Combining pharmacological mobilization with intramyocardial delivery of bone marrow cells over-expressing VEGF is more effective for cardiac repair

Self Cite

167

110

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, 4h transfection) with 125μM ZnCl 2 (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 70μl DMEM without cells (group-1) or containing 1.5×10 6 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.

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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

Elmadbouh

Haider

Jiang

et al. 2007

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167

110

“…One approach to this challenge is a two-stage process, where pro-vascularization interventions are employed initially, followed by seeding of a myogenic population. In any case, vascularization is clearly required for long term graft survival, and several studies have found over-expression of vascular endothelial growth factor (VEGF) enhances grafted cell survival [74][75][76]. Interestingly, adenoviral over-expression of hypoxia inducible factor-1α (HIF-1α) [77] with grafted skeletal myoblasts increased graft cell number, blood vessel formation and cardiac function.…”

Section: Strategies To Increase Cell Survivalmentioning

confidence: 99%

Systems approaches to preventing transplanted cell death in cardiac repair

Robey

Saiget

Reinecke

et al. 2008

366

294

Stem cell transplantation may repair the injured heart, but tissue regeneration is limited by death of transplanted cells. Most cell death occurs in the first few days post-transplantation, likely from a combination of ischemia, anoikis and inflammation. Interventions known to enhance transplanted cell survival include heat shock, over-expressing anti-apoptotic proteins, free radical scavengers, anti-inflammatory therapy and co-delivery of extracellular matrix molecules. Combinatorial use of such interventions markedly enhances graft cell survival, but death still remains a significant problem. We review these challenges to cardiac cell transplantation and present an approach to systematically address them.Most anti-death studies use histology to assess engraftment, which is time-and labor-intensive. To increase throughput, we developed two biochemical approaches to follow graft viability in the mouse heart. The first relies on LacZ enyzmatic activity to track genetically modified cells, and the second quantifies human genomic DNA content using repetitive Alu sequences. Both show linear relationships between input cell number and biochemical signal, but require correction for the time lag between cell death and loss of signal. Once optimized, they permit detection of as few as 1 graft cell in 40,000 host cells. Pro-survival effects measured biochemically at three days predict long-term histological engraftment benefits. These methods permitted identification of carbamylated erythropoietin (CEPO) as a pro-survival factor for human embryonic stem cell-derived cardiomyocyte grafts. CEPO's effects were additive to heat shock, implying independent survival pathways. This system should permit combinatorial approaches to enhance graft viability in a fraction of the time required for conventional histology.

“…The immunohistochemical studies were performed as described previously [10,11]. Cells were labeled with a reliable cell marker, green fluorescent protein (GFP).…”

Section: Immunohistochemistry and Fish Analysismentioning

confidence: 99%

Over-expression of CXCR4 on mesenchymal stem cells augments myoangiogenesis in the infarcted myocardium

Zhang

Fan

Zhou

et al. 2008

Self Cite

257

218

Bone marrow mesenchymal stem cells (MSCs) participate in myocardial repair following myocardial infarction. However, their in vivo reparative capability is limited due to lack of their survival in the infarcted myocardium. To overcome this limitation, we genetically engineered male rat MSCs overexpressing CXCR4 in order to maximize the effect of stromal cell-derived factor-1α (SDF-1α) for cell migration and regeneration. MSCs were isolated from adult male rats and cultured. Adenoviral transduction was carried out to over-express either CXCR4/green fluorescent protein (Ad-CXCR4/GFP) or Ad-null/GFP alone (control). Flow cytometry was used to identify and isolate GFP/CXCR4 over-expressing MSCs for transplantation. Female rats were assigned to one of four groups (n = 8 each) to receive GFP-transduced male MSCs (2 × 10 6 ) via tail vein injection 3 days after ligation of the left anterior descending (LAD) coronary artery: GFP-transduced MSCs (Ad-null/ GFP-MSCs, group 1) or MSCs over-expressing CXCR4/GFP (Ad-CXCR4/GFP-MSCs, group 2), or Ad-CXCR4/GFP-MSCs plus SDF-1α (50 ng/μl) (Ad-CXCR4/GFP-MSCs/SDF-1α, group 3), or Ad-miRNA targeting CXCR4 plus SDF-1α (Ad-miRNA/GFP-MSCs + SDF-1α treatment, group 4). Cardiodynamic data were obtained 4 weeks after induction of regional myocardial infarction (MI) using echocardiography after which hearts were harvested for immunohistochemical studies. The migration of GFP and Y-chromosome positive cells increased significantly in the peri-and infarct areas of groups 2 and 3 compared to control group (p<0.05), or miRNA-CXCR4 group (p<0.01). The number of CXCR4 positive cells in groups 2, 3 was intimately associated with angiogenesis and myogenesis. MSCs engraftment was blocked by pretreatment with miRNA (group 4). Cardiac function was significantly improved in rats receiving MSCs over-expressing CXCR4 alone or with SDF-1α. The up-regulation of matrix metalloproteinases (MMPs) by CXCR4 overexpressing MSCs perhaps facilitated their engraftment in the collagenous tissue of the infarcted area. CXCR4 overexpression led to enhance in vivo mobilization and engraftment of MSCs into ischemic area where these cells promoted neomyoangiogenesis and alleviated early signs of left ventricular remodeling.