In simple terms, genes are like recipes for making proteins. All the cells in our bodies “read” genetic information so they can make the critical proteins necessary to stay healthy and function properly. If there is a mistake in a gene — that is, a misspelling — a protein might not be made correctly and cells in the retina might degenerate and cause vision loss.
These misspellings are called mutations, and just like a mistake in a recipe, some mutations are more devastating than others. For example, when baking a cake, let’s say there is an error in the recipe. It incorrectly calls for a quarter cup of sugar, when the right amount is a half of a cup. The cake may not taste great, but it is still edible. But let’s say the instruction for adding flour is omitted entirely. Then the cake will be a complete failure and go uneaten.
An image of an electrically connected patch of one single class of retinal neurons that signal brightness for the visual system. Each single cell is shaped like a spider or octopus and connected to its neighbors. This is the first visualization of such a population of cells that has been untangled from the complete connectome.
In simple terms, the retina is a thin, delicate layer of tissue lining the back of the eye that captures light like film or digital sensors in a camera. But the retina is actually an incredibly complex network of hundreds of millions cells that process light, converting it into electronic signals, which are sent to the brain and used to create the images we see. And, understanding the pathways of this gargantuan network — and how they are rewired with aging and disease — is helpful in trying to save and restore vision.
“If you are going to fix cells in the retina, you have to know how they communicate,” said Robert E. Marc, Ph.D., University of Utah, in the opening keynote lecture at the RD2016 meeting in Kyoto, Japan. Held September 19-24, RD2016 is the largest research conference dedicated exclusively to retinal degenerations, and funded in part by the Foundation Fighting Blindness.
Inherited retinal diseases are difficult to understand merely because they’re so rare and diverse. More than 250 genes, when mutated, can cause them, yet collectively, they affect only 200,000 people in the United States.
Their widely varying impact on vision adds to the challenge. For example, the youngest sibling in a family may be nearly blind from retinitis pigmentosa (RP), while his or her older brother or sister with the same RP gene mutation can have near normal vision.
But as FFB-funded retinal geneticist Stephen Daiger, Ph.D., discussed at the RD2016 meeting in Kyoto, Japan, the complex and elusive nature of these conditions can also extend to the way they are passed down in families, making diagnosis and prognosis quite challenging. Dr. Daiger was one of nearly 300 retinal researchers who gathered September 19-24, 2016, for the world’s largest conference focused exclusively on retinal degenerative diseases. The conference was supported in-part by FFB.
William Beltran, Artur Cideciyan, Gustavo Aguirre and Samuel Jacobson. Photo by John Donges/Penn Vet
When scientists embark on developing a treatment for an inherited retinal disease, one of their first tasks is to identify or create a model of the condition. Disease models can be cells in a Petri dish, a genetically engineered mouse or rat, or larger animal such as a pig. Each type of model has its pros and cons, including cost and similarity of disease characteristics to those in humans.
The investigators then use the model to study how vision is lost — that is, they figure out which types of retinal cells degenerate, what is causing the degeneration, and how quickly the cells stop working. After they gain an understanding of the disease, researchers evaluate potential therapeutic approaches using the model as a testing platform.
The goal: Move a therapy into a human study.
RetroSense Therapeutics has reported that three participants have received injections of its potential optogenetic therapy, known as RST-01, in a Phase I/II clinical trial. The patients were given the lowest dose of RST-01, and no adverse ocular events were observed. Furthermore, the treatment showed some biological activity, though RetroSense did not provide details about what that activity was or what it meant.
More information on safety and efficacy will likely be reported about the RetroSense trial after more trial participants have been observed over a longer period of time, and after discussions with the U.S. Food and Drug Administration. Continue Reading…
In a post at asharedvision.com, artist Dana Simon describes her experience with My Retina Tracker, a free and secure online registry for people with inherited retinal diseases. My Retina Tracker provides researchers with invaluable information that helps them study retinal diseases, and informs patients when their profile matches clinical-trial criteria. Examples of Dana’s artwork can be found on her website.
An emerging stem-cell-derived treatment designed to preserve and potentially restore vision in people with retinitis pigmentosa (RP) has demonstrated a favorable safety profile in an ongoing Phase I/II clinical trial at the University of California, Irvine. The therapy is being developed by the regenerative medicine company jCyte with trial funding from the California Institute for Regenerative Medicine. Earlier research funded by the Foundation Fighting Blindness helped advance this therapeutic approach toward a human study.
Given this trial is one of the first-ever for a stem-cell-derived therapy for RP, this safety report is good news and an important step in the right direction. We at the Foundation look forward to additional reports from this study in the coming years as the trial advances.
Almost from the start, the cards were stacked against Dartanyon Crockett. He was diagnosed, at an early age, with Leber’s disease, which caused him to be legally blind. At the age of 8, he lost his mother. And by middle school, he was relentlessly teased for being visually impaired.