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Zheng H, Harcum SW, Pei J, Xie W. Stochastic biological system-of-systems modelling for iPSC culture. Commun Biol 2024; 7:39. [PMID: 38191636 PMCID: PMC10774284 DOI: 10.1038/s42003-023-05653-w] [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: 07/29/2023] [Accepted: 11/30/2023] [Indexed: 01/10/2024] Open
Abstract
Large-scale manufacturing of induced pluripotent stem cells (iPSCs) is essential for cell therapies and regenerative medicines. Yet, iPSCs form large cell aggregates in suspension bioreactors, resulting in insufficient nutrient supply and extra metabolic waste build-up for the cells located at the core. Since subtle changes in micro-environment can lead to a heterogeneous cell population, a novel Biological System-of-Systems (Bio-SoS) framework is proposed to model cell-to-cell interactions, spatial and metabolic heterogeneity, and cell response to micro-environmental variation. Building on stochastic metabolic reaction network, aggregation kinetics, and reaction-diffusion mechanisms, the Bio-SoS model characterizes causal interdependencies at individual cell, aggregate, and cell population levels. It has a modular design that enables data integration and improves predictions for different monolayer and aggregate culture processes. In addition, a variance decomposition analysis is derived to quantify the impact of factors (i.e., aggregate size) on cell product health and quality heterogeneity.
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Affiliation(s)
- Hua Zheng
- Mechanical and Industrial Engineering, Northeastern University, Boston, MA, 02115, USA
| | | | - Jinxiang Pei
- Mechanical and Industrial Engineering, Northeastern University, Boston, MA, 02115, USA
| | - Wei Xie
- Mechanical and Industrial Engineering, Northeastern University, Boston, MA, 02115, USA.
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2
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Patel RJS, Harlan CJ, Fuentes DT, Bankson JA. A Simulation of the Effects of Diffusion on Hyperpolarized [1- 13C]-Pyruvate Signal Evolution. IEEE Trans Biomed Eng 2023; 70:2905-2913. [PMID: 37097803 PMCID: PMC10538435 DOI: 10.1109/tbme.2023.3269665] [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] [Indexed: 04/26/2023]
Abstract
OBJECTIVE Hyperpolarized [1-13C]-pyruvate magnetic resonance imaging is an emerging metabolic imaging method that offers unprecedented spatiotemporal resolution for monitoring tumor metabolism in vivo. To establish robust imaging biomarkers of metabolism, we must characterize phenomena that may modulate the apparent pyruvate-to-lactate conversion rate (kPL). Here, we investigate the potential effect of diffusion on pyruvate-to-lactate conversion, as failure to account for diffusion in pharmacokinetic analysis may obscure true intracellular chemical conversion rates. METHODS Changes in hyperpolarized pyruvate and lactate signal were calculated using a finite-difference time domain simulation of a two-dimensional tissue model. Signal evolution curves with intracellular kPL values from 0.02 to 1.00 s-1 were analyzed using spatially invariant one-compartment and two-compartment pharmacokinetic models. A second spatially variant simulation incorporating compartmental instantaneous mixing was fit with the same one-compartment model. RESULTS When fitting with the one-compartment model, apparent kPL underestimated intracellular kPL by approximately 50% at an intracellular kPL of 0.02 s-1. This underestimation increased for larger kPL values. However, fitting the instantaneous mixing curves showed that diffusion accounted for only a small part of this underestimation. Fitting with the two-compartment model yielded more accurate intracellular kPL values. SIGNIFICANCE This work suggests diffusion is not a significant rate-limiting factor in pyruvate-to-lactate conversion given that our model assumptions hold true. In higher order models, diffusion effects may be accounted for by a term characterizing metabolite transport. Pharmacokinetic models used to analyze hyperpolarized pyruvate signal evolution should focus on carefully selecting the analytical model for fitting rather than accounting for diffusion effects.
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3
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Idumah G, Somersalo E, Calvetti D. A spatially distributed model of brain metabolism highlights the role of diffusion in brain energy metabolism. J Theor Biol 2023; 572:111567. [PMID: 37393987 DOI: 10.1016/j.jtbi.2023.111567] [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: 10/26/2022] [Revised: 06/20/2023] [Accepted: 06/22/2023] [Indexed: 07/04/2023]
Abstract
The different active roles of neurons and astrocytes during neuronal activation are associated with the metabolic processes necessary to supply the energy needed for their respective tasks at rest and during neuronal activation. Metabolism, in turn, relies on the delivery of metabolites and removal of toxic byproducts through diffusion processes and the cerebral blood flow. A comprehensive mathematical model of brain metabolism should account not only for the biochemical processes and the interaction of neurons and astrocytes, but also the diffusion of metabolites. In the present article, we present a computational methodology based on a multidomain model of the brain tissue and a homogenization argument for the diffusion processes. In our spatially distributed compartment model, communication between compartments occur both through local transport fluxes, as is the case within local astrocyte-neuron complexes, and through diffusion of some substances in some of the compartments. The model assumes that diffusion takes place in the extracellular space (ECS) and in the astrocyte compartment. In the astrocyte compartment, the diffusion across the syncytium network is implemented as a function of gap junction strength. The diffusion process is implemented numerically by means of a finite element method (FEM) based spatial discretization, and robust stiff solvers are used to time integrate the resulting large system. Computed experiments show the effects of ECS tortuosity, gap junction strength and spatial anisotropy in the astrocyte network on the brain energy metabolism.
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Affiliation(s)
- Gideon Idumah
- Department of Mathematics, Applied Mathematics and Statistics, Case Western Reserve University, USA
| | - Erkki Somersalo
- Department of Mathematics, Applied Mathematics and Statistics, Case Western Reserve University, USA
| | - Daniela Calvetti
- Department of Mathematics, Applied Mathematics and Statistics, Case Western Reserve University, USA.
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4
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Ahamed F, Van Criekinge M, Wang ZJ, Kurhanewicz J, Larson P, Sriram R. Modeling hyperpolarized lactate signal dynamics in cells, patient-derived tissue slice cultures and murine models. NMR IN BIOMEDICINE 2021; 34:e4467. [PMID: 33415771 PMCID: PMC8423093 DOI: 10.1002/nbm.4467] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 12/10/2020] [Indexed: 05/31/2023]
Abstract
Determining the aggressiveness of renal cell carcinoma (RCC) noninvasively is a critical part of the diagnostic workup for treating this disease that kills more than 15,000 people annually in the USA. Recently, we have shown that not only the amount of lactate produced, as a consequence of the Warburg effect, but also its efflux out of the cell, is a critical marker of RCC aggressiveness and differentiating RCCs from benign renal tumors. Enzymatic conversions can now be measured in situ with hyperpolarized (HP) 13 C magnetic resonance (MR) on a sub-minute time scale. Using RCC models, we have shown that this technology can interrogate in real time both lactate production and compartmentalization, which are associated with tumor aggressiveness. The dynamic HP MR data have enabled us to robustly characterize parameters that have been elusive to measure directly in intact living cells and murine tumors thus far. Specifically, we were able to measure the same intracellular lactate longitudinal relaxation time in three RCC cell lines of 16.42 s, and lactate efflux rate ranging from 0.14 to 0.8 s-1 in the least to the most aggressive RCC cell lines and correlate it to monocarboxylate transporter isoform 4 expression. We also analyzed dynamic HP lactate and pyruvate data from orthotopic murine RCC tumors using a simplified one-compartment model, and showed comparable apparent pyruvate to lactate conversion rate (kPL ) values with those measured in vitro. This kinetic modeling was then extended to characterize the lactate dynamics in patient-derived living RCC tissue slices; and even without direct measurement of the extracellular lactate signal the efflux parameter was still assessed and was distinct between the benign renal tumors and RCCs. Across all these preclinical models, the rate parameters of kPL and lactate efflux correlated to cancer aggressiveness, demonstrating the validity of our modeling approach for noninvasive assessment of RCC aggressiveness.
