Background-Cellular transplantation is emerging as a promising strategy for the treatment of postinfarction ventricular dysfunction. Whether its beneficial effects can be extended to other cardiomyopathies remains an unexplored question. We evaluated the histological and functional effects of simultaneous autologous transplantation of co-cultured stem cells and skeletal myoblasts in an experimental model of dilated cardiomyopathy caused by Chagas disease, characterized by diffuse fibrosis and impairment of microcirculation. Methods and Results-Wistar rats weighing 200 grams were infected intraperitoneally with 15ϫ10 4 trypomastigotes. After 8 months, 2-dimensional echocardiographic study was performed for baseline assessment of left ventricle (LV) ejection fraction (EF) (%), left ventricle end-diastolic volume (LVEDV) (mL), and left ventricle end-systolic volume (LVESV) (mL). Animals with LV dysfunction (EF Ͻ37%) were selected for the study. Autologous skeletal myoblasts were isolated from muscle biopsy and mesenchymal stem cells from bone marrow aspirates were co-cultured in vitro for 14 days, yielding a cell viability of Ͼ90%. Eleven animals received autologous transplant of 5.4ϫ10 6 Ϯ8.0ϫ10 6 cells (300 L) into the LV wall. The control group (nϭ10) received culture medium (300 L). Cell types were identified with vimentin and fast myosin. After 4 weeks, ventricular function was reassessed by echo. For histological analysis, heart tissue was stained with hematoxylin and eosin and immunostained for fast myosin.

A comparação entre o transplante de células tronco mononucleares e mesenquimais no infarto do miocárdioComparison of mononuclear and mesenchymal stem cell transplantation in myocardium infarction 271 GUARITA-SOUZA, LC ET AL -Comparison of mononuclear and mesenchymal stem cell transplantation in myocardium infarction Braz J Cardiovasc Surg 2005; 20(3): 270-278Resumo Introdução: O transplante de células no miocárdio tem se mostrado tecnicamente reprodutível, entretanto, existem dúvidas em relação a melhor fração das células da medula óssea a ser utilizada. Desta forma, o objetivo deste estudo é analisar o resultado do transplante de células tronco mononucleares (MO) e mesenquimais (ME) no infarto do miocárdio.Método: Quarenta e dois ratos Wistar foram induzidos ao infarto do miocárdio. Após uma semana, os animais foram submetidos à ecocardiografia para avaliação da fração de ejeção (FE) e dos volumes diastólico (VDFVE) e sistólico (VSFVE) finais do ventrículo esquerdo. Após dois dias, os animais foram reoperados e divididos em grupos: 1) controle (n=21), que recebeu 0,15 ml de meio de cultura, 2) MO (n=8) e 3) ME (n=13), que receberam 3x10 6 células mononucleares e mesenquimais, respectivamente, no infarto. As MO foram obtidas a partir de uma punção da medula e isoladas pelo método Ficoll-Hypaque, as ME, após o mesmo processo, foram

SummaryBackground: The regeneration of cardiomyocytes after a myocardial infarction (MI) is more evident in young animals; however, it is not known whether it is associated with functional improvement.