title: Optimization of the magnetic labeling of human neural stem cells and MRI visualization in the hemiparkinsonian rat brain.
abstract: BACKGROUND
  Magnetic resonance imaging is the ideal modality for non-invasive in vivo cell tracking allowing for longitudinal studies over time. Cells labeled with superparamagnetic iron oxide nanoparticles have been shown to induce sufficient contrast for in vivo magnetic resonance imaging enabling the in vivo analysis of the final location of the transplanted cells. For magnetic nanoparticles to be useful, a high internalization efficiency of the particles is required without compromising cell function, as well as validation of the magnetic nanoparticles behaviour inside the cells.
  
  
  RESULTS
  In this work, we report the development, optimization and validation of an efficient procedure to label human neural stem cells with commercial nanoparticles in the absence of transfection agents. Magnetic nanoparticles used here do not affect cell viability, cell morphology, cell differentiation or cell cycle dynamics. Moreover, human neural stem cells progeny labeled with magnetic nanoparticles are easily and non-invasively detected long time after transplantation in a rat model of Parkinson's disease (up to 5 months post-grafting) by magnetic resonance imaging.
  
  
  CONCLUSIONS
  These findings support the use of commercial MNPs to track cells for short- and mid-term periods after transplantation for studies of brain cell replacement therapy. Nevertheless, long-term MR images should be interpreted with caution due to the possibility that some MNPs may be expelled from the transplanted cells and internalized by host microglial cells.
authors.affiliation: Centre for Biomedical Technology, Polytechnic University of Madrid, 28223, Madrid, Spain. milagros.ramos@ctb.upm.es.|Biomedical Research Networking Center in Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain. milagros.ramos@ctb.upm.es.
authors.forename: Milagros
authors.initials: M
authors.lastname: Ramos-Gómez
authors.affiliation: Department of Molecular Biology and Center of Molecular Biology "Severo Ochoa", Autonomous University of Madrid-C.S.I.C, 28049, Madrid, Spain. egonzalez@cbm.uam.es.
authors.forename: Emma G
authors.initials: EG
authors.lastname: Seiz
authors.affiliation: Department of Molecular Biology and Center of Molecular Biology "Severo Ochoa", Autonomous University of Madrid-C.S.I.C, 28049, Madrid, Spain. amserrano@cbm.csic.es.
authors.forename: Alberto
authors.initials: A
authors.lastname: Martínez-Serrano
mesh_terms: D000818:Animals; D001921:Brain / Q000473:pathology*; D002470:Cell Survival; D058948:Cell Tracking / Q000379:methods; D017690:Cell Transplantation / Q000379:methods; D002478:Cells, Cultured; D003911:Dextrans / Q000737:chemistry; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D058953:Neural Stem Cells / Q000737:chemistry* / Q000166:cytology / Q000637:transplantation; D010300:Parkinson Disease / Q000473:pathology*; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D014162:Transfection / Q000379:methods
chemical_list: D003911:Dextrans; D058185:Magnetite Nanoparticles; C065507:ferumoxides