Subthalamic glutamic acid decarboxylase gene therapy: changes in motor function and cortical metabolism.

Publication Type Academic Article
Authors Emborg M, Carbon M, Holden J, During M, Ma Y, Tang C, Moirano J, Fitzsimons H, Roitberg B, Tuccar E, Roberts A, Kaplitt M, Eidelberg D
Journal J Cereb Blood Flow Metab
Volume 27
Issue 3
Pagination 501-9
Date Published 07/12/2006
ISSN 0271-678X
Keywords Genetic Therapy, Glutamate Decarboxylase, Parkinsonian Disorders, Subthalamic Nucleus
Abstract Parkinson's disease (PD) is associated with increased excitatory activity within the subthalamic nucleus (STN). We sought to inhibit STN output in hemiparkinsonian macaques by transfection with adeno-associated virus (AAV) containing the gene for glutamic acid decarboxylase (GAD). In total, 13 macaques were rendered hemiparkinsonian by right intracarotid 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine injection. Seven animals were injected with AAV-GAD into the right STN, and six received an AAV gene for green fluorescent protein (GFP). Videotaped motor ratings were performed in a masked fashion on a weekly basis over a 55-week period. At 56 weeks, the animals were scanned with (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET). Histological examination was performed at the end of the study. No adverse events were observed after STN gene therapy. We found that the clinical rating scores for the two treatment groups had different patterns of change over time (group x time interaction, P<0.001). On FDG PET, the GAD animals exhibited an increase in glucose utilization in the right motor cortex relative to GFP controls (P<0.001). Metabolism in this region correlated with clinical ratings at end point (P<0.01). Histology confirmed GAD expression in treated animals. These findings suggest that STN AAV-GAD is well tolerated and potentially effective in a primate model of PD. The changes in motor cortical glucose utilization observed after gene therapy are consistent with the modulation of metabolic brain networks associated with this disorder.
DOI 10.1038/sj.jcbfm.9600364
PubMed ID 16835631
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