In seeking a safe yet effective way to predict Alzheimer's disease, researchers found a sugar molecule in the blood of affected patients. When combined with a simple memory test and genetic analysis, the research team was able to predict the onset of the condition up to a decade in advance with a significant degree of accuracy. The protocol could soon join others in helping scientists spot Alzheimer's in advance of its symptoms and take steps to halt its progression.
It seems that almost daily, scientists are getting closer and closer to finding new ways to predict the onset of Alzheimer's disease. We've seen attempts at using wearables to track movement patterns associated with the condition; algorithms that can analyze PET scans to spot signs of the disease years in advance; and analyses that have found 75 genomic regions associated with the disease. Testing of bodily fluids is also showing promise as a predictive modality but, because removing cerebrospinal fluid is always a risky proposition, researchers are trying to work out ways to spot the disease using much simpler blood tests.
That's the case for scientists at Karolinska Institutet (KI) in Sweden. Previously, researchers there showed that sugar-based substances called glycans found in cerebrospinal fluid could be linked to the presence of tau proteins in the body. High levels of abnormal tau in the brain is one of the primary markers of Alzheimer's disease, so finding it early in the body could be a way to predict the onset of the condition. In fact, the team found that people with matching levels of tau and glycans were twice as likely to develop Alzheimer's than those without the markers.
In the new study, the team found that glycans, sugar-based molecules that coat proteins, are also present in the blood. By combining that information with a genetic analysis and a memory test, they could predict the onset of Alzheimer's with 80% accuracy up to 10 years before the symptoms of memory loss appeared.
“The role of glycans, structures made up of sugar molecules, is a relatively unexplored field in dementia research,” says the study’s first author Robin Zhou, medical student and affiliated researcher at KI. “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.”
In working out the data, the research team looked at blood samples collected between 2001 and 2004 from 233 people who had participated in a national Swedish study on aging. Monitoring regarding signs of dementia and memory loss was carried out every three to six years for 17 years in total, so a link between blood chemistry and memory loss could be easily established. As a next step, the researchers will be looking at additional blood samples involved in both the Swedish study as well as aging studies conducted outside the country. The team is also working to put the findings into practice in clinical settings.
“We’re collaborating with researchers in primary care in Sweden to evaluate different biomarkers for dementia at primary health care centers,” said senior study author Schedin Weiss. “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.”
The research has been published in the journal Alzheimer's & Dementia.
Source: Karolinska Institute
