title: Hyperpolarized 13C dehydroascorbate as an endogenous redox sensor for in vivo metabolic imaging.
abstract: Reduction and oxidation (redox) chemistry is involved in both normal and abnormal cellular function, in processes as diverse as circadian rhythms and neurotransmission. Intracellular redox is maintained by coupled reactions involving NADPH, glutathione (GSH), and vitamin C, as well as their corresponding oxidized counterparts. In addition to functioning as enzyme cofactors, these reducing agents have a critical role in dealing with reactive oxygen species (ROS), the toxic products of oxidative metabolism seen as culprits in aging, neurodegenerative disease, and ischemia/ reperfusion injury. Despite this strong relationship between redox and human disease, methods to interrogate a redox pair in vivo are limited. Here we report the development of [1-(13)C] dehydroascorbate [DHA], the oxidized form of Vitamin C, as an endogenous redox sensor for in vivo imaging using hyperpolarized (13)C spectroscopy. In murine models, hyperpolarized [1-(13)C] DHA was rapidly converted to [1-(13)C] vitamin C within the liver, kidneys, and brain, as well as within tumor in a transgenic prostate cancer mouse. This result is consistent with what has been previously described for the DHA/Vitamin C redox pair, and points to a role for hyperpolarized [1-(13)C] DHA in characterizing the concentrations of key intracellular reducing agents, including GSH. More broadly, these findings suggest a prognostic role for this new redox sensor in determining vulnerability of both normal and abnormal tissues to ROS.
authors: Department of Radiology and Biomedical Imaging, University of California San Francisco, 1700 4th Street, Byers Hall 203, San Francisco, CA 94158, USA.
authors: Kayvan R
authors: KR
authors: Keshari
authors: John
authors: J
authors: Kurhanewicz
authors: Robert
authors: R
authors: Bok
authors: Peder E Z
authors: PE
authors: Larson
authors: Daniel B
authors: DB
authors: Vigneron
authors: David M
authors: DM
authors: Wilson
mesh_terms: D000818:Animals; D016880:Anisotropy; D001205:Ascorbic Acid / Q000737:chemistry / Q000378:metabolism; D001921:Brain / Q000378:metabolism; D002247:Carbon Isotopes / Q000737:chemistry*; D003683:Dehydroascorbic Acid / Q000737:chemistry*; D005978:Glutathione / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D007700:Kinetics; D008099:Liver / Q000378:metabolism; D008279:Magnetic Resonance Imaging / Q000379:methods; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D051379:Mice; D009369:Neoplasms / Q000378:metabolism; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species; D014018:Tissue Distribution
chemical_list: D002247:Carbon Isotopes; D017382:Reactive Oxygen Species; D005978:Glutathione; D001205:Ascorbic Acid; D003683:Dehydroascorbic Acid