Age-related macular degeneration (AMD) is the leading cause of blindness among seniors. Researchers from the University of Fribourg, part of a team led by Professor Patricia Boya, working with the Center for Biological Research Margarita Salas (CSIC) in Spain, have shown that the natural compound urolithin A can alleviate degeneration and preserve visual function.

Macular degeneration is a visual disorder that affects patients’ ability to see details. In particular, it can result in the loss of central vision, i.e., the center of whatever the eye is focused on. It is the principal cause of visual impairment for persons over 50. Given the aging population of the developed world, the disorder could afflict twice as many people in 2040 as today.

Programed obsolescence
The retina is the part of the eye that detects light and requires a lot of energy to work. That energy comes mostly from mitochondria, the tiny powerhouses inside the cells making up the retina and the retinal pigment epithelium (RPE). As we age, mitochondria function less effectively, especially due to the damage done by light striking the retina. “Not only do they produce less energy, they are no longer able to clean out cellular waste,” the University of Fribourg Professor Patricia Boya explained. “That change leads to the build-up of protein aggregation,” that is, proteins accumulating and clumping together, “and defective mitochondria, causing intercellular collapse, which triggers the death of RPE, and that eventually leads to vision loss.” The discovery of this mechanism, observed in mice, was the focus of a paper published in the journal Molecular Neurodegeneration.

Study of mice
This is not all. The scientists were also able to demonstrate that urolithin A, a natural compound found in several kinds of fruit, especially pomegranates, can serve as a neuroprotector. “We have observed in mice that urolithin A enables cells to reestablish autophagic flux, in other words, it restarts the cells’ own cleaning process.” Professor Boya excitedly pointed out. This treatment helps photoreceptors to work properly while preventing vision loss in mice suffering from AMD. The discovery offers interesting prospects for treating age-related disorders like AMD or even Alzheimer’s disease.

Urolithin A promotes p62-dependent lysophagy to prevent acute retinal neurodegeneration, BMC, 18.06.2024