao Zhang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Collaborative Innovation Center of Chemistry for Life Sciences, Wuhan Institute of Physics and Mathematics-Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan, People’s Republic of China
| | - Yaping Yuan
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Collaborative Innovation Center of Chemistry for Life Sciences, Wuhan Institute of Physics and Mathematics-Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Sha Li
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Collaborative Innovation Center of Chemistry for Life Sciences, Wuhan Institute of Physics and Mathematics-Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Qingbin Zeng
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Collaborative Innovation Center of Chemistry for Life Sciences, Wuhan Institute of Physics and Mathematics-Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Qianni Guo
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Collaborative Innovation Center of Chemistry for Life Sciences, Wuhan Institute of Physics and Mathematics-Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Na Liu
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Collaborative Innovation Center of Chemistry for Life Sciences, Wuhan Institute of Physics and Mathematics-Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Minghui Yang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Collaborative Innovation Center of Chemistry for Life Sciences, Wuhan Institute of Physics and Mathematics-Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Yunhuang Yang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Collaborative Innovation Center of Chemistry for Life Sciences, Wuhan Institute of Physics and Mathematics-Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Maili Liu
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Collaborative Innovation Center of Chemistry for Life Sciences, Wuhan Institute of Physics and Mathematics-Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Michael T. McMahon
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | - Xin Zhou
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Collaborative Innovation Center of Chemistry for Life Sciences, Wuhan Institute of Physics and Mathematics-Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing, People’s Republic of China
| |
Collapse
|
35
|
Abstract
Many elegant inorganic designs have been developed to aid medical imaging. We know better now how to improve imaging due to the enormous efforts made by scientists in probe design and other fundamental sciences, including inorganic chemistry, physiochemistry, analytical chemistry, and biomedical engineering. However, despite several years being invested in the development of diagnostic probes, only a few examples have shown applicability in MRI in vivo. In this short review, we aim to show the reader the latest advances in the application of inorganic agents in preclinical MRI.
Collapse
|
36
|
Han Z, Liu G. Sugar-based biopolymers as novel imaging agents for molecular magnetic resonance imaging. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2019; 11:e1551. [PMID: 30666829 DOI: 10.1002/wnan.1551] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 11/21/2018] [Accepted: 12/10/2018] [Indexed: 12/11/2022]
Abstract
Sugar-based biopolymers have been recognized as attractive materials to develop macromolecule- and nanoparticle-based cancer imaging and therapy. However, traditional biopolymer-based imaging approaches rely on the use of synthetic or isotopic labeling, and because of it, clinical translation often is hindered. Recently, a novel magnetic resonance imaging (MRI) technology, chemical exchange saturation transfer (CEST), has emerged, which allows the exploitation of sugar-based biopolymers as MRI agents by their hydroxyl protons-rich nature. In the study, we reviewed recent studies on the topic of CEST MRI detection of sugar-based biopolymers. The CEST MRI property of each biopolymer was briefly introduced, followed by the pre-clinical and clinical applications. The findings of these preliminary studies imply the enormous potential of CEST detectable sugar-based biopolymers in developing highly sensitive and translatable molecular imaging agents and constructing image-guided biopolymer-based drug delivery systems. This article is categorized under: Diagnostic Tools > in vivo Nanodiagnostics and Imaging Therapeutic Approaches and Drug Discovery > Emerging Technologies.
