Carnosine Inhibits Cataract Formation

Results from studies carried out on cultures of eye lens tissue have strengthened previous findings that the dietary supplement carnosine may protect the eyes from cataract formation and partially clear existing cataracts.

Cataracts develop when the main structural protein in the lens, alpha-crystallin, aggregates into clumps that distort and cloud the lens and impair vision. Drawing on previous studies that indicated that carnosine could prevent cataract formation, investigators at the University of Catania (Italy) examined the affect of carnosine on cataract development in vitro and in tissue culture specimens.

The in vitro experiments were conducted on solutions containing bovine alpha-crystallin. Under alkaline conditions, the protein formed cataract-like clumps. Addition of carnosine to the lens protein solution prevented clump formation.

Carnosine has been proven to scavenge reactive oxygen species (ROS) as well as alpha-beta unsaturated aldehydes formed from peroxidation of cell membrane fatty acids during oxidative stress. It opposes glycation and chelates divalent metal ions. While a small number of studies have produced evidence of beneficial effects of N-acetyl-carnosine in treating cataracts, these and other ophthamological benefits had not been proven.

To determine if carnosine's anticlumping activity functioned in living tissue, the investigators treated cell cultures of healthy rat lens tissue with a solution of guanidine or of guanidine mixed with carnosine. Guanidine is a strongly alkaline crystalline compound formed by the oxidation of guanine and found in the urine as a normal product of protein metabolism. It is commonly used in the organic synthesis of plastics, resins, and explosives.

Results published in the May 14, 2009, online edition of the journal Biochemistry revealed that while the guanidine treated lenses became completely cloudy, the guanidine/carnosine lenses developed 50 to 60% less cloudiness. Carnosine also restored most of the clarity when added to lenses that had become clouded. These findings enabled the investigators to conclude that, "The results demonstrate the potential of using carnosine for preventing and treating cataracts.”

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University of Catania