Abstract 13644: Functionally Competent Cardiac Stem Cells can be Isolated From Patients Using Endomyocardial Biopsies
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 ischemic heart failure. We sought to develop in vivo, a minimally invasive and reproducible methodology for the isolation and expansion of CSCs from endomyocardial biopsies (EMB) in humans.
In our center, 35 patients with clinically suspected myocarditis (n=20) and/or cardiomyopathy of nonischemic origin including those with infiltrative or connective tissue disease (n=15) underwent either selective LV-EMB (n=26), selective RV-EMB (n=9), or biventricular EMB (n=5) after coronary angiography. Cardiovascular magnetic resonance was performed in all patients. Moreover, EMB were drawn according to intracardiac ecocardiographic imaging and under 3D-electroanatomic guidance (3-EAM).
Samples not used for diagnostic purposes were enzymatically dissociated, and the unfractionated cell population was expanded for 22±4 days. In all patients considered, CSC were successfully isolated. After expansion cells were sorted for c-kit: c-kit positive CSCs were obtained in all patients considered and characterized. At P6, 80% (79±5.3%) of CSCs still expressed 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 27.5±2.2 hours. Additionally at P6, CSC were exposed to a pulse of bromodeoxyuridine 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, 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. 3-EAM guidance may allow to accurately identify low voltage areas corresponding to areas of active inflammation or scar tissue, thus improving safety and harvesting performance even in the setting of non-ischemic cardiomyopathies.
- © 2013 by American Heart Association, Inc.