Scientists have produced new adult neurons from precursor cells by introducing a growth factor into a specific brain region. These techniques are intended to be used in generating new brain cells to replace those lost as a result of injury or disease.
"With a very simple manipulation of the environment, they've created new neurons,"says Ronald McKay, PhD, a neuroscientist at the National Institutes of Health (NIH). "It's impressive."
The studies, in which brain-derived neurotrophic factor (BDNF) was introduced into the adult rat brain, appear in the September 1 issue of The Journal of Neuroscience and were supported in part by the NIH.
In one report, Marla Luskin, PhD and her colleagues at Emory University in Atlanta and Regeneron Pharmaceuticals injected BDNF and a marker to label new cells into an area of the forebrain of adult rats.
A month later they detected an immense number of new neurons in four brain areas where neurogenesis had never been demonstrated in adult animals. New neurons were found throughout parts of the striatum, septum, thalamus and hypothalamus ¯ areas important for cognitive and vital neurological functions.
In another study, Steven Goldman and his colleagues at Cornell University Medical College in New York used viral gene therapy to deliver the gene for BDNF into the forebrain of adult rats. Surprisingly, they found new neurons in the striatum, a region important for the direction of movement.
The cells became the type of neuron typically lost in Huntington's disease. The new striatal neurons were produced for at least three weeks after the injection of BDNF-expressing virus and survived for at least two months thereafter.
"These results suggest that viral gene therapy may be used to restore lost neurons in the adult central nervous system," says Goldman.
BDNF is reduced in parts of the brain of those with Huntington's disease and Alzheimer's disease. These studies indicate that supplementing the adult brain with BDNF not only supports neurons in those brains, but also induces new neurons from precursor cells. Says Luskin: "Thus, if BDNF could be provided exogenously, it could potentially serve to promote the formation of new neurons."
Luskin and Goldman are members of the Society for Neuroscience, an organization of more than 28,000 basic scientists and clinicians who study the brain and nervous system. Luskin can be reached at 404-727-0600 or through Holly Korschun, Emory Health Sciences Communications, at 404-727-3990. Until September 3, Goldman can be reached in Denmark at 011-45-4710-0375; after September 3, he can be reached in New York at 212-746-6572.
The Society publishes The Journal of Neuroscience.