RespiteMatch.com Health Blog

Human stem cells transplanted into injured mice help them walk again, suggesting human treatments are nearer.
September 20, 2005

California researchers have successfully transplanted human neural stem cells into mice with spinal cord injuries and demonstrated improvements in the animals’ ability to walk, suggesting future human treatments are a little bit closer, a leading scientific journal reported Tuesday.

The study, funded by the Christopher Reeve Foundation, was published in the online edition of the journal, Proceedings of the National Academy of Sciences of the United States of America (PNAS).

“These data suggest that hCNS-SCns [human CNS stem cells grown in a particular way] may possess therapeutic potential for CNS injury and disease,” said the paper.

The study showed that human neural stem cells can not only survive transplantation in mice, but can also integrate into their injured spinal chords.

In particular, the data is the first to show that transplanted, human neural stem cells can regenerate the fatty insulating sheath (called a myelin sheath), which is essential to their proper function.

‘The design of this study raises the bar.’

-Martin McGlynn,

StemCells

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“Mice that received these stem cells nine days after spinal cord injury showed improvements in walking ability compared to mice that received either no cells or a control transplant of fibroblast cells,” said Susan Howley, director of research for the Christopher Reeve Paralysis Foundation.

“Sixteen weeks after transplantation, the human cells were killed by injection of a diphtheria toxin,” she added. “As a result, the improvements in walking were abolished, which suggests that the transplanted human neural stem cells are needed to maintain recovered function.”

Human Treatments Still Distant

Menlo Park, California-based Geron, widely accepted as one of the companies furthest along in this research worldwide, has spent more than $100 million on academic research at the University of California in San Francisco, the University of Wisconsin, the University of Edinburgh, and Johns Hopkins University (see Stem Cells: U.S. May Lose Lead).

New treatments to regenerate human spinal cords and potentially cure spinal injury patients are still a long way off, however.

The researchers behind this study, including those from StemCells in Palo Alto, California, were excited about the results but were careful to avoid overstating the findings.

“While we are early in our quest to find a stem cell therapy for spinal cord injury, the design of this study raises the bar,” said Martin McGlynn, chief executive of StemCells.

“These findings suggest that hCNS-SCns could have potential benefits for multiple central nervous system diseases and injuries,” said the paper. “However, this study represents an initial step toward defining potential clinical applications. Additional animal studies are necessary both to establish the mechanism[s] of recovery and to evaluate the potential of these cells for possible therapeutic use.”