Collapse
Affiliation(s)
- Zheng Han
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Guanshu Liu
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins School of Medicine, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| |
Collapse
|
37
|
Sinharay S, Randtke EA, Howison CM, Ignatenko NA, Pagel MD. Detection of Enzyme Activity and Inhibition during Studies in Solution, In Vitro and In Vivo with CatalyCEST MRI. Mol Imaging Biol 2019; 20:240-248. [PMID: 28726131 DOI: 10.1007/s11307-017-1092-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
PURPOSE The detection of enzyme activities and evaluation of enzyme inhibitors have been challenging with magnetic resonance imaging (MRI). To address this need, we have developed a diamagnetic, nonmetallic contrast agent and a protocol known as catalyCEST MRI that uses chemical exchange saturation transfer (CEST) to detect enzyme activity as well as enzyme inhibition. PROCEDURES We synthesized a diamagnetic MRI contrast agent that has enzyme responsive and enzyme unresponsive CEST signals. We tested the ability of this agent to detect the activity of kallikrein 6 (KLK6) in biochemical solutions, in vitro and in vivo, with and without a KLK6 inhibitor. RESULTS The agent detected KLK6 activity in solution and also detected KLK6 inhibition by antithrombin III. KLK6 activity was detected during in vitro studies with HCT116 colon cancer cells, relative to the detection of almost no activity in a KLK6-knockdown HCT116 cell line and HCT116 cells treated with antithrombin III inhibitor. Finally, strong enzyme activity was detected within an in vivo HCT116 tumor model, while lower enzyme activity was detected in a KLK6 knockdown tumor model and in the HCT116 tumor model treated with antithrombin III inhibitor. In all cases, comparisons of the enzyme responsive and enzyme unresponsive CEST signals were critical for the detection of enzyme activity. CONCLUSIONS This study has established that catalyCEST MRI with an exogenous diaCEST agent can evaluate enzyme activity and inhibition in solution, in vitro and in vivo.
Collapse
Affiliation(s)
- Sanhita Sinharay
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
| | - Edward A Randtke
- Department of Medical Imaging, University of Arizona, 1515 N. Campbell Avenue, Tucson, AZ, 84724-5024, USA
| | - Christine M Howison
- Department of Medical Imaging, University of Arizona, 1515 N. Campbell Avenue, Tucson, AZ, 84724-5024, USA
| | - Natalia A Ignatenko
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, USA.,University of Arizona Cancer Center, 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, 1515 N. Campbell Avenue, Tucson, AZ, 84724-5024, USA. .,University of Arizona Cancer Center, University of Arizona, Tucson, AZ, USA. .,Department of Cancer Systems Imaging, MD Anderson Cancer Center, 1881 East Road, Houston, TX, 77054, USA.
| |
Collapse
|
38
|
Zhang J, Han Z, Lu J, Li Y, Liao X, van Zijl PC, Yang X, Liu G. Triazoles as T 2 -Exchange Magnetic Resonance Imaging Contrast Agents for the Detection of Nitrilase Activity. Chemistry 2018; 24:15013-15018. [PMID: 29989227 DOI: 10.1002/chem.201802663] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Indexed: 02/04/2023]
Abstract
We characterized the T2 -exchange (T2ex ) magnetic resonance imaging (MRI) contrast of azole protons that have large chemical shifts from the water proton resonance as a function of pH, temperature, and chemical modification. Our results showed that 1,2,4-triazoles could be tuned into excellent diamagnetic T2ex contrast agents, with an optimal exchange-based relaxivity r2ex of 0.10 s-1 mm-1 at physiological pH and B0 =9.4 T. A fit of r2ex data to the Swift-Connick equation indicated that imino proton exchange of triazoles is dominated by a base-catalyzed process at higher pH values and an acid-catalyzed process at lower pH. The magnitude of r2ex was also found to be heavily dependent on chemical modifications, that is, enhanced by electron-donating groups, such as amines and methyls, or by intramolecular hydrogen bonding between the imino proton and the carboxyl, and weakened by electron-withdrawing groups like bromo, cyano, and nitro. In light of these findings, we applied T2ex MRI to assess the activity of nitrilase, an enzyme catalyzing the hydrolysis of 1,2,4-triazole-3-carbonitrile to 1,2,4-triazole-3-carboxylic acid, resulting in the enhancement of R2ex . Our findings suggest that 1,2,4-triazoles have potential to provide sensitive and tunable diagnostic probes for MRI.
