title: Magnetic resonance monitoring of superparamagnetic iron oxide (SPIO)-labeled stem cells transplanted into the inner ear.
abstract: In the field of regenerative medicine, cell transplantation or cell-based therapies for inner ear defects are considered to be promising candidates for a therapeutic strategy. In this paper, we report on a study that examined the use of magnetic resonance imaging (MRI) to monitor stem cells transplanted into the cochlea labeled with superparamagnetic iron oxide (SPIO), a contrast agent commonly used with MRI. First, we demonstrated in vitro that stem cells efficiently took up SPIO particles. This was confirmed by Prussian blue staining and TEM. In MRI studies, T2 relaxation times of SPIO-labeled cells decreased in a dose-dependent manner. Next, we transplanted SPIO-labeled cells directly into the cochlea in vivo and then performed MRI 1h, 2 weeks, and 4 weeks after transplantation. The images were evaluated objectively by measuring signal intensity (SI). SI within the ears receiving transplants was significantly lower (P<0.05) than that of control sides at the 1-h assessment. This novel method will be helpful for evaluating stem cell therapies, which represents a new strategy for inner ear regeneration. To the best of our knowledge, this study is the first to demonstrate that local transplantation of labeled stem cells into the inner ear can be visualized in vivo via MRI.
authors: Department of Otorhinolaryngology, Head and Neck Surgery, Keio University School of Medicine, Tokyo, Japan.
authors: Yukiko
authors: Y
authors: Watada
authors: Department of Otorhinolaryngology, Head and Neck Surgery, Keio University School of Medicine, Tokyo, Japan; Department of Otorhinolaryngology, Head and Neck Surgery, Kobe University Hospital, Kobe, Japan.
authors: Daisuke
authors: D
authors: Yamashita
authors: Department of Department of Reproductive Biology, National Institute for Child Health and Development, Tokyo, Japan; Research Team for Vascular Medicine, Tokyo, Metropolitan Institute of Gerontology, Tokyo, Japan.
authors: Masashi
authors: M
authors: Toyoda
authors: Department of Department of Reproductive Biology, National Institute for Child Health and Development, Tokyo, Japan.
authors: Kohei
authors: K
authors: Tsuchiya
authors: Department of Department of Reproductive Biology, National Institute for Child Health and Development, Tokyo, Japan; Research Team for Vascular Medicine, Tokyo, Metropolitan Institute of Gerontology, Tokyo, Japan.
authors: Naoko
authors: N
authors: Hida
authors: Department of Diagnostic Radiology, Keio University School of Medicine, Tokyo, Japan.
authors: Akihiro
authors: A
authors: Tanimoto
authors: Department of Otorhinolaryngology, Head and Neck Surgery, Keio University School of Medicine, Tokyo, Japan.
authors: Kaoru
authors: K
authors: Ogawa
authors: Department of Otorhinolaryngology, Head and Neck Surgery, Keio University School of Medicine, Tokyo, Japan. Electronic address: skan@a7.keio.jp.
authors: Sho
authors: S
authors: Kanzaki
authors: Department of Department of Reproductive Biology, National Institute for Child Health and Development, Tokyo, Japan.
authors: Akihiro
authors: A
authors: Umezawa
mesh_terms: D000369:Aged, 80 and over; D000818:Animals; D002460:Cell Line; D003051:Cochlea / Q000166:cytology / Q000601:surgery*; D003287:Contrast Media; D006168:Guinea Pigs; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D008297:Male; D033581:Stem Cell Transplantation / Q000379:methods*; D013234:Stem Cells / Q000166:cytology*; D014183:Transplantation, Heterologous / Q000379:methods
chemical_list: D003287:Contrast Media; D058185:Magnetite Nanoparticles
keywords: Cochlea; Guinea pigs; Magnetic resonance imaging; Mesenchymal stem cells; Superparamagnetic iron oxide; Transplantation