Preparation of Magnetically Labeled Cells for Cell Tracking by Magnetic Resonance Imaging

This chapter describes the preparation of magnetically labeled cells for cell tracking by magnetic resonance imaging (MRI). Magnetic resonance (MR) tracking of magnetically labeled cells following transplantation or transfusion is a rapidly evolving new field. At one hand, MR cell tracking with its excellent spatial resolution can be used as a noninvasive tool to provide unique information on the dynamics of cell movement within and from tissues in animal disease models. As for MR contrast agents, gadolinium is the most effective paramagnetic contrast agent, owing to its seven unpaired electrons, but its relaxivity is far lower than the so-called superparamagnetic iron oxides. A significant improvement of labeling of nonphagocytic cells has been achieved by linking the particles to the human immunodeficiency virus (HIV) tat peptide. The distribution of magnetic microsphere-labeled porcine mesenchymal stem cells has been studied in a swine myocardial infarct model using MRI. Control cells are run side-by-side to determine the percent increased reactive oxygen species (ROS) production in the labeled cells. A transient increase in ROS production is also observed for the labeled cells.