Non-surgical stem cell delivery strategies and in vivo cell tracking to injured myocardium.

Heart failure is a major economic and public health problem. Despite the recent advances in drug therapy and coronary revascularization, the lost cardiomyocytes due to necrosis and apoptosis are not replaced by new myocardial tissue. Cell therapy is an interesting therapeutic option as it potentially improves contractility and restores regional ventricular function. Early clinical data demonstrated that cell transplantation, mainly delivered through non-surgical methods, is safe and feasible. However, several important issues need to be elucidated. This includes, next to determining the best cell type, the optimal delivery strategy, the biodistribution and the survival of implanted stem cells after transplantation. In this view, pre-clinical animal experiments are indispensable. Reporter genes, magnetic or radioactive labeling of stem cells have been developed to observe the fate and the distribution of transplanted cells using non-invasive imaging techniques. Several studies have demonstrated that these direct and non-direct labeling techniques may become an important tool in cell therapy. Integration of cell delivery and cell tracking will probably be a key for the success of cell therapy in patients. This review will provide a comprehensive overview on the various cell tracking and non-surgical cell delivery techniques, which are highly important in view of experimental and clinical studies.