New contributors behind blindness in older adults identified
The University of Maryland School of Medicine (UMSOM) researchers have identified a potential mechanism for age-related macular degeneration, known as the leading cause of blindness among older adults. From their study of laboratory-grown roundworms as well as human and mouse eye tissue, the researchers suggest that the structural organisation of the eye’s light-detecting cells may be affected by the disease – simply because of a genetic mutation.
Several years ago, genetic mutations in the protein complement factor H was identified as a contributor in a large number of macular degeneration cases. Complement factor H protects cells in the body from attack by the immune system; it was thought that macular degeneration was due to the immune system attacking its own body’s cells that went unchecked by complement factor H.
For age-related macular degeneration—a condition that leads to the progressive loss of vision with no known cure – treatment exists for the “wet” version of the disease affecting only 10% of those with the condition. According to the American National Eye Institute, this means most are left with no treatment options.
Assistant Professor of Physiology and scientist Dr. Bruce Vogel, from the UMSOM’s Center for Biomedical Engineering and Technology (BioMET), wanted to find effective new therapies for the disease and studied the disease components in his laboratory model of the roundworm, C. elegans.
Dr. Vogel’s team found a worm version of complement factor H protein located in the middle of sensory neurons that help the worms detect chemicals, food, touch, and temperature. The protein appeared just next to another known important antenna protein, inversin. However, in worms bred to lack complement factor H, they found inversin was spread throughout the antennas rather than remaining in the middle only.
In human retinas, complement factor H and inversin had the same positioning next to each other in the antenna of light-detecting cells from healthy samples. Yet in people with complement factor H mutations (i.e. people genetically predisposed to macular degeneration), they found the inversin spread around, no longer restricted to its neat banding pattern on the antenna.
“Our findings suggest that complement factor H plays a role in maintaining the organisation of photoreceptor cilia (sensory neurons) and this process may be defective in age-related macular degeneration,” said Vogel. “We plan to continue this work to determine how this structural disruption affects vision and to determine whether we can reverse the disruption and restore photoreceptor function.”This will in other words help treat blindness to keep older adults living independently and maintain their quality of life.
Read: New treatment for blindness caused by wet age-related macular degeneration
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