Origin and Selection of Stem Cells for Cardiac Repair after Myocardial Infarction

Despite state-of-the-art methods for the early diagnosis and treatment, heart failure resulting from myocardial infarction (MI) continues to be a major cause of morbidity and mortality worldwide. Most of the existing treatment modalities against heart failure are symptom-based, short-term and do not prolong survival. Stem cell-based therapy is promising strategy to lead to cardiac repair after MI. Over the last decade, stem cells with diverse origin, identity, and plasticity have been utilized for the regeneration and repair of damaged myocardium after MI, both in animal models and humans. The major challenges and dilemmas in stem cell therapy after MI included-ethical concerns and alloreactivity (with embryonic stem cells), malignant transformation and vector contamination (with inducible progenitor cells), coronary restenosis (with mobilization of bone marrow stem cells), and cardiac arrhythmias and structural heterogeneity due to non-coupling of cardiac and non-cardiac skeletal cells (with skeletal myoblasts). Therefore, as much as the progress made in the field of cardiac regenerative therapy, questions have been asked on what constitutes the most appropriate source for the stem cells. In particular, the identity, characteristics and ability of the stem cells to retain their fate while being propagated ex vivo have invited a passionate discussion among cell-biologists, geneticists and clinicians. This review summarizes the diverse origin of the stem cells and discusses recent advances made for the identification, selection and propagation of stem cells for the regeneration or repair of damaged myocardium after MI.