Sight loss caused by damage to the central retina in age-related macular degeneration (AMD) represents the most common cause of irreversible blindness in developed societies. Scientists describe how the mice displayed characteristics of early stage geographic atrophy (withering away). Early stages of geographic atrophy (GA) age-related macular degeneration is characterised by the demise of photoreceptors, which precedes the loss of underlying retinal pigment epithelial (RPE) cells. Sight-loss due to GA has no effective treatment; reflecting both the complexity of the disease and the lack of suitable animal models for testing potential therapies.
To develop a mouse model with reproducible early GA-like features, retinas were exposed an 810 nm diode laser. The effects were assessed by colour fundus photography based on discolouration indicative of retinal atrophy. OCT scans from mice treated with the laser showed rapid development of a geographic atrophic region. An observed development of lesions in 63/80 animals, displayed an overall success rate of 80%.The researchers highlighted that a lack of dry AMD models has previously been one of the factors inhibiting the development of potential new therapies targeting the condition.
Dr Arjuna Ratnayaka, from the University of Southampton, said that the research was the result of multi -disciplinary work between scientists and clinicians over a seven-year period. “These mice could help us understand how AMD causes damage to the retina, which is desperately needed,” he said.“This is important, as it appears that prolonged injections of Vascular Endothelial Growth Factor inhibitors, which is used to manage wet AMD in patients, can sometimes result in a switch to the dry form.”