Abstract 17086: Cardiac Stem Cells Can Be Isolated and Characterized from 3D-Electroanatomic Guided Endomyocardial Biopsies in a Preclinical Animal Model
Intracoronary infusion of Cardiac Stem Cells (CSCs) isolated from right atrial appendage, resected during CABG is effective in improving left ventricular systolic function and reducing infarct size in patients with heart failure. Utilizing a porcine model, we sought to develop in vivo, a minimally invasive and reproducible methodology for the isolation and expansion of CSCs from endomyocardial biopsies (EMB). Via right femoral vein in healthy mini pigs, EMB (4 to 6 samples per animal yielding a total sample weight of 12.8±3.0 mg) were drawn using a preformed sheath and a disposable bioptome from right ventricular endocardium. EMB were performed under 3D-electroanatomic guidance (3-EAM) and according to intracardiac ecocardiographic imaging. Biopsies from each animal were enzymatically dissociated, and the unfractionated cell population was expanded for 15±3 days. After expansion cells were sorted for c-kit: c-kit positive CSCs were obtained in all 8 pigs considered and characterized. At P6 more than 90% (92±4.3%) of CSCs still express c-kit in culture and were negative for markers of hematopoietic and mesenchymal lineage. Only a small fraction of CSCs were positive for markers of myocyte, endothelial or smooth muscle cell lineage. Population doubling time was calculated and averaged 26.5±3.2 hours. Additionally at P6, CSC were exposed to a pulse of bromodeoxyuridine (BrdU) and analyzed 12 hours later: 8.1±1.3% CSC were positive for BrdU. Telomere length was measured in CSCs by flow-FISH: telomeres varied from 6.3 to 7.8 kbp, far from telomere lengths associated with replicative senescence and growth arrest. Consistently, at the same passage in culture, only 2.1±1.3% of CSCs were positive for p16INK4a. In the present study, we established the conditions for the isolation and expansion of c-kit-positive CSCs from EMB in vivo. Additionally, 3-EAM guidance may allow to accurately identify and locate low voltage areas corresponding to areas of active inflammation or scar tissue, thus improving harvesting performance in the setting of non-ischemic cardiomyopathies and avoiding to draw samples from scar regions in case of ischemic cardiomyopathies and therefore increasing the safety profile of the procedure and enhancing the regenerative potential of CSCs.
- © 2012 by American Heart Association, Inc.