A team of researchers from several Japanese universities announced they have been successful in repairing the damaged spinal cords of mice using iPS (induced pluripotent stem) cells. The treatment, though complex and lengthy, holds out hope to those who have suffered spinal cord injuries causing varying degrees of paralysis.
The researchers, led by professor Hideyuki Okano of Keio University and professor Shinya Yamanaka of Kyoto University (top), recently published the results of their experiments in the online version of the Proceedings of the National Academy of Sciences of the United States of America (PNAS).
"With strict evaluation of the safety of iPS cells, the path to using them in the future to treat spinal cord injuries has been opened," said professor Okano in a prepared statement. The safe use of iPS has long been a goal of researchers worldwide, as these types of stem cells are sourced from adult cells and not human embryos.
The greatest problem in using iPS for medical applications is that the cells can grow uncontrollably, causing tumors in the areas to be treated. The Japanese team got around this roadblock in a novel way: iPS were transplanted into the brains of mice and their growth was monitored closely for up to 6 months.
Then the researchers harvested 500,000 of the cells that had not formed tumors, and injected them into the damaged spinal cord of a mouse 9 days after its injury. The subject mouse, which had lost all mobility in its hind legs, soon recovered the ability to use its legs.
The treatment poses a number of problems should it be extended to humans sometime in the future, most notably the part about growing the iPS cells in "a brain" for 6 months.
Then again, certain shortcuts and liberties were taken by the Japanese team because the test subjects were lab mice - the main point to be proved was whether this type of treatment could be effectual. Further research will refine the steps involved so that treating human subjects can be made practicable. (via Mainichi Daily News and Gladstone/UCSF)