Analysis of different routes of administration of heterologous 5-azacytidine-treated mesenchymal stem cells in a porcine model of myocardial infarction.

Stem cell therapy constitutes an exciting, powerful therapy to repair the heart. Nevertheless, there are numerous doubts about the best route of stem cell administration to achieve implantation into the injured myocardium. Development of a preclinical, large animal model may be useful to obtain a better approach to clinical situations. The aim of this work was to study the effectiveness of various routes of heterologous bone marrow mesenchymal stem cell (MSCs) administration in a porcine model of myocardial infarction. MSC treated with 5-azacytidine were stained with a fluorescent compound (DiO) before their administration to previously infarcted pigs via 3 routes: intracoronary (IC), intramyocardial (IM), or endocardial (EC; n = 5 each group). Healthy, noninfarcted animals were used as a control group. At 30 days after delivery, hearts were divided into 12 parts: infarcted zone (1-6), right-left atria, interatrial and interventricular septa, and right-left ventricles. In each zone we looked for and quantified, injected fluorescence-stained cells. In the animals in which presence of DiO-stained cells was detected, cells were located preferentially in the infarcted zone and not in the atria, ventricles, or septa. Comparing various administration routes, the mean number of engrafted cells within the infarct zone was significantly greater after IC infusion than either IM or EC injection. Fluorescent cells were not observed in healthy zones of the myocardium or in healthy animals.

Gene expression profiles in a porcine model of infarction: differential expression after intracoronary injection of heterologous bone marrow mesenchymal cells.

Myocardial infarction is one of the main causes of mortality in developed countries. Injection of bone marrow mesenchymal stem cells (BMMSC) with the ability to regenerate lost cardiomyocytes is a promising therapy for heart failure. To evaluate this strategy, an in vivo porcine model of infarction was used. Gene expression profiles of 3 groups of pigs (n = 5 each) were analyzed and compared by real-time reverse transcription-polymerase chain reaction (RT-PCR). One of the groups underwent anterior descending coronary occlusion followed by BMMSC injection; a placebo group was injected with culture medium without cells after infarction; and a third group was formed by healthy pigs. Four weeks later, cells or medium was administered by intracoronary injection and, a month later, animals were sacrificed and samples collected. Genes related to cardiomyogenesis (Mef2C, Gata4, Nkx2.5), mobilization and homing of resident or circulating stem cells (Sdf1, Cxcr4, c-Kit), contractibility (Serca2a), and fibrosis (CollA1) were analyzed. Gene expression profiles changed in various heart areas in the 3 groups. Expression of genes related to cardiomyogenesis decreased in infarcted zones compared with homologous regions of healthy hearts. Sdf1 expression increased in the apex of infarcted hearts. Serca2a expression was reduced in the ventricles and atria of infarcted hearts. Also, increases in Cxcr4 and CollA1 expression were observed in infarcted hearts of cell-treated pigs compared with the placebo group. In conclusion, infarction induced changes in genes involved in various biological processes. Intracoronary injection of heterologous BMMSC resulted in localized changes in the expression of Cxcr4 and Col1A1.