Differentiation of resident stem cell population improves cardiac function

The quest to regenerate functional myocardium from stem cells following myocardial infarction has garnered a great deal of media attention and has become something of a holy grail in cardiovascular medicine. Despite the basic science of stem cells still being at an early stage, the first human trials have already been conducted—but the results thus far have been neutral at best with little or no evidence of clinical benefit. A significant bottleneck is the identification of a viable source of stem/progenitor cells that could contribute new muscle with the therapeutic ideal being to stimulate a resident source, thus avoiding the caveats of limited graft survival, restricted homing to the site of injury and host immune rejection.

In contrast to the bone-marrow-derived cells that have been generally used thus far, the authors of this study, which was performed in various experimental mouse models, demonstrate that the adult heart contains a resident stem or progenitor cell population, which has the potential to contribute bona fide terminally differentiated cardiomyocytes after myocardial infarction. By priming these cells with a peptide called thymosin β4, they were able to induce embryonic reprogramming, resulting in the mobilisation of this population and subsequent differentiation to give rise to de novo cardiomyocytes. Following experimentally induced myocardial infarction, these cells were shown to migrate to the site of injury and then differentiate without any evidence of cellular …