By combining data on optometry patients’ eyes with advanced computational methods, IU researchers have created a virtual tissue model of diabetes in the eye, according to a press release.
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, according to a press release.
The research was conducted by scientists at the IU School of Optometry and the Biocomplexity Institute in the IU School of Informatics and Computing.
“With the current epidemic of diabetes in adults, the number of people with vision damage from diabetes will continue to rise,” Dr. Thomas Gast said in a press release. Gast is 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 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, according to a press release.
The spread of damage from region to region depends on the detailed pattern of blood vessels in each patient and the amount of blood they carry, both of which vary greatly from person to person. Based on a patient’s specific vascular structure, the IU scientists’ new model calculates how much a blockage in one blood vessel will increase the probability of blockage in each neighboring vessel. As a result, their program predicts the specific rate and pattern of this cascading vascular damage in the individual.
Current treatment to stop this spread, called laser photocoagulation, places an approximately 1-millimeter-square grid of burns uniformly across the back of the retina outside the area of good vision.
These burns destroy areas of retina that consume oxygen, allowing extra oxygen to move into the retina from deeper vessels behind the retina. They also create blind spots, and many patients require multiple treatments that can impair their side and night vision.
“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 in a press release.
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. This greatly reduces 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 on animals and, ultimately, will look to others to partner on clinical trials that implement the new treatment in humans.
“Our goal is not only to deliver answers about one disease or biological process but to provide a tool that allows researchers to answer many types of questions,” said James A. Glazier in a press release. Glazier is the director of the IU Biocomplexity Institute, who is also an author on the paper, as well as on another recent paper that computationally described the mechanisms underlying polycystic kidney disease. “No effort anywhere else attempts to provide a general solution for deploying virtual tissues across a whole range of significant biomedical questions.”
This study was supported in part by the National Institutes of Health, the Falk Foundation and the IU Collaborative Research Grant Program.
Leo Smith
