Does stem cell therapy induce myocardial neoangiogenesis? Histological evaluation in an ischemia/reperfusion animal model

Background: In an experimental model in the rabbit, a myocardial ischemia-reperfusion injury was obtained. Subsequently, the effects of homologous bone marrow stem cell (BMSC) administration were studied. Methods: In 21 New Zealand adult rabbits, ischemia/reperfusion damage was induced by temporary occlusion of the anterior descending coronary artery. Homologous BMSCs were isolated, cultured and re-suspended for injection at the level of the ischemic zone. We evaluated the proangiogenetic effect of intramyocardial injections of BMSC at the peri-infarcted area. Histological evaluations were made after 20 days from the surgical procedure. Results: In rabbits treated with intramyocardial BMSC administration, we demonstrated histologically capillary neoangiogenesis, without signs of tissue immunological reaction or of generation of new myocardial cells. On the contrary, only minimal neovascular supply was detected in rabbits treated with intravenous administration of BMSC. Only typical signs of ischemic myocardium injury were observed in the control group. Conclusion: These observations suggest that the effect of direct BMSC administration in ischemic myocardium could promote a capillary neoangiogenesis, which helps to prevent ischemic myocardial damage.