May 28, 2015
Can targeting of aging biochemical pathways reduce risk of glaucoma?
U-M study finds that persons with diabetes who take metformin hydrochloride show reduced odds of developing open-angle glaucoma
Dr. Julia Richards
ANN ARBOR—The research world has long known that living on a diet consisting of substantially reduced calories (caloric restriction) or consuming drugs that affect the biochemical pathways that are affected by very low calorie diets (caloric restriction mimetic drugs) can help reduce the risk of some kinds of diseases that are common in older age. One of these caloric restriction mimetic drugs is metformin hydrochloride, a medication that is frequently used to treat patients with type 2 diabetes mellitus.
Researchers at the University of Michigan Kellogg Eye Center wanted to know whether use of this geroprotective drug metformin might be associated with the reduced risk of open-angle glaucoma, a condition that often starts in late middle-age or late-age and causes progressive loss of peripheral vision and, over time, can lead to permanent blindness.
According to their study, published in the Journal of the American Medical Association (JAMA) Ophthalmology, these U-M researchers found that people with diabetes who consumed large quantities of metformin had a reduction in the risk of developing open-angle glaucoma compared to others with diabetes who did not take this medication. Use of other types of medications to treat diabetes did not confer a similar risk reduction.
Julia E. Richards, Ph.D., the Harold F. Falls Collegiate Professor of Ophthalmology and Visual Sciences at Kellogg and Professor of Epidemiology at U-M, and her co-authors performed the analysis using data from a large U.S. health insurance database that captured the medical care of over 150,000 patients with diabetes from 2001 to 2010. The researchers were able to capture information about who filled prescriptions for an array of different medications.
The study revealed that patients prescribed the highest amount of metformin (greater than 1,110 grams in two years) had a 25 percent reduced risk of developing glaucoma compared with those who took no metformin. Diabetics taking a standard dose of two grams of metformin per day for two years had nearly a 21 percent reduction in risk of glaucoma compared to others who were not prescribed this medication.
Because this class of drug is known to target genes in pathways involved in aging and longevity, this study raises intriguing questions about whether the association of this drug with reduced glaucoma risk involves the action of this drug on aging pathways. “If a geroprotective drug is associated with reduced risk of glaucoma, we want to know how it effects risk of other ocular diseases of older age such as macular degeneration, diabetic retinopathy, or cataract,” suggests Dr. Richards.
For now, there are limits to the conclusions that can be drawn from this study, since this was not a randomized clinical trial and it was carried out on a very specific population of persons with diabetes. "Should these findings be confirmed in other populations and in other kinds of studies, they may lead to novel treatments for this sight-threatening disease and offer new opportunities to reduce other risks of aging,” says Dr. Richards.
Citation: Hsien-Chang Lin, PhD1; Joshua D. Stein, MD, MS2,3; Bin Nan, PhD4; David Childers, MA2,5; Paula Anne Newman-Casey, MD, MS2,3; Debra A. Thompson, PhD2,6; Julia E. Richards, PhD7
Funding/Support: This work was supported by exploratory/developmental grant R21-EY021000 (Dr. Richards) and K23 Mentored Clinician Scientist Awards 1K23EY019511 (Dr. Stein) and K12EY022299 (Dr. Newman-Casey) from the National Eye Institute, a fellowship from the Heed Foundation (Dr. Newman-Casey), and a physician-scientist award (Dr. Stein) and unrestricted grant from Research to Prevent Blindness.
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