Hematopoietic stem cells: ex-vivo expansion and therapeutic potential for myocardial ischemia

Despite recent advances in cardiovascular medicine, ischemic heart disease remains the major cause of death in the United States and abroad. Cell-based therapy for degenerative diseases like myocardial ischemia using stem cells is currently under serious investigation. Various types of stem cells are being considered to be candidates for cell transplantation in cell-based therapy. Hematopoietic stem cells are one of the most promising cell types as several studies demonstrated their ability to improve ischemic cardiac functions by enhancing neovascularization and by reducing the total size of scar tissue. However, in order to procure sufficient numbers of functional stem cells, ex-vivo expansion technology became critically important. In this review, we focus on the state-of-the-art ex-vivo technology for the expansion of hematopoietic stem cells, and the underlying mechanisms regulating stem cell self-renewal as well as differentiation.