ABSTRACT
Despite recent advances in pharmacological and interventional therapies, cardiovascular diseases remain the leading causes of morbidity and mortality worldwide. Stem cells are undifferentiated cells characterized by their functional capacity to self-renew and to generate a large number of differentiated progeny cells. Recently, stem cell transplantation has been investigated as a potential novel therapeutic approach in patients with myocardial infarction and heart failure (Siu et al. 2010). One of the major challenges in cardiac stem cell therapy is cell engraftment and survival after transplantation. In vivo experimental studies have demonstrated the feasibility of monitoring cell migration and cell fate after transplantation using either reporter genes or chimeric animals (Cahill et al. 2004). However, these methods are cumbersome and cannot be translated to human use. Besides, this approach lacks the temporal analysis of the donor cells and limits its practical use. Thus, methods for monitoring implanted stem cell non-invasively in vivo will greatly facilitate the clinical realization and optimization of cell-based therapies. Cellular imaging can permit non-invasive visualization of cellular processes, including cell migration, and sequential fate and effi cacy in tissue regeneration and maintenance, in living subjects. Unfortunately, there is a very limited method to allow serial monitoring of stem cells in clinic after transplantation (Ransohoff and Wu 2010). The recent development of superparamagnetic iron oxide (SPIO) nanoparticles labeling and cardiac magnetic resonance imaging (MRI) may provide a powerful tool to allow non-invasive tracking of cell migration and survival after transplantation. Nevertheless, the feasibility, effi ciency and safety issues of this method should be addressed before clinical applications.
