Repeated implantation of skeletal myoblast in a swine model of chronic myocardial infarction

Aims Although transplantation of skeletal myoblast (SkM) in models of chronic myocardial infarction (MI) induces an improvement in cardiac function, the limited engraftment remains a major limitation. We analyse in a pre-clinical model whether the sequential transplantation of autologous SkM by percutaneous delivery was associated with increased cell engraftment and functional benefit. Methods and results Chronically infarcted Goettingen minipigs (n = 20) were divided in four groups that received either media control or one, two, or three doses of SkM (mean of 329.6 x 10(6) cells per dose) at intervals of 6 weeks and were followed for a total of 7 months. At the time of sacrifice, cardiac function was significantly better in animals treated with SkM in comparison with the control group. A significantly greater increase in the Delta LVEF was detected in animals that received three doses vs. a single dose of SkM. A correlation between the total number of transplanted cells and the improvement in LVEF and Delta LVEF was found (P < 0.05). Skeletal myoblast transplant was associated with an increase in tissue vasculogenesis and decreased fibrosis (collagen vascular fraction) and these effects were greater in animals receiving three doses of cells. Conclusion Repeated injection of SkM in a model of chronic MI is feasible and safe and induces a significant improvement in cardiac function.