Non-invasive In-Vivo Imaging of Stem Cells after Transplantation in Cardiovascular Tissue

Stem cell therapy for degenerative diseases, including ischemic heart disease is now a clinical reality. In the search for the optimal cell type for each patient category, many different stem cell subpopulations have been used. In addition, different cell processing procedures and delivery methods have been utilized. Moreover, choices of endpoints have varied between studies. Diverging results have been reported from clinical experiences, with some studies demonstrating promising results with improved cardiac function and reduced mortality and clinical symptoms, and others have seen no improvements. To better understand the underlying mechanisms of these results, a reverse translation from bedside to bench has been opened. Non-invasive cell tracking after implantation has a pivotal role in this translation. Imaging based methods can help elucidate important issues such as retention, migration and efficacy of the transplanted cells. Great effort is being made in finding new and better imaging techniques for different imaging modalities, and much have already been learned. But there are still many unanswered questions. In this review, we give an overview of the imaging modalities used for cell tracking and summarize the latest advances within the field.