Stem cell therapies for ischemic heart disease: clinical trial outcomes and futures

Ischemic heart disease carries high morbidity and mortality despite modern pharmaceutical treatment and revascularization procedures. Biologic stem cell therapy offers the potential to revolutionize clinical outcomes for ischemic heart disease by reducing scarring and improving cardiac function. Several small randomized clinical trials have been done utilizing various methodologies, different types of stem cells and doses, and measuring different clinical outcomes. The findings of these individual studies, as well as larger meta-analyses, have been inconsistent likely due to the significant heterogeneity within the methods used. In this review, we provide a more structured approach by comparing the recent studies by type of disease, stem cells, dose, delivery method, and outcome in an effort to draw attention to the similarities and differences in these studies and the need for a standardized approach in larger trials. We show that out of all the current stem cell therapies that have been tried, Adult stem cells, primarily mesenchymal stem cells are currently the most promising for post-myocardial infarction and heart failure while granulocyte colony-stimulating factor and bone marrow mononuclear treatment show efficacy in treating ischemic cardiomyopathy. Lastly, we discuss the potential future directions of stem cell therapy for clinical application in ischemic heart disease.