Collapse
Affiliation(s)
- Jia Zhang
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Zheng Han
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jiaqi Lu
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Yuguo Li
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Xuhe Liao
- Department of Nuclear Medicine, Peking University First Hospital, Beijing, P. R. China
| | - Peter C van Zijl
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, 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
| | - Xing Yang
- Department of Nuclear Medicine, Peking University First Hospital, Beijing, P. R. China
| | - Guanshu Liu
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, 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
| |
Collapse
|
39
|
Gutjahr FT, Munz E, Jakob PM. Positive chemical exchange contrast in MRI using Refocused Acquisition of Chemical Exchange Transferred Excitations (RACETE). Z Med Phys 2018; 29:184-191. [PMID: 29907396 DOI: 10.1016/j.zemedi.2018.05.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 05/18/2018] [Accepted: 05/22/2018] [Indexed: 11/19/2022]
Abstract
PURPOSE A new chemical exchange MRI method is proposed which allows for direct detection of exchanging solute protons with concurrent water background suppression. METHODS The proposed method, RACETE (Refocused Acquisition of Chemical Exchange Transferred Excitations), is based on a stimulated-echo-technique, where the first two excitation pulses are replaced by a train of N solute-selective excitation-transfer modules. This excitation cycle is then followed by a stimulated echo acquisition via selective refocusing of exchanged solute protons now present in the solvent pool. RESULTS The obtained magnitude and phase phantom images demonstrate that with only one RACETE-imaging experiment two different chemical exchange active substances with mMol-concentrations can be detected and distinguished simultaneously. CONCLUSION The proposed RACETE-approach allows for true positive chemical exchange contrast imaging with the proven ability to exploit magnitude as well as phase image data.
Collapse
Affiliation(s)
- Fabian Tobias Gutjahr
- Universität Würzburg, Lehrstuhl für Experimentelle Physik 5, Am Hubland, 97074 Würzburg, Germany.
| | - Eberhard Munz
- Universität Würzburg, Lehrstuhl für Experimentelle Physik 5, Am Hubland, 97074 Würzburg, Germany; Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, 06466 Gatersleben, Germany
| | - Peter Michael Jakob
- Universität Würzburg, Lehrstuhl für Experimentelle Physik 5, Am Hubland, 97074 Würzburg, Germany
| |
Collapse
|
40
|
Banerjee SR, Song X, Yang X, Minn I, Lisok A, Chen Y, Bui A, Chatterjee S, Chen J, van Zijl PCM, McMahon MT, Pomper MG. Salicylic Acid-Based Polymeric Contrast Agents for Molecular Magnetic Resonance Imaging of Prostate Cancer. Chemistry 2018; 24:7235-7242. [PMID: 29508450 PMCID: PMC5980787 DOI: 10.1002/chem.201800882] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Indexed: 01/31/2023]
Abstract
Chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) is an innovative molecular imaging technique in which contrast agents are labeled by saturating their exchangeable proton spins by radio-frequency irradiation. Salicylic acid and its analogues are a promising class of highly sensitive, diamagnetic CEST agents. Herein, polymeric agents grafted with salicylic acid moieties and a known high-affinity ligand targeting prostate-specific membrane antigen in approximately 10:1 molar ratio were synthesized to provide sufficient MRI sensitivity and receptor specificity. The proton-exchange properties of the contrast agent in solution and in an experimental murine model are reported to demonstrate the feasibility of receptor-targeted CEST MRI of prostate cancer. Furthermore, the CEST imaging data were validated with an 111 In-labeled analogue of the agent by in vivo single photon emission computed tomographic imaging and tissue biodistribution studies.
