glaucoma
Metabolomics: A New Approach to Understanding Glaucoma
Posted on by Michael F. Chiang, M.D., National Eye Institute
Glaucoma remains one of the most common causes of vision loss and blindness in the U.S. and much of the world, disproportionately affecting older people, African Americans, and Hispanics and Latinos. Early signs of glaucoma can vary, from eye pressure to changes in the appearance of the optic nerve, and the disease can progress for years undetected while causing irreversible vision loss. More research is needed to understand the complex processes that underpin how glaucoma develops and progresses. If detected early enough, doctors can intervene and stop or slow its progression, thus preventing or minimizing vision loss.
While more than 120 genetic factors have been linked to glaucoma, these genes account for less than 10% of glaucoma cases. Scientists are exploring other ways to predict glaucoma, including studying metabolites to see if they hold any clues. These small molecules are produced by metabolism, including the breakdown of nutrients when we digest food or byproducts from the medicine we take. Identifying at-risk individuals based on their metabolic profile might present an opportunity to intercept disease before vision loss.
Researchers already use metabolites as biomarkers or indicators to help diagnose disease or assess disease risk. There’s a standard blood test called a comprehensive metabolic blood panel that doctors use to measure levels of metabolites circulating in your blood—sugars like glucose, minerals such as calcium, and proteins such as creatinine.
Your metabolome is the complete set of metabolites not in just your blood but in your entire body. National Eye Institute-funded researchers led by Louis Pasquale, Icahn School of Medicine at Mount Sinai, New York, in collaboration with Oana A. Zeleznik and Jae Hee Kang of Brigham and Women’s Hospital, Boston, recently explored 369 blood metabolites in relation to glaucoma in a large study.1
The research team examined blood that had been stored frozen from two long-term studies of health professionals: the Nurses’ Health Studies and the Health Professionals’ Follow-Up Study. They compared about 600 participants who had developed glaucoma after study enrollment to a group of similar participants who didn’t. On average, the participants who developed glaucoma did so about 10 years after their initial blood draw in the study.
The researchers found a particularly strong association between glaucoma and two classes of lipids (fats): triglycerides and diglycerides. Patients with elevated triglycerides and diglycerides were more likely to develop glaucoma, and the association was strongest in a subtype of glaucoma that causes early loss of central vision. They confirmed their findings in a cross-sectional analysis of data from the UK Biobank.
High levels of triglycerides have been linked to a variety of health problems, notably heart disease and stroke. The good news is that effective treatments to control triglyceride levels already exist. Statin drugs, for example, lower blood lipid levels. While studies looking at statin use and glaucoma risk have shown mixed results, we may learn that specific subtypes of glaucoma can be effectively controlled with statins. More research is needed to know if existing drugs might prevent glaucoma.
Pasquale’s work adds to a growing body of evidence that links health status to metabolism. Similar associations have been made between various metabolites and kidney cancer,2 pregnancy complications,3 type 2 diabetes,4 and Alzheimer’s disease.5 For researchers interested in exploring associations between metabolites and disease risk, the NIH Common Fund offers scientists a national and international repository for metabolomics data and metadata called the Metabolomics Workbench Metabolite Database, which contained more than 167,000 entries in 2022.
These findings and others offer the potential to prevent more and treat less. We urge anyone in an at-risk group, including people with a family history of glaucoma, to get regular, comprehensive eye exams.
References:
[1] OA Zeleznik, et al. Plasma metabolite profile for primary open-angle glaucoma in three US cohorts and the UK Biobank. Nature Communications DOI:10.1038/s41467-023-38466-x (2023)
[2] OO Bifarin, et al. Urine-Based Metabolomics and Machine Learning Reveals Metabolites Associated with Renal Cell Carcinoma Stage. Cancers (Basel) DOI:10.3390/cancers13246253 (2021)
[3] EW Harville, et al. Untargeted analysis of first trimester serum to reveal biomarkers of pregnancy complications: a case-control discovery phase study. Scientific Reports DOI:10.1038/s41598-021-82804-1 (2021)
[4] Nightingale Health Biobank Collaborative Group, et al. Metabolomic and genomic prediction of common diseases in 477,706 participants in three national biobanks. medRxiv DOI: 10.1101/2023.06.09.23291213 (2023). *note this article is a pre-print and is not peer-reviewed
[5] DK Barupal, et al. Sets of coregulated serum lipids are associated with Alzheimer’s disease pathophysiology. Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring. DOI:10.1016/j.dadm.2019.07.002 (2019)
NIH Support: National Eye Institute, National Cancer Institute
Editor’s note: This blog post was updated on Jan. 18, 2024, to include Oana A. Zeleznik as one of the collaborators.
