Alzheimer's disease: A sugar molecule may help with earlier diagnosis

  • New research shows a connection between glycans (sugar molecules in the blood) and tau (proteins that play a role in the development of dementia).
  • The data could open the door to low-cost, non-invasive diagnoses that could predict Alzheimer’s disease up to a decade in advance.
  • With dementia and Alzheimer’s diagnoses on the rise, there’s increased need for better diagnostic and treatment options.
  • The researchers’ goal is to provide doctors with a better way to predict Alzheimer’s before onset.

Researchers are reporting a connection between sugar molecules in the bloodstream and Alzheimer’s disease — a discovery they say could lead to an inexpensive, effective screening procedure that could diagnose the disease years before onset.

The researchers from Karolinska Institute in Stockholm, Sweden, published their findings this week in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association.

Robin Zhou, the study’s first author and a medical student and affiliated researcher at the Department of Neurobiology, Care Sciences and Society at Karolinska Insitute, told Medical News Today that the data builds on prior research by the same group that found a link between tau proteins — which are known to play a role in the development of neurobiological disorders — and the levels of a specific glycan.

“Just as in cerebrospinal fluid, we discovered a correlation between levels of this glycan epitope and levels of the pathogenic tau protein, linking this glycan to Alzheimer’s pathogenesis,” he explained. “However, we were surprised to find that when analyzing the glycan to tau ratio in individuals, it seemed to be able to predict Alzheimer’s disease up to a decade before diagnosis.”

Given the fact that there’s a need for low-cost, non-invasive screening screening methods for Alzheimer’s, the researchers say the findings couldn’t have come at a better time.

Earlier intervention in Alzheimer’s treatment

Zhou said that he and his colleagues have the ultimate goal of providing doctors with a better way to predict Alzheimer’s disease before its onset.

“It is especially relevant since the FDA (U.S. Food and Drug Administration) recently approved another Alzheimer’s drug, lecanemab,” Zhou emphasized. “Potential treatments would be more effective if initiated at an early stage of the disease. We believe that glycans may be a valuable complement to current biomarkers and can help subgrouping patients with different phenotypes and may need different treatment approaches.”

Jim Jackson, PsyD, a neuropsychologist and professor of medicine at Vanderbilt Medical Center in Tennessee and the author of the book Clearing the Fog: From Surviving to Thriving with Long Covid — A Practical Guide, told Medical News Today that there are currently a number of hurdles when it comes to diagnosing dementia or Alzheimer’s — particularly in the early stages of onset.

“One of these challenges, candidly, is the lack of specialists who are experts in the diagnosis of conditions like Alzheimer’s disease, let alone forms of cognitive impairment that are rarer,” he said. “If you live in a large urban center and have access to one of dozens of NIH funded Alzheimer’s Disease Research Centers or to a memory clinic, places offering state of the art diagnostics, the diagnostic process can be straightforward, but if you are relying on a primary care provider with limited expert knowledge, a lot of imprecision abounds.”

While Alzheimer’s is a degenerative and ultimately fatal disease, early intervention can make a big difference when it comes to quality of life.

“One benefit is that treatments, although often limited, tend to be more effective in the early days of the disease,” said Jackson. “Another is that early in the process, while patients still have some degree of cognitive ability, they can be active in the decision-making process — something that is very difficult for people later in the course of the illness. Yet another is that if there are goals, dreams, things of importance to pursue from a bucket list — this can be done, goodbyes can be said, feelings can be shared, because in the beginning of a long season of dementia, patients are often still lucid.”

Addressing an important public health issue

Millions of older adults are affected by dementia — a catch-all term that includes Alzheimer’s disease — and the numbers are predicted to rise.

Jackson says that one of the ripple effects of the COVID-19 pandemic is cognitive decline in older adults.

“Any current conversation about dementia is incomplete unless we discuss the pandemic and the many ways that this this has been harmful for brain health, especially in the elderly, who are the most vulnerable among us,” he said.

“Living through the pandemic, for so many seniors, has been hard and the isolation, loneliness, and anxiety it has caused, coupled with an absence of social support has really accelerated cognitive decline in many people, not to mention those who developed COVID and survived either a mild or severe ICU related case, and who have an increased risk of dementia as a result,” Jackson added. “We really need to mobilize our resources to help these people because, sadly, a crisis is brewing.”

While a cure for Alzheimer’s isn’t in the cards, new medications such as lecanemab and new insights like those from the Karolinska Institute show that progress is being made in terms of identifying and managing the disease.

“In order to find a more effective treatment, therapies may need to be tailored to individual patients depending on their disease subtype,” Zhou explained. “Here [in our research], existing and novel biomarkers play an important role in determining subtypes of the disease.”

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