Preservation of left ventricular function and attenuation of remodeling after transplantation of human epicardium-derived cells into the infarcted mouse heart.

BACKGROUND: Proper development of compact myocardium, coronary vessels, and Purkinje fibers depends on the presence of epicardium-derived cells (EPDCs) in embryonic myocardium. We hypothesized that adult human EPDCs might partly reactivate their embryonic program when transplanted into ischemic myocardium and improve cardiac performance after myocardial infarction. METHODS AND RESULTS: EPDCs were isolated from human adult atrial tissue. Myocardial infarction was created in immunodeficient mice, followed by intramyocardial injection of 4x10(5) enhanced green fluorescent protein-labeled EPDCs (2-week survival, n=22; 6-week survival, n=15) or culture medium (n=24 and n=18, respectively). Left ventricular function was assessed with a 9.4T animal MRI unit. Ejection fraction was similar between groups on day 2 but was significantly higher in the EPDC-injected group at 2 weeks (short term), as well as after long-term survival at 6 weeks. End-systolic and end-diastolic volumes were significantly smaller in the EPDC-injected group than in the medium-injected group at all ages evaluated. At 2 weeks, vascularization was significantly increased in the EPDC-treated group, as was wall thickness, a development that might be explained by augmented DNA-damage repair activity in the infarcted area. Immunohistochemical analysis showed massive engraftment of injected EPDCs at 2 weeks, with expression of alpha-smooth muscle actin, von Willebrand factor, sarcoplasmic reticulum Ca2+-ATPase, and voltage-gated sodium channel (alpha-subunit; SCN5a). EPDCs were negative for cardiomyocyte markers. At 6-weeks survival, wall thickness was still increased, but only a few EPDCs could be detected. CONCLUSIONS: After transplantation into ischemic myocardium, adult human EPDCs preserve cardiac function and attenuate ventricular remodeling. Autologous human EPDCs are promising candidates for clinical application in infarcted hearts.

Genetic programme of cardiogenesis: implications for therapeutic application.

It has become accepted that new cardiomyocytes can be derived from stem cells. Although the potential for therapeutic application is evident, the reported efficiency of differentiation varies greatly from 0.02 to 54%. To obtain clinically relevant numbers of newly differentiated cardiac cells, stem cell differentiation should be as efficient as possible. A plausible way to increase the efficiency of differentiation of stem cells into cardiomyocytes is through the introduction of cardiac specific regulatory genes in the stem cells. This review summarises the role of several key transcription factors in cardiogenesis.