Alzheimer’s disease is usually diagnosed when patients show signs of memory loss and other cognitive impairments. However, research suggests that the underlying cause of Alzheimer’s, the accumulation of amyloid beta protein aggregates called oligomers, begins years or even decades before these symptoms appear.
Researchers at the University of Washington have developed a laboratory test called SOBA (soluble oligomer binding assay) that can measure levels of amyloid beta oligomers in blood samples.
The SOBA research team ran the test on blood samples from 310 research subjects who had no signs of cognitive impairment, mild cognitive impairment, Alzheimer’s disease, or another form of dementia at the time the blood samples were taken. The test was able to detect oligomers in the blood of patients with Alzheimer’s disease, but not in most members of a control group without cognitive impairments. However, the test did detect oligomers in the blood of 11 individuals from the control group who were later diagnosed with mild cognitive impairment or brain pathology consistent with Alzheimer’s disease. This suggests that the test may be able to detect the presence of toxic oligomers before symptoms of Alzheimer’s disease appear.
SOBA was able to detect amyloid beta oligomers in the blood of individuals with mild cognitive impairment and moderate to severe Alzheimer’s disease. In 53 cases, the research subjects’ diagnoses of Alzheimer’s were later confirmed by autopsy, and the blood samples of 52 of them contained toxic oligomers.
SOBA also detected oligomers in the blood of members of the control group who later developed mild cognitive impairment. The team behind SOBA is working to develop the test into a diagnostic tool for oligomers and is also exploring the possibility of modifying it to detect toxic oligomers of another protein associated with Parkinson’s disease and Lewy body dementia.