For many people with diabetes, vision loss is a major concern. A condition called diabetic retinopathy, which can affect people with type 1 and type 2 diabetes, results when blood vessels in the eye’s retina are damaged. It can lead to gradual vision loss and, eventually, blindness.
The retina, considered part of the central nervous system, is a layer of tissue at the back of the eye that transforms light into electrical impulses that are sent to the brain, which interprets the signals as the images we see.
Normally, light causes the retina’s blood vessels to dilate, bringing extra oxygen and glucose to active retinal cells to keep them healthy and functioning properly, explains University of Minnesota neuroscientist Eric Newman, Ph.D. But with disease, light doesn’t cause dilation or increase blood flow, and the retina doesn’t get the nutrients it needs.
Newman, a Distinguished McKnight University Professor, has studied how neurons communicate with blood vessels to cause dilation and how that process goes awry in disease. His lab has used a rat model to show that the retina’s light-evoked blood vessel dilation is lost after seven months with diabetes—evidence of diabetic retinopathy in progress.
Now Newman wants to discover whether it’s possible to reverse this loss of blood vessel response using chemical inhibitors.
Newman’s research has been funded by the National Institutes of Health for nearly three decades. And in March, he received word that he’ll be receiving another four-year, $1.51 million grant to support the next steps in his diabetic retinopathy work. Additional grants from the American Recovery and Reinvestment Act of 2009 and Minnesota Medical Foundation are supporting these studies.
So far Newman’s team, which includes graduate students Anusha Mishra and Anja Srienc, has analyzed the retinas of diabetic rats by removing them and examining them under a microscope. He now plans to test whether chemical inhibitors can reverse the loss of blood vessel response in live rats.
The research testing whether chemical inhibitors can slow vision loss caused by diabetic retinopathy is still in an early stage, Newman emphasizes, and is likely years away from any treatment for humans. Still, its potential is exciting.
“Potentially, if you can restore the vascular response, you might be able to slow down or limit the damage [caused by the disease],” Newman says.