Hyperpolarization of [1‐ 13 C]Ketoisocaproate‐d 2 by Reversible Exchange with Parahydrogen Enables Profiling of Branched‐Chain‐Amino‐Acid Metabolism in Cellulo and in Vivo
13 affiliations
- 1Division of Medical Physics Department of Radiology Medical Center ‐ University of Freiburg Faculty of Medicine ‐ University of Freiburg Freiburg Germany
- 2Faculty of Biology Albert Ludwigs University Freiburg Freiburg Germany
- 3German Cancer Consortium (DKTK) partner site Freiburg a Partnership Between DKFZ and University Medical Center Freiburg Heidelberg Germany
- 4Institute of Organic Chemistry and Center for Integrated Quantum Science and Technology (IQST) University of Ulm Ulm Germany
- 5Institute of Molecular Medicine and Cell Research Faculty of Medicine University of Freiburg Freiburg Germany
- 6NVision Imaging Technologies GmbH Ulm Germany
- 7Technical University of Munich TUM School of Medicine and Health Department of Nuclear Medicine TUM University Hospital Munich Germany
- 8German Cancer Consortium (DKTK), partner site Munich a Partnership Between DKFZ and TUM Heidelberg Germany
- 9Section Biomedical Imaging Molecular Imaging North Competence Center MOINCC Department of Radiology and Neuroradiology University Hospital Schleswig Holstein Kiel University Kiel Germany
- 10Cluster of Excellence iFIT (EXC 2180) “Image‐Guided and Functionally Instructed Tumor Therapies” Eberhard Karls University Tübingen Tübingen Germany
- 11German Cancer Consortium (DKTK), partner site Tübingen a Partnership Between DKFZ and University Hospital Tübingen Heidelberg Germany
- 12Werner Siemens Imaging Center Department of Preclinical Imaging and Radiopharmacy Eberhard Karls University Tübingen Tübingen Germany
- 13Centre for Biological Signalling Studies BIOSS University of Freiburg Freiburg Germany
Abstract
Hyperpolarized 1 3 C magnetic resonance imaging (MRI) is the only method to image metabolic fluxes in real time, non‐invasively, and in vivo. To date, however, most studies have used [1‐ 1 3 C]pyruvate and dynamic nuclear polarization (dDNP). Here, we establish efficient hyperpolarization (HP) of protio and partially‐deuterated [1‐ 1 3 C]ketoisocaproate (KIC) using Spin‐Lock‐Induced‐Crossing‐Signal Amplification by Reversible Exchange (SLIC‐SABRE), a high‐throughput, uncomplex and low‐cost method based on parahydrogen. We demonstrate 13 C polarization up to ≈28% and T 1 relaxation times > 200 s at 1 T in methanol‐d 4 . A rapid purification procedure allowed us to obtain biocompatible formulations with ≈11% 13 C polarization at the time of injection, sufficient for in cellulo and in vivo studies. We found that branched‐chain‐amino‐acid transaminase (BCAT) activity leads to HP [1‐ 1 3 C]leucine formation exclusively in BCAT1‐high MDA‐MB231 breast‐cancer cells, but not in BCAT1‐low MCF7 or PyB6 cells. In a proof‐of‐concept in vivo experiment, 13 C magnetic resonance spectroscopy imaging of the healthy mouse brain detected [1‐ 13 C]leucine formation after intravenous injection of SABRE [1‐ 13 C]KIC‐d 2 . Our results demonstrate that [1‐ 13 C]KIC‐d 2 provides a sensitive readout of BCAT1‐dependent metabolism and that SLIC‐SABRE can rapidly generate this probe for 13 C MRI, extending accessible parahydrogen‐based hyperpolarization to amino‐acid pathways relevant to cancer biology and chemoresistance.
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BibTeX
@article{petersen2026hyperpolarization,
title = {{Hyperpolarization of [1‐ 13 C]Ketoisocaproate‐d 2 by Reversible Exchange with Parahydrogen Enables Profiling of Branched‐Chain‐Amino‐Acid Metabolism in Cellulo and in Vivo}},
author = {Stefan Petersen and Philipp R. Groß and Paul M. Schmidt and Henri de Maissin and Asitan Rittinger and Robert Willing and Adriana Sacristán‐Martín and Lisa Heß and Jule Koch and Sebastian Lucas and Maxim Zaitsev and Dominik von Elverfeldt and Martin Grashei and Franz Schilling and Jan‐Bernd Hövener and André F. Martins and Max von Delius and Thomas Reinheckel and Andreas B. Schmidt},
journal = {Advanced Science},
year = {2026},
month = jun,
doi = {10.1002/advs.76213},
url = {https://doi.org/10.1002/advs.76213},
note = {CC BY},
}
RIS
TY - JOUR
TI - Hyperpolarization of [1‐ 13 C]Ketoisocaproate‐d 2 by Reversible Exchange with Parahydrogen Enables Profiling of Branched‐Chain‐Amino‐Acid Metabolism in Cellulo and in Vivo
AU - Stefan Petersen
AU - Philipp R. Groß
AU - Paul M. Schmidt
AU - Henri de Maissin
AU - Asitan Rittinger
AU - Robert Willing
AU - Adriana Sacristán‐Martín
AU - Lisa Heß
AU - Jule Koch
AU - Sebastian Lucas
AU - Maxim Zaitsev
AU - Dominik von Elverfeldt
AU - Martin Grashei
AU - Franz Schilling
AU - Jan‐Bernd Hövener
AU - André F. Martins
AU - Max von Delius
AU - Thomas Reinheckel
AU - Andreas B. Schmidt
PY - 2026
DA - 2026/06/23
JO - Advanced Science
DO - 10.1002/advs.76213
UR - https://doi.org/10.1002/advs.76213
AB - Hyperpolarized 1 3 C magnetic resonance imaging (MRI) is the only method to image metabolic fluxes in real time, non‐invasively, and in vivo. To date, however, most studies have used [1‐ 1 3 C]pyruvate and dynamic nuclear polarization (dDNP). Here, we establish efficient hyperpolarization (HP) of protio and partially‐deuterated [1‐ 1 3 C]ketoisocaproate (KIC) using Spin‐Lock‐Induced‐Crossing‐Signal Amplification by Reversible Exchange (SLIC‐SABRE), a high‐throughput, uncomplex and low‐cost method based on parahydrogen. We demonstrate 13 C polarization up to ≈28% and T 1 relaxation times > 200 s at 1 T in methanol‐d 4 . A rapid purification procedure allowed us to obtain biocompatible formulations with ≈11% 13 C polarization at the time of injection, sufficient for in cellulo and in vivo studies. We found that branched‐chain‐amino‐acid transaminase (BCAT) activity leads to HP [1‐ 1 3 C]leucine formation exclusively in BCAT1‐high MDA‐MB231 breast‐cancer cells, but not in BCAT1‐low MCF7 or PyB6 cells. In a proof‐of‐concept in vivo experiment, 13 C magnetic resonance spectroscopy imaging of the healthy mouse brain detected [1‐ 13 C]leucine formation after intravenous injection of SABRE [1‐ 13 C]KIC‐d 2 . Our results demonstrate that [1‐ 13 C]KIC‐d 2 provides a sensitive readout of BCAT1‐dependent metabolism and that SLIC‐SABRE can rapidly generate this probe for 13 C MRI, extending accessible parahydrogen‐based hyperpolarization to amino‐acid pathways relevant to cancer biology and chemoresistance.
SN - 2198-3844
ER -