Gene Therapy Restores Sight

This mouse is blind. Slowed down by water for proper observation, the mouse can't find its way towards light.

It suffers from Retinitus Pigmentosa, a genetic disease that affects the eye's ability to communicate with the brain. The disease affects an estimated two million people in the United States alone.

Alan Horsager, a professor of neuroscience at USC, is using an experimental gene therapy that delivers light-activated proteins to the cells of the mouses' retinas. He's hoping the proteins will create new photoreceptor cells which will allow the mouse to see.

He doesn't have to wait long before the mouse begins to respond exactly as intended.

[Alan Horsager, Neuroscience Professor, University of Southern California]:

"What we find is that these mice that are originally blind, these are models that represent retinitis pigmentosa in people, actually have restored visual function."

The success of the experiments has spurred Horsager to form EOS Neuroscience - a company that aims to commercialize treatment for people who suffer from retinal disease. The treatment is based on optogenetics - an emerging field of research that uses light to control genetically engineered cells.

Ed Boyden, an assistant professor at MIT, is one of the pioneers of optogenetics. His specialty is the study and potential control of neurons, the cells that comprise the brain.

[Ed Boyden, Assistant Professor, Massachusetts Institue of Technology]:

"What we like to be able to do and what we have started to be able to do is to use light to turn on and off each of these regions and then pathways and cell types within those pathways in order to figure out how they work together. So we turn something off we can figure out what it was needed for, we have deleted it and we can assess its necessity. And by stimulating something we can figure out what its power could be, what it could do causally to its neighbors."

In his lab he uses rats to show that by engineering neurons to become sensitive to light, he can target and control different parts of their brains.

Ultimately, he says, his research will be applicable to humans.

The human brain is made up of billions of neurons, all inter-connected to form a complex network that scientists are just now starting to understand.

[Ed Boyden, Assistant Professor, Massachusetts Institute of Technology]:

"If we think about the complexity of the brain, only a very small portion has been studied in very great detail. What we would like to do is really reveal the principles of how to control these circuits to fix their problems when they go awry."

Boyden says optogenetics could eventually lead to treatments or even cures, for neurological disorders like Parkinson's and Alzheimer's.

While the research is still in its infancy, Alan Horsager believes that optogenetics has the potential to restore vision in people, as it has in his lab mice, in the near future. He hopes to start clinical trial on humans in a couple of years.

Both he and Ed Boyden believe that curing some forms of blindness will be the first of many benefits to come from this emerging field.