Collapse
Affiliation(s)
- Sangeeta Ray Banerjee
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA, 21287
| | - Xiaolei Song
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA, 21287
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Xing Yang
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA, 21287
| | - Il Minn
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA, 21287
| | - Ala Lisok
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA, 21287
| | - Yanrong Chen
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Albert Bui
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA, 21287
| | - Samit Chatterjee
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA, 21287
| | - Jian Chen
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA, 21287
| | - Peter C. M. van Zijl
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA, 21287
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Michael T. McMahon
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA, 21287
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Martin G. Pomper
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA, 21287
| |
Collapse
|
41
|
Cohen O, Huang S, McMahon MT, Rosen MS, Farrar CT. Rapid and quantitative chemical exchange saturation transfer (CEST) imaging with magnetic resonance fingerprinting (MRF). Magn Reson Med 2018; 80:2449-2463. [PMID: 29756286 DOI: 10.1002/mrm.27221] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 03/19/2018] [Accepted: 03/25/2018] [Indexed: 01/19/2023]
Abstract
PURPOSE To develop a fast magnetic resonance fingerprinting (MRF) method for quantitative chemical exchange saturation transfer (CEST) imaging. METHODS We implemented a CEST-MRF method to quantify the chemical exchange rate and volume fraction of the Nα -amine protons of L-arginine (L-Arg) phantoms and the amide and semi-solid exchangeable protons of in vivo rat brain tissue. L-Arg phantoms were made with different concentrations (25-100 mM) and pH (pH 4-6). The MRF acquisition schedule varied the saturation power randomly for 30 iterations (phantom: 0-6 μT; in vivo: 0-4 μT) with a total acquisition time of ≤2 min. The signal trajectories were pattern-matched to a large dictionary of signal trajectories simulated using the Bloch-McConnell equations for different combinations of exchange rate, exchangeable proton volume fraction, and water T1 and T2 relaxation times. RESULTS The chemical exchange rates of the Nα -amine protons of L-Arg were significantly (P < 0.0001) correlated with the rates measured with the quantitation of exchange using saturation power method. Similarly, the L-Arg concentrations determined using MRF were significantly (P < 0.0001) correlated with the known concentrations. The pH dependence of the exchange rate was well fit (R2 = 0.9186) by a base catalyzed exchange model. The amide proton exchange rate measured in rat brain cortex (34.8 ± 11.7 Hz) was in good agreement with that measured previously with the water exchange spectroscopy method (28.6 ± 7.4 Hz). The semi-solid proton volume fraction was elevated in white (12.2 ± 1.7%) compared to gray (8.1 ± 1.1%) matter brain regions in agreement with previous magnetization transfer studies. CONCLUSION CEST-MRF provides a method for fast, quantitative CEST imaging.
Collapse
Affiliation(s)
- Ouri Cohen
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts
| | - Shuning Huang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts
| | - Michael T McMahon
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland.,Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Matthew S Rosen
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts.,Department of Physics, Harvard University, Cambridge, Massachusetts
| | - Christian T Farrar
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts
| |
Collapse
|
42
|
McMahon MT, Bulte JWM. Two decades of dendrimers as versatile MRI agents: a tale with and without metals. WILEY INTERDISCIPLINARY REVIEWS. NANOMEDICINE AND NANOBIOTECHNOLOGY 2018; 10:e1496. [PMID: 28895298 PMCID: PMC5989322 DOI: 10.1002/wnan.1496] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/25/2017] [Accepted: 08/02/2017] [Indexed: 12/24/2022]
Abstract
Dendrimers or dendritic polymers are a class of compounds with great potential for nanomedical use. Some of their properties, including their rigidity, low polydispersity and the ease with which their surfaces can be modified make them particularly well suited for use as MRI diagnostic or theranostic agents. For the past 20 years, researchers have recognized this potential and refined dendrimer formulations to optimize these nanocarriers for a host of MRI applications, including blood pool imaging agents, lymph node imaging agents, tumor-targeted theranostic agents and cell tracking agents. This review summarizes the various types of dendrimers according to the type of MR contrast they can provide. This includes the metallic T1 , T2 and paraCEST imaging agents, and the non-metallic diaCEST and fluorinated (19 F) heteronuclear imaging agents. This article is categorized under: Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Implantable Materials and Surgical Technologies > Nanomaterials and Implants.
