title: Behaviour of adipose-derived canine mesenchymal stem cells after superparamagnetic iron oxide nanoparticles labelling for magnetic resonance imaging.
abstract: BACKGROUND
  Therapy with mesenchymal stem cells (MSCs) has been reported to provide beneficial effects in the treatment of neurological and orthopaedic disorders in dogs. The exact mechanism of action is poorly understood. Magnetic resonance imaging (MRI) gives the opportunity to observe MSCs after clinical administration. To visualise MSCs with the help of MRI, labelling with an MRI contrast agent is necessary. However, it must be clarified whether there is any negative influence on cell function and viability after labelling prior to clinical administration.
  
  
  RESULTS
  For the purpose of the study, seven samples with canine adipose-derived stem cells were incubated with superparamagnetic iron oxide nanoparticles (SPIO: 319.2 μg/mL Fe) for 24 h. The internalisation of the iron particles occurred via endocytosis. SPIO particles were localized as free clusters in the cytoplasm or within lysosomes depending on the time of investigation. The efficiency of the labelling was investigated using Prussian blue staining and MACS assay. After 3 weeks the percentage of SPIO labelled canine stem cells decreased. Phalloidin staining showed no negative effect on the cytoskeleton. Labelled cells underwent osteogenic and adipogenic differentiation. Chondrogenic differentiation occurred to a lesser extent compared with a control sample. MTT-Test and wound healing assay showed no influence of labelling on the proliferation. The duration of SPIO labelling was assessed using a 1 Tesla clinical MRI scanner and T2 weighted turbo spin echo and T2 weighted gradient echo MRI sequences 1, 2 and 3 weeks after labelling. The hypointensity caused by SPIO lasted for 3 weeks in both sequences.
  
  
  CONCLUSIONS
  An Endorem labelling concentration of 319.2 μg/mL Fe (448 μg/mL SPIO) had no adverse effects on the viability of canine ASCs. Therefore, this contrast agent could be used as a model for iron oxide labelling agents. However, the tracking ability in vivo has to be evaluated in further studies.
authors.affiliation: Department of Veterinary Clinical Sciences, Clinic for Small Animal-Surgery, Faculty of Veterinary Medicine, Justus-Liebig-University Giessen, Giessen, Germany. Malgorzata.Kolecka@vetmed.uni-giessen.de.
authors.forename: Malgorzata Anna
authors.initials: MA
authors.lastname: Kolecka
authors.affiliation: Institute of Veterinary Anatomy, Histology and Embryology, Faculty of Veterinary Medicine, Justus-Liebig-University Giessen, Giessen, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Arnhold
authors.affiliation: Department of Veterinary Clinical Sciences, Clinic for Small Animal-Surgery, Faculty of Veterinary Medicine, Justus-Liebig-University Giessen, Giessen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Schmidt
authors.affiliation: Institute of Veterinary Anatomy, Histology and Embryology, Faculty of Veterinary Medicine, Justus-Liebig-University Giessen, Giessen, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Reich
authors.affiliation: Department of Veterinary Clinical Sciences, Clinic for Small Animal-Surgery, Faculty of Veterinary Medicine, Justus-Liebig-University Giessen, Giessen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Kramer
authors.affiliation: Institute of Biomathematics, Faculty of Veterinary Medicine, Justus-Liebig-University Giessen, Giessen, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Failing
authors.affiliation: Department of Veterinary Clinical Sciences, Clinic for Small Animal-Surgery, Faculty of Veterinary Medicine, Justus-Liebig-University Giessen, Giessen, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: von Pückler
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D003584:Cytological Techniques / Q000379:methods*; D004285:Dogs; D004705:Endocytosis; D005290:Ferric Compounds / Q000378:metabolism* / Q000633:toxicity; D008279:Magnetic Resonance Imaging; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000633:toxicity; D013194:Staining and Labeling
chemical_list: D005290:Ferric Compounds; C000499:ferric oxide
keywords: Canine adipose-derived mesenchymal stem cells; Endorem; Magnetic resonance; Superparamagnetic iron oxide particles