The diagnosis of Alzheimer’s disease is often made after the onset of typical symptoms such as memory loss, but then the only thing that can be done is to slow down the progression of symptoms.
Some studies have shown that changes associated with Alzheimer’s disease, such as the misfolding and aggregation of beta-amyloid proteins into oligomers, begin to occur in the body years before the diagnosis is made.
In a recent study published in the Proceedings of the National Academy of Sciences (PNAS), researchers at the University of Washington have developed a blood test called SOBA that offers the possibility of early identification of people at risk or latent for Alzheimer’s disease.
Misfolded β-amyloid proteins, when aggregated into oligomers, form a protein secondary structure, α-sheet, which is rare in nature and has a tendency to bind to each other.
The researchers used this feature to design synthetic alpha-sheet structures to bind oligomers in cerebrospinal fluid or blood samples.
Based on this core principle, the researchers developed the SOBA (soluble oligomer binding assay).
The test results showed that SOBA detected oligomers not only in the blood of patients with mild cognitive impairment and moderate to severe Alzheimer’s disease, but also in the blood of 11 healthy controls without mild cognitive impairment.
Ten of these subjects with documented follow-up exams were diagnosed years later as having mild cognitive impairment or pathological changes in the brain consistent with Alzheimer’s disease.
This suggests that SOBA may be able to detect signs of the disease before cognitive impairment occurs, the researchers said.