Collapse
Affiliation(s)
- Michael T. McMahon
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, 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
| | - Jeff W. M. Bulte
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, 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
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Chemical & Biomolecular Engineering, The Johns Hopkins University Whiting School of Engineering, Baltimore, MD, USA
| |
Collapse
|
43
|
Zhang J, Li Y, Slania S, Yadav NN, Liu J, Wang R, Zhang J, Pomper MG, van Zijl PC, Yang X, Liu G. Phenols as Diamagnetic T 2 -Exchange Magnetic Resonance Imaging Contrast Agents. Chemistry 2018; 24:1259-1263. [PMID: 29266443 PMCID: PMC5786484 DOI: 10.1002/chem.201705772] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Indexed: 01/03/2023]
Abstract
Although T2 -exchange (T2ex ) NMR phenomena have been known for decades, there has been a resurgence of interest to develop T2ex MRI contrast agents. One indispensable advantage of T2ex MR agents is the possibility of using non-toxic and/or bio-compatible diamagnetic compounds with intermediate exchangeable protons. Herein a library of phenol-based compounds is screened and their T2ex contrast (exchange relaxivity, r2ex ) at 9.4 T determined. The T2ex contrast of phenol protons allows direct detection by MRI at a millimolar concentration level. The effect of chemical modification of the phenol on the T2ex MRI contrast through modulation of exchange rate and chemical shift was also studied and provides a guideline for use of endogenous and exogenous phenols for T2ex MRI contrast. As a proof-of-principle application, phenol T2ex contrast can be used to detect enzyme activity in a tyrosinase-catalyzed catechol oxidation reaction.
Collapse
Affiliation(s)
- Jia Zhang
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Yuguo Li
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Stephanie Slania
- Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, Maryland, USA
| | - Nirbhay N Yadav
- The Russell H. Morgan Department of Radiology, 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
| | - Jing Liu
- Graduate College, Southern Medical University, Guangzhou, Guangdong, P. R. China
| | - Rongfu Wang
- Department of Nuclear Medicine, Peking University First Hospital Beijing, P. R. China
| | - Jianhua Zhang
- Department of Nuclear Medicine, Peking University First Hospital Beijing, P. R. China
| | - Martin G Pomper
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Peter C van Zijl
- The Russell H. Morgan Department of Radiology, 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
| | - Xing Yang
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Nuclear Medicine, Peking University First Hospital Beijing, P. R. China
| | - Guanshu Liu
- The Russell H. Morgan Department of Radiology, 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
| |
Collapse
|
44
|
Systematic Evaluation of Amide Proton Chemical Exchange Saturation Transfer at 3 T: Effects of Protein Concentration, pH, and Acquisition Parameters. Invest Radiol 2017; 51:635-46. [PMID: 27272542 DOI: 10.1097/rli.0000000000000292] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVE The goal of this work was to systematically evaluate the reproducibility of amide proton transfer chemical exchange saturation transfer (APT-CEST) at 3 T and its signal dependence on pH, protein concentration, and acquisition parameters. An in vitro system based on bovine serum albumin (BSA) was used, and its limitations were tested by comparing it to in vivo measurements. The contribution of small endogenous metabolites on the APT-CEST signal at 3 T was also investigated. In addition, the reliability of different z-spectrum interpolations as well as the use of only a few frequency offset data points instead of a whole z-spectrum were tested. MATERIALS AND METHODS We created both a BSA phantom at different concentrations and pH values and a metabolite phantom with different small molecules. Chemical exchange saturation transfer data were acquired using a 2-dimensional fast spoiled gradient-echo sequence with pulsed CEST preparation at different saturation durations and power levels. Healthy volunteer measurements were taken for comparison. Z-spectra were interpolated using a 24th-order polynomial (Poly), an