European scientists have developed a new therapeutic approach based on gene therapy, that could provide a new form of sight to patients suffering from degenerative eye diseases such as macular degeneration (MD) and retinitis pigmentosa (RP).
MD and RP are caused by the degeneration of photoreceptors. Researchers from the Institute of Molecular and Clinical Ophthalmology Basel and the German Leibniz Institute for Primate Research (DPZ) successfully re-activated degenerated photoreceptors allowing animal models to see infrared heat signatures without negatively affecting remaining vision.
The team were inspired by bats and snakes which use infrared heat signatures alongside typical vision to hunt prey. This enables bats and snakes to superimpose thermal and visual images in the brain and thus react to their environment with greater precision. To replicate this, the team developed a three-component system. The first element was engineered DNA, ensuring gene coding for the heat-sensitive channel is only expressed in photoreceptors; the second, a gold nanorod that efficiently absorbs near-infrared light; and the third, an antibody to bind the first two together.
Trialling the system on mice with retinal degeneration, the team confirmed near-infrared light effectively excited the photoreceptors and the signal was transmitted to the higher visual centres in the brain. Encouraged by this, co-author, Assistant Professor Arnold Szabo from Semmelweis University in Hungary, tested the model on cultured human retinas, successfully reactivating their visual circuitry.
The study was published in Science.