Artikel
Neural differentiation and transplantation of human cord blood (HCB) derived mesenchymal stem cells (MSC)
Neuronale Differenzierung und Transplantation humaner mesenchymaler Stammzellen (MSC) aus Nabelschnurblut (HCB)
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Veröffentlicht: | 30. Mai 2008 |
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Gliederung
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Objective: HCB is considered to be a valuable source of stem cells in the field of neurorestoration research. It contains in the mononuclear cell (MNC) fraction a certain number of MSC that are able to proliferate and to differentiate in vitro into various cell types. MSC derived from HCB seem to have the same potential as the MSC derived from bone marrow. The objective of this project was to propagate HCB-derived MSC and to study their differentiation potential in vitro in cell culture systems. Furthermore, we transplanted these cells into the rat brain to study their behaviour in vivo.
Methods: HCB probes were collected after informed consent of mothers. MNC were isolated from HCB by Ficoll density-gradient centrifugation and plastic adherent MSC were cultured in MSC medium. Proliferating spindle-shape MSC were neurally pre-differentiated by exposure to bFGF and EGF for 1 week. Then cells were further differentiated in defined media up to 3 weeks. Cells were fixed at several time points and processed for immunocytochemistry. To investigate the in vivo behaviour, magnetic resonance imaging (MRI in vivo imaging) was used. MSC were labelled with iron based contrast agents. For stereotactic transplantation into the striatum and the hippocampus of SD female rats, a single cell suspension of either proliferating or differentiated cells was used. Grafts were examined by MRI 2, 4, 8 and 12 weeks after transplantation. The rats were immunosuppressed during the entire experiment, and sacrificed at different time points (up to 16 weeks). The brains were subjected to immunohistochemistry.
Results: After 3 weeks in MSC culture medium, cell morphology reached a spindle-shape and cells started proliferating faster. At this stage, bFGF and EGF exposure changed towards neural phenotype expressing nestin, GFAP and bIIItubulin. Differentiation increased the expression of the neural markers NF-200, NF-M, MAP-2 and promoted GAD65 expression and GABA production. MRI scans revealed short and long-term neural graft survival in the striatum as well as in the hippocampus. These results can be correlated to the immunohistochemistry outcome of the transplanted brains.
Conclusions: Our results show that it is possible to isolate MSC from HCB, to proliferate and differentiate them into cells expressing stem cell as well as neuronal markers. The in vivo results suggest that HCB derived MSC have the potential to survive in the rat brain and can eventually be used as a cell source for cell replacement therapy in neurodegenerative disorders.