ABSTRACT
OBJECTIVE: To assess migration of CD34(+) human stem cells to the bone marrow of athymic mice by using magnetic resonance (MR) imaging and Resovist, a contrast agent containing superparamagnetic iron oxide (SPIO) particles. METHODS: All animal and human procedures were approved by our institution's ethics committee, and women had given consent to donate umbilical cord blood (UCB). Balb/c-AnN Foxn1(nu)/Crl mice received intravenous injection of 1 x 10(6) (n=3), 5 x 10(6) (n=3) or 1 x 10(7) (n=3) human Resovist-labelled CD34(+) cells; control mice received Resovist (n=3). MR imaging was performed before, 2 and 24 h after transplantation. Signal intensities of liver, muscle and bone marrow were measured and analysed by ANOVA and post hoc Student's t tests. MR imaging data were verified by histological and immunological detection of both human cell surface markers and carboxydextrancoating of the contrast agent. RESULTS: CD34(+) cells were efficiently labelled by Resovist without impairment of functionality. Twenty-four hours after administration of labelled cells, MR imaging revealed a significant signal decline in the bone marrow, and histological and immunological analyses confirmed the presence of transplanted human CD34(+) cells. CONCLUSION: Intravenously administered Resovist-labelled CD34(+) cells home to bone marrow of mice. Homing can be tracked in vivo by using clinical 1.5-T MR imaging technology.
Subject(s)
Cell Tracking/methods , Common Variable Immunodeficiency/immunology , Common Variable Immunodeficiency/pathology , Dextrans , Hematopoietic Stem Cell Transplantation/methods , Immunocompromised Host/immunology , Magnetic Resonance Imaging/methods , Magnetite Nanoparticles , Animals , Cells, Cultured , Common Variable Immunodeficiency/surgery , Contrast Media , Female , Humans , Mice , Mice, Inbred BALB C , Mice, Nude , Staining and Labeling/methodsABSTRACT
Expression of "stemness" markers is widely used as a predictor of stem cell properties of mesenchymal stem cells (MSC). Here, we show that bone marrow-derived (BM)-MSC show stem cell-like behavior in vivo; that is, they form ossicles with formation of bone, formation of adipocytes, and establishment of the murine hematopoietic microenvironment. Multipotent umbilical vein-derived stromal cells (UVSC), on the other hand, do not form bone, nor do they give rise to adipocytes in vivo. Despite these differences in stem-cell-like behavior, BM-MSC and UVSC express the two transcripts variants of POU5F1 at a similar level. Also, we found that in BM-MSC and UVSC, POU5F1 is detectable. However, more than 89% of the POU5F1 transcripts correspond to the POU5F1P1, -P3, or -P4 pseudogene. Despite low-level expression of POU5F1, we were unable to precipitate POU5F1 protein in either BM-MSC or UVSC. These results demonstrate that MSC stemness does not correlate to expression of POU5F1 transcripts or its pseudogenes.
