The olfactory bulb, the center of smell detection, houses numerous primitive stem cells that normally feed the constant, life-long regeneration of odor-detecting nerves. Because they are found in a fairly accessible region of the brain and could conceivably be removed from a person's olfactory bulb without causing permanent damage, adult olfactory bulb stem cells are a potential non-embryonic source for cells that could prove useful in replacing nerve cells lost due to injury or diseases like ALS and Parkinson's.
Researchers Zhiping Liu, Ph.D., and Lee Martin, Ph.D., who have carefully characterized cells from the olfactory bulb in people, rats and mice, grew clusters of neuronal stem cells taken from the olfactory bulb of normal mice and froze them. Retrieved cells were then transplanted into the spinal cords of genetically engineered mice that develop the equivalent of ALS.
Animals that got the transplanted cells did develop disease symptoms, but did so about a month and a half later than non-transplanted animals (137 days versus 90 days of age, on average). Treated mice also lived about two months longer than untreated mice, who were euthanized at roughly 137 days because of their disease.
"These transplants significantly prolonged the animals' lives by becoming neurons and probably also by influencing existing nerve cells," says Martin, an associate professor of pathology and neuroscience at Johns Hopkins. "The transplants definitely provided a functional improvement, and we're hopeful about the potential of these adult neuronal stem cells in treating ALS some day. But there is a great deal of laboratory work to do before clinical trials would be appropriate."
The research was funded by the ALS Association.
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