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Affiliation(s)
- Fayyaz Ahamed
- University of California, Berkeley, Berkeley, California, USA
| | - Mark Van Criekinge
- Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Zhen J. Wang
- Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - John Kurhanewicz
- Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Peder Larson
- Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Renuka Sriram
- Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
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5
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Topping GJ, Hundshammer C, Nagel L, Grashei M, Aigner M, Skinner JG, Schulte RF, Schilling F. Acquisition strategies for spatially resolved magnetic resonance detection of hyperpolarized nuclei. MAGMA (NEW YORK, N.Y.) 2020; 33:221-256. [PMID: 31811491 PMCID: PMC7109201 DOI: 10.1007/s10334-019-00807-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 10/08/2019] [Accepted: 11/21/2019] [Indexed: 12/13/2022]
Abstract
Hyperpolarization is an emerging method in magnetic resonance imaging that allows nuclear spin polarization of gases or liquids to be temporarily enhanced by up to five or six orders of magnitude at clinically relevant field strengths and administered at high concentration to a subject at the time of measurement. This transient gain in signal has enabled the non-invasive detection and imaging of gas ventilation and diffusion in the lungs, perfusion in blood vessels and tissues, and metabolic conversion in cells, animals, and patients. The rapid development of this method is based on advances in polarizer technology, the availability of suitable probe isotopes and molecules, improved MRI hardware and pulse sequence development. Acquisition strategies for hyperpolarized nuclei are not yet standardized and are set up individually at most sites depending on the specific requirements of the probe, the object of interest, and the MRI hardware. This review provides a detailed introduction to spatially resolved detection of hyperpolarized nuclei and summarizes novel and previously established acquisition strategies for different key areas of application.
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Affiliation(s)
- Geoffrey J Topping
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Christian Hundshammer
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Luca Nagel
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Martin Grashei
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Maximilian Aigner
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Jason G Skinner
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | | | - Franz Schilling
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany.
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Elevated Tumor Lactate and Efflux in High-grade Prostate Cancer demonstrated by Hyperpolarized 13C Magnetic Resonance Spectroscopy of Prostate Tissue Slice Cultures. Cancers (Basel) 2020; 12:cancers12030537. [PMID: 32110965 PMCID: PMC7139946 DOI: 10.3390/cancers12030537] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/23/2020] [Accepted: 02/24/2020] [Indexed: 12/11/2022] Open
Abstract
Non-invasive assessment of the biological aggressiveness of prostate cancer (PCa) is needed for men with localized disease. Hyperpolarized (HP) 13C magnetic resonance (MR) spectroscopy is a powerful approach to image metabolism, specifically the conversion of HP [1-13C]pyruvate to [1-13C]lactate, catalyzed by lactate dehydrogenase (LDH). Significant increase in tumor lactate was measured in high-grade PCa relative to benign and low-grade cancer, suggesting that HP 13C MR could distinguish low-risk (Gleason score ≤3 + 4) from high-risk (Gleason score ≥4 + 3) PCa. To test this and the ability of HP 13C MR to detect these metabolic changes, we cultured prostate tissues in an MR-compatible bioreactor under continuous perfusion. 31P spectra demonstrated good viability and dynamic HP 13C-pyruvate MR demonstrated that high-grade PCa had significantly increased lactate efflux compared to low-grade PCa and benign prostate tissue. These metabolic differences are attributed to significantly increased LDHA expression and LDH activity, as well as significantly increased monocarboxylate transporter 4 (MCT4) expression in high- versus low- grade PCa. Moreover, lactate efflux, LDH activity, and MCT4 expression were not different between low-grade PCa and benign prostate tissues, indicating that these metabolic alterations are specific for high-grade disease. These distinctive metabolic alterations can be used to differentiate high-grade PCa from low-grade PCa and benign prostate tissues using clinically translatable HP [1-13C]pyruvate MR.
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7
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Sapir G, Harris T, Uppala S, Nardi-Schreiber A, Sosna J, Gomori JM, Katz-Brull R. [ 13C 6,D 8]2-deoxyglucose phosphorylation by hexokinase shows selectivity for the β-anomer. Sci Rep 2019; 9:19683. [PMID: 31873121 PMCID: PMC6928223 DOI: 10.1038/s41598-019-56063-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 12/06/2019] [Indexed: 12/27/2022] Open
Abstract
A non-radioactive 2-deoxyglucose (2DG) analog has been developed here for hyperpolarized magnetic resonance investigations. The analog, [13C6,D8]2DG, showed 13% polarization in solution (27,000-fold signal enhancement at the C1 site), following a dissolution-DNP hyperpolarization process. The phosphorylation of this analog by yeast hexokinase (yHK) was monitored in real-time with a temporal resolution of 1 s. We show that yHK selectively utilizes the β anomer of the 2DG analog, thus revealing a surprising anomeric specificity of this reaction. Such anomeric selectivity was not observed for the reaction of yHK or bacterial glucokinase with a hyperpolarized glucose analog. yHK is highly similar to the human HK-2, which is overexpressed in malignancy. Thus, the current finding may shed a new light on a fundamental enzyme activity which is utilized in the most widespread molecular imaging technology for cancer detection - positron-emission tomography with 18F-2DG.
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Affiliation(s)
- Gal Sapir
- Department of Radiology, Hadassah Medical Center, Hebrew University of Jerusalem, The Faculty of Medicine, Jerusalem, Israel
| | - Talia Harris
- Department of Radiology, Hadassah Medical Center, Hebrew University of Jerusalem, The Faculty of Medicine, Jerusalem, Israel
| | - Sivaranjan Uppala
- Department of Radiology, Hadassah Medical Center, Hebrew University of Jerusalem, The Faculty of Medicine, Jerusalem, Israel
| | - Atara Nardi-Schreiber
- Department of Radiology, Hadassah Medical Center, Hebrew University of Jerusalem, The Faculty of Medicine, Jerusalem, Israel
| | - Jacob Sosna
- Department of Radiology, Hadassah Medical Center, Hebrew University of Jerusalem, The Faculty of Medicine, Jerusalem, Israel
| | - J Moshe Gomori
- Department of Radiology, Hadassah Medical Center, Hebrew University of Jerusalem, The Faculty of Medicine, Jerusalem, Israel
| | - Rachel Katz-Brull
- Department of Radiology, Hadassah Medical Center, Hebrew University of Jerusalem, The Faculty of Medicine, Jerusalem, Israel.