eighth-order Fourier series (Fourier), and a smoothing Spline (sSpline) algorithm. To evaluate reduced data sets, only 6 to 14 frequency offsets of the z-spectrum were used and interpolated via a cubic Spline. Region of interest (ROI) evaluations were used to investigate the reproducibility of amide magnetization transfer ratio asymmetry [MTRasym(3.5 ppm)] and to analyze the MTRasym and z-spectra. RESULTS Interscan standard deviations of MTRasym(3.5 ppm) were always below 0.3%. MTRasym(3.5 ppm) increased when the BSA concentrations increased and decreased when the pH increased. The amine MTRasym signal of small molecules was very small compared with BSA and was only detectable using short saturation times and higher power levels. The MTRasym(3.5 ppm) between BSA concentration steps and between nearly all pH steps was significantly different for all 3 fitting methods. The Fourier and sSpline methods showed no statistically significant differences; however, the results for the Poly method were significantly higher at some concentrations and pH values. Using only few frequency offsets resulted in less significant differences compared with fitting the complete z-spectrum. In general, MTRasym(3.5 ppm) of gray matter, white matter, and ventricle ROIs from volunteer scans increased with an increase in saturation power and partially decreased with an increase in saturation duration. Intra-ROI covariances of MTRasym(3.5 ppm) revealed the highest variations for Poly, whereas using reduced spectral data resulted in an increased signal variation. CONCLUSIONS Amide proton transfer-CEST imaging is a highly reproducible method in which absolute signal differences of approximately 0.5% are detectable in principle. For in vivo applications, Fourier or sSpline interpolations of z-spectra are preferable. Using reduced data sets delivers similar results but with increased variation and therefore decreased (pH/concentration) differentiation capability. Differentiation capability increases with increases in the saturation duration and power level. The results from the in vitro BSA system cannot be directly transferred to the in vivo situation due to different chemical environments resulting in, for example, higher asymmetric macromolecular cMT effects in vivo. Amine signals from small molecules are unlikely to contribute to APT-CEST at 3 T (except for creatine); however, signals can be enhanced by using short saturation times and higher power levels.
Collapse
|
45
|
Affiliation(s)
- KowsalyaDevi Pavuluri
- Russell H. Morgan Department of Radiology and Radiological Science; Johns Hopkins University School of Medicine; Baltimore, Maryland 21205 United States
| | - Michael T. McMahon
- Russell H. Morgan Department of Radiology and Radiological Science; 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
| |
Collapse
|
46
|
Jones KM, Pollard AC, Pagel MD. Clinical applications of chemical exchange saturation transfer (CEST) MRI. J Magn Reson Imaging 2017; 47:11-27. [PMID: 28792646 DOI: 10.1002/jmri.25838] [Citation(s) in RCA: 184] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Accepted: 05/30/2017] [Indexed: 02/06/2023] Open
Abstract
Chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) has been developed and employed in multiple clinical imaging research centers worldwide. Selective radiofrequency (RF) saturation pulses with standard 2D and 3D MRI acquisition schemes are now routinely performed, and CEST MRI can produce semiquantitative results using magnetization transfer ratio asymmetry (MTRasym ) analysis while accounting for B0 inhomogeneity. Faster clinical CEST MRI acquisition methods and more quantitative acquisition and analysis routines are under development. Endogenous biomolecules with amide, amine, and hydroxyl groups have been detected during clinical CEST MRI studies, and exogenous CEST agents have also been administered to patients. These CEST MRI tools show promise for contributing to assessments of cerebral ischemia, neurological disorders, lymphedema, osteoarthritis, muscle physiology, and solid tumors. This review summarizes the salient features of clinical CEST MRI protocols and critically evaluates the utility of CEST MRI for these clinical imaging applications. LEVEL OF EVIDENCE 5 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:11-27.
