Abstract
Background. Magnetic resonance imaging provides a noninvasive method to study the fate of transplanted cells in vivo.
Objective: We studied the fate of embryonic and mesenchymal stem cells labeled with iron oxide nanoparticles (Endorem(R)) and human CD34+ cells labeled with magnetic MicroBeads (Miltenyi) in rats with a cortical or spinal cord lesion. Methods: Cells were grafted intracerebrally, contralaterally to a cortical photochemical lesion, or injected intravenously.
Results: During the 1st week after transplantation, transplanted cells migrated to the lesion and were visible in the lesion on MR images as a hypointensive signal, persisting for more than 30 days. In rats with a balloon-induced spinal cord compression lesion, we observed an increase in functional recovery and hind limb sensitivity after implantation of Endorem-labeled mesenchymal stem cells or a freshly prepared mononuclear fraction of bone marrow cells or after injection of granulocyte colony-stimulating factor.
Morphometric measurements in the center of the lesions showed an increase in white matter volume in cell-treated animals. Prussian blue staining confirmed a large number of Prussian blue-positive cells, and the lesions were considerably smaller than in control animals.
Conclusions: These studies demonstrate that magnetic resonance imaging of grafted adult as well as embryonic stem cells labeled with iron oxide nanoparticles is a useful method for evaluating their migration and fate in CNS.