Cardiac FDG-PET: a straight forward tool with high potential.

The latter component is based on the fact that homing into ischaemic tissue is mediated by stromal cell-derived factor (SDF)-1 expression in the myocardium which binds to its corresponding receptor CXCR-4 on circulating stem cells. SDF-1 is usually inactivated by enzymatic cleavage via dipeptidyl peptidase IV (DPP-IV). Hence, pharmacological inhibition of DPP-IV stabilizes SDF-1 and enhances stem cell homing into ischaemic myocardium. Brunner’s group has shown that combined treatment of AMI in mice with G-CSF and sitagliptin leads to a significant increase in both survival and cardiac function. These beneficial effects were attributed to increased cardiac homing of bone marrow-derived stem cells which induced neovascularization and reduced cardiac remodelling as well as apoptosis. The study of Gross et al. was now performed to substantiate the possible effects of this therapeutic concept on cardiac remodelling after AMI by use of 18F-FDG-based micro-PET. Therefore, 13 mice were treated for 5 days with G-CSF and sitagliptin (GS) after surgical AMI induction according to a previously established protocol. Ten mice receiving saline (placebo) after AMI induction served as control. On Day 6 and Day 30 after AMI induction, the animals were anaesthetized with isoflurane, and FDG-PET scans were acquired in a dedicated small animal PET scanner. Analysis of these images revealed the following: