Drawbacks to stem cell therapy in cardiovascular diseases.

Stem cells seem to have unlimited potential for repairing injured tissues derived from cardiovascular diseases. Much as the initial euphoria over preclinical models has ushered in some skepticism, several reports have advised caution against over exuberance, as cellular therapy has both theoretical and reported safety concerns. Embryonic stem cells, skeletal myoblasts, bone marrow-derived stem cells and mesenchymal stem cells are current candidates for cell therapy in end-stage cardiovascular diseases. However, before large-scale clinical trials can take place, a few safety concerns have to be clarified, such as atherogenesis, postangioplasty or stenting restenosis, tumorigenesis, stem cell metastasis, stem cell-mobilized cytokine-related complications and arrhythmogenesis. In this review, potential ways to overcome these issues are discussed, including medical and gene manipulations, dedicated cell-purification techniques, antiarrhythmic cell therapy design, and new concepts such as using natural constructs. With these safety issues under control, stem cell therapy still has a promising future in the next decade.