Blood test indicates risk of dementia
A simple blood test can detect Alzheimer’s disease. Before this scientific breakthrough, detecting proteins and confirming the diagnosis of the disease was only possible using an expensive PET scan or an invasive lumbar puncture. Now, thanks to new research that complements previous ones, the risk of developing dementia can be predicted 15 years before diagnosis.
Hopes for the test were raised after scientists found biological markers of the disease in blood samples collected from more than 50,000 healthy volunteers participating in the UK Biobank project. The blood test revealed patterns of four proteins that predict the onset of dementia in general, and Alzheimer’s disease and vascular dementia in particular in later life.
Combined with more traditional risk factors such as age, gender, education and genetic predisposition, the protein profiles allowed the researchers to predict dementia. With an estimated accuracy of 90%, people had received clinical confirmation of the disease almost 15 years earlier.
Globally, more than 55 million people live with dementia, and this number is expected to reach 78 million by 2030. About 70% of them are caused by Alzheimer’s disease. While vascular dementia, caused by damage to blood vessels, accounts for 20% of cases, says a study published in the journal Nature. Dementia is a term covering several diseases that affect memory, thinking and the ability to carry out daily activities.
“We hope to develop this screening kit that can be used in the NHS,” said Professor Jianfeng Feng from the University of Warwick and Fudan University in China.
Early diagnosis of dementia
A number of recent studies have shown the potential of blood tests to identify patients most likely to develop dementia. Armed with this information, doctors could determine which patients should be referred for additional testing, including full diagnostic testing for Alzheimer’s disease.
Early confirmation of the disease is crucial if patients are to benefit from two new Alzheimer’s drugs, lecanemab and donanemab, which are under review by Britain’s medicines regulator. If licensed, the National Institute for Health and Care Excellence will consider the costs and benefits before deciding whether they should be available on the NHS.
The US Food and Drug Administration has approved lecanemab and is expected to rule on donanemab soon. He recalled that European regulators are still reviewing both drugs. The keeper.
For patients to receive lecanemab or donanemab, they must have early stage Alzheimer’s disease and a lumbar puncture or PET scan to confirm the presence of amyloid protein in the brain. Toxic accumulations of amyloid are one of the signs of the disease. However, Alzheimer’s Research UK estimates that only 2% of eligible patients undergo such tests.
Work is underway to develop and implement simple blood tests to diagnose Alzheimer’s disease, but even with rapid diagnosis of dementia, challenges remain.
New medications must be given to patients every two weeks, and because of potentially fatal side effects, patients must undergo regular MRI scans to look for swelling or bleeding in the brain.
Tracking four proteins
Using artificial intelligence, the researchers looked for links between nearly 1,500 blood proteins and the development of dementia years later. In the paper, they describe how four proteins, Gfap, Nefl, Gdf15 and Ltbp2, were present at unusual levels in those who developed all-cause dementia, Alzheimer’s disease or vascular dementia.
Higher protein levels were warning signs of the disease. Inflammation in the brain can cause cells called astrocytes to overproduce Gfap, a known biomarker for Alzheimer’s disease. The study found that people with high levels of Gfap were more than twice as likely to develop dementia as people with lower levels.
Another blood protein, Nefl, is associated with nerve fiber damage. While higher than normal levels of Gdf15 can occur after damage to the blood vessels of the brain. Scientists have found that increased levels of Gfap and Ltbp2 are highly specific to dementia and not to other brain diseases. And the changes occurred at least 10 years before people were diagnosed with dementia.
Researchers are in talks with companies to develop a test, but say its cost must be reduced to make it viable.
“This new study adds to growing evidence that studying the levels of certain proteins in the blood of healthy people can accurately predict dementia before symptoms develop,” said Sheona Scales, director of research at Alzheimer’s Research UK.
More research is needed to understand how well these tests work in more diverse populations, Scales added.
Benefits for patients
Jianfeng Feng emphasized that the combination of artificial intelligence and protein analysis offers promising opportunities for precision medicine. This is very important for early diagnosis among middle-aged and older people in the community who are at high risk of dementia. “This model can be integrated into the NHS (National Health Service). And be used as a screening tool by primary care physicians,” he said.
Likewise, Wei Cheng, co-author of the study and an academician at Fudan University, explained the details of the study. He said this was based on a dementia prediction model previously developed by the team, which used variables such as age, presence of a particular gene and maternal age at death. “Compared with our previous work,” he noted, “the newly developed protein-based model is obviously a great achievement.”
Another collaborator, Professor Jintai Yu, a specialist in neurovegetative diseases at Fudan University, added that “proteomic biomarkers are more easily accessible and non-invasive. “And they can greatly facilitate large-scale population screening.”
He also pointed out the shortcomings of previous risk models. Thus, they largely depended on complex biomarkers that were difficult to obtain using procedures such as lumbar puncture or sophisticated imaging techniques.
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