Cones, the photoreceptor cells responsible for color vision, daylight vision, and detail perception in human eyes, are the focus of the research conducted by scientists Gustavo D. Aguirre and William A. Beltran from the University of Pennsylvania. Their decades-long study of inherited retinal diseases has led to a significant breakthrough: the restoration of cone function by reintroducing a normal or healthy gene into photoreceptor cells.
Both humans and dogs suffer from retinal diseases. In a new daylight vision study, Aguirre and team used a canine model with a mutated NPHP5 gene. Canines with this mutation are born day-blind and lose their night vision over months. This study investigates whether gene replacement therapy with a normal NPHP5 gene could recover cone function and whether a brain scan called functional magnetic resonance imaging (fMRI) can assess the effectiveness of the gene therapy treatment in place of older methods, such as electroretinography and visual behavior tests, which required training dogs for weeks.
Results confirmed that gene replacement therapy in canines with an NPHP5 gene mutation restored brain responses to black-and-white stimulation. The study also showed fMRI could detect brain responses to daylight vision, black-and-white and color information, and measure the degree of daylight vision loss.
What this means for Usher syndrome: The use of this retinal disease model and fMRI to assess disease and treatment status holds significant promise for future retinal disease gene therapy studies. The continued success of these canine studies could lead to similar studies in humans, potentially resulting in the development of clinical trials.