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8
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Peeters TH, Kobus T, Breukels V, Lenting K, Veltien A, Heerschap A, Scheenen TWJ. Imaging Hyperpolarized Pyruvate and Lactate after Blood-Brain Barrier Disruption with Focused Ultrasound. ACS Chem Neurosci 2019; 10:2591-2601. [PMID: 30873831 PMCID: PMC6523999 DOI: 10.1021/acschemneuro.9b00085] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
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Imaging of hyperpolarized 13C-labeled substrates has
emerged as an important magnetic resonance (MR) technique to study
metabolic pathways in real time in vivo. Even though
this technique has found its way to clinical trials, in vivo dynamic nuclear polarization is still mostly applied in preclinical
models. Its tremendous increase in signal-to-noise ratio (SNR) overcomes
the intrinsically low MR sensitivity of the 13C nucleus
and allows real-time metabolic imaging in small structures like the
mouse brain. However, applications in brain research are limited as
delivery of hyperpolarized compounds is restrained by the blood–brain
barrier (BBB). A local noninvasive disruption of the BBB could facilitate
delivery of hyperpolarized substrates and create opportunities to
study metabolic pathways in the brain that are generally not within
reach. In this work, we designed a setup to apply BBB disruption in
the mouse brain by MR-guided focused ultrasound (FUS) prior to MR
imaging of 13C-enriched hyperpolarized [1-13C]-pyruvate and its conversion to [1-13C]-lactate. To
overcome partial volume issues, we optimized a fast multigradient-echo
imaging method (temporal resolution of 2.4 s) with an in-plane spatial
resolution of 1.6 × 1.6 mm2, without the need of processing
large amounts of spectroscopic data. We demonstrated the feasibility
to apply 13C imaging in less than 1 h after FUS treatment
and showed a locally disrupted BBB during the time window of the whole
experiment. From detected hyperpolarized pyruvate and lactate signals
in both FUS-treated and untreated mice, we conclude that even at high
spatial resolution, signals from the blood compartment dominate in
the 13C images, leaving the interpretation of hyperpolarized
signals in the mouse brain challenging.
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Affiliation(s)
- Tom H. Peeters
- Department of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, The Netherlands
| | - Thiele Kobus
- Department of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, The Netherlands
| | - Vincent Breukels
- Department of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, The Netherlands
| | - Krissie Lenting
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Andor Veltien
- Department of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, The Netherlands
| | - Arend Heerschap
- Department of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, The Netherlands
| | - Tom W. J. Scheenen
- Department of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, The Netherlands
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9
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Performance analysis of an oxidase/peroxidase-based mediatorless amperometric biosensor. J Electroanal Chem (Lausanne) 2019. [DOI: 10.1016/j.jelechem.2019.04.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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10
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Zhu X, Gordon JW, Bok RA, Kurhanewicz J, Larson PEZ. Dynamic diffusion-weighted hyperpolarized 13 C imaging based on a slice-selective double spin echo sequence for measurements of cellular transport. Magn Reson Med 2018; 81:2001-2010. [PMID: 30368893 DOI: 10.1002/mrm.27501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 07/27/2018] [Accepted: 07/29/2018] [Indexed: 12/22/2022]
Abstract
PURPOSE To develop a pulse sequence to dynamically measure the ADC of hyperpolarized substrates during their perfusion, metabolic conversion, and transport. METHODS We proposed a slice-selective double spin echo sequence for dynamic hyperpolarized 13 C diffusion-weighted imaging. The proposed pulse sequence was optimized for a high field preclinical scanner through theoretical analysis and simulation. The performance of the method was compared to non-slice-selective double spin echo via in vivo studies. We also validated the sequence for dynamic ADC measurement in both phantom studies and transgenic mouse model of prostate cancer studies. RESULTS The optimized pulse sequence outperforms the traditional sequence with smaller saturation effects on the magnetization of hyperpolarized compounds that allowed more dynamic imaging frames covering a longer imaging time window. In pre-clinical studies (N = 8), the dynamic hyperpolarized lactate ADC maps of 6 studies in the prostate tumors showed an increase measured ADC over time, which might be related to lactate efflux from the tumor cells. CONCLUSIONS The proposed sequence was validated and shown to improve dynamic diffusion weighted imaging compared to the traditional double spin echo sequence, providing ADC maps of lactate through time.
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Affiliation(s)
- Xucheng Zhu
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California.,UCSF/UC Berkeley Graduate Program in Bioengineering, University of California, San Francisco, California
| | - Jeremy W Gordon
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California
| | - Robert A Bok
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California
| | - John Kurhanewicz
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California
| | - Peder E Z Larson
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California.,UCSF/UC Berkeley Graduate Program in Bioengineering, University of California, San Francisco, California
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11
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Zhang G, Ahola S, Lerche MH, Telkki VV, Hilty C. Identification of Intracellular and Extracellular Metabolites in Cancer Cells Using 13C Hyperpolarized Ultrafast Laplace NMR. Anal Chem 2018; 90:11131-11137. [PMID: 30125087 PMCID: PMC6168181 DOI: 10.1021/acs.analchem.8b03096] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
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Ultrafast
Laplace NMR (UF-LNMR), which is based on the spatial
encoding of multidimensional data, enables one to carry out 2D relaxation
and diffusion measurements in a single scan. Besides reducing the
experiment time to a fraction, it significantly facilitates the use
of nuclear spin hyperpolarization to boost experimental sensitivity,
because the time-consuming polarization step does not need to be repeated.
Here we demonstrate the usability of hyperpolarized UF-LNMR in the
context of cell metabolism, by investigating the conversion of pyruvate
to lactate in the cultures of mouse 4T1 cancer cells. We show that 13C ultrafast diffusion–T2 relaxation correlation measurements, with the sensitivity enhanced
by several orders of magnitude by dissolution dynamic nuclear polarization
(D-DNP), allows the determination of the extra- vs intracellular
location of metabolites because of their significantly different values
of diffusion coefficients and T2 relaxation
times. Under the current conditions, pyruvate was located predominantly
in the extracellular pool, while lactate remained primarily intracellular.
Contrary to the small flip angle diffusion methods reported in the
literature, the UF-LNMR method does not require several scans with
varying gradient strength, and it provides a combined diffusion and T2 contrast. Furthermore, the ultrafast concept
can be extended to various other multidimensional LNMR experiments,
which will provide detailed information about the dynamics and exchange
processes of cell metabolites.
