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Posted: April 03, 2006

Researchers Begin Work on Newly-Funded Glaucoma Study

yorio2.jpg Thomas Yorio, PhD, dean of the Graduate School of Biomedical Sciences and Vice President for Research at UNT Health Science Center, received almost $2 million from the National Eye Institute to study the use of topical drug treatments for patients with glaucoma.

The project is in conjunction with Xinu Zhang, PhD, research scientist at the health science center; Lee Alward, MD, from the University of Iowa; and Abe Clark, PhD, of Alcon Research, Ltd., are serving as a co-investigators on the project.

The five-year grant titled “Glucocorticoids, Ocular Hypertension and Glaucoma” pairs lab research and patient care to discover why patients with glaucoma have increased intraocular pressure when treated with topical glucocorticoids. This increase in eye pressure can exacerbate glaucoma or create ocular damage if patients are treated for long periods of time with glucocorticoids.

“This would allow us to determine if what we suspect is true, that the increased responsiveness to the drugs may be due to differences in the amount of receptors that individuals have for the glucocorticoids,” Dr. Yorio said.

Glaucoma is a group of diseases that leads to blindness by damaging the optic nerve. The optic nerve is responsible for carrying images from the eye to the brain, which is why damage to it leads to vision loss. Glaucoma is one of the leading cause of blindness, and currently, there is no cure for it, although it can be treated and its progression slowed by early detection. Experts from the Glaucoma Research Foundation estimate that half of the people affected by glaucoma may not know that they have the disease.

What Dr. Yorio and the researchers in this project have hypothesized is that glaucoma patients are missing an interference receptor known as glucocorticoid receptor beta. Because the receptor is missing in the nucleus the response to administered glucocorticoids is enhanced in these patients. This could allow for a screening method to determine what patients would be likely to develop glaucoma.

“If this were the case, we would be able to intervene with treatment before appreciable vision loss is detected,” Dr. Yorio said.

Dr. Yorio’s lab at the health science center will look at the molecular biology and cellular mechanisms associated with glucocorticoid administration, trying to determine if differences exist in the receptors of glaucoma patients. Dr. Clark will work with Dr. Yorio to examine tissues and cells for mechanisms that could account for the differences in glucocorticoid responsiveness between normal patients and patients with glaucoma. Dr. Alward will examine patients with glaucoma and without glaucoma to determine genetic differences in the pathways that have been identified by Dr. Yorio’s lab.

This project grew out of the research of Dr. Zhang, when she was a graduate student in Dr. Yorio’s laboratory. Dr. Zhang’s initial studies were recently published in the journal Investigative Ophthalmology and Visual Science. A figure from one of her publications appears on the cover of the February issue of the journal.

“Dr. Zhang’s research has led to a most interesting observation that could result in making a profound discovery on the relationship between glucocorticoid receptors and glaucoma,” Dr. Yorio said.

“I’ve been studying eye diseases for more than 30 years, with specific emphasis on glaucoma. This study is just part of an overall program in our laboratory to understand the fundamental cellular mechanisms that lead to the development of glaucoma and to identify potential new treatments. Our laboratory has several patents and applications pending on new discoveries for the treatment of this ocular neurodegenerative disease.”


Contact: Kay Colley 817-735-2553, cell 817-980-5090, e-mail kacolley@hsc.unt.edu.

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