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DOI: 10.1055/s-2004-816713
„Homing effect“ directs mesenchymal stem cells to develop a myogenic phenotype
Objectives: The transplantation of stem cells seems to become a promising new strategy for the treatment of patients with end stage heart failure. In this study we investigated the capacity of mesenchymal stem cells transplanted into rat myocardium to develop a myogenic phenotype.
Methods: Rat MSCs were separated by seeding cells into culture bottles and discarting the non adherent population 24h later. For a later detection within the target area the eGFP gene was introduced into the rMSCs. The chest of the rats was opened via mini-thoracothomy, a cryolesion generated and 1 Mill. cells (5 injections; 50µl each) were injected into the border zone the lesion (6×4mm). 3 weeks later rats were sacrificed, hearts excised and analysed via fluorescence microscopy and immunohistochemistry. The following mAbs were used: Smooth muscle actin (SMA), muscle actin (MA), troponin T-C, myosin heavy chain (MHC), desmin and the endothelial cell specific marker CD31.
Results: Rat MSCs within the target tissue showed a high rate of viability (70–80%). Furthermore single rMSCs were detected that could be stained positive for myocyte specific markers. However, the cells did not develop myofibers in this early state of development. In addition we could find a high incidence of small blood vessels in the transplantation area.
Conclusion:
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The „homing effect“ of injured rat myocardium might direct transplanted rMSCs into a myogenic differentiation pathway.
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The finding of a high incidence of blood vessels within the transplantation area might point to an angiogenic potential of rMSCs as well.
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These findings have to be verified in additional experiments with a longer follow up of at least 6 weeks.