Artikel
Tracking transplanted cells using anorganic or organic dye strategies
Anorganische oder organische Markierungstrategien im Monitoring transplantierter Zellen
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Veröffentlicht: | 30. Mai 2008 |
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Gliederung
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Objective: Monitoring the graft is of fundamental importance to understand and estimate the impact of cell replacement in the concept of transplantation as a therapeutic approach for different diseases. To unequivocally identify and track the graft over a longer period in the host tissue the labeling must be stably incorporated by the cells and should not be transferred to endogenous cells. Furthermore cell function should not be compromised by the labeling technique. In dependency of the scientific question for in vivo imaging the usage of long lasting fluorescence dyes is essential.
Methods: In the first and second mode murine fetal neural stem cells (mfNSC) were stained with anorganic non-fluorescence (very small iron oxid particles (VSOPs) and alternatively fluorescence dyes (PKH-26 and TAMRA) in vitro. In a third manner mfNSC were prepared from transgenic mice expressing a cyano fluorescence protein (CFP) under the control of a β-Actin-Chicken-Promotor. Thereafter cells were transplanted after traumatic brain injury using the Controlled Cortical Impact (CCI) model. To different timepoints (3d, 7, 28 and 84) animals were sacrificed and the graft localized and characterized by immunohistochemistry.
Results: Transgenic mfNSC expressing CFP can be prepared and show longlasting fluorescence over many passages and in other aspects no difference to wild type stem cells. Cells can also easily be stained with VSOPs and PKH-26 or TAMRA. Although transfection/staining rates and cell survival a very high (>90%), costaining with immunohistochemical methods is impaired with fluorescence dyes. VSOP can also be used to monitor the graft in MRI but are not useful for microscopic in vivo monitoring due to their non-fluorescence. PKH-26 and Tamra show a high and longlasting fluorescence in vitro as well as in vivo, but fail to show cellular processes and integration in later timepoints, which was possible with the transgenic CFP expressing stem cells.
Conclusions: Anorganic dyes fulfill most requirements for tracking the graft but fail to visualize extensions and by that structural integration because of redeployment of the dye into special intracellular compartments over time. Organic dyes like the cyano fluorescence protein overcome this restriction and are by that the perfect tool for monitoring most transplantation experiments.