Antioxidants Improve Early Survival of Cardiomyoblasts After Transplantation to the Myocardium

Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA.
Molecular imaging and biology: MIB: the official publication of the Academy of Molecular Imaging (Impact Factor: 2.77). 12/2009; 12(3):325-34. DOI: 10.1007/s11307-009-0274-4
Source: PubMed


We tested the hypothesis that modulation of the microenvironment (using antioxidants) will increase stem cell survival in hypoxia and after transplantation to the myocardium.
Rat cardiomyoblasts were stably transfected with a reporter gene (firefly luciferase) for bioluminescence imaging (BLI). First, we examined the role of oxidative stress in cells under hypoxic conditions. Subsequently, stem cells were transplanted to the myocardium of rats using high-resolution ultrasound, and their survival was monitored daily using BLI.
Under hypoxia, oxidative stress was increased together with decreased cell survival compared to control cells, both of which were preserved by antioxidants. In living subjects, oxidative stress blockade increased early cell survival after transplantation to the myocardium, compared to untreated cells/animals.
Modulation of the local microenvironment (with antioxidants) improves stem cell survival. Increased understanding of the interaction between stem cells and their microenvironment will be critical to advance the field of regenerative medicine.

Download full-text


Available from: Karen Peterson,
  • Source
    • "Therefore, it is of major importance to address this problem in order to improve the engraftment and enhance the therapeutic efficacy of transplanted cells. BL imaging using FLuc is a powerful method for the quantitative assessment of cell survival in vivo and has frequently been used for longitudinal monitoring of various types of intramyocardially transplanted cells in small animals including adult stem cells [16], [40]–[46], fibroblasts [16], embryonic cardiomyoblasts [26], [47], [48], cardiac stem cells [24], [49]–[51], undifferentiated ESC [52], [53], ESC-derived endothelial cells [54] and ES-CM [22], [23], [31], [55]. In this study we describe the generation of transgenic murine iPSC lines in which constitutively active FLuc and CM-specific PAC and EGFP expression allow for isolation, longitudinal in vivo bioluminescent tracking and in situ fluorescent detection of highly purified iPS-CM. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Cell loss after transplantation is a major limitation for cell replacement approaches in regenerative medicine. To assess the survival kinetics of induced pluripotent stem cell (iPSC)-derived cardiomyocytes (CM) we generated transgenic murine iPSC lines which, in addition to CM-specific expression of puromycin N-acetyl-transferase and enhanced green fluorescent protein (EGFP), also constitutively express firefly luciferase (FLuc) for bioluminescence (BL) in vivo imaging. While undifferentiated iPSC lines generated by random integration of the transgene into the genome retained stable FLuc activity over many passages, the BL signal intensity was strongly decreased in purified iPS-CM compared to undifferentiated iPSC. Targeted integration of FLuc-expression cassette into the ROSA26 genomic locus using zinc finger nuclease (ZFN) technology strongly reduced transgene silencing in iPS-CM, leading to a several-fold higher BL compared to iPS-CM expressing FLuc from random genomic loci. To investigate the survival kinetics of iPS-CM in vivo, purified CM obtained from iPSC lines expressing FLuc from a random or the ROSA26 locus were transplanted into cryoinfarcted hearts of syngeneic mice. Engraftment of viable cells was monitored by BL imaging over 4 weeks. Transplanted iPS-CM were poorly retained in the myocardium independently of the cell line used. However, up to 8% of cells survived for 28 days at the site of injection, which was confirmed by immunohistological detection of EGFP-positive iPS-CM in the host tissue. Transplantation of iPS-CM did not affect the scar formation or capillary density in the periinfarct region of host myocardium. This report is the first to determine the survival kinetics of drug-selected iPS-CM in the infarcted heart using BL imaging and demonstrates that transgene silencing in the course of iPSC differentiation can be greatly reduced by employing genome editing technology. FLuc-expressing iPS-CM generated in this study will enable further studies to reduce their loss, increase long-term survival and functional integration upon transplantation.
    PLoS ONE 09/2014; 9(9):e107363. DOI:10.1371/journal.pone.0107363 · 3.23 Impact Factor

  • Current Cardiovascular Imaging Reports 06/2011; 4(3):173-174. DOI:10.1007/s12410-011-9080-x
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cell-based therapies are a potential therapeutic alternative for the treatment of coronary artery disease (CAD). However, transplanted cells undergo significant death in the living subject. Hypoxic preconditioning (HPC) is a potential intervention to increase transplanted cell survival. However, the biological mechanisms of this benefit remain unclear. We hypothesize that the beneficial effect of HPC on stem cell survival is in part due to preservation of oxidant status, an effect that will be monitored using state-of-the-art molecular imaging. H9c2 rat cardiomyoblasts expressing the construct CMV-firefly luciferase (h9c2-fluc), with and without HPC, were exposed to hypoxia, and oxidative stress and cell survival were measured. Subsequently, H9c2-fluc cells, with and without HPC, were injected into the myocardium of rats and cell survival was monitored daily with Bioluminescence (BLI) using a CCD camera. Compared to controls, cells exposed to hypoxia had increased amount of reactive oxygen species (ROS, control: 14.1±0.9 vs. hypoxia: 19.5 ± 2.0 RFU/µg protein, P=0.02) and decreased cell survival (control: 0.29 ± 0.005 vs. hypoxia: 0.24 ± 0.005 OD, P<0.001). HPC treatment decreased the amount of hypoxia-induced ROS (HPC: 11.5 ± 0.7RFU/µg protein, P=0.002 vs. hypoxia and P=0.11 vs. control), associated with improved survival (HPC: 0.27 ± 0.004OD/µg protein, P=0.002 vs. hypoxia and P=0.005 vs. control). Most importantly, compared to un-conditioned cells, HPC-cells had increased cell survival after transplantation to the myocardium (C: 34.7 ± 6.7% vs. HPC: 83.4 ± 17.5% at day 5 compared to day 1, P=0.01). The beneficial effect of HPC is in part due to preservation of oxidant status. Molecular imaging can assess changes in cell survival in the living subject and has the potential to be applied clinically.
    The Journal of cardiovascular surgery 08/2011; 52(4):579-85. · 1.46 Impact Factor
Show more