Author(s): Yijen L. Wu, Qing Ye, Lesley M. Foley, T. Kevin Hitchens, Kazuya Sato, John B. Williams, and Chien Ho

Pittsburgh NMR Center for Biomedical Research, Department of Biological Sciences, Carnegie Mellon University

Title: In situ labeling of immune cells with iron oxide particles: An approach to detect organ rejection by cellular MRI

Summary: In vivo cell tracking by MRI can provide means to observe biological processes and monitor cell therapy directly. Immune cells, e.g., macrophages, play crucial roles in many pathophysiological processes, including organ rejection, inflammation, autoimmune diseases, cancer, atherosclerotic plaque formation, numerous neurological disorders, etc. The current gold standard for diagnosing and staging rejection after organ transplantation is biopsy, which is not only invasive, but also prone to sampling errors. Here, we report a noninvasive approach using MRI to detect graft rejection after solid organ transplantation. In addition, we present the feasibility of imaging individual macrophages in vivo by MRI in a rodent heterotopic working-heart transplantation model using a more sensitive contrast agent, the micrometer-sized paramagnetic iron oxide particle, as a methodology to detect acute cardiac rejection.

Source: Proceedings of the National Academy of Sciences 103: 1852-1857, 2006.