Study helps lay foundation for a better understanding of diabetic retinopathy

A new study seeks to boost understanding of how diabetic retinopathy occurs, with the hope that new knowledge can lead to the development of therapeutic interventions that can slow the eye disease's progression and preserve patients' vision.

The study, "Senescence-associated secretory phenotype contributes to pathological angiogenesis in retinopathy," appears in the Oct. 26 issue of Science Translational Medicine. The study investigated why retinal neurons live on in ischemic retinopathies, even though their metabolic supply is diminished. It also considered the role of cellular senescence or cells' decline as they age. Researchers were from the Université de Montréal, Montreal, Quebec; McGill University, Montreal, Quebec; and Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California.

Diabetic retinopathy is a complication of diabetes, affecting the small blood vessels in the eyes. An estimated 1 in 3 people with diabetes have diabetic retinopathy.

"The current study suggests that in retinopathies, cellular senescence exerts dichotomous roles within the same disease in that it first likely protects neurons from cell death yet concurrently prevents them from triggering programs of reparative angiogenesis," the authors write. "In addition, the paracrine senescence observed, and associated production of vasomodulatory factors in retinopathies, contributes to repelling neovessels to the physiologically avascular vitreous and may promote premature aging-related complication in retinal vasculature.

"Hence, preventing cellular senescence during a phase of pathological retinal neovascularization with intravitreal administration of modulators of senescence could represent a simple therapeutic solution for these primary causes of blindness," they add.

Millions affected

According to the Centers for Disease Control and Prevention, diabetes accounts for most of the new cases of adult blindness in this country. About 29 million people are affected. Diabetic retinopathy is a progressive eye disease that damages the blood vessels in the retina due to the leakage of blood and other fluids from the retina. The leakage aggravates the retinal tissue, causing it to swell up and impact vision. Untreated, it can cause blindness.

Symptoms of diabetic retinopathy include:

• Seeing spots or floaters
• Blurring vision
• Having a dark or empty spot in the center of your vision
• Experiencing difficulty seeing well at night

Laying a foundation

Mile Brujic, O.D., practices in Bowling Green, Ohio, and specializes in ocular disease management of the anterior segment of the eye and has lectured nationally and internationally. Dr. Brujic calls the study significant, as it furthers understanding of diabetic retinopathy.

"This further supports what we see clinically in the advancing diabetic eye where we detect progression to proliferative diabetic retinopathy," says Dr. Brujic, who serves on the AOA's Continuing Education Subcommittee. "This lays the foundation for a better biochemical understanding of the pathway. Ultimately, this will hopefully be the stepping stone to more targeted therapeutics in treating these patients."

He adds, "As optometrists, we should follow the study and become increasingly familiar with biochemical pathways so they are better understood. The more knowledge we have in these areas, the better we are able to ultimately care for our diabetic patients."

Dr. Brujic says further study is needed because Canadian researchers used mouse models.

"This is fascinating information and the mouse model is a well-established one," he says. "But this has to be proven in patient trials to ultimately develop appropriate therapeutics that may be utilized clinically."

"Diabetes is a complex condition," he says. "There are things that can now be utilized to help improve patients' visual outcomes. The Diabetes Visual Function Supplementation Study, for example, showed that in a placebo-controlled study, improvement in a number of different visual function measurements occurred by taking a multicomponent formula containing xanthophyll pigments, antioxidants and selected botanical extracts.

"It is truly telling that appropriate recommendations of antioxidants and other micronutrients can provide diabetic patients better functional visual outcomes," he adds.

The AOA follows all research closely, including potential diabetic retinopathy treatments. Although this study offers interesting treatment possibilities for patients, more research is needed regarding its impact on visual health.