Neural stem cells were shown to be effective against amyotrophic lateral sclerosis (ALS), or motor neurone disease, in 11 independent studies on mice with the disease. In the research, stem cell injections into the rodents' spinal cords slowed disease onset and progression, improved motor function, and significantly prolonged survival.
The studies are grouped together in a meta-analysis published in Science Translational Medicine.
Dr Ted Teng, associate professor of surgery at Brigham and Women's Hospital in the USA, and one of the principal investigators, stressed that the technique was 'not a cure for ALS', but added that the research 'shows the potential that mechanisms used by neural stem cells in our study have for improving an ALS patient's quality of life and length of life'.
Neural stem cells normally develop into the specialised cells of the nervous system. The 11 studies grouped in this paper were performed over the last ten years. Professor Evan Snyder of the Burnham Institute in the USA, one of the study group leaders, told KUHF FM: 'In the early days we thought, "well, stem cells should simply replace these dying motor neurones"'.
But the benefits in the mouse experiments were shown to come from other mechanisms. Professor Snyder told KUHF FM that the stem cells appear to work by two methods: 'A: protecting [healthy] neurones and their connections from dying. B: crowding out or suppressing the cells that may be causing the disease and also getting rid of a lot of inflammation, making growth factors, making the cells that were there actually healthier'.
replacement plays a surprisingly small role' in the benefits afforded by neural stem cells, said Professor Snyder.
And the benefits were considerable. In the study performed by Professor Snyder's team the ALS mice lived three to four times longer than their untreated counterparts.
However, whether such improvement will translate to patients in a clinical situation remains to be seen. A clinical trial to test neural stem cells in ALS patients began at the end of 2011. Initial results were encouraging (reported in BioNews 651) but the study is still in its earliest phase.
Currently there is no cure for ALS and little effective treatment. ALS is a progressive, late-onset neurodegenerative disorder where the brain's ability to relay signals to the muscles is compromised. This leads to loss of voluntary muscle movement, and ultimately paralysis and respiratory failure. ALS affects around one in every 50,000 people.