IU research points toward new blindness prevention methods in diabetic eye disease
Aug. 10, 2016
By combining data on optometry patients' eyes with advanced computational methods, Indiana University researchers have created a virtual tissue model of diabetes in the eye.
The results, reported in the journal PLOS Computational Biology, show precisely how a small protein that can both damage or grow blood vessels in the eye causes vision loss and blindness in people with diabetes. The study could also lead to better treatment for diabetic retinopathy, which currently requires multiple invasive procedures that aren’t always effective in the long term.
A common cause of vision loss in people with diabetes, diabetic retinopathy is responsible for 1 percent of all blindness worldwide and is a leading cause of blindness in American adults.
"With the current epidemic of diabetes in adults, the number of people with vision damage from diabetes will continue to rise," said Dr. Thomas Gast, an ophthalmologist and senior scientist at the IU School of Optometry, who was a lead author on the study. "This paper establishes a step-by-step pathway from a diabetic’s elevated blood sugars to the vascular complications in the eye. Therapeutically, understanding a disease can lead to improved treatments."
A major way diabetic retinopathy threatens vision is diabetic edema. In this condition, the smallest vessels supplying the retina with oxygen become leaky, causing fluid to swell the central retinal area and impairing the type of vision required for precise activities such as reading.
The virtual retina model in the IU study provides the first strong evidence for why this pattern of disease progression is so variable, and it predicts where damage will occur next. It shows that the blockage of one vessel causes a local loss of oxygen in the retina, which triggers release of VEGF that spreads over a larger region which, in turn, increases the probability of blockage in the surrounding vessels, creating a "domino effect."
"Our analysis suggests treatment of the retina with a large number of very small laser burns could prevent this 'domino-like' progressive loss of small retinal blood vessels and prevent elevation of VEGF and the major complications of diabetic retinopathy," Gast said.
This individualized therapy would strategically place "firebreaks" of much smaller burns around areas from which the model predicts vascular damage will spread in that patient, greatly reducing the total amount of damage and reducing the probability that damage will spread between the burns and propagate despite treatment. The IU team is now planning studies in animals and, ultimately, will look to others to partner on clinical trials that implement the new treatment in humans.
Other authors on the diabetic retinopathy study are Stephen A. Burns, professor in the IU School of Optometry, and John Gens, assistant scientist, and Xiao Fu, graduate student, of the IU Biocomplexity Institute. Gast and Burns imaged the patients’ retinal capillaries. Fu and Glazier created the virtual diabetic retina model. Gast and Gens synthesized past animal and clinical studies on diabetic retinopathy.