UA scientist led research on macular degeneration

A UA scientist led a study on age-related macular degeneration that eventually could help delay or prevent the eye disease, researchers say.

The study found that patients who take levodopa, or l-dopa, a common treatment for Parkinson’s disease, appear far less likely to develop macular degeneration, said Brian S. McKay, a co-principal investigator.

McKay is associate professor of ophthalmology and vision science and cellular and molecular medicine at the University of Arizona College of Medicine.

“It is likely that this will lead to a way to prevent age-related macular degeneration, and it may also lead to treatment for macular degeneration in the future,” said McKay. He said the potential treatment could help with other eye diseases characterized by retinal degeneration, which can also cause blindness.

“Thirty percent of people over age 70 in the United States have age-related macular degeneration,” said McKay in a telephone interview. “The majority of those are white,” he said, explaining that studies showed that race and pigmentation were the key factors involved in the risk of developing age-related macular degeneration. The disease is much less common among Hispanics and blacks, he said.

The eye disease gradually destroys the ability to read, drive, write and see close-up in 30 percent of older Americans, according to the UA.

The research was published online in the American Journal of Medicine — www.amjmed.com

A team of retina specialists are developing a clinical trial of 500 participants to validate the research findings. McKay hopes the trial will begin in early 2016 and be completed in 2018.

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If the trial proves the findings, then the “FDA will be motivated to re-purpose the drug” for the prevention and treatment of age-related macular degeneration, said McKay.

McKay said he began his research — studying pigmentation pathways and how that altered vision — at Duke University in 2000 when he was on the faculty. He continued his research when he started working for the UA in 2002. He worked with co-principal investigator Murray Brilliant, who then was a medical genetics researcher at the UA. Brilliant is now director of the Marshfield Clinic Research Foundation Center for Human Genetics in Wisconsin.

McKay discovered that the support tissue for the retina expressed a receptor for l-dopa. He said he questioned whether if “a lot of the older people who take l-dopa every day get age-related macular degeneration.” This led to continued research, and he and Brilliant analyzed the health records of 37,000 patients in a database at the Marshfield Clinic to see who suffered from macular degeneration and who took l-dopa, or both.

Retinal surgeons were contacted to expand the study, which led to 14 investigators to further the research, said McKay. In addition to the UA and the Marshfield Clinic, investigators include researchers from the University of Miami, Stanford University, University of Southern California, the Medical College of Wisconsin and the Essentia Institute of Rural Health in Duluth, Minnesota.

After analyzing the records of 37,000 patients, the next phase of the research, said McKay, was analyzing 87 million patients’ medical records from an insurance-industry database, and the same connection between l-dopa and macular degeneration held. The researchers are now developing the clinical trial.

“I have been working on this for a long time. It is good to see it finishing up,” said McKay, adding that he was thankful to the local chapters of the Lions Clubs International for transporting donor tissue from Phoenix to his laboratory for the studies.

He said he also was thankful to the families who donated their loved ones’ organs that made the studies possible.

McKay “has been tenacious in his investigation of blinding eye disease, and with the help of many others — patients, doctors and public health workers — we now have a new direction for possible interruption of the pathway from sight to blindness,” said Dr. Joseph Miller, head of the Department of Ophthalmology and Vision Science at the UA College of Medicine.