Identification and 7.0 T magnetic resonance imaging of murine bone marrow-derived endothelial progenitor cells

Abstract

To label murine bone marrow derived endothelial progenitor cells (EPCs) with nanometer magnetic probe (Resovist) and perform magnetic resonance (MR) imaging on these labeled cells. Murine bone marrow derived mononuclear cells (MNCs) were isolated. And EPCs were selected by adherence method, expanded and incubated with Resovist. Cell surface markers were detected with immunofluorescence. Endocytosis of Dil-AcLDL (dil-labeled acetylated low density lipoprotein) and in vitro binding of FITC-UEA-1 (fluorescein isothiocyanate-vicia ervilia lectin-1) were also detected. Intracellular iron was detected by Prussian blue dye. Different quantities of labeled cells were visualized by 7.0T MR. The cultured cells expressed the endothelial cell markers of CD31 and KDR with immunofluorescence. The cells could bind UEA and endocytosis LDL. Iron particles could be observed in cells with Prussian blue dying and the ratio of label was approximately 100 percent. The Resovist labeled cells showed a lower signal than the non-labeled counterparts on T(2)(*)WI (weighted imaging), especially the 1×10(6) labeled cells showed the lowest signal. Murine bone marrow derived MNCs can be induced into EPCs and Resovist can label them effectively. The labeled cells can be visualized in vitro by 7.0T MR for cellular therapy and real time in vivo monitor.