In vivo Metabolic Sensing of Hyperpolarized [1-¹³C]Pyruvate in Mice Using a Recyclable Perfluorinated Iridium Signal Amplification by Reversible Exchange Catalyst

Real-time visualization of metabolic processes in vivo provides crucial insights into conditions like cancer and metabolic disorders. Metabolic magnetic resonance imaging (MRI), by amplifying the signal of pyruvate molecules through hyperpolarization, enables non-invasive monitoring of metabolic fluxes, aiding in understanding disease progression and treatment response. Signal Amplification By Reversible Exchange (SABRE) presents a simpler, cost-effective alternative to dissolution dynamic nuclear polarization, eliminating the need for expensive equipment and complex procedures. We present the first in vivo demonstration of metabolic sensing in a human pancreatic cancer xenograft model compared to healthy mice. A novel perfluorinated Iridium SABRE catalyst in a fluorinated solvent and methanol blend facilitated this breakthrough with a 1.2-fold increase in [1-¹³C]pyruvate SABRE hyperpolarization. The perfluorinated moiety allowed easy separation of the heavy-metal-containing catalyst from the hyperpolarized [1-¹³C]pyruvate target. The perfluorinated catalyst exhibited recyclability, maintaining SABRE-SHEATH activity through subsequent hyperpolarization cycles with minimal activity loss after the initial two cycles. Remarkably, the catalyst retained activity for at least 10 cycles, with a 3.3-fold decrease in hyperpolarization potency. This proof-of-concept study encourages wider adoption of SABRE hyperpolarized [1-¹³C]pyruvate MR for studying in vivo metabolism, aiding in diagnosing stages and monitoring treatment responses in cancer and other diseases.