Routine eye scans may give clues to cognitive decline in diabetes

January 05, 2021

BOSTON - (January 4, 2021) - As they age, people with diabetes are more likely to develop Alzheimer's disease and other cognitive disorders than are people without diabetes. Scientists at Joslin Diabetes Center now have shown that routine eye imaging can identify changes in the retina that may be associated with cognitive disorders in older people with type 1 diabetes.

These results may open up a relatively easy method for early detection of cognitive decline in this population, providing better ways to understand, diagnose and ultimately treat the decline, said George L. King, MD, Joslin's Chief Scientific Officer and senior author on a paper about the study in the Journal of Clinical Endocrinology & Metabolism.

Previous research had demonstrated an association between proliferative diabetic retinopathy (PDR, a complication of diabetes that can severely damage eyesight) and cognitive impairment in people with type 1 diabetes. "Since we knew that there were cellular changes in the retina that might reflect changes in the brain, we were interested to see whether imaging techniques that visualize those changes in the retina might be reflective of changes in cognitive functions," said Ward Fickweiler, MD, a Joslin postdoctoral fellow and first author on the paper.

The scientists drew on eye scans routinely gathered from patients as part of normal vision care at Joslin's Beetham Eye Institute. One set of scans was based on optical coherence tomography (OCT, a technique employing light to provide cross-sections of the retina). A second set of scans employed OCT angiography (OCTA, an extension of OCT technology that examines blood vessels in the retina). Both types of scans are non-invasive and widely available in eye clinics in the United States, and can be performed within minutes.

The study enlisted 129 participants in the Joslin Medalist Study, which examines outcomes among people who have had type 1 diabetes for 50 years or longer. These volunteers took a series of cognitive tests that included tasks probing memory function as well as psychomotor speed (assessing the time it took to arrange objects by hand).

Strikingly, the researchers found very strong associations between performance on memory tasks and structural changes in deep blood vessel networks in the retina. "Memory is the main cognitive task that is affected in Alzheimer's disease and cognitive decline, so that was exciting," Fickweiler said.

The Joslin team also discovered strong associations between PDR and psychomotor speed. This finding reinforced earlier outcomes that had been identified among a smaller group of Joslin Medalists, and provided details about related changes in retinal structure. Additionally, the researchers saw that PDR was associated with memory performance among the larger group of Medalists.

While these results need to be confirmed in larger clinical investigations, the routine eye exams do seem to detect the cognitive changes happening in people with diabetes, said Fickweiler.

Currently, other ways to detect conditions such as Alzheimer's disease such as MRI scans are difficult and expensive. People typically are tested only when they're showing symptoms of cognitive decline and treatments at that stage generally don't offer much help.

"If you can detect the condition at an earlier stage, when they're still asymptomatic, that may benefit patients," Fickweiler said. Earlier detection also could aid the quest to develop better therapies for neurocognitive diseases.

The Joslin team plans to launch a larger prospective study to confirm the potential of eye imaging to pick up signs of cognitive decline over time. This research will include people with type 1 diabetes who are younger and haven't had the disease for as long as the Medalists. The scientists also will analyze MRI brain images and postmortem brain samples donated by Medalists.

Additionally, the investigators will look for common mechanisms that may inflict damage on brain and retina tissues, which share much of their early embryonic development pathways. Likely suspects in people with diabetes include impaired blood vessels and high or low levels of blood glucose. The autoimmunity that drives type 1 diabetes also might inflict other forms of harm, King said.

Notably, Joslin Medalists often display relatively low levels of the complications that can afflict those with long-term type 1 diabetes. For instance, almost half of Medalists don't develop advanced eye disease, and only one of the 129 Medalists in the eye-scan study may have Alzheimer's disease. "It is possible that in the Medalists, a shared mechanism alters the progression of the early stages of retinal and brain neurodegeneration, and provides protection against both PDR and Alzheimer's disease," Fickweiler speculated.

