Researchers have developed a new blood test that could detect abnormal proteins circulating in the blood early in the disease process and 15 to 20 years before the usual diagnosis.
Incurable, Alzheimer’s disease can however be slowed down if diagnosed early. This is unfortunately not the case since it is generally diagnosed too late, when the first clinical symptoms appear.
Researchers have developed a new blood biomarker that could detect abnormal proteins that exist at an early stage in Alzheimer’s disease. Their results are published in the journal EMBO April 6, 2018.
Detect the molecular mechanism as early as possible
Today, Alzheimer’s disease detection tools are limited to costly or invasive examinations: positron emission tomography (PET) and cerebrospinal fluid puncture. In addition, they only allow a diagnosis that is already quite late. The development of a minimally invasive blood biomarker for screening preclinical stages was therefore crucial. A new immunological method is based on antibodies which make it possible to extract from samples of CSF and blood all the proteins whose structure has been modified and which circulate in the blood at an early stage.
This immuno-infrared test detects the misfolding of proteins during their shaping, a process that occurs 15 to 20 years before the clinical manifestation of the disease. This new plasma biomarker allows the early identification of Alzheimer’s disease with a sensitivity of 71% and a specific of 91%. It could also help identify people at risk of developing Alzheimer’s disease, pre-select individuals for lumbar puncture or PET scans, and rule out false positives.
Differentiate Alzheimer’s disease from other forms of dementia
Alzheimer’s disease is a neurological disorder characterized by the deposition of amyloid plaques and neurofibrillary tangles in the brain. Researchers have developed an immuno-infrared sensor making it possible to monitor the change in the secondary structure of amyloid proteins from their healthy state, “α-helical”, to their “β-pathological” state. These pathological structures aggregate and can form soluble toxic oligomers contributing to neurodegeneration.
According to the researchers, the test reliably detects alterations in β-amyloid proteins in the blood of people with only mild cognitive impairment. But it could also make it possible to highlight other neurodegenerative folds, such as those found in Parkinson’s disease. In the latter, this new test could make it possible to quantify α-synuclein, a biomarker of the disease.
In the field of neurodegenerative diseases, drug research is generally hampered by the fact that the disease can only be diagnosed when it is too late to intervene effectively. The researchers’ discovery opens the way to new possibilities for the development of treatments.
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