title: MRI of magnetically labeled mesenchymal stem cells in hepatic failure model.
abstract: OBJECTIVE
  To track intravascularly transplanted mesenchymal stem cells (MSCs) labeled with superparamagnetic iron oxide (SPIO) by using magnetic resonance imaging (MRI) in an experimental rabbit model of hepatic failure.
  
  
  METHODS
  Human MSCs labeled with FDA-approved SPIO particles (Feridex) were transplanted via the mesenteric vein into rabbits (n = 16) with carbon tetrachloride-induced hepatic failure. Magnetic resonance (MR) examinations were performed with a 3.0 T clinical scanner immediately before and 2 h and 1, 3, and 7 d after transplantation. Signal intensity (SI) changes on T2*-weighted MRI were measured, and correlation between MR findings and histomorphologic findings was also investigated.
  
  
  RESULTS
  SI on T2*-weighted MRI decreased significantly in the liver 2 h after injection of human MSCs and returned gradually to the levels found before injection in 7 d. Changes in SI in the liver at 2 h, 1, 3, and 7 d were 41.87% ± 9.63%, 10.42% ± 4.3%, 5.12% ± 1.9%, 3.75% ± 1.2%, respectively (P < 0.001). Histologic analyses confirmed the presence of MSCs in the liver, localized mainly in the sinusoids in early period (2 h and 1 d) and concentrated to the border zone in late period (3 and 7 d). The number of iron-positive cells in the liver at 2 h and on 1, 3 and 7 d after transplantation was 29.2 ± 4.8, 10.1 ± 3.7, 6.7 ± 2.2, and 5.8 ± 2.1, respectively (P = 0.013).
  
  
  CONCLUSIONS
  Intravascularly injected SPIO-labeled MSCs in an experimental rabbit model of hepatic failure can be detected and followed with MRI.
authors.affiliation: Department of Radiology, Seoul National University College of Medicine, Institute of Radiation Medicine, Seoul National University Medical Research Center, and Chongno-gu, Seoul 110-744, South Korea.
authors.forename: Kyu Ri
authors.initials: KR
authors.lastname: Son
authors.forename: Se Young
authors.initials: SY
authors.lastname: Chung
authors.forename: Hyo-Cheol
authors.initials: HC
authors.lastname: Kim
authors.forename: Hoe Suk
authors.initials: HS
authors.lastname: Kim
authors.forename: Seung Hong
authors.initials: SH
authors.lastname: Choi
authors.forename: Jeong Min
authors.initials: JM
authors.lastname: Lee
authors.forename: Woo Kyung
authors.initials: WK
authors.lastname: Moon
mesh_terms: D000818:Animals; D002251:Carbon Tetrachloride; D002465:Cell Movement; D002478:Cells, Cultured; D003287:Contrast Media; D003911:Dextrans; D004195:Disease Models, Animal; D005240:Feasibility Studies; D006801:Humans; D007275:Injections, Intravenous; D008099:Liver / Q000473:pathology*; D017093:Liver Failure / Q000139:chemically induced / Q000473:pathology / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D058185:Magnetite Nanoparticles; D045164:Mesenchymal Stem Cell Transplantation; D008642:Mesenteric Veins; D011817:Rabbits; D013997:Time Factors
chemical_list: D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D002251:Carbon Tetrachloride; C065507:ferumoxides