Gene Therapy Makes Near-Blind Patients See by Strengthening Neural Connections

A gene therapy trial restored vision to many Leber’s Congenital Amaurosis Type 2 (LCA2) patients who would normally go blind. Although reviving the retina was one key to restoring sight, the new study showed the gene therapy also prompted the brain to rewire, strengthening the visual pathway.
As this occurred even in a patient in her 40s, it means the brain is more plastic than was known. “For many years, most of the focus on brain properties has been on the cortex, activation in the grey matter, because that is what neuroscientists typically measure with their electrodes,” Brain Wandell, Ph.D., director of Stanford University’s Center for Cognitive and Neurobiological Imaging, told Drug Discovery & Development.
“Finally, somebody has looked at white matter properties, at the critical axons, and specialized cells and glia wrapped around those axons. Finally, they have established a confluence between white matter and gene therapy.” Wandell was not involved in the new study.
National Institutes of Health Nervous System Development and Plasticity Section Chief R. Douglas Fields, Ph.D., was also uninvolved in the new study. He agrees it is critical to look at oft-overlooked white matter in human brain studies. Mice don’t cut it. Only 10 percent of the mouse brain is made of white matter, versus half of the human brain.
“This study is significant in many respects,” Fields told Drug Discovery & Development.