Researchers from the WashU Medicine John F. Hardesty, MD Department of Ophthalmology & Visual Sciences Apte Lab have identified a potential new way to detect primary open-angle glaucoma (POAG) using a molecule found in tears. The study, led by researchers in the Apte Lab in collaboration with glaucoma specialists, found that levels of growth differentiation factor 15 (GDF15) are elevated in the tears of patients with POAG and correlate with GDF15 levels found inside the eye. The findings suggest that GDF15 could eventually serve as a convenient, noninvasive molecular biomarker to help detect glaucoma.
Glaucoma is a leading cause of irreversible vision loss, and early detection is critical to preserving vision. However, glaucoma can develop gradually without noticeable symptoms, making timely diagnosis and monitoring especially important.
The Apte Lab previously found that GDF15, an inflammatory cytokine associated with optic nerve stress, is elevated in mouse models of glaucoma and in the aqueous humor—the fluid inside the front of the eye—of patients with POAG. In this study, the research team investigated whether GDF15 could also be detected in tears and whether tear levels reflected GDF15 levels within the eye.
The study included patients with moderate to severe POAG undergoing glaucoma or cataract surgery and patients without glaucoma undergoing cataract surgery. Researchers collected tear samples using Schirmer strips and aqueous humor samples during surgery. GDF15 concentrations were then measured in both samples.
The researchers found that GDF15 was detectable in nearly all tear samples and was significantly higher in patients with POAG than in individuals without glaucoma. They also found that tear GDF15 levels correlated with aqueous humor GDF15 levels after normalization to total protein, supporting the potential for tear GDF15 to reflect molecular changes occurring within the eye.
The study was led by Cory N. Sharp, Kenta Kato, Andrea Santeford, MS, and Mitsukuni Yoshida, MD, PhD of the Apte Lab, in collaboration with glaucoma faculty Erin Sieck, MD, and Arsham Sheybani, MD, and senior author Rajendra S. Apte, MD, PhD.
“It is important to detect glaucoma early and determine severity and progression in a timely manner so that treating physicians can make appropriate decisions with their patients to prevent long-term vision loss,” said Apte. “Molecular biomarkers that are sensitive and specific will help physicians make such decisions in a timely manner, and this research opens the door for such a possibility.”
The findings highlight the potential of tears as a source of molecular information about eye health. Unlike aqueous humor, which requires an intraocular procedure to collect, tears can be obtained safely and noninvasively, creating the possibility of developing a more convenient approach to molecular testing for glaucoma.
While the findings are promising, larger studies are needed to validate tear GDF15 as a glaucoma biomarker and determine how it could be used to detect disease, assess severity, or monitor progression. The research represents an important step toward developing molecular tools that could complement existing methods of glaucoma diagnosis and management.
The study, “Tear GDF15 Levels Are Elevated in Primary Open-Angle Glaucoma Patients and Correlate With Aqueous Humor Levels,” was published in Current Eye Research.
About WashU Medicine
WashU Medicine is a global leader in academic medicine, including biomedical research, patient care and educational programs with 2,900 faculty. Its National Institutes of Health (NIH) research funding portfolio is the second largest among U.S. medical schools and has grown 56% in the last seven years. Together with institutional investment, WashU Medicine commits well over $1 billion annually to basic and clinical research innovation and training. Its faculty practice is consistently within the top five in the country, with more than 1,900 faculty physicians practicing at 130 locations and who are also the medical staffs of Barnes-Jewish and St. Louis Children’s hospitals of BJC HealthCare. WashU Medicine has a storied history in MD/PhD training, recently dedicated $100 million to scholarships and curriculum renewal for its medical students, and is home to top-notch training programs in every medical subspecialty as well as physical therapy, occupational therapy, and audiology and communications sciences.