Abstract
IntroductionElevated midkine (MK) expression may contribute to ventricular remodeling and ameliorate cardiac dysfunction after myocardial infarction (MI). Ex vivo modification of signaling mechanisms in mesenchymal stem cells (MSCs) with MK overexpression may improve the efficacy of cell-based therapy. This study sought to assess the safety and efficacy of MSCs with MK overexpression transplantation in a rat model of MI.MethodsA pLenO-DCE vector lentivirus encoding MK was constructed and infected in MSCs. MSC migration activity and cytoprotection was examined in hypoxia-induced H9C2 cells using transwell insert in vitro. Rats were randomized into five groups: sham, MI plus injection of phosphate buffered saline (PBS), MSCs, MSCs-green fluorescent protein (MSCs-GFP) and MSCs-MK, respectively. Survival rates were compared among groups using log-rank test and left ventricular function was measured by echocardiography at baseline, 4, 8 and 12 weeks.ResultsOverexpression of MK partially prevented hypoxia-induced MSC apoptosis and exerted MSC cytoprotection to anoxia induced H9C2 cells. The underlying mechanisms may be associated with the increased mRNA and protein levels of vascular endothelial growth factor (VEGF), transformation growth factor-β (TGF-β), insulin-like growth factor 1 (IGF-1) and stromal cell-derived factor 1 (SDF-1a) in MSCs-MK compared with isolated MSCs and MSCs-GFP. Consistent with the qPCR results, the culture supernatant of MSCs-MK had more SDF-1a (9.23 ng/ml), VEGF (8.34 ng/ml) and TGF-β1 (17.88 ng/ml) expression. In vivo, a greater proportion of cell survival was observed in the MSCs-MK group than in the MSCs-GFP group. Moreover, MSCs-MK administration was related to a significant improvement of cardiac function compared with other control groups at 12 weeks.ConclusionsTherapies employing MSCs with MK overexpression may represent an effective treatment for improving cardiac dysfunction and survival rate after MI.
Highlights
Elevated midkine (MK) expression may contribute to ventricular remodeling and ameliorate cardiac dysfunction after myocardial infarction (MI)
Characterization of mesenchymal stem cells (MSCs)-MK After three passages, the adherent MSC cells were symmetric with phenotypic surface antigens as reported, including positivity for CD29, CD44 and CD90 and negativity for CD34, CD31 and CD86 (>90%, Figure S1 in Additional file 1) [22,29,30]
To determine whether MK impacts the expression of pro-angiogenesis and some stem cellrelated factors, we measured mRNA of vascular endothelial growth factor (VEGF), transformation growth factor-β (TGF-β), FGF2, FGF7, SDF-1a, insulin-like growth factor 1 (IGF-1), Granulocyte-macrophage colony-stimulating factor (GM-CSF) and Stem cell factor (SCF) in MSCs, MSCs-MK and MSCs-green fluorescent protein (GFP) respectively (Figure 2A,B), and the protein levels of IGF-1, SDF-1a, VEGF and TGF-β1 were quantified by ELISA (Figure 2C)
Summary
Elevated midkine (MK) expression may contribute to ventricular remodeling and ameliorate cardiac dysfunction after myocardial infarction (MI). Ex vivo modification of signaling mechanisms in mesenchymal stem cells (MSCs) with MK overexpression may improve the efficacy of cell-based therapy. A number of studies have documented that mesenchymal stem cell (MSC) therapy may have a favorable impact on cardiac function in experimental animal models or patients after. Our previous studies reported that autologous bone marrow MSCs transplantation improved cardiac function in 96 patients with acute MI who experienced percutaneous coronary intervention and the cardioprotective effect remained six months after the procedure [7,8]. Studies from several preclinical experiments suggested that genetic strategies may play a critical role in improving MSC survival and differentiation [9,10,11,12,13]. MK application is recently regarded as a new therapeutic strategy for the treatment of ischemic heart failure [19,20]
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