Stem cells harvested at birth from a patient’s umbilical cord could be stored and then reintroduced in the patient at a later date, therapy taking advantage of the immaturity and vitality of the "infant" cells and avoiding the complications of allograft transplant rejection. A potential new therapeutic approach is to increase the functions myocytes within an area of infracted myocardium by implantation of myogenic cells. Fetal cardiomyocytes introduced into animals have been shown to survive and differentiate in infracted tissue improving cardiac performance.
Umbilical cord blood stem cells were recently shown to have a vascular endothelial grown factor receptor on their cell surfaces, suggesting that they may be able to differentiate into progenitor endothelial cells of possibly even cardiac cells. Endothelial cell progenitors have also been isolated from human peripheral blood and may be useful for augmenting collateral vessel growth to ischemic tissues and instituting therapeutic angiogenesis. Bone marrow stem cells are also being explored for their potential ability to regenerate infracted myocardium. Locally derived bone marrow cells have the ability to generate de novo myocardium, potentially ameliorating the outcome of coronary artery disease. In addition, neovascularization was observed. This new form of repair could improve the immediate and long-term outcome of ischemic heart disease. Injection of bone marrow stem cells has been shown in animals to improve regional blood flow and cardiac function. In mice, bone marrow stem cells migrated to the site of ischemic damage and then differentiated into cardiomyocytes and endothelial cells that contributed to the formation of functional tissue. These findings support the development diversity of hematopoletic stem cells and suggest that their functional role may be largely determined by their microenvironment.