All of Us: Release of Nearly 100,000 Whole Genome Sequences Sets Stage for New Discoveries
Posted on by Joshua Denny, M.D., M.S., and Lawrence Tabak, D.D.S., Ph.D.
Nearly four years ago, NIH opened national enrollment for the All of Us Research Program. This historic program is building a vital research community within the United States of at least 1 million participant partners from all backgrounds. Its unifying goal is to advance precision medicine, an emerging form of health care tailored specifically to the individual, not the average patient as is now often the case. As part of this historic effort, many participants have offered DNA samples for whole genome sequencing, which provides information about almost all of an individual’s genetic makeup.
Earlier this month, the All of Us Research Program hit an important milestone. We released the first set of nearly 100,000 whole genome sequences from our participant partners. The sequences are stored in the All of Us Researcher Workbench, a powerful, cloud-based analytics platform that makes these data broadly accessible to registered researchers.
The All of Us Research Program and its many participant partners are leading the way toward more equitable representation in medical research. About half of this new genomic information comes from people who self-identify with a racial or ethnic minority group. That’s extremely important because, until now, over 90 percent of participants in large genomic studies were of European descent. This lack of diversity has had huge impacts—deepening health disparities and hindering scientific discovery from fully benefiting everyone.
The Researcher Workbench also contains information from many of the participants’ electronic health records, Fitbit devices, and survey responses. Another neat feature is that the platform links to data from the U.S. Census Bureau’s American Community Survey to provide more details about the communities where participants live.
This unique and comprehensive combination of data will be key in transforming our understanding of health and disease. For example, given the vast amount of data and diversity in the Researcher Workbench, new diseases are undoubtedly waiting to be uncovered and defined. Many new genetic variants are also waiting to be identified that may better predict disease risk and response to treatment.
To speed up the discovery process, these data are being made available, both widely and wisely. To protect participants’ privacy, the program has removed all direct identifiers from the data and upholds strict requirements for researchers seeking access. Already, more than 1,500 scientists across the United States have gained access to the Researcher Workbench through their institutions after completing training and agreeing to the program’s strict rules for responsible use. Some of these researchers are already making discoveries that promote precision medicine, such as finding ways to predict how to best to prevent vision loss in patients with glaucoma.
Beyond making genomic data available for research, All of Us participants have the opportunity to receive their personal DNA results, at no cost to them. So far, the program has offered genetic ancestry and trait results to more than 100,000 participants. Plans are underway to begin sharing health-related DNA results on hereditary disease risk and medication-gene interactions later this year.
This first release of genomic data is a huge milestone for the program and for health research more broadly, but it’s also just the start. The program’s genome centers continue to generate the genomic data and process about 5,000 additional participant DNA samples every week.
The ultimate goal is to gather health data from at least 1 million or more people living in the United States, and there’s plenty of time to join the effort. Whether you would like to contribute your own DNA and health information, engage in research, or support the All of Us Research Program as a partner, it’s easy to get involved. By taking part in this historic program, you can help to build a better and more equitable future for health research and precision medicine.
Note: Joshua Denny, M.D., M.S., is the Chief Executive Officer of NIH’s All of Us Research Program.
Links:
All of Us Research Program (NIH)
Join All of Us (NIH)
Artificial Intelligence Getting Smarter! Innovations from the Vision Field
Posted on by Michael F. Chiang, M.D., National Eye Institute
One of many health risks premature infants face is retinopathy of prematurity (ROP), a leading cause of childhood blindness worldwide. ROP causes abnormal blood vessel growth in the light-sensing eye tissue called the retina. Left untreated, ROP can lead to lead to scarring, retinal detachment, and blindness. It’s the disease that caused singer and songwriter Stevie Wonder to lose his vision.
Now, effective treatments are available—if the disease is diagnosed early and accurately. Advancements in neonatal care have led to the survival of extremely premature infants, who are at highest risk for severe ROP. Despite major advancements in diagnosis and treatment, tragically, about 600 infants in the U.S. still go blind each year from ROP. This disease is difficult to diagnose and manage, even for the most experienced ophthalmologists. And the challenges are much worse in remote corners of the world that have limited access to ophthalmic and neonatal care.