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Affiliation(s)
- Guannan Zhang
- Department of Chemistry , Texas A&M University , 3255 TAMU, College Station , Texas 77843 , United States
| | - Susanna Ahola
- NMR Research Unit, Faculty of Science , University of Oulu , P.O. Box 3000, 90014 Oulu , Finland
| | - Mathilde H Lerche
- Department of Electrical Engineering, Center for Hyperpolarization in Magnetic Resonance , Technical University of Denmark , Building 349, DK-2800 Kgs Lyngby , Denmark
| | - Ville-Veikko Telkki
- NMR Research Unit, Faculty of Science , University of Oulu , P.O. Box 3000, 90014 Oulu , Finland
| | - Christian Hilty
- Department of Chemistry , Texas A&M University , 3255 TAMU, College Station , Texas 77843 , United States
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Marco-Rius I, Gordon JW, Mattis AN, Bok R, Santos RD, Sukumar S, Larson PE, Vigneron DB, Ohliger MA. Diffusion-weighted imaging of hyperpolarized [ 13 C]urea in mouse liver. J Magn Reson Imaging 2018; 47:141-151. [PMID: 28419644 PMCID: PMC5645231 DOI: 10.1002/jmri.25721] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 03/16/2017] [Indexed: 12/20/2022] Open
Abstract
PURPOSE To compare the apparent diffusion coefficient (ADC) of hyperpolarized (HP) [13 C,15 N]urea to the ADC of endogenous water in healthy and fibrotic mouse liver. MATERIALS AND METHODS ADC measurements for water and [13 C]urea were made in agarose phantoms at 14.1T. Next, the ADC of water and injected HP [13 C,15 N]urea were measured in eight CD1 mouse livers before and after induction of liver fibrosis using CCl4 . Liver fibrosis was quantified pathologically using the modified Brunt fibrosis score and compared to the measured ADC of water and urea. RESULTS In cell-free phantoms with 12.5% agarose, water ADC was nearly twice the ADC of urea (1.93 × 10-3 mm2 /s vs. 1.00 × 10-3 mm2 /s). The mean ADC values of water and [13 C,15 N]urea in healthy mouse liver (±SD) were nearly identical [(0.75 ± 0.11) × 10-3 mm2 /s and (0.75 ± 0.22) × 10-3 mm2 /s, respectively]. Mean water and [13 C,15 N]urea ADC values in fibrotic liver (±SD) were (0.84 ± 0.22) × 10-3 mm2 /s and (0.75 ± 0.15) × 10-3 mm2 /s, respectively. Neither water nor urea ADCs were statistically different in the fibrotic livers compared to baseline (P = 0.14 and P = 0.99, respectively). Water and urea ADCs were positively correlated at baseline (R2 = 0.52 and P = 0.045) but not in fibrotic livers (R2 = 0.23 and P = 0.23). CONCLUSION ADC of injected hyperpolarized urea in healthy liver reflects a smaller change as compared to free solution than ADC of water. This may reflect differences in cellular compartmentalization of the two compounds. No significant change in ADC of either water or urea were observed in relatively mild stages of liver fibrosis. LEVEL OF EVIDENCE 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:141-151.
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Affiliation(s)
- Irene Marco-Rius
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Jeremy W. Gordon
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Aras N. Mattis
- Department of Pathology, University of California San Francisco, San Francisco, California, USA
- UCSF Liver Center University of California San Francisco, San Francisco, California, USA
| | - Robert Bok
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Romelyn Delos Santos
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Subramanian Sukumar
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Peder E.Z. Larson
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Daniel B. Vigneron
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
- UCSF Liver Center University of California San Francisco, San Francisco, California, USA
| | - Michael A. Ohliger
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
- UCSF Liver Center University of California San Francisco, San Francisco, California, USA
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13
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Mikkelsen EFR, Mariager CØ, Nørlinger T, Qi H, Schulte RF, Jakobsen S, Frøkiær J, Pedersen M, Stødkilde-Jørgensen H, Laustsen C. Hyperpolarized [1- 13C]-acetate Renal Metabolic Clearance Rate Mapping. Sci Rep 2017; 7:16002. [PMID: 29167446 PMCID: PMC5700138 DOI: 10.1038/s41598-017-15929-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 11/03/2017] [Indexed: 01/02/2023] Open
Abstract
11C-acetate is a positron emission tomography (PET) tracer of oxidative metabolism, whereas hyperpolarized 13C-acetate can be used in magnetic resonance imaging (MRI) for investigating specific metabolic processes. The aims of this study were to examine if the kinetic formalism of 11C-acetate PET in the kidneys is comparable to that of 13C-acetate MRI, and to compare the dynamic metabolic information of hyperpolarized 13C-acetate MRI with that obtained with 11C-acetate PET. Rats were examined with dynamic hyperpolarized 13C-acetate MRI or 11C-acetate PET before and after intravenous injection of furosemide, a loop diuretic known to alter both the hemodynamics and oxygen consumption in the kidney. The metabolic clearance rates (MCR) were estimated and compared between the two modalities experimentally in vivo and in simulations. There was a clear dependency on the mean transit time and MCR for both 13C-acetate and 11C-acetate following furosemide administration, while no dependencies on the apparent renal perfusion were observed. This study demonstrated that hyperpolarized 13C-acetate MRI is feasible for measurements of the intrarenal energetic demand via the MCR, and that the quantitative measures are correlated with those measured by 11C-acetate PET, even though the temporal window is more than 30 times longer with 11C-acetate.
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Affiliation(s)
- Emmeli F R Mikkelsen
- MR Research Centre, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark.,Comparative Medicine Lab, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | | | - Thomas Nørlinger
- MR Research Centre, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark.,Comparative Medicine Lab, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Haiyun Qi
- MR Research Centre, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Rolf F Schulte
- GE healthcare, Freisinger Landstraße 50, 85748, Munich, Germany
| | - Steen Jakobsen
- Department of Nuclear Medicine and PET Center, Aarhus University Hospital, Nørrebrogade, 8000, Aarhus C, Denmark
| | - Jørgen Frøkiær
- Department of Nuclear Medicine and PET Center, Aarhus University Hospital, Nørrebrogade, 8000, Aarhus C, Denmark
| | - Michael Pedersen
- Comparative Medicine Lab, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Hans Stødkilde-Jørgensen
- MR Research Centre, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Christoffer Laustsen
- MR Research Centre, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark.
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14
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In-Vitro Dissolution Dynamic Nuclear Polarization for Sensitivity Enhancement of NMR with Biological Molecules. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2017; 1688:155-168. [PMID: 29151209 DOI: 10.1007/978-1-4939-7386-6_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Dissolution dynamic nuclear polarization (D-DNP) is a technique to prepare hyperpolarized nuclear spin states, yielding a signal enhancement of several orders of magnitude for liquid-state NMR. Here, we describe experimental procedures for the application of D-DNP in high-resolution NMR of biochemical compounds, to determine the time evolution of biochemical processes and intermolecular interactions.
