Ex vivo delivered stromal cell-derived factor-1α promotes stem cell homing and induces angiomyogenesis in the infarcted myocardium

We aimed to optimize non-viral transfection of human stromal cell derived factor (SDF-1α) gene into skeletal myoblasts (SkM) and, transplant these cells to establish transient SDF-1α gradient to favor extra-cardiac stem cell translocation into infarcted heart. Optimized conditions for transfection of SDF-1α gene into syngenic SkM were achieved using FuGene™6/phSDF-1α (3:2v/w, 4 h transfection) with 125 μM ZnCl₂ (p < 0.001). After characterization for transgene overexpression by immunostaining, ELISA and PCR, the cells were transplanted in female rat model of myocardial infarction. Thirty-six rats were grouped (n = 12/group) to receive 70 μl DMEM without cells (group-1) or containing 1.5 × 10⁶ non-transfected (group-2) or SDF-1α transfected SkM (group-3). On day 4 post-transplantation (in 4 animals/group), marked expression of SDF-1α/sry-gene (p = 0.003), total Akt, phospho-Akt and Bcl2 was observed in group-3. The number of CD31⁺, C-kit⁺ and CD34⁺ cells was highest in group-3 hearts (p < 0.01). Blood vessel density in group-3 was higher in both scar and peri-scar regions (p < 0.001) as compared with other groups. Echocardiography showed improved indices of left ventricle contractile function and remodeling in group-3 (p < 0.05) as compared with groups-1 and -2. We conclude that ex vivo SDF-1α transgene delivery promotes stem and progenitor cell migration to the heart, activates cell survival signaling and enhances angiomyogenesis in the infarcted heart.