January 7, 2020
Keio University School of Medicine
National Institutes for Quantum and Radiological Science and Technology
Japan Agency for Medical Research and Development
A group led by Professor Hideyuki Okano of the Department of Physiology and Professor Masaya Nakamura and Assistant Professor Yunosuke Tanimoto of the Department of Orthopaedic Surgery at the Keio University School of Medicine, along with Tomoteru Yamasaki, principal investigator, and Ming-Rong Zhang, Department Head, of the Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology (hereinafter "QST"), has succeeded for the first time in the world in detecting in vivo tumorigenic changes, a concern in transplantation therapy using iPS cells. This was achieved by imaging undifferentiated cells in model mice transplanted with human iPS cell-derived neural stem/progenitor cells using clinically applicable positron emission tomography (hereinafter "PET").
Previously, the Keio University School of Medicine has reported improvements in motor function after transplanting human iPS cell-derived neural stem/progenitor cell spheres (neurospheres) into spinal cord injury model animals.
However, in some tumorigenic cell lines, undifferentiated properties persist for a long period after transplantation, and undifferentiated neural cells tend to proliferate. Therefore, to ensure post-transplantation safety, a technology that can continuously monitor for tumor formation and cell proliferation has been desired. It is believed that if transplanted cells could be monitored in vivo through minimally invasive diagnostic imaging, it would be possible to detect dangerous tumorigenic changes early and take countermeasures such as resection of the lesion. However, to date, no clinically applicable imaging technology capable of visualizing tumorigenic changes in transplanted cells has been reported anywhere in the world.
In this study, the research group successfully detected in vivo tumorigenic changes in undifferentiated neural tissue remaining in the brains and spinal cords of mice after transplantation of human iPS cell-derived neural stem/progenitor cells, using an imaging technology that can observe the functional information of molecules in vivo.
The results of this research are expected to be useful as an in vivo cell monitoring technology for observing the clinical course after transplantation of human iPS cell-derived neural stem/progenitor cells in patients with spinal cord injury, traumatic brain injury, and other conditions. This can be considered a major achievement toward establishing safer regenerative medicine.
These research findings were published in "STEM CELLS Translational Medicine" on January 6, 2020 (US Eastern Time).
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