This Article was originally posted on the www.lef.org website (Life Extension)

November 26, 2008

Melatonin shows promise against common eye disorder

In the December, 2008 issue of The American Journal of Pathology, Dr Ruth Estela Rosenstein and her colleagues at the University of Buenos Aires and The National Research Council (CONICET) in Argentina report a positive finding for melatonin in an animal model of uveitis. Uveitis is an inflammatory eye disorder characterized in humans by the sudden occurrence of redness and pain which progresses to vision deterioration and, ultimately, blindness if left untreated. The disease can be triggered by eye injury, infection, cancer and autoimmune diseases. Evidence suggests that the damage that occurs in the disease is generated by white blood cells which release cytokines and other inflammatory compounds such as reactive oxygen species. The disorder is currently treated with corticosteroid eye drops, however, the treatment can increase the risk of glaucoma when used long term.

In their article entitled "Therapeutic Effect of Melatonin in Experimental Uveitis," Pablo Horacio Sande et al report the results of subcutaneous administration of melatonin to hamsters in which uveitis was induced. The team found that tumor necrosis factor-alpha and nuclear factor kappa-beta, factors that contribute to inflammation, were reduced compared to levels measured in animals that received no melatonin. Also reduced were such symptoms including blood vessel dilation, inflammation and cataract. Melatonin additionally was shown to help protect the integrity of the blood-ocular barrier. "Melatonin, which lacks adverse collateral effects even at high doses, could be a promising resource in the management of uveitis," the authors write. "Alone or combined with corticosteroid therapy, the anti-inflammatory effects of melatonin may benefit patients with chronic uveitis and decrease the rate and degree of corticosteroid-induced complications."

"Even as preventive strategy, the present results suggest that melatonin, a very safe compound for human use, should be included in the ophthalmic therapeutic resources," they conclude.

—D Dye