"This work shows that stem cells can be used as drug delivery vehicles in the brain," says Svendsen, a professor of anatomy whose laboratory is at the UW-Madison Waisman Center.
The new Wisconsin study, whose lead author is Soshana Behrstock, depended on formative brain cells that were coaxed from blank-slate stem cells. The progenitor neural cells were genetically modified to secrete the growth factor when implanted in the striatum, a large cluster of cells in the brain that controls movement, balance and walking.
To work effectively, the cells in the striatum require dopamine, a chemical that is produced deep in the brain and that travels up nerve fibers to the striatum where it is used to keep critical cells functional. Loss of the ability to produce dopamine is the root cause of Parkinson's, a disease that afflicts about 1.5 million people in the United States.
In the new Wisconsin study, the GDNF-producing cells transplanted in the striatum of animals with a condition like Parkinson's showed not only that a critical drug could be delivered to the right place, but that the drug was delivered in a way that promoted its therapeutic potential. The researchers reported new nerve fiber growth in the striatum and the transport of the critical nerve growth factor GDNF from the striatum to the substantia niagra, the part of the brain that harbors the cells that produce dopamine.
"In Parkinson's, the striatum loses fibers," Svendsen explains. But cells in the striatum exposed to GDNF in the Wisconsin study showed an ability to recover and sprout new fibers.
"It actually seems to work better in the terminal (striatum)," Svendsen says. "The bonus is it gets transported back to the substantia niagra."
The transplanted cells, according to Behrstock, survived and continued to produce GDNF in laboratory animals for up to three months.
One hurdle that needs
Source:University of Wisconsin-Madison