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15
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Guduff L, Kurzbach D, van Heijenoort C, Abergel D, Dumez JN. Single-Scan 13
C Diffusion-Ordered NMR Spectroscopy of DNP-Hyperpolarised Substrates. Chemistry 2017; 23:16722-16727. [DOI: 10.1002/chem.201703300] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Ludmilla Guduff
- Institut de Chimie des Substances Naturelles; CNRS UPR2301; Univ. Paris Sud; Université Paris-Saclay; 91190 Gif-sur-Yvette France
| | - Dennis Kurzbach
- Laboratoire des Biomolécules; Département de chimie; Ecole normale supérieure; UPMC Univ. Paris 06; CNRS; PSL Research University; 75005 Paris France
- Laboratoire des Biomolécules; Sorbonne Universités; UPMC Univ. Paris 06; Ecole normale supérieure; CNRS; 75005 Paris France
| | - Carine van Heijenoort
- Institut de Chimie des Substances Naturelles; CNRS UPR2301; Univ. Paris Sud; Université Paris-Saclay; 91190 Gif-sur-Yvette France
| | - Daniel Abergel
- Laboratoire des Biomolécules; Département de chimie; Ecole normale supérieure; UPMC Univ. Paris 06; CNRS; PSL Research University; 75005 Paris France
- Laboratoire des Biomolécules; Sorbonne Universités; UPMC Univ. Paris 06; Ecole normale supérieure; CNRS; 75005 Paris France
| | - Jean-Nicolas Dumez
- Institut de Chimie des Substances Naturelles; CNRS UPR2301; Univ. Paris Sud; Université Paris-Saclay; 91190 Gif-sur-Yvette France
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16
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Reile I, Aspers RLEG, Tyburn JM, Kempf JG, Feiters MC, Rutjes FPJT, Tessari M. DOSY Analysis of Micromolar Analytes: Resolving Dilute Mixtures by SABRE Hyperpolarization. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201703577] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Indrek Reile
- Institute for Molecules and Materials; Radboud University; Heyendaalseweg 135 6525AJ Nijmegen The Netherlands
| | - Ruud L. E. G. Aspers
- Institute for Molecules and Materials; Radboud University; Heyendaalseweg 135 6525AJ Nijmegen The Netherlands
| | | | | | - Martin C. Feiters
- Institute for Molecules and Materials; Radboud University; Heyendaalseweg 135 6525AJ Nijmegen The Netherlands
| | - Floris P. J. T. Rutjes
- Institute for Molecules and Materials; Radboud University; Heyendaalseweg 135 6525AJ Nijmegen The Netherlands
| | - Marco Tessari
- Institute for Molecules and Materials; Radboud University; Heyendaalseweg 135 6525AJ Nijmegen The Netherlands
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17
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Reile I, Aspers RLEG, Tyburn JM, Kempf JG, Feiters MC, Rutjes FPJT, Tessari M. DOSY Analysis of Micromolar Analytes: Resolving Dilute Mixtures by SABRE Hyperpolarization. Angew Chem Int Ed Engl 2017; 56:9174-9177. [DOI: 10.1002/anie.201703577] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 05/25/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Indrek Reile
- Institute for Molecules and Materials; Radboud University; Heyendaalseweg 135 6525AJ Nijmegen The Netherlands
| | - Ruud L. E. G. Aspers
- Institute for Molecules and Materials; Radboud University; Heyendaalseweg 135 6525AJ Nijmegen The Netherlands
| | | | | | - Martin C. Feiters
- Institute for Molecules and Materials; Radboud University; Heyendaalseweg 135 6525AJ Nijmegen The Netherlands
| | - Floris P. J. T. Rutjes
- Institute for Molecules and Materials; Radboud University; Heyendaalseweg 135 6525AJ Nijmegen The Netherlands
| | - Marco Tessari
- Institute for Molecules and Materials; Radboud University; Heyendaalseweg 135 6525AJ Nijmegen The Netherlands
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18
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Kubala E, Muñoz-Álvarez KA, Topping G, Hundshammer C, Feuerecker B, Gómez PA, Pariani G, Schilling F, Glaser SJ, Schulte RF, Menzel MI, Schwaiger M. Hyperpolarized 13C Metabolic Magnetic Resonance Spectroscopy and Imaging. J Vis Exp 2016:54751. [PMID: 28060330 PMCID: PMC5226623 DOI: 10.3791/54751] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2023] Open
Abstract
In the past decades, new methods for tumor staging, restaging, treatment response monitoring, and recurrence detection of a variety of cancers have emerged in conjunction with the state-of-the-art positron emission tomography with 18F-fluorodeoxyglucose ([18F]-FDG PET). 13C magnetic resonance spectroscopic imaging (13CMRSI) is a minimally invasive imaging method that enables the monitoring of metabolism in vivo and in real time. As with any other method based on 13C nuclear magnetic resonance (NMR), it faces the challenge of low thermal polarization and a subsequent low signal-to-noise ratio due to the relatively low gyromagnetic ratio of 13C and its low natural abundance in biological samples. By overcoming these limitations, dynamic nuclear polarization (DNP) with subsequent sample dissolution has recently enabled commonly used NMR and magnetic resonance imaging (MRI) systems to measure, study, and image key metabolic pathways in various biological systems. A particularly interesting and promising molecule used in 13CMRSI is [1-13C]pyruvate, which, in the last ten years, has been widely used for in vitro, preclinical, and, more recently, clinical studies to investigate the cellular energy metabolism in cancer and other diseases. In this article, we outline the technique of dissolution DNP using a 3.35 T preclinical DNP hyperpolarizer and demonstrate its usage in in vitro studies. A similar protocol for hyperpolarization may be applied for the most part in in vivo studies as well. To do so, we used lactate dehydrogenase (LDH) and catalyzed the metabolic reaction of [1-13C]pyruvate to [1-13C]lactate in a prostate carcinoma cell line, PC3, in vitro using 13CMRSI.
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Affiliation(s)
- Eugen Kubala
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München; Department of Chemistry, Technische Universität München; GE Global Research;
| | - Kim A Muñoz-Álvarez
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München
| | - Geoffrey Topping
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München
| | - Christian Hundshammer
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München; Department of Chemistry, Technische Universität München
| | - Benedikt Feuerecker
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München
| | - Pedro A Gómez
- GE Global Research; Zentralinstitut für Medizintechnik der Technischen Universität München (IMETUM), Technische Universität München
| | - Giorgio Pariani
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München; Institute for Biological and Medical Imaging (IBMI), Helmholtz Zentrum München; IDG Institute of Developmental Genetics, Helmholtz Zentrum München
| | - Franz Schilling
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München
| | | | | | | | - Markus Schwaiger
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München
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19
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Gordon JW, Milshteyn E, Marco-Rius I, Ohliger M, Vigneron DB, Larson PEZ. Mis-estimation and bias of hyperpolarized apparent diffusion coefficient measurements due to slice profile effects. Magn Reson Med 2016; 78:1087-1092. [PMID: 27735082 DOI: 10.1002/mrm.26482] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 07/18/2016] [Accepted: 09/03/2016] [Indexed: 12/16/2022]
Abstract
PURPOSE The purpose of this work was to explore the impact of slice profile effects on apparent diffusion coefficient (ADC) mapping of hyperpolarized (HP) substrates. METHODS Slice profile effects were simulated using a Gaussian radiofrequency (RF) pulse with a variety of flip angle schedules and b-value ordering schemes. A long T1 water phantom was used to validate the simulation results, and ADC mapping of HP [13 C,15 N2 ]urea was performed on the murine liver to assess these effects in vivo. RESULTS Slice profile effects result in excess signal after repeated RF pulses, causing bias in HP measurements. The largest error occurs for metabolites with small ADCs, resulting in up to 10-fold overestimation for metabolites that are in more-restricted environments. A mixed b-value scheme substantially reduces this bias, whereas scaling the slice-select gradient can mitigate it completely. In vivo, the liver ADC of hyperpolarized [13 C,15 N2 ]urea is nearly 70% lower (0.99 ± 0.22 vs 1.69 ± 0.21 × 10-3 mm2 /s) when slice-select gradient scaling is used. CONCLUSION Slice profile effects can lead to bias in HP ADC measurements. A mixed b-value ordering scheme can reduce this bias compared to sequential b-value ordering. Slice-select gradient scaling can also correct for this deviation, minimizing bias and providing more-precise ADC measurements of HP substrates. Magn Reson Med 78:1087-1092, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Jeremy W Gordon
- Department of Radiology & Biomedical Imaging, UCSF, San Francisco, California, USA
| | - Eugene Milshteyn
- Department of Radiology & Biomedical Imaging, UCSF, San Francisco, California, USA
| | - Irene Marco-Rius
- Department of Radiology & Biomedical Imaging, UCSF, San Francisco, California, USA
| | - Michael Ohliger
- Department of Radiology & Biomedical Imaging, UCSF, San Francisco, California, USA
| | - Daniel B Vigneron
- Department of Radiology & Biomedical Imaging, UCSF, San Francisco, California, USA
| | - Peder E Z Larson
- Department of Radiology & Biomedical Imaging, UCSF, San Francisco, California, USA
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20
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Koelsch BL, Sriram R, Keshari KR, Leon Swisher C, Van Criekinge M, Sukumar S, Vigneron DB, Wang ZJ, Larson PEZ, Kurhanewicz J. Separation of extra- and intracellular metabolites using hyperpolarized (13)C diffusion weighted MR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 270:115-123. [PMID: 27434780 PMCID: PMC5448422 DOI: 10.1016/j.jmr.2016.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 07/06/2016] [Accepted: 07/07/2016] [Indexed: 05/07/2023]
Abstract
This work demonstrates the separation of extra- and intracellular components of glycolytic metabolites with diffusion weighted hyperpolarized (13)C magnetic resonance spectroscopy. Using b-values of up to 15,000smm(-2), a multi-exponential signal response was measured for hyperpolarized [1-(13)C] pyruvate and lactate. By fitting the fast and slow asymptotes of these curves, their extra- and intracellular weighted diffusion coefficients were determined in cells perfused in a MR compatible bioreactor. In addition to measuring intracellular weighted diffusion, extra- and intracellular weighted hyperpolarized (13)C metabolites pools are assessed in real-time, including their modulation with inhibition of monocarboxylate transporters. These studies demonstrate the ability to simultaneously assess membrane transport in addition to enzymatic activity with the use of diffusion weighted hyperpolarized (13)C MR. This technique could be an indispensible tool to evaluate the impact of microenvironment on the presence, aggressiveness and metastatic potential of a variety of cancers.