Artificial intelligence (AI) is helping bridge these gaps. Prior to my tenure as National Eye Institute (NEI) director, I helped develop a system called i-ROP Deep Learning (i-ROP DL), which automates the identification of ROP. In essence, we trained a computer to identify subtle abnormalities in retinal blood vessels from thousands of images of premature infant retinas. Strikingly, the i-ROP DL artificial intelligence system outperformed even international ROP experts [1]. This has enormous potential to improve the quality and delivery of eye care to premature infants worldwide.
Of course, the promise of medical artificial intelligence extends far beyond ROP. In 2018, the FDA approved the first autonomous AI-based diagnostic tool in any field of medicine [2]. Called IDx-DR, the system streamlines screening for diabetic retinopathy (DR), and its results require no interpretation by a doctor. DR occurs when blood vessels in the retina grow irregularly, bleed, and potentially cause blindness. About 34 million people in the U.S. have diabetes, and each is at risk for DR.
As with ROP, early diagnosis and intervention is crucial to preventing vision loss to DR. The American Diabetes Association recommends people with diabetes see an eye care provider annually to have their retinas examined for signs of DR. Yet fewer than 50 percent of Americans with diabetes receive these annual eye exams.
The IDx-DR system was conceived by Michael Abramoff, an ophthalmologist and AI expert at the University of Iowa, Iowa City. With NEI funding, Abramoff used deep learning to design a system for use in a primary-care medical setting. A technician with minimal ophthalmology training can use the IDx-DR system to scan a patient’s retinas and get results indicating whether a patient should be sent to an eye specialist for follow-up evaluation or to return for another scan in 12 months.
Many other methodological innovations in AI have occurred in ophthalmology. That’s because imaging is so crucial to disease diagnosis and clinical outcome data are so readily available. As a result, AI-based diagnostic systems are in development for many other eye diseases, including cataract, age-related macular degeneration (AMD), and glaucoma.
Rapid advances in AI are occurring in other medical fields, such as radiology, cardiology, and dermatology. But disease diagnosis is just one of many applications for AI. Neurobiologists are using AI to answer questions about retinal and brain circuitry, disease modeling, microsurgical devices, and drug discovery.
If it sounds too good to be true, it may be. There’s a lot of work that remains to be done. Significant challenges to AI utilization in science and medicine persist. For example, researchers from the University of Washington, Seattle, last year tested seven AI-based screening algorithms that were designed to detect DR. They found under real-world conditions that only one outperformed human screeners [3]. A key problem is these AI algorithms need to be trained with more diverse images and data, including a wider range of races, ethnicities, and populations—as well as different types of cameras.
How do we address these gaps in knowledge? We’ll need larger datasets, a collaborative culture of sharing data and software libraries, broader validation studies, and algorithms to address health inequities and to avoid bias. The NIH Common Fund’s Bridge to Artificial Intelligence (Bridge2AI) project and NIH’s Artificial Intelligence/Machine Learning Consortium to Advance Health Equity and Researcher Diversity (AIM-AHEAD) Program project will be major steps toward addressing those gaps.
So, yes—AI is getting smarter. But harnessing its full power will rely on scientists and clinicians getting smarter, too.
References:
[1] Automated diagnosis of plus disease in retinopathy of prematurity using deep convolutional neural networks. Brown JM, Campbell JP, Beers A, Chang K, Ostmo S, Chan RVP, Dy J, Erdogmus D, Ioannidis S, Kalpathy-Cramer J, Chiang MF; Imaging and Informatics in Retinopathy of Prematurity (i-ROP) Research Consortium. JAMA Ophthalmol. 2018 Jul 1;136(7):803-810.
[2] FDA permits marketing of artificial intelligence-based device to detect certain diabetes-related eye problems. Food and Drug Administration. April 11, 2018.
[3] Multicenter, head-to-head, real-world validation study of seven automated artificial intelligence diabetic retinopathy screening systems. Lee AY, Yanagihara RT, Lee CS, Blazes M, Jung HC, Chee YE, Gencarella MD, Gee H, Maa AY, Cockerham GC, Lynch M, Boyko EJ. Diabetes Care. 2021 May;44(5):1168-1175.
