Limitations to the Assessment of Reperfusion Injury With Radiolabeled 2-Deoxyglucose

To the Editor: Matsumura et al1 propose a new method to determine reperfusion injury in dog heart. The phosphorylation rate constant, k 3, for two 2-deoxyglucose moieties ([14C]2-DG and 18F-2-deoxy-2-fluro-D-glucose [FDG]) was compared with histological assessment of ischemic damage. The results suggest that a large portion of the infarcted myocardium loses viability during the first hours of reperfusion. If true, this would be the first demonstration of a bimodal time course of reperfusion injury in vivo.Two factors may have affected the interpretation of the results. First, the assumption is made that the total 14C radioactivity in each sample is proportional to the phosphorylation rate. However, the contribution of unphosphorylated deoxyglucose, although declining, is never negligible, and in some circumstances, it can represent the majority of the tissue radioactivity. Correction for this is the main supposition of the deoxyglucose method.2 Neglecting this correction is particularly problematic because the relationship between phosphorylated and unphosphorylated deoxyglucose concentrations …