Myocardial repair using stem-cell therapy has become a promising therapeutic tool. However, many questions concerning a precise functional integration of injected cells remain unanswered. The use of cardiac pre-committed cells may improve integration, as these cells may complete their differentiation in the myocardium reducing fibrosis and restoring muscle function. We have previously demonstrated that electrostimulation (ES) induces cardiomyocyte pre-commitment of fibroblasts in vitro and is an effective alternative to cytokine-induced differentiation. In this study, we evaluated the effects of long term electrostimulation on human mesenchymal stem cells (hMSCs). ES induced both morphological and biochemical changes in hMSCs resulting in a shift toward a striated muscle cell phenotype expressing cardiac specific markers. This partially differentiated phenotype might allow a gradual, ongoing differentiation within the cardiac environment, providing time for both myocardial regeneration and electro-mechanical integration, and convey potential advantages in clinical applications.

Ischemic myocardial disease, the main cause of heart failure, is a major public health and economic problem. Given the aging population, heart failure is becoming an increasing clinical issue and a substantial financial burden. Thus, research in heart failure is of relevant interest and importance, involving specialties such as cellular and molecular biology, tissue engineering, genetics, biophysics and electrophysiology. Stem cell-based regenerative therapy is undergoing experimental and clinical trials in order to limit the consequences of decreased contractile function and compliance of damaged ventricles following myocardial infarction or in patients presenting non-ischemic dilated cardiomyopathies. This biological approach is particularly attractive due to the potential for myocardial regeneration with a variety of myogenic and angiogenic cell types. The development of a bio-artificial myocardium using biological or synthetic matrix is a new challenge.

Stem cell therapy is a major field of research worldwide, with increasing clinical application, especially in cardiovascular pathology. However, the best stem cell source and type with optimal safety for functional engraftment remains unclear. An intermediate cardiac precommitted phenotype expressing some of the key proteins of a mature cardiomyocyte would permit better integration into the cardiac environment. The predifferentiated cells would receive signals from the environment, thus achieving gradual and complete differentiation. In cell transplantation, survival and engraftment within the environment of the ischemic myocardium represents a challenge for all types of cells, regardless of their state of differentiation. An alternative strategy is to embed cells in a 3-dimensional structure replicating the extracellular matrix, which is crucial for full tissue restoration and prevention of ventricular remodeling. The clinical translation of cell therapy requires avoidance of potentially harmful drugs and cytokines, and rapid off-the-shelf availability of cells. The combination of predifferentiated cells with a functionalized scaffold, locally releasing molecules tailored to promote in-situ completion of differentiation and improve homing, survival, and function, could be an exciting approach that might circumvent the potential undesired effects of growth factor administration and improve tissue restoration.