"We were extremely surprised to see that the grafted stem cells were not negatively affected by the degenerating cells around them, as many feared introducing healthy cells into a diseased environment would only kill them," says Vassilis Koliatsos, M.D., an associate professor of pathology and neuroscience at Hopkins.
Although all the rats eventually died of ALS, Koliatsos believes his experiments offer "proof of principle" for stem cell grafts and that a more complete transplant of cells - already being planned -- along the full length of the spine to affect upper body nerves and muscles as well might lead to longer survival in the same rats.
"We only injected cells in the lower spine, affecting only the nerves and muscles below the waist," he noted. "The nerves and muscles above the waist, especially those in the chest responsible for breathing, were not helped by these transplanted stem cells."
The research team used so-called SOD-1 rats, animals engineered to carry a mutated human gene for an inherited form of ALS. As in human ALS, the rats experience slow nerve cell death where all the muscles in the body eventually become paralyzed. The particular SOD-1 rats in the study developed an "especially aggressive" form of the disease.
Adult rats not yet showing symptoms were injected in the lower spine with human neural stem cells - cells that can in theory become any type found in the nervous system. As a comparison, the researc
Source:Johns Hopkins Medical Institutions