Therefore, some strategies for treating these diseases have focused on gene therapydelivering DNA sequences that can enter cells and produce the needed enzyme. Researchers have also sought to deliver gene therapy directly to the brain rather than to the bloodstream, but there are practical limitations to making multiple injections into a childs brain.
In the current study, Wolfe targeted a particular region of the mouse brain called the ventral tegmental area (VTA), which has numerous connections with the rest of the brain. He used a neutralized virus called adeno-associated virus (AAV) as a vectorthe delivery vehicle for the gene that carries coded instructions to produce the desired enzyme.
We found that one subtype of AAV was particularly effective for transporting the gene, said Wolfe. The neural pathways carried the virus throughout the brain, where the gene produced the enzyme. The enzyme then cleaned up the storage lesions to the point that these storage lesions were indistinguishable from those found in the brains of normal mice. One advantage of lysosomal enzymes, said Wolfe, is that cells receiving the delivered gene secrete beneficial enzymes to neighboring cells, creating a sphere of correction.
The level of correction resulting from a single injection was unprecedented, said Wolfe, but he cautioned that direct human treatments might be years away. In future studies, he will investigate whether this technique is effective in animals larger than mice. Such results might conceivably resemb
|Contact: John Ascenzi|
Children's Hospital of Philadelphia