Washington: A drug prescribed for diabetes could also have another important use: treating one of the world`s leading causes of blindness.
In lab rat and cell-culture experiments, scientists found that metformin, which is commonly used to control blood sugar levels in type 2 diabetes, also substantially reduced the effects of uveitis, an inflammation of the tissues just below the outer surface of the eyeball.
Uveitis causes 10 to 15 percent of all cases of blindness in the US, and is responsible for an even higher proportion of blindness globally. The only treatment now available for the disorder is steroid therapy, which has serious side-effects and cannot be used long-term, the journal Investigative Ophthalmology & Visual Science reports.
"Uveitis has various causes - the most common are infectious diseases and autoimmune disorders - but they all produce inflammation within the eye," said University of Texas Medical Branch-Galveston, professor Kota V. Ramana, senior study author. "Metformin inhibits the process that causes that inflammation," added Ramana.
The scientists discovered metformin`s efficacy when they tested it in rats given an endotoxin that mimicked the inflammatory effects of bacterial infection. The results showed clearly that metformin was a very effective anti-uveitis agent, according to a Texas statement.
"We found that the drug is therapeutic as well as preventive - if we gave our rats the drug beforehand, they didn`t develop uveitis, and if we gave it after uveitis had developed, it was therapeutic," said Texas professor Satish Srivastava, Texas professor and study co-author. "Metformin`s strong anti-inflammatory properties make this possible."
Because metformin is already used so widely as a therapy for diabetes, the UTMB scientists believe that it has a good chance of being rapidly opted as an anti-uveitis drug.
"I think after a few more pre-clinical studies are done, we can get this drug to patients in a shorter time than usual," Ramana said. "Its safety is already known, so all that we need to see is its efficacy in humans."