@misc{oai:repo.qst.go.jp:00069618,
 author = {Odaka, Kenichi and Aoki, Ichio and Moriya, Junji and Tateno, Kaoru and Tadokoro, Hiroyuki and Minamino, Tohru and Irie, Toshiaki and Komuro, Issei and Kanno, Iwao and 小高 謙一 and 青木 伊知男 and 森谷 純治 and 舘野 馨 and 田所 裕之 and 入江 俊章 and 菅野 巖},
 month = {Sep},
 note = {Presentation Number 1034
\nIn-Vivo Application of Manganese-Labeled Immunocytes
\nKenichi Odaka1, Ichio Aoki1, Junji Moriya2, Kaoru Tateno2, Hiroyuki Tadokoro3, Tohru Minamino2, Toshiaki Irie1, Issei Komuro2, Kanno Iwao1, 1National Institute of Radiological Sciences, Japan; 2Chiba University, Japan; 3Tokai University, Japan. Contact e-mail: odaka@nirs.go.jp
\nOBJECTIVES: Recently, iron-oxide nanoparticles allows in-vivo trafficking of transplanted cells such as phagocyte and neural stem cell using magnetic resonance imaging (MRI). Although iron-oxide nanoparticles provide excellent sensitivity and contrast, it is difficult to label for non-phagocyte such as immunocyte due to size of the particle. On the other hand, although manganese (Mn) has poor sensitivity than the iron-oxide nanoparticles, Mn can provide positive contrast on T1-weighted MRI as a result of T1 (longitudinal relaxation time) shortening. In addition, most of cells are easily labeled by Mn because Mn2+ can pass the divalent calcium-ion channel. Therefore, we evaluated whether Mn-labeled cells can provide enough positive enhancement for cell tracking in-vitro and in-vivo. MATERIAL AND METHODS: Immunocytes of rat were separated from whole blood using centrifugation. Then they were incubated with MnCl2 for labeling. Ischemic models of the lower limbs were prepared 6 hours before cell injection in the rats. The labeled cells were topically injected into the ischemic left leg of the rats. Saline was also topically injected into the ischemic right leg as a control. MRI measurements were performed using 7.0 Tesla horizontal MRI immediately, 24 hours, and 48 hours after the injection. RESULTS: Immediately after the injection, both Mn-labeled cells and saline provide signal reduction on the T1-weighted MRI. At 48 hours after injection, Mn-labeled cells were detected as a double layered structure which has a positive outline and negative core, although injected saline was disappeared. Regeneration of blood flow was better in the immunocytes transplanted side than in the control. CONCLUSION: This study describes a novel contrast agent for transplanted immunocytes with the capability of the measurement of the transplanted area. In addition, it also can provide enough T1-positive MRI signal for tracing immunocytes and may be suitable for in-vivo trafficking of ischemic disease and regeneration researches.
\nDisclosure of author financial interest or relationships:
\nK. Odaka, Japan Cardiovascular Research Foundation, Grant/research support; I. Aoki, None; J. Moriya, None; K. Tateno, None; H. Tadokoro, None; T. Minamino, None; T. Irie, None; I. Komuro, None; K. Iwao, None., 2008 World Molecular Imaging Congress},
 title = {In-Vivo Application of Manganese-Labeled Immunocytes},
 year = {2008}
}