Links:
Retinopathy of Prematurity (National Eye Institute/NIH)
Diabetic Eye Disease (NEI)
Michael Abramoff (University of Iowa, Iowa City)
Bridge to Artificial Intelligence (Common Fund/NIH)
[Note: Acting NIH Director Lawrence Tabak has asked the heads of NIH’s institutes and centers to contribute occasional guest posts to the blog as a way to highlight some of the cool science that they support and conduct. This is the second in the series of NIH institute and center guest posts that will run until a new permanent NIH director is in place.]
Preventing Glaucoma Vision Loss with ‘Big Data’
Posted on by Dr. Francis Collins
Each morning, more than 2 million Americans start their rise-and-shine routine by remembering to take their eye drops. The drops treat their open-angle glaucoma, the most-common form of the disease, caused by obstructed drainage of fluid where the eye’s cornea and iris meet. The slow drainage increases fluid pressure at the front of the eye. Meanwhile, at the back of the eye, fluid pushes on the optic nerve, causing its bundled fibers to fray and leading to gradual loss of side vision.
For many, the eye drops help to lower intraocular pressure and prevent vision loss. But for others, the drops aren’t sufficient and their intraocular pressure remains high. Such people will need next-level care, possibly including eye surgery, to reopen the clogged drainage ducts and slow this disease that disproportionately affects older adults and African Americans over age 40.
Credit: University of California San Diego
Sally Baxter, a physician-scientist with expertise in ophthalmology at the University of California, San Diego (UCSD), wants to learn how to predict who is at greatest risk for serious vision loss from open-angle and other forms of glaucoma. That way, they can receive more aggressive early care to protect their vision from this second-leading cause of blindness in the U.S..
To pursue this challenging research goal, Baxter has received a 2020 NIH Director’s Early Independence Award. Her research will build on the clinical observation that people with glaucoma frequently battle other chronic health problems, such as high blood pressure, diabetes, and heart disease. To learn more about how these and other chronic health conditions might influence glaucoma outcomes, Baxter has begun mining a rich source of data: electronic health records (EHRs).
In an earlier study of patients at UCSD, Baxter showed that EHR data helped to predict which people would need glaucoma surgery within the next six months [1]. The finding suggested that the EHR, especially information on a patient’s blood pressure and medications, could predict the risk for worsening glaucoma.
In her NIH-supported work, she’s already extended this earlier “Big Data” finding by analyzing data from more than 1,200 people with glaucoma who participate in NIH’s All of Us Research Program [2]. With consent from the participants, Baxter used their EHRs to train a computer to find telltale patterns within the data and then predict with 80 to 99 percent accuracy who would later require eye surgery.
The findings confirm that machine learning approaches and EHR data can indeed help in managing people with glaucoma. That’s true even when the EHR data don’t contain any information specific to a person’s eye health.
In fact, the work of Baxter and other groups have pointed to an especially important role for blood pressure in shaping glaucoma outcomes. Hoping to explore this lead further with the support of her Early Independence Award, Baxter also will enroll patients in a study to test whether blood-pressure monitoring smart watches can add important predictive information on glaucoma progression. By combining round-the-clock blood pressure data with EHR data, she hopes to predict glaucoma progression with even greater precision. She’s also exploring innovative ways to track whether people with glaucoma use their eye drops as prescribed, which is another important predictor of the risk of irreversible vision loss [3].
Glaucoma research continues to undergo great progress. This progress ranges from basic research to the development of new treatments and high-resolution imaging technologies to improve diagnostics. But Baxter’s quest to develop practical clinical tools hold great promise, too, and hopefully will help one day to protect the vision of millions of people with glaucoma around the world.
References:
[1] Machine learning-based predictive modeling of surgical intervention in glaucoma using systemic data from electronic health records. Baxter SL, Marks C, Kuo TT, Ohno-Machado L, Weinreb RN. Am J Ophthalmol. 2019 Dec; 208:30-40.
[2] Predictive analytics for glaucoma using data from the All of Us Research Program. Baxter SL, Saseendrakumar BR, Paul P, Kim J, Bonomi L, Kuo TT, Loperena R, Ratsimbazafy F, Boerwinkle E, Cicek M, Clark CR, Cohn E, Gebo K, Mayo K, Mockrin S, Schully SD, Ramirez A, Ohno-Machado L; All of Us Research Program Investigators. Am J Ophthalmol. 2021 Jul;227:74-86.
