Using Hyperpolarized [1-13C]Pyruvate as a Dynamic Marker for Intracellular PH

Marie Allen Schroeder¹, Helen J. Atherton¹, Lisa C. Heather¹, Mark Aaron Cole¹, Kieran Clarke¹, George K. Radda¹, Damian J. Tyler¹

As decreased pH is characteristic of myocardial ischaemia, the ability to dynamically monitor cardiac pH may be clinically important. This study assessed the validity of using hyperpolarized [1-¹³C]pyruvate, specifically the H¹³CO₃^-/¹³CO₂ ratio, as a marker of intracellular pH in the isolated perfused heart. Intracellular ¹³C pH measurements made in healthy hearts, with 1 s temporal resolution, were validated using steady-state ³¹P MR spectroscopy (MRS). Additionally, pH equilibration showed distinct kinetic trends in healthy and post-ischaemic hearts. These results have indicated that H¹³CO₃^-/¹³CO₂ could be a useful parameter to monitor alterations to cardiac metabolism that occur due to ischaemic heart disease.