A summary of all 11 studies, plus the results of the meta-analysis of their pooled data, can be found in a paper published in the 19 December online issue of the journal Science Translational Medicine.
Co-lead author of the paper Yang (Ted) Teng is a Harvard Medical School (HMS) associate professor of surgery at Brigham and Women's Hospital in Boston, Massachusetts, in the US. He and his colleagues believe the key to treating ALS lies in targeting new mechanisms uncovered by studies into neural stem cells.
Their review takes in a decade of research from several institutions. As well as Brigham and Women's, it covers results from studies conducted at Johns Hopkins University, the VA Boston Healthcare System, Boston Children's Hospital, Sanford-Burnham Medical Research Institute, UMass Medical School, SUNY-Syracuse, and Columbia University.
Teng says in an HMS statement released last week:
"This significant research will help us better understand the mechanisms underlying motor neuron diseases."
ALS and Neural Stem CellsIn ALS, also known as motor neuron disease or Lou Gehrig's disease, the nerve cells in the spinal cord die, gradually causing the person to lose their ability to move and eventually, breathe.
Neural stem cells are the precursors of all brain cells. They can self-renew, make more neural stem cells and differentiate into nerve cells or other brain cells. They can also rescue nerve cells that don't work properly and help preserve and regenerate brain tissue.
What the Evidence ShowsThe accumulation of evidence that Teng and colleagues reviewed shows that transplanting neural stem cells (both mouse and human) into various levels in the spinal cords of mice bred to have familial ALS, slowed the disease down, and improved motor function and breathing. Also, 25% of the treated mice lived three to four times longer than untreated mice.
"This work sheds new light on detrimental roles played by non-neuronal cells in triggering motor neuron death, and these events should be targeted for developing more effective therapeutics to treat ALS."
Neural Stem Cells Boost Remaining Nerve CellsThe treatment works not for the obvious reason that the transplanted neural stem cells replace nerve cells missing from the spinal cords of mice with ALS. Their biggest contribution comes from a series of protective molecules that trigger the host cells to produce their own protective molecules.
Thus the transplanted neural stem cells boost the health and function of nerve cells that still remain, and they also reduce inflammation and the number of toxin-producing, disease-causing cells.
The researchers were thus surprised to find that the biggest contribution the neural stem cells have in terms of clinical benefit, does not come from replacing damaged or missing cells, but from improving the host environment and protecting endangered nerve cells.
Teng points out the treatment does not cure ALS: the research shows the potential that mechanisms used by neural stem cells have for improving the quality and length of life of people with ALS.
Funds for the studies that Teng and colleagues reviewed came primarily from Project ALS, the Christopher Reeve Foundation/American Paralysis Association, the California Institute for Regenerative Medicine, the National Institute of Neurological Disorders and Stroke, the Sanford Children's Research Center, the A-T Children's Project and the Zinberg Foundation.
Teng himself also received grants from VA Biomedical Research and Development and VA Rehabilitation Research and Development, and the National Institutes of Health (NIH).
In October 2012, we also heard news of how scientists in the US may have found a new treatment target for ALS, with the help of baker's yeast.