African American Alzheimer's Disease
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Researchers at Karolinska Institute (KI) in Sweden have identified a sugar molecule as a potential new biomarker for Alzheimer’s disease that can be detected in the blood of individuals up to ten years prior to diagnosis.

According to the Alzheimer’s association, nearly seven million Americans are suffering from the disease, with the number being expected to have almost doubled by 2050. Because early detection of Alzheimer’s is crucial to prevent irreversible damage to neurons, the hunt for biomarkers that could be used to predict the illness before it’s too late, is at an all time high.

Reporting in Alzheimer’s & Dementia, scientists at KI have now shown that the blood levels of a certain glycan, called bisected N-acetylglucosamine, can be used to predict the risk of an individual developing Alzheimer’s disease in the future. Glycans are sugar molecules found on the surface of proteins allowing scientists to localize them.

“The role of glycans, structures made up of sugar molecules, is a relatively unexplored field in dementia research,” said Robin Zhou, medical student and affiliated researcher at the Department of Neurobiology, Care Sciences and Society (NVS), KI and first author of the study.

“We demonstrate in our study that blood levels of glycans are altered early during the development of the disease. This could mean that we’ll be able to predict the risk of Alzheimer’s disease with only a blood test and a memory test.”

The researchers determined that elevated levels of the sugar correlated with an increase in tau protein— a well-known biomarker for the disease. Individuals with matching levels of glycans and tau were more than twice as likely to develop Alzheimer’s-type dementia than those without.

“We also show that a simple statistical model that take into account blood glycan and tau levels, the risk gene APOE4 and a memory test, can be used to predict Alzheimer’s disease to a reliability of 80 per cent almost a decade before symptoms such as memory loss appear,” said corresponding author Sophia Schedin Weiss, docent at NVS, KI in a press statement.

The study was conducted using results from over 200 participants of the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K). The individuals were monitored in regular intervals for a total duration of 17 years. Factors checked during the follow-ups involved memory loss as well as the presence of dementia.

To further understand the role of the biomarker in Alzheimer’s pathology, the researchers want to analyze blood samples from participants of more aging studies around the world.

“We’re collaborating with researchers in primary care in Sweden to evaluate different biomarkers for dementia at primary health care centres. We hope that glycans in the blood will prove to be a valuable complement to current methods of screening people for Alzheimer’s disease that will enable the disease to be detected early,” Weiss concluded.

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