Abstract 2971: Heme Oxygenase-1 Gene Modified Mesenchymal Stem Cells Enhances Vasculogenesis on Post-infarct Swine Hearts
Objectives: The aim of this study was to explore if the beneficial effects of mesenchymal stem cells (MSCs) modified with Heme xygenase-1(HO-1) on post-infarct swine hearts was due to the induction of upregulated therapeutic angiogenesis.
Methods: In vitro, MSCs were divided into 4 groups: non-transfected MSCs (MSCs), MSCs transfected with pcDNA3.1- Lacz plasmid (Lacz -MSCs), MSCs transfected with pcDNA3.1- hHO-1 (HO-1-MSCs), and MSCs transfected with pcDNA3.1- hHO-1 pretreatment with a HO inhibitor, tin protoporphyrin (SnPP) (HO-1-MSCs+ SnPP), cells were cultured in an airtight incubation bottle for 24h, in which the oxygen concentration was maintained at <1%, and followed by 12h of reoxygenation. After hypoxia / reoxygen treatment, ELISA was used to measure TGF-β and FGF-2 in supernatant. In vivo, twenty-eight Chinese mini-pigs were randomly allocated to the following treatment groups: control group (saline), Lacz -MSCs group, HO-1-MSCs group, and HO-1-MSCs+ SnPP group. Autologous stem cells (1×107) or identical volume of saline was injected intracoronary into porcine hearts 1 h after myocardial infarction. MRI assay and postmortem analysis were assessed 4 weeks after stem cell transplantation.
Results: Post hypoxia/reoxygen in vitro, supernatant TGF-β significantly increased in HO-1-MSCs (874.9±68.2 pg/ml) compared with Lacz-MSCs (687.8±57.6 pg/ml, p<0.001), and FGF-2 also significantly enhanced in HO-1-MSCs (1106.5±107.1 pg/ml) compared with Lacz-MSCs (853.9±74.4 pg/ml, p<0.001). In vivo, at 4 weeks after transplantation, HO-1 gene transfer increased capillary density in the peri-infarct area compared with that in Lacz- MSCs group (14.2±1.7/ HPFs vs 11.5±1.3/ HPFs, p<0.001), arteriolar density was also significantly higher in HO-1-MSCs group than in Lacz-MSCs group (7.9±2.0 / HPFs vs 6.5±1.7 / HPFs, p<0.01), at the same time, the cardiac function was significantly improved in HO-1- MSCs group compared with that in Lacz- MSCs group (53.2±3.6% vs 48.8±3.0 %, p<0.05). However, all these effects were significantly attenuated by SnPP.
Conclusion: HO-1 overexpression amplified the beneficial effects of MSCs implantation on improving cardiac function post ischemia/reperfusion via induction of therapeutic angiogenesis.