Collapse
Affiliation(s)
- Kyle M Jones
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona, USA
| | | | - Mark D Pagel
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona, USA.,Department of Chemistry, Rice University, Houston, Texas, USA.,Department of Cancer Systems Imaging, MD Anderson Cancer Center, Houston, Texas, USA
| |
Collapse
|
47
|
Zaiss M, Angelovski G, Demetriou E, McMahon MT, Golay X, Scheffler K. QUESP and QUEST revisited - fast and accurate quantitative CEST experiments. Magn Reson Med 2017; 79:1708-1721. [PMID: 28686796 DOI: 10.1002/mrm.26813] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 05/17/2017] [Accepted: 06/03/2017] [Indexed: 01/24/2023]
Abstract
PURPOSE Chemical exchange saturation transfer (CEST) NMR or MRI experiments allow detection of low concentrated molecules with enhanced sensitivity via their proton exchange with the abundant water pool. Be it endogenous metabolites or exogenous contrast agents, an exact quantification of the actual exchange rate is required to design optimal pulse sequences and/or specific sensitive agents. METHODS Refined analytical expressions allow deeper insight and improvement of accuracy for common quantification techniques. The accuracy of standard quantification methodologies, such as quantification of exchange rate using varying saturation power or varying saturation time, is improved especially for the case of nonequilibrium initial conditions and weak labeling conditions, meaning the saturation amplitude is smaller than the exchange rate (γB1 < k). RESULTS The improved analytical 'quantification of exchange rate using varying saturation power/time' (QUESP/QUEST) equations allow for more accurate exchange rate determination, and provide clear insights on the general principles to execute the experiments and to perform numerical evaluation. The proposed methodology was evaluated on the large-shift regime of paramagnetic chemical-exchange-saturation-transfer agents using simulated data and data of the paramagnetic Eu(III) complex of DOTA-tetraglycineamide. CONCLUSIONS The refined formulas yield improved exchange rate estimation. General convergence intervals of the methods that would apply for smaller shift agents are also discussed. Magn Reson Med 79:1708-1721, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Moritz Zaiss
- High Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Goran Angelovski
- MR Neuroimaging Agents, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Eleni Demetriou
- Brain Repair & Rehabilitation, Institute of Neurology, University College London, United Kingdom
| | - Michael T McMahon
- 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
| | - Xavier Golay
- Brain Repair & Rehabilitation, Institute of Neurology, University College London, United Kingdom
| | - Klaus Scheffler
- High Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Department of Biomedical Magnetic Resonance, Eberhard Karl's University of Tübingen and University Hospital, Tübingen, Germany
| |
Collapse
|
48
|
Sinharay S, Howison CM, Baker AF, Pagel MD. Detecting in vivo urokinase plasminogen activator activity with a catalyCEST MRI contrast agent. NMR IN BIOMEDICINE 2017; 30:10.1002/nbm.3721. [PMID: 28370884 PMCID: PMC5704996 DOI: 10.1002/nbm.3721] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Revised: 02/04/2017] [Accepted: 02/06/2017] [Indexed: 05/22/2023]
Abstract
Urokinase plasminogen activator (uPA) promotes tumor invasion and metastasis. The monitoring of uPA activity using molecular imaging may have prognostic value and be predictive for response to anti-cancer therapies. However, the detection of in vivo enzyme activity with molecular imaging remains a challenge. To address this problem, we designed a nonmetallic contrast agent, GR-4Am-SA, that can be detected with chemical exchange saturation transfer (CEST) MRI. This agent has a peptide that is cleaved by uPA, which causes a CEST signal at 5.0 ppm to decrease, and also has a salicylic acid moiety that can produce a CEST signal at 9.5 ppm, which is largely unresponsive to enzyme activity. The two CEST signals were used to determine a reaction coordinate, representing the extent of enzyme-catalyzed cleavage of the GR-4Am-SA agent during an experimental study. Initial biochemical studies showed that GR-4Am-SA could detect uPA activity in reducing conditions. Subsequently, we used our catalyCEST MRI protocol with the agent to detect the uPA catalysis of GR-4Am-SA in a flank xenograft model of Capan-2 pancreatic cancer. The results showed an average reaction coordinate of 80% ± 8%, which was strongly dependent on the CEST signal at 5.0 ppm. The relative independence of the reaction coordinate on the CEST signal at 9.5 ppm showed that the detection of enzyme activity was largely independent of the concentration of GR-4Am-SA within the tumor tissue. These results demonstrated the advantages of a single CEST agent with biomarker-responsive and unresponsive signals for reliably assessing enzyme activity during in vivo cancer studies.
