Intramuscular Transplantation of Pig Amniotic Fluid-Derived Progenitor Cells Has Therapeutic Potential in a Mouse Model of Myocardial Infarction

Acute myocardial infarction (MI) is a fatal event that causes a large number of deaths worldwide. MI results in pathological remodeling and decreased cardiac function, which could lead to heart failure and fatal arrhythmia. Cell therapy is a potential strategy to repair the damage through enhanced angiogenesis or by modulation of the inflammatory process via paracrine signaling. Amniotic fluid-derived progenitor cells (AFPCs) have been reported to differentiate into several lineages and can be used without ethical concerns or risk of teratoma for-mation. Since pigs are anatomically, physiologically, and genetically similar to humans, and pregnant pigs can be an abundant source of AFPCs, we used porcine AFPCs (pAFPCs) as our target cells. Intramyocardial injection of AFPCs has been shown to cure MI in animal models. However, intramuscular transplantation of cells has not been extensively investigated. In this study, we investigated the therapeutic potential of intramuscular injection of pAFPCs on acute MI. MI mice were divided into 1) PBS control, 2) medium cell dose (1 × 10⁶ cells per leg; cell-M), and 3) high cell dose (4 × 10⁶ cells per leg; cell-H) groups. Cells or PBS were directly injected into the hamstring muscle 20 min after MI surgery. Four weeks after MI surgery, the cell-M and cell-H groups exhibited significantly better ejection fraction, significantly greater wall thickness, smaller infarct scar sizes, and lower LV expansion index compared to the PBS group. Using in vivo imaging, we showed that the hamstring muscles from animals in the cell-M and cell-H groups had RFP-positive signals. In summary, intramuscular injection of porcine AFPCs reduced scar size, reduced pathological remodeling, and preserved heart function after MI.