Topical chelation therapy shown to be potential treatment for diabetic cataracts
FORT LAUDERDALE, Fla. — A topical chelation therapy was effective in reducing excess intraocular metals that are known to contribute to the formation of diabetic cataracts, according to a poster presentation at the Association for Research in Vision and Ophthalmology meeting here.
Naseem H. Ansari, PhD, and colleagues at University of Texas Medical Branch described measures to reduce excess metals and treat or prevent diabetic cataract in a rat model.
Research has determined that transition metal ions play a role in generating reactive oxygen species, which increase oxidative stress and cause pathologies such as diabetic cataract, the study authors said.
"Elevated levels of chelatable pool of redox-active metal ions have indeed been shown to be present at increased concentrations in aged and cataractous lenses," they said. "However, metal chelation attempts to prevent cataractogenesis have been limited due to the permeability barrier of the cell membrane to the metal chelators."
To study the efficacy of chelation in preventing cataract, investigators used EDTA, a topical chelator, combined with methylsulfonylmethane (MSM), a permeability enhancer.
In a rat study, investigators applied topical EDTA combined with MSM. They applied various concentrations of EDTA and MSM to assess the effectiveness of the combination in preventing or diminishing diabetic cataract.
The first leg of the study showed that EDTA and MSM enters the aqueous humor and lens. The second leg showed a "significant amelioration" of cataract formation, the authors said.
"Oxidative markers, which were increased in the diabetic rat lens, significantly normalized in the lenses of the diabetic rat that were treated with EDTA+MSM," they said.
"EDTA in the presence of MSM can enter into the lens when topically applied onto the eye," they said. "Furthermore, it appears that 'excess metals' in diabetes trigger the oxidative stress and contribute to cataractogenesis. Chelation therapy using EDTA+MSM can be a promising clinical therapy for protecting against diabetic cataracts."