Magnetic Resonance Tracking of Human CD34 + Progenitor Cells Separated by Means of Immunomagnetic Selection and Transplanted Into Injured Rat Brain

Magnetic resonance imaging (MRI) provides a noninvasive method for studying the fate of transplanted cells in vivo. We studied whether superparamagnetic nanoparticles (CD34 microbeads), used clinically for specific magnetic sorting, can be used as a magnetic cell label for in vivo cell visualization. Human cells from peripheral blood were selected by CliniMACS ® CD34 Selection Technology (Miltenyi). Purified CD34 + cells were implanted into rats with a cortical photochemical lesion, contralaterally to the lesion. Twenty-four hours after grafting, the implanted cells were detected in the contralateral hemisphere as a hypointense spot on T 2 weighted images; the hypointensity of the implant decreased during the first week. At the lesion site we observed a hypointensive signal 10 days after grafting that persisted for the next 3 weeks, until the end of the experiment. Prussian blue and anti-human nuclei staining confirmed the presence of magnetically labeled human cells in the corpus callosum and in the lesion 4 weeks after grafting. CD34 + cells were also found in the subventricular zone (SVZ). Human DNA (a human-specific 850 base pair fragment of αsatellite DNA from human chromosome 17) was detected in brain tissue sections from the lesion usin