In addition to follow-up work in type 1 diabetes, King and his team plan to perform a similar study for people with type 2 diabetes. PDR also is associated with cognitive decline in this much larger group of patients, who also get OCT and OCTA eye scans as part of their regular vision care.
-end-
The paper's co-authors include Joslin's Emily Wolfson, Samantha Paniagua, Atif Adam, Vanessa Bahnam, Konstantina Sampani, I-Hsien Wu, Gail Musen, Lloyd Aiello, Hetal Shah and Jennifer Sun. Marc Yu of Harvard Medical School also contributed.

Funding came from the Dianne Nunnally Hoppes Fund; the Beatson Pledge Fund; the National Institute of Diabetes and Digestive and Kidney Diseases; the National Eye Institute; the National Institutes of Health; JDRF; and the American Diabetes Association.

About Joslin Diabetes Center

Joslin Diabetes Center is world-renowned for its deep expertise in diabetes treatment and research. Joslin is dedicated to finding a cure for diabetes and ensuring that people with diabetes live long, healthy lives.  We develop and disseminate innovative patient therapies and scientific discoveries throughout the world. Joslin is an independent, non-profit institution affiliated with Harvard Medical School, and one of only 16 NIH-designated Diabetes Research Centers in the U.S.

For more information, visit http://www.joslin.org or follow @joslindiabetes | One Joslin Place, Boston, MA 617-309-2400

Joslin Diabetes Center

Related Diabetes Articles from Brightsurf:

New diabetes medication reduced heart event risk in those with diabetes and kidney disease
Sotagliflozin - a type of medication known as an SGLT2 inhibitor primarily prescribed for Type 2 diabetes - reduces the risk of adverse cardiovascular events for patients with diabetes and kidney disease.

Diabetes drug boosts survival in patients with type 2 diabetes and COVID-19 pneumonia
Sitagliptin, a drug to lower blood sugar in type 2 diabetes, also improves survival in diabetic patients hospitalized with COVID-19, suggests a multicenter observational study in Italy.

Making sense of diabetes
Throughout her 38-year nursing career, Laurel Despins has progressed from a bedside nurse to a clinical nurse specialist and has worked in medical, surgical and cardiac intensive care units.

Helping teens with type 1 diabetes improve diabetes control with MyDiaText
Adolescence is a difficult period of development, made more complex for those with Type 1 diabetes mellitus (T1DM).

Diabetes-in-a-dish model uncovers new insights into the cause of type 2 diabetes
Researchers have developed a novel 'disease-in-a-dish' model to study the basic molecular factors that lead to the development of type 2 diabetes, uncovering the potential existence of major signaling defects both inside and outside of the classical insulin signaling cascade, and providing new perspectives on the mechanisms behind insulin resistance in type 2 diabetes and possibly opportunities for the development of novel therapeutics for the disease.

Tele-diabetes to manage new-onset diabetes during COVID-19 pandemic
Two new case studies highlight the use of tele-diabetes to manage new-onset type 1 diabetes in an adult and an infant during the COVID-19 pandemic.

Genetic profile may predict type 2 diabetes risk among women with gestational diabetes
Women who go on to develop type 2 diabetes after having gestational, or pregnancy-related, diabetes are more likely to have particular genetic profiles, suggests an analysis by researchers at the National Institutes of Health and other institutions.

Maternal gestational diabetes linked to diabetes in children
Children and youth of mothers who had gestational diabetes during pregnancy are at increased risk of diabetes themselves, according to new research published in CMAJ (Canadian Medical Association Journal).

Two diabetes medications don't slow progression of type 2 diabetes in youth
In youth with impaired glucose tolerance or recent-onset type 2 diabetes, neither initial treatment with long-acting insulin followed by the drug metformin, nor metformin alone preserved the body's ability to make insulin, according to results published online June 25 in Diabetes Care.

People with diabetes visit the dentist less frequently despite link between diabetes, oral health
Adults with diabetes are less likely to visit the dentist than people with prediabetes or without diabetes, finds a new study led by researchers at NYU Rory Meyers College of Nursing and East Carolina University's Brody School of Medicine.

Read More: Diabetes News and Diabetes Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.