Aims: Intramyocardial and intracoronary stem cell injection has been shown to improve myocardial
function in preclinical and clinical studies. These effects have been desribed in
acute myocardial infarction so far, although the mechanism is still unclear. We investigated
the effects of bone marrow derived stem cells in a porcine model of chronic progressive
myocardial ischemia.
Methods: A circumflex ameroid constrictor was placed off-pump by minimally-invasive surgery
in 11 pigs. Constrictor occlusion was documented angiographically after 2 weeks. At
week 2 and 6, endocardial electromechanical NOGA-system (Biosense Webster, Inc., California,
USA) mapping of the left ventricle, coronary and ventricular angiography, as well
as echocardiography were performed. Two weeks after ameroid placement, 11 pigs were
randomized with 4 pigs receiving mesenchymal or hematopoietic bone marrow dereived
stem cells and 7 pigs receiving placebo at 10 injection sites into the ischemic region
of the myocardium. Injections were performed using a NOGATM guided percutaneous transendocardial
injection catheter, MYOSTARTM. After 6 weeks, histology (Elastica-van-Giesson, Masson's
Trichrome) of ischemic and non-ischemic regions was analyzed.
Results: Endocardial electromechanical mapping showed a significantly reduced ischemic endocardial
surface area compared to the control group (5% vs. 41%) at week 6 suggesting a decline
in ischemia. Morphometric quantitative histological analysis of the ischemic regions
revealed a reduction of myocardial fibrosis (14% vs. 28%) in the stem cell treated
group.
Conclusion: Endocardial stem cell injection may induce cardioprotective effects in hibernating
myocardium and may attenuate the progression of ischemic tissue damage.
