title: [MR R2*map for tracing superparamgnetic ironoxides labeled endothelial progenitor cells in vitro].
abstract: OBJECTIVE
  To investigate the value of R2*map for quantitatively tracing superparamgnetic ironoxides (SPIO) labeled endothelial progenitor cells (EPCs).
  
  
  METHODS
  The EPCs were isolated from Balb/c mice bone marrow and cultured in vitro. After 7 days, expression of acetylated low-density lipoprotein (acLDL) and Ulex europaeus agglutinin-1 (UEA-1), two markers of EPCs, was observed by double staining using fluorescence microscope, the expression of stem cell antigen-1 and vascular endothelial growth factor receptor-2 (VEGFR-2) was confirmed by flow cytometry. EPCs were labeled by incubating with 50 microg/ml SPIO and 6 microl/ml lipofectamine2000, SPIO labeled EPCs were observed under transmission electron microscope (TEM). Labeled and unlabeled EPCs were mixed with 10 g/L agarose and scanned using a 3.0T MR scanner, R2* map and R2 map images were obtained on workstation.
  
  
  RESULTS
  After 7 days of in vitro culture, most of the cells showed characteristics of EPCs. There was no morphological difference between SPIO labeled EPCs and unlabeled EPCs. R2* and R2 values exhibited a linear correlation with the number of labeled cells in the agarose gel. Compared to R2, R2* was a better indicator of the number of labeled cells.
  
  
  CONCLUSIONS
  MR R2* map can be used to trace SPIO labeled EPCs quantitatively.
authors.affiliation: Department of Radiology, Zhongshan Hospital, Fudan University, Shanghai 200032, China.
authors.forename: Qing-Guo
authors.initials: QG
authors.lastname: Wang
authors.forename: Fu-Hua
authors.initials: FH
authors.lastname: Yan
authors.forename: Pen-Ju
authors.initials: PJ
authors.lastname: Xu
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology*; D005290:Ferric Compounds / Q000737:chemistry*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008280:Magnetics; D051379:Mice; D008807:Mice, Inbred BALB C; D053758:Nanoparticles / Q000737:chemistry; D013234:Stem Cells / Q000166:cytology*
chemical_list: D005290:Ferric Compounds; C000499:ferric oxide