For a long time, the team of scientists was in shock: in just two weeks they had transformed mice that could not walk—into mice that could.
In the latest issue of Stem Cell Reports, available online today, scientists from the University of Utah and the Scripps Research Institute in La Jolla, CA, have reversed the debilitating effects of a multiple sclerosis (MS)-like illness in mice after treating them with human neural stem cells. However, the most astonishing fact, the researchers say, is that they had assumed the treatment wouldn’t work.
The research, which was supported by a CIRM grant when co-senior author Dr. Tom Lane was at the University of California, Irvine, began as a routine experiment to test how the mouse immune system would respond to the transplanted cells. The researchers assumed it would be not unlike how a patient’s immune system reacts to an organ transplant. But the team was surprised by what happened next.
After just two weeks, the mice—who had previously been unable to walk or even feed themselves—had regained basic motor skills. And six months later the improvements have only continued. As co-senior author Dr. Jeanne Loring of Scripps said in today’s press release:
“This result opens up a whole new area of research for us to figure out why it worked. We’ve long forgotten our original plan.”
MS is a debilitating disease in which the body’s own immune system attacks myelin—the protective sheath that surrounds nerve cells. The resulting symptoms vary but many patients experience progressive difficulty walking, impaired vision and fatigue. And while current FDA-approved medications can slow the onset of symptoms, there is still so little that researchers know about the earliest stages of MS that no effective treatment that halts or reverses the symptoms has been found.
But this study’s exciting results could change all that.
After discovering that the stem cell transplant restored the mouse’s ability to walk, the research team looked closer to find out why. As Loring described:
“The way we made the neural stem cells turns out to be important.” [emphasis added]
Normally, human neural stem cells are grown in large quantities in a petri dish prior to transplant. But in this case, Ronald Coleman, the paper’s co-first author, grew fewer cells per dish. This created stem cells that were more ‘potent.’ They predicted that this change would cause the cells to be rejected by the body’s immune system.
But instead, what happened was that the potent stem cells sent chemical signals instructing the mouse’s own cells to regenerate themselves. This serendipitous discovery, said Lane, now at the University of Utah, could end up speeding drug discovery:
“Rather than having to engraft stem cells into a patient, which can be challenging from a medical standpoint, we might be able to develop a drug that can be used to deliver the therapy much more easily.”
For more from Lane on how regenerative medicine offers new hope for patients living with MS, check out our recent videos, Living with Multiple Sclerosis: Hope for Stem Cell Therapies.