Collapse
Affiliation(s)
- Sanhita Sinharay
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ
| | | | - Amanda F. Baker
- University of Arizona Cancer Center, University of Arizona, Tucson, AZ
| | - Mark D. Pagel
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ
- University of Arizona Cancer Center, University of Arizona, Tucson, AZ
- Department of Medical Imaging, University of Arizona, Tucson, AZ
- Corresponding Author: Mark D. Pagel, University of Arizona Cancer Center, 1515 N. Campbell Avenue, Tucson, AZ 85724-5024, Tel: (520)-404-7049, Fax: (520)-626-0395,
| |
Collapse
|
49
|
EXCI-CEST: Exploiting pharmaceutical excipients as MRI-CEST contrast agents for tumor imaging. Int J Pharm 2017; 525:275-281. [DOI: 10.1016/j.ijpharm.2017.04.040] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 04/11/2017] [Accepted: 04/18/2017] [Indexed: 12/22/2022]
|
50
|
van Zijl PCM, Lam WW, Xu J, Knutsson L, Stanisz GJ. Magnetization Transfer Contrast and Chemical Exchange Saturation Transfer MRI. Features and analysis of the field-dependent saturation spectrum. Neuroimage 2017; 168:222-241. [PMID: 28435103 DOI: 10.1016/j.neuroimage.2017.04.045] [Citation(s) in RCA: 206] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 04/18/2017] [Accepted: 04/19/2017] [Indexed: 11/30/2022] Open
Abstract
Magnetization Transfer Contrast (MTC) and Chemical Exchange Saturation Transfer (CEST) experiments measure the transfer of magnetization from molecular protons to the solvent water protons, an effect that becomes apparent as an MRI signal loss ("saturation"). This allows molecular information to be accessed with the enhanced sensitivity of MRI. In analogy to Magnetic Resonance Spectroscopy (MRS), these saturation data are presented as a function of the chemical shift of participating proton groups, e.g. OH, NH, NH2, which is called a Z-spectrum. In tissue, these Z-spectra contain the convolution of multiple saturation transfer effects, including nuclear Overhauser enhancements (NOEs) and chemical exchange contributions from protons in semi-solid and mobile macromolecules or tissue metabolites. As a consequence, their appearance depends on the magnetic field strength (B0) and pulse sequence parameters such as B1 strength, pulse shape and length, and interpulse delay, which presents a major problem for quantification and reproducibility of MTC and CEST effects. The use of higher B0 can bring several advantages. In addition to higher detection sensitivity (signal-to-noise ratio, SNR), both MTC and CEST studies benefit from longer water T1 allowing the saturation transferred to water to be retained longer. While MTC studies are non-specific at any field strength, CEST specificity is expected to increase at higher field because of a larger chemical shift dispersion of the resonances of interest (similar to MRS). In addition, shifting to a slower exchange regime at higher B0 facilitates improved detection of the guanidinium protons of creatine and the inherently broad resonances of the amine protons in glutamate and the hydroxyl protons in myoinositol, glycogen, and glucosaminoglycans. Finally, due to the higher mobility of the contributing protons in CEST versus MTC, many new pulse sequences can be designed to more specifically edit for CEST signals and to remove MTC contributions.
Collapse
Affiliation(s)
- Peter C M van Zijl
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, 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.
| | - Wilfred W Lam
- Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Jiadi Xu
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, 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
| | - Linda Knutsson
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - Greg J Stanisz
- Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada; Department of Neurosurgery and Pediatric Neurosurgery, Medical University of Lublin, Lublin, Poland.
| |
Collapse
|