New avenue to treat diabetes-related vision problems

PUBLIC RELEASE DATE:

21-Jan-2014

Contact: Quinn Eastman qeastma@emory.edu 404-727-7829 Emory Health Sciences

Dopamine-restoring drugs already used to treat Parkinson's disease may also be beneficial for the treatment of diabetic retinopathy, a leading cause of blindness in adults, researchers have discovered.

The results were published in the Jan. 15 issue of Journal of Neuroscience.

Diabetic retinopathy affects more than a quarter of adults with diabetes and threatening the vision of more than 600,000 people in the United States.

Doctors had previously thought most of the impairment of vision in diabetic retinopathy came from damage to the blood vessels induced by high blood sugar, but had known that dopamine, a vital neurotransmitter in the brain, was also important in the retina.

"There was some evidence already that dopamine levels were reduced in diabetic retinopathy, but what's new here is: we can restore dopamine levels and improve visual function in an animal model of diabetes," says Machelle Pardue, PhD, associate professor of ophthalmology at Emory University School of Medicine and research career scientist at the Atlanta VA Medical Center.

The first author of the paper is MD/PhD student Moe Aung. Senior authors are Pardue and P. Michael Iuvone, PhD, professor of ophthalmology and pharmacology and director of vision research at Emory Eye Center.

Aung and his colleagues examined mice that were made diabetic by treating them with streptozocin, which is toxic to insulin-producing cells in the pancreas. By injecting the mice with L-DOPA after getting streptozocin, the researchers could delay the appearance of visual problems by weeks and lessen the severity of the visual defects. Researchers also found that the visual benefits of L-DOPA originated from the retinas, since treatment improved retinal responses (as measured by electroretinography) to levels similar to control animals.

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New avenue to treat diabetes-related vision problems