Abstract 1324: Endothelial Stem Cell Detection in vivo with Unique Perfluorocarbon Nanoparticle Labels Using Fluorine (19F) MRI at 1.5 T
Endothelial progenitor cells migrate to and populate areas of myocardial ischemia, where they are instrumental in vasculogenesis. Magnetic resonance imaging, due to its high spatial resolution and lack of ionizing radiation, is an ideal imaging modality for tracking cell migration. However, current cell labeling strategies employ iron oxide particles, which create signal deficits on standard 1H MR images that can be obscured by background artifacts. We have developed a liquid perfluorocarbon nanoparticle, which can be safely used for stem/progenitor cell labeling and produces a unique bright signal on 19F MR images with no competing background signal. For demonstration of concept, mononuclear cells were isolated from human umbilical cord blood, grown in endothelial media to induce differentiation, and then incubated with the nanoparticles for 12 hours. Nude mice were inoculated with C32 human melanoma cells (~106) in the right inguinal area to induce tumor formation and recruit endothelial cells. Twelve days post-implantation, the mice were injected with live, labeled stem/progenitor cells (~3x106) in the right leg, near but not adjacent to the tumor. Fluorine imaging (bFFE sequence, ~3 min scan time) was performed the day of cell injection and 7 days later with a Philips Intera CV 1.5 T clinical scanner. A spatial change in the 19F signal emanating from the labeled cells is apparent on the image acquired 7 days post injection, potentially indicative of cell migration towards the tumor. We conclude that this unique cellular labeling method offers very fast and sensitive readouts for imaging labeled cells in vivo with MRI at clinical field strengths.