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Affiliation(s)
- Bertram L Koelsch
- Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA; UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, Berkeley and University of California, San Francisco, CA, USA
| | - Renuka Sriram
- Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA.
| | - Kayvan R Keshari
- Radiology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA; Weill Cornell Medical College, New York, NY, USA
| | - Christine Leon Swisher
- Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA; UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, Berkeley and University of California, San Francisco, CA, USA
| | - Mark Van Criekinge
- Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
| | - Subramaniam Sukumar
- Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
| | - Daniel B Vigneron
- Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA; UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, Berkeley and University of California, San Francisco, CA, USA
| | - Zhen J Wang
- Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
| | - Peder E Z Larson
- Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA; UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, Berkeley and University of California, San Francisco, CA, USA
| | - John Kurhanewicz
- Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA; UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, Berkeley and University of California, San Francisco, CA, USA
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21
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Salamanca-Cardona L, Keshari KR. (13)C-labeled biochemical probes for the study of cancer metabolism with dynamic nuclear polarization-enhanced magnetic resonance imaging. Cancer Metab 2015; 3:9. [PMID: 26380082 PMCID: PMC4570227 DOI: 10.1186/s40170-015-0136-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 09/07/2015] [Indexed: 11/30/2022] Open
Abstract
In recent years, advances in metabolic imaging have become dependable tools for the diagnosis and treatment assessment in cancer. Dynamic nuclear polarization (DNP) has recently emerged as a promising technology in hyperpolarized (HP) magnetic resonance imaging (MRI) and has reached clinical relevance with the successful visualization of [1-13C] pyruvate as a molecular imaging probe in human prostate cancer. This review focuses on introducing representative compounds relevant to metabolism that are characteristic of cancer tissue: aerobic glycolysis and pyruvate metabolism, glutamine addiction and glutamine/glutamate metabolism, and the redox state and ascorbate/dehydroascorbate metabolism. In addition, a brief introduction of probes that can be used to trace necrosis, pH changes, and other pathways relevant to cancer is presented to demonstrate the potential that HP MRI has to revolutionize the use of molecular imaging for diagnosis and assessment of treatments in cancer.
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Affiliation(s)
- Lucia Salamanca-Cardona
- Department of Radiology and Molecular Pharmacology and Chemistry Program, Memorial Sloan Kettering Cancer Center (MSKCC), 1275 York Avenue, New York, NY 10065 USA
| | - Kayvan R Keshari
- Department of Radiology and Molecular Pharmacology and Chemistry Program, Memorial Sloan Kettering Cancer Center (MSKCC), 1275 York Avenue, New York, NY 10065 USA
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22
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Koelsch BL, Reed GD, Keshari KR, Chaumeil MM, Bok R, Ronen SM, Vigneron DB, Kurhanewicz J, Larson PEZ. Rapid in vivo apparent diffusion coefficient mapping of hyperpolarized (13) C metabolites. Magn Reson Med 2015; 74:622-633. [PMID: 25213126 PMCID: PMC4362805 DOI: 10.1002/mrm.25422] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 07/01/2014] [Accepted: 08/01/2014] [Indexed: 12/22/2022]
Abstract
PURPOSE Hyperpolarized (13) C magnetic resonance allows for the study of real-time metabolism in vivo, including significant hyperpolarized (13) C lactate production in many tumors. Other studies have shown that aggressive and highly metastatic tumors rapidly transport lactate out of cells. Thus, the ability to not only measure the production of hyperpolarized (13) C lactate but also understand its compartmentalization using diffusion-weighted MR will provide unique information for improved tumor characterization. METHODS We used a bipolar, pulsed-gradient, double spin echo imaging sequence to rapidly generate diffusion-weighted images of hyperpolarized (13) C metabolites. Our methodology included a simultaneously acquired B1 map to improve apparent diffusion coefficient (ADC) accuracy and a diffusion-compensated variable flip angle scheme to improve ADC precision. RESULTS We validated this sequence and methodology in hyperpolarized (13) C phantoms. Next, we generated ADC maps of several hyperpolarized (13) C metabolites in a normal rat, rat brain tumor, and prostate cancer mouse model using both preclinical and clinical trial-ready hardware. CONCLUSION ADC maps of hyperpolarized (13) C metabolites provide information about the localization of these molecules in the tissue microenvironment. The methodology presented here allows for further studies to investigate ADC changes due to disease state that may provide unique information about cancer aggressiveness and metastatic potential.
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Affiliation(s)
- Bertram L. Koelsch
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
- UC Berkeley – UCSF Graduate Program in Bioengineering, University of California, Berkeley and University of California, San Francisco, California, USA
| | - Galen D. Reed
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
- UC Berkeley – UCSF Graduate Program in Bioengineering, University of California, Berkeley and University of California, San Francisco, California, USA
| | - Kayvan R. Keshari
- Department of Radiology and Molecular Pharmacology and Chemistry Program, Memorial Sloan Kettering Cancer Center, New York, USA
| | - Myriam M. Chaumeil
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Robert Bok
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Sabrina M. Ronen
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
- UC Berkeley – UCSF Graduate Program in Bioengineering, University of California, Berkeley and University of California, San Francisco, California, USA
| | - Daniel B. Vigneron
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
- UC Berkeley – UCSF Graduate Program in Bioengineering, University of California, Berkeley and University of California, San Francisco, California, USA
| | - John Kurhanewicz
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
- UC Berkeley – UCSF Graduate Program in Bioengineering, University of California, Berkeley and University of California, San Francisco, California, USA
| | - Peder E. Z. Larson
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
- UC Berkeley – UCSF Graduate Program in Bioengineering, University of California, Berkeley and University of California, San Francisco, California, USA
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23
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Bakermans AJ, Abdurrachim D, Moonen RPM, Motaal AG, Prompers JJ, Strijkers GJ, Vandoorne K, Nicolay K. Small animal cardiovascular MR imaging and spectroscopy. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2015; 88-89:1-47. [PMID: 26282195 DOI: 10.1016/j.pnmrs.2015.03.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 03/09/2015] [Accepted: 03/09/2015] [Indexed: 06/04/2023]
Abstract
The use of MR imaging and spectroscopy for studying cardiovascular disease processes in small animals has increased tremendously over the past decade. This is the result of the remarkable advances in MR technologies and the increased availability of genetically modified mice. MR techniques provide a window on the entire timeline of cardiovascular disease development, ranging from subtle early changes in myocardial metabolism that often mark disease onset to severe myocardial dysfunction associated with end-stage heart failure. MR imaging and spectroscopy techniques play an important role in basic cardiovascular research and in cardiovascular disease diagnosis and therapy follow-up. This is due to the broad range of functional, structural and metabolic parameters that can be quantified by MR under in vivo conditions non-invasively. This review describes the spectrum of MR techniques that are employed in small animal cardiovascular disease research and how the technological challenges resulting from the small dimensions of heart and blood vessels as well as high heart and respiratory rates, particularly in mice, are tackled.
