Abstract 16082: Reversal of Ischemic Cardiomyopathy With Sca1+ Stem Cell Genetically Modified for Multiple Therapeutic Growth Factors Expression
Background: We hypothesized that a combined approach involving Sca1+ bone marrow stem cells as carriers of multiple therapeutic genes will be more effective in preservation of heart function after ischemic injury by paracrine release of therapeutic growth factors and myoangiogenic differentiation of stem cells.
Methods and Results: Sca1+ bone marrow stem cells were purified from transgenic male mice expressing GFP. Plasmids encoding for select quartet of growth factors, i.e., human IGF1, VEGF, SDF1 and HGF were prepared and used for genetic modification of Sca1+ cells (GFSca-1+). Scramble transfected cells (ScSca-1+) were used as a control. RT-PCR and Western blotting showed significantly higher expression of the growth factors in GFSca-1+. Besides the quartet of the therapeutic growth factors, PCR based growth factor array showed upregulation of multiple angiogenic and prosurvival factors such as Ang-1, Ang-2, MMP9, Cx43, Bmp2, Bmp5, Fgf2, Fgf13, Pgf, Ereg, Bdnf and Ngf in GFSca-1+. Expression of mir-1 and mir-206 was significantly increased in GFSca-1+ (p<0.01 vs ScSca-1+). LDH and TUNEL assays showed higher survival of GFSca-1+ under lethal anoxia (p<0.01 vs ScSca-1+). For in vivo study, female mice were grouped to receive the intramyocardial injection of 15 μ l DMEM without cells (group1) or containing 2.5x105 ScSca-1+ (group2) or GFSca-1+ (group3) immediately after coronary artery ligation. Real time PCR for Sry gene (n=6/group) showed significant survival of GFSca-1+ in group3 on day7 (2.3 fold higher vs group2) with massive mobilization of stem and progenitor cells (cKit+, MDR1+, CD31+, CXCR4+; p<0.01 vs other treatment groups). Confocal imaging of heart tissue sections immunostained for myosin heavy chain combined with Cx43 at 8 weeks post engraftment showed extensive myogenesis. Blood vessel density was highest in group-3 (22 ± 3 /field at 400x). Infarct size was attenuated by 18% in group3 as compared to group2 and the heart function indices were improved in group3 (52±2% LVEF p<0.01 and 21.7±1% LVFS p<0.01 vs group2).
Conclusions: Sca1+ bone marrow stem cells engraftment combined with multiple gene delivery is a novel approach to regenerate cardiovascular tissue in infarcted heart.
- © 2011 by American Heart Association, Inc.