Current status of intramyocardial bone marrow stem cell transplantation.

Since the first reports of the capacity of bone marrow stem cells for use in cardiac repair and regeneration after acute myocardial infarction, today, the therapeutic strategy of direct cell administration during cardiac surgery is entering clinical practice. Here we report on the current knowledge of the "new cellular tool" in the cardiac surgeon's hands that is enabling them to exceed the limits of modern methods for myocardial revascularization and repair in cardiac surgery. Therefore, we discuss preclinical data focusing on bone marrow stem cell types and point to the current mechanistic explanation of their effects. With 7 years' experience after completing Phase I and Phase II clinical trials with cardiac transplantation of autologous intramyocardial bone marrow stem cells, we draw conclusions about surgical applicability, safety, and efficacy. At present, the functional effects of this treatment are highly promising to become a standard treatment. Further clarification by prospective randomized clinical Phase III trials is necessary in this field.