Cells to repair the infarcted myocardium

The adult mammalian heart has poor regenerative capacity. Loss of functional cardiomyocytes following myocardial infarction leads to the replacement of functional muscle by scar tissue. This has a detrimental effect on cardiac function and may lead to heart failure. Potential regeneration of severe cardiac damage would require replacement of dead and damaged cardiomyocytes by transplantation, recruitment of endogenous progenitor cells, or induction of cardiomyocyte proliferation. For more than a decade, clinical trials to ameliorate the injured heart have been under way. However, after evaluation of the outcome of these trials it is evident that the beneficial effects of these cell-based transplantations are only marginal, and beneficial effects, if any, are not caused by regeneration of cardiomyocytes. In recent years, alternative approaches and various cell sources have been studied and suggested for cardiac repair. Recent advances in these cell-based therapies or strategies to activate endogenous cardiac repair are discussed.

Stem Cell Therapy Post-AMI

• Experimental studies suggest that bone marrow-derived stem cells can improve function of infarcted myocardium• This benefit seems to involve paracrine signalling and limitation of left ventricular remodelling rather than true regeneration of cardiomyocytes from donor cells• These experimental findings have been translated in the clinical setting into significant, although moderate, improvements in cardiac function and LV remodelling but the extent to which these benefits impact on event-free long term survival remains to be determined• Optimisation of this therapeutic strategy will require a more comprehensive characterisation of cell functionality and an improvement in the methods used in cell transfer, engraftment, survival and integration.