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DOI: 10.1055/s-0030-1269112
Noninvasive in vivo tracking of mesenchymal stem cells by MRI and evaluation of cell therapeutic effects
Introduction: Stem cell transplantation is emerging as a promising approach for the regeneration of infarcted myocardium. The goal of this study is the in vivo analysis of stem cell transplantation with respect to localization and therapeutic efficect by magnetic resonance imaging (MRI) in a murine model.
Methods: Murine mesenchymal stem cells (mMSC) were isolated from bone marrow and cell line specificity was confirmed in vitro by adipo-, chondro- and osteo-differentiation and FACS-analysis after expansion. mMSC were labeled with paramagnetic microspheres (Ø 0.9µm) and transplanted into the border zone of the infarcted myocardium. In vivo cell tracking and measurements of functional cardiac parameters were performed using a clinical 3T MRI-scanner with a dedicated magnification coil for mice.
Results: Microspheres were phagocytosed by mMSC efficiently, without interfering with their proliferation and differentiation potential. A minimum of 10,000 transplanted mMSC could be localized by MRI five days after transplantation. Sequential tracking of 100,000 labeled cells for four weeks showed local preservation of the signal, indicating that cells are retained at the site of injection. Compared to sham-controls, cell transplanted animals showed significant improvement of left ventricular ejection fraction (53.3±3.4% vs. 30.4±2.2%; p<0.05) four weeks postoperatively.
Conclusion: Intramyocardial transplantation of mesenchymal stem cells into infarcted hearts resulted in improvement of left ventricular function. In addition we could show that in vivo tracking of transplanted cells in small animal models is feasible using a clinical MRI set-up and opens new ways to elucidate the mechanisms of cardiac cell therapy.