Cataracts – or a clouding of the lens of the eye – is one of the leading causes of vision loss around the world, and can only currently be treated by surgery to replace the eye lens.
According to researchers writing in the July 28 edition of the American Chemical Society journal Biochemistry, their tissue culture experiments demonstrated that carnosine could help prevent cloudiness on eye lenses, and could also restore clarity to clouded lenses.
Cataracts develop when the main structural protein in the lens, alpha-crystallin, forms abnormal clumps. The clumps make the lens cloudy and impair vision. Previous studies hinted that carnosine may help block the formation of these clumps.
Italian researcher Enrico Rizzarelli and his colleagues extracted eye lenses from one-month old healthy rats killed in a CO2 gas chamber. Rat lenses were organ cultured in a protein-free medium in a cell culture incubator.
The researchers then prepared solutions of L-carnosine and guanidine, which is a substance known to form cataracts. They exposed the tissue cultures to either guanidine or a combination of guanidine and carnosine.
Clearing the clouds
Their findings revealed that the guanidine lenses became completely cloudy, while the guanidine/carnosine lenses developed 50 to 60 per cent less cloudiness.
Carnosine also restored most of the clarity to clouded lenses, they said, prompting them to suggest that carnosine could hold potential for preventing and treating cataracts.
“In this study, we observed that considering α-crystallin alone or the more complex model of lens organ culture, the presence of carnosine prevented fibril formation by denaturant and heat stress and disassembled already formed fibrils, restoring almost completely the lens transparency,” write the researchers.
“Moreover, we show that the self-assembly of α-crystallin into amyloid fibrils determines a loss of its chaperone activity and that the carnosine protective effect is important for restoring the anti-aggregating activity of α-crystallin.”
Source: Protective Effects of l- and d-Carnosine on α-Crystallin Amyloid Fibril Formation: Implications for Cataract Disease
Biochemistry, 2009, 48 (27), pp 6522–6531
Authors: Francesco Attanasio, Sebastiano Cataldo, Salvatore Fisichella, Silvia Nicoletti, Vincenzo Giuseppe Nicoletti, Bruno Pignataro, Anna Savarino, Enrico Rizzarelli