Abstract 732: Isolation, Expansion and Delivery of Cardiac Derived Stem Cells in a Porcine Model of Myocardial Infarction
Background: Prior research has shown that stem cells can be isolated from adult cardiac tissue, expanded ex vivo, and have beneficial effects in small animal models of myocardial infarction (MI). Translation to humans, however, requires a large animal model. Here we report isolation, expansion, and delivery of cardiac-derived stem cells in a porcine model of MI using standard clinical techniques.
Methods: Infarctions were created in adult miniature swine (n=6) by balloon occlusion of the mid-LAD for 2.5 hours. After reperfusion, tissue was obtained from the right ventricular septum using a bioptome catheter. The biopsies were weighed, enzymatically digested, and placed on fibronectin-coated plates in culture medium. Cells that emerged from the tissue pieces were isolated and then propagated in culture based on their ability to form free-floating multicellular clusters (“cardiospheres”). Cardiosphere-derived cells (CDCs) were transduced with a lentiviral construct encoding nuclear-targeted lacZ. Four weeks after MI/biopsy, pigs received autologous lacZ-labeled CDCs delivered via coronary catheter infusion. Eight weeks later the animals were sacrificed and histological analysis was performed.
Results: The biopsies had an average tissue mass of 91.5 mg (SD +/−54mg) and resulted in a mean cell yield of 14.2 x 106 cells (SD +/−3.1 x 106) after 2.8 cell passages (SD +/−0.8) and 23 days (SD +/−1.6). LacZ transduction was >90% and did not affect cell proliferation potential. X-gal staining of tissue sections showed evidence of cell survival and engraftment in the MI border zone and islands within the scar 8 weeks after coronary delivery.
Conclusions: Cardiac-derived stem cells can be isolated and rapidly expanded from biopsy-sized samples of porcine cardiac tissue. Transduction with lentiviral lacZ is efficient and allows CDC engraftment to be assessed following delivery to the heart. By using standard clinical techniques, this approach provides a model that could be readily adapted to human subjects.