13C MR Hyperpolarization of Lactate by Using ParaHydrogen and Metabolic Transformation in Vitro

Hyperpolarization of the 13C magnetic resonance signal of L-[1-13C]Lactate has been obtained using the chemically based, cost-effective method named ParaHydrogen Induced Polarization by means of Side Arm Hydrogenation (PHIP-SAH). Two ester derivatives of lactate have been tested and the factors that determine the polarization level on the product have been investigated into details. The metabolic conversion of hyperpolarized L-[1-13C]Lactate into Pyruvate has been observed in vitro using lactate dehydrogenase (LDH) and in a cells lysate. From the acquisition of a series of 13C-NMR spectra, the metabolic build-up of the [1-13C]Pyruvate signal has been observed. These studies demonstrate that, even if the experimental set-up used for these PHIP-SAH hyperpolarization studies is still far from optimal, the attained polarization level is already sufficient to carry out in vitro metabolic studies.