Abstract 15620: Persistence and Survival of Rat Neonatal Cardiomyocytes after Injection into Infarcted Syngeneic Hearts Depends on their Purity and Is Improved by Co-Injection of Mesenchymal Bone-Marrow Cells
Purpose: For the effectiveness of cardiac cell replacement therapy, the number of persisting new contractile cells within the injured heart is crucial. In previous studies we found that persistence and survival of highly purified cardiomyocytes (CM) derived from embryonic stem (ES) or induced pluripotent stem (iPS) cells was markedly lower than that of moderately purified isolated fetal or neonatal CM. Besides cell specific differences, CM purity might affect persistence and survival which was therefore investigated in this study.
Methods: In adult female Fischer344-rats, myocardial infarction (MI) was induced by coronary ligation, and isolated syngeneic male neonatal CM were injected (in 100µl). Prior to transplantation, CM were purified by Percoll gradient centrifugation or a preplating episode of 30 min., resulting in approx. 80% (Percoll 80%-CM, n=9) and 60% (pre-plated 60%-CM, n=12) CM-purity, respectively (immunofluorescence). In additional groups, the purity of Percoll purified CM was intentionally reduced to 60% by adding syngeneic female neonatal cardiac fibroblasts (+fFB 60%-CM, n=6) or mesenchymal bone-marrow cells (+fMSC 60%-CM, n=6). Hearts were excised after 3 weeks and persistence of transplanted CM was determined with quantitative real-time PCR for Y-chromosomes.
Results: 3 weeks after MI and intramyocardial injection of 5 million Percoll 80%-CM, 92,477±18,658 male cells or 1.8±0.4% of the injected male cell number were detected. Numbers were higher for 5 million pre-plated 60%-CM with 263,841±63,639 or 5.3±1.3% (p=0.04). Interestingly, the similarly pure +fFB 60%-CM yielded similar numbers with 227,454±63,165 or 6.1±1.7%. In contrast, admixture of female mesenchymal bone-marrow cells in +fMSC 60%-CM significantly increased numbers to 471,322±168,589 (p<0.05 vs. Percoll 80%-CM) or 12.6±4.5% (p<0.01 vs. Percoll 80%-CM).
Conclusions: Our data suggest that persistence and survival of cardiomyocytes after injection into infarcted syngeneic hearts depends on their purity. The crucial role of non-CM for successful cell therapy requires further exploration, especially as the co-injection of mesenchymal bone-marrow cells seems to be beneficial.
- Stem cell therapy
- Regenerative medicine stem cells
- Cardiac regeneration
- Cardiac injection
- Stem cell biology
- © 2011 by American Heart Association, Inc.