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Affiliation(s)
- Adrianus J Bakermans
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Desiree Abdurrachim
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Rik P M Moonen
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Abdallah G Motaal
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Jeanine J Prompers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Gustav J Strijkers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Katrien Vandoorne
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Klaas Nicolay
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
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24
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Chaumeil MM, Najac C, Ronen SM. Studies of Metabolism Using (13)C MRS of Hyperpolarized Probes. Methods Enzymol 2015; 561:1-71. [PMID: 26358901 DOI: 10.1016/bs.mie.2015.04.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
First described in 2003, the dissolution dynamic nuclear polarization (DNP) technique, combined with (13)C magnetic resonance spectroscopy (MRS), has since been used in numerous metabolic studies and has become a valuable metabolic imaging method. DNP dramatically increases the level of polarization of (13)C-labeled compounds resulting in an increase in the signal-to-noise ratio (SNR) of over 50,000 fold for the MRS spectrum of hyperpolarized compounds. The high SNR enables rapid real-time detection of metabolism in cells, tissues, and in vivo. This chapter will present a comprehensive review of the DNP approaches that have been used to monitor metabolism in living systems. First, the list of (13)C DNP probes developed to date will be presented, with a particular focus on the most commonly used probe, namely [1-(13)C] pyruvate. In the next four sections, we will then describe the different factors that need to be considered when designing (13)C DNP probes for metabolic studies, conducting in vitro or in vivo hyperpolarized experiments, as well as acquiring, analyzing, and modeling hyperpolarized (13)C data.
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Affiliation(s)
- Myriam M Chaumeil
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Chloé Najac
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Sabrina M Ronen
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA.
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25
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Gordon JW, Niles DJ, Adamson EB, Johnson KM, Fain SB. Application of flow sensitive gradients for improved measures of metabolism using hyperpolarized (13) c MRI. Magn Reson Med 2015; 75:1242-8. [PMID: 25951611 DOI: 10.1002/mrm.25584] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 11/23/2014] [Accepted: 11/25/2014] [Indexed: 12/26/2022]
Abstract
PURPOSE To develop the use of bipolar gradients to suppress partial-volume and flow-related artifacts from macrovascular, hyperpolarized spins. THEORY AND METHODS Digital simulations were performed over a range of spatial resolutions and gradient strengths to determine the optimal bipolar gradient strength and duration to suppress flowing spins while minimizing signal loss from static tissue. In vivo experiments were performed to determine the efficacy of this technique to suppress vascular signal in the study of hyperpolarized [1-(13)C]pyruvate renal metabolism. RESULTS Digital simulations showed that in the absence of bipolar gradients, partial-volume artifacts from the vasculature were still present, causing underestimation of the apparent reaction rate of pyruvate to lactate (kP). The addition of a bipolar gradient with b = 32 s/mm(2) sufficiently suppressed the vascular signal without a substantial decrease in signal from static tissue. In vivo results corroborate digital simulations, with similar peak lactate signal to noise ratio (SNR) but substantially different kP in the presence of bipolar gradients. CONCLUSION The proposed approach suppresses signal from flowing spins while minimizing signal loss from static tissue, removing contaminating signal from the vasculature and increasing kinetic modeling accuracy without substantially sacrificing SNR or temporal resolution.
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Affiliation(s)
- Jeremy W Gordon
- Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - David J Niles
- Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Erin B Adamson
- Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Kevin M Johnson
- Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Sean B Fain
- Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA.,Radiology, University of Wisconsin-Madison, Madison, Madison, Wisconsin, USA.,Biomedical Engineering, University of Wisconsin-Madison, Madison, Madison, Wisconsin, USA
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26
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Søgaard LV, Schilling F, Janich MA, Menzel MI, Ardenkjaer-Larsen JH. In vivo measurement of apparent diffusion coefficients of hyperpolarized ¹³C-labeled metabolites. NMR IN BIOMEDICINE 2014; 27:561-9. [PMID: 24664927 DOI: 10.1002/nbm.3093] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 01/09/2014] [Accepted: 01/22/2014] [Indexed: 05/14/2023]
Abstract
The combination of hyperpolarized MRS with diffusion weighting (dw) allows for determination of the apparent diffusion coefficient (ADC), which is indicative of the intra- or extracellular localization of the metabolite. Here, a slice-selective pulsed-gradient spin echo sequence was implemented to acquire a series of dw spectra from rat muscle in vivo to determine the ADCs of multiple metabolites after a single injection of hyperpolarized [1- ¹³C]pyruvate. An optimal control optimized universal-rotation pulse was used for refocusing to minimize signal loss caused by B1 imperfections. Non-dw spectra were acquired interleaved with the dw spectra and these were used to correct for signal decay during the acquisition as a result of T1 decay, pulse imperfections, flow etc. The data showed that the ADC values for [1- ¹³C]lactate (0.4-0.7 µm² /ms) and [1- ¹³C]alanine (0.4-0.9 µm² /ms) were about a factor of two lower than the ADC of [1- ¹³C]pyruvate (1.1-1.5 µm²/ms). This indicates a more restricted diffusion space for the former two metabolites consistent with lactate and alanine being intracellular. The higher ADC for pyruvate (similar to the proton ADC) reflected that the injected substance was not confined inside the muscle cells but also present extracellular.
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Affiliation(s)
- Lise Vejby Søgaard
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Denmark
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27
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Reed GD, von Morze C, Bok R, Koelsch BL, Van Criekinge M, Smith KJ, Shang H, Larson PEZ, Kurhanewicz J, Vigneron DB. High resolution (13)C MRI with hyperpolarized urea: in vivo T(2) mapping and (15)N labeling effects. IEEE TRANSACTIONS ON MEDICAL IMAGING 2014; 33:362-71. [PMID: 24235273 PMCID: PMC4011557 DOI: 10.1109/tmi.2013.2285120] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
(13)C steady state free precession (SSFP) magnetic resonance imaging and effective spin-spin relaxation time (T2) mapping were performed using hyperpolarized [(13)C] urea and [(13) C,(15)N2] urea injected intravenously in rats. (15)N labeling gave large T2 increases both in solution and in vivo due to the elimination of a strong scalar relaxation pathway. The T2 increase was pronounced in the kidney, with [(13) C,(15) N2] urea giving T2 values of 6.3±1.3 s in the cortex and medulla, and 11±2 s in the renal pelvis. The measured T2 in the aorta was 1.3±0.3 s. [(13)C] urea showed shortened T2 values in the kidney of 0.23±0.03 s compared to 0.28±0.03 s measured in the aorta. The enhanced T2 of [(13)C,(15)N2] urea was utilized to generate large signal enhancement by SSFP acquisitions with flip angles approaching the fully refocused regime. Projection images at 0.94 mm in-plane resolution were acquired with both urea isotopes, with [(13)C,(15) N2] urea giving a greater than four-fold increase in signal-to-noise ratio over [(13)C] urea.
