
A gene therapy treatment for Parkinsonās disease appears to relieve symptoms by rewiring the brain circuits involved in movement.
People with Parkinsonās disease have tremors and muscle stiffness that are caused by overstimulation of a brain area called the subthalamic nucleus, which is responsible for coordinating the brainās motor regions.
In a trial published in 2011, researchers at the Feinstein Institute for Medical Research in New York found that a gene therapy designed to turn down the activity of the subthalamic nucleus .
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Though the treatment reduced Parkinsonās symptoms for at least a year, it was unclear how. To find out, the researchers have since used PET scans to compare the brains of 15 people who received the gene therapy with 20 who received a placebo.
Reshaping the brain
One year after treatment, the people in the gene therapy group were found to have new brain connections that werenāt seen in the placebo group. Shutting down the disease-causing pathways between the subthalamic nucleus and the brainās motor regions appeared to encourageĀ alternativeĀ pathways to develop instead, says Ā at the Feinstein Institute, who led the study.
These alternative pathways are not found in healthy people. This suggests that gene therapyĀ lets people with Parkinsonās form novel, compensatory brainĀ circuits for controlling movement, says Eidelberg. āWe call it adaptive rewiring.ā
Another treatment for Parkinsonās disease ā called deep brain stimulation ā involves sticking electrodes into the subthalamic nucleus and suppressing its activity using electrical pulses. However, Eidelberg and his colleagues found that this did not lead to the same adaptive rewiring.
The team is now planning a larger trial of gene therapy for Parkinsonās disease that is due to start at the end of 2019.
Science Translational Medicine