Cell therapy in myocardial infarction: emphasis on the role of MRI.

Despite tremendous progress in myocardial infarct (MI) treatment, mortality rates remain substantial. Permanent loss of cardiomyocytes after ischemic injury, results in irreversible loss of myocardial contractility, reduction in ventricular performance, and may initiate the development of dilated heart failure. The discovery that pluripotent progenitor cells bear the capacity to differentiate to mature cardiac cells raised the hope of cell-based regenerative medicine. Engraftment of stem cells in the damaged myocardium, repair and functional improvement appeared suddenly a nearby reality. Promising results in animal models, and preliminary studies reporting the feasibility and safety of adult stem cell therapy in MI patients led to the first double-blinded randomized, placebo-controlled trials. The initial great enthusiasm for this paradigm shift in MI treatment has been tempered by the mainly negative or modestly positive study findings. Before new, larger clinical trials can be initiated, a number of critical questions and issues need to be considered starting with a scrutinized analysis of currently available data to extending our knowledge of the mechanism of scarless myocardial regeneration. Cardiac cell therapy necessitates a multidisciplinary approach, whereby imaging, in particular MRI, and the input of the imaging specialist is crucial to the success of cardiac cell regenerative medicine. MRI is an appealing technique for cell trafficking depicting engraftment, differentiation and survival. Endomyocardial cell administration can be achieved safely with MR fluoroscopy and MRI is without any doubt the most accurate and reproducible technique to measure study end-points.