[3] Smart electronic eyedrop bottle for unobtrusive monitoring of glaucoma medication adherence. Aguilar-Rivera M, Erudaitius DT, Wu VM, Tantiongloc JC, Kang DY, Coleman TP, Baxter SL, Weinreb RN. Sensors (Basel). 2020 Apr 30;20(9):2570.
Links:
Glaucoma (National Eye Institute/NIH)
All of Us Research Program (NIH)
Video: Sally Baxter (All of Us Research Program)
Sally Baxter (University of California San Diego)
Baxter Project Information (NIH RePORTER)
NIH Director’s Early Independence Award (Common Fund)
NIH Support: Common Fund
Snapshots of Life: Lighting up the Promise of Retinal Gene Therapy
Posted on by Dr. Francis Collins
Caption: Large-scale mosaic confocal micrograph showing expression of a marker gene (yellow) transferred by gene therapy techniques into the ganglion cells (blue) of a mouse retina.
Credit: Keunyoung Kim, Wonkyu Ju, and Mark Ellisman, National Center for Microscopy and Imaging Research, University of California, San Diego
The retina, like this one from a mouse that is flattened out and captured in a beautiful image, is a thin tissue that lines the back of the eye. Although only about the size of a postage stamp, the retina contains more than 100 distinct cell types that are organized into multiple information-processing layers. These layers work together to absorb light and translate it into electrical signals that stream via the optic nerve to the brain.
In people with inherited disorders in which the retina degenerates, an altered gene somewhere within this nexus of cells progressively robs them of their sight. This has led to a number of human clinical trials—with some encouraging progress being reported for at least one condition, Leber congenital amaurosis—that are transferring a normal version of the affected gene into retinal cells in hopes of restoring lost vision.
To better understand and improve this potential therapeutic strategy, researchers are gauging the efficiency of gene transfer into the retina via an imaging technique called large-scale mosaic confocal microscopy, which computationally assembles many small, high-resolution images in a way similar to Google Earth. In the example you see above, NIH-supported researchers Wonkyu Ju, Mark Ellisman, and their colleagues at the University of California, San Diego, engineered adeno-associated virus serotype 2 (AAV2) to deliver a dummy gene tagged with a fluorescent marker (yellow) into the ganglion cells (blue) of a mouse retina. Two months after AAV-mediated gene delivery, yellow had overlaid most of the blue, indicating the dummy gene had been selectively transferred into retinal ganglion cells at a high rate of efficiency [1].
Snapshots of Life: Seeing, from Eye to Brain
Posted on by Dr. Francis Collins
| Credit: Xueting Luo and Kevin Park, University of Miami |
Fasten your seat belts! We’re going to fly through the brain of a mouse. Our tour guide is Kevin Park, an NIH-funded neuroscientist at the University of Miami, who has developed a unique method to visualize neurons in an intact brain. He’s going to give us a rare close-up of the retinal ganglion cells that carry information from the eye to the brain, where the light signals are decoded and translated.
To make this movie, Park has injected a fluorescent dye into the mouse eye; it is taken up by the retinal cells and traces out the nerve pathways from the optic nerve into the brain.
Guarding Against Glaucoma: What Can We Do?
Posted on by Dr. Francis Collins
This graph provides a frightening look at a problem that could threaten the vision of more than 6 million Americans by 2050: glaucoma. Glaucoma is a group of diseases that damage the eye’s optic nerve — a bundle of 1 million-plus nerve fibers connecting the light-sensitive retina to the brain — and that can lead to vision loss and blindness.
NIH research is trying to change this picture by developing better strategies for treatment and prevention. But you can also help. How? By getting your eyes checked regularly.
With early detection and treatment, serious vision loss can often be prevented. Anyone can develop glaucoma, but some folks are at higher risk:
- African Americans over age 40
- Everyone over age 60, especially Mexican Americans
- People with a family history of glaucoma
Glaucoma often has no symptoms until a lot of damage has already been done. So the best way to prevent a bad outcome from glaucoma is by undergoing a simple eye exam that can be done by an ophthalmologist or an optometrist — at least once every 2 years for people in high-risk groups.
Source: National Eye Institute, NIH
