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 within Emory Eye Center have discovered. Researchers Machelle Pardue. Moe Aung and Michael Iuvone tested vision in diabetic mice after receiving L-DOPA and showed a slowing of early visual loss.
Diabetic retinopathy affects more than a quarter of adults with diabetes and threatens the vision of more than 600,000 people in the United States. Doctors previously thought most of the impairment of vision in diabetic retinopathy came from damage to the blood vessels induced by high blood sugar but also knew that dopamine, a vital neurotransmitter in the brain, was important in the retina.
"There was some evidence already that dopamine levels were reduced in diabetic retinopathy, but what's new is that we can restore dopamine levels and improve visual function in an animal model of diabetes."
Vision was assessed by putting mice on a platform and measuring whether they moved their heads in response to a rotating pattern of vertical lines projected on a cylinder around the mouse (see graphic). The width and contrast of the lines can be modulated to test the mouse's vision.
"This is important because it shows that treatments targeting dopamine could be beneficial to patients with established diabetes."