UF wound researcher seeks clues to healing corneal scars

A University of Florida medical researcher has received a five-year, $1.6 million grant from the National Institutes of Health to study the basic mechanisms of wound healing in the cornea, the clear tissue covering the eye’s surface.

Gregory Schultz, Ph.D., director of the multidisciplinary UF Institute for Wound Research, is leading studies in rabbits and rats aimed at developing new drugs to prevent excessive corneal scarring.

Bacterial or viral infections, cuts and scratches, chemical exposure or laser-assisted vision correction procedures can cause corneal scars. Laser therapy and corneal transplants are most commonly used to treat such scarring, but these are highly invasive approaches with a risk of infection and no guarantee they’ll work. UF researchers hope to develop an eye drop that could someday be given to people soon after they suffer an eye injury, before severe scarring has the chance to develop.

The cornea is made up of parallel layers of collagen, a fibrous protein. This arrangement allows light to travel unscattered through the cornea to the back of the eye.

When the cornea is injured, scars sometimes form from the jumbled collection of collagen at the site. This build-up is triggered by connective tissue growth factor, a hormone-like protein that scientists now believe is the chief promoter of scarring. The scars impair vision by disrupting the passage of light.

Schultz, also a professor of obstetrics and gynecology at UF’s College of Medicine, and co-investigator Tim Blalock, a UF biochemistry doctoral student, will test two prototype drugs designed to target the growth factor and stop its action. In a previous study, Blalock discovered that levels of connective tissue growth factor increase in injured corneas.

In cells, ribonucleic acid, or RNA, copies genetic code from strands of DNA. RNA then delivers DNA’s genetic instructions. One experimental drug consists of ribozymes—RNA molecules that act like enzymes—that cut through the growth factor’s RNA and prevent the delivery of scarring instructions. Another drug, antisense oligonucleotide, binds to the growth factor’s RNA, also preventing message delivery.

Researchers first will test the drugs on corneal cells in culture, then on the eyes of anesthetized rats and rabbits that have undergone a procedure akin to laser-assisted vision correction.

This research may hold the key to treating of excessive scarring elsewhere in the body, Schultz said.

“We have reason to believe that agents that reduce scarring in the cornea will work in other tissues because connective tissue growth factor stimulates scarring in essentially all tissues in the body,” Schultz said. “This means we may be able develop similar treatments to minimize scarring of the uterus, lungs, kidneys or liver.”