Human stem cells reverse multiple sclerosis in mice

Mice with a viral form of multiple sclerosis (MS) are able to walk again after receiving a transplant of human stem cells, scientists report.

Researchers had injected neural stem cells into the spinal cord of the mice expecting them to be rejected, but instead they witnessed a surprising recovery.

Professor Tom Lane from the University of Utah, who led the research group, said: 'My postdoctoral fellow Dr Lu Chen came to me and said, "The mice are walking". I didn’t believe her'.

The study opens up a new research area for patients with MS, which affects 2.3 million people worldwide. In MS, the body’s immune system targets myelin, the fatty insulation surrounding nerve fibres. This leads to impaired nerve signal transmission, causing widespread symptoms such as loss of vision and motor skills, fatigue, and slurred speech. At present, drugs that dampen the immune system can slow down the early stages of the disease but there is no treatment for patients at the latter stages of MS.

The scientists transformed human embryonic stem cells into neural precursor cells, which have the potential to develop into all the types of cell in the nervous system. Once injected into the mice, they released chemicals that eased the symptoms of MS. This was a result of an unusually low number of neural precursor cells being grown within each lab dish, which meant that more beneficial proteins were released after transplantation.

The exact nature of these proteins remains to be discovered, but the researchers believe that they hold the potential for future treatments.

Professor Lane explained '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'.

Dr Sorrel Bickley, from the MS Society, commented: 'This is an interesting, early-stage study that's given scientists new ideas for future research into potential MS therapies. It's not currently being planned for testing in people, but it's a useful avenue for scientists to explore — we look forward to seeing how this area of research develops'.