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Affiliation(s)
| | - Cornelius von Morze
- Radiology and Biomedical Imaging, University of California-San Francisco, San Francisco, CA 94143 USA ()
| | - Robert Bok
- Radiology and Biomedical Imaging, University of California-San Francisco, San Francisco, CA 94143 USA ()
| | - Bertram L. Koelsch
- Radiology and Biomedical Imaging, University of California-San Francisco, San Francisco, CA 94143 USA ()
| | - Mark Van Criekinge
- Radiology and Biomedical Imaging, University of California-San Francisco, San Francisco, CA 94143 USA ()
| | - Kenneth J. Smith
- Department of Chemistry, University of San Francisco, San Francisco, CA 94117 USA ()
| | - Hong Shang
- Radiology and Biomedical Imaging, University of California-San Francisco, San Francisco, CA 94143 USA ()
| | - Peder E. Z. Larson
- Radiology and Biomedical Imaging, University of California-San Francisco, San Francisco, CA 94143 USA ()
| | - John Kurhanewicz
- Radiology and Biomedical Imaging, University of California-San Francisco, San Francisco, CA 94143 USA ()
| | - Daniel B. Vigneron
- Radiology and Biomedical Imaging, University of California-San Francisco, San Francisco, CA 94143 USA ()
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28
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Keshari KR, Wilson DM. Chemistry and biochemistry of 13C hyperpolarized magnetic resonance using dynamic nuclear polarization. Chem Soc Rev 2013; 43:1627-59. [PMID: 24363044 DOI: 10.1039/c3cs60124b] [Citation(s) in RCA: 262] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The study of transient chemical phenomena by conventional NMR has proved elusive, particularly for non-(1)H nuclei. For (13)C, hyperpolarization using the dynamic nuclear polarization (DNP) technique has emerged as a powerful means to improve SNR. The recent development of rapid dissolution DNP methods has facilitated previously impossible in vitro and in vivo study of small molecules. This review presents the basics of the DNP technique, identification of appropriate DNP substrates, and approaches to increase hyperpolarized signal lifetimes. Also addressed are the biochemical events to which DNP-NMR has been applied, with descriptions of several probes that have met with in vivo success.
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Affiliation(s)
- Kayvan R Keshari
- Department of Radiology, Memorial Sloan-Kettering Cancer Center (MSKCC), New York, NY 10065, USA
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29
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Hill DK, Orton MR, Mariotti E, Boult JKR, Panek R, Jafar M, Parkes HG, Jamin Y, Miniotis MF, Al-Saffar NMS, Beloueche-Babari M, Robinson SP, Leach MO, Chung YL, Eykyn TR. Model free approach to kinetic analysis of real-time hyperpolarized 13C magnetic resonance spectroscopy data. PLoS One 2013; 8:e71996. [PMID: 24023724 PMCID: PMC3762840 DOI: 10.1371/journal.pone.0071996] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 07/11/2013] [Indexed: 02/05/2023] Open
Abstract
Real-time detection of the rates of metabolic flux, or exchange rates of endogenous enzymatic reactions, is now feasible in biological systems using Dynamic Nuclear Polarization Magnetic Resonance. Derivation of reaction rate kinetics from this technique typically requires multi-compartmental modeling of dynamic data, and results are therefore model-dependent and prone to misinterpretation. We present a model-free formulism based on the ratio of total areas under the curve (AUC) of the injected and product metabolite, for example pyruvate and lactate. A theoretical framework to support this novel analysis approach is described, and demonstrates that the AUC ratio is proportional to the forward rate constant k. We show that the model-free approach strongly correlates with k for whole cell in vitro experiments across a range of cancer cell lines, and detects response in cells treated with the pan-class I PI3K inhibitor GDC-0941 with comparable or greater sensitivity. The same result is seen in vivo with tumor xenograft-bearing mice, in control tumors and following drug treatment with dichloroacetate. An important finding is that the area under the curve is independent of both the input function and of any other metabolic pathways arising from the injected metabolite. This model-free approach provides a robust and clinically relevant alternative to kinetic model-based rate measurements in the clinical translation of hyperpolarized (13)C metabolic imaging in humans, where measurement of the input function can be problematic.
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Affiliation(s)
- Deborah K. Hill
- Cancer Research UK (CR-UK) and Engineering and Physical Sciences Research Council (EPSRC) Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Trust, Sutton, Surrey, United Kingdom
| | - Matthew R. Orton
- Cancer Research UK (CR-UK) and Engineering and Physical Sciences Research Council (EPSRC) Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Trust, Sutton, Surrey, United Kingdom
| | - Erika Mariotti
- Division of Imaging Sciences and Biomedical Engineering, Kings College London, St. Thomas Hospital, London, United Kingdom
| | - Jessica K. R. Boult
- Cancer Research UK (CR-UK) and Engineering and Physical Sciences Research Council (EPSRC) Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Trust, Sutton, Surrey, United Kingdom
| | - Rafal Panek
- Cancer Research UK (CR-UK) and Engineering and Physical Sciences Research Council (EPSRC) Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Trust, Sutton, Surrey, United Kingdom
| | - Maysam Jafar
- Cancer Research UK (CR-UK) and Engineering and Physical Sciences Research Council (EPSRC) Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Trust, Sutton, Surrey, United Kingdom
| | - Harold G. Parkes
- Cancer Research UK (CR-UK) and Engineering and Physical Sciences Research Council (EPSRC) Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Trust, Sutton, Surrey, United Kingdom
| | - Yann Jamin
- Cancer Research UK (CR-UK) and Engineering and Physical Sciences Research Council (EPSRC) Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Trust, Sutton, Surrey, United Kingdom
| | - Maria Falck Miniotis
- Cancer Research UK (CR-UK) and Engineering and Physical Sciences Research Council (EPSRC) Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Trust, Sutton, Surrey, United Kingdom
| | - Nada M. S. Al-Saffar
- Cancer Research UK (CR-UK) and Engineering and Physical Sciences Research Council (EPSRC) Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Trust, Sutton, Surrey, United Kingdom
| | - Mounia Beloueche-Babari
- Cancer Research UK (CR-UK) and Engineering and Physical Sciences Research Council (EPSRC) Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Trust, Sutton, Surrey, United Kingdom
| | - Simon P. Robinson
- Cancer Research UK (CR-UK) and Engineering and Physical Sciences Research Council (EPSRC) Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Trust, Sutton, Surrey, United Kingdom
| | - Martin O. Leach
- Cancer Research UK (CR-UK) and Engineering and Physical Sciences Research Council (EPSRC) Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Trust, Sutton, Surrey, United Kingdom
| | - Yuen-Li Chung
- Cancer Research UK (CR-UK) and Engineering and Physical Sciences Research Council (EPSRC) Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Trust, Sutton, Surrey, United Kingdom
| | - Thomas R. Eykyn
- Cancer Research UK (CR-UK) and Engineering and Physical Sciences Research Council (EPSRC) Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and Royal Marsden NHS Trust, Sutton, Surrey, United Kingdom
- Division of Imaging Sciences and Biomedical Engineering, Kings College London, St. Thomas